Science.gov

Sample records for active normal modes

  1. The KRAKEN normal mode program

    NASA Astrophysics Data System (ADS)

    Porter, M. B.

    1992-05-01

    In the late 1970's, several normal-mode models existed which were widely used for predicting acoustic transmission-loss in the ocean; however, each had its own problems. Typical difficulties included numerical instabilities for certain types of sound-speed profiles and failures to compute a complete set of ocean modes. In short, there was a need for a model that was robust, accurate, and efficient. In order to resolve these problems, a new algorithm was developed forming the basis for the KRAKEN normal mode model. Over subsequent years, KRAKEN was greatly extended, with options for modeling ocean environments that are range-independent, range-dependent, or fully 3-dimensional. The current version offers the specialist a vast number of options for treating ocean-acoustics problems (or more generally acousto-elastic waveguides). On the other hand, it is easy for a less sophisticated user to learn the small subset of tools needed for the common problem of transmission-loss modeling in range-independent ocean environments. This report addresses the need for a more complete user's guide to supplement the on-line help files. The first chapters give a fairly technical description of the mathematical and numerical basis of the model. Additional chapters give a simpler description of its use and installation in a manner that is accessible to less scientifically-oriented readers.

  2. Zwitterion L-cysteine adsorbed on the Au₂₀ cluster: enhancement of infrared active normal modes.

    PubMed

    Tlahuice-Flores, Alfredo

    2013-04-01

    The study reported herein addressed the structure, adsorption energy and normal modes of zwitterion L-cysteine (Z-cys) adsorbed on the Au₂₀ cluster by using density functional theory (DFT). It was found that four Z-cys are bound to the Au₂₀ apexes preferentially through S atoms. Regarding normal modes, after adsorption of four Z-cys molecules, a more intense infrared (IR) peak is maintained around 1,631.4 cm(-1) corresponding with a C=O stretching mode, but its intensity is enhanced approximately six times. The enhancement in the intensity of modes between 0 to 300 cm(-1) is around 4.5 to 5.0 times for normal modes that involve O-C=O and C-S bending modes. Other two normal modes in the range from 300 to 3,500 cm(-1) show enhancements of 6.0 and 7.4 times. In general, four peaks show major intensities and they are related with normal modes of carboxyl and NH₃ groups of Z-cys.

  3. The effective degeneracy of protein normal modes.

    PubMed

    Na, Hyuntae; Song, Guang

    2016-01-01

    Normal modes are frequently computed and used to portray protein dynamics and interpret protein conformational changes. In this work, we investigate the nature of normal modes and find that the normal modes of proteins, especially those at the low frequency range (0-600 cm(-1)), are highly susceptible to degeneracy. Two or more modes are degenerate if they have the same frequency and consequently any orthogonal transformation of them also is a valid representation of the mode subspace. Thus, degenerate modes can no longer characterize unique directions of motions as regular modes do. Though the normal modes of proteins are usually of different frequencies, the difference in frequency between neighboring modes is so small that, under even slight structural uncertainty that unavoidably exists in structure determination, it can easily vanish and as a result, a mode becomes effectively degenerate with its neighboring modes. This can be easily observed in that some modes seem to disappear and their matching modes cannot be found when the structure used to compute the modes is modified only slightly. We term this degeneracy the effective degeneracy of normal modes. This work is built upon our recent discovery that the vibrational spectrum of globular proteins is universal. The high density of modes observed in the vibrational frequency spectra of proteins renders their normal modes highly susceptible to degeneracy, under even the smallest structural uncertainty. Indeed, we find the degree of degeneracy of modes is proportional to the density of modes in the vibrational spectrum. This means that for modes at the same frequency, degeneracy is more severe for larger proteins. Degeneracy exists also in the modes of coarse-grained models, but to a much lesser extent than those of all-atom models. In closing, we discuss the implications of the effective degeneracy of normal modes: how it may significantly affect the ways in which normal modes are used in various normal modes

  4. Gravity wave diagnosis using empirical normal modes

    NASA Astrophysics Data System (ADS)

    Charron, Martin

    We adapt the theory of Empirical Normal Modes (ENMs) to diagnose gravity waves generated by a relatively high resolution numerical model solving the primitive equations. The ENM approach is based on the Principal Component Analysis (which consists of finding the most efficient basis explaining the variance of a time series), except that it takes advantage of wave-activity conservation laws. In the present work, the small- amplitude version of the pseudoenergy is used to extract from data quasi-monochromatic three-dimensional empirical modes that describe atmospheric wave activity. The spatial distributions of these quasi-monochromatic modes are identical to the normal modes of the linearized primitive equations when the underlying dynamics can be described with a stochastic linear and forced model, thus establishing a bridge between statistics and dynamics. We use this diagnostic method to study inertia-gravity wave generation, propagation, transience, and breaking over the Rockies, the North Pacific, and Central America in the troposphere-stratosphere-mesosphere GFDL SKYHI general circulation model at a resolution of 1° of latitude by 1.2° of longitude. Besides the action of mountains in exciting orographic waves, inertia-gravity wave activity has been found to be generated at the jet stream level as a possible consequence of a sustained nonlinear and ageostrophic flow. In the Tropical region of the model, the ``obstacle effect'' has been found to be the major source of inertia-gravity waves. A significant proportion of these inertia-gravity waves was able to reach the model mesosphere without much dissipation and absorption.

  5. Dynamic reorganization of the functionally active ribosome explored by normal mode analysis and cryo-electron microscopy.

    PubMed

    Tama, Florence; Valle, Mikel; Frank, Joachim; Brooks, Charles L

    2003-08-01

    Combining structural data for the ribosome from x-ray crystallography and cryo-electron microscopy with dynamic models based on elastic network normal mode analysis, an atomically detailed picture of functionally important structural rearrangements that occur during translocation is elucidated. The dynamic model provides a near-atomic description of the ratchet-like rearrangement of the 70S ribosome seen in cryo-electron microscopy, and permits the identification of bridging interactions that either facilitate the conformational switching or maintain structural integrity of the 50S/30S interface. Motions of the tRNAs residing in the A and P sites also suggest the early stages of tRNA translocation as a result of this ratchet-like movement. Displacement of the L1 stalk, alternately closing and opening the intersubunit space near the E site, is observed in the dynamic model, in line with growing experimental evidence for the role of this structural component in facilitating the exiting of tRNA. Finally, a hinge-like transition in the 30S ribosomal subunit, similar to that observed in crystal structures of this complex, is also manifest as a dynamic mode of the ribosome. The coincidence of these dynamic transitions with the individual normal modes of the ribosome and the good correspondence between these motions and those observed in experiment suggest an underlying principle of nature to exploit the shape of molecular assemblies such as the ribosome to provide robustness to functionally important motions. PMID:12878726

  6. Black hole normal modes - A semianalytic approach

    NASA Technical Reports Server (NTRS)

    Schutz, B. F.; Will, C. M.

    1985-01-01

    A new semianalytic technique for determining the complex normal mode frequencies of black holes is presented. The method is based on the WKB approximation. It yields a simple analytic formula that gives the real and imaginary parts of the frequency in terms of the parameters of the black hole and of the field whose perturbation is under study, and in terms of the quantity (n + 1/2), where n = 0, 1, 2,... and labels the fundamental mode, first overtone mode, and so on. In the case of the fundamental gravitational normal modes of the Schwarzschild black hole, the WKB estimates agree with numerical results to better than 7 percent in the real part of the frequency and 0.7 percent in the imaginary part, with the relative agreement improving with increasing angular harmonic. Carried to higher order the method may provide an accurate and systematic means to study black hole normal modes.

  7. Normal Modes of Black Hole Accretion Disks

    SciTech Connect

    Ortega-Rodriguez, Manuel; Silbergleit, Alexander S.; Wagoner, Robert V.; /Stanford U., Phys. Dept. /KIPAC, Menlo Park

    2006-11-07

    This paper studies the hydrodynamical problem of normal modes of small adiabatic oscillations of relativistic barotropic thin accretion disks around black holes (and compact weakly magnetic neutron stars). Employing WKB techniques, we obtain the eigen frequencies and eigenfunctions of the modes for different values of the mass and angular momentum of the central black hole. We discuss the properties of the various types of modes and examine the role of viscosity, as it appears to render some of the modes unstable to rapid growth.

  8. World ocean tides synthesized from normal modes.

    PubMed

    Platzman, G W

    1983-05-01

    Sixty oceanic normal modes are used to synthesize the M(2) and K(1) (principal lunar semidiurnal and declinational diurnal) tides. The ten most energetic modes in the M(2) synthesis account for 87 percent of the energy; the corresponding figure for K(1) is 93 percent, two-thirds of which is contributed by a single mode whose natural period is about 29 hours. Model calculations indicate that the quality (Q) of the ocean response to tidal forcing resembles that of a frictionally controlled oscillator. In particular, for M(2) the global Q is about 10. PMID:17749537

  9. Normal modes of confined cold ionic systems

    SciTech Connect

    Schiffer, J.P.; Dubin, D.H.

    1995-08-01

    The normal modes of a cloud of confined ions forming a strongly-correlated plasma were investigated. The results of molecular-dynamics simulations were compared to predictions of a cold fluid mode. Mode frequencies are observed to shift slightly compared to the cold fluid predictions, and the modes are also observed to damp in time. Simulations also reveal a set of torsional oscillations which have no counterpart in cold fluid theory. The frequency shift, damping, and torsional effects are compared to a model that treats trapped plasmas as a visco-elastic spheroid. It may be possible to measure high-frequency bulk and shear moduli of a strongly-correlated plasma from mode excitation experiments on trapped non-neutral plasmas. An example of the results of the calculation is presented.

  10. A spectral characterization of nonlinear normal modes

    NASA Astrophysics Data System (ADS)

    Cirillo, G. I.; Mauroy, A.; Renson, L.; Kerschen, G.; Sepulchre, R.

    2016-09-01

    This paper explores the relationship that exists between nonlinear normal modes (NNMs) defined as invariant manifolds in phase space and the spectral expansion of the Koopman operator. Specifically, we demonstrate that NNMs correspond to zero level sets of specific eigenfunctions of the Koopman operator. Thanks to this direct connection, a new, global parametrization of the invariant manifolds is established. Unlike the classical parametrization using a pair of state-space variables, this parametrization remains valid whenever the invariant manifold undergoes folding, which extends the computation of NNMs to regimes of greater energy. The proposed ideas are illustrated using a two-degree-of-freedom system with cubic nonlinearity.

  11. Global normal mode planetary wave activity: a study using TIMED/SABER observations from the stratosphere to the mesosphere-lower thermosphere

    NASA Astrophysics Data System (ADS)

    John, Sherine Rachel; Kumar, Karanam Kishore

    2016-02-01

    A comprehensive study of three normal mode travelling planetary waves, namely the quasi-16, -10 and -5 day waves, is carried out globally using 5 years (2003-2007) of TIMED/SABER temperature measurements from the stratosphere to the mesosphere-lower thermosphere (MLT) by employing the two dimensional Fourier decomposition technique. From preliminary analysis, it is found that significant amplitudes of normal modes are confined to wave numbers-2 (westward propagating modes) to 2 (eastward propagating modes). The westward propagating quasi 16-day waves with zonal wave number 1 (W1; W1 refers to westward propagating wave with zonal wave number 1) peaks over winter-hemispheric high latitudes with northern hemisphere (NH) having higher amplitudes as compared to their southern hemispheric (SH) counterpart. The W1 quasi 16-day waves exhibit a double peak structure in altitude over winter hemispheric high latitudes. The eastward propagating quasi 16-day waves with wave number 1 (E1; E1 refers to eastward propagating wave with zonal wave number 1) exhibits similar features as that of W1 waves in the NH. In contrast, the E1 quasi 16-day waves in the SH show larger amplitudes as compared to the W1 waves and they do not exhibit double peak structure in altitude. Similar to the quasi 16-day waves, the quasi 10- and 5-day wave amplitudes with respect to their wavenumbers are delineated. Unlike quasi-16 and -10 day waves, quasi-5 day waves peak during vernal equinox both in the SH and NH. The peak activity of the W1 quasi-5 day wave is centered around 40°N and 40°S exhibiting symmetry with respect to the equator. A detailed discussion on the height-latitude structure, interannual variability and inter-hemispheric propagation of quasi 16-, 10- and 5-day waves are discussed. The significance of the present study lies in establishing the 5-year climatology of normal mode planetary waves from the stratosphere to the MLT region including their spatial-temporal evolution, which are

  12. Wave Forced Normal Modes on Fringing Reefs

    NASA Astrophysics Data System (ADS)

    Pequignet, A. N.; Becker, J. M.; Merrifield, M. M.; Aucan, J.

    2008-12-01

    In an effort to assess wave-driven coastal inundation at the shoreline of fringing reefs, pressure and current observations were collected at reefs on Guam (Ipan) and Oahu, Hawaii (Mokuleia) as part of the PILOT (Pacific Island Land-Ocean Typhoon) experiment. Similar to dissipative sandy beaches, nearshore surface elevation at both reefs is dominated by energy in the infragravity frequency band. Coherent infragravity oscillations across the reef tend to occur at discrete frequencies and with standing wave cross-shore structures that are consistent with open basin resonant modes. The modes are forced by swell wave groups, similar to a time-dependent setup. The resonant modes are most apparent during energetic wave events, in part because wave setup over the reef increases the low mode resonant frequencies to a range that is conducive to wave group forcing. Evidence of the excitation of resonant modes during tropical storm Man-Yi at Ipan, Guam is presented.

  13. Atmospheric Excitation of Planetary Normal Modes

    NASA Technical Reports Server (NTRS)

    Tanimoto, Toshiro

    2001-01-01

    The objectives of this study were to: (1) understand the phenomenon of continuous free oscillations of the Earth and (2) examine the idea of using this phenomenon for planetary seismology. We first describe the results on (1) and present our evaluations of the idea (2) in the final section. In 1997, after almost forty years since the initial attempt by Benioff et al, continuous free oscillations of the Earth were discovered. Spheroidal fundamental modes between 2 and 7 millihertz are excited continuously with acceleration amplitudes of about 0.3-0.5 nanogals. The signal is now commonly found in virtually all data recorded by STS-1 type broadband seismometers at quiet sites. Seasonal variation in amplitude and the existence of two coupled modes between the atmosphere and the solid Earth support that these oscillations are excited by the atmosphere. Stochastic excitation due to atmospheric turbulence is a favored mechanism, providing a good match between theory and data. The atmosphere has ample energy to support this theory because excitation of these modes require only 500-10000 W whereas the atmosphere contains about 117 W of kinetic energy. An application of this phenomenon includes planetary seismology, because other planets may be oscillating due to atmospheric excitation. The interior structure of planets could be learned by determining the eigenfrequencies in the continuous free oscillations. It is especially attractive to pursue this idea for tectonically quiet planets, since quakes may be too infrequent to be recorded by seismic instruments.

  14. Instantaneous Normal Modes and the Protein Glass Transition

    PubMed Central

    Schulz, Roland; Krishnan, Marimuthu; Daidone, Isabella; Smith, Jeremy C.

    2009-01-01

    Abstract In the instantaneous normal mode method, normal mode analysis is performed at instantaneous configurations of a condensed-phase system, leading to modes with negative eigenvalues. These negative modes provide a means of characterizing local anharmonicities of the potential energy surface. Here, we apply instantaneous normal mode to analyze temperature-dependent diffusive dynamics in molecular dynamics simulations of a small protein (a scorpion toxin). Those characteristics of the negative modes are determined that correlate with the dynamical (or glass) transition behavior of the protein, as manifested as an increase in the gradient with T of the average atomic mean-square displacement at ∼220 K. The number of negative eigenvalues shows no transition with temperature. Further, although filtering the negative modes to retain only those with eigenvectors corresponding to double-well potentials does reveal a transition in the hydration water, again, no transition in the protein is seen. However, additional filtering of the protein double-well modes, so as to retain only those that, on energy minimization, escape to different regions of configurational space, finally leads to clear protein dynamical transition behavior. Partial minimization of instantaneous configurations is also found to remove nondiffusive imaginary modes. In summary, examination of the form of negative instantaneous normal modes is shown to furnish a physical picture of local diffusive dynamics accompanying the protein glass transition. PMID:19167298

  15. Instantaneous Normal Modes and the Protein Glass Transition

    SciTech Connect

    Schultz, Roland; Krishnan, Marimuthu; Daidone, Isabella; Smith, Jeremy C

    2009-01-01

    In the instantaneous normal mode method, normal mode analysis is performed at instantaneous configurations of a condensed-phase system, leading to modes with negative eigenvalues. These negative modes provide a means of characterizing local anharmonicities of the potential energy surface. Here, we apply instantaneous normal mode to analyze temperature-dependent diffusive dynamics in molecular dynamics simulations of a small protein (a scorpion toxin). Those characteristics of the negative modes are determined that correlate with the dynamical (or glass) transition behavior of the protein, as manifested as an increase in the gradient with T of the average atomic mean-square displacement at 220 K. The number of negative eigenvalues shows no transition with temperature. Further, although filtering the negative modes to retain only those with eigenvectors corresponding to double-well potentials does reveal a transition in the hydration water, again, no transition in the protein is seen. However, additional filtering of the protein double-well modes, so as to retain only those that, on energy minimization, escape to different regions of configurational space, finally leads to clear protein dynamical transition behavior. Partial minimization of instantaneous configurations is also found to remove nondiffusive imaginary modes. In summary, examination of the form of negative instantaneous normal modes is shown to furnish a physical picture of local diffusive dynamics accompanying the protein glass transition.

  16. Synthetic normal-mode spectra: a full-coupling perspective

    NASA Astrophysics Data System (ADS)

    Yang, H. Y.; Tromp, J.

    2014-12-01

    Normal-mode spectra may be used to investigate the large-scale anelastic structure of the entire earth. The relevant theory was developed a few decades ago, however, mainly due to computational limitations, several approximations are commonly employed, and thus far the full merits of the complete theory have not been taken advantage of. In this study, we present an exact algebraic form of the theory for an aspherical, anelastic and rotating earth model in which either complex or real spherical harmonic bases are used. Physical dispersion is incorporated into the quadratic eigenvalue problem by expanding the logarithmic frequency term to 2nd order. In addition, we carry out numerical experiments up to 3 mHz to quantitatively evaluate the accuracy of commonly used approximate mode synthetics. We find that (1) approximating mode frequencies for realistic earth models with an average over degenerate frequencies of two coupled modes for physical dispersion, Coriolis effects and perturbed kinematic energy terms gives rise to subtle differences in mode spectra; (2) taking into account the exact normalization of modes instead of the one for a spherical, non-rotation model improves mode spectra by ~2%; (3) consideration of mode coupling in a narrow frequency band yields up to 10% discrepancies in mode spectra compared with wide-band coupling, indicating that the popular splitting function approach may introduce slight biases in normal-mode tomography.

  17. High-Frequency Normal Mode Propagation in Aluminum Cylinders

    USGS Publications Warehouse

    Lee, Myung W.; Waite, William F.

    2009-01-01

    Acoustic measurements made using compressional-wave (P-wave) and shear-wave (S-wave) transducers in aluminum cylinders reveal waveform features with high amplitudes and with velocities that depend on the feature's dominant frequency. In a given waveform, high-frequency features generally arrive earlier than low-frequency features, typical for normal mode propagation. To analyze these waveforms, the elastic equation is solved in a cylindrical coordinate system for the high-frequency case in which the acoustic wavelength is small compared to the cylinder geometry, and the surrounding medium is air. Dispersive P- and S-wave normal mode propagations are predicted to exist, but owing to complex interference patterns inside a cylinder, the phase and group velocities are not smooth functions of frequency. To assess the normal mode group velocities and relative amplitudes, approximate dispersion relations are derived using Bessel functions. The utility of the normal mode theory and approximations from a theoretical and experimental standpoint are demonstrated by showing how the sequence of P- and S-wave normal mode arrivals can vary between samples of different size, and how fundamental normal modes can be mistaken for the faster, but significantly smaller amplitude, P- and S-body waves from which P- and S-wave speeds are calculated.

  18. Assessing the Comprehensive Seismic Earth Model using normal mode data

    NASA Astrophysics Data System (ADS)

    Koelemeijer, Paula; Afanasiev, Michael; Fichtner, Andreas; Gokhberg, Alexey

    2016-04-01

    Advances in computational resources and numerical methods allow the simulation of realistic seismic wave propagation through complex media, while ensuring that the complete wave field is correctly represented in synthetic seismograms. This full waveform inversion is widely applied on regional and continental scales, where particularly dense data sampled can be achieved leading to an increased resolution in the obtained model images. On a global scale, however, full waveform tomography is still and will continue to be limited to longer length scales due to the large computational costs. Normal mode tomography provides an alternative fast full waveform approach for imaging seismic structures in a global way. Normal modes are not limited by the poor station-earthquake distribution and provide sensitivity to density structure. Using normal modes, a more robust long wavelength background model can be obtained, leading to more accurate absolute velocity models for tectonic and mineral physics interpretations. In addition, it is vital to combine all seismic data types across accessible periods to obtain a more complete, consistent and interpretable image of the Earth's interior. Here, we aim to combine the globally sensitive long period normal modes with shorter period full waveform modelling within the multi-scale framework of the Comprehensive Seismic Earth Model (CSEM). The multi-scale inversion framework of the CSEM allows exploitation of the full waveform capacity on both sides of the seismic spectrum. As the CSEM includes high-resolution subregions with velocity variations at much shorter wavelengths than normal modes could constrain, the question arises whether these small-scale variations are noticeable in normal mode data, and which modes respond in particular. We report here on experiments in which we address these questions. We separately investigate the effects of small-scale variations in shear-wave velocity and compressional wave velocity compared to the

  19. Universal spectrum of normal modes in low-temperature glasses

    PubMed Central

    Franz, Silvio; Parisi, Giorgio; Urbani, Pierfrancesco; Zamponi, Francesco

    2015-01-01

    We report an analytical study of the vibrational spectrum of the simplest model of jamming, the soft perceptron. We identify two distinct classes of soft modes. The first kind of modes are related to isostaticity and appear only in the close vicinity of the jamming transition. The second kind of modes instead are present everywhere in the glass phase and are related to the hierarchical structure of the potential energy landscape. Our results highlight the universality of the spectrum of normal modes in disordered systems, and open the way toward a detailed analytical understanding of the vibrational spectrum of low-temperature glasses. PMID:26561585

  20. Universal spectrum of normal modes in low-temperature glasses.

    PubMed

    Franz, Silvio; Parisi, Giorgio; Urbani, Pierfrancesco; Zamponi, Francesco

    2015-11-24

    We report an analytical study of the vibrational spectrum of the simplest model of jamming, the soft perceptron. We identify two distinct classes of soft modes. The first kind of modes are related to isostaticity and appear only in the close vicinity of the jamming transition. The second kind of modes instead are present everywhere in the glass phase and are related to the hierarchical structure of the potential energy landscape. Our results highlight the universality of the spectrum of normal modes in disordered systems, and open the way toward a detailed analytical understanding of the vibrational spectrum of low-temperature glasses. PMID:26561585

  1. Normal mode Rossby waves observed in the upper stratosphere

    NASA Technical Reports Server (NTRS)

    Hirooka, T.; Hirota, I.

    1985-01-01

    In recent years, observational evidence has been obtained for westward traveling planetary waves in the middle atmosphere with the aid of global data from satellites. There is no doubt that the fair portion of the observed traveling waves can be understood as the manifestation of the normal mode Rossby waves which are theoretically derived from the tidal theory. Some observational aspects of the structure and behavior of the normal model Rossby waves in the upper stratosphere are reported. The data used are the global stratospheric geopotential thickness and height analyses which are derived mainly from the Stratospheric Sounding Units (SSUs) on board TIROS-N and NOAA satellites. A clear example of the influence of the normal mode Rossby wave on the mean flow is reported. The mechanism considered is interference between the normal mode Rossby wave and the quasi-stationary wave.

  2. Normal mode extraction and environmental inversion from underwater acoustic data

    NASA Astrophysics Data System (ADS)

    Neilsen, Tracianne Beesley

    2000-11-01

    The normal modes of acoustic propagation in the shallow ocean are extracted from sound recorded on a vertical line array (VLA) of hydrophones as a source travels nearby, and the extracted modes are used to invert for the environmental properties of the ocean. The mode extraction is accomplished by performing a singular value decomposition (SVD) of individual frequency components of the signal's temporally-averaged, spatial cross-spectral density matrix. The SVD produces a matrix containing a mutually orthogonal set of basis functions, which are proportional to the depth-dependent normal modes, and a diagonal matrix containing the singular values, which are proportional to the modal source excitations and mode eigenvalues. The extracted modes exist in the ocean at the time the signal is recorded and thus may be used to estimate the sound speed profile and bottom properties. The inversion scheme iteratively refines the environmental parameters using a Levenberg-Marquardt algorithm such that the modeled modes approach the data- extracted modes Simulations are performed to examine the robustness and practicality of the mode extraction and inversion techniques. Experimental data measured in the Hudson Canyon Area of the New Jersey Shelf are analyzed, and modes are successfully extracted at the frequencies of a towed source. Modes are also extracted from ambient noise recorded on the VLA during the experiment. Using data-extracted modes, inverted values of the water depth, the thickness of a thin first sediment layer, and the compressional sound speed at the top of the first layer are found to be in good agreement with historical values. The density, attenuation, and properties of the second layer are not well determined because the inversion method is only able to obtain reliable values for the parameters that influence the mode shapes in the water column.

  3. Normal modes of prion proteins: from native to infectious particle.

    PubMed

    Samson, Abraham O; Levitt, Michael

    2011-03-29

    Prion proteins (PrP) are the infectious agent in transmissible spongiform encephalopathies (i.e., mad cow disease). To be infectious, prion proteins must undergo a conformational change involving a decrease in α-helical content along with an increase in β-strand content. This conformational change was evaluated by means of elastic normal modes. Elastic normal modes show a diminution of two α-helices by one and two residues, as well as an extension of two β-strands by three residues each, which could instigate the conformational change. The conformational change occurs in a region that is compatible with immunological studies, and it is observed more frequently in mutant prions that are prone to conversion than in wild-type prions because of differences in their starting structures, which are amplified through normal modes. These findings are valuable for our comprehension of the conversion mechanism associated with the conformational change in prion proteins. PMID:21338080

  4. Identification of nonlinear boundary effects using nonlinear normal modes

    NASA Astrophysics Data System (ADS)

    Ahmadian, Hamid; Zamani, Arash

    2009-08-01

    Local nonlinear effects due to micro-slip/slap introduced in boundaries of structures have dominant influence on their lower modal model. This paper studies these effects by experimentally observing the behavior of a clamped-free beam structure with local nonlinearities due to micro-slip at the clamped end. The structure is excited near one of its resonance frequencies and recorded responses are employed to identify the nonlinear effects at the boundary. The nonlinear response of structure is defined using an amplitude-dependent nonlinear normal mode identified from measured responses. A new method for reconstructing nonlinear normal mode is represented in this paper by relating the nonlinear normal mode to the clamped end displacement-dependent stiffness parameters using an eigensensitivity analysis. Solution of obtained equations results equivalent stiffness models at different vibration amplitudes and the corresponding nonlinear normal mode is identified. The approach results nonlinear modes with efficient capabilities in predicting dynamical behavior of the structure at different loading conditions. To evaluate the efficiency of the identified model, the structure is excited at higher excitation load levels than those employed in identification procedures and the observed responses are compared with the predictions of the model at the corresponding input force levels. The predictions are in good agreement with the observed behavior indicating success of identification procedure in capturing the physical merits involve in the boundary local nonlinearities.

  5. Mean flow generation mechanism by inertial waves and normal modes

    NASA Astrophysics Data System (ADS)

    Will, Andreas; Ghasemi, Abouzar

    2016-04-01

    The mean flow generation mechanism by nonlinearity of the inertial normal modes and inertial wave beams in a rotating annular cavity with longitudinally librating walls in stable regime is discussed. Inertial normal modes (standing waves) are excited when libration frequency matches eigenfrequencies of the system. Inertial wave beams are produced by Ekman pumping and suction in a rotating cylinder and form periodic orbits or periodic ray trajectories at selected frequencies. Inertial wave beams emerge as concentrated shear layers in a librating annular cavity, while normal modes appear as global recirculation cells. Both (inertial wave beam and mode) are helical and thus intrinsically non-linear flow structures. No second mode or wave is necessary for non-linearity. We considered the low order normal modes (1,1), (2,1) and (2,2) which are expected to be excited in the planetary objects and investigate the mean flow generation mechanism using two independent solutions: 1) analytical solution (Borcia 2012) and 2) the wave component of the flow (ω0 component) obtained from the direct numerical simulation (DNS). It is well known that a retrograde bulk mean flow is generated by the Ekman boundary layer and E1/4-Stewartson layer close to the outer cylinder side wall due to libration. At and around the normal mode resonant frequencies we found additionally a prograde azimuthal mean flow (Inertial Normal Mode Mean Flow: INMMF) in the bulk of the fluid. The fluid in the bulk is in geostrophic balance in the absence of the inertial normal modes. However, when INMMF is excited, we found that the geostrophic balance does not hold in the region occupied by INMMF. We hypothesize that INMMF is generated by the nonlinearity of the normal modes or by second order effects. Expanding the velocity {V}(u_r,u_θ,u_z) and pressure (p) in a power series in ɛ (libration amplitude), the Navier-Stokes equations are segregated into the linear and nonlinear parts at orders ɛ1 and ɛ^2

  6. Nonlinear normal modes modal interactions and isolated resonance curves

    SciTech Connect

    Kuether, Robert J.; Renson, L.; Detroux, T.; Grappasonni, C.; Kerschen, G.; Allen, M. S.

    2015-05-21

    The objective of the present study is to explore the connection between the nonlinear normal modes of an undamped and unforced nonlinear system and the isolated resonance curves that may appear in the damped response of the forced system. To this end, an energy balance technique is used to predict the amplitude of the harmonic forcing that is necessary to excite a specific nonlinear normal mode. A cantilever beam with a nonlinear spring at its tip serves to illustrate the developments. Furthermore, the practical implications of isolated resonance curves are also discussed by computing the beam response to sine sweep excitations of increasing amplitudes.

  7. Nonlinear normal modes modal interactions and isolated resonance curves

    DOE PAGES

    Kuether, Robert J.; Renson, L.; Detroux, T.; Grappasonni, C.; Kerschen, G.; Allen, M. S.

    2015-05-21

    The objective of the present study is to explore the connection between the nonlinear normal modes of an undamped and unforced nonlinear system and the isolated resonance curves that may appear in the damped response of the forced system. To this end, an energy balance technique is used to predict the amplitude of the harmonic forcing that is necessary to excite a specific nonlinear normal mode. A cantilever beam with a nonlinear spring at its tip serves to illustrate the developments. Furthermore, the practical implications of isolated resonance curves are also discussed by computing the beam response to sine sweepmore » excitations of increasing amplitudes.« less

  8. Modelling secondary microseismic noise by normal mode summation

    NASA Astrophysics Data System (ADS)

    Gualtieri, L.; Stutzmann, E.; Capdeville, Y.; Ardhuin, F.; Schimmel, M.; Mangeney, A.; Morelli, A.

    2013-06-01

    Secondary microseisms recorded by seismic stations are generated in the ocean by the interaction of ocean gravity waves. We present here the theory for modelling secondary microseismic noise by normal mode summation. We show that the noise sources can be modelled by vertical forces and how to derive them from a realistic ocean wave model. We then show how to compute bathymetry excitation effect in a realistic earth model by using normal modes and a comparison with Longuet-Higgins approach. The strongest excitation areas in the oceans depends on the bathymetry and period and are different for each seismic mode. Seismic noise is then modelled by normal mode summation considering varying bathymetry. We derive an attenuation model that enables to fit well the vertical component spectra whatever the station location. We show that the fundamental mode of Rayleigh waves is the dominant signal in seismic noise. There is a discrepancy between real and synthetic spectra on the horizontal components that enables to estimate the amount of Love waves for which a different source mechanism is needed. Finally, we investigate noise generated in all the oceans around Africa and show that most of noise recorded in Algeria (TAM station) is generated in the Northern Atlantic and that there is a seasonal variability of the contribution of each ocean and sea.

  9. User's manual for the coupled mode version of the normal modes rotor aeroelastic analysis computer program

    NASA Technical Reports Server (NTRS)

    Bergquist, R. R.; Carlson, R. G.; Landgrebe, A. J.; Egolf, T. A.

    1974-01-01

    This User's Manual was prepared to provide the engineer with the information required to run the coupled mode version of the Normal Modes Rotor Aeroelastic Analysis Computer Program. The manual provides a full set of instructions for running the program, including calculation of blade modes, calculations of variable induced velocity distribution and the calculation of the time history of the response for either a single blade or a complete rotor with an airframe (the latter with constant inflow).

  10. "Good Vibrations": A workshop on oscillations and normal modes

    NASA Astrophysics Data System (ADS)

    Barbieri, Sara; Carpineti, Marina; Giliberti, Marco; Rigon, Enrico; Stellato, Marco; Tamborini, Marina

    2016-05-01

    We describe some theatrical strategies adopted in a two hour workshop in order to show some meaningful experiments and the underlying useful ideas to describe a secondary school path on oscillations, that develops from harmonic motion to normal modes of oscillations, and makes extensive use of video analysis, data logging, slow motions and applet simulations. Theatre is an extremely useful tool to stimulate motivation starting from positive emotions. That is the reason why the theatrical approach to the presentation of physical themes has been explored by the group "Lo spettacolo della Fisica" (http://spettacolo.fisica.unimi.it) of the Physics Department of University of Milano for the last ten years (Carpineti et al., JCOM, 10 (2011) 1; Nuovo Cimento B, 121 (2006) 901) and has been inserted also in the European FP7 Project TEMI (Teaching Enquiry with Mysteries Incorporated, see http://teachingmysteries.eu/en) which involves 13 different partners coming from 11 European countries, among which the Italian (Milan) group. According to the TEMI guidelines, this workshop has a written script based on emotionally engaging activities of presenting mysteries to be solved while participants have been involved in nice experiments following the developed path.

  11. S-Wave Normal Mode Propagation in Aluminum Cylinders

    USGS Publications Warehouse

    Lee, Myung W.; Waite, William F.

    2010-01-01

    Large amplitude waveform features have been identified in pulse-transmission shear-wave measurements through cylinders that are long relative to the acoustic wavelength. The arrival times and amplitudes of these features do not follow the predicted behavior of well-known bar waves, but instead they appear to propagate with group velocities that increase as the waveform feature's dominant frequency increases. To identify these anomalous features, the wave equation is solved in a cylindrical coordinate system using an infinitely long cylinder with a free surface boundary condition. The solution indicates that large amplitude normal-mode propagations exist. Using the high-frequency approximation of the Bessel function, an approximate dispersion relation is derived. The predicted amplitude and group velocities using the approximate dispersion relation qualitatively agree with measured values at high frequencies, but the exact dispersion relation should be used to analyze normal modes for full ranges of frequency of interest, particularly at lower frequencies.

  12. A High Resolution Normal Mode Solution of Japan Sea

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Satake, K.

    2014-12-01

    Normal mode calculation of a semi-closed or completely closed bay or ocean basin helps us to understand the oscillation characteristics including those excited by incoming tsunamis. In addition, tsunami propagation can be synthesized by superposition of normal modes. Japan Sea is an almost closed ocean basin where many large tsunamigenic earthquakes occurred (fig. 1). Satake and Shimazaki (1988) calculated the normal modes using a 20km grid (~10' or about 2,000 ocean grids), compared the observed and calculated normal modes from the 1964 Niigata and 1983 Japan Sea earthquakes, and discussed the their different excitation characteristics . Because of development of computer and numerical computation techniques, it is worthwhile to revisit this problem. Starting from Laplace's tidal equations and ignoring the rotation of the earth, Loomis (1975) discretized the problem into the eigenvalue problem of a symmetric sparse matrix, which was solved by Householder transformations. This method is used by Satake and Shimazaki (1988) for Japan Sea and Aida (1996) for Tokyo Bay. However, this method needs O(n^3) operation in time and O(n^2) in memory (n is the total number of water grid. e.g., for Japan Sea in 30 sec grid, n~10^6), which would require a super computer.To overcome this disadvantage, we first introduce a recent iteration method called Implicitly Restarted Arnoldi Method (Lehoucq et al., 1997), which itself speeds up the calculation a bit. Then after we develop a sparse version of matrix storage and multiplication, the operation count in time and memory reduced dramatically to O(n^1.5) (including about 0.5 for iteration process) and O(n) respectively, utilizing the special property of the matrix and the iteration method. This means any current computer can easily solve a large eigenvalue problem. Earthquakes.png

  13. Zero Sound Mode in Normal Liquid {sup 3}He

    SciTech Connect

    Albergamo, F.; Verbeni, R.; Huotari, S.; Vanko, G.; Monaco, G.

    2007-11-16

    Inelastic x-ray scattering has been utilized to study the elementary excitations of normal liquid {sup 3}He at the temperature T=1.10{+-}0.05 K and saturated vapor pressure in the wave vector range 0.15{<=}Q{<=}3.15 A{sup -1}. The present data provide direct information on the zero-sound mode in the mesoscopic wave vector range where it was expected to decay into particle-hole excitations. The obtained results show no evidence of such a decay: the zero-sound mode remains well defined in the whole explored wave number range, thus witnessing a continuous transition of the atom dynamics from the collective to the single particle regime similarly to what is usually found in simple liquids.

  14. Modeling secondary microseismic noise by normal mode summation

    NASA Astrophysics Data System (ADS)

    Gualtieri, Lucia; Stutzmann, Eleonore; Capdeville, Yann; Ardhuin, Fabrice; Schimmel, Martin; Mangenay, Anne; Morelli, Andrea

    2013-04-01

    Seismic noise is the continuous oscillation of the ground recorded by seismic stations in the period band 5-20s. In particular, secondary microseisms occur in the period band 5-12s and are generated in the ocean by the interaction of ocean gravity waves. We present the theory for modeling secondary microseismic noise by normal mode summation. We show that the noise sources can be modeled by vertical forces and how to derive them from a realistic ocean wave model. During the computation we take into account the bathymetry. We show how to compute bathymetry excitation effect in a realistic Earth model using normal modes and a comparison with Longuet-Higgins (1950) approach. The strongest excitation areas in the oceans depends on the bathymetry and period and are different for each seismic mode. We derive an attenuation model than enables to fit well the vertical component spectra whatever the station location. We show that the fundamental mode of Rayleigh wave is the dominant signal in seismic noise and it is sufficient to reproduce the main features of noise spectra amplitude. We also model horizontal components. There is a discrepancy between real and synthetic spectra on the horizontal components that enables to estimate the amount of Love waves for which a different source mechanism is needed. Finally, we investigate noise generated in all the oceans around Africa and show that most of noise recorded in Algeria (TAM station) is generated in the Northern Atlantic and that there is a seasonal variability of the contribution of each ocean and sea. Moreover, we also show that the Mediterranean Sea contributes significantly to the short period noise in winter.

  15. The normal modes of lattice vibrations of ice XI

    PubMed Central

    Zhang, Peng; Wang, Zhe; Lu, Ying-Bo; Ding, Zheng-Wen

    2016-01-01

    The vibrational spectrum of ice XI at thermal wavelengths using the CASTEP code, a first-principles simulation method, is investigated. A dual-track approach is constructed to verify the validity for the computational phonon spectrum: collate the simulated spectrum with inelastic neutron scattering experiments and assign the photon scattering peaks according to the calculated normal vibration frequencies. The 33 optical normal vibrations at the Brillouin center are illustrated definitely from the ab initio outcomes. The depolarizing field effect of the hydrogen bond vibrations at frequencies of 229 cm−1 and 310 cm−1 is found to agree well with the LST relationship. It is a convincing evidence to manifest the LO-TO splitting of hydrogen bonds in ice crystal. We attribute the two hydrogen bond peaks to the depolarization effect and apply this viewpoint to ordinary ice phase, ice Ih, which is difficult to analyse their vibration modes due to proton disorder. PMID:27375199

  16. The normal modes of lattice vibrations of ice XI

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Wang, Zhe; Lu, Ying-Bo; Ding, Zheng-Wen

    2016-07-01

    The vibrational spectrum of ice XI at thermal wavelengths using the CASTEP code, a first-principles simulation method, is investigated. A dual-track approach is constructed to verify the validity for the computational phonon spectrum: collate the simulated spectrum with inelastic neutron scattering experiments and assign the photon scattering peaks according to the calculated normal vibration frequencies. The 33 optical normal vibrations at the Brillouin center are illustrated definitely from the ab initio outcomes. The depolarizing field effect of the hydrogen bond vibrations at frequencies of 229 cm‑1 and 310 cm‑1 is found to agree well with the LST relationship. It is a convincing evidence to manifest the LO-TO splitting of hydrogen bonds in ice crystal. We attribute the two hydrogen bond peaks to the depolarization effect and apply this viewpoint to ordinary ice phase, ice Ih, which is difficult to analyse their vibration modes due to proton disorder.

  17. An instantaneous normal mode description of relaxation in supercooled liquids

    NASA Astrophysics Data System (ADS)

    Keyes, T.; Vijayadamodar, G. V.; Zurcher, U.

    1997-03-01

    Relaxation in supercooled liquids is formulated from the instantaneous normal modes (INM) point of view. The frequency and temperature dependence of the unstable, imaginary frequency lobe of the INM density of states, <ρu(ω,T)> (for simplicity we write ω instead of iω), is investigated and characterized over a broad temperature range, 10⩾T⩾0.42, in the unit density Lennard-Jones liquid. INM theories of diffusion invoke Im-ω modes descriptive of barrier crossing, but not all imaginary frequency modes fall into this category. There exists a cutoff frequency ωc such that modes with ω<ωc correspond to "shoulder potentials," whereas the potential profiles include barrier-crossing double wells for ω>ωc. Given that only modes with ω>ωc contribute to diffusion, the barrier crossing rate, ωh, and the self diffusion constant D, are shown to be proportional to the density of states evaluated at the cutoff frequency, <ρu(ωc,T)>. The density of states exhibits crossover behavior in its temperature dependence such that the exponential T-dependence of D(T) crosses over from Zwanzig-Bassler exp(-E2/T2) behavior at low T to Arrhenius exp(-E/T) behavior at high T; the exponential may be too weak to be observed, in which case D(T) is a power law. Based on the properties of LJ, a general INM description of strong and fragile liquids is presented, with a physical interpretation in terms of the "landscape" of the potential energy surface.

  18. Normal Modes in Rotation of Two/Three Layers Planets

    NASA Astrophysics Data System (ADS)

    Gusev, A.; Petrova, N.; Kitiashvili, I.

    2006-08-01

    In many theoretical investigations the normal modes of the linearized equations of rotation are computed, yielding both the periods and the eigenspaces of three librations. The modern view of internal structure of the planet takes into account a complex two- or three-layer model. For a planet with a solid inner core and a liquid outer core, there are four rotational normal modes. This numbers is reduced to two for a planet without inner core, and to one for a planet without liquid core. All types of modes are result of non-coincidence of rotation axes and of the main inertia moments of mantle, outer and inner core. For the Earth and the nearest planets - Mars and Moon - there is a wide spectrum of observations and theoretical speculations about parameters of the planet's deep interior. For instance, the most interesting data on dynamics and internal structure of the Moon are already accumulated as a result of the different observations and space experiments. The Japanese space experiments Lunar A, SELENE-missions, Luna Glob (Russia) planed for 2007 - 2012 years will contribute significantly to the information about the Moon: qualitative parameter Q, Love number k[2], core's radius R[c], core's density etc. In a case of free rotation of the two- or three-layer planet the two or four modes in its polar motion might be observed. The evaluations of the periods were made: periods of the Free Core Nutation (FCN) were obtained for Mercury (P[FCN] = 597 yrs) and first time for Venus (P[FCN] = 1534 yrs). For the Moon the period of Free Inner Core Nutation (FICN) P[FICN]= 515 - 634 yrs and the period of Inner Core Wobble (ICW) P[ICW]= 101 - 108 yrs were computed for different models of the lunar core. The main tendency of behavior of two new periods (P [FICN ]and P[ICW]) is preliminary revealed: a) the FICN-period decreases both with the increasing of the core's radius and of the thick of fluid shell; b) conversely, the ICW-period have the direct ratio to radius of a core

  19. [Raman, FTIR spectra and normal mode analysis of acetanilide].

    PubMed

    Liang, Hui-Qin; Tao, Ya-Ping; Han, Li-Gang; Han, Yun-Xia; Mo, Yu-Jun

    2012-10-01

    The Raman and FTIR spectra of acetanilide (ACN) were measured experimentally in the regions of 3 500-50 and 3 500-600 cm(-1) respectively. The equilibrium geometry and vibration frequencies of ACN were calculated based on density functional theory (DFT) method (B3LYP/6-311G(d, p)). The results showed that the theoretical calculation of molecular structure parameters are in good agreement with previous report and better than the ones calculated based on 6-31G(d), and the calculated frequencies agree well with the experimental ones. Potential energy distribution of each frequency was worked out by normal mode analysis, and based on this, a detailed and accurate vibration frequency assignment of ACN was obtained. PMID:23285870

  20. Generalized theory of helicon waves. I. Normal modes

    SciTech Connect

    Chen, F.F.; Arnush, D.

    1997-09-01

    The theory of helicon waves is extended to include finite electron mass. This introduces an additional branch to the dispersion relation that is essentially an electron cyclotron or Trivelpiece{endash}Gould (TG) wave with a short radial wavelength. The effect of the TG wave is expected to be important only for low dc magnetic fields and long parallel wavelengths. The normal modes at low fields are mixtures of the TG wave and the usual helicon wave and depend on the nature of the boundaries. Computations show, however, that since the TG waves are damped near the surface of the plasma, the helicon wave at high fields is almost exactly the same as is found when the electron mass is neglected. {copyright} {ital 1997 American Institute of Physics.}

  1. Vibrational dynamics of vocal folds using nonlinear normal modes.

    PubMed

    Pinheiro, Alan P; Kerschen, Gaëtan

    2013-08-01

    Many previous works involving physical models, excised and in vivo larynges have pointed out nonlinear vibration in vocal folds during voice production. Moreover, theoretical studies involving mechanical modeling of these folds have tried to gain a profound understanding of the observed nonlinear phenomena. In this context, the present work uses the nonlinear normal mode theory to investigate the nonlinear modal behavior of 16 subjects using a two-mass mechanical modeling of the vocal folds. The free response of the conservative system at different energy levels is considered to assess the impact of the structural nonlinearity of the vocal fold tissues. The results show very interesting and complex nonlinear phenomena including frequency-energy dependence, subharmonic regimes and, in some cases, modal interactions, entrainment and bifurcations. PMID:23218815

  2. Hybrid Electron Microscopy Normal Mode Analysis graphical interface and protocol.

    PubMed

    Sorzano, Carlos Oscar S; de la Rosa-Trevín, José Miguel; Tama, Florence; Jonić, Slavica

    2014-11-01

    This article presents an integral graphical interface to the Hybrid Electron Microscopy Normal Mode Analysis (HEMNMA) approach that was developed for capturing continuous motions of large macromolecular complexes from single-particle EM images. HEMNMA was shown to be a good approach to analyze multiple conformations of a macromolecular complex but it could not be widely used in the EM field due to a lack of an integral interface. In particular, its use required switching among different software sources as well as selecting modes for image analysis was difficult without the graphical interface. The graphical interface was thus developed to simplify the practical use of HEMNMA. It is implemented in the open-source software package Xmipp 3.1 (http://xmipp.cnb.csic.es) and only a small part of it relies on MATLAB that is accessible through the main interface. Such integration provides the user with an easy way to perform the analysis of macromolecular dynamics and forms a direct connection to the single-particle reconstruction process. A step-by-step HEMNMA protocol with the graphical interface is given in full details in Supplementary material. The graphical interface will be useful to experimentalists who are interested in studies of continuous conformational changes of macromolecular complexes beyond the modeling of continuous heterogeneity in single particle reconstruction.

  3. Revealing short-period normal modes of the atmosphere

    NASA Astrophysics Data System (ADS)

    Shved, G. M.; Ermolenko, S. I.; Hoffmann, P.

    2015-09-01

    Barometer and seismometer measurements at Collm, Germany (51.3° N, 13.0° E) for all of 2002 are used to search for atmospheric normal modes (ANMs) in the frequency range 50-310 µHz. The measurements are spectrally analyzed using a 5-day window sliding along the 1-year series with a 1-day step. The subsequent analysis follows two procedures: (a) revealing features in the frequency distribution of the number of statistically significant spectral peaks in histograms built on the basis of these spectra and (b) calculating the multiplication spectra for the raw spectra. The two procedures yield the same result for the two instruments, i.e., reveal a periodicity in the clustering of atmospheric modes on the frequency axis with a period of ˜6 µHz. The fact that this period is close to 7 μHz, which is predicted by the crude theory of gravity—inertia ANMs [3] for their frequency distribution, suggests that ANMs are generated down to as small a period as ˜1 h.

  4. Adaptive Batch Mode Active Learning.

    PubMed

    Chakraborty, Shayok; Balasubramanian, Vineeth; Panchanathan, Sethuraman

    2015-08-01

    Active learning techniques have gained popularity to reduce human effort in labeling data instances for inducing a classifier. When faced with large amounts of unlabeled data, such algorithms automatically identify the exemplar and representative instances to be selected for manual annotation. More recently, there have been attempts toward a batch mode form of active learning, where a batch of data points is simultaneously selected from an unlabeled set. Real-world applications require adaptive approaches for batch selection in active learning, depending on the complexity of the data stream in question. However, the existing work in this field has primarily focused on static or heuristic batch size selection. In this paper, we propose two novel optimization-based frameworks for adaptive batch mode active learning (BMAL), where the batch size as well as the selection criteria are combined in a single formulation. We exploit gradient-descent-based optimization strategies as well as properties of submodular functions to derive the adaptive BMAL algorithms. The solution procedures have the same computational complexity as existing state-of-the-art static BMAL techniques. Our empirical results on the widely used VidTIMIT and the mobile biometric (MOBIO) data sets portray the efficacy of the proposed frameworks and also certify the potential of these approaches in being used for real-world biometric recognition applications.

  5. Photoelectron spectra of dihalomethyl anions: Testing the limits of normal mode analysis

    NASA Astrophysics Data System (ADS)

    Vogelhuber, Kristen M.; Wren, Scott W.; McCoy, Anne B.; Ervin, Kent M.; Lineberger, W. Carl

    2011-05-01

    We report the 364-nm negative ion photoelectron spectra of CHX2- and CDX2-, where X = Cl, Br, and I. The pyramidal dihalomethyl anions undergo a large geometry change upon electron photodetachment to become nearly planar, resulting in multiple extended vibrational progressions in the photoelectron spectra. The normal mode analysis that successfully models photoelectron spectra when geometry changes are modest is unable to reproduce qualitatively the experimental data using physically reasonable parameters. Specifically, the harmonic normal mode analysis using Cartesian displacement coordinates results in much more C-H stretch excitation than is observed, leading to a simulated photoelectron spectrum that is much broader than that which is seen experimentally. A (2 + 1)-dimensional anharmonic coupled-mode analysis much better reproduces the observed vibrational structure. We obtain an estimate of the adiabatic electron affinity of each dihalomethyl radical studied. The electron affinity of CHCl2 and CDCl2 is 1.3(2) eV, of CHBr2 and CDBr2 is 1.9(2) eV, and of CHI2 and CDI2 is 1.9(2) eV. Analysis of the experimental spectra illustrates the limits of the conventional normal mode approach and shows the type of analysis required for substantial geometry changes when multiple modes are active upon photodetachment.

  6. Pulse Shaping and Evolution in Normal-Dispersion Mode-Locked Fiber Lasers.

    PubMed

    Renninger, William H; Chong, Andy; Wise, Frank W

    2012-01-01

    Fiber lasers mode locked with large normal group-velocity dispersion have recently achieved femtosecond pulse durations with energies and peak powers at least an order of magnitude greater than those of prior approaches. Several new mode-locking regimes have been demonstrated, including self-similar pulse propagation in passive and active fibers, dissipative solitons, and a pulse evolution that avoids wave breaking at high peak power but has not been reproduced by theoretical treatment. Here, we illustrate the main features of these new pulse-shaping mechanisms through the results of numerical simulations that agree with experimental results. We describe the features that distinguish each new mode-locking state and explain how the interplay of basic processes in the fiber produces the balance of amplitude and phase evolutions needed for stable high-energy pulses. Dissipative processes such as spectral filtering play a major role in normal-dispersion mode locking. Understanding the different mechanisms allows us to compare and contrast them, as well as to categorize them to some extent.

  7. Pulse Shaping and Evolution in Normal-Dispersion Mode-Locked Fiber Lasers

    PubMed Central

    Renninger, William H.; Chong, Andy; Wise, Frank W.

    2012-01-01

    Fiber lasers mode locked with large normal group-velocity dispersion have recently achieved femtosecond pulse durations with energies and peak powers at least an order of magnitude greater than those of prior approaches. Several new mode-locking regimes have been demonstrated, including self-similar pulse propagation in passive and active fibers, dissipative solitons, and a pulse evolution that avoids wave breaking at high peak power but has not been reproduced by theoretical treatment. Here, we illustrate the main features of these new pulse-shaping mechanisms through the results of numerical simulations that agree with experimental results. We describe the features that distinguish each new mode-locking state and explain how the interplay of basic processes in the fiber produces the balance of amplitude and phase evolutions needed for stable high-energy pulses. Dissipative processes such as spectral filtering play a major role in normal-dispersion mode locking. Understanding the different mechanisms allows us to compare and contrast them, as well as to categorize them to some extent. PMID:22899881

  8. RAMVIB: a new flexible normal mode analysis software package for biological spectroscopists

    NASA Astrophysics Data System (ADS)

    Fraczkiewicz, Robert; Czernuszewicz, Roman S.

    1997-11-01

    A new package of computer programs called RAMVIB and designed to perform normal mode calculations is described. In our experience, RAMVIB has been proven useful in theoretical interpretation of resonance Raman spectra of metalloprotein active sites and their model complexes. It differs from existing programs in many aspects. The new and powerful vibrational force field optimization technique used in RAMVIB is free of singularity and regularization error problems. An arbitrary subset of force constants can be refined simultaneously for any collection of related molecules. A set of diagnostic programs tests quality and condition of input matrices. A thorough force constant selection can be performed based on several independent criteria. Coordinate redundancies are automatically removed by our new algorithm. Similarly, normal modes for different isotopomers are sorted and matched automatically. The flexibility of RAMVIB coming from its modular character makes it easily adjustable to solve a number of other problems related to normal mode analysis, e.g. calculation of scaling factors of ab initio derived harmonic force fields.

  9. Comparative Investigation of Normal Modes and Molecular Dynamics of Hepatitis C NS5B Protein

    NASA Astrophysics Data System (ADS)

    Asafi, M. S.; Yildirim, A.; Tekpinar, M.

    2016-04-01

    Understanding dynamics of proteins has many practical implications in terms of finding a cure for many protein related diseases. Normal mode analysis and molecular dynamics methods are widely used physics-based computational methods for investigating dynamics of proteins. In this work, we studied dynamics of Hepatitis C NS5B protein with molecular dynamics and normal mode analysis. Principal components obtained from a 100 nanoseconds molecular dynamics simulation show good overlaps with normal modes calculated with a coarse-grained elastic network model. Coarse-grained normal mode analysis takes at least an order of magnitude shorter time. Encouraged by this good overlaps and short computation times, we analyzed further low frequency normal modes of Hepatitis C NS5B. Motion directions and average spatial fluctuations have been analyzed in detail. Finally, biological implications of these motions in drug design efforts against Hepatitis C infections have been elaborated.

  10. Black-hole normal modes: A WKB approach. IV. Kerr black holes

    NASA Astrophysics Data System (ADS)

    Seidel, Edward; Iyer, Sai

    1990-01-01

    Using the higher-order WKB method developed by Iyer and Will, we have computed the low-lying normal modes of Kerr black holes for both scalar and gravitational perturbations. For the gravitational modes, we compare our results to previously published numerical results. For some of these modes, we find agreement to within 1% for both the real and imaginary parts of the normal-mode frequency over a wide range of values for the rotation parameter a of the black hole. For other modes, good agreement is limited to lower values of a. The difficulties of the method for higher values of the rotation parameter are discussed.

  11. Prufer Transformations for the Normal Modes in Ocean Acoustics

    SciTech Connect

    Baggeroer, Arthur B.

    2010-09-06

    In 1926 Prufer introduced a method of transforming the second order Sturm-Liouville (SL) equation into two nonlinear first order differential equations for the phase oe and ''magnitude'', |oe{sup 2}+oe{sup 2}| for a Poincare phase space representation, (oe,oe). The useful property is the phase equation decouples from the magnitude one which leads to a nonlinear, two point boundary value problem for the eigenvalues, or SL numbers. The transformation has been used both theoretically, e.g. Atkinson, [1960] to prove certain properties of SL equations as well as numerically e.g Bailey [1978]. This paper examines the utility of the Prufer transformation in the context of numerical solutions for modes of the ocean acoustic wave equation. (Its use is certainly not well known in the ocean acoustics community.) Equations for the phase, oe, and natural logarithm of the ''magnitude'', ln(|oe{sup 2}+oe{sup 2}|) lead to same decoupling and a fast and efficient numerical solution with the SL eigenvalues mapping to the horizontal wavenubers. The Prufer transformation has stabilty problems for low order modes at high frequecies, so a numerically stable method of integrating the phase equation is derived. This seems to be the first time the these stability issues have been highlighted to provide a robust algorthim for the modes.

  12. Hypnotic induction decreases anterior default mode activity.

    PubMed

    McGeown, William J; Mazzoni, Giuliana; Venneri, Annalena; Kirsch, Irving

    2009-12-01

    The 'default mode' network refers to cortical areas that are active in the absence of goal-directed activity. In previous studies, decreased activity in the 'default mode' has always been associated with increased activation in task-relevant areas. We show that the induction of hypnosis can reduce anterior default mode activity during rest without increasing activity in other cortical regions. We assessed brain activation patterns of high and low suggestible people while resting in the fMRI scanner and while engaged in visual tasks, in and out of hypnosis. High suggestible participants in hypnosis showed decreased brain activity in the anterior parts of the default mode circuit. In low suggestible people, hypnotic induction produced no detectable changes in these regions, but instead deactivated areas involved in alertness. The findings indicate that hypnotic induction creates a distinctive and unique pattern of brain activation in highly suggestible subjects. PMID:19782614

  13. High-overtone black-hole normal modes: A WKB contour-integral approach

    NASA Astrophysics Data System (ADS)

    Guinn, James Williams

    When black holes are perturbed by external sources, they oscillate, or ring, at discrete frequencies corresponding to a set of quasi-normal modes. Gravitational perturbations of the surrounding space-time, as well as 'test' perturbations of electromagnetic and scalar fields in a black hole background space-time, lead to normal modes. In all three cases, the perturbation equations can be reduced to a single Schroedinger-like equation in 1-D, which treats the three types of responses as mathematically equivalent to tunneling of quantum mechanical waves through a potential barrier. Normal modes correspond to tunneling transmission resonances. A high order Wentzel-Kramers-Brillouin (WKB) contour integral technique is shown to apply to the problem of black hole normal modes, first by studying tunneling and normal modes of a model potential barrier, the Poeschl-Teller potential, and then by comparing the contour integral technique with a method derived by Iyer and Will for tunneling near the peak of general potential barriers, which accurately describe low overtone black hole normal modes. The contour WKB technique is then applied to the high overtone normal modes. Results are compared to other techniques.

  14. Echoes from anharmonic normal modes in model glasses.

    PubMed

    Burton, Justin C; Nagel, Sidney R

    2016-03-01

    Glasses display a wide array of nonlinear acoustic phenomena at temperatures T ≲ 1 K. This behavior has traditionally been explained by an ensemble of weakly coupled, two-level tunneling states, a theory that is also used to describe the thermodynamic properties of glasses at low temperatures. One of the most striking acoustic signatures in this regime is the existence of phonon echoes, a feature that has been associated with two-level systems with the same formalism as spin echoes in NMR. Here we report the existence of a distinctly different type of acoustic echo in classical models of glassy materials. Our simulations consist of finite-ranged, repulsive spheres and also particles with attractive forces using Lennard-Jones interactions. We show that these echoes are due to anharmonic, weakly coupled vibrational modes and perhaps provide an alternative explanation for the phonon echoes observed in glasses at low temperatures. PMID:27078434

  15. Echoes from anharmonic normal modes in model glasses.

    PubMed

    Burton, Justin C; Nagel, Sidney R

    2016-03-01

    Glasses display a wide array of nonlinear acoustic phenomena at temperatures T ≲ 1 K. This behavior has traditionally been explained by an ensemble of weakly coupled, two-level tunneling states, a theory that is also used to describe the thermodynamic properties of glasses at low temperatures. One of the most striking acoustic signatures in this regime is the existence of phonon echoes, a feature that has been associated with two-level systems with the same formalism as spin echoes in NMR. Here we report the existence of a distinctly different type of acoustic echo in classical models of glassy materials. Our simulations consist of finite-ranged, repulsive spheres and also particles with attractive forces using Lennard-Jones interactions. We show that these echoes are due to anharmonic, weakly coupled vibrational modes and perhaps provide an alternative explanation for the phonon echoes observed in glasses at low temperatures.

  16. Electromagnetic fluctuations and normal modes of a drifting relativistic plasma

    SciTech Connect

    Ruyer, C.; Gremillet, L.; Bénisti, D.; Bonnaud, G.

    2013-11-15

    We present an exact calculation of the power spectrum of the electromagnetic fluctuations in a relativistic equilibrium plasma described by Maxwell-Jüttner distribution functions. We consider the cases of wave vectors parallel or normal to the plasma mean velocity. The relative contributions of the subluminal and supraluminal fluctuations are evaluated. Analytical expressions of the spatial fluctuation spectra are derived in each case. These theoretical results are compared to particle-in-cell simulations, showing a good reproduction of the subluminal fluctuation spectra.

  17. SwarmDock and the Use of Normal Modes in Protein-Protein Docking

    PubMed Central

    Moal, Iain H.; Bates, Paul A.

    2010-01-01

    Here is presented an investigation of the use of normal modes in protein-protein docking, both in theory and in practice. Upper limits of the ability of normal modes to capture the unbound to bound conformational change are calculated on a large test set, with particular focus on the binding interface, the subset of residues from which the binding energy is calculated. Further, the SwarmDock algorithm is presented, to demonstrate that the modelling of conformational change as a linear combination of normal modes is an effective method of modelling flexibility in protein-protein docking. PMID:21152290

  18. The effect of small-scale structure on normal mode frequencies and global inversions

    NASA Astrophysics Data System (ADS)

    Snieder, Roel; Beckers, Jos; Neele, Filip

    1991-01-01

    A model of all the subduction zones and spreading ridges of the earth's upper mantle is used for the purpose of computing normal-mode frequency shifts for an earth model that contains significant small-scale structure. The model is detailed, and a short outline of the employed scattering theory is given. The normal-mode frequency shifts are shown, and inversions for a global earth model using the synthetic normal-mode frequency shifts are presented. The earth model in this inversion is presented as a truncated series of spherical harmonics, and a comparison is made with the true projection of structure on the same low-order spherical harmonics.

  19. An efficient and numerically stable procedure for generating sextic force fields in normal mode coordinates.

    PubMed

    Sibaev, M; Crittenden, D L

    2016-06-01

    In this paper, we outline a general, scalable, and black-box approach for calculating high-order strongly coupled force fields in rectilinear normal mode coordinates, based upon constructing low order expansions in curvilinear coordinates with naturally limited mode-mode coupling, and then transforming between coordinate sets analytically. The optimal balance between accuracy and efficiency is achieved by transforming from 3 mode representation quartic force fields in curvilinear normal mode coordinates to 4 mode representation sextic force fields in rectilinear normal modes. Using this reduced mode-representation strategy introduces an error of only 1 cm(-1) in fundamental frequencies, on average, across a sizable test set of molecules. We demonstrate that if it is feasible to generate an initial semi-quartic force field in curvilinear normal mode coordinates from ab initio data, then the subsequent coordinate transformation procedure will be relatively fast with modest memory demands. This procedure facilitates solving the nuclear vibrational problem, as all required integrals can be evaluated analytically. Our coordinate transformation code is implemented within the extensible PyPES library program package, at http://sourceforge.net/projects/pypes-lib-ext/. PMID:27276945

  20. An efficient and numerically stable procedure for generating sextic force fields in normal mode coordinates.

    PubMed

    Sibaev, M; Crittenden, D L

    2016-06-01

    In this paper, we outline a general, scalable, and black-box approach for calculating high-order strongly coupled force fields in rectilinear normal mode coordinates, based upon constructing low order expansions in curvilinear coordinates with naturally limited mode-mode coupling, and then transforming between coordinate sets analytically. The optimal balance between accuracy and efficiency is achieved by transforming from 3 mode representation quartic force fields in curvilinear normal mode coordinates to 4 mode representation sextic force fields in rectilinear normal modes. Using this reduced mode-representation strategy introduces an error of only 1 cm(-1) in fundamental frequencies, on average, across a sizable test set of molecules. We demonstrate that if it is feasible to generate an initial semi-quartic force field in curvilinear normal mode coordinates from ab initio data, then the subsequent coordinate transformation procedure will be relatively fast with modest memory demands. This procedure facilitates solving the nuclear vibrational problem, as all required integrals can be evaluated analytically. Our coordinate transformation code is implemented within the extensible PyPES library program package, at http://sourceforge.net/projects/pypes-lib-ext/.

  1. Conformational Equilibrium of CDK/Cyclin Complexes by Molecular Dynamics with Excited Normal Modes

    PubMed Central

    Floquet, Nicolas; Costa, Mauricio G.S.; Batista, Paulo R.; Renault, Pedro; Bisch, Paulo M.; Raussin, Florent; Martinez, Jean; Morris, May C.; Perahia, David

    2015-01-01

    Cyclin-dependent kinases (CDKs) and their associated regulatory cyclins are central for timely regulation of cell-cycle progression. They constitute attractive pharmacological targets for development of anticancer therapeutics, since they are frequently deregulated in human cancers and contribute to sustained, uncontrolled tumor proliferation. Characterization of their structural/dynamic features is essential to gain in-depth insight into structure-activity relationships. In addition, the identification of druggable pockets or key intermediate conformations yields potential targets for the development of novel classes of inhibitors. Structural studies of CDK2/cyclin A have provided a wealth of information concerning monomeric/heterodimeric forms of this kinase. There is, however, much less structural information for other CDK/cyclin complexes, including CDK4/cyclin D1, which displays an alternative (open) position of the cyclin partner relative to CDK, contrasting with the closed CDK2/cyclin A conformation. In this study, we carried out normal-mode analysis and enhanced sampling simulations with our recently developed method, molecular dynamics with excited normal modes, to understand the conformational equilibrium on these complexes. Interestingly, the lowest-frequency normal mode computed for each complex described the transition between the open and closed conformations. Exploration of these motions with an explicit-solvent representation using molecular dynamics with excited normal modes confirmed that the closed conformation is the most stable for the CDK2/cyclin A complex, in agreement with their experimentally available structures. On the other hand, we clearly show that an open↔closed equilibrium may exist in CDK4/cyclin D1, with closed conformations resembling that captured for CDK2/cyclin A. Such conformational preferences may result from the distinct distributions of frustrated contacts in each complex. Using the same approach, the putative roles of

  2. On the sensitivity of protein data bank normal mode analysis: an application to GH10 xylanases

    NASA Astrophysics Data System (ADS)

    Tirion, Monique M.

    2015-12-01

    Protein data bank entries obtain distinct, reproducible flexibility characteristics determined by normal mode analyses of their three dimensional coordinate files. We study the effectiveness and sensitivity of this technique by analyzing the results on one class of glycosidases: family 10 xylanases. A conserved tryptophan that appears to affect access to the active site can be in one of two conformations according to x-ray crystallographic electron density data. The two alternate orientations of this active site tryptophan lead to distinct flexibility spectra, with one orientation thwarting the oscillations seen in the other. The particular orientation of this sidechain furthermore affects the appearance of the motility of a distant, C terminal region we term the mallet. The mallet region is known to separate members of this family of enzymes into two classes.

  3. Active control of multiple resistive wall modes

    NASA Astrophysics Data System (ADS)

    Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Bolzonella, T.; Cecconello, M.; Drake, J. R.; Kuldkepp, M.; Manduchi, G.; Marchiori, G.; Marrelli, L.; Martin, P.; Menmuir, S.; Ortolani, S.; Rachlew, E.; Spizzo, G.; Zanca, P.

    2005-12-01

    A two-dimensional array of saddle coils at Mc poloidal and Nc toroidal positions is used on the EXTRAP T2R reversed-field pinch (Brunsell P R et al 2001 Plasma Phys. Control. Fusion 43 1457) to study active control of resistive wall modes (RWMs). Spontaneous growth of several RWMs with poloidal mode number m = 1 and different toroidal mode number n is observed experimentally, in agreement with linear MHD modelling. The measured plasma response to a controlled coil field and the plasma response computed using the linear circular cylinder MHD model are in quantitive agreement. Feedback control introduces a linear coupling of modes with toroidal mode numbers n, n' that fulfil the condition |n - n'| = Nc. Pairs of coupled unstable RWMs are present in feedback experiments with an array of Mc × Nc = 4 × 16 coils. Using intelligent shell feedback, the coupled modes are generally not controlled even though the field is suppressed at the active coils. A better suppression of coupled modes may be achieved in the case of rotating modes by using the mode control feedback scheme with individually set complex gains. In feedback with a larger array of Mc × Nc = 4 × 32 coils, the coupling effect largely disappears, and with this array, the main internal RWMs n = -11, -10, +5, +6 are all simultaneously suppressed throughout the discharge (7 8 wall times). With feedback there is a two-fold extension of the pulse length, compared to discharges without feedback.

  4. FrOsT: A new generation of normal mode seismology

    NASA Astrophysics Data System (ADS)

    Valentine, Andrew; Al-Attar, David; Trampert, Jeannot; Woodhouse, John

    2015-04-01

    Normal mode seismology provides important constraints on earth structure, particularly at the largest spatial scales, and enables the imaging of density heterogeneities within the Earth. In addition, computational approaches built upon normal modes offer an efficient route towards obtaining synthetic seismograms and their sensitivity kernels (partial derivatives of the seismograms with respect to source or structural model parameters). At present, it is difficult to compute normal modes at frequencies higher than around 100 mHz, and'as far as we are aware'no publicly-released codes can perform complete calculations in 3D earth models. However, these are software limitations, rather than inherent problems with the normal modes framework. We are therefore developing the Free Oscillation Toolkit (FrOsT), a suite of software for normal mode seismology designed to enable calculations for arbitrary 3D earth models, and to arbitrarily high frequencies. All codes will be released on an open-source basis in due course. We demonstrate that improved radial integration and mode-counting techniques enable stable calculations at high frequency, and present initial benchmarks in 1D earth models. Through the use of the generalised spherical harmonic formalism, we show that it is straightforward to obtain strain and rotation seismograms, in addition to displacement fields, enabling a full range of data to be handled simultaneously. Finally, we provide an overview of expected future developments, including software to compute complete seismograms in 3D models through full mode coupling.

  5. Computational aspects of the nonlinear normal mode initialization of the GLAS 4th order GCM

    NASA Technical Reports Server (NTRS)

    Navon, I. M.; Bloom, S. C.; Takacs, L.

    1984-01-01

    Using the normal modes of the GLAS 4th Order Model, a Machenhauer nonlinear normal mode initialization (NLNMI) was carried out for the external vertical mode using the GLAS 4th Order shallow water equations model for an equivalent depth corresponding to that associated with the external vertical mode. A simple procedure was devised which was directed at identifying computational modes by following the rate of increase of BAL sub M, the partial (with respect to the zonal wavenumber m) sum of squares of the time change of the normal mode coefficients (for fixed vertical mode index) varying over the latitude index L of symmetric or antisymmetric gravity waves. A working algorithm is presented which speeds up the convergence of the iterative Machenhauer NLNMI. A 24 h integration using the NLNMI state was carried out using both Matsuno and leap-frog time-integration schemes; these runs were then compared to a 24 h integration starting from a non-initialized state. The maximal impact of the nonlinear normal mode initialization was found to occur 6-10 hours after the initial time.

  6. Investigation and Analysis of Current Writing Teaching Mode among English Majors in Normal Universities in China

    ERIC Educational Resources Information Center

    Zeng, Hang-li

    2010-01-01

    This paper has made an investigation on the current writing teaching mode among English majors in normal universities in China, by means of questionnaire, interview and class observation. The study finds out that the current writing teaching mode is not purely product approach or process approach. In fact, the two approaches to writing co-exist in…

  7. Position-independent normal-mode splitting in cavities filled with zero-index metamaterials.

    PubMed

    Jiang, Hai-Tao; Xu, Xiao-Hu; Wang, Zi-Li; Li, Yun-Hui; Yi, Yasha; Chen, Hong

    2012-03-12

    We study the normal-mode splitting when an oscillator is placed in a two-dimensional photonic crystal microcavity embedded with an impedance-matched or an impedance-mismatched zero-index medium (ZIM). Because of the (nearly) uniform localized fields in the ZIM, the normal-mode splitting remains (almost) invariant no matter where the oscillator is. When a split ring resonator is coupled to a transmission-line- based effective ZIM at various locations, nearly position-independent mode splitting is observed. PMID:22418516

  8. Flexural vibrations of a rectangular plate for the lower normal modes

    NASA Astrophysics Data System (ADS)

    Manzanares-Martínez, B.; Flores, J.; Gutiérrez, L.; Méndez-Sánchez, R. A.; Monsivais, G.; Morales, A.; Ramos-Mendieta, F.

    2010-11-01

    Theoretical and experimental results for flexural waves of a rectangular plate with free ends are obtained. Both the natural frequencies and mode shapes are analyzed for the lower normal modes. To take into account the boundary conditions, a plane wave expansion method is used to solve the thin plate theory also known as the 2D Kirchhoff-Love equation. The excitation and detection of the normal modes of the out-of-plane waves are performed using non-contact electromagnetic-acoustic transducers. We conclude that this experimental technique is highly reliable due to the good agreement between theory and experiment.

  9. Normal modes in an overmoded circular waveguide coated with lossy material

    NASA Technical Reports Server (NTRS)

    Lee, C. S.; Lee, S. W.; Chuang, S. L.

    1985-01-01

    The normal modes in an overmoded waveguide coated with a lossy material are analyzed, particularly for their attenuation properties as a function of coating material, layer thickness, and frequency. When the coating material is not too lossy, the low-order modes are highly attenuated even with a thin layer of coating. This coated guide serves as a mode suppressor of the low-order modes, which can be particularly useful for reducing the radar cross section (RCS) of a cavity structure such as a jet inlet. When the coating material is very lossy, low-order modes fall into two distinct groups: highly and lowly attenuated modes. However, as a/lambda (a = radius of the cylinder; lambda = the free-space wavelength) increases, the separation between these two groups becomes less distinctive. The attenuation constants of most of the low-order modes become small, and decrease as a function of lambda sup 2/a sup 3.

  10. A Study of Saturn's Normal Mode Oscillations and Their Forcing of Density Waves in the Rings

    NASA Astrophysics Data System (ADS)

    Friedson, Andrew James; Cao, Lyra

    2016-10-01

    Analysis of Cassini Visual and Infrared Mapping Spectrometer (VIMS) ring occultation profiles has revealed the presence of spiral density waves in Saturn's C ring that are consistent with being driven by gravitational perturbations associated with normal-mode oscillations of the planet [1]. These waves allow the C ring to serve as a sort of seismometer, since their pattern speeds (i.e., azimuthal phase speeds) can in principle be mapped onto the frequencies of the predominant normal oscillations of the planet. The resonant mode frequencies in turn are sensitive to Saturn's internal structure and rotational state. Characterization of the normal modes responsible for the forcing holds the potential to supply important new constraints on Saturn's internal structure and rotation. We perform numerical calculations to determine the resonant frequencies of the normal modes of a uniformly rotating planet for various assumptions regarding its internal stratification and compare the implied pattern speeds to those of density waves observed in the C ring. A question of particular interest that we address is whether quasi-toroidal modes are responsible for exciting a mysterious class of slowly propagating density waves in the ring. We also explore the implications of avoided crossings between modes for explaining observed fine splitting in the pattern speeds of spiral density waves having the same number of spiral arms, and weigh the role that convective overstability may play in exciting large-scale quasi-toroidal modes in Saturn. [1] Hedman, M.M. and Nicholson, P.D. 2014. MNRAS 444, 1369.

  11. Normal modes of the world's oceans: A numerical investigation using Proudman functions

    NASA Technical Reports Server (NTRS)

    Sanchez, Braulio V.; Morrow, Dennis

    1993-01-01

    The numerical modeling of the normal modes of the global oceans is addressed. The results of such modeling could be expected to serve as a guide in the analysis of observations and measurements intended to detect these modes. The numerical computation of normal modes of the global oceans is a field in which several investigations have obtained results during the past 15 years. The results seem to be model-dependent to an unsatisfactory extent. Some modeling areas, such as higher resolution of the bathymetry, inclusion of self-attraction and loading, the role of the Arctic Ocean, and systematic testing by means of diagnostic models are addressed. The results show that the present state of the art is such that a final solution to the normal mode problem still lies in the future. The numerical experiments show where some of the difficulties are and give some insight as to how to proceed in the future.

  12. Vertical normal modes of human ears: Individual variation and frequency estimation from pinna anthropometry.

    PubMed

    Mokhtari, Parham; Takemoto, Hironori; Nishimura, Ryouichi; Kato, Hiroaki

    2016-08-01

    Beyond the first peak of head-related transfer functions or pinna-related transfer functions (PRTFs) human pinnae are known to have two normal modes with "vertical" resonance patterns, involving two or three pressure anti-nodes in cavum, cymba, and fossa. However, little is known about individual variations in these modes, and there is no established model for estimating their center-frequencies from anthropometry. Here, with geometries of 38 pinnae measured, PRTFs were calculated and vertical modes visualized by numerical simulation. Most pinnae were found to have both Cavum-Fossa and Cavum-Cymba modes, with opposite-phase anti-nodes in cavum and either fossa or cymba, respectively. Nevertheless in both modes, fossa involvement varied substantially across pinnae, dependent on scaphoid fossa depth and cymba shallowness. Linear regression models were evaluated in mode frequency estimation, with 3322 measures derived from 31 pinna landmarks. The Cavum-Fossa normal mode frequency was best estimated [correlation coefficient r = 0.89, mean absolute error (MAE) = 257 Hz or 4.4%] by the distance from canal entrance to helix rim, and cymba horizontal depth. The Cavum-Cymba normal mode frequency was best estimated (r = 0.92, MAE = 247 Hz or 3.2%) by the sagittal-plane distance from concha floor to cymba anterior wall, and cavum horizontal depth. PMID:27586714

  13. Comparative Study of Various Normal Mode Analysis Techniques Based on Partial Hessians

    PubMed Central

    GHYSELS, AN; VAN SPEYBROECK, VERONIQUE; PAUWELS, EWALD; CATAK, SARON; BROOKS, BERNARD R.; VAN NECK, DIMITRI; WAROQUIER, MICHEL

    2014-01-01

    Standard normal mode analysis becomes problematic for complex molecular systems, as a result of both the high computational cost and the excessive amount of information when the full Hessian matrix is used. Several partial Hessian methods have been proposed in the literature, yielding approximate normal modes. These methods aim at reducing the computational load and/or calculating only the relevant normal modes of interest in a specific application. Each method has its own (dis)advantages and application field but guidelines for the most suitable choice are lacking. We have investigated several partial Hessian methods, including the Partial Hessian Vibrational Analysis (PHVA), the Mobile Block Hessian (MBH), and the Vibrational Subsystem Analysis (VSA). In this article, we focus on the benefits and drawbacks of these methods, in terms of the reproduction of localized modes, collective modes, and the performance in partially optimized structures. We find that the PHVA is suitable for describing localized modes, that the MBH not only reproduces localized and global modes but also serves as an analysis tool of the spectrum, and that the VSA is mostly useful for the reproduction of the low frequency spectrum. These guidelines are illustrated with the reproduction of the localized amine-stretch, the spectrum of quinine and a bis-cinchona derivative, and the low frequency modes of the LAO binding protein. PMID:19813181

  14. Rossby normal modes in nonuniform background configurations. I Simple fields. II - Equinox and solstice conditions

    NASA Technical Reports Server (NTRS)

    Salby, M. L.

    1981-01-01

    An investigation is conducted regarding the influence of mean field variations on the realization of planetary normal modes, taking into account the mode response and structure in the presence of simple background nonuniformities. It is found that mean field variations have the combined effect of depressing, shifting, and broadening the characteristic response of Rossby normal modes. While nonuniformities in both the mean wind and temperature fields contribute to the reduction in peak response, the former are primarily responsible for translation and spectral broadening. An investigation is conducted to determine which modes may be realized in actual atmospheric configurations and which may be identified. For both the equinox and solstice configurations, response peaks corresponding to all of the first four modes of wavenumbers 1, 2, and 3 are readily visible above the noise.

  15. Instantaneous normal mode analysis of the vibrational relaxation of the amide I mode of alanine dipeptide in water

    NASA Astrophysics Data System (ADS)

    Farag, Marwa H.; Zúñiga, José; Requena, Alberto; Bastida, Adolfo

    2013-05-01

    Nonequilibrium Molecular Dynamics (MD) simulations coupled to instantaneous normal modes (INMs) analysis are used to study the vibrational relaxation of the acetyl and amino-end amide I modes of the alanine dipeptide (AlaD) molecule dissolved in water (D2O). The INMs are assigned in terms of the equilibrium normal modes using the Effective Atomic Min-Cost algorithm as adapted to make use of the outputs of standard MD packages, a method which is well suited for the description of flexible molecules. The relaxation energy curves of both amide I modes show multiexponential decays, in good agreement with the experimental findings. It is found that ˜85%-90% of the energy relaxes through intramolecular vibrational redistribution. The main relaxation pathways are also identified. The rate at which energy is transferred into the solvent is similar for the acetyl-end and amino-end amide I modes. The conformational changes occurring during relaxation are investigated, showing that the populations of the alpha and beta region conformers are altered by energy transfer in such a way that it takes 15 ps for the equilibrium conformational populations to be recovered after the initial excitation of the AlaD molecule.

  16. Characterizing structure connectivity correlation with the default mode network in Alzheimer's patients and normal controls

    NASA Astrophysics Data System (ADS)

    Guo, Jia; Xu, Peng; Song, Chao; Yao, Li; Zhao, Xiaojie

    2012-03-01

    Magnetic resonance diffusion tensor imaging (DTI) is a kind of effective measure to do non-invasive investigation on brain fiber structure at present. Studies of fiber tracking based on DTI showed that there was structural connection of white matter fiber among the nodes of resting-state functional network, denoting that the connection of white matter was the basis of gray matter regions in functional network. Nevertheless, relationship between these structure connectivity regions and functional network has not been clearly indicated. Moreover, research of fMRI found that activation of default mode network (DMN) in Alzheimer's disease (AD) was significantly descended, especially in hippocampus and posterior cingulated cortex (PCC). The relationship between this change of DMN activity and structural connection among functional networks needs further research. In this study, fast marching tractography (FMT) algorithm was adopted to quantitative calculate fiber connectivity value between regions, and hippocampus and PCC which were two important regions in DMN related with AD were selected to compute white matter connection region between them in elderly normal control (NC) and AD patient. The fiber connectivity value was extracted to do the correlation analysis with activity intensity of DMN. Results showed that, between PCC and hippocampus of NC, there exited region with significant high connectivity value of white matter fiber whose performance has relatively strong correlation with the activity of DMN, while there was no significant white matter connection region between them for AD patient which might be related with reduced network activation in these two regions of AD.

  17. Extraction of acoustic normal mode depth functions using vertical line array data

    NASA Astrophysics Data System (ADS)

    Neilsen, Tracianne B.; Westwood, Evan K.

    2002-02-01

    A method for extracting the normal modes of acoustic propagation in the shallow ocean from sound recorded on a vertical line array (VLA) of hydrophones as a source travels nearby is presented. The mode extraction is accomplished by performing a singular value decomposition (SVD) of individual frequency components of the signal's temporally averaged, spatial cross-spectral density matrix. The SVD produces a matrix containing a mutually orthogonal set of basis functions, which are proportional to the depth-dependent normal modes, and a diagonal matrix containing the singular values, which are proportional to the modal source excitations and mode eigenvalues. The conditions under which the method is expected to work are found to be (1) sufficient depth sampling of the propagating modes by the VLA receivers; (2) sufficient source-VLA range sampling, and (3) sufficient range interval traversed by the source. The mode extraction method is applied to data from the Area Characterization Test II, conducted in September 1993 in the Hudson Canyon Area off the New Jersey coast. Modes are successfully extracted from cw tones recorded while (1) the source traveled along a range-independent track with constant bathymetry and (2) the source traveled up-slope with gradual changes in bathymetry. In addition, modes are successfully extracted at multiple frequencies from ambient noise.

  18. Dynamic and elastic properties of F-actin: a normal-modes analysis.

    PubMed Central

    ben-Avraham, D; Tirion, M M

    1995-01-01

    We examine the dynamic, elastic, and mechanical consequences of the proposed atomic models of F-actin, using a normal mode analysis. This initial analysis is done in vacuo and assumes that all monomers are rigid and equivalent. Our computation proceeds from the atomic level and, relying on a single fitting parameter, reproduces various experimental results, including persistence lengths, elastic moduli, and contact energies. The computations reveal modes of motion characteristic to all polymers, such as longitudinal pressure waves, torsional waves, and bending, as well as motions unique to F-actin. Motions typical to actin include a "groove-swinging" motion of the two long-pitch helices, as well as an axial slipping motion of the two strands. We prepare snapshots of thermally activated filaments and quantify the accumulation of azimuthal angular "disorder," variations in cross-over lengths, and various other fluctuations. We find that the orientation of a small number of select residues has a surprisingly large effect on the filament flexibility and elasticity characteristics. PMID:7787015

  19. Isotope effect in normal-to-local transition of acetylene bending modes

    DOE PAGES

    Ma, Jianyi; Xu, Dingguo; Guo, Hua; Tyng, Vivian; Kellman, Michael E.

    2012-01-01

    The normal-to-local transition for the bending modes of acetylene is considered a prelude to its isomerization to vinylidene. Here, such a transition in fully deuterated acetylene is investigated using a full-dimensional quantum model. It is found that the local benders emerge at much lower energies and bending quantum numbers than in the hydrogen isotopomer HCCH. This is accompanied by a transition to a second kind of bending mode called counter-rotator, again at lower energies and quantum numbers than in HCCH. These transitions are also investigated using bifurcation analysis of two empirical spectroscopic fitting Hamiltonians for pure bending modes, which helpsmore » to understand the origin of the transitions semiclassically as branchings or bifurcations out of the trans and normal bend modes when the latter become dynamically unstable. The results of the quantum model and the empirical bifurcation analysis are in very good agreement.« less

  20. Earth's normal mode spectrum below 1mHz observed with a superconducting gravimeter

    NASA Astrophysics Data System (ADS)

    Raja-Halli, A.; Virtanen, H.; Ruotsalainen, H.

    2012-04-01

    We present new observations of the normal modes 0S2, 0T2, 2S1 and 0S3 observed with the GWR T020 superconducting gravimeter at Metsähovi, Finland. Superconducting gravimeter is well suited for observing the normal mode spectrum of the Earth, primarily due to the low noise levels at seismic bands. Especially in the frequencies below 1mHz, superconducting gravimeters can provide valuable information on the behavior of the modes and further about the Earth's internal structure. The superconducting gravimeter GWR no.T020 has been operating continuously at Metsähovi, since August 1994. We have studied the gravimeter data after larger than magnitude M=8.0 earthquakes, which have occurred between August 1994 and December 2011. A total of 20 M>8.0 earthquakes occurred during this time. In this study we will show the observational threshold level of the GWR T020 gravimeter for the modes 0S2, 2S1, 0S3 and 0T2, and examine the behaviour of these modes. The properties of these gravest normal modes are of great interest as they are a direct result of the Earth's density profile and hence help to constrain the Earth models. The mode 0S2 can be observed in all studied spectra. However, the amplitude of the mode is only slightly above the noise level of 0.01nm/s2 after the weakest earthquakes studied. After earthquakes with magnitudes M>8.4 the splitting of the mode 0S2 into five separate peaks can be clearly seen in the 240 hour spectrum as well as the splitting of the mode 0S3. Modes 2S1 and 0T2 are detected just above the noise level after M>8.8 earthquakes. The toroidal mode 0T2 is observable with gravimeters only due to coupling effects created by rotating Earth and hence is observable only after the most powerful earthquakes studied. In addition we will present a comparison of the observed normal mode frequencies to the theoretical frequencies of the Earth's models PREM and 1066A. The comparison shows slight differences between the theoretical and observed frequency.

  1. Evaluation of Geometrically Nonlinear Reduced Order Models with Nonlinear Normal Modes

    DOE PAGES

    Kuether, Robert J.; Deaner, Brandon J.; Hollkamp, Joseph J.; Allen, Matthew S.

    2015-09-15

    Several reduced-order modeling strategies have been developed to create low-order models of geometrically nonlinear structures from detailed finite element models, allowing one to compute the dynamic response of the structure at a dramatically reduced cost. But, the parameters of these reduced-order models are estimated by applying a series of static loads to the finite element model, and the quality of the reduced-order model can be highly sensitive to the amplitudes of the static load cases used and to the type/number of modes used in the basis. Our paper proposes to combine reduced-order modeling and numerical continuation to estimate the nonlinearmore » normal modes of geometrically nonlinear finite element models. Not only does this make it possible to compute the nonlinear normal modes far more quickly than existing approaches, but the nonlinear normal modes are also shown to be an excellent metric by which the quality of the reduced-order model can be assessed. Hence, the second contribution of this work is to demonstrate how nonlinear normal modes can be used as a metric by which nonlinear reduced-order models can be compared. Moreover, various reduced-order models with hardening nonlinearities are compared for two different structures to demonstrate these concepts: a clamped–clamped beam model, and a more complicated finite element model of an exhaust panel cover.« less

  2. Evaluation of Geometrically Nonlinear Reduced Order Models with Nonlinear Normal Modes

    SciTech Connect

    Kuether, Robert J.; Deaner, Brandon J.; Hollkamp, Joseph J.; Allen, Matthew S.

    2015-09-15

    Several reduced-order modeling strategies have been developed to create low-order models of geometrically nonlinear structures from detailed finite element models, allowing one to compute the dynamic response of the structure at a dramatically reduced cost. But, the parameters of these reduced-order models are estimated by applying a series of static loads to the finite element model, and the quality of the reduced-order model can be highly sensitive to the amplitudes of the static load cases used and to the type/number of modes used in the basis. Our paper proposes to combine reduced-order modeling and numerical continuation to estimate the nonlinear normal modes of geometrically nonlinear finite element models. Not only does this make it possible to compute the nonlinear normal modes far more quickly than existing approaches, but the nonlinear normal modes are also shown to be an excellent metric by which the quality of the reduced-order model can be assessed. Hence, the second contribution of this work is to demonstrate how nonlinear normal modes can be used as a metric by which nonlinear reduced-order models can be compared. Moreover, various reduced-order models with hardening nonlinearities are compared for two different structures to demonstrate these concepts: a clamped–clamped beam model, and a more complicated finite element model of an exhaust panel cover.

  3. Normal mode determination of perovskite crystal structures with octahedral rotations: theory and applications.

    PubMed

    Islam, Mohammad A; Rondinelli, James M; Spanier, Jonathan E

    2013-05-01

    Nuclear site analysis methods are used to enumerate the normal modes of ABX3 perovskite polymorphs with octahedral rotations. We provide the modes of the 14 subgroups of the cubic aristotype describing the Glazer octahedral tilt patterns, which are obtained from rotations of the BX6 octahedra with different sense and amplitude about high-symmetry axes. We tabulate all normal modes of each tilt system and specify the contribution of each atomic species to the mode displacement pattern, elucidating the physical meaning of the symmetry unique modes. We have systematically generated 705 schematic atomic displacement patterns for the normal modes of all 15 (14 rotated + 1 unrotated) Glazer tilt systems. We show through some illustrative examples how to use these tables to identify the octahedral rotations, symmetric breathing, and first-order Jahn-Teller anti-symmetric breathing distortions of the BX6 octahedra, and the associated Raman selection rules. We anticipate that these tables and schematics will be useful in understanding the lattice dynamics of bulk perovskites and could serve as a reference point in elucidating the atomic origins of a wide range of physical properties of synthetic perovskite thin films and superlattices. PMID:23567868

  4. Majorana modes and transport across junctions of superconductors and normal metals

    NASA Astrophysics Data System (ADS)

    Sen, Diptiman; Thakurathi, Manisha; Deb, Oindrila

    2015-03-01

    We study Majorana modes and transport in one-dimensional systems with junctions of p-wave superconductors (SCs) and normal metal (NM) leads. For a system with a SC lying between two NM leads, it is known that there is a Majorana mode at the junction between the SC and each NM. If an impurity is present or the p-wave pairing amplitude changes sign at some point in the superconductor, two additional Majorana modes appear near that point. We study the effects of all these modes on the normal and Cooper pair conductances. The main effect is to shift the conductance peaks away from zero bias due to hybridization between the Majoranas; the shift oscillates and also decays exponentially as the length of the SC is increased. Using bosonization and the renormalization group (RG) method, we study the effect of interactions between the electrons on the Majorana modes and the conductances. We then consider a system with a junction of three SC regions connected to NM leads. The junction is parameterized by a scattering matrix. Depending on the relative signs of the pairing amplitudes in the three SCs, there may be one or three Majorana modes at the junction. We study the effect of interactions on these modes using an RG analysis which is valid for weak interactions. We thank DST, India and CSIR, India for financial support.

  5. A phylogenetic analysis of normal modes evolution in enzymes and its relationship to enzyme function.

    PubMed

    Lai, Jason; Jin, Jing; Kubelka, Jan; Liberles, David A

    2012-09-21

    Since the dynamic nature of protein structures is essential for enzymatic function, it is expected that functional evolution can be inferred from the changes in protein dynamics. However, dynamics can also diverge neutrally with sequence substitution between enzymes without changes of function. In this study, a phylogenetic approach is implemented to explore the relationship between enzyme dynamics and function through evolutionary history. Protein dynamics are described by normal mode analysis based on a simplified harmonic potential force field applied to the reduced C(α) representation of the protein structure while enzymatic function is described by Enzyme Commission numbers. Similarity of the binding pocket dynamics at each branch of the protein family's phylogeny was analyzed in two ways: (1) explicitly by quantifying the normal mode overlap calculated for the reconstructed ancestral proteins at each end and (2) implicitly using a diffusion model to obtain the reconstructed lineage-specific changes in the normal modes. Both explicit and implicit ancestral reconstruction identified generally faster rates of change in dynamics compared with the expected change from neutral evolution at the branches of potential functional divergences for the α-amylase, D-isomer-specific 2-hydroxyacid dehydrogenase, and copper-containing amine oxidase protein families. Normal mode analysis added additional information over just comparing the RMSD of static structures. However, the branch-specific changes were not statistically significant compared to background function-independent neutral rates of change of dynamic properties and blind application of the analysis would not enable prediction of changes in enzyme specificity.

  6. Time-frequency characterization of nonlinear normal modes and challenges in nonlinearity identification of dynamical systems

    NASA Astrophysics Data System (ADS)

    Pai, P. Frank

    2011-10-01

    Presented here is a new time-frequency signal processing methodology based on Hilbert-Huang transform (HHT) and a new conjugate-pair decomposition (CPD) method for characterization of nonlinear normal modes and parametric identification of nonlinear multiple-degree-of-freedom dynamical systems. Different from short-time Fourier transform and wavelet transform, HHT uses the apparent time scales revealed by the signal's local maxima and minima to sequentially sift components of different time scales. Because HHT does not use pre-determined basis functions and function orthogonality for component extraction, it provides more accurate time-varying amplitudes and frequencies of extracted components for accurate estimation of system characteristics and nonlinearities. CPD uses adaptive local harmonics and function orthogonality to extract and track time-localized nonlinearity-distorted harmonics without the end effect that destroys the accuracy of HHT at the two data ends. For parametric identification, the method only needs to process one steady-state response (a free undamped modal vibration or a steady-state response to a harmonic excitation) and uses amplitude-dependent dynamic characteristics derived from perturbation analysis to determine the type and order of nonlinearity and system parameters. A nonlinear two-degree-of-freedom system is used to illustrate the concepts and characterization of nonlinear normal modes, vibration localization, and nonlinear modal coupling. Numerical simulations show that the proposed method can provide accurate time-frequency characterization of nonlinear normal modes and parametric identification of nonlinear dynamical systems. Moreover, results show that nonlinear modal coupling makes it impossible to decompose a general nonlinear response of a highly nonlinear system into nonlinear normal modes even if nonlinear normal modes exist in the system.

  7. The effect of truncating the normal mode coupling equations on synthetic spectra

    NASA Astrophysics Data System (ADS)

    Akbarashrafi, F.; Valentine, A. P.; Al-Attar, D.; Trampert, J.

    2015-12-01

    The free oscillations, or normal modes, of the Earth provide important constraints on the long-wavelength structure of our planet. Calculations using normal modes are also necessary if the effects of gravity are to be fully modeled in seismic waveforms, which becomes important at low frequencies. To implement these calculations, we typically initially compute the normal modes (eigenfunctions) of a spherically-symmetric model such as PREM. These form a complete set of basis functions, which may then be used to describe the seismic response of laterally heterogeneous models. This procedure is known as 'mode coupling'. In order to implement the calculation, it is necessary to select a finite subset of modes (invariably defined by a frequency range) to be considered. This truncation of the infinite-dimensional equations necessarily introduces an error into the results. Here, we consider the fundamental question: if we wish to calculate synthetic spectra in a given frequency range, how many modes must we couple for the resulting spectra to be sufficiently accurate? To investigate this question, we compute spectra in the 3D model S20RTS up to 2mHz, but allowing coupling with all modes up to 5mHz. We then explore how the spectra change as we reduce the upper frequency used in the coupling. We compare this to the effects introduced by altering the 3D density structure of the model. Clearly, if we wish to image Earth's density structure accurately, it is important that the truncation error is small compared to this signal.

  8. A coupling model for quasi-normal modes of photonic resonators

    NASA Astrophysics Data System (ADS)

    Vial, Benjamin; Hao, Yang

    2016-11-01

    We develop a model for the coupling of quasi-normal modes in open photonic systems consisting of two resonators. By expressing the modes of the coupled system as a linear combination of the modes of the individual particles, we obtain a generalized eigenvalue problem involving small size dense matrices. We apply this technique to dielectric rod dimmer of rectangular cross section for transverse electric polarization in a two-dimensional setup. The results of our model show excellent agreement with full wave finite element simulations. We provide a convergence analysis, and a simplified model with a few modes to study the influence of the relative position of the two resonators. This model provides interesting physical insights on the coupling scheme at stake in such systems and pave the way for systematic and efficient design and optimization of resonances in more complicated systems, for applications including sensing, antennae and spectral filtering.

  9. M-mode echocardiography in normal children and adolescents: some new perspectives.

    PubMed

    Lester, L A; Sodt, P C; Hutcheon, N; Arcilla, R A

    1987-01-01

    Normal M-mode echocardiography values were determined using computer-assisted measurements of echocardiograms (ECHO) in 202 children and young adults 25 days to 23 years of age: 77 were female, and 125 were male and, reflecting the population served by our Center, 99 were black and 103 were white children. The values for left and right heart wall thicknesses and chamber sizes were graphically displayed as a function of body surface area, and with an illustration of the regression line and 2 standard deviation (SD) range of normal for each parameter. In addition, normal ECHO predicting equations for dimension and function parameters were derived using multiple linear regression analysis with age, height, weight, sex, race, and heart rate as independent variables. A comparison was made between the observed data and the data derived from the normal predicting equations for each of the parameters. Also, values obtained from these equations were compared to data generated from other published normal predicting equations. A description of the digitizer measurements, computer interfacing, and a sample ECHO report form utilizing the predicted normal ranges for each of the parameters is presented. We propose that quantitative M-mode echocardiographic reporting should be easily accessible to all pediatric cardiology laboratories.

  10. Linear perturbations of black holes: stability, quasi-normal modes and tails

    NASA Astrophysics Data System (ADS)

    Zhidenko, Alexander

    2009-03-01

    Black holes have their proper oscillations, which are called the quasi-normal modes. The proper oscillations of astrophysical black holes can be observed in the nearest future with the help of gravitational wave detectors. Quasi-normal modes are also very important in the context of testing of the stability of black objects, the anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence and in higher dimensional theories, such as the brane-world scenarios and string theory. This dissertation reviews a number of works, which provide a thorough study of the quasi-normal spectrum of a wide class of black holes in four and higher dimensions for fields of various spin and gravitational perturbations. We have studied numerically the dependance of the quasi-normal modes on a number of factors, such as the presence of the cosmological constant, the Gauss-Bonnet parameter or the aether in the space-time, the dependance of the spectrum on parameters of the black hole and fields under consideration. By the analysis of the quasi-normal spectrum, we have studied the stability of higher dimensional Reissner-Nordstrom-de Sitter black holes, Kaluza-Klein black holes with squashed horizons, Gauss-Bonnet black holes and black strings. Special attention is paid to the evolution of massive fields in the background of various black holes. We have considered their quasi-normal ringing and the late-time tails. In addition, we present two new numerical techniques: a generalisation of the Nollert improvement of the Frobenius method for higher dimensional problems and a qualitatively new method, which allows to calculate quasi-normal frequencies for black holes, which metrics are not known analytically.

  11. Free and forced Rossby normal modes in a rectangular gulf of arbitrary orientation

    NASA Astrophysics Data System (ADS)

    Graef, Federico

    2016-09-01

    A free Rossby normal mode in a rectangular gulf of arbitrary orientation is constructed by considering the reflection of a Rossby mode in a channel at the head of the gulf. Therefore, it is the superposition of four Rossby waves in an otherwise unbounded ocean with the same frequency and wavenumbers perpendicular to the gulf axis whose difference is equal to 2mπ/W, where m is a positive integer and W the gulf's width. The lower (or higher) modes with small m (or large m) are oscillatory (evanescent) in the coordinate along the gulf; these are elucidated geometrically. However for oceanographically realistic parameter values, most of the modes are evanescent. When the gulf is forced at the mouth with a single Fourier component, the response is in general an infinite sum of modes that are needed to match the value of the streamfunction at the gulf's entrance. The dominant mode of the response is the resonant one, which corresponds to forcing with a frequency ω and wavenumber normal to the gulf axis η appropriate to a gulf mode: η =- β sin α/(2ω) ± Mπ/W, where α is the angle between the gulf's axis and the eastern direction (+ve clockwise) and M the resonant's mode number. For zonal gulfs ω drops out of the resonance condition. For the special cases η = 0 in which the free surface goes up and down at the mouth with no flow through it, or a flow with a sinusoidal profile, resonant modes can get excited for very specific frequencies (only for non-zonal gulfs in the η = 0 case). The resonant mode is around the annual frequency for a wide range of gulf orientations α ∈ [40°, 130°] or α ∈ [220°, 310°] and gulf widths between 150 and 200 km; these include the Gulf of California and the Adriatic Sea. If η is imaginary, i.e. a flow with an exponential profile, there is no resonance. In general less modes get excited if the gulf is zonally oriented.

  12. Comparison of intrinsic dynamics of cytochrome p450 proteins using normal mode analysis

    PubMed Central

    Dorner, Mariah E; McMunn, Ryan D; Bartholow, Thomas G; Calhoon, Brecken E; Conlon, Michelle R; Dulli, Jessica M; Fehling, Samuel C; Fisher, Cody R; Hodgson, Shane W; Keenan, Shawn W; Kruger, Alyssa N; Mabin, Justin W; Mazula, Daniel L; Monte, Christopher A; Olthafer, Augustus; Sexton, Ashley E; Soderholm, Beatrice R; Strom, Alexander M; Hati, Sanchita

    2015-01-01

    Cytochrome P450 enzymes are hemeproteins that catalyze the monooxygenation of a wide-range of structurally diverse substrates of endogenous and exogenous origin. These heme monooxygenases receive electrons from NADH/NADPH via electron transfer proteins. The cytochrome P450 enzymes, which constitute a diverse superfamily of more than 8,700 proteins, share a common tertiary fold but < 25% sequence identity. Based on their electron transfer protein partner, cytochrome P450 proteins are classified into six broad classes. Traditional methods of pro are based on the canonical paradigm that attributes proteins' function to their three-dimensional structure, which is determined by their primary structure that is the amino acid sequence. It is increasingly recognized that protein dynamics play an important role in molecular recognition and catalytic activity. As the mobility of a protein is an intrinsic property that is encrypted in its primary structure, we examined if different classes of cytochrome P450 enzymes display any unique patterns of intrinsic mobility. Normal mode analysis was performed to characterize the intrinsic dynamics of five classes of cytochrome P450 proteins. The present study revealed that cytochrome P450 enzymes share a strong dynamic similarity (root mean squared inner product > 55% and Bhattacharyya coefficient > 80%), despite the low sequence identity (< 25%) and sequence similarity (< 50%) across the cytochrome P450 superfamily. Noticeable differences in Cα atom fluctuations of structural elements responsible for substrate binding were noticed. These differences in residue fluctuations might be crucial for substrate selectivity in these enzymes. PMID:26130403

  13. Effects of normal mode loss in dielectric waveguide directional couplers and interferometers

    NASA Astrophysics Data System (ADS)

    Youngquist, R. C.; Stokes, L. F.; Shaw, H. J.

    1983-12-01

    Theoretical arguments and experimental evidence are presented to show that the two fundamental normal modes of a coupled waveguide structure have different attenuations in traversing such a structure. The effects of this phenomenon on evanescent wave directional counters and interferometers are derived. Parasitic effects in Mach-Zehnder and Sagnac interferometers utilizing directional couplers are described. An asymmetric output for the recently demonstrated all-single-mode fiber resonator is predicted and compared to experimental results. Some qualitative results are presented for integrated optic directional coupler switches.

  14. Allosteric transitions in biological nanomachines are described by robust normal modes of elastic networks.

    PubMed

    Zheng, Wenjun; Brooks, Bernard R; Thirumalai, D

    2009-04-01

    Allostery forms the basis of intra-molecular communications in various enzymes, however the underlying conformational changes are largely elusive. Recently, we have proposed to employ an elastic model based normal mode analysis to investigate the allosteric transitions in several molecular nanomachines (including myosin II, DNA polymerase and chaperonin GroEL). After combining with bioinformatics analysis of the evolutionary sequence variations, we have been able to identify the highly conserved and robust modes of collective motions that are capable of transmitting molecular signals over long distances.

  15. Fifth-order raman spectrum of an atomic liquid: simulation and instantaneous-normal-mode calculation

    PubMed

    Ma; Stratt

    2000-07-31

    Experimental artifacts and technical difficulties in carrying out theoretical calculations have consistently frustrated attempts to obtain the two-dimensional (5th-order) Raman spectrum of a liquid. We report here a new theoretical development: the first microscopic numerical simulation of the 5th-order Raman signal in a liquid. Comparison with an instantaneous-normal-mode treatment, a fully microscopic model which interprets liquid dynamics as arising from coherent harmonic modes, shows that the 5th-order spectrum reveals profound effects stemming from dynamical anharmonicity.

  16. Majorana modes and transport across junctions of superconductors and normal metals.

    PubMed

    Thakurathi, Manisha; Deb, Oindrila; Sen, Diptiman

    2015-07-15

    We study Majorana modes and transport in one-dimensional systems with a p-wave superconductor (SC) and normal metal leads. For a system with an SC lying between two leads, it is known that there is a Majorana mode at the junction between the SC and each lead. If the p-wave pairing Δ changes sign or if a strong impurity is present at some point inside the SC, two additional Majorana modes appear near that point. We study the effect of all these modes on the sub-gap conductance between the leads and the SC. We derive an analytical expression as a function of Δ and the length L of the SC for the energy shifts of the Majorana modes at the junctions due to hybridization between them; the shifts oscillate and decay exponentially as L is increased. The energy shifts exactly match the location of the peaks in the conductance. Using bosonization and the renormalization group method, we study the effect of interactions between the electrons on Δ and the strengths of an impurity inside the SC or the barriers between the SC and the leads; this in turn affects the Majorana modes and the conductance. Finally, we propose a novel experimental realization of these systems, in particular of a system where Δ changes sign at one point inside the SC. PMID:26086479

  17. Wave normal direction and spectral properties of whistler mode hiss observed on the DE 1 satellite

    NASA Technical Reports Server (NTRS)

    Sonwalkar, Vikas S.; Inan, Umran S.

    1988-01-01

    Hiss is represented by a field distribution function in order to investigate magnetospheric hiss as a spatially and temporally enduring phenomenon. The study takes into account the whistler mode relationships and the linear and spin motion of the satellite. Hiss signals received on September 23, 1983 by the DE-1 electric and magnetic field antennas are analyzed. A wave normal angle of 60 + or - 5 deg with respect to the local geomagnetic field is found near the geomagnetic equator, and wave normal directions from 30-80 deg with respect to the local geomagnetic field are found away from the equator.

  18. High-frequency Born synthetic seismograms based on coupled normal modes

    USGS Publications Warehouse

    Pollitz, F.

    2011-01-01

    High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered wavefields and the pure-path approximation to modulate the phase of incident and scattered wavefields. This depends upon a decomposition of the aspherical structure into smooth and rough components. The uncoupled integral equations are discretized and solved in the frequency domain, and time domain results are obtained by inverse Fourier transform. Examples show the utility of the normal mode approach to synthesize the seismic wavefields resulting from interaction with a combination of rough and smooth structural heterogeneities. This approach is applied to an ~4 Hz shallow crustal wave propagation around the site of the San Andreas Fault Observatory at Depth (SAFOD). ?? The Author Geophysical Journal International ?? 2011 RAS.

  19. High-frequency Born synthetic seismograms based on coupled normal modes

    USGS Publications Warehouse

    Pollitz, Fred F.

    2011-01-01

    High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered wavefields and the pure-path approximation to modulate the phase of incident and scattered wavefields. This depends upon a decomposition of the aspherical structure into smooth and rough components. The uncoupled integral equations are discretized and solved in the frequency domain, and time domain results are obtained by inverse Fourier transform. Examples show the utility of the normal mode approach to synthesize the seismic wavefields resulting from interaction with a combination of rough and smooth structural heterogeneities. This approach is applied to an ∼4 Hz shallow crustal wave propagation around the site of the San Andreas Fault Observatory at Depth (SAFOD).

  20. Actively mode-locked Raman fiber laser.

    PubMed

    Yang, Xuezong; Zhang, Lei; Jiang, Huawei; Fan, Tingwei; Feng, Yan

    2015-07-27

    Active mode-locking of Raman fiber laser is experimentally investigated for the first time. An all fiber connected and polarization maintaining loop cavity of ~500 m long is pumped by a linearly polarized 1120 nm Yb fiber laser and modulated by an acousto-optic modulator. Stable 2 ns width pulse train at 1178 nm is obtained with modulator opening time of > 50 ns. At higher power, pulses become longer, and second order Raman Stokes could take place, which however can be suppressed by adjusting the open time and modulation frequency. Transient pulse evolution measurement confirms the absence of relaxation oscillation in Raman fiber laser. Tuning of repetition rate from 392 kHz to 31.37 MHz is obtained with harmonic mode locking. PMID:26367642

  1. Comments on compressible effects on Alfven normal modes in nonuniform plasmas

    NASA Technical Reports Server (NTRS)

    Mok, Y.; Einaudi, G.

    1990-01-01

    The paper discusses the regime of validity of the theory of dissipative Alfven normal modes presented by Mok and Einaudi (1985) and Einaudi and Mok (1985), which was based on the incompressible closure of the system of ideal MHD equations. Some simple extensions of the earlier results to the compressible case are described. In addition, certain misunderstandings of this work, which have appeared in other papers, are clarified.

  2. A phylogenetic analysis of normal modes evolution in enzymes and its relationship to enzyme function

    PubMed Central

    Lai, Jason; Jin, Jing; Kubelka, Jan; Liberles, David A.

    2012-01-01

    Since the dynamic nature of protein structures is essential for enzymatic function, it is expected that the functional evolution can be inferred from the changes in the protein dynamics. However, dynamics can also diverge neutrally with sequence substitution between enzymes without changes of function. In this study, a phylogenetic approach is implemented to explore the relationship between enzyme dynamics and function through evolutionary history. Protein dynamics are described by normal mode analysis based on a simplified harmonic potential force field applied to the reduced Cα representation of the protein structure while enzymatic function is described by Enzyme Commission (EC) numbers. Similarity of the binding pocket dynamics at each branch of the protein family’s phylogeny was analyzed in two ways: 1) explicitly by quantifying the normal mode overlap calculated for the reconstructed ancestral proteins at each end and 2) implicitly using a diffusion model to obtain the reconstructed lineage-specific changes in the normal modes. Both explicit and implicit ancestral reconstruction identified generally faster rates of change in dynamics compared with the expected change from neutral evolution at the branches of potential functional divergences for the alpha-amylase, D-isomer specific 2-hydroxyacid dehydrogenase, and copper-containing amine oxidase protein families. Normal modes analysis added additional information over just comparing the RMSD of static structures. However, the branch-specific changes were not statistically significant compared to background function-independent neutral rates of change of dynamic properties and blind application of the analysis would not enable prediction of changes in enzyme specificity. PMID:22651983

  3. A brief study of quasi-normal modes in relativistic stars using algebraic computation

    SciTech Connect

    Campos, M. de

    2010-11-12

    The damped oscillations in relativistic stars generate gravitational waves that in the literature appear under the general denomination of quasi-normal modes. In this brief note we want offer some information about the use of algebraic computation to obtain the field equations and the perturbed version of them, in the context of general relativity theory, that is the framework to study gravitational waves in this work.

  4. Charge transfer mobility of naphthodithiophenediimide derivative: Normal-mode and bond length relaxation analysis

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyan; Liu, Yujuan; Zheng, Yujun

    2016-02-01

    In this letter, the charge transfer mobility of naphthalenediimide (NDTI) derivative is investigated. By employing the normal-mode analysis and bond length relaxation analysis, the influences of chemical elements on reorganization energies and intermolecular electronic couplings are investigated in NDTI derivative. The results show that the introduction of atom O would decrease reorganization energy in hole-hopping process and increase electronic coupling. This analysis encourages the molecular and material design in organic semiconductors.

  5. Simulation of Two-Dimensional Infrared Spectroscopy of Peptides Using Localized Normal Modes.

    PubMed

    Hanson-Heine, Magnus W D; Husseini, Fouad S; Hirst, Jonathan D; Besley, Nicholas A

    2016-04-12

    Nonlinear two-dimensional infrared spectroscopy (2DIR) is most commonly simulated within the framework of the exciton method. The key parameters for these calculations include the frequency of the oscillators within their molecular environments and coupling constants that describe the strength of coupling between the oscillators. It is shown that these quantities can be obtained directly from harmonic frequency calculations by exploiting a procedure that localizes the normal modes. This approach is demonstrated using the amide I modes of polypeptides. For linear and cyclic diamides and hexapeptide Z-Aib-L-Leu-(Aib)2-Gly-Aib-OtBu, the computed parameters are compared with those from existing schemes, and the resulting 2DIR spectra are consistent with experimental observations. The incorporation of conformational averaging of structures from molecular dynamics simulations is discussed, and a hybrid scheme wherein the Hamiltonian matrix from the quantum chemical local-mode approach is combined with fluctuations from empirical schemes is shown to be consistent with experiment. The work demonstrates that localized vibrational modes can provide a foundation for the calculation of 2DIR spectra that does not rely on extensive parametrization and can be applied to a wide range of systems. For systems that are too large for quantum chemical harmonic frequency calculations, the local-mode approach provides a convenient platform for the development of site frequency and coupling maps. PMID:26913672

  6. Normal force of magnetorheological fluids with foam metal under oscillatory shear modes

    NASA Astrophysics Data System (ADS)

    Yao, Xingan; Liu, Chuanwen; Liang, Huang; Qin, Huafeng; Yu, Qibing; Li, Chuan

    2016-04-01

    The normal force of magnetorheological (MR) fluids in porous foam metal was investigated in this paper. The dynamic repulsive normal force was studied using an advanced commercial rheometer under oscillatory shear modes. In the presence of magnetic fields, the influences of time, strain amplitude, frequency and shear rate on the normal force of MR fluids drawn from the porous foam metal were systematically analysed. The experimental results indicated that the magnetic field had the greatest effect on the normal force, and the effect increased incrementally with the magnetic field. Increasing the magnetic field produced a step-wise increase in the shear gap. However, other factors in the presence of a constant magnetic field only had weak effects on the normal force. This behaviour can be regarded as a magnetic field-enhanced normal force, as increases in the magnetic field resulted in more MR fluids being released from the porous foam metal, and the chain-like magnetic particles in the MR fluids becoming more elongated with aggregates spanning the gap between the shear plates.

  7. Dissipative soliton in actively mode-locked fiber laser.

    PubMed

    Wang, Ruixin; Dai, Yitang; Yan, Li; Wu, Jian; Xu, Kun; Li, Yan; Lin, Jintong

    2012-03-12

    A dissipative soliton in an all-normal-dispersion actively mode-locked ytterbium-doped fiber laser is reported for the first time. Pulses with 10-ps duration and edge-to-edge bandwidth of 9 nm are generated, and then extra-cavity compressed down to 560 fs due to the large chirp. Widely wavelength tuning between 1031 and 1080 nm is achieved by adjusting the driving frequency only. Our simulation shows that the proposed laser operates in the dissipative soliton shaping regime.

  8. Unstable modes in supercooled and normal liquids: Density of states, energy barriers, and self-diffusion

    NASA Astrophysics Data System (ADS)

    Keyes, T.

    1994-09-01

    The unstable mode density of states <ρu(ω;T)> is obtained from computer simulation and is analyzed, theoretically and empirically, over a broad range of supercooled and normal liquid temperatures in the unit density Lennard-Jones liquid. The functional form of <ρu(ω;T)> is determined and the ω, T dependence is seen to be consistent with a theory given by us previously. The parameters in the theory are determined and are related to the topological features of the potential energy surface in the configuration space; it appears that diffusion involves a low degree of cooperativity at all but the lowest temperatures. It is shown that analysis of <ρu(ω;T)> yields considerable information about the energy barriers to diffusion, namely, a characteristic ω-dependent energy and the distribution of barrier heights, gν(E). The improved description of <ρu(ω;T)> obtained in the paper is used to implement normal mode theory of the self-diffusion constant D(T) with no undetermined constants; agreement with simulation in the supercooled liquid is excellent. Use of a lower frequency cutoff on the contribution of unstable modes to diffusion, in an attempt to remove spurious contributions from anharmonicities unrelated to barrier crossing, yields the Zwanzig-Bassler temperature dependence for D(T). It is argued that the distribution of barriers plays a crucial role in determining the T dependence of the self-diffusion constant.

  9. Accretion onto magnetized neutron stars - Normal mode analysis of the interchange instability at the magnetopause

    NASA Technical Reports Server (NTRS)

    Arons, J.; Lea, S. M.

    1976-01-01

    Results are reported for a linearized hydromagnetic stability analysis of the magnetopause of an accreting neutron star. The magnetosphere is assumed to be slowly rotating, and the plasma just outside the magnetopause is assumed to be weakly magnetized. The plasma layer is assumed to be bounded above by a shock wave and to be thin compared with the radius of the magnetosphere. Under these circumstances, the growing modes are shown to be localized in the direction parallel to the zero-order magnetic field, but the structure of the modes is still similar to the flute mode. An expression for the growth rate at each magnetic latitude is obtained in terms of the magnitude of the gravitational acceleration normal to the surface, the azimuthal mode number, the radius of the magnetosphere, the height of the shock above the magnetopause, and the effective Atwood number which embodies the stabilizing effects of favorable curvature and magnetic tension. The effective Atwood number is calculated, and the stabilizing effects of viscosity and aligned flow parallel to the magnetopause are discussed.

  10. Cavity quantum optomechanics of ultracold atoms in an optical lattice: Normal-mode splitting

    SciTech Connect

    Bhattacherjee, Aranya B.

    2009-10-15

    We consider the dynamics of a movable mirror (cantilever) of a cavity coupled through radiation pressure to the light scattered from ultracold atoms in an optical lattice. Scattering from different atomic quantum states creates different quantum states of the scattered light, which can be distinguished by measurements of the displacement spectrum of the cantilever. We show that for large pump intensities the steady-state displacement of the cantilever shows bistable behavior. Due to atomic back action, the displacement spectrum of the cantilever is modified and depends on the position of the condensate in the Brillouin zone. We further analyze the occurrence of splitting of the normal mode into three modes due to mixing of the mechanical motion with the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction.

  11. Dynamical analysis of tRNA Gln-GlnRS complex using normal mode calculation

    NASA Astrophysics Data System (ADS)

    Nakamura, Shugo; Ikeguchi, Mitsunori; Shimizu, Kentaro

    2003-04-01

    We applied normal mode calculation in internal coordinates to a complex of glutamine transfer RNA (tRNA Gln) and glutaminyl-tRNA synthetase (GlnRS). Calculated deviations of atoms agreed well with those obtained from X-ray data. The differences of motions corresponding to low mode frequencies between the free state and the complex state were analyzed. For GlnRS, many motions in the free state were conserved in the complex state, while the dynamics of tRNA Gln was largely affected by the complex formation. Superimposed images of the conserved and non-conserved motions of tRNA Gln clearly indicated the restricted direction of motions in the complex.

  12. On Quasi-Normal Modes, Area Quantization and Bohr Correspondence Principle

    NASA Astrophysics Data System (ADS)

    Corda, Christian

    2015-10-01

    In (Int. Journ. Mod. Phys. D 14, 181 2005), the author Khriplovich verbatim claims that "the correspondence principle does not dictate any relation between the asymptotics of quasinormal modes and the spectrum of quantized black holes" and that "this belief is in conflict with simple physical arguments". In this paper we analyze Khriplovich's criticisms and realize that they work only for the original proposal by Hod, while they do not work for the improvements suggested by Maggiore and recently finalized by the author and collaborators through a connection between Hawking radiation and black hole (BH) quasi-normal modes (QNMs). This is a model of quantum BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. Thus, QNMs can be really interpreted as BH quantum levels (the "electrons" of the "Bohr-like BH model").Our results have also important implications on the BH information puzzle.

  13. An instrument for direct observations of seismic and normal-mode rotational oscillations of the Earth.

    PubMed

    Cowsik, R

    2007-04-24

    The rotations around the vertical axis associated with the normal mode oscillations of the Earth and those induced by the seismic and other disturbances have been very difficult to observe directly. Such observations will provide additional information for 3D modeling of the Earth and for understanding earthquakes and other underground explosions. In this paper, we describe the design of an instrument capable of measuring the rotational motions associated with the seismic oscillations of the Earth, including the lowest frequency normal mode at nu approximately 3.7 x 10(-4) Hz. The instrument consists of a torsion balance with a natural frequency of nu(0) approximately 1.6 x 10(-4) Hz, which is observed by an autocollimating optical lever of high angular resolution and dynamic range. Thermal noise limits the sensitivity of the apparatus to amplitudes of approximately 1.5 x 10(-9) rad at the lowest frequency normal mode and the sensitivity improves as nu(-3/2) with increasing frequency. Further improvements in sensitivity by about two orders of magnitude may be achieved by operating the balance at cryogenic temperatures. Alternatively, the instrument can be made more robust with a reduced sensitivity by increasing nu(0) to approximately 10(-2) Hz. This instrument thus complements the ongoing effort by Igel and others to study rotational motions using ring laser gyroscopes and constitutes a positive response to the clarion call for developments in rotation seismology by Igel, Lee, and Todorovska [H. Igel, W.H.K. Lee and M.I. Todorovska, AGU Fall Meeting 2006, Rotational Seismology Sessions: S22A,S23B, Inauguration of the International Working Group on Rotational Seismology (IWGoRS)].

  14. An instrument for direct observations of seismic and normal-mode rotational oscillations of the Earth

    PubMed Central

    Cowsik, R.

    2007-01-01

    The rotations around the vertical axis associated with the normal mode oscillations of the Earth and those induced by the seismic and other disturbances have been very difficult to observe directly. Such observations will provide additional information for 3D modeling of the Earth and for understanding earthquakes and other underground explosions. In this paper, we describe the design of an instrument capable of measuring the rotational motions associated with the seismic oscillations of the Earth, including the lowest frequency normal mode at ν ≈ 3.7 × 10−4 Hz. The instrument consists of a torsion balance with a natural frequency of ν0 ≈ 1.6 × 10−4 Hz, which is observed by an autocollimating optical lever of high angular resolution and dynamic range. Thermal noise limits the sensitivity of the apparatus to amplitudes of ≈ 1.5 × 10−9 rad at the lowest frequency normal mode and the sensitivity improves as ν−3/2 with increasing frequency. Further improvements in sensitivity by about two orders of magnitude may be achieved by operating the balance at cryogenic temperatures. Alternatively, the instrument can be made more robust with a reduced sensitivity by increasing ν0 to ≈10−2 Hz. This instrument thus complements the ongoing effort by Igel and others to study rotational motions using ring laser gyroscopes and constitutes a positive response to the clarion call for developments in rotation seismology by Igel, Lee, and Todorovska [H. Igel, W.H.K. Lee and M.I. Todorovska, AGU Fall Meeting 2006, Rotational Seismology Sessions: S22A,S23B, Inauguration of the International Working Group on Rotational Seismology (IWGoRS)]. PMID:17438268

  15. Supercontinuum generation by noise-like pulses transmitted through normally dispersive standard single-mode fibers.

    PubMed

    Zaytsev, Alexey; Lin, Chih-Hsuan; You, Yi-Jing; Chung, Chia-Chun; Wang, Chi-Luen; Pan, Ci-Ling

    2013-07-01

    We report generation of broadband supercontinuum (SC) by noise-like pulses (NLPs) with a central wavelength of 1070 nm propagating through a long piece of standard single-mode fibers (~100 meters) in normal dispersion region far from the zero-dispersion point. Theoretical simulations indicate that the physical mechanism of SC generation is due to nonlinear effects in fibers. The cascaded Raman scattering is responsible for significant spectral broadening in the longer wavelength regions whereas the Kerr effect results in smoothing of SC generated spectrum. The SC exhibits low threshold (43 nJ) and a flat spectrum over 1050-1250 nm. PMID:23842392

  16. All-normal dispersion, all-fibered PM laser mode-locked by SESAM.

    PubMed

    Lecourt, Jean-Bernard; Duterte, Charles; Narbonneau, François; Kinet, Damien; Hernandez, Yves; Giannone, Domenico

    2012-05-21

    We report a PM all-normal, all-in-fiber passively mode-locked laser operating at 1030 nm. The main pulse shaping mechanism is provided by a tilted chirped-FBG. The laser delivers nanojoule range highly chirped pulses at a repetition rate of about 40 MHz. The FWHM of the optical spectrum is up to 7.8 nm leading to sub-500 fs compressed optical pulses. The influence of the filtering bandwidth and the output coupling ratio has been investigated. PMID:22714177

  17. Identification of nonlinear normal modes of engineering structures under broadband forcing

    NASA Astrophysics Data System (ADS)

    Noël, Jean-Philippe; Renson, L.; Grappasonni, C.; Kerschen, G.

    2016-06-01

    The objective of the present paper is to develop a two-step methodology integrating system identification and numerical continuation for the experimental extraction of nonlinear normal modes (NNMs) under broadband forcing. The first step processes acquired input and output data to derive an experimental state-space model of the structure. The second step converts this state-space model into a model in modal space from which NNMs are computed using shooting and pseudo-arclength continuation. The method is demonstrated using noisy synthetic data simulated on a cantilever beam with a hardening-softening nonlinearity at its free end.

  18. Analytical treatment of the interaction between light, plasmonic and quantum resonances: quasi-normal mode expansion

    NASA Astrophysics Data System (ADS)

    Perrin, M.; Yang, J.; Lalanne, P.

    2016-02-01

    We summarize here, and detail with numerical examples, the Quasi-Normal Mode theory which has been developed in a recent series of papers dealing with classical and quantum plasmonics. We present the semi-analytical formalism capable of handling the coupling of electromagnetic sources, such as point dipoles or free-propagating fields, with various kinds of dissipative and dispersive resonators. Due to its analyticity, the approach is very intuitive, and very versatile and can be applied to canonical problems of quantum optics and sensing with nanoresonators.

  19. Normalization.

    ERIC Educational Resources Information Center

    Cuevas, Eduardo J.

    1997-01-01

    Discusses cornerstone of Montessori theory, normalization, which asserts that if a child is placed in an optimum prepared environment where inner impulses match external opportunities, the undeviated self emerges, a being totally in harmony with its surroundings. Makes distinctions regarding normalization, normalized, and normality, indicating how…

  20. Experimental and numerical studies of mode-locked fiber laser with large normal and anomalous dispersion.

    PubMed

    Zhang, Lei; El-Damak, A R; Feng, Yan; Gu, Xijia

    2013-05-20

    An ytterbium-doped mode-locked fiber laser was demonstrated with a chirped fiber Bragg grating for dispersion management. The cavity net dispersion could be changed from large normal dispersion (2.4 ps(2)) to large anomalous dispersion (-2.0 ps(2)), depending on the direction of the chirped Bragg grating in laser cavity. The proposed fiber lasers with large normal dispersion generated stable pulses with a pulse width of <1.1 ns and a pulse energy of 1.5 nJ. The laser with large anomalous dispersion generated wavelength-tunable soliton with a pulse width of 2.7 ps and pulse energy of 0.13 nJ. A theoretical model was established and used to verify the experimental observations.

  1. Experimental and numerical studies of mode-locked fiber laser with large normal and anomalous dispersion.

    PubMed

    Zhang, Lei; El-Damak, A R; Feng, Yan; Gu, Xijia

    2013-05-20

    An ytterbium-doped mode-locked fiber laser was demonstrated with a chirped fiber Bragg grating for dispersion management. The cavity net dispersion could be changed from large normal dispersion (2.4 ps(2)) to large anomalous dispersion (-2.0 ps(2)), depending on the direction of the chirped Bragg grating in laser cavity. The proposed fiber lasers with large normal dispersion generated stable pulses with a pulse width of <1.1 ns and a pulse energy of 1.5 nJ. The laser with large anomalous dispersion generated wavelength-tunable soliton with a pulse width of 2.7 ps and pulse energy of 0.13 nJ. A theoretical model was established and used to verify the experimental observations. PMID:23736423

  2. Application of Normal Mode Expansion to AE Waves in Finite Plates

    NASA Technical Reports Server (NTRS)

    Gorman, M. R.; Prosser, W. H.

    1997-01-01

    Breckenridge et al. (1975), Hsu (1985) and Pao (1978) adapted approaches from seismology to calculate the response at the surface of an infinite half-space and an infinite plate. These approaches have found use in calibrating acoustic emission (AE) transducers. However, it is difficult to extend this theoretical approach to AE testing of practical structures. Weaver and Pao (1982) considered a normal mode solution to the Lamb equations. Hutchinson (1983) pointed out the potential relevance of Mindlin's plate theory (1951) to AE. Pao (1982) reviewed Medick s (1961) classical plate theory for a point source, but rejected it as useful for AE and no one seems to have investigated its relevance to AE any further. Herein, a normal mode solution to the classical plate bending equation was investigated for its applicability to AE. The same source-time function chosen by Weaver and Pao is considered. However, arbitrary source and receiver positions are chosen relative to the boundaries of the plate. This is another advantage of the plate theory treatment in addition to its simplicity. The source does not have to be at the center of the plate as in the axisymmetric treatment. The plate is allowed to remain finite and reflections are predicted. The importance of this theory to AE is that it can handle finite plates, realistic boundary conditions, and can be extended to composite materials.

  3. Normal modes of symmetric protein assemblies. Application to the tobacco mosaic virus protein disk.

    PubMed Central

    Simonson, T; Perahia, D

    1992-01-01

    We use group theoretical methods to study the molecular dynamics of symmetric protein multimers in the harmonic or quasiharmonic approximation. The method explicitly includes the long-range correlations between protein subunits. It can thus address collective dynamic effects, such as cooperativity between subunits. The n lowest-frequency normal modes of each individual subunit are combined into symmetry coordinates for the entire multimer. The Hessian of the potential energy is thereby reduced to a series of blocks of order n or 2n. In the quasiharmonic approximation, the covariance matrix of the atomic oscillations is reduced to the same block structure by an analogous set of symmetry coordinates. The method is applied to one layer of the tobacco mosaic virus protein disk in vacuo, to gain insight into the role of conformational fluctuations and electrostatics in tobacco mosaic virus assembly. The system has 78,000 classical, positional, degrees of freedom, yet the calculation is reduced by symmetry to a problem of order 4,600. Normal modes in the 0-100 cm-1 range were calculated. The calculated correlations extend mainly from each subunit to its nearest neighbors. The network of core helices has weak correlations with the rest of the structure. Similarly, the inner loops 90-108 are uncorrelated with the rest of the structure. Thus, the model predicts that the dielectric response in the RNA-binding region is mainly due to the loops alone. Images FIGURE 1 FIGURE 3 FIGURE 5 FIGURE 7 FIGURE 8 PMID:1547329

  4. Classification of ground states and normal modes for phase-frustrated multicomponent superconductors

    NASA Astrophysics Data System (ADS)

    Weston, Daniel; Babaev, Egor

    2013-12-01

    We classify ground states and normal modes for n-component superconductors with frustrated intercomponent Josephson couplings, focusing on n=4. The results should be relevant not only to multiband superconductors, but also to Josephson-coupled multilayers and Josephson-junction arrays. It was recently discussed that three-component superconductors can break time-reversal symmetry as a consequence of phase frustration. We discuss how to classify frustrated superconductors with an arbitrary number of components. Although already for the four-component case there are a large number of different combinations of phase-locking and phase-antilocking Josephson couplings, we establish that there are a much smaller number of equivalence classes where properties of frustrated multicomponent superconductors can be mapped to each other. This classification is related to the graph-theoretical concept of Seidel switching. Numerically, we calculate ground states, normal modes, and characteristic length scales for the four-component case. We report conditions of appearance of new accidental continuous ground-state degeneracies.

  5. Estimation of splitting functions from Earth's normal mode spectra using the neighbourhood algorithm

    NASA Astrophysics Data System (ADS)

    Pachhai, Surya; Tkalčić, Hrvoje; Masters, Guy

    2016-01-01

    The inverse problem for Earth structure from normal mode data is strongly non-linear and can be inherently non-unique. Traditionally, the inversion is linearized by taking partial derivatives of the complex spectra with respect to the model parameters (i.e. structure coefficients), and solved in an iterative fashion. This method requires that the earthquake source model is known. However, the release of energy in large earthquakes used for the analysis of Earth's normal modes is not simple. A point source approximation is often inadequate, and a more complete account of energy release at the source is required. In addition, many earthquakes are required for the solution to be insensitive to the initial constraints and regularization. In contrast to an iterative approach, the autoregressive linear inversion technique conveniently avoids the need for earthquake source parameters, but it also requires a number of events to achieve full convergence when a single event does not excite all singlets well. To build on previous improvements, we develop a technique to estimate structure coefficients (and consequently, the splitting functions) using a derivative-free parameter search, known as neighbourhood algorithm (NA). We implement an efficient forward method derived using the autoregresssion of receiver strips, and this allows us to search over a multiplicity of structure coefficients in a relatively short time. After demonstrating feasibility of the use of NA in synthetic cases, we apply it to observations of the inner core sensitive mode 13S2. The splitting function of this mode is dominated by spherical harmonic degree 2 axisymmetric structure and is consistent with the results obtained from the autoregressive linear inversion. The sensitivity analysis of multiple events confirms the importance of the Bolivia, 1994 earthquake. When this event is used in the analysis, as little as two events are sufficient to constrain the splitting functions of 13S2 mode. Apart from

  6. Comparing normal modes across different models and scales: Hessian reduction versus coarse-graining.

    PubMed

    Ghysels, An; Miller, Benjamin T; Pickard, Frank C; Brooks, Bernard R

    2012-10-30

    Dimension reduction is often necessary when attempting to reach longer length and time scales in molecular simulations. It is realized by constraining degrees of freedom or by coarse-graining the system. When evaluating the accuracy of a dimensional reduction, there is a practical challenge: the models yield vectors with different lengths, making a comparison by calculating their dot product impossible. This article investigates mapping procedures for normal mode analysis. We first review a horizontal mapping procedure for the reduced Hessian techniques, which projects out degrees of freedom. We then design a vertical mapping procedure for the "implosion" of the all-atom (AA) Hessian to a coarse-grained scale that is based upon vibrational subsystem analysis. This latter method derives both effective force constants and an effective kinetic tensor. Next, a series of metrics is presented for comparison across different scales, where special attention is given to proper mass-weighting. The dimension-dependent metrics, which require prior mapping for proper evaluation, are frequencies, overlap of normal mode vectors, probability similarity, Hessian similarity, collectivity of modes, and thermal fluctuations. The dimension-independent metrics are shape derivatives, elastic modulus, vibrational free energy differences, heat capacity, and projection on a predefined basis set. The power of these metrics to distinguish between reasonable and unreasonable models is tested on a toy alpha helix system and a globular protein; both are represented at several scales: the AA scale, a Gō-like model, a canonical elastic network model, and a network model with intentionally unphysical force constants.

  7. Broadband radiation modes: Estimation and active control

    NASA Astrophysics Data System (ADS)

    Berkhoff, Arthur P.

    2002-03-01

    In this paper we give a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce the controller dimensionality. Because these particular radiation modes are optimum in a broadband sense, they are termed broadband radiation modes. Methods are given to obtain these modes from measured data. The broadband radiation modes are used for the design of an actuator array in a feedback control system to reduce the sound power radiated from a plate. Three methods for the design of the actuator are compared, taking into account the reduction of radiated sound power in the controlled frequency range, but also the possible increase of radiated sound power in the uncontrolled frequency range.

  8. Short-Period Normal-mode Synthetics and Fr{é}chet kernels for Spherically Symmetric Earth Models

    NASA Astrophysics Data System (ADS)

    Yang, H.; Zhao, L.; Hung, S.

    2007-12-01

    Determination of three dimensional multiscale Earth structures requires high-quality seismic data and accurate synthetic waveforms. To extract and interpret the full waveform information from widely available broadband data, we need to be able to calculate complete broadband synthetic seismograms. Normal-mode theory provides the exact solutions to the wave equation in spherically symmetric Earth models, and the efficiency afforded by the usage of precalculated eigenfunction databases makes normal-mode summation the preferred approach for calculating long-period synthetic seismograms in 1-D reference models. In this study, we extend the normal-mode summation to short period by attacking the problems encountered in computing normal-mode eigenfrequencies and eigenfunctions at higher frequencies. Flexible radial sampling scheme based on the WKBJ approximation is adopted to ensure the accuracy of the secular equation when the radial eigenfunctions are highly oscillatory. This allows us to compute accurate normal-mode eigenfunctions up to much higher frequencies (~ 1Hz for Spheroidal and ~ 2Hz for Toroidal modes). Although errors can still be large for certain modes, they are almost all inner-core shear modes, and numerical experiments show that they have no contribution to seismograms on the surface. In contrast, omitting only 0.1% mantle modes at random can lead to noisy synthetics. The capability to compute normal modes up to high frequencies enables us to obtain accurate and complete synthetic seismograms that can be used to both extract waveform information from all seismic phases and to compute their full-wave Fr{é}chet kernels, which opens up possibilities in global and regional high-resolution tomography as well as studies on the seismic structure in the deep mantle and the inner core.

  9. Optogenetic Activation of Normalization in Alert Macaque Visual Cortex.

    PubMed

    Nassi, Jonathan J; Avery, Michael C; Cetin, Ali H; Roe, Anna W; Reynolds, John H

    2015-06-17

    Normalization has been proposed as a canonical computation that accounts for a variety of nonlinear neuronal response properties associated with sensory processing and higher cognitive functions. A key premise of normalization is that the excitability of a neuron is inversely proportional to the overall activity level of the network. We tested this by optogenetically activating excitatory neurons in alert macaque primary visual cortex and measuring changes in neuronal activity as a function of stimulation intensity, with or without variable-contrast visual stimulation. Optogenetic depolarization of excitatory neurons either facilitated or suppressed baseline activity, consistent with indirect recruitment of inhibitory networks. As predicted by the normalization model, neurons exhibited sub-additive responses to optogenetic and visual stimulation, which depended lawfully on stimulation intensity and luminance contrast. We conclude that the normalization computation persists even under the artificial conditions of optogenetic stimulation, underscoring the canonical nature of this form of neural computation.

  10. Optogenetic Activation of Normalization in Alert Macaque Visual Cortex.

    PubMed

    Nassi, Jonathan J; Avery, Michael C; Cetin, Ali H; Roe, Anna W; Reynolds, John H

    2015-06-17

    Normalization has been proposed as a canonical computation that accounts for a variety of nonlinear neuronal response properties associated with sensory processing and higher cognitive functions. A key premise of normalization is that the excitability of a neuron is inversely proportional to the overall activity level of the network. We tested this by optogenetically activating excitatory neurons in alert macaque primary visual cortex and measuring changes in neuronal activity as a function of stimulation intensity, with or without variable-contrast visual stimulation. Optogenetic depolarization of excitatory neurons either facilitated or suppressed baseline activity, consistent with indirect recruitment of inhibitory networks. As predicted by the normalization model, neurons exhibited sub-additive responses to optogenetic and visual stimulation, which depended lawfully on stimulation intensity and luminance contrast. We conclude that the normalization computation persists even under the artificial conditions of optogenetic stimulation, underscoring the canonical nature of this form of neural computation. PMID:26087167

  11. Possibility of observation of polaron normal modes at the far-infrared spectrum of acetanilide and related organics

    NASA Astrophysics Data System (ADS)

    Kalosakas, G.; Aubry, S.; Tsironis, G. P.

    1998-10-01

    We use a stationary and normal mode analysis of the semiclassical Holstein model in order to connect the low-frequency linear polaron modes to low-lying far-infrared lines of the acetanilide spectrum and through parameter fitting we comment on the validity of the polaron results in this system.

  12. Computational modes and the Machenauer N.L.N.M.I. of the GLAS 4th order model. [NonLinear Normal Mode Initialization in numerical weather forecasting

    NASA Technical Reports Server (NTRS)

    Navon, I. M.; Bloom, S.; Takacs, L. L.

    1985-01-01

    An attempt was made to use the GLAS global 4th order shallow water equations to perform a Machenhauer nonlinear normal mode initialization (NLNMI) for the external vertical mode. A new algorithm was defined for identifying and filtering out computational modes which affect the convergence of the Machenhauer iterative procedure. The computational modes and zonal waves were linearly initialized and gravitational modes were nonlinearly initialized. The Machenhauer NLNMI was insensitive to the absence of high zonal wave numbers. The effects of the Machenhauer scheme were evaluated by performing 24 hr integrations with nondissipative and dissipative explicit time integration models. The NLNMI was found to be inferior to the Rasch (1984) pseudo-secant technique for obtaining convergence when the time scales of nonlinear forcing were much smaller than the time scales expected from the natural frequency of the mode.

  13. Dynamics and instantaneous normal modes in a liquid with density anomalies.

    PubMed

    Ciamarra, M P; Sollich, P

    2015-05-20

    We investigate the relation between the dynamical features of a supercooled liquid and those of its potential energy landscape, focusing on a model liquid with density anomalies. We consider, at fixed temperature, pairs of state points with different density but the same diffusion constant and find that surprisingly they have identical dynamical features at all length and time scales. This is shown by the collapse of their mean square displacements and of their self-intermediate scattering functions at different wavevectors. We then investigate how the features of the energy landscape change with density and establish that state points with equal diffusion constant have different landscapes. In particular, we find a correlation between the fraction of instantaneous normal modes connecting different energy minima and the diffusion constant, but unlike in other systems these two quantities are not in one-to-one correspondence with each other, showing that additional landscape features must be relevant in determining the diffusion constant.

  14. Regional variation of inner core anisotropy from seismic normal mode observations.

    PubMed

    Deuss, Arwen; Irving, Jessica C E; Woodhouse, John H

    2010-05-21

    Earth's solid inner core is surrounded by a convecting liquid outer core, creating the geodynamo driving the planet's magnetic field. Seismic studies using compressional body waves suggest hemispherical variation in the anisotropic structure of the inner core, but are poorly constrained because of limited earthquake and receiver distribution. Here, using normal mode splitting function measurements from large earthquakes, based on extended cross-coupling theory, we observe both regional variations and eastern versus western hemispherical anisotropy in the inner core. The similarity of this pattern with Earth's magnetic field suggests freezing-in of crystal alignment during solidification or texturing by Maxwell stress as origins of the anisotropy. These observations limit the amount of inner core super rotation, but would be consistent with oscillation. PMID:20395476

  15. Regional variation of inner core anisotropy from seismic normal mode observations.

    PubMed

    Deuss, Arwen; Irving, Jessica C E; Woodhouse, John H

    2010-05-21

    Earth's solid inner core is surrounded by a convecting liquid outer core, creating the geodynamo driving the planet's magnetic field. Seismic studies using compressional body waves suggest hemispherical variation in the anisotropic structure of the inner core, but are poorly constrained because of limited earthquake and receiver distribution. Here, using normal mode splitting function measurements from large earthquakes, based on extended cross-coupling theory, we observe both regional variations and eastern versus western hemispherical anisotropy in the inner core. The similarity of this pattern with Earth's magnetic field suggests freezing-in of crystal alignment during solidification or texturing by Maxwell stress as origins of the anisotropy. These observations limit the amount of inner core super rotation, but would be consistent with oscillation.

  16. Robust normal mode constraints on inner-core anisotropy from model space search.

    PubMed

    Beghein, Caroline; Trampert, Jeannot

    2003-01-24

    A technique for searching full model space that was applied to measurements of anomalously split normal modes showed a robust pattern of P-wave and S-wave anisotropy in the inner core. The parameter describing P-wave anisotropy changes sign around a radius of 400 kilometers, whereas S-wave anisotropy is small in the upper two-thirds of the inner core and becomes negative at greater depths. Our results agree with observed travel-time anomalies of rays traveling at epicentral distances varying from 150 degrees to 180 degrees. The models may be explained by progressively tilted hexagonal close-packed iron in the upper half of the inner core and could suggest a different iron phase in the center.

  17. Streaky noise in seismic normal mode band observed at Syowa Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Hayakawa, H.; Shibuya, K.; Doi, K.; Aoyama, Y.

    2010-12-01

    Background free oscillations are known as continuous and global signals on noise level in seismic normal mode band. These were found from record of superconducting gravimeter (SG) at Syowa Station, Antarctica in 1998 [Nawa et al. 1998], and then were confirmed at various sites. Other unknown slightly broad spectrum peaks were also found as streak on spectrogram of Syowa SG data in seismic normal mode band. But the feature is not found in gravimeter and seismometer records from any other sites, including IDA gravimeter record at SPA station, Antarctica. New SG (SG058), that is the third generation at Syowa Station, has started to observe since January 2010. The second generation SG (CT43, 2004-2009) had strong drift. The auxiliary barometer was less resolution (0.1 hPa) and its pressure record had a lot of steps and spikes occurring frequently by housing problem. To study in seismic normal mode band, high quality pressure data is needed to remove atmospheric pressure effect to gravity from SG data because a nominal admittance factor for its effect is -3 nm/s^2/hPa. The new barometer of SG058 system has a resolution of 0.001 hPa, and the housing problem has been fixed. In this study, we investigated the unknown streaky noise in seismic normal mode band using spectrograms of the new SG and other data observed at Syowa Station. The slightly broad spectrum peaks are clearly found at 2.5, 3.5, 7.6, 8.2 13.2, 16.7 mHz from the SG data during January - May 2010. Strength of these peaks shows time variation and it is not necessarily for phase to agree with each others. These unknown peaks are not intrinsic noise of the first generation SG (TT70, 1993 - 2003) but are local or regional signal (noise) around Syowa Station. The atmospheric pressure doesn’t have this steaky feature. The sea level variation causes noise level of Syowa SG data to be high by the effect of attraction and loading [Nawa et al. 2003]. Because the noise spectral peaks less than 3 mHz are removed by

  18. Normal mode analysis of single bunch, charge density dependent behavior in electron/positron beams

    NASA Astrophysics Data System (ADS)

    Ehrlichman, Michael

    Accelerator science in coming years will be increasingly dependent upon high single-bunch charges and/or small emittances. Under these conditions, single-particle dynamics are not a sufficient description of beam behavior and interactions between the beam particles must be taken into account. One such interaction is when collisions between the particles that compose a bunch perturb the motion of the colliding particles significantly and frequently enough to impact the beam dynamics. Multiple, small-angle, collisions blow up the emittance of the bunch and are referred to as intrabeam scattering (IBS). Here are documented the theoretical and experimental studies of IBS in storage rings undertaken as part of the CesrTA program. Under the conditions where IBS becomes dominant, other multi-particle effects can also appear. The additional effects we investigate include potential well distortion, coherent current-dependent tune shift, and direct space charge. CesrTA design and analysis is conducted in a normal mode coordinates environment which allows for natural handling of coupling. To that end, we develop a 6D normal modes decomposition of the linear beam optics. Multi-particle effects are also important for Energy Recovery Linear Accelerators (ERLs). Because the beam circulates for only a short period of time in an ERL, the beam lifetime imposed by Touschek scattering is not significant. However, the particles scattered out of the bunch can generate a radiation hazard where they collide with the beam pipe. We re-derive Piwinski's original Touschek scattering equation to check its validity when applied to ERL beams, then repurpose the formula to generate a profile of where scattered particles are generated and where they are lost. The results presented here advance our understanding of charge-dependent behavior in the sorts of high charge-density accelerators that will be implemented in coming years.

  19. Normal modes of 4-aminobenzonitrile (4-ABN). A comparison of PM3 calculations with experimental jet-cooled spectroscopy

    NASA Astrophysics Data System (ADS)

    Yu, Haiping; Joslin, Evelyn; Zain, Sharifuddin M.; Rzepa, Henry; Phillips, David

    1993-12-01

    The geometry and the normal modes of 4-aminobenzonitrile (4-ABN) in the ground and first excited states have been computed using PM3 formulation. These calculated results, together with previous vapour phase absorption and infrared studies, are used to examine the vibrational modes in the laser-induced fluorescence (LIF) excitation and emission spectra of jet-cooled 4-ABN. The calculated vibrational frequencies of the normal modes show good agreement with experiment both for the electronic ground and the first excited states, but there is a relatively large discrepancy in the position of the electronic origin transition.

  20. Normal modes for large molecules with arbitrary link constraints in the mobile block Hessian approach

    NASA Astrophysics Data System (ADS)

    Ghysels, A.; Van Neck, D.; Brooks, B. R.; Van Speybroeck, V.; Waroquier, M.

    2009-02-01

    In a previous paper [Ghysels et al., J. Chem. Phys. 126, 224102 (2007)] the mobile block Hessian (MBH) approach was presented. The method was designed to accurately compute vibrational modes of partially optimized molecular structures. The key concept was the introduction of several blocks of atoms, which can move as rigid bodies with respect to a local, fully optimized subsystem. The choice of the blocks was restricted in the sense that none of them could be connected, and also linear blocks were not taken into consideration. In this paper an extended version of the MBH method is presented that is generally applicable and allows blocks to be adjoined by one or two common atoms. This extension to all possible block partitions of the molecule provides a structural flexibility varying from very rigid to extremely relaxed. The general MBH method is very well suited to study selected normal modes of large macromolecules (such as proteins and polymers) because the number of degrees of freedom can be greatly reduced while still keeping the essential motions of the molecular system. The reduction in the number of degrees of freedom due to the block linkages is imposed here directly using a constraint method, in contrast to restraint methods where stiff harmonic couplings are introduced to restrain the relative motion of the blocks. The computational cost of this constraint method is less than that of an implementation using a restraint method. This is illustrated for the α-helix conformation of an alanine-20-polypeptide.

  1. Normal Mode Analysis in Zeolites: Toward an Efficient Calculation of Adsorption Entropies.

    PubMed

    De Moor, Bart A; Ghysels, An; Reyniers, Marie-Françoise; Van Speybroeck, Veronique; Waroquier, Michel; Marin, Guy B

    2011-04-12

    An efficient procedure for normal-mode analysis of extended systems, such as zeolites, is developed and illustrated for the physisorption and chemisorption of n-octane and isobutene in H-ZSM-22 and H-FAU using periodic DFT calculations employing the Vienna Ab Initio Simulation Package. Physisorption and chemisorption entropies resulting from partial Hessian vibrational analysis (PHVA) differ at most 10 J mol(-1) K(-1) from those resulting from full Hessian vibrational analysis, even for PHVA schemes in which only a very limited number of atoms are considered free. To acquire a well-conditioned Hessian, much tighter optimization criteria than commonly used for electronic energy calculations in zeolites are required, i.e., at least an energy cutoff of 400 eV, maximum force of 0.02 eV/Å, and self-consistent field loop convergence criteria of 10(-8) eV. For loosely bonded complexes the mobile adsorbate method is applied, in which frequency contributions originating from translational or rotational motions of the adsorbate are removed from the total partition function and replaced by free translational and/or rotational contributions. The frequencies corresponding with these translational and rotational modes can be selected unambiguously based on a mobile block Hessian-PHVA calculation, allowing the prediction of physisorption entropies within an accuracy of 10-15 J mol(-1) K(-1) as compared to experimental values. The approach presented in this study is useful for studies on other extended catalytic systems.

  2. Notch strengthening or weakening governed by transition of shear failure to normal mode fracture

    PubMed Central

    Lei, Xianqi; Li, Congling; Shi, Xinghua; Xu, Xianghong; Wei, Yujie

    2015-01-01

    It is generally observed that the existence of geometrical discontinuity like notches in materials will lead to strength weakening, as a resultant of local stress concentration. By comparing the influence of notches to the strength of three typical materials, aluminum alloys with intermediate tensile ductility, metallic glasses with no tensile ductility, and brittle ceramics, we observed strengthening in aluminum alloys and metallic glasses: Tensile strength of the net section in circumferentially notched cylinders increases with the constraint quantified by the ratio of notch depth over notch root radius; in contrast, the ceramic exhibit notch weakening. The strengthening in the former two is due to resultant deformation transition: Shear failure occurs in intact samples while samples with deep notches break in normal mode fracture. No such deformation transition was observed in the ceramic, and stress concentration leads to its notch weakening. The experimental results are confirmed by theoretical analyses and numerical simulation. The results reported here suggest that the conventional criterion to use brittleness and/or ductility to differentiate notch strengthening or weakening is not physically sound. Notch strengthening or weakening relies on the existence of failure mode transition and materials exhibiting shear failure while subjected to tension will notch strengthen. PMID:26022892

  3. Normal Mode Analysis in Zeolites: Toward an Efficient Calculation of Adsorption Entropies.

    PubMed

    De Moor, Bart A; Ghysels, An; Reyniers, Marie-Françoise; Van Speybroeck, Veronique; Waroquier, Michel; Marin, Guy B

    2011-04-12

    An efficient procedure for normal-mode analysis of extended systems, such as zeolites, is developed and illustrated for the physisorption and chemisorption of n-octane and isobutene in H-ZSM-22 and H-FAU using periodic DFT calculations employing the Vienna Ab Initio Simulation Package. Physisorption and chemisorption entropies resulting from partial Hessian vibrational analysis (PHVA) differ at most 10 J mol(-1) K(-1) from those resulting from full Hessian vibrational analysis, even for PHVA schemes in which only a very limited number of atoms are considered free. To acquire a well-conditioned Hessian, much tighter optimization criteria than commonly used for electronic energy calculations in zeolites are required, i.e., at least an energy cutoff of 400 eV, maximum force of 0.02 eV/Å, and self-consistent field loop convergence criteria of 10(-8) eV. For loosely bonded complexes the mobile adsorbate method is applied, in which frequency contributions originating from translational or rotational motions of the adsorbate are removed from the total partition function and replaced by free translational and/or rotational contributions. The frequencies corresponding with these translational and rotational modes can be selected unambiguously based on a mobile block Hessian-PHVA calculation, allowing the prediction of physisorption entropies within an accuracy of 10-15 J mol(-1) K(-1) as compared to experimental values. The approach presented in this study is useful for studies on other extended catalytic systems. PMID:26606357

  4. Bayesian normal modes identification and estimation of elastic coefficients in resonant ultrasound spectroscopy

    NASA Astrophysics Data System (ADS)

    Bernard, Simon; Marrelec, Guillaume; Laugier, Pascal; Grimal, Quentin

    2015-06-01

    Resonant ultrasound spectroscopy is an experimental technique for measuring the stiffness of anisotropic solid materials. The free vibration resonant frequencies of a specimen are measured and the stiffness coefficients of the material adjusted to minimize the difference between experimental and predicted frequencies. An issue of this inverse approach is that the measured frequencies are not easily paired with their predicted counterpart, leading to ambiguities in the definition of the objective function. In the past, this issue has been overcome through trial-and-error methods requiring the experimentalist to find the correct pairing, or through involved experimental methods measuring the shapes of the normal vibration modes in addition to their frequencies. The purpose of this work is to show, through a Bayesian formulation, that the inverse problem can be solved automatically and without requiring additions to the usual experimental setup. The pairing of measured and predicted frequencies is considered unknown, and the joint posterior probability distribution of pairing and stiffness is sampled using Markov chain Monte Carlo. The method is illustrated on two published data sets. The first set includes the exact pairing, allowing validation of the method. The second application deals with attenuative materials, for which many predicted modes cannot be observed, further complicating the inverse problem. In that case, introduction of prior information through Bayesian formulation reduces ambiguities.

  5. Instantaneous normal mode prediction for cation and anion diffusion in ionic melts

    NASA Astrophysics Data System (ADS)

    Ribeiro, M. C. C.; Madden, P. A.

    1997-05-01

    Instantaneous normal mode (INM) analysis was undertaken for several ionic melts: NaCl at six distinct thermodynamic states, and for a particular state of liquid LiCl, LiF, KF, KI, NaI, ZnCl2, and CuCl. In this Communication, we show that, in most cases, the ratio between the diffusion constants for cations (Dca) and anions (Dan) is predicted from the average frequency of the real ("stable" <ωs>) and imaginary ("unstable" <ωu>) frequency modes of the projection of the total density of states on cations and anions, respectively. The proposed relationship, Dca/Dan=(mca-1<ωu>ca<ωs>ca-2)ṡ(man-1<ωu>an<ωs>an-2)-1, where mi is the mass of a particular species, is suggested by Keyes' INM theory for diffusion [J. Chem. Phys. 101, 5081 (1994)], with the further assumption that the parameters which are related to the topology of the multidimensional potential surface are equal for cations and anions. The above equation is shown to be valid for the simple melts NaCl, LiCl, LiF, KF, KI, and NaI, but to fail for the network forming melt ZnCl2 and for CuCl, which shows fast ionic diffusion characteristics.

  6. Constructing the frequency and wave normal distribution of whistler-mode wave power

    NASA Astrophysics Data System (ADS)

    Watt, C. E. J.; Degeling, A. W.; Rankin, R.

    2013-05-01

    We introduce a new methodology that allows the construction of wave frequency distributions due to growing incoherent whistler-mode waves in the magnetosphere. The technique combines the equations of geometric optics (i.e., raytracing) with the equation of transfer of radiation in an anisotropic lossy medium to obtain spectral energy density as a function of frequency and wavenormal angle. We describe the method in detail and then demonstrate how it could be used in an idealized magnetosphere during quiet geomagnetic conditions. For a specific set of plasma conditions, we predict that the wave power peaks off the equator at ˜15° magnetic latitude. The new calculations predict that wave power as a function of frequency can be adequately described using a Gaussian function, but as a function of wavenormal angle, it more closely resembles a skew normal distribution. The technique described in this paper is the first known estimate of the parallel and oblique incoherent wave spectrum as a result of growing whistler-mode waves and provides a means to incorporate self-consistent wave-particle interactions in a kinetic model of the magnetosphere over a large volume.

  7. Measurement of nonlinear normal modes using multi-harmonic stepped force appropriation and free decay

    NASA Astrophysics Data System (ADS)

    Ehrhardt, David A.; Allen, Matthew S.

    2016-08-01

    Nonlinear Normal Modes (NNMs) offer tremendous insight into the dynamic behavior of a nonlinear system, extending many concepts that are familiar in linear modal analysis. Hence there is interest in developing methods to experimentally and numerically determine a system's NNMs for model updating or simply to characterize its dynamic response. Previous experimental work has shown that a mono-harmonic excitation can be used to isolate a system's dynamic response in the neighborhood of a NNM along the main backbones of a system. This work shows that a multi-harmonic excitation is needed to isolate a NNM when well separated linear modes of a structure couple to produce an internal resonance. It is shown that one can tune the multiple harmonics of the input excitation using a plot of the input force versus the response velocity until the area enclosed by the force-velocity curve is minimized. Once an appropriated NNM is measured, one can increase the force level and retune the frequency to obtain a NNM at a higher amplitude or remove the excitation and measure the structure's decay down a NNM backbone. This work explores both methods using simulations and measurements of a nominally-flat clamped-clamped beam excited at a single point with a magnetic force. Numerical simulations are used to validate the method in a well defined environment and to provide comparison with the experimentally measured NNMs. The experimental results seem to produce a good estimate of two NNMs along their backbone and part of an internal resonance branch. Full-field measurements are then used to further explore the couplings between the underlying linear modes along the identified NNMs.

  8. High-energy square pulses and burst-mode pulses in an all-normal dispersion double-clad mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Qiao, Zhi; Wang, Xiaochao; Wang, Chao; Jing, Yuanyuan; Fan, Wei; Lin, Zunqi

    2016-05-01

    A double-clad Yb-doped mode-locked fiber laser that can operate in burst-mode and square-pulse states is experimentally investigated. In the burst-mode state, a burst train with 55 pulses of 500 ps duration is obtained. In the square-pulse state, which is similar to noiselike pulses, the maximum pulse energy is 820 nJ and the duration can be tuned from 15.8 to 546 ns. The square pulses have a narrow and multipeak spectrum, which is quite different from that of normal noiselike pulses. The fiber laser promises an alternative formation mechanism for burst-mode and square-pulse mode-locked fiber lasers.

  9. Serum gamma-glutamyl transpeptidase activity in normal children.

    PubMed

    Shore, G M; Hoberman, L; Dowdey, B C; Combes, B

    1975-02-01

    Serum gamma-glutamyl transpeptidase (GGT) activities of 82 healthy neonates (aged 9 hours to 11 days) and 106 healthy children (aged 2 months to 15 years) were determined. Serum GGT activity of 47 neonates (51%) was higher than the accepted upper limit of normal for adults. By three months of age, all of the children had serum GGT activities that were within the accepted normal range for adults. Thereafter there was only minimal variation in serum GGT activities of older children. Although mean serum GGT activity was higher in male children than in female children, there was no significant difference between the values for male and female neonates. That after the neonatal period serum GGT activity is constant in the adult range and is not affected by bone growth as is alkaline phosphatase suggests that GGT may be of value in the evaluation of hepatobiliary disease in children.

  10. A New Non-linear Technique for Measurement of Splitting Functions of Normal Modes of the Earth

    NASA Astrophysics Data System (ADS)

    Pachhai, S.; Masters, G.; Tkalcic, H.

    2014-12-01

    Normal modes are the vibrating patterns of the Earth in response to the large earthquakes. Normal mode spectra are split due to Earth's rotation, ellipticity, and heterogeneity. The normal mode splitting is visualized through splitting functions, which represent the local radial average of Earth's structure seen by a mode of vibration. The analysis of the splitting of normal modes can provide unique information about the lateral variation of the Earth's elastic properties that cannot be directly imaged in body wave tomographic images. The non-linear iterative spectral fitting of the observed complex spectra and autoregressive linear inversion have been widely utilized to compute the Earth's 3-D structure. However, the non-linear inversion requires a model of the earthquake source and the retrieved 3-D structure is sensitive to the initial constraints. In contrast, the autoregressive linear inversion does not require the source model. However, this method requires many events to achieve full convergence. In addition, significant disagreement exists between different studies because of the non-uniqueness of the problem and limitations of different methods. We thus apply the neighbourhood algorithm (NA) to measure splitting functions. The NA is an efficient model space search technique and works in two steps: In the first step, the algorithm finds all the models compatible with given data while the posterior probability density of the model parameters are obtained in the second step. The NA can address the problem of non-uniqueness by taking advantage of random sampling of the full model space. The parameter trade-offs are conveniently visualized using joint marginal distributions. In addition, structure coefficients uncertainties can be extracted from the posterior probability distribution. After demonstrating the feasibility of NA with synthetic examples, we compute the splitting functions for the mode 13S2 (sensitive to the inner core) from several large

  11. On the normal modes of Laplace's tidal equations for zonal wavenumber zero

    NASA Technical Reports Server (NTRS)

    Tanaka, H. L.; Kasahara, Akira

    1992-01-01

    The characteristic differences between two different rotational modes of Laplace's tidal equations for wavenumber m = 0, called the K- and the S-modes, are compared in their energy ratio and structures. It is shown that the K-mode representation captures most of the observed zonal energy with a few terms, whereas the S-mode representation requires many terms. For small vertical scale components, the K-mode series converges faster than the S-mode series. Attention is also given to the differences between the energy spectra projected upon the K- and S-modes and the merits of each set as expansion functions for the zonal atmospheric motions.

  12. Dynamic elastic moduli in magnetic gels: Normal modes and linear response.

    PubMed

    Pessot, Giorgio; Löwen, Hartmut; Menzel, Andreas M

    2016-09-14

    In the perspective of developing smart hybrid materials with customized features, ferrogels and magnetorheological elastomers allow a synergy of elasticity and magnetism. The interplay between elastic and magnetic properties gives rise to a unique reversible control of the material behavior by applying an external magnetic field. Albeit few works have been performed on the time-dependent properties so far, understanding the dynamic behavior is the key to model many practical situations, e.g., applications as vibration absorbers. Here we present a way to calculate the frequency-dependent elastic moduli based on the decomposition of the linear response to an external stress in normal modes. We use a minimal three-dimensional dipole-spring model to theoretically describe the magnetic and elastic interactions on the mesoscopic level. Specifically, the magnetic particles carry permanent magnetic dipole moments and are spatially arranged in a prescribed way, before they are linked by elastic springs. An external magnetic field aligns the magnetic moments. On the one hand, we study regular lattice-like particle arrangements to compare with previous results in the literature. On the other hand, we calculate the dynamic elastic moduli for irregular, more realistic particle distributions. Our approach measures the tunability of the linear dynamic response as a function of the particle arrangement, the system orientation with respect to the external magnetic field, as well as the magnitude of the magnetic interaction between the particles. The strength of the present approach is that it explicitly connects the relaxational modes of the system with the rheological properties as well as with the internal rearrangement of the particles in the sample, providing new insight into the dynamics of these remarkable materials. PMID:27634276

  13. Dynamic elastic moduli in magnetic gels: Normal modes and linear response

    NASA Astrophysics Data System (ADS)

    Pessot, Giorgio; Löwen, Hartmut; Menzel, Andreas M.

    2016-09-01

    In the perspective of developing smart hybrid materials with customized features, ferrogels and magnetorheological elastomers allow a synergy of elasticity and magnetism. The interplay between elastic and magnetic properties gives rise to a unique reversible control of the material behavior by applying an external magnetic field. Albeit few works have been performed on the time-dependent properties so far, understanding the dynamic behavior is the key to model many practical situations, e.g., applications as vibration absorbers. Here we present a way to calculate the frequency-dependent elastic moduli based on the decomposition of the linear response to an external stress in normal modes. We use a minimal three-dimensional dipole-spring model to theoretically describe the magnetic and elastic interactions on the mesoscopic level. Specifically, the magnetic particles carry permanent magnetic dipole moments and are spatially arranged in a prescribed way, before they are linked by elastic springs. An external magnetic field aligns the magnetic moments. On the one hand, we study regular lattice-like particle arrangements to compare with previous results in the literature. On the other hand, we calculate the dynamic elastic moduli for irregular, more realistic particle distributions. Our approach measures the tunability of the linear dynamic response as a function of the particle arrangement, the system orientation with respect to the external magnetic field, as well as the magnitude of the magnetic interaction between the particles. The strength of the present approach is that it explicitly connects the relaxational modes of the system with the rheological properties as well as with the internal rearrangement of the particles in the sample, providing new insight into the dynamics of these remarkable materials.

  14. Estimation of Radiated Energy of Recent Great Earthquakes Using the Normal-mode Theory

    NASA Astrophysics Data System (ADS)

    Rivera, L. A.; Kanamori, H.

    2014-12-01

    Despite its fundamental importance in seismology, accurate estimation of radiated energy remains challenging. The interaction of the elastic field with the near-source structure, especially the free surface, makes the radiation field very complex. Here we address this problem using the normal-mode theory. Radiated energy estimations require a detailed finite source model for the spatial and temporal slip distribution. We use the slip models for recent great earthquakes provided by various investigators. We place a slip model in a spherically symmetric Earth (PREM), and compute the radiated energy by modal summation. For each mode, the volume integral of the energy density over the Earth's volume can be obtained analytically. The final expression involves a sum over the source patches nested in the modal summation itself. In practice we perform modal summation up to 80 mHz. We explore the effect of several factors such as the focal mechanism, the source depth, the source duration, the source directivity and the seismic moment. Not surprisingly, the source depth plays a key role. The effect can be very significant for events presenting large slip at shallow depths. Deep earthquakes and strike-slip earthquakes are essentially unaffected by the free surface. Similar to the situation in moment tensor determinations, shallow dipping reverse or normal focal mechanisms can be heavily affected. The preliminary estimates of the radiated energy for the frequency ≤ 80 mHz are; the 2004 Sumatra earthquake, 8.3x1016 J (average for 2 rupture models), the 2010 Maule, 1.6x1017 J (2), the 2011 Tohoku-oki, 1.1x1017 J (5), the 2012 Sumatra, 2.4x1017 J (2), the 1994 Bolivia, 4.1x1015 J (1), the 2013 Okhotsk, 2.0x1016 J (1), and the 2010 Mentawai, 2.9x1014 J (1). To obtain the total radiated energy, the radiated energy for frequency ≥ 80 mHz estimated with other methods (e.g., integration of velocity records) needs to be added.

  15. Kelvin waves: a comparison study between SABER and normal mode analysis of ECMWF data

    NASA Astrophysics Data System (ADS)

    Blaauw, Marten; Garcia, Rolando; Zagar, Nedjeljka; Tribbia, Joe

    2014-05-01

    Equatorial Kelvin waves spectra are sensitive to the multi-scale variability of their source of tropical convective forcing. Moreover, Kelvin wave spectra are modified upward by changes in the background winds and stability. Recent high resolution data from observations as well as analyses are capable of resolving the slower Kelvin waves with shorter vertical wavelength near the tropical tropopause. In this presentation, results from a quantitive comparison study of stratospheric Kelvin waves in satellite data (SABER) and analysis data from the ECMWF operational archive will be shown. Temperature data from SABER is extracted over a six year period (2007-2012) with an effective vertical resolution of 2 km. Spectral power of stratospheric Kelvin waves in SABER data is isolated by selecting symmetric and eastward spectral components in the 8-20 days range. Global data from ECMWF operational analysis is extracted for the same six years on 91 model levels (top level at 0.01 hPa) and 25 km horizontal resolution. Using three-dimensional orthogonal normal-mode expansions, the input mass and wind data from ECMWF is projected onto balanced rotational modes and unbalanced inertia-gravity modes, including spectral data for pure Kelvin waves. The results show good agreement between Kelvin waves in SABER and ECMWF analyses data for: (i) the frequency shift of Kelvin wave variance with height and (ii) vertical wavelengths. Variability with respect to QBO will also be discussed. In a previous study, discrepancies in the upper stratosphere were found to be 60% and are found here to be 10% (8-20 day averaged value), which can be explained by the better stratosphere representation in the 91 model level version of the ECMWF operational model. New discrepancies in Kelvin wave variance are found in the lower stratosphere at 20 km. Averaged spectral power over the 8-20 day range is found to be 35% higher in ECMWF compared to SABER data. We compared results at 20 km with additional

  16. Wave normal angles of whistler mode chorus rising and falling tones

    NASA Astrophysics Data System (ADS)

    Taubenschuss, Ulrich; Khotyaintsev, Yuri V.; Santolík, Ondrej; Vaivads, Andris; Cully, Christopher M.; Contel, Olivier Le; Angelopoulos, Vassilis

    2014-12-01

    We present a study of wave normal angles (θk) of whistler mode chorus emission as observed by Time History of Events and Macroscale Interactions during Substorms (THEMIS) during the year 2008. The three inner THEMIS satellites THA, THD, and THE usually orbit Earth close to the dipole magnetic equator (±20°), covering a large range of L shells from the plasmasphere out to the magnetopause. Waveform measurements of electric and magnetic fields enable a detailed polarization analysis of chorus below 4 kHz. When displayed in a frequency-θk histogram, four characteristic regions of occurrence are evident. They are separated by gaps at f/fc,e≈0.5 (f is the chorus frequency, fc,e is the local electron cyclotron frequency) and at θk˜40°. Below θk˜40°, the average value for θk is predominantly field aligned, but slightly increasing with frequency toward half of fc,e (θk up to 20°). Above half of fc,e, the average θk is again decreasing with frequency. Above θk˜40°, wave normal angles are usually close to the resonance cone angle. Furthermore, we present a detailed comparison of electric and magnetic fields of chorus rising and falling tones. Falling tones exhibit peaks in occurrence solely for θk>40° and are propagating close to the resonance cone angle. Nevertheless, when comparing rising tones to falling tones at θk>40°, the ratio of magnetic to electric field shows no significant differences. Thus, we conclude that falling tones are generated under similar conditions as rising tones, with common source regions close to the magnetic equatorial plane.

  17. Vertical normal modes of a mesoscale model using a scaled height coordinate

    NASA Technical Reports Server (NTRS)

    Lipton, A. E.; Pielke, R. A.

    1986-01-01

    Vertical modes were derived for a version of the Colorado State Regional Atmospheric Mesoscale Modeling System. The impacts of three options for dealing with the upper boundary of the model were studied. The standard model formulation holds pressure constant at a fixed altitude near the model top, and produces a fastest mode with a speed of about 90 m/sec. An alternative formulation, which allows for an external mode, could require recomputation of vertical modes for every surface elevation on the horizontal grid unless the modes are derived in a particular way. These results have bearing on the feasibility of applying vertical mode initialization to models with scaled height coordinates.

  18. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view

    SciTech Connect

    Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

    2013-11-28

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

  19. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view.

    PubMed

    Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

    2013-11-28

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

  20. REACH Coarse-Grained Normal Mode Analysis of Protein Dimer Interaction Dynamics

    PubMed Central

    Moritsugu, Kei; Kurkal-Siebert, Vandana; Smith, Jeremy C.

    2009-01-01

    Abstract The REACH (realistic extension algorithm via covariance Hessian) coarse-grained biomolecular simulation method is a self-consistent multiscale approach directly mapping atomistic molecular dynamics simulation results onto a residue-scale model. Here, REACH is applied to calculate the dynamics of protein-protein interactions. The intra- and intermolecular fluctuations and the intermolecular vibrational densities of states derived from atomistic molecular dynamics are well reproduced by the REACH normal modes. The phonon dispersion relations derived from the REACH lattice dynamics model of crystalline ribonuclease A are also in satisfactory agreement with the corresponding all-atom results. The REACH model demonstrates that increasing dimer interaction strength decreases the translational and rotational intermolecular vibrational amplitudes, while their vibrational frequencies are relatively unaffected. A comparative study of functionally interacting biological dimers with crystal dimers, which are formed artificially via crystallization, reveals a relation between their static structures and the interprotein dynamics: i.e., the consequence of the extensive interfaces of biological dimers is reduction of the intermonomer translational and rotational amplitudes, but not the frequencies. PMID:19686664

  1. Search for solar normal modes in low-frequency seismic spectra

    NASA Astrophysics Data System (ADS)

    Caton, Ross C.

    We use seismic array processing methods to attempt to enhance very low frequency harmonic signals (0-400 microhertz, also ?Hz or uHz) recorded on broadband seismic arrays. Since the discovery of this phenomenon in the 1990s, harmonic signals at these very low frequencies have come to be known as the Earth's "hum." A number of hypotheses have been suggested for the Earth's hum, including forcing by atmospheric turbulence, ocean waves, and, most recently, the Sun. We test the solar hypothesis by searching for statistically significant harmonic lines that correlate with independently observed solar free oscillations. The solar model assumes that free oscillations of the sun modulate the solar wind, producing pure harmonic components of Earth's magnetic field that are postulated to couple to the ground by electromagnetic induction. In this thesis we search the multitaper spectrum of stacks of seismic instruments for solar normal frequencies. We use a median stack instead of the more conventional mean because a more robust estimate of center is required for these low signal-to-noise data with occasional transients. A key advantage of a stack is that data gaps are easily ignored when computing the beam. Results from a stack of 18 Transportable Array stations show multiple possible g-mode detections at the 95-99% confidence level. We are presently applying this method to data from the Homestake Mine array, and may also do so with data from a broadband borehole array currently operating at Pinon Flats, California.

  2. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

    2013-11-01

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

  3. Spherical harmonic stacking for the singlets of Earth's normal modes of free oscillation

    NASA Astrophysics Data System (ADS)

    Chao, Benjamin F.; Ding, Hao

    2014-08-01

    We extend the spherical harmonic stacking (SHS) method of Buland et al. (1979) for the radial (vertical) component in the seismogram to the transverse (horizontal) components of the displacement field. Taking advantage of the orthogonality of the spherical harmonic functions (scalar and vectorial), SHS isolates and accentuates the signals of individual singlets of the Earth's normal modes of free oscillation. We apply the SHS on the broadband Incorporated Research Institutions for Seismology (IRIS) seismograms from up to 97 IRIS seismic stations for the 2004 Sumatra-Andaman earthquake, in experiments targeted to spheroidal as well as toroidal modes—2S1, 0S3, 2S2, 3S1, 1S3, 0T2, and 0T3. We report the complete resolution of the singlet frequencies of these multiplets, some for the first time, and estimate the singlets' complex frequencies using the frequency domain autoregressive method of Chao and Gilbert (1980). The latter contain useful information to be used in inversions for the 3-D structure of the Earth's interior.

  4. An Experiential Learning Activity Demonstrating Normal and Phobic Anxiety

    ERIC Educational Resources Information Center

    Canu, Will H.

    2008-01-01

    This article describes an activity for an undergraduate abnormal psychology course that used student-generated data to illustrate normal versus clinically significant anxiety responses related to specific phobias. Students (N = 37) viewed 14 images of low- or high-anxiety valence and rated their subjective response to each. Discussion in a…

  5. Normal modes of oscillation of the Asinelli and Garisenda towers in Bologna (Italy)

    NASA Astrophysics Data System (ADS)

    Morelli, A.; Azzara, R. M.; Cavaliere, A.; Zaccarelli, L.

    2013-12-01

    The Asinelli and Garisenda medieval towers represent the best-know city landmark in Bologna. Asinelli is also known to physics historians for early experiments on free fall of bodies for the first measurements of g (Giovanni Battista Riccioli, ca. 1650) and proof of Earth rotation (Giovanni Battista Guglielmini, 1791). The Two Towers (as they are commonly known) are essentially tall, square cross-section hollow masonry cuboids. Taller Asinelli, built between 1109 and 1119, is 97 m high, with an overhang of 2.2 m, while more seriously leaning Garisenda has an overhang of 3.2 m with a heigth of 48 m. During the summer of 2012 -- in the aftermath of two M≈6 earthquakes occurred in the proximity of the city -- the permanent engineering monitoring system of the towers has been temporarily supplemented by 6 seismometric stations installed at different levels inside the masonry buildings, to study their dynamical response to induced vibrations. We have thus been able to observe and measure the oscillation of the two towers excited by ambient noise, mostly due to city traffic. The two towers show similar behaviour, more clear in taller Asinelli. The first three flexural normal modes of oscillation, and the first torsional mode, can easily be detected. Their frequencies are split because of the asymmetry due to leaning of the tower. This asymmetry produces slightly different frequencies of oscillation in two orthogonal directions, quite consistent with preliminary dynamical modeling. Horizontal particle-motion polarization plots clearly show the cyclic energy transfer between these two degrees of freedom of the system. Oscillations of taller Asinelli influence its close sister, such that the Asinelli spectral signature can also be easily recognized in the motion recorded at the base of Garisenda, overimposed over Garisenda own free oscillations. Horizontal component polarization analysis done simultaneously at the two ground-level stations often point to a nearby common

  6. Different mode-locking methods in high energy all-normal dispersion Yb femtosecond all-fiber lasers

    NASA Astrophysics Data System (ADS)

    Szczepanek, Jan; Michalska, Maria; Kardaś, Tomasz; Radzewicz, Czesław; Stepanenko, Yuriy

    2015-05-01

    Ultrafast all-fiber oscillators are currently one of the most rapidly developing laser technologies. Many advantages like: environmental stability, low sensitivity to misalignment, excellent beam quality (intrinsic single transverse mode operation), high energy and an excellent active medium efficiency make them the lasers of choice for a variety of applications. In this paper the designs of all-fiber all-normal dispersion femtosecond lasers are described. Due to large positive chirp, the pulses inside the cavity are highly stretched in time and they can achieve higher energies with the same peak power as shorter pulses. High insensitivity to mechanical perturbations or temperature drift is another highly valued property of presented configurations. Two of reported lasers are extremely stable due to the fact that their cavities are built entirely of polarization maintaining fibers and optical elements. We used highly Yb3+ ions doped fibers as an active medium pumped by a fiber coupled 976 nm laser diode. The central wavelength of our laser oscillators was 1030 nm. Three methods of passive mode-locking in all-fiber cavities were studied. In particular, the designs with Nonlinear Polarization Evolution (NPE), Nonlinear Optical Loop Mirror (NOLM) and Nonlinear Amplifying Loop Mirror (NALM) as artificial saturable absorbers were investigated. The most attention was paid to all-PM-fiber configurations. We present two self-starting, high energy, all-fiber configurations: one delivering pulses with energy of 4.3 nJ and dechirped pulse duration of 150 fs based on the NALM and another with a 6.8 nJ, 390 fs pulses in configuration with the NOLM. The influence of different artificial saturable absorber on output pulse characteristics were studied and analyzed.

  7. Normal mode analysis of macromolecular systems with the mobile block Hessian method

    NASA Astrophysics Data System (ADS)

    Ghysels, An; Van Speybroeck, Veronique; Van Neck, Dimitri; Brooks, Bernard R.; Waroquier, Michel

    2015-01-01

    Until recently, normal mode analysis (NMA) was limited to small proteins, not only because the required energy minimization is a computationally exhausting task, but also because NMA requires the expensive diagonalization of a 3Na×3Na matrix with Na the number of atoms. A series of simplified models has been proposed, in particular the Rotation-Translation Blocks (RTB) method by Tama et al. for the simulation of proteins. It makes use of the concept that a peptide chain or protein can be seen as a subsequent set of rigid components, i.e. the peptide units. A peptide chain is thus divided into rigid blocks with six degrees of freedom each. Recently we developed the Mobile Block Hessian (MBH) method, which in a sense has similar features as the RTB method. The main difference is that MBH was developed to deal with partially optimized systems. The position/orientation of each block is optimized while the internal geometry is kept fixed at a plausible - but not necessarily optimized - geometry. This reduces the computational cost of the energy minimization. Applying the standard NMA on a partially optimized structure however results in spurious imaginary frequencies and unwanted coordinate dependence. The MBH avoids these unphysical effects by taking into account energy gradient corrections. Moreover the number of variables is reduced, which facilitates the diagonalization of the Hessian. In the original implementation of MBH, atoms could only be part of one rigid block. The MBH is now extended to the case where atoms can be part of two or more blocks. Two basic linkages can be realized: (1) blocks connected by one link atom, or (2) by two link atoms, where the latter is referred to as the hinge type connection. In this work we present the MBH concept and illustrate its performance with the crambin protein as an example.

  8. Normal modes of the atmosphere as estimated by principal oscillation patterns and derived from quasigeostrophic theory

    SciTech Connect

    Schnur, R.; Storch, H. von ); Schmitz, G.; Grieger, N. )

    1993-08-01

    The principal oscillation pattern (POP) analysis is a technique to empirically identify time-dependent spatial patterns in a multivariate time series of geophysical or other data. In order to investigate medium-scale and synoptic waves in the atmosphere it has been applied to tropospheric geopotential height fields of ECMWF analyses from 1984 to 1987. The data have been subjected to zonal Fourier decomposition and to time filtering so that variations with periods between 3 and 25 days were retained. Analyses have been performed separately for each zonal wavenumber 5-9 on the Northern Hemisphere in winter and on the Southern Hemisphere in summer (DJF). POPs can be seen as normal modes of a linear approximation to a more complex dynamical system. The system matrix is estimated from observations of nature. This concept is compared with conventional stability analysis where the system matrix of the linear system is derived from theoretical, in this case quasigeostrophic, reasoning. Only the mean basic flow depends on time- and space-averaged fields of observed wind and temperature from the ECMWF data. It turns out that the most significant POPs are very similar in time and spatial structure to the most unstable waves in the stability analysis. They describe the linear growth phase of baroclinic, unstable waves that propagate eastward with periods of 3-7 days. Since the POPs are purely derived from observations, the results indicate the appropriateness of the assumptions usually made in linear stability analysis of zonally symmetric flows to explain high-frequency atmospheric fluctuations. Moreover, the POP analysis reveals patterns that are not found in the linear stability analysis. These can possibly be attributed to the nonlinear decay phase of baroclinic waves. Eliassen-Palm cross sections help clarify the interpretation of the POPs in terms of the life cycle of nonlinear baroclinic waves. 24 refs., 14 figs.

  9. Normal mode analysis of macromolecular systems with the mobile block Hessian method

    SciTech Connect

    Ghysels, An; Van Speybroeck, Veronique; Van Neck, Dimitri; Waroquier, Michel; Brooks, Bernard R.

    2015-01-22

    Until recently, normal mode analysis (NMA) was limited to small proteins, not only because the required energy minimization is a computationally exhausting task, but also because NMA requires the expensive diagonalization of a 3N{sub a}×3N{sub a} matrix with N{sub a} the number of atoms. A series of simplified models has been proposed, in particular the Rotation-Translation Blocks (RTB) method by Tama et al. for the simulation of proteins. It makes use of the concept that a peptide chain or protein can be seen as a subsequent set of rigid components, i.e. the peptide units. A peptide chain is thus divided into rigid blocks with six degrees of freedom each. Recently we developed the Mobile Block Hessian (MBH) method, which in a sense has similar features as the RTB method. The main difference is that MBH was developed to deal with partially optimized systems. The position/orientation of each block is optimized while the internal geometry is kept fixed at a plausible - but not necessarily optimized - geometry. This reduces the computational cost of the energy minimization. Applying the standard NMA on a partially optimized structure however results in spurious imaginary frequencies and unwanted coordinate dependence. The MBH avoids these unphysical effects by taking into account energy gradient corrections. Moreover the number of variables is reduced, which facilitates the diagonalization of the Hessian. In the original implementation of MBH, atoms could only be part of one rigid block. The MBH is now extended to the case where atoms can be part of two or more blocks. Two basic linkages can be realized: (1) blocks connected by one link atom, or (2) by two link atoms, where the latter is referred to as the hinge type connection. In this work we present the MBH concept and illustrate its performance with the crambin protein as an example.

  10. Patterns of plasminogen activator production in cultured normal embryonic cells

    PubMed Central

    1977-01-01

    Cultured normal low-passage embryo fibroblasts, from a number of species, and two untransformed clones of a Balb/3T3 line elaborate increasing amounts of plasminogen activator (PA) as they approach confluence; the low-passage cells then lose this PA activity after reaching confluence, while the 3T3 cells retain it indefinitely. Even at their peaks, however, the PA activities of the low-passage cells remain well below those of the corresponding virally or spontaneously transformed cells. The PA increases in normal cells are probably a result of PA production rather than of adsorption of secreted PA to the cell surface, or of changes in cell-associated protease inhibitors. The elaboration of PA by normal cells is dependent upon their metabolic activity, such that the level of serum supplementation and the growth phase of the culture directly influence the level of cell-associated PA observed. In addition, there may be a component of serum which exerts a negative control on PA production and which is not an acid-labile protease inhibitor. PMID:21193

  11. Transverse, normal modes of vibration of a cantilever Timoshenko beam with a mass elastically mounted at the free end

    NASA Astrophysics Data System (ADS)

    Rossit, C. A.; Laura, P. A. A.

    2001-12-01

    An exact solution for the title problem is obtained by means of the classical eigenfunction approach. The natural frequencies are computed for a wide range of the intervening mechanical and geometric parameters. Normal modes of transverse vibration are plotted for some cases of practical interest. The problem is technically important in several areas of applied science and technology.

  12. On the mode-coupling treatment of collective density fluctuations for quantum liquids: para-hydrogen and normal liquid helium.

    PubMed

    Kletenik-Edelman, Orly; Reichman, David R; Rabani, Eran

    2011-01-28

    A novel quantum mode coupling theory combined with a kinetic approach is developed for the description of collective density fluctuations in quantum liquids characterized by Boltzmann statistics. Three mode-coupling approximations are presented and applied to study the dynamic response of para-hydrogen near the triple point and normal liquid helium above the λ-transition. The theory is compared with experimental results and to the exact imaginary time data generated by path integral Monte Carlo simulations. While for liquid para-hydrogen the combination of kinetic and quantum mode-coupling theory provides semi-quantitative results for both short and long time dynamics, it fails for normal liquid helium. A discussion of this failure based on the ideal gas limit is presented. PMID:21280769

  13. On the mode-coupling treatment of collective density fluctuations for quantum liquids: para-hydrogen and normal liquid helium.

    PubMed

    Kletenik-Edelman, Orly; Reichman, David R; Rabani, Eran

    2011-01-28

    A novel quantum mode coupling theory combined with a kinetic approach is developed for the description of collective density fluctuations in quantum liquids characterized by Boltzmann statistics. Three mode-coupling approximations are presented and applied to study the dynamic response of para-hydrogen near the triple point and normal liquid helium above the λ-transition. The theory is compared with experimental results and to the exact imaginary time data generated by path integral Monte Carlo simulations. While for liquid para-hydrogen the combination of kinetic and quantum mode-coupling theory provides semi-quantitative results for both short and long time dynamics, it fails for normal liquid helium. A discussion of this failure based on the ideal gas limit is presented.

  14. The quasi-normal modes of charged scalar fields in Kerr-Newman black hole and its geometric interpretation

    NASA Astrophysics Data System (ADS)

    Zhao, Peng; Tian, Yu; Wu, Xiaoning; Sun, Zhao-Yong

    2015-11-01

    It is well-known that there is a geometric correspondence between high-frequency quasi-normal modes (QNMs) and null geodesics (spherical photon orbits). In this paper, we generalize such correspondence to charged scalar field in Kerr-Newman space-time. In our case, the particle and black hole are all charged, so one should consider non-geodesic orbits. Using the WKB approximation, we find that the real part of quasi-normal frequency corresponds to the orbits frequency, the imaginary part of the frequency corresponds to the Lyapunov exponent of these orbits and the eigenvalue of angular equation corresponds to carter constant. From the properties of the imaginary part of quasi-normal frequency of charged massless scalar field, we can still find that the QNMs of charged massless scalar field possess the zero damping modes in extreme Kerr-Newman spacetime under certain condition which has been fixed in this paper.

  15. Synthesis, vibrational spectra, and normal mode analysis of nickel(II) 1,5-dihydroxy-1,5-dimethyloctaethylbacteriochlorin. A model for bacteriochlorophylls

    SciTech Connect

    Hu, S.; Mukherjee, A.; Spiro, T.G. )

    1993-12-29

    Resonance Raman (RR) and FT-IR spectra are reported for nickel(II) 1,5-dihydroxy-1,5-dimethyloctaethylbacteriochlorin [Ni(HOEBC)] and its meso-d[sub 4] isotopomer. All the in-plane skeletal RR-active modes and most IR-active modes are assigned with the aid of a normal mode analysis by using a force field developed for nickel(II) octaethylporphyrin and by scaling the bond stretch force constants to bond lengths revealed in the crystal structure of nickel(II) octaethylbacteriochlorin. The calculated eigenvectors provide insight into the essential vibrational characteristics of metallobacteriochlorins. The RR spectra of Ni(HOEBC) were acquired with a variety of excitation wavelengths, near resonance with the B[sub x], Q[sub x], and Q[sub y] transitions. The enhancement pattern of the observed RR intensities reveals that the B[sub x]- and near-Q[sub y]-resonant spectra are dominated by Franck-Condon-active modes while the Q[sub x]-resonant spectrum is dominated by vibronically active modes. The B[sub x]-resonant spectrum also shows significant vibronic scattering, via coupling between the B[sub x]- and B[sub y]-excited states. Frequencies correlate well among Ni(II) complexes of octaethylporphine (OEP) and hydroporphyrins for modes containing similar local mode contributions, when allowance is made for C[sub beta]-C[sub beta] bond order reduction and the effects of symmetry lowering. Assignments are proposed for the existing RR data on bacteriochlorophyll a. 32 refs., 14 figs., 6 tabs.

  16. The influence of phase-locking on internal resonance from a nonlinear normal mode perspective

    NASA Astrophysics Data System (ADS)

    Hill, T. L.; Neild, S. A.; Cammarano, A.; Wagg, D. J.

    2016-09-01

    When a nonlinear system is expressed in terms of the modes of the equivalent linear system, the nonlinearity often leads to modal coupling terms between the linear modes. In this paper it is shown that, for a system to exhibit an internal resonance between modes, a particular type of nonlinear coupling term is required. Such terms impose a phase condition between linear modes, and hence are denoted phase-locking terms. The effect of additional modes that are not coupled via phase-locking terms is then investigated by considering the backbone curves of the system. Using the example of a two-mode model of a taut horizontal cable, the backbone curves are derived for both the case where phase-locked coupling terms exist, and where there are no phase-locked coupling terms. Following this, an analytical method for determining stability is used to show that phase-locking terms are required for internal resonance to occur. Finally, the effect of non-phase-locked modes is investigated and it is shown that they lead to a stiffening of the system. Using the cable example, a physical interpretation of this is provided.

  17. Brain cholinesterase activity of apparently normal wild birds

    USGS Publications Warehouse

    Hill, E.F.

    1988-01-01

    Organophosphorus and carbamate pesticides are potent anticholinesterase substances that have killed large numbers of wild birds of various species. Cause of death is diagnosed by demonstration of depressed brain cholinesterase (ChE) activity in combination with chemical detection of anticholinesterase residue in the affected specimen. ChE depression is determined by comparison of the affected specimen to normal ChE activity for a sample of control specimens of the same species, but timely procurement of controls is not always possible. Therefore, a reference file of normal whole brain ChE activity is provided for 48 species of wild birds from North America representing 11 orders and 23 families for use as emergency substitutes in diagnosis of anticholinesterase poisoning. The ChE values, based on 83 sets of wild control specimens from across the United States, are reproducible provided the described procedures are duplicated. Overall, whole brain ChE activity varied nearly three-fold among the 48 species represented, but it was usually similar for closely related species. However, some species were statistically separable in most families and some species of the same genus differed as much as 50%.

  18. Black-hole normal modes: A WKB approach. III. The Reissner-Nordström black hole

    NASA Astrophysics Data System (ADS)

    Kokkotas, Kostas D.; Schutz, Bernard F.

    1988-06-01

    Complex frequencies of the normal modes of the Reissner-Nordström black hole are computed by two independent methods. The first is a high-order WKB approach devised by Schutz and Will and extended by Iyer and Will for the Schwarzschild case. The second is direct numerical integration using a method developed by Chandrasekhar and Detweiler, thereby extending earlier results of Gunter. The WKB results agree with the numerical ones with an error less than 1% for the lowest-order modes. For somewhat higher orders, the numerical techniques fail but the WKB method continues to give eigenfrequencies that should be reasonably accurate.

  19. Joint inversion of normal-mode and finite-frequency S-wave data using an irregular tomographic grid

    NASA Astrophysics Data System (ADS)

    Zaroli, Christophe; Lambotte, Sophie; Lévêque, Jean-Jacques

    2015-12-01

    Global-scale tomographic models should aim at satisfying the full seismic spectrum. For this purpose, and to better constrain isotropic 3-D variations of shear velocities in the mantle, we tackle a joint inversion of spheroidal normal-mode structure coefficients and multiple-frequency S-wave delay times. In all previous studies for which normal modes were jointly inverted for, with body and/or surface waves, the mantle was laterally parametrized with uniform basis functions, such as spherical harmonics, equal-area blocks and evenly spaced spherical splines. In particular, spherical harmonics naturally appear when considering the Earth's free oscillations. However, progress towards higher resolution joint tomography requires a movement away from such uniform parametrization to overcome its computational inefficiency to adapt to local variations in resolution. The main goal of this study is to include normal modes into a joint inversion based upon a non-uniform parametrization that is adapted to the spatially varying smallest resolving length of the data. Thus, we perform the first joint inversion of normal-mode and body-wave data using an irregular tomographic grid, optimized according to ray density. We show how to compute the projection of 3-D sensitivity kernels for both data sets onto our parametrization made up of spherical layers spanned with irregular Delaunay triangulations. This approach, computationally efficient, allows us to map into the joint model multiscale structural informations from data including periods in the 10-51 s range for body waves and 332-2134 s for normal modes. Tomographic results are focused on the 400-2110 km depth range, where our data coverage is the most relevant. We discuss the potential of a better resolution where the grid is fine, compared to spherical harmonics up to degree 40, as the number of model parameters is similar. Our joint model seems to contain coherent structural components beyond degree 40, such as those related

  20. Stable, accurate and efficient computation of normal modes for horizontal stratified models

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Chen, Xiaofei

    2016-06-01

    We propose an adaptive root-determining strategy that is very useful when dealing with trapped modes or Stoneley modes whose energies become very insignificant on the free surface in the presence of low-velocity layers or fluid layers in the model. Loss of modes in these cases or inaccuracy in the calculation of these modes may then be easily avoided. Built upon the generalized reflection/transmission coefficients, the concept of "family of secular functions" that we herein call "adaptive mode observers", is thus naturally introduced to implement this strategy, the underlying idea of which has been distinctly noted for the first time and may be generalized to other applications such as free oscillations or applied to other methods in use when these cases are encountered. Additionally, we have made further improvements upon the generalized reflection/transmission coefficient method; mode observers associated with only the free surface and low-velocity layers (and the fluid/solid interface if the model contains fluid layers) are adequate to guarantee no loss and high precision at the same time of any physically existent modes without excessive calculations. Finally, the conventional definition of the fundamental mode is reconsidered, which is entailed in the cases under study. Some computational aspects are remarked on. With the additional help afforded by our superior root-searching scheme and the possibility of speeding calculation using a less number of layers aided by the concept of "turning point", our algorithm is remarkably efficient as well as stable and accurate and can be used as a powerful tool for widely related applications.

  1. Stable, accurate and efficient computation of normal modes for horizontal stratified models

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Chen, Xiaofei

    2016-08-01

    We propose an adaptive root-determining strategy that is very useful when dealing with trapped modes or Stoneley modes whose energies become very insignificant on the free surface in the presence of low-velocity layers or fluid layers in the model. Loss of modes in these cases or inaccuracy in the calculation of these modes may then be easily avoided. Built upon the generalized reflection/transmission coefficients, the concept of `family of secular functions' that we herein call `adaptive mode observers' is thus naturally introduced to implement this strategy, the underlying idea of which has been distinctly noted for the first time and may be generalized to other applications such as free oscillations or applied to other methods in use when these cases are encountered. Additionally, we have made further improvements upon the generalized reflection/transmission coefficient method; mode observers associated with only the free surface and low-velocity layers (and the fluid/solid interface if the model contains fluid layers) are adequate to guarantee no loss and high precision at the same time of any physically existent modes without excessive calculations. Finally, the conventional definition of the fundamental mode is reconsidered, which is entailed in the cases under study. Some computational aspects are remarked on. With the additional help afforded by our superior root-searching scheme and the possibility of speeding calculation using a less number of layers aided by the concept of `turning point', our algorithm is remarkably efficient as well as stable and accurate and can be used as a powerful tool for widely related applications.

  2. Dynamic activity dependence of in vivo normal knee kinematics.

    PubMed

    Moro-oka, Taka-aki; Hamai, Satoshi; Miura, Hiromasa; Shimoto, Takeshi; Higaki, Hidehiko; Fregly, Benjamin J; Iwamoto, Yukihide; Banks, Scott A

    2008-04-01

    Dynamic knee kinematics were analyzed for normal knees in three activities, including two different types of maximum knee flexion. Continuous X-ray images of kneel, squat, and stair climb motions were taken using a large flat panel detector. CT-derived bone models were used for model registration-based 3D kinematic measurement. Three-dimensional joint kinematics and contact locations were determined using three methods: bone-fixed coordinate systems, interrogation of CT-based bone model surfaces, and interrogation of MR-based articular cartilage model surfaces. The femur exhibited gradual external rotation throughout the flexion range. Tibiofemoral contact exhibited external rotation, with contact locations translating posterior while maintaining 15 degrees to 20 degrees external rotation from 20 degrees to 80 degrees of flexion. From 80 degrees to maximum flexion, contact locations showed a medial pivot pattern. Kinematics based on bone-fixed coordinate systems differed from kinematics based on interrogation of CT and MR surfaces. Knee kinematics varied significantly by activity, especially in deep flexion. No posterior subluxation occurred for either femoral condyle in maximum knee flexion. Normal knees accommodate a range of motions during various activities while maintaining geometric joint congruency.

  3. Conformally covariant coupled non-linear field theory on the hypercone: Vacuum solutions and quantization of normal modes

    SciTech Connect

    Aciktepe, T.; Akdeniz, K.G.; Barut, A.O.; Kalayci, J.

    1988-01-01

    For the conformally covariant coupled non-linear spinor-scalar field of the sigma-model type the authors show that the non-trivial vacuum instanton solutions have a geometric meaning as constant spinors on the five-dimensional hypercone. The quantized fields around these solutions correspond to the normal modes of the hypercone. A connection is thus established between field theory, particle spectrum of the fields and quantized excitations of a geometry (the hypercone).

  4. Multi-normal mode-splitting for an optical cavity with electromagnetically induced transparency medium.

    PubMed

    Yu, Xudong; Zhang, Jing

    2010-03-01

    We theoretically study the cavity transmission spectra with three-level atoms coupled by a coherent external control field in the superstrong coupling regime (atoms-cavity coupling strength g [square root] N is near or larger than the cavity free-spectral range DeltaFSR). When satisfying the superstrong coupling condition by increasing the number of the interaction atoms, more than one FSR cavity modes interact with atoms and each mode will split three peaks, which can be well explained by the linear dispersion enhancement of electromagnetically induced transparency medium due to the largely increased atomic density in the cavity.

  5. Calculation, normalization, and perturbation of quasinormal modes in coupled cavity-waveguide systems.

    PubMed

    Kristensen, Philip Trøst; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2014-11-15

    We show how one can use a nonlocal boundary condition, which is compatible with standard frequency domain methods, for numerical calculation of quasinormal modes in optical cavities coupled to waveguides. In addition, we extend the definition of the quasinormal mode norm by use of the theory of divergent series to provide a framework for modeling of optical phenomena in such coupled cavity-waveguide systems. As example applications, we calculate the Purcell factor and study perturbative changes in the complex resonance frequency of a photonic crystal cavity coupled to a defect waveguide.

  6. Calculation of the Rotational Normal Modes of Oceans and Lakes with General Orthogonal Coordinates

    NASA Astrophysics Data System (ADS)

    Bennett, John R.; Schwab, David J.

    1981-12-01

    A finite-difference method for computing the frequency and structure of the rotational modes of oscillation of enclosed seas is tested against known solutions for: (1) a circular basin with a parabolic depth law, (2) a circular, flat basin with a linear variation of the Coriolis parameter, and (3) an elliptic paraboloid. Several higher modes of the elliptic paraboloid are also calculated. The method uses the non-divergent assumption and solves the barotropic vorticity equation in general orthogonal coordinates generated by a conformal map of the shoreline onto the unit circle. The numerical procedure for calculating the conformal map of an arbitrarily shaped basin is presented.

  7. Calculation, normalization, and perturbation of quasinormal modes in coupled cavity-waveguide systems.

    PubMed

    Kristensen, Philip Trøst; de Lasson, Jakob Rosenkrantz; Gregersen, Niels

    2014-11-15

    We show how one can use a nonlocal boundary condition, which is compatible with standard frequency domain methods, for numerical calculation of quasinormal modes in optical cavities coupled to waveguides. In addition, we extend the definition of the quasinormal mode norm by use of the theory of divergent series to provide a framework for modeling of optical phenomena in such coupled cavity-waveguide systems. As example applications, we calculate the Purcell factor and study perturbative changes in the complex resonance frequency of a photonic crystal cavity coupled to a defect waveguide. PMID:25490468

  8. A Pictorial Visualization of Normal Mode Vibrations of the Fullerene (C[subscript 60]) Molecule in Terms of Vibrations of a Hollow Sphere

    ERIC Educational Resources Information Center

    Dunn, Janette L.

    2010-01-01

    Understanding the normal mode vibrations of a molecule is important in the analysis of vibrational spectra. However, the complicated 3D motion of large molecules can be difficult to interpret. We show how images of normal modes of the fullerene molecule C[subscript 60] can be made easier to understand by superimposing them on images of the normal…

  9. Low-frequency normal modes that describe allosteric transitions in biological nanomachines are robust to sequence variations.

    PubMed

    Zheng, Wenjun; Brooks, Bernard R; Thirumalai, D

    2006-05-16

    By representing the high-resolution crystal structures of a number of enzymes using the elastic network model, it has been shown that only a few low-frequency normal modes are needed to describe the large-scale domain movements that are triggered by ligand binding. Here we explore a link between the nearly invariant nature of the modes that describe functional dynamics at the mesoscopic level and the large evolutionary sequence variations at the residue level. By using a structural perturbation method (SPM), which probes the residue-specific response to perturbations (or mutations), we identify a sparse network of strongly conserved residues that transmit allosteric signals in three structurally unrelated biological nanomachines, namely, DNA polymerase, myosin motor, and the Escherichia coli chaperonin. Based on the response of every mode to perturbations, which are generated by interchanging specific sequence pairs in a multiple sequence alignment, we show that the functionally relevant low-frequency modes are most robust to sequence variations. Our work shows that robustness of dynamical modes at the mesoscopic level is encoded in the structure through a sparse network of residues that transmit allosteric signals.

  10. Active mode-locked lasers and other photonic devices using electro-optic whispering gallery mode resonators

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey B. (Inventor); Ilchenko, Vladimir (Inventor); Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor)

    2006-01-01

    Techniques and devices using whispering gallery mode (WGM) optical resonators, where the optical materials of the WGM resonators exhibit an electro-optical effect to perform optical modulation. Examples of actively mode-locked lasers and other devices are described.

  11. Characterization of mode-locking in an all-fiber, all normal dispersion ytterbium based fiber oscillator

    NASA Astrophysics Data System (ADS)

    Cserteg, András.; Sági, Veronika; Drozdy, András.; Varallyay, Zoltán.; Gajdátsy, Gábor

    2015-03-01

    An ytterbium based all fiber, all normal dispersion fiber oscillator with integrated SESAM can have several operation modes like mode-locked, Q-switched and noise-like. To know and to control the quality of the mode-locking is essential for the application of such laser oscillators, otherwise the whole laser setup can be damaged or the expected operation characteristics of the oscillator driven systems cannot be achieved. Usually the two-photon signal generated by the short pulses is used to indicate the mode locked operation, however such detection can be misleading in certain cases and not always able to predict the forthcoming degradation or vanishing of mode locking. The characterization method that we propose uses only the radio frequency spectrum of the oscillator output and can identify the different operation regimes of our laser setup. The optical spectra measured simultaneously with the RF signals proves the reliability of our method. With this kind of characterization stable mode locking can be initiated and maintained during the laser operation. The method combined with the ability to align the polarization states automatically in the laser cavity leads to the possibility to record a polarization map where the stability domains can be identified and classified. With such map the region where the mode locking is self starting and maintainable with minimal polarization alignment can be selected. The developed oscillator reported here with its compact setup and self alignment ability can be a reliable source with long term error free operation without the need of expensive monitoring tools.

  12. A coarse-grained normal mode approach for macromolecules: an efficient implementation and application to Ca(2+)-ATPase.

    PubMed Central

    Li, Guohui; Cui, Qiang

    2002-01-01

    A block normal mode (BNM) algorithm, originally proposed by Tama et al., (Proteins Struct. Func. Genet. 41:1-7, 2000) was implemented into the simulation program CHARMM. The BNM approach projects the hessian matrix into local translation/rotation basis vectors and, therefore, dramatically reduces the size of the matrix involved in diagonalization. In the current work, by constructing the atomic hessian elements required in the projection operation on the fly, the memory requirement for the BNM approach has been significantly reduced from that of standard normal mode analysis and previous implementation of BNM. As a result, low frequency modes, which are of interest in large-scale conformational changes of large proteins or protein-nucleic acid complexes, can be readily obtained. Comparison of the BNM results with standard normal mode analysis for a number of small proteins and nucleic acids indicates that many properties dominated by low frequency motions are well reproduced by BNM; these include atomic fluctuations, the displacement covariance matrix, vibrational entropies, and involvement coefficients for conformational transitions. Preliminary application to a fairly large system, Ca(2+)-ATPase (994 residues), is described as an example. The structural flexibility of the cytoplasmic domains (especially domain N), correlated motions among residues on domain interfaces and displacement patterns for the transmembrane helices observed in the BNM results are discussed in relation to the function of Ca(2+)-ATPase. The current implementation of the BNM approach has paved the way for developing efficient sampling algorithms with molecular dynamics or Monte Carlo for studying long-time scale dynamics of macromolecules. PMID:12414680

  13. A Simple Reduction Process for the Normal Vibrational Modes Occurring in Linear Molecules

    ERIC Educational Resources Information Center

    McInerny, William

    2005-01-01

    The students in molecular spectroscopy courses are often required to determine the permitted normal vibrations for linear molecules that belong to particular groups. The reducible group representations generated by the use of Cartesian coordinates can be reduced by the use of a simple algebraic process applied to the group representations. The…

  14. Normal-mode spectrum of finite-sized granular systems: The effects of fluid viscosity at the grain contacts.

    PubMed

    Valenza, John; Johnson, David Linton

    2012-04-01

    We investigate the effects of adsorbed films on the attenuative properties of loose granular media occupying a finite-sized rigid container that is open at the top. We measure the effective mass, M[over ̃](ω), of loose tungsten particles prepared under two different sets of conditions: (i) We lightly coat tungsten grains with a fixed volume fraction of silicone oil (polydimethylsiloxane, PDMS), where the liquid viscosity is varied for individual realizations, and (ii) in the other set of experiments we vary the humidity. On a theoretical level, we are able to decompose the effective mass into a sum over the contributions from each of the normal modes of the granular medium. Our results indicate that increasing either the PDMS viscosity or the humidity, as the case may be, markedly increases the damping rate of each normal mode relevant to our measurements. However, there is appreciable damping even in the absence of any macroscopic film. With a notable exception in the case of the highest humidity in the humidity-controlled experiments, all the relevant modes are weakly damped in the sense of a microscopic theory based on damped contact forces between rigid particles.

  15. Normal-mode spectrum of finite-sized granular systems: The effects of fluid viscosity at the grain contacts

    NASA Astrophysics Data System (ADS)

    Valenza, John; Johnson, David Linton

    2012-04-01

    We investigate the effects of adsorbed films on the attenuative properties of loose granular media occupying a finite-sized rigid container that is open at the top. We measure the effective mass, M˜(ω), of loose tungsten particles prepared under two different sets of conditions: (i) We lightly coat tungsten grains with a fixed volume fraction of silicone oil (polydimethylsiloxane, PDMS), where the liquid viscosity is varied for individual realizations, and (ii) in the other set of experiments we vary the humidity. On a theoretical level, we are able to decompose the effective mass into a sum over the contributions from each of the normal modes of the granular medium. Our results indicate that increasing either the PDMS viscosity or the humidity, as the case may be, markedly increases the damping rate of each normal mode relevant to our measurements. However, there is appreciable damping even in the absence of any macroscopic film. With a notable exception in the case of the highest humidity in the humidity-controlled experiments, all the relevant modes are weakly damped in the sense of a microscopic theory based on damped contact forces between rigid particles.

  16. Transient analysis of nonlinear Euler-Bernoulli micro-beam with thermoelastic damping, via nonlinear normal modes

    NASA Astrophysics Data System (ADS)

    Haddadzadeh Hendou, Ramtin; Karami Mohammadi, Ardeshir

    2014-11-01

    In this paper an Euler-Bernoulli model has been used for vibration analysis of micro-beams with large transverse deflection. Thermoelastic damping is considered to be the dominant damping mechanism and introduced as imaginary stiffness into the equation of motion by evaluating temperature profile as a function of lateral displacement. The obtained equation of motion is analyzed in the case of pure single mode motion by two methods; nonlinear normal mode theory and the Galerkin procedure. In contrast with the Galerkin procedure, nonlinear normal mode analysis introduces a nonconventional nonlinear damping term in modal oscillator which results in strong damping in case of large amplitude vibrations. Evaluated modal oscillators are solved using harmonic balance method and tackling damping terms introduced as an imaginary stiffness is discussed. It has been shown also that nonlinear modal analysis of micro-beam with thermoelastic damping predicts parameters such as inverse quality factor, and frequency shift, to have an extrema point at certain amplitude during transient response due to the mentioned nonlinear damping term; and the effect of system's characteristics on this critical amplitude has also been discussed.

  17. Normal-mode spectrum of finite-sized granular systems: The effects of fluid viscosity at the grain contacts.

    PubMed

    Valenza, John; Johnson, David Linton

    2012-04-01

    We investigate the effects of adsorbed films on the attenuative properties of loose granular media occupying a finite-sized rigid container that is open at the top. We measure the effective mass, M[over ̃](ω), of loose tungsten particles prepared under two different sets of conditions: (i) We lightly coat tungsten grains with a fixed volume fraction of silicone oil (polydimethylsiloxane, PDMS), where the liquid viscosity is varied for individual realizations, and (ii) in the other set of experiments we vary the humidity. On a theoretical level, we are able to decompose the effective mass into a sum over the contributions from each of the normal modes of the granular medium. Our results indicate that increasing either the PDMS viscosity or the humidity, as the case may be, markedly increases the damping rate of each normal mode relevant to our measurements. However, there is appreciable damping even in the absence of any macroscopic film. With a notable exception in the case of the highest humidity in the humidity-controlled experiments, all the relevant modes are weakly damped in the sense of a microscopic theory based on damped contact forces between rigid particles. PMID:22680464

  18. Engaging in activities involving information technology: dimensions, modes, and flow.

    PubMed

    Montgomery, Henry; Sharafi, Parvaneh; Hedman, Leif R

    2004-01-01

    An engagement mode involves a subject (e.g., a user of information technology, or IT) who is engaged in an activity with an object in a certain manner (the mode). The purpose of this study is to develop a general model of engagement modes that may be used for understanding how IT-related activities are shaped by properties of the user and the IT object. A questionnaire involving items on IT engagement and the experience of flow was administered to 300 participants. The results supported an engagement mode (EM) model involving 5 different engagement modes (enjoying/acceptance, ambition/curiosity, avoidance/hesitation, frustration/ anxiety, and efficiency/productivity) characterized on 3 dimensions (evaluation of object, locus of control between subject and object, and intrinsic or extrinsic focus of motivation). The flow experience follows from a balance between enjoying/ acceptance and efficiency/productivity propelled by ambition/curiosity. The EM model could provide a platform for considering how IT users, IT applications, and IT environments should work together to yield both enjoyment and efficiency. Actual or potential applications of this research include designing IT training programs on different levels of specificity. PMID:15359681

  19. Resistive wall mode active control physics design for KSTAR

    NASA Astrophysics Data System (ADS)

    Park, Y. S.; Sabbagh, S. A.; Bak, J. G.; Bialek, J. M.; Berkery, J. W.; Lee, S. G.; Oh, Y. K.

    2014-01-01

    As KSTAR H-mode operation approaches the region where the resistive wall mode (RWM) can be unstable, an important issue for future long pulse, high beta plasma operation is to evaluate RWM active feedback control performance using a planned active/passive RWM stabilization system on the device. In particular, an optimal design of feedback sensors allows mode stabilization up to the highest achievable βN close to the ideal with-wall limit, βNwall, with reduced control power requirements. The computed ideal n = 1 mode structure from the DCON code has been input to the VALEN-3D code to calculate the projected performance of an active RWM control system in the KSTAR three-dimensional conducting structure device geometry. Control performance with the midplane locked mode detection sensors, off-midplane saddle loops, and magnetic pickup coils is examined. The midplane sensors measuring the radial component of the mode perturbation is found to be strongly affected by the wall eddy current. The off-axis saddle loops with proper compensation of the prompt applied field are computed to provide stabilization at βN up to 86% of βNwall but the low RWM amplitude computed in the off-axis regions near the sensors can produce a low signal-to-noise ratio. The required control power and bandwidth are also estimated with varied noise levels in the feedback sensors. Further improvements have been explored by examining a new RWM sensor design motivated by the off-midplane poloidal magnetic field sensors in NSTX. The new sensors mounted off of the copper passive stabilizer plates near the device midplane show a clear advantage in control performance corresponding to achieving 99% of βNwall without the need of compensation of the prompt field. The result shows a significant improvement of RWM feedback stabilization using the new sensor set which motivates a future feedback sensor upgrade.

  20. Design of broadband linear micromachined ultrasonic transducer arrays by means of boundary element method coupled with normal mode theory.

    PubMed

    Boulmé, Audren; Certon, Dominique

    2015-09-01

    In view of the maturity of fabrication processes for capacitive micromachined ultrasonic transducers (cMUTs), engineers and researchers now need efficient and accurate modeling tools to design linear arrays according to a set of technological specifications, such as sensitivity, bandwidth, and directivity pattern. A simplified modeling tool was developed to meet this requirement. It consists of modeling one element as a set of cMUT columns, each being a 1-D periodic array of cMUTs. Model description and assessment of simulation results are given in the first part of the paper. The approach is based on the theory of linear systems so the output data are linked to input data through a large matrix, known as an admittance matrix. In the second part of the paper, we propose reorganization of matrix equations by applying the normal mode theory. From the modal decomposition, two categories of eigenmodes are highlighted, one for which all cMUTs vibrate in phase (the fundamental mode) and the others, which correspond to localized subwavelength resonances, known as baffle modes. The last part of the paper focuses mainly on the fundamental mode and gives several design strategies to optimize the frequency response of an element.

  1. An analysis of nearfield normal mode amplitude anomalies of the Landers earthquake

    NASA Technical Reports Server (NTRS)

    Watada, Shingo; Kanamori, Hiroo; Anderson, Don L.

    1993-01-01

    The 1992 Landers earthquake (M(sub w) = 7.3) occurred in the middle of the TERRAscope network. Long-period Rayleigh waves recorded at the TERRAscope stations (delta less than or = 3 deg) after traveling around the Earth show large amplitude anomalies, one order of magnitude larger than spherical Earth predictions up to a period of about 600 s. The ground motions over the epicentral region at and after the arrival of R4-5 are in phase at all stations. These observations are inconsistent with the nearly vertical strike slip mechanism of the Landers earthquake. Synthetic seismograms for a rotating, elliptic, and laterally heterogeneous Earth model calculated by the variational method agree well with the observed waveforms. Calculations for various 3D Earth models demonstrate that the amplitudes are very sensitive to the large scale aspherical structure in the crust and the mantle. The anomalies for modes shorter than 300 s period can be explained by lateral heterogeneity shallower than the upper mantle. Rotation of the Earth and lower mantle heterogeneity are required to explain mode amplitudes at longer periods. Current whole mantle seismic tomographic models can fully explain the observed amplitudes longer than 300 s. To assess the effect of the high order lateral heterogeneity in the mantle more precise estimate of the crustal correction is required.

  2. A comparison of the bounded derivative and the normal mode initialization methods using real data. [in numerical weather forecasting

    NASA Technical Reports Server (NTRS)

    Semazzi, F. H. M.; Navon, I. M.

    1985-01-01

    A bounded derivative initialization method (BDI) formerly used only in theoretical studies to balance gravitational wave influences is extended to a real world data set and the results are compared with those from a normal mode initialization (NMI). BDI proceeds by defining the characteristic scales of motion of interest and then constraining the time derivatives to match motions on a slow scale. A global barotropic model which considers orographic forcing is initialized by the scaled balance equations of the BDI scheme, which uses vorticity alone to achieve an initial balanced state. An external mode projector is employed to realize the NMI scheme, and five Machenhauer iterations reduce the total balance by four orders of magnitude. The initial states generated with both schemes are essentially equivalent, including the time evolution of a height field and divergence behavior being centered around regions of high orographic elevation.

  3. Significance of a two-domain structure in subunits of phycobiliproteins revealed by the normal mode analysis.

    PubMed

    Kikuchi, H; Wako, H; Yura, K; Go, M; Mimuro, M

    2000-09-01

    Phycobiliproteins are basic building blocks of phycobilisomes, a supra-molecular assembly for the light-capturing function of photosynthesis in cyanobacteria and red algae. One functional form of phycobiliproteins is a trimeric form consisting of three identical units having C(3) symmetry, with each unit composed of two kinds of subunits, the alpha-subunit and beta-subunit. These subunits have similar chain folds and can be divided into either globin-like or X-Y helices domains. We studied the significance of this two-domain structure for their assembled structures and biological function (light-absorption) using a normal mode analysis to investigate dynamic aspects of their three-dimensional structures. We used C-phycocyanin (C-PC) as an example, and focused on the interactions between the two domains. The normal mode analysis was carried out for the following two cases: 1) the whole subunit, including the two domains; and 2) the globin-like domain alone. By comparing the dynamic properties, such as correlative movements between residues and the fluctuations of individual residues, we found that the X-Y helices domain plays an important role not only in the C(3) symmetry assemblies of the subunits in phycobiliproteins, but also in stabilizing the light absorption property by suppressing the fluctuation of the specific Asp residues near the chromophore. Interestingly, the conformation of the X-Y helices domain corresponds to that of a module in pyruvate phosphate dikinase (PPDK). The module in PPDK is involved in the interactions of two domains, just as the X-Y helices domain is involved in the interactions of two subunits. Finally, we discuss the mechanical construction of the C-PC subunits based on the normal mode analysis.

  4. Mode-locked femtosecond all-normal all-PM Yb-doped fiber laser at 1060 nm

    NASA Astrophysics Data System (ADS)

    Bowen, Patrick; Singh, Harman; Runge, Antoine; Provo, Richard; Broderick, Neil G. R.

    2016-04-01

    We report an all-normal-dispersion, all-fibre, all-PM, laser operating at a central wavelength of 1060 nm. The laser is mode-locked using a nonlinear amplifying loop mirror and generates linearly polarised pulses that can be compressed to 360 fs. The laser is based on our earlier scheme operating at 1030 nm [1] and we discuss the similarities and differences between the two configurations. We also present amplification up to an output power of 1 W using a commercially built amplifier and show through numerical methods that this pulse may be recompressible to 1.65 ps.

  5. Meditation leads to reduced default mode network activity beyond an active task

    PubMed Central

    Garrison, Kathleen A.; Zeffiro, Thomas A.; Scheinost, Dustin; Constable, R. Todd; Brewer, Judson A.

    2015-01-01

    Meditation has been associated with relatively reduced activity in the default mode network, a brain network implicated in self-related thinking and mind wandering. However, previous imaging studies have typically compared meditation to rest despite other studies reporting differences in brain activation patterns between meditators and controls at rest. Moreover, rest is associated with a range of brain activation patterns across individuals that has only recently begun to be better characterized. Therefore, this study compared meditation to another active cognitive task, both to replicate findings that meditation is associated with relatively reduced default mode network activity, and to extend these findings by testing whether default mode activity was reduced during meditation beyond the typical reductions observed during effortful tasks. In addition, prior studies have used small groups, whereas the current study tested these hypotheses in a larger group. Results indicate that meditation is associated with reduced activations in the default mode network relative to an active task in meditators compared to controls. Regions of the default mode showing a group by task interaction include the posterior cingulate/precuneus and anterior cingulate cortex. These findings replicate and extend prior work indicating that suppression of default mode processing may represent a central neural process in long-term meditation, and suggest that meditation leads to relatively reduced default mode processing beyond that observed during another active cognitive task. PMID:25904238

  6. Meditation leads to reduced default mode network activity beyond an active task.

    PubMed

    Garrison, Kathleen A; Zeffiro, Thomas A; Scheinost, Dustin; Constable, R Todd; Brewer, Judson A

    2015-09-01

    Meditation has been associated with relatively reduced activity in the default mode network, a brain network implicated in self-related thinking and mind wandering. However, previous imaging studies have typically compared meditation to rest, despite other studies having reported differences in brain activation patterns between meditators and controls at rest. Moreover, rest is associated with a range of brain activation patterns across individuals that has only recently begun to be better characterized. Therefore, in this study we compared meditation to another active cognitive task, both to replicate the findings that meditation is associated with relatively reduced default mode network activity and to extend these findings by testing whether default mode activity was reduced during meditation, beyond the typical reductions observed during effortful tasks. In addition, prior studies had used small groups, whereas in the present study we tested these hypotheses in a larger group. The results indicated that meditation is associated with reduced activations in the default mode network, relative to an active task, for meditators as compared to controls. Regions of the default mode network showing a Group × Task interaction included the posterior cingulate/precuneus and anterior cingulate cortex. These findings replicate and extend prior work indicating that the suppression of default mode processing may represent a central neural process in long-term meditation, and they suggest that meditation leads to relatively reduced default mode processing beyond that observed during another active cognitive task.

  7. Batch Mode Active Sampling based on Marginal Probability Distribution Matching.

    PubMed

    Chattopadhyay, Rita; Wang, Zheng; Fan, Wei; Davidson, Ian; Panchanathan, Sethuraman; Ye, Jieping

    2012-01-01

    Active Learning is a machine learning and data mining technique that selects the most informative samples for labeling and uses them as training data; it is especially useful when there are large amount of unlabeled data and labeling them is expensive. Recently, batch-mode active learning, where a set of samples are selected concurrently for labeling, based on their collective merit, has attracted a lot of attention. The objective of batch-mode active learning is to select a set of informative samples so that a classifier learned on these samples has good generalization performance on the unlabeled data. Most of the existing batch-mode active learning methodologies try to achieve this by selecting samples based on varied criteria. In this paper we propose a novel criterion which achieves good generalization performance of a classifier by specifically selecting a set of query samples that minimizes the difference in distribution between the labeled and the unlabeled data, after annotation. We explicitly measure this difference based on all candidate subsets of the unlabeled data and select the best subset. The proposed objective is an NP-hard integer programming optimization problem. We provide two optimization techniques to solve this problem. In the first one, the problem is transformed into a convex quadratic programming problem and in the second method the problem is transformed into a linear programming problem. Our empirical studies using publicly available UCI datasets and a biomedical image dataset demonstrate the effectiveness of the proposed approach in comparison with the state-of-the-art batch-mode active learning methods. We also present two extensions of the proposed approach, which incorporate uncertainty of the predicted labels of the unlabeled data and transfer learning in the proposed formulation. Our empirical studies on UCI datasets show that incorporation of uncertainty information improves performance at later iterations while our studies on 20

  8. Multiple-Component Crystal Fabric Measurements from Acoustically-Generated Normal Modes in Borehole

    NASA Astrophysics Data System (ADS)

    Kluskiewicz, D. J.; Waddington, E. D.; McCarthy, M.; Anandakrishnan, S.; Voigt, D.; Matsuoka, K.

    2014-12-01

    Sound wave velocities in ice are a proxy of crystal orientation fabric. Because p- and s-waves respectively travel faster and slower in the direction of an ice crystal c-axis, the velocities of these waves in a fabric are related to the clustering of ice crystal c-axes in the direction of wave propagation. Previous sonic logs at Dome C, NGRIP, WAIS, and NEEM have inferred a single component fabric description from the velocities of vertically-propagating p-waves around each ice core borehole. These records supplement thin-section measurements of crystal fabric by sampling larger numbers of crystals in a depth-continuous log. Observations of azimuthally anisotropic vertical-girdle fabrics at ice-core sites such as WAIS, NGRIP, and EDML underly a benefit for logging methods that are sensitive to such fabrics. We present a theoretical framework for using borehole flexural modes to measure azimuthal crystal-fabric anisotropy, and describe ongoing efforts to develop a sonic logging tool for this purpose. We also present data from p-wave logs and thin section measurements at the WAIS Divide, and describe how a flexural wave log could supplement the existing measurements.

  9. Fourier transform infrared spectra and normal mode analysis of drug molecules: Zidovudine

    NASA Astrophysics Data System (ADS)

    Jain, Nivedita; Prabhakar, Santosh; Singh, R. A.

    2013-03-01

    The FTIR spectra of zidovudine molecule have been recorded in the range 4000-400 cm-1. The title compound is used as a drug against AIDS or HIV. The molecular structure, fundamental vibrational frequencies and intensities of vibrational bands are evaluated using density functional theory (DFT) using BLYP, B3LYP, B3PW91 and MPW1PW91 methods with 6-31+G(d,p) standard basis set. Comparison of simulated spectra with the experimental spectrum provides important informations and the ability of the computational method to describe the vibrational modes. These calculations have allowed finding most stable conformational structure of AZT. Calculated results of the title compound indicate that the drug molecule has syn orientation. The glycosidic bond in AZT and a minimum-energy structure in which the glycosy torsion angle χ and torsion angle γ values are consistent with those in the conformation of AZT in the AZT5-triphosphate bound to HIV RT is determined.

  10. Reduced hippocampal activity during encoding in cognitively normal adults carrying the APOE ε4 allele

    PubMed Central

    Adamson, Maheen M.; Hutchinson, J. Benjamin; Shelton, Amy; Wagner, Anthony D.; Taylor, Joy L.

    2011-01-01

    Apolipoprotein (APOE) ε4-related differences in memory performance have been detected before age 65. The hippocampus and the surrounding medial temporal lobe (MTL) structures are the first site affected by Alzheimer’s disease (AD) and the MTL is the seat of episodic memory, including visuo-spatial memory. While reports of APOE ε4-related differences in these brain structures are not consistent in either cross-sectional or longitudinal structural and functional magnetic resonance imaging (fMRI) studies, there is increasing evidence that brain activity at baseline (defined as activity during fixation or rest) may differ in APOE ε4 carriers compared to non-carriers. In this fMRI study, cognitively normal APOE ε4 carriers and non-carriers engaged in a perspective-dependent spatial learning task (Shelton and Gabrieli, 2002) previously shown to activate MTL structures in older participants (Borghesani et al., 2008). A low-level, visually engaging dot-control task was used for comparison, in addition to fixation. APOE ε4 carriers showed less activation than non-carriers in the hippocampus proper during encoding. Specifically, when spatial encoding was contrasted against the dot-control task, encoding-related activation was significantly lower in carriers than non-carriers. By contrast, no ε4-related differences in the hippocampus were found when spatial encoding was compared with fixation. Lower activation, however, was not global since encoding-related activation in early visual cortex (left lingual gyrus) was not different between APOE ε4 carriers and non-carriers. The present data document APOE ε4-related differences in the hippocampus proper during encoding and underscore the role of low-level control contrasts for complex encoding tasks. These results have implications for fMRI studies that investigate the default-mode network (DMN) in middle -aged to older APOE ε4 carriers to help evaluate AD risk in this otherwise cognitively normal population. PMID

  11. Resistive wall mode active control physics design for KSTAR

    SciTech Connect

    Park, Y. S. Sabbagh, S. A.; Bialek, J. M.; Berkery, J. W.; Bak, J. G.; Lee, S. G.; Oh, Y. K.

    2014-01-15

    As KSTAR H-mode operation approaches the region where the resistive wall mode (RWM) can be unstable, an important issue for future long pulse, high beta plasma operation is to evaluate RWM active feedback control performance using a planned active/passive RWM stabilization system on the device. In particular, an optimal design of feedback sensors allows mode stabilization up to the highest achievable β{sub N} close to the ideal with-wall limit, β{sub N}{sup wall}, with reduced control power requirements. The computed ideal n = 1 mode structure from the DCON code has been input to the VALEN-3D code to calculate the projected performance of an active RWM control system in the KSTAR three-dimensional conducting structure device geometry. Control performance with the midplane locked mode detection sensors, off-midplane saddle loops, and magnetic pickup coils is examined. The midplane sensors measuring the radial component of the mode perturbation is found to be strongly affected by the wall eddy current. The off-axis saddle loops with proper compensation of the prompt applied field are computed to provide stabilization at β{sub N} up to 86% of β{sub N}{sup wall} but the low RWM amplitude computed in the off-axis regions near the sensors can produce a low signal-to-noise ratio. The required control power and bandwidth are also estimated with varied noise levels in the feedback sensors. Further improvements have been explored by examining a new RWM sensor design motivated by the off-midplane poloidal magnetic field sensors in NSTX. The new sensors mounted off of the copper passive stabilizer plates near the device midplane show a clear advantage in control performance corresponding to achieving 99% of β{sub N}{sup wall} without the need of compensation of the prompt field. The result shows a significant improvement of RWM feedback stabilization using the new sensor set which motivates a future feedback sensor upgrade.

  12. HBT-EP Program: Active MHD Mode Dynamics and Control

    NASA Astrophysics Data System (ADS)

    Navratil, G. A.; Bialek, J.; Boozer, A. H.; Byrne, P. J.; Donald, G. V.; Hughes, P. E.; Levesque, J. P.; Mauel, M. E.; Peng, Q.; Rhodes, D. J.; Stoafer, C. C.; Hansen, C. J.

    2015-11-01

    The HBT-EP active mode control research program aims to: (i) quantify external kink dynamics and multimode response to magnetic perturbations, (ii) understand the relationship between control coil configuration, conducting and ferritic wall effects, and active feedback control, and (iii) explore advanced feedback algorithms. Biorthogonal decomposition is used to observe multiple simultaneous resistive wall modes (RWM). A 512 core GPU-based low latency (14 μs) MIMO control system uses 96 inputs and 64 outputs for Adaptive Control of RWMs. An in-vessel adjustable ferritic wall is used to study ferritic RWMs with increased growth rates, RMP response, and disruptivity. A biased electrode in the plasma is used to control the rotation of external kinks and evaluate error fields. A Thomson scattering diagnostic measures Te and ne at 3 spatial points, soon to be extended to 10 points. A quasi-linear sharp-boundary model of the plasma's multimode response to error fields is developed to determine harmful error field structures and associated NTV and resonant torques. Upcoming machine upgrades will allow measurements and control of scrape-off-layer currents, and control of kink modes using optical diagnostics. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  13. Active/passive mode-locked laser oscillator

    DOEpatents

    Fountain, William D.; Johnson, Bertram C.

    1977-01-01

    A Q-switched/mode-locked Nd:YAG laser oscillator employing simultaneous active (electro-optic) and passive (saturable absorber) loss modulation within the optical cavity is described. This "dual modulation" oscillator can produce transform-limited pulses of duration ranging from about 30 psec to about 5 nsec with greatly improved stability compared to other mode-locked systems. The pulses produced by this system lack intrapulse frequency or amplitude modulation, and hence are idealy suited for amplification to high energies and for other applications where well-defined pulses are required. Also, the pulses of this system have excellent interpulse characteristics, wherein the optical noise between the individual pulses of the pulse train has a power level well below the power of the peak pulse of the train.

  14. Depth classification of underwater targets based on complex acoustic intensity of normal modes

    NASA Astrophysics Data System (ADS)

    Yang, Guang; Yin, Jingwei; Yu, Yun; Shi, Zhenhua

    2016-04-01

    In order to solve the problem of depth classification of the underwater target in a very low frequency acoustic field, the active component of cross spectra of particle pressure and horizontal velocity (ACCSPPHV) is adopted to distinguish the surface vessel and the underwater target. According to the effective depth of a Pekeris waveguide, the placing depth forecasting equations of passive vertical double vector hydrophones are proposed. Numerical examples show that when the sum of depths of two hydrophones is the effective depth, the sign distribution of ACCSPPHV has nothing to do with horizontal distance; in addition, the sum of the first critical surface and the second critical surface is equal to the effective depth. By setting the first critical surface less than the difference between the effective water depth and the actual water depth, that is, the second critical surface is greater than the actual depth, the three positive and negative regions of the whole ocean volume are equivalent to two positive and negative regions and therefore the depth classification of the underwater target is obtained. Besides, when the 20 m water depth is taken as the first critical surface in the simulation of underwater targets (40 Hz, 50 Hz, and 60 Hz respectively), the effectiveness of the algorithm and the correctness of relevant conclusions are verified, and the analysis of the corresponding forecasting performance is conducted.

  15. ElNémo: a normal mode web server for protein movement analysis and the generation of templates for molecular replacement

    PubMed Central

    Suhre, Karsten; Sanejouand, Yves-Henri

    2004-01-01

    Normal mode analysis (NMA) is a powerful tool for predicting the possible movements of a given macromolecule. It has been shown recently that half of the known protein movements can be modelled by using at most two low-frequency normal modes. Applications of NMA cover wide areas of structural biology, such as the study of protein conformational changes upon ligand binding, membrane channel opening and closure, potential movements of the ribosome, and viral capsid maturation. Another, newly emerging field of NMA is related to protein structure determination by X-ray crystallography, where normal mode perturbed models are used as templates for diffraction data phasing through molecular replacement (MR). Here we present ElNémo, a web interface to the Elastic Network Model that provides a fast and simple tool to compute, visualize and analyse low-frequency normal modes of large macro-molecules and to generate a large number of different starting models for use in MR. Due to the ‘rotation-translation-block’ (RTB) approximation implemented in ElNémo, there is virtually no upper limit to the size of the proteins that can be treated. Upon input of a protein structure in Protein Data Bank (PDB) format, ElNémo computes its 100 lowest-frequency modes and produces a comprehensive set of descriptive parameters and visualizations, such as the degree of collectivity of movement, residue mean square displacements, distance fluctuation maps, and the correlation between observed and normal-mode-derived atomic displacement parameters (B-factors). Any number of normal mode perturbed models for MR can be generated for download. If two conformations of the same (or a homologous) protein are available, ElNémo identifies the normal modes that contribute most to the corresponding protein movement. The web server can be freely accessed at http://igs-server.cnrs-mrs.fr/elnemo/index.html. PMID:15215461

  16. Semianalytical quasi-normal mode theory for the local density of states in coupled photonic crystal cavity-waveguide structures.

    PubMed

    de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper; Gregersen, Niels

    2015-12-15

    We present and validate a semianalytical quasi-normal mode (QNM) theory for the local density of states (LDOS) in coupled photonic crystal (PhC) cavity-waveguide structures. By means of an expansion of the Green's function on one or a few QNMs, a closed-form expression for the LDOS is obtained, and for two types of two-dimensional PhCs, with one and two cavities side-coupled to an extended waveguide, the theory is validated against numerically exact computations. For the single cavity, a slightly asymmetric spectrum is found, which the QNM theory reproduces, and for two cavities, a nontrivial spectrum with a peak and a dip is found, which is reproduced only when including both the two relevant QNMs in the theory. In both cases, we find relative errors below 1% in the bandwidth of interest.

  17. Modeling protein conformational transitions by a combination of coarse-grained normal mode analysis and robotics-inspired methods

    PubMed Central

    2013-01-01

    Background Obtaining atomic-scale information about large-amplitude conformational transitions in proteins is a challenging problem for both experimental and computational methods. Such information is, however, important for understanding the mechanisms of interaction of many proteins. Methods This paper presents a computationally efficient approach, combining methods originating from robotics and computational biophysics, to model protein conformational transitions. The ability of normal mode analysis to predict directions of collective, large-amplitude motions is applied to bias the conformational exploration performed by a motion planning algorithm. To reduce the dimension of the problem, normal modes are computed for a coarse-grained elastic network model built on short fragments of three residues. Nevertheless, the validity of intermediate conformations is checked using the all-atom model, which is accurately reconstructed from the coarse-grained one using closed-form inverse kinematics. Results Tests on a set of ten proteins demonstrate the ability of the method to model conformational transitions of proteins within a few hours of computing time on a single processor. These results also show that the computing time scales linearly with the protein size, independently of the protein topology. Further experiments on adenylate kinase show that main features of the transition between the open and closed conformations of this protein are well captured in the computed path. Conclusions The proposed method enables the simulation of large-amplitude conformational transitions in proteins using very few computational resources. The resulting paths are a first approximation that can directly provide important information on the molecular mechanisms involved in the conformational transition. This approximation can be subsequently refined and analyzed using state-of-the-art energy models and molecular modeling methods. PMID:24564964

  18. Ultra-broadband dissipative soliton and noise-like pulse generation from a normal dispersion mode-locked Tm-doped all-fiber laser.

    PubMed

    Sobon, Grzegorz; Sotor, Jaroslaw; Martynkien, Tadeusz; Abramski, Krzysztof M

    2016-03-21

    We report generation of ultra-broadband dissipative solitons and noise-like pulses from a simple, fully fiberized mode-locked Tm-doped fiber laser. The oscillator operates in the normal net dispersion regime and is mode-locked via nonlinear polarization evolution. Depending on the cavity dispersion, the laser was capable of generating 60 nm or 100 nm broad dissipative solitons. These are the broadest spectra generated from a normal dispersion mode-locked Tm-doped fiber laser so far. The same oscillator might also operate in the noise-like pulse regime with extremely broad emission spectra (over 300 nm), which also significantly outperforms the previous reports.

  19. Elastic parabolic equation and normal mode solutions for seismo-acoustic propagation in underwater environments with ice covers.

    PubMed

    Collis, Jon M; Frank, Scott D; Metzler, Adam M; Preston, Kimberly S

    2016-05-01

    Sound propagation predictions for ice-covered ocean acoustic environments do not match observational data: received levels in nature are less than expected, suggesting that the effects of the ice are substantial. Effects due to elasticity in overlying ice can be significant enough that low-shear approximations, such as effective complex density treatments, may not be appropriate. Building on recent elastic seafloor modeling developments, a range-dependent parabolic equation solution that treats the ice as an elastic medium is presented. The solution is benchmarked against a derived elastic normal mode solution for range-independent underwater acoustic propagation. Results from both solutions accurately predict plate flexural modes that propagate in the ice layer, as well as Scholte interface waves that propagate at the boundary between the water and the seafloor. The parabolic equation solution is used to model a scenario with range-dependent ice thickness and a water sound speed profile similar to those observed during the 2009 Ice Exercise (ICEX) in the Beaufort Sea. PMID:27250161

  20. All-atom normal-mode analysis reveals an RNA-induced allostery in a bacteriophage coat protein

    NASA Astrophysics Data System (ADS)

    Dykeman, Eric C.; Twarock, Reidun

    2010-03-01

    Assembly of the T=3 bacteriophage MS2 is initiated by the binding of a 19 nucleotide RNA stem loop from within the phage genome to a symmetric coat protein dimer. This binding event effects a folding of the FG loop in one of the protein subunits of the dimer and results in the formation of an asymmetric dimer. Since both the symmetric and asymmetric forms of the dimer are needed for the assembly of the protein container, this allosteric switch plays an important role in the life cycle of the phage. We provide here details of an all-atom normal-mode analysis of this allosteric effect. The results suggest that asymmetric contacts between the A -duplex RNA phosphodiester backbone of the stem loop with the EF loop in one coat protein subunit results in an increased dynamic behavior of its FG loop. The four lowest-frequency modes, which encompass motions predominantly on the FG loops, account for over 90% of the increased dynamic behavior due to a localization of the vibrational pattern on a single FG loop. Finally, we show that an analysis of the allosteric effect using an elastic network model fails to predict this localization effect, highlighting the importance of using an all-atom full force field method for this problem.

  1. Elastic parabolic equation and normal mode solutions for seismo-acoustic propagation in underwater environments with ice covers.

    PubMed

    Collis, Jon M; Frank, Scott D; Metzler, Adam M; Preston, Kimberly S

    2016-05-01

    Sound propagation predictions for ice-covered ocean acoustic environments do not match observational data: received levels in nature are less than expected, suggesting that the effects of the ice are substantial. Effects due to elasticity in overlying ice can be significant enough that low-shear approximations, such as effective complex density treatments, may not be appropriate. Building on recent elastic seafloor modeling developments, a range-dependent parabolic equation solution that treats the ice as an elastic medium is presented. The solution is benchmarked against a derived elastic normal mode solution for range-independent underwater acoustic propagation. Results from both solutions accurately predict plate flexural modes that propagate in the ice layer, as well as Scholte interface waves that propagate at the boundary between the water and the seafloor. The parabolic equation solution is used to model a scenario with range-dependent ice thickness and a water sound speed profile similar to those observed during the 2009 Ice Exercise (ICEX) in the Beaufort Sea.

  2. Mechanisms for multiple activity modes of VTA dopamine neurons

    PubMed Central

    Oster, Andrew; Faure, Philippe; Gutkin, Boris S.

    2015-01-01

    Midbrain ventral segmental area (VTA) dopaminergic neurons send numerous projections to cortical and sub-cortical areas, and diffusely release dopamine (DA) to their targets. DA neurons display a range of activity modes that vary in frequency and degree of burst firing. Importantly, DA neuronal bursting is associated with a significantly greater degree of DA release than an equivalent tonic activity pattern. Here, we introduce a single compartmental, conductance-based computational model for DA cell activity that captures the behavior of DA neuronal dynamics and examine the multiple factors that underlie DA firing modes: the strength of the SK conductance, the amount of drive, and GABA inhibition. Our results suggest that neurons with low SK conductance fire in a fast firing mode, are correlated with burst firing, and require higher levels of applied current before undergoing depolarization block. We go on to consider the role of GABAergic inhibition on an ensemble of dynamical classes of DA neurons and find that strong GABA inhibition suppresses burst firing. Our studies suggest differences in the distribution of the SK conductance and GABA inhibition levels may indicate subclasses of DA neurons within the VTA. We further identify, that by considering alternate potassium dynamics, the dynamics display burst patterns that terminate via depolarization block, akin to those observed in vivo in VTA DA neurons and in substantia nigra pars compacta (SNc) DA cell preparations under apamin application. In addition, we consider the generation of transient burst firing events that are NMDA-initiated or elicited by a sudden decrease of GABA inhibition, that is, disinhibition. PMID:26283955

  3. High-latitude filtering in a global grid-point model using model normal modes. [Fourier filters for synoptic weather forecasting

    NASA Technical Reports Server (NTRS)

    Takacs, L. L.; Kalnay, E.; Navon, I. M.

    1985-01-01

    A normal modes expansion technique is applied to perform high latitude filtering in the GLAS fourth order global shallow water model with orography. The maximum permissible time step in the solution code is controlled by the frequency of the fastest propagating mode, which can be a gravity wave. Numerical methods are defined for filtering the data to identify the number of gravity modes to be included in the computations in order to obtain the appropriate zonal wavenumbers. The performances of the model with and without the filter, and with a time tendency and a prognostic field filter are tested with simulations of the Northern Hemisphere winter. The normal modes expansion technique is shown to leave the Rossby modes intact and permit 3-5 day predictions, a range not possible with the other high-latitude filters.

  4. Generation of dissipative solitons in an actively mode-locked ultralong fibre laser

    SciTech Connect

    Koliada, N A; Nyushkov, B N; Ivanenko, A V; Kobtsev, Sergey M; Harper, Paul; Turitsyn, Sergei K; Denisov, Vladimir I; Pivtsov, V S

    2013-02-28

    A single-pulse actively mode-locked fibre laser with a cavity length exceeding 1 km has been developed and investigated for the first time. This all-fibre erbium-doped laser has a normal intracavity dispersion and generates dissipative 8-ns solitons with a fundamental repetition rate of 163.8 kHz; the energy per pulse reaches 34 nJ. The implemented mode locking, based on the use of intracavity intensity modulator, provides self-triggering and high stability of pulsed lasing. A possibility of continuous tuning of the centre lasing wavelength in the range of 1558 - 1560 nm without any tunable spectral selective elements in the cavity is demonstrated. The tuning occurs when controlling the modulation signal frequency due to the forced change in the pulse repetition time (group delay) under the conditions of intracavity chromatic dispersion. (laser optics 2012)

  5. Tectonic activity and structural features of active intracontinental normal faults in the Weihe Graben, central China

    NASA Astrophysics Data System (ADS)

    Rao, Gang; Lin, Aiming; Yan, Bing; Jia, Dong; Wu, Xiaojun

    2014-12-01

    This study examines the tectonic activity and structural features of active normal faults in the Weihe Graben, central China. The Weihe Graben is an area with a high level of historic seismicity, and it is one of the intracontinental systems that developed since Tertiary in the extensional environment around the Ordos Block. Analysis of high-resolution remote-sensing imagery data, field observations, and radiocarbon dating results reveal the following: i) active normal faults are mainly developed within a zone < 500 m wide along the southern border of the eastern part of the Weihe Graben; ii) the active faults that have been identified are characterized by stepwise fault scarps dipping into the graben at angles of 40°-71°; iii) there are numerous discontinuous individual fault traces, ranging in length from a few tens of meters to 450 m (generally < 200 m); iv) fault zone structures, topographic features, and fault striations on the main fault planes indicate almost pure normal-slip; and v) late Pleistocene-Holocene terrace risers, loess, and alluvial deposits have been vertically offset by up to ~ 80 m, with a non-uniform dip-slip rate (throw-rates) ranging from ~ 2.1 to 5.7 mm/yr, mostly 2-3 mm/yr. Our results reveal that active normal faults have been developing in the Weihe Graben under an ongoing extensional environment, probably associated with the pre-existing graben and spreading of the continental crust, and this is in contrast with the Ordos Block and neighboring orogenic regions. These results provide new insights into the nature of extensional tectonic deformation in intracontinental graben systems.

  6. Distinguishing fall activities from normal activities by angular rate characteristics and high-speed camera characterization.

    PubMed

    Nyan, M N; Tay, F E H; Tan, A W Y; Seah, K H W

    2006-10-01

    Distinguishing sideways and backward falls from normal activities of daily living using angular rate sensors (gyroscopes) was explored in this paper. Gyroscopes were secured on a shirt at the positions of sternum (S), front of the waist (FW) and right underarm (RU) to measure angular rate in lateral and sagittal planes of the body during falls and normal activities. Moreover, the motions of the fall incidents were captured by a high-speed camera at a frame rate of 250 frames per second (fps) to study the body configuration during fall. The high-speed camera and the sensor data capture system were activated simultaneously to synchronize the picture frame of high-speed camera and the sensor data. The threshold level for each sensor was set to distinguish fall activities from normal activities. Lead time of fall activities (time after threshold value is surpassed to the time when the hip hits the ground) and relative angle of body configuration (angle beta between the vertical line and the line from the center point of the foot or the center point between the two legs to that of the waist) at the threshold level were studied. For sideways falls, lead times of sensors at positions FW and S were about 200-220ms and 135-182ms, respectively. The lead time of the slippery backward fall (about 98ms) from the sensor at position RU was shorter than that of the sideways falls from the sensors at positions FW and S. The relative angle of body configuration at threshold level for sideways and backward falls were about 40-43 degrees for the sensor at position FW, about 43-52 degrees for the sensor at position S and about 54 degrees for the sensor at position RU, respectively. This is the first study that investigates fall dynamics in detection of fall before the person hits the ground using angular rate sensors (gyroscopes). PMID:16406739

  7. cNMA: a framework of encounter complex-based normal mode analysis to model conformational changes in protein interactions

    PubMed Central

    Oliwa, Tomasz; Shen, Yang

    2015-01-01

    Motivation: It remains both a fundamental and practical challenge to understand and anticipate motions and conformational changes of proteins during their associations. Conventional normal mode analysis (NMA) based on anisotropic network model (ANM) addresses the challenge by generating normal modes reflecting intrinsic flexibility of proteins, which follows a conformational selection model for protein–protein interactions. But earlier studies have also found cases where conformational selection alone could not adequately explain conformational changes and other models have been proposed. Moreover, there is a pressing demand of constructing a much reduced but still relevant subset of protein conformational space to improve computational efficiency and accuracy in protein docking, especially for the difficult cases with significant conformational changes. Method and results: With both conformational selection and induced fit models considered, we extend ANM to include concurrent but differentiated intra- and inter-molecular interactions and develop an encounter complex-based NMA (cNMA) framework. Theoretical analysis and empirical results over a large data set of significant conformational changes indicate that cNMA is capable of generating conformational vectors considerably better at approximating conformational changes with contributions from both intrinsic flexibility and inter-molecular interactions than conventional NMA only considering intrinsic flexibility does. The empirical results also indicate that a straightforward application of conventional NMA to an encounter complex often does not improve upon NMA for an individual protein under study and intra- and inter-molecular interactions need to be differentiated properly. Moreover, in addition to induced motions of a protein under study, the induced motions of its binding partner and the coupling between the two sets of protein motions present in a near-native encounter complex lead to the improved

  8. Platelet Serotonin Transporter Function Predicts Default-Mode Network Activity

    PubMed Central

    Kasess, Christian H.; Meyer, Bernhard M.; Hofmaier, Tina; Diers, Kersten; Bartova, Lucie; Pail, Gerald; Huf, Wolfgang; Uzelac, Zeljko; Hartinger, Beate; Kalcher, Klaudius; Perkmann, Thomas; Haslacher, Helmuth; Meyer-Lindenberg, Andreas; Kasper, Siegfried; Freissmuth, Michael; Windischberger, Christian; Willeit, Matthäus; Lanzenberger, Rupert; Esterbauer, Harald; Brocke, Burkhard; Moser, Ewald; Sitte, Harald H.; Pezawas, Lukas

    2014-01-01

    Background The serotonin transporter (5-HTT) is abundantly expressed in humans by the serotonin transporter gene SLC6A4 and removes serotonin (5-HT) from extracellular space. A blood-brain relationship between platelet and synaptosomal 5-HT reuptake has been suggested, but it is unknown today, if platelet 5-HT uptake can predict neural activation of human brain networks that are known to be under serotonergic influence. Methods A functional magnetic resonance study was performed in 48 healthy subjects and maximal 5-HT uptake velocity (Vmax) was assessed in blood platelets. We used a mixed-effects multilevel analysis technique (MEMA) to test for linear relationships between whole-brain, blood-oxygen-level dependent (BOLD) activity and platelet Vmax. Results The present study demonstrates that increases in platelet Vmax significantly predict default-mode network (DMN) suppression in healthy subjects independent of genetic variation within SLC6A4. Furthermore, functional connectivity analyses indicate that platelet Vmax is related to global DMN activation and not intrinsic DMN connectivity. Conclusion This study provides evidence that platelet Vmax predicts global DMN activation changes in healthy subjects. Given previous reports on platelet-synaptosomal Vmax coupling, results further suggest an important role of neuronal 5-HT reuptake in DMN regulation. PMID:24667541

  9. Nonwoven fabric active electrodes for biopotential measurement during normal daily activity.

    PubMed

    Kang, Tae-Ho; Merritt, Carey R; Grant, Edward; Pourdeyhimi, Behnam; Nagle, H Troy

    2008-01-01

    Body movement is responsible for most of the interference during physiological data acquisition during normal daily activities. In this paper, we introduce nonwoven fabric active electrodes that provide the comfort required for clothing while robustly recording physiological data in the presence of body movement. The nonwoven fabric active electrodes were designed and fabricated using both hand- and screen-printing thick-film techniques. Nonstretchable nonwoven (Evolon 100) was chosen as the flexible fabric substrate and a silver filled polymer ink (Creative Materials CMI 112-15) was used to form a transducer layer and conductive lines on the nonwoven fabrics. These nonwoven fabric active electrodes can be easily integrated into clothing for wearable health monitoring applications. Test results indicate that nonwoven textile-based sensors show considerable promise for physiological data acquisition in wearable healthcare monitoring applications.

  10. [The gaze and functional hemispheric activation in normal subjects].

    PubMed

    Gallois, P; Hautecoeur, P; Ovelacq, E; Gras, P; Dereux, J F

    1985-01-01

    The aim of this work was to determine whether the study of lateral and vertical conjugated eye movement could serve as an indicator of the functional hemispheric activation. Questions of vocabulary, calculation, logic (V.C.L.) and visuo-spatial instructions, as well as music-listening (V.S.M.), were proposed to 60 control subjects (21 men, 39 women). They were divided in 4 groups of 15 according to their laterality (complete right handed, incomplete right handed, ambidextrous, left handed). Eye movements were recorded using a video system. Deviations of the eyes towards the right and left, upwards and downwards, as well as episodes of staring were noted. Concerning V.C.L. questions, there was a significant correlation between conjugated lateral eye movements and the contralateral hemisphere activation. The study of vertical eye movements revealed a correlation only in complete right-handed and left-handed subjects: deviation upwards during the left hemisphere activation, and downwards during the right hemisphere activation. This pattern of response was no longer found during V.S.M. questions which, in the 4 groups, evoked staring episodes in 56 to 72 per cent of the cases. The negative emotional stimuli (emotional words, non verbal stimuli, stressful situations) evoked preferentially, but independently of laterality, deviations towards the left and downwards in favor of the right hemisphere activation. This method of observation of eye movements seems therefore of significant interest in Neuropsychology, provided that methodologic rules are rigorously respected.

  11. Diagnostic for two-mode variable valve activation device

    SciTech Connect

    Fedewa, Andrew M

    2014-01-07

    A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

  12. Aligning Experimental and Theoretical Anisotropic B-Factors: Water Models, Normal-Mode Analysis Methods, and Metrics

    PubMed Central

    2014-01-01

    The strength of X-ray crystallography in providing the information for protein dynamics has been under appreciated. The anisotropic B-factors (ADPs) from high-resolution structures are invaluable in studying the relationship among structure, dynamics, and function. Here, starting from an in-depth evaluation of the metrics used for comparing the overlap between two ellipsoids, we applied normal-mode analysis (NMA) to predict the theoretical ADPs and then align them with experimental results. Adding an extra layer of explicitly treated water on protein surface significantly improved the energy minimization results and better reproduced the anisotropy of experimental ADPs. In comparing experimental and theoretical ADPs, we focused on the overlap in shape, the alignment of dominant directions, and the similarity in magnitude. The choices of water molecules, NMA methods, and the metrics for evaluating the overlap of ADPs determined final results. This study provides useful information for exploring the physical basis and the application potential of experimental ADPs. PMID:24673391

  13. Default-mode-like network activation in awake rodents.

    PubMed

    Upadhyay, Jaymin; Baker, Scott J; Chandran, Prasant; Miller, Loan; Lee, Younglim; Marek, Gerard J; Sakoglu, Unal; Chin, Chih-Liang; Luo, Feng; Fox, Gerard B; Day, Mark

    2011-01-01

    During wakefulness and in absence of performing tasks or sensory processing, the default-mode network (DMN), an intrinsic central nervous system (CNS) network, is in an active state. Non-human primate and human CNS imaging studies have identified the DMN in these two species. Clinical imaging studies have shown that the pattern of activity within the DMN is often modulated in various disease states (e.g., Alzheimer's, schizophrenia or chronic pain). However, whether the DMN exists in awake rodents has not been characterized. The current data provides evidence that awake rodents also possess 'DMN-like' functional connectivity, but only subsequent to habituation to what is initially a novel magnetic resonance imaging (MRI) environment as well as physical restraint. Specifically, the habituation process spanned across four separate scanning sessions (Day 2, 4, 6 and 8). At Day 8, significant (p<0.05) functional connectivity was observed amongst structures such as the anterior cingulate (seed region), retrosplenial, parietal, and hippocampal cortices. Prior to habituation (Day 2), functional connectivity was only detected (p<0.05) amongst CNS structures known to mediate anxiety (i.e., anterior cingulate (seed region), posterior hypothalamic area, amygdala and parabracial nucleus). In relating functional connectivity between cingulate-default-mode and cingulate-anxiety structures across Days 2-8, a significant inverse relationship (r = -0.65, p = 0.0004) was observed between these two functional interactions such that increased cingulate-DMN connectivity corresponded to decreased cingulate anxiety network connectivity. This investigation demonstrates that the cingulate is an important component of both the rodent DMN-like and anxiety networks.

  14. From Dark to Bright: First-Order Perturbation Theory with Analytical Mode Normalization for Plasmonic Nanoantenna Arrays Applied to Refractive Index Sensing.

    PubMed

    Weiss, T; Mesch, M; Schäferling, M; Giessen, H; Langbein, W; Muljarov, E A

    2016-06-10

    We present a first-order perturbation theory to calculate the frequency shift and linewidth change of photonic resonances in one- and two-dimensional periodic structures under modifications of the surrounding refractive index. Our method is based on the resonant state expansion, for which we extend the analytical mode normalization to periodic structures. We apply this theory to calculate the sensitivity of bright dipolar and much darker quadrupolar plasmonic modes by determining the maximum shift and optimal sensing volume. PMID:27341256

  15. From Dark to Bright: First-Order Perturbation Theory with Analytical Mode Normalization for Plasmonic Nanoantenna Arrays Applied to Refractive Index Sensing

    NASA Astrophysics Data System (ADS)

    Weiss, T.; Mesch, M.; Schäferling, M.; Giessen, H.; Langbein, W.; Muljarov, E. A.

    2016-06-01

    We present a first-order perturbation theory to calculate the frequency shift and linewidth change of photonic resonances in one- and two-dimensional periodic structures under modifications of the surrounding refractive index. Our method is based on the resonant state expansion, for which we extend the analytical mode normalization to periodic structures. We apply this theory to calculate the sensitivity of bright dipolar and much darker quadrupolar plasmonic modes by determining the maximum shift and optimal sensing volume.

  16. Actively mode-locked all fiber laser with cylindrical vector beam output.

    PubMed

    Zhou, Yong; Wang, Anting; Gu, Chun; Sun, Biao; Xu, Lixin; Li, Feng; Chung, Dick; Zhan, Qiwen

    2016-02-01

    We demonstrated an all fiber actively mode-locked laser that emits a cylindrical vector beam. An intra-cavity few-mode fiber Bragg grating inscribed in a short section of four-mode fiber is employed to provide mode selection and spectrum filtering functions. Mode coupling is achieved by offset splicing between the single-mode fiber and the four-mode fiber in the laser cavity. A LiNbO3 Mach-Zehnder modulator is used to achieve active mode-locking in the laser. The laser operates at 1547 nm with 30 dB spectrum width of 0.2 nm. The mode-locked pulses have a duration of 2 ns and repetition of 12.06 MHz. Through adjusting the polarization state in the laser cavity, both radially and azimuthally polarized beams have been obtained with high mode purity.

  17. Actively mode-locked all fiber laser with cylindrical vector beam output.

    PubMed

    Zhou, Yong; Wang, Anting; Gu, Chun; Sun, Biao; Xu, Lixin; Li, Feng; Chung, Dick; Zhan, Qiwen

    2016-02-01

    We demonstrated an all fiber actively mode-locked laser that emits a cylindrical vector beam. An intra-cavity few-mode fiber Bragg grating inscribed in a short section of four-mode fiber is employed to provide mode selection and spectrum filtering functions. Mode coupling is achieved by offset splicing between the single-mode fiber and the four-mode fiber in the laser cavity. A LiNbO3 Mach-Zehnder modulator is used to achieve active mode-locking in the laser. The laser operates at 1547 nm with 30 dB spectrum width of 0.2 nm. The mode-locked pulses have a duration of 2 ns and repetition of 12.06 MHz. Through adjusting the polarization state in the laser cavity, both radially and azimuthally polarized beams have been obtained with high mode purity. PMID:26907420

  18. Enhanced Power Within the Default Mode Network in Normal Subjects with Elevated Scores on an Egocentric Scale

    PubMed Central

    Collins, Mark W.G; Persinger, Michael A

    2014-01-01

    Integrated global power from the primary structures that composed the Default Mode Network (DMN) and from a random collection of other structures were measured by sLORETA (standardized low-resolution electromagnetic tomography) for young university volunteers who had completed an inventory that contained a subscale by which egocentricity has been inferred. Subjects who exhibited higher scores for egocentricity displayed significantly more power within the DMN structures relative to comparison areas. This was not observed for individuals whose egocentricity scores were lowest where the power differences between the DMN and comparison structures were not significant statistically. DMN power was greater in the right hemisphere than the left for men but greater in the left hemisphere than the right for women. The results are consistent with our operating metaphor that elevation of power or activity within the DMN is associated with greater affiliation with the self and its cognitive contents. PMID:25419254

  19. Active noise control using a distributed mode flat panel loudspeaker.

    PubMed

    Zhu, H; Rajamani, R; Dudney, J; Stelson, K A

    2003-07-01

    A flat panel distributed mode loudspeaker (DML) has many advantages over traditional cone speakers in terms of its weight, size, and durability. However, its frequency response is uneven and complex, thus bringing its suitability for active noise control (ANC) under question. This paper presents experimental results demonstrating the effective use of panel DML speakers in an ANC application. Both feedback and feedforward control techniques are considered. Effective feedback control with a flat panel speaker could open up a whole range of new noise control applications and has many advantages over feedforward control. The paper develops a new control algorithm to attenuate tonal noise of a known frequency by feedback control. However, due to the uneven response of the speakers, feedback control is found to be only moderately effective even for this narrow-band application. Feedforward control proves to be most capable for the flat panel speaker. Using feedforward control, the sound pressure level can be significantly reduced in close proximity to an error microphone. The paper demonstrates an interesting application of the flat panel in which the panel is placed in the path of sound and effectively used to block sound transmission using feedforward control. This is a new approach to active noise control enabled by the use of flat panels and can be used to prevent sound from entering into an enclosure in the first place rather than the traditional approach of attempting to cancel sound after it enters the enclosure.

  20. Modeling G protein-coupled receptors for structure-based drug discovery using low-frequency normal modes for refinement of homology models: application to H3 antagonists.

    PubMed

    Rai, Brajesh K; Tawa, Gregory J; Katz, Alan H; Humblet, Christine

    2010-02-01

    G Protein-Coupled Receptors (GPCRs) are integral membrane proteins that play important role in regulating key physiological functions, and are targets of about 50% of all recently launched drugs. High-resolution experimental structures are available only for very few GPCRs. As a result, structure-based drug design efforts for GPCRs continue to rely on in silico modeling, which is considered to be an extremely difficult task especially for these receptors. Here, we describe Gmodel, a novel approach for building 3D atomic models of GPCRs using a normal mode-based refinement of homology models. Gmodel uses a small set of relevant low-frequency vibrational modes derived from Random Elastic Network model to efficiently sample the large-scale receptor conformation changes and generate an ensemble of alternative models. These are used to assemble receptor-ligand complexes by docking a known active into each of the alternative models. Each of these is next filtered using restraints derived from known mutation and binding affinity data and is refined in the presence of the active ligand. In this study, Gmodel was applied to generate models of the antagonist form of histamine 3 (H3) receptor. The validity of this novel modeling approach is demonstrated by performing virtual screening (using the refined models) that consistently produces highly enriched hit lists. The models are further validated by analyzing the available SAR related to classical H3 antagonists, and are found to be in good agreement with the available experimental data, thus providing novel insights into the receptor-ligand interactions.

  1. Transform-limited pulse generation in normal cavity dispersion erbium doped single-walled carbon nanotubes mode-locked fiber ring laser.

    PubMed

    Chernysheva, M A; Krylov, A A; Ogleznev, A A; Arutyunyan, N R; Pozharov, A S; Obraztsova, E D; Dianov, E M

    2012-10-01

    We demonstrate an erbium doped fiber ring laser mode-locked with a carboxymetylcellulose high-optical quality film with dispersed single-walled carbon nanotubes (SWCNT). The laser with large normal net cavity dispersion generates near bandwidth-limited picosecond inverse modified soliton pulses at 1.56 µm.

  2. Ultra-broadband dissipative soliton and noise-like pulse generation from a normal dispersion mode-locked Tm-doped all-fiber laser.

    PubMed

    Sobon, Grzegorz; Sotor, Jaroslaw; Martynkien, Tadeusz; Abramski, Krzysztof M

    2016-03-21

    We report generation of ultra-broadband dissipative solitons and noise-like pulses from a simple, fully fiberized mode-locked Tm-doped fiber laser. The oscillator operates in the normal net dispersion regime and is mode-locked via nonlinear polarization evolution. Depending on the cavity dispersion, the laser was capable of generating 60 nm or 100 nm broad dissipative solitons. These are the broadest spectra generated from a normal dispersion mode-locked Tm-doped fiber laser so far. The same oscillator might also operate in the noise-like pulse regime with extremely broad emission spectra (over 300 nm), which also significantly outperforms the previous reports. PMID:27136809

  3. Herbicide activity of monosulfuron and its mode of action.

    PubMed

    Fan, Zhi-Jin; Ai, Ying-Wei; Qian, Chuan-Fan; Li, Zheng-Ming

    2005-01-01

    Monosulfuron was developed for weed control in the field of wheat (Triticum, aestivum L.) and millet (Panicum miliaceum L.) with the application rate ranging from 15 to 60 g ai/hm2. Herbicidal activity of monosulfuron was evaluated systematically by bioassay using maize (Zea mays L.) taproot as indicator and weed fresh weight of Acalypha australis L. and Echinochloa phyllopogon. Maize CAU 3138 was the most tolerant cultivars to monosulfuron with IC50 (concentration of 50% inhibition) of 85 microg/kg, Yedan 13 was one of the most sensitive cultivars to monosulfuron with IC50 of 6.4 microg/kg. Monosulfuron inhibited the growth of Acalypha australis L. strongly comparing with that of Echinochloa phyllopogon. Monosulfuron was a good acetolactate synthase (ALS) inhibitor in vitro, the I50 (50% of inhibition) of monosulfuron, chlorsulfuron, tribenuron-methyl and nicosulfuron for CAU 3138 were 32, 2, 19 and 26 nmol/L respectively, for Yedan 13 the I50 were 15, 3, 17 and 65 nmol/L respectively. In vivo ALS inhibition occurred only in higher concentration of 4 sulfonylurea herbicide tested. Comparison study of this test indicated that the mode of action of monosulfuron was the same as that of other sulfonylurea herbicides such as chlorsulfuron, tribenuron-methyl and nicosulfuron, they were all inhibitors targeted at the ALS. PMID:16083111

  4. Modes of action of three disinfectant active substances: a review.

    PubMed

    Wessels, Stephen; Ingmer, Hanne

    2013-12-01

    This review deals with three categories of active substances for disinfectant products, their modes of action (MOA), and how MOA can help predict propensity for resistance in microorganisms. Within the European Union applications for approval of disinfectants of all kinds must be submitted in a few years, and documentation on MOA and resistance must be part of those applications. Peracetic acid is an unspecific, pervasive oxidizer of C-C double bonds and reduced atoms. This MOA would imply poor chance for development of resistance in microorganisms, as borne out by the absence of such reports in the literature. The quaternary ammonium compounds (QAC's) are much more specific in their antimicrobial mechanism. Even very low concentrations cause damage to the cytoplasmic membrane due to perturbation of the bilayers by the molecules' alkyl chains. Development of microbial resistance to QAC's, as well as cross-resistance to antibiotics, are particularly well documented. The polymer PHMB is antimicrobial because it disturbs the cell membrane's bilayer by interacting with it along the surface of the membrane. Resistance to the polymer appears not to develop despite many years of use in many fields. However, PHMB's toxicity to humans upon inhalation dictates great caution when deploying the substance.

  5. Risk of COPD with obstruction in active smokers with normal spirometry and reduced diffusion capacity.

    PubMed

    Harvey, Ben-Gary; Strulovici-Barel, Yael; Kaner, Robert J; Sanders, Abraham; Vincent, Thomas L; Mezey, Jason G; Crystal, Ronald G

    2015-12-01

    Smokers are assessed for chronic obstructive pulmonary disease (COPD) using spirometry, with COPD defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as airflow limitation that is not fully reversible with bronchodilators. There is a subset of smokers with normal spirometry (by GOLD criteria), who have a low diffusing capacity of the lung for carbon monoxide (DLCO), a parameter linked to emphysema and small airway disease. The natural history of these "normal spirometry/low DLCO" smokers is unknown.From a cohort of 1570 smokers in the New York City metropolitian area, all of whom had normal spirometry, two groups were randomly selected for lung function follow-up: smokers with normal spirometry/normal DLCO (n=59) and smokers with normal spirometry/low DLCO (n=46). All had normal history, physical examination, complete blood count, urinalysis, HIV status, α1-antitrypsin level, chest radiography, forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC ratio and total lung capacity. Throughout the study, all continued to be active smokers.In the normal spirometry/normal DLCO group assessed over 45±20 months, 3% developed GOLD-defined COPD. In contrast, in the normal spirometry/low DLCO group, followed over 41±31 months, 22% developed GOLD-defined COPD.Despite appearing "normal" according to GOLD, smokers with normal spirometry but low DLCO are at significant risk of developing COPD with obstruction to airflow.

  6. Empirical relations to determine the normalized spot size of a single-mode trapezoidal index fiber and computation of its propagation characteristics

    NASA Astrophysics Data System (ADS)

    Mallick, Aswini Kumar; Sarkar, Somenath

    2014-07-01

    Simple and complete empirical relations are presented here to determine a normalized spot size in terms of normalized frequencies over a long range and aspect ratio of a trapezoidal index single-mode fiber considering Gaussian approximation of the fundamental mode following the Marcuse method for the first time. After verification of their validity for arbitrary values of aspect ratio and normalized frequency, we calculate various propagation characteristics viz. dispersion and splice loss by using our formulations. Upon comparison, we observe an excellent match and the validity of our results with exact values and other results available in the literature. These formulas should attract the attention of experimentalists as a simple alternative to the rigorous methods of estimating the propagation characteristics of such fibers.

  7. High frequency normal mode statistics in a shallow water waveguide: the effect of random linear internal waves.

    PubMed

    Raghukumar, Kaustubha; Colosi, John A

    2014-07-01

    Using transport theory and Monte Carlo numerical simulation, the statistical properties of mode propagation at a frequency of 1 kHz are studied in a shallow water environment with random sound-speed perturbations from linear internal waves. The environment is typical of summer conditions in the mid-Atlantic bight during the Shallow Water 2006 experiment. Observables of interest include the second and fourth moments of the mode amplitudes, which are relevant to full-field mean intensity and scintillation index. It is found that mode phase randomization has a strong adiabatic component while at the same time mode coupling rates are significant. As a consequence, a computationally efficient transport theory is presented, which models cross-mode correlation adiabatically, but accounts for mode coupling using the mode energy equations of Creamer [(1996). J. Acoust. Soc. Am. 99, 2825-2838]. The theory also has closed-form expressions for the internal wave scattering matrix and a correction for an edge effect. The hybrid transport theory is shown to accurately reproduce many statistical quantities from the Monte Carlo simulations.

  8. Angular dependence of source-target-detector in active mode standoff infrared detection

    NASA Astrophysics Data System (ADS)

    Pacheco-Londoño, Leonardo C.; Castro-Suarez, John R.; Aparicio-Bolaños, Joaquín. A.; Hernández-Rivera, Samuel P.

    2013-06-01

    Active mode standoff measurement using infrared spectroscopy were carried out in which the angle between target and the source was varied from 0-70° with respect to the surface normal of substrates containing traces of highly energetic materials (explosives). The experiments were made using three infrared sources: a modulated source (Mod-FTIR), an unmodulated source (UnMod-FTIR) and a scanning quantum cascade laser (QCL), part of a dispersive mid infrared (MIR) spectrometer. The targets consisted of PENT 200 μg/cm2 deposited on aluminum plates placed at 1 m from the sources. The evaluation of the three modalities was aimed at verifying the influence of the highly collimated laser beam in the detection in comparison with the other sources. The Mod-FTIR performed better than QCL source in terms of the MIR signal intensity decrease with increasing angle.

  9. Steady-state entanglement and normal-mode splitting in an atom-assisted optomechanical system with intensity-dependent coupling

    SciTech Connect

    Barzanjeh, Sh.; Naderi, M. H.; Soltanolkotabi, M.

    2011-12-15

    In this paper, we study theoretically bipartite and tripartite continuous variable entanglement as well as normal-mode splitting in a single-atom cavity optomechanical system with intensity-dependent coupling. The system under consideration is formed by a Fabry-Perot cavity with a thin vibrating end mirror and a two-level atom in the Gaussian standing wave of the cavity mode. We first derive the general form of the Hamiltonian describing the tripartite intensity-dependent atom-field-mirror coupling due to the presence of the cavity mode structure. We then restrict our treatment to the first vibrational sideband of the mechanical resonator and derive a tripartite atom-field-mirror Hamiltonian. We show that when the optical cavity is intensely driven, one can generate bipartite entanglement between any pair in the tripartite system and that, due to entanglement sharing, atom-mirror entanglement is efficiently generated at the expense of optical-mechanical and optical-atom entanglement. We also find that in such a system, when the Lamb-Dicke parameter is large enough, one can simultaneously observe the normal mode splitting into three modes.

  10. Effect of damping on excitability of high-order normal modes. [for a large space telescope spacecraft

    NASA Technical Reports Server (NTRS)

    Merchant, D. H.; Gates, R. M.; Straayer, J. W.

    1975-01-01

    The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs.

  11. Mode-locked femtosecond all-normal all-PM Yb-doped fiber laser using a nonlinear amplifying loop mirror.

    PubMed

    Aguergaray, Claude; Broderick, Neil G R; Erkintalo, Miro; Chen, Jocelyn S Y; Kruglov, Vladimir

    2012-05-01

    We report on a new design for a passively mode locked fibre laser employing all normal dispersion polarisation maintaining fibres operating at 1 μm. The laser produces linearly polarized, linearly chirped pulses that can be recompressed down to 344 fs. Compared to previous laser designs the cavity is mode-locked using a nonlinear amplifying fibre loop mirror that provides an additional degree of freedom allowing easy control over the pulse parameters. This is a robust laser design with excellent reliability and lifetime.

  12. Differential Lipid Profiles of Normal Human Brain Matter and Gliomas by Positive and Negative Mode Desorption Electrospray Ionization – Mass Spectrometry Imaging

    PubMed Central

    Pirro, Valentina; Hattab, Eyas M.; Cohen-Gadol, Aaron A.; Cooks, R. Graham

    2016-01-01

    Desorption electrospray ionization—mass spectrometry (DESI-MS) imaging was used to analyze unmodified human brain tissue sections from 39 subjects sequentially in the positive and negative ionization modes. Acquisition of both MS polarities allowed more complete analysis of the human brain tumor lipidome as some phospholipids ionize preferentially in the positive and others in the negative ion mode. Normal brain parenchyma, comprised of grey matter and white matter, was differentiated from glioma using positive and negative ion mode DESI-MS lipid profiles with the aid of principal component analysis along with linear discriminant analysis. Principal component–linear discriminant analyses of the positive mode lipid profiles was able to distinguish grey matter, white matter, and glioma with an average sensitivity of 93.2% and specificity of 96.6%, while the negative mode lipid profiles had an average sensitivity of 94.1% and specificity of 97.4%. The positive and negative mode lipid profiles provided complementary information. Principal component–linear discriminant analysis of the combined positive and negative mode lipid profiles, via data fusion, resulted in approximately the same average sensitivity (94.7%) and specificity (97.6%) of the positive and negative modes when used individually. However, they complemented each other by improving the sensitivity and specificity of all classes (grey matter, white matter, and glioma) beyond 90% when used in combination. Further principal component analysis using the fused data resulted in the subgrouping of glioma into two groups associated with grey and white matter, respectively, a separation not apparent in the principal component analysis scores plots of the separate positive and negative mode data. The interrelationship of tumor cell percentage and the lipid profiles is discussed, and how such a measure could be used to measure residual tumor at surgical margins. PMID:27658243

  13. High-frequency normal-mode statistics in shallow water: the combined effect of random surface and internal waves.

    PubMed

    Raghukumar, Kaustubha; Colosi, John A

    2015-05-01

    In an earlier article, the statistical properties of mode propagation were studied at a frequency of 1 kHz in a shallow water environment with random sound-speed perturbations from linear internal waves, using a hybrid transport theory and Monte Carlo numerical simulations. Here, the analysis is extended to include the effects of random linear surface waves, in isolation and in combination with internal waves. Mode coupling rates for both surface and internal waves are found to be significant, but strongly dependent on mode number. Mode phase randomization by surface waves is found to be dominated by coupling effects, and therefore a full transport theory treatment of the range evolution of the cross mode coherence matrix is needed. The second-moment of mode amplitudes is calculated using transport theory, thereby providing the mean intensity while the fourth-moment is calculated using Monte Carlo simulations, which provides the scintillation index. The transport theory results for second-moment statistics are shown to closely reproduce Monte Carlo simulations. Both surface waves and internal waves strongly influence the acoustic field fluctuations.

  14. Active control of Type-I Edge-Localized Modes on JET

    SciTech Connect

    Liang, Y.; Koslowski, R.; Thomas, P.; Nardon, E.; Jachmich, S.; Baranov, Y.; Beurskens, M.; Bigi, M.; Crombe, K.; de la Luna, E.; De Vries, P.; Eich, T.; Esser, H. G.; Fundamenski, W.; Hawkes, N. C.; Jakubowski, M.; Kiptily, V.; Moreira, L.; Rachlew, Elisabeth G; Schmitz, O.; Zimmermann, O.

    2007-11-01

    The operational domain for active control of type-I edge localized modes (ELMs) with an n = 1 external magnetic perturbation field induced by the ex-vessel error field correction coils on JET has been developed towards more ITER-relevant regimes with high plasma triangularity, up to 0.45, high normalized beta, up to 3.0, plasma current up to 2.0 MA and q95 varied between 3.0 and 4.8. The results of ELM mitigation in high triangularity plasmas show that the frequency of type-I ELMs increased by a factor of 4 during the application of the n = 1 fields, while the energy loss per ELM, W/W, decreased from 6% to below the noise level of the diamagnetic measurement (<2%). No reduction of confinement quality (H98Y) during the ELM mitigation phase has been observed. The minimum n = 1 perturbation field amplitude above which the ELMs were mitigated increased with a lower q95 but always remained below the n = 1 locked mode threshold. The first results of ELM mitigation with n = 2 magnetic perturbations on JET demonstrate that the frequency of ELMs increased from 10 to 35 Hz and a wide operational window of q95 from 4.5 to 3.1 has been found.

  15. Three key regimes of single pulse generation per round trip of all-normal-dispersion fiber lasers mode-locked with nonlinear polarization rotation.

    PubMed

    Smirnov, Sergey; Kobtsev, Sergey; Kukarin, Sergey; Ivanenko, Aleksey

    2012-11-19

    We show experimentally and numerically new transient lasing regime between stable single-pulse generation and noise-like generation. We characterize qualitatively all three regimes of single pulse generation per round-trip of all-normal-dispersion fiber lasers mode-locked due to effect of nonlinear polarization evolution. We study spectral and temporal features of pulses produced in all three regimes as well as compressibility of such pulses. Simple criteria are proposed to identify lasing regime in experiment. PMID:23187603

  16. Three key regimes of single pulse generation per round trip of all-normal-dispersion fiber lasers mode-locked with nonlinear polarization rotation.

    PubMed

    Smirnov, Sergey; Kobtsev, Sergey; Kukarin, Sergey; Ivanenko, Aleksey

    2012-11-19

    We show experimentally and numerically new transient lasing regime between stable single-pulse generation and noise-like generation. We characterize qualitatively all three regimes of single pulse generation per round-trip of all-normal-dispersion fiber lasers mode-locked due to effect of nonlinear polarization evolution. We study spectral and temporal features of pulses produced in all three regimes as well as compressibility of such pulses. Simple criteria are proposed to identify lasing regime in experiment.

  17. High energy pulses generation with giant spectrum bandwidth and submegahertz repetition rate from a passively mode-locked Yb-doped fiber laser in all normal dispersion cavity

    NASA Astrophysics Data System (ADS)

    Lin, J.-H.; Wang, D.; Lin, K.-H.

    2011-01-01

    Robust passively mode-locked pulse generation with low pulse repetition rate and giant spectrum bandwidth in an all-fiber, all-normal-dispersion ytterbium-doped fiber laser has been experimentally demonstrated using nonlinear polarization evolution technique. The highest pulse energy over 20 nJ with spectrum bandwidth over 50 nm can be experimentally obtained at 175 mW pump power. The mode-locked pulses reveal broadened 3-dB pulsewidth about several nanosecond and widened pedestal in time trace that is resulted from enormous dispersion in laser cavity and gain dynamics. At certain mode-locking state, a spectrum gap around 1056 nm are observed between the three and four energy levels of Yb-doped fiber laser. By properly rotating the polarization controller, the gap can be eliminated due to four-wave mixing to produce more flattened spectrum output.

  18. Cardiorespiratory performance and physical activity in normal weight and overweight Finnish adolescents from 2003 to 2010.

    PubMed

    Palomäki, Sanna; Heikinaro-Johansson, Pilvikki; Huotari, Pertti

    2015-01-01

    We investigated changes in cardiorespiratory performance, BMI and leisure-time physical activity among Finnish adolescents from 2003 to 2010. In addition, we compared cardiorespiratory performance levels between normal weight and overweight adolescents, grouped according to their physical activity. Participants were a national representative samples of 15-16-year-old adolescents in their final (ninth) year of comprehensive school in 2003 (n = 2258) and in 2010 (n = 1301). They performed an endurance shuttle run test and reported their height and weight and leisure time physical activity on a questionnaire. Results showed no significant secular changes in cardiorespiratory performance from 2003 to 2010. The mean BMI increased in boys. Leisure-time physical activity increased among normal weight girls. Adolescents of normal weight had better cardiorespiratory performance than those classified as overweight at both assessment points. BMI-adjusted physical activity was a significant determinant for cardiorespiratory performance among overweight adolescents, and very active overweight adolescents had similar cardiorespiratory performance levels as moderately active adolescents of normal weight. The results of the present study support the idea that the physical activity has the great importance for the cardiorespiratory performance in adolescents. Overweight adolescents, in particular, benefit from higher levels of physical activity.

  19. Computation of synthetic seismograms in a 3 dimensional Earth and inversion of eigenfrequency and Q quality factor datasets of normal modes

    NASA Astrophysics Data System (ADS)

    Roch, Julien; Clevede, Eric; Roult, Genevieve

    2010-05-01

    The 26 December 2004 Sumatra-Andaman event is the third biggest earthquake that has never been recorded but the first recorded with high quality broad-band seismometers. Such an earthquake offered a good opportunity for studying the normal modes of the Earth and particularly the gravest ones (frequency lower than 1 mHz) which provide important information on deep Earth. The splitting of some modes has been carefully analyzed. The eigenfrequencies and the Q quality factors of particular singlets have been retrieved with an unprecedented precision. In some cases, the eigenfrequencies of some singlets exhibit a clear shift when compared to the theoretical eigenfrequencies. Some core modes such as the 3S2 mode present an anomalous splitting, that is to say, a splitting width much larger than the expected one. Such anomalous splitting is presently admitted to be due to the existence of lateral heterogeneities in the inner core. We need an accurate model of the whole Earth and a method to compute synthetic seismograms in order to compare synthetic and observed data and to explain the behavior of such modes. Synthetic seismograms are computed by normal modes summation using a perturbative method developed up to second order in amplitude and up to third order in frequency (HOPT method). The last step consists in inverting both eigenfrequency and Q quality factor datasets in order to better constrain the deep Earth structure and especially the inner core. In order to find models of acceptable data fit in a multidimensional parameter space, we use the neighborhood algorithm method which is a derivative-free search method. It is particularly well adapted in our case (non linear problem) and is easy to tune with only 2 parameters. Our purpose is to find an ensemble of models that fit the data rather than a unique model.

  20. Surface enhanced Raman scattering, natural bond orbitals and Mulliken atomic charge distribution in the normal modes of diethyldithiocarbamate cadmium (II) complex, [Cd(DDTC)₂].

    PubMed

    Soto, C A Téllez; Costa, A C; Versiane, O; Lemma, T; Machado, N C F; Mondragón, M A; Martin, A A

    2015-07-01

    Theoretical and experimental bands have been assigned to the Fourier Transform Infrared (FT-IR) and FT-Raman spectra of the bis(diethyldithiocarbamate)Cd(II) complex, abbreviated as ([Cd(DDTC)2]). The calculations and spectral interpretation have been based on the DFT/B3LYP method, infrared and Raman second derivative spectra, and band deconvolution analysis to assist in the assignment of observed fundamentals. This study validated the unusual pseudo tetrahedral molecular structure formed around the Cd(II) cation. Surface-enhanced Raman scattering (SERS) was used to determine the interactions of the normal-modes of the diethyldithiocarbamate cadmium (II) complex on nano-structured silver surfaces. Natural bond orbital (NBO) analysis was also carried out to study the Cd(II) hybridization causing the pseudo tetrahedral geometry of the framework of the [Cd(DDTC)2] complex, and to confirm the charge transfer mechanisms through second order perturbation theory analysis of the Fox Matrix. In order to find out the electronic dispersion of the Mulliken atomic charges (MAC) in the normal modes, we calculated the MAC for each normal mode and correlated these values with the SERS effect. Experimental UV-Vis spectra were obtained and charge transfer bands were assigned. Good agreement between the calculated and experimental values for the vibrational and UV-Vis spectra was obtained.

  1. Detection of aryl hydrocarbon hydroxylase activity in normal and neoplastic human breast epithelium

    SciTech Connect

    Greiner, J.W.; Malan-Shibley, L.B.; Janss, D.H.

    1980-01-28

    Studies were conducted to determine whether normal and/or neoplastic (MCF-7) human breast epithelial cells contain the microsomal aryl hydrocarbon hydroxylase (AHH) which catalyses the conversion of polycyclic aromatic hydrocarbons (PAH) to carcinogenic intermediates. Low constitutive levels of AHH activity were found in homogenates of both normal human breast epithelial and MCF-7 cells. The addition of 7,12-dimethylbenz(a)anthracene (DMBA) to the culture medium of either cell type significantly increased AHH activity. Peak induction of hydroxylase activity occurred following the in vitro addition of 10 ..mu..M DMBA. A time course of DMBA-induced AHH activity in both normal human breast epithelium and MCF-7 cells revealed maximal induction 16 hr after 10 ..mu..M DMBA was added to the culture medium. Benzo(a)pyrene (BP), 3-methylcholanthrene (MCA) and benz(a)anthracene (BA) also induced AHH activity in normal and MCF-7 cells. For example, the addition of 10 ..mu..M BP to the culture medium of either normal human breast epithelial or MCF-7 cells for 16 hr increased AHH activity 13.8 and 65.3-fold, respectively. For all PAH, the magnitude of AHH induction was substantially greater in MCF-7 than normal breast epithelial cells. Finally, ..cap alpha..-naphthoflavone inhibited BA-induced AHH activity in MCF-7 cells. The study demonstrates the presence of a PAH-inducible AHH enzyme(s) in normal human breast epithelial cells grown in primary culture and in the human breast tumor cell line, MCF-7.

  2. MID-INFRARED SPECTRAL INDICATORS OF STAR FORMATION AND ACTIVE GALACTIC NUCLEUS ACTIVITY IN NORMAL GALAXIES

    SciTech Connect

    Treyer, Marie; Martin, Christopher D.; Wyder, Ted; Schiminovich, David; O'Dowd, Matt; Johnson, Benjamin D.; Charlot, Stephane; Heckman, Timothy; Martins, Lucimara; Seibert, Mark; Van der Hulst, J. M.

    2010-08-20

    We investigate the use of mid-infrared (MIR) polycyclic aromatic hydrocarbon (PAH) bands, the continuum, and emission lines as probes of star formation (SF) and active galactic nucleus (AGN) activity in a sample of 100 'normal' and local (z {approx} 0.1) emission-line galaxies. The MIR spectra were obtained with the Spitzer Space Telescope Infrared Spectrograph as part of the Spitzer-SDSS-GALEX Spectroscopic Survey, which includes multi-wavelength photometry from the ultraviolet to the far-infrared and optical spectroscopy. The continuum and features were extracted using PAHFIT, a decomposition code which we find to yield PAH equivalent widths (EWs) up to {approx}30 times larger than the commonly used spline methods. Despite the lack of extreme objects in our sample (such as strong AGNs, low-metallicity galaxies, or ULIRGs), we find significant variations in PAH, continuum, and emission-line properties, and systematic trends between these MIR properties and optically derived physical properties, such as age, metallicity, and radiation field hardness. We revisit the diagnostic diagram relating PAH EWs and [Ne II]12.8 {mu}m/[O IV]25.9 {mu}m line ratios and find it to be in much better agreement with the standard optical SF/AGN classification than when spline decompositions are used, while also potentially revealing obscured AGNs. The luminosity of individual PAH components, of the continuum, and, with poorer statistics, of the neon emission lines and molecular hydrogen lines are found to be tightly correlated to the total infrared (TIR) luminosity, making individual MIR components good gauges of the total dust emission in SF galaxies. Like the TIR luminosity, these individual components can be used to estimate dust attenuation in the UV and in H{alpha} lines based on energy balance arguments. We also propose average scaling relations between these components and dust-corrected, H{alpha}-derived SF rates.

  3. 29 CFR 778.332 - Awards for activities not normally part of employee's job.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Awards for activities not normally part of employee's job. 778.332 Section 778.332 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION... of employee's job. (a) Where the prize is awarded for activities outside the customary working...

  4. 29 CFR 778.332 - Awards for activities not normally part of employee's job.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Awards for activities not normally part of employee's job. 778.332 Section 778.332 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION... of employee's job. (a) Where the prize is awarded for activities outside the customary working...

  5. 29 CFR 778.332 - Awards for activities not normally part of employee's job.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Awards for activities not normally part of employee's job. 778.332 Section 778.332 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION... of employee's job. (a) Where the prize is awarded for activities outside the customary working...

  6. Physical activity patterns and estimated daily energy expenditures in normal and overweight tunisian schoolchildren

    PubMed Central

    Zarrouk, Fayçal; Bouhlel, Ezdine; Feki, Youssef; Amri, Mohamed; Shephard, Roy J.

    2009-01-01

    Our aim was to test the normality of physical activity patterns and energy expenditures in normal weight and overweight primary school students. Heart rate estimates of total daily energy expenditure (TEE), active energy expenditure (AEE), and activity patterns were made over 3 consecutive school days in healthy middle-class Tunisian children (46 boys, 44 girls, median age (25th-75th) percentile, 9.2 (8.8-9.9) years. Our cross-section included 52 students with a normal body mass index (BMI) and 38 who exceeded age-specific BMI limits. TEE, AEE and overall physical activity level (PAL) were not different between overweight children and those with a normal BMI [median values (25th-75th) 9.20 (8.20-9.84) vs. 8.88 (7.42-9.76) MJ/d; 3.56 (2.59-4.22) vs. 3.85 (2.77-4.78) MJ/d and 1.74 (1.54-2.04) vs. 1.89 (1.66-2.15) respectively]. Physical activity intensities (PAI) were expressed as percentages of the individual’s heart rate reserve (%HRR). The median PAI for the entire day (PAI24) and for the waking part of day (PAIw) were lower in overweight than in normal weight individuals [16.3 (14.2-18.9) vs. 20.6 (17.9-22.3) %HRR, p < 0.001) and 24.8 (21.6-28.9) vs.26.2 (24.5-30.8) %HRR, p < 0.01], respectively. Overweight children allocated more of their day to sedentary pursuits [385 (336-468) vs 297 (235-468) min/d, p < 0.001], and less time to moderate physical activity [381(321-457) vs. 460 (380-534) min/d, p < 0.01]. Nevertheless, because of the greater energy cost of a given task, total and active daily energy expenditure did not differ from those with a normal BMI. Key points The physical activity intensity for the entire day (PAI24) and for the waking part of day (PAIw) were lower in overweight than in normal weight individuals. However, because the energy cost of activity is greater in those who are overweight, they do not differ in total energy expenditure or in active energy expenditure. Normal children spend more time in moderate activity and less time in

  7. All fiber actively mode-locked fiber laser emitting cylindrical vector beam

    NASA Astrophysics Data System (ADS)

    Zhou, Yong; Wang, Anting; Gu, Chun; Xu, Lixin; Zhan, Qiwen

    2015-08-01

    We demonstrated an all fiber actively mode-locked laser emitting cylindrical vector beam. A few-mode fiber Bragg grating is adopted to achieve mode selecting and spectrum filtering. An offset splicing of single-mode fiber with fourmode fiber is utilized as a mode coupler in the laser cavity. A LiNbO3 Mach-Zehnder modulator is used to achieve active mode locking in the laser. The laser operates at 1547nm with 30 dB spectrum width of 0.3nm. The emitted modelocked pulses have a duration of 1ns and repetition of 12.06MHz. Both radially and azimuthally polarized beams have been obtained with very good modal symmetry by adjusting the polarization in the laser cavity.

  8. Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique

    SciTech Connect

    Fry-Petit, A. M. E-mail: afry@fullerton.edu; Sheckelton, J. P.; McQueen, T. M. E-mail: afry@fullerton.edu; Rebola, A. F.; Fennie, C. J.; Mourigal, M.; Valentine, M.; Drichko, N.

    2015-09-28

    For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn{sub 2}Mo{sub 3}O{sub 8}, this approach allows direct assignment of the constrained rotational mode of Mo{sub 3}O{sub 13} clusters and internal modes of MoO{sub 6} polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems.

  9. Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique.

    PubMed

    Fry-Petit, A M; Rebola, A F; Mourigal, M; Valentine, M; Drichko, N; Sheckelton, J P; Fennie, C J; McQueen, T M

    2015-09-28

    For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn2Mo3O8, this approach allows direct assignment of the constrained rotational mode of Mo3O13 clusters and internal modes of MoO6 polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems.

  10. Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique

    NASA Astrophysics Data System (ADS)

    Fry-Petit, A. M.; Rebola, A. F.; Mourigal, M.; Valentine, M.; Drichko, N.; Sheckelton, J. P.; Fennie, C. J.; McQueen, T. M.

    2015-09-01

    For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn2Mo3O8, this approach allows direct assignment of the constrained rotational mode of Mo3O13 clusters and internal modes of MoO6 polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems.

  11. Analysis of the characteristics of solar oscillation modes in active regions

    NASA Astrophysics Data System (ADS)

    Rabello-Soares, M. Cristina; Bogart, Richard S.; Basu, Sarbani

    2008-10-01

    We analyze the characteristics of high-degree solar acoustic modes in the vicinity of magnetic active regions and compare with those of magnetically quiet regions at the same latitude and at nearly the same time. We applied ring-diagram analysis to GONG+ and MDI data, using the 13-parameter mode-fitting model of Basu & Antia [1]. We explore the correlations of variations in mode frequencies, amplitudes, widths, and asymmetries with the total magnetic flux of the analyzed regions.

  12. External kink modes as a model for MHD activity associated with ELMs

    SciTech Connect

    Manickam, J.

    1992-01-01

    Tokamak plasmas in the high confinement mode of operation are known to exhibit edge localized activity referred to as ELMs. A model is proposed for the underlying cause in terms of the external kink mode. The build up of the current density near the plasma edge is shown to decrease the shear in the safety-factor, q, profile and lead to destabilization of the kink mode. The role of the plasma geometry and equilibrium profiles is discussed.

  13. The Properties of Large Amplitude Whistler Mode Waves in the Magnetosphere: Propagation and Relationship with Geomagnetic Activity

    NASA Technical Reports Server (NTRS)

    Wilson, L. B., III; Cattell, C. A.; Kellogg, P. J.; Wygant, J. R.; Goetz, K.; Breneman, A.; Kersten, K.

    2011-01-01

    Wepresent resultsof a studyof the characteristicsof very large amplitude whistler mode waves inside the terrestrial magnetosphere at radial distances of less than 15 RE using waveform capture data from the Wind spacecraft. We observed 247 whistler mode waves with at least one electric field component (105/247 had !80 mV/m peak!to!peak amplitudes) and 66 whistler mode waves with at least one search coil magnetic field component (38/66 had !0.8 nT peak!to!peak amplitudes). Wave vectors determined from events with three magnetic field components indicate that 30/46 propagate within 20 of the ambient magnetic field, though some are more oblique (up to "50 ). No relationship was observed between wave normal angle and GSM latitude. 162/247 of the large amplitude whistler mode waves were observed during magnetically active periods (AE > 200 nT). 217 out of 247 total whistler mode waves examined were observed inside the radiation belts. We present a waveform capture with the largest whistler wave magnetic field amplitude (^8 nT peak!to!peak) ever reported in the radiation belts. The estimated Poynting flux magnitude associated with this wave is ^300 mW/m2, roughly four orders of magnitude above estimates from previous satellite measurements. Such large Poynting flux values are consistent with rapid energization of electrons.

  14. Multi-scaled normal mode analysis method for dynamics simulation of protein-membrane complexes: A case study of potassium channel gating motion correlations

    SciTech Connect

    Wu, Xiaokun; Han, Min; Ming, Dengming

    2015-10-07

    Membrane proteins play critically important roles in many cellular activities such as ions and small molecule transportation, signal recognition, and transduction. In order to fulfill their functions, these proteins must be placed in different membrane environments and a variety of protein-lipid interactions may affect the behavior of these proteins. One of the key effects of protein-lipid interactions is their ability to change the dynamics status of membrane proteins, thus adjusting their functions. Here, we present a multi-scaled normal mode analysis (mNMA) method to study the dynamics perturbation to the membrane proteins imposed by lipid bi-layer membrane fluctuations. In mNMA, channel proteins are simulated at all-atom level while the membrane is described with a coarse-grained model. mNMA calculations clearly show that channel gating motion can tightly couple with a variety of membrane deformations, including bending and twisting. We then examined bi-channel systems where two channels were separated with different distances. From mNMA calculations, we observed both positive and negative gating correlations between two neighboring channels, and the correlation has a maximum as the channel center-to-center distance is close to 2.5 times of their diameter. This distance is larger than recently found maximum attraction distance between two proteins embedded in membrane which is 1.5 times of the protein size, indicating that membrane fluctuation might impose collective motions among proteins within a larger area. The hybrid resolution feature in mNMA provides atomic dynamics information for key components in the system without costing much computer resource. We expect it to be a conventional simulation tool for ordinary laboratories to study the dynamics of very complicated biological assemblies. The source code is available upon request to the authors.

  15. Multi-scaled normal mode analysis method for dynamics simulation of protein-membrane complexes: A case study of potassium channel gating motion correlations

    NASA Astrophysics Data System (ADS)

    Wu, Xiaokun; Han, Min; Ming, Dengming

    2015-10-01

    Membrane proteins play critically important roles in many cellular activities such as ions and small molecule transportation, signal recognition, and transduction. In order to fulfill their functions, these proteins must be placed in different membrane environments and a variety of protein-lipid interactions may affect the behavior of these proteins. One of the key effects of protein-lipid interactions is their ability to change the dynamics status of membrane proteins, thus adjusting their functions. Here, we present a multi-scaled normal mode analysis (mNMA) method to study the dynamics perturbation to the membrane proteins imposed by lipid bi-layer membrane fluctuations. In mNMA, channel proteins are simulated at all-atom level while the membrane is described with a coarse-grained model. mNMA calculations clearly show that channel gating motion can tightly couple with a variety of membrane deformations, including bending and twisting. We then examined bi-channel systems where two channels were separated with different distances. From mNMA calculations, we observed both positive and negative gating correlations between two neighboring channels, and the correlation has a maximum as the channel center-to-center distance is close to 2.5 times of their diameter. This distance is larger than recently found maximum attraction distance between two proteins embedded in membrane which is 1.5 times of the protein size, indicating that membrane fluctuation might impose collective motions among proteins within a larger area. The hybrid resolution feature in mNMA provides atomic dynamics information for key components in the system without costing much computer resource. We expect it to be a conventional simulation tool for ordinary laboratories to study the dynamics of very complicated biological assemblies. The source code is available upon request to the authors.

  16. Multi-scaled normal mode analysis method for dynamics simulation of protein-membrane complexes: A case study of potassium channel gating motion correlations.

    PubMed

    Wu, Xiaokun; Han, Min; Ming, Dengming

    2015-10-01

    Membrane proteins play critically important roles in many cellular activities such as ions and small molecule transportation, signal recognition, and transduction. In order to fulfill their functions, these proteins must be placed in different membrane environments and a variety of protein-lipid interactions may affect the behavior of these proteins. One of the key effects of protein-lipid interactions is their ability to change the dynamics status of membrane proteins, thus adjusting their functions. Here, we present a multi-scaled normal mode analysis (mNMA) method to study the dynamics perturbation to the membrane proteins imposed by lipid bi-layer membrane fluctuations. In mNMA, channel proteins are simulated at all-atom level while the membrane is described with a coarse-grained model. mNMA calculations clearly show that channel gating motion can tightly couple with a variety of membrane deformations, including bending and twisting. We then examined bi-channel systems where two channels were separated with different distances. From mNMA calculations, we observed both positive and negative gating correlations between two neighboring channels, and the correlation has a maximum as the channel center-to-center distance is close to 2.5 times of their diameter. This distance is larger than recently found maximum attraction distance between two proteins embedded in membrane which is 1.5 times of the protein size, indicating that membrane fluctuation might impose collective motions among proteins within a larger area. The hybrid resolution feature in mNMA provides atomic dynamics information for key components in the system without costing much computer resource. We expect it to be a conventional simulation tool for ordinary laboratories to study the dynamics of very complicated biological assemblies. The source code is available upon request to the authors. PMID:26450298

  17. Multi-scaled normal mode analysis method for dynamics simulation of protein-membrane complexes: A case study of potassium channel gating motion correlations.

    PubMed

    Wu, Xiaokun; Han, Min; Ming, Dengming

    2015-10-01

    Membrane proteins play critically important roles in many cellular activities such as ions and small molecule transportation, signal recognition, and transduction. In order to fulfill their functions, these proteins must be placed in different membrane environments and a variety of protein-lipid interactions may affect the behavior of these proteins. One of the key effects of protein-lipid interactions is their ability to change the dynamics status of membrane proteins, thus adjusting their functions. Here, we present a multi-scaled normal mode analysis (mNMA) method to study the dynamics perturbation to the membrane proteins imposed by lipid bi-layer membrane fluctuations. In mNMA, channel proteins are simulated at all-atom level while the membrane is described with a coarse-grained model. mNMA calculations clearly show that channel gating motion can tightly couple with a variety of membrane deformations, including bending and twisting. We then examined bi-channel systems where two channels were separated with different distances. From mNMA calculations, we observed both positive and negative gating correlations between two neighboring channels, and the correlation has a maximum as the channel center-to-center distance is close to 2.5 times of their diameter. This distance is larger than recently found maximum attraction distance between two proteins embedded in membrane which is 1.5 times of the protein size, indicating that membrane fluctuation might impose collective motions among proteins within a larger area. The hybrid resolution feature in mNMA provides atomic dynamics information for key components in the system without costing much computer resource. We expect it to be a conventional simulation tool for ordinary laboratories to study the dynamics of very complicated biological assemblies. The source code is available upon request to the authors.

  18. Antioxidant supplementation normalizes elevated protein kinase C activity in the proximal tubules of old rats.

    PubMed

    Asghar, Mohammad; Lokhandwala, Mustafa F

    2004-03-01

    Aging is associated with increase in oxidative stress. Earlier, we have shown that higher basal protein kinase C (PKC) activity in the proximal tubules (PTs) of old rats contributes to the hyperphosphorylation of Na,K-ATPase and subsequent decrease in basal Na,K-ATPase activity, resulting in diminished natriuretic response to dopamine in these animals. We hypothesized that the increase in PKC activity in PTs of old rats is caused by increased oxidative stress and that antioxidants administration should reduce/normalize the elevated PKC activity in the renal PTs of old rats. We studied the effect of two antioxidants, namely, alpha-lipoic acid (LA) and tempol, on oxidants level and PKC activity in the PTs of adult (6-month) and old (24-month) Fischer 344 rats. We found that the accumulation of fluorescent dichlorofluorescein (DCF), an indicator of oxidant production, was higher in the PTs of old compared to adult rats. Dietary supplementation with LA for 2 weeks normalized the increased DCF level in old rats. Carboxymethylysine and malondialdehyde, markers of oxidative damage, were elevated in the PTs of old rats, which were normalized to the level of adult rats when tempol was provided in drinking water for 3 weeks. Both LA and tempol treatment also normalized the higher basal PKC activity in the PTs of old rats to the level seen in adult rats. These results suggest that increase in oxidative stress causes an increase in PKC activity, and that antioxidants, while reducing oxidative stress, also normalize PKC activity in the PTs of old rats.

  19. Study of different HILIC, mixed-mode, and other aqueous normal-phase approaches for the liquid chromatography/mass spectrometry-based determination of challenging polar pesticides.

    PubMed

    Vass, Andrea; Robles-Molina, José; Pérez-Ortega, Patricia; Gilbert-López, Bienvenida; Dernovics, Mihaly; Molina-Díaz, Antonio; García-Reyes, Juan F

    2016-07-01

    The aim of the study was to evaluate the performance of different chromatographic approaches for the liquid chromatography/mass spectrometry (LC-MS(/MS)) determination of 24 highly polar pesticides. The studied compounds, which are in most cases unsuitable for conventional LC-MS(/MS) multiresidue methods were tested with nine different chromatographic conditions, including two different hydrophilic interaction liquid chromatography (HILIC) columns, two zwitterionic-type mixed-mode columns, three normal-phase columns operated in HILIC-mode (bare silica and two silica-based chemically bonded columns (cyano and amino)), and two standard reversed-phase C18 columns. Different sets of chromatographic parameters in positive (for 17 analytes) and negative ionization modes (for nine analytes) were examined. In order to compare the different approaches, a semi-quantitative classification was proposed, calculated as the percentage of an empirical performance value, which consisted of three main features: (i) capacity factor (k) to characterize analyte separation from the void, (ii) relative response factor, and (iii) peak shape based on analytes' peak width. While no single method was able to provide appropriate detection of all the 24 studied species in a single run, the best suited approach for the compounds ionized in positive mode was based on a UHPLC HILIC column with 1.8 μm particle size, providing appropriate results for 22 out of the 24 species tested. In contrast, the detection of glyphosate and aminomethylphosphonic acid could only be achieved with a zwitterionic-type mixed-mode column, which proved to be suitable only for the pesticides detected in negative ion mode. Finally, the selected approach (UHPLC HILIC) was found to be useful for the determination of multiple pesticides in oranges using HILIC-ESI-MS/MS, with limits of quantitation in the low microgram per kilogram in most cases. Graphical Abstract HILIC improves separation of multiclass polar pesticides.

  20. Study of different HILIC, mixed-mode, and other aqueous normal-phase approaches for the liquid chromatography/mass spectrometry-based determination of challenging polar pesticides.

    PubMed

    Vass, Andrea; Robles-Molina, José; Pérez-Ortega, Patricia; Gilbert-López, Bienvenida; Dernovics, Mihaly; Molina-Díaz, Antonio; García-Reyes, Juan F

    2016-07-01

    The aim of the study was to evaluate the performance of different chromatographic approaches for the liquid chromatography/mass spectrometry (LC-MS(/MS)) determination of 24 highly polar pesticides. The studied compounds, which are in most cases unsuitable for conventional LC-MS(/MS) multiresidue methods were tested with nine different chromatographic conditions, including two different hydrophilic interaction liquid chromatography (HILIC) columns, two zwitterionic-type mixed-mode columns, three normal-phase columns operated in HILIC-mode (bare silica and two silica-based chemically bonded columns (cyano and amino)), and two standard reversed-phase C18 columns. Different sets of chromatographic parameters in positive (for 17 analytes) and negative ionization modes (for nine analytes) were examined. In order to compare the different approaches, a semi-quantitative classification was proposed, calculated as the percentage of an empirical performance value, which consisted of three main features: (i) capacity factor (k) to characterize analyte separation from the void, (ii) relative response factor, and (iii) peak shape based on analytes' peak width. While no single method was able to provide appropriate detection of all the 24 studied species in a single run, the best suited approach for the compounds ionized in positive mode was based on a UHPLC HILIC column with 1.8 μm particle size, providing appropriate results for 22 out of the 24 species tested. In contrast, the detection of glyphosate and aminomethylphosphonic acid could only be achieved with a zwitterionic-type mixed-mode column, which proved to be suitable only for the pesticides detected in negative ion mode. Finally, the selected approach (UHPLC HILIC) was found to be useful for the determination of multiple pesticides in oranges using HILIC-ESI-MS/MS, with limits of quantitation in the low microgram per kilogram in most cases. Graphical Abstract HILIC improves separation of multiclass polar pesticides

  1. Immunosuppressive activity of human amniotic fluid of normal and abnormal pregnancies.

    PubMed

    Shohat, B; Faktor, J M

    1988-01-01

    Twenty specimens of amniotic fluid (AF) obtained between week 16 and 18 of gestation from normal pregnant women and six specimens from pregnant women in which trisomia of chromosome 21 was found were tested for immunosuppressive activity. Incubation of normal human donor lymphocytes with 0.2-1 mL of AF from normal pregnant women for one hour at 37 degrees C was sufficient for induction of significant inhibition of the ability of these cells to induce a local xenogeneic graft-versus-host reaction (GVHR) as well as inhibition of E and E-active rosette formation, the GVHR being the most sensitive test. On the other hand, amniotic fluid obtained from the six pregnant women in which trisomia of chromosome 21 was found showed no inhibitory activity in either the E or E-active rosette formation, nor in the local xenogeneic graft-versus-host reaction. AF from all the women tested was found to have no effect on phenotype expression of the lymphocytes, as tested by the monoclonal antibodies OKT4+ and OKT8+, nor on B-lymphocytes, as tested by surface immunoglobulins. No correlation was found between the alpha-fetoprotein levels in the sera of those women and the immunosuppressive activity. These findings indicate that genetic defects of the conceptus are not limited to the embryo but may affect the composition of immunosuppressive components present in normal amniotic fluid.

  2. Loss of p53 induces epidermal growth factor receptor promoter activity in normal human keratinocytes

    PubMed Central

    Bheda, A; Creek, KE; Pirisi, L

    2008-01-01

    Overexpression of the epidermal growth factor receptor (EGFR) in human papillomavirus type 16-immortalized human keratinocytes (HKc) is caused by the viral oncoprotein E6, which targets p53 for degradation. We have previously observed that expression of p53 RNAi in normal HKc is associated with an increase in EGFR mRNA and protein. We now report that p53 RNAi induces EGFR promoter activity up to approximately 10-fold in normal HKc, and this effect does not require intact p53 binding sites on the EGFR promoter. Exogenous wild-type p53 inhibits the EGFR promoter at low levels, and activates it at higher concentrations. Yin Yang 1 (YY1), which negatively regulates p53, induces EGFR promoter activity, and this effect is augmented by p53 RNAi. Intact p53 binding sites on the EGFR promoter are not required for activation by YY1. In addition, Sp1 and YY1 synergistically induce the EGFR promoter in normal HKc, indicating that Sp1 may recruit YY1 as a co-activator. Wild-type p53 suppressed Sp1- and YY1-mediated induction of the EGFR promoter. We conclude that acute loss of p53 in normal HKc induces EGFR expression bya mechanism that involves YY1 and Sp1 and does not require p53 binding to the EGFR promoter. PMID:18391986

  3. Wilsonville SRC-I pilot plant: I. Fractionation area corrosion studies; II. Hot vs. normal separation mode of operation

    SciTech Connect

    Lee, J.M.

    1981-04-01

    Extensive corrosion studies in solvent recovery columns have been done with different coals (mainly Kentucky number 9 Lafayette, Dotiki and Fies). Sodium carbonate (0.1 to 1.1% of coal) was added as neutralizer to control corrosion rate. Chloride balance runs were made for isolation of corrosive streams with high chlorine content. A caustic wash program of inlet streams has been developed for selective treatment of corrosive streams as an alternative means for possible replacement of sodium carbonate addition. High chlorine content coals such as Kentucky number 9 Lafayette and Dotiki (0.2 to 0.3%) were very corrosive, compared to low chlorine content coal, Kentucky number 9 Fies (< 0.1%). Sodium carbonate addition (0.6 to 0.7% of coal) reduced corrosion rate from 500 MPY to an insignificant level of less than 5 MPY. Caustic wash of solvents could reduce corrosion rate by 50%, removing most corrosive compounds present in the 440 to 480/sup 0/F boiling fraction. Extensive studies for the hot separator mode of operation have been done as a means of saving substantial energy by elimination of dissolver slurry cooling (0.3 MM Btu/hr) and reheating for solvent recovery (1 MM Btu/h). Impacts of the hot separator mode on plant operability, product quality and Kerr-McGee CSD Unit recovery have been studied. The hot separator mode of operation was carried out by controlling the V103 temperature to 740/sup 0/F. It was observed that preasphaltene contents increased in the SRC products such as V110 L/F SRC and CSD feed; CSD unit recovery was not affected significantly; solvent quality was not affected significantly.

  4. Reduction of timing jitter and intensity noise in normal-dispersion passively mode-locked fiber lasers by narrow band-pass filtering.

    PubMed

    Qin, Peng; Song, Youjian; Kim, Hyoji; Shin, Junho; Kwon, Dohyeon; Hu, Minglie; Wang, Chingyue; Kim, Jungwon

    2014-11-17

    Fiber lasers mode-locked with normal cavity dispersion have recently attracted great attention due to large output pulse energy and femtosecond pulse duration. Here we accurately characterized the timing jitter of normal-dispersion fiber lasers using a balanced cross-correlation method. The timing jitter characterization experiments show that the timing jitter of normal-dispersion mode-locked fiber lasers can be significantly reduced by using narrow band-pass filtering (e.g., 7-nm bandwidth filtering in this work). We further identify that the timing jitter of the fiber laser is confined in a limited range, which is almost independent of cavity dispersion map due to the amplifier-similariton formation by insertion of the narrow bandpass filter. The lowest observed timing jitter reaches 0.57 fs (rms) integrated from 10 kHz to 10 MHz Fourier frequency. The rms relative intensity noise (RIN) is also reduced from 0.37% to 0.02% (integrated from 1 kHz to 5 MHz Fourier frequency) by the insertion of narrow band-pass filter.

  5. Theoretical study of mode evolution in active long tapered multimode fiber.

    PubMed

    Shi, Chen; Wang, Xiaolin; Zhou, Pu; Xu, Xiaojun; Lu, Qisheng

    2016-08-22

    A concise and effective model based on coupled mode theory to describe mode evolution in long tapered active fiber is presented in this manuscript. The mode coupling due to variation of core radius and slight perturbation have been analyzed and local gain with transverse spatial hole burning (TSHB) effect, loss and curvature have been taken into consideration in our model. On the base of this model, the mode evolution behaviors under different factors have been numerically investigated. Our model and results can provide instructive suggestions when designing long tapered fiber based laser and amplifiers. PMID:27557225

  6. Application of normal mode theory to seismic source and structure problems: Seismic investigations of upper mantle lateral heterogeneity. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Okal, E. A.

    1978-01-01

    The theory of the normal modes of the earth is investigated and used to build synthetic seismograms in order to solve source and structural problems. A study is made of the physical properties of spheroidal modes leading to a rational classification. Two problems addressed are the observability of deep isotropic seismic sources and the investigation of the physical properties of the earth in the neighborhood of the Core-Mantle boundary, using SH waves diffracted at the core's surface. Data sets of seismic body and surface waves are used in a search for possible deep lateral heterogeneities in the mantle. In both cases, it is found that seismic data do not require structural differences between oceans and continents to extend deeper than 250 km. In general, differences between oceans and continents are found to be on the same order of magnitude as the intrinsic lateral heterogeneity in the oceanic plate brought about by the aging of the oceanic lithosphere.

  7. Fuzzy-logic-based hybrid locomotion mode classification for an active pelvis orthosis: Preliminary results.

    PubMed

    Yuan, Kebin; Parri, Andrea; Yan, Tingfang; Wang, Long; Munih, Marko; Vitiello, Nicola; Wang, Qining

    2015-01-01

    In this paper, we present a fuzzy-logic-based hybrid locomotion mode classification method for an active pelvis orthosis. Locomotion information measured by the onboard hip joint angle sensors and the pressure insoles is used to classify five locomotion modes, including two static modes (sitting, standing still), and three dynamic modes (level-ground walking, ascending stairs, and descending stairs). The proposed method classifies these two kinds of modes first by monitoring the variation of the relative hip joint angle between the two legs within a specific period. Static states are then classified by the time-based absolute hip joint angle. As for dynamic modes, a fuzzy-logic based method is proposed for the classification. Preliminary experimental results with three able-bodied subjects achieve an off-line classification accuracy higher than 99.49%.

  8. Fuzzy-logic-based hybrid locomotion mode classification for an active pelvis orthosis: Preliminary results.

    PubMed

    Yuan, Kebin; Parri, Andrea; Yan, Tingfang; Wang, Long; Munih, Marko; Vitiello, Nicola; Wang, Qining

    2015-01-01

    In this paper, we present a fuzzy-logic-based hybrid locomotion mode classification method for an active pelvis orthosis. Locomotion information measured by the onboard hip joint angle sensors and the pressure insoles is used to classify five locomotion modes, including two static modes (sitting, standing still), and three dynamic modes (level-ground walking, ascending stairs, and descending stairs). The proposed method classifies these two kinds of modes first by monitoring the variation of the relative hip joint angle between the two legs within a specific period. Static states are then classified by the time-based absolute hip joint angle. As for dynamic modes, a fuzzy-logic based method is proposed for the classification. Preliminary experimental results with three able-bodied subjects achieve an off-line classification accuracy higher than 99.49%. PMID:26737144

  9. Quantification of pulmonary thallium-201 activity after upright exercise in normal persons: importance of peak heart rate and propranolol usage in defining normal values

    SciTech Connect

    Brown, K.A.; Boucher, C.A.; Okada, R.D.; Strauss, H.W.; Pohost, G.M.

    1984-06-01

    Fifty-nine normal patients (34 angiographically normal and 25 clinically normal by Bayesian analysis) underwent thallium-201 imaging after maximal upright exercise. Lung activity was quantitated relative to myocardial activity and a lung/myocardial activity ratio was determined for each patient. Stepwise regression analysis was then used to examine the influence of patient clinical characteristics and exercise variables on the lung/myocardium ratio. Peak heart rate during exercise and propranolol usage both showed significant negative regression coefficients (p less than 0.001). No other patient data showed a significant relation. Using the regression equation and the estimated variance, a 95% confidence level upper limit of normal could be determined for a give peak heart rate and propranolol status. Sixty-one other patients were studied to validate the predicted upper limits of normal based on this model. None of the 27 patients without coronary artery disease had an elevated lung/myocardial ratio, compared with 1 of 8 with 1-vessel disease (difference not significant), 6 of 14 with 2-vessel disease (p less than 0.005), and 6 of 12 with 3-vessel disease (p less than 0.0001). Thus, lung activity on upright exercise thallium-201 studies can be quantitated relative to myocardial activity, and is inversely related to peak heart rate and propranolol use. Use of a regression analysis allows determination of a 95% confidence upper limit of normal to be anticipated in an individual patient.

  10. Ab initio calculation of transition state normal mode properties and rate constants for the H(T)+CH4(CD4) abstraction and exchange reactions

    NASA Astrophysics Data System (ADS)

    Schatz, George C.; Walch, Stephen P.; Wagner, Albert F.

    1980-11-01

    We present ab initio (GVB-POL-CI) calculations for enough of the region about the abstraction and exchange saddle points for H(T)+CH4(CD4) to perform a full normal mode analysis of the transition states. The resulting normal mode frequencies are compared to four other published surfaces: an ab initio UHF-SCF calculation by Carsky and Zahradnik, a semiempirical surface by Raff, and two semiempirical surfaces by Kurylo, Hollinden, and Timmons. Significant quantitative and qualitative differences exist between the POL-CI results and those of the other surfaces. Transition state theory rate constants and vibrationally adiabatic reaction threshold energies were computed for all surfaces and compared to available experimental values. For abstraction, the POL-CI rates are in good agreement with experimental rates and in better agreement than are the rates of any of the other surfaces. For exchange, uncertainties in the experimental values and in the importance of vibrationally nonadiabatic effects cloud the comparison of theory to experiment. Tentative conclusions are that the POL-CI barrier is too low by several kcal. Unless vibrationaly nonadiabatic effects are severe, the POL-CI surface is still in better agreement with experiment than are the other surfaces. The rates for a simple 3-atom transition state theory model (where CH3 is treated as an atom) are compared to the rates for the full 6-atom model. The kinetic energy coupling of reaction coordinate modes to methyl group modes is identified as being of primary importance in determining the accuracy of the 3-atom model for this system. Substantial coupling in abstraction, but not exchange, causes the model to fail for abstraction but succeed for exchange.

  11. Control-Plate Regression (CPR) Normalization for High-Throughput Screens with Many Active Features.

    PubMed

    Murie, C; Barette, C; Lafanechère, L; Nadon, R

    2014-06-01

    Systematic error is present in all high-throughput screens, lowering measurement accuracy. Because screening occurs at the early stages of research projects, measurement inaccuracy leads to following up inactive features and failing to follow up active features. Current normalization methods take advantage of the fact that most primary-screen features (e.g., compounds) within each plate are inactive, which permits robust estimates of row and column systematic-error effects. Screens that contain a majority of potentially active features pose a more difficult challenge because even the most robust normalization methods will remove at least some of the biological signal. Control plates that contain the same feature in all wells can provide a solution to this problem by providing well-by-well estimates of systematic error, which can then be removed from the treatment plates. We introduce the robust control-plate regression (CPR) method, which uses this approach. CPR's performance is compared to a high-performing primary-screen normalization method in four experiments. These data were also perturbed to simulate screens with large numbers of active features to further assess CPR's performance. CPR performs almost as well as the best performing normalization methods with primary screens and outperforms the Z-score and equivalent methods with screens containing a large proportion of active features.

  12. [Adaptation of acrylic resin dentures polymerized using various activation modes].

    PubMed

    Takamata, T; Inoue, Y; Hashimoto, K; Sugitou, S; Arakawa, H; Kurasawa, I

    1989-12-01

    The purpose of this in vitro study was to compare the dimensional accuracy of maxillary dentures made using a conventional heat-activated PMMA resin, a pour resin, a visible light-activated resin, and a microwave-activated acrylic resin. Two simple methods for measuring dimensional accuracy were used: (1) weight of impression material entrapped between the base and master die and (2) measurement of the posterior border gap at five locations. The volume of space between the denture base and the master die was determined by (1) computation and (2) estimation. Statistical analysis (Bartlett, ANOVA and Tukey's Tests) supported the following conclusions: (1) all groups showed a processing contraction, most apparent from buccal flange to buccal flange, (2) the poorest fitting group was processed in a brass flask and a water bath at a temperature which rose from 70 to 100 degrees C, using a heat activated resin (Acron), (3) the visible light activated resin (Triad) produced dentures of intermediate accuracy, as did Acupac 20 when either heat or microwave activated, (4) the two best fitting groups were prepared from a chemically activated resin system using pressure at low heat (PER form), and the resin developed for microwave activation (Acron MC).

  13. Analysis of the visual artifact in range-gated active imaging, especially in burst mode.

    PubMed

    Matwyschuk, Alexis

    2014-09-20

    After the demonstration of the occurrence of visual artifacts with an active imaging system in burst mode in a previous paper, the analysis of this phenomenon was realized. A visual artifact resulting from a remote zone in the scene can appear in the image of the real visualized zone when the duty cycle of laser pulses is close to 50%, as in the burst mode. Therefore, the elements of this remote zone will create confusion in the image, with erroneous estimated distances. These misinterpretations can be very embarrassing to those attempting to determine the distance of a target in the scene. From the modeling realized and validated in the previous paper, the behavior of the visual artifact was analyzed with two types of burst mode used in active imaging, the duration of the laser pulse being identical to the duration of the temporal aperture of the imager. In the first mode, the width of the visualized zone is set, depending on the distance. The second mode increases the width of the visualized zone so that the foreground of the zone is constantly visible. The results showed that the distance of the visual artifacts in variable mode increased much more quickly than the distance in fixed mode. In both modes, the most intense visual artifacts appear when the range of the visualized zone remains within the first kilometer. When this range is very short, the illuminance of the visual artifact in fixed mode is much more intense than the illuminance in variable mode. On the other hand, for long distances, the illuminance of the visual artifact in variable mode is greater than the illuminance in fixed mode, but decreases quickly beyond a certain distance, making it insignificant.

  14. An assessment of surface wave and normal mode spheroidal Q models by forward modeling of Rayleigh waves

    NASA Astrophysics Data System (ADS)

    Rhie, J.; Lekic, V.; Romanowicz, B.

    2006-12-01

    Some large uncertainties still exist in global average attenuation measurements at long periods (150-300 s), limiting their usefulness for constraining the depth dependence of Q in the mantle. A 15-20 % discrepancy between measurements of Rayleigh wave attenuation using traveling and standing waves has been confirmed by many different studies. There is still a debate on which technique is more accurate. Roult and Clevede [2000] argued that surface wave Q measurements involving minor arc arrival of Rayleigh waves (R1) can be biased due to contamination from not fully attenuated high frequency wave fields and difficulties in determining optimal windows. Therefore, using only later arriving surface wavetrains, which are more averaged and highly attenuated at high frequencies, can improve the surface wave measurements and may be able to reconcile the discrepancies. On the other hand, measurements using waves that have propagated longer distances and therefore interacted more with 3D elastic structure may be biased by multiple scattering and focusing effects, in addition to background noise such as the "hum". To investigate these various effects, we compute predicted waveforms of fundamental mode R3 and R4 from observed R1 and R2 for large and shallow earthquakes recorded at global stations by correcting for dispersion and attenuation over the great circle path using radial Q models based on surface wave and mode approaches, and compare these synthetic R3 and R4 with corresponding observations. The synthetics computed using 1D elastic models on a limited dataset indicate that the great circle attenuation predicted for R1/R3 and R2/R4 can be quite different which points to an effect due to scattering. To investigate these effects further, we plan to expand the dataset and compute synthetics using the Coupled Spectral Element Method, a realistic 3D crust and mantle structure. We have confirmed that the earth's background "hum", although persistent, cannot explain the

  15. Normal mode analysis of a rotating group of lashed turbine blades by substructures. [calculations for blades at rest and at operating speed

    NASA Technical Reports Server (NTRS)

    Filstrup, A. W.

    1973-01-01

    A group of 5 lashed identical stream turbine blades is studied through the use of single level substructuring using NASTRAN level 15.1. An altered version, similar to DMAP Program Number 3 of the NASTRAN Newsletter, of Rigid Format 13.0 was used. Steady-state displacements and stresses due to centrifugal loads are obtained both without and with consideration of differential stiffness. The normal mode calculations were performed for blades at rest and at operating speed. Substructuring lowered the computation costs of the analysis by a factor of four.

  16. Simple all-PM-fiber laser system seeded by an all-normal-dispersion oscillator mode-locked with a nonlinear optical loop mirror

    NASA Astrophysics Data System (ADS)

    Szczepanek, Jan; Kardaś, Tomasz; Nejbauer, Michał; Radzewicz, Czesław; Stepanenko, Yuriy

    2016-03-01

    In this paper we report an all-PM-fiber laser amplifier system seeded by an all-normal-dispersion oscillator mode-locked with a Nonlinear Optical Loop Mirror (NOLM). The presented all-normal-dispersion cavity works in a dissipative soliton regime and delivers highly-chirped, high energy pulses above 2.5 nJ with full width at half maximum below 200 fs. The ultrafast oscillator followed by the all-PM-fiber amplifying stage delivered pulses with the energy of 42.5 nJ and time duration below 190 fs. The electrical field of optical pulses from the system was reconstructed using the SPIDER technique. The influence of nonlinear processes on the pulse temporal envelope was investigated.

  17. Quasi normal modes and P-V criticallity for scalar perturbations in a class of dRGT massive gravity around black holes

    NASA Astrophysics Data System (ADS)

    Prasia, P.; Kuriakose, V. C.

    2016-07-01

    We investigate black holes in a class of dRGT massive gravity for their quasi normal modes (QNMs) for neutral and charged ones using Improved Asymptotic Iteration Method and their thermodynamic behavior. The QNMs are studied for different values of the massive parameter m_g for both neutral and charged dRGT black holes under a massless scalar perturbation. As m_g increases, the magnitude of the quasi normal frequencies are found to be increasing. The results are also compared with the Schwarzchild de Sitter case. P-V criticallity of the aforesaid black hoels under massles scalar perturbation in the de Sitter space are also studied in this paper. It is found that the thermodynamic behavior of a neutral black hole shows no physically feasible phase transition while a charged black hole shows a definite phase transition.

  18. Numerical and experimental investigation of dissipative solitons in passively mode-locked fiber lasers with large net-normal-dispersion and high nonlinearity.

    PubMed

    Liu, Xueming

    2009-12-01

    Dissipative soliton evolution in passively mode-locked fiber lasers with large net-normal-dispersion and high nonlinearity is investigated numerically and confirmed experimentally. I have proposed a theoretical model including the nonlinear polarization evolution and spectral filtering effect. This model successfully predicts the pulse behaviors of the proposed laser, such as the multi-soliton evolution, quasi-rectangle-spectrum profile, trapezoid-spectrum profile, and unstable state. Numerical results show that, in contrast to the typical net- or all-normal-dispersion fiber lasers with the slight variation of the pulse breathing, the breathing ratios of the pulse duration and spectral width of our laser are more than three and two during the intra-cavity propagation, respectively. The nonlinear polarization rotation mechanism together with spectral filtering effect plays the key roles on the pulse evolution. The experimental observations confirm the theoretical predictions.

  19. [A new mode of recording retinal activity: multifocal ERG].

    PubMed

    Mack, G; Dollfus, H; Flament, J; Mohand-Said, S; Sahel, J

    1999-03-01

    Global ERG recordings are only modified in conditions with diffuse or extensive retinal involvement. The use, over the last 6 months, of a new functional testing device: VERIS (visual evoked response imaging system) allows accurate detection and quantification of localized retinal function defects. Our preliminary experience shows that a careful preparation of subjects, standardized testing protocols and a good understanding of the device technology, especially software parameters are mandatory. We report our results on a series of 28 normal volunteers, grouped by age and describe the various graphic presentation of data collected. This technology should allow accurate detection and quantification of retinal functional defects in patients with age related macular degeneration as well as evaluation of visual function in retinitis pigmentosa patients before and after photoreceptor transplantation.

  20. Contact system activation in patients with HAE and normal C1 inhibitor function.

    PubMed

    Ghannam, Arije; Defendi, Federica; Charignon, Delphine; Csopaki, Françoise; Favier, Bertrand; Habib, Mohammed; Cichon, Sven; Drouet, Christian

    2013-11-01

    In addition to hereditary angioedema (HAE) with C1 inhibitor (C1INH) deficiency, a type of HAE with dominant inheritance and normal C1INH function (HAE with normal C1INH) has been described. This relates to contact phase activation with exaggerated kinin formation, and mutations in the coagulation factor XII gene have been identified in some affected families, but the cause of the disease has remained elusive in a majority of families. Several triggering factors are responsible for developing kinin forming system, with participation of endothelium and mast cell component. Angioedema conditions meet the accumulation of kinins with failed kinin catabolism. PMID:24176216

  1. Two stage activated sludge plants--influence of different operational modes on sludge bulking and nitrification.

    PubMed

    Wandl, G; Müller-Rechberger, H; Matsché, N; Svardal, K; Winkler, S

    2002-01-01

    Conventional two stage activated sludge plants often lack sufficient nutrient removal performance due to substrate limitation for denitrification in the second stage. For the extension of the Vienna Main WWTP a two stage concept has been developed and tested by means of a pilot plant (scale 1:10.000). The new concept enables the operation of two different modes: In BYPASS-mode a portion of the primary clarifier effluent is fed directly to the second stage; the HYBRID-mode includes the exchange of mixed liquor between the two stages; over the course of the pilot plant investigations it turned out that nutrient removal is strongly increased in comparison to conventional two stage mode, but the two modes of operation lead to different results with regard to the sludge quality and the nitrification performance. BYPASS mode yields a higher SVI in both stages and a lower nitrification performance in comparison to HYBRID mode. This is caused by the negative influence of the primary effluent on the biocoenosis of the second stage. Additionally, the reduced sludge loading of the first stage in this mode results in a higher sludge age which favours the growth of filaments (Microthrix and Nocardia). In HYBRID-mode the higher load of the first stage results in a lower sludge age, fatty components are metabolized and incorporated in the sludge, thus, the growth of filaments is significantly reduced. Additionally, nitrification inhibiting substances are degraded in the first stage, which results in a higher nitrification performance in the second stage.

  2. All-normal dispersion Yb-doped fiber laser mode-locked by Sb2Te3 topological insulator

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Maciej; Boguslawski, Jakub; Stachowiak, Dorota; Tarka, Jan; Zybala, Rafal; Mars, Krzysztof; Mikula, Andrzej; Sobon, Grzegorz J.; Sotor, Jaroslaw Z.; Abramski, Krzysztof M.

    2016-04-01

    In this paper we demonstrate a preliminary work done on employing antimony telluride (Sb2Te3) topological insulator as a saturable absorber for Yb-doped fiber lasers. The material was deposited onto a side-polished fiber by means of a pulsed magnetron sputtering technique. Fabricated absorber was implemented in an all-normal dispersion cavity and allowed for self-starting dissipative soliton generation. The laser emitted stable pulse train at a repetition rate of 17.07 MHz with 4.25 nm broad output spectrum centered around 1039.4 nm. Average output power amounted to 0.54 mW with 32 pJ pulse energy.

  3. Doubly active Q switching and mode locking of an all-fiber laser.

    PubMed

    Cuadrado-Laborde, Christian; Díez, Antonio; Cruz, Jose L; Andrés, Miguel V

    2009-09-15

    Simultaneous and independent active Q switching and active mode locking of an erbium-doped fiber laser is demonstrated using all-fiber modulation techniques. A magnetostrictive rod attached to the output fiber Bragg grating modulates the Q factor of the Fabry-Perot cavity, whereas active mode locking is achieved by amplitude modulation with a Bragg-grating-based acousto-optic device. Fully modulated Q-switched mode-locked trains of optical pulses were obtained for a wide range of pump powers and repetition rates. For a Q-switched repetition rate of 500 Hz and a pump power of 100 mW, the laser generates trains of 12-14 mode-locked pulses of about 1 ns each, within an envelope of 550 ns, an overall energy of 0.65 microJ, and a peak power higher than 250 W for the central pulses of the train.

  4. Normal mode analysis of the spectral density of the Fenna-Matthews-Olson light-harvesting protein: how the protein dissipates the excess energy of excitons.

    PubMed

    Renger, Thomas; Klinger, Alexander; Steinecker, Florian; Schmidt am Busch, Marcel; Numata, Jorge; Müh, Frank

    2012-12-20

    We report a method for the structure-based calculation of the spectral density of the pigment-protein coupling in light-harvesting complexes that combines normal-mode analysis with the charge density coupling (CDC) and transition charge from electrostatic potential (TrEsp) methods for the computation of site energies and excitonic couplings, respectively. The method is applied to the Fenna-Matthews-Olson (FMO) protein in order to investigate the influence of the different parts of the spectral density as well as correlations among these contributions on the energy transfer dynamics and on the temperature-dependent decay of coherences. The fluctuations and correlations in excitonic couplings as well as the correlations between coupling and site energy fluctuations are found to be 1 order of magnitude smaller in amplitude than the site energy fluctuations. Despite considerable amplitudes of that part of the spectral density which contains correlations in site energy fluctuations, the effect of these correlations on the exciton population dynamics and dephasing of coherences is negligible. The inhomogeneous charge distribution of the protein, which causes variations in local pigment-protein coupling constants of the normal modes, is responsible for this effect. It is seen thereby that the same building principle that is used by nature to create an excitation energy funnel in the FMO protein also allows for efficient dissipation of the excitons' excess energy.

  5. Normal Weight with Central Obesity, Physical Activity, and Functional Decline: Data from the Osteoarthritis Initiative

    PubMed Central

    Batsis, John A.; Zbehlik, Alicia J.; Scherer, Emily A.; Barre, Laura K.; Bartels, Stephen J.

    2015-01-01

    OBJECTIVES To identify the risks of the combination of normal body mass index (BMI) and central obesity (normal weight and central obesity (NWCO)) on physical activity and function. DESIGN Longitudinal Osteoarthritis Initiative Study. SETTING Community based. PARTICIPANTS Adults aged 60 and older at risk of osteoarthritis (N= 2,210; mean age 68, range 67.1–69.0) were grouped according to BMI (normal 18.5–24.9 kg/m2, overweight 25.0–29.9 kg/m2, obese ≥30.0 kg/m2). High waist circumference (WC) was defined as greater than 88 cm for women and greater than 102 cm for men. Subjects were subcategorized according to WC (five categories). Subjects with normal BMI and a large WC were considered to have NWCO (n=280, 12.7%). MEASUREMENTS Six-year changes in the Physical Component Summary of the Medical Outcomes Study 12-item Short Form Survey (PCS), Physical Activity Scale for the Elderly (PASE), and Late-Life Function and Disability Index (LL-FDI) were examined. The association between BMI and WC over 6 years was assessed (reference normal BMI, normal WC). Stratified analyses were performed according to age (60–69; ≥70). RESULTS Physical component scores, PASE, and LL-FDI declined with time. Mean PASE scores at 6 years differed between the NWCO group and the group with normal BMI and WC (117.7 vs 141.5), but rate of change from baseline to 6 years was not significantly different (p=.35). In adjusted models, those with NWCO had greater decline in PCS over time, particularly those aged 70 and older than those with normal BMI and WC (time interaction β=–0.37, 95% confidence interval=–0.68 to –0.06). CONCLUSION NWCO in older adults at risk of osteoarthritis may be a risk factor for declining function and physical activity, particularly in those aged 70 and older, suggesting the value of targeting those with NWCO who would otherwise be labeled as low risk. PMID:26173812

  6. Imaging the complexity of an active normal fault system: The 1997 Colfiorito (central Italy) case study

    USGS Publications Warehouse

    Chiaraluce, L.; Ellsworth, W.L.; Chiarabba, C.; Cocco, M.

    2003-01-01

    Six moderate magnitude earthquakes (5 < Mw < 6) ruptured normal fault segments of the southern sector of the North Apennine belt (central Italy) in the 1997 Colfiorito earthquake sequence. We study the progressive activation of adjacent and nearby parallel faults of this complex normal fault system using ???1650 earthquake locations obtained by applying a double-difference location method, using travel time picks and waveform cross-correlation measurements. The lateral extent of the fault segments range from 5 to 10 km and make up a broad, ???45 km long, NW trending fault system. The geometry of each segment is quite simple and consists of planar faults gently dipping toward SW with an average dip of 40??-45??. The fault planes are not listric but maintain a constant dip through the entire seismogenic volume, down to 8 km depth. We observe the activation of faults on the hanging wall and the absence of seismicity in the footwall of the structure. The observed fault segmentation appears to be due to the lateral heterogeneity of the upper crust: preexisting thrusts inherited from Neogene's compressional tectonic intersect the active normal faults and control their maximum length. The stress tensor obtained by inverting the six main shock focal mechanisms of the sequence is in agreement with the tectonic stress active in the inner chain of the Apennine, revealing a clear NE trending extension direction. Aftershock focal mechanisms show a consistent extensional kinematics, 70% of which are mechanically consistent with the main shock stress field.

  7. Design and control of a prosthetic leg for above-knee amputees operated in semi-active and active modes

    NASA Astrophysics Data System (ADS)

    Park, Jinhyuk; Yoon, Gun-Ha; Kang, Je-Won; Choi, Seung-Bok

    2016-08-01

    This paper proposes a new prosthesis operated in two different modes; the semi-active and active modes. The semi-active mode is achieved from a flow mode magneto-rheological (MR) damper, while the active mode is obtained from an electronically commutated (EC) motor. The knee joint part of the above knee prosthesis is equipped with the MR damper and EC motor. The MR damper generates reaction force by controlling the field-dependent yield stress of the MR fluid, while the EC motor actively controls the knee joint angle during gait cycle. In this work, the MR damper is designed as a two-end type flow mode mechanism without air chamber for compact size. On other hand, in order to predict desired knee joint angle to be controlled by EC motor, a polynomial prediction function using a statistical method is used. A nonlinear proportional-derivative controller integrated with the computed torque method is then designed and applied to both MR damper and EC motor to control the knee joint angle. It is demonstrated that the desired knee joint angle is well achieved in different walking velocities on the ground ground.

  8. WS(2)/fluorine mica (FM) saturable absorbers for all-normal-dispersion mode-locked fiber laser.

    PubMed

    Li, Lu; Jiang, Shouzhen; Wang, Yonggang; Wang, Xi; Duan, Lina; Mao, Dong; Li, Zhen; Man, Baoyuan; Si, Jinhai

    2015-11-01

    The report firstly propose a new WS(2) absorber based on fluorine mica (FM) substrate. The WS(2) material was fabricated by thermal decomposition method. The FM was stripped into one single layer as thin as 20 μm and deposited WS(2) on it, which can be attached to the fiber flank without causing the laser deviation. Similar to quartz, the transmission rate of FM is as high as 90% at near infrared wavelength from one to two micrometers. Furthermore, FM is a highly elastic material so that it is not easy to break off even its thickness was only 20 μm. On the contrary, quartz is hard to be processed and easy to break off when its thickness is less than 100 μm. Compared to organic matrix such as polyvinyl alcohol (PVA), FM has higher softening temperature, heat dissipation and laser damage threshold than those of organic composites. In our work, the modulation depth (MD) and non-saturable losses (NLs) of this kind of saturable absorber were measured to be 5.8% and 14.8%, respectively. The WS(2)/FM absorber has a high damage threshold of 406 MW/cm(2), two times higher than that of WS(2)/PVA. By incorporating the saturable absorber into Yb-doped fiber laser cavity, a mode-locked fiber laser was achieved with central wavelength of 1052.45 nm. The repetition rate was 23.26 MHz and the maximum average output power was 30 mW. The long term stability of working was proved to be good too. The results indicate that WS(2)/FM film is a practical nonlinear optical material for photonic applications.

  9. Dynamical response of the Galileo Galilei on the ground rotor to test the equivalence principle: Theory, simulation, and experiment. I. The normal modes

    SciTech Connect

    Comandi, G.L.; Chiofalo, M.L.; Toncelli, R.; Bramanti, D.; Polacco, E.; Nobili, A.M.

    2006-03-15

    Recent theoretical work suggests that violation of the equivalence principle might be revealed in a measurement of the fractional differential acceleration {eta} between two test bodies-of different compositions, falling in the gravitational field of a source mass--if the measurement is made to the level of {eta}{approx_equal}10{sup -13} or better. This being within the reach of ground based experiments gives them a new impetus. However, while slowly rotating torsion balances in ground laboratories are close to reaching this level, only an experiment performed in a low orbit around the Earth is likely to provide a much better accuracy. We report on the progress made with the 'Galileo Galilei on the ground' (GGG) experiment, which aims to compete with torsion balances using an instrument design also capable of being converted into a much higher sensitivity space test. In the present and following articles (Part I and Part II), we demonstrate that the dynamical response of the GGG differential accelerometer set into supercritical rotation-in particular, its normal modes (Part I) and rejection of common mode effects (Part II)-can be predicted by means of a simple but effective model that embodies all the relevant physics. Analytical solutions are obtained under special limits, which provide the theoretical understanding. A simulation environment is set up, obtaining a quantitative agreement with the available experimental data on the frequencies of the normal modes and on the whirling behavior. This is a needed and reliable tool for controlling and separating perturbative effects from the expected signal, as well as for planning the optimization of the apparatus.

  10. Dynamical response of the Galileo Galilei on the ground rotor to test the equivalence principle: Theory, simulation, and experiment. I. The normal modes

    NASA Astrophysics Data System (ADS)

    Comandi, G. L.; Chiofalo, M. L.; Toncelli, R.; Bramanti, D.; Polacco, E.; Nobili, A. M.

    2006-03-01

    Recent theoretical work suggests that violation of the equivalence principle might be revealed in a measurement of the fractional differential acceleration η between two test bodies—of different compositions, falling in the gravitational field of a source mass—if the measurement is made to the level of η ≃10-13 or better. This being within the reach of ground based experiments gives them a new impetus. However, while slowly rotating torsion balances in ground laboratories are close to reaching this level, only an experiment performed in a low orbit around the Earth is likely to provide a much better accuracy. We report on the progress made with the "Galileo Galilei on the ground" (GGG) experiment, which aims to compete with torsion balances using an instrument design also capable of being converted into a much higher sensitivity space test. In the present and following articles (Part I and Part II), we demonstrate that the dynamical response of the GGG differential accelerometer set into supercritical rotation—in particular, its normal modes (Part I) and rejection of common mode effects (Part II)—can be predicted by means of a simple but effective model that embodies all the relevant physics. Analytical solutions are obtained under special limits, which provide the theoretical understanding. A simulation environment is set up, obtaining a quantitative agreement with the available experimental data on the frequencies of the normal modes and on the whirling behavior. This is a needed and reliable tool for controlling and separating perturbative effects from the expected signal, as well as for planning the optimization of the apparatus.

  11. Cardiac Time Intervals by Tissue Doppler Imaging M-Mode: Normal Values and Association with Established Echocardiographic and Invasive Measures of Systolic and Diastolic Function

    PubMed Central

    Mogelvang, Rasmus; de Knegt, Martina Chantal; Olsen, Flemming Javier; Galatius, Søren; Jensen, Jan Skov

    2016-01-01

    Purpose To define normal values of the cardiac time intervals obtained by tissue Doppler imaging (TDI) M-mode through the mitral valve (MV). Furthermore, to evaluate the association of the myocardial performance index (MPI) obtained by TDI M-mode (MPITDI) and the conventional method of obtaining MPI (MPIConv), with established echocardiographic and invasive measures of systolic and diastolic function. Methods In a large community based population study (n = 974), where all are free of any cardiovascular disease and cardiovascular risk factors, cardiac time intervals, including isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), and ejection time (ET) were obtained by TDI M-mode through the MV. IVCT/ET, IVRT/ET and the MPI ((IVRT+IVCT)/ET) were calculated. We also included a validation population (n = 44) of patients who underwent left heart catheterization and had the MPITDI and MPIConv measured. Results IVRT, IVRT/ET and MPI all increased significantly with increasing age in both genders (p<0.001 for all). IVCT, ET, IVRT/ET, and MPI differed significantly between males and females, displaying that women, in general exhibit better cardiac function. MPITDI was significantly associated with invasive (dP/dt max) and echocardiographic measures of systolic (LVEF, global longitudinal strain and global strainrate s) and diastolic function (e’, global strainrate e)(p<0.05 for all), whereas MPIConv was significantly associated with LVEF, e’ and global strainrate e (p<0.05 for all). Conclusion Normal values of cardiac time intervals differed between genders and deteriorated with increasing age. The MPITDI (but not MPIConv) is associated with most invasive and established echocardiographic measures of systolic and diastolic function. PMID:27093636

  12. Quantification of telomerase activity in normal oral mucosal tissue and oral squamous cell carcinoma

    PubMed Central

    Rai, Arpita; Naikmasur, Venkatesh G.; Sattur, Atul

    2016-01-01

    Background and Objective: The role of telomeres and telomerase in oral cancer is an area of much recent interest. The understanding of the role of telomere biology, the end replication problem leading to genomic instability and the reactivation of telomerase, is absolutely critical to our understanding of oral cancer, and more so, to our ability of early diagnosis and developing novel therapies and cancer prevention approaches. The aim of the present study was to quantify telomerase activity (TA) in oral squamous cell carcinoma (OSCC) and normal oral mucosa and assess the role of telomerase as diagnostic and prognostic marker of oral malignancy. Materials and Methods: We quantified TA in 45 patients with OSCC and 20 normal oral mucosal specimens using polymerase chain reaction-based telomeric repeat amplification protocol assay and compared it with the clinical status and grade of malignancy. Results: TA was detected in 89% of malignant and 5% of normal oral mucosal tissue. The TA levels ranged from 0.28 to 6.91 (mean 2.05, standard deviation [SD] 1.33) in OSCC and 0.21 to 1.09 (mean 0.54, SD 0.27) in normal oral mucosa. There was no relationship between TA levels and clinical stages, site of the lesion, history of adverse habits, or sex of the patient. However, under the WHO classification, there were significant differences (P < 0.00) between Grades I, II, and III. Furthermore, increasing age of the patient significantly correlated with TA. Interpretation and Conclusion: The results of the present study indicate that activation of TA is frequent in OSCC. Statistically significant difference in quantified telomerase levels of OSCC and normal oral mucosa (P < 0.00) demonstrates the significant clinical usefulness of telomerase activation as a valuable marker for diagnosis while significant correlation of TA with grades of malignancy indicates its effectiveness as marker for prognosis of OSCC.

  13. Active mode locking of quantum cascade lasers in an external ring cavity.

    PubMed

    Revin, D G; Hemingway, M; Wang, Y; Cockburn, J W; Belyanin, A

    2016-05-05

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents.

  14. Active mode locking of quantum cascade lasers in an external ring cavity

    PubMed Central

    Revin, D. G.; Hemingway, M.; Wang, Y.; Cockburn, J. W.; Belyanin, A.

    2016-01-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents. PMID:27147409

  15. Active mode locking of quantum cascade lasers in an external ring cavity

    NASA Astrophysics Data System (ADS)

    Revin, D. G.; Hemingway, M.; Wang, Y.; Cockburn, J. W.; Belyanin, A.

    2016-05-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents.

  16. Cholesterol and triglycerides lowering activities of caraway fruits in normal and streptozotocin diabetic rats.

    PubMed

    Lemhadri, A; Hajji, L; Michel, J-B; Eddouks, M

    2006-07-19

    The purpose of this study was to examine the effect of single and repeated oral administration of the aqueous extract of Carum carvi L. fruits at a dose of (20mg/kg) on lipid metabolism in normal and streptozotocin-induced diabetic rats (STZ). After a single oral administration, Carum carvi extract produced a significant decrease on triglycerides levels in normal rats (p<0.05). In STZ diabetic rats, cholesterol levels were decreased significantly 6h after Carum carvi treatment (p<0.05). On the other hand, repeated oral administration of Carum carvi extract exhibited a significant hypotriglyceridemic and hypocholesterolemic activities in both normal (p<0.01 and <0.001 respectively) and STZ diabetic rats (p<0.001) 15 days after Carum carvi treatment. We conclude that the aqueous extract of Carum carvi (20mg/kg) exhibits a potent lipid lowering activity in both normal and severe hyperglycemic rats after repeated oral administration of Carum carvi aqueous extract.

  17. Unravelling the competing influence of regional uplift and active normal faulting in SW Calabria, Italy

    NASA Astrophysics Data System (ADS)

    Whittaker, Alex; Roda Boluda, Duna; Boulton, Sarah; Erhardt, Sebastian

    2015-04-01

    The Neogene geological and geomorphological evolution of Southern Italy is complex and is fundamentally controlled by the subduction of the Ionian slab along the Apennine belt from the Calabrian Arc, and back-arc extension driven by trench rollback. In the area of Calabria and the Straits of Messina the presence of (i) uplifted, deformed and dissected basin sediments and marine terraces, ranging in age from the early to mid-Pleistocene and (ii) seismicity associated with NE-SW normal faults that have well-developed footwall topography and triangular facets have led workers to suggest that both significant regional uplift and extensional faulting in SW Calabria have played a role in generating relief in the area since the mid Pleistocene. However, there is considerable uncertainty in the rates of total surface uplift relative to sea level in both time and space, and the relative partitioning of this uplift between a mantle-driven regional signal, potentially related to a slab tear, and the active extensional structures. Additionally, despite the widespread recognition of normal faults in Calabria to which historical earthquakes are often linked, there is much less agreement on (i) which ones are active and for what length of time; (ii) how the faults interact; and (iii) what their throw and throw rates are. In particular, the ability to resolve both regional uplift and normal faulting in SW Calabria is essential in order to fully understand the tectonic history of the region, while an understanding of location and slip rate of active faults, in an area where the population numbers more than two million people, is essential to assess regional seismic hazards. Here we address these important questions using a combination of tectonic geomorphology and structural geology. We critically examine existing constraints on the rates and distribution of active normal faulting and regional uplift in the area, and we derive new constraints on the along-strike variation in throw

  18. Phosphatidic acid phosphatase activity in subcellular fractions of normal and dystrophic human muscle.

    PubMed

    Kunze, D; Rüstow, B; Olthoff, D; Jung, K

    1985-03-15

    Biopsy samples from normal and dystrophic human muscle (Duchenne type) were fractionated by differential centrifugation and microsomes, mitochondria and cytosol were assayed for phosphatidic acid phosphatase (EC 3.1.3.4) and marker enzymes of mitochondria and cytosol. The activity of phosphatidic acid phosphatase was significantly lower in microsomes and higher in cytosol and mitochondria of dystrophic muscle than in the corresponding subcellular fractions of normal muscle. The results support an explanation of earlier findings that there is reduced G3P incorporation into diglycerides and phosphatidylcholine and a qualitative and quantitative change in the amount of phosphatidylcholine in dystrophic microsomes. The possible reasons for the reduction in the activity of only microsomal PA-P-ase were discussed.

  19. Actively mode-locked fiber ring laser by intermodal acousto-optic modulation.

    PubMed

    Bello-Jiménez, M; Cuadrado-Laborde, C; Sáez-Rodríguez, D; Diez, A; Cruz, J L; Andrés, M V

    2010-11-15

    We report an actively mode-locked fiber ring laser. A simple and low-insertion-loss acousto-optic modulator driven by standing flexural waves, which couples core-to-cladding modes in a standard single-mode optical fiber, is used as an active mechanism for mode locking. Among the remarkable features of the modulator, we mention its high modulation depth (72%), broad bandwidth (187 GHz), easy tunability in the optical wavelength, and low insertion losses (0.7 dB). The narrowest optical pulses obtained were of 95 ps time width, 21 mW peak power, repetition rate of 4.758 MHz, and 110 mW of pump power.

  20. 4-Alkynylphenylsilatranes: Insecticidal activity, mammalian toxicity, and mode of action

    SciTech Connect

    Horsham, M.A.; Palmer, C.J.; Cole, L.M.; Casida, J.E. )

    1990-08-01

    4-Ethynyl- and 4-(prop-1-ynyl)phenylsilatranes (N(CH{sub 2}CH{sub 2}O){sub 3}SiR, R = C{sub 6}H{sub 4}-4-C{triple bond}CH or C{sub 6}H{sub 4}-4-C{triple bond}CCH{sub 3}) are highly toxic to houseflies (pretreated with piperonyl butoxide) and milkweed bugs (topical LD{sub 50}s 3-14 {mu}g/g) and to mice (intraperitoneal LD{sub 50}s 0.4-0.9 mg/kg), and they are moderately potent inhibitors of the ({sup 35}S)-tert-butylbicyclophosphorothionate or TBPS binding site (GABA-gated chloride channel) of mouse brain membranes. Scatchard analysis indicates noncompetitive interaction of 4-ethynylphenylsilatrane with the TBPS binding site. Phenylsilatrane analogues with 4-substituents of H, CH{sub 3}, Cl, Br, and C{triple bond}CSi(CH{sub 3}){sub 3} are highly toxic to mice but have little or no activity in the insect and receptor assays. Radioligand binding studies with (4-{sup 3}H)phenylsilatrane failed to reveal a specific binding site in mouse brain. Silatranes with R = H, CH{sub 3}, CH{sub 2}Cl, CH{double bond}CH{sub 2}, OCH{sub 2}CH{sub 3}, and C{sub 6}H{sub 4}-4-CH{sub 2}CH{sub 3} are of little or no activity in the insect and mouse toxicity and TBPS binding site assays as are the trithia and monocyclic analogues of phenylsilatrane. 4-Alkynylphenylsilatranes are new probes to examine the GABA receptor-ionophore complex of insects and mammals.

  1. [Bioelectric activity of cervix uteri in normal menstrual cycle and in the syndrome of sclerocystic ovaries].

    PubMed

    Rymashevskiĭ, V K; Kozhin, A A; Chzhan Chun'; Gorchakov, L A

    1974-10-01

    34 20-26 year old women with anovulatory cycles with the Stein syndrome and 5 women with normal menstrual cycles were studied in regard to bioelectric cervical activity by means of a vaginal probe and the micrograph ''Medicore.'' In the control group, an increase of progesterone in the 2nd phase of the cycle led to a decrease in the electromyographic (EMG) amplitude. In the anovulatory cycle, the extended activity of estrogens and minimal amount of progesterone stimulated a high tone of uterine impulses, which was substantiated by a high EMG proved to be effective and useful in the diagnosis of gynecological patients. PMID:4440834

  2. High normalized beta plasmas exceeding the ideal stability limit and projected RWM active stabilization performance using newly installed feedback sensors in KSTAR

    NASA Astrophysics Data System (ADS)

    Park, Y. S.; Sabbagh, S. A.; Berkery, J. W.; Bialek, J. M.; Yoon, S. W.; Jeon, Y. M.; Bak, J. G.; Ko, W. H.; Hahn, S. H.; Bae, C.; Bae, Y. S.; in, Y. K.; Kim, J.; Lee, S. G.; Kwak, J. G.; Oh, Y. K.; Park, H. K.; Choi, M. J.; Yun, G. S.

    2015-11-01

    H-mode plasma operation of KSTAR has been expanded to significantly surpass the ideal MHD no-wall beta limit by achieving normalized beta up to 4.3 while reducing plasma internal inductance to near 0.7 exceeding the computed n = 1 ideal no-wall limit by a factor of 1.6. These high normalized beta values have been achieved in discharges having BT in the range 0.9-1.1 T after the plasma reached flattop current of 0.35-0.4 MA, with the highest neutral beam heating power of 4 MW. A significant conclusion of the analysis of these plasmas is that low- n global kink/ballooning or RWMs were not detected, and therefore were not the cause of the plasma termination. Advances from the 2015 run campaign aiming to achieve prolonged pulse duration at maximum normalized beta and to subsequently investigate the MHD stability of these plasmas will be reported. As KSTAR H-mode operation can now routinely surpass the ideal no-wall stability limit, n = 1 RWM active control is planned for the device. RWM active feedback using a newly installed set of poloidal magnetic field sensors mounted on the passive stabilizer plates and designed for optimal performance is analyzed using the VALEN-3D code. The advantages of the new sensors over other device sensors for RWM active control are discussed. Supported by U.S. DOE grant DE-FG02-99ER54524.

  3. Influence of Activity Mode on Feeling States of High School Physical Education Students

    ERIC Educational Resources Information Center

    Hannon, James C.; Pellet, Tracey L.

    2005-01-01

    The purpose of this study was to determine if changes in positive well-being, psychological distress, fatigue, and enjoyment vary as a function of physical activity mode. Fifty-five senior high school students participated in one of four fitness activities including two defined as traditional (running and step-aerobics) and two defined as…

  4. Identification of a potent synthetic FXR agonist with an unexpected mode of binding and activation

    SciTech Connect

    Soisson, Stephen M.; Parthasarathy, Gopalakrishnan; Adams, Alan D.; Sahoo, Soumya; Sitlani, Ayesha; Sparrow, Carl; Cui, Jisong; Becker, Joseph W.

    2008-07-08

    The farnesoid X receptor (FXR), a member of the nuclear hormone receptor family, plays important roles in the regulation of bile acid and cholesterol homeostasis, glucose metabolism, and insulin sensitivity. There is intense interest in understanding the mechanisms of FXR regulation and in developing pharmaceutically suitable synthetic FXR ligands that might be used to treat metabolic syndrome. We report here the identification of a potent FXR agonist (MFA-1) and the elucidation of the structure of this ligand in ternary complex with the human receptor and a coactivator peptide fragment using x-ray crystallography at 1.9-{angstrom} resolution. The steroid ring system of MFA-1 binds with its D ring-facing helix 12 (AF-2) in a manner reminiscent of hormone binding to classical steroid hormone receptors and the reverse of the pose adopted by naturally occurring bile acids when bound to FXR. This binding mode appears to be driven by the presence of a carboxylate on MFA-1 that is situated to make a salt-bridge interaction with an arginine residue in the FXR-binding pocket that is normally used to neutralize bound bile acids. Receptor activation by MFA-1 differs from that by bile acids in that it relies on direct interactions between the ligand and residues in helices 11 and 12 and only indirectly involves a protonated histidine that is part of the activation trigger. The structure of the FXR:MFA-1 complex differs significantly from that of the complex with a structurally distinct agonist, fexaramine, highlighting the inherent plasticity of the receptor.

  5. The chaperone activity and toxicity of ambroxol on Gaucher cells and normal mice.

    PubMed

    Luan, Zhuo; Li, Linjing; Higaki, Katsumi; Nanba, Eiji; Suzuki, Yoshiyuki; Ohno, Kousaku

    2013-04-01

    Gaucher disease (GD), caused by a defect of acid β-glucosidase (β-Glu), is one of the most common sphingolipidoses. Recently, ambroxol, an FDA-approved drug used to treat airway mucus hypersecretion and hyaline membrane disease in newborns, was identified as a chemical chaperone for GD. In the present study, we investigated the chaperone activity and toxicity of ambroxol on both cultured GD patient cells and normal mice. We found that ambroxol treatment significantly increased N370S, F213I, N188S/G193W and R120W mutant β-Glu activities in GD fibroblasts with low cytotoxicity. Additionally, we measured the β-Glu activity in the tissues of normal mice which received water containing increasing concentrations of ambroxol ad libitum for one week. No serious adverse effect was observed during this experiment. Ambroxol significantly increased the β-Glu activity in the spleen, heart and cerebellum of the mice. This result showed its oral availability and wide distribution and chaperone activity in the tissues, including the brain, and its lack of acute toxicity. These characteristics of ambroxol would make it a potential therapeutic chaperone in the treatment of GD with neurological manifestations.

  6. The chaperone activity and toxicity of ambroxol on Gaucher cells and normal mice.

    PubMed

    Luan, Zhuo; Li, Linjing; Higaki, Katsumi; Nanba, Eiji; Suzuki, Yoshiyuki; Ohno, Kousaku

    2013-04-01

    Gaucher disease (GD), caused by a defect of acid β-glucosidase (β-Glu), is one of the most common sphingolipidoses. Recently, ambroxol, an FDA-approved drug used to treat airway mucus hypersecretion and hyaline membrane disease in newborns, was identified as a chemical chaperone for GD. In the present study, we investigated the chaperone activity and toxicity of ambroxol on both cultured GD patient cells and normal mice. We found that ambroxol treatment significantly increased N370S, F213I, N188S/G193W and R120W mutant β-Glu activities in GD fibroblasts with low cytotoxicity. Additionally, we measured the β-Glu activity in the tissues of normal mice which received water containing increasing concentrations of ambroxol ad libitum for one week. No serious adverse effect was observed during this experiment. Ambroxol significantly increased the β-Glu activity in the spleen, heart and cerebellum of the mice. This result showed its oral availability and wide distribution and chaperone activity in the tissues, including the brain, and its lack of acute toxicity. These characteristics of ambroxol would make it a potential therapeutic chaperone in the treatment of GD with neurological manifestations. PMID:22682976

  7. Quantifying radio-mode feedback from Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Shabala, Stanislav

    2015-08-01

    Galaxy formation models routinely invoke feedback from radio-loud Active Galactic Nuclei to explain the observed masses and red colours of the most massive galaxies since z~1. Whether or not the observed AGN population can provide the required feedback, however, is an open question.We present a new dynamical model that relates AGN physical parameters to the observed properties of radio AGN. This model combines a traditional approach to modeling radio AGN with a semi-analytic description of AGN environments. The model reproduces a number of key features of the observed radio AGN populations, and we determine the energetics (specifically, jet kinetic powers and AGN lifetimes) of the observed local (z<0.1) radio AGN population, as a function of host galaxy properties.We find a broad distribution of jet powers that is largely independent of host galaxy mass, consistent with the idea that these radio AGN are fed by gas cooling from hot haloes in near heating-cooling equilibrium. On the other hand, the duration of the AGN phase appears strongly mass-dependent: massive galaxies host AGN that are longer-lived, and can therefore impart feedback for longer and on larger spatial scales. Finally, we compare the cumulative AGN energy output from ubiquitous weak AGN with their rare powerful counterparts, and find that radio AGN of all luminosities deliver a comparable amount of energy to their surroundings.I will outline how this approach can provide useful insights into AGN triggering and feedback mechanisms, as well as be used to correct for selection effects in large radio surveys. I will also outline the challenges (and solutions) to performing an AGN energetics analysis at high redshift.

  8. PCSK6-mediated corin activation is essential for normal blood pressure

    PubMed Central

    Chen, Shenghan; Cao, Pengxiu; Dong, Ningzheng; Peng, Jianhao; Zhang, Chunyi; Wang, Hao; Zhou, Tiantian; Yang, Junhua; Zhang, Yue; Martelli, Elizabeth E; Prasad, Sathyamangla V Naga; Miller, Rachel E; Malfait, Anne-Marie; Zhou, Yiqing; Wu, Qingyu

    2016-01-01

    Hypertension is the most common cardiovascular disease, afflicting >30% of adults1. The cause of hypertension in most individuals remains unknown2,3, suggesting that additional contributing factors have yet to be discovered. Corin is a serine protease that activates the natriuretic peptides, thereby regulating blood pressure4. It is synthesized as a zymogen that is activated by proteolytic cleavage. CORIN variants and mutations impairing corin activation have been identified in people with hypertension and pre-eclampsia5–9. To date, however, the identity of the protease that activates corin remains elusive. Here we show that proprotein convertase subtilisin/kexin-6 (PCSK6, also named PACE4; ref. 10) cleaves and activates corin. In cultured cells, we found that corin activation was inhibited by inhibitors of PCSK family proteases and by small interfering RNAs blocking PCSK6 expression. Conversely, PCSK6 overexpression enhanced corin activation. In addition, purified PCSK6 cleaved wild-type corin but not the R801A variant that lacks the conserved activation site. Pcsk6-knockout mice developed salt-sensitive hypertension, and corin activation and pro-atrial natriuretic peptide processing activity were undetectable in these mice. Moreover, we found that CORIN variants in individuals with hypertension and pre-eclampsia were defective in PCSK6-mediated activation. We also identified a PCSK6 mutation that impaired corin activation activity in a hypertensive patient. Our results indicate that PCSK6 is the long-sought corin activator and is important for sodium homeostasis and normal blood pressure. PMID:26259032

  9. Lifetime and conductance of acetylcholine-activated channels in normal and denervated toad sartorius muscle.

    PubMed Central

    Gage, P W; Hamill, O P

    1980-01-01

    1. The average lifetime and conductance of acetylcholine-activated channels were measured in normal and denervated, voltage-clamped toad sartorius muscle fibres at 10 degrees C. 2. The null potential was -4 +/- 1 mV for subsynaptic channels in normal fibres and -6 +/- 3 mV for extrasynaptic channels in denervated fibres. 3. There was a linear relationship between variance of conductance fluctuations and mean conductance for acetylcholine-induced currents up to 50 nA, in denervated fibres clamped at -50 mV. The ratio gave a channel conductance of 14 pS. 4. At the same membrane potential, the average lifetime of extrasynaptic channels in denervated fibres was approximately double, whereas channel conductance was approximately half, that of subsynaptic channels in normal fibres: there was little difference in net charge transfer through the two types of channel under similar conditions. 5. Single channel conductance increased, whereas average channel lifetime decreased, as the membrane potential became more positive (depolarized). The effect of potential on channel lifetime and conductance was more pronounced in denervated than in normal fibres. PMID:6767026

  10. [Influence of naloxone on hypothalamic L-aminopeptidase activity in the normal and ovariectomized rat].

    PubMed

    Montilla, P; Vigara, M R; Muñoz, M C; Varo, A; Clavero, M R

    1986-09-01

    The effect of naloxone on the L-leucinaminopeptidase (LAP) activity has been determined in the hypothalamus of normal female rats or after different periods of time from ovariectomy (15th or 30th day). Castration at 15th and 30th days produced a not very important fall of LAP activity. The naloxone injections (2.5 or 5 mg/kg vía i.p.) determined a significant decrease in LAP activity in the intact and ovariectomized rats, greater for 5 mg/kg. A significant LAP activity decrease was found only after a 30 day postcastration period when naloxone treated intact animals were compared with the castrated rats. These data are discussed in relation to the physiological significance of brain peptidases and the pharmacological effect of naloxone on the function of the hypothalamic-pituitary-gonadal axis.

  11. Cytochemically demonstrable B-glucuronidase activity in normal and neoplastic human lymphoid cells.

    PubMed

    Machin, G A; Halper, J P; Knowles, D M

    1980-12-01

    Mononuclear cell suspensions were prepared from 40 normal peripheral blood and lymphoid tissue specimens and 42 neoplastic specimens obtained from patients with malignant lymphoma and lymphocytic leukemia. These suspensions were analyzed for la antigens, surface immunoglobulin (Slg), sheep erythrocyte (E) rosette formation and, in some instances, acid alpha-naphthyl acetate esterase (ANAE) activity. The results of these studies were correlated with the expression of cytochemically demonstrable BG activity. The percentage of BG+ lymphocytes was found to be comparable, within 10%, to the percentage of E+ (T) cells in the majority of normal, non-neoplastic peripheral blood, tonsil, spleen, and lymph node specimens examined. Occasionally, the percentage of E+ cells exceeded the percentage of BG+ cells by 20% or more, suggesting the presence of an E+BG- T cell subpopulation. BG+ B lymphocytes were only demonstrated in 1 of 40 non-neoplastic lymphoid specimens. The neoplastic B cells in each of 14 B cell (la+Slg+E-) lymphomas were BG-. However, a variable proportion of the neoplastic cells isolated from 6 cases of B cell chronic lymphocytic leukemia and neoplastic plasma cells isolated from 7 cases of multiple myeloma expressed BG activity. Thus, it appears that both normal and neoplastic BG- and BG+ B lymphocyte populations exist; the latter may be related to a state of activation or a stage of B cell differentiation. The neoplastic cells isolated from 4 T cell (la-Slg-E+) malignancies were BG+ while those isolated from 3 T cell malignancies were BG-. The variable expression of BG activity by T cell malignancies may be related to T cell differentiation. Investigation of BG expression by T cell derived malignancies may prove useful in sorting out T cell phenotypes. PMID:7437515

  12. Subthalamic, not striatal, activity correlates with basal ganglia downstream activity in normal and parkinsonian monkeys

    PubMed Central

    Deffains, Marc; Iskhakova, Liliya; Katabi, Shiran; Haber, Suzanne N; Israel, Zvi; Bergman, Hagai

    2016-01-01

    The striatum and the subthalamic nucleus (STN) constitute the input stage of the basal ganglia (BG) network and together innervate BG downstream structures using GABA and glutamate, respectively. Comparison of the neuronal activity in BG input and downstream structures reveals that subthalamic, not striatal, activity fluctuations correlate with modulations in the increase/decrease discharge balance of BG downstream neurons during temporal discounting classical condition task. After induction of parkinsonism with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), abnormal low beta (8-15 Hz) spiking and local field potential (LFP) oscillations resonate across the BG network. Nevertheless, LFP beta oscillations entrain spiking activity of STN, striatal cholinergic interneurons and BG downstream structures, but do not entrain spiking activity of striatal projection neurons. Our results highlight the pivotal role of STN divergent projections in BG physiology and pathophysiology and may explain why STN is such an effective site for invasive treatment of advanced Parkinson's disease and other BG-related disorders. DOI: http://dx.doi.org/10.7554/eLife.16443.001 PMID:27552049

  13. Normal amygdala activation but deficient ventrolateral prefrontal activation in adults with bipolar disorder during euthymia.

    PubMed

    Foland-Ross, Lara C; Bookheimer, Susan Y; Lieberman, Matthew D; Sugar, Catherine A; Townsend, Jennifer D; Fischer, Jeffrey; Torrisi, Salvatore; Penfold, Conor; Madsen, Sarah K; Thompson, Paul M; Altshuler, Lori L

    2012-01-01

    Functional neuroimaging studies have implicated the involvement of the amygdala and ventrolateral prefrontal cortex (vlPFC) in the pathophysiology of bipolar disorder. Hyperactivity in the amygdala and hypoactivity in the vlPFC have been reported in manic bipolar patients scanned during the performance of an affective faces task. Whether this pattern of dysfunction persists during euthymia is unclear. Using functional magnetic resonance imaging (fMRI), 24 euthymic bipolar and 26 demographically matched healthy control subjects were scanned while performing an affective task paradigm involving the matching and labeling of emotional facial expressions. Neuroimaging results showed that, while amygdala activation did not differ significantly between groups, euthymic patients showed a significant decrease in activation of the right vlPFC (BA47) compared to healthy controls during emotion labeling. Additionally, significant decreases in activation of the right insula, putamen, thalamus and lingual gyrus were observed in euthymic bipolar relative to healthy control subjects during the emotion labeling condition. These data, taken in context with prior studies of bipolar mania using the same emotion recognition task, could suggest that amygdala dysfunction may be a state-related abnormality in bipolar disorder, whereas vlPFC dysfunction may represent a trait-related abnormality of the illness. Characterizing these patterns of activation is likely to help in understanding the neural changes related to the different mood states in bipolar disorder, as well as changes that represent more sustained abnormalities. Future studies that assess mood-state related changes in brain activation in longitudinal bipolar samples would be of interest. PMID:21854858

  14. Multiple dynamo modes as a mechanism for long-term solar activity variations

    NASA Astrophysics Data System (ADS)

    Käpylä, M. J.; Käpylä, P. J.; Olspert, N.; Brandenburg, A.; Warnecke, J.; Karak, B. B.; Pelt, J.

    2016-05-01

    Context. Solar magnetic activity shows both smooth secular changes, such as the modern Grand Maximum, and quite abrupt drops that are denoted as grand minima, such as the Maunder Minimum. Direct numerical simulations (DNS) of convection-driven dynamos offer one way of examining the mechanisms behind these events. Aims: In this work, we analyze a solution of a solar-like DNS that was evolved for roughly 80 magnetic cycles of 4.9 years and where epochs of irregular behavior are detected. The emphasis of our analysis is to find physical causes for such behavior. Methods: The DNS employed is a semi-global (wedge-shaped) magnetoconvection model. For the data analysis tasks we use Ensemble Empirical Mode Decomposition and phase dispersion methods, as they are well suited for analyzing cyclic (non-periodic) signals. Results: A special property of the DNS is the existence of multiple dynamo modes at different depths and latitudes. The dominant mode is solar-like (equatorward migration at low latitudes and poleward at high latitudes). This mode is accompanied by a higher frequency mode near the surface and at low latitudes, showing poleward migration, and a low-frequency mode at the bottom of the convection zone. The low-frequency mode is almost purely antisymmetric with respect to the equator, while the dominant mode has strongly fluctuating mixed parity. The overall behavior of the dynamo solution is extremely complex, exhibiting variable cycle lengths, epochs of disturbed and even ceased surface activity, and strong short-term hemispherical asymmetries. Surprisingly, the most prominent suppressed surface activity epoch is actually a global magnetic energy maximum; during this epoch the bottom toroidal magnetic field obtains a maximum, demonstrating that the interpretation of grand minima-type events is non-trivial. The hemispherical asymmetries are seen only in the magnetic field, while the velocity field exhibits considerably weaker asymmetry. Conclusions: We interpret

  15. What is Local Mode (LM)? Global Mode (GM)? Calibration Mode?

    Atmospheric Science Data Center

    2014-12-08

    ... measurement in Global Mode (GM), Local Mode (LM), and Calibration. Global Mode is the normal acquisition with pole to pole coverage ... targets approximately 300 km in length Calibration Implemented bi-monthly Spectralon solar ...

  16. Impact of physical activity on ovarian reserve markers in normal, overweight and obese reproductive age women.

    PubMed

    Surekha, T; Himabindu, Y; Sriharibabu, M; Pandey, Anil Kumar

    2014-01-01

    Physical inactivity is a leading risk factor for overweight and obesity in the society. Prevalence of overweight and obesity in the reproductive age group women not only affects maternal health but also the health of the off spring. Infertility is a common problem in India affecting 13-19 million people at any given time. Even though it is not life threatening, infertility causes intense mental agony and trauma that can only be best described by infertile couples themselves. Infertility is more common in overweight and obese individuals compared to normal weight individuals. Decreasing ovarian reserve is an important factor for infertility in women. This study examined the impact of physical activity on ovarian reserve markers in normal, overweight and obese reproductive age women. The observations made in this study reveal that physical activity improves ovarian reserve markers in all reproductive age women but this improvement is more distinct and statistically significant in overweight and obese women compared to normal weight women. PMID:25509968

  17. Active low-angle (?) normal faulting along the North Lunggar rift, western Tibet

    NASA Astrophysics Data System (ADS)

    Logan, M. A.; Taylor, M. H.; Styron, R. H.; Gosse, J. C.; Ding, L.; Yang, G.

    2012-12-01

    Here we present surface exposure ages of faulted fluvial terraces using cosmogenic nuclides from the North Lunggar rift. The Lunggar rift is one of seven major north-striking rift basins accommodating east-west directed extension on the Tibetan Plateau. The Lunggar rift in west-central Tibet is divided into two distinct north and south segments based on fault geometry. The North Lunggar range is bounded on its east side by a <40 degree dipping, ~N-striking normal fault. This normal fault is considered inactive as the main detachment is unconformably overlain by unfaulted moraines and alluvial fans. Farther into the hanging wall basin, approximately 6 km eastward, several fault scarps parallel the Lunggar detachment. Locally, active faulting is distributed in the hanging wall with as many as seven normal fault scarps accommodating active east-west directed extension. Recent activity of these smaller faults is apparent from cross-cut fluvial terraces that have been uplifted by as much as 75 m. The geomorphology and fault geometry of the North Lunggar rift are consistent with high-angle normal faults that sole into a single master detachment fault at depth. A high-resolution digital elevation model constructed from real-time kinematic-GPS data has made details of the geomorphology clear and allowed for precise measurements of geomorphic offsets across the fault scarps. We estimate the surface abandonment ages using the depth profiling approach with cosmogenic nuclides. Three cosmogenic depth profiles are being analyzed in this study with each depth profile consisting of five samples at varying depths in order to account for inheritance. Site 1 is the southernmost and is on the highest uplifted fluvial terrace and is being prepared for 10Be analysis. Site 2 comprises two depth profiles on the highest and intermediate uplifted terraces, respectively. Samples at site 2 have low quartz yields and are being prepared for 36Cl analysis. Combining the fault offsets and

  18. Evaluation of coupling terms between intra- and intermolecular vibrations in coarse-grained normal-mode analysis: does a stronger acid make a stiffer hydrogen bond?

    PubMed

    Houjou, Hirohiko

    2011-10-21

    Using theory of harmonic normal-mode vibration analysis, we developed a procedure for evaluating the anisotropic stiffness of intermolecular forces. Our scheme for coarse-graining of molecular motions is modified so as to account for intramolecular vibrations in addition to relative translational/rotational displacement. We applied this new analytical scheme to four carboxylic acid dimers, for which coupling between intra- and intermolecular vibrations is crucial for determining the apparent stiffness of the intermolecular double hydrogen bond. The apparent stiffness constant was analyzed on the basis of a conjunct spring model, which defines contributions from true intermolecular stiffness and molecular internal stiffness. Consequently, the true intermolecular stiffness was in the range of 43-48 N m(-1) for all carboxylic acids studied, regardless of the molecules' acidity. We concluded that the difference in the apparent stiffness can be attributed to differences in the internal stiffness of the respective molecules.

  19. Molecular structure, natural bond analysis, vibrational and electronic spectra, surface enhanced Raman scattering and Mulliken atomic charges of the normal modes of [Mn(DDTC)2] complex.

    PubMed

    Téllez S, Claudio A; Costa, Anilton C; Mondragón, M A; Ferreira, Glaucio B; Versiane, O; Rangel, J L; Lima, G Müller; Martin, A A

    2016-12-01

    Theoretical and experimental bands have been assigned for the Fourier Transform Infrared and Raman spectra of the bis(diethyldithiocarbamate)Mn(II) complex, [Mn(DDTC)2]. The calculations have been based on the DFT/B3LYP method, second derivative spectra and band deconvolution analysis. The UV-vis experimental spectra were measured in acetonitrile solution, and the calculated electronic spectrum was obtained using the TD/B3LYP method with 6-311G(d, p) basis set for all atoms. Charge transfer bands and those d-d spin forbidden were assigned in the UV-vis spectrum. The natural bond orbital analysis was carried out using the DFT/B3LYP method and the Mn(II) hybridization leading to the planar geometry of the framework was discussed. Surface enhanced Raman scattering (SERS) was also performed. Mulliken charges of the normal modes were obtained and related to the SERS enhanced bands. PMID:27344520

  20. Molecular structure, natural bond analysis, vibrational and electronic spectra, surface enhanced Raman scattering and Mulliken atomic charges of the normal modes of [Mn(DDTC)2] complex.

    PubMed

    Téllez S, Claudio A; Costa, Anilton C; Mondragón, M A; Ferreira, Glaucio B; Versiane, O; Rangel, J L; Lima, G Müller; Martin, A A

    2016-12-01

    Theoretical and experimental bands have been assigned for the Fourier Transform Infrared and Raman spectra of the bis(diethyldithiocarbamate)Mn(II) complex, [Mn(DDTC)2]. The calculations have been based on the DFT/B3LYP method, second derivative spectra and band deconvolution analysis. The UV-vis experimental spectra were measured in acetonitrile solution, and the calculated electronic spectrum was obtained using the TD/B3LYP method with 6-311G(d, p) basis set for all atoms. Charge transfer bands and those d-d spin forbidden were assigned in the UV-vis spectrum. The natural bond orbital analysis was carried out using the DFT/B3LYP method and the Mn(II) hybridization leading to the planar geometry of the framework was discussed. Surface enhanced Raman scattering (SERS) was also performed. Mulliken charges of the normal modes were obtained and related to the SERS enhanced bands.

  1. Novel mutations in dihydrolipoamide dehydrogenase deficiency in two cousins with borderline-normal PDH complex activity.

    PubMed

    Cameron, Jessie M; Levandovskiy, Valeriy; Mackay, Neviana; Raiman, Julian; Renaud, Deborah L; Clarke, Joe T R; Feigenbaum, Annette; Elpeleg, Orly; Robinson, Brian H

    2006-07-15

    We have diagnosed dihydrolipoamide dehydrogenase (DLD) deficiency in two male second cousins, who presented with markedly different clinical phenotypes. Patient 1 had a recurrent encephalopathy, and patient 2 had microcephaly and lactic acidosis. Their presentation is unusual, in that the DLD subunit deficiency had little effect on pyruvate dehydrogenase complex activity, but caused a severe reduction in the activities of other enzymes that utilize this subunit. We have identified two mutations in the DLD gene in each patient. The second cousins have one novel mutation in common resulting in a substitution of isoleucine for threonine (I47T), which has not been previously reported in the literature. Patient 1 has a second mutation that has been reported to be common in the Ashkenazi Jewish population, G229C. Patient 2 has a second mutation, E375K, which has also been previously reported in the literature. Enzyme kinetic measurements on patient fibroblasts show that under certain conditions, one heteroallelic mutation may have a higher K(m). This may account for the differing clinical phenotypes. These findings have important repercussions for other patients with similar clinical phenotypes, as DLD activity is not normally measured in cases with normal PDHc activity.

  2. Patterns of brain activity in normals and schizophrenics with positron emission tomography

    SciTech Connect

    Volkow, N.D.; Wolf, A.P.; Gomez-Mont, F.; Brodie, J.D.; Canero, R.; Van Gelder, P.; Russell, J.A.G.

    1985-05-01

    The authors investigated the functional interaction among brain areas under baseline and upon activation by a visual task to compare the response of normal subjects from the ones of chronic schizophrenics. Cerebral metabolic images were obtained on twelve healthy volunteers an eighteen schizophrenics with positron emission tomography and 11-C-Deoxyglucose. Correlation coefficients among the relative metabolic values (region of interest divided by the average of whole brain gray matter) of 11 brain regions; frontal, parietal, temporal and occipital left and right lobes, left and right basal ganglia and thalamus were computed for the baseline and for the task. Under baseline, normals showed more functional correlations than schizophrenics. Both groups showed a thalamo-occipital (positive) and thalamo-frontal (negative) interaction. The highest correlations among homologous brain areas were the frontal, occipital and basal ganglia.

  3. Generation of picosecond pulses and frequency combs in actively mode locked external ring cavity quantum cascade lasers

    SciTech Connect

    Wójcik, Aleksander K.; Belyanin, Alexey; Malara, Pietro; Blanchard, Romain; Mansuripur, Tobias S.; Capasso, Federico

    2013-12-02

    We propose a robust and reliable method of active mode locking of mid-infrared quantum cascade lasers and develop its theoretical description. Its key element is the use of an external ring cavity, which circumvents fundamental issues undermining the stability of mode locking in quantum cascade lasers. We show that active mode locking can give rise to the generation of picosecond pulses and phase-locked frequency combs containing thousands of the ring cavity modes.

  4. Dual resin cement knoop hardness after different activation modes through dental ceramics.

    PubMed

    Valentino, Thiago Assunção; Borges, Gilberto Antonio; Borges, Luis Henrique; Vishal, Jain; Martins, Luis Roberto Marcondes; Correr-Sobrinho, Lourenço

    2010-01-01

    This study investigated the influence of ceramic compositions on Knoop Hardness Number (KHN) immediately and 24 h after polymerization and the effect of activation modes on the KHN of a resin cement. Ten Panavia F 2.0 resin cement discs were activated either directly using curing light, or chemically without light, or through 1.2-thick ceramic discs. The following ceramics were evaluated: Duceram, Cergogold, IPS Empress, IPS Empress 2, Procera, Cercon, In Ceram Alumina and In Ceram Zirconia. The KHN was obtained immediately and after 24-h testing time. Two-way ANOVA and Tukey's test were performed for statistical analysis (p<0.05). Direct activation showed higher KHN than activation through ceramics and chemical activation for both immediate and 24-h post activation. The KHN for 24-h post activation time was higher than that of the immediate post activation time except for the direct activation mode. The glass and di-silicate based ceramics showed higher KHN than alumina- and zirconia-based ceramics, immediately and after 24-h. The reinforced and opaque ceramics had the lowest KHN. The ceramic composition resulted in light attenuation, lower polymerization and lower KHN, and the 24-h testing time promoted an improvement of KHN except for direct activation mode.

  5. Experimental Investigation of Wavelength-Tunable All-Normal-Dispersion Yb-Doped Mode-Locked Fiber Lasers: Compression and Amplification

    NASA Astrophysics Data System (ADS)

    Xiao, Xiao-Sheng; Hua, Yi

    2015-02-01

    Wavelength-tunable ultrashort pulse source with high energy is highly desired for a lot of applications. The wavelength-tunable all-normal-dispersion (ANDi) mode-locked fiber laser, which can be compressed easily and amplified by an all-fiber structure, is a promising seed of such a source with compact structures. The pulse compression and amplification at different center wavelengths (from 1026 to 1058 nm) of the tunable ANDi Ybdoped mode-locked fiber lasers that we previously proposed are experimentally investigated in this work. It is found that, for different wavelengths, the duration and chirp of the direct output pulse from the oscillator vary considerably, however, the duration of compressed pulse fluctuates less. For the amplification process, due to the unflat gain spectrum of Yb-doped fiber, the gain at a short wavelength is larger than that at a long wavelength. Consequently, the trends of spectrum distortions induced by the amplification process are different for different wavelengths. These results and analyses will be helpful for the design of a high-energy and wavelength-tunable ultrashort pulse source based on an ANDi seed.

  6. Supercontinuum generation based on all-normal-dispersion Yb-doped fiber laser mode-locked by nonlinear polarization rotation: Influence of seed's output port

    NASA Astrophysics Data System (ADS)

    Xiao, Xiaosheng; Hua, Yi

    2016-10-01

    All-normal-dispersion (ANDi) mode-locked Yb-doped fiber laser is a promising seed source for supercontinuum (SC) generation, due to its compact structure and broadband output. The influences of output ports of the ANDi laser mode-locked by nonlinear polarization rotation (NPR), on the generated SC are investigated. Two output ports of ANDi laser are considered, one of which is the conventional nonlinear polarization rotation (NPR) port and the other is extracted from a coupler after the NPR port. It is found that, the SC originated from the coupler port is much broader than that from the NPR port, which is validated by lots of experiments with different output parameters. Furthermore, the conclusion is verified and generalized to general ANDi lasers by numerical simulations, because the output pulse from coupler port could be cleaner than that from NPR port. Besides, there are no significant differences in the phase coherence and temporal stability between the SCs generated from both ports. Hence for the SC generation based on ANDi laser, it is preferred to use the pulse of coupler port (i.e. pulse after NPR port) serving as the seed source.

  7. Active normal faulting along the Mt. Morrone south-western slopes (central Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Gori, Stefano; Giaccio, Biagio; Galadini, Fabrizio; Falcucci, Emanuela; Messina, Paolo; Sposato, Andrea; Dramis, Francesco

    2011-01-01

    In the present work we analyse one of the active normal faults affecting the central Apennines, i.e. the Mt. Morrone normal fault system. This tectonic structure, which comprises two parallel, NW-SE trending fault segments, is considered as potentially responsible for earthquakes of magnitude ≥ 6.5 and its last activation probably occurred during the second century AD. Structural observations performed along the fault planes have allowed to define the mainly normal kinematics of the tectonic structure, fitting an approximately N 20° trending extensional deformation. Geological and geomorphological investigations performed along the whole Mt. Morrone south-western slopes permitted us to identify the displacement of alluvial fans, attributed to Middle and Late Pleistocene by means of tephro-stratigraphic analyses and geomorphological correlations with dated lacustrine sequences, along the western fault branch. This allowed to evaluate in 0.4 ± 0.07 mm/year the slip rate of this segment. On the other hand, the lack of synchronous landforms and/or deposits that can be correlated across the eastern fault segment prevented the definition of the slip rate related to this fault branch. Nevertheless, basing on a critical review of the available literature dealing with normal fault systems evolution, we hypothesised a total slip rate of the fault system in the range of 0.4 ± 0.07 to 0.8 ± 0.09 mm/year. Moreover, basing on the length at surface of the Mt. Morrone fault system (i.e. 22-23 km) we estimated the maximum expected magnitude of an earthquake that might originate along this tectonic structure in the order of 6.6-6.7.

  8. Numerical simulation of coastal flooding after potential reactivation of an active normal fault in northern Taiwan

    NASA Astrophysics Data System (ADS)

    Chan, Yu-Chang; Kuo, Chih-Yu; Chang, Kuo-Jen; Chen, Rou-Fei; Hsieh, Yu-Chung

    2016-04-01

    Rapid coastal flooding from seawards may be resulted from storm surge, tsunamis, and sudden land subsidence due to fault activities. Many observations and numerical modeling of flooding have been made for cases resulted from storm surge and tsunami events; however, coastal flooding caused by a potential normal faulting event nearby coastal areas is rarely reported. In addition to the earthquake hazards from fault rupturing and ground shaking, the accompanied hazards of earthquake-induced flooding is also important to be investigated. The Jinshan area in northern Taiwan was reported to have been flooded by a tsunami event in the year of 1867 possibly resulted from the reactivation of the Shanchiao normal fault offshore. Historical records have shown that the Shanchiao Fault that extends from Shulin along the western edge of the Taipei Basin to the town of Jinshan may have also ruptured in the year of 1694. The rupturing event has created a depression on the western side of the Taipei Basin that was later filled by sea water called the Taipei Lake. The geological conditions in northern Taiwan provide an opportunity for numerically simulating the dynamic processes of sea water flooding nearby the coastal area immediately after an earthquake-induced normal faulting event. In this study, we focused on the potential active normal faulting that may occur and result in an expected catastrophic flooding in lowland area of Jinshan in northern Taiwan. We applied the continuum shallow water equation to evaluate the unknown inundation processes including location, extent, velocity and water depths after the flooding initiated and the final state of the flooding event. The modeling results were well compared with borehole observations of the extent of previous flooding events possibly due to tsunami events. In addition, the modeling results may provide a future basis for safety evaluation of the two nuclear power plants nearby the region.

  9. Insulin secretion enhancing activity of roselle calyx extract in normal and streptozotocin-induced diabetic rats

    PubMed Central

    Wisetmuen, Eamruthai; Pannangpetch, Patchareewan; Kongyingyoes, Bunkerd; Kukongviriyapan, Upa; Yutanawiboonchai, Wiboonchai; Itharat, Arunporn

    2013-01-01

    Background and Objective: Our recent study revealed the antihyperglycemic activity of an ethanolic extract of roselle calyxes (Hibiscus sabdariffa) in diabetic rats. The present study had, therefore, an objective to investigate the mechanism underlying this activity. Materials and Methods: Male Sprague Dawley rats were induced to be diabetes by intraperitoneal injection of 45 mg/kg streptozotocin (STZ). Normal rats as well as diabetic rats were administered with the ethanolic extract of H. sabdariffa calyxes (HS-EE) at 0.1 and 1.0 g/kg/day, respectively, for 6 weeks. Then, blood glucose and insulin levels, at basal and glucose-stimulated secretions, were measured. The pancreas was dissected to examine histologically. Results: HS-EE 1.0 g/kg/day significantly decreased the blood glucose level by 38 ± 12% in diabetic rats but not in normal rats. In normal rats, treatment with 1.0 g/kg HS-EE increased the basal insulin level significantly as compared with control normal rats (1.28 ± 0.25 and 0.55 ± 0.05 ng/ml, respectively). Interestingly, diabetic rats treated with 1.0 g/kg HS-EE also showed a significant increase in basal insulin level as compared with the control diabetic rats (0.30 ± 0.05 and 0.15 ± 0.01 ng/ml, respectively). Concerning microscopic histological examination, HS-EE 1.0 g/kg significantly increased the number of islets of Langerhans in both normal rats (1.2 ± 0.1 and 2.0 ± 0.1 islet number/10 low-power fields (LPF) for control and HS-EE treated group, respectively) and diabetic rats (1.0 ± 0.3 and 3.9 ± 0.6 islet number/10 LPF for control and HS-EE treated group, respectively). Conclusion: The antidiabetic activity of HS-EE may be partially mediated via the stimulating effect on insulin secretion. PMID:23798879

  10. Anatomically realistic multiscale models of normal and abnormal gastrointestinal electrical activity

    PubMed Central

    Cheng, Leo K; Komuro, Rie; Austin, Travis M; Buist, Martin L; Pullan, Andrew J

    2007-01-01

    One of the major aims of the International Union of Physiological Sciences (IUPS) Physiome Project is to develop multiscale mathematical and computer models that can be used to help understand human health. We present here a small facet of this broad plan that applies to the gastrointestinal system. Specifically, we present an anatomically and physiologically based modelling framework that is capable of simulating normal and pathological electrical activity within the stomach and small intestine. The continuum models used within this framework have been created using anatomical information derived from common medical imaging modalities and data from the Visible Human Project. These models explicitly incorporate the various smooth muscle layers and networks of interstitial cells of Cajal (ICC) that are known to exist within the walls of the stomach and small bowel. Electrical activity within individual ICCs and smooth muscle cells is simulated using a previously published simplified representation of the cell level electrical activity. This simulated cell level activity is incorporated into a bidomain representation of the tissue, allowing electrical activity of the entire stomach or intestine to be simulated in the anatomically derived models. This electrical modelling framework successfully replicates many of the qualitative features of the slow wave activity within the stomach and intestine and has also been used to investigate activity associated with functional uncoupling of the stomach. PMID:17457969

  11. Anatomically realistic multiscale models of normal and abnormal gastrointestinal electrical activity.

    PubMed

    Cheng, Leo K; Komuro, Rie; Austin, Travis M; Buist, Martin L; Pullan, Andrew J

    2007-03-01

    One of the major aims of the International Union of Physiological Sciences (IUPS) Physiome Project is to develop multiscale mathematical and computer models that can be used to help understand human health. We present here a small facet of this broad plan that applies to the gastrointestinal system. Specifically, we present an anatomically and physiologically based modelling framework that is capable of simulating normal and pathological electrical activity within the stomach and small intestine. The continuum models used within this framework have been created using anatomical information derived from common medical imaging modalities and data from the Visible Human Project. These models explicitly incorporate the various smooth muscle layers and networks of interstitial cells of Cajal (ICC) that are known to exist within the walls of the stomach and small bowel. Electrical activity within individual ICCs and smooth muscle cells is simulated using a previously published simplified representation of the cell level electrical activity. This simulated cell level activity is incorporated into a bidomain representation of the tissue, allowing electrical activity of the entire stomach or intestine to be simulated in the anatomically derived models. This electrical modelling framework successfully replicates many of the qualitative features of the slow wave activity within the stomach and intestine and has also been used to investigate activity associated with functional uncoupling of the stomach.

  12. Crystal structure of plasminogen activator inhibitor-1 in an active conformation with normal thermodynamic stability.

    PubMed

    Jensen, Jan K; Thompson, Lawrence C; Bucci, Joel C; Nissen, Poul; Gettins, Peter G W; Peterson, Cynthia B; Andreasen, Peter A; Morth, J Preben

    2011-08-26

    The serpin plasminogen activator inhibitor-1 (PAI-1) is a crucial regulator in fibrinolysis and tissue remodeling. PAI-1 has been associated with several pathological conditions and is a validated prognostic marker in human cancers. However, structural information about the native inhibitory form of PAI-1 has been elusive because of its inherent conformational instability and rapid conversion to a latent, inactive structure. Here we report the crystal structure of PAI-1 W175F at 2.3 Å resolution as the first model of the metastable native molecule. Structural comparison with a quadruple mutant (14-1B) previously used as representative of the active state uncovered key differences. The most striking differences occur near the region that houses three of the four mutations in the 14-1B PAI-1 structure. Prominent changes are localized within a loop connecting β-strand 3A with the F helix, in which a previously observed 3(10)-helix is absent in the new structure. Notably these structural changes are found near the binding site for the cofactor vitronectin. Because vitronectin is the only known physiological regulator of PAI-1 that slows down the latency conversion, the structure of this region is important. Furthermore, the previously identified chloride-binding site close to the F-helix is absent from the present structure and likely to be artifactual, because of its dependence on the 14-1B mutations. Instead we found a different chlorine-binding site that is likely to be present in wild type PAI-1 and that more satisfactorily accounts for the chlorine stabilizing effect on PAI-1.

  13. Crystal Structure of Plasminogen Activator Inhibitor-1 in an Active Conformation with Normal Thermodynamic Stability*

    PubMed Central

    Jensen, Jan K.; Thompson, Lawrence C.; Bucci, Joel C.; Nissen, Poul; Gettins, Peter G. W.; Peterson, Cynthia B.; Andreasen, Peter A.; Morth, J. Preben

    2011-01-01

    The serpin plasminogen activator inhibitor-1 (PAI-1) is a crucial regulator in fibrinolysis and tissue remodeling. PAI-1 has been associated with several pathological conditions and is a validated prognostic marker in human cancers. However, structural information about the native inhibitory form of PAI-1 has been elusive because of its inherent conformational instability and rapid conversion to a latent, inactive structure. Here we report the crystal structure of PAI-1 W175F at 2.3 Å resolution as the first model of the metastable native molecule. Structural comparison with a quadruple mutant (14-1B) previously used as representative of the active state uncovered key differences. The most striking differences occur near the region that houses three of the four mutations in the 14-1B PAI-1 structure. Prominent changes are localized within a loop connecting β-strand 3A with the F helix, in which a previously observed 310-helix is absent in the new structure. Notably these structural changes are found near the binding site for the cofactor vitronectin. Because vitronectin is the only known physiological regulator of PAI-1 that slows down the latency conversion, the structure of this region is important. Furthermore, the previously identified chloride-binding site close to the F-helix is absent from the present structure and likely to be artifactual, because of its dependence on the 14-1B mutations. Instead we found a different chlorine-binding site that is likely to be present in wild type PAI-1 and that more satisfactorily accounts for the chlorine stabilizing effect on PAI-1. PMID:21697084

  14. Characterization and analysis of timing jitter in normal-dispersion mode-locked Er-fiber lasers with intra-cavity filtering.

    PubMed

    Shin, Junho; Jung, Kwangyun; Song, Youjian; Kim, Jungwon

    2015-08-24

    We characterize and analyze the timing jitter of normal-dispersion mode-locked Er-fiber lasers with intra-cavity filtering. The timing jitter of Er-fiber lasers with 9-nm bandpass filters operating at + 0.0084 ps(2) is measured to be 3.46 fs (rms) when integrated from 10 kHz to 10 MHz offset frequency, which is similar to the jitter level of typical stretched-pulse or soliton Er-fiber lasers. The numerical simulation based on split-step Fourier transform method shows that the measured high-frequency jitter is quantum noise-limited performance. We also develop an analytical model for filtered normal-dispersion fiber lasers by modifying the well-established noise model of stretched-pulse fiber lasers. The analytical modeling reveals that the jitter performance is improved mostly by reducing the chirp parameter by intra-cavity filtering. Both numerical simulation and analytical model fit fairly well with the measured timing jitter result.

  15. Influence of sleep on genioglossus muscle activation by negative pressure in normal men.

    PubMed

    Wheatley, J R; Mezzanotte, W S; Tangel, D J; White, D P

    1993-09-01

    An important mechanism controlling genioglossus (GG) muscle activity is the reflex response to negative airway pressure. We hypothesize that this reflex response may be lost during sleep and believe that this loss may be important in the pathogenesis of airway collapse during sleep. Thus, we determined the effect of non-rapid eye movement (NREM) sleep on the GG electromyogram (EMG) response to brief (0.2 to 0.6 s) episodes of negative pressure generation (NPG) in the upper airway of six normal subjects. Up to 100 NPGs (mean 58 +/- 12) were recorded both awake and during stable NREM sleep. During wakefulness, the change in GG moving time average EMG from basal to peak levels (during NPG) was 17.1 +/- 2.5 au (a 154 +/- 22% increase above basal levels). This response was markedly reduced during NREM sleep (2.7 +/- 1.2 au; p < 0.01). The latency of the GG EMG response was 53.8 +/- 11.5 ms during wakefulness (n = 6), but much longer during sleep (132.7 +/- 24.5 ms; n = 3; p < 0.03). We conclude that in normal subjects (1) the GG muscle responds to negative airway pressure by reflex activation during wakefulness, and (2) this reflex activation is reduced or lost during NREM sleep. We speculate that loss of this mechanism during sleep may contribute to pharyngeal collapse in obstructive apnea patients.

  16. Activation of mechanosensitive ion channel TRPV4 normalizes tumor vasculature and improves cancer therapy

    PubMed Central

    Adapala, Ravi K.; Thoppil, Roslin J.; Ghosh, Kaustabh; Cappelli, Holly; Dudley, Andrew C.; Paruchuri, Sailaja; Keshamouni, Venkateshwar; Klagsbrun, Michael; Meszaros, J. Gary; Chilian, William M.; Ingber, Donald E.; Thodeti, Charles K.

    2016-01-01

    Tumor vessels are characterized by abnormal morphology and hyper-permeability that together cause inefficient delivery of chemotherapeutic agents. Although VEGF has been established as a critical regulator of tumor angiogenesis, the role of mechanical signaling in the regulation of tumor vasculature or tumor endothelial cell (TEC) function is not known. Here, we show that the mechanosensitive ion channel TRPV4 regulates tumor angiogenesis and tumor vessel maturation via modulation of TEC mechanosensitivity. We found that TEC exhibit reduced TRPV4 expression and function, which is correlated with aberrant mechanosensitivity towards ECM stiffness, increased migration and abnormal angiogenesis by TEC. Further, syngeneic tumor experiments revealed that the absence of TRPV4 induced increased vascular density, vessel diameter and reduced pericyte coverage resulting in enhanced tumor growth in TRPV4 KO mice. Importantly, overexpression or pharmacological activation of TRPV4 restored aberrant TEC mechanosensitivity, migration and normalized abnormal angiogenesis in vitro by modulating Rho activity. Finally, a small molecule activator of TRPV4, GSK1016790A, in combination with anti-cancer drug Cisplatin, significantly reduced tumor growth in WT mice by inducing vessel maturation. Our findings demonstrate TRPV4 channels to be critical regulators of tumor angiogenesis and represent a novel target for anti-angiogenic and vascular normalization therapies. PMID:25867067

  17. VizieR Online Data Catalog: Star formation in active and normal galaxies (Tsai+, 2015)

    NASA Astrophysics Data System (ADS)

    Tsai, M.; Hwang, C.-Y.

    2015-11-01

    We selected 104 active galaxies from the lists of Melendez et al. (2010MNRAS.406..493M), Condon et al. 1991 (cat. J/ApJ/378/65), and Ho & Ulvestad 2001 (cat. J/ApJS/133/77). Most of the sources are identified as Active Galactic Nuclei (AGNs), and a few of them are classified as Luminous InfraRed Galaxies (LIRGs). We obtained 3.6 and 8μm infrared images of these galaxies from the Spitzer Archive (http://sha.ipac.caltech.edu/applications/Spitzer/SHA/) and 8GHz images from the VLA archive (http://archive.nrao.edu/archive/archiveimage.html). We also selected a nearby AGN sub-sample containing 21 radio-selected AGNs for further spatial analysis. We selected 25 nearby AGNs exhibiting no detected radio emission in order to compare with the results of the radio-selected sources. For comparison, we also selected normal galaxies with distances less than 15Mpc from the catalog of Tully 1994 (see cat. VII/145). We only selected the galaxies that have Spitzer archive data and are not identified as AGNs in either the Veron-Cetty & Veron 2006 (see cat. VII/258) AGN catalog or in the NED database (http://ned.ipac.caltech.edu/). Our results for the radio-selected and the non-radio-selected active galaxies are listed in Table1, and those for the normal galaxies are listed in Table2. (2 data files).

  18. Predicting above normal wildfire activity in southern Europe as a function of meteorological drought

    NASA Astrophysics Data System (ADS)

    Gudmundsson, L.; Rego, F. C.; Rocha, M.; Seneviratne, S. I.

    2014-08-01

    Wildfires are a recurrent feature of ecosystems in southern Europe, regularly causing large ecological and socio-economic damages. For efficient management of this hazard, long lead time forecasts could be valuable tools. Using logistic regression, we show that the probability of above normal summer wildfire activity in the 1985-2010 time period can be forecasted as a function of meteorological drought with significant predictability (p \\lt 0.05) several months in advance. The results show that long lead time forecasts of this natural hazard are feasible in southern Europe, which could potentially aid decision-makers in the design of strategies for forest management.

  19. Modulation of activation-loop phosphorylation by JAK inhibitors is binding mode dependent

    PubMed Central

    Bonenfant, Débora; Rubert, Joëlle; Vangrevelinghe, Eric; Scheufler, Clemens; Marque, Fanny; Régnier, Catherine H.; De Pover, Alain; Ryckelynck, Hugues; Bhagwat, Neha; Koppikar, Priya; Goel, Aviva; Wyder, Lorenza; Tavares, Gisele; Baffert, Fabienne; Pissot-Soldermann, Carole; Manley, Paul W.; Gaul, Christoph; Voshol, Hans; Levine, Ross L.; Sellers, William R.; Hofmann, Francesco; Radimerski, Thomas

    2016-01-01

    JAK inhibitors are being developed for the treatment of rheumatoid arthritis, psoriasis, myeloproliferative neoplasms and leukemias. Most of these drugs target the ATP-binding pocket and stabilize the active conformation of the JAK kinases. This type-I binding mode leads to an increase in JAK activation-loop phosphorylation, despite blockade of kinase function. Here we report that stabilizing the inactive state via type-II inhibition acts in the opposite manner, leading to a loss of activation-loop phosphorylation. We used X-ray crystallography to corroborate the binding mode and report for the first time the crystal structure of the JAK2 kinase domain in an inactive conformation. Importantly, JAK inhibitor-induced activation-loop phosphorylation requires receptor interaction, as well as intact kinase and pseudokinase domains. Hence, depending on the respective conformation stabilized by a JAK inhibitor, hyperphosphorylation of the activation-loop may or may not be elicited. PMID:22684457

  20. Normal coordinate analysis and fungicidal activity study on anilazine and its related compound using spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Sheeja Mol, Gilbert Pushpam; Arul Dhas, Deva Dhas; Hubert Joe, Isaac; Balachandran, Sreedharan

    2016-06-01

    The FTIR and FT-Raman spectra of anilazine have been recorded in the range 400-4000 cm-1 and 50-3500 cm-1 respectively. The optimized geometrical parameters of the compound were calculated using B3LYP method with 6-311G(d,p) basis set. The distribution of the vibrational bands were carried out with the help of normal coordinate analysis (NCA). The 1H and 13C nuclear spectra have been recorded and chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. The UV-Visible spectrum of the compound was recorded in the region 190-900 nm and the electronic properties were determined by time-dependent DFT (TD-DFT) approach. Anilazine was screened for its antifungal activity. Molecular docking studies are conducted to predict its fungicidal activity.

  1. Beta activity in the premotor cortex is increased during stabilized as compared to normal walking

    PubMed Central

    Bruijn, Sjoerd M.; Van Dieën, Jaap H.; Daffertshofer, Andreas

    2015-01-01

    Walking on two legs is inherently unstable. Still, we humans perform remarkable well at it, mostly without falling. To gain more understanding of the role of the brain in controlling gait stability we measured brain activity using electro-encephalography (EEG) during stabilized and normal walking. Subjects walked on a treadmill in two conditions, each lasting 10 min; normal, and while being laterally stabilized by elastic cords. Kinematics of trunk and feet, electro-myography (EMG) of neck muscles, as well as 64-channel EEG were recorded. To assess gait stability the local divergence exponent, step width, and trunk range of motion were calculated from the kinematic data. We used independent component (IC) analysis to remove movement, EMG, and eyeblink artifacts from the EEG, after which dynamic imaging of coherent sources beamformers were determined to identify cortical sources that showed a significant difference between conditions. Stabilized walking led to a significant increase in gait stability, i.e., lower local divergence exponents. Beamforming analysis of the beta band activity revealed significant sources in bilateral pre-motor cortices. Projection of sensor data on these sources showed a significant difference only in the left premotor area, with higher beta power during stabilized walking, specifically around push-off, although only significant around contralateral push-off. It appears that even during steady gait the cortex is involved in the control of stability. PMID:26578937

  2. X-mode reflectometry for magnetohydrodynamic activity associated with q=1 surface measurements on Tore Supra

    SciTech Connect

    Vermare, L.; Clairet, F.; Gabillet, F.; Sabot, R.; Sirinelli, A.; Heuraux, S.; Leclert, G.

    2004-10-01

    Tore Supra is equipped with two 20 {mu}s fast sweep X-mode reflectometers operating between 50-110 GHz dedicated to density profile determination and an X-mode fixed frequency reflectometer operating between 105-155 GHz for density fluctuation measurements. Heterodyne and sine-cosine detection provide measurements of the reflected signal with high sensitivity. Operating profile reflectometer in burst mode (5 {mu}s dead time between two consecutive sweeps) allows quasi-simultaneous measurements at fixed frequency over a broad frequency band. Thus, information on plasma fluctuations, such as magnetohydrodynamic (MHD) activity, up to 20 kHz as well as a radial localization of the modes is accessible. The temporal evolution of the q=1 rational surface during sawtooth crash activity has been recorded in the plasma center with high spatial resolution. In addition, a direct comparison between signals associated with a central MHD mode from both profile and fluctuation reflectometers, positioned at different toroidal angles, allows one to determine the plasma toroidal velocity.

  3. Effect of norfloxacin and moxifloxacin on melanin synthesis and antioxidant enzymes activity in normal human melanocytes.

    PubMed

    Beberok, Artur; Wrześniok, Dorota; Otręba, Michał; Miliński, Maciej; Rok, Jakub; Buszman, Ewa

    2015-03-01

    Fluoroquinolone antibiotics provide broad-spectrum coverage for a number of infectious diseases, including respiratory as well as urinary tract infections. One of the important adverse effects of these drugs is phototoxicity which introduces a serious limitation to their use. To gain insight the molecular mechanisms underlying the fluoroquinolones-induced phototoxic side effects, the impact of two fluoroquinolone derivatives with different phototoxic potential, norfloxacin and moxifloxacin, on melanogenesis and antioxidant enzymes activity in normal human melanocytes HEMa-LP was determined. Both drugs induced concentration-dependent loss in melanocytes viability. The value of EC50 for these drugs was found to be 0.5 mM. Norfloxacin and moxifloxacin suppressed melanin biosynthesis; antibiotics were shown to inhibit cellular tyrosinase activity and to reduce melanin content in melanocytes. When comparing the both analyzed fluoroquinolones, it was observed that norfloxacin possesses greater inhibitory effect on tyrosinase activity in melanocytes than moxifloxacin. The extent of oxidative stress in cells was assessed by measuring the activity of antioxidant enzymes: SOD, CAT, and GPx. It was observed that norfloxacin caused higher depletion of antioxidant status in melanocytes when compared with moxifloxacin. The obtained results give a new insight into the mechanisms of fluoroquinolones toxicity directed to pigmented tissues. Moreover, the presented differences in modulation of biochemical processes in melanocytes may be an explanation for various phototoxic activities of the analyzed fluoroquinolone derivatives in vivo.

  4. Long-term facilitation of genioglossus activity is present in normal humans during NREM sleep

    PubMed Central

    Chowdhuri, Susmita; Pierchala, Lisa; Aboubakr, Salah E.; Shkoukani, Mahdi; Badr, M. Safwan

    2008-01-01

    Episodic hypoxia (EH) is followed by increased ventilatory motor output in the recovery period indicative of long-term facilitation (LTF). We hypothesized that episodic hypoxia evokes LTF of genioglossus (GG) muscle activity in humans during non-rapid eye movement sleep (NREM) sleep. We studied 12 normal non-flow limited humans during stable NREM sleep. We induced 10 brief (3 minute) episodes of isocapnic hypoxia followed by 5 minutes of room air. Measurements were obtained during control, hypoxia, and at 5, 10, 20, 30 and 40 minutes of recovery, respectively, for minute ventilation (V̇I), supraglottic pressure (PSG), upper airway resistance (RUA) and phasic GG electromyogram (EMGGG). In addition, sham studies were conducted on room air. During hypoxia there was a significant increase in phasic EMGGG (202.7±24.1% of control, p<0.01) and in V̇I (123.0±3.3% of control, p<0.05); however, only phasic EMGGG demonstrated a significant persistent increase throughout recovery (198.9±30.9%, 203.6±29.9% and 205.4±26.4% of control, at 5, 10, and 20 minutes of recovery, respectively, p<0.01). In multivariate regression analysis, age and phasic EMGGG activity during hypoxia were significant predictors of EMGGG at recovery 20 minutes. No significant changes in any of the measured parameters were noted during sham studies. Conclusion: 1) EH elicits LTF of GG in normal non-flow limited humans during NREM sleep, without ventilatory or mechanical LTF. 2) GG activity during the recovery period correlates with the magnitude of GG activation during hypoxia, and inversely with age. PMID:17945544

  5. Different pulse pattern generation by frequency detuning in pulse modulated actively mode-locked ytterbium doped fiber laser

    NASA Astrophysics Data System (ADS)

    Chen, He; Chen, Sheng-Ping; Si, Lei; Zhang, Bin; Jiang, Zong-Fu

    2015-10-01

    We report the results of our recent experimental investigation of the modulation frequency detuning effect on the output pulse dynamics in a pulse modulated actively mode-locked ytterbium doped fiber laser. The experimental study shows the existence of five different mode-locking states that mainly depend on the modulation frequency detuning, which are: (a) amplitude-even harmonic/fundamental mode-locking, (b) Q-switched harmonic/fundamental mode-locking, (c) sinusoidal wave modulation mode, (d) pulses bundle state, and (e) noise-like state. A detailed experimental characterization of the output pulses dynamics in each operating mode is presented.

  6. The hypotensive effect of acute and chronic AMP-activated protein kinase activation in normal and hyperlipidemic mice

    PubMed Central

    Greig, Fiona H.; Ewart, Marie-Ann; McNaughton, Eilidh; Cooney, Josephine; Spickett, Corinne M.; Kennedy, Simon

    2015-01-01

    AMP-activated protein kinase (AMPK) is present in the arterial wall and is activated in response to cellular stressors that raise AMP relative to ADP/ATP. Activation of AMPK in vivo lowers blood pressure but the influence of hyperlipidemia on this response has not been studied. ApoE−/− mice on high fat diet for 6 weeks and age-matched controls were treated with the AMPK activator, AICAR daily for two weeks. Under anesthesia, the carotid artery was cannulated for blood pressure measurements. Aortic tissue was removed for in vitro functional experiments and AMPK activity was measured in artery homogenates by Western blotting. ApoE−/− mice had significantly raised mean arterial pressure; chronic AICAR treatment normalized this but had no effect in normolipidemic mice, whereas acute administration of AICAR lowered mean arterial pressure in both groups. Chronic AICAR treatment increased phosphorylation of AMPK and its downstream target acetyl-CoA carboxylase in normolipidemic but not ApoE−/− mice. In aortic rings, AMPK activation induced vasodilation and an anticontractile effect, which was attenuated in ApoE−/− mice. This study demonstrates that hyperlipidemia dysregulates the AMPK pathway in the arterial wall but this effect can be reversed by AMPK activation, possibly through improving vessel compliance. PMID:26196300

  7. Antiviral activity and mode of action of extracts from neem seed kernel against duck plague virus in vitro1.

    PubMed

    Xu, J; Song, X; Yin, Z Q; Cheng, A C; Jia, R Y; Deng, Y X; Ye, K C; Shi, C F; Lv, C; Zhang, W

    2012-11-01

    Four fractions obtained from alcohol extracts of neem (Azadirachta indica) seed kernel by column chromatography were investigated for antivirus activity against the duck plague virus (DPV) in vitro. Duck embryo fibroblasts (DEF) infected with DPV were treated with the neem seed kernel extracts, and the effect of antivirus was judged by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide colorimetric method assay and direct immunofluorescence assay. The mode of action was tested by the plaque reduction assay. The results showed that fractions 1 to 3 were inactive. The median inhibitory concentration (IC(50)) of fraction 4 was 10.9 μg/mL and inhibited the virus protein expression in the direct immunofluorescence assay. In the plaque reduction assay, fraction 4 could significantly reduce the number of plaques compared with the negative control (P < 0.01) in all modes of action. This study indicated that the fourth fraction obtained from neem seed kernel could improve the viability of infected cells, and reduce the cytopathic effects caused by DPV and the amount of the virus protein expressed in virus-infected cells. The antiviral activity works in the whole process of virus infecting the normal cells. PMID:23091135

  8. Relation between QT interval variability and muscle sympathetic nerve activity in normal subjects.

    PubMed

    El-Hamad, Fatima; Lambert, Elisabeth; Abbott, Derek; Baumert, Mathias

    2015-10-01

    Beat-to-beat variability of the QT interval (QTV) is sought to provide an indirect noninvasive measure of sympathetic nerve activity, but a formal quantification of this relationship has not been provided. In this study we used power contribution analysis to study the relationship between QTV and muscle sympathetic nerve activity (MSNA). ECG and MSNA were recorded in 10 healthy subjects in the supine position and after 40° head-up tilt. Power spectrum analysis was performed using a linear autoregressive model with two external inputs: heart period (RR interval) variability (RRV) and MSNA. Total and low-frequency power of QTV was decomposed into contributions by RRV, MSNA, and sources independent of RRV and MSNA. Results show that the percentage of MSNA power contribution to QT is very small and does not change with tilt. RRV power contribution to QT power is notable and decreases with tilt, while the greatest percentage of QTV is independent of RRV and MSNA in the supine position and after 40° head-up tilt. In conclusion, beat-to-beat QTV in normal subjects does not appear to be significantly affected by the rhythmic modulations in MSNA following low to moderate orthostatic stimulation. Therefore, MSNA oscillations may not represent a useful surrogate for cardiac sympathetic nerve activity at moderate levels of activation, or, alternatively, sympathetic influences on QTV are complex and not quantifiable with linear shift-invariant autoregressive models. PMID:26276814

  9. Active Noise Control of Low Speed Fan Rotor-Stator Modes

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.; Hu, Ziqiang; Pla, Frederic G.; Heidelberg, Laurence J.

    1996-01-01

    This report describes the Active Noise Cancellation System designed by General Electric and tested in the NASA Lewis Research Center's 48 inch Active Noise Control Fan. The goal of this study was to assess the feasibility of using wall mounted secondary acoustic sources and sensors within the duct of a high bypass turbofan aircraft engine for active noise cancellation of fan tones. The control system is based on a modal control approach. A known acoustic mode propagating in the fan duct is cancelled using an array of flush-mounted compact sound sources. Controller inputs are signals from a shaft encoder and a microphone array which senses the residual acoustic mode in the duct. The canceling modal signal is generated by a modal controller. The key results are that the (6,0) mode was completely eliminated at 920 Hz and substantially reduced elsewhere. The total tone power was reduced 9.4 dB. Farfield 2BPF SPL reductions of 13 dB were obtained. The (4,0) and (4,1) modes were reduced simultaneously yielding a 15 dB modal PWL decrease. Global attenuation of PWL was obtained using an actuator and sensor system totally contained within the duct.

  10. Wavelength-tunable actively mode-locked erbium-doped fiber ring laser using a distributed feedback semiconductor laser as mode locker and tunable filter

    NASA Astrophysics Data System (ADS)

    Li, Shenping; Chan, K. T.

    1999-07-01

    A wavelength-tunable actively mode-locked erbium fiber ring laser was demonstrated using a distributed feedback semiconductor laser as an intensity mode locker and a tunable optical filter. Very stable optical pulse trains at gigabit repetition rates were generated using harmonica mode locking. The supermode noise was suppressed to 60 dB below the signal level and the root-mean-square timing jitter (0.45 kHz-1 MHz) was found to be about 1% of the pulse duration. A continuous wavelength tuning range of 1.8 nm was achieved by changing the semiconductor laser temperature from 11.4 to 30 °C.

  11. Molecular Structures, Vibrational Spectroscopy, and Normal-Mode Analysis of M(2)(C&tbd1;CR)(4)(PMe(3))(4) Dimetallatetraynes. Observation of Strongly Mixed Metal-Metal and Metal-Ligand Vibrational Modes.

    PubMed

    John, Kevin D.; Miskowski, Vincent M.; Vance, Michael A.; Dallinger, Richard F.; Wang, Louis C.; Geib, Steven J.; Hopkins, Michael D.

    1998-12-28

    The nature of the skeletal vibrational modes of complexes of the type M(2)(C&tbd1;CR)(4)(PMe(3))(4) (M = Mo, W; R = H, Me, Bu(t)(), SiMe(3)) has been deduced. Metrical data from X-ray crystallographic studies of Mo(2)(C&tbd1;CR)(4)(PMe(3))(4) (R = Me, Bu(t)(), SiMe(3)) and W(2)(C&tbd1;CMe)(4)(PMe(3))(4) reveal that the core bond distances and angles are within normal ranges and do not differ in a statistically significant way as a function of the alkynyl substituent, indicating that their associated force constants should be similarly invariant among these compounds. The crystal structures of Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) and Mo(2)(C&tbd1;CBu(t)())(4)(PMe(3))(4) are complicated by 3-fold disorder of the Mo(2) unit within apparently ordered ligand arrays. Resonance-Raman spectra ((1)(delta-->delta) excitation, THF solution) of Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) and its isotopomers (PMe(3)-d(9), C&tbd1;CSiMe(3)-d(9), (13)C&tbd1;(13)CSiMe(3)) exhibit resonance-enhanced bands due to a(1)-symmetry fundamentals (nu(a) = 362, nu(b) = 397, nu(c) = 254 cm(-)(1) for the natural-abundance complex) and their overtones and combinations. The frequencies and relative intensities of the fundamentals are highly sensitive to isotopic substitution of the C&tbd1;CSiMe(3) ligands, but are insensitive to deuteration of the PMe(3) ligands. Nonresonance-Raman spectra (FT-Raman, 1064 nm excitation, crystalline samples) for the Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) compounds and for Mo(2)(C&tbd1;CR)(4)(PMe(3))(4) (R = H, D, Me, Bu(t)(), SiMe(3)) and W(2)(C&tbd1;CMe)(4)(PMe(3))(4) exhibit nu(a), nu(b), and nu(c) and numerous bands due to alkynyl- and phosphine-localized modes, the latter of which are assigned by comparisons to FT-Raman spectra of Mo(2)X(4)L(4) (X = Cl, Br, I; L = PMe(3), PMe(3)-d(9))(4) and Mo(2)Cl(4)(AsMe(3))(4). Valence force-field normal-coordinate calculations on the model compound Mo(2)(C&tbd1;CH)(4)P(4), using core force constants transferred from a calculation

  12. Active mode-locking of mid-infrared quantum cascade lasers with short gain recovery time.

    PubMed

    Wang, Yongrui; Belyanin, Alexey

    2015-02-23

    We investigate the dynamics of actively modulated mid-infrared quantum cascade lasers (QCLs) using space- and time-domain simulations of coupled density matrix and Maxwell equations with resonant tunneling current taken into account. We show that it is possible to achieve active mode locking and stable generation of picosecond pulses in high performance QCLs with a vertical laser transition and a short gain recovery time by bias modulation of a short section of a monolithic Fabry-Perot cavity. In fact, active mode locking in QCLs with a short gain recovery time turns out to be more robust to the variation of parameters as compared to previously studied lasers with a long gain recovery time. We investigate the effects of spatial hole burning and phase locking on the laser output.

  13. Analysis of time-resolved interaction force mode AFM imaging using active and passive probes.

    PubMed

    Giray Oral, Hasan; Parlak, Zehra; Levent Degertekin, F

    2012-09-01

    We present an in-depth analysis of time-resolved interaction force (TRIF) mode imaging for atomic force microscopy (AFM). A nonlinear model of an active AFM probe, performing simultaneous topography and material property imaging on samples with varying elasticity and adhesion is implemented in Simulink®. The model is capable of simulating various imaging modes, probe structures, sample material properties, tip-sample interaction force models, and actuation and feedback schemes. For passive AFM cantilevers, the model is verified by comparing results from the literature. As an example of an active probe, the force sensing integrated readout and active tip (FIRAT) probe is used. Simulation results indicate that the active and damped nature of FIRAT provides a significant level of control over the force applied to the sample, minimizing sample indentation and topography error. Active tip control (ATC) preserves constant contact time during force control for stable contact while preventing the loss of material property information such as elasticity and adhesive force. Simulation results are verified by TRIF mode imaging of the samples with both soft and stiff regions. PMID:22813887

  14. Impacts of human activity modes and climate on heavy metal "spread" in groundwater are biased.

    PubMed

    Chen, Ming; Qin, Xiaosheng; Zeng, Guangming; Li, Jian

    2016-06-01

    Groundwater quality deterioration has attracted world-wide concerns due to its importance for human water supply. Although more and more studies have shown that human activities and climate are changing the groundwater status, an investigation on how different groundwater heavy metals respond to human activity modes (e.g. mining, waste disposal, agriculture, sewage effluent and complex activity) in a varying climate has been lacking. Here, for each of six heavy metals (i.e. Fe, Zn, Mn, Pb, Cd and Cu) in groundwater, we use >330 data points together with mixed-effect models to indicate that (i) human activity modes significantly influence the Cu and Mn but not Zn, Fe, Pb and Cd levels, and (ii) annual mean temperature (AMT) only significantly influences Cu and Pb levels, while annual precipitation (AP) only significantly affects Fe, Cu and Mn levels. Given these differences, we suggest that the impacts of human activity modes and climate on heavy metal "spread" in groundwater are biased. PMID:27003366

  15. Impacts of human activity modes and climate on heavy metal "spread" in groundwater are biased.

    PubMed

    Chen, Ming; Qin, Xiaosheng; Zeng, Guangming; Li, Jian

    2016-06-01

    Groundwater quality deterioration has attracted world-wide concerns due to its importance for human water supply. Although more and more studies have shown that human activities and climate are changing the groundwater status, an investigation on how different groundwater heavy metals respond to human activity modes (e.g. mining, waste disposal, agriculture, sewage effluent and complex activity) in a varying climate has been lacking. Here, for each of six heavy metals (i.e. Fe, Zn, Mn, Pb, Cd and Cu) in groundwater, we use >330 data points together with mixed-effect models to indicate that (i) human activity modes significantly influence the Cu and Mn but not Zn, Fe, Pb and Cd levels, and (ii) annual mean temperature (AMT) only significantly influences Cu and Pb levels, while annual precipitation (AP) only significantly affects Fe, Cu and Mn levels. Given these differences, we suggest that the impacts of human activity modes and climate on heavy metal "spread" in groundwater are biased.

  16. High-average-power actively-mode-locked Tm3+ fiber lasers

    NASA Astrophysics Data System (ADS)

    Eckerle, Michael; Kieleck, Christelle; Hübner, Philipp; Świderski, Jacek; Jackson, Stuart D.; Mazé, Gwenael; Eichhorn, Marc

    2012-02-01

    Fiber lasers emitting in the 2 μm wavelength range doped with thulium ions can be used as highly efficient pump sources for nonlinear converters to generate mid-infrared radiation. For spectroscopic purposes, illumination and countermeasures, a broad mid-infrared emission spectrum is advantageous. This can be reached by supercontinuum generation in fibers, e.g. fluoride fibers, which up to now has, however, only been presented with either low average power, complex Raman-shifted 1.55 μm pump sources or multi-stage amplifier pump schemes. Here we present recent results of a new actively-mode-locked single-oscillator scheme that can provide the high-repetition rate sub-ns pump pulses needed for pumping supercontinuum generators. A thulium-doped silica fiber laser is presented that provides > 11 W of average power CW-mode-locked pulses at 38 MHz repetition rate at ~ 38 ps pulse width. Upgrading the setup to allow Q-switched mode-locked operation yields mode-locked 40 MHz pulses arranged in 60 kHz bunched Q-switch envelopes and thus increases further the available peak power. In this Q-switched mode-locked regime over 5 W of average power has been achieved.

  17. Physical activity during soccer and its contribution to physical activity recommendations in normal weight and overweight children.

    PubMed

    Sacheck, Jennifer M; Nelson, Tara; Ficker, Laura; Kafka, Tamar; Kuder, Julia; Economos, Christina D

    2011-05-01

    Amid the childhood obesity epidemic, understanding how organized sports participation contributes to meeting physical activity recommendations in children is important. Anthropometrics were measured in children (n = 111; 68% female, 9.1 ± 0.8 yr) before one 50-min soccer match. Time spent at different physical activity intensity levels was examined using Actigraph accelerometers. 49% of the match time was spent in sedentary activity (25.4 ± 5.7 min), while 33% of the match (16.9 ± 4.7 min) was spent in moderate-to-vigorous activity (MVPA; p < .001). 22.5% of the children were overweight/obese and spent more time in sedentary activity (+3.2 ± 1.2 min; p < .05) and less time in MVPA (-3.0 ± 1.0 min; p < .01) compared with the normal weight children. These data demonstrate that playing an organized sport such as soccer only meets a portion (~25%) of the 60 min of MVPA recommended and even less of this recommendation is met by overweight/obese children.

  18. Normalized Legal Drafting and the Query Method.

    ERIC Educational Resources Information Center

    Allen, Layman E.; Engholm, C. Rudy

    1978-01-01

    Normalized legal drafting, a mode of expressing ideas in legal documents so that the syntax that relates the constituent propositions is simplified and standardized, and the query method, a question-asking activity that teaches normalized drafting and provides practice, are examined. Some examples are presented. (JMD)

  19. Defective Dendrite Elongation but Normal Fertility in Mice Lacking the Rho-Like GTPase Activator Dbl

    PubMed Central

    Hirsch, Emilio; Pozzato, Michela; Vercelli, Alessandro; Barberis, Laura; Azzolino, Ornella; Russo, Chiara; Vanni, Cristina; Silengo, Lorenzo; Eva, Alessandra; Altruda, Fiorella

    2002-01-01

    Dbl is the prototype of a large family of GDP-GTP exchange factors for small GTPases of the Rho family. In vitro, Dbl is known to activate Rho and Cdc42 and to induce a transformed phenotype. Dbl is specifically expressed in brain and gonads, but its in vivo functions are largely unknown. To assess its role in neurogenesis and gametogenesis, targeted deletion of the murine Dbl gene was accomplished in embryonic stem cells. Dbl-null mice are viable and did not show either decreased reproductive performances or obvious neurological defects. Histological analysis of mutant testis showed normal morphology and unaltered proliferation and survival of spermatogonia. Dbl-null brains indicated a correct disposition of the major neural structures. Analysis of cortical stratification indicated that Dbl is not crucial for neuronal migration. However, in distinct populations of Dbl-null cortical pyramidal neurons, the length of dendrites was significantly reduced, suggesting a role for Dbl in dendrite elongation. PMID:11940671

  20. Vibrational normal modes calculation in the crystalline state of methylated monosaccharides: Anomers of the methyl-D-glucopyranoside and methyl-D-xylopyranoside molecules

    NASA Astrophysics Data System (ADS)

    Taleb-Mokhtari, Ilham Naoual; Lazreg, Abbassia; Sekkal-Rahal, Majda; Bestaoui, Noreya

    2016-01-01

    A structural investigation of the organic molecules is being carried out using vibrational spectroscopy. In this study, normal co-ordinate calculations of anomers of the methyl-D-glucopyranoside and methyl-β-D-xylopyranoside in the crystalline state have been performed using the modified Urey-Bradley-Shimanouchi force field (mUBSFF) combined with an intermolecular potential energy function. The latter includes Van der Waals interactions, electrostatic terms, and explicit hydrogen bond functions. The vibrational spectra of the compounds recorded in the crystalline state, in the 4000-500 cm- 1 spectral region for the IR spectra, and in the 4000-20 cm- 1 spectral range for the Raman spectra are presented. After their careful examination, several differences in the intensities and frequency shifts have been observed. The theoretical spectra have been obtained after a tedious refinement of the force constants. Thus, on the basis of the obtained potential distribution, each observed band in IR and in Raman has been assigned to a vibrational mode. The obtained results are indeed in agreement with those observed experimentally and thus confirm the previous assignments made for the methyl-α and β-D-glucopyranoside, as well as for the methyl-β-D-xylopyranoside.

  1. Mode-locking pulse generation with MoS2-PVA saturable absorber in both anomalous and ultra-long normal dispersion regimes.

    PubMed

    Ahmed, M H M; Latiff, A A; Arof, H; Harun, S W

    2016-05-20

    We experimentally demonstrate a stable and simple mode locked erbium doped fiber laser (EDFL) utilizing passive few-layer molybdenum disulfide (MoS2) as a saturable absorber. The MoS2 is obtained by liquid phase exfoliation before it is embedded in a polymer composite film and then inserted in the laser cavity. A stable soliton pulse train started at a low threshold pump power of 20 mW in the anomalous dispersion regime after fine-tuning the rotation of the polarization controller. The central wavelength, 3 dB bandwidth, pulse width, and repetition rate of the soliton pulses are 1574.6 nm, 9.5 nm, 790 fs, and 29.5 MHz, respectively. By inserting a 850 m long dispersion shifted fiber (DSF) in the cavity, a dissipative soliton with square pulse train is obtained in the normal dispersion regime where the operating wavelength is centered at 1567.44 nm with a 3 dB bandwidth of 19.68 nm. The dissipative soliton pulse has a pulse width of 90 ns at a low repetition rate of 231.5 kHz due to the long DSF used. These results are a contribution to the pool of knowledge in nonlinear optical properties of two-dimensional nanomaterials especially for ultrafast photonic applications. PMID:27411156

  2. All-normal dispersion passively mode-locked Yb-doped fiber laser using MoS2-PVA saturable absorber

    NASA Astrophysics Data System (ADS)

    Sathiyan, S.; Velmurugan, V.; Senthilnathan, K.; Babu, P. Ramesh; Sivabalan, S.

    2016-05-01

    We demonstrate the generation of a dissipative soliton in an all-normal dispersion ytterbium (Yb)-doped fiber laser using few-layer molybdenum disulfide (MoS2) as a saturable absorber. The saturable absorber is prepared by mixing few-layer MoS2 solution with polyvinyl alcohol (PVA) to form a free-standing composite film. The modulation depth and saturation intensity of the MoS2-PVA film are 11% and 5.86 MW cm-2, respectively. By incorporating the MoS2 saturable absorber in the fiber laser cavity, the mode-locked pulses are generated with a pulse width of 1.55 ns and a 3 dB spectral bandwidth of 0.9 nm centered at 1037.5 nm. The fundamental repetition rate and the average power are measured as 15.43 MHz and 1.5 mW, respectively. These results reveal the feasibility of deploying liquid-phase exfoliated few-layer MoS2 nanosheets for dissipative soliton generation in the near-IR region.

  3. Computational modeling of the Fc αRI receptor binding in the Fc α domain of the human antibody IgA: Normal Modes Analysis (NMA) study

    NASA Astrophysics Data System (ADS)

    Jayasinghe, Manori; Posgai, Monica; Tonddast-Navaei, Sam; Ibrahim, George; Stan, George; Herr, Andrew; George Stan Group Collaboration; Herr's Group Team

    2014-03-01

    Fc αRI receptor binding in the Fc α domain of the antibody IgA triggers immune effector responses such as phagocytosis and antibody-dependent cell-mediated cytotoxicity in eukaryotic cells. Fc α is a dimer of heavy chains of the IgA antibody and each Fc α heavy chain which consisted of two immunoglobulin constant domains, CH2 and CH3, can bind one Fc αRI molecule at the CH2-CH3 interface forming a 2:1 stoichiometry. Experimental evidences confirmed that Fc αRI binding to the Fc α CH2-CH3 junction altered the kinetics of HAA lectin binding at the distant IgA1 hinge. Our focus in this research was to understand the conformational changes and the network of residues which co-ordinate the receptor binding dynamics of the Fc α dimer complex. Structure-based elastic network modeling was used to compute normal modes of distinct Fc α configurations. Asymmetric and un-liganded Fc α configurations were obtained from the high resolution crystal structure of Fc α-Fc αRI 2:1 symmetric complex of PDB ID 1OW0. Our findings confirmed that Fc αRI binding, either in asymmetric or symmetric complex with Fc α, propagated long-range conformational changes across the Fc domains, potentially also impacting the distant IgA1 hinge.

  4. Normal mode analysis based on an elastic network model for biomolecules in the Protein Data Bank, which uses dihedral angles as independent variables.

    PubMed

    Wako, Hiroshi; Endo, Shigeru

    2013-06-01

    We have developed a computer program, named PDBETA, that performs normal mode analysis (NMA) based on an elastic network model that uses dihedral angles as independent variables. Taking advantage of the relatively small number of degrees of freedom required to describe a molecular structure in dihedral angle space and a simple potential-energy function independent of atom types, we aimed to develop a program applicable to a full-atom system of any molecule in the Protein Data Bank (PDB). The algorithm for NMA used in PDBETA is the same as the computer program FEDER/2, developed previously. Therefore, the main challenge in developing PDBETA was to find a method that can automatically convert PDB data into molecular structure information in dihedral angle space. Here, we illustrate the performance of PDBETA with a protein-DNA complex, a protein-tRNA complex, and some non-protein small molecules, and show that the atomic fluctuations calculated by PDBETA reproduce the temperature factor data of these molecules in the PDB. A comparison was also made with elastic-network-model based NMA in a Cartesian-coordinate system.

  5. Effects of active music therapy on the normal brain: fMRI based evidence.

    PubMed

    Raglio, Alfredo; Galandra, Caterina; Sibilla, Luisella; Esposito, Fabrizio; Gaeta, Francesca; Di Salle, Francesco; Moro, Luca; Carne, Irene; Bastianello, Stefano; Baldi, Maurizia; Imbriani, Marcello

    2016-03-01

    The aim of this study was to investigate the neurophysiological bases of Active Music Therapy (AMT) and its effects on the normal brain. Twelve right-handed, healthy, non-musician volunteers were recruited. The subjects underwent 2 AMT sessions based on the free sonorous-music improvisation using rhythmic and melodic instruments. After these sessions, each subject underwent 2 fMRI scan acquisitions while listening to a Syntonic (SP) and an A-Syntonic (AP) Production from the AMT sessions. A 3 T Discovery MR750 scanner with a 16-channel phased array head coil was used, and the image analysis was performed with Brain Voyager QX 2.8. The listening to SP vs AP excerpts mainly activated: (1) the right middle temporal gyrus and right superior temporal sulcus, (2) the right middle frontal gyrus and in particular the right precentral gyrus, (3) the bilateral precuneus, (4) the left superior temporal sulcus and (5) the left middle temporal gyrus. These results are consistent with the psychological bases of the AMT approach and with the activation of brain areas involved in memory and autobiographical processes, and also in personal or interpersonal significant experiences. Further studies are required to confirm these findings and to explain possible effects of AMT in clinical settings.

  6. The transcriptional activator ZNF143 is essential for normal development in zebrafish

    PubMed Central

    2012-01-01

    Background ZNF143 is a sequence-specific DNA-binding protein that stimulates transcription of both small RNA genes by RNA polymerase II or III, or protein-coding genes by RNA polymerase II, using separable activating domains. We describe phenotypic effects following knockdown of this protein in developing Danio rerio (zebrafish) embryos by injection of morpholino antisense oligonucleotides that target znf143 mRNA. Results The loss of function phenotype is pleiotropic and includes a broad array of abnormalities including defects in heart, blood, ear and midbrain hindbrain boundary. Defects are rescued by coinjection of synthetic mRNA encoding full-length ZNF143 protein, but not by protein lacking the amino-terminal activation domains. Accordingly, expression of several marker genes is affected following knockdown, including GATA-binding protein 1 (gata1), cardiac myosin light chain 2 (cmlc2) and paired box gene 2a (pax2a). The zebrafish pax2a gene proximal promoter contains two binding sites for ZNF143, and reporter gene transcription driven by this promoter in transfected cells is activated by this protein. Conclusions Normal development of zebrafish embryos requires ZNF143. Furthermore, the pax2a gene is probably one example of many protein-coding gene targets of ZNF143 during zebrafish development. PMID:22268977

  7. Effects of active music therapy on the normal brain: fMRI based evidence.

    PubMed

    Raglio, Alfredo; Galandra, Caterina; Sibilla, Luisella; Esposito, Fabrizio; Gaeta, Francesca; Di Salle, Francesco; Moro, Luca; Carne, Irene; Bastianello, Stefano; Baldi, Maurizia; Imbriani, Marcello

    2016-03-01

    The aim of this study was to investigate the neurophysiological bases of Active Music Therapy (AMT) and its effects on the normal brain. Twelve right-handed, healthy, non-musician volunteers were recruited. The subjects underwent 2 AMT sessions based on the free sonorous-music improvisation using rhythmic and melodic instruments. After these sessions, each subject underwent 2 fMRI scan acquisitions while listening to a Syntonic (SP) and an A-Syntonic (AP) Production from the AMT sessions. A 3 T Discovery MR750 scanner with a 16-channel phased array head coil was used, and the image analysis was performed with Brain Voyager QX 2.8. The listening to SP vs AP excerpts mainly activated: (1) the right middle temporal gyrus and right superior temporal sulcus, (2) the right middle frontal gyrus and in particular the right precentral gyrus, (3) the bilateral precuneus, (4) the left superior temporal sulcus and (5) the left middle temporal gyrus. These results are consistent with the psychological bases of the AMT approach and with the activation of brain areas involved in memory and autobiographical processes, and also in personal or interpersonal significant experiences. Further studies are required to confirm these findings and to explain possible effects of AMT in clinical settings. PMID:25847861

  8. Teaching normal birth, normally.

    PubMed

    Hotelling, Barbara A

    2009-01-01

    Teaching normal-birth Lamaze classes normally involves considering the qualities that make birth normal and structuring classes to embrace those qualities. In this column, teaching strategies are suggested for classes that unfold naturally, free from unnecessary interventions. PMID:19436595

  9. Expression, localisation and functional activation of NFAT-2 in normal human skin, psoriasis, and cultured keratocytes.

    PubMed

    Al-Daraji, Wael I; Malak, Tamer T; Prescott, Richard J; Abdellaoui, Adel; Ali, Mahmud M; Dabash, Tarek; Zelger, Bettina G; Zelger, Bernhard

    2009-06-18

    Ciclosporin A (CsA) is widely utilized for the treatment of inflammatory skin diseases such as psoriasis. The therapeutic effects of CsA are thought to be mediated via its immunosuppressive action on infiltrating lymphocytes in skin lesions. CsA and tacrolimus block T cell activation by inhibiting the phosphatase calcineurin and preventing translocation from the cytoplasm to the nucleus of the transcription factor Nuclear Factor of Activated T cells (NFAT). As calcineurin and NFAT 1 have been shown to be functionally active in cultured human keratocytes, expression of other NFAT family members such as NFAT-2 and possible functional activation was investigated in human keratocytes. RT-PCR and Western Analysis were used to investigate the presence of NFAT-2 mRNA and protein in human keratocytes. Tissue culture of human keratocytes and immunostaining of cells on coverslips and confocal microscopy were used to assess the degree of nuclear localisation of NFAT-2 in cultured cells. Keratome biopsies were taken from patients with psoriasis (lesional and non-lesional skin) and normal skin and immunohistochemistry was used to assess the NFAT-2 localisation in these biopsies using a well characterized anti-NFAT-2 antibody. The NFAT-2 mRNA and protein expression was demonstrated using RT-PCR and Western blotting. Moreover, the expression of NFAT-2 in normal skin, non-lesional and lesional psoriasis showed a striking basal staining suggesting a role for NFAT-2 in keratocytes proliferation. A range of cell types in the skin express NFAT-2. The expression of NFAT-2 in human keratocytes and response to different agonists provides perhaps a unique opportunity to examine the regulation, subcellular localization and kinetics of translocation of different NFATs in primary cultured human cells. In these experiments the author assessed the expression, localization of NFAT-2 in cultured human keratocytes and measured the degree of nuclear localisaion of NFAT-2 using immunofluorescence

  10. A Multi-Mode Blade Damping Control using Shunted Piezoelectric Transducers with Active Feedback Structure

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin; Morrison, Carlos; Min, James

    2009-01-01

    The Structural Dynamics and. Mechanics branch (RXS) is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this presentation, only one shunted PE transducer was used to demonstrate active control of multi-mode blade resonance damping on a titanium alloy (Ti-6A1-4V) flat plate model, regardless of bending, torsion, and 2-stripe modes. This work would have a significant impact on the conventional passive shunt damping world because the standard feedback control design tools can now be used to design and implement electric shunt for vibration control. In other words, the passive shunt circuit components using massive inductors and. resistors for multi-mode resonance control can be replaced with digital codes. Furthermore, this active approach with multi patches can simultaneously control several modes in the engine operating range. Dr. Benjamin Choi presented the analytical and experimental results from this work at the Propulsion-Safety and. Affordable Readiness (P-SAR) Conference in March, 2009.

  11. Active and passive kink mode studies in a tokamak with a movable ferromagnetic walla)

    NASA Astrophysics Data System (ADS)

    Levesque, J. P.; Hughes, P. E.; Bialek, J.; Byrne, P. J.; Mauel, M. E.; Navratil, G. A.; Peng, Q.; Rhodes, D. J.; Stoafer, C. C.

    2015-05-01

    High-resolution active and passive kink mode studies are conducted in a tokamak with an adjustable ferromagnetic wall near the plasma surface. Ferritic tiles made from 5.6 mm thick Hiperco® 50 alloy have been mounted on the plasma-facing side of half of the in-vessel movable wall segments in the High Beta Tokamak-Extended Pulse device [D. A. Maurer et al., Plasma Phys. Controlled Fusion 53, 074016 (2011)] in order to explore ferritic resistive wall mode stability. Low-activation ferritic steels are a candidate for structural components of a fusion reactor, and these experiments examine MHD stability of plasmas with nearby ferromagnetic material. Plasma-wall separation for alternating ferritic and non-ferritic wall segments is adjusted between discharges without opening the vacuum vessel. Amplification of applied resonant magnetic perturbations and plasma disruptivity are observed to increase when the ferromagnetic wall is close to plasma surface instead of the standard stainless steel wall. Rapidly rotating m / n = 3 / 1 external kink modes have higher growth rates with the nearby ferritic wall. Feedback suppression of kinks is still as effective as before the installation of ferritic material in vessel, in spite of increased mode growth rates.

  12. Active and passive kink mode studies in a tokamak with a movable ferromagnetic wall

    SciTech Connect

    Levesque, J. P.; Hughes, P. E.; Bialek, J.; Byrne, P. J.; Mauel, M. E.; Navratil, G. A.; Peng, Q.; Rhodes, D. J.; Stoafer, C. C.

    2015-05-15

    High-resolution active and passive kink mode studies are conducted in a tokamak with an adjustable ferromagnetic wall near the plasma surface. Ferritic tiles made from 5.6 mm thick Hiperco{sup ®} 50 alloy have been mounted on the plasma-facing side of half of the in-vessel movable wall segments in the High Beta Tokamak-Extended Pulse device [D. A. Maurer et al., Plasma Phys. Controlled Fusion 53, 074016 (2011)] in order to explore ferritic resistive wall mode stability. Low-activation ferritic steels are a candidate for structural components of a fusion reactor, and these experiments examine MHD stability of plasmas with nearby ferromagnetic material. Plasma-wall separation for alternating ferritic and non-ferritic wall segments is adjusted between discharges without opening the vacuum vessel. Amplification of applied resonant magnetic perturbations and plasma disruptivity are observed to increase when the ferromagnetic wall is close to plasma surface instead of the standard stainless steel wall. Rapidly rotating m/n=3/1 external kink modes have higher growth rates with the nearby ferritic wall. Feedback suppression of kinks is still as effective as before the installation of ferritic material in vessel, in spite of increased mode growth rates.

  13. Detection of short-term activity avalanches in human brain default mode network with ultrafast MR encephalography

    PubMed Central

    Rajna, Zalán; Kananen, Janne; Keskinarkaus, Anja; Seppänen, Tapio; Kiviniemi, Vesa

    2015-01-01

    Recent studies pinpoint visually cued networks of avalanches with MEG/EEG data. Co-activation pattern (CAP) analysis can be used to detect single brain volume activity profiles and hemodynamic fingerprints of neuronal avalanches as sudden high signal activity peaks in classical fMRI data. In this study, we aimed to detect dynamic patterns of brain activity spreads with the use of ultrafast MR encephalography (MREG). MREG achieves 10 Hz whole brain sampling, allowing the estimation of spatial spread of an avalanche, even with the inherent hemodynamic delay of the BOLD signal. We developed a novel computational method to separate avalanche type fast activity spreads from motion artifacts, vasomotor fluctuations, and cardio-respiratory noise in human brain default mode network (DMN). Reproducible and classical DMN sources were identified using spatial ICA prior to advanced noise removal in order to assure that ICA converges to reproducible networks. Brain activity peaks were identified from parts of the DMN, and normalized MREG data around each peak were extracted individually to show dynamic avalanche type spreads as video clips within the DMN. Individual activity spread video clips of specific parts of the DMN were then averaged over the group of subjects. The experiments show that the high BOLD values around the peaks are mostly spreading along the spatial pattern of the particular DMN segment detected with ICA. With also the spread size and lifetime resembling the expected power law distributions, this indicates that the detected peaks are parts of activity avalanches, starting from (or crossing) the DMN. Furthermore, the split, one-sided sub-networks of the DMN show different spread directions within the same DMN framework. The results open possibilities to follow up brain activity avalanches in the hope to understand more about the system wide properties of diseases related to DMN dysfunction. PMID:26321936

  14. Detection of short-term activity avalanches in human brain default mode network with ultrafast MR encephalography.

    PubMed

    Rajna, Zalán; Kananen, Janne; Keskinarkaus, Anja; Seppänen, Tapio; Kiviniemi, Vesa

    2015-01-01

    Recent studies pinpoint visually cued networks of avalanches with MEG/EEG data. Co-activation pattern (CAP) analysis can be used to detect single brain volume activity profiles and hemodynamic fingerprints of neuronal avalanches as sudden high signal activity peaks in classical fMRI data. In this study, we aimed to detect dynamic patterns of brain activity spreads with the use of ultrafast MR encephalography (MREG). MREG achieves 10 Hz whole brain sampling, allowing the estimation of spatial spread of an avalanche, even with the inherent hemodynamic delay of the BOLD signal. We developed a novel computational method to separate avalanche type fast activity spreads from motion artifacts, vasomotor fluctuations, and cardio-respiratory noise in human brain default mode network (DMN). Reproducible and classical DMN sources were identified using spatial ICA prior to advanced noise removal in order to assure that ICA converges to reproducible networks. Brain activity peaks were identified from parts of the DMN, and normalized MREG data around each peak were extracted individually to show dynamic avalanche type spreads as video clips within the DMN. Individual activity spread video clips of specific parts of the DMN were then averaged over the group of subjects. The experiments show that the high BOLD values around the peaks are mostly spreading along the spatial pattern of the particular DMN segment detected with ICA. With also the spread size and lifetime resembling the expected power law distributions, this indicates that the detected peaks are parts of activity avalanches, starting from (or crossing) the DMN. Furthermore, the split, one-sided sub-networks of the DMN show different spread directions within the same DMN framework. The results open possibilities to follow up brain activity avalanches in the hope to understand more about the system wide properties of diseases related to DMN dysfunction.

  15. Detection of short-term activity avalanches in human brain default mode network with ultrafast MR encephalography.

    PubMed

    Rajna, Zalán; Kananen, Janne; Keskinarkaus, Anja; Seppänen, Tapio; Kiviniemi, Vesa

    2015-01-01

    Recent studies pinpoint visually cued networks of avalanches with MEG/EEG data. Co-activation pattern (CAP) analysis can be used to detect single brain volume activity profiles and hemodynamic fingerprints of neuronal avalanches as sudden high signal activity peaks in classical fMRI data. In this study, we aimed to detect dynamic patterns of brain activity spreads with the use of ultrafast MR encephalography (MREG). MREG achieves 10 Hz whole brain sampling, allowing the estimation of spatial spread of an avalanche, even with the inherent hemodynamic delay of the BOLD signal. We developed a novel computational method to separate avalanche type fast activity spreads from motion artifacts, vasomotor fluctuations, and cardio-respiratory noise in human brain default mode network (DMN). Reproducible and classical DMN sources were identified using spatial ICA prior to advanced noise removal in order to assure that ICA converges to reproducible networks. Brain activity peaks were identified from parts of the DMN, and normalized MREG data around each peak were extracted individually to show dynamic avalanche type spreads as video clips within the DMN. Individual activity spread video clips of specific parts of the DMN were then averaged over the group of subjects. The experiments show that the high BOLD values around the peaks are mostly spreading along the spatial pattern of the particular DMN segment detected with ICA. With also the spread size and lifetime resembling the expected power law distributions, this indicates that the detected peaks are parts of activity avalanches, starting from (or crossing) the DMN. Furthermore, the split, one-sided sub-networks of the DMN show different spread directions within the same DMN framework. The results open possibilities to follow up brain activity avalanches in the hope to understand more about the system wide properties of diseases related to DMN dysfunction. PMID:26321936

  16. The 2013 earthquake swarm in Helike, Greece: seismic activity at the root of old normal faults

    NASA Astrophysics Data System (ADS)

    Kapetanidis, V.; Deschamps, A.; Papadimitriou, P.; Matrullo, E.; Karakonstantis, A.; Bozionelos, G.; Kaviris, G.; Serpetsidaki, A.; Lyon-Caen, H.; Voulgaris, N.; Bernard, P.; Sokos, E.; Makropoulos, K.

    2015-09-01

    The Corinth Rift in Central Greece has been studied extensively during the past decades, as it is one of the most seismically active regions in Europe. It is characterized by normal faulting and extension rates between 6 and 15 mm yr-1 in an approximately N10E° direction. On 2013 May 21, an earthquake swarm was initiated with a series of small events 4 km southeast of Aigion city. In the next days, the seismic activity became more intense, with outbursts of several stronger events of magnitude between 3.3 and 3.7. The seismicity migrated towards the east during June, followed by a sudden activation of the western part of the swarm on July 15th. More than 1500 events have been detected and manually analysed during the period between 2013 May 21 and August 31, using over 15 local stations in epicentral distances up to 30 km and a local velocity model determined by an error minimization method. Waveform similarity-based analysis was performed, revealing several distinct multiplets within the earthquake swarm. High-resolution relocation was applied using the double-difference algorithm HypoDD, incorporating both catalogue and cross-correlation differential traveltime data, which managed to separate the initial seismic cloud into several smaller, densely concentrated spatial clusters of strongly correlated events. Focal mechanism solutions for over 170 events were determined using P-wave first motion polarities, while regional waveform modelling was applied for the calculation of moment tensors for the 18 largest events of the sequence. Selected events belonging to common spatial groups were considered for the calculation of composite mechanisms to characterize different parts of the swarm. The solutions are mainly in agreement with the regional NNE-SSW extension, representing typical normal faulting on 30-50° north-dipping planes, while a few exhibit slip in an NNE-SSW direction, on a roughly subhorizontal plane. Moment magnitudes were calculated by spectral analysis

  17. Diuretic activity of the aqueous extracts of Carum carvi and Tanacetum vulgare in normal rats.

    PubMed

    Lahlou, Sanaa; Tahraoui, Adil; Israili, Zafar; Lyoussi, Badiaâ

    2007-04-01

    In the Moroccan traditional medicine, the ripe fruits of Carum carvi L. (Apiaceae) and the leaves of Tanacetum vulgare L. (Asteraceae/Compositae), two widely available plant materials, are used as diuretics. Since, the diuretic activity of these substances has not been investigated in scientifically controlled studies, the aim of the present study was to evaluate the diuretic potential of aqueous extracts of Carum carvi fruit (caraway) and the leaves of Tanacetum vulgare (tansy) in normal rats after acute and sub-chronic oral administration. Water extracts of Carum carvi and Tanacetum vulgare (100 mg/kg) or the reference drug, furosemide (10 mg/kg) were administrated orally to male Wistar rats and their urine output was quantitated at several intervals of time after the dose. After single doses of the extracts of both caraway seeds and tansy leaves, urine output was significantly increased at all time points, and at 24 h after the dose, the total volume of urine excreted was similar for the plant extracts and furosemide. Both extracts increased urinary levels of Na(+) and K(+), to about the same extent, while furosemide increased urinary levels of only Na(+) and decreased urinary K(+). Despite changes in urinary excretion of the electrolytes, plasma Na(+) and K(+) levels were not affected by any of the three substances. In the 8-day sub-chronic study, all three substances induced significant diuresis and natriuresis; only tansy increased urinary potassium excretion. The plant extracts did not appear to have renal toxicity or any other adverse effects during the study period. In conclusion, water extracts of both Carum carvi and Tanacetum vulgare have strong diuretic action confirming their ethnopharmacological use. From the pattern of excretion of water, sodium and potassium, it may be deduced that there are atleast two types of active principals present in these extracts, one having a furosemide-like activity and the other a thiazide-like activity.

  18. Cysteine Proteases: Modes of Activation and Future Prospects as Pharmacological Targets

    PubMed Central

    Verma, Sonia; Dixit, Rajnikant; Pandey, Kailash C.

    2016-01-01

    Proteolytic enzymes are crucial for a variety of biological processes in organisms ranging from lower (virus, bacteria, and parasite) to the higher organisms (mammals). Proteases cleave proteins into smaller fragments by catalyzing peptide bonds hydrolysis. Proteases are classified according to their catalytic site, and distributed into four major classes: cysteine proteases, serine proteases, aspartic proteases, and metalloproteases. This review will cover only cysteine proteases, papain family enzymes which are involved in multiple functions such as extracellular matrix turnover, antigen presentation, processing events, digestion, immune invasion, hemoglobin hydrolysis, parasite invasion, parasite egress, and processing surface proteins. Therefore, they are promising drug targets for various diseases. For preventing unwanted digestion, cysteine proteases are synthesized as zymogens, and contain a prodomain (regulatory) and a mature domain (catalytic). The prodomain acts as an endogenous inhibitor of the mature enzyme. For activation of the mature enzyme, removal of the prodomain is necessary and achieved by different modes. The pro-mature domain interaction can be categorized as protein–protein interactions (PPIs) and may be targeted in a range of diseases. Cysteine protease inhibitors are available that can block the active site but no such inhibitor available yet that can be targeted to block the pro-mature domain interactions and prevent it activation. This review specifically highlights the modes of activation (processing) of papain family enzymes, which involve auto-activation, trans-activation and also clarifies the future aspects of targeting PPIs to prevent the activation of cysteine proteases. PMID:27199750

  19. Cysteine Proteases: Modes of Activation and Future Prospects as Pharmacological Targets.

    PubMed

    Verma, Sonia; Dixit, Rajnikant; Pandey, Kailash C

    2016-01-01

    Proteolytic enzymes are crucial for a variety of biological processes in organisms ranging from lower (virus, bacteria, and parasite) to the higher organisms (mammals). Proteases cleave proteins into smaller fragments by catalyzing peptide bonds hydrolysis. Proteases are classified according to their catalytic site, and distributed into four major classes: cysteine proteases, serine proteases, aspartic proteases, and metalloproteases. This review will cover only cysteine proteases, papain family enzymes which are involved in multiple functions such as extracellular matrix turnover, antigen presentation, processing events, digestion, immune invasion, hemoglobin hydrolysis, parasite invasion, parasite egress, and processing surface proteins. Therefore, they are promising drug targets for various diseases. For preventing unwanted digestion, cysteine proteases are synthesized as zymogens, and contain a prodomain (regulatory) and a mature domain (catalytic). The prodomain acts as an endogenous inhibitor of the mature enzyme. For activation of the mature enzyme, removal of the prodomain is necessary and achieved by different modes. The pro-mature domain interaction can be categorized as protein-protein interactions (PPIs) and may be targeted in a range of diseases. Cysteine protease inhibitors are available that can block the active site but no such inhibitor available yet that can be targeted to block the pro-mature domain interactions and prevent it activation. This review specifically highlights the modes of activation (processing) of papain family enzymes, which involve auto-activation, trans-activation and also clarifies the future aspects of targeting PPIs to prevent the activation of cysteine proteases. PMID:27199750

  20. Fifty-ps Raman fiber laser with hybrid active-passive mode locking.

    PubMed

    Kuznetsov, A G; Kharenko, D S; Podivilov, E V; Babin, S A

    2016-07-25

    Actively mode locked Raman lasing in a ring PM-fiber cavity pumped by a linearly polarized Yb-doped fiber laser is studied. At co-propagating pumping, a stochastic pulse with duration defined by the AOM switching time (~15 ns) is generated with the round-trip period. At counter-propagating pumping, one or several sub-ns pulses (within the AOM switching envelope) are formed. It has been found that the formation of such stable multi-pulse structure is defined by the single-pulse energy limit (~20 nJ) set by the second-order Raman generation. Adding a NPE-based saturable absorber in the actively mode locked cavity, results in sufficient shortening of the generated pulses both in single- and multi-pulse regimes (down to 50 ps). A model is developed adequately describing the regimes. PMID:27464081

  1. Default-Mode Network Activity Identified by Group Independent Component Analysis

    NASA Astrophysics Data System (ADS)

    Liu, Conghui; Zhuang, Jie; Peng, Danling; Yu, Guoliang; Yang, Yanhui

    Default-mode network activity refers to some regional increase in blood oxygenation level-dependent (BOLD) signal during baseline than cognitive tasks. Recent functional imaging studies have found co-activation in a distributed network of cortical regions, including ventral anterior cingulate cortex (vACC) and posterior cingulate cortex (PPC) that characterize the default mode of human brain. In this study, general linear model and group independent component analysis (ICA) were utilized to analyze the fMRI data obtained from two language tasks. Both methods yielded similar, but not identical results and detected a resting deactivation network at some midline regions including anterior and posterior cingulate cortex and precuneus. Particularly, the group ICA method segregated functional elements into two separate maps and identified ventral cingulate component and fronto-parietal component. These results suggest that these two components might be linked to different mental function during "resting" baseline.

  2. PTK6/BRK is expressed in the normal mammary gland and activated at the plasma membrane in breast tumors.

    PubMed

    Peng, Maoyu; Emmadi, Rajyasree; Wang, Zebin; Wiley, Elizabeth L; Gann, Peter H; Khan, Seema A; Banerji, Nilanjana; McDonald, William; Asztalos, Szilard; Pham, Thao N D; Tonetti, Debra A; Tyner, Angela L

    2014-08-15

    Protein Tyrosine kinase 6 (PTK6/BRK) is overexpressed in the majority of human breast tumors and breast tumor cell lines. It is also expressed in normal epithelial linings of the gastrointestinal tract, skin, and prostate. To date, expression of PTK6 has not been extensively examined in the normal human mammary gland. We detected PTK6 mRNA and protein expression in the immortalized normal MCF-10A human mammary gland epithelial cell line, and examined PTK6 expression and activation in a normal human breast tissue microarray, as well as in human breast tumors. Phosphorylation of tyrosine residue 342 in the PTK6 activation loop corresponds with its activation. Similar to findings in the prostate, we detect nuclear and cytoplasmic PTK6 in normal mammary gland epithelial cells, but no phosphorylation of tyrosine residue 342. However, in human breast tumors, striking PTK6 expression and phosphorylation of tyrosine 342 is observed at the plasma membrane. PTK6 is expressed in the normal human mammary gland, but does not appear to be active and may have kinase-independent functions that are distinct from its cancer promoting activities at the membrane. Understanding consequences of PTK6 activation at the plasma membrane may have implications for developing novel targeted therapies against this kinase.

  3. Trypanosoma cruzi cytosolic alkaline antigens (FI) induce polyclonal activation in murine normal B cells.

    PubMed

    Montes, C L; Vottero-Cima, E; Gruppi, A

    1996-08-01

    Several reports have described polyclonal activation in mice acutely infected with Trypanosoma cruzi. The aim of this work was to analyse the participation of one T. cruzi antigenic fraction in this immunological event. The antigen selected was FI, an antigenic fraction of pI 7-9 obtained from T. cruzi cytosol separated by isoelectricfocusing. FI is constituted by molecules with molecular weights of around 60 and 20 KDa. The authors assayed the ability of this antigenic fraction to induce polyclonal activation of spleen mononuclear cells from normal (NSMC) BALB/c mice. NSMC showed a marked lymphoproliferative response measured by 3H-thymidine incorporation after 3 days of culture in presence of FI. The values reached by FI-stimulated cells were 10 times higher than the controls (non-stimulated cells). This effect was dose-dependent. Furthermore, the authors observed that a purified T-cell population in the presence of adherent cells was unaffected by FI. Additionally, in a culture of NSMC, FI stimulated the proliferation of B cells as observed by the increase of the percentage of B220+ cells determined by FACS using FITC-conjugated anti-mouse B220. The authors noticed that the percentage of B220+Ly1+(CD5) populations in the presence of FI did not change with respect to the control (non-stimulated cells), indicating that FI expanded both conventional and CD5+ B cells. The isotypic pattern of the antibodies produced after 6 days of culture of NSMC in the presence of FI was predominantly IgM, which reacted with highly conserved antigens such as actin, myosin, myoglobin, thyroglobulin and carbonic anhydrase, but did not react with FI. A slight increase of IgG1 and IgG3 with respect to the control was observed but no changes on the levels of IgG2 was noticed. These results indicate that FI promotes activation, proliferation and differentiation in antibody-secreting cells of normal murine B lymphocytes.

  4. Local brain atrophy accounts for functional activity differences in normal aging.

    PubMed

    Kalpouzos, Grégoria; Persson, Jonas; Nyberg, Lars

    2012-03-01

    Functional brain imaging studies of normal aging typically show age-related under- and overactivations during episodic memory tasks. Older individuals also undergo nonuniform gray matter volume (GMv) loss. Thus, age differences in functional brain activity could at least in part result from local atrophy. We conducted a series of voxel-based blood oxygen level-dependent (BOLD)-GMv analyses to highlight whether age-related under- and overrecruitment was accounted for by GMv changes. Occipital GMv loss accounted for underrecruitment at encoding. Efficiency reduction of sensory-perceptual mechanisms underpinned by these areas may partly be due to local atrophy. At retrieval, local GMv loss accounted for age-related overactivation of left dorsolateral prefrontal cortex, but not of left dorsomedial prefrontal cortex. Local atrophy also accounted for age-related overactivation in left lateral parietal cortex. Activity in these frontoparietal regions correlated with performance in the older group. Atrophy in the overrecruited regions was modest in comparison with other regions as shown by a between-group voxel-based morphometry comparison. Collectively, these findings link age-related structural differences to age-related functional under- as well as overrecruitment.

  5. Activity of glycogen synthase and glycogen phosphorylase in normal and cirrhotic rat liver during glycogen synthesis from glucose or fructose.

    PubMed

    Bezborodkina, Natalia N; Chestnova, Anna Yu; Okovity, Sergey V; Kudryavtsev, Boris N

    2014-03-01

    Cirrhotic patients often demonstrate glucose intolerance, one of the possible causes being a decreased glycogen-synthesizing capacity of the liver. At the same time, information about the rates of glycogen synthesis in the cirrhotic liver is scanty and contradictory. We studied the dynamics of glycogen accumulation and the activity of glycogen synthase (GS) and glycogen phosphorylase (GP) in the course of 120min after per os administration of glucose or fructose to fasted rats with CCl4-cirrhosis or fasted normal rats. Blood serum and liver pieces were sampled for examinations. In the normal rat liver administration of glucose/fructose initiated a fast accumulation of glycogen, while in the cirrhotic liver glycogen was accumulated with a 20min delay and at a lower rate. In the normal liver GS activity rose sharply and GPa activity dropped in the beginning of glycogen synthesis, but 60min later a high synthesis rate was sustained at the background of a high GS and GPa activity. Contrariwise, in the cirrhotic liver glycogen was accumulated at the background of a decreased GS activity and a low GPa activity. Refeeding with fructose resulted in a faster increase in the GS activity in both the normal and the cirrhotic liver than refeeding with glucose. To conclude, the rate of glycogen synthesis in the cirrhotic liver is lower than in the normal one, the difference being probably associated with a low GS activity.

  6. Upper Limits of Normal for Alanine Aminotransferase Activity in the United States Population

    PubMed Central

    Ruhl, Constance E.; Everhart, James E.

    2011-01-01

    Background & Rationale Alanine aminotransferase (ALT) is an important test for liver disease, yet there is no generally accepted upper limit of normal (ULN) in the United States. Furthermore, the ability of ALT to differentiate persons with and without liver disease is uncertain. We examined cut-offs for ALT for their ability to discriminate between persons with positive hepatitis C virus (HCV) RNA and those at low risk for liver injury in the U.S. population. Methods Among adult participants in the 1999–2008 U.S. National Health and Nutrition Examination Survey, 259 were positive for serum HCV RNA and 3,747 were at low risk for liver injury (negative HCV RNA and hepatitis B surface antigen, low alcohol consumption, no evidence of diabetes, normal body mass index and waist circumference). Serum ALT activity was measured centrally. Results Maximum correct classification was achieved at ALT=29 IU/L for men (88% sensitivity, 83% specificity) and 22 (89% sensitivity, 82% specificity) for women. The cut-off for 95% sensitivity was an ALT=24 IU/L (70% specificity) for men and 18 (63% specificity) for women. The cut-off for 95% specificity was an ALT=44 IU/L (64% sensitivity) for men and 32 (59% sensitivity) for women. The area under the curve was 0.929 for men and 0.915 for women. If the cut-offs with the best correct classification were applied to the entire population, 36.4% of men and 28.3% of women would have had abnormal ALT. Conclusion ALT discriminates persons infected with HCV from those at low risk of liver disease, but would be considered elevated in a large proportion of the U.S. population. PMID:21987480

  7. Stability of the Tilt Modes of an Actively Controlled Flywheel Analyzed

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.; Kascak, Albert F.

    1999-01-01

    Applications of strongly gyroscopic rotors are becoming important, including flywheels for terrestrial and space energy storage and various attitude control devices for spacecraft. Some of these applications, especially the higher speed ones for energy storage, will have actively controlled magnetic bearings. These bearings will be required where speeds are too high for conventional bearings, where adequate lubrication is undesirable or impossible, or where bearing losses must be minimized for efficient energy storage. Flywheel rotors are highly gyroscopic, and above some speed that depends on the bandwidth of the feedback system, they always become unstable in an actively controlled magnetic bearing system. To assess ways to prevent instability until speeds well above the desired operating range, researchers at the NASA Lewis Research Center used a commercial controls code to calculate the eigenvalues of the tilt modes of a rigid gyroscopic rotor supported by active magnetic bearings. The real part of the eigenvalue is the negative of the damping of the mode, and the imaginary part is approximately equal to the mode s frequency.

  8. Mode of Action of Lactoperoxidase as Related to Its Antimicrobial Activity: A Review

    PubMed Central

    Bafort, F.; Parisi, O.; Perraudin, J.-P.; Jijakli, M. H.

    2014-01-01

    Lactoperoxidase is a member of the family of the mammalian heme peroxidases which have a broad spectrum of activity. Their best known effect is their antimicrobial activity that arouses much interest in in vivo and in vitro applications. In this context, the proper use of lactoperoxidase needs a good understanding of its mode of action, of the factors that favor or limit its activity, and of the features and properties of the active molecules. The first part of this review describes briefly the classification of mammalian peroxidases and their role in the human immune system and in host cell damage. The second part summarizes present knowledge on the mode of action of lactoperoxidase, with special focus on the characteristics to be taken into account for in vitro or in vivo antimicrobial use. The last part looks upon the characteristics of the active molecule produced by lactoperoxidase in the presence of thiocyanate and/or iodide with implication(s) on its antimicrobial activity. PMID:25309750

  9. Influences of NREM sleep on the activity of tonic vs. inspiratory phasic muscles in normal men.

    PubMed

    Tangel, D J; Mezzanotte, W S; Sandberg, E J; White, D P

    1992-09-01

    Studies of sleep influences on human pharyngeal and other respiratory muscles suggest that the activity of these muscles may be affected by non-rapid-eye-movement (NREM) sleep in a nonuniform manner. This variable sleep response may relate to the pattern of activation of the muscle (inspiratory phasic vs. tonic) and peripheral events occurring in the airway. Furthermore, the ability of these muscles to respond to respiratory stimuli during NREM sleep may also differ. To systematically investigate the effect of NREM sleep on respiratory muscle activity, we studied two tonic muscles [tensor palatini (TP), masseter (M)] and two inspiratory phasic ones [genioglossus (GG), diaphragm (D)], also measuring the response of these muscles to inspiratory resistive loading (12 cmH2O.l-1.s) during wakefulness and NREM sleep. Seven normal male subjects were studied on a single night with intramuscular electrodes placed in the TP and GG and surface electrodes placed over the D and M. Sleep stage, inspiratory airflow, and moving time average electromyograph (EMG) of the above four muscles were continuously recorded. The EMG of both tonic muscles fell significantly (P less than 0.05) during NREM sleep [TP awake, 4.3 +/- 0.05 (SE) arbitrary units, stage 2, 1.1 +/- 0.2; stage 3/4, 1.0 +/- 0.2. Masseter awake, 4.8 +/- 0.6; stage 2, 3.3 +/- 0.5; stage 3/4, 3.1 +/- 0.5]. On the other hand, the peak phasic EMG of both inspiratory phasic muscles (GG and D) was well maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Assessment of uterine and umbilical artery velocimetry during latent and active phases of normal labor.

    PubMed

    Meizner, I; Levy, A; Katz, M

    1993-01-01

    Twenty healthy parturients in active labor were monitored with continuous wave Doppler to assess changes in uterine and umbilical velocity waveforms. Each case served as its own control. Tracings of fetal heart rate monitoring were normal in all patients. The analysis of the waveforms included the peak systolic/end-diastolic ratio for the umbilical circulation (umbilical artery), and the systolic minus diastolic velocity divided by systolic velocity (resistance index) was used as an indication of downstream resistance in the uterine arteries. Recordings from umbilical, left and right uterine arteries were obtained during various stages of progression of labor as indicated by Friedman's curve. In latent phase labor with intact membranes, as well as in three consecutive measurements throughout active phase labor until delivery, umbilical artery systolic/end-diastolic ratios, before, during and after contraction did not change--2.2 +/- 0.5, 2.3 +/- 0.6, 2.2 +/- 0.3 and 2.5 +/- 0.7 (NS). No changes in the resistance to flow in the left and right uterine arteries were recorded during both latent and active phases of labor--0.53 +/- 0.09, 0.52 +/- 0.1, 0.5 +/- 0.07, 0.56 +/- 0.07 (NS) and 0.59 +/- 0.1, 0.57 +/- 0.1, 0.56 +/- 0.1, 0.59 +/- 0.08 (NS), respectively. These results suggest stability of the fetal cardiovascular system ensuring continuous constant gas exchange process during labor, enabling most term fetuses to tolerate labor to a degree where minimal if any metabolic changes occur.

  11. PCNA immunoreactivity revealing normal proliferative activity in the brain of adult Lampetra planeri (Bloch, 1784).

    PubMed

    Margotta, Vito; Caronti, Brunella; Colombari, Paolo Tito; Castiglia, Riccardo

    2007-01-01

    It is now well known that the Teleosts among Osteichthyes, Urodele and Anuran Amphibians, Lacertilian Reptiles possess encephalic natural proliferative activities even into adulthood, as demonstrated by a great number of researches performed both under normal and various experimental conditions. Few years ago we have undertaken in adult heterothermic vertebrates a reappraisal on spontaneous cerebral proliferative events involving some organisms (Podarcis sicula, Triturus carnifex, Rana esculenta, Carassius carassius) representative of these vertebrates and belonging to the same or phylogenetically similar species used by previous researchers in studies having the same object. In our investigations, these performances were revealed by a proliferative immunocytochemical marker, the Proliferating Cell Nuclear Antigen (PCNA). At this point of our study in the scenario emerging from findings a missing piece is represented by Petromyzontidae. To fill up this gap in the present investigation, using our usual test, we have paid attention to adult specimens of Lampetra planeri. The obtained immunostaining panorama has revealed the presence of a considerable number of spontaneous proliferative activities. These events might differ in quantity, in various encephalic districts. PCNA-labelled cells appeared scattered in the cranial portion of olfactory bulbs, while the PCNA expression has been observed steadily localized with a distinctly continous distribution in cells interposed among the ependymal epithelium which lines the cavities of the proximal portion of the olfactory region and of the cerebral ventricles. DNA synthesis activity has been also found in cells scattered in the telencephalic, diencephalic, mesencephalic and medulla oblongata periventricular grey. This immunoreactivity was not revealable in the cerebellum. Our findings are discussed in the light of bibliographic news.

  12. The loss of independence in activities of daily living: the role of low normal cognitive function in elderly nuns.

    PubMed Central

    Greiner, P A; Snowdon, D A; Schmitt, F A

    1996-01-01

    OBJECTIVES. This study investigated the role of low normal cognitive function in the subsequent loss of independence in activities of daily living. METHODS. Of the 678 elderly nuns who-completed cognitive and physical function assessments in 1992/93, 575 were reassessed in 1993/94. Mini-Mental State Examination scores were divided into three categories and related to loss of independence in six activities of daily living. RESULTS. Participants with low normal cognitive function at first assessment had twice the risk of losing independence in three activities of daily living by second assessment relative to those with high normal cognitive function. This relationship was largely due to a progression from low normal cognitive function at first assessment to impaired cognitive function at second assessment and was associated with an elevated risk of losing independence in the six activities. CONCLUSIONS. Progression from low normal to impaired cognitive function was associated with loss of independence in activities of daily living. Thus low normal cognitive function could be viewed as an early warning of impending cognitive impairment and loss of physical function. PMID:8561244

  13. Bone morphogenetic protein-7 expression and activity in the human adult normal kidney is predominantly localized to the distal nephron.

    PubMed

    Wetzel, P; Haag, J; Câmpean, V; Goldschmeding, R; Atalla, A; Amann, K; Aigner, T

    2006-08-01

    Bone morphogenetic protein-7 (BMP)-7 plays an important role during fetal kidney development. In the adult, BMP-7 is most strongly expressed in the kidney compared to other organs, but the exact expression pattern as well as the function of BMP-7 is unclear. The major aim of the present study was to define which parts of the human kidney do physiologically express BMP-7 and which cells appear to be targets of BMP activity by showing phosphorylated BMP-receptor-associated Smads 1, 5, or 8 and inhibitor of differentiation factor 1 (ID1) expression. BMP-7 expression was localized by immunohistology to the epithelia of the distal tubule as well as the collecting ducts (CDs). Phospho-Smads 1/5/8 and ID1 expression largely colocalized with BMP-7 and was also localized in the epithelia of the distal tubule and the CDs. This was confirmed by polymerase chain reaction-based mRNA expression analysis. In vitro, proximal tubular cells (PTCs) expressed BMP receptors and BMP-receptor-associated Smads and were reactive to BMP-7. Our data indicate that BMP-7 expression in the adult human kidney appears to be more restricted than in the fetal situation and predominantly found in the distal nephron. Also, evidence of in vivo BMP signalling (i.e. phospho-Smads and ID1 expression) was found there. These findings suggest that BMP-7 plays a physiological role mostly in this part of the kidney. Still, as reported previously, PTCs are responsive to BMP-7, but presumably not in an autocrine or paracrine mode in normal adult kidneys. PMID:16807538

  14. QuickView video preview software of colon capsule endoscopy: reliability in presenting colorectal polyps as compared to normal mode reading.

    PubMed

    Farnbacher, Michael J; Krause, Horst H; Hagel, Alexander F; Raithel, Martin; Neurath, Markus F; Schneider, Thomas

    2014-03-01

    OBJECTIVE. Colon capsule endoscopy (CCE) proved to be highly sensitive in detection of colorectal polyps (CP). Major limitation is the time-consuming video reading. The aim of this prospective, double-center study was to assess the theoretical time-saving potential and its possible impact on the reliability of "QuickView" (QV), in the presentation of CP as compared to normal mode (NM). METHODS. During NM reading of 65 CCE videos (mean patient´s age 56 years), all frames showing CPs were collected and compared to the number of frames presented by QV at increasing QV settings (10, 20, ... 80%). Reliability of QV in presenting polyps <6 mm and ≥6 mm (significant polyp), and identifying patients for subsequent therapeutic colonoscopy, capsule egestion rate, cleansing level, and estimated time-saving potential were assessed. RESULTS. At a 30% QV setting, the QV video presented 89% of the significant polyps and 86% of any polyps with ≥1 frame (per-polyp analysis) identified in NM before. At a 10% QV setting, 98% of the 52 patients with significant polyps could be identified (per-patient analysis) by QV video analysis. Capsule excretion rate was 74% and colon cleanliness was adequate in 85%. QV´s presentation rate correlates to the QV setting, the polyp size, and the number of frames per finding. CONCLUSIONS. Depending on its setting, the reliability of QV in presenting CP as compared to NM reading is notable. However, if no significant polyp is presented by QV, NM reading must be performed afterwards. The reduction of frames to be analyzed in QV might speed up identification of candidates for therapeutic colonoscopy. PMID:24325660

  15. YANA – a software tool for analyzing flux modes, gene-expression and enzyme activities

    PubMed Central

    Schwarz, Roland; Musch, Patrick; von Kamp, Axel; Engels, Bernd; Schirmer, Heiner; Schuster, Stefan; Dandekar, Thomas

    2005-01-01

    Background A number of algorithms for steady state analysis of metabolic networks have been developed over the years. Of these, Elementary Mode Analysis (EMA) has proven especially useful. Despite its low user-friendliness, METATOOL as a reliable high-performance implementation of the algorithm has been the instrument of choice up to now. As reported here, the analysis of metabolic networks has been improved by an editor and analyzer of metabolic flux modes. Analysis routines for expression levels and the most central, well connected metabolites and their metabolic connections are of particular interest. Results YANA features a platform-independent, dedicated toolbox for metabolic networks with a graphical user interface to calculate (integrating METATOOL), edit (including support for the SBML format), visualize, centralize, and compare elementary flux modes. Further, YANA calculates expected flux distributions for a given Elementary Mode (EM) activity pattern and vice versa. Moreover, a dissection algorithm, a centralization algorithm, and an average diameter routine can be used to simplify and analyze complex networks. Proteomics or gene expression data give a rough indication of some individual enzyme activities, whereas the complete flux distribution in the network is often not known. As such data are noisy, YANA features a fast evolutionary algorithm (EA) for the prediction of EM activities with minimum error, including alerts for inconsistent experimental data. We offer the possibility to include further known constraints (e.g. growth constraints) in the EA calculation process. The redox metabolism around glutathione reductase serves as an illustration example. All software and documentation are available for download at . Conclusion A graphical toolbox and an editor for METATOOL as well as a series of additional routines for metabolic network analyses constitute a new user-friendly software for such efforts. PMID:15929789

  16. Accessible cultural mind-set modulates default mode activity: evidence for the culturally situated brain.

    PubMed

    Wang, Chenbo; Oyserman, Daphna; Liu, Qiang; Li, Hong; Han, Shihui

    2013-01-01

    Self-construal priming modulates human behavior and associated neural activity. However, the neural activity associated with the self-construal priming procedure itself remains unknown. It is also unclear whether and how self-construal priming affects neural activity prior to engaging in a particular task. To address this gap, we scanned Chinese adults, using functional magnetic resonance imaging, during self-construal priming and a following resting state. We found that, relative to a calculation task, both interdependent and independent self-construal priming activated the ventral medial prefrontal cortex (MPFC) and the posterior cingulate cortex (PCC). The contrast of interdependent vs. independent self-construal priming also revealed increased activity in the dorsal MPFC and left middle frontal cortex. The regional homogeneity analysis of the resting-state activity revealed increased local synchronization of spontaneous activity in the dorsal MPFC but decreased local synchronization of spontaneous activity in the PCC when contrasting interdependent vs. independent self-construal priming. The functional connectivity analysis of the resting-state activity, however, did not show significant difference in synchronization of activities in remote brain regions between different priming conditions. Our findings suggest that accessible collectivistic/individualistic mind-set induced by self-construal priming is associated with modulations of both task-related and resting-state activity in the default mode network.

  17. Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections.

    PubMed

    Sampath Kumar, T S; Madhumathi, K; Rubaiya, Y; Doble, Mukesh

    2015-01-01

    Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP) bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA) nanoparticles has been developed. Antibacterial ions such as zinc, silver, and strontium have been incorporated into CDHA at concentrations of 6, 0.25-0.75, and 2.5-7.5 at. %, respectively. The samples were found to be phase pure, acicular nanoparticles of length 40-50 nm and width 5-6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for 5 days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on Staphylococcus aureus and Escherichia coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria, while SrCDHA was weakly active against S. aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity, and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug

  18. Nd:YAG laser with passive-active mode-locking

    NASA Astrophysics Data System (ADS)

    Zhao, Weijiang; Chen, Zhenlei; Ren, Deming; Qu, Yanchen; Mo, Shuang; Huang, Jinjer; Andreev, Yury M.; Gorobets, Vadim A.; Petukhov, Vladimir O.; Zemlyanov, Aleksei A.

    2008-03-01

    All solid-state flash-lamp pumped passive-active mode-locked Nd3+:YAG laser is designed and experimentally studded. Saturation absorber Cr4+:YAG with initial transparency 25 and 47% are used as a passive Q-switcher and acousto-optical fused quartz modulator as an active mode-locker. Efficient length of the laser cavity with fixed mirror positions (1.45 m spaced) is droved by changes of 100% flat mirror for concave mirrors with different focus lengths. Changeable output mirrors with transparencies of 15 and 50% are used. Driving of the cavity parameters, laser and acousto-optical modulator power supply voltages let us to control output pulse train and single pulse parameters. As it goes from the analyses of oscillograms fixed with pyroelectric detector (τ=0.5 ns) and 1 GHz oscilloscope, over 95% of pulse output energy has been mode-locked. Average duration of the pulse train envelope of 5 to 50 single pulses at FWHM has been droved within 50 to 600 ns. When this single pulse duration is controlled but did not exceed 2 ns.

  19. Metachronal activity of cultured mucociliary epithelium under normal and stimulated conditions.

    PubMed

    Gheber, L; Priel, Z

    1994-01-01

    In the present work we measured in real time the metachronism and degree of correlation between beating cilia from cultured mucociliary epithelium. The method is based on simultaneous measurement of ciliary beat frequency, phase shifts, and correlation factors in two directions: parallel and perpendicular to the effective stroke direction (ESD). From the phase shifts the lengths of wave components, and consequently the metachronal wavelength and direction, were evaluated. On active ciliary areas of cultured frog esophagus under normal conditions, a relatively high degree of correlation is observed, but cilia are more correlated in direction parallel to ESD which is also the direction of the mucus propulsion. The length of the wave component parallel to ESD is more than twice as large as that of the perpendicular component. The metachronal wavelength was found to be in the range of 5-9 microns, and the direction of the wave propagation was in the range of 90 degrees-125 degrees clockwise to the ESD. When ciliary beat frequency was rapidly increased by extracellular ATP or acetylcholine, only minor effects were observed on the degree of correlation between beating cilia. The length of the wave component parallel to ESD showed the most dramatic effect increasing up to tenfold. The perpendicular to ESD component was not affected by the stimulation. Consequently, the metachronism became more laeoplectic with the angle between the ESD and the wave directions decreasing by 10 degrees-30 degrees, and the metachronal wavelength remained unaltered.

  20. Anti-amyloidogenic Activity of IgGs Contained in Normal Plasma

    PubMed Central

    Williams, Angela D.; McWilliams-Koeppen, Helen P.; Acero, Luis; Weber, Alfred; Ehrlich, Hartmut; Schwarz, Hans P.; Solomon, Alan

    2010-01-01

    Introduction We have previously shown that a subpopulation of naturally occurring human IgGs has therapeutic potential for the amyloid-associated disorders. These molecules cross-react with conformational epitopes on amyloidogenic assemblies, including amyloid beta (Aβ) protein fibrils that are a pathological hallmark of Alzheimer’s disease. Materials and Methods Using our europium-linked immunosorbant assay, we established that ∼95% of 260 screened donor plasma samples had amyloid fibril-reactive IgGs and Aβ conformer-reactive IgGs with minimal binding to Aβ monomers. Anti-amyloidogenic reactivity was diverse and attributed to Aβ targeting multiple fibril-related binding sites and/or variations in multidentate binding. Results and Discussion There was no correlation between anti-fibril and anti-oligomer reactivity and donor age (19 to 60 years old) or gender. These findings demonstrate the inherent but diverse anti-amyloidogenic activity of natural IgGs contained in normal plasma. Conclusion Our studies provide support for investigating the clinical significance and physiological function of this novel class of antibodies. PMID:20405179

  1. Estrogen effects on thyroid iodide uptake and thyroperoxidase activity in normal and ovariectomized rats.

    PubMed

    Lima, Lívia P; Barros, Inês A; Lisbôa, Patrícia C; Araújo, Renata L; Silva, Alba C M; Rosenthal, Doris; Ferreira, Andrea C F; Carvalho, Denise P

    2006-08-01

    Sex steroids interfere with the pituitary-thyroid axis function, although the reports have been controversial and no conclusive data is available. Some previous reports indicate that estradiol might also regulate thyroid function through a direct action on the thyrocytes. In this report, we examined the effects of low and high doses of estradiol administered to control and ovariectomized adult female rats and to pre-pubertal females. We demonstrate that estradiol administration to both intact adult and pre-pubertal females causes a significant increase in the relative thyroid weight. Serum T3 is significantly decreased in ovariectomized rats, and is normalized by estrogen replacement. Neither doses of estrogen produced a significant change in serum TSH and total T4 in ovariectomized, adult intact and pre-pubertal rats. The highest, supraphysiological, estradiol dose produced a significant increase in thyroid iodide uptake in ovariectomized and in pre-pubertal rats, but not in control adult females. Thyroperoxidase activity was significantly higher in intact adult rats treated with both estradiol doses and in ovariectomized rats treated with the highest estradiol dose. Since serum TSH levels were not significantly changed, we suggest a direct action of estradiol on the thyroid gland, which depends on the age and on the previous gonad status of the animal. PMID:16762383

  2. Influences of NREM sleep on activity of palatoglossus and levator palatini muscles in normal men.

    PubMed

    Tangel, D J; Mezzanotte, W S; White, D P

    1995-02-01

    Most evidence indicates that palatal position has an important influence on respiration during sleep. We have previously demonstrated during wakefulness that the levator palatini (LP) and the palatoglossus (PG) muscles function in an integrated manner in determining the route of respiration. In this study we first determined the effect of non-rapid-eye-movement (NREM) sleep on LP and PG electromyograms (EMGs) and then assessed if subjects could switch from nasal (NR) to oral (OR) respiration during NREM sleep without arousal. Six normal males subjects were studied using intramuscular EMG recording electrodes (LP and PG) and a divided mask to separate NR and OR. Peak inspiratory and end-expiratory EMGs of the LP fell significantly during NREM sleep [3.7 +/- 0.4 (SE), 1.9 +/- 0.4, and 2.4 +/- 0.7 arbitrary units for LP peak inspiratory awake, stage 2, and stage 3/4, respectively; 2.7 +/- 0.2, 1.5 +/- 0.2, and 1.8 +/- 0.5 arbitrary units for LP end-expiratory awake, stage 2, and stage 3/4, respectively; P < 0.05]. In a similar manner, the peak inspiratory EMG of the PG fell from wakefulness to stage 2 NREM sleep [5.1 +/- 0.5 and 3.9 +/- 0.5 arbitrary units for PG peak inspiratory awake and stage 2, respectively]. On the other hand, the PG peak inspiratory activity returned to near waking levels during stage 3/4 sleep, with the PG end-expiratory activity never falling during sleep. A total of 14 nasal occlusions were performed during NREM sleep. In all cases except one, an arousal was required to institute a change to OR.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Normal inhibitory avoidance learning and anxiety, but increased locomotor activity in mice devoid of PrP(C).

    PubMed

    Roesler, R; Walz, R; Quevedo, J; de-Paris, F; Zanata, S M; Graner, E; Izquierdo, I; Martins, V R; Brentani, R R

    1999-08-25

    Prions are the causative agents of transmissible spongiform encephalopathies. The transmissible agent (PrP(Sc)) is an abnormal form of PrP(C), a normal neuronal protein. The physiological role of PrP(C) remains unclear. In the present report, we evaluated behavioral parameters in Prnp(0/0) mice devoid of PrP(C). Prnp(0/0) mice showed normal short- and long-term retention of a step-down inhibitory avoidance task and normal behavior in an elevated plus maze test of anxiety. During a 5-min exploration of an open field, Prnp(0/0) mice showed normal number of rearings, defecation, and latency to initiate locomotion, but a significant increase in the number of crossings. The results suggest that Prnp(0/0) mice show normal fear-motivated memory, anxiety and exploratory behavior, and a slight increase in locomotor activity during exploration of a novel environment.

  4. FMRI Brain Activation in a Finnish Family with Specific Language Impairment Compared with a Normal Control Group

    ERIC Educational Resources Information Center

    Hugdahl, Kenneth; Gundersen, Hilde; Brekke, Cecilie; Thomsen, Tormod; Rimol, Lars Morten; Ersland, Lars; Niemi, Jussi

    2004-01-01

    The aim of the present study was to investigate differences in brain activation in a family with SLI as compared to intact individuals with normally developed language during processing of language stimuli. Functional magnetic resonance imaging (fMRI) was used to monitor changes in neuronal activation in temporal and frontal lobe areas in 5…

  5. Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Wysocki, Gerard (Inventor); Tittel, Frank K. (Inventor); Curl, Robert F. (Inventor)

    2010-01-01

    A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claim 1 wherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

  6. Proliferating cell nuclear antigen (PCNA) activity in hepatocellular carcinoma, benign peri-neoplastic and normal liver.

    PubMed

    Mun, Kein-Seong; Cheah, Phaik-Leng; Baharudin, Nurul Bahiyah; Looi, Lai-Meng

    2006-12-01

    Hepatocellular carcinoma (HCC) is among the ten most common cancers in Malaysian males. As cellular proliferation is an important feature of malignant transformation, we studied the proliferation pattern of normal and benign perineoplastic liver versus hepatocellular carcinoma in an attempt to further understand the tumour transformation process. 39 HCC (21 with accompanying and 18 without cirrhosis) histologically diagnosed at the Department of Pathology, University of Malaya Medical Centre between January 1992 and December 2003 were immunohistochemically studied using a monoclonal antibody to PCNA (Clone PC10: Dako). 20 livers from cases who had succumbed to traumatic injuries served as normal liver controls (NL). PCNA labeling index (PCNA-LI) was determined by counting the number of immunopositive cells in 1000 contiguous HCC, benign cirrhotic perineoplastic liver (BLC), benign perineoplastic non-cirrhotic (BLNC) and NL cells and conversion to a percentage. The PCNA-LI was also expressed as Ojanguren et al's grades. PCNA was expressed in 10% NL, 38.9% BLNC, 76.2% BLC and 71.8% HCC with BLNC, BLC and HCC showing significantly increased (p < 0.05) number of cases which expressed PCNA compared with NL. The number of BLC which expressed PCNA was also significantly increased compared with BLNC. PCNA-LI ranged from 0-2.0% (mean = 0.2%) in NL, 0-2.0% (mean = 0.3%) in BLNC, 0-3.6% (mean = 0.7%) in BLC and 0-53.8% (mean = 7.6%) in HCC with PCNA-LI significantly increased (p < 0.05) only in HCC compared with BLC, BLNC and NL. Accordingly, all NL, BLC and BLNC showed minimal (<5% cells being immunopositive) immunoreactivity on Ojanguren et al's grading system and only HCC demonstrated immunoreactivity which ranged up to grade 3 (75% of cells). From this study, there appears to be a generally increasing trend of proliferative activity from NL to BLNC to BLC and HCC. Nonetheless, BLNC and BLC, like NL, retained low PCNA-LI and only HCC had a significantly increased PCNA

  7. PCNA immunoreactivity revealing normal proliferative activity in the brain of an adult Elasmobranch, Torpedo marmorata.

    PubMed

    Margotta, Vito

    2007-01-01

    The brain of adult heterothermic vertebrates can be already provided of quiescent cells, scattered ("matrix cells") and/or clustered ("matrix areas"). These typical cells, in some regions located at or near ventricular surfaces and at peri-ependymal layers, in other territories populating their framework, maintain some embryonic properties and are responsible of normal or variously experimentally induced proliferative activities. On these topics there are a great number of reports concerning Teleostean Osteichthyes, Urodele and Anuran Amphibians, Lacertilian Reptiles. At the contrary, only few are the contributions regarding the Petromyzontidae. Involving an immunocytochemical marker, the Proliferating Cell Nuclear Antigen (PCNA), revealing proliferative events, in the last years we have undertaken a reappraisal focused on these encephalic performances in normal adult poikilothermal vertebrates. To provide a valid comparison between our results and the literature data, our choice of the specimens was based on the desire to employ organisms belonging to the same or phylogenetically close species used by previous Authors in similar studies. In our immunocytochemical panorama there is a substantial agreement between our contributions and bibliographic references concerning natural encephalic proliferative phenomena in these vertebrates. At this point of our study, the last missing piece was represented by the Chondrichthyes about which the literature data are lacking. In order to fill this gap, the aim of the present research is to investigate, involving the same PCNA test, whether proliferative events also persist in the brain of adult cartilaginous fishes. The immunostaining images obtained in the Elasmo branch Torpedo marmorata, well-known for the emission of high electrical discharges, exhibit undifferentiated cells in relationship with the ependymal epithelium lining the cavities of all cerebral districts; some other neuroblasts are scattered in the mesencephalic

  8. Observations of the azimuthal dependence of normal mode coupling below 4 mHz at the South Pole and its nearby stations: Insights into the anisotropy beneath the Transantarctic Mountains

    NASA Astrophysics Data System (ADS)

    Hu, Xiao Gang

    2016-08-01

    Normal mode coupling pair 0S26-0T26 and 0S27-0T27 are significantly present at the South Pole station QSPA after the 2011/03/11 Mw9.1 Tohoku earthquake. In an attempt to determine the mechanisms responsible for the coupling pairs, I first investigate mode observations at 43 stations distributed along the polar great-circle path for the earthquake and observations at 32 Antarctic stations. I rule out the effect of Earth's rotation as well as the effect of global large-scale lateral heterogeneity, but argue instead for the effect of small-scale local azimuthal anisotropy in a depth extent about 300 km. The presence of quasi-Love waveform in 2-5 mHz at QSPA and its nearby stations confirms the predication. Secondly, I analyze normal mode observations at the South Pole location after 28 large earthquakes from 1998 to 2015. The result indicates that the presence of the mode coupling is azimuthal dependent, which is related to event azimuths in -46° to -18°. I also make a comparison between the shear-wave splitting measurements of previous studies and the mode coupling observations of this study, suggesting that their difference can be explained by a case that the anisotropy responsible for the mode coupling is not just below the South Pole location but located below region close to the Transantarctic Mountains (TAM). Furthermore, more signals of local azimuthal anisotropy in normal-mode observations at QSPA and SBA, such as coupling of 0S12-0T11 and vertical polarization anomaly for 0T10, confirms the existence of deep anisotropy close to TAM, which may be caused by asthenospheric mantle flow and edge convection around cratonic keel of TAM.

  9. Unconventional Bifunctional Lewis-Brønsted Acid Activation Mode in Bicyclic Guanidine-Catalyzed Conjugate Addition Reactions.

    PubMed

    Cho, Bokun; Wong, Ming Wah

    2015-08-18

    DFT calculations have demonstrated that the unconventional bifunctional Brønsted-Lewis acid activation mode is generally applicable to a range of nucleophilic conjugate additions catalyzed by bicyclic guanidine catalysts. It competes readily with the conventional bifunctional Brønsted acid mode of activation. The optimal pro-nucleophiles for this unconventional bifunctional activation are acidic substrates with low pKa, while the best electrophiles are flexible 1,4-diamide and 1,4-diester conjugated systems.

  10. Does greater low frequency EEG activity in normal immaturity and in children with epilepsy arise in the same neuronal network?

    PubMed

    Michels, L; Bucher, K; Brem, S; Halder, P; Lüchinger, R; Liechti, M; Martin, E; Jeanmonod, D; Kröll, J; Brandeis, D

    2011-03-01

    Greater low frequency power (<8 Hz) in the electroencephalogram (EEG) at rest is normal in the immature developing brain of children when compared to adults. Children with epilepsy also have greater low frequency interictal resting EEG activity. Whether these power elevations reflect brain immaturity due to a developmental lag or the underlying epileptic pathophysiology is unclear. The present study addresses this question by analyzing spectral EEG topographies and sources for normally developing children and children with epilepsy. We first compared the resting EEG of healthy children to that of healthy adults to isolate effects related to normal brain immaturity. Next, we compared the EEG from 10 children with generalized cryptogenic epilepsy to the EEG of 24 healthy children to isolate effects related to epilepsy. Spectral analysis revealed that global low (delta: 1-3 Hz, theta: 4-7 Hz), medium (alpha: 8-12 Hz) and high (beta: 13-25 Hz) frequency EEG activity was greater in children without epilepsy compared to adults, and even further elevated for children with epilepsy. Topographical and tomographic EEG analyses showed that normal immaturity corresponded to greater delta and theta activity at fronto-central scalp and brain regions, respectively. In contrast, the epilepsy-related activity elevations were predominantly in the alpha band at parieto-occipital electrodes and brain regions, respectively. We conclude that lower frequency activity can be a sign of normal brain immaturity or brain pathology depending on the specific topography and frequency of the oscillating neuronal network. PMID:20820898

  11. Learning about Modes in Atomic Force Microscopy by Means of Hands-On Activities Based on a Simple Apparatus

    ERIC Educational Resources Information Center

    Phuapaiboon, Unchada; Panijpan, Bhinyo; Osotchan, Tanakorn

    2009-01-01

    This study was conducted to examine the results of using a low-cost hands-on setup in combination with accompanying activities to promote understanding of the contact mode of atomic force microscopy (AFM). This contact mode setup enabled learners to study how AFM works by hand scanning using probing cantilevers with different characteristics on…

  12. Bioluminescence Imaging of β Cells and Intrahepatic Insulin Gene Activity under Normal and Pathological Conditions

    PubMed Central

    Sekiguchi, Yukari; Nagasaki, Haruka; Daassi, Dhouha; Tai, Pei-Han; Ema, Masatsugu; Kudo, Takashi; Takahashi, Satoru

    2013-01-01

    In diabetes research, bioluminescence imaging (BLI) has been applied in studies of β-cell impairment, development, and islet transplantation. To develop a mouse model that enables noninvasive imaging of β cells, we generated a bacterial artificial chromosome (BAC) transgenic mouse in which a mouse 200-kbp genomic fragment comprising the insulin I gene drives luciferase expression (Ins1-luc BAC transgenic mouse). BLI of mice was performed using the IVIS Spectrum system after intraperitoneal injection of luciferin, and the bioluminescence signal from the pancreatic region analyzed. When compared with MIP-Luc-VU mice [FVB/N-Tg(Ins1-luc)VUPwrs/J] expressing luciferase under the control of the 9.2-kbp mouse insulin I promoter (MIP), the bioluminescence emission from Ins1-luc BAC transgenic mice was enhanced approximately 4-fold. Streptozotocin-treated Ins1-luc BAC transgenic mice developed severe diabetes concomitant with a sharp decline in the BLI signal intensity in the pancreas. Conversely, mice fed a high-fat diet for 8 weeks showed an increase in the signal, reflecting a decrease or increase in the β-cell mass. Although the bioluminescence intensity of the islets correlated well with the number of isolated islets in vitro, the intensity obtained from a living mouse in vivo did not necessarily reflect an absolute quantification of the β-cell mass under pathological conditions. On the other hand, adenovirus-mediated gene transduction of β-cell-related transcription factors in Ins1-luc BAC transgenic mice generated luminescence from the hepatic region for more than 1 week. These results demonstrate that BLI in Ins1-luc BAC transgenic mice provides a noninvasive method of imaging islet β cells and extrapancreatic activity of the insulin gene in the liver under normal and pathological conditions. PMID:23593212

  13. The Negative Mode Proteome with Activated Ion Negative Electron Transfer Dissociation (AI-NETD)*

    PubMed Central

    Riley, Nicholas M.; Rush, Matthew J. P.; Rose, Christopher M.; Richards, Alicia L.; Kwiecien, Nicholas W.; Bailey, Derek J.; Hebert, Alexander S.; Westphall, Michael S.; Coon, Joshua J.

    2015-01-01

    The field of proteomics almost uniformly relies on peptide cation analysis, leading to an underrepresentation of acidic portions of proteomes, including relevant acidic posttranslational modifications. Despite the many benefits negative mode proteomics can offer, peptide anion analysis remains in its infancy due mainly to challenges with high-pH reversed-phase separations and a lack of robust fragmentation methods suitable for peptide anion characterization. Here, we report the first implementation of activated ion negative electron transfer dissociation (AI-NETD) on the chromatographic timescale, generating 7,601 unique peptide identifications from Saccharomyces cerevisiae in single-shot nLC-MS/MS analyses of tryptic peptides—a greater than 5-fold increase over previous results with NETD alone. These improvements translate to identification of 1,106 proteins, making this work the first negative mode study to identify more than 1,000 proteins in any system. We then compare the performance of AI-NETD for analysis of peptides generated by five proteases (trypsin, LysC, GluC, chymotrypsin, and AspN) for negative mode analyses, identifying as many as 5,356 peptides (1,045 proteins) with LysC and 4,213 peptides (857 proteins) with GluC in yeast—characterizing 1,359 proteins in total. Finally, we present the first deep-sequencing approach for negative mode proteomics, leveraging offline low-pH reversed-phase fractionation prior to online high-pH separations and peptide fragmentation with AI-NETD. With this platform, we identified 3,467 proteins in yeast with trypsin alone and characterized a total of 3,730 proteins using multiple proteases, or nearly 83% of the expressed yeast proteome. This work represents the most extensive negative mode proteomics study to date, establishing AI-NETD as a robust tool for large-scale peptide anion characterization and making the negative mode approach a more viable platform for future proteomic studies. PMID:26193884

  14. Antiviral activity and specific modes of action of bacterial prodigiosin against Bombyx mori nucleopolyhedrovirus in vitro.

    PubMed

    Zhou, Wei; Zeng, Cheng; Liu, RenHua; Chen, Jie; Li, Ru; Wang, XinYan; Bai, WenWen; Liu, XiaoYuan; Xiang, TingTing; Zhang, Lin; Wan, YongJi

    2016-05-01

    Prodigiosin, the tripyrrole red pigment, is a bacterial secondary metabolite with multiple bioactivities; however, the antiviral activity has not been reported yet. In the present study, we found the antiviral activity of bacterial prodigiosin on Bombyx mori nucleopolyhedrovirus (BmNPV)-infected cells in vitro, with specific modes of action. Prodigiosin at nontoxic concentrations selectively killed virus-infected cells, inhibited viral gene transcription, especially viral early gene ie-1, and prevented virus-mediated membrane fusion. Under prodigiosin treatment, both progeny virus production and viral DNA replication were significantly inhibited. Fluorescent assays showed that prodigiosin predominantly located in cytoplasm which suggested it might interact with cytoplasm factors to inhibit virus replication. In conclusion, the present study clearly indicates that prodigiosin possesses significant antiviral activity against BmNPV.

  15. Dynamic Multiscale Modes of Resting State Brain Activity Detected by Entropy Field Decomposition.

    PubMed

    Frank, Lawrence R; Galinsky, Vitaly L

    2016-09-01

    The ability of functional magnetic resonance imaging (FMRI) to noninvasively measure fluctuations in brain activity in the absence of an applied stimulus offers the possibility of discerning functional networks in the resting state of the brain. However, the reconstruction of brain networks from these signal fluctuations poses a significant challenge because they are generally nonlinear and nongaussian and can overlap in both their spatial and temporal extent. Moreover, because there is no explicit input stimulus, there is no signal model with which to compare the brain responses. A variety of techniques have been devised to address this problem, but the predominant approaches are based on the presupposition of statistical properties of complex brain signal parameters, which are unprovable but facilitate the analysis. In this article, we address this problem with a new method, entropy field decomposition, for estimating structure within spatiotemporal data. This method is based on a general information field-theoretic formulation of Bayesian probability theory incorporating prior coupling information that allows the enumeration of the most probable parameter configurations without the need for unjustified statistical assumptions. This approach facilitates the construction of brain activation modes directly from the spatial-temporal correlation structure of the data. These modes and their associated spatial-temporal correlation structure can then be used to generate space-time activity probability trajectories, called functional connectivity pathways, which provide a characterization of functional brain networks. PMID:27391678

  16. Evidence for a Clathrin-independent mode of endocytosis at a continuously active sensory synapse.

    PubMed

    Fuchs, Michaela; Brandstätter, Johann Helmut; Regus-Leidig, Hanna

    2014-01-01

    Synaptic vesicle exocytosis at chemical synapses is followed by compensatory endocytosis. Multiple pathways including Clathrin-mediated retrieval of single vesicles, bulk retrieval of large cisternae, and kiss-and-run retrieval have been reported to contribute to vesicle recycling. Particularly at the continuously active ribbon synapses of retinal photoreceptor and bipolar cells, compensatory endocytosis plays an essential role to provide ongoing vesicle supply. Yet, little is known about the mechanisms that contribute to endocytosis at these highly complex synapses. To identify possible specializations in ribbon synaptic endocytosis during different states of activity, we exposed mice to controlled lighting conditions and compared the distribution of endocytotic proteins at rod and cone photoreceptor, and ON bipolar cell ribbon synapses with light and electron microscopy. In mouse ON bipolar cell terminals, Clathrin-mediated endocytosis seemed to be the dominant mode of endocytosis at all adaptation states analyzed. In contrast, in mouse photoreceptor terminals in addition to Clathrin-coated pits, clusters of membranously connected electron-dense vesicles appeared during prolonged darkness. These clusters labeled for Dynamin3, Endophilin1, and Synaptojanin1, but not for AP180, Clathrin LC, and hsc70. We hypothesize that rod and cone photoreceptors possess an additional Clathrin-independent mode of vesicle retrieval supporting the continuous synaptic vesicle supply during prolonged high activity.

  17. Distribution of deformation on an active normal fault network, NW Corinth Rift

    NASA Astrophysics Data System (ADS)

    Ford, Mary; Meyer, Nicolas; Boiselet, Aurélien; Lambotte, Sophie; Scotti, Oona; Lyon-Caen, Hélène; Briole, Pierre; Caumon, Guillaume; Bernard, Pascal

    2013-04-01

    Over the last 20-25 years, geodetic measurements across the Gulf of Corinth have recorded high extension rates varying from 1.1 cm/a in the east to a maximum of 1.6 cm/a in the west. Geodetic studies also show that current deformation is confined between two relatively rigid blocks defined as Central Greece (to the north) and the Peloponnesus to the south. Active north dipping faults (<1 Ma) define the south coast of the subsiding Gulf, while high seismicity (major earthquakes and micro-seismicity) is concentrated at depth below and to the north of the westernmost Gulf. How is this intense deformation distributed in the upper crust? Our objectives here are (1) to propose two models for the distribution of deformation in the upper crust in the westernmost rift since 1 Ma, and (2) to place the tectonic behaviour of the western Gulf in the context of longer term rift evolution. Over 20 major active normal faults have been identified in the CRL area based specific characteristics (capable of generating earthquakes M> 5.5, active in the last 1 M yrs, slip rate >0.5 mm/a). Because of the uncertainty related to fault geometry at depth two models for 3D fault network geometry in the western rift down to 10 km were constructed using all available geophysical and geological data. The first model assumes planar fault geometries while the second uses listric geometries for major faults. A model for the distribution of geodetically-defined extension on faults is constructed along five NNE-SSW cross sections using a variety of data and timescales. We assume that the role of smaller faults in accommodating deformation is negligible so that extension is fully accommodated on the identified major faults. Uncertainties and implications are discussed. These models provide estimates of slip rate for each fault that can be used in seismic hazard models. A compilation of onshore and offshore data shows that the western Gulf is the youngest part of the Corinth rift having initiated

  18. Evidence for active creep on the Alto Tiberina low angle normal fault inferred using GPS geodesy

    NASA Astrophysics Data System (ADS)

    Rick, Bennett; Jackson, Lily; Mencin, David; Casale, Gabriele

    2014-05-01

    range ~43.2ºN and 43.5ºN. We also test the regional extent of the fault by extending the fault model to the north and south of the well-imaged portion of the fault, assuming a 20º dip. We estimated fault coupling along-strike and down-dip to assess spatial variations in creep on the model fault. Our modeling suggests that the portion of the model fault in the latitude band ~43.1ºN to ~43.7ºN, encompassing the geophysically imaged ATF fault, creeps at nearly the full fault slip rate of ~2 mm/yr below a depths of 3-5 km. Our model corroborates previous inferences, suggesting active creep at shallow depth on the well-imaged portion of the ATF. However, outside of this range of latitudes, where the existence of a regional low angle normal fault is speculative, the model fault appears to be coupled to greater depths (7-8 km or deeper). Interestingly, the apparent locked zones to the north and south of the creeping zone correlate with the locations of instrumentally recorded large magnitude hanging wall earthquakes. In contrast, there have been no instrumentally recorded large magnitude earthquakes in the hanging wall overlying the creeping portion of the fault.

  19. Antimicrobial Activity of Amine Oxides: Mode of Action and Structure-Activity Correlation

    PubMed Central

    Šubík, Július; Takácsová, Gizela; Pšenák, Mikuláš; Devínsky, Ferdinand

    1977-01-01

    The effect of N-alkyl derivatives of saturated heterocyclic amine oxides on the growth and metabolism of microorganisms has been studied. 4-Dodecylmorpholine-N-oxide inhibited the differentiation and growth of Bacillus cereus, of different species of filamentous fungi, and of the yeast Saccharomyces cerevisiae. For vegetative cells, the effect of 4-dodecylmorpholine-N-oxide was lethal. Cells of S. cerevisiae, after interaction with 4-dodecylmorpholine-N-oxide, released intracellular K+ and were unable to oxidize or ferment glucose. The functions of isolated yeast mitochondria were also impaired. 4-Dodecylmorpholine-N-oxide at growth-inhibiting concentrations induced rapid lysis of osmotically stabilized yeast protoplasts, with the rate of lysis a function of temperature and of amine oxide concentration. A study of the relationships between structure, antimicrobial activity, and cytolytic activity was made with a group of structurally different amine oxides involving a series of homologous 4-alkylmorpholine-N-oxides, 1-alkylpiperidine-N-oxides, 1-dodecylpyrrolidine-N-oxide, 1-dodecylperhydroasepine-N-oxide, and N,N-dimethyldodecylamine oxide. Disorganization of the membrane structure after interaction of cells with the tested amine oxides was primarily responsible for the antimicrobial activity of the amine oxides. This activity was found to be dependent on the chain length of the hydrophobic alkyl group and was only moderately influenced by other substituents of the polarized N-oxide group. PMID:409340

  20. Activities of gamma-glutamyl transpeptidase and erythrocyte glutathione dependent enzymes in nasopharyngeal carcinoma patients and normal controls.

    PubMed

    Ngah, W Z; Shamaan, N A; Said, M H; Azhar, M T

    1993-01-01

    Plasma gamma-glutamyltranspeptidase (gamma-GT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were determined in normal and nasopharyngeal carcinoma (NPC) patients. No difference in enzyme activities was observed in the three major races of the Malaysian population, i.e. Malay, Chinese and Indian patients. However, plasma gamma-GT, erythrocyte glutathione S-transferase (GST) and GPx activities were significantly increased in all NPC patients, while GR activity remained unchanged. Patients with elevated plasma gamma-GT activities also had increased GST and GPx activities. Plasma gamma-GT and GPx activities were then found to be affected by treatment. Patients with plasma gamma-GT activity greater than 70 IU/l had very poor prognoses but patients with decreased gamma-GT activities were found to be in remission.

  1. Methylphenidate remediates error-preceding activation of the default mode brain regions in cocaine addicted individuals

    PubMed Central

    Matuskey, David; Luo, Xi; Zhang, Sheng; Morgan, Peter T.; Abdelghany, Osama; Malison, Robert T.; Li, Chiang-shan R.

    2013-01-01

    Many previous studies suggest the potential of psychostimulants in improving cognitive functioning. Our earlier pharmacological brain imaging study showed that intravenous methylphenidate (MPH) improves inhibitory control by altering cortico-striato-thalamic activations in cocaine dependent (CD) individuals. Here we provide additional evidence for the effects of MPH in restoring cerebral activations during cognitive performance. Ten CD individuals performed a stop signal task (SST) during functional magnetic resonance imaging (fMRI) in two sessions, in which either MPH (0.5 mg/Kg BW) or saline was administered intravenously. In the SST, a frequent go signal instructs participants to make a speeded response and a less frequent stop signal instructs them to withhold the response. Our previous work described increased activation of the precuneus/posterior cingulate cortex and ventromedial prefrontal cortex – regions of the default mode network (DMN) – before participants committed a stop error in healthy control but not CD individuals (Bednarski et al., 2011). The current results showed that, compared to saline, MPH restored error-preceding activations of DMN regions in CD individuals. The extent of the changes in precuneus activity was correlated with MPH-elicited increase in systolic blood pressure. These findings suggest that the influence of MPH on cerebral activations may extend beyond cognitive control and provide additional evidence warranting future studies to investigate the neural mechanisms and physiological markers of the efficacy of agonist therapy in cocaine dependence. PMID:23973363

  2. Variability in the Southern Annular Mode determines wildfire activity in Patagonia

    NASA Astrophysics Data System (ADS)

    Holz, Andrés; Veblen, Thomas T.

    2011-07-01

    Under the current global warming trend, wildfire activity is expected to decrease in biomass-limited fire regimes but increase in drought-limited fire regimes with abundant biomass. We examined the effects of the Southern Annular Mode (SAM) on interannual variability in wildfire activity in xeric woodland and temperate rainforest ecosystems across a latitudinal range of 10° in temperate southwestern South America (SSA). Based on 42 fire history sites based on nearly 600 fire-scarred trees (the largest available dataset of annually resolved tree-ring records of fire activity in the Southern Hemisphere), we show that years of widespread fire in both xeric woodland and rainforest ecosystems are associated with positive departures of SAM. The association of positive SAM with increased fire activity is explained by the teleconnection of SAM to spring drought across most of SSA. During the late 20th century, only the rainforest ecosystem shows a strong increase in fire activity, which is consistent both with upward trends in SAM and with warming conditions. We attribute the lack of increased burning in the xeric woodland environment to socioeconomic factors and fire behavior (low severity) that facilitate more effective fire suppression in the xeric woodland habitat. Given projected future increases in SAM and the associated warm-dry trend, wildfire activity in much of SSA is likely to increase during the 21st century.

  3. Statistics of low-frequency normal-mode amplitudes in an ocean with random sound-speed perturbations: shallow-water environments.

    PubMed

    Colosi, John A; Duda, Timothy F; Morozov, Andrey K

    2012-02-01

    Second- and fourth-moment mode-amplitude statistics for low-frequency ocean sound propagation through random sound-speed perturbations in a shallow-water environment are investigated using Monte Carlo simulations and a transport theory for the cross-mode coherence matrix. The acoustic observables of mean and mean square intensity are presented and the importance of adiabatic effects and cross-mode coherence decay are emphasized. Using frequencies of 200 and 400 Hz, transport theory is compared with Monte Carlo simulations in a canonical shallow-water environment representative of the summer Mid-Atlantic Bight. Except for ranges less than a horizontal coherence length of the sound structure, the intensity moments from the two calculations are in good agreement. Corrections for the short range behavior are presented. For these frequencies the computed mode coupling rates are extremely small, and the propagation is strongly adiabatic with a rapid decay of cross-mode coherence. Coupling effects are predicted to be important at kilohertz frequencies. Decay of cross-mode coherence has important implications for acoustic interactions with nonlinear internal waves: For the case in which the acoustic path is not at glancing incidence with a nonlinear internal-wave front, adiabatic phase randomizing effects lead to a significantly reduced influence of the nonlinear waves on both mean and mean square intensity.

  4. Tectonic Geomorphology of an Active Low-Angle Normal Fault, Sierra El Mayor, Northern Baja California

    NASA Astrophysics Data System (ADS)

    Fletcher, J. M.; Spelz, R.

    2007-05-01

    Low angle normal faults (LANF) are ubiquitously distributed throughout the northern Gulf of California. They commonly bound uplifted mountain ranges and are found in numerous seismic sections in the Altar Desert and Wagner Basin (A. Martin, unpublished data). The Canada David detachment (CDD) is a spectacular example of an active LANF that controls the western mountain front of Sierra El Mayor over a strike length of 60 Km. Like most LANFs, the CDD contains two prominent antiform-synform megamullion pairs that strongly control the tectonic geomorphology of the uplifted footwall block and alluvial terraces along the range flank. Quantitative morphometric analysis along the mountain front shows that drainage basins in antiformal domains have systematically higher outlet elevations, higher gradients, greater relief, and much greater hypsometric integrals. Additionally river valleys are narrower and dominated by bedrock channels that extend nearly to the outlet, which is consistent with the fact that mountain front sinuosity is almost an order of magnitude less in the antiformal domains. A sequence of as many as 8 different regional strath terraces are preserved along the range flank and reconnaissance dating of the deposits by cosmogenic isotopes suggests that they formed during the major interglacial-to-glacial climatic transitions. Strath terraces are generally much older, and relative heights between terraces is significantly lower in synformal domains. All of these geomorphologic characteristics suggest that the synformal domains have experienced much lower rates of uplift and erosion of the footwall and likewise lower rates of sedimentation in the adjacent hanging wall basin. The lack of slip gradients on the master fault between synformal and antiformal domains suggests that the megamullions formed instead by regional buckling perpendicular to the extension direction. A Quaternary scarp array extends along the entire length of the mountain front and also shows

  5. Dual Mode Antibacterial Activity of Ion Substituted Calcium Phosphate Nanocarriers for Bone Infections

    PubMed Central

    Sampath Kumar, T. S.; Madhumathi, K.; Rubaiya, Y.; Doble, Mukesh

    2015-01-01

    Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP) bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA) nanoparticles has been developed. Antibacterial ions such as zinc, silver, and strontium have been incorporated into CDHA at concentrations of 6, 0.25–0.75, and 2.5–7.5 at. %, respectively. The samples were found to be phase pure, acicular nanoparticles of length 40–50 nm and width 5–6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for 5 days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on Staphylococcus aureus and Escherichia coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria, while SrCDHA was weakly active against S. aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity, and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent

  6. Antihyperglycemic and antihyperlipidemic activity of plectranthus amboinicus on normal and alloxan-induced diabetic rats.

    PubMed

    Viswanathaswamy, A H M; Koti, B C; Gore, Aparna; Thippeswamy, A H M; Kulkarni, R V

    2011-03-01

    The present study was undertaken to investigate the antihyperglycemic and antihyperlipidemic effects of ethanol extract of Plectranthus amboinicus in normal and alloxan-induced diabetic rats. Diabetes was induced in Wistar rats by single intraperitoneal administration of alloxan monohydrate (150 mg/kg). Normal as well as diabetic rats were divided into groups (n=6) receiving different treatments. Graded doses (200 mg/kg and 400 mg/kg) of ethanol extract of Plectranthus amboinicus were studied in both normal and alloxan-induced diabetic rats for a period of 15 days. Glibenclamide (600 μg/kg) was used as a reference drug. Oral administration with graded doses of ethanol extract of Plectranthus amboinicus exhibited hypoglycemic effect in normal rats and significantly reduced the peak glucose levels after 120 min of glucose loading. In alloxan-induced diabetic rats, the daily oral treatment with ethanol extract of Plectranthus amboinicus showed a significant reduction in blood glucose. Besides, administration of ethanol extract of Plectranthus amboinicus for 15 days significantly decreased serum contents of total cholesterol, triglycerides whereas HDL-cholesterol, total proteins and calcium were effectively increased. Furthermore, effect of ethanol extract of Plectranthus amboinicus showed profound elevation of serum amylase and reduction of serum lipase. Histology examination showed ethanol extract of Plectranthus amboinicus exhibited almost normalization of damaged pancreatic architecture in rats with diabetes mellitus. Studies clearly demonstrated that ethanol extract of Plectranthus amboinicus leaves possesses hypoglycemic and antihyperlipidemic effects mediated through the restoration of the functions of pancreatic tissues and insulinotropic effect. PMID:22303055

  7. Antihyperglycemic and Antihyperlipidemic Activity of Plectranthus Amboinicus on Normal and Alloxan-Induced Diabetic Rats

    PubMed Central

    Viswanathaswamy, A. H. M.; Koti, B. C.; Gore, Aparna; Thippeswamy, A. H. M.; Kulkarni, R. V.

    2011-01-01

    The present study was undertaken to investigate the antihyperglycemic and antihyperlipidemic effects of ethanol extract of Plectranthus amboinicus in normal and alloxan-induced diabetic rats. Diabetes was induced in Wistar rats by single intraperitoneal administration of alloxan monohydrate (150 mg/kg). Normal as well as diabetic rats were divided into groups (n=6) receiving different treatments. Graded doses (200 mg/kg and 400 mg/kg) of ethanol extract of Plectranthus amboinicus were studied in both normal and alloxan-induced diabetic rats for a period of 15 days. Glibenclamide (600 μg/kg) was used as a reference drug. Oral administration with graded doses of ethanol extract of Plectranthus amboinicus exhibited hypoglycemic effect in normal rats and significantly reduced the peak glucose levels after 120 min of glucose loading. In alloxan-induced diabetic rats, the daily oral treatment with ethanol extract of Plectranthus amboinicus showed a significant reduction in blood glucose. Besides, administration of ethanol extract of Plectranthus amboinicus for 15 days significantly decreased serum contents of total cholesterol, triglycerides whereas HDL-cholesterol, total proteins and calcium were effectively increased. Furthermore, effect of ethanol extract of Plectranthus amboinicus showed profound elevation of serum amylase and reduction of serum lipase. Histology examination showed ethanol extract of Plectranthus amboinicus exhibited almost normalization of damaged pancreatic architecture in rats with diabetes mellitus. Studies clearly demonstrated that ethanol extract of Plectranthus amboinicus leaves possesses hypoglycemic and antihyperlipidemic effects mediated through the restoration of the functions of pancreatic tissues and insulinotropic effect. PMID:22303055

  8. Respiratory burst activity of intestinal macrophages in normal and inflammatory bowel disease.

    PubMed Central

    Mahida, Y R; Wu, K C; Jewell, D P

    1989-01-01

    Macrophages isolated from normal mucosa (greater than 5 cm from tumour) and inflamed mucosa (from patients with inflammatory bowel disease) of colon and ileum were studied for their ability to undergo a respiratory burst as assessed by reduction of nitroblue tetrazolium to formazan. Using phorbol myristate acetate (PMA) and opsonised zymosan as triggers, only a minority (median: 8% for zymosan and 9% for PMA) of macrophages isolated from normal colonic mucosa demonstrated release of oxygen radicals. In contrast, a significantly greater (median: 17% for zymosan and 45% for PMA) proportion of macrophages isolated from inflamed colonic mucosa were able to undergo respiratory burst. Studies with normal and inflamed ileum showed similar results. Stimulation of macrophages isolated from normal colon with interferon-gamma produced only a small increase in the proportion of cells showing release of oxygen radicals. We conclude that the respiratory burst capacity of majority of macrophages isolated from normal colon and ileum is downregulated and a greater proportion of macrophages isolated from inflamed colon and ileum are able to undergo a respiratory burst. Images Fig. 2 PMID:2511088

  9. Growth Factor–dependent Activation of αvβ3 Integrin in Normal Epithelial Cells: Implications for Tumor Invasion

    PubMed Central

    Trusolino, Livio; Serini, Guido; Cecchini, Germana; Besati, Cristina; Ambesi-Impiombato, Francesco Saverio; Marchisio, Pier Carlo; De Filippi, Rosaria

    1998-01-01

    Integrin activation is a multifaceted phenomenon leading to increased affinity and avidity for matrix ligands. To investigate whether cytokines produced during stromal infiltration of carcinoma cells activate nonfunctional epithelial integrins, a cellular system of human thyroid clones derived from normal glands (HTU-5) and papillary carcinomas (HTU-34) was employed. In HTU-5 cells, αvβ3 integrin was diffused all over the membrane, disconnected from the cytoskeleton, and unable to mediate adhesion. Conversely, in HTU-34 cells, αvβ3 was clustered at focal contacts (FCs) and mediated firm attachment and spreading. αvβ3 recruitment at FCs and ligand-binding activity, essentially identical to those of HTU-34, occurred in HTU-5 cells upon treatment with hepatocyte growth factor/scatter factor (HGF/SF). The HTU-34 clone secreted HGF/SF and its receptor was constitutively tyrosine phosphorylated suggesting an autocrine loop responsible for αvβ3 activated state. Antibody-mediated inhibition of HGF/SF function in HTU-34 cells disrupted αvβ3 enrichment at FCs and impaired adhesion. Accordingly, activation of αvβ3 in normal cells was produced by HTU-34 conditioned medium on the basis of its content of HGF/SF. These results provide the first example of a growth factor–driven integrin activation mechanism in normal epithelial cells and uncover the importance of cytokine-based autocrine loops for the physiological control of integrin activation. PMID:9722624

  10. Plasma Modes

    NASA Astrophysics Data System (ADS)

    Dubin, D. H. E.

    This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.

  11. Tuning sensitivity of CAR to EGFR density limits recognition of normal tissue while maintaining potent anti-tumor activity

    PubMed Central

    Caruso, Hillary G.; Hurton, Lenka V.; Najjar, Amer; Rushworth, David; Ang, Sonny; Olivares, Simon; Mi, Tiejuan; Switzer, Kirsten; Singh, Harjeet; Huls, Helen; Lee, Dean A.; Heimberger, Amy B.; Champlin, Richard E.; Cooper, Laurence J. N.

    2015-01-01

    Many tumors over express tumor-associated antigens relative to normal tissue, such as epidermal growth factor receptor (EGFR). This limits targeting by human T cells modified to express chimeric antigen receptors (CARs) due to potential for deleterious recognition of normal cells. We sought to generate CAR+ T cells capable of distinguishing malignant from normal cells based on the disparate density of EGFR expression by generating two CARs from monoclonal antibodies which differ in affinity. T cells with low affinity Nimo-CAR selectively targeted cells over-expressing EGFR, but exhibited diminished effector function as the density of EGFR decreased. In contrast, the activation of T cells bearing high affinity Cetux-CAR was not impacted by the density of EGFR. In summary, we describe the generation of CARs able to tune T-cell activity to the level of EGFR expression in which a CAR with reduced affinity enabled T cells to distinguish malignant from non-malignant cells. PMID:26330164

  12. Rotation in a reversed field pinch with active feedback stabilization of resistive wall modes

    NASA Astrophysics Data System (ADS)

    Cecconello, M.; Menmuir, S.; Brunsell, P. R.; Kuldkepp, M.

    2006-09-01

    Active feedback stabilization of multiple resistive wall modes (RWMs) has been successfully proven in the EXTRAP T2R reversed field pinch. One of the features of plasma discharges operated with active feedback stabilization, in addition to the prolongation of the plasma discharge, is the sustainment of the plasma rotation. Sustained rotation is observed both for the internally resonant tearing modes (TMs) and the intrinsic impurity oxygen ions. Good quantitative agreement between the toroidal rotation velocities of both is found: the toroidal rotation is characterized by an acceleration phase followed, after one wall time, by a deceleration phase that is slower than in standard discharges. The TMs and the impurity ions rotate in the same poloidal direction with also similar velocities. Poloidal and toroidal velocities have comparable amplitudes and a simple model of their radial profile reproduces the main features of the helical angular phase velocity. RWMs feedback does not qualitatively change the TMs behaviour and typical phenomena such as the dynamo and the 'slinky' are still observed. The improved sustainment of the plasma and TMs rotation occurs also when feedback only acts on internally non-resonant RWMs. This may be due to an indirect positive effect, through non-linear coupling between TMs and RWMs, of feedback on the TMs or to a reduced plasma-wall interaction affecting the plasma flow rotation. Electromagnetic torque calculations show that with active feedback stabilization the TMs amplitude remains well below the locking threshold condition for a thick shell. Finally, it is suggested that active feedback stabilization of RWMs and current profile control techniques can be employed simultaneously thus improving both the plasma duration and its confinement properties.

  13. Semi-active sliding mode control of vehicle suspension with magneto-rheological damper

    NASA Astrophysics Data System (ADS)

    Zhang, Hailong; Wang, Enrong; Zhang, Ning; Min, Fuhong; Subash, Rakheja; Su, Chunyi

    2015-01-01

    The vehicle semi-active suspension with magneto-rheological damper(MRD) has been a hot topic since this decade, in which the robust control synthesis considering load variation is a challenging task. In this paper, a new semi-active controller based upon the inverse model and sliding mode control (SMC) strategies is proposed for the quarter-vehicle suspension with the magneto-rheological (MR) damper, wherein an ideal skyhook suspension is employed as the control reference model and the vehicle sprung mass is considered as an uncertain parameter. According to the asymptotical stability of SMC, the dynamic errors between the plant and reference systems are used to derive the control damping force acquired by the MR quarter-vehicle suspension system. The proposed modified Bouc-wen hysteretic force-velocity ( F- v) model and its inverse model of MR damper, as well as the proposed continuous modulation (CM) filtering algorithm without phase shift are employed to convert the control damping force into the direct drive current of the MR damper. Moreover, the proposed semi-active sliding mode controller (SSMC)-based MR quarter-vehicle suspension is systematically evaluated through comparing the time and frequency domain responses of the sprung and unsprung mass displacement accelerations, suspension travel and the tire dynamic force with those of the passive quarter-vehicle suspension, under three kinds of varied amplitude harmonic, rounded pulse and real-road measured random excitations. The evaluation results illustrate that the proposed SSMC can greatly suppress the vehicle suspension vibration due to uncertainty of the load, and thus improve the ride comfort and handling safety. The study establishes a solid theoretical foundation as the universal control scheme for the adaptive semi-active control of the MR full-vehicle suspension decoupled into four MR quarter-vehicle sub-suspension systems.

  14. High-quality lowest-frequency normal mode strain observations at the Black Forest Observatory (SW-Germany) and comparison with horizontal broad-band seismometer data and synthetics

    NASA Astrophysics Data System (ADS)

    Zürn, W.; Ferreira, A. M. G.; Widmer-Schnidrig, R.; Lentas, K.; Rivera, L.; Clévédé, E.

    2015-12-01

    We present spectra concentrating on the lowest-frequency normal modes of the Earth obtained from records of the invar-wire strainmeters and STS-1 broad-band seismometers located in the Black Forest Observatory, Germany after the disastrous earthquakes off the NW coast of Sumatra in 2004 and off the coast near Tohoku, Japan in 2011. We compare the spectra to ones obtained from synthetic seismograms computed using a mode summation technique for an anelastic, elliptical, rotating, spherically symmetric Earth model. The synthetics include strain-strain-coupling effects by using coupling coefficients obtained from comparisons between Earth tide signals recorded by the strainmeters and synthetic tidal records. We show that for the low-frequency toroidal and spheroidal modes up to 1 mHz, the strainmeters produce better signal-to-noise ratios than the broad-band horizontal seismometers. Overall, the comparison with the synthetics is satisfactory but not as good as for vertical accelerations. In particular, we demonstrate the high quality of the strainmeter data by showing the Coriolis splitting of toroidal modes for the first time in individual records, the first clear observation of the singlet _2S_1^0 and the detection of the fundamental radial mode 0S0 with good signal-to-noise ratio and with a strain amplitude of 10-11. We also identify the latter mode in a record of the Isabella strainmeter after the great Chilean quake in 1960, the detection of which was missed by the original studies.

  15. Physical Activity of Underweight, Normal Weight and Overweight Polish Adolescents: The Role of Classmate and Teacher Support in Physical Education

    ERIC Educational Resources Information Center

    Kantanista, Adam; Osinski, Wieslaw; Bronikowski, Michal; Tomczak, Maciej

    2013-01-01

    The aim of the study was to investigate the relationships of classmate and teacher support during physical education (PE) lessons on moderate-to-vigorous physical activity of 14-16 year-old students whom were underweight, normal weight and overweight. The cross-sectional sample for the study concerned data from 1702 girls and 1547 boys, recruited…

  16. The psychedelic state induced by ayahuasca modulates the activity and connectivity of the default mode network.

    PubMed

    Palhano-Fontes, Fernanda; Andrade, Katia C; Tofoli, Luis F; Santos, Antonio C; Crippa, Jose Alexandre S; Hallak, Jaime E C; Ribeiro, Sidarta; de Araujo, Draulio B

    2015-01-01

    The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN. PMID:25693169

  17. The brain on art: intense aesthetic experience activates the default mode network

    PubMed Central

    Vessel, Edward A.; Starr, G. Gabrielle; Rubin, Nava

    2012-01-01

    Aesthetic responses to visual art comprise multiple types of experiences, from sensation and perception to emotion and self-reflection. Moreover, aesthetic experience is highly individual, with observers varying significantly in their responses to the same artwork. Combining fMRI and behavioral analysis of individual differences in aesthetic response, we identify two distinct patterns of neural activity exhibited by different sub-networks. Activity increased linearly with observers' ratings (4-level scale) in sensory (occipito-temporal) regions. Activity in the striatum (STR) also varied linearly with ratings, with below-baseline activations for low-rated artworks. In contrast, a network of frontal regions showed a step-like increase only for the most moving artworks (“4” ratings) and non-differential activity for all others. This included several regions belonging to the “default mode network” (DMN) previously associated with self-referential mentation. Our results suggest that aesthetic experience involves the integration of sensory and emotional reactions in a manner linked with their personal relevance. PMID:22529785

  18. The Psychedelic State Induced by Ayahuasca Modulates the Activity and Connectivity of the Default Mode Network

    PubMed Central

    Palhano-Fontes, Fernanda; Andrade, Katia C.; Tofoli, Luis F.; Santos, Antonio C.; Crippa, Jose Alexandre S.; Hallak, Jaime E. C.; Ribeiro, Sidarta; de Araujo, Draulio B.

    2015-01-01

    The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN. PMID:25693169

  19. The psychedelic state induced by ayahuasca modulates the activity and connectivity of the default mode network.

    PubMed

    Palhano-Fontes, Fernanda; Andrade, Katia C; Tofoli, Luis F; Santos, Antonio C; Crippa, Jose Alexandre S; Hallak, Jaime E C; Ribeiro, Sidarta; de Araujo, Draulio B

    2015-01-01

    The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.

  20. Total body calcium by neutron activation analysis in normals and osteoporotic populations: a discriminator of significant bone mass loss

    SciTech Connect

    Ott, S.M.; Murano, R.; Lewellen, T.K.; Nelp, W.B.; Chesnut, C.M.

    1983-10-01

    Measurements of total body calcium by neutron activation (TBC) in 94 normal individuals and 86 osteoporotic patients are reported. The ability of TBC to discriminate normal from osteoporotic females was evaluated with decision analysis. Bone mineral content (BMC) by single-photon absorptiometry was also measured. TBC was higher in males (range 826 to 1363 gm vs 537 to 1054 in females) and correlated with height in all normals. In females over age 55 there was a negative correlation with age. Thus, for normals an algorithm was derived to allow comparison between measured TBC and that predicted by sex, age, and height (TBCp). In the 28 normal females over age 55, the TBC was 764 +/- 115 gm vs. 616 +/- 90 in the osteoporotics. In 63 of the osteoporotic females an estimated height, from tibial length, was used to predict TBC. In normals the TBC/TBCp ratio was 1.00 +/- 0.12, whereas in osteoporotic females it was 0.80 +/- 0.12. A receiver operating characteristic curve showed better discrimination of osteoporosis with TBC/TBCp than with wrist BMC. By using Bayes' theorem, with a 25% prevalence of osteoporosis (estimate for postmenopausal women), the posttest probability of disease was 90% when the TBC/TBCp ratio was less than 0.84. The authors conclude that a low TBC/TBCp ratio is very helpful in determining osteoporosis.

  1. Ubiquitous Expression of MAKORIN-2 in Normal and Malignant Hematopoietic Cells and Its Growth Promoting Activity

    PubMed Central

    Lee, King Yiu; Chan, Kathy Yuen Yee; Tsang, Kam Sze; Chen, Yang Chao; Kung, Hsiang-fu; Ng, Pak Cheung; Li, Chi Kong; Leung, Kam Tong; Li, Karen

    2014-01-01

    Makorin-2 (MKRN2) is a highly conserved protein and yet its functions are largely unknown. We investigated the expression levels of MKRN2 and RAF1 in normal and malignant hematopoietic cells, and leukemia cell lines. We also attempted to delineate the role of MKRN2 in umbilical cord blood CD34+ stem/progenitor cells and K562 cell line by over-expression and inhibition of MKRN2 through lentivirus transduction and shRNA nucleofection, respectively. Our results provided the first evidence on the ubiquitous expression of MKRN2 in normal hematopoietic cells, embryonic stem cell lines, primary leukemia and leukemic cell lines of myeloid, lymphoid, erythroid and megakaryocytic lineages. The expression levels of MKRN2 were generally higher in primary leukemia samples compared with those in age-matched normal BM cells. In all leukemia subtypes, there was no significant correlation between expression levels of MKRN2 and RAF1. sh-MKRN2-silenced CD34+ cells had a significantly lower proliferation capacity and decreased levels of the early stem/progenitor subpopulation (CFU-GEMM) compared with control cultures. Over-expression of MKRN2 in K562 cells increased cell proliferation. Our results indicated possible roles of MKRN2 in normal and malignant hematopoiesis. PMID:24675897

  2. Semi-active damping with negative stiffness for multi-mode cable vibration mitigation: approximate collocated control solution

    NASA Astrophysics Data System (ADS)

    Weber, F.; Distl, H.

    2015-11-01

    This paper derives an approximate collocated control solution for the mitigation of multi-mode cable vibration by semi-active damping with negative stiffness based on the control force characteristics of clipped linear quadratic regulator (LQR). The control parameters are derived from optimal modal viscous damping and corrected in order to guarantee that both the equivalent viscous damping coefficient and the equivalent stiffness coefficient of the semi-active cable damper force are equal to their desired counterparts. The collocated control solution with corrected control parameters is numerically validated by free decay tests of the first four cable modes and combinations of these modes. The results of the single-harmonic tests demonstrate that the novel approach yields 1.86 times more cable damping than optimal modal viscous damping and 1.87 to 2.33 times more damping compared to a passive oil damper whose viscous damper coefficient is optimally tuned to the targeted mode range of the first four modes. The improvement in case of the multi-harmonic vibration tests, i.e. when modes 1 and 3 and modes 2 and 4 are vibrating at the same time, is between 1.55 and 3.81. The results also show that these improvements are obtained almost independent of the cable anti-node amplitude. Thus, the proposed approximate real-time applicable collocated semi-active control solution which can be realized by magnetorheological dampers represents a promising tool for the efficient mitigation of stay cable vibrations.

  3. Enhancing effects of agelasphin-11 on natural killer cell activities of normal and tumor-bearing mice.

    PubMed

    Kobayashi, E; Motoki, K; Natori, T; Uchida, T; Fukushima, H; Koezuka, Y

    1996-03-01

    Agelasphin-11 (AGL-11), a novel alpha-galactosylceramide isolated from an extract of a marine sponge, Agelas mauritianus, markedly prolonged the life span of mice intraperitoneally inoculated with B16 cells. Since AGL-11 did not show any direct cytotoxic activity against B16 cells, this compound is considered to be a biological response modifier (BRM). We focused on the enhancing effect of this compound on in vivo natural killer (NK) cell activity because several BRMs have already been determined to enhance the in vivo natural killer (NK) cell activity. When we evaluated the enhancing activity of AGL-11 using normal mice, AGL-11 enhanced in vivo NK cell activity more potently than Poly I:C, which is a positive control. In addition, we examined the effect of this compound on the NK cell activity of tumor-bearing mice, and found that AGL-11 recovers the reduced NK cell activity in a tumor-bearing condition to a higher level than that of normal mice. These results suggest that AGL-11 shows antitumor activity by the activation of antitumor effector cells such as NK cells.

  4. Quantitative Profiling of Human Renal UDP-glucuronosyltransferases and Glucuronidation Activity: A Comparison of Normal and Tumoral Kidney Tissues

    PubMed Central

    Margaillan, Guillaume; Rouleau, Michèle; Fallon, John K.; Caron, Patrick; Villeneuve, Lyne; Turcotte, Véronique; Smith, Philip C.; Joy, Melanie S.

    2015-01-01

    Renal metabolism by UDP-glucuronosyltransferase (UGT) enzymes is central to the clearance of many drugs. However, significant discrepancies about the relative abundance and activity of individual UGT enzymes in the normal kidney prevail among reports, whereas glucuronidation in tumoral kidney has not been examined. In this study, we performed an extensive profiling of glucuronidation metabolism in normal (n = 12) and tumor (n = 14) kidneys using targeted mass spectrometry quantification of human UGTs. We then correlated UGT protein concentrations with mRNA levels assessed by quantitative polymerase chain reaction and with conjugation activity for the major renal UGTs. Beyond the wide interindividual variability in expression levels observed among kidney samples, UGT1A9, UGT2B7, and UGT1A6 are the most abundant renal UGTs in both normal and tumoral tissues based on protein quantification. In normal kidney tissues, only UGT1A9 protein levels correlated with mRNA levels, whereas UGT1A6, UGT1A9, and UGT2B7 quantification correlated significantly with their mRNA levels in tumor kidneys. Data support that posttranscriptional regulation of UGT2B7 and UGT1A6 expression is modulating glucuronidation in the kidney. Importantly, our study reveals a significant decreased glucuronidation capacity of neoplastic kidneys versus normal kidneys that is paralleled by drastically reduced UGT1A9 and UGT2B7 mRNA and protein expression. UGT2B7 activity is the most repressed in tumors relative to normal tissues, with a 96-fold decrease in zidovudine metabolism, whereas propofol and sorafenib glucuronidation is decreased by 7.6- and 5.2-fold, respectively. Findings demonstrate that renal drug metabolism is predominantly mediated by UGT1A9 and UGT2B7 and is greatly reduced in kidney tumors. PMID:25650382

  5. Vibrational normal modes and dynamical stability of DNA triplex poly(dA). 2poly(dT): S-type structure is more stable and in better agreement with observations in solution.

    PubMed Central

    Chen, Y Z; Powell, J W; Prohofsky, E W

    1997-01-01

    A normal-mode and statistical mechanical calculation was carried out to determine the vibrational normal modes, contribution of internal fluctuations to the free energy, and hydrogen bond disruption of DNA triplex poly(dA).2poly(dT). The calculation was performed on both the x-ray fiber diffraction model with a N-type sugar conformation, and a newly proposed model with a S-type sugar conformation. Our calculated normal modes for the S-type structure are in better agreement with observed IR spectra for samples in D2O solution. We also find that the contribution of internal fluctuations to free energy, premelting hydrogen bond disruption probability, and hydrogen bond melting temperatures for the Hoogsteen and Watson-Crick hydrogen bonds all show that the S-type structure is dynamically more stable than the N-type structure in a nominal solution environment. Therefore our calculation supports experimental findings that the triplex d(T)n.d(A)nd(T)n most likely adopts a S-type sugar conformation in solution or at high humidity. Our calculations, however, do not preclude the possibility of an N-type conformation at lower humidities. PMID:9138578

  6. Real-Time Monitoring of Platelet Activation Using Quartz Thickness-Shear Mode Resonator Sensors.

    PubMed

    Wu, Huiyan; Zhao, Guangyi; Zu, Hongfei; Wang, James H-C; Wang, Qing-Ming

    2016-02-01

    In this study, quartz thickness-shear mode (TSM) resonator sensors were adopted to monitor the process of platelet activation. Resting platelets adhering to fibrinogen-coated electrodes were activated by different concentrations of thrombin (1, 10, and 100 U/mL), and the corresponding electrical admittance spectra of TSM resonators during this process were recorded. Based on a bilayer-loading transmission line model of TSM resonators, the complex shear modulus (G' + jG″) and the average thickness (hPL) of the platelet monolayer at a series of time points were obtained. Decrease in thrombin concentration from 100 to 1 U/mL shifted all peaks and plateaus in G', G″, and hPL to higher time points, which could be attributed to the partial activation of platelets by low concentrations of thrombin. The peak value of hPL was acquired when platelets presented their typical spherical shape as the first transformation in activation process. The G' peak appeared 10 ∼ 20 min after hPL peak, when some filopods were observed along the periphery of platelets but without obvious cell spreading. As platelet spreading began and continued, G', G″, and hPL decreased, leading to a steady rise of resonance frequency shift of TSM resonator sensors. The results show high reliability and stability of TSM resonator sensors in monitoring the process of platelet activation, revealing an effective method to measure platelet activities in real-time under multiple experimental conditions. The G', G″, and hPL values could provide useful quantitative measures on platelet structure variations in activation process, indicating potential of TSM resonators in characterization of cells during their transformation. PMID:26840731

  7. Duration of activity and mode of action of modafinil: Studies on sleep and wakefulness in humans.

    PubMed

    Turner, C; Belyavin, A J; Nicholson, A N

    2014-07-01

    The duration of activity of modafinil was investigated in healthy male volunteers in two double-blind crossover studies. Mode of action was explored using a statistical model concerned with the relationship between total sleep duration and that of rapid eye movement (REM) sleep. Nocturnal sleep (23:00-07:00) followed by next-day performance (09:00-17:00) was studied in 12 subjects administered 100, 200, 300 mg modafinil and placebo, 0.5 h before bedtime. Performance overnight (19:00-08:45) followed by sleep (09:15-15:15) was studied in nine subjects administered 100, 200, 300, 400 mg modafinil, 300 mg caffeine and placebo at 22:15. Modafinil dose-dependently reduced sleep duration (nocturnal: 200 mg, p<0.05; 300 mg, p<0.001; morning: 300 and 400 mg, p<0.05) and REM sleep (nocturnal: 300 mg; morning: 400 mg; p<0.05). The statistical model revealed that reduced REM sleep was due to alerting activity, with no evidence of direct suppression of REM sleep, suggesting dopaminergic activity. Enhanced performance with modafinil during overnight work varied with dose (200 mg>100 mg; 300, 400 mg>200, 100 mg, caffeine). However, in the study of next-day performance, the enhancement was attenuated at the highest dose (300 mg) by the greater disturbance of prior sleep. These findings indicate that modafinil has a long duration of action, with alerting properties arising predominantly from dopaminergic activity. PMID:24306135

  8. Reconstituted B cell receptor signaling reveals carbohydrate-dependent mode of activation

    PubMed Central

    Villar, Rina F.; Patel, Jinal; Weaver, Grant C.; Kanekiyo, Masaru; Wheatley, Adam K.; Yassine, Hadi M.; Costello, Catherine E.; Chandler, Kevin B.; McTamney, Patrick. M.; Nabel, Gary J.; McDermott, Adrian B.; Mascola, John R.; Carr, Steven A.; Lingwood, Daniel

    2016-01-01

    Activation of immune cells (but not B cells) with lectins is widely known. We used the structurally defined interaction between influenza hemagglutinin (HA) and its cell surface receptor sialic acid (SA) to identify a B cell receptor (BCR) activation modality that proceeded through non-cognate interactions with antigen. Using a new approach to reconstitute antigen-receptor interactions in a human reporter B cell line, we found that sequence-defined BCRs from the human germline repertoire could be triggered by both complementarity to influenza HA and a separate mode of signaling that relied on multivalent ligation of BCR sialyl-oligosaccharide. The latter suggested a new mechanism for priming naïve B cell responses and manifested as the induction of SA-dependent pan-activation by peripheral blood B cells. BCR crosslinking in the absence of complementarity is a superantigen effect induced by some microbial products to subvert production of antigen-specific immune responses. B cell superantigen activity through affinity for BCR carbohydrate is discussed. PMID:27796362

  9. Active and passive mode calibration of the Combined Thermal Epithermal Neutron (CTEN) system

    SciTech Connect

    Veilleux, J. M.

    2002-06-01

    The Combined Thermal/Epithermal Neutron (CTEN) non-destructive assay (NDA) system was designed to assay transuranic waste by employing an induced active neutron interrogation and/or a spontaneous passive neutron measurement. This is the second of two papers, and focuses on the passive mode, relating the net double neutron coincidence measurement to the plutonium mass via the calibration constant. National Institute of Standards and Technology (NIST) calibration standards were used and the results verified with NIST-traceable verification standards. Performance demonstration program (PDP) 'empty' 208-L matrix drum was used for the calibration. The experimentally derived calibration constant was found to be 0.0735 {+-} 0.0059 g {sup 240}Pu effective per unit response. Using this calibration constant, the Waste Isolation Pilot Plant (WIPP) criteria was satisfied with five minute waste assays in the range from 3 to 177g Pu. CTEN also participated in the PDP Cycle 8A blind assay with organic sludge and metal matrices and passed the criteria for accuracy and precision in both assay modes. The WIPP and EPA audit was completed March 1, 2002 and full certification is awaiting the closeout of one finding during the audit. With the successful closeout of the audit, the CTEN system will have shown that it can provide very fast assays (five minutes or less) of waste in the range from the minimum detection limit (about 2 mg Pu) to 177 g Pu.

  10. Increased default mode network activity in socially anxious individuals during reward processing

    PubMed Central

    2014-01-01

    Background Social anxiety has been associated with potentiated negative affect and, more recently, with diminished positive affect. It is unclear how these alterations in negative and positive affect are represented neurally in socially anxious individuals and, further, whether they generalize to non-social stimuli. To explore this, we used a monetary incentive paradigm to explore the association between social anxiety and both the anticipation and consumption of non-social incentives. Eighty-four individuals from a longitudinal community sample underwent functional magnetic resonance imaging (fMRI) while participating in a monetary incentive delay (MID) task. The MID task consisted of alternating cues indicating the potential to win or prevent losing varying amounts of money based on the speed of the participant’s response. We examined whether self-reported levels of social anxiety, averaged across approximately 7 years of data, moderated brain activity when contrasting gain or loss cues with neutral cues during the anticipation and outcome phases of incentive processing. Whole brain analyses and analyses restricted to the ventral striatum for the anticipation phase and the medial prefrontal cortex for the outcome phase were conducted. Results Social anxiety did not associate with differences in hit rates or reaction times when responding to cues. Further, socially anxious individuals did not exhibit decreased ventral striatum activity during anticipation of gains or decreased MPFC activity during the outcome of gain trials, contrary to expectations based on literature indicating blunted positive affect in social anxiety. Instead, social anxiety showed positive associations with extensive regions implicated in default mode network activity (for example, precuneus, posterior cingulate cortex, and parietal lobe) during anticipation and receipt of monetary gain. Social anxiety was further linked with decreased activity in the ventral striatum during anticipation

  11. Motor activity is modulated via different neuronal circuits in rats with chronic liver failure than in normal rats.

    PubMed

    Cauli, Omar; Mlili, Nisrin; Llansola, Marta; Felipo, Vicente

    2007-04-01

    The mechanisms by which liver failure alters motor function remain unclear. It has been suggested that liver disease alters the neuronal circuit between basal ganglia and cortex that modulates motor function. Activation of group I metabotropic glutamate receptors in the nucleus accumbens (NAcc) by injecting (S)-3,5-dihydroxyphenylglycine (DHPG) activates this circuit and induces locomotion We analysed by in vivo brain microdialysis the function of the circuits that modulate motor function in rats with liver failure due to portacaval shunt (PCS). We inserted cannulae in the NAcc and microdialysis probes in the NAcc, ventral pallidum (VP), substantia nigra pars reticulata (SNr), medio-dorsal thalamus (MDT), ventro-medial thalamus (VMT) or prefrontal cortex (PFCx). We injected DHPG in the NAcc and analysed extracellular neurotransmitters concentration in these areas. The results indicate that in control rats DHPG induces locomotion by activating the 'normal' neuronal circuit: NAcc --> VP --> MDT --> PFCx. In PCS rats this circuit is not activated. In PCS rats, DHPG injection activates an 'alternative' circuit: NAcc --> SNr --> VMT --> PFCx. This circuit is not activated in control rats. DHPG injection increases dopamine in the NAcc of control but not of PCS rats, and glutamate in PCS but not in control rats. DHPG-induced increase in dopamine would activate the 'normal' neuronal circuit, while an increase in glutamate would activate the 'alternative' circuit. The identification of the mechanisms responsible for altered motor function and coordination in liver disease would allow designing treatments to improve motor function in patients with hepatic encephalopathy.

  12. Bone speed of sound and physical activity levels of overweight and normal-weight girls and adolescents.

    PubMed

    Yao, Mathew; Ludwa, Izabella; Corbett, Lauren; Klentrou, Panagiota; Bonsu, Peter; Gammage, Kimberley; Falk, Bareket

    2011-02-01

    Bone properties, reflected by speed of sound (SOS), and physical activity levels were examined in overweight (OW) girls (n = 19) and adolescents (n = 22), in comparison with normal-weight (NW) girls (n = 21) and adolescents (n = 13). Moderate-to-vigorous physical activity (MVPA) was higher in NW than in OW in both age groups. Tibial SOS was lower in OW compared with NW in both age groups. MVPA correlated with tibial SOS, once age was partialed out. The results suggest that overweight girls and adolescents are characterized by low tibial SOS, which may be partially attributed to lower physical activity levels.

  13. Default Mode Network Activity Predicts Early Memory Decline in Healthy Young Adults Aged 18-31.

    PubMed

    Nelson, Steven M; Savalia, Neil K; Fishell, Andrew K; Gilmore, Adrian W; Zou, Fan; Balota, David A; McDermott, Kathleen B

    2016-08-01

    Functional magnetic resonance imaging (fMRI) research conducted in healthy young adults is typically done with the assumption that this sample is largely homogeneous. However, studies from cognitive psychology suggest that long-term memory and attentional control begin to diminish in the third decade of life. Here, 100 participants between the ages of 18 and 31 learned Lithuanian translations of English words in an individual differences study using fMRI. Long-term memory ability was operationalized for each participant by deriving a memory score from 3 convergent measures. Age of participant predicted memory score in this cohort. In addition, degree of deactivation during initial encoding in a set of regions occurring largely in the default mode network (DMN) predicted both age and memory score. The current study demonstrates that early memory decline may partially be accounted for by failure to modulate activity in the DMN.

  14. Melatonin ineffective in neuronal ceroid lipofuscinosis patients with fragmented or normal motor activity rhythms recorded by wrist actigraphy.

    PubMed

    Hätönen, T; Kirveskari, E; Heiskala, H; Sainio, K; Laakso, M L; Santavuori, P

    1999-04-01

    Melatonin was tested as a sleeping pill in five patients with neuronal ceroid lipofuscinoses. The single-blind, placebo-controlled study consisted of motor activity recordings, sleep logs, and administration of placebo or melatonin (2.5 or 5 mg). Daily motor activity rhythms were measured by wrist actigraphy during four 7-day periods (baseline, placebo, melatonin 2.5 mg, and melatonin 5 mg). The placebo or melatonin was administered in the evenings for 3 weeks, and the recordings were made during the last week of the 3-week treatment. Sleep logs were kept by the caregivers during the recordings. Based on period analyses, the activity recordings were evaluated to display a normal (24-h) or fragmented rhythm. Three patients had normal motor activity patterns during the baseline recordings, and administration of placebo or melatonin did not affect their rest/activity rhythms. Two patients had abnormally fragmented activity rhythms during the baseline periods, and administration of placebo or melatonin did not induce synchronization. According to the actigraphic data, there were no changes in activity rhythms resulting from administration of melatonin. However, based on the observations, three families reported that melatonin slightly improved the sleep quality of the patients. These controversial findings show the difficulties involved in specifying the role of melatonin in modulating sleep. Thus, we conclude that more evidence is required before the significance of melatonin as a sleeping pill is defined. PMID:10191137

  15. Melatonin ineffective in neuronal ceroid lipofuscinosis patients with fragmented or normal motor activity rhythms recorded by wrist actigraphy.

    PubMed

    Hätönen, T; Kirveskari, E; Heiskala, H; Sainio, K; Laakso, M L; Santavuori, P

    1999-04-01

    Melatonin was tested as a sleeping pill in five patients with neuronal ceroid lipofuscinoses. The single-blind, placebo-controlled study consisted of motor activity recordings, sleep logs, and administration of placebo or melatonin (2.5 or 5 mg). Daily motor activity rhythms were measured by wrist actigraphy during four 7-day periods (baseline, placebo, melatonin 2.5 mg, and melatonin 5 mg). The placebo or melatonin was administered in the evenings for 3 weeks, and the recordings were made during the last week of the 3-week treatment. Sleep logs were kept by the caregivers during the recordings. Based on period analyses, the activity recordings were evaluated to display a normal (24-h) or fragmented rhythm. Three patients had normal motor activity patterns during the baseline recordings, and administration of placebo or melatonin did not affect their rest/activity rhythms. Two patients had abnormally fragmented activity rhythms during the baseline periods, and administration of placebo or melatonin did not induce synchronization. According to the actigraphic data, there were no changes in activity rhythms resulting from administration of melatonin. However, based on the observations, three families reported that melatonin slightly improved the sleep quality of the patients. These controversial findings show the difficulties involved in specifying the role of melatonin in modulating sleep. Thus, we conclude that more evidence is required before the significance of melatonin as a sleeping pill is defined.

  16. Bumblebees minimize control challenges by combining active and passive modes in unsteady winds

    PubMed Central

    Ravi, Sridhar; Kolomenskiy, Dmitry; Engels, Thomas; Schneider, Kai; Wang, Chun; Sesterhenn, Jörn; Liu, Hao

    2016-01-01

    The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight-control and stability challenges. It is critical to understand the strategies insects employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high-fidelity numerical simulations and lower-order modeling to identify the mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Kármán street formed in the wake of a cylinder. Analysis revealed that at lower frequencies in both steady and unsteady winds the bees mediated lateral movement with body roll - typical casting motion. Numerical simulations of a bumblebee in similar conditions permitted the separation of the passive and active components of the flight trajectories. Consequently, we derived simple mathematical models that describe these two motion components. Comparison between the free-flying live and modeled bees revealed a novel mechanism that enables bees to passively ride out high-frequency perturbations while performing active maneuvers at lower frequencies. The capacity of maintaining stability by combining passive and active modes at different timescales provides a viable means for animals and machines to tackle the challenges posed by complex airflows. PMID:27752047

  17. Modulation of western North Pacific tropical cyclone activity by the Atlantic Meridional Mode

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Vecchi, Gabriel A.; Villarini, Gabriele; Murakami, Hiroyuki; Rosati, Anthony; Yang, Xiaosong; Jia, Liwei; Zeng, Fanrong

    2016-05-01

    This study examines the year-to-year modulation of the western North Pacific (WNP) tropical cyclones (TC) activity by the Atlantic Meridional Mode (AMM) using both observations and the Geophysical Fluid Dynamics Laboratory Forecast-oriented Low Ocean Resolution Version of CM2.5 (FLOR) global coupled model. 1. The positive (negative) AMM phase suppresses (enhances) WNP TC activity in observations. The anomalous occurrence of WNP TCs results mainly from changes in TC genesis in the southeastern part of the WNP. 2. The observed responses of WNP TC activity to the AMM are connected to the anomalous zonal vertical wind shear (ZVWS) caused by AMM-induced changes to the Walker circulation. During the positive AMM phase, the warming in the North Atlantic induces strong descending flow in the tropical eastern and central Pacific, which intensifies the Walker cell in the WNP. The intensified Walker cell is responsible for the suppressed (enhanced) TC genesis in the eastern (western) part of the WNP by strengthening (weakening) ZVWS. 3. The observed WNPTC-AMM linkage is examined by the long-term control and idealized perturbations experiment with FLOR-FA. A suite of sensitivity experiments strongly corroborate the observed WNPTC-AMM linkage and underlying physical mechanisms.

  18. In-space technology flight experiments: Middeck 0-gravity Dynamics Experiment (MODE) and Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Venneri, Samuel L.

    1991-01-01

    The topics addressed are covered in viewgraph form. The objective of the Middeck 0-gravity Dynamics Experiment (MODE) programs is to study gravity dependent nonlinearities associated with fluid slosh and truss structure dynamics. MODE provides a reusable facility for on-orbit dynamics testing of small scale test articles in the shirt sleeve environment on the Shuttle middeck. Flight program objective of Middeck Active Control Experiment (MACE) is to study gravity effects on the performance and stability of controlled structures.

  19. Cyclodextrin type dependent host-guest interaction mode with phthalocyanine and their influence on photodynamic activity to cancer.

    PubMed

    Lu, S; Wang, A; Ma, Y J; Xuan, H Y; Zhao, B; Li, X D; Zhou, J H; Zhou, L; Wei, S H

    2016-09-01

    Three host-guest complexes of phthalocyanines (Pc) with α-, β- or γ-cyclodextrins (CDs) were prepared and their interaction modes, reactive oxygen species (ROSs) generation ability and in vitro anticancer activities were studied and compared. After forming complex with CD, the aggregation degree of Pc was greatly decreased and the water solubility and photodynamic activity was sharply increased. Computer modeling results indicated that the interaction modes between Pc and CDs were varied with different kinds of CD. Especially, the complex of Pc and β-CD has superior stability, ROSs generation ability, and anticancer activity to other complexes.

  20. Diatom-Derived Polyunsaturated Aldehydes Activate Cell Death in Human Cancer Cell Lines but Not Normal Cells

    PubMed Central

    Sansone, Clementina; Braca, Alessandra; Ercolesi, Elena; Romano, Giovanna; Palumbo, Anna; Casotti, Raffaella; Francone, Maria; Ianora, Adrianna

    2014-01-01

    Diatoms are an important class of unicellular algae that produce bioactive polyunsaturated aldehydes (PUAs) that induce abortions or malformations in the offspring of invertebrates exposed to them during gestation. Here we compare the effects of the PUAs 2-trans,4-trans-decadienal (DD), 2-trans,4-trans-octadienal (OD) and 2-trans,4-trans-heptadienal (HD) on the adenocarcinoma cell lines lung A549 and colon COLO 205, and the normal lung/brunch epithelial BEAS-2B cell line. Using the viability MTT/Trypan blue assays, we show that PUAs have a toxic effect on both A549 and COLO 205 tumor cells but not BEAS-2B normal cells. DD was the strongest of the three PUAs tested, at all time-intervals considered, but HD was as strong as DD after 48 h. OD was the least active of the three PUAs. The effect of the three PUAs was somewhat stronger for A549 cells. We therefore studied the death signaling pathway activated in A549 showing that cells treated with DD activated Tumor Necrosis Factor Receptor 1 (TNFR1) and Fas Associated Death Domain (FADD) leading to necroptosis via caspase-3 without activating the survival pathway Receptor-Interacting Protein (RIP). The TNFR1/FADD/caspase pathway was also observed with OD, but only after 48 h. This was the only PUA that activated RIP, consistent with the finding that OD causes less damage to the cell compared to DD and HD. In contrast, cells treated with HD activated the Fas/FADD/caspase pathway. This is the first report that PUAs activate an extrinsic apoptotic machinery in contrast to other anticancer drugs that promote an intrinsic death pathway, without affecting the viability of normal cells from the same tissue type. These findings have interesting implications also from the ecological viewpoint considering that HD is one of the most common PUAs produced by diatoms. PMID:24992192

  1. Activation of coagulation after administration of tumor necrosis factor to normal subjects.

    PubMed

    van der Poll, T; Büller, H R; ten Cate, H; Wortel, C H; Bauer, K A; van Deventer, S J; Hack, C E; Sauerwein, H P; Rosenberg, R D; ten Cate, J W

    1990-06-01

    Tumor necrosis factor has been implicated in the activation of blood coagulation in septicemia, a condition commonly associated with intravascular coagulation and disturbances of hemostasis. To evaluate the early dynamics and the route of the in vivo coagulative response to tumor necrosis factor, we performed a controlled study in six healthy men, monitoring the activation of the common and intrinsic pathways of coagulation with highly sensitive and specific radioimmunoassays. Recombinant human tumor necrosis factor, administered as an intravenous bolus injection (50 micrograms per square meter of body-surface area), induced an early and short-lived rise in circulating levels of the activation peptide of factor X, reaching maximal values after 30 to 45 minutes (mean +/- SEM increase after 45 minutes, 34.2 +/- 18.2 percent; tumor necrosis factor vs. saline, P = 0.015). This was followed by a gradual and prolonged increase in the plasma concentration of the prothrombin fragment F1+2, peaking after four to five hours (mean increase after five hours, 348.0 +/- 144.8 percent; tumor necrosis factor vs. saline, P less than 0.0001). These findings signify the formation of factor Xa (activated factor X) and the activation of prothrombin. Activation of the intrinsic pathway could not be detected by a series of measurements of the plasma levels of factor XII, prekallikrein, factor XIIa-C1 inhibitor complexes, kallikrein-C1 inhibitor complexes, and the activation peptide of factor IX. The delay between the maximal activation of factor X and that of prothrombin amounted to several hours, indicating that neutralization of factor Xa activity was slow. We conclude that a single injection of tumor necrosis factor elicits a rapid and sustained activation of the common pathway of coagulation, probably induced through the extrinsic route. Our results suggest that tumor necrosis factor could play an important part in the early activation of the hemostatic mechanism in septicemia.

  2. Long-term stimulation by active epiretinal implants in normal and RCD1 dogs

    NASA Astrophysics Data System (ADS)

    Güven, Dilek; Weiland, James D.; Fujii, Gildo; Mech, Brian V.; Mahadevappa, Manjunatha; Greenberg, Robert; Roizenblatt, Roberto; Qiu, Guanting; La Bree, Laurie; Wang, Xiaopeng; Hinton, David; Humayun, Mark S.

    2005-03-01

    An epiretinal prosthesis, consisting of an extraocular microelectronic stimulator and an intraocular electrode array, was implanted in one eye of three blind and three sighted dogs. Three dogs (2 blind, 1 normal) were stimulated for 120 days, and two dogs (both normal) for 60 and 103 days respectively for 8-10 h/day at levels of 0.1 mC cm-2 and 0.05 mC cm-2, with each stimulus level presented to half of the array. One blind dog was kept as an inactive implant control. During the study period, electroretinograms (ERG) and fundus photographs were recorded. At the end of the study period, the dogs were sacrificed and histological and morphometric evaluation was made of the retina. No inflammatory reaction, neovascularization or hemorrhage was observed during the follow-up examinations. ERGs were unchanged. Stimulus levels used were of sufficient amplitude to elicit cortical evoked potentials. Histological evaluation showed no inflammatory infiltrates or changes in retina morphometry related to electrical stimulation when compared to the unstimulated control eye. Morphometric analysis revealed no consistent differences relating to electrical stimulation. In summary, chronic electrical stimulation of the dog retina at up to 0.1 mC cm-2 with an epiretinal prosthesis does not appear to adversely affect the retina. This study is supported by The Fletcher Jones Foundation, National Eye Institute Grants 1R24EY12893 and EY03040, the Whitaker Foundation and Second Sight Medical Products, Inc.

  3. Expression and activity of L-Myc in normal mouse development.

    PubMed Central

    Hatton, K S; Mahon, K; Chin, L; Chiu, F C; Lee, H W; Peng, D; Morgenbesser, S D; Horner, J; DePinho, R A

    1996-01-01

    To determine the role of L-Myc in normal mammalian development and its functional relationship to other members of the Myc family, we determined the normal patterns of L-myc gene expression in the developing mouse by RNA in situ hybridization and assessed the phenotypic impact of L-Myc deficiency produced through standard gene targeting methodology. L-myc transcripts were detected in the developing kidney and lung as well as in both the proliferative and the differentiative zones of the brain and neural tube. Despite significant expression of L-myc in developing mouse tissue, homozygous null L-myc mice were found to be viable, reproductively competent, and represented in expected frequencies from heterozygous matings. A detailed histological survey of embryonic and adult tissues, characterization of an embryonic neuronal marker, and measurement of cellular proliferation in situ did not reveal any congenital abnormalities. The lack of an apparent phenotype associated with L-Myc deficiency indicates that L-Myc is dispensable for gross morphological development and argues against a unique role for L-Myc in early central nervous system development as had been previously suggested. Although overlapping expression patterns among myc family members raise the possibility of complementation of L-Myc deficiency by other Myc oncoproteins, compensatory changes in the levels of c- and/or N-myc transcripts were not detected in homozygous null L-myc mice. PMID:8657155

  4. Long-term stimulation by active epiretinal implants in normal and RCD1 dogs.

    PubMed

    Güven, Dilek; Weiland, James D; Fujii, Gildo; Mech, Brian V; Mahadevappa, Manjunatha; Greenberg, Robert; Roizenblatt, Roberto; Qiu, Guanting; Labree, Laurie; Wang, Xiaopeng; Hinton, David; Humayun, Mark S

    2005-03-01

    An epiretinal prosthesis, consisting of an extraocular microelectronic stimulator and an intraocular electrode array, was implanted in one eye of three blind and three sighted dogs. Three dogs (2 blind, 1 normal) were stimulated for 120 days, and two dogs (both normal) for 60 and 103 days respectively for 8-10 h/day at levels of 0.1 mC cm(-2) and 0.05 mC cm(-2), with each stimulus level presented to half of the array. One blind dog was kept as an inactive implant control. During the study period, electroretinograms (ERG) and fundus photographs were recorded. At the end of the study period, the dogs were sacrificed and histological and morphometric evaluation was made of the retina. No inflammatory reaction, neovascularization or hemorrhage was observed during the follow-up examinations. ERGs were unchanged. Stimulus levels used were of sufficient amplitude to elicit cortical evoked potentials. Histological evaluation showed no inflammatory infiltrates or changes in retina morphometry related to electrical stimulation when compared to the unstimulated control eye. Morphometric analysis revealed no consistent differences relating to electrical stimulation. In summary, chronic electrical stimulation of the dog retina at up to 0.1 mC cm(-2) with an epiretinal prosthesis does not appear to adversely affect the retina.

  5. Active versus Passive Proprioceptive Straight-Ahead Pointing in Normal Subjects

    ERIC Educational Resources Information Center

    Chokron, Sylvie; Colliot, Pascale; Atzeni, Thierry; Bartolomeo, Paolo; Ohlmann, Theophile

    2004-01-01

    Eighty blindfolded healthy female subjects participated in an active and a passive straight-ahead pointing task to study the estimation of the subjective sagittal middle in the presence or absence of an active haptic exploration. Subjects were to point straight-ahead with their left or right index finger starting from different right- or…

  6. Comparison of functional magnetic resonance imaging in cerebral activation between normal Uygur and Mandarin participants in semantic identification task

    PubMed Central

    Xi, Yan-Ling; Tian, Qing; Tuerxun, Tuerhong; Kaheman, Kuerbannaimu; Jiang, Chun-Hui; Huang, Hai-Xia; Wang, Bao-Lan

    2015-01-01

    Purpose: This study utilized blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) technology to study the activated cerebral regions in normal participants whose native language was Uyghur or Chinese. Methods: We collected the fMRI data from 15 Uyghur-speaking volunteers and 15 Mandarin-speaking volunteers when executing the semantic identification task and compared the results of two groups. Results: Statistically significant difference of brain activation was found primarily in the left anterior cingulate gyrus (BA23) and the midline precuneus (P<0.05). When performing the semantic identification task, the Uyghur group exhibited significant activation in these two regions, whereas the Chinese group demonstrated relatively weak activation in these areas. Conclusion: The cerebral regions activated by Uyghur and Chinese semantic identification are not identical, the dominant hemisphere for both languages is the left cerebral hemisphere. The left anterior cingulate gyrus might have a language function in Uyghur semantic processing. PMID:26550318

  7. Comparison of the activation time effects and the internal energy distributions for the CID, PQD and HCD excitation modes.

    PubMed

    Ichou, Farid; Schwarzenberg, Adrian; Lesage, Denis; Alves, Sandra; Junot, Christophe; Machuron-Mandard, Xavier; Tabet, Jean-Claude

    2014-06-01

    Reproducibility among different types of excitation modes is a major bottleneck in the field of tandem mass spectrometry library development in metabolomics. In this study, we specifically evaluated the influence of collision voltage and activation time parameters on tandem mass spectrometry spectra for various excitation modes [collision-induced dissociation (CID), pulsed Q dissociation (PQD) and higher-energy collision dissociation (HCD)] of Orbitrap-based instruments. For this purpose, internal energy deposition was probed using an approach based on Rice-Rampserger-Kassel-Marcus modeling with three thermometer compounds of different degree of freedom (69, 228 and 420) and a thermal model. This model treats consecutively the activation and decomposition steps, and the survival precursor ion populations are characterized by truncated Maxwell-Boltzmann internal energy distributions. This study demonstrates that the activation time has a significant impact on MS/MS spectra using the CID and PQD modes. The proposed model seems suitable to describe the multiple collision regime in the PQD and HCD modes. Linear relationships between mean internal energy and collision voltage are shown for the latter modes and the three thermometer molecules. These results suggest that a calibration based on the collision voltage should provide reproducible for PQD, HCD to be compared with CID in tandem in space instruments. However, an important signal loss is observed in PQD excitation mode whatever the mass of the studied compounds, which may affect not only parent ions but also fragment ions depending on the fragmentation parameters. A calibration approach for the CID mode based on the variation of activation time parameter is more appropriate than one based on collision voltage. In fact, the activation time parameter in CID induces a modification of the collisional regime and thus helps control the orientation of the fragmentation pathways (competitive or consecutive dissociations).

  8. Broad spectrum antibacterial and antifungal polymeric paint materials: synthesis, structure-activity relationship, and membrane-active mode of action.

    PubMed

    Hoque, Jiaul; Akkapeddi, Padma; Yadav, Vikas; Manjunath, Goutham B; Uppu, Divakara S S M; Konai, Mohini M; Yarlagadda, Venkateswarlu; Sanyal, Kaustuv; Haldar, Jayanta

    2015-01-28

    Microbial attachment and subsequent colonization onto surfaces lead to the spread of deadly community-acquired and hospital-acquired (nosocomial) infections. Noncovalent immobilization of water insoluble and organo-soluble cationic polymers onto a surface is a facile approach to prevent microbial contamination. In the present study, we described the synthesis of water insoluble and organo-soluble polymeric materials and demonstrated their structure-activity relationship against various human pathogenic bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and beta lactam-resistant Klebsiella pneumoniae as well as pathogenic fungi such as Candida spp. and Cryptococcus spp. The polymer coated surfaces completely inactivated both bacteria and fungi upon contact (5 log reduction with respect to control). Linear polymers were more active and found to have a higher killing rate than the branched polymers. The polymer coated surfaces also exhibited significant activity in various complex mammalian fluids such as serum, plasma, and blood and showed negligible hemolysis at an amount much higher than minimum inhibitory amounts (MIAs). These polymers were found to have excellent compatibility with other medically relevant polymers (polylactic acid, PLA) and commercial paint. The cationic hydrophobic polymer coatings disrupted the lipid membrane of both bacteria and fungi and thus showed a membrane-active mode of action. Further, bacteria did not develop resistance against these membrane-active polymers in sharp contrast to conventional antibiotics and lipopeptides, thus the polymers hold great promise to be used as coating materials for developing permanent antimicrobial paint. PMID:25541751

  9. Broad spectrum antibacterial and antifungal polymeric paint materials: synthesis, structure-activity relationship, and membrane-active mode of action.

    PubMed

    Hoque, Jiaul; Akkapeddi, Padma; Yadav, Vikas; Manjunath, Goutham B; Uppu, Divakara S S M; Konai, Mohini M; Yarlagadda, Venkateswarlu; Sanyal, Kaustuv; Haldar, Jayanta

    2015-01-28

    Microbial attachment and subsequent colonization onto surfaces lead to the spread of deadly community-acquired and hospital-acquired (nosocomial) infections. Noncovalent immobilization of water insoluble and organo-soluble cationic polymers onto a surface is a facile approach to prevent microbial contamination. In the present study, we described the synthesis of water insoluble and organo-soluble polymeric materials and demonstrated their structure-activity relationship against various human pathogenic bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and beta lactam-resistant Klebsiella pneumoniae as well as pathogenic fungi such as Candida spp. and Cryptococcus spp. The polymer coated surfaces completely inactivated both bacteria and fungi upon contact (5 log reduction with respect to control). Linear polymers were more active and found to have a higher killing rate than the branched polymers. The polymer coated surfaces also exhibited significant activity in various complex mammalian fluids such as serum, plasma, and blood and showed negligible hemolysis at an amount much higher than minimum inhibitory amounts (MIAs). These polymers were found to have excellent compatibility with other medically relevant polymers (polylactic acid, PLA) and commercial paint. The cationic hydrophobic polymer coatings disrupted the lipid membrane of both bacteria and fungi and thus showed a membrane-active mode of action. Further, bacteria did not develop resistance against these membrane-active polymers in sharp contrast to conventional antibiotics and lipopeptides, thus the polymers hold great promise to be used as coating materials for developing permanent antimicrobial paint.

  10. CDK5 and its activator P35 in normal pituitary and in pituitary adenomas: relationship to VEGF expression.

    PubMed

    Xie, Weiyan; Wang, Hongyun; He, Yue; Li, Dan; Gong, Lei; Zhang, Yazhuo

    2014-01-01

    Pituitary tumors are monoclonal adenomas that account for about 10-15% of intracranial tumors. Cyclin-dependent kinase 5 (CDK5) regulates the activities of various proteins and cellular processes in the nervous system, but its potential roles in pituitary adenomas are poorly understood. The kinase activity of CDK5 requires association with an activating protein, p35 (also known as CDK5 activator 1, p35). Here, we show that functional CDK5, associated with p35, is present in normal human pituitary and in pituitary tumors. Furthermore, p35 mRNA and protein levels were higher in pituitary adenomas than in the normal glands, suggesting that CDK5 activity might be upregulated in pituitary tumors. Inhibition of CDK5 activity in rat pituitary cells, reduced the expression of vascular endothelial growth factor (VEGF), a protein that regulates vasculogenesis and angiogenesis. Our results suggest that increased CDK5-mediated VEGF expression might play a crucial role in the development of pituitary adenomas, and that roscovitine and other CDK5 inhibitors could be useful as anticancer agents. PMID:24550687

  11. CDK5 and Its Activator P35 in Normal Pituitary and in Pituitary Adenomas: Relationship to VEGF Expression

    PubMed Central

    Xie, Weiyan; Wang, Hongyun; He, Yue; Li, Dan; Gong, Lei; Zhang, Yazhuo

    2014-01-01

    Pituitary tumors are monoclonal adenomas that account for about 10-15% of intracranial tumors. Cyclin-dependent kinase 5 (CDK5) regulates the activities of various proteins and cellular processes in the nervous system, but its potential roles in pituitary adenomas are poorly understood. The kinase activity of CDK5 requires association with an activating protein, p35 (also known as CDK5 activator 1, p35). Here, we s