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Sample records for stretch overtone spectra

  1. Spectroscopy of C-H stretching overtones in dimethylacetylene, dimethylcadmium, and dimethylmercury

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares I., C.; Yamasaki, N.L.S.; Weitz, E. (Northwestern Univ., Evanston, IL (USA))

    1989-06-15

    The overtone spectra of a number of C-H stretching vibrations of dimethylacetylene, dimethylcadmium, and dimethylmercury were obtained by using intracavity dye laser photoacoustic spectroscopy. Transitions corresponding to the {Delta}{nu} = 5, 6, and 7 overtones of the C-H stretch are assigned by using the local-mode model. In addition, a number of local-mode-normal-mode combination bands have been identified. Local-mode harmonic frequencies ({omega}{sub e}) and anharmonicities ({omega}{sub e}x{sub e}) are obtained from Birge-Sponer plots. The line widths of the pure local-mode transitions are analyzed in terms of possible resonances with local-mode-normal-mode combination bands. Line widths in this series of compounds are compared to line widths in the M(CH{sub 3}){sub 4} and M(CH{sub 3}){sub 3} series.

  2. Overtone spectra of 1,2-dichloro- and dibromo-ethanes in the near infrared region

    Science.gov (United States)

    Abdul Rasheed, T. M.; Nampoori, V. P. N.; Sathianandan, K.

    1986-10-01

    The vibrational overtone spectra of the liquid phase 1,2-dichloroethane and 1,2-dibromoethane in the spectral regions of the CH stretching local mode overtones corresponding to Δυ CH = 2 to Δυ CH = 5 are reported. The observed spectral features are assigned using the local mode model. Local mode frequencies ω CH and diagonal local model anharmonicities XCH are obtained from an analysis of the spectra. The local-local combinations observed are interpreted on the basis of a coupled CH oscillator model hamiltonian. Local-normal combinations show complex structures and their possible assignments are given.

  3. The 2ν{sub 3} Raman overtone of sulfur hexafluoride: Absolute spectra, pressure effects, and polarizability properties

    Energy Technology Data Exchange (ETDEWEB)

    Chrysos, M., E-mail: michel.chrysos@univ-angers.fr; Rachet, F.; Kremer, D. [LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers (France)

    2014-03-28

    Of the six normal vibrations of SF{sub 6}, ν{sub 3} has a key role in the mechanisms of radiative forcing. This vibration, though inactive in Raman, shows up through the transition 2ν{sub 3} allowing for a complementary view on the asymmetric stretch of the molecule. Here, we look back into this topic, which has already caught some interest in the past but with some points been left out. We make a systematic incoherent-light-scattering analysis of the overtone with the use of different gas pressures and polarization orientations for the incident beam. Absolute-scale isotropic and anisotropic spectra are reported along with natural and pressure-induced widths and shifts, and other spectral features such as the peaks corresponding to the (experimentally indistinguishable) interfering channels E{sub g} and F{sub 2g} hitherto seen solely as two-photon IR-absorption features. We make the first-ever prediction of the SF{sub 6} polarizability second derivative with respect to the ν{sub 3}-mode coordinate and we develop a heuristic argument to explain why the superposition of the three degenerate stretching motions that are related to the ν{sub 3} mode cannot but generate a polarized Raman band.

  4. The electron–phonon coupling of fundamental, overtone, and combination modes and its effects on the resonance Raman spectra

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Li, Zhanlong; Wang, Shenghan; Gao, Shuqin [College of Physics, Jilin University, Changchun 130012 (China); Sun, Chenglin, E-mail: chenglin@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Li, Zuowei [College of Physics, Jilin University, Changchun 130012 (China)

    2015-12-15

    Highlights: • The Huang–Rhys factors and electron–phonon coupling constants are calculated. • The changes of overtone mode are larger than those of fundamental mode. • The variation pattern of electron–phonon coupling well interprets the changes of spectra. - Abstract: External field plays a very important role in the interaction between the π-electron transition and atomic vibration of polyenes. It has significant effects on both the Huang–Rhys factor and the electron–phonon coupling. In this paper, the visible absorption and resonance Raman spectra of all-trans-β-carotene are measured in the 345–295 K temperature range and it is found that the changes of the 0–1 and 0–2 vibration bands of the absorption spectra with the temperature lead to the different electron–phonon coupling of fundamental, overtone, and combination modes. The electron-phonon coupling constants of all the modes are calculated and analyzed under different temperatures. The variation law of the electron–phonon coupling with the temperature well interprets the changes of the resonance Raman spectra, such as the shift, intensity and line width of the overtone and combination modes, which are all greater than those of the fundamental modes.

  5. Theoretical and experimental study of the C-H stretching overtones of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12 hexaazaisowurtzitane (CL20).

    Science.gov (United States)

    Cabalo, J; Sausa, R

    2013-09-19

    An understanding of how molecular environment and structure are reflected in optical absorption spectra offers a number of advantages, such as improved detection of materials or providing an easy means of distinguishing crystal polymorphs of the same molecular solid. This study advances this understanding by comparing near IR laser photoacoustic absorption measurements of the first C-H stretch overtones around 5975 cm(-1) of β-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL20) to simulated spectra using density functional calculations and the local mode model of C-H stretches. The calculations reveal that accounting for movement of charge throughout the model crystal unit cell with a pure quantum mechanical method in the calculation of the transition dipole moment is critical to matching the experimental data. Vibrational modes in a given molecule induce movement of charge in neighboring molecules, such that calculation of the transition dipole moment had to include the entire crystal unit cell. Movement of charge across the periodic boundary conditions (PBC) of the model needs to be accounted for to calculate a spectrum validated by the experimental measurement. The Hirshfeld population analysis minimizes discontinuities for movement of charge across the PBC.

  6. Effects of intermolecular interactions on absorption intensities of the fundamental and the first, second, and third overtones of OH stretching vibrations of methanol and t-butanol‑d9in n-hexane studied by visible/near-infrared/infrared spectroscopy.

    Science.gov (United States)

    Morisawa, Yusuke; Suga, Arisa

    2018-05-15

    Visible (Vis), near-infrared (NIR) and IR spectra in the 15,600-2500cm -1 region were measured for methanol, methanol-d 3 , and t-butanol-d 9 in n-hexane to investigate effects of intermolecular interaction on absorption intensities of the fundamental and the first, second, and third overtones of their OH stretching vibrations. The relative area intensities of OH stretching bands of free and hydrogen-bonded species were plotted versus the vibrational quantum number using logarithm plots (V=1-4) for 0.5M methanol, 0.5M methanol‑d 3 , and 0.5M t-butanol-d 9 in n-hexane. In the logarithm plots the relative intensities of free species yield a linear dependence irrespective of the solutes while those of hydrogen-bonded species deviate significantly from the linearity. The observed results suggest that the modifications in dipole moment functions of the OH bond induced by the formation of the hydrogen bondings change transient dipole moment, leading to the deviations of the dependences of relative absorption intensities on the vibrational quantum number from the linearity. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Experimental and theoretical investigation of the first overtone spectrum of 1,3,5-trinitrotoluene.

    Science.gov (United States)

    Cabalo, Jerry B; Sausa, Rosario

    2011-08-25

    Vibrational overtone spectroscopy is a powerful tool for studying intramolecular and intermolecular interactions. We report on a combined experimental and modeling study of the C-H stretch first overtone of bulk 1,3,5-trinitrotoluene (TNT) and TNT on fumed-silica powder. We recorded the overtone spectra by laser photoacoustic spectroscopy and compared them with those predicted with the harmonically coupled anharmonic oscillator model in the 5600-6600 cm(-1) region. The model systems included single molecules and hybrid quantum and molecular mechanical (QM:MM) clusters to account for the effects of intermolecular interactions on the observed spectra. We performed the hybrid QM:MM calculations at the HF/6-31+G(d,p), B3LYP/6-31+G(d,p), and MP2/6-31+G(d,p) levels of theory and with the universal force field (UFF) to account for van der Waals and electrostatic effects from surrounding molecules. Overtone spectra calculated from the MP2 level of theory, using a HF/3-21+G* calculation to assign molecular charges in the MM layer, and the Merz-Singh-Kollman population analysis for assigning partial charge in the QM layer and determining the transition dipole moment agreed best with the experimental data. © 2011 American Chemical Society

  8. Determination of the Oscillator Strengths for the Third and Fourth Vibrational Overtone Transitions in Simple Alcohols

    Science.gov (United States)

    Wallberg, Jens; Kjaergaard, Henrik G.

    2017-06-01

    Absolute measurements of the weak transitions require sensitive spectroscopic techniques. With our recently constructed pulsed cavity ring down (CRD) spectrometer, we have recorded the third and fourth vibrational overtone of the OH stretching vibration in a series of simple alcohols: methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH), 2-propanol (2-PrOH) and tert-butanol (tBuOH). The CRD setup (in a flow cell configuration) is combined with a conventional FTIR spectrometer to determine the partial pressure of the alcohols from the fundamental transitions of the OH-stretching vibration. The oscillator strengths of the overtone transitions are determined from the integrated absorbances of the overtone spectra and the partial pressures. Furthermore, the oscillator strengths were calculated using vibrational local mode theory with energies and dipole moments calculated at CCSD(T)/aug-cc-pVTZ level of theory. We find a good agreement between the observed and calculated oscillator strengths across the series of alcohols.

  9. The Cheshire-cat-like Behavior of 2nu(sub 3) Overtone of Co2 near 2.134 micron: NIR Lab Spectra of Solid CO2 in H2O and CH3OH

    Science.gov (United States)

    Bernstein, Max; Sandford, Scott; Cruikshank, Dale

    2005-01-01

    Infrared (IR) spectra have demonstrated that solid H2O is very common in the outer Solar System, and solid carbon dioxide (CO2) has been detected on icy satellites, comets, and planetismals throughout the outer Solar System. In such environments, CO2 and H2O must sometimes be mixed at a molecular level, changing their IR absorption features. In fact, the IR spectra of CO2-H2O mixtures are not equivalent to a linear combination of the spectra of the pure materials. Laboratory IR spectra of pure CO2 and H2O have been published but a lack of near-IR spectra of CO2-H2O mixtures has made the interpretation of outer Solar System spectra more difficult. We present near infrared (IR) spectra of CO2 in H2O and in CH3OH compared to that of pure solid CO2 and find significant differences. Peaks not present in either pure H2O or pure CO2 spectra become evident. First, the CO2 (2nu(sub 3)) overtone near 2.134 micron (4685/ cm) that is not seen in pure solid CO2 is prominent in the spectrum of a CO2/H2O = 25 mixture. Second, a 2.74 micron (3650/ cm) dangling OH feature of water (and a potentially related peak at 1.89 micron) appear in the spectra of CO2-H2O ice mixtures, but may not be specific to the presence of CO2. Other CO2 peaks display shifts in position and increased width because of intermolecular interactions with water. Changes in CO2 peak positions and profiles on warming of a CO2/H2O = 5 mixture are consistent with 'segregation' of the ice into nearly pure separate components. Absolute strengths for absorptions of CO2 in solid H2O are estimated. Similar results are observed for CO2 in solid CH3OH. Since the CO2 ( 2nu(sub 3)) overtone near 2.134 micron (4685/ cm) is not present in pure CO2 but prominent in mixtures it may be a good observational indicator of whether solid CO2 is a pure material or intimately mixed with other molecules. Significant changes in the near IR spectrum of solid CO2 in the presence of H2O and CH3OH means that the abundance of solid CO2 in the

  10. Scalable overtone HF chemical laser

    International Nuclear Information System (INIS)

    Jeffers, W.O.

    1988-01-01

    A method of producing essentially coherent electromagnetic emissions with high efficiency from excited HF molecules at overtone frequencies is described comprising the steps of: thermally dissociating a molecular gas containing fluorine to produce F atoms; reacting the F atoms with a gas containing hydrogen to produce excited HF molecules; preferentially depleting Δv=2 overtone vibrational transitions of the excited HF molecules to produce the electromagnetic emissions at overtone frequencies such that the electromagnetic emissions from the Δv=2 overtone vibrational transitions have an output power which is a significant percentage of the output power obtainable from Δv=1 fundamental vibrational transitions of excited HF molecules so that the electromagnetic emissions produced by the Δv=2 overtone vibrational transitions can be efficiently scaled to high output powers

  11. Polarized absorption spectra of aromatic radicals in stretched polymer film. 3. Radical ions of acridine and phenazine

    Energy Technology Data Exchange (ETDEWEB)

    Sekigucki, K.; Hiratsuka, H.; Tanizaki, Y.; Hatano, Y.

    1980-02-21

    Radical anions and cations of acridine and phenazine have been prepared in polymer film by ..gamma..-ray irradiation at 77 K. For the preparation of radical anions the sample was incorporated into polyethylene film by sec-butylamine, while for radical cations poly(vinyl chloride) film and sec-butyl chloride were used. Polarized absorption spectra of these radical ions have been measured in stretched polymer film and analyzed qualitatively in terms of molecular orbital calculations.

  12. Free radical and overtone spectroscopy

    Science.gov (United States)

    Reilly, James P.

    1991-01-01

    In the fall of 1987 during a photoacoustic study of hydrogen peroxide's fourth vibrational overtone band, the remarkably clear and well resolved spectrum was observed. Its periodicity and K subband structure suggested that the spectrum was not of hydrogen peroxide but of a smaller near-prolate symmetric top molecule. Furthermore, the time dependent behavior of the signal indicated that chemical changes were taking place within the photoacoustic apparatus.

  13. Right-side-stretched multifractal spectra indicate small-worldness in networks

    Science.gov (United States)

    Oświȩcimka, Paweł; Livi, Lorenzo; Drożdż, Stanisław

    2018-04-01

    Complex network formalism allows to explain the behavior of systems composed by interacting units. Several prototypical network models have been proposed thus far. The small-world model has been introduced to mimic two important features observed in real-world systems: i) local clustering and ii) the possibility to move across a network by means of long-range links that significantly reduce the characteristic path length. A natural question would be whether there exist several ;types; of small-world architectures, giving rise to a continuum of models with properties (partially) shared with other models belonging to different network families. Here, we take advantage of the interplay between network theory and time series analysis and propose to investigate small-world signatures in complex networks by analyzing multifractal characteristics of time series generated from such networks. In particular, we suggest that the degree of right-sided asymmetry of multifractal spectra is linked with the degree of small-worldness present in networks. This claim is supported by numerical simulations performed on several parametric models, including prototypical small-world networks, scale-free, fractal and also real-world networks describing protein molecules. Our results also indicate that right-sided asymmetry emerges with the presence of the following topological properties: low edge density, low average shortest path, and high clustering coefficient.

  14. The Overtone Fiddle: an Actuated Acoustic Instrument

    DEFF Research Database (Denmark)

    Overholt, Daniel

    2011-01-01

    The Overtone Fiddle is a new violin-family instrument that incorporates electronic sensors, integrated DSP, and physical actuation of the acoustic body. An embedded tactile sound transducer creates extra vibrations in the body of the Overtone Fiddle, allowing performer control and sensation via...

  15. Vibrational spectroscopy of triacetone triperoxide (TATP): Anharmonic fundamentals, overtones and combination bands

    Science.gov (United States)

    Brauer, Brina; Dubnikova, Faina; Zeiri, Yehuda; Kosloff, Ronnie; Gerber, R. Benny

    2008-12-01

    The vibrational spectrum of triacetone triperoxide (TATP) is studied by the correlation-corrected vibrational self-consistent field (CC-VSCF) method which incorporates anharmonic effects. Fundamental, overtone, and combination band frequencies are obtained by using a potential based on the PM3 method and yielding the same harmonic frequencies as DFT/cc-pVDZ calculations. Fundamentals and overtones are also studied with anharmonic single-mode (without coupling) DFT/cc-pVDZ calculations. Average deviations from experiment are similar for all methods: 2.1-2.5%. Groups of degenerate vibrations form regions of numerous combination bands with low intensity: the 5600-5800 cm -1 region contains ca. 70 overtones and combinations of CH stretches. Anharmonic interactions are analyzed.

  16. Polarized absorption spectra of aromatic radicals in stretched polymer film, 4. Radical ions of 9-substituted anthracenes. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hiratsuka, Hiroshi; Nakamura, Hitoshi; Tanizaki, Yoshie; Nakajima, Keihachiro (Tokyo Inst. of Tech. (Japan). Faculty of Science)

    1982-11-01

    Radical ions of some 9-substituted anthracene derivatives have been prepared in polymer film by gamma -irradiation at 77 K. By use of the polarized absorption spectra of these radical ions, the absorption spectra have been resolved into two components (resolved spectra), the transition moments of which are polarized parallel to the molecular long and short axes, respectively. Correlation of the characteristic absorption bands is discussed briefly.

  17. Infrared spectroscopy and Density Functional Theory of crystalline β-2,4,6,8,10,12-hexanitrohexaaziosowurtzitane (β CL-20) in the region of its C-H stretching vibrations.

    Science.gov (United States)

    Behler, K D; Pesce-Rodriguez, R; Cabalo, J; Sausa, R

    2013-10-01

    Molecular vibrational spectroscopy provides a useful tool for material characterization and model verification. We examine the CH stretching fundamental and overtones of energetic material β-2,4,6,8,10,12-hexanitrohexaaziosowurtzitane (β-CL-20) by Raman spectroscopy, Fourier Transform Infrared Spectroscopy, and Laser Photoacoustic Overtone Spectroscopy, and utilize Density Functional Theory to calculate the C-H bond energy of β-CL-20 in a crystal. The spectra reveal four intense and distinct features, whose analysis yields C-H stretching fundamental frequencies and anharmonicity values that range from 3137 to 3170 cm(-1) and 53.8 to 58.8 cm(-1), respectively. From these data, we estimate an average value of 42,700 cm(-1) (5.29 eV) for the C-H bond energy, a value that agrees with our quantum mechanical calculations. Published by Elsevier B.V.

  18. Near IR overtone spectral investigations of cyclohexanol using local mode model--evidence for variation of anharmonicity with concentration due to hydrogen bonding.

    Science.gov (United States)

    John, Usha; Nair, K P R

    2005-09-01

    The near infrared vibrational overtone absorption spectrum of liquid phase cyclohexanol in carbon tetrachloride in different concentrations are examined in the region Deltav=2, 3 and 4. The free and bonded OH local mode mechanical frequency values and anharmonicity values obtained from fitting the overtones are analysed. The observation supports the conclusions drawn from earlier experimental studies on anharmonicity variation of OH-stretching vibrations of alcohols due to intermolecular hydrogen bonding. Our observation is also in agreement with the ab initio calculations on water dimer and trimer. Mechanical anharmonicity of bonded OH-stretching bands tends to increase as a consequence of strong hydrogen bonding at higher concentrations.

  19. Correlated High-Frequency Molecular Motions in Neat Liquid Probed with Ultrafast Overtone Two-Dimensional Infrared Spectroscopy.

    Science.gov (United States)

    Li, Donghai; Yang, Fan; Han, Chen; Zhao, Juan; Wang, Jianping

    2012-12-06

    In this work, an overtone two-dimensional infrared (2D IR) method is shown to allow correlated molecular motions at the frequencies of overtone transitions to be studied. Waiting-time-dependent overtone 2D IR results of the C-O stretching in neat liquid methanol reveal that the autocorrelation of the v = 0 → 2 transition and the cross correlation of the v = 0 → 2/v = 2 → 4 transitions differ considerably (relaxation time being 700 fs and 2 ps, respectively), suggesting different spectral diffusion dynamics. Quantum-chemical computations in combination with ab initio molecular dynamics simulations show that the overtone transition frequency of the C-O stretching mode in liquid methanol is of more structural sensitivity than the fundamental frequency. This work demonstrates a new 2D IR approach to examining the structural sensitivities of the anharmonic potential parameters of higher vibrational states, which can be used to gain new insight into the ultrafast structural dynamics particularly for neat liquids.

  20. New investigation of the ν3 C-H stretching region of 12CH4 through the analysis of high temperature infrared emission spectra.

    Science.gov (United States)

    Amyay, Badr; Gardez, Aline; Georges, Robert; Biennier, Ludovic; Vander Auwera, Jean; Richard, Cyril; Boudon, Vincent

    2018-04-07

    The ν 3 C-H stretching region of methane was reinvestigated in this work using high temperature (620-1715 K) emission spectra recorded in Rennes at Doppler limited resolution. This work follows our recent global analysis of the Dyad system Δn = ±1 (1000-1500 cm -1 ), with n being the polyad number [B. Amyay et al., J. Chem. Phys. 144, 24312 (2016)]. Thanks to the high temperature, new assignments of vibration-rotation methane line positions have been achieved successfully in the Pentad system and some associated hot bands (Δn = ±2) observed in the spectral region 2600-3300 cm -1 . In particular, rotational assignments in the cold band [Pentad-ground state (GS)] and in the first related hot band (Octad-Dyad) were extended up to J = 30 and 27, respectively. In addition, 1525 new transitions belonging to the Tetradecad-Pentad hot band system were assigned for the first time, up to J = 20. The effective global model used to deal with the new assignments was developed to the 6th order for the first three polyads (Monad, Dyad, and Pentad), and to the 5th order for both the Octad and the Tetradecad. 1306 effective parameters were fitted with a dimensionless standard deviation σ = 2.64. The root mean square deviations d RMS obtained are 4.18 × 10 -3 cm -1 for the Pentad-GS cold band, 2.48 × 10 -3 cm -1 for the Octad-Dyad, and 1.43 × 10 -3 cm -1 for the Tetradecad-Pentad hot bands.

  1. Overtone spectroscopy of some benzaldehyde derivatives

    Indian Academy of Sciences (India)

    chlorobenzaldehyde has been studied in 2000–12000 cm-1 region. Vibrational frequencies and anharmonicity constants for aryl as well as alkyl CH stretch vibrations have been determined. We have also determined the internuclear distances for the aryl CH ...

  2. Overtone spectroscopy of some benzaldehyde derivatives

    Indian Academy of Sciences (India)

    chlorobenzaldehyde have been undertaken with the following objectives: 1. To see if the Fermi resonance seen in the alkyl CH stretch region for benzaldehyde, ortho hydroxy and methoxy benzaldehydes is present in the present group of com- pounds.

  3. Quantitative infrared and near-infrared gas-phase spectra for pyridine: Absolute intensities and vibrational assignments

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, T. J.; Aker, P. M.; Scharko, N. K.; Williams, S. D.

    2018-02-01

    Using vetted methods for generating quantitative absorption reference data, broadband infrared and near-infrared spectra (total range 11,000 – 600 cm-1) of pyridine vapor were recorded at 0.1 cm-1 spectral resolution, with the analyte thermostatted at 298 K and pressure-broadened to 1 atmosphere using N2 ballast gas. The quantitative spectrum is reported for the first time, and we have re-assigned some of the 27 fundamental modes. Fundamental assignments were confirmed by IR vapor phase band shapes, FT-Raman measurements and comparison with previous analyses. For the 760-Torr vapor-phase IR data several bands show resolved peaks (Q-branches). We have also assigned for the first time hundreds of combination and overtone bands in the mid- and near-IR. All assignments were made via comparison to theoretically calculated frequencies and intensities: The frequencies were computed with Gaussian03 with the anharmonic option, using MP2 and the ccpvtz basis set. The intensities were taken from a VSCF calculation in GAMESS using Hartree-Fock (for overtones and combination bands) or from the harmonic MP2 for fundamentals. Overtone and combination band harmonic and anharmonic frequencies, as well as intensities were also calculated using the CFOUR program. It is seen in the NIR spectrum near 6000 cm-1 that the very strong bands arise from the C-H first overtones, whereas only much weaker bands are observed for combination bands of C-H stretching modes. Certain features are discussed for their potential utility for atmospheric monitoring.

  4. Infrared and Raman Spectra of and Isotopomers: A DFT-PT2 Anharmonic Study

    Directory of Open Access Journals (Sweden)

    Andrea Alparone

    2013-01-01

    Full Text Available IR and Raman spectra of selenophene and of its perdeuterated isotopomer have been obtained in gas phase through density-functional theory (DFT computations. Vibrational wavenumbers have been calculated using harmonic and anharmonic second-order perturbation theory (PT2 procedures with the B3LYP method and the 6-311 basis set. Anharmonic overtones have been determined by means of the PT2 method. The introduction of anharmonic terms decreases the harmonic wavenumbers, giving a significantly better agreement with the experimental data. The most significant anharmonic effects occur for the C–H and C–D stretching modes, the observed H/D isotopic wavenumber redshifts being satisfactorily reproduced by the PT2 computations within 6–20 cm−1 (1–3%. In the spectral region between 500 cm−1 and 1500 cm−1, the IR spectra are dominated by the out-of-plane C–H (C–D bending transition, whereas the Raman spectra are mainly characterized by a strong peak mainly attributed to the C=C + C–C bonds stretching vibration with the contribution of the in-plane C–H (C–D bending deformation. The current results confirm that the PT2 approach combined with the B3LYP/6-311 level of calculation is a satisfactory choice for predicting vibrational spectra of cyclic molecules.

  5. Strong overtones and combination bands in ultraviolet resonance Raman spectroscopy

    NARCIS (Netherlands)

    Efremov, E.V.; Ariese, F.; Mank, A.J.G.; Gooijer, C.

    2006-01-01

    Ultraviolet resonance Raman spectroscopy is carried out using a continuous wave frequency-doubled argon ion laser operated at 229, 244, and 257 nm in order to characterize the overtones and combination bands for several classes of organic compounds in liquid solutions. Contrary to what is generally

  6. Strong overtones modes in inelastic electron tunneling spectroscopy with cross-conjugated molecules

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2013-01-01

    that overtones are not observable in IETS. Here, overtones are predicted to be strong and, in some cases, the dominant spectroscopic features. We study the origin of the overtones and find that the interference features in these molecules are the key ingredient. The interference feature is a property...

  7. High overtones of Schwarzschild-de-Sitter quasinormal spectrum

    International Nuclear Information System (INIS)

    Konoplya, R.A.; Zhidenko, A.

    2004-01-01

    We find the high overtones of gravitational and electromagnetic quasinormal spectrum of the Schwarzschild-de Sitter black hole. The calculations show that the real parts of the electromagnetic modes asymptotically approach zero. The gravitational modes show more peculiar behavior at large n: the real part oscillates as a function of imaginary even for very high overtones and these oscillations settles to some 'profile' which just repeats itself with further increasing of the overtone number n. This lets us judge that Reω is not a constant as n →∞ but rather some oscillating function. The spacing for imaginary part Imω n+1 -Imω n for electromagnetic perturbations at high n slowly approach k e as n→∞, where k e is the surface gravity. In addition we find the lower QN modes for which the values obtained with numerical methods are in a very good agreement with those obtained through the 6th order WKB technique. (author)

  8. Developing a Stretching Program.

    Science.gov (United States)

    Beaulieu, J E

    1981-11-01

    In brief: Although stretching exercises can prevent muscle injuries and enhance athletic performance, they can also cause injury. The author explains the four most common types of stretching exercises and explains why he considers static stretching the safest. He also sets up a stretching routine for runners. In setting up a safe stretching program, one should (1) precede stretching exercises with a mild warm-up; (2) use static stretching; (3) stretch before and after a workout; (4) begin with mild and proceed to moderate exercises; (5) alternate exercises for muscle groups; (6) stretch gently and slowly until tightness, not pain, is felt; and (7) hold the position for 30 to 60 seconds.

  9. Stretch Sensor Device

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases...

  10. Observation of the v′=8←v=0 vibrational overtone in cold trapped HD +

    NARCIS (Netherlands)

    J.C.J. Koelemeij; D.W.E. Noom; D. de Jong; M.A. Haddad; W. Ubachs

    2011-01-01

    textabstractWe report the observation of the hitherto undetected v′=8←v=0 vibrational overtone in trapped HD+molecular ions, sympathetically cooled by laser-cooled Be+ions. The overtone is excited using 782 nm laser radiation, after which HD+ions in v=8 are photodissociated by the 313 nm laser used

  11. Rotationally resolved overtone spectroscopy of the NO Ar complex

    Science.gov (United States)

    Kim, Y.; Patton, K.; Fleniken, J.; Meyer, H.

    2000-03-01

    The infrared absorption spectrum of the NO-Ar complex is measured in the region of the first NO overtone band using a new type of IR-UV double resonance technique which combines IR excitation with (2+1) resonance enhanced multiphoton ionization detection. The long lifetime of the complex (⩾30 ns) allows the sensitive detection of the vibrationally excited complex itself. Two bands corresponding to ΔP=0 and ΔP=+1 transitions are observed at 3723.4 and 3727.4 cm -1. The rotational analysis is based on a rigid rotor model Hamiltonian and yields the rotational constants A'=1.795(5) cm -1, B'=0.0785(2) cm -1, and C'=0.0615(1) cm -1. The observed splitting of rotational lines is consistent with an increased quenching constant ζ'=4.0(5) cm -1.

  12. Two Great Transfers of Word Emotive Overtones In Modern Chinese

    Directory of Open Access Journals (Sweden)

    Diao Yanbin

    2008-10-01

    Full Text Available Since 1949, modern Chinese language has, in the course of its development in Mainland China, twice witnessed large-scale transfers in its word emotive overtones. The first began in 1949 and went on all the way till the end of the Cultural Revolution in 1977. Derogation manifested itself in that period, during which the derogatory words enjoyed their greatest number, widest usages and highest frequency in the history of the Chinese language. The second began from the Reform and Opening Up Policy in 1978 and lasted untill now. De-derogation has manifested itself in this period, during which the derogatory words have had the smallest number, least usages and lowest frequency in the history of the Chinese language. The two large-scale transfers result from their specific social backgrounds and the development of the Chinese language itself.

  13. Constructions of self: ethical overtones in surprising locations.

    Science.gov (United States)

    Kinsella, E A

    2005-12-01

    Little discussion has occurred in the health profession literature with respect to how the "self" is constructed, despite the imagination and attention it has garnered from philosophers and theorists in various other disciplines. Yet this subject has surprisingly ethical overtones for health professional education and practice. In this paper notions of the self are briefly considered and it is suggested that a narrative and dialogic view of self can contribute to insights about ethical practice in the health professions. Subtle issues with respect to how relationship and language may be used to wield power are revealed and discussed; and awareness about how such power is used in practice is highlighted as a crucial issue. The assumptions practitioners make with respect to constructions of self are ethically important and this topic warrants consideration in the medical humanities.

  14. Espectro Vibracional no Infravermelho Próximo dos Polímeros Poliestireno, Poli(Metacrilato de Metila e Policarbonato Near-Infrared Spectra of Polystyrene, Poly(Methyl Methacrylate and Polycarbonate

    Directory of Open Access Journals (Sweden)

    Sérgio C. de Araújo

    2001-01-01

    Full Text Available Os espectros no infravermelho próximo (NIR dos polímeros amorfos poliestireno (PS, poli(metacrilato de metila (PMMA e policarbonato (PC foram estudados. A tentativa de atribuição das bandas harmônicas e de combinação dos modos vibracionais do PS, PMMA e PC foi realizada baseando-se na teoria de modos locais e pelo uso do método matemático de ajuste de curvas. A correção de anarmonicidade e freqüência mecânica foi determinada em um gráfico de Birge-Sponer. Uma correção de anarmonicidade de 57 e 58 cm-1 foi obtida para os modos de estiramento dos grupos CH2 e CH do PS; 59 e 9 cm-1 para os modos de estiramento dos grupos CH3 e CO do PMMA e 53, 59 e 10 cm-1 para os modos de estiramento dos grupos CH, CH3 e CO do PC, respectivamente.The near-infrared (NIR spectra of the amorphous polymers polystyrene (PS, poly(methyl methacrylate (PMMA, and polycarbonate (PC have been studied. The tentative assignment of the overtone and combination frequencies is made using the curve fitting calculations and the local mode theory. Anharmonicity correction and mechanical frequency were determined from a Birge-Sponer plot. A tentative assignment of stretch overtone frequency of CH2 and CH functional groups of PS; CH3 and CO functional groups of PMMA and CH, CH3 and CO functional groups of PC has been made. An anharmonicity correction of 57 and 58 cm-1 was obtained for CH2 and CH stretch modes of PS; 59 and 9 cm-1 for CH3 and CO stretch modes of PMMA and 53, 59 and 10 cm-1 for CH, CH3 and CO stretch modes of PC, respectively.

  15. Blinded by the light: on the relationship between CO first overtone emission and mass accretion rate in massive young stellar objects

    Science.gov (United States)

    Ilee, J. D.; Oudmaijer, R. D.; Wheelwright, H. E.; Pomohaci, R.

    2018-04-01

    To date, there is no explanation as to why disc-tracing CO first overtone (or `bandhead') emission is not a ubiquitous feature in low- to medium-resolution spectra of massive young stellar objects, but instead is only detected toward approximately 25 per cent of their spectra. In this paper, we investigate the hypothesis that only certain mass accretion rates result in detectable bandhead emission in the near infrared spectra of MYSOs. Using an analytic disc model combined with an LTE model of the CO emission, we find that high accretion rates (≳ 10-4 M⊙yr-1) result in large dust sublimation radii, a larger contribution to the K-band continuum from hot dust at the dust sublimation radius, and therefore correspondingly lower CO emission with respect to the continuum. On the other hand, low accretion rates (≲ 10-6 M⊙yr-1) result in smaller dust sublimation radii, a correspondingly smaller emitting area of CO, and thus also lower CO emission with respect to the continuum. In general, moderate accretion rates produce the most prominent, and therefore detectable, CO first overtone emission. We compare our findings to a recent near-infrared spectroscopic survey of MYSOs, finding results consistent with our hypothesis. We conclude that the detection rate of CO bandhead emission in the spectra of MYSOs could be the result of MYSOs exhibiting a range of mass accretion rates, perhaps due to the variable accretion suggested by recent multi-epoch observations of these objects.

  16. Stretching Safely and Effectively

    Science.gov (United States)

    ... of stretching before or after hitting the trail, ballet floor or soccer field. Before you plunge into ... ballistic stretching on strength and muscular fatigue of ballet dancers and resistance-trained women. Journal of Strength ...

  17. Experimental and Theoretical Study of First Overtone Carbon Monoxide Laser Physics

    National Research Council Canada - National Science Library

    Ionin, Andre

    1997-01-01

    ...: The contractor will investigate the variation of specific input energy, gas density, gas temperature, pump pulse duration, and mixture on the operation of a CO laser operating on the first overtone...

  18. Dissociative ionization of liquid water induced by vibrational overtone excitation

    International Nuclear Information System (INIS)

    Natzle, W.C.

    1983-03-01

    Photochemistry of vibrationally activated ground electronic state liquid water to produce H + and OH - ions has been initiated by pulsed, single-photon excitation of overtone and combination transitions. Transient conductivity measurements were used to determine quantum yields as a function of photon energy, isotopic composition, and temperature. The equilibrium relaxation rate following perturbation by the vibrationally activated reaction was also measured as a function of temperature reaction and isotopic composition. In H 2 O, the quantum yield at 283 +- 1 K varies from 2 x 10 -9 to 4 x 10 -5 for wave numbers between 7605 and 18140 cm -1 . In D 2 O, the dependence of quantum yield on wavelength has the same qualitative shape as for H 2 O, but is shifted to lower quantum yields. The position of a minimum in the quantum yield versus hydrogen mole fraction curve is consistent with a lower quantum yield for excitation of HOD in D 2 O than for excitation of D 2 O. The ionic recombination distance of 5.8 +- 0.5 A is constant within experimental error with temperature in H 2 O and with isotopic composition at 25 +- 1 0 C

  19. Spectroscopic and Quantum Mechanical Calculation Study of the Effect of Isotopic Substitution on NIR Spectra of Methanol.

    Science.gov (United States)

    Grabska, Justyna; Czarnecki, Mirosław A; Beć, Krzysztof B; Ozaki, Yukihiro

    2017-10-19

    In this work, we studied methanol and its deuterated derivatives (CH 3 OH, CH 3 OD, CD 3 OH, CD 3 OD) by NIR spectroscopy and anharmonic quantum chemical calculations. Vibrational bands corresponding to up to three quanta transitions (first and second overtones, binary and ternary combination modes) were predicted by the use of the VPT2 route. The accuracy of prediction of NIR modes was evaluated through density functional theory (DFT) with selected density functionals and basis sets. On the basis of the theoretical NIR spectra, detailed band assignments for all studied molecules were proposed. It was found that the pattern of bands in NIR spectra of deuterated methanols can be used for identification of isotopically equalized forms. Calculations of NIR spectra of all possible forms of CXXXOX (X = H, D) molecules demonstrated that the isotopic contamination can be identified due to a coexistence of bands specific to OH and OD groups. Also, bands from partially deuterated methyl groups can be distinguished in NIR spectra. Since the VPT2 framework is known to be sensitive to inaccuracy in the case of highly anharmonic modes, we obtained an independent insight by numerical solving of the time-independent Schrödinger equation corresponding to the O-X stretching mode scanned within -0.4 to 2.0 Å over a dense grid of 0.005 Å. This way the energies of vibrational levels of the CX1X2X3OX4 (X = H, D) isotopomers and the corresponding transition frequencies were obtained with high accuracy (<0.1 cm -1 ). The change in normal coordinate influences the reduced mass of the oscillator and thus its frequency. Our results lead to a conclusion that the effect of deuterization of the methyl group introduces a very specific and consistent frequency shift of the first overtone of the O-X stretching mode depending on the substitution of X1, X2, or X3 positions (<2 cm -1 ). However, the pattern of this shift is not reproduced accurately and is also largely overestimated by VPT2

  20. Even-odd alternation of near-infrared spectra of alkane-α,ω-diols in their solid states.

    Science.gov (United States)

    Toyama, Yuta; Murakami, Kohei; Yoshimura, Norio; Takayanagi, Masao

    2018-05-15

    Even-odd alternation of the melting points of α,ω-disubstituted linear alkanes such as alkane-α,ω-diols, alkane-α,ω-dinitriles and α,ω-diaminoalkanes is well known. Melting points for compounds with an even number of carbons in their alkyl chains are systematically higher than those for compounds with an odd number of carbons. In order to clarify the origin of this alternation, near-infrared absorption spectra of linear alkane-α,ω-diols with 3 to 9 carbon atoms in their alkyl chains were measured in the liquid and solid states. The band due to the first overtone of the OH stretching mode was investigated. The temperature-dependent spectra of all alkane-α,ω-diols in their liquid states were found to be similar; no even-odd alternation was observed. In the solid state, however, spectra of alkane-α,ω-diols with even and odd numbers of carbon atoms differed greatly. Spectra of alkane-α,ω-diols with an odd number of carbon atoms in their solid states were similar to those in the liquid states, although the variation of spectra observed upon lowering the temperature of liquid seemed to continue when the liquids were frozen. In contrast, spectra of alkane-α,ω-diols with an even number of carbon atoms in their liquid and solid states were found to be quite different. New bands appeared upon freezing. The observed even-odd alternation of the spectra observed for alkane-α,ω-diols in their solid states is presumably caused by their even-odd alternation of crystal structures. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Stretched Wire Mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Bowden, Gordon; /SLAC

    2005-09-06

    Stretched wires are beginning to play an important role in the alignment of accelerators and synchrotron light sources. Stretched wires are proposed for the alignment of the 130 meter long LCLS undulator. Wire position technology has reached sub-micron resolution yet analyses of perturbations to wire straightness are hard to find. This paper considers possible deviations of stretched wire from the simple 2-dimensional catenary form.

  2. Frequency Tuning of IR First-Overtone CO Laser Radiation by Diffraction Grating and Frequency Selective Output Couplers

    National Research Council Canada - National Science Library

    Ionin, Andre

    1999-01-01

    ...: The contractor will investigate, both experimentally and theoretically, the feasibility of frequency tuning the first overtone carbon monoxide laser radiation by the use of diffraction gratings...

  3. OH-stretch overtone of methanol: empirical assignment using a two temperature technique in a supersonic jet

    Czech Academy of Sciences Publication Activity Database

    Svoboda, V.; Horká-Zelenková, Veronika; Rakovský, Jozef; Pracna, Petr; Votava, Ondřej

    2015-01-01

    Roč. 17, č. 24 (2015), s. 15710-15717 ISSN 1463-9076 R&D Projects: GA ČR GA13-11635S Institutional support: RVO:61388955 Keywords : VIBRATIONALLY EXCITED METHANOL * INTRAMOLECULAR ENERGY-TRANSFER * MU-M Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.449, year: 2015

  4. Stretching: Does It Help?

    Science.gov (United States)

    Vardiman, Phillip; Carrand, David; Gallagher, Philip M.

    2010-01-01

    Stretching prior to activity is universally accepted as an important way to improve performance and help prevent injury. Likewise, limited flexibility has been shown to decrease functional ability and predispose a person to injuries. Although this is commonly accepted, appropriate stretching for children and adolescents involved with sports and…

  5. Dynamic stretching is effective as static stretching at increasing flexibility

    OpenAIRE

    Coons, John M.; Gould, Colleen E.; Kim, Jwa K.; Farley, Richard S.; Caputo, Jennifer L.

    2017-01-01

    This study examined the effect of dynamic and static (standard) stretching on hamstring flexibility. Twenty-five female volleyball players were randomly assigned to dynamic (n = 12) and standard (n = 13) stretching groups. The experimental group trained with repetitive dynamic stretching exercises, while the standard modality group trained with static stretching exercises. The stretching interventions were equivalent in the time at stretch and were performed three days a week for four weeks. ...

  6. Biocatalysis: Unmasked by stretching

    Science.gov (United States)

    Kharlampieva, Eugenia; Tsukruk, Vladimir V.

    2009-09-01

    The biocatalytic activity of enzyme-loaded responsive layer-by-layer films can be switched on and off by simple mechanical stretching. Soft materials could thus be used to trigger biochemical reactions under mechanical action, with potential therapeutic applications.

  7. Frictional effects between Overton sand and a simulated casing for a bore hole

    International Nuclear Information System (INIS)

    Dong, R.G.

    1975-01-01

    A series of tests were run to simulate the frictional effects between Overton sand and the casing for a bore hole for an underground nuclear test. The objective was to find a description for this frictional interaction which can be applied to an analysis of stemming materials under field conditions

  8. Overtones of isoscalar giant resonances studied in direct particle decay measurements

    NARCIS (Netherlands)

    Hunyadi, M; van den Berg, AM; Csatlos, M; Csige, L; Davids, B; Garg, U; Gulyas, J; Harakeh, MN; de Huu, MA; Krasznahorkay, A; Sohler, D; Wortche, HJ

    The isoscalar giant dipole resonance (ISGDR), which is the lowest-energy overtone mode of the isoscalar giant resonances, has been studied in some medium-heavy and heavy nuclei in coincidence measurements. The observation of the direct nucleon decay channels significantly helped to enhance giant

  9. The MACHO Project SMC Variable Star Inventory: I. The Second-overtone Mode of Cepheid Pulsation From First/Second Overtone (1H/2H) Beat Cepheids

    OpenAIRE

    The MACHO Collaboration; Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Freeman, K. C.; Griest, K.; Lehner, M. J.; Marshall, S. L.; Peterson, B. A.; Quinn, P. J.; Rodgers, A. W.

    1997-01-01

    We report the discovery of 20 1H/2H and 7 F/1H beat Cepheids in the SMC by the MACHO Project. We utilize the 20 1H/2H stars to determine lightcurve shape for the SMC second-overtone (2H) mode of Cepheid pulsation. We predict, similar to the findings of Alcock et al. (1997, ApJ, submitted), that 2H Cepheids will have nearly or purely sinusoidal light variations; that the P-L relation for 2H Cepheids will not be distinguishable from the P-L relation for 1H Cepheids within photometric accuracy; ...

  10. Spectra-structure correlations in NIR region: Spectroscopic and anharmonic DFT study of n-hexanol, cyclohexanol and phenol.

    Science.gov (United States)

    Beć, Krzysztof B; Grabska, Justyna; Czarnecki, Mirosław A

    2018-05-15

    We investigated near-infrared (7500-4000 cm -1 ) spectra of n-hexanol, cyclohexanol and phenol in CCl 4 (0.2 M) by using anharmonic quantum calculations. These molecules represent three major kinds of alcohols; linear and cyclic aliphatic, and aromatic ones. Vibrational second-order perturbation theory (VPT2) was employed to calculate the first overtones and binary combination modes and to reproduce the experimental NIR spectra. The level of conformational flexibility of these three alcohols varies from one stable conformer of phenol through four conformers of cyclohexanol to few hundreds conformers in the case of n-hexanol. To take into account the most relevant conformational population of n-hexanol, a systematic conformational search was performed. Accurate reproduction of the experimental NIR spectra was achieved and detailed spectra-structure correlations were obtained for these three alcohols. VPT2 approach provides less reliable description of highly anharmonic modes, i.e. OH stretching. In the present work this limitation was manifested in erroneous results yielded by VPT2 for 2νOH mode of cyclohexanol. To study the anharmonicity of this mode we solved the corresponding time-independent Schrödinger equation based on a dense-grid probing of the relevant vibrational potential. These results allowed for significant improvement of the agreement between the calculated and experimental 2νOH band of cyclohexanol. Various important biomolecules include similar structural units to the systems investigated here. A detailed knowledge on spectral properties of these three types of alcohols is therefore essential for advancing our understanding of NIR spectroscopy of biomolecules. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Concentrations of anesthetics across the water-membrane interface; the Meyer-Overton hypothesis revisited

    Science.gov (United States)

    Pohorille, A.; Wilson, M. A.; New, M. H.; Chipot, C.

    1998-01-01

    The free energies of transferring a variety of anesthetic and nonanesthetic compounds across water-oil and water-membrane interfaces were obtained using computer simulations. Anesthetics exhibit greatly enhanced concentrations at these interfaces, compared to nonanesthetics. The substitution of the interfacial solubilites of the anesthetics for their bulk lipid solubilities in the Meyer-Overton relation, was found to give a better correlation, indicating that the potency of an anesthetic is directly proportional to its solubility at the interface.

  12. Torsion-rotation structure and quasi-symmetric-rotor behaviour for the CH3SH asymmetric CH3-bending and C-H stretching bands of E parentage

    Science.gov (United States)

    Lees, R. M.; Xu, Li-Hong; Guislain, B. G.; Reid, E. M.; Twagirayezu, S.; Perry, D. S.; Dawadi, M. B.; Thapaliya, B. P.; Billinghurst, B. E.

    2018-01-01

    High-resolution Fourier transform spectra of the asymmetric methyl-bending and methyl-stretching bands of CH3SH have been recorded employing synchrotron radiation at the FIR beamline of the Canadian Light Source. Analysis of the torsion-rotation structure and relative intensities has revealed the novel feature that for both bend and stretch the in-plane and out-of-plane modes behave much like a Coriolis-coupled l-doublet pair originating from degenerate E modes of a symmetric top. As the axial angular momentum K increases, the energies of the coupled "l = ±1" modes diverge linearly, with effective Coriolis ζ constants typical for symmetric tops. For the methyl-stretching states, separated at K = 0 by only about 1 cm-1, the assigned sub-bands follow a symmetric top Δ(K - l) = 0 selection rule, with only ΔK = -1 transitions observed to the upper l = -1 in-plane A‧ component and only ΔK = +1 transitions to the lower l = +1 out-of-plane A″ component. The K = 0 separation of the CH3-bending states is larger at 9.1 cm-1 with the l-ordering reversed. Here, both ΔK = +1 and ΔK = -1 transitions are seen for each l-component but with a large difference in relative intensity. Term values for the excited state levels have been fitted to J(J + 1) power-series expansions to obtain substate origins. These have then been fitted to a Fourier model to characterize the torsion-K-rotation energy patterns. For both pairs of vibrational states, the torsional energies display the customary oscillatory behaviour as a function of K and have inverted torsional splittings relative to the ground state. The spectra show numerous perturbations, indicating local resonances with the underlying bath of high torsional levels and vibrational combination and overtone states. The overall structure of the two pairs of bands represents a new regime in which the vibrational energy separations, torsional splittings and shifts due to molecular asymmetry are all of the same order, creating a

  13. Stretching & Flexibility: An Interactive Encyclopedia of Stretching. [CD-ROM].

    Science.gov (United States)

    2002

    This CD-ROM offers 140 different stretches in full-motion video sequences. It focuses on the proper techniques for overall physical fitness, injury prevention and rehabilitation, and 23 different sports (e.g., golf, running, soccer, skiing, climbing, football, and baseball). Topics include stretching for sports; stretching awareness and education…

  14. Stretching the Border

    DEFF Research Database (Denmark)

    Horstmann, Alexander

    2014-01-01

    In this paper, I hope to add a complementary perspective to James Scott’s recent work on avoidance strategies of subaltern mountain people by focusing on what I call the refugee public. The educated Karen elite uses the space of exile in the Thai borderland to reconstitute resources and to re-ent......-based organizations succeed to stretch the border by establishing a firm presence that is supported by the international humanitarian economy in the refugee camps in Northwestern Thailand....

  15. Dynamics of the OH stretching mode in crystalline Ba(ClO4)2.3H2O

    Science.gov (United States)

    Hutzler, Daniel; Brunner, Christian; Petkov, Petko St.; Heine, Thomas; Fischer, Sighart F.; Riedle, Eberhard; Kienberger, Reinhard; Iglev, Hristo

    2018-02-01

    The vibrational dynamics of the OH stretching mode in Ba(ClO4)2 trihydrate are investigated by means of femtosecond infrared spectroscopy. The sample offers plane cyclic water trimers in the solid phase that feature virtually no hydrogen bond interaction between the water molecules. Selective excitation of the symmetric and asymmetric stretching leads to fast population redistribution, while simultaneous excitation yields quantum beats, which are monitored via a combination tone that dominates the overtone spectrum. The combination of steady-state and time-resolved spectroscopy with quantum chemical simulations and general theoretical considerations gives indication of various aspects of symmetry breakage. The system shows a joint population lifetime of 8 ps and a long-lived coherence between symmetric and asymmetric stretching, which decays with a time constant of 0.6 ps.

  16. Kontrola kvalitete stretch folije

    OpenAIRE

    Gržanić, Nino

    2016-01-01

    U završnom radu opisan je postupak ekstrudiranja i kontrole kvalitete stretch folije koji se koristi u firmi Bomark-Pak radi osiguravanja najbolje kvalitete. Kontrola kreče kod uvoza repromaterijala, nastavlja se kod izrade folije na stroju, te se glavni dio odvija nakon izrade gotovg proizvoda. U radu ćemo detaljno objasniti svaki pojedini korak, zašto se on vrši, te uz pomoć kojih mjernih instrumenata se izvršava.

  17. Cepheids in Magellanic Cloud star clusters - Fundamental and overtone pulsators in NGC 2157

    Science.gov (United States)

    Mateo, Mario; Olszewski, Edward W.; Madore, Barry F.

    1990-01-01

    CCD survey data are employed to examine Cepheids in young Magellanic Cloud star clusters. The properties of three Cepheids observed in NGC 2157 are described. It is detected that the two short-period (3 days) Cepheids have photometric properties that correspond to overtone pulsators and the long-period (7.7 days) Cepheid pulses in the fundamental mode. The pulsational masses for the three Cepheids are calculated to be about 5 solar masses. This mass value does not correlate with the average pulsational mass for Cepheids of 3.0 + or - 0.4 solar masses. The potential cause of this deviation in evolutionary/pulsational mass is investigated.

  18. The pattern of eigenfrequencies of radial overtones which is predicted for a specified Earth-model

    Directory of Open Access Journals (Sweden)

    E. R. LAPWOOD

    1977-06-01

    Full Text Available In 1974 Anderssen and Cleary examined the distribution of eigenfrequencies
    of radial overtones in torsional oscillations of Earth-models.
    They pointed out that according to Sturm-Liouville theory this distribution
    should approach asymptotically, for large overtone number m,
    the value nnz/y, where y is the time taken by a shear-wave to travel
    along a radius from the core-mantle interface to the surface, provided
    elastic parameters vary continuously along the radius. They found that,
    for all the models which they considered, the distributions of eigenfrequencies
    deviated from the asymptote by amounts which depended on
    the existence and size of internal discontinuities. Lapwood (1975 showed
    that such deviations were to be expected from Sturm-Liouville theory,
    and McNabb, Anderssen and Lapwood (1976 extended Sturm-Liouville
    theory to apply to differential equations with discontinuous coefficients.
    Anderssen (1977 used their results to show how to predict the pattern
    of deviations —called by McNabb et al. the solotone effect— for a
    given discontinuity in an Earth-model.
    Recently Sato and Lapwood (1977, in a series of papers which will
    be referred to here simply as I, II, III, have explored the solotone effect
    for layered spherical shells, using approximations derived from an exacttheory which holds for uniform layering. They have shown how the
    form of the pattern of eigenfrequencies, which is the graph of
    S — YMUJI/N — m against m, where ,„CJI is the frequency of the m"'
    overtone in the I"' (Legendre mode of torsional oscillation, is determined
    as to periodicity (or quasi-periodicity by the thicknesses and velocities
    of the layers, and as to amplitude by the amounts of the discontinuities
    (III. The pattern of eigenfrequencies proves to be extremely sensitive
    to small changes in layer-thicknesses in a model.
    In

  19. Femtosecond wavevector overtone spectroscopy of anharmonic lattice dynamics in ferroelectric crystals

    Science.gov (United States)

    Brennan, Ciaran Joseph

    Impulse Stimulated Raman Scattering (ISRS) is a useful technique for characterizing the soft optic modes that are responsible for the polar distortion in ferroelectric crystals. ISRS provides an impulse force to the selected mode at a specific wavevector, and the subsequent oscillations and damping of the mode can be observed. Previous researchers have used this technique to measure the wavevector-dependent frequency and damping of optic phonons and phonon-polaritons in a variety of ferroelectric crystals. The recent development of powerful amplified Ti:sapphire femtosecond lasers opens the possibility that the impulse force applied to the ferroelectric soft mode is so large that the resultant ionic excursions will sample the anharmonic portions of the potential energy surface for the soft mode. This would, in principle, allow the experimental measurement of the potential energy surface by carefully characterizing the anharmonic content of the ISRS signals. This information would give insight into the causal mechanism for the phenomenon of ferroelectricity. Measurements of anharmonic phonon-polaritons in ferroelectric crystals have been performed using Wavevector Overtone Spectroscopy (WOS), a refinement of the impulsive stimulated Raman scattering (ISRS) technique. Numerical simulations suggest that harmonics of the polariton wavevector, rather than harmonics of the polariton frequency, are the key signatures of lattice anharmonicity in a time resolved grating experiment. The predicted signals at the wavevector overtones were observed up to the 5th order in LiTaO3, providing strong evidence of anharmonicity of the phonon-polariton response. Further evidence for anharmonicity comes from ISRS measurements at the fundamental wavevector and measurements of diffraction efficiency. The ISRS data shows non-sinusoidal response with a rich overtone spectrum, while the diffraction efficiency measurements reveal ionic displacements of about 1% of the ferroelectric distortion

  20. Stretch-minimising stream surfaces

    KAUST Repository

    Barton, Michael

    2015-05-01

    We study the problem of finding stretch-minimising stream surfaces in a divergence-free vector field. These surfaces are generated by motions of seed curves that propagate through the field in a stretch minimising manner, i.e., they move without stretching or shrinking, preserving the length of their arbitrary arc. In general fields, such curves may not exist. How-ever, the divergence-free constraint gives rise to these \\'stretch-free\\' curves that are locally arc-length preserving when infinitesimally propagated. Several families of stretch-free curves are identified and used as initial guesses for stream surface generation. These surfaces are subsequently globally optimised to obtain the best stretch-minimising stream surfaces in a given divergence-free vector field. Our algorithm was tested on benchmark datasets, proving its applicability to incompressible fluid flow simulations, where our stretch-minimising stream surfaces realistically reflect the flow of a flexible univariate object. © 2015 Elsevier Inc. All rights reserved.

  1. Acute Muscle Stretching and Shoulder Position Sense

    OpenAIRE

    Björklund, Martin; Djupsjöbacka, Mats; Crenshaw, Albert G

    2006-01-01

    Context: Stretching is common among athletes as a potential method for injury prevention. Stretching-induced changes in the muscle spindle properties are a suggested mechanism, which may imply reduced proprioception after stretching; however, little is known of this association.

  2. Resonance Spectrum Characteristics of Effective Electromechanical Coupling Coefficient of High-Overtone Bulk Acoustic Resonator

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-09-01

    Full Text Available A high-overtone bulk acoustic resonator (HBAR consisting of a piezoelectric film with two electrodes on a substrate exhibits a high quality factor (Q and multi-mode resonance spectrum. By analyzing the influences of each layer’s material and structure (thickness parameters on the effective electromechanical coupling coefficient (Keff2, the resonance spectrum characteristics of Keff2 have been investigated systematically, and the optimal design of HBAR has been provided. Besides, a device, corresponding to one of the theoretical cases studied, is fabricated and evaluated. The experimental results are basically consistent with the theoretical results. Finally, the effects of Keff2 on the function of the crystal oscillators constructed with HBARs are proposed. The crystal oscillators can operate in more modes and have a larger frequency hopping bandwidth by using the HBARs with a larger Keff2·Q.

  3. Near-near-infrared thermal lens spectroscopy to assess overtones and combination bands of sulfentrazone pesticide

    Science.gov (United States)

    Ventura, M.; Silva, J. R.; Andrade, L. H. C.; Scorza Júnior, R. P.; Lima, S. M.

    2018-01-01

    Thermal lens spectroscopy (TLS) in the near-near-infrared region was used to explore the absorptions of overtones and combination bands of sulfentrazone (SFZ) herbicide diluted in methanol. This spectroscopic region was chosen in order to guarantee that only thermal lens effect is noted during the experimental procedure. The results showed that it was possible to detect very low concentrations ( 2 ng/μL) of SFZ in methanol by determining its thermal diffusivity or the absorption coefficient due to the 3ν(NH) + 1δ(CH) combination band. This minimum SFZ concentration is the limit observed by chromatography method. The findings demonstrated that the TLS can be used for precise and accurate assessment of pesticides in ecosystems. Besides, the 3ν(NH) + 1δ(CH) combination band at 960 nm can be used as a marker for SFZ in methanol.

  4. Effect of hydrogen bonding on the infrared absorption intensity of OH stretch vibrations

    Science.gov (United States)

    Athokpam, Bijyalaxmi; Ramesh, Sai G.; McKenzie, Ross H.

    2017-05-01

    We consider how the infrared intensity of a hydrogen-bonded OH stretch varies from weak to strong H-bonds using a theoretical model. We obtain trends for the fundamental and overtone transition intensities as a function of the donor-acceptor distance, a common measure of H-bond strength. Building upon our earlier work using a two-diabatic state model, we introduce a Mecke function-based dipole moment for the H-bond and calculate transition moments using one-dimensional vibrational eigenstates along the H-atom transfer coordinate. The fundamental intensity is found to be over 20-fold enhanced for strong H-bonds, where non-Condon effects are significant. We analyse isotope effects, including the secondary geometric isotope effect. The first overtone intensity varies non-monotonically with H-bond strength; suppression occurs for weak bonds but strong enhancements are possible for strong H-bonds. We also study how these trends are affected by Mecke parameter variations. For a few specific dimers, we compare our results with earlier works.

  5. Origin of multiple periodicities in the Fourier power spectra of the Plasmodium falciparum genome

    Directory of Open Access Journals (Sweden)

    Nunes Miriam CS

    2011-12-01

    Full Text Available Abstract Background Fourier transforms and their associated power spectra are used for detecting periodicities and protein-coding genes and is generally regarded as a well established technique. Many of the periodicities which have been found with this method are quite well understood such as the periodicity of 3 nt which is associated to codon usage. But what is the origin of the peculiar frequency multiples k/21 which were reported for a tiny section of chromosome 2 in P. falciparum? Are these present in other chromosomes and perhaps in related organisms? And how should we interpret fractional periodicities in genomes? Results We applied the binary indicator power spectrum to all chromosomes of P. falciparum, and found that the frequency overtones k/21 are present only in non-coding sections. We did not find such frequency overtones in any other related genomes. Furthermore, the frequency overtones were identified as artifacts of the way the genome is encoded into a numerical sequence, that is, they are frequency aliases. By choosing a different way to encode the sequence the overtones do not appear. In view of these results, we revisited early applications of this technique to proteins where frequency overtones were reported. Conclusions Some authors hinted recently at the possibility of mapping artifacts and frequency aliases in power spectra. However, in the case of P. falciparum the frequency aliases are particularly strong and can mask the 1/3 frequency which is used for gene detecting. This shows that albeit being a well known technique, with a long history of application in proteins, few researchers seem to be aware of the problems represented by frequency aliases.

  6. Hydraulic fracture during epithelial stretching.

    Science.gov (United States)

    Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino; Trepat, Xavier

    2015-03-01

    The origin of fracture in epithelial cell sheets subject to stretch is commonly attributed to excess tension in the cells' cytoskeleton, in the plasma membrane, or in cell-cell contacts. Here, we demonstrate that for a variety of synthetic and physiological hydrogel substrates the formation of epithelial cracks is caused by tissue stretching independently of epithelial tension. We show that the origin of the cracks is hydraulic; they result from a transient pressure build-up in the substrate during stretch and compression manoeuvres. After pressure equilibration, cracks heal readily through actomyosin-dependent mechanisms. The observed phenomenology is captured by the theory of poroelasticity, which predicts the size and healing dynamics of epithelial cracks as a function of the stiffness, geometry and composition of the hydrogel substrate. Our findings demonstrate that epithelial integrity is determined in a tension-independent manner by the coupling between tissue stretching and matrix hydraulics.

  7. Soleus stretch reflex during cycling

    DEFF Research Database (Denmark)

    Grey, Michael James; Pierce, C. W.; Milner, T. E.

    2001-01-01

    the crank cycle, producing ankle dorsiflexion perturbations of similar trajectory. The stretch reflex was greatest during the power phase of the crank cycle and was decreased to the level of background EMG during recovery. Matched perturbations were induced under static conditions at the same crank angle...... active cycling as has been shown with the H-reflex. This lack of depression may reflect a decreased susceptibility of the stretch reflex to inhibition, possibly originating from presynaptic mechanisms....

  8. BETA SPECTRA. I. Negatrons spectra

    International Nuclear Information System (INIS)

    Grau Malonda, A.; Garcia-Torano, E.

    1978-01-01

    Using the Fermi theory of beta decay, the beta spectra for 62 negatrons emitters have been computed introducing a correction factor for unique forbidden transitions. These spectra are plotted vs. energy, once normal i sed, and tabulated with the related Fermi functions. The average and median energies are calculated. (Author)

  9. Relationship Between Stretch Duration And Shoulder Musculature ...

    African Journals Online (AJOL)

    To date, studies focussing on the effect of stretching on flexibility have focused almost solely on the effect of chronic stretching rather than the effects of acute stretching performed immediately prior to physical activity. The effects of different static stretches were assessed on passive shoulder range of motion (ROM).

  10. Atomic Stretch: Optimally bounded real-time stretching and beyond

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Nielsen, Jannik Boll

    2016-01-01

    Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color-modification, co......Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color...

  11. Vibration-rotational overtones absorption of solid hydrogens using optoacoustic spectroscopy technique

    International Nuclear Information System (INIS)

    Vieira, M.M.F.

    1985-01-01

    Vibrational-rotational overtones absorption solid hydrogens (H 2 , D 2 , HD) is studied using pulsed laser piezoeletric transducer (PULPIT) optoacoustic spectroscopy is studied. A general downward shift in energy from isolated molecular energies is observed. Studying normal-hydrogen it was observed that the phonon excitations associated with double-molecular transitions are predominantly transverse-optical phonons, whereas the excitations associated with single-molecular transitions are predominantly longitudinal - optical phonons. Multiplet structures were observed for certain double transitions in parahydrogen and orthodeuterium. The HD spectrum, besides presenting the sharp zero-phonon lines and the associated phonon side bands, like H 2 and D 2 , showed also two different features. This observation was common to all the transitions involving pure rotational excitation in H 2 and D 2 , which showed broad linewidths. This, together with some other facts (fluorescence lifetime *approx*10 5 sec; weak internal vibration and lattice coupling), led to the proposition of a mechanism for the fast nonradiative relaxation in solid hydrogens, implied from some observed experimental evidences. This relaxation, due to strong coupling, would happen in two steps: the internal vibration modes would relax to the rotational modes of the molecules, and then this rotational modes would relax to the lattice vibration modes. (Author) [pt

  12. Overtone Mobility Spectrometry: Part 4. OMS-OMS Analyses of Complex Mixtures

    Science.gov (United States)

    Kurulugama, Ruwan T.; Nachtigall, Fabiane M.; Valentine, Stephen J.; Clemmer, David E.

    2011-11-01

    A new, two-dimensional overtone mobility spectrometry (OMS-OMS) instrument is described for the analysis of complex peptide mixtures. OMS separations are based on the differences in mobilities of ions in the gas phase. The method utilizes multiple drift regions with modulated drift fields such that only ions with appropriate mobilities are transmitted to the detector. Here we describe a hybrid OMS-OMS combination that utilizes two independently operated OMS regions that are separated by an ion activation region. Mobility-selected ions from the first OMS region are exposed to energizing collisions and may undergo structural transitions before entering the second OMS region. This method generates additional peak capacity and allows for higher selectivity compared with the one-dimensional OMS method. We demonstrate the approach using a three-protein tryptic digest spiked with the peptide Substance P. The [M + 3H]3+ ion from Substance P can be completely isolated from other components in this complex mixture prior to introduction into the mass spectrometer.

  13. Acute effects of unilateral static stretching on handgrip strength of the stretched and non-stretched limb.

    Science.gov (United States)

    Jelmini, Jacob D; Cornwell, Andrew; Khodiguian, Nazareth; Thayer, Jennifer; Araujo, And John

    2018-02-16

    To determine the effects of an acute bout of unilateral static stretching on handgrip strength of both the stretched and non-stretched limb. It was reasoned that if the non-stretched limb experienced a decrease in force output, further evidence for a neural mechanism to explain a post-stretch force reduction would be obtained as no mechanical adaptation would have occurred. Thirty participants performed maximum voluntary unilateral handgrip contractions of both limbs before and after stretching the finger flexors of the strength-dominant side only. Each trial was assessed for peak force, muscle activity (iEMG), and rate of force generation. Following the stretching bout, peak force and iEMG decreased by 4.4% (p = 0.001) and 6.4% (p = 0.000) respectively in the stretched limb only. However, rate of force generation was significantly impaired in both the stretched (- 17.3%; p = 0.000) and non-stretched limbs (- 10.8%; p = 0.003) 1 min post-stretch, and remained similarly depressed for both limbs 15 min later. Acute stretching negatively impacts rate of force generation more than peak force. Moreover, a reduced rate of force generation from the non-stretched limb indicates the presence of a cross-over inhibitory effect through the nervous system, which provides additional evidence for a neural mechanism.

  14. Soleus stretch reflex during cycling

    DEFF Research Database (Denmark)

    Grey, Michael James; Pierce, C. W.; Milner, T. E.

    2001-01-01

    The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions durin...

  15. On the generalised stretch function

    Czech Academy of Sciences Publication Activity Database

    Kharlamov, Alexander A.; Filip, Petr

    2012-01-01

    Roč. 21, č. 4 (2012), s. 272-278 ISSN 1022-1344 R&D Projects: GA ČR GA103/09/2066 Institutional research plan: CEZ:AV0Z20600510 Keywords : molecular length * recurrence equations * rubber * strain * stretch functions Subject RIV: BK - Fluid Dynamics Impact factor: 1.606, year: 2012

  16. Optical tweezers stretching of chromatin

    NARCIS (Netherlands)

    Pope, L.H.; Bennink, Martin L.; Greve, Jan

    2003-01-01

    Recently significant success has emerged from exciting research involving chromatin stretching using optical tweezers. These experiments, in which a single chromatin fibre is attached by one end to a micron-sized bead held in an optical trap and to a solid surface or second bead via the other end,

  17. Transient filament stretching rheometer II

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1997-01-01

    The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

  18. Biaxial stretching of polyethylene, (2)

    International Nuclear Information System (INIS)

    Sakami, Hiroshi; Iida, Shozo

    1976-01-01

    The mechanism of oriented crystallization in mutually perpendicular direction to each other was investigated on the crosslinked linear polyethylene stretched successively and biaxially above melting point of raw material. To investigate the mechanism, the shrinkage stress, the degree of polarization and DSC of the film at the fixed length were measured on the crystallization process. The behavior observed on crystallization could be divided into that in the first period and that in the second period. The first period showed the domain of highly oriented crystallization of the crosslinked molecular chain, and in the second period the fold type crystals grew with highly oriented crystals in the first period as nuclear. Therefore, the formation of bi-component crystal structure is supposed for the crystallization. The biaxially oriented crystallization proceeded as follows: the uniaxial orientation to MD was observed in the first stretching in the initial stage, and then the further processing by the second stretching at a right angle caused the fold type crystallization of molecular chain oriented to TD. The film stretched fully and biaxially could be considered to have the oriented crystalline structure in which highly oriented fibril crystals and fold type crystals distribute at random. (auth.)

  19. Time stretch and its applications

    Science.gov (United States)

    Mahjoubfar, Ata; Churkin, Dmitry V.; Barland, Stéphane; Broderick, Neil; Turitsyn, Sergei K.; Jalali, Bahram

    2017-06-01

    Observing non-repetitive and statistically rare signals that occur on short timescales requires fast real-time measurements that exceed the speed, precision and record length of conventional digitizers. Photonic time stretch is a data acquisition method that overcomes the speed limitations of electronic digitizers and enables continuous ultrafast single-shot spectroscopy, imaging, reflectometry, terahertz and other measurements at refresh rates reaching billions of frames per second with non-stop recording spanning trillions of consecutive frames. The technology has opened a new frontier in measurement science unveiling transient phenomena in nonlinear dynamics such as optical rogue waves and soliton molecules, and in relativistic electron bunching. It has also created a new class of instruments that have been integrated with artificial intelligence for sensing and biomedical diagnostics. We review the fundamental principles and applications of this emerging field for continuous phase and amplitude characterization at extremely high repetition rates via time-stretch spectral interferometry.

  20. BSDB: the Biomolecule Stretching Database

    Science.gov (United States)

    Cieplak, Marek; Sikora, Mateusz; Sulkowska, Joanna I.; Witkowski, Bartlomiej

    2011-03-01

    Despite more than a decade of experiments on single biomolecule manipulation, mechanical properties of only several scores of proteins have been measured. A characteristic scale of the force of resistance to stretching, Fmax , has been found to range between ~ 10 and 480 pN. The Biomolecule Stretching Data Base (BSDB) described here provides information about expected values of Fmax for, currently, 17 134 proteins. The values and other characteristics of the unfolding proces, including the nature of identified mechanical clamps, are available at www://info.ifpan.edu.pl/BSDB/. They have been obtained through simulations within a structure-based model which correlates satisfactorily with the available experimental data on stretching. BSDB also lists experimental data and results of the existing all-atom simulations. The database offers a Protein-Data-Bank-wide guide to mechano-stability of proteins. Its description is provided by a forthcoming Nucleic Acids Research paper. Supported by EC FUNMOL project FP7-NMP-2007-SMALL-1, and European Regional Development Fund: Innovative Economy (POIG.01.01.02-00-008/08).

  1. Stretching

    Science.gov (United States)

    ... this topic for: Teens Dehydration Safety Tips: Running Knee Injuries Repetitive Stress Injuries Sports and Exercise Safety Dealing With Sports Injuries Sports Center Strains and Sprains View more Partner Message About Us Contact Us ...

  2. RF discharge slab carbon monoxide laser: overtone lasing (2.5-4.0 micron) and fundamental band tuning (5.0-6.5 micron)

    Science.gov (United States)

    Ionin, Andrey A.; Kozlov, Andrey Yu.; Seleznev, Leonid V.; Sinitsyn, Dmitry V.

    2008-10-01

    Overtone lasing and fundamental band tuning was for the first time obtained in a slab carbon monoxide laser. The compact slab CO laser with active volume 3×30×250 mm3 was excited by a repetitively pulsed capacitive RF discharge (81.36 MHz) with pulse repetition rate 100-500 Hz. The laser electrodes were cooled down to 120 K. Gas mixture CO:Air:He at gas pressures 15-22 Torr was used. An optical scheme "frequency selective master oscillator - laser amplifier" was applied for getting fundamental band tuning. Single line lasing with average power up to several tens of mW was observed on ~100 rotational-vibrational transitions of CO molecule within the spectral range ~5.0 - 6.5 micron. Multiline overtone lasing was observed on ~80 spectral lines within the spectral range ~2.5 -4.0 micron, with maximum single line average output power 12 mW. Total output power of the slab overtone CO laser came up to 0.3 W, with maximum laser efficiency 0.5%. Results of parametric studies of the overtone CO laser including complicated time behavior for laser pulses on different overtone vibrational-rotational transitions are discussed.

  3. Mixed quantum/classical approach to OH-stretch inelastic incoherent neutron scattering spectroscopy for ambient and supercooled liquid water and ice Ih

    International Nuclear Information System (INIS)

    Shi, L.; Skinner, J. L.

    2015-01-01

    OH-stretch inelastic incoherent neutron scattering (IINS) has been measured to determine the vibrational density of states (VDOS) in the OH-stretch region for liquid water, supercooled water, and ice Ih, providing complementary information to IR and Raman spectroscopies about hydrogen bonding in these phases. In this work, we extend the combined electronic-structure/molecular-dynamics (ES/MD) method, originally developed by Skinner and co-workers to simulate OH-stretch IR and Raman spectra, to the calculation of IINS spectra with small k values. The agreement between theory and experiment in the limit k → 0 is reasonable, further validating the reliability of the ES/MD method in simulating OH-stretch spectroscopy in condensed phases. The connections and differences between IINS and IR spectra are analyzed to illustrate the advantages of IINS over IR in estimating the OH-stretch VDOS

  4. Effect of stretching techniques on hamstring flexibility in female ...

    African Journals Online (AJOL)

    Flexibility can be achieved by a variety of stretching techniques and the benefits of stretching are known. However, controversy remains about the best type of stretching for achieving a particular goal or outcome. The four most basic stretches are static stretching, dynamic stretching, PNF hold-relax and PNF contract-relax ...

  5. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  6. Stretching of macromolecules and proteins

    International Nuclear Information System (INIS)

    Strick, T R; Dessinges, M-N; Charvin, G; Dekker, N H; Allemand, J-F; Bensimon, D; Croquette, V

    2003-01-01

    In this paper we review the biophysics revealed by stretching single biopolymers. During the last decade various techniques have emerged allowing micromanipulation of single molecules and simultaneous measurements of their elasticity. Using such techniques, it has been possible to investigate some of the interactions playing a role in biology. We shall first review the simplest case of a non-interacting polymer and then present the structural transitions in DNA, RNA and proteins that have been studied by single-molecule techniques. We shall explain how these techniques permit a new approach to the protein folding/unfolding transition

  7. Overtone-based pitch selection in hermit thrush song: unexpected convergence with scale construction in human music.

    Science.gov (United States)

    Doolittle, Emily L; Gingras, Bruno; Endres, Dominik M; Fitch, W Tecumseh

    2014-11-18

    Many human musical scales, including the diatonic major scale prevalent in Western music, are built partially or entirely from intervals (ratios between adjacent frequencies) corresponding to small-integer proportions drawn from the harmonic series. Scientists have long debated the extent to which principles of scale generation in human music are biologically or culturally determined. Data from animal "song" may provide new insights into this discussion. Here, by examining pitch relationships using both a simple linear regression model and a Bayesian generative model, we show that most songs of the hermit thrush (Catharus guttatus) favor simple frequency ratios derived from the harmonic (or overtone) series. Furthermore, we show that this frequency selection results not from physical constraints governing peripheral production mechanisms but from active selection at a central level. These data provide the most rigorous empirical evidence to date of a bird song that makes use of the same mathematical principles that underlie Western and many non-Western musical scales, demonstrating surprising convergence between human and animal "song cultures." Although there is no evidence that the songs of most bird species follow the overtone series, our findings add to a small but growing body of research showing that a preference for small-integer frequency ratios is not unique to humans. These findings thus have important implications for current debates about the origins of human musical systems and may call for a reevaluation of existing theories of musical consonance based on specific human vocal characteristics.

  8. Vibrational spectroscopy of Cm–C/Cb–Cb stretching vibrations of ...

    Indian Academy of Sciences (India)

    operator which conveniently describes stretching vibrations of biomolecules. For a copper tetramesityl porphyrin molecule, the higher excited vibrational levels are calculated by applying the U(2) algebraic approach. Keywords. Lie algebraic techniques; vibrational spectra; copper tetramesityl porphyrin. PACS Nos 31.65.

  9. PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING VERSUS STATIC STRETCHING ON SPRINTING PERFORMANCE AMONG COLLEGIATE SPRINTERS

    Directory of Open Access Journals (Sweden)

    Jayaram Maharjan

    2015-08-01

    Full Text Available Background: A warm-up is important part of preparation for sprinting. There is popularity of doing stretching as part of warm up before athletic activity. The static stretching and PNF stretching is performed by athletes but their effectiveness on sprinting performance is in state of debate. The objective is to determine the effect of static stretching and PNF stretching on sprinting performance in college sprinters and to compare the effects of PNF stretching over static stretching on sprinting performance in college sprinters. Method: A total of 100 subjects were taken for the study that fulfill the inclusion criteria and all were divided into group- A (static stretching and group- B (PNF stretching by simple random sampling method. Both the groups received 5 minutes of warm-up exercises. Pre-Post design was used, which consisted of running a 40-yard sprint immediately following 2 stretching conditions aimed at the lower limb muscles Results: In static stretching group sprint time changed from 6.55 with standard deviation of 0.93 to 6.12 with standard deviation of 1.02 (P.605. Conclusion: Hence both static stretching and PNF stretching can be performed before sprinting activity to improve the sprinting performance.

  10. Contact angles on stretched solids

    Science.gov (United States)

    Mensink, Liz; Snoeijer, Jacco

    2017-11-01

    The surface energy of solid interfaces plays a central role in wetting, as they dictate the liquid contact angle. Yet, it has been challenging to measure the solid surface energies independently, without making use of Young's law. Here we present Molecular Dynamics (MD) simulations by which we measure the surface properties for all interfaces, including the solids. We observe change in contact angles upon stretching the solid substrates, showing that the surface energy is actually strain dependent. This is clear evidence of the so-called Shuttleworth effect, making it necessary to distinguish surface energy from surface tension. We discuss how this effect gives rise to a new class of elasto-capillary phenomena. ERC Consolidator Grant No. 616918.

  11. A COMPARISION BETWEEN CROSSBODY STRETCH VERSUS SLEEPER STRETCH IN PERIARTHRITIS OF SHOULDER

    Directory of Open Access Journals (Sweden)

    Shaik Raheem Saheb

    2015-12-01

    Full Text Available Background: Recently Cross body stretch and Sleeper stretch are used to improve internal rotation Range of motion in Shoulder Pathologies. It was proposed to study the effect of cross body stretch and sleeper stretch in subjects with periarthritis of shoulder. Methods: 60 subjects with a mean age of 53 years having clinical diagnosis of Periarthritis of shoulder and full filled the inclusive criteria are taken. After the initial measurements, the subjects are randomly assigned into 2 stretching groups. Group-A performed the Sleeper stretch. Group-B performed a Cross body stretch. Both Groups performed the Stretch in Duration of 6weeks – once daily for 5 repetitions holding each stretch for 30 seconds for 5 days a week. Along with this technique conventional physiotherapy like IFT, overhead pulleys, Pendula exercises, Wall climbing exercises, mariners wheel exercises are performed. After the treatment, subjects were evaluated for their pain profile using visual analogue scale, Goniometer for measuring Range of motion. Results: For within group comparison we used Paired t-test analysis, For Between group comparison we used Independent t-test for statistical analysis. At the end of 6 weeks It was found that subjects treated with cross-body stretch showed significant improvement in terms of VAS scores and Range of motion scores (P=0.000 and patients treated with Sleeper stretch showed significant improvement in terms of VAS scores and Range of motion scores (P=0.000. When compared between Groups the VAS and Range of motion scores showed a significant improvement in Cross body stretch Group than the Sleeper stretch Group (P=0.000. Conclusion: It was concluded that both stretching techniques were found improvement in Range of motion and VAS and Cross-body Stretch showed more Significant improvement than the sleeper Stretch after 6 weeks treatment.

  12. Anharmonic Bend-Stretch Coupling in Water

    NARCIS (Netherlands)

    Lindner, Jörg; Vöhringer, Peter; Pshenichnikov, Maxim S.; Cringus, Dan; Wiersma, Douwe A.; Corkum, Paul; Jonas, David M.; Miller, R.J. Dwayne.; Weiner, Andrew M.

    2006-01-01

    Following excitation of the H-O-H bending mode of water molecules in solution the stretching mode region is monitored over its entire width. The anharmonic coupling between the two modes results in a substantial change of the transient stretch absorption that decays with the bend depopulation time.

  13. Infrared laser spectroscopy of the n-propyl and i-propyl radicals: Stretch-bend Fermi coupling in the alkyl CH stretch region

    Science.gov (United States)

    Franke, Peter R.; Tabor, Daniel P.; Moradi, Christopher P.; Douberly, Gary E.; Agarwal, Jay; Schaefer, Henry F.; Sibert, Edwin L.

    2016-12-01

    The n-propyl and i-propyl radicals were generated in the gas phase via pyrolysis of n-butyl nitrite [CH3(CH2)3ONO] and i-butyl nitrite [(CH3)2CHCH2ONO], respectively. Nascent radicals were promptly solvated by a beam of He nanodroplets, and the infrared spectra of the radicals were recorded in the CH stretching region. Several previously unreported bands are observed between 2800 and 3150 cm-1. The CH stretching modes observed above 3000 cm-1 are in excellent agreement with CCSD(T) anharmonic frequencies computed using second-order vibrational perturbation theory. However, between 2800 and 3000 cm-1, the spectra of n- and i-propyl radicals become congested and difficult to assign due to the presence of multiple anharmonic resonance polyads. To model the spectrally congested region, Fermi and Darling-Dennison resonances are treated explicitly using "dressed" Hamiltonians and CCSD(T) quartic force fields in the normal mode representation, and the agreement with experiment is less than satisfactory. Computations employing local mode effective Hamiltonians reveal the origin of the spectral congestion to be strong coupling between the high frequency CH stretching modes and the lower frequency CHn bending/scissoring motions. The most significant coupling is between stretches and bends localized on the same CH2/CH3 group. Spectral simulations using the local mode approach are in excellent agreement with experiment.

  14. Anisotropic instability of a stretching film

    Science.gov (United States)

    Xu, Bingrui; Li, Minhao; Deng, Daosheng

    2017-11-01

    Instability of a thin liquid film, such as dewetting arising from Van der Waals force, has been well studied, and is typically characterized by formation of many droplets. Interestingly, a thin liquid film subjected to an applied stretching during a process of thermal drawing is evolved into an array of filaments, i.e., continuity is preserved along the direction of stretching while breakup occurs exclusively in the plane of cross section. Here, to understand this anisotropic instability, we build a physical model by considering both Van der Waals force and the effect of stretching. By using the linear instability analysis method and then performing a numerical calculation, we find that the growth rate of perturbations at the cross section is larger than that along the direction of stretching, resulting in the anisotropic instability of the stretching film. These results may provide theoretical guidance to achieve more diverse structures for nanotechnology.

  15. Strategy as stretch and leverage.

    Science.gov (United States)

    Hamel, G; Prahalad, C K

    1993-01-01

    Global competition is not just product versus product or company versus company. It is mind-set versus mind-set. Driven to understand the dynamics of competition, we have learned a lot about what makes one company more successful than another. But to find the root of competitiveness--to understand why some companies create new forms of competitive advantage while others watch and follow--we must look at strategic mind-sets. For many managers, "being strategic" means pursuing opportunities that fit the company's resources. This approach is not wrong, Gary Hamel and C.K. Prahalad contend, but it obscures an approach in which "stretch" supplements fit and being strategic means creating a chasm between ambition and resources. Toyota, CNN, British Airways, Sony, and others all displaced competitors with stronger reputations and deeper pockets. Their secret? In each case, the winner had greater ambition than its well-endowed rivals. Winners also find less resource-intensive ways of achieving their ambitious goals. This is where leverage complements the strategic allocation of resources. Managers at competitive companies can get a bigger bang for their buck in five basic ways: by concentrating resources around strategic goals; by accumulating resources more efficiently; by complementing one kind of resource with another; by conserving resources whenever they can; and by recovering resources from the market-place as quickly as possible. As recent competitive battles have demonstrated, abundant resources can't guarantee continued industry leadership.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten

    2016-03-01

    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

  17. Effect of modified hold-relax stretching and static stretching on hamstring muscle flexibility.

    Science.gov (United States)

    Ahmed, Hashim; Iqbal, Amir; Anwer, Shahnawaz; Alghadir, Ahmad

    2015-02-01

    [Purpose] The aim of present study was to compare the effectiveness of modified hold-relax stretching and static stretching in improving the hamstring muscle flexibility. [Subjects and Methods] Forty-five male subjects with hamstring tightness were included in this study. The subjects were randomly placed into three groups: the modified hold-relax stretching, static stretching and control groups. The modified hold-relax stretching group performed 7 seconds of isometric contraction and then relaxed for 5 seconds, and this was repeated five times daily for five consecutive days. The static stretching group received 10 minutes of static stretching with the help of a pulley and weight system for five consecutive days. The control group received only moist heat for 20 minutes for five consecutive days. A baseline reading of passive knee extension (PKE) was taken prior to the intervention; rest measurements were taken immediate post intervention on day 1, day 3, day 5, and after a 1 week follow-up, i.e., at the 12th day. [Results] On comparing the baseline readings of passive knee extension (PKE), there was no difference noted between the three groups. On comparing the posttest readings on day 5 between the 3 groups, a significant difference was noted. However, post hoc analysis revealed an insignificant difference between the modified hold-relax stretching and static stretching groups. There was a significant difference between the static stretching and control groups and between the modified hold-relax stretching and control groups. [Conclusion] The results of this study indicate that both the modified hold-relax stretching technique and static stretching are equally effective, as there was no significant difference in improving the hamstring muscle flexibility between the two groups.

  18. Investing in a Large Stretch Press

    Science.gov (United States)

    Choate, M.; Nealson, W.; Jay, G.; Buss, W.

    1986-01-01

    Press for forming large aluminum parts from plates provides substantial economies. Study assessed advantages and disadvantages of investing in large stretch-forming press, and also developed procurement specification for press.

  19. Excluded Volume Effects in Gene Stretching

    OpenAIRE

    Lam, Pui-Man

    2002-01-01

    We investigate the effects excluded volume on the stretching of a single DNA in solution. We find that for small force F, the extension h is not linear in F but proportion to F^{\\chi}, with \\chi=(1-\

  20. DNA stretching on functionalized gold surfaces.

    OpenAIRE

    Zimmermann, R M; Cox, E C

    1994-01-01

    We describe a method for anchoring bacteriophage lambda DNA by one end to gold by Au-biotin-streptavidin-biotin-DNA bonds. DNA anchored to a microfabricated Au line could be aligned and stretched in flow and electric fields. The anchor was shown to resist a force of at least 11 pN, a linkage strong enough to allow DNA molecules of chromosome size to be stretched and aligned.

  1. Comparison of two stretching methods and optimization of stretching protocol for the piriformis muscle.

    Science.gov (United States)

    Gulledge, Brett M; Marcellin-Little, Denis J; Levine, David; Tillman, Larry; Harrysson, Ola L A; Osborne, Jason A; Baxter, Blaise

    2014-02-01

    Piriformis syndrome is an uncommon diagnosis for a non-discogenic form of sciatica whose treatment has traditionally focused on stretching the piriformis muscle (PiM). Conventional stretches include hip flexion, adduction, and external rotation. Using three-dimensional modeling, we quantified the amount of (PiM) elongation resulting from two conventional stretches and we investigated by use of a computational model alternate stretching protocols that would optimize PiM stretching. Seven subjects underwent three CT scans: one supine, one with hip flexion, adduction, then external rotation (ADD stretch), and one with hip flexion, external rotation, then adduction (ExR stretch). Three-dimensional bone models were constructed from the CT scans. PiM elongation during these stretches, femoral neck inclination, femoral head anteversion, and trochanteric anteversion were measured. A computer program was developed to map PiM length over a range of hip joint positions and was validated against the measured scans. ExR and ADD stretches elongated the PiM similarly by approximately 12%. Femoral head and greater trochanter anteversion influenced PiM elongation. Placing the hip joints in 115° of hip flexion, 40° of external rotation and 25° of adduction or 120° of hip flexion, 50° of external rotation and 30° of adduction increased PiM elongation by 30-40% compared to conventional stretches (15.1 and 15.3% increases in PiM muscle length, respectively). ExR and ADD stretches elongate the PiM similarly and therefore may have similar clinical effectiveness. The optimized stretches led to larger increases in PiM length and may be more easily performed by some patients due to increased hip flexion. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  2. Effects of proprioceptive neuromuscular facilitation stretching and static stretching on maximal voluntary contraction.

    Science.gov (United States)

    Miyahara, Yutetsu; Naito, Hisashi; Ogura, Yuji; Katamoto, Shizuo; Aoki, Junichiro

    2013-01-01

    This study was undertaken to investigate and compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and static stretching on maximal voluntary contraction (MVC). Thirteen male university students (age, 20 ± 1 years; height, 172.2 ± 4.6 cm; weight, 68.4 ± 6.7 kg; mean ± SD) completed 3 different conditions on 3 nonconsecutive days in randomized order: static stretching (SS), PNF stretching (PNF), and no stretching (control, CON). Each condition consisted of a 5-minute rest accompanied by one of the following activities: (a) control, (b) SS, or (c) PNF stretching. The hip flexion range of motion (ROM) was evaluated immediately before and after the activity. The MVC of knee flexion was then measured. Surface electromyography was recorded from the biceps femoris and vastus lateralis muscles during MVC tests and stretching. Although increases in ROM were significantly greater after PNF than after SS (p < 0.01), the decreases in MVC were similar between the 2 treatments. These results suggest that, although PNF stretching increases ROM more than SS, PNF stretching and SS is detrimental to isometric maximal strength.

  3. DNA-wrapped carbon nanotubes aligned in stretched gelatin films: Polarized resonance Raman and absorption spectroscopy study

    Science.gov (United States)

    Glamazda, A. Yu.; Plokhotnichenko, A. M.; Leontiev, V. S.; Karachevtsev, V. A.

    2017-09-01

    We present the study of DNA-wrapped single-walled carbon nanotubes (SWNTs) embedded in the stretched gelatin film by the polarized resonance Raman spectroscopy and visible-NIR optical absorption. The polarized dependent absorption spectra taken along and normal to the stretching direction demonstrate a comparatively high degree of the alignment of isolated SWNTs in the gelatin matrix. The analysis of Raman spectra of isolated SWNTs in the gelatin stretched films showed that the degree of the alignment of carbon nanotubes along the stretching direction is about 62%. The dependence of the peak position of G+-band in Raman spectra on the polarization angle θ between the polarization of the incident light and the direction of the stretching of films was revealed. This shift is explained by the different polarization dependence of the most intensive A and E1 symmetry modes within the G+-band. The performed studies of embedded DNA-wrapped nanotubes in the gelatin film show the simple method for obtaining the controlled ordered biocompatible nanotubes inside a polymer matrix. It can be used for manufacturing sizable flexible self-transparent films with integrated nanoelectrodes.

  4. Stretched-State Excitations with the

    Science.gov (United States)

    Garcia, Luis Alberto Casimiro

    Neutron time-of-fight spectra were obtained for the ^{14}C(p,n) ^{14}N, ^{18 }O(p,n)^{18}F, and ^{30}Si(p,n) ^{30}P reactions at 135 MeV with the beam-swinger system at the Indiana University Cyclotron Facility. Excitation-energy spectra and the differential cross sections for the observed excitations in these reactions were extracted over the momentum transfer range from 0 to 2.7 fm^{-1}. The primary goal of this work was to obtain the strengths and distributions for the "stretched" states. The identification of these states was based on comparisons of the theoretical differential cross sections, performed in a DWIA formalism, with the experimental cross sections. Isospin assignments were based primarily on comparisons of the measured (p,n) and (e,e^') spectroscopic strengths. Candidate (pid_ {5/2},nu{rm p}_sp {3/2}{-1}), J^ pi = 4 ^- T = 0, 1 and 2, 1 hbaromega states, were identified at E_{x} = 8.5, 13.8, 19.5, and 26.7 MeV in the ^{14}C(p,n) ^{14}N reaction, and the corresponding isovector strengths were extracted. The observed 4^--state excitation energies and the strengths are in good agreement with the analog T = 1 and 2, 4^--states observed in the (e,e^') reaction. Large -basis shell-model calculations were found to predict reasonably well the excitation energies; however, these calculations overpredict the strength by a factor of 2, for the T = 1 and 2 components. In the ^{18}O(p,n) ^{18}F reaction at 135 MeV, (pi d_{5/2},nu {rm d}_sp{5/2}{-1 }) 5^+ T = 0 0hbaromega strength was observed, concentrated in a single state, at E_{x} = 1.1 MeV, with 75% of the extreme-single-particle-model (ESPM) strength, in good agreement with a shell-model calculation. No 6^- 1hbaromega strength was observed in this reaction. Candidate (pi {rm d}_{5/2},nu p _sp{3/2}{-1}) J ^pi = 4^- T = 0, 1 and 2, 1hbaromega states, were identified at E_{x} = 3.9, 9.4, 10.2, 11.4, 12.0, 14.4, 15.3, 17.3, 18.0, 19.7, 21.4, and 23.4 MeV. The observed 4^- T = 2 state excitation energies and

  5. Comparison of active stretching technique and static stretching technique on hamstring flexibility.

    Science.gov (United States)

    Meroni, Roberto; Cerri, Cesare Giuseppe; Lanzarini, Carlo; Barindelli, Guido; Morte, Giancesare Della; Gessaga, Viviana; Cesana, Gian Carlo; De Vito, Giovanni

    2010-01-01

    To compare a passive and an active stretching technique to determine which one would produce and maintain the greatest gain in hamstring flexibility. To determine whether a passive or an active stretching technique results in a greater increase in hamstring flexibility and to compare whether the gains are maintained. Randomized controlled trial. Institutional. Sixty-five volunteer healthy subjects completed the enrollment questionnaire, 33 completed the required 75% of the treatment after 6 weeks, and 22 were assessed 4 weeks after the training interruption. A 6-week stretching program with subjects divided into 2 groups with group 1 performing active stretching exercises and group 2 performing passive stretching exercises. Range of motion (ROM) was measured after 3 and 6 weeks of training and again 4 weeks after the cessation of training and compared with the initial measurement. After 3 weeks of training, the mean gain in group 1 (active stretching) on performing the active knee extension range of motion (AKER) test was 5.7 degrees, whereas the mean gain in group 2 (passive stretching) was 3 degrees (P = .015). After 6 weeks of training, the mean gain in group 1 was 8.7 degrees , whereas the mean gain in group 2 was 5.3 degrees (P = .006). Twenty-two subjects were reassessed 4 weeks after the cessation of the training with the maintained gain of ROM in group 1 being 6.3 degrees , whereas the maintained gain in group 2 was 0.1 degrees (P = .003). Active stretching produced the greater gain in the AKER test, and the gain was almost completely maintained 4 weeks after the end of the training, which was not seen with the passive stretching group. Active stretching was more time efficient compared with the static stretching and needed a lower compliance to produce effects on flexibility.

  6. Spectrum of OH-stretching vibrations of water in a "floating" water bridge

    Science.gov (United States)

    Oshurko, V. B.; Ropyanoi, A. A.; Fedorov, A. N.; Fedosov, M. V.; Shelaeva, N. A.

    2012-11-01

    The axial distribution (over the cross section) of the spectra of the OH-stretching band of water in a water bridge is investigated using the Raman scattering method. It is found that the axial structure of the bridge is inhomogeneous: the core at the center of the bridge contains a larger amount of water with an "icelike" structure and a presumably larger number of H+ ions, while the outer layer probably consists of water with a larger number of OH- ions.

  7. Resonance Raman spectra of wurtzite and zincblende CdSe nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, Anne Myers, E-mail: amkelley@ucmerced.edu [Chemistry and Chemical Biology, School of Natural Sciences, University of California, 5200 North Lake Road, Merced, CA 95343 (United States); Dai, Quanqin; Jiang, Zhong-jie; Baker, Joshua A.; Kelley, David F. [Chemistry and Chemical Biology, School of Natural Sciences, University of California, 5200 North Lake Road, Merced, CA 95343 (United States)

    2013-08-30

    Highlights: ► Very similar resonance Raman spectra of wurtzite and zincblende CdSe nanocrystals. ► First absolute resonance Raman cross-sections reported for CdSe nanocrystals. ► LO overtones suggest slightly stronger electron–phonon coupling in wurtzite form. - Abstract: Resonance Raman spectra and absolute differential Raman cross-sections have been measured for CdSe nanocrystals in both the wurtzite and zincblende crystal forms at four excitation wavelengths from 457.9 to 514.5 nm. The frequency and bandshape of the longitudinal optical (LO) phonon fundamental is essentially identical for both crystal forms at each excitation wavelength. The LO phonon overtone to fundamental intensity ratio appears to be slightly higher for the wurtzite form, which may suggest slightly stronger exciton–phonon coupling from the Fröhlich mechanism in the wurtzite form. The LO fundamental Raman cross-sections are very similar for both crystal forms at each excitation wavelength.

  8. Structural information from OH stretching frequencies—V. On the presence of different rotamers in substituted tertiary cyclohexanol compounds

    NARCIS (Netherlands)

    Lutz, E.T.G.; Maas, J.H. van der

    1980-01-01

    The presence of different hydroxyl rotamers in a number of saturated aequatorial and axial tertiary cyclohexanols has been studied by means of the i.r. spectra of the OH stretching band. Band resolving experiments indicate that an OH positioned over a cyclohexylring contributes appreciably to the

  9. How to determine local stretching and tension in a flow-stretched DNA molecule

    DEFF Research Database (Denmark)

    Pedersen, Jonas Nyvold; Marie, Rodolphe; Kristensen, Anders

    2016-01-01

    We determine the nonuniform stretching of and tension in amega base pairs-long fragment of deoxyribonucleic acid (DNA) that is flow stretched in a nanofluidic chip. We use no markers, do not know the contour length of the DNA, and do not have the full DNA molecule inside our field of view. Instead...

  10. CURRENT CONCEPTS IN MUSCLE STRETCHING FOR EXERCISE AND REHABILITATION

    Science.gov (United States)

    2012-01-01

    Stretching is a common activity used by athletes, older adults, rehabilitation patients, and anyone participating in a fitness program. While the benefits of stretching are known, controversy remains about the best type of stretching for a particular goal or outcome. The purpose of this clinical commentary is to discuss the current concepts of muscle stretching interventions and summarize the evidence related to stretching as used in both exercise and rehabilitation. PMID:22319684

  11. CURRENT CONCEPTS IN MUSCLE STRETCHING FOR EXERCISE AND REHABILITATION

    OpenAIRE

    Page, Phil

    2012-01-01

    Stretching is a common activity used by athletes, older adults, rehabilitation patients, and anyone participating in a fitness program. While the benefits of stretching are known, controversy remains about the best type of stretching for a particular goal or outcome. The purpose of this clinical commentary is to discuss the current concepts of muscle stretching interventions and summarize the evidence related to stretching as used in both exercise and rehabilitation.

  12. Summary of the stretching tectonics research

    International Nuclear Information System (INIS)

    Yu Dagan

    1994-01-01

    The rise of stretching tectonics is established on the basis of recent structural geology theory, the establishment of metamorphic nucleus complex structural model on one hand plays an important promoting art to the development of stretching structure, on the other hand, it needs constant supplement and perfection in practice. Metamorphic nucleus complex is the carrier of comparatively deep geological information in vertical section of the crust and has wide distribution in the era of south China. Evidently, it can be taken as the 'key' to understanding the deep and studying the basement, Strengthening the study will play the important promoting role to the deep prospecting. The study of stretching tectonics is not only limited within the range of structure and metamorphism, but combine with the studies of sedimentation, magmatism, metamorphism and mineralization, thus form a new field of tectonic geology of self-developing system

  13. Optofluidic time-stretch microscopy: recent advances

    Science.gov (United States)

    Lei, Cheng; Nitta, Nao; Ozeki, Yasuyuki; Goda, Keisuke

    2018-04-01

    Flow cytometry is an indispensable method for valuable applications in numerous fields such as immunology, pathology, pharmacology, molecular biology, and marine biology. Optofluidic time-stretch microscopy is superior to conventional flow cytometry methods for its capability to acquire high-quality images of single cells at a high-throughput exceeding 10,000 cells per second. This makes it possible to extract copious information from cellular images for accurate cell detection and analysis with the assistance of machine learning. Optofluidic time-stretch microscopy has proven its effectivity in various applications, including microalga-based biofuel production, evaluation of thrombotic disorders, as well as drug screening and discovery. In this review, we discuss the principles and recent advances of optofluidic time-stretch microscopy.

  14. Optofluidic time-stretch quantitative phase microscopy.

    Science.gov (United States)

    Guo, Baoshan; Lei, Cheng; Wu, Yi; Kobayashi, Hirofumi; Ito, Takuro; Yalikun, Yaxiaer; Lee, Sangwook; Isozaki, Akihiro; Li, Ming; Jiang, Yiyue; Yasumoto, Atsushi; Di Carlo, Dino; Tanaka, Yo; Yatomi, Yutaka; Ozeki, Yasuyuki; Goda, Keisuke

    2018-03-01

    Innovations in optical microscopy have opened new windows onto scientific research, industrial quality control, and medical practice over the last few decades. One of such innovations is optofluidic time-stretch quantitative phase microscopy - an emerging method for high-throughput quantitative phase imaging that builds on the interference between temporally stretched signal and reference pulses by using dispersive properties of light in both spatial and temporal domains in an interferometric configuration on a microfluidic platform. It achieves the continuous acquisition of both intensity and phase images with a high throughput of more than 10,000 particles or cells per second by overcoming speed limitations that exist in conventional quantitative phase imaging methods. Applications enabled by such capabilities are versatile and include characterization of cancer cells and microalgal cultures. In this paper, we review the principles and applications of optofluidic time-stretch quantitative phase microscopy and discuss its future perspective. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Bias of purine stretches in sequenced chromosomes

    DEFF Research Database (Denmark)

    Ussery, David; Soumpasis, Dikeos Mario; Brunak, Søren

    2002-01-01

    We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we...... measured the fraction of each genome which contains purine (or pyrimidine) tracts of lengths of 10 by or longer (hereafter referred to as 'purine tracts'), as well as stretches of alternating pyrimidines/purine ('pyr/pur tracts') of the same length. Using this criteria, a random sequence would be expected...... to contain 1.0% of purine tracts and also 1.0% of the alternating pyr/pur tracts. In the vast majority of cases, there are more purine tracts than would be expected from a random sequence, with an average of 3.5%, significantly larger than the expectation value. The fraction of the chromosomes containing pyr...

  16. Bias of purine stretches in sequenced chromosomes

    DEFF Research Database (Denmark)

    Ussery, David; Soumpasis, Dikeos Mario; Brunak, Søren

    2002-01-01

    We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we...... to contain 1.0% of purine tracts and also 1.0% of the alternating pyr/pur tracts. In the vast majority of cases, there are more purine tracts than would be expected from a random sequence, with an average of 3.5%, significantly larger than the expectation value. The fraction of the chromosomes containing pyr......, in eukaryotes there is an abundance of long stretches of purines or alternating purine/pyrimidine tracts, which cannot be explained in this way; these sequences are likely to play an important role in eukaryotic chromosome organisation....

  17. Anisotropic dewetting on stretched elastomeric substrates.

    Science.gov (United States)

    Qiao, L; He, L H

    2008-08-01

    We study the instability of a very thin liquid film resting on a uniformly stretched soft elastomeric substrate driven by van der Waals forces. A linear stability analysis shows that the critical fluctuation wavelength in the tensile direction is larger than those in the other directions. The magnitudes of the critical wavelengths are adjustable in the sense that they depend on the principal stretch of the substrate. For example, when the principal stretch of the substrate varies from 1.0 (unstretched) to 3.0, the range of the critical wavelength in the tensile direction increases by 7.0% while that normal to the tensile direction decreases by 8.7%. Therefore, the phenomenon may find potential applications in creating tunable topographically patterned surfaces with nano- to microscale features.

  18. Flow of nanofluid by nonlinear stretching velocity

    Science.gov (United States)

    Hayat, Tasawar; Rashid, Madiha; Alsaedi, Ahmed; Ahmad, Bashir

    2018-03-01

    Main objective in this article is to model and analyze the nanofluid flow induced by curved surface with nonlinear stretching velocity. Nanofluid comprises water and silver. Governing problem is solved by using homotopy analysis method (HAM). Induced magnetic field for low magnetic Reynolds number is not entertained. Development of convergent series solutions for velocity and skin friction coefficient is successfully made. Pressure in the boundary layer flow by curved stretching surface cannot be ignored. It is found that magnitude of power-law index parameter increases for pressure distibutions. Magnitude of radius of curvature reduces for pressure field while opposite trend can be observed for velocity.

  19. Lattice stretching bistability and dynamic heterogeneity

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Savin, A. V.; Zolotaryuk, A. V.

    2012-01-01

    A simple one-dimensional lattice model is suggested to describe the experimentally observed plateau in force-stretching diagrams for some macromolecules. This chain model involves the nearest-neighbor interaction of a Morse-like potential (required to have a saturation branch) and a harmonic second......-neighbor coupling. Under an external stretching applied to the chain ends, the intersite Morse-like potential results in the appearance of a double-well potential within each chain monomer, whereas the interaction between the second neighbors provides a homogeneous bistable (degenerate) ground state, at least...

  20. Stretching and folding mechanism in foams

    Energy Technology Data Exchange (ETDEWEB)

    Tufaile, Alberto [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)], E-mail: tufaile@usp.br; Pedrosa Biscaia Tufaile, Adriana [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)

    2008-10-13

    We have described the stretching and folding of foams in a vertical Hele-Shaw cell containing air and a surfactant solution, from a sequence of upside-down flips. Besides the fractal dimension of the foam, we have observed the logistic growth for the soap film length. The stretching and folding mechanism is present during the foam formation, and this mechanism is observed even after the foam has reached its respective maximum fractal dimension. Observing the motion of bubbles inside the foam, large bubbles present power spectrum associated with random walk motion in both directions, while the small bubbles are scattered like balls in a Galton board.

  1. Immediate effects of quantified hamstring stretching: hold-relax proprioceptive neuromuscular facilitation versus static stretching.

    Science.gov (United States)

    Puentedura, Emilio J; Huijbregts, Peter A; Celeste, Shelley; Edwards, Dale; In, Alastair; Landers, Merrill R; Fernandez-de-Las-Penas, Cesar

    2011-08-01

    To compare the immediate effects of a hold-relax proprioceptive neuromuscular facilitation stretching (HR-PNF) versus static stretch (SS) on hamstring flexibility in healthy, asymptomatic subjects. Thirty subjects (13 female; mean age 25.7 ± 3.0, range 22-37) without excessive hamstring muscle flexibility were randomly assigned to one of two stretch groups: HR-PNF or SS. The left leg was treated as a control and did not receive any intervention. The right leg was measured for ROM pre- and post-stretch interventions, with subjects receiving randomly assigned interventions one week apart. Data were analyzed with a 3 (intervention: HR-PNF, SS, control) × 2 (time: pre and post) factorial ANOVA with repeated measures and appropriate post-hoc analyses. A significant interaction was observed between intervention and time for hamstring extensibility, F(2,58) = 25.229, p < .0005. Main effect of intervention for the tested leg was not significant, p = .782 indicating that there was no difference between the two stretch conditions. However, main effect for time was significant (p < .0005), suggesting that hamstring extensibility (for both stretching conditions) after intervention was greater than before. No significant differences were found when comparing the effectiveness of HR-PNF and SS techniques. Both stretching methods resulted in significant immediate increases in hamstring length. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Realistic searches on stretched exponential networks

    Indian Academy of Sciences (India)

    Vol. 71, No. 2. — journal of. August 2008 physics pp. 313–317. Realistic searches on stretched exponential networks. PARONGAMA SEN. Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road,. Kolkata 700 009, India .... [4] S Milgram, Psychology Today 1, 60 (1967). J Travers and S Milgram, ...

  3. Filament stretching rheometry of polymer melts

    DEFF Research Database (Denmark)

    Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

    2005-01-01

    The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

  4. Cloud Network Helps Stretch IT Dollars

    Science.gov (United States)

    Collins, Hilton

    2012-01-01

    No matter how many car washes or bake sales schools host to raise money, adding funds to their coffers is a recurring problem. This perpetual financial difficulty makes expansive technology purchases or changes seem like a pipe dream for school CIOs and has education technologists searching for ways to stretch money. In 2005, state K-12 school…

  5. The stretch zone of automotive steel sheets

    Indian Academy of Sciences (India)

    on steel grade, on the rolling direction as well as on the loading rate. Stretch zones ... This interaction is demonstrated at a fracture surface as a bounded transition between initiatory crack (e.g., fatigue) and either ... The materials examined in this study are three grades of thin automotive steel sheets: XSG,. HR 45 and DP.

  6. Fractional behaviour at cyclic stretch-bending

    NARCIS (Netherlands)

    Emmens, W.C.; van den Boogaard, Antonius H.; Kazantzis, A.V.; de Hosson, J.Th.M.; Kolleck, R

    2010-01-01

    The fractional behaviour at cyclic stretch-bending has been studied by performing tensile tests at long specimens that are cyclically bent at the same time, on mild steel, dual-phase steel, stainless steel, aluminium and brass. Several types of fracture are observed, these are discussed, as are the

  7. EFFECTIVENESS OF PNF STRETCHING AND CYCLIC STRETCHING OF CALF TIGHTNESS ON COLLEGE GOING GIRLS

    Directory of Open Access Journals (Sweden)

    Ashlesha Sirari

    2015-06-01

    Full Text Available Background: Flexibility helps with injury prevention, the reduction of soreness following a workout, and a general sense of well-being. There are different stretching techniques and protocols for improvements in calf extensibility and flexibility. The purpose of the study was to investigate the effectiveness of two techniques i.e. CYCLIC and PNF stretching which improves calf flexibility. This study was done to find the effectiveness of calf Cyclic and PNF stretching technique to improve calf flexibility. Methods: 30 subjects with age group 21-22 years were randomly allocated to 2 groups equally. Group 1(n=15 were given CYCLIC and group 2(n=15 were given PNF stretching technique. Plantar flexion was used to measure the calf tightness which was done before and after the treatment. Treatment was given for 7 days and on the 7th day the calf tightness was again measured. Results: The mean difference of the CYCLIC is 4.6 and mean difference of PNF is 4.7 which indicate that CYCLIC and PNF both are effective to improve calf flexibility but PNF is more effective than CYCLIC to improve calf flexibility. Conclusion: The neurophysiological basis of PNF, stating that the excitatory efficient of the neuromuscular spindle or the inhibitory afferent of the Golgi tendon organ (GTO or both are responsible for the effects. During PNF stretch and isometric contraction of stretched agonists for extended period may cause activation of its neuromuscular spindle. The increase in tension created during the isometric contraction of the pre – lengthened agonist contracts concentrically. Both the fascia & the spindle of the agonist adjust to the nearly lengthened position. These impulses travel via causing post synaptic inhibition of the motor neuron to agonist increasing the tension from the GTO. These impulses can override the impulses coming from the neuromuscular spindles arousing the muscle to reflexly resist to the change in length, thus helping in lengthening

  8. Passive Stretch Versus Active Stretch on Intervertebral Movement in Non - Specific Neck Pain

    International Nuclear Information System (INIS)

    Abd El - Aziz, A.H.; Amin, D.I.; Moustafa, I.

    2016-01-01

    Neck pain is one of the most common and painful musculoskeletal conditions. Point prevalence ranges from 6% to 22% and up to 38% of the elderly population, while lifetime prevalence ranges from 14,2% to 71%. Up till now no randomized study showed the effect between controversy of active and passive stretch on intervertebral movement. The purpose: the current study was to investigate the effect of the passive and active stretch on intervertebral movement in non - specific neck pain. Material and methods: Forty five subjects from both sexes with age range between 18 and 30 years and assigned in three groups, group I (15) received active stretch, ultrasound and TENS. Group II (15) received passive stretch, ultrasound and TENS. Group III (15) received ultrasound and TENS. The radiological assessment was used to measure rotational and translational movement of intervertebral movement before and after treatment. Results: MANOVA test was used for radiological assessment before and after treatment there was significant increase in intervertebral movement in group I as p value =0.0001. Conclusion: active stretch had a effect in increasing the intervertebral movement compared to the passive stretch

  9. More light on the 2ν{sub 5} Raman overtone of SF{sub 6}: Can a weak anisotropic spectrum be due to a strong transition anisotropy?

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, D.; Rachet, F.; Chrysos, M., E-mail: michel.chrysos@univ-angers.fr [LUNAM Université, Université d’Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers (France)

    2014-01-21

    Long known as a fully polarized band with a near vanishing depolarization ratio [η{sub s} = 0.05, W. Holzer and R. Ouillon, Chem. Phys. Lett. 24, 589 (1974)], the 2ν{sub 5} Raman overtone of SF{sub 6} has so far been considered as of having a prohibitively weak anisotropic spectrum [D. P. Shelton and L. Ulivi, J. Chem. Phys. 89, 149 (1988)]. Here, we report the first anisotropic spectrum of this overtone, at room temperature and for 13 gas densities ranging between 2 and 27 amagat. This spectrum is 10 times broader and 50 times weaker than the isotropic counterpart of the overtone [D. Kremer, F. Rachet, and M. Chrysos, J. Chem. Phys. 138, 174308 (2013)] and its profile much more sensitive to pressure effects than the profile of the isotropic spectrum. From our measurements an accurate value for the anisotropy matrix-element |〈000020|Δα|000000〉| was derived and this value was found to be comparable to that of the mean-polarizability ((000020), α{sup ¯} (000000)). Among other conclusions our study offers compelling evidence that, in Raman spectroscopy, highly polarized bands or tiny depolarization ratios are not necessarily incompatible with large polarizability anisotropy transition matrix-elements. Our findings and the way to analyze them suggest that new strategies should be developed on the basis of the complementarity inherent in independent incoherent Raman experiments that run with two different incident-beam polarizations, and on concerted efforts to ab initio calculate accurate data for first and second polarizability derivatives. Values for these derivatives are still rarities in the literature of SF{sub 6}.

  10. How to Stretch Your Ankle After a Sprain

    Science.gov (United States)

    ... Ankle After A Sprain How to Stretch Your Ankle After A Sprain Page Content You should perform the following stretches ... Consider these home exercises when recuperating from an ankle sprain. Perform them twice per day. While seated, bring ...

  11. Vibrational spectra of opal-based photonic crystals

    International Nuclear Information System (INIS)

    Dovbeshko, G; Fesenko, O; Boyko, V; Romanyuk, V; Moiseyenko, V; Gorelik, V; Dolgov, L; Kiisk, V; Sildos, I

    2012-01-01

    Synthetic silica opals were investigated by infrared and Raman spectroscopies. Vibrational modes associated with molecular groups of opal globules and admixtures were detected. Similarities in Raman and infrared spectra of synthetic opal with reference fused and α-quartz indicate the presence of amorphous phase in opal globules. Also some spectral bands designate on modified optical stretching vibrations at 1000-1200 cm −1 and bigger amount of Si-H defects in photonic crystal.

  12. Transparent conducting film: Effect of mechanical stretching to ...

    Indian Academy of Sciences (India)

    Administrator

    posite was fixed to a tabletop clamp and unidirectionally stretched after cutting the paper support at two opposite sides. To hold the film under the stretched condition, both edges of stretched CNT-mat/transparent-film composite was then adhered to a PMMA substrate by epoxy glue and both the sheet resistance and the ...

  13. Effects of dynamic stretches on Isokinetic hamstring and Quadriceps ...

    African Journals Online (AJOL)

    In conclusion, dynamic stretches have positive effects on muscle strength, H/Q ratios and ROM. Therefore, dynamic stretches may increase performance and reduce the risk of injury to athletes. Keywords: Quadriceps; Hamstrings; Muscles Isokinetic; Dynamic stretches. South African Journal for Research in Sport, Physical ...

  14. Stretched cell cycle model for proliferating lymphocytes

    Science.gov (United States)

    Dowling, Mark R.; Kan, Andrey; Heinzel, Susanne; Zhou, Jie H. S.; Marchingo, Julia M.; Wellard, Cameron J.; Markham, John F.; Hodgkin, Philip D.

    2014-01-01

    Stochastic variation in cell cycle time is a consistent feature of otherwise similar cells within a growing population. Classic studies concluded that the bulk of the variation occurs in the G1 phase, and many mathematical models assume a constant time for traversing the S/G2/M phases. By direct observation of transgenic fluorescent fusion proteins that report the onset of S phase, we establish that dividing B and T lymphocytes spend a near-fixed proportion of total division time in S/G2/M phases, and this proportion is correlated between sibling cells. This result is inconsistent with models that assume independent times for consecutive phases. Instead, we propose a stretching model for dividing lymphocytes where all parts of the cell cycle are proportional to total division time. Data fitting based on a stretched cell cycle model can significantly improve estimates of cell cycle parameters drawn from DNA labeling data used to monitor immune cell dynamics. PMID:24733943

  15. String Stretching, Frequency Modulation, and Banjo Clang

    OpenAIRE

    Politzer, David

    2014-01-01

    The banjo’s floating bridge, string break angle, and flexible drumhead all contribute to substantial audio range frequency modulation. From the world of electronic music synthesis, it is known that modulating higher frequency sounds with lower acoustic frequencies leads to metallic and bell-like tone. The mechanics of the banjo does just that quite naturally, modulating fundamentals and harmonics with the motion of the bridge. In technical terms, with a floating bridge, string stretching is f...

  16. The stretch zone of automotive steel sheets

    Indian Academy of Sciences (India)

    The stretch zone of automotive steel sheets. L' AMBRIŠKO1,∗ and L PEŠEK2. 1Institute of Structural Engineering, Faculty of Civil Engineering,. Technical University of Košice, Vysokoškolská 4, 042 00 Košice, Slovak Republic. 2Department of Materials Science, Faculty of Metallurgy,. Technical University of Košice, Letná 9, ...

  17. Spontaneous bending of pre-stretched bilayers.

    Science.gov (United States)

    DeSimone, Antonio

    2018-01-01

    We discuss spontaneously bent configurations of pre-stretched bilayer sheets that can be obtained by tuning the pre-stretches in the two layers. The two-dimensional nonlinear plate model we use for this purpose is an adaptation of the one recently obtained for thin sheets of nematic elastomers, by means of a rigorous dimensional reduction argument based on the theory of Gamma-convergence (Agostiniani and DeSimone in Meccanica. doi:10.1007/s11012-017-0630-4, 2017, Math Mech Solids. doi:10.1177/1081286517699991, arXiv:1509.07003, 2017). We argue that pre-stretched bilayer sheets provide us with an interesting model system to study shape programming and morphing of surfaces in other, more complex systems, where spontaneous deformations are induced by swelling due to the absorption of a liquid, phase transformations, thermal or electro-magnetic stimuli. These include bio-mimetic structures inspired by biological systems from both the plant and the animal kingdoms.

  18. Dynamics and structure of stretched flames

    Energy Technology Data Exchange (ETDEWEB)

    Law, C.K. [Princeton Univ., NJ (United States)

    1993-12-01

    This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

  19. Stretch Moduli of Ribonucleotide Embedded Short DNAs

    Science.gov (United States)

    Chiu, Hsiang-Chih; Koh, Kyung Duk; Riedo, Elisa; Storici, Francesca

    2013-03-01

    Understanding the mechanical properties of DNA is essential to comprehending the dynamics of many cellular functions. DNA deformations are involved in many mechanisms when genetic information needs to be stored and used. In addition, recent studies have found that Ribonucleotides (rNMPs) are among the most common non-standard nucleotides present in DNA. The presences of rNMPs in DNA might cause mutation, fragility or genotoxicity of chromosome but how they influence the structure and mechanical properties of DNA remains unclear. By means of Atomic Force Microscopy (AFM) based single molecule spectroscopy, we measure the stretch moduli of double stranded DNAs (dsDNA) with 30 base pairs and 5 equally embedded rNMPs. The dsDNAs are anchored on gold substrate via thiol chemistry, while the AFM tip is used to pick up and stretch the dsDNA from its free end through biotin-streptavidin bonding. Our preliminary results indicate that the inclusion of rNMPs in dsDNA might significantly change its stretch modulus, which might be important in some biological processes.

  20. Explaining the Railsback stretch in terms of the inharmonicity of piano tones and sensory dissonance.

    Science.gov (United States)

    Giordano, N

    2015-10-01

    The perceptual results of Plomp and Levelt [J. Acoust. Soc. Am. 38, 548-560 (1965)] for the sensory dissonance of a pair of pure tones are used to estimate the dissonance of pairs of piano tones. By using the spectra of tones measured for a real piano, the effect of the inharmonicity of the tones is included. This leads to a prediction for how the tuning of this piano should deviate from an ideal equal tempered scale so as to give the smallest sensory dissonance and hence give the most pleasing tuning. The results agree with the well known "Railsback stretch," the average tuning curve produced by skilled piano technicians. The authors' analysis thus gives a quantitative explanation of the magnitude of the Railsback stretch in terms of the human perception of dissonance.

  1. Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

    Science.gov (United States)

    Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

  2. Spectra of Graphs

    NARCIS (Netherlands)

    Brouwer, A.E.; Haemers, W.H.

    2012-01-01

    This book gives an elementary treatment of the basic material about graph spectra, both for ordinary, and Laplace and Seidel spectra. The text progresses systematically, by covering standard topics before presenting some new material on trees, strongly regular graphs, two-graphs, association

  3. Spectra of alkali atoms

    International Nuclear Information System (INIS)

    Santoso, Budi; Arumbinang, Haryono.

    1981-01-01

    Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

  4. Linear and Non-Linear Thermal Lens Signal of the Fifth C-H Vibrational Overtone of Naphthalene in Liquid Solutions of Hexane

    Science.gov (United States)

    Manzanares, Carlos; Diaz, Marlon; Barton, Ann; Nyaupane, Parashu R.

    2017-06-01

    The thermal lens technique is applied to vibrational overtone spectroscopy of solutions of naphthalene in n-hexane. The pump and probe thermal lens technique is found to be very sensitive for detecting samples of low composition (ppm) in transparent solvents. In this experiment two different probe lasers: one at 488 nm and another 568 nm were used. The C-H fifth vibrational overtone spectrum of benzene is detected at room temperature for different concentrations. A plot of normalized integrated intensity as a function of concentration of naphthalene in solution reveals a non-linear behavior at low concentrations when using the 488 nm probe and a linear behavior over the entire range of concentrations when using the 568 nm probe. The non-linearity cannot be explained assuming solvent enhancement at low concentrations. A two color absorption model that includes the simultaneous absorption of the pump and probe lasers could explain the enhanced magnitude and the non-linear behavior of the thermal lens signal. Other possible mechanisms will also be discussed.

  5. Linear and Nonlinear Thermal Lens Signal of the (Δν = 6) C-H Vibrational Overtone of Naphthalene in Liquid Solutions of n-Hexane.

    Science.gov (United States)

    Nyaupane, Parashu R; Diaz, Marlon; Barton, Ann; Manzanares, Carlos E

    2018-01-01

    The thermal lens technique is applied to vibrational overtone spectroscopy of solutions of naphthalene (C 10 H 8 ) in liquid hexane. The C-H fifth vibrational (Δν = 6) overtone spectrum of C 10 H 8 is detected at room temperature for mole fractions from 0.08 to 19 × 10 -6 using n-C 6 H 14 as solvent. By detecting the absorption band in a 19 ppm (parts per million) solution, the peak absorption of the signal is approximately (2.2 ± 0.3) × 10 -7  cm -1 . A plot of normalized integrated intensity as a function of the mole fraction of naphthalene in solution reveals a dependence of the magnitude of the signal with the probe laser wavelength. If the wavelength of the probe laser is 568 nm, the thermal lens signal (TLS) is linear as a function of the mole fraction of the solution. When the wavelength of the probe laser is 488 nm, the TLS is nonlinear as a function of the concentration. Three different models of nonlinear absorption are discussed. A two-color absorption model that includes the simultaneous absorption of the pump and probe lasers could explain the enhanced magnitude and the nonlinear behavior of the TLS for solutions of mole fraction < 0.1%.

  6. CARBONYL STRETCHING FREQUENCY-CHARACTERISTICS FOR THE STRONGLY HYDROPHOBIC SOLUTE, N-CYCLOHEXYL-2-PYRROLIDONE IN BINARY AQUEOUS MIXTURES AT 298.15-K - EVIDENCE FOR A 2-DOMAIN MODEL FOR 2-BUTOXYETHANOL WATER MIXTURES

    NARCIS (Netherlands)

    Engberts, Jan B F N; PERJESSY, A; Blandamer, Michael J; EATON, G

    1992-01-01

    Infrared spectra are reported in the C=O stretching region for N-cyclohexyl-2-pyrrolidone (NCP) in D2O as a function of the mole fraction of added cosolvents. As the solvent composition is changed by adding methanol, ethanol and 2-methylpropan-2-ol, the spectra reveal the presence of two types of

  7. The Relevance of Stretch Intensity and Position: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Nikos eApostolopoulos

    2015-08-01

    Full Text Available Stretching exercises to increase the range of motion (ROM of joints have been used by sports coaches and medical professionals for improving performance and rehabilitation. The ability of connective and muscular tissues to change their architecture in response to stretching is important for their proper function, repair and performance. Given the dearth of relevant data in the literature, this review examined two key elements of stretching: stretch intensity and stretch position; and their significance to ROM, delayed onset muscle soreness (DOMS, and inflammation in different populations. A search of three databases, Pub-Med, Google Scholar, and Cochrane Reviews, identified 152 articles, which were subsequently categorized into four groups; athletes (n = 24, clinical (n = 29, elderly (n = 12, and general population (n = 87. The use of different populations facilitated a wider examination of the stretching components and their effects. All 152 articles incorporated information regarding duration, frequency and stretch position, whereas only 79 referred to the intensity of stretching and 22 of these 79 studies were deemed high quality. It appears that the intensity of stretching is relatively under-researched, and the importance of body position and its influence on stretch intensity, is largely unknown. In conclusion, this review has highlighted areas for future research, including stretch intensity and position and their effect on musculo-tendinous tissue, in relation to the sensation of pain, delayed onset muscle soreness, inflammation, as well as muscle health and performance

  8. Hamstring Stiffness Returns More Rapidly After Static Stretching Than Range of Motion, Stretch Tolerance, and Isometric Peak Torque.

    Science.gov (United States)

    Hatano, Genki; Suzuki, Shigeyuki; Matsuo, Shingo; Kataura, Satoshi; Yokoi, Kazuaki; Fukaya, Taizan; Fujiwara, Mitsuhiro; Asai, Yuji; Iwata, Masahiro

    2017-12-18

    Hamstring injuries are common, and lack of hamstring flexibility may predispose to injury. Static stretching increases range of motion (ROM) but also results in reduced muscle strength after stretching. The effects of stretching on the hamstring muscles and the duration of these effects remain unclear. To determine the effects of static stretching on the hamstrings and the duration of these effects. Randomized crossover study. University laboratory. Twenty-four healthy volunteers. We measured the torque-angle relationship (ROM, passive torque (PT) at the onset of pain, and passive stiffness) and isometric muscle force using an isokinetic dynamometer. After a 60-minute rest, the ROM of the dynamometer was set at maximum tolerable intensity; this position was maintained for 300 seconds while static passive torque (SPT) was measured continuously. We remeasured the torque-angle relationship and isometric muscle force after rest periods of 10, 20, and 30 minutes. Change in SPT during stretching; changes in ROM, PT at the onset of pain, passive stiffness, and isometric muscle force before stretching compared with 10, 20, and 30 minutes after stretching. SPT decreased significantly during stretching. Passive stiffness decreased significantly 10 and 20 minutes after stretching, but there was no significant pre- vs. post-stretching difference after 30 minutes. PT at the onset of pain and ROM increased significantly after stretching at all rest intervals, while isometric muscle force decreased significantly after all rest intervals. The effect of static stretching on passive stiffness of the hamstrings was not maintained as long as the changes in ROM, stretch tolerance, and isometric muscle force. Therefore, frequent stretching is necessary to improve the viscoelasticity of the muscle-tendon unit. Muscle force was decreased for 30 minutes after stretching; this should be considered prior to activities requiring maximal muscle strength.

  9. SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

    OpenAIRE

    Del P. Wong; Anis Chaouachi; Patrick W.C. Lau; David G. Behm

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performe...

  10. The Rovibronic Spectra of the Cyclopentadienyl Radical

    Science.gov (United States)

    Sharma, Ketan; Miller, Terry A.; Stanton, John F.; Nesbitt, David

    2017-06-01

    Cyclopentadienyl (Cp) radical has been subject to numerous studies for the greater part of half a century. Experimental work has involved photo-electron spectroscopy, laser induced fluorescence excitation and emission, infrared absorption spectroscopy, and recently rotationally resolved spectra in the CH stretch region taken at JILA. Even more theoretical works appear in the literature, but substantial advances in computation have occurred since their completion. Cp's highly symmetric (D_{5h}) structure and doubly degenerate electronic ground (˜{X}^2E_1^{''}), which is subject to linear Jahn-Teller distortion, have been a great motivation for work on it. We have commenced new computational work to obtain a broad understanding of the electronic, vibrational, and rotational, i.e. rovibronic, structure of the Cp radical as revealed by its spectra, with particular emphasis on the new infrared spectra. The goal is to guide experiments and their analyses and reconcile results from spectroscopy and quantum chemistry calculations. T. Ichino, et al. J. Chem. Phys. 129, 084310 (2008) L. Yu, S. C. Foster, J. M. Williamson, M. C. Heaven and T. A. Miller J. Phys. Chem. 92, 4263 (1988) B. E. Applegate, A. J. Bezant and T. A. Miller J. Chem. Phys 114, 4869 (2001) D. Leicht, M. Kaufmann, G. Schwaab, and M. Havenith J. Chem. Phys. 145, 7 (2016), 074304.

  11. Efficacy of static stretching and proprioceptive neuromuscular facilitation stretch on hamstrings length after a single session.

    Science.gov (United States)

    O'Hora, John; Cartwright, Abigail; Wade, Clive D; Hough, Alan D; Shum, Gary L K

    2011-06-01

    A number of studies have investigated the efficacy of several repetitions of proprioceptive neuromuscular facilitation stretching (PNF) and static stretching (SS). However, there is limited research comparing the effects of a single bout of these stretching maneuvers. The aim of this study was to compare the effectiveness of a single bout of a therapist-applied 30-second SS vs. a single bout of therapist-applied 6-second hamstring (agonist) contract PNF. Forty-five healthy subjects between the ages of 21 and 35 were randomly allocated to 1 of the 2 stretching groups or a control group, in which no stretching was received. The flexibility of the hamstring was determined by a range of passive knee extension, measured using a universal goniometer, with the subject in the supine position and the hip at 90° flexion, before and after intervention. A significant increase in knee extension was found for both intervention groups after a single stretch (SS group = 7.53°, p < 0.01 and PNF group = 11.80°, p < 0.01). Both interventions resulted in a significantly greater increase in knee extension when compared to the control group (p < 0.01). The PNF group demonstrated significantly greater gains in knee extension compared to the SS group (mean difference 4.27°, p < 0.01). It can be concluded that a therapist applied SS or PNF results in a significant increase in hamstring flexibility. A hamstring (agonist) contract PNF is more effective than an SS in a single stretching session. These findings are important to physiotherapists or trainers working in clinical and sporting environments. Where in the past therapists may have spent time conducting multiple repetitions of a PNF and an SS, a single bout of either technique may be considered just as effective. A key component of the study methodology was the exclusion of a warm-up period before stretching. Therefore, the findings of efficacy of a single PNF are of particular relevance in sporting environments and busy clinical

  12. SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

    Directory of Open Access Journals (Sweden)

    Del P. Wong

    2011-06-01

    Full Text Available This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA and change of direction (COD. Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s. Three dynamic stretching exercises of 30 s duration were then performed (90 s total. Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p < 0.001. However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (< 90 s static stretching may not have provided sufficient stimulus to elicit performance impairments

  13. To Stretch and Search for Better Ways

    Science.gov (United States)

    Moore, John W.

    2000-06-01

    There's a lot to do to get each issue of this Journal ready for publication, and there's a lot that can go awry during that process. We the editorial staff do our utmost to make certain that each issue is the best it can possibly be, but, of necessity, a lot of our effort is focused on solving problems, correcting errors, and avoiding pitfalls. It is not surprising that we sometimes lose sight of the bigger picture--all of the things that came out as well as or better than we hoped they would. Therefore it gives us great pleasure when a reader applauds (and thereby rewards) our efforts. One such communication inspired this editorial. I have appreciated the extra effort put forward by the staff to make the Journal really come alive. The high quality of the Journal serves as an incentive to chemical educators to stretch and search for better ways to inspire our students. I fervently hope that we do encourage you "to stretch and search for better ways", not only to inspire students but in everything you do. Stretching and searching for better ways is what life, science, chemistry, and teaching are all about, and it is a wonderfully stimulating and exciting way to approach anything and everything. Sometimes, though, one's ability to stretch is akin to that of a rubber band exposed too long to sunlight. Change becomes a threat or a burden instead of an opportunity. This often happens in one area but not others, as in the case of someone doing original research but whose lecture notes are yellow with age, or someone who experiments with new teaching approaches but neglects the latest chemical discoveries. Whatever its manifestation, failure to stretch and search for better ways is a great loss, both for the individual directly involved and for others. Fortunately there are many who continually stretch and search, often in conjunction with JCE. For example, some time ago the Chair of the Board of Publication, Jerry Bell, challenged Journal readers to become Journal

  14. Optical stretching on chip with acoustophoretic prefocusing

    DEFF Research Database (Denmark)

    Khoury Arvelo, Maria; Laub Busk, L.; Bruus, Henrik

    2012-01-01

    prefocusing. This focusing mechanism aims for target particles to always ow in the correct height relative to the optical stretcher, and is induced by a piezo-electric ultrasound transducer attached underneath the chip and driven at a frequency leading to a vertical standing ultrasound wave...... in the microchannel. Trapping and manipulation is demonstrated for dielectric beads. In addition, we show trapping, manipulation and stretching of red blood cells and vesicles, whereby we extract the elastic properties of these objects. Our design points towards the construction of a low-cost, high-throughput lab-on-a-chip...

  15. Viscous flows stretching and shrinking of surfaces

    CERN Document Server

    Mehmood, Ahmer

    2017-01-01

    This authored monograph provides a detailed discussion of the boundary layer flow due to a moving plate. The topical focus lies on the 2- and 3-dimensional case, considering axially symmetric and unsteady flows. The author derives a criterion for the self-similar and non-similar flow, and the turbulent flow due to a stretching or shrinking sheet is also discussed. The target audience primarily comprises research experts in the field of boundary layer flow, but the book will also be beneficial for graduate students.

  16. SAWYER ASTEROID SPECTRA

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains 94 optical asteroid spectra obtained by Scott Sawyer as part of his Ph.D. dissertation at the University of Texas at Austin. Observational...

  17. Twist-stretch profiles of DNA chains

    Science.gov (United States)

    Zoli, Marco

    2017-06-01

    Helical molecules change their twist number under the effect of a mechanical load. We study the twist-stretch relation for a set of short DNA molecules modeled by a mesoscopic Hamiltonian. Finite temperature path integral techniques are applied to generate a large ensemble of possible configurations for the base pairs of the sequence. The model also accounts for the bending and twisting fluctuations between adjacent base pairs along the molecules stack. Simulating a broad range of twisting conformation, we compute the helix structural parameters by averaging over the ensemble of base pairs configurations. The method selects, for any applied force, the average twist angle which minimizes the molecule’s free energy. It is found that the chains generally over-twist under an applied stretching and the over-twisting is physically associated to the contraction of the average helix diameter, i.e. to the damping of the base pair fluctuations. Instead, assuming that the maximum amplitude of the bending fluctuations may decrease against the external load, the DNA molecule first over-twists for weak applied forces and then untwists above a characteristic force value. Our results are discussed in relation to available experimental information albeit for kilo-base long molecules.

  18. Effects of stretching the scalene muscles on slow vital capacity.

    Science.gov (United States)

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-06-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study's methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 times at per each portion of scalene muscles: the anterior, middle, and posterior parts. [Results] Expiratory vital capacity (EVC) and tidal volume (Vt) noticeably increased after stretching. However, there were no changes in any of the SVC items in the control group. [Conclusion] This study demonstrated that stretching of the scalene muscles can effectively improve SVC. In particular, we confirmed that stretching of the scalene muscles was effective in increasing EVC and Vt, which are items of SVC.

  19. Mechanical stretch influence on lifetime of dielectric elastomer films

    Science.gov (United States)

    Iannarelli, A.; Niasar, M. Ghaffarian

    2017-04-01

    Film pre-stretching is a widely adopted solution to improve dielectric strength of the DEA systems. However, to date, long term reliability of this solution has not been investigated. In this work it is explored how the dielectric elastomer lifetime is affected by film pre-stretching. The dielectric loss of soft polydimethylsiloxane (PDMS) films is studied for different stretch ratios by measuring tanδ. Additionally, time-to-breakdown was measured at DC electric stress for different stretch ratios. For this purpose, accelerated life test (ALT) were performed. The results obtained are compared with non-pre-stretched samples. This study suggests that no additional dielectric losses are caused by film stretching up to 80% of original dimensions.

  20. Proprioceptive neuromuscular facilitation stretching : mechanisms and clinical implications.

    Science.gov (United States)

    Sharman, Melanie J; Cresswell, Andrew G; Riek, Stephan

    2006-01-01

    Proprioceptive neuromuscular facilitation (PNF) stretching techniques are commonly used in the athletic and clinical environments to enhance both active and passive range of motion (ROM) with a view to optimising motor performance and rehabilitation. PNF stretching is positioned in the literature as the most effective stretching technique when the aim is to increase ROM, particularly in respect to short-term changes in ROM. With due consideration of the heterogeneity across the applied PNF stretching research, a summary of the findings suggests that an 'active' PNF stretching technique achieves the greatest gains in ROM, e.g. utilising a shortening contraction of the opposing muscle to place the target muscle on stretch, followed by a static contraction of the target muscle. The inclusion of a shortening contraction of the opposing muscle appears to have the greatest impact on enhancing ROM. When including a static contraction of the target muscle, this needs to be held for approximately 3 seconds at no more than 20% of a maximum voluntary contraction. The greatest changes in ROM generally occur after the first repetition and in order to achieve more lasting changes in ROM, PNF stretching needs to be performed once or twice per week. The superior changes in ROM that PNF stretching often produces compared with other stretching techniques has traditionally been attributed to autogenic and/or reciprocal inhibition, although the literature does not support this hypothesis. Instead, and in the absence of a biomechanical explanation, the contemporary view proposes that PNF stretching influences the point at which stretch is perceived or tolerated. The mechanism(s) underpinning the change in stretch perception or tolerance are not known, although pain modulation has been suggested.

  1. The effect of stretching thiyl- and ethynyl-Au molecular junctions

    International Nuclear Information System (INIS)

    Hoft, R C; Ford, M J; GarcIa-Suarez, V M; Lambert, C J; Cortie, M B

    2008-01-01

    We perform density functional theory (DFT) calculations of the stretching of Au(111)-X-Au(111) molecular junctions where X is either a thiyl or ethynyl biradical. The equilibrium geometries for the radicals adsorbing on the surface are first calculated and the radicals then placed in the junction geometry. The unit cell is stepwise increased in length and the geometry relaxed at each step. When stretching the ethynyl junction, a single gold atom is detached from the rest of the surface and the gold-carbon bond does not break. In contrast, the gold-sulfur bond in the thiyl junction breaks without detaching any gold atoms. This behaviour can be attributed to the enhanced strength of the Au-C interaction over the Au-S interaction. In both junctions the conductance calculated using the non-equilibrium Green's function formalism (NEGF) decreases as the junction is stretched. After breakage of the Au-S bond, the thiyl radical contains an unpaired electron on the sulfur atom and the system is in a spin doublet state. Transmission spectra were calculated for the spin-unpolarized case only; evaluation of the spin-polarized density of states suggests that an enhanced conductance for electrons of one spin type may be observed after the Au-S bond is broken

  2. Origin of the anomalous Fe-CO stretching mode in the CO complex of Ascaris hemoglobin.

    Science.gov (United States)

    Das, T K; Friedman, J M; Kloek, A P; Goldberg, D E; Rousseau, D L

    2000-02-01

    We report an unusually high frequency (543 cm(-)(1)) for an Fe-CO stretching mode in the CO complex of Ascaris suum hemoglobin as compared to vertebrate hemoglobins in which the frequency of the Fe-CO mode is much lower. A second Fe-CO stretching mode in Ascaris hemoglobin is observed at 515 cm(-1). We propose that these two Fe-CO stretching modes arise from two protein conformers corresponding to interactions of the heme-bound CO with the B10-tyrosine or the E7-glutamine residues. This postulate is supported by spectra from the B10-Tyr --> Phe mutant in which the 543 cm(-1) line is absent. Thus, a strong polar interaction, such as hydrogen bonding, of the CO with the distal B10 tyrosine residue is the dominant factor that causes this anomalously high frequency. Strong hydrogen bonding between O(2) and distal residues in the oxy complex of Ascaris hemoglobin has been shown to result in a rigid structure, rendering an extremely low oxygen off rate [Gibson, Q. H., and Smith, M. H. (1965) Proc. R. Soc. London B 163, 206-214]. In contrast, the CO off rate in Ascaris hemoglobin is very similar to that in sperm whale myoglobin. The high CO off rate relative to that of O(2) in Ascaris hemoglobin is attributed to a rapid equilibrium between the two conformations of the protein in the CO adduct, with the off rate being determined by the conformer with the higher rate.

  3. Study of high-overtone bulk acoustic resonators based on the Me1/AlN/Me2/(100) diamond piezoelectric layered structure

    Science.gov (United States)

    Sorokin, B. P.; Kvashnin, G. M.; Telichko, A. V.; Gordeev, G. I.; Burkov, S. I.; Blank, V. D.

    2015-07-01

    The Me1/AlN/Me2/(100) diamond structure has been theoretically analyzed and experimentally investigated in the range 0.5-10 GHz using high-overtone bulk acoustic resonators with different electrodes topologies based on the Al/AlN/Mo/(100) diamond structure. The maximum quality parameter Q × f ≈ 1014 Hz was obtained at f = 9.5 GHz. The layered structure has been analyzed using the developed HBAR software v. 2.3. It is demonstrated that the features in the frequency dependences of the parameters of such resonators are related to the behavior of a loaded thin-film piezoelectric transducer. The calculation results are in good agreement with the experiment. The frequency dependences of the equivalent parameters of the resonators have been calculated. It is shown that the synthetic type IIa diamond single crystal in combination with aluminum nitride is promising for implementation of high-Q acoustoelectronic microwave devices.

  4. Meyer-Overton reforged: The origins of alcohol and anesthetic potency in membranes as determined by a new NMR partitioning probe, benzyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Janes, N.; Ma, L.; Hsu, J.W.; Rubin, E.; Taraschi, T.F. (Thomas Jefferson Univ., Philadelphia, PA (United States))

    1992-01-01

    The Meyer-Overton hypothesis--that anesthesia arises from the nonspecific action of solutes on membrane lipids--is reformulated using colligative thermodynamics. Configurational entropy, the randomness imparted by the solute through the partitioning process, is implicated as the energetic driving force that pertubs cooperative membrane equilibria. A proton NMR partitioning approach based on the anesthetic benzyl alcohol is developed to assess the reformulation. Ring resonances from the partitioned drug are shielded by 0.2 ppm and resolved from the free, aqueous drug. Free alcohol is quantitated in dilute lipid dispersions using an acetate internal standard. Cooperative equilibria in model dipalmitoyl lecithin membranes are examined with changes in temperature and alcohol concentration. The L[sub [beta][prime

  5. Correlation between structure and conductivity in stretched Nafion

    Science.gov (United States)

    Allahyarov, Elshad; Taylor, Philip

    2008-03-01

    We have used coarse-grained simulation methods to investigate the effect of stretching-induced structure orientation on the proton conductivity of Nafion-like polyelectrolyte membranes. Recent experimental data on the morphology of ionomers describe Nafion as an aggregation of polymeric backbone chains forming elongated objects embedded in a continuous ionic medium. Uniaxial stretching of a recast Nafion film causes a preferential orientation of these objects in the direction of stretching. Our simulations of humid Nafion show that this has a strong effect on the proton conductivity, which is enhanced along the stretching direction, while the conductivity perpendicular to the stretched polymer backbone is strongly reduced. Stretching also causes the perfluorinated side chains to orient perpendicular to the stretching axis. The sulphonate multiplets shrink in diameter as the stretching is increased and show a spatially periodic ordering in their distribution. This in turn affects the distribution of contained water at low water contents. The water forms a continuous network with narrow bridges between small water clusters absorbed in head-group multiplets. We find the morphological changes in the stretched Nafion to be retained upon removal of the uniaxial stress.

  6. Solar Energetic Particle Spectra

    Science.gov (United States)

    Ryan, J. M.; Boezio, M.; Bravar, U.; Bruno, A.; Christian, E. R.; de Nolfo, G. A.; Martucci, M.; Mergè, M.; Munini, R.; Ricci, M.; Sparvoli, R.; Stochaj, S.

    2017-12-01

    We report updated event-integrated spectra from several SEP events measured with PAMELA. The measurements were made from 2006 to 2014 in the energy range starting at 80 MeV and extending well above the neutron monitor threshold. The PAMELA instrument is in a high inclination, low Earth orbit and has access to SEPs when at high latitudes. Spectra have been assembled from these high-latitude measurements. The field of view of PAMELA is small and during the high-latitude passes it scans a wide range of asymptotic directions as the spacecraft orbits. Correcting for data gaps, solid angle effects and improved background corrections, we have compiled event-integrated intensity spectra for twenty-eight SEP events. Where statistics permit, the spectra exhibit power law shapes in energy with a high-energy exponential roll over. The events analyzed include two genuine ground level enhancements (GLE). In those cases the roll-over energy lies above the neutron monitor threshold ( 1 GV) while the others are lower. We see no qualitative difference between the spectra of GLE vs. non-GLE events, i.e., all roll over in an exponential fashion with rapidly decreasing intensity at high energies.

  7. Effects of contract-relax vs static stretching on stretch-induced strength loss and length-tension relationship

    DEFF Research Database (Denmark)

    Balle, S S; Magnusson, S P; McHugh, M P

    2015-01-01

    The purpose of this study was to determine the acute effects of contract-relax stretching (CRS) vs static stretching (SS) on strength loss and the length-tension relationship. We hypothesized that there would be a greater muscle length-specific effect of CRS vs SS. Isometric hamstring strength...... loss compared with SS. These results support the use of SS for stretching the hamstrings....

  8. EFFECTIVENESS OF PNF STRETCHING VERSUS STATIC STRETCHING ON PAIN AND HAMSTRING FLEXIBILITY FOLLOWING MOIST HEAT IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

    Directory of Open Access Journals (Sweden)

    Meena .V

    2016-10-01

    Full Text Available Background: Osteoarthritis (OA is a degenerative joint disease and one of the major public health problem that causesfunctional impairment and reduced quality of life. To compare the effectiveness of PNF Hold relax stretching versus Static stretching on pain and flexibility of hamstring following moist heat in individuals with knee osteoarthritis. Hamstring tightness is the major problem in knee osteoarthritis individuals. Therefore the need of study is comparing the effectiveness of PNF Hold relax stretching versus static stretching on pain and flexibility of hamstrings following moist heat in knee osteoarthritis participants. Determining the effects of PNF Hold relax stretching versus Static stretching along with moist heat on pain and hamstring flexibility by VAS and Active knee extension range of motion in knee osteoarthritis individuals. Methods: 30 subjects with symptoms of knee osteoarthritis were randomly distributed into 2 groups 15 in each group. PNF Hold relax stretching along with moist heat is compared to Static stretching along with moist heat. Pain was measured by Visual Analogue Scale (VAS and hamstring flexibility by Active knee Extension Range of Motion (AKEROM by universal goniometer. Measurements are taken pre and post intervention. Results: The results indicated PNF Hold relax stretching along with moist heat showed a statistically significant improvement in pain (p<0.05 and improvement in hamstring flexibility (p<0.05 when compared to Static stretching along with moist heat. Conclusion: Subjects with PNF Hold relax stretching along with moist heat showed significant improvement in pain reduction and improving hamstring flexibility than Static stretching along with moist heat.

  9. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

    OpenAIRE

    O'Sullivan, Kieran; Murray, Elaine; Sainsbury, David

    2009-01-01

    Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured indi...

  10. LABOR GYMNASTICS: STRETCHING EXERCISE X FLEXIONAMENT

    Directory of Open Access Journals (Sweden)

    Jacqueline Amorin Anchieta Borges da Silva, Isabel Cristina Taranto e Fernanda Piasecki

    2006-12-01

    Full Text Available Nowadays, there are many opportunities for the society to live a healthful and long life. At the same time, never people was so sedentary and without harmony. Without a healthy body and with “an occupied mind” the human loses exactly what more it needs: the disposal to produce, to coexist and to live a good life. In this context, the present research aimed to revise some terms related to labor gymnastics, which is focused in the prevention of risks related to hours of working and in the reduction of muscular tension levels that may be originated during a day of work. Thus, the present study will make a differentiation between the use of stretching and flexionament during labor gymnastic sessions.

  11. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Science.gov (United States)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  12. Aerothermodynamic properties of stretched flames in enclosures

    Science.gov (United States)

    Rotman, D. A.; Oppenheim, A. K.

    Flames are stretched by being pulled along their frontal surface by the flow field in which they reside. Their trajectories tend to approach particle paths, acquiring eventually the role of contact boundaries, -interfaces between the burnt and unburnt medium that may broaden solely as a consequence of diffusion. Fundamental properties of flow fields governing such flames are determined here on the basis of the zero Mach number model, providng a rational method of approach to the computational analysis of combustion fields in enclosures where, besides the aerodynamic properties flow, the thermodynamic process of compression must be taken into account. To illustrate its application, the method is used to reveal the mechanism of formation of a tulip-shape flame in a rectangular enclosure under nonturbulent flow conditions.

  13. Electroforesis of Whey and Stretching Water Protein of Mozzarella Cheese Production from Factorial Experimental of Coagulation and Stretching Temperature

    Directory of Open Access Journals (Sweden)

    Purwadi Purwadi

    2012-02-01

    Full Text Available The use of lime juice as acidifier in the making of Mozzarella cheese was aimed to learn the protein profile of whey and stretching water produced with treatment of coagulation and stretching temperature. The treatment of coagulation temperature was G1 = 30oC, G2 = 35oC, G3 = 40oC, and G4 = 45oC, and the treatment of stretching temperature was M1 = 70oC, M2 = 75oC, M3 = 80oC, and M4 = 85oC. The research result showed that coagulation temperature of 30 and 35 oC gave the same protein profile of whey as well as coagulation temperature of 40 and 45oC, while coagulation temperature of 30 and 35oC with coagulation temperatur of 40 and 45oC gave different protein profile of whey. Different coagulation temperature gave different protein profile of whey and stretching water, while different stretching temperature gave the same protein profile of stretching water. Coagulation temperature of 30 and 35oC gave the same protein profile of stretching water as well as coagulation temperature of 40 and 45oC, while coagulation temperature of 30 and 35oC with temperature of 40 and 45oC gave different protein profile of stretching water. Keywords: protein profile, Mozzarella cheese, coagulation temperature, stretching temperature

  14. EFFICACY OF MODIFIED PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING WITH CRYOTHERAPY OVER MANUAL PASSIVE STRETCHING WITH CRYOTHERAPY ON HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    Shamik Bhattacharjee

    2016-04-01

    Full Text Available Background: Healthy individuals, to ease and accomplish their activities of daily living they need flexible body without any tightness in the muscles, particularly those used for a definite function. Cooling soft tissues in a lengthened position after stretching has been shown to promote more lasting increases in soft tissue length and minimize post stretch muscle soreness. There are less documented studies which compared modified proprioceptive neuromuscular facilitation (PNF stretch over passive manual stretch with cold application commonly after the interventions. Methods: Thirty high school going healthy students were divided into two groups- Group I received Passive Manual stretching (n=15 and Group II received modified PNF stretching (n=15 and both groups received cold application after the interventions for 10 minutes commonly for 5 days. ROM was taken on day 1, day 5 and day 7. Results: After day 7, Group II with Modified PNF stretching along with cold application showed a significant increase in range of motion tested with active knee extension test (AKET. Conclusion: Modified PNF stretching is considered to be the effective intervention in increasing and maintaining ROM in AKET over passive manual stretching with cold applications commonly after the interventions.

  15. Immediate Effects of Proprioceptive Neuromuscular Facilitation Stretching Programs Compared With Passive Stretching Programs for Hamstring Flexibility: A Critically Appraised Topic.

    Science.gov (United States)

    Hill, Kristian J; Robinson, Kendall P; Cuchna, Jennifer W; Hoch, Matthew C

    2017-11-01

    Clinical Scenario: Increasing hamstring flexibility through clinical stretching interventions may be an effective means to prevent hamstring injuries. However the most effective method to increase hamstring flexibility has yet to be determined. For a healthy individual, are proprioceptive neuromuscular facilitation (PNF) stretching programs more effective in immediately improving hamstring flexibility when compared with static stretching programs? Summary of Key Findings: A thorough literature search returned 195 possible studies; 5 studies met the inclusion criteria and were included. Current evidence supports the use of PNF stretching or static stretching programs for increasing hamstring flexibility. However, neither program demonstrated superior effectiveness when examining immediate increases in hamstring flexibility. Clinical Bottom Line: There were consistent findings from multiple low-quality studies that indicate there is no difference in the immediate improvements in hamstring flexibility when comparing PNF stretching programs to static stretching programs in physically active adults. Strength of Recommendation: Grade B evidence exists that PNF and static stretching programs equally increase hamstring flexibility immediately following the stretching program.

  16. Theoretical study of the C-H/O-H stretching vibrations in malonaldehyde

    Science.gov (United States)

    Pitsevich, G. A.; Malevich, A. E.; Kozlovskaya, E. N.; Doroshenko, I. Yu.; Pogorelov, V. E.; Sablinskas, V.; Balevicius, V.

    2015-06-01

    IR and Raman spectra of the malonaldehyde molecule and its deuterated analogues were calculated in the B3LYP/cc-pVQZ approximation. Anharmonicity effects were taken into account both in the context of a standard model of the second order perturbation theory and by constructing the potential energy surfaces (PES) with a limited number of dimensions using the Cartesian coordinates of the hydroxyl hydrogen atom and the stretching coordinates of С-Н, C-D, O-H, and O-D bonds. It was shown that in each of the two equivalent forms of the molecule, besides the global minimum, an additional local minimum at the PES is formed with the energy more than 3000 cm-1 higher than the energy in the global minimum. Calculations carried out by constructing the 2D and 3D PESs indicate a high anharmonicity level and multiple manifestations of the stretching О-Н vibrations, despite the fact that the model used does not take into account the splitting of the ground-state and excited vibrational energy levels. In particular, the vibration with the frequency 3258 cm-1 may be associated with proton transfer to the region of a local minimum of energy. Comparing the results obtained with the experimental data presented in the literature allowed us to propose a new variant of bands assignments in IR and Raman spectra of the molecule in the spectral region 2500-3500 cm-1.

  17. Parameterization of rotational spectra

    International Nuclear Information System (INIS)

    Zhou Chunmei; Liu Tong

    1992-01-01

    The rotational spectra of the strongly deformed nuclei with low rotational frequencies and weak band mixture are analyzed. The strongly deformed nuclei are commonly encountered in the rare-earth region (e. g., 150 220). A lot of rotational band knowledge are presented

  18. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  19. Effects of acute stretching on the maximal expression of strength ...

    African Journals Online (AJOL)

    This study compared the effects of four treatments (n = 12 each) [10 minutes of quiet sitting, without stretching (NS); two minutes warm up on an arm ergometer at 25 watts resistance (WU); 10 second-hold static stretching (each) of the shoulder, chest and arm muscle groups (ST10); and two sets of 20 second-hold static ...

  20. The stretch reflex and the contributions of C David Marsden.

    Science.gov (United States)

    Bhattacharyya, Kalyan B

    2017-01-01

    The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail, and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

  1. Chaperones in Polyglutamine Aggregation : Beyond the Q-Stretch

    NARCIS (Netherlands)

    Kuiper, E. F. E.; de Mattos, Eduardo P.; Jardim, Laura B.; Kampinga, Harm H.; Bergink, Steven

    2017-01-01

    Expanded polyglutamine (polyQ) stretches in at least nine unrelated proteins lead to inherited neuronal dysfunction and degeneration. The expansion size in all diseases correlates with age at onset (AO) of disease and with polyQ protein aggregation, indicating that the expanded polyQ stretch is the

  2. Stretched exponential relaxation and ac universality in disordered dielectrics

    DEFF Research Database (Denmark)

    Milovanov, Alexander V.; Rypdal, Kristoffer; Juul Rasmussen, Jens

    2007-01-01

    are stretched exponential character of dielectric relaxation, power-law power spectral density, and anomalous dependence of ac conduction coefficient on frequency. We propose a self-consistent model of dielectric relaxation in which the relaxations are described by a stretched exponential decay function...

  3. Time and direction preparation of the long latency stretch reflex.

    Science.gov (United States)

    Nikaido, Yasutaka; Hatanaka, Ryota; Jono, Yasutomo; Nomura, Yoshifumi; Tani, Keisuke; Chujo, Yuta; Hiraoka, Koichi

    2016-06-01

    This study investigated time and direction preparation of motor response to force load while intending to maintain the finger at the initial neutral position. Force load extending or flexing the index finger was given while healthy humans intended to maintain the index finger at the initial neutral position. Electromyographic activity was recorded from the first dorsal interosseous muscle. A precue with or without advanced information regarding the direction of the forthcoming force load was given 1000ms before force load. Trials without the precue were inserted between the precued trials. A long latency stretch reflex was elicited by force load regardless of its direction, indicating that the long latency stretch reflex is elicited not only by muscle stretch afferents, but also by direction-insensitive sensations. Time preparation of motor response to either direction of force load enhanced the long latency stretch reflex, indicating that time preparation is not mediated by afferent discharge of muscle stretch. Direction preparation enhanced the long latency stretch reflex and increased corticospinal excitability 0-20ms after force load when force load was given in the direction stretching the muscle. These enhancements must be induced by preset of the afferent pathway mediating segmental stretch reflex. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. The stretch reflex and the contributions of C David Marsden

    Directory of Open Access Journals (Sweden)

    Kalyan B Bhattacharyya

    2017-01-01

    Full Text Available The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail , and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

  5. Transparent conducting film: Effect of mechanical stretching to ...

    Indian Academy of Sciences (India)

    We describe in this paper a transparent conducting film (TCF). It is a fibrous layer of multiwalled carbon nanotubes (MWNTs), labeled a dilute CNT mat, that was prepared and unidirectionally stretched to improve both the optical and electrical properties. After stretching by 80% strain, transmittance at 550 nm wavelength ...

  6. The effects of acute self myofascial release (MFR) and stretching ...

    African Journals Online (AJOL)

    Baseline measurements were taken initially and then participants were randomly divided into four groups (control [n=10, static stretching [n=10], dynamic stretching [n=10] and self MFR [n=10]). Each group performed a 60-minute intervention. During the intervention programme the various groups took part in prescribed ...

  7. Transparent conducting film: Effect of mechanical stretching to ...

    Indian Academy of Sciences (India)

    Administrator

    The number of pixels inside a rectangle counted on the Adobe Photoshop. Figure 6. Sheet resistance and transmittance at 550 nm wave- length of a dilute CNT mat before and after stretch. Five sam- ples were stretched by 40 and 110% strain respectively and average data is shown in each case. A polyurethane elastomer.

  8. Does Postexercise Static Stretching Alleviate Delayed Muscle Soreness?

    Science.gov (United States)

    Buroker, Katherine C.; Schwane, James A.

    1989-01-01

    Because many experts recommend stretching after exercise to relieve muscle soreness, 23 subjects performed a 30-minute step test to induce delayed muscle soreness. There was neither temporary relief of pain immediately after stretching nor a reduction in pain during the 3-day postexercise period. (Author/SM)

  9. Mechanical stretch influence on lifetime of dielectric elastomer films

    NARCIS (Netherlands)

    Iannarelli, A.; Ghaffarian Niasar, M.; Bar-Cohen, Yoseph

    2017-01-01

    Film pre-stretching is a widely adopted solution to improve dielectric strength of the DEA systems. However, to date, long term reliability of this solution has not been investigated. In this work it is explored how the dielectric elastomer lifetime is affected by film pre-stretching. The dielectric

  10. The effect of calf stretching box on stretching calf muscle compliance: a prospective, randomized single-blinded controlled trial.

    Science.gov (United States)

    Chadchavalpanichaya, Navaporn; Srisawasdi, Gulapar; Suwannakin, Atchara

    2010-12-01

    To study the effect of calf stretching box usage in increasing the compliance of performing calf stretching exercise as compared to the conventional exercise method. To study the effect of calf stretching box usage in decreasing the calf muscle tightness and complications as compared to the conventional exercise method. Eighty patients older than 45 years old with calf muscles tightness were enrolled in a prospective, randomized single-blinded controlled trial at the out-patient Rehabilitation medicine clinic, Siriraj Hospital, Bangkok Thailand between April and August 2009. Patients were randomized into two groups, the study group (stretching by using calf stretching box) and the control group (stretching by the conventional exercise method). Patients in both groups were asked to hold the stretch for at least 1 minute and to perform the stretching program at least two times per day, every day for two weeks. Furthermore, they were asked to record the real frequency and duration of their exercise and complications in a logbook every day. Thirty-eight patients in each group completed the study. The baseline characteristics of the patients in both groups were similar. The study group had higher frequency and longer duration of performing calf stretching exercise than the control group. They also reported more decrease of calf muscle tightness with less pain complication (shoulder pain, knee pain, low back pain, and calf muscle pain) than the control group (p calf muscle and degree of ankle range of motion between the two groups. Stretching calf muscle with calf stretching box can increase compliance, decrease calf muscle tightness and decrease complications when compared with the conventional exercise method.

  11. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

    Science.gov (United States)

    O'Sullivan, Kieran; Murray, Elaine; Sainsbury, David

    2009-04-16

    Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Across both groups, there was a significant main effect for time (p static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. ACTRN12608000638336.

  12. Stretch reflex regulation in healthy subjects and patients with spasticity

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo; Petersen, Nicolas; Crone, Clarissa

    2005-01-01

    In recent years, part of the muscle resistance in spastic patients has been explained by changes in the elastic properties of muscles. However, the adaptive spinal mechanisms responsible for the exaggeration of stretch reflex activity also contribute to muscle stiffness. The available data suggest...... of the spastic symptoms. A recent finding also shows no sign of exaggerated stretch reflexes in muscles voluntarily activated by the spastic patient in general. This is easily explained by the control of stretch reflex activity in healthy subjects. In healthy subjects, the stretch reflex activity is increased...... movements, antagonist muscles should remain silent and maximally relaxed. This is ensured by increasing transmission in several spinal inhibitory pathways. In spastic patients, this control is inadequate, and therefore stretch reflexes in antagonist muscles are easily evoked at the beginning of voluntary...

  13. Bruxism: Is There an Indication for Muscle-Stretching Exercises?

    Science.gov (United States)

    Gouw, Simone; de Wijer, Anton; Creugers, Nico Hj; Kalaykova, Stanimira I

    Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism. However, most studies of muscle-stretching exercises have mainly focused on their influence on performance (eg, range of motion, coordination, and muscle strength) of the limb or trunk muscles of healthy individuals or individuals with sports-related injuries. Very few have investigated stretching of the human masticatory muscles and none muscle-stretching exercises in the management of (sleep) bruxism. This article reviews the literature on muscle-stretching exercises and their potential role in the management of sleep bruxism or its consequences in the musculoskeletal system.

  14. Acute effect of different stretching methods on isometric muscle strength

    Directory of Open Access Journals (Sweden)

    Gabriel Vasconcellos de Lima Costa e Silva

    2014-03-01

    This study investigated the acute effect of static stretching methods (SS and proprioceptive neuromuscular facilitation (PNF on the static muscle strength (SMS. Eleven young male subjects with strength training experience, performed 3 tests with a 48h interval between them, randomly selected, where each one subject carried out all procedures: a hand grip without stretching; b hand grip preceded by static stretching of wrist flexors muscles; c hand grip preceded by PNF stretching of wrist flexors muscles. The Shapiro-Wilk test verified the normality of data, and a one-way ANOVA with repeated measures, followed by Tukey’s post hoc test, evaluated the differences between the groups. The significance was set at p 0.05. In conclusion, both stretching methods had caused negative effects on isometric strength, reducing its levels.

  15. Linear and nonlinear buckling analysis of a locally stretched plate

    Energy Technology Data Exchange (ETDEWEB)

    Kilardj, Madina; Ikhenzzen, Ghania [University of Sciences and Technology Houari Boumediene (U.S.T.H.B), Bab Ezzouar, Algiers (Algeria); Merssager, Tanguy; Kanit, Toufik [Laboratoire de Mecanique de Lille Universite Lille 1, Cite ScientifiqueVilleneuve d' Ascq cedex (France)

    2016-08-15

    Uniformly stretched thin plates do not buckle unless they are in special boundary conditions. However, buckling commonly occurs around discontinuities, such as cracks, cuts, narrow slits, holes, and different openings, of such plates. This study aims to show that buckling can also occur in thin plates that contain no defect or singularity when the stretching is local. This specific stability problem is analyzed with the finite element method. A brief literature review on stretched plates is presented. Linear and nonlinear buckling stress analyses are conducted for a partially stretched rectangular plate, and various load cases are considered to investigate the influence of the partial loading expanse on the critical tensile buckling load. Results are summarized in iso-stress areas, tables and graphs. Local stretching on one end of the plate induces buckling in the thin plate even without geometrical imperfection.

  16. Acute effects of different stretching durations on passive torque, mobility, and isometric muscle force.

    Science.gov (United States)

    Matsuo, Shingo; Suzuki, Shigeyuki; Iwata, Masahiro; Banno, Yasuhiro; Asai, Yuji; Tsuchida, Wakako; Inoue, Takayuki

    2013-12-01

    Static stretching is widely applied in various disciplines. However, the acute effects of different durations of stretching are unclear. Therefore, this study was designed to investigate the acute effects of different stretching durations on muscle function and flexibility, and provide an insight into the optimal duration of static stretching. This randomized crossover trial included 24 healthy students (17 men and 7 women) who stretched their right hamstrings for durations of 20, 60, 180, and 300 seconds in a random order. The following outcomes were assessed using an isokinetic dynamometer as markers of lower-limb function and flexibility: static passive torque (SPT), dynamic passive torque (DPT), stiffness, straight leg raise (SLR), and isometric muscle force. Static passive torque was significantly decreased after all stretching durations (p stretching compared with that after 20-second stretching, and stiffness decreased significantly after 180- and 300-second stretching (p stretching (p stretching durations (p stretching than after 20-second stretching and higher after 300-second stretching than after 60-second stretching (p muscle force significantly decreased after all stretching durations (p stretching is associated with a decrease in SPT but an increase in SLR. Over 180 seconds of stretching was required to decrease DPT and stiffness, but isometric muscle force decreased regardless of the stretching duration. In conclusion, these results indicate that longer durations of stretching are needed to provide better flexibility.

  17. Pre-exercise stretching does not impact upon running economy.

    Science.gov (United States)

    Hayes, Philip R; Walker, Adrian

    2007-11-01

    Pre-exercise stretching has been widely reported to reduce performance in tasks requiring maximal or near-maximal force or torque. The purpose of this study was to compare the effects of 3 different pre-exercise stretching routines on running economy. Seven competitive male middle and long-distance runners (mean +/- SD) age: 32.5 +/- 7.7 years; height: 175.0 +/- 8.8 cm; mass: 67.8 +/- 8.6 kg; V(.-)O2max: 66.8 +/- 7.0 ml x kg(-1) x min(-1)) volunteered to participate in this study. Each participant completed 4 different pre-exercise conditions: (a) a control condition, (b) static stretching, (c) progressive static stretching, and (d) dynamic stretching. Each stretching routine consisted of 2 x 30-second stretches for each of 5 exercises. Dependent variables measured were sit and reach test before and after each pre-exercise routine, running economy (ml x kg(-1) x km(-1)), and steady-state oxygen uptake (ml x kg(-1) x min(-1)), which were measured during the final 3 minutes of a 10-minute run below lactate threshold. All 3 stretching routines resulted in an increase in the range of movement (p = 0.008). There was no change in either running economy (p = 0.915) or steady-state V(.-)O2 (p = 0.943). The lack of change in running economy was most likely because it was assessed after a period of submaximal running, which may have masked any effects from the stretching protocols. Previously reported reductions in performance have been attributed to reduced motor unit activation, presumably IIX. In this study, these motor units were likely not to have been recruited; this may explain the unimpaired performance. This study suggests that pre-exercise stretching has no impact upon running economy or submaximal exercise oxygen cost.

  18. Randomized Controlled Trial Comparing Orthosis Augmented by Either Stretching or Stretching and Strengthening for Stage II Tibialis Posterior Tendon Dysfunction.

    Science.gov (United States)

    Houck, Jeff; Neville, Christopher; Tome, Josh; Flemister, Adolph

    2015-09-01

    The value of strengthening and stretching exercises combined with orthosis treatment in a home-based program has not been evaluated. The purpose of this study was to compare the effects of augmenting orthosis treatment with either stretching or a combination of stretching and strengthening in participants with stage II tibialis posterior tendon dysfunction (TPTD). Participants included 39 patients with stage II TPTD who were recruited from a medical center and then randomly assigned to a strengthening or stretching treatment group. Excluding 3 dropouts, there were 19 participants in the strengthening group and 17 in the stretching group. The stretching treatment consisted of a prefabricated orthosis used in conjunction with stretching exercises. The strengthening treatment consisted of a prefabricated orthosis used in conjunction with the stretching and strengthening exercises. The main outcome measures were self-report (ie, Foot Function Index and Short Musculoskeletal Function Assessment) and isometric deep posterior compartment strength. Two-way analysis of variance was used to test for differences between groups at 6 and 12 weeks after starting the exercise programs. Both groups significantly improved in pain and function over the 12-week trial period. The self-report measures showed minimal differences between the treatment groups. There were no differences in isometric deep posterior compartment strength. A moderate-intensity, home-based exercise program was minimally effective in augmenting orthosis wear alone in participants with stage II TPTD. Level I, prospective randomized study. © The Author(s) 2015.

  19. X-ray absorption spectra and emission spectra of plasmas

    International Nuclear Information System (INIS)

    Peng Yonglun; Yang Li; Wang Minsheng; Li Jiaming

    2002-01-01

    The author reports a theoretical method to calculate the resolved absorption spectra and emission spectra (optically thin) of hot dense plasmas. Due to its fully relativistic treatment incorporated with the quantum defect theory, it calculates the absorption spectra and emission spectra for single element or multi-element plasmas with little computational efforts. The calculated absorption spectra of LTE gold plasmas agree well with the experimental ones. It also calculates the optical thin emission spectra of LTE gold plasmas, which is helpful to diagnose the plasmas of relevant ICF plasmas. It can also provide the relevant parameters such as population density of various ionic stages, precise radiative properties for ICF studies

  20. Reflectors Made from Membranes Stretched Between Beams

    Science.gov (United States)

    Dooley, Jennifer; Dragovan, Mark; Tolomeo, Jason

    2009-01-01

    Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such reflector, the curvature of the two beams would define the reflector shape required for the intended application. For example, the beams could be curved to define a reflector of parabolic cross section, so that light incident along the axis of symmetry perpendicular to the cylindrical axis would be focused to a line. In addition, by applying suitable forces to the ends of the beams, one could bend the beams to adjust the reflector surface figure to within a precision of the order of the wavelength of the radiation to be reflected. The figure depicts an example of beams shaped so that in the absence of applied forces, each would be flat on one side and would have a radius of curvature R on the opposite side. Alternatively, the curvature of the reflector-membrane side could be other than circular. In general, the initial curvature would be chosen to optimize the final reflector shape. Then by applying forces F between the beam ends in the positions and orientations shown in the figure, one could bend beams to adjust their shape to a closer approximation of the desired precise circular or noncircular curvature.

  1. Linear viscoelastic characterization from filament stretching rheometry

    DEFF Research Database (Denmark)

    Wingstrand, Sara Lindeblad; Alvarez, Nicolas J.; Hassager, Ole

    Traditionally, linear viscoelasticity is measured using small amplitude oscillatory shear flow. Due to experimental difficulties, shear flows are predominately confined to the linear and mildly nonlinear regime. On the other hand, extensional flows have proven more practical in measuring viscoela......Traditionally, linear viscoelasticity is measured using small amplitude oscillatory shear flow. Due to experimental difficulties, shear flows are predominately confined to the linear and mildly nonlinear regime. On the other hand, extensional flows have proven more practical in measuring...... viscoelasticity well into the nonlinear regime. Therefore at present, complete rheological characterization of a material requires two apparatuses: a shear and an extensional rheometer. This work is focused on developing a linear viscoelastic protocol for the filament stretching rheometer (FSR) in order...... to measure both linear and nonlinear dynamics on a single apparatus. With a software modification to the FSR motor control, we show that linear viscoelasticity can be measured via small amplitude squeeze flow (SASF). Squeeze flow is a combination of both shear and extensional flow applied by axially...

  2. Thermoluminescence spectra of amethyst

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q. [Suzhou Railway Teachers College (China). Dept. of Physics; Yang, B. [Beijing Normal University (China). Dept. of Physics; Wood, R.A.; White, D.R.R.; Townsend, P.D.; Luff, B.J. [Sussex Univ., Brighton (United Kingdom). School of Mathematical and Physical Sciences

    1994-04-01

    Thermoluminescence and cathodoluminescence data from natural and synthetic amethyst and synthetic quartz samples are compared. The spectra include features from the quartz host lattice and from impurity-generated recombination sites. Emission features exist throughout the wavelength range studied, 250-800 nm. The near infrared emission at 740-750 nm appears to be characteristic of the amethyst and is proposed to be due to Fe ion impurity. (Author).

  3. Pattern recognition in spectra

    Science.gov (United States)

    Gebran, M.; Paletou, F.

    2017-06-01

    We present a new automated procedure that simultaneously derives the effective temperature Teff, surface gravity log g, metallicity [Fe/H], and equatorial projected rotational velocity ve sin i for stars. The procedure is inspired by the well-known PCA-based inversion of spectropolarimetric full-Stokes solar data, which was used both for Zeeman and Hanle effects. The efficiency and accuracy of this procedure have been proven for FGK, A, and late type dwarf stars of K and M spectral types. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones.

  4. Estimating Spectra from Photometry

    Science.gov (United States)

    Kalmbach, J. Bryce; Connolly, Andrew J.

    2017-12-01

    Measuring the physical properties of galaxies such as redshift frequently requires the use of spectral energy distributions (SEDs). SED template sets are, however, often small in number and cover limited portions of photometric color space. Here we present a new method to estimate SEDs as a function of color from a small training set of template SEDs. We first cover the mathematical background behind the technique before demonstrating our ability to reconstruct spectra based upon colors and then compare our results to other common interpolation and extrapolation methods. When the photometric filters and spectra overlap, we show that the error in the estimated spectra is reduced by more than 65% compared to the more commonly used techniques. We also show an expansion of the method to wavelengths beyond the range of the photometric filters. Finally, we demonstrate the usefulness of our technique by generating 50 additional SED templates from an original set of 10 and by applying the new set to photometric redshift estimation. We are able to reduce the photometric redshifts standard deviation by at least 22.0% and the outlier rejected bias by over 86.2% compared to original set for z ≤ 3.

  5. Pattern recognition in spectra

    International Nuclear Information System (INIS)

    Gebran, M; Paletou, F

    2017-01-01

    We present a new automated procedure that simultaneously derives the effective temperature T eff , surface gravity log g , metallicity [ Fe/H ], and equatorial projected rotational velocity v e sin i for stars. The procedure is inspired by the well-known PCA-based inversion of spectropolarimetric full-Stokes solar data, which was used both for Zeeman and Hanle effects. The efficiency and accuracy of this procedure have been proven for FGK, A, and late type dwarf stars of K and M spectral types. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones. (paper)

  6. STRETCH FABRICS IN LEATHER MANUFACTURING: PERFORMANCE PROPERTIES OF STRECH LEATHERS

    Directory of Open Access Journals (Sweden)

    ORK Nilay

    2016-05-01

    Full Text Available Product variability of manufactured leather goods such as garment leathers could be closely related to the wear comfort because each material forming the garments are affected the comfort properties of the products. Considering the significant demand to elastic woven stretch fabrics and the advantages provided to leather goods like allowing easy body movements, well-fitting and keeping the shape make the use of stretch fabrics focus in interest. In this study, the performance properties of stretch leathers, leathers and spandex fabrics were presented and the differences between the characteristic properties of the leathers were described. For this purpose, physical characteristics of leathers were investigated in terms of thickness, weight, drape ability, stiffness, bending stiffness, air and water vapor permeability. The drape ability, stiffness and bending stiffness properties were significantly affected by the stretch fabrics laminated on the suede side of the leathers. The drape ability, stiffness and bending values were increased due to the implementation of stretch fabrics. There was no significant difference between the air permeability values of the leathers prior and after the implementation of stretch fabrics in contrast to water vapor permeability. The results of this study showed that the aesthetic behavior of clothing materials such as drape and stiffness properties as well as water vapor permeability was mainly affected from the implementation of the stretch fabrics.

  7. Magnitude and duration of stretch modulate fibroblast remodeling.

    Science.gov (United States)

    Balestrini, Jenna L; Billiar, Kristen L

    2009-05-01

    Mechanical cues modulate fibroblast tractional forces and remodeling of extracellular matrix in healthy tissue, healing wounds, and engineered matrices. The goal of the present study is to establish dose-response relationships between stretch parameters (magnitude and duration per day) and matrix remodeling metrics (compaction, strength, extensibility, collagen content, contraction, and cellularity). Cyclic equibiaxial stretch of 2-16% was applied to fibroblast-populated fibrin gels for either 6 h or 24 h/day for 8 days. Trends in matrix remodeling metrics as a function of stretch magnitude and duration were analyzed using regression analysis. The compaction and ultimate tensile strength of the tissues increased in a dose-dependent manner with increasing stretch magnitude, yet remained unaffected by the duration in which they were cycled (6 h/day versus 24 h/day). Collagen density increased exponentially as a function of both the magnitude and duration of stretch, with samples stretched for the reduced duration per day having the highest levels of collagen accumulation. Cell number and failure tension were also dependent on both the magnitude and duration of stretch, although stretch-induced increases in these metrics were only present in the samples loaded for 6 h/day. Our results indicate that both the magnitude and the duration per day of stretch are critical parameters in modulating fibroblast remodeling of the extracellular matrix, and that these two factors regulate different aspects of this remodeling. These findings move us one step closer to fully characterizing culture conditions for tissue equivalents, developing improved wound healing treatments and understanding tissue responses to changes in mechanical environments during growth, repair, and disease states.

  8. AI-augmented time stretch microscopy

    Science.gov (United States)

    Mahjoubfar, Ata; Chen, Claire L.; Lin, Jiahao; Jalali, Bahram

    2017-02-01

    Cell reagents used in biomedical analysis often change behavior of the cells that they are attached to, inhibiting their native signaling. On the other hand, label-free cell analysis techniques have long been viewed as challenging either due to insufficient accuracy by limited features, or because of low throughput as a sacrifice of improved precision. We present a recently developed artificial-intelligence augmented microscope, which builds upon high-throughput time stretch quantitative phase imaging (TS-QPI) and deep learning to perform label-free cell classification with record high-accuracy. Our system captures quantitative optical phase and intensity images simultaneously by frequency multiplexing, extracts multiple biophysical features of the individual cells from these images fused, and feeds these features into a supervised machine learning model for classification. The enhanced performance of our system compared to other label-free assays is demonstrated by classification of white blood T-cells versus colon cancer cells and lipid accumulating algal strains for biofuel production, which is as much as five-fold reduction in inaccuracy. This system obtains the accuracy required in practical applications such as personalized drug development, while the cells remain intact and the throughput is not sacrificed. Here, we introduce a data acquisition scheme based on quadrature phase demodulation that enables interruptionless storage of TS-QPI cell images. Our proof of principle demonstration is capable of saving 40 TB of cell images in about four hours, i.e. pictures of every single cell in 10 mL of a sample.

  9. Acute effect of constant torque and angle stretching on range of motion, muscle passive properties, and stretch discomfort perception.

    Science.gov (United States)

    Cabido, Christian E T; Bergamini, Juliana C; Andrade, André G P; Lima, Fernando V; Menzel, Hans J; Chagas, Mauro H

    2014-04-01

    The aim of the present study was to compare the acute effects of constant torque (CT) and constant angle (CA) stretching exercises on the maximum range of motion (ROMmax), passive stiffness (PS), and ROM corresponding to the first sensation of tightness in the posterior thigh (FSTROM). Twenty-three sedentary men (age, 19-33 years) went through 1 familiarization session and afterward proceeded randomly to both CA and CT treatment stretching conditions, on separate days. An isokinetic dynamometer was used to analyze hamstring muscles during passive knee extension. The subjects performed 4 stretches of 30 seconds each with a 15-second interval between them. In the CA stretching, the subject reached a certain ROM (95% of ROMmax), and the angle was kept constant. However, in the CT stretching exercise, the volunteer reached a certain resistance torque (corresponding to 95% of ROMmax) and it was kept constant. The results showed an increase in ROMmax for both CA and CT (p stretch may be explained by greater changes in the biomechanical properties of the muscle-tendon unit and stretch tolerance, as indicated by the results of PS and FSTROM.

  10. Deconvolution of Positrons' Lifetime spectra

    International Nuclear Information System (INIS)

    Calderin Hidalgo, L.; Ortega Villafuerte, Y.

    1996-01-01

    In this paper, we explain the iterative method previously develop for the deconvolution of Doppler broadening spectra using the mathematical optimization theory. Also, we start the adaptation and application of this method to the deconvolution of positrons' lifetime annihilation spectra

  11. Nuclear Spectra from Skyrmions

    International Nuclear Information System (INIS)

    Manton, N.

    2009-01-01

    For some time now, the Skyrme model has been studied as an effective nonlinear field theory in nuclear physics. Its classical, stable soliton solutions, called Skyrmions, have a conserved topological charge which is identified with baryon number. A quantized Skyrmion models a nucleus. Skyrmions with baryon number a multiple of four are structurally similar to the cluster structures well-known in the a-particle model. The most convenient quantization scheme treats a Skyrmion as a rigid body in space and isospin space, and quantizes just the collective rotational motion. Some selected vibrational modes of Skyrmions may be included too. This approach has been applied previously to Skyrmions up to baryon number about 6, by Braaten and Carson, Kopeliovich, Walhout, and others. Recently, Battye, Manton, Sutcliffe and Wood have calculated the moment of inertia tensors in space and isospace for Skyrmions up to baryon number 12. The allowed spin and isospin states have been found, and the energy spectra calculated. These spectra agree quite well with experimental spectra of several light nuclei, including 6 L i, 8 B e, 1 2C , and their various isotopes. However, for this to work, the length scale needs to be set rather larger than the traditional value determined by Adkins and Nappi using the nucleon and delta resonance masses. The most interesting theoretical feature of these calculations is that isospin and spin excitations are treated in a uniform way. There are quite subtle constraints on the possible spin and isospin values, because of the classical symmetries of each Skyrmion. Manton and his students, and Battye and Sutcliffe, have published a number of papers on classical and quantized Skyrmions in journals and on the arXiv. They are also jointly contributing an invited chapter on Skyrmions and Nuclei to the book The Multifaceted Skyrmion, currently being edited by G. Brown and M. Rho.(author)

  12. A FEM-based method using harmonic overtones to determine the effective elastic, dielectric, and piezoelectric parameters of freely vibrating thick piezoelectric disks.

    Science.gov (United States)

    Jonsson, Ulf G; Andersson, Britt M; Lindahl, Olof A

    2013-01-01

    To gain an understanding of the electroelastic properties of tactile piezoelectric sensors used in the characterization of soft tissue, the frequency-dependent electric impedance response of thick piezoelectric disks has been calculated using finite element modeling. To fit the calculated to the measured response, a new method was developed using harmonic overtones for tuning of the calculated effective elastic, piezoelectric, and dielectric parameters. To validate the results, the impedance responses of 10 piezoelectric disks with diameter-to-thickness ratios of 20, 6, and 2 have been measured from 10 kHz to 5 MHz. A two-dimensional, general purpose finite element partial differential equation solver with adaptive meshing capability run in the frequency-stepped mode, was used. The equations and boundary conditions used by the solver are presented. Calculated and measured impedance responses are presented, and resonance frequencies have been compared in detail. The comparison shows excellent agreement, with average relative differences in frequency of 0.27%, 0.19%, and 0.54% for the samples with diameter-to-thickness ratios of 20, 6, and 2, respectively. The method of tuning the effective elastic, piezoelectric, and dielectric parameters is an important step toward a finite element model that describes the properties of tactile sensors in detail.

  13. Effects of Static Stretching and Playing Soccer on Knee Laxity

    NARCIS (Netherlands)

    Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W.; Freiwald, Juergen

    2015-01-01

    Objective: This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Design: Randomized controlled trial. Setting: University biomechanics laboratory. Participants: Thirty-one athletes were randomly assigned into

  14. Functional finishes of stretch cotton fabrics.

    Science.gov (United States)

    Ibrahim, N A; Amr, A; Eid, B M; Almetwally, A A; Mourad, M M

    2013-11-06

    Functionalized cotton cellulose/spandex woven fabrics with different structures namely plain (1/1), twill (2/2) and satin were produced. Factors affecting the imparted functional properties such as weave structure and constituents of the finishing formulations including ether or ester cross-linker and catalyst type, silicone-micro-emulsion, water/oil repellent, Ag-NP(,)s and TiO2-NP(,)s were studied. The treated fabrics were found to have easy care property together with one or more of the imparted functional properties such as soft-handle, water/oil repellence, antibacterial, UV-protection and self cleaning. The effectiveness of the imparted properties is not seriously affected even after 10 washing cycles. Surface modifications as well as the composition of certain samples were confirmed by SEM images and EDX spectra. Mode of interactions was also suggested. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. EFFECT OF STATIC STRETCHING ON STRENGTH OF HAMSTRING MUSCLE

    Directory of Open Access Journals (Sweden)

    Shweta P Pachpute

    2016-04-01

    Full Text Available Background: Flexibility is an indisputable component of fitness defined as the ability to move a single joint or series of joints through an unrestricted pain free range of motion. Static stretching consists of stretching a muscle or group of muscle to its farthest point and then maintaining or holding that position. The literature supports that muscles are capable of exerting their greatest strength when they are fully lengthen. Hence this study was conducted to find the effect of static stretching on hamstring muscle. Methods: The study was experimental study design. 40 samples were selected by purposive sampling method. Flexibility of the hamstring muscle unilaterally right side (arbitrarily chosen was measured by active knee extension test of all the subjects who met the inclusion criteria of the study. After measuring the flexibility of hamstring muscle, strength was measured by 1RM for the same side (right hamstring muscle. Static Stretching Protocol was given for 5 days per week for 6 weeks to all the participants. After the 6 weeks of training, knee extension deficiency and 1RM was documented. Result: Statistical analysis using Paired t-test was done. The t-test showed that there was significant effect of static stretching on 1RM of hamstring muscle (p<0.05 & active knee extension test (p=0.000. Conclusion: Static stretching showed significant change in pre and post 1RM of hamstring muscle and active knee extension test. There was significant improvement of hamstring muscles flexibility and strength after giving static stretching in female population. So it is possible that females who are unable to participate in traditional strength training activities may be able to experience gains through static stretching.

  16. Effects of right atrial stretch on plasma renin activity.

    Science.gov (United States)

    Annat, G; Grandjean, B; Vincent, M; Jarsaillon, E; Sassard, J

    1976-04-01

    In anaesthetized dog, right atrial stretch leads in the first five minutes to a decrease in plasma renin activity, when measured in inferior vena cava just above the renal veins. Bilateral cervical vagotomy increases plasma renin activity. After vagotomy, atrial stretch no longer has any effect on plasma renin activity. The results support the hypothesis of a control of renin secretion originating from atrial volume receptors.

  17. Seizmic response spectra

    Directory of Open Access Journals (Sweden)

    Igor Leššo

    2005-12-01

    Full Text Available A computation of 1D and 3D seismic motion parameters was made and the influence of input parameters on these parameters were analysed. A modelling was realised on the examples of sedimentary structures geotechnical models. This comparison provides different spectral and frequencial values and spectral accelerations. The differences in seismic response spectra are influenced not only by properties of geological structures but also by the methodics of the soil structure interaction modeling and input time history spectral composition. However, the influence of geotechnical properties of geological structures on the output results are apparent. The modelling results of different input time history spectral composition, the Ricker impuls and the Gabor function were compared. In the area of cement factory in Rohožník, the new rotary kiln furnance is planned to be build. In the sense of STN 73 0036 the expert seismic judgment has been claimed. The standard and local seismic response spectra is computed for the place where the rotary kiln will be situated. The application of the local spectral acceleration in seismic load computations enables to save costs in comparing with the standard acceleration.

  18. Communications: On artificial frequency shifts in infrared spectra obtained from centroid molecular dynamics: Quantum liquid water

    Science.gov (United States)

    Ivanov, Sergei D.; Witt, Alexander; Shiga, Motoyuki; Marx, Dominik

    2010-01-01

    Centroid molecular dynamics (CMD) is a popular method to extract approximate quantum dynamics from path integral simulations. Very recently we have shown that CMD gas phase infrared spectra exhibit significant artificial redshifts of stretching peaks, due to the so-called "curvature problem" imprinted by the effective centroid potential. Here we provide evidence that for condensed phases, and in particular for liquid water, CMD produces pronounced artificial redshifts for high-frequency vibrations such as the OH stretching band. This peculiar behavior intrinsic to the CMD method explains part of the unexpectedly large quantum redshifts of the stretching band of liquid water compared to classical frequencies, which is improved after applying a simple and rough "harmonic curvature correction."

  19. Efficacy of hamstring stretching programs in schoolchildren. A systematic review

    Directory of Open Access Journals (Sweden)

    Carlos-Alberto BECERRA FERNANDEZ

    2017-03-01

    Full Text Available The main purpose of the present review was to examine the scientific literature on the effects of physical education-based stretching programs on hamstring extensibility in schoolchildren aged 6-11 years. For this purpose relevant studies were searched from ten electronic databases dated up through May 2015. Of the 25 potentially relevant articles identified and retrieved for more detailed evaluation, only eight studies were included in the present review because they met the inclusion criteria. The overall results showed that incorporating hamstring stretching as a part of physical education classes produces a significant improvement in the scores of the tests: straight leg raise and classic sit-and-reach, for the experimental groups, but not for control groups. Stretching programs can be included in Physical Education classes, specifically during the warm-up and the cool down periods in order to improve hamstring extensibility. Although it seems that the stretching exercises in the warm-up period could be less effective in gaining flexibility in school children. Studies that use a stretching volume between 4 and 7 minutes per session and 2-4 training classes per week, obtain statistically significant improvements on the levels of hamstring flexibility in the experimental groups. However, after a five-week detraining period, children revert back to their initial flexibility levels. Therefore, it seems appropriate that physical education teachers should implement stretching programs to improve the students´ flexibility during the Physical Education classes.

  20. Equibiaxial cyclic stretch stimulates fibroblasts to rapidly remodel fibrin.

    Science.gov (United States)

    Balestrini, Jenna Leigh; Billiar, Kristen Lawrence

    2006-01-01

    Understanding the effects of the mechanical environment on wound healing is critical for developing more effective treatments to reduce scar formation and contracture. The aim of this study was to investigate the effects of dynamic mechanical stretch on cell-mediated early wound remodeling independent of matrix alignment which obscures more subtle remodeling mechanisms. Cyclic equibiaxial stretch (16% stretch at 0.2 Hz) was applied to fibroblast-populated fibrin gel in vitro wound models for eight days. Compaction, density, tensile strength, and collagen content were quantified as functional measures of remodeling. Stretched samples were approximately ten times stronger, eight-fold more dense, and eight times thinner than statically cultured samples. These changes were accompanied by a 15% increase in net collagen but no significant differences in cell number or viability. When collagen crosslinking was inhibited in stretched samples, the extensibility increased and the strength decreased. The apparent weakening was due to a reduction in compaction rather than a decrease in ability of the tissue to withstand tensile forces. Interestingly, inhibiting collagen crosslinking had no measurable effects on the statically cultured samples. These results indicate that amplified cell-mediated compaction and even a slight addition in collagen content play substantial roles in mechanically induced wound strengthening. These findings increase our understanding of how mechanical forces guide the healing response in skin, and the methods employed in this study may also prove valuable tools for investigating stretch-induced remodeling of other planar connective tissues and for creating mechanically robust engineered tissues.

  1. Effects of Stretching Exercise on Heart Rate Variability During Pregnancy.

    Science.gov (United States)

    Logan, Jeongok G; Yeo, SeonAe

    Little evidence exists for effects of low-intensity exercises such as stretching on cardiovascular health in pregnant women. Our aim was to evaluate the effect of a 20-minute stretching exercise on heart rate variability (HRV), blood pressure (BP), and heart rate (HR) in healthy pregnant women. In 15 pregnant women with a mean (SD) age of 29.47 (4.07) years and mean (SD) gestational weeks of 26.53 (8.35), HRV, and BP were measured before and after the 20-minute stretching exercise. Compared with before the stretching exercise, standard deviation of the normal-to-normal intervals, total variability of heart rate, increased by 7.40 milliseconds (t = -2.31, P = .04) and root mean square of successive differences, a surrogate measure of parasympathetic outflow, also increased by 11.68 milliseconds (Z = -2.04, P = .04) after the stretching exercise. Diastolic BP and HR decreased by 2.13 mm Hg (t = 1.93, P = .07) and 3.31 bpm (t = 2.17, P = .05), respectively, but they did not reach statistical significance. These preliminary data suggest that 20 minutes of stretching exercise may promote cardiovascular health by attenuating the loss of parasympathetic tone associated with pregnancy.

  2. THEORETICAL INTERPRETATION OF INFRARED-SPECTRA OF N-CYCLOHEXYL-2-PYRROLIDONE IN MIXTURES OF HEXANE AND CDCL3

    NARCIS (Netherlands)

    LOOS, D; PERJESSY, A; ENGBERTS, JBFN

    The infrared spectra of N-cyclohexyl-2-pyrrolidone (NCP) in binary mixtures of hexane and CDCl3 were interpreted theoretically in the region of C=O stretching vibrations using the AMI semiempirical method. The results were compared with those obtained for N,N-dimethylacetamide (DMA), cyclohexanone

  3. [Sciatica. From stretch rack to microdiscectomy].

    Science.gov (United States)

    Gruber, P; Böni, T

    2015-12-01

    In ancient times as well as in the Middle Ages treatment options for discogenic nerve compression syndrome were limited and usually not very specific because of low anatomical and pathophysiological knowledge. The stretch rack (scamnum Hippocratis) was particularly prominent but was widely used as a therapeutic device for very different spinal disorders. Since the beginning of the nineteenth century anatomical knowledge increased and the advances in the fields of asepsis, anesthesia and surgery resulted in an increase in surgical interventions on the spine. In 1908 the first successful lumbar discectomy was initiated and performed by the German neurologist Heinrich O. Oppenheim (1858-1919) and the surgeon Fedor Krause (1857-1937); however, neither recognized the true pathological condition of discogenic nerve compression syndrome. With the landmark report in the New England Journal of Medicine in 1934, the two American surgeons William Jason Mixter (1880-1958) and Joseph Seaton Barr (1901-1963) finally clarified the pathomechanism of lumbar disc herniation and furthermore, propagated discectomy as the standard therapy. Since then interventions on intervertebral discs rapidly increased and the treatment options for lumbar disc surgery quickly evolved. The surgical procedures changed over time and were continuously being refined. In the late 1960s the surgical microscope was introduced for spinal surgery by the work of the famous neurosurgeon Mahmut Gazi Yasargil and his colleague Wolfhard Caspar and so-called microdiscectomy was introduced. Besides open discectomy other interventional techniques were developed to overcome the side effects of surgical procedures. In 1964 the American orthopedic surgeon Lyman Smith (1912-1991) introduced chemonucleolysis, a minimally invasive technique consisting only of a cannula and the proteolytic enzyme chymopapain, which is injected into the disc compartment to dissolve the displaced disc material. In 1975 the Japanese orthopedic

  4. The donor OH stretching–libration dynamics of hydrogen-bonded methanol dimers in cryogenic matrices

    DEFF Research Database (Denmark)

    Heger, M.; Andersen, J.; Suhm, M. A.

    2016-01-01

    FTIR spectra of the methanol dimer trapped in neon matrices are presented. The fundamental, overtone and combination bands involving the donor OH libration and stretching motions were observed in order to extract relevant anharmonicity constants. We find a stretching–libration coupling constant...

  5. Continuum Fitting HST QSO Spectra

    Science.gov (United States)

    Tytler, David; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    The Principal Component Analysis (PCA) method which we are using to fit and describe QSO spectra relies upon the fact that QSO continuum are generally very smooth and simple except for emission and absorption lines. To see this we need high signal-to-noise (S/N) spectra of QSOs at low redshift which have relatively few absorption lines in the Lyman-a forest. We need a large number of such spectra to use as the basis set for the PCA analysis which will find the set of principal component spectra which describe the QSO family as a whole. We have found that too few HST spectra have the required S/N and hence we need to supplement them with ground based spectra of QSOs at higher redshift. We have many such spectra and we have been working to make them suitable for this analysis. We have concentrated on this topic since 12/15/01.

  6. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

    LENUS (Irish Health Repository)

    O'Sullivan, Kieran

    2009-01-01

    BACKGROUND: Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. METHODS: A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. RESULTS: Across both groups, there was a significant main effect for time (p < 0.001). PKE ROM significantly increased with warm-up (p < 0.001). From warm-up, PKE ROM further increased with static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p < 0.001) after 15 minutes of rest, but remained significantly greater than at baseline (p < 0.001). Between groups, there was no main effect for group (p = 0.462), with no difference in mean PKE ROM values at any individual stage of the protocol (p > 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). CONCLUSION: Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced

  7. EFFECTIVENESS OF PNF STRETCHING VERSUS STATIC STRETCHING ON PAIN AND HAMSTRING FLEXIBILITY FOLLOWING MOIST HEAT IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

    OpenAIRE

    Meena .V; Shanthi .C; Madhavi .K

    2016-01-01

    Background: Osteoarthritis (OA) is a degenerative joint disease and one of the major public health problem that causesfunctional impairment and reduced quality of life. To compare the effectiveness of PNF Hold relax stretching versus Static stretching on pain and flexibility of hamstring following moist heat in individuals with knee osteoarthritis. Hamstring tightness is the major problem in knee osteoarthritis individuals. Therefore the need of study is comparing the effectiveness of PNF Hol...

  8. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

    Directory of Open Access Journals (Sweden)

    Murray Elaine

    2009-04-01

    Full Text Available Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM. 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1 at baseline; (2 after warm-up; (3 after stretch (static or dynamic and (4 after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Results Across both groups, there was a significant main effect for time (p 0.05. Using ANCOVA to adjust for the non-significant (p = 0.141 baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05. Conclusion Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. Trial Registration ACTRN12608000638336

  9. Cardiovascular Responses to Skeletal Muscle Stretching: "Stretching" the Truth or a New Exercise Paradigm for Cardiovascular Medicine?

    Science.gov (United States)

    Kruse, Nicholas T; Scheuermann, Barry W

    2017-12-01

    Stretching is commonly prescribed with the intended purpose of increasing range of motion, enhancing muscular coordination, and preventing prolonged immobilization induced by aging or a sedentary lifestyle. Emerging evidence suggests that acute or long-term stretching exercise may modulate a variety of cardiovascular responses. Specifically, at the onset of stretch, the mechanical deformation of the vascular bed coupled with stimulation of group III muscle afferent fibers initiates a cascade of events resulting in both peripheral vasodilation and a heart rate-driven increase in cardiac output, blood pressure, and muscle blood flow. This potential to increase shear stress and blood flow without the use of excessive muscle energy expenditure may hold important implications for future therapeutic vascular medicine and cardiac health. However, the idea that a cardiovascular component may be involved in human skeletal muscle stretching is relatively new. Therefore, the primary intent of this review is to highlight topics related to skeletal muscle stretching and cardiovascular regulation and function. The current evidence suggests that acute stretching causes a significant macro- and microcirculatory event that alters blood flow and the relationship between oxygen availability and oxygen utilization. These acute vascular changes if performed chronically may result in improved endothelial function, improved arterial blood vessel stiffness, and/or reduced blood pressure. Although several mechanisms have been postulated, an increased nitric oxide bioavailability has been highlighted as one promising candidate for the improvement in vessel function with stretching. Collectively, the evidence provided in this review suggests that stretching acutely or long term may serve as a novel and alternative low intensity therapeutic intervention capable of improving several parameters of vascular function.

  10. Vibrational dephasing of the C-Br stretching modes in gauche and trans dibromoethane

    Science.gov (United States)

    Schwartz, M.; Moradi-Araghi, A.; Koehler, W. H.

    The isotropic Raman spectra of the gauche and trans C-Br stretching modes in 1,2-dibromoethane were studied as a function of temperature in the liquid phase. Isotropic dephasing times were found to be longer for the gauche conformer, and decreased at higher temperatures for both rotamers. Vibrational second moments were observed to be greater for the trans species. Application of the isolated binary collision model to this system could not reproduce the experimentally observed temperature dependence of τiso. Values of the modulation times obtained from the Kubo lineshape formalism are in qualitative agreement with Enskog hard-sphere collision times. This approach was also used to provide a qualitative explanation of the longer observed modulation times in the gauche conformer.

  11. Effects of Static Stretching and Playing Soccer on Knee Laxity.

    Science.gov (United States)

    Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W; Freiwald, Jürgen

    2015-11-01

    This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Randomized controlled trial. University biomechanics laboratory. Thirty-one athletes were randomly assigned into a stretching (26.9 ± 6.2 years, 1.77 ± 0.09 m, 67.9 ± 10.7 kg) and a control group (27.9 ± 7.4 years, 1.75 ± 0.08 m, 72.0 ± 14.9 kg). Thirty-one amateur soccer players in an additional soccer group (25.1 ± 5.6 years, 1.74 ± 0.10 m, 71.8 ± 14.8 kg). All participants had no history of knee injury requiring surgery and any previous knee ligament or cartilage injury. The stretching group performed 4 different static stretching exercises with a duration of 2 × 20 seconds interspersed with breaks of 10 seconds. The soccer group completed a 90-minute soccer-specific training program. The control group did not perform any physical activity for approximately 30 minutes. Anterior tibial translation was measured with the KT-1000 knee arthrometer at forces of 67 N, 89 N, and maximal manual force (Max) before and after the intervention. There was a significant increase in ATT after static stretching and playing soccer at all applied forces. Maximal manual testing revealed a mean increase of ATT after static stretching of 2.1 ± 1.6 mm (P static stretching at 67 and 89 N is significantly higher than in controls. At maximum manual testing, significant differences were evident between all groups. Static stretching and playing soccer increase ATT and may consequently influence mechanical factors of the anterior cruciate ligament. The ATT increase after static stretching was greater than after playing soccer. The observed increase in ATT after static stretching and playing soccer may be associated with changes in kinesthetic perception and sensorimotor control, activation of muscles, joint stability, overall performance, and higher injury risk.

  12. INFRARED SPECTRA, THERMOGRAVIMETRIC ANALYSIS AND ...

    African Journals Online (AJOL)

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    methyl- quinazolinone in coordination and the formation of a bond between the oxygen of L with the central metal ions, and that nitrogen atom was not the donor atom. For. [Cu(CH3COO)2(L)3]⋅2H2O complex the stretching asymmetric (νas) of ...

  13. Neural effects of muscle stretching on the spinal reflexes in multiple lower-limb muscles.

    Science.gov (United States)

    Masugi, Yohei; Obata, Hiroki; Inoue, Daisuke; Kawashima, Noritaka; Nakazawa, Kimitaka

    2017-01-01

    While previous studies have shown that muscle stretching suppresses monosynaptic spinal reflex excitability in stretched muscles, its effects on non-stretched muscles is still largely unknown. The purpose of this study was to examine the effects of muscle stretching on monosynaptic spinal reflex in non-stretched muscles. Ten healthy male subjects participated in this study. Muscle stretching of the right triceps surae muscle was performed using a motor torque device for 1 minute. Three different dorsiflexion torques (at approximately 5, 10, and 15 Nm) were applied during muscle stretching. Spinal reflexes evoked by transcutaneous spinal cord stimulation were recorded in both the lower-limb muscles before, during, and at 0 and 5 min following muscle stretching. The amplitudes of the spinal reflexes in both the stretched and non-stretched muscles in the right (ipsilateral) leg were smaller during stretching compared to before, and at 0 and 5 min after stretching. Furthermore, the degree of reduction in the amplitude of the spinal reflexes in the right (ipsilateral) leg muscles increased significantly as the dorsiflexion torque (i.e., stretching of the right triceps surae muscles) increased. In contrast, reduction in the amplitude of the spinal reflexes with increasing dorsiflexion torque was not seen in the left (contralateral) leg muscles. Our results clearly indicate that muscle stretching has inhibitory effects on monosynaptic spinal reflexes, not only in stretched muscles, but also in non-stretched muscles of the ipsilateral leg.

  14. Overtone vibrational spectroscopy in H2-H2O complexes: a combined high level theoretical ab initio, dynamical and experimental study.

    Science.gov (United States)

    Ziemkiewicz, Michael P; Pluetzer, Christian; Nesbitt, David J; Scribano, Yohann; Faure, Alexandre; van der Avoird, Ad

    2012-08-28

    First results are reported on overtone (v(OH) = 2 ← 0) spectroscopy of weakly bound H(2)-H(2)O complexes in a slit supersonic jet, based on a novel combination of (i) vibrationally mediated predissociation of H(2)-H(2)O, followed by (ii) UV photodissociation of the resulting H(2)O, and (iii) UV laser induced fluorescence on the nascent OH radical. In addition, intermolecular dynamical calculations are performed in full 5D on the recent ab initio intermolecular potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)] in order to further elucidate the identity of the infrared transitions detected. Excellent agreement is achieved between experimental and theoretical spectral predictions for the most strongly bound van der Waals complex consisting of ortho (I = 1) H(2) and ortho (I = 1) H(2)O (oH(2)-oH(2)O). Specifically, two distinct bands are seen in the oH(2)-oH(2)O spectrum, corresponding to internal rotor states in the upper vibrational manifold of Σ and Π rotational character. However, none of the three other possible nuclear spin modifications (pH(2)-oH(2)O, pH(2)-pH(2)O, or oH(2)-pH(2)O) are observed above current signal to noise level, which for the pH(2) complexes is argued to arise from displacement by oH(2) in the expansion mixture to preferentially form the more strongly bound species. Direct measurement of oH(2)-oH(2)O vibrational predissociation in the time domain reveals lifetimes of 15(2) ns and <5(2) ns for the Σ and Π states, respectively. Theoretical calculations permit the results to be interpreted in terms of near resonant energy levels and intermolecular alignment of the H(2) and H(2)O wavefunctions, providing insight into predissociation dynamical pathways from these metastable levels.

  15. Tropine forming tropinone reductase gene from Withania somnifera (Ashwagandha: biochemical characteristics of the recombinant enzyme and novel physiological overtones of tissue-wide gene expression patterns.

    Directory of Open Access Journals (Sweden)

    Amit Kumar Kushwaha

    expression profiles are discussed with respect to their physiological overtones.

  16. Human Development XIII: The Connection Between the Structure of the Overtone System and the Tone Language of Music. Some Implications for Our Understanding of the Human Brain

    Directory of Open Access Journals (Sweden)

    Søren Ventegodt

    2008-01-01

    Full Text Available The functioning brain behaves like one highly-structured, coherent, informational field. It can be popularly described as a “coherent ball of energy”, making the idea of a local highly-structured quantum field that carries the consciousness very appealing. If that is so, the structure of the experience of music might be a quite unique window into a hidden quantum reality of the brain, and even of life itself. The structure of music is then a mirror of a much more complex, but similar, structure of the energetic field of the working brain. This paper discusses how the perception of music is organized in the human brain with respect to the known tone scales of major and minor. The patterns used by the brain seem to be similar to the overtones of vibrating matter, giving a positive experience of harmonies in major. However, we also like the minor scale, which can explain brain patterns as fractal-like, giving a symmetric “downward reflection” of the major scale into the minor scale. We analyze the implication of beautiful and ugly tones and harmonies for the model. We conclude that when it comes to simple perception of harmonies, the most simple is the most beautiful and the most complex is the most ugly, but in music, even the most disharmonic harmony can be beautiful, if experienced as a part of a dynamic release of musical tension. This can be taken as a general metaphor of painful, yet meaningful, and developing experiences in human life.

  17. Tropine Forming Tropinone Reductase Gene from Withania somnifera (Ashwagandha): Biochemical Characteristics of the Recombinant Enzyme and Novel Physiological Overtones of Tissue-Wide Gene Expression Patterns

    Science.gov (United States)

    Kushwaha, Amit Kumar; Sangwan, Neelam Singh; Trivedi, Prabodh Kumar; Negi, Arvind Singh; Misra, Laxminarain; Sangwan, Rajender Singh

    2013-01-01

    profiles are discussed with respect to their physiological overtones. PMID:24086372

  18. Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments

    Directory of Open Access Journals (Sweden)

    Arthur Leloup

    2017-10-01

    Full Text Available Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10% than muscular arteries (2%. As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC. The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α1-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor and/or 35 μM diltiazem (blocker of voltage-gated Ca2+ channels were measured. As compared with static or cyclic stretch at low amplitude (<10 mN or low frequency (0.1 Hz, cyclic stretch at physiological amplitude (>10 mN and frequency (1–10 Hz caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME, physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca2+ and shifted the smaller tonic contraction more from a voltage-gated Ca2+ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and

  19. Measurement of skin stretch using digital image speckle correlation.

    Science.gov (United States)

    Staloff, Isabelle Afriat; Rafailovitch, Miriam

    2008-08-01

    The surface of the skin is covered by intersecting grooves and ridges which produce characteristic skin surface patterns. It has been suggested that these folds provide a reserve of tissue, allowing the skin to stretch during normal muscle movements. More so, skin is anisotropic and under constant tension. Therefore, to characterize skin displacement following stretch, a discrete, description of the in-plane skin displacement during stretch is of interest. We introduce the use of digital image speckle correlation (DISC), a non-contact technique, to map, in two dimensions, the surface deformation patterns resulting from skin stretching. We analyze skin stretch under the mechanical action of a film former applied on a defined square surface on the back of the hand. This is achieved by taking a series of images, during the drying process of the film former. The images are then analyzed with DISC to create vector diagram and projection maps, from which we can obtain spatially resolved information regarding the skin displacement. We first show that DISC can provide spatially resolved information at any time point during the drying process: areas of de-wetting, wetting were identified using projection maps; we then extracted the value of the drying time. Finally using a vector map, we show the orientation of the skin displacement during stretching and calculated the magnitude of the total stretch. We have shown previously that DISC can be used to determine skin mechanical properties and muscular activity. We show here that DISC, as a non-contact technique, can map, in two dimensions, the surface deformation patterns of a polymer solution on a substrate at any time point during the drying process. DISC analysis generates for each speckle of the sample analyzed, the orientation and magnitude of displacement of the polymer solution. DISC can map in two dimensions the deformation undergone by the substrate and skin stretch is measured in this particular case. We therefore

  20. Extracting local stretching from left ventricle angiography data

    Science.gov (United States)

    Mishra, Sanjoy K.; Goldgof, Dmitry B.

    1991-07-01

    This paper presents a new method for extracting local surface stretching from the left ventricle (LV) cineangiography data. The algorithm is based on Gaussian curvature for surface stretching recovery under more realistic conformal motion assumption. During conformal motion surface stretching can vary over the surface patch. In particular, surface stretching can be approximated using linear or quadratic (or higher order) functions. Then, coefficients of the approximating function can be calculated and surface stretching computed from changes in surface curvature at corresponding points. For example, linear approximation requires three point correspondences (between consecutive time frames) within small surface patch. The authors demonstrate the higher precision of the new approach (as compared to homothetic assumption in the authors' earlier work) on simulated and real data of the left ventricle of the human heart. The data set was provided by Dr. Alistair Young of the University of Auckland, New Zealand, and consists of the tracked locations of eleven bifurcation points of the left coronary artery and the tracked locations of 292 vessel points for one cardiac cycle (60 frames/cycle).

  1. Controlled cyclic stretch bioreactor for tissue-engineered heart valves.

    Science.gov (United States)

    Syedain, Zeeshan H; Tranquillo, Robert T

    2009-09-01

    A tissue-engineered heart valve (TEHV) represents the ultimate valve replacement, especially for juvenile patients given its growth potential. To date, most TEHV bioreactors have been developed based on pulsed flow of culture medium through the valve lumen to induce strain in the leaflets. Using a strategy for controlled cyclic stretching of tubular constructs reported previously, we developed a controlled cyclic stretch bioreactor for TEHVs that leads to improved tensile and compositional properties. The TEHV is mounted inside a latex tube, which is then cyclically pressurized with culture medium. The root and leaflets stretch commensurately with the latex, the stretching being dictated by the stiffer latex and thus controllable. Medium is also perfused through the lumen at a slow rate in a flow loop to provide nutrient delivery. Fibrin-based TEHVs prepared with human dermal fibroblasts were subjected to three weeks of cyclic stretching with incrementally increasing strain amplitude. The TEHV possessed the tensile stiffness and stiffness anisotropy of leaflets from sheep pulmonary valves and could withstand cyclic pulmonary pressures with similar distension as for a sheep pulmonary artery.

  2. Influence of chronic stretching on muscle performance: Systematic review.

    Science.gov (United States)

    Medeiros, D M; Lima, C S

    2017-08-01

    The aim of the current study was to investigate the influence of chronic stretching on muscle performance (MP) by a systematic review. The search strategy included MEDLINE, PEDro, Cochrane CENTRAL, LILACS, and manual search from inception to June 2016. Randomized and controlled clinical trials, non-randomized, and single group studies that have analyzed the influence of flexibility training (FT) (using any stretching technique) on MP were included. Differently, studies with special populations (children, elderly, and people with any dysfunction/disease), and articles that have used FT protocols shorter than three weeks or 12 sessions were excluded. The MP assessment could have been performed by functional tests (e.g. jump, sprint, stretch-shortening cycle tasks), isometric contractions, and/or isotonic contractions. Twenty-eight studies were included out of 513. Seven studies evaluated MP by stretch-shortening cycle tasks, Ten studies evaluated MP by isometric contractions, and 13 studies assessed MP by isotonic contractions. We were unable to perform a meta-analysis due to the high heterogeneity among the included studies. In an individual study level analysis, we identified that 14 studies found positive effects of chronic stretching on MP. The improvements were observed only in functional tests and isotonic contractions, isometric contractions were not affected by FT. Therefore, FT might have an influence on dynamic MP. However, more studies are necessary to confirm whether FT can positively affect MP. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Design energy spectra for Turkey

    OpenAIRE

    López Almansa, Francisco; Yazgan, Ahmet Utku; Benavent Climent, Amadeo

    2012-01-01

    This work proposes design energy spectra in terms of velocity, derived through linear dynamic analyses on Turkish registers and intended for regions with design peak acceleration 0.3 g or higher. In the long and mid period ranges the analyses are linear, taking profit of the rather insensitivity of the spectra to the structural parameters other than the fundamental period; in the short period range, the spectra are more sensitive to the structural parameters and nonlinear analyses would be re...

  4. Investigating the role of musical genre in human perception of music stretching resistance

    OpenAIRE

    Chen, Jun; Wang, Chaokun

    2017-01-01

    To stretch a music piece to a given length is a common demand in people's daily lives, e.g., in audio-video synchronization and animation production. However, it is not always guaranteed that the stretched music piece is acceptable for general audience since music stretching suffers from people's perceptual artefacts. Over-stretching a music piece will make it uncomfortable for human psychoacoustic hearing. The research on music stretching resistance attempts to estimate the maximum stretchab...

  5. Sequencing BPS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Gukov, Sergei [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Max-Planck-Institut für Mathematik,Vivatsgasse 7, D-53111 Bonn (Germany); Nawata, Satoshi [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Centre for Quantum Geometry of Moduli Spaces, University of Aarhus,Nordre Ringgade 1, DK-8000 (Denmark); Saberi, Ingmar [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Stošić, Marko [CAMGSD, Departamento de Matemática, Instituto Superior Técnico,Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Mathematical Institute SANU,Knez Mihajlova 36, 11000 Belgrade (Serbia); Sułkowski, Piotr [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warsaw (Poland)

    2016-03-02

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel “sliding” property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d N=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.

  6. Dynamic Contractility and Efficiency Impairments in Stretch-Shortening Cycle Are Stretch-Load-Dependent After Training-Induced Muscle Damage

    NARCIS (Netherlands)

    Vaczi, Mark; Racz, Levente; Hortobagyi, Tibor; Tihanyi, Jozsef

    Vaczi, M, Racz, L, Hortobagyi, T, and Tihanyi, J. Dynamic contractility and efficiency impairments in stretch-shortening cycle are stretch-load-dependent after training-induced muscle damage. J Strength Cond Res 27(8): 2171-2179, 2013To determine the acute task and stretch-load dependency of

  7. Tail modeling in a stretched magnetosphere. I - Methods and transformations

    Science.gov (United States)

    Stern, David P.

    1987-01-01

    A new method is developed for representing the magnetospheric field B as a distorted dipole field. Because Delta-B = 0 must be maintained, such a distortion may be viewed as a transformation of the vector potential A. The simplest form is a one-dimensional 'stretch transformation' along the x axis, concisely represented by the 'stretch function' f(x), which is also a convenient tool for representing features of the substorm cycle. One-dimensional stretch transformations are extended to spherical, cylindrical, and parabolic coordinates and then to arbitrary coordinates. It is shown that distortion transformations can be viewed as mappings of field lines from one pattern to another; the final result only requires knowledge of the field and not of the potentials. General transformations in Cartesian and arbitrary coordinates are derived, and applications to field modeling, field line motion, MHD modeling, and incompressible fluid dynamics are considered.

  8. Alignment of Disks with Lagrangian Stretching in Turbulence

    Science.gov (United States)

    Hunt, Conor; Tierney, Lydia; Kramel, Stefan; Voth, Greg

    2015-11-01

    We study Lagrangian stretching in isotropic turbulence in order to understand both the rotations of disks and the preferential alignment of vorticity with the intermediate strain rate eigenvector. Using velocity gradient tensors from a numerical simulation of homogeneous isotropic turbulence at Rλ = 180, we calculate the Cauchy-Green strain tensors whose eigenvectors provide a natural basis for studying stretching phenomenon. Previous work has shown that rods preferentially align with the vorticity as a result of both quantities independently aligning with the extensional Cauchy-Green eigenvector. In contrast, disks orient with their symmetry axis perpendicular to vorticity and preferentially align with the compressional Cauchy-Green eigenvector. We also find that the intermediate strain rate eigenvector is aligned with the extensional Cauchy-Green eigenvector. A natural consequence is that the intermediate strain rate eigenvector is aligned with the vorticity vector since conservation of angular momentum aligns vorticity with the direction it has been stretched.

  9. Stretching of red blood cells at high strain rates

    Science.gov (United States)

    Mancuso, J. E.; Ristenpart, W. D.

    2017-10-01

    Most work on the mechanical behavior of red blood cells (RBCs) in flow has focused on simple shear flows. Relatively little work has examined RBC deformations in the physiologically important extensional flow that occurs at the entrance to a constriction. In particular, previous work suggests that RBCs rapidly stretch out and then retract upon entering the constriction, but to date no model predicts this behavior for the extremely high strain rates typically experienced there. In this Rapid Communication, we use high speed video to perform systematic measurements of the dynamic stretching behavior of RBCs as they enter a microfluidic constriction. We demonstrate that both the Kelvin-Voigt and Skalak viscoelastic models capture the observed stretching dynamics, up to strain rates as high as 2000 s-1. The results indicate that the effective elastic modulus of the RBC membrane at these strain rates is an order of magnitude larger than moduli measured by micropipette aspiration or other low strain rate techniques.

  10. Effects of static stretching on 1-mile uphill run performance.

    Science.gov (United States)

    Lowery, Ryan P; Joy, Jordan M; Brown, Lee E; Oliveira de Souza, Eduardo; Wistocki, David R; Davis, Gregory S; Naimo, Marshall A; Zito, Gina A; Wilson, Jacob M

    2014-01-01

    It is previously demonstrated that static stretching was associated with a decrease in running economy and distance run during a 30-minute time trial in trained runners. Recently, the detrimental effects of static stretching on economy were found to be limited to the first few minutes of an endurance bout. However, economy remains to be studied for its direct effects on performance during shorter endurance events. The aim of this study was to investigate the effects of static stretching on 1-mile uphill run performance, electromyography (EMG), ground contact time (GCT), and flexibility. Ten trained male distance runners aged 24 ± 5 years with an average VO2max of 64.9 ± 6.5 mL·kg-1·min-1 were recruited. Subjects reported to the laboratory on 3 separate days interspersed by 72 hours. On day 1, anthropometrics and V[Combining Dot Above]O2max were determined on a motor-driven treadmill. On days 2 and 3, subjects performed a 5-minute treadmill warm-up and either performed a series of 6 lower-body stretches for three 30-second repetitions or sat still for 10 minutes. Time to complete a 1-mile run under stretching and nonstretching conditions took place in randomized order. For the performance run, subjects were instructed to run as fast as possible at a set incline of 5% until a distance of 1 mile was completed. Flexibility from the sit and reach test, EMG, GCT, and performance, determined by time to complete the 1-mile run, were recorded after each condition. Time to complete the run was significantly less (6:51 ± 0:28 minutes) in the nonstretching condition as compared with the stretching condition (7:04 ± 0:32 minutes). A significant condition-by-time interaction for muscle activation existed, with no change in the nonstretching condition (pre 91.3 ± 11.6 mV to post 92.2 ± 12.9 mV) but increased in the stretching condition (pre 91.0 ± 11.6 mV to post 105.3 ± 12.9 mV). A significant condition-by-time interaction for GCT was also present, with no changes in

  11. Directional Cell Migration in Response to Repeated Substratum Stretching

    Science.gov (United States)

    Okimura, Chika; Iwadate, Yoshiaki

    2017-10-01

    Crawling migration plays an essential role in a variety of biological phenomena, including development, wound healing, and immune system function. Migration properties such as anterior-posterior polarity, directionality, and velocity are regulated not only by the reception of a chemoattractant but also by sensing mechanical inputs from the external environment. In this review, we describe the mechanical response of migrating cells, particularly under repeated stretching of the elastic substratum, highlighting the fact that there appear to be two independent mechanosensing systems that generate the polarity needed for migration. Cells that have no stress fibers, such as Dictyostelium cells and neutrophil-like differentiated HL-60 cells, migrate perpendicular to the stretching direction via myosin II localization. Cells that do possess stress fibers, however, such as fish keratocytes, migrate parallel to the stretching via a stress-fiber-dependent process.

  12. Short Term Effects of Neurodynamic Stretching and Static Stretching Techniques on Hamstring Muscle Flexibility in Healthy Male Subjects

    Directory of Open Access Journals (Sweden)

    Adel Rashad Ahmed

    2016-05-01

    Full Text Available Flexibility is a key component of rehabilitation and inadequate muscle extensibility remains a commonly accepted factor for musculoskeletal disorders. Studies on the most optimal technique for improving muscle flexibility are a widely debated. The aim of the study was to compare the effectiveness of neurodynamic and static stretching techniques on hamstring flexibility in healthy male subjects. This study was a randomized experimental trial; forty healthy male subjects with hamstring tightness were randomly divided into two equal groups: The neurodynamic group and the static stretching group. Treatment was given for 5 consecutive days and the outcomes were measured using Active knee Extension Test and Straight Leg Raising. There was a significant improvement in hamstring flexibility following application of both neurodynamic and static stretching but the improvement in the neurodynamic group (p<0.001 was better than that of the static group (p<0.02. Results suggest that a neurodynamic stretching could increase hamstring flexibility to a greater extent than static stretching in healthy male subjects with a tight hamstring.

  13. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

    Science.gov (United States)

    Sloot, Lizeth H; van den Noort, Josien C; van der Krogt, Marjolein M; Bruijn, Sjoerd M; Harlaar, Jaap

    2015-01-01

    Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms). Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally measure reflexes during

  14. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

    Directory of Open Access Journals (Sweden)

    Lizeth H Sloot

    Full Text Available Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms. Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally

  15. Stretching, twisting and supercoiling in short, single DNA molecules

    Science.gov (United States)

    Lam, Pui-Man; Zhen, Yi

    2018-02-01

    We had combined the Neukirch-Marko model that describes the extension, torque and supercoiling in single, stretched and twisted DNA of infinite contour length, with a form of the free energy suggested by Sinha and Samuels to describe short DNA, with contour length only a few times the persistence length. We find that the free energy of the stretched but untwisted DNA, is significantly modified from its infinitely length value and this in turn modifies significantly the torque and supercoiling. We show that this is consistent with short DNA being more flexible than infinitely long DNA. We hope our results will stimulate experimental investigation of torque and supercoiling in short DNA.

  16. Cell volume and membrane stretch independently control K+ channel activity

    DEFF Research Database (Denmark)

    Bomholtz, Sofia Hammami; Willumsen, Niels J; Olsen, Hervør L

    2009-01-01

    A number of potassium channels including members of the KCNQ family and the Ca(2+) activated IK and SK, but not BK, are strongly and reversibly regulated by small changes in cell volume. It has been argued that this general regulation is mediated through sensitivity to changes in membrane stretch....... To test this hypothesis we have studied the regulation of KCNQ1 and BK channels after expression in Xenopus oocytes. Results from cell-attached patch clamp studies (approximately 50 microm(2) macropatches) in oocytes expressing BK channels demonstrate that the macroscopic volume-insensitive BK current...... that stretch and volume sensitivity can be considered two independent regulatory mechanisms....

  17. Management of stretch marks (with a focus on striae rubrae

    Directory of Open Access Journals (Sweden)

    Uwe Wollina

    2017-01-01

    Full Text Available Stretch marks are one of the most common benign cutaneous lesions and encountered esthetic problems. Striae rubrae and striae albae can be differentiated on the basis of clinical appearance. Histologically, disturbances of the dermal fiber network and local expression of receptors for sexual steroids have been detected. The epidermal changes are secondary. Prevention of stretch marks using topical ointments and oils is debatable. Treatment of striae rubrae by lasers and light devices improves appearance. Microneedling and non-ablative and fractionated lasers have been used. This review provides an overview on current treatment options with a special focus on laser treatments.

  18. Fluorescence Spectra of Blowfly Metaxanthopsins

    NARCIS (Netherlands)

    Kruizinga, B.; Stavenga, D.G.

    The main visual pigment of blowflies (xanthopsin) photoconverts into two thermostable metaxanthopsin states M and M’. The fluorescence spectra of the two photoproducts were studied by microspectrofluorometry in vivo. The emission spectra of M and M’ are very similar and peak at 660 nm. The

  19. Fluorescence Spectra of Highlighter Inks

    Science.gov (United States)

    Birriel, Jennifer J.; King, Damon

    2018-01-01

    Fluorescence spectra excited by laser pointers have been the subject of several papers in TPT. These papers all describe a fluorescence phenomenon in which the reflected laser light undergoes a change in color: this color change results from the combination of some partially reflected laser light and additional colors generated by fluorescent emission. Here we examine the fluorescence spectra of highlighter inks using green and violet laser pointers. We use an RSpec Explorer spectrometer to obtain spectra and compare the emission spectra of blue, green, yellow, orange, pink, and purple highlighters. The website Compound Interest details the chemical composition of highlighter inks; in addition, the site discusses how some base dye colors can be combined to produce the variety commercially available colors. Spectra obtained in this study were qualitatively consistent with the Compound Interest site. We discuss similarities and differences between various highlighter colors and conclude with the relevance of such studies to physics students.

  20. Stretching to prevent or reduce muscle soreness after exercise.

    Science.gov (United States)

    Herbert, Robert D; de Noronha, Marcos; Kamper, Steven J

    2011-07-06

    Many people stretch before or after engaging in athletic activity. Usually the purpose is to reduce risk of injury, reduce soreness after exercise, or enhance athletic performance. This is an update of a Cochrane review first published in 2007. The aim of this review was to determine effects of stretching before or after exercise on the development of delayed-onset muscle soreness. We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (to 10 August 2009), the Cochrane Central Register of Controlled Trials (2010, Issue 1), MEDLINE (1966 to 8th February 2010), EMBASE (1988 to 8th February 2010), CINAHL (1982 to 23rd February 2010), SPORTDiscus (1949 to 8th February 2010), PEDro (to 15th February 2010) and reference lists of articles. Eligible studies were randomised or quasi-randomised studies of any pre-exercise or post-exercise stretching technique designed to prevent or treat delayed-onset muscle soreness (DOMS). For the studies to be included, the stretching had to be conducted soon before or soon after exercise and muscle soreness had to be assessed. Risk of bias was assessed using The Cochrane Collaboration's 'Risk of bias' tool and quality of evidence was assessed using GRADE. Estimates of effects of stretching were converted to a common 100-point scale. Outcomes were pooled in fixed-effect meta-analyses. Twelve studies were included in the review. This update incorporated two new studies. One of the new trials was a large field-based trial that included 2377 participants, 1220 of whom were allocated stretching. All other 11 studies were small, with between 10 and 30 participants receiving the stretch condition. Ten studies were laboratory-based and other two were field-based. All studies were exposed to either a moderate or high risk of bias. The quality of evidence was low to moderate.There was a high degree of consistency of results across studies. The pooled estimate showed that pre-exercise stretching reduced soreness at one

  1. Effects on hamstring muscle extensibility, muscle activity, and balance of different stretching techniques.

    Science.gov (United States)

    Lim, Kyoung-Il; Nam, Hyung-Chun; Jung, Kyoung-Sim

    2014-02-01

    [Purpose] The purpose of this study was to investigate the effects of two different stretching techniques on range of motion (ROM), muscle activation, and balance. [Subjects] For the present study, 48 adults with hamstring muscle tightness were recruited and randomly divided into three groups: a static stretching group (n=16), a PNF stretching group (n=16), a control group (n=16). [Methods] Both of the stretching techniques were applied to the hamstring once. Active knee extension angle, muscle activation during maximum voluntary isometric contraction (MVC), and static balance were measured before and after the application of each stretching technique. [Results] Both the static stretching and the PNF stretching groups showed significant increases in knee extension angle compared to the control group. However, there were no significant differences in muscle activation or balance between the groups. [Conclusion] Static stretching and PNF stretching techniques improved ROM without decrease in muscle activation, but neither of them exerted statistically significant effects on balance.

  2. 1-D Imaging of the Dynamical Atmosphere of the Red Supergiant Betelgeuse in the CO First Overtone Lines with VLTI/AMBER

    Science.gov (United States)

    Ohnaka, K.

    2014-09-01

    We present high-spatial and high-spectral resolution observations of the red supergiant Betelgeuse in the CO first overtone lines near 2.3μm with the AMBER instrument at the Very Large Telescope Interferometer (VLTI). Our AMBER observations in 2008 spatially resolved the gas motions in a stellar atmosphere (photosphere and extended molecular outer atmosphere) for the first time other than the Sun. From our second observations one year later, we have reconstructed 1-D images in the individual CO lines with an angular resolution of 9.8 mas and a spectral resolution of 6000 by applying the self-calibration technique to restore the Fourier phase from the differential phase measurements. The reconstructed 1-D images reveal that the star appears different in the blue and red wing of the individual CO lines. In the blue wing, the star shows a pronounced, asymmetrically extended component at least up to 1.3 R⋆, while such a component does not appear in the red wing 1-D image. This can be explained by a model in which the CO gas patch (or clump) more than half as large as the star is moving slightly outward with 0-5 km s-1, while the gas in the remaining region is infalling fast with 20-30 km s-1. Comparison between the CO line data taken in 2008 and 2009 shows a significant time variation in the dynamics of the photosphere and outer atmosphere. However, the 1-D images in the continuum show only a slight deviation from a limb-darkened disk with an angular diameter of 42.49±0.06 mas, which leads to an effective temperature of 3690± 54 K. Moreover, the continuum data taken in 2008 and 2009 reveal no or only marginal time variations, much smaller than the maximum variation predicted by the current 3-D convection simulation. The derived continuum diameter also shows that the near-IR size of Betelgeuse has been nearly constant over the last 18 years, in marked contrast to the recently reported noticeable decrease in the mid-IR size.

  3. Investigating light curve modulation via kernel smoothing. I. Application to 53 fundamental mode and first-overtone Cepheids in the LMC

    Science.gov (United States)

    Süveges, Maria; Anderson, Richard I.

    2018-03-01

    Context. Recent studies have revealed a hitherto unknown complexity of Cepheid pulsations by discovering irregular modulated variability using photometry, radial velocities, and interferometry. Aim. We aim to perform a statistically rigorous search and characterization of such phenomena in continuous time, applying it to 53 classical Cepheids from the OGLE-III catalog. Methods: We have used local kernel regression to search for both period and amplitude modulations simultaneously in continuous time and to investigate their detectability. We determined confidence intervals using parametric and non-parametric bootstrap sampling to estimate significance, and investigated multi-periodicity using a modified pre-whitening approach that relies on time-dependent light curve parameters. Results: We find a wide variety of period and amplitude modulations and confirm that first overtone pulsators are less stable than fundamental mode Cepheids. Significant temporal variations in period are more frequently detected than those in amplitude. We find a range of modulation intensities, suggesting that both amplitude and period modulations are ubiquitous among Cepheids. Over the 12-year baseline offered by OGLE-III, we find that period changes are often nonlinear, sometimes cyclic, suggesting physical origins beyond secular evolution. Our method detects modulations (period and amplitude) more efficiently than conventional methods that are reliant on certain features in the Fourier spectrum, and pre-whitens time series more accurately than using constant light curve parameters, removing spurious secondary peaks effectively. Conclusions: Period and amplitude modulations appear to be ubiquitous among Cepheids. Current detectability is limited by observational cadence and photometric precision: detection of amplitude modulation below 3 mmag requires space-based facilities. Recent and ongoing space missions (K2, BRITE, MOST, CoRoT) as well as upcoming ones (TESS, PLATO) will

  4. Vibrational Coupling Pathways in the CH Stretch Region of CH_3OH and CH_3OD as Revealed by IR and Ftmw-Ir Spectroscopies

    Science.gov (United States)

    Twagirayezu, Sylvestre; Wang, Xiaoliang; Perry, David S.; Neill, Justin L.; Muckle, Matt T.; Pate, Brooks H.; Xu, Li-Hong

    2011-06-01

    Infrared spectra of jet-cooled CH_3OD and CH_3OH in the CH stretch region are observed by coherence-converted population transfer Fourier transform microwave-infrared (CCPT-FTMW-IR) spectroscopy (E torsional species only) and by slit-jet single resonance spectroscopy (both A and E torsional species, CH_3OH only). Previously, we reported the analysis of ν_3 symmetric CH stretch region (2750-2900 Cm-1), and the present work extends the analysis to higher frequency (2900-3020 Cm-1). The overall observed spectra contain 17 interacting vibrational bands for CH_3OD and 28 for CH_3OH. The signs and magnitudes of the torsional tunneling splittings are deduced for three CH fundamentals (ν_3, ν_9, ν_2) of both molecules and are compared to a model calculation and to ab initio theory. The number and distribution of observed vibrational bands indicate that the CH stretch bright states couple first to doorway states that are binary combinations of bending modes. In the parts of the spectrum where doorway states are present, the observed density of coupled states is comparable to the total density of vibrational states in the molecule, but where there are no doorway states, only the CH stretch fundamentals are observed. A time-dependent interpretation of the present FTMW-IR spectra indicates a fast (˜ 200 fs) initial decay of the bright state followed by second, slower redistribution (˜ 1-3 ps). The qualitative agreement of the present data with the time-dependent experiments of Iwaki and Dlott provides further support for the similarity of the fastest vibrational relaxation processes in the liquid and gas phases. Twagirayezu, S.; Clasp, T. N.; Perry, D. S.; Neill, J. L.; Muckle, M. T.; Pate, B. H. J. Phys. Chem. A 2010, 114, 6818 Iwaki, L. K.; Dlott, D. D. J. Phys. Chem. A 2000, 104, 9101

  5. Immediate effects of different types of stretching exercises on badminton jump smash.

    Science.gov (United States)

    Jang, Hwi S; Kim, Daeho; Park, Jihong

    2017-04-13

    Since different types of stretching exercises may alter athletic performance, we compared the effects of three types of stretching exercises on badminton jump smash. Sixteen male collegiate badminton players performed one of three different stretching exercises in a counterbalanced order on different days. Static stretching had seven typical stretches, while dynamic stretching involved nine dynamic movements, and resistance dynamic stretching was performed with weighted vests and dumbbells. Before and after each stretching exercise, subjects performed 20 trials of jump smashes. Dependent measurements were the jump heights during jump smashes, velocities of jump-smashed shuttlecocks, and drop points of jump-smashed shuttlecocks. To test the effects of each stretching exercise, we performed mixed model ANOVAs and calculated between-time effect sizes (ES). Each stretching exercise improved the jump heights during jump smashes (type main effect: F2,75= 1.19, p=0.31; static stretching: 22.1%, pstretching: 30.1%, pstretching: 17.7%, p=0.03, ES: 0.98) and velocities of jump-smashed shuttlecocks (type main effect: F2,75= 2.18, p=0.12; static stretching: 5.7%, p=0.61, ES: 0.39; dynamic stretching: 3.4%, p=0.94, ES: 0.28; resistance dynamic stretching: 6%, p=0.50, ES: 0.66). However, there were no differences among the stretching exercises for any measurement. The drop point of jump-smashed shuttlecocks did not change (interaction: F2,75= 0.88, p=0.42). All stretching exercises improved badminton jump smash performance, but we could not determine the best protocol. Since badminton requires high-speed movement and explosive force, we suggest performing dynamic stretching or resistance dynamic stretching.

  6. TERRAIN, OVERTON COUNTY, TN, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. Stretching Local Dollars: A Small Town Guide to Matching Funds.

    Science.gov (United States)

    Brown, Hamilton

    The purpose of this guidebook is to help elected leaders of small towns and communities stretch their investments when matching funds are required to compete for a grant or to pay for development costs above the grant award itself. The federal "small cities" Community Development Block Grant (CDBG) is used as an example throughout the…

  8. Measurement of Reversed Extension Flow using the Filament Stretch Rheometer

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Skov, Anne Ladegaard; Nielsen, Jens Kromann

    2008-01-01

    ). The latter is applicable on highly extensible elastomers, whereas in LAOE measurements on liquids (including polymer melts) the LAOE flow needs to be imposed upon a constant strain rate uniaxial elongation. The used Filament Stretching Rheometer allows measurements on polymeric fluids (including polymeric...... melts) from room temperature until 200 degrees C....

  9. On zero variance Monte Carlo path-stretching schemes

    International Nuclear Information System (INIS)

    Lux, I.

    1983-01-01

    A zero variance path-stretching biasing scheme proposed for a special case by Dwivedi is derived in full generality. The procedure turns out to be the generalization of the exponential transform. It is shown that the biased game can be interpreted as an analog simulation procedure, thus saving some computational effort in comparison with the corresponding nonanalog game

  10. Mediators of Yoga and Stretching for Chronic Low Back Pain

    Directory of Open Access Journals (Sweden)

    Karen J. Sherman

    2013-01-01

    Full Text Available Although yoga is an effective treatment for chronic low back pain, little is known about the mechanisms responsible for its benefits. In a trial comparing yoga to intensive stretching and self-care, we explored whether physical (hours of back exercise/week, cognitive (fear avoidance, body awareness, and self-efficacy, affective (psychological distress, perceived stress, positive states of mind, and sleep, and physiological factors (cortisol, DHEA mediated the effects of yoga or stretching on back-related dysfunction (Roland-Morris Disability Scale (RDQ. For yoga, 36% of the effect on 12-week RDQ was mediated by increased self-efficacy, 18% by sleep disturbance, 9% by hours of back exercise, and 61% by the best combination of all possible mediators (6 mediators. For stretching, 23% of the effect was mediated by increased self-efficacy, 14% by days of back exercise, and 50% by the best combination of all possible mediators (7 mediators. In open-ended questions, ≥20% of participants noted the following treatment benefits: learning new exercises (both groups, relaxation, increased awareness, and the benefits of breathing (yoga, benefits of regular practice (stretching. Although both self-efficacy and hours of back exercise were the strongest mediators for each intervention, compared to self-care, qualitative data suggest that they may exert their benefits through partially distinct mechanisms.

  11. Entropy generation in MHD flow of a uniformly stretched vertical ...

    African Journals Online (AJOL)

    This paper reports the analytical calculation of the entropy generation due to heat and mass transfer and fluid friction in steady state of a uniformly stretched vertical permeable surface with heat and mass diffusive walls, by solving analytically the mass, momentum, species concentration and energy balance equation, using ...

  12. Anharmonic bend-stretch coupling in neat liquid water

    NARCIS (Netherlands)

    Lindner, Joerg; Cringus, Dan; Pshenichnikov, Maxim S.; Voehringer, Peter

    2007-01-01

    Femtosecond mid-IR spectroscopy is used to study the vibrational relaxation dynamics in neat liquid water. By exciting the bending vibration and probing the stretching mode, it is possible to reliably determine the bending and librational lifetimes of water. The anharmonic coupling between the

  13. Effect of Mechanical Stretching of the Skin on Collagen Fibril ...

    African Journals Online (AJOL)

    Stabilization of collagen fibres during development and through growth to maturation has now become fairly documented. In vitro effect of mechanical stretching of ratsf skin on oxidative deamination of ε-NH2-groups of lysine and hydroxylysine, and functional properties of its type . collagen were studied. Experiments were ...

  14. Effects of Warm-Up Stretching Exercises on Sprint Performance

    Science.gov (United States)

    Makaruk, Hubert; Makaruk, Beata; Kedra, Stanislaw

    2008-01-01

    Study aim: To assess direct effects of warm-up consisting of static and dynamic stretching exercises on sprint results attained by students differing in sprint performance. Material and methods: A group of 24 male and 19 female physical education students, including 12 and 9 sprinters, respectively. They performed warm-ups consisting of dynamic…

  15. A Japanese Stretching Intervention Can Modify Lumbar Lordosis Curvature

    NARCIS (Netherlands)

    Kadono, Norio; Tsuchiya, Kazushi; Uematsu, Azusa; Kamoshita, Hiroshi; Kiryu, Kazunori; Hortobagyi, Tibor; Suzuki, Shuji

    Study Design: Eighteen healthy male adults were assigned to either an intervention or control group. Objectives: Isogai dynamic therapy (IDT) is one of Japanese stretching interventions and has been practiced for over 70 years. However, its scientific quantitative evidence remains unestablished. The

  16. Flow of viscous fluid along an exponentially stretching curved surface

    Directory of Open Access Journals (Sweden)

    N.F. Okechi

    Full Text Available In this paper, we present the boundary layer analysis of flow induced by rapidly stretching curved surface with exponential velocity. The governing boundary value problem is reduced into self-similar form using a new similarity transformation. The resulting equations are solved numerically using shooting and Runge-Kutta methods. The numerical results depicts that the fluid velocity as well as the skin friction coefficient increases with the surface curvature, similar trend is also observed for the pressure. The dimensionless wall shear stress defined for this problem is greater than that of a linearly stretching curved surface, but becomes comparably less for a surface stretching with a power-law velocity. In addition, the result for the plane surface is a special case of this study when the radius of curvature of the surface is sufficiently large. The numerical investigations presented in terms of the graphs are interpreted with the help of underlying physics of the fluid flow and the consequences arising from the curved geometry. Keywords: Boundary layer flow, Curved surface, Exponential stretching, Curvature

  17. Vibrations of stretched damped beams under non-ideal boundary ...

    Indian Academy of Sciences (India)

    Stretched beam vibrations; non-ideal boundary conditions; method of multiple time scales. 1. Introduction. Beams are frequently used as design models for vibration analysis. In such analysis, types of support conditions are important and have direct effect on the solutions and natural fre- quencies. Different types of supports ...

  18. Stretch Intensity vs. Inflammation: A Dose-dependent Association?

    Directory of Open Access Journals (Sweden)

    Nikos Apostolopoulos BPHE

    2015-01-01

    Full Text Available The intensity of stretching is rarely reported in scientific literature. In this study, we examined the effects of stretching intensities at 30%, 60%, and 90% of maximum range of movement (mROM on the inflammatory response of the right hamstring muscle. Methods: A randomised within-subject trial was conducted with 11 healthy recreationally active males over a three week period. Participants were strapped into an isokinetic dynamometer in the supine position, with the right knee fastened in a knee immobilizer. After randomising the ROM percentages, the hamstring muscle was moved to one of the three chosen ROM percentages for that week and held there for 5 x 60 seconds followed by a 10 second rest between repetitions. A 5ml blood sample was collected pre-, immediately post, and at 24 hours post intervention for high sensitivity C-reactive protein (hsCRP assessments. Results: Significant increases in hsCRP levels were observed between 30% mROM and 90% mROM (p=0.004 and 60% mROM and 90% mROM (p=0.034, but not between 30% and 60% (p>0.05. Conclusions: Muscle stretching at submaximal levels does not elicit a significant systemic inflammatory responses. Keywords: Stretch intensity, inflammation, hsCRP

  19. MHD flow of a uniformly stretched vertical permeable membrane in ...

    African Journals Online (AJOL)

    Journal of the Nigerian Association of Mathematical Physics ... Abstract. We present a magneto - hydrodynamic flow of a uniformly stretched vertical permeable surface undergoing Arrhenius heat reaction. ... It is also established that maximum velocity occurs in the body of the fluid close to the surface and not the surface.

  20. Contact of a spherical probe with a stretched rubber substrate

    Science.gov (United States)

    Frétigny, Christian; Chateauminois, Antoine

    2017-07-01

    We report on a theoretical and experimental investigation of the normal contact of stretched neo-Hookean substrates with rigid spherical probes. Starting from a published formulation of surface Green's function for incremental displacements on a prestretched, neo-Hookean, substrate [J. Mech. Phys. Solids 56, 2957 (2008), 10.1016/j.jmps.2008.07.002], a model is derived for both adhesive and nonadhesive contacts. The shape of the elliptical contact area together with the contact load and the contact stiffness are predicted as a function of the in-plane stretch ratios λx and λy of the substrate. The validity of this model is assessed by contact experiments carried out using an uniaxally stretched silicone rubber. For stretch ratio below about 1.25, a good agreement is observed between theory and experiments. Above this threshold, some deviations from the theoretical predictions are induced as a result of the departure of the mechanical response of the silicone rubber from the neo-Hokeean description embedded in the model.

  1. Effect of Mechanical Stretching of the Skin on Collagen Fibril ...

    African Journals Online (AJOL)

    Dell

    It was recently established that, deformation of connective tissue cells under the influence of mechanical stretching intensifies the synthesis of structural biopolymers, particularly those of the collagen molecules, which are capable of associating into fibrils by self assembly (Buschmann et al., 1995,. Garbuzenko et al., 1997; ...

  2. Bruxism: Is There an Indication for Muscle-Stretching Exercises?

    NARCIS (Netherlands)

    Gouw, S.; Wijer, A. de; Creugers, N.H.J.; Kalaykova, S.I.

    2017-01-01

    Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism.

  3. Sport stretching : Effect on passive muscle stiffness of short hamstrings

    NARCIS (Netherlands)

    Halbertsma, JPK; vanBolhuis, AI; Goeken, LNH

    Objective: To evaluate the effects of one 10-minute stretch on muscle stiffness in subjects with short hamstrings. Design: Randomized control trial. Setting: Laboratory for human movement sciences in the department of rehabilitation of a university hospital. Subjects: Sixteen students from the

  4. The health of benthic diatom assemblages in lower stretch

    Indian Academy of Sciences (India)

    This study examines the ecological state of epilithic diatom assemblages along the lower stretch of Mandakini, a glacier-fed Himalayan river. The diatoms were sampled at four stations during winter and summer, only once in each season. Valve counts were obtained from Naphrax mounts prepared from each sample.

  5. A single molecule DNA flow stretching microscope for undergraduates

    NARCIS (Netherlands)

    Williams, Kelly; Grafe, Brendan; Burke, Kathryn M.; Tanner, Nathan; van Oijen, Antoine M.; Loparo, Joseph; Price, Allen C.

    2011-01-01

    The design of a simple, safe, and inexpensive single molecule flow stretching instrument is presented. The instrument uses a low cost upright microscope coupled to a webcam for imaging single DNA molecules that are tethered in an easy to construct microfluidic flow cell. The system requires no

  6. Acute effects of active isolated stretching on vertical jump ...

    African Journals Online (AJOL)

    The purpose of the study was to determine the acute effects of active isolated stretching on muscular peak power production. Sixty healthy, physically active volunteers (aged 18-28) participated as subjects in this study. Subjects were randomly assigned to two groups; the control group and the experimental group. Subjects ...

  7. Cooperativity among short amyloid stretches in long amyloidogenic sequences.

    Directory of Open Access Journals (Sweden)

    Lele Hu

    Full Text Available Amyloid fibrillar aggregates of polypeptides are associated with many neurodegenerative diseases. Short peptide segments in protein sequences may trigger aggregation. Identifying these stretches and examining their behavior in longer protein segments is critical for understanding these diseases and obtaining potential therapies. In this study, we combined machine learning and structure-based energy evaluation to examine and predict amyloidogenic segments. Our feature selection method discovered that windows consisting of long amino acid segments of ~30 residues, instead of the commonly used short hexapeptides, provided the highest accuracy. Weighted contributions of an amino acid at each position in a 27 residue window revealed three cooperative regions of short stretch, resemble the β-strand-turn-β-strand motif in A-βpeptide amyloid and β-solenoid structure of HET-s(218-289 prion (C. Using an in-house energy evaluation algorithm, the interaction energy between two short stretches in long segment is computed and incorporated as an additional feature. The algorithm successfully predicted and classified amyloid segments with an overall accuracy of 75%. Our study revealed that genome-wide amyloid segments are not only dependent on short high propensity stretches, but also on nearby residues.

  8. Force encoding in muscle spindles during stretch of passive muscle.

    Science.gov (United States)

    Blum, Kyle P; Lamotte D'Incamps, Boris; Zytnicki, Daniel; Ting, Lena H

    2017-09-01

    Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs) of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt) predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening) of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle lengthening conditions

  9. Force encoding in muscle spindles during stretch of passive muscle.

    Directory of Open Access Journals (Sweden)

    Kyle P Blum

    2017-09-01

    Full Text Available Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle

  10. Stretching skeletal muscle: chronic muscle lengthening through sarcomerogenesis.

    Directory of Open Access Journals (Sweden)

    Alexander M Zöllner

    Full Text Available Skeletal muscle responds to passive overstretch through sarcomerogenesis, the creation and serial deposition of new sarcomere units. Sarcomerogenesis is critical to muscle function: It gradually re-positions the muscle back into its optimal operating regime. Animal models of immobilization, limb lengthening, and tendon transfer have provided significant insight into muscle adaptation in vivo. Yet, to date, there is no mathematical model that allows us to predict how skeletal muscle adapts to mechanical stretch in silico. Here we propose a novel mechanistic model for chronic longitudinal muscle growth in response to passive mechanical stretch. We characterize growth through a single scalar-valued internal variable, the serial sarcomere number. Sarcomerogenesis, the evolution of this variable, is driven by the elastic mechanical stretch. To analyze realistic three-dimensional muscle geometries, we embed our model into a nonlinear finite element framework. In a chronic limb lengthening study with a muscle stretch of 1.14, the model predicts an acute sarcomere lengthening from 3.09[Formula: see text]m to 3.51[Formula: see text]m, and a chronic gradual return to the initial sarcomere length within two weeks. Compared to the experiment, the acute model error was 0.00% by design of the model; the chronic model error was 2.13%, which lies within the rage of the experimental standard deviation. Our model explains, from a mechanistic point of view, why gradual multi-step muscle lengthening is less invasive than single-step lengthening. It also explains regional variations in sarcomere length, shorter close to and longer away from the muscle-tendon interface. Once calibrated with a richer data set, our model may help surgeons to prevent muscle overstretch and make informed decisions about optimal stretch increments, stretch timing, and stretch amplitudes. We anticipate our study to open new avenues in orthopedic and reconstructive surgery and enhance

  11. Raman spectra of lithium compounds

    Science.gov (United States)

    Gorelik, V. S.; Bi, Dongxue; Voinov, Y. P.; Vodchits, A. I.; Gorshunov, B. P.; Yurasov, N. I.; Yurasova, I. I.

    2017-11-01

    The paper is devoted to the results of investigating the spontaneous Raman scattering spectra in the lithium compounds crystals in a wide spectral range by the fibre-optic spectroscopy method. We also present the stimulated Raman scattering spectra in the lithium hydroxide and lithium deuteride crystals obtained with the use of powerful laser source. The symmetry properties of the lithium hydroxide, lithium hydroxide monohydrate and lithium deuteride crystals optical modes were analyzed by means of the irreducible representations of the point symmetry groups. We have established the selection rules in the Raman and infrared absorption spectra of LiOH, LiOH·H2O and LiD crystals.

  12. Stretched versus compressed exponential kinetics in α-helix folding

    International Nuclear Information System (INIS)

    Hamm, Peter; Helbing, Jan; Bredenbeck, Jens

    2006-01-01

    In a recent paper (J. Bredenbeck, J. Helbing, J.R. Kumita, G.A. Woolley, P. Hamm, α-helix formation in a photoswitchable peptide tracked from picoseconds to microseconds by time resolved IR spectroscopy, Proc. Natl. Acad. Sci USA 102 (2005) 2379), we have investigated the folding of a photo-switchable α-helix with a kinetics that could be fit by a stretched exponential function exp(-(t/τ) β ). The stretching factor β became smaller as the temperature was lowered, a result which has been interpreted in terms of activated diffusion on a rugged energy surface. In the present paper, we discuss under which conditions diffusion problems occur with stretched exponential kinetics (β 1). We show that diffusion problems do have a strong tendency to yield stretched exponential kinetics, yet, that there are conditions (strong perturbation from equilibrium, performing the experiment in the folding direction) under which compressed exponential kinetics would be expected instead. We discuss the kinetics on free energy surfaces predicted by simple initiation-propagation models (zipper models) of α-helix folding, as well as by folding funnel models. We show that our recent experiment has been performed under condition for which models with strong downhill driving force, such as the zipper model, would predict compressed, rather than stretched exponential kinetics, in disagreement with the experimental observation. We therefore propose that the free energy surface along a reaction coordinate that governs the folding kinetics must be relatively flat and has a shape similar to a 1D golf course. We discuss how this conclusion can be unified with the thermodynamically well established zipper model by introducing an additional kinetic reaction coordinate

  13. Wrinkling instability of an inhomogeneously stretched viscous sheet

    Science.gov (United States)

    Srinivasan, Siddarth; Wei, Zhiyan; Mahadevan, L.

    2017-07-01

    Motivated by the redrawing of hot glass into thin sheets, we investigate the shape and stability of a thin viscous sheet that is inhomogeneously stretched in an imposed nonuniform temperature field. We first determine the associated base flow by solving the long-time-scale stretching flow of a flat sheet as a function of two dimensionless parameters: the normalized stretching velocity α and a dimensionless width of the heating zone β . This allows us to determine the conditions for the onset of an out-of-plane wrinkling instability stated in terms of an eigenvalue problem for a linear partial differential equation governing the displacement of the midsurface of the sheet. We show that the sheet can become unstable in two regions that are upstream and downstream of the heating zone where the minimum in-plane stress is negative. This yields the shape and growth rates of the most unstable buckling mode in both regions for various values of the stretching velocity and heating zone width. A transition from stationary to oscillatory unstable modes is found in the upstream region with increasing β , while the downstream region is always stationary. We show that the wrinkling instability can be entirely suppressed when the surface tension is large enough relative to the magnitude of the in-plane stress. Finally, we present an operating diagram that indicates regions of the parameter space that result in a required outlet sheet thickness upon stretching while simultaneously minimizing or suppressing the out-of-plane buckling, a result that is relevant for the glass redraw method used to create ultrathin glass sheets.

  14. Acute effect of different stretching methods on Illinois agility test in soccer players.

    Science.gov (United States)

    Amiri-Khorasani, Mohammadtaghi; Sahebozamani, Mansour; Tabrizi, Kourosh G; Yusof, Ashril B

    2010-10-01

    The purpose of this study was to examine the effects of static, dynamic, and the combination of static and dynamic stretching within a pre-exercise warm-up on the Illinois agility test (IAT) in soccer players. Nineteen professional soccer players (age = 22.5 ± 2.5 years, height = 1.79 ± 0.003 m, body mass = 74.8 ± 10.9 kg) were tested for agility performance using the IAT after different warm-up protocols consisting of static, dynamic, combined stretching, and no stretching. The players were subgrouped into less and more experienced players (5.12 ± 0.83 and 8.18 ± 1.16 years, respectively). There were significant decreases in agility time after no stretching, among no stretching vs. static stretching; after dynamic stretching, among static vs. dynamic stretching; and after dynamic stretching, among dynamic vs. combined stretching during warm-ups for the agility: mean ± SD data were 14.18 ± 0.66 seconds (no stretch), 14.90 ± 0.38 seconds (static), 13.95 ± 0.32 seconds (dynamic), and 14.50 ± 0.35 seconds (combined). There was significant difference between less and more experienced players after no stretching and dynamic stretching. There was significant decrease in agility time following dynamic stretching vs. static stretching in both less and more experienced players. Static stretching does not appear to be detrimental to agility performance when combined with dynamic warm-up for professional soccer players. However, dynamic stretching during the warm-up was most effective as preparation for agility performance. The data from this study suggest that more experienced players demonstrate better agility skills due to years of training and playing soccer.

  15. The effectiveness of manual stretching in the treatment of plantar heel pain: a systematic review

    Directory of Open Access Journals (Sweden)

    Parish Ben

    2011-06-01

    Full Text Available Abstract Background Plantar heel pain is a commonly occurring foot complaint. Stretching is frequently utilised as a treatment, yet a systematic review focusing only on its effectiveness has not been published. This review aimed to assess the effectiveness of stretching on pain and function in people with plantar heel pain. Methods Medline, EMBASE, CINAHL, AMED, and The Cochrane Library were searched from inception to July 2010. Studies fulfilling the inclusion criteria were independently assessed, and their quality evaluated using the modified PEDro scale. Results Six studies including 365 symptomatic participants were included. Two compared stretching with a control, one study compared stretching to an alternative intervention, one study compared stretching to both alternative and control interventions, and two compared different stretching techniques and durations. Quality rating on the modified Pedro scale varied from two to eight out of a maximum of ten points. The methodologies and interventions varied significantly between studies, making meta-analysis inappropriate. Most participants improved over the course of the studies, but when stretching was compared to alternative or control interventions, the changes only reached statistical significance in one study that used a combination of calf muscle stretches and plantar fascia stretches in their stretching programme. Another study comparing different stretching techniques, showed a statistically significant reduction in some aspects of pain in favour of plantar fascia stretching over calf stretches in the short term. Conclusions There were too few studies to assess whether stretching is effective compared to control or other interventions, for either pain or function. However, there is some evidence that plantar fascia stretching may be more effective than Achilles tendon stretching alone in the short-term. Appropriately powered randomised controlled trials, utilizing validated outcome

  16. Acute effects of constant torque and constant angle stretching on the muscle and tendon tissue properties.

    Science.gov (United States)

    Konrad, Andreas; Budini, Francesco; Tilp, Markus

    2017-08-01

    Static stretching induces acute structural changes of the muscle-tendon unit (MTU) that are related to the intensity or duration of stretching. It has been reported that stretching with a constant torque (CT) leads to greater joint range of motion changes than stretching with a constant angle (CA). Whether or not this difference is due to different structural changes of the MTUs of the lower leg and ankle plantar flexors is not known. Therefore, the purpose of this study was to compare the acute effects of single CA and CT stretching on various muscle and tendon mechanical properties. Seventeen young, healthy volunteers were tested on two separate days using either CT or CA stretching (4 × 30 s each). Before and after stretching, dorsiflexion range of motion (RoM), passive resistive torque (PRT), and maximum voluntary contraction (MVC) were measured with a dynamometer. Ultrasonography of the medial gastrocnemius (GM) muscle-tendon junction (MTJ) displacement allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate their stiffness. Maximum dorsiflexion increased while PRT, muscle-tendon stiffness, and muscle stiffness decreased following both CA and CT stretching. There was a greater increase in RoM following CT stretching compared to CA stretching. Moreover, the decline in PRT was greater during CT stretching compared to CA stretching. As expected, several functional adaptations (RoM, PRT) were different between CT and CA stretching due to the higher intensity of CT stretching. However, no structural differences in the adaptations to the stretching modalities could be detected. We suggest that the different functional adaptations between CA and CT stretching are the consequence of different adaptations in the perception of stretch and pain.

  17. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

    International Nuclear Information System (INIS)

    Ostrow, Lyle W.; Suchyna, Thomas M.; Sachs, Frederick

    2011-01-01

    Highlights: → Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. → Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca 2+ permeant SACs. → The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. → Stretch-induced ET-1 production depends on a calcium influx. → SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch ( 2+ threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

  18. Raman spectra of iodine-derivatives of tyrosine and thyronine

    International Nuclear Information System (INIS)

    Loh, E.

    1974-01-01

    The Raman spectra of the iodine derivatives of tyrosine and thyronine in the form of compressed crystalline powders have been excited by 4880 A Argon laser on rotating samples at room temperature. The strong peaks in the low-frequency, -1 , region may be described by analogous vibrations of benzene as: I. the C-I out-of-plane bendings of E 1 sub(g) mode from 100 cm -1 to 180 cm -1 ; II. the C-I in-plane bendings of E 2 sub(g) and A 2 sub(g) mode from 190 cm -1 to 330 cm -1 and III. the C-I stretchings of E 2 sub(g) mode from 330 cm -1 to 400 cm -1 . In 3,3',5-triiodo-derivatives, the number of both the C-I in-plane bendings and C-I stretchings on the inner phenyl ring approximately doubles from thet of diiodo-derivatives. This doubling in number of peaks is presumably due to the modulation caused by the libration, which is associated with the C-I out-of-plane bending at position 3', of the outer phenyl ring

  19. Infrared spectra of mineral species

    CERN Document Server

    Chukanov, Nikita V

    2014-01-01

    This book details more than 3,000 IR spectra of more than 2,000 mineral species collected during last 30 years. It features full descriptions and analytical data of each sample for which IR spectrum was obtained.

  20. Infrared spectra of BeSo4.4H2O and its deuterated analogue in 4000-1200 cm-1 region

    International Nuclear Information System (INIS)

    Srivastava, B.K.; Khandelwal, D.P.; Bist, H.D.

    1976-01-01

    IR spectra of BeSO 4 .4H 2 O and its deuterated analogue at approximately 300 K and approximately 110 K are reported in the region 4000-1200 cm -1 using thin film and nujol mull techniques. The observed bands have been assigned as the internal modes of the water and the oVertones and combinations of various modes using the recently revised assignments of SO 4 2- and Be(aq) 4 fundamentals in the region 120g-250 cmsub(-) 1 . The splitting of the internal modes of water has been discussed in the light of the effects of deuteration and cooling and it is shown that all the water molecules in a unit cell are asymmetric but crystallographically equivalent. (author)

  1. Sequential Analysis of Gamma Spectra

    International Nuclear Information System (INIS)

    Fayez-Hassan, M.; Hella, Kh.M.

    2009-01-01

    This work shows how easy one can deal with a huge number of gamma spectra. The method can be used for radiation monitoring. It is based on the macro feature of the windows XP connected to QBASIC software. The routine was used usefully in generating accurate results free from human errors. One hundred measured gamma spectra were fully analyzed in 10 minutes using our fast and automated method controlling the Genie 2000 gamma acquisition analysis software.

  2. Spectra and structure of gallium compounds. Part X. Infrared and Raman spectra, vibrational assignment, and normal coordinate calculations for trimethylaminegallium trichloride

    Science.gov (United States)

    Durig, J. R.; Chatterjee, K. K.

    The far IR (450-480 cm-1) and Raman (3200-3230 cm-1) spectra of (CH3)3 NGaCl3 have been recorded in the solid state and interpreted in detail on the basis of C3 molecular symmetry. A modified valence force field model is used to calculate the frequencies and potential energy distribution of the adduct. The calculated force constants of the adduct are compared with those previously reported for the free Lewis acid and the free Lewis base moieties, and the observed differences ascribed to geometrical changes of the uncomplexed species on adduct formation and explained on the basis of the VSEPR model and non-bond interactions. Extensive coupling is observed between the GaN stretching mode and the NC3 symmetric stretching and the NC3 symmetric deformational modes. Strong coupling interaction is also found between the GaCl3 antisymmetric stretch and the NC3 antisymmetric deformation. The calculated value of 2.50 mdyn Å-1 for the GaN stretching force constant in (CH3)3NGaCl3 is larger than any of those previously determined in complexes such as (CH3)3NGaH3 (2.43 mdyn Å-1), (CH3)3NGa(CH3)3 (1.61 mdyn Å-1), and H3NGa(CH3)3 (1.08 mdyn Å-1). The observed variations in the magnitudes of the stretching force constants of the donor-acceptor dative bond is found to be consistent with the estimated relative stabilities of this series of adducts.

  3. Response spectra in alluvial soils

    International Nuclear Information System (INIS)

    Chandrasekharan, A.R.; Paul, D.K.

    1975-01-01

    For aseismic design of structures, the ground motion data is assumed either in the form of ground acceleration as a function of time or indirectly in the form of response spectra. Though the response spectra approach has limitations like not being applicable for nonlinear problems, it is usually used for structures like nuclear power plants. Fifty accelerograms recorded at alluvial sites have been processed. Since different empirical formulas relating acceleration with magnitude and distance give a wide scatter of values, peak ground acceleration alone cannot be the parameter as is assumed by a number of authors. The spectra corresponding to 5% damping have been normalised with respect to three parameters, namely, peak ground acceleration, peak ground velocity and a nondimensional quantity ad/v 2 . Envelopee of maxima and minima as well as average response spectra has been obtained. A comparison with the USAEC spectra has been made. A relation between ground acceleration, ground velocity and ad/v 2 has been obtained which would nearly give the same magnification of the response. A design response spectra for alluvial soils has been recommended. (author)

  4. Coherent infrared multidimensional spectra of the OH stretching band in liquid water simulated by direct nonlinear exciton propagation

    Science.gov (United States)

    Falvo, Cyril; Palmieri, Benoit; Mukamel, Shaul

    2009-05-01

    The two-dimensional vibrational response of the disordered strongly fluctuating OH exciton band in liquid water is investigated using a new simulation protocol. The direct nonlinear exciton propagation generalizes the nonlinear exciton equations to include nonadiabatic time dependent Hamiltonian and transition dipole fluctuations. The excitonic picture is retained and the large cancellation between Liouville pathways is built-in from the outset. The sensitivity of the photon echo and double-quantum-coherence techniques to frequency fluctuations, molecular reorientation, intermolecular coupling, and the two-exciton coherence is investigated. The photon echo is particularly sensitive to the frequency fluctuations and molecular reorientation, whereas the double-quantum coherence provides a unique probe for intermolecular couplings and two-exciton coherence.

  5. Acute Effect of Static Stretching Exercise on Arterial Stiffness in Healthy Young Adults.

    Science.gov (United States)

    Yamato, Yosuke; Hasegawa, Natsuki; Sato, Koji; Hamaoka, Takafumi; Ogoh, Shigehiko; Iemitsu, Motoyuki

    2016-10-01

    Habitual stretching exercise increases carotid arterial compliance, and acute stretching exercise increases arterial compliance in patients with myocardial infarction. However, it is not known whether this arterial adaptation is sustained after exercise. The aim of this study was to examine the effect of a single bout of stretching exercise on the time course of systemic, central, and peripheral arterial stiffness in healthy young subjects. Twenty-six healthy young men performed static stretching exercise involving the entire body (trunk, upper limb, and lower limb) for 40 mins. Pulse-wave velocity (PWV; an index of arterial stiffness), blood pressure, and heart rate were measured before and 0, 15, 30, and 60 mins after stretching exercise. Femoral-ankle PWV and brachial-ankle PWV were reduced relative to baseline 15 and 30 mins after acute stretching (P stretch stimulation may result in chronic high arterial compliance, although a single bout of stretch exercise acutely affects arterial compliance.

  6. Number of repetition after different rest intervals between static stretching and resistance training

    Directory of Open Access Journals (Sweden)

    H. Dias

    2017-09-01

    Conclusions: Therefore, 30-minute interval between static stretching and resistance exercises was needed to achieve greater repetition performance. Thus, static stretching for lower limbs may be avoided before a resistance training session.

  7. Direct simulations of anharmonic infrared spectra using quantum mechanical/effective fragment potential molecular dynamics (QM/EFP-MD): methanol in water.

    Science.gov (United States)

    Ghosh, Manik Kumer; Lee, Jooyong; Choi, Cheol Ho; Cho, Minhaeng

    2012-09-13

    One of the most stringent tests for chemical accuracy of a hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics simulation method would be to directly compare the calculated vibrational spectra with the corresponding experimental results. Here, the applicability of hybrid QM/effective fragment potential (EFP) to the simulations of methanol infrared spectra is investigated in detail. It is demonstrated that the QM/EFP simulations in combination with time correlation function theory yield not only the fundamental transition bands but also the major overtone and combination bands of methanol dissolved in water in both mid- and near-IR regions. This clearly indicates that the QM/EFP-molecular dynamics can be a viable way of obtaining an anharmonic infrared spectrum that provides information on solvatochromic frequency shifts and fluctuations, solute-solvent interaction-induced dephasing, and anharmonic coupling effects on vibrational spectra of aqueous solutions. We anticipate that the computational protocol developed here can be effectively used to simulate both one- and two-dimensional vibrational spectra of biomolecules and chemically reactive systems in condensed phases.

  8. Acute Effects of Dynamic Stretching on Muscle Flexibility and Performance: An Analysis of the Current Literature.

    Science.gov (United States)

    Opplert, Jules; Babault, Nicolas

    2018-02-01

    Stretching has long been used in many physical activities to increase range of motion (ROM) around a joint. Stretching also has other acute effects on the neuromuscular system. For instance, significant reductions in maximal voluntary strength, muscle power or evoked contractile properties have been recorded immediately after a single bout of static stretching, raising interest in other stretching modalities. Thus, the effects of dynamic stretching on subsequent muscular performance have been questioned. This review aimed to investigate performance and physiological alterations following dynamic stretching. There is a substantial amount of evidence pointing out the positive effects on ROM and subsequent performance (force, power, sprint and jump). The larger ROM would be mainly attributable to reduced stiffness of the muscle-tendon unit, while the improved muscular performance to temperature and potentiation-related mechanisms caused by the voluntary contraction associated with dynamic stretching. Therefore, if the goal of a warm-up is to increase joint ROM and to enhance muscle force and/or power, dynamic stretching seems to be a suitable alternative to static stretching. Nevertheless, numerous studies reporting no alteration or even performance impairment have highlighted possible mitigating factors (such as stretch duration, amplitude or velocity). Accordingly, ballistic stretching, a form of dynamic stretching with greater velocities, would be less beneficial than controlled dynamic stretching. Notwithstanding, the literature shows that inconsistent description of stretch procedures has been an important deterrent to reaching a clear consensus. In this review, we highlight the need for future studies reporting homogeneous, clearly described stretching protocols, and propose a clarified stretching terminology and methodology.

  9. Oxygen infrared spectra of oxyhemoglobins and oxymyoglobins. Evidence of two major liganded O2 structures

    International Nuclear Information System (INIS)

    Potter, W.T.; Tucker, M.P.; Houtchens, R.A.; Caughey, W.S.

    1987-01-01

    The dioxygen stretch bands in infrared spectra for solutions of oxy species of human hemoglobin A and its separated subunits, human mutant hemoglobin Zurich (β63His to Arg), rabbit hemoglobin, lamprey, hemoglobin, sperm whale myoglobin, bovine myoglobin, and a sea worm chlorocruorin are examined. Each protein exhibits multiple isotope-sensitive bands between 1160 and 1060 cm -1 for the liganded 16 O 2 , 17 O 2 , and 18 O 2 . The O-O stretch bands for each of the mammalian myoglobins and hemoglobins are similar, with frequencies that differ between proteins by only 3-5 cm -1 . The spectra for the lamprey and sea worm hemoglobins exhibit greater diversity. For all proteins an O-O stretch band expected to occur near 1125 cm -1 for 16 O 2 and 17 O 2 , but not 18 O 2 , appears split by ∼25 cm -1 due to an unidentified perturbation. The spectrum for each dioxygen isotope, if unperturbed, would contain two strong bands for the mammalian myoglobins (1150 and 1120 cm -1 ) and hemoglobins (1155 and 1125 cm -1 ). Two strong bands separated by ∼30 cm -1 for each oxy heme protein subunit indicate that two major protein conformations (structure) that differ substantially in O 2 bonding are present. The two dioxygen structures can result from a combination of dynamic distal and proximal effects upon the O 2 ligand bound in a bent-end-on stereochemistry

  10. Spectra and structure of gallium compounds. Part IX . Infrared and Raman spectra of trimethylphosphinegallium trichloride and normal coordinate calculations of gallium trichloride and the adduct

    Science.gov (United States)

    Durig, J. R.; Chatterjee, K. K.

    1982-05-01

    The infrared (3200-50 cm -1)and the Raman (3200-30 cm -1) spectra of (CH 3) 3PGaCI 3 have been recorded for the solid state. The spectra are interpreted on the basis of an effective C3v molecular symmetry for the crystalline state and a complete vibrational assignment except for the torsional modes is presented. The frequencies and potential energy distribution for GaCl 3 and those of the adduct have been calculated utilizing a modified valence force field model. A comparison of the calculated potential constants for the adduct with those of the free Lewis acid and base is made and the differences are shown to be consistent with structural changes upon adduct formation and explained in terms of the VSEPR model. Extensive coupling is observed between the GaP stretching mode and the GaCI 3 and the PC 3 stretching and symmetric deformational modes. Various degrees of coupling are also observed between other skeletal modes of vibration, including coupling between the PC 3 and GaCI 3 rocking motions. The value of 2.01 mdyn Å -1 for the GaP stretching force constant is the same as that previously determined for the same constant for (CH 3) 3PGaH 3. Several weak bands, observed in the low frequency region of the infrared and Raman spectra of crystalline (CH 3) 3PGaCl 3, are characterized as lattice modes arising from intermolecular librations. These results are compared to the similar quantities in some corresponding molecules.

  11. Vibrational spectra and molecular conformation of taurine and its related compounds

    Science.gov (United States)

    Ohno, Keiichi; Mandai, Yoshitaka; Matsuura, Hiroatsu

    1992-04-01

    IR and Raman spectra have been measured for taurine (2-aminoethanesulfonic acid) and its sodium salt in the solid state and Raman spectra for aqueous solutions of taurine with different pH values. Normal coordinate treatment has been carried out. The analysis of the spectra has indicated that, in the solid state, the molecule of taurine takes the gauche form while that of the sodium salt takes the trans form, and that the trans and gauche forms coexist in both acidic and basic aqueous solutions. The CS stretching bands for the gauche and trans forms were observed at 742 cm -1 and 803 cm -1 respectively. These bands were applied to a conformational analysis of other compounds containing a taurine skeleton; sodium taurocholate takes the gauche conformation about the bond axis NCCS.

  12. Correlations between physical properties, formulations, and ATR FTIR spectra of polyurethane foams

    Science.gov (United States)

    Caughran, Joel A.; Bhat, Sanmitra A.; de Haseth, James A.

    1994-01-01

    Polyurethane foams of varying surfactant, tin catalyst, and amine catalyst levels were prepared to find formulations that made `good' foams. A good foam is characterized by rise and density. Attenuated Total Reflectance spectra of the foams were collected after the foams were allowed to cure for 24 hours. Because the infrared spectrum shows morphology as well as structure, the ATR spectrum can be used to measure physical properties that are dependent on structure and morphology. The ATR FT-IR spectra were baseline corrected and then normalized by the area in the C-H stretch region to correct for differences in contact area with the ATR crystal. Samples were then taken from the cured foam parallel to the direction of rise to measure tensile strength and air permeability. Correlations were then made between the ATR spectra and the physical properties. Partial least squares (PLS) and principle component regression (PCR) were used to do the correlations.

  13. High spectral resolution imaging of the dynamical atmosphere of the red supergiant Antares in the CO first overtone lines with VLTI/AMBER

    Science.gov (United States)

    Ohnaka, K.; Hofmann, K.-H.; Schertl, D.; Weigelt, G.; Baffa, C.; Chelli, A.; Petrov, R.; Robbe-Dubois, S.

    2013-07-01

    Aims: We present aperture-synthesis imaging of the red supergiant Antares (α Sco) in the CO first overtone lines. Our goal is to probe the structure and dynamics of the outer atmosphere. Methods: Antares was observed between 2.28 μm and 2.31 μm with VLTI/AMBER with spectral resolutions of up to 12 000 and angular resolutions as high as 7.2 mas at two epochs with a time interval of one year. Results: The reconstructed images in individual CO lines reveal that the star appears differently in the blue wing, line center, and red wing. In 2009, the images in the line center and red wing show an asymmetrically extended component, while the image in the blue wing shows little trace of it. In 2010, however, the extended component appears in the line center and blue wing, and the image in the red wing shows only a weak signature of the extended component. Our modeling of these AMBER data suggests that there is an outer atmosphere (MOLsphere) extending to 1.2-1.4 R⋆ with CO column densities of (0.5-1) × 1020 cm-2 and a temperature of ~2000 K. The CO line images observed in 2009 can be explained by a model in which a large patch or clump of CO gas is infalling at only 0-5 km s-1, while the CO gas in the remaining region is moving outward much faster at 20-30 km s-1. The images observed in 2010 suggest that a large clump of CO gas is moving outward at 0-5 km s-1, while the CO gas in the remaining region is infalling much faster at 20-30 km s-1. In contrast to the images in the CO lines, the AMBER data in the continuum show only a slight deviation from limb-darkened disks and only marginal time variations. We derive a limb-darkened disk diameter of 37.38 ± 0.06 mas and a power-law-type limb-darkening parameter of (8.7 ± 1.6) × 10-2 (2009) and 37.31 ± 0.09 mas and (1.5 ± 0.2) × 10-1 (2010). We also obtain an effective temperature of 3660 ± 120 K (the error includes the effects of the temporal flux variation that is assumed to be the same as Betelgeuse) and a

  14. Directing Spinal Cord Plasticity: The Impact of Stretch Therapy on Functional Recovery after Spinal Cord Injury

    Science.gov (United States)

    2013-10-01

    weight. 15. SUBJECT TERMS Spinal cord injury, stretching, physical therapy , rehabilitation, locomotor recovery 16. SECURITY CLASSIFICATION OF...David S. K. Magnuson, PhD. University of Louisville. Introduction: This research focuses on the impact of stretching ( physical therapy maneuvers...lesions. Physical therapists use stretching maneuvers to maintain extensibility of soft tissues and to manage spasticity . Previous studies in our lab

  15. Can Stretching Prior to Exercise and Sports Improve Performance and Prevent Injury?

    Science.gov (United States)

    Bracko, Michael R.

    2002-01-01

    Examines data from research on stretching as it relates to enhanced performance and injury prevention so that fitness, exercise, and sports performance professionals can make informed decisions about stretching programs for clients. The paper notes that stretching is a misunderstood component of fitness and sports training. Few studies show…

  16. The effects of different volumes of dynamic stretching on 20-M ...

    African Journals Online (AJOL)

    ... each sprint) following different volumes of dynamic stretching (DSS1, DSS2 and DSS3). The results showed no significant difference for all parameters between all the all dynamic stretching volumes. Results show that any of the dynamic stretching volumes may be used as a warm up prior to the repeated sprints session.

  17. DNA analysis by single molecule stretching in nanofluidic biochips

    DEFF Research Database (Denmark)

    Abad, E.; Juarros, A.; Retolaza, A.

    2011-01-01

    Stretching single DNA molecules by confinement in nanofluidic channels has attracted a great interest during the last few years as a DNA analysis tool. We have designed and fabricated a sealed micro/nanofluidic device for DNA stretching applications, based on the use of the high throughput Nano......Imprint Lithography (NIL) technology combined with a conventional anodic bonding of the silicon base and Pyrex cover. Using this chip, we have performed single molecule imaging on a bench-top fluorescent microscope system. Lambda phage DNA was used as a model sample to characterize the chip. Single molecules of λ...... a method to determining DNA size. The results of this work prove that the developed fabrication process is a good alternative for the fabrication of single molecule DNA biochips and it allows developing a variety of innovative bio/chemical sensors based on single-molecule DNA sequencing devices....

  18. Unexpected decoupling of stretching and bending modes in protein gels.

    Science.gov (United States)

    Gibaud, Thomas; Zaccone, Alessio; Del Gado, Emanuela; Trappe, Véronique; Schurtenberger, Peter

    2013-02-01

    We show that gels formed by arrested spinodal decomposition of protein solutions exhibit elastic properties in two distinct frequency domains, both elastic moduli exhibiting a remarkably strong dependence on volume fraction. Considering the large difference between the protein size and the characteristic length of the network we model the gels as porous media and show that the high and low frequency elastic moduli can be respectively attributed to stretching and bending modes. The unexpected decoupling of the two modes in the frequency domain is attributed to the length scale involved: while stretching mainly relates to the relative displacement of two particles, bending involves the deformation of a strand with a thickness of the order of a thousand particle diameters.

  19. Progressive muscle relaxation, yoga stretching, and ABC relaxation theory.

    Science.gov (United States)

    Ghoncheh, Shahyad; Smith, Jonathan C

    2004-01-01

    This study compared the psychological effects of progressive muscle relaxation (PMR) and yoga stretching (hatha) exercises. Forty participants were randomly divided into two groups and taught PMR or yoga stretching exercises. Both groups practiced once a week for five weeks and were given the Smith Relaxation States Inventory before and after each session. As hypothesized, practitioners of PMR displayed higher levels of relaxation states (R-States) Physical Relaxation and Disengagement at Week 4 and higher levels of Mental Quiet and Joy as a posttraining aftereffect at Week 5. Contrary to what was hypothesized, groups did not display different levels of R-States Energized or Aware. Results suggest the value of supplementing traditional somatic conceptualizations of relaxation with the psychological approach embodied in ABC relaxation theory. Clinical and research implications are discussed. Copyright 2003 Wiley Periodicals, Inc. J Clin Psychol.

  20. FUZZY BASED CONTRAST STRETCHING FOR MEDICAL IMAGE ENHANCEMENT

    Directory of Open Access Journals (Sweden)

    T.C. Raja Kumar

    2011-07-01

    Full Text Available Contrast Stretching is an important part in medical image processing applications. Contrast is the difference between two adjacent pixels. Fuzzy statistical values are analyzed and better results are produced in the spatial domain of the input image. The histogram mapping produces the resultant image with less impulsive noise and smooth nature. The probabilities of gray values are generated and the fuzzy set is determined from the position of the input image pixel. The result indicates the good performance of the proposed fuzzy based stretching. The inverse transform of the real values are mapped with the input image to generate the fuzzy statistics. This approach gives a flexible image enhancement for medical images in the presence of noises.

  1. Convective Flow of Sisko Fluid over a Bidirectional Stretching Surface.

    Science.gov (United States)

    Munir, Asif; Shahzad, Azeem; Khan, Masood

    2015-01-01

    The present investigation focuses the flow and heat transfer characteristics of the steady three-dimensional Sisko fluid driven by a bidirectional stretching sheet. The modeled partial differential equations are reduced to coupled ordinary differential equations by a suitable transformation. The resulting equations are solved numerically by the shooting method using adaptive Runge Kutta algorithm in combination with Newton's method in the domain [0,∞). The numerical results for the velocity and temperature fields are graphically presented and effects of the relevant parameters are discussed in detail. Moreover, the skin-friction coefficient and local Nusselt number for different values of the power-law index and stretching ratio parameter are presented through tabulated data. The numerical results are also verified with the results obtained analytically by the homotopy analysis method (HAM). Additionally, the results are validated with previously published pertinent literature as a limiting case of the problem.

  2. Mechanical stretch modulates cell migration in the lungs.

    Science.gov (United States)

    López-Martínez, Cecilia; Huidobro, Covadonga; Albaiceta, Guillermo M; López-Alonso, Inés

    2018-01-01

    Cell migration is a core process to preserve homeostasis. Release of chemotactic signals induces changes in cell cytoskeleton to facilitate migration. This includes the rearrangement of cytoskeleton, genomic reprogramming and the modification of the surrounding extracellular matrix (ECM) to allow the motion of cells through. In the special case of repair after acute lung injury, cells must migrate while exposed to an increased mechanical stretch caused either by an increased work of breathing or positive-pressure ventilation. Interestingly, the cell response to this increased mechanical load can modify virtually all the mechanisms involved in cell migration. In this review we explore the interplay between stretch and the machinery responsible for cell migration. A translational approach to find new therapies in acute lung injury must take into account these interactions in order to develop effective treatments that promote lung repair.

  3. Device for stretching tapes or cables intended for manipulators

    International Nuclear Information System (INIS)

    Baudoin, J.-C.; Oger, Robert.

    1975-01-01

    The invention relates to a device for stretching tapes (or cables) intended for remote handling devices. Said equipment consists of a spring system continuously applying a constant tensile stress to said tapes (or cables) in view of taking up the slack in the latter. Said spring system is fastened to a supporting bar able to be rigidly connected to a member of the remote handling device [fr

  4. Anomalies in the coil-stretch transition of flexible polymers

    Science.gov (United States)

    Ghosal, Aishani; Cherayil, Binny J.

    2018-03-01

    The flow-induced coil-stretch transition of high molecular weight polymers has generally been held to be of first order. But evidence of significant slowing down in the rate at which the polymers relax to equilibrium in the vicinity of the transition suggests that the thermodynamic character of the transition may be less clear-cut. The above slowing down effect is actually characteristic of a second-order transition, and it points to the existence of a broad spectrum of conformational states in the transition region, analogous to the existence of fluctuations of all length scales at a critical point. In this paper, using a path integral approach based on a free-draining finitely extensible chain model, we calculate various polymer properties as a function of elongational flow as a way of exploring different statistical mechanical details of the coil-stretch transition. These properties include the molecular weight dependence of the flow-extension curve of the polymer, the distribution of its steady-state end-to-end distances, and the characteristic relaxation time τR of these distances. Among other findings, our calculations indicate that the coil-stretch transition is discontinuous in the N → ∞ limit, that the effective free energy of the chain is unimodal at all values of the flow, becoming broad and flat in the immediate vicinity of the transition, and that the ratio of τR to the Rouse relaxation time increases abruptly at the transition before eventually reaching a plateau value at large flow strengths. These aspects of the coil-stretch transition place it among a larger class of unconventional nominally first-order single chain transitions that include the adsorption transition of surface-tethered polymers and the escape transition of compressed polymers.

  5. Effect of hexane treatment and uniaxial stretching on bending ...

    African Journals Online (AJOL)

    ... β31, defined as the bending piezoelectric stress constant, was calculated. After hexane treatment and uniaxial stretching of the PVDF film, the value of β31 was 5.75 mV/m and 8.00 mV/m for draw ratio of 1.5 and 2.5 was recorded. Fourier transform Infra-red (FTIR) spectrophotometry was used for structural investigations.

  6. Growth on demand: reviewing the mechanobiology of stretched skin.

    Science.gov (United States)

    Zöllner, Alexander M; Holland, Maria A; Honda, Kord S; Gosain, Arun K; Kuhl, Ellen

    2013-12-01

    Skin is a highly dynamic, autoregulated, living system that responds to mechanical stretch through a net gain in skin surface area. Tissue expansion uses the concept of controlled overstretch to grow extra skin for defect repair in situ. While the short-term mechanics of stretched skin have been studied intensely by testing explanted tissue samples ex vivo, we know very little about the long-term biomechanics and mechanobiology of living skin in vivo. Here we explore the long-term effects of mechanical stretch on the characteristics of living skin using a mathematical model for skin growth. We review the molecular mechanisms by which skin responds to mechanical loading and model their effects collectively in a single scalar-valued internal variable, the surface area growth. This allows us to adopt a continuum model for growing skin based on the multiplicative decomposition of the deformation gradient into a reversible elastic and an irreversible growth part. To demonstrate the inherent modularity of this approach, we implement growth as a user-defined constitutive subroutine into the general purpose implicit finite element program Abaqus/Standard. To illustrate the features of the model, we simulate the controlled area growth of skin in response to tissue expansion with multiple filling points in time. Our results demonstrate that the field theories of continuum mechanics can reliably predict the manipulation of thin biological membranes through mechanical overstretch. Our model could serve as a valuable tool to rationalize clinical process parameters such as expander geometry, expander size, filling volume, filling pressure, and inflation timing to minimize tissue necrosis and maximize patient comfort in plastic and reconstructive surgery. While initially developed for growing skin, our model can easily be generalized to arbitrary biological structures to explore the physiology and pathology of stretch-induced growth of other living systems such as hearts

  7. DEVELOPMENT OF DEFORMATION STRIPS WHILE STRETCHING OF CYLINDRICAL SAMPLES

    Directory of Open Access Journals (Sweden)

    Y. V. Vasilevich

    2011-01-01

    Full Text Available Deformation strips have been experimentally revealed and described while stretching of cylindrical samples by means of computer thermography. It has been established that temperature of shift strip surface grows smoothly up to the stage of crack origin in material defect. Sharp growth of surface temperature occurs when tensile stresses reach tensile strength. Change in surface temperature occurs wavy after destruction (while cooling the sample. Processes of material destruction origin and development  characterize temperature changes in deformation strips.

  8. Genetic stretching factors in masseter muscle after orthognathic surgery.

    Science.gov (United States)

    Breuel, Wiebke; Krause, Micaela; Schneider, Matthias; Harzer, Winfried

    2013-09-01

    Up to 30% of patients relapse after orthognathic operations, and one reason might be incomplete neuromuscular adaptation of the masticatory muscles. Displacement of the mandible in sagittal or vertical directions, or both, leads to stretching or compression of these muscles. The aim of this study was to analyse stretching factors in 35 patients with retrognathism or prognathism of the mandible (Classes II and III). Tissue samples were taken from both sides of the masseter muscle (anterior and posterior) both before and 6 months after operation. Developmental myosin heavy chains MYH3 and MYH8, the fast and slow MYH 1, 2, and 7, and cyclo-oxygenase (COX) 2, forkhead transcription factor (FOX)O3a, calcineurin, and nuclear factor of activated T cells (NFAT)1c (stretching and regeneration-specific), were analysed by real time polymerase chain reaction (PCR). Correlations of Class II and III with sagittal and vertical cephalometric measurements ANB and ML-NL-angle were examined, and the results showed significant differences in amounts of MYH8 (pstretching indicators FOXO3a, calcineurin, and NFAT1c only in Class II patients. This means that stretching of the masseter muscle caused by lengthening of the mandible and raising of the bite in Class II patients was more likely to lead to relapse (similar to that in patients with open bite) than in Class III patients. In conclusion, deep bite should be reduced more by incisor intrusion than by skeletal opening. The focus in these patients should be directed towards physiotherapeutic strengthening of the muscles of mastication, and more consideration should be given to change in the vertical dimension. Copyright © 2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  9. Statistical analysis of stretch film production process capabilities

    OpenAIRE

    Kovačić, Goran; Kondić, Živko

    2012-01-01

    The basic concept of statistical process control is based on the comparison of data collected from the process with calculated control limits and conclusions about the process based on the above. This process is recognized as a modern method for the analysis of process capabilities over different capability indexes. This paper describes the application of this method in monitoring and analysis of stretch film production process capabilities.

  10. A discrete electromechanical model for human cardiac tissue: effects of stretch-activated currents and stretch conditions on restitution properties and spiral wave dynamics.

    Directory of Open Access Journals (Sweden)

    Louis D Weise

    Full Text Available We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006 and tension development (adjusted Niederer, Hunter, Smith, 2006 model with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material. Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning.

  11. Longitudinal Stretching for Maturation of Vascular Tissues Using Magnetic Forces

    Directory of Open Access Journals (Sweden)

    Timothy R. Olsen

    2016-11-01

    Full Text Available Cellular spheroids were studied to determine their use as “bioinks” in the biofabrication of tissue engineered constructs. Specifically, magnetic forces were used to mediate the cyclic longitudinal stretching of tissues composed of Janus magnetic cellular spheroids (JMCSs, as part of a post-processing method for enhancing the deposition and mechanical properties of an extracellular matrix (ECM. The purpose was to accelerate the conventional tissue maturation process via novel post-processing techniques that accelerate the functional, structural, and mechanical mimicking of native tissues. The results of a forty-day study of JMCSs indicated an expression of collagen I, collagen IV, elastin, and fibronectin, which are important vascular ECM proteins. Most notably, the subsequent exposure of fused tissue sheets composed of JMCSs to magnetic forces did not hinder the production of these key proteins. Quantitative results demonstrate that cyclic longitudinal stretching of the tissue sheets mediated by these magnetic forces increased the Young’s modulus and induced collagen fiber alignment over a seven day period, when compared to statically conditioned controls. Specifically, the elastin and collagen content of these dynamically-conditioned sheets were 35- and three-fold greater, respectively, at seven days compared to the statically-conditioned controls at three days. These findings indicate the potential of using magnetic forces in tissue maturation, specifically through the cyclic longitudinal stretching of tissues.

  12. Anomalous thermal response of silicene to uniaxial stretching

    Science.gov (United States)

    Hu, Ming; Zhang, Xiaoliang; Poulikakos, Dimos

    2013-05-01

    Silicene—the silicon counterpart of graphene—has a two-dimensional structure that leads to a host of interesting physical and chemical properties of significant utility. We report here an investigation with nonequilibrium molecular dynamics simulations of thermal transport in a single-layer silicene sheet under uniaxial stretching. We discovered that, contrary to its counterpart of graphene and despite the similarity of their honeycomb lattice structure, silicene exhibits an anomalous thermal response to tensile strain: The thermal conductivity of silicene and silicene nanoribbons first increases significantly with applied tensile strain rather than decreasing and then fluctuates at an elevated plateau. By quantifying the relative contribution from different phonon polarizations, we show first that the phonon transport in silicene is dominated by the out-of-plane flexural modes, similar to graphene. We attribute subsequently the unexpected and markedly different behavior of silicene to the interplay between two competing mechanisms governing heat conduction in a stretched silicene sheet, namely, (1) uniaxial stretching modulation in the longitudinal direction significantly depressing the phonon group velocities of longitudinal and transverse modes (phonon softening) and hindering heat conduction, and (2) phonon stiffening in the flexural modes counteracting the phonon softening effect and facilitating thermal transport. The abnormal behavior of the silicene sheet is further correlated to the unique deformation characteristics of its hexagonal lattice. Our study offers perspectives of modulating the thermal properties of low-dimensional structures for applications such as thermoelectric, photovoltaic, and optoelectronic devices.

  13. A Novel Stretch Sensor to Measure Venous Hemodynamics

    Directory of Open Access Journals (Sweden)

    Syrpailyne Wankhar

    2018-07-01

    Full Text Available Chronic venous insufficiency is a debilitating condition causing varicose veins and venous ulcers. The pathophysiology includes reflux and venous obstruction. The diagnosis is often made by clinical examination and confirmed by Venous Doppler studies. Plethysmography helps to quantitatively examine the reflux and diagnose the burden of deep venous pathology to better understand venous hemodynamics, which is not elicited by venous duplex examination alone. However, most of these tests are qualitative, expensive, and not easily available. In this paper, we demonstrate the potential use of a novel stretch sensor in the assessment of venous hemodynamics during different maneuvers by measuring the change in calf circumference. We designed the stretch sensor by using semiconductor strain gauges pasted onto a small metal bar to form a load cell. The elastic and Velcro material attached to the load cell form a belt. It converts the change in limb circumference to a proportional tension (force of distension when placed around the calf muscle. We recorded the change in limb circumference from arrays of stretch sensors by using an in-house data acquisition system. We calculated the venous volume (VV, venous filling index (VFI, ejection fraction (EF and residual venous volume (RVV on two normal subjects and on two patients to assess venous hemodynamics. The values (VV > 60 ml, VFI 60%, RVV 2ml/s, EF 35% in patients were comparable to those reported in the literature.

  14. Comparing the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men.

    Science.gov (United States)

    Ferguson, Steven L; Kim, Eonho; Seo, Dong-Il; Bemben, Michael G

    2013-12-01

    This study compared the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men. Twenty-one men were randomly assigned to vibration-stretching (VS; n = 8), vibration only (VO; n = 6), or stretching only (SO; n = 7) groups that trained 3 times per week for 3 weeks. All 3 groups performed 9 total sets of 30-second stretches. The VS group performed four 30-second upper-body vibration exercises and five 30-second upper-body stretching exercises. The VO group performed nine 30-second upper-body vibration exercises. The SO group performed nine 30-second upper-body stretching exercises. Shoulder flexion (SF), shoulder extension (SE), and shoulder transverse extension (STE) were assessed by a Leighton Flexometer and back scratch tests bilaterally (BSR, BSL) were measured via tape measure. A 1-way analysis of variance (ANOVA) evaluated groups at baseline and a 2-way repeated-measures ANOVA evaluated the interventions over time. At baseline, there were no group differences in age, height, or weight. There was a significant (p alone or combined with stretching, is a viable alternative to a standard stretching routine when attempting to increase shoulder flexibility. Adding vibration training to a flexibility regimen may improve the likelihood of regularly performing flexibility sessions because of increased variety.

  15. Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

    DEFF Research Database (Denmark)

    Caserotti, Paolo; Aagaard, Per; Simonsen, Erik Bruun

    2001-01-01

    Aging, muscle power, stretch-shortening cycle, eccentric muscle actions, concentric contractions......Aging, muscle power, stretch-shortening cycle, eccentric muscle actions, concentric contractions...

  16. Ca{sup 2+} influx and ATP release mediated by mechanical stretch in human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Naohiko [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Ito, Satoru, E-mail: itori@med.nagoya-u.ac.jp [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Furuya, Kishio [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Takahara, Norihiro [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Naruse, Keiji [Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Okayama 700-8558 (Japan); Aso, Hiromichi; Kondo, Masashi [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Sokabe, Masahiro [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Hasegawa, Yoshinori [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan)

    2014-10-10

    Highlights: • Uniaxial stretching activates Ca{sup 2+} signaling in human lung fibroblasts. • Stretch-induced intracellular Ca{sup 2+} elevation is mainly via Ca{sup 2+} influx. • Mechanical strain enhances ATP release from fibroblasts. • Stretch-induced Ca{sup 2+} influx is not mediated by released ATP or actin cytoskeleton. - Abstract: One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10–30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca{sup 2+}]{sub i} transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca{sup 2+}]{sub i}. The stretch-induced [Ca{sup 2+}]{sub i} elevation was attenuated in Ca{sup 2+}-free solution. In contrast, the increase of [Ca{sup 2+}]{sub i} by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd{sup 3+}, ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca{sup 2+}]{sub i} elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca{sup 2+} influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP.

  17. A comparison of assisted and unassisted proprioceptive neuromuscular facilitation techniques and static stretching.

    Science.gov (United States)

    Maddigan, Meaghan E; Peach, Ashley A; Behm, David G

    2012-05-01

    A comparison of assisted and unassisted proprioceptive neuromuscular facilitation techniques and static stretching. J Strength Cond Res 26(5): 1238-1244, 2012-Proprioceptive neuromuscular facilitation (PNF) stretching often requires a partner. Straps are available allowing an individual to perform PNF stretching alone. It is not known if a strap provides similar improvements in the range of motion (ROM) as partner-assisted PNF or static stretching. The purpose of this study was to compare assisted and unassisted (with a strap) PNF stretching and static stretching. Hip joint ROM, reaction time (RT), and movement time (MT) were measured prestretching and poststretching. Thirteen recreationally active adults participated in this study. The participants were subjected to 5 different stretch interventions in a random order on separate days. Stretch conditions included unassisted PNF stretching using (a) isometric, (b) concentric, and (c) eccentric contractions with a stretch strap, (d) partner-assisted isometric PNF, and (e) static stretching. The RT, MT, dynamic, active, passive hip flexion angle, and angular velocity with dynamic hip flexion were measured before and after the intervention. The ROM improved (p < 0.05) 2.6, 2.7, and 5.4%, respectively, with dynamic, active static, and passive static ROM, but there was no significant difference between the stretching protocols. There was a main effect for time (p < 0.05) with all stretching conditions negatively impacting dynamic angular velocity (9.2%). Although there was no significant effect on RT, MT showed a negative main effect for time (p < 0.05) slowing 3.4%. In conclusion, it was found that all 3 forms of active stretching provided similar improvements in the ROM and poststretching performance decrements in MT and angular velocity. Thus, individuals can implement PNF stretching techniques with a partner or alone with a strap to improve ROM, but athletes should not use these techniques before important

  18. Muscle and joint responses during and after static stretching performed at different intensities.

    Science.gov (United States)

    Freitas, Sandro R; Andrade, Ricardo J; Larcoupaille, Lilian; Mil-homens, Pedro; Nordez, Antoine

    2015-06-01

    We investigated the effects of plantarflexor static stretching of different intensities on the medial gastrocnemius (GAS) shear elastic modulus, GAS fascicle length and ankle passive torque-angle responses during and after stretching. Participants performed three stretching sessions of different intensities: 40 % (R40) of maximal dorsiflexion range of motion (ROM), 60 % (R60) of ROM, and 80 % (R80) of ROM. Each stretching lasted 10 min. The GAS architecture, GAS shear elastic modulus, ankle passive torque-angle, and muscle activity were assessed before, during, and after the stretching. The absolute and relative (i.e., normalized to the static stretching start value) GAS shear elastic modulus relaxation varied across stretching intensities. The absolute passive torque relaxation varied across intensities (p stretching start value. No significant changes were observed in GAS fascicle length during the stretching (p = 0.93). After stretching, passive torque at a given angle was significantly decreased for R60 [-0.99 ± 0.59 Nm (-6.5 ± 3.8 %), p stretching and post-stretching effect in the GAS shear elastic modulus or ankle passive torque variables. No significant relation was found between the shear elastic modulus and the ankle passive torque responses during and after stretching. The effects of stretching on joint passive torque do not reflect changes in the medial gastrocnemius shear elastic modulus, and these responses to stretching depend on its intensity.

  19. Double photoionisation spectra of molecules

    CERN Document Server

    Eland, John

    2017-01-01

    This book contains spectra of the doubly charged positive ions (dications) of some 75 molecules, including the major constituents of terrestrial and planetary atmospheres and prototypes of major chemical groups. It is intended to be a new resource for research in all areas of molecular spectroscopy involving high energy environments, both terrestrial and extra-terrestrial. All the spectra have been produced by photoionisation using laboratory lamps or synchrotron radiation and have been measured using the magnetic bottle time-of-flight technique by coincidence detection of correlated electron pairs. Full references to published work on the same species are given, though for several molecules these are the first published spectra. Double ionisation energies are listed and discussed in relation to the molecular electronic structure of the molecules. A full introduction to the field of molecular double ionisation is included and the mechanisms by which double photoionisation can occur are examined in detail. A p...

  20. Micropatterning stretched and aligned DNA for sequence-specific nanolithography

    Science.gov (United States)

    Petit, Cecilia Anna Paulette

    Techniques for fabricating nanostructured materials can be categorized as either "top-down" or "bottom-up". Top-down techniques use lithography and contact printing to create patterned surfaces and microfluidic channels that can corral and organize nanoscale structures, such as molecules and nanorods in contrast; bottom-up techniques use self-assembly or molecular recognition to direct the organization of materials. A central goal in nanotechnology is the integration of bottom-up and top-down assembly strategies for materials development, device design; and process integration. With this goal in mind, we have developed strategies that will allow this integration by using DNA as a template for nanofabrication; two top-down approaches allow the placement of these templates, while the bottom-up technique uses the specific sequence of bases to pattern materials along each strand of DNA. Our first top-down approach, termed combing of molecules in microchannels (COMMIC), produces microscopic patterns of stretched and aligned molecules of DNA on surfaces. This process consists of passing an air-water interface over end adsorbed molecules inside microfabricated channels. The geometry of the microchannel directs the placement of the DNA molecules, while the geometry of the airwater interface directs the local orientation and curvature of the molecules. We developed another top-down strategy for creating micropatterns of stretched and aligned DNA using surface chemistry. Because DNA stretching occurs on hydrophobic surfaces, this technique uses photolithography to pattern vinyl-terminated silanes on glass When these surface-, are immersed in DNA solution, molecules adhere preferentially to the silanized areas. This approach has also proven useful in patterning protein for cell adhesion studies. Finally, we describe the use of these stretched and aligned molecules of DNA as templates for the subsequent bottom-up construction of hetero-structures through hybridization

  1. Far IR spectra of Th(IV) halide complexes of some heterocyclic bases

    International Nuclear Information System (INIS)

    Srivastava, A.K.; Agarwal, R.K.; Srivastava, M.; Kapoor, V.; Srivastava, T.N.

    1981-01-01

    The synthesis and IR spectra of Th(IV) perchlorato, nitrato and thiocyanato complexes of some heterocyclic bases have been reported. Halogens are common ligands in coordination chemistry forming coordinate bonds with metals readily. Metal halogen (M-X) stretching bands show a strong absorption in the far-IR region. Very little information is available on Th-X stretching frequencies. In the present communication, adducts of Th(IV) halide with certain nitrogen heterocyclic bases such as pyridine, α-picoline, 2-amino pyridine, 2:4-lutidine, 2:6-lutidine, quinoline, 2,2'-bipyridine and 1,10-phenanthroline were synthesised and characterised. Experimental details are given. Results are presented and discussed. (author)

  2. Short Term Effects of Neurodynamic Stretching and Static Stretching Techniques on Hamstring Muscle Flexibility in Healthy Male Subjects

    OpenAIRE

    Adel Rashad Ahmed; Ahmed Fathy Samhan

    2016-01-01

    Flexibility is a key component of rehabilitation and inadequate muscle extensibility remains a commonly accepted factor for musculoskeletal disorders. Studies on the most optimal technique for improving muscle flexibility are a widely debated. The aim of the study was to compare the effectiveness of neurodynamic and static stretching techniques on hamstring flexibility in healthy male subjects. This study was a randomized experimental trial; forty healthy male subjects with hamstr...

  3. Effects of Dynamic and Static Stretching Within General and Activity Specific Warm-Up Protocols

    OpenAIRE

    Samson, Michael; Button, Duane C.; Chaouachi, Anis; Behm, David G.

    2012-01-01

    The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1) general aerobic warm-up with static stretching, 2) general aerobic warm-up with dynamic stretching, 3) general and specific warm-up with static stretching and 4) general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested...

  4. A simple constrained uniaxial tensile apparatus for in situ investigation of film stretching processing.

    Science.gov (United States)

    Meng, Lingpu; Li, Jing; Cui, Kunpeng; Chen, Xiaowei; Lin, Yuanfei; Xu, Jiali; Li, Liangbin

    2013-11-01

    A simple constrained uniaxial tensile apparatus was designed and constructed to obtain stress-strain curve during stretching and subsequent structural evolution of polymeric films. Stretch is carried out through two motor driven clamps in the machine direction and scissor-like clamps in the transverse direction keeping the sample width constant. The force information during film stretching process is recorded by a tension sensor and structural evolution can be obtained by in situ X-ray scattering technique. All parameters related to film stretching manufacturing, such as temperature, draw ratio, and stretching speed can be set independently, making the apparatus an effective method to explore the relationship between processing parameters and structure.

  5. Automatic identification of mass spectra

    International Nuclear Information System (INIS)

    Drabloes, F.

    1992-01-01

    Several approaches to preprocessing and comparison of low resolution mass spectra have been evaluated by various test methods related to library search. It is shown that there is a clear correlation between the nature of any contamination of a spectrum, the basic principle of the transformation or distance measure, and the performance of the identification system. The identification of functionality from low resolution spectra has also been evaluated using several classification methods. It is shown that there is an upper limit to the success of this approach, but also that this can be improved significantly by using a very limited amount of additional information. 10 refs

  6. Correlation Functions and Power Spectra

    DEFF Research Database (Denmark)

    Larsen, Jan

    2006-01-01

    The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions....... It is possible to define correlation functions and associated spectra for aperiodic, periodic and random signals although the interpretation is different. Moreover, we will discuss correlation functions when mixing these basic signal types. In addition, the note include several examples for the purpose...

  7. Matrix infrared spectra and electronic structure calculations of the first actinide borylene: FB=ThF(2).

    Science.gov (United States)

    Wang, Xuefeng; Roos, Björn O; Andrews, Lester

    2010-03-14

    Laser-ablated Th atoms react with BF(3) during condensation in excess argon at 6 K to form the first actinide borylene (FB=ThF(2)) and actinide-boron multiple bond. Three new product absorptions in the B-F and Th-F stretching regions of matrix infrared spectra are assigned to FB=ThF(2) from comparison to theoretically predicted vibrational frequencies.

  8. FT-Raman spectra of cellulose and lignocellulose materials : “self-absorption” phenomenon and its implications for quantitative work

    Science.gov (United States)

    Umesh Agarwal; Nancy Kawai

    2003-01-01

    The phenomenon of “self-absorption” was found to exist in the FT-Raman spectra of cellulose and thermomechanical pulp (TMP), but not in the spectrum of milled wood lignin. For cellulose and TMP, the effect was responsible for reducing the intensity of the Raman bands in the C-H stretch region. Several factors including sampling position, sample thickness, and moisture...

  9. Time course of the effects of static stretching on cycling economy.

    Science.gov (United States)

    Wolfe, Alyson E; Brown, Lee E; Coburn, Jared W; Kersey, Robert D; Bottaro, Martim

    2011-11-01

    Stretching has been implemented as part of the warm-up before physical events and widely thought to promote increased sport performance and decreased injury risk. However, recent research has concluded that static stretching before many exercises inhibits acute power, strength, and sprinting performance. There is little research examining the time course of these effects on moderate intensity cycling. The purpose of this study was to examine the time course of static stretching on cycling economy. The subjects consisted of 5 men and 5 women highly trained endurance cyclists. The first of 3 visits was baseline testing of their cycling VO2max. The second and third visits were either stretching or no stretching before a 30-minute stationary ride at 65% of their VO2max. The stretching condition consisted of four 30-second repetitions of 5 stretches with an average total stretching time of 16 minutes. VO2 demonstrated a significant condition by time interaction with the 5-minute time point being significantly less in the nonstretching condition (32.66 ± 5.35 ml·kg(-1)·min(-1)) than stretching (34.39 ± 5.39 ml·kg(-1)·min(-1)). No other time points were different. Our results demonstrate that static stretching yielded an acute increase in submaximal VO2; therefore, coaches and highly trained endurance cyclists should exclude static stretching immediately before moderate intensity cycling because it reduces acute cycling economy.

  10. Mechanical stretching for tissue engineering: two-dimensional and three-dimensional constructs.

    Science.gov (United States)

    Riehl, Brandon D; Park, Jae-Hong; Kwon, Il Keun; Lim, Jung Yul

    2012-08-01

    Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.

  11. Magnitude-dependent proliferation and contractility modulation of human bladder smooth muscle cells under physiological stretch.

    Science.gov (United States)

    Luo, De-Yi; Wazir, Romel; Du, Caigan; Tian, Ye; Yue, Xuan; Wei, Tang-Qiang; Wang, Kun-Jie

    2015-11-01

    The purpose of this study was to describe and test a kind of stretch pattern which is based on modified BOSE BioDynamic system to produce optimum physiological stretch during bladder cycle. Moreover, we aimed to emphasize the effects of physiological stretch's amplitude upon proliferation and contractility of human bladder smooth muscle cells (HBSMCs). HBSMCs were seeded onto silicone membrane and subjected to stretch simulating bladder cycle at the range of stretches and time according to customized software on modified BOSE BioDynamic bioreactor. Morphological changes were assessed using immunofluorescence and confocal laser scanning microscope. Cell proliferation and cell viability were determined by BrdU incorporation assay and Cell Counting Kit-8, respectively. Contractility of the cells was determined using collagen gel contraction assay. RT-PCR was used to assess phenotypic and contractility markers. HBSMCs were found to show morphologically spindle-shaped and orientation at various elongations in the modified bioreactor. Stretch-induced proliferation and viability depended on the magnitude of stretch, and stretches also regulate contractility and contraction markers in a magnitude-dependent manner. We described and tested a kind of stretch pattern which delivers physiological stretch implemented during bladder cycle. The findings also showed that mechanical stretch can promote magnitude-dependent morphological, proliferative and contractile modulation of HBSMCs in vitro.

  12. Possible Cause of Nonlinear Tension Rise in Activated Muscle Fiber during Stretching.

    Science.gov (United States)

    Kochubei, P V; Bershitsky, S Yu

    2016-11-01

    Tension in contracting muscle fiber under conditions of ramp stretching rapidly increases, but after reaching a critical stretch P c sharply decreases. To find out the cause of these changes in muscle fiber tension, we stopped stretching before and after reaching P c and left the fiber stretched for 50 msec. After rapid tension drop, the transient tension rise not accompanied by fiber stiffness increase was observed only in fibers heated to 25°C and stretched to P c . Under other experimental conditions, this growth was absent. We suppose that stretch of the fiber to P c induces transition of stereo-specifically attached myosin heads to pre-power stroke state and when the stretching is stopped, they make their step on actin and generate force. When the tension reaches P c , all stereospecifically attached myosin heads turn out to be non-stereospecifically, or weakly attached to actin, and are unable to make the force-generating step.

  13. Fluorescence Spectra of Highlighter Inks

    Science.gov (United States)

    Birriel, Jennifer J.; King, Damon

    2018-01-01

    Fluorescence spectra excited by laser pointers have been the subject of several papers in "TPT". These papers all describe a fluorescence phenomenon in which the reflected laser light undergoes a change in color: this color change results from the combination of some partially reflected laser light and additional colors generated by…

  14. Classical Trajectories and Quantum Spectra

    Science.gov (United States)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  15. Explanation of earthquake response spectra

    OpenAIRE

    Douglas, John

    2017-01-01

    This is a set of five slides explaining how earthquake response spectra are derived from strong-motion records and simple models of structures and their purpose within seismic design and assessment. It dates from about 2002 and I have used it in various introductory lectures on engineering seismology.

  16. Lamellar thickness and stretching temperature dependency of cavitation in semicrystalline polymers.

    Directory of Open Access Journals (Sweden)

    Yaotao Wang

    Full Text Available Polybutene-1 (PB-1, a typical semicrystalline polymer, in its stable form I shows a peculiar temperature dependent strain-whitening behavior when being stretched at temperatures in between room temperature and melting temperature of the crystallites where the extent of strain-whitening weakens with the increasing of stretching temperature reaching a minima value followed by an increase at higher stretching temperatures. Correspondingly, a stronger strain-hardening phenomenon was observed at higher temperatures. The strain-whitening phenomenon in semicrystalline polymers has its origin of cavitation process during stretching. In this work, the effect of crystalline lamellar thickness and stretching temperature on the cavitation process in PB-1 has been investigated by means of combined synchrotron ultrasmall-angle and wide-angle X-ray scattering techniques. Three modes of cavitation during the stretching process can be identified, namely "no cavitation" for the quenched sample with the thinnest lamellae where only shear yielding occurred, "cavitation with reorientation" for the samples stretched at lower temperatures and samples with thicker lamellae, and "cavitation without reorientation" for samples with thinner lamellae stretched at higher temperatures. The mode "cavitation with reorientation" occurs before yield point where the plate-like cavities start to be generated within the lamellar stacks with normal perpendicular to the stretching direction due to the blocky substructure of the crystalline lamellae and reorient gradually to the stretching direction after strain-hardening. The mode of "cavitation without reorientation" appears after yield point where ellipsoidal shaped cavities are generated in those lamellae stacks with normal parallel to the stretching direction followed by an improvement of their orientation at larger strains. X-ray diffraction results reveal a much improved crystalline orientation for samples with thinner lamellae

  17. Lamellar thickness and stretching temperature dependency of cavitation in semicrystalline polymers.

    Science.gov (United States)

    Wang, Yaotao; Jiang, Zhiyong; Fu, Lianlian; Lu, Ying; Men, Yongfeng

    2014-01-01

    Polybutene-1 (PB-1), a typical semicrystalline polymer, in its stable form I shows a peculiar temperature dependent strain-whitening behavior when being stretched at temperatures in between room temperature and melting temperature of the crystallites where the extent of strain-whitening weakens with the increasing of stretching temperature reaching a minima value followed by an increase at higher stretching temperatures. Correspondingly, a stronger strain-hardening phenomenon was observed at higher temperatures. The strain-whitening phenomenon in semicrystalline polymers has its origin of cavitation process during stretching. In this work, the effect of crystalline lamellar thickness and stretching temperature on the cavitation process in PB-1 has been investigated by means of combined synchrotron ultrasmall-angle and wide-angle X-ray scattering techniques. Three modes of cavitation during the stretching process can be identified, namely "no cavitation" for the quenched sample with the thinnest lamellae where only shear yielding occurred, "cavitation with reorientation" for the samples stretched at lower temperatures and samples with thicker lamellae, and "cavitation without reorientation" for samples with thinner lamellae stretched at higher temperatures. The mode "cavitation with reorientation" occurs before yield point where the plate-like cavities start to be generated within the lamellar stacks with normal perpendicular to the stretching direction due to the blocky substructure of the crystalline lamellae and reorient gradually to the stretching direction after strain-hardening. The mode of "cavitation without reorientation" appears after yield point where ellipsoidal shaped cavities are generated in those lamellae stacks with normal parallel to the stretching direction followed by an improvement of their orientation at larger strains. X-ray diffraction results reveal a much improved crystalline orientation for samples with thinner lamellae stretched at higher

  18. Cyclic stretch-induced stress fiber dynamics - Dependence on strain rate, Rho-kinase and MLCK

    International Nuclear Information System (INIS)

    Lee, Chin-Fu; Haase, Candice; Deguchi, Shinji; Kaunas, Roland

    2010-01-01

    Research highlights: → Cyclic stretch induces stress fiber disassembly, reassembly and fusion perpendicular to the direction of stretch. → Stress fiber disassembly and reorientation were not induced at low stretch frequency. → Stretch caused actin fiber formation parallel to stretch in distinct locations in cells treated with Rho-kinase and MLCK inhibitors. -- Abstract: Stress fiber realignment is an important adaptive response to cyclic stretch for nonmuscle cells, but the mechanism by which such reorganization occurs is not known. By analyzing stress fiber dynamics using live cell microscopy, we revealed that stress fiber reorientation perpendicular to the direction of cyclic uniaxial stretching at 1 Hz did not involve disassembly of the stress fiber distal ends located at focal adhesion sites. Instead, these distal ends were often used to assemble new stress fibers oriented progressively further away from the direction of stretch. Stress fiber disassembly and reorientation were not induced when the frequency of stretch was decreased to 0.01 Hz, however. Treatment with the Rho-kinase inhibitor (Y27632) reduced stress fibers to thin fibers located in the cell periphery which bundled together to form thick fibers oriented parallel to the direction of stretching at 1 Hz. In contrast, these thin fibers remained diffuse in cells subjected to stretch at 0.01 Hz. Cyclic stretch at 1 Hz also induced actin fiber formation parallel to the direction of stretch in cells treated with the myosin light chain kinase (MLCK) inhibitor ML-7, but these fibers were located centrally rather than peripherally. These results shed new light on the mechanism by which stress fibers reorient in response to cyclic stretch in different regions of the actin cytoskeleton.

  19. Intermittent But Not Continuous Static Stretching Improves Subsequent Vertical Jump Performance In Flexibility-Trained Athletes.

    Science.gov (United States)

    Bogdanis, Gregory C; Donti, Olyvia; Tsolakis, Charilaos; Smilios, Ilias; Bishop, David J

    2017-02-23

    This study examined changes in countermovement jump (CMJ) height after an intermittent or a continuous static stretching protocol of equal total duration. Sixteen male, elite-level gymnasts performed 90 s of intermittent (3 x 30 s with 30 s rest) or continuous stretching (90 s) of the quadriceps muscle. A single-leg stretching and jumping design was used, with the contra-lateral limb serving as a control. The same individuals performed both conditions with alternate legs in a randomized, counterbalanced order. One leg CMJ height was measured for the stretched and the control leg after warm-up, immediately after stretching, and at regular intervals for 10 min after stretching. Range of motion (ROM) of the hip and knee joints was measured before, after, and 10 min post-stretching. Compared to the control leg, intermittent stretching increased CMJ height by 8.1±2.0%, 4 min into recovery (+2.2±2.0 cm, 95%CI: 1.0-3.4 cm, p=0.001), while continuous stretching decreased CMJ height by 17.5±3.3% immediately after (-2.9±1.7 cm, 95%CI: -2.0 to -3.7 cm, p=0.001) and by 12.0±2.7% one min after stretching (-2.2±2.1 cm, 95%CI: -1.2 to -3.2 cm, p=0.001). The increases in hip (2.9 and 3.6, p=0.001. d=2.4) and knee joint ROM (5.1 and 6.1, p=0.001. d=0.85) after the intermittent and continuous stretching protocols were not different. The opposite effects of intermittent vs. continuous stretching on subsequent CMJ performance suggests that stretching mode is an important variable when examining the acute effects of static stretching on performance in flexibility-trained athletes.

  20. Improved Resolution Optical Time Stretch Imaging Based on High Efficiency In-Fiber Diffraction.

    Science.gov (United States)

    Wang, Guoqing; Yan, Zhijun; Yang, Lei; Zhang, Lin; Wang, Chao

    2018-01-12

    Most overlooked challenges in ultrafast optical time stretch imaging (OTSI) are sacrificed spatial resolution and higher optical loss. These challenges are originated from optical diffraction devices used in OTSI, which encode image into spectra of ultrashort optical pulses. Conventional free-space diffraction gratings, as widely used in existing OTSI systems, suffer from several inherent drawbacks: limited diffraction efficiency in a non-Littrow configuration due to inherent zeroth-order reflection, high coupling loss between free-space gratings and optical fibers, bulky footprint, and more importantly, sacrificed imaging resolution due to non-full-aperture illumination for individual wavelengths. Here we report resolution-improved and diffraction-efficient OTSI using in-fiber diffraction for the first time to our knowledge. The key to overcome the existing challenges is a 45° tilted fiber grating (TFG), which serves as a compact in-fiber diffraction device offering improved diffraction efficiency (up to 97%), inherent compatibility with optical fibers, and improved imaging resolution owning to almost full-aperture illumination for all illumination wavelengths. 50 million frames per second imaging of fast moving object at 46 m/s with improved imaging resolution has been demonstrated. This conceptually new in-fiber diffraction design opens the way towards cost-effective, compact and high-resolution OTSI systems for image-based high-throughput detection and measurement.

  1. Potential axillary nerve stretching during RSA implantation: an anatomical study.

    Science.gov (United States)

    Marion, Blandine; Leclère, Franck Marie; Casoli, Vincent; Paganini, Federico; Unglaub, Frank; Spies, Christian; Valenti, Philippe

    2014-09-01

    Clinical and subclinical neurological injury after reverse shoulder arthroplasty (RSA) may jeopardize functional outcomes due to the risk of irreversible damage to the axillary nerve. We proposed a simple anatomical study in order to assess the macroscopic effects on the axillary nerve when lowering the humerus as performed during RSA implantation. We also measured the effect on the axillary nerve of a lateralization of the humerus. Between 2011 and 2012, cadaveric dissections of 16 shoulder specimens from nine fresh human cadavers were performed in order to assess the effects on the axillary nerve after the lowering and lateralization of the humerus. We assessed the extent of stretching of the axillary nerve in four positions in the sagittal plane [lowering of the humerus: great tuberosity in contact with the acromion (position 1), in contact with the upper (position 2), middle (position 3) and lower rim of the glenoid (position 4)] and three positions in the frontal plane [lateralization of the humerus: humerus in contact with the glenoid (position 1), humerus lateralized 1 cm (position 2) and 2 cm (position 3)]. When the humerus was lowered, clear macroscopical changes appeared below the middle of the glenoid (the highest level of tension). As regards the lateralization of the humerus, macroscopic study and measurements confirm the absence of stretching of the nerve in those positions. Lowering of the humerus below the equator of the glenoid changes the course and tension of the axillary nerve and may lead to stretching and irreversible damage, compromising the function of the deltoid. Improvements in the design of the implants and modification of the positioning of the glenosphere to avoid notching and to increase mobility must take into account the anatomical changes induced by the prosthesis and its impact on the brachial plexus. Level of Evidence and study type Level IV.

  2. Elastography Study of Hamstring Behaviors during Passive Stretching

    Science.gov (United States)

    Le Sant, Guillaume; Ates, Filiz; Brasseur, Jean-Louis; Nordez, Antoine

    2015-01-01

    Introduction The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate of changes in muscle-tendon stiffness and passive tension. This study aimed to assess the passive individual behavior of each hamstring muscle in different stretching positions using shear wave elastography. Methods/Results The muscle shear modulus of each hamstring muscle was measured during a standardized slow passive knee extension (PKE, 80% of maximal range of motion) on eighteen healthy male volunteers. Firstly, we assessed the reliability of the measurements. Results were good for semitendinosus (ST, CV: 8.9%-13.4%), semimembranosus (SM, CV: 10.3%-11.2%) and biceps femoris long-head (BF-lh, CV: 8.6%-13.3%), but not for biceps femoris short-head (BF-sh, CV: 20.3%-44.9%). Secondly, we investigated each reliable muscle in three stretch positions: 70°, 90° and 110° of hip flexion. The results showed different values of shear modulus for the same amount of perceived stretch, with the highest measurements in the high-flexed hip situation. Moreover, individual muscles displayed different values, with values increasing or BF-lh, SM and ST, respectively. The inter-subject variability was 35.3% for ST, 27.4% for SM and 30.2% for BF-lh. Conclusion This study showed that the hip needs to be high-flexed to efficiently tension the hamstrings, and reports a higher muscle-tendon stress tolerance at 110° of hip angle. In addition muscles have different passive behaviors, and future works will clarify if it can be linked with rate of injury. PMID:26418862

  3. Elastography Study of Hamstring Behaviors during Passive Stretching.

    Directory of Open Access Journals (Sweden)

    Guillaume Le Sant

    Full Text Available The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate of changes in muscle-tendon stiffness and passive tension. This study aimed to assess the passive individual behavior of each hamstring muscle in different stretching positions using shear wave elastography.The muscle shear modulus of each hamstring muscle was measured during a standardized slow passive knee extension (PKE, 80% of maximal range of motion on eighteen healthy male volunteers. Firstly, we assessed the reliability of the measurements. Results were good for semitendinosus (ST, CV: 8.9%-13.4%, semimembranosus (SM, CV: 10.3%-11.2% and biceps femoris long-head (BF-lh, CV: 8.6%-13.3%, but not for biceps femoris short-head (BF-sh, CV: 20.3%-44.9%. Secondly, we investigated each reliable muscle in three stretch positions: 70°, 90° and 110° of hip flexion. The results showed different values of shear modulus for the same amount of perceived stretch, with the highest measurements in the high-flexed hip situation. Moreover, individual muscles displayed different values, with values increasing or BF-lh, SM and ST, respectively. The inter-subject variability was 35.3% for ST, 27.4% for SM and 30.2% for BF-lh.This study showed that the hip needs to be high-flexed to efficiently tension the hamstrings, and reports a higher muscle-tendon stress tolerance at 110° of hip angle. In addition muscles have different passive behaviors, and future works will clarify if it can be linked with rate of injury.

  4. Resistance training vs. static stretching: effects on flexibility and strength.

    Science.gov (United States)

    Morton, Sam K; Whitehead, James R; Brinkert, Ronald H; Caine, Dennis J

    2011-12-01

    Morton, SK, Whitehead, JR, Brinkert, RH, and Caine, DJ. Resistance training vs. static stretching: Effects on flexibility and strength. J Strength Cond Res 25(12): 3391-3398, 2011-The purpose of this study was to determine how full-range resistance training (RT) affected flexibility and strength compared to static stretching (SS) of the same muscle-joint complexes in untrained adults. Volunteers (n = 25) were randomized to an RT or SS training group. A group of inactive volunteers (n = 12) served as a convenience control group (CON). After pretesting hamstring extension, hip flexion and extension, shoulder extension flexibility, and peak torque of quadriceps and hamstring muscles, subjects completed 5-week SS or RT treatments in which the aim was to stretch or to strength train the same muscle-joint complexes over similar movements and ranges. Posttests of flexibility and strength were then conducted. There was no difference in hamstring flexibility, hip flexion, and hip extension improvement between RT and SS, but both were superior to CON values. There were no differences between groups on shoulder extension flexibility. The RT group was superior to the CON in knee extension peak torque, but there were no differences between groups on knee flexion peak torque. The results of this preliminary study suggest that carefully constructed full-range RT regimens can improve flexibility as well as the typical SS regimens employed in conditioning programs. Because of the potential practical significance of these results to strength and conditioning programs, further studies using true experimental designs, larger sample sizes, and longer training durations should be conducted with the aim of confirming or disproving these results.

  5. Ultrafast quantitative time-stretch imaging flow cytometry of phytoplankton

    Science.gov (United States)

    Lai, Queenie T. K.; Lau, Andy K. S.; Tang, Anson H. L.; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2016-03-01

    Comprehensive quantification of phytoplankton abundance, sizes and other parameters, e.g. biomasses, has been an important, yet daunting task in aquatic sciences and biofuel research. It is primarily because of the lack of effective tool to image and thus accurately profile individual microalgae in a large population. The phytoplankton species are highly diversified and heterogeneous in terms of their sizes and the richness in morphological complexity. This fact makes time-stretch imaging, a new ultrafast real-time optical imaging technology, particularly suitable for ultralarge-scale taxonomic classification of phytoplankton together with quantitative image recognition and analysis. We here demonstrate quantitative imaging flow cytometry of single phytoplankton based on quantitative asymmetric-detection time-stretch optical microscopy (Q-ATOM) - a new time-stretch imaging modality for label-free quantitative phase imaging without interferometric implementations. Sharing the similar concept of Schlieren imaging, Q-ATOM accesses multiple phase-gradient contrasts of each single phytoplankton, from which the quantitative phase profile is computed. We employ such system to capture, at an imaging line-scan rate of 11.6 MHz, high-resolution images of two phytoplankton populations (scenedesmus and chlamydomonas) in ultrafast microfluidic flow (3 m/s). We further perform quantitative taxonomic screening analysis enabled by this technique. More importantly, the system can also generate quantitative phase images of single phytoplankton. This is especially useful for label-free quantification of biomasses (e.g. lipid droplets) of the particular species of interest - an important task adopted in biofuel applications. Combining machine learning for automated classification, Q-ATOM could be an attractive platform for continuous and real-time ultralarge-scale single-phytoplankton analysis.

  6. Computation of nuclear reactor parameters using a stretch Kalman filtering

    International Nuclear Information System (INIS)

    Zwingelstein, G.; Poujol, A.

    1976-01-01

    A method of nonlinear stochastic filtering, the stretched Karman filter, is used for the estimation of two basic parameters involved in the control of nuclear reactor start-up. The corresponding algorithm is stored in a small Multi-8 computer and tested with data recorded for the Ulysse reactor (I.N.S.T.N.). The various practical problems involved in using the algorithm are examined: filtering initialization, influence of the model... The quality and time saving obtained in the computation make it possible for a real time operation, the computer being connected with the reactor [fr

  7. Boundary layer flow of nanofluid over an exponentially stretching surface

    Science.gov (United States)

    Nadeem, Sohail; Lee, Changhoon

    2012-01-01

    The steady boundary layer flow of nanofluid over an exponential stretching surface is investigated analytically. The transport equations include the effects of Brownian motion parameter and thermophoresis parameter. The highly nonlinear coupled partial differential equations are simplified with the help of suitable similarity transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions are obtained by plotting h-curve. The expressions for velocity, temperature and nanoparticle volume fraction are computed for some values of the parameters namely, suction injection parameter α, Lewis number Le, the Brownian motion parameter Nb and thermophoresis parameter Nt.

  8. Boundary layer flow of nanofluid over an exponentially stretching surface.

    Science.gov (United States)

    Nadeem, Sohail; Lee, Changhoon

    2012-01-30

    The steady boundary layer flow of nanofluid over an exponential stretching surface is investigated analytically. The transport equations include the effects of Brownian motion parameter and thermophoresis parameter. The highly nonlinear coupled partial differential equations are simplified with the help of suitable similarity transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions are obtained by plotting h-curve. The expressions for velocity, temperature and nanoparticle volume fraction are computed for some values of the parameters namely, suction injection parameter α, Lewis number Le, the Brownian motion parameter Nb and thermophoresis parameter Nt.

  9. An energetic model for macromolecules unfolding in stretching experiments

    Science.gov (United States)

    De Tommasi, D.; Millardi, N.; Puglisi, G.; Saccomandi, G.

    2013-01-01

    We propose a simple approach, based on the minimization of the total (entropic plus unfolding) energy of a two-state system, to describe the unfolding of multi-domain macromolecules (proteins, silks, polysaccharides, nanopolymers). The model is fully analytical and enlightens the role of the different energetic components regulating the unfolding evolution. As an explicit example, we compare the analytical results with a titin atomic force microscopy stretch-induced unfolding experiment showing the ability of the model to quantitatively reproduce the experimental behaviour. In the thermodynamic limit, the sawtooth force–elongation unfolding curve degenerates to a constant force unfolding plateau. PMID:24047874

  10. Duration of static stretching influences muscle force production in hamstring muscles.

    Science.gov (United States)

    Ogura, Yuji; Miyahara, Yutetsu; Naito, Hisashi; Katamoto, Shizuo; Aoki, Junichiro

    2007-08-01

    The purpose of the present study was to investigate whether duration of static stretching could affect the maximal voluntary contraction (MVC). Volunteer male subjects (n = 10) underwent 2 different durations of static stretching of their hamstring muscles in the dominant leg: 30 and 60 seconds. No static stretching condition was used as a control condition. Before and after each stretching trial, hamstring flexibility was measured by a sit and reach test. MVC was then measured using the maximal effort of knee flexion. The hamstring flexibility was significantly increased by 30 and 60 seconds of static stretching (control: 0.5 +/- 1.1 cm; 30 seconds: 2.1 +/- 1.8 cm; 60 seconds: 3.0 +/- 1.6 cm); however, there was no significant difference between 30 and 60 seconds of static stretching conditions. The MVC was significantly lowered with 60 seconds of static stretching compared to the control and 30 seconds of the stretching conditions (control: 287.6 +/- 24.0 N; 30 seconds: 281.8 +/- 24.2 N; 60 seconds: 262.4 +/- 36.2 N). However, there was no significant difference between control and 30 seconds of static stretching conditions. Therefore, it was concluded that the short duration (30 seconds) of static stretching did not have a negative effect on the muscle force production.

  11. Acute effects of static, dynamic, and proprioceptive neuromuscular facilitation stretching on muscle power in women.

    Science.gov (United States)

    Manoel, Mateus E; Harris-Love, Michael O; Danoff, Jerome V; Miller, Todd A

    2008-09-01

    The purpose of this study was to investigate the acute effects of 3 types of stretching-static, dynamic, and proprioceptive neuromuscular facilitation (PNF)-on peak muscle power output in women. Concentric knee extension power was measured isokinetically at 60 degrees x s(-1) and 180 degrees x s(-1) in 12 healthy and recreationally active women (mean age +/- SD, 24 +/- 3.3 years). Testing occurred before and after each of 3 different stretching protocols and a control condition in which no stretching was performed. During 4 separate laboratory visits, each subject performed 5 minutes of stationary cycling at 50 W before performing the control condition, static stretching protocol, dynamic stretching protocol, or PNF protocol. Three submaximal warm-up trials preceded 3 maximal knee extensions at each testing velocity. A 2-minute rest was allowed between testing at each velocity. The results of the statistical analysis indicated that none of the stretching protocols caused a decrease in knee extension power. Dynamic stretching produced percentage increases (8.9% at 60 degrees x s(-1) and 6.3% at 180 degrees x s(-1)) in peak knee extension power at both testing velocities that were greater than changes in power after static and PNF stretching. The findings suggest that dynamic stretching may increase acute muscular power to a greater degree than static and PNF stretching. These findings may have important implications for athletes who participate in events that rely on a high level of muscular power.

  12. The effect of static, ballistic, and proprioceptive neuromuscular facilitation stretching on vertical jump performance.

    Science.gov (United States)

    Bradley, Paul S; Olsen, Peter D; Portas, Matthew D

    2007-02-01

    The purpose of this study was to compare the acute effects of different modes of stretching on vertical jump performance. Eighteen male university students (age, 24.3 +/- 3.2 years; height, 181.5 +/- 11.4 cm; body mass, 78.1 +/- 6.4 kg; mean +/- SD) completed 4 different conditions in a randomized order, on different days, interspersed by a minimum of 72 hours of rest. Each session consisted of a standard 5-minute cycle warm-up, accompanied by one of the subsequent conditions: (a) control, (b) 10-minute static stretching, (c) 10-minute ballistic stretching, or (d) 10-minute proprioceptive neuromuscular facilitation (PNF) stretching. The subjects performed 3 trials of static and countermovement jumps prior to stretching and poststretching at 5, 15, 30, 45, and 60 minutes. Vertical jump height decreased after static and PNF stretching (4.0% and 5.1%, p 0.05). However, jumping performance had fully recovered 15 minutes after all stretching conditions. In conclusion, vertical jump performance is diminished for 15 minutes if performed after static or PNF stretching, whereas ballistic stretching has little effect on jumping performance. Consequently, PNF or static stretching should not be performed immediately prior to an explosive athletic movement.

  13. Static stretching does not alter pre and post-landing muscle activation

    Directory of Open Access Journals (Sweden)

    Moss Wesley R

    2011-05-01

    Full Text Available Abstract Background Static stretching may result in various strength and power deficiencies. Prior research has not determined, however, if static stretching causes a change in muscle activation during a functional task requiring dynamic stability. The purpose of this study was to determine if static stretching has an effect on mean pre and postlanding muscle (vastus medialis VM, vastus lateralis VL, medial hamstring MH, and biceps femoris BF activity. Methods 26 healthy, physically active subjects were recruited, from which 13 completed a 14-day static stretching regimen for the quadriceps and hamstrings. Using the data from the force plate and EMG readings, a mean of EMG amplitude was calculated for 150 msec before and after landing. Each trial was normalized to an isometric reference position. Means were calculated for the VM, VL, MH, and BF from 5 trials in each session. Measures were collected pre, immediately following the 1st stretching session, and following 2 weeks of stretching. Results A 14-day static stretching regimen resulted in no significant differences in pre or postlanding mean EMG amplitude during a drop landing either acutely or over a 14-day period. Conclusions Static stretching, done acutely or over a 14-day period does not result in measurable differences of mean EMG amplitude during a drop landing. Static stretching may not impede dynamic stability of joints about which stretched muscles cross.

  14. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength.

    Science.gov (United States)

    Bacurau, Reury Frank Pereira; Monteiro, Gizele Assis; Ugrinowitsch, Carlos; Tricoli, Valmor; Cabral, Leonardo Ferreira; Aoki, Marcelo Saldanha

    2009-01-01

    Different stretching techniques have been used during warm-up routines. However, these routines may decrease force production. The purpose of this study was to compare the acute effect of a ballistic and a static stretching protocol on lower-limb maximal strength. Fourteen physically active women (169.3 +/- 8.2 cm; 64.9 +/- 5.9 kg; 23.1 +/- 3.6 years) performed three experimental sessions: a control session (estimation of 45 degrees leg press one-repetition maximum [1RM]), a ballistic session (20 minutes of ballistic stretch and 45 degrees leg press 1RM), and a static session (20 minutes of static stretch and 45 degrees leg press 1RM). Maximal strength decreased after static stretching (213.2 +/- 36.1 to 184.6 +/- 28.9 kg), but it was unaffected by ballistic stretching (208.4 +/- 34.8 kg). In addition, static stretching exercises produce a greater acute improvement in flexibility compared with ballistic stretching exercises. Consequently, static stretching may not be recommended before athletic events or physical activities that require high levels of force. On the other hand, ballistic stretching could be more appropriate because it seems less likely to decrease maximal strength.

  15. Reconstruction of neutron spectra through neural networks

    International Nuclear Information System (INIS)

    Vega C, H.R.; Hernandez D, V.M.; Manzanares A, E.

    2003-01-01

    A neural network has been used to reconstruct the neutron spectra starting from the counting rates of the detectors of the Bonner sphere spectrophotometric system. A group of 56 neutron spectra was selected to calculate the counting rates that would produce in a Bonner sphere system, with these data and the spectra it was trained the neural network. To prove the performance of the net, 12 spectra were used, 6 were taken of the group used for the training, 3 were obtained of mathematical functions and those other 3 correspond to real spectra. When comparing the original spectra of those reconstructed by the net we find that our net has a poor performance when reconstructing monoenergetic spectra, this attributes it to those characteristic of the spectra used for the training of the neural network, however for the other groups of spectra the results of the net are appropriate with the prospective ones. (Author)

  16. Inclusive spectra in hard processes

    International Nuclear Information System (INIS)

    Kiselev, A.V.; Petrov, V.A.

    1985-01-01

    It is shown that the unified mechanism of hadronization in hard processes results in universality of inclusive spectra of soft hadrons. Inclusive spectrum of hadrons in energy share in deep-inelastic lepton-hadron scattering is calculated. The spectrum obtained is calculated with analogous distribution in e + e - annihilation. It is noted that inclusive spectrum of soft hadrons in hard processes is described by a universal function

  17. ACCELERATED FITTING OF STELLAR SPECTRA

    International Nuclear Information System (INIS)

    Ting, Yuan-Sen; Conroy, Charlie; Rix, Hans-Walter

    2016-01-01

    Stellar spectra are often modeled and fitted by interpolating within a rectilinear grid of synthetic spectra to derive the stars’ labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of labels separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach—Convex Hull Adaptive Tessellation (chat)—which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock data sets demonstrate that chat can reduce the number of required synthetic model calculations by three orders of magnitude in an eight-dimensional label space. The reduction will be even larger for higher dimensional label spaces. In chat the computational effort increases only linearly with the number of labels that are fit simultaneously. Around each of these grid points in the label space an approximate synthetic spectrum can be generated through linear expansion using a set of “gradient spectra” that represent flux derivatives at every wavelength point with respect to all labels. These techniques provide new opportunities to fit the full stellar spectra from large surveys with 15–30 labels simultaneously.

  18. Resonance Raman spectra of metal halide vapor complexes

    International Nuclear Information System (INIS)

    Paptheodorou, G.N.

    1978-01-01

    Resonance Raman spectra of complex vapor phase compounds formed by reacting ''acidic'' gases (A 2 X 6 = Al 2 Cl 6 , Al 2 Br 6 , In 2 Cl 6 ) with metal halides have been measured. Spectra obtained from equilibrium vapor mixtures of A 2 X 6 over solid MX 2 (= PdCl 2 , PdBr 2 , CuCl 2 , CoBr 2 , TiCl 2 , FeCl 2 , NiCl 2 , PtCl 2 ) were a superposition of the A 2 X 6 -AX 3 bands and in few cases of new resonance-enhanced polarized bands due to MA 2 X 8 and/or MAX 5 complexes. At temperatures above 800 0 K, characteristic bands due to MX 2 (g) (M = Fe, Co, Ni, Cu, Zn) and M 2 X 4 (g) (M = Cu) were observed. The predominant features of the PdAl 2 Cl 8 , CuAl 2 Cl 8 , and PdAl 2 Br 6 spectra were three high-intensity, polarized bands which were attributed to the vibrational modes of the complex coupled to the electronic state of the central atom. The spectra of CuAlCl 5 (g), CuInCl 5 (g) and Cu 2 Cl 4 (g) species showed resonance enhancement of selective fundamentals which were attributed to vibrational modes of trigonally coordinated Cu(II). Resonance Raman spectra of U 2 Cl 10 (g) and UCl 5 .AlCl 3 (g) were characterized by the presence of a strong band attributed to the U-Cl/sub t/ stretching frequency. Raman band intensity measurements were carried out for the iron(III) chloride vapors and for the vapor complexes of CuAl 2 Cl 8 , CuInCl 5 and UCl 5 .AlCl 3 using different laser powers and frequencies. The measurements suggested increasing spectroscopic temperatures and decomposition of the vapor complexes. The data are discussed in terms of the distribution of vibrational modes and the structure of the vapor species. 22 figs

  19. Stretched exponential relaxation processes in hydrogenated amorphous and polymorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Morigaki, Kazuo [Department of Electrical and Digital-System Engineering, Hiroshima Institute of Technology, Miyake, Saeki-ku, Hiroshima 731-5193 (Japan); Hikita, Harumi [Physics Laboratory, Meikai University, Urayasu, Chiba 279-8550 (Japan)

    2011-09-15

    Stretched exponential relaxation has been observed in various phenomena of hydrogenated amorphous silicon (a-Si:H) and hydrogenated polymorphous silicon (pm-Si:H). As an example, we take light-induced defect creation in a-Si:H and pm-Si:H, in which defect-creation process and defect-annihilation process via hydrogen movement play important roles. We have performed the Monte Carlo simulation for hydrogen movement. Hydrogen movement exhibits anomalous diffusion. In our model of light-induced defect creation in a-Si:H, a pair of two types of dangling bonds, i.e., a normal dangling bond and a hydrogen-related dangling bond, that is a dangling bond having hydrogen in the nearby site, are created under illumination, and hydrogen dissociated from the hydrogen-related dangling bond terminates a normal dangling bond via hydrogen movement. The amorphous network reflects on the dispersive parameter of the stretched exponential function in the light-induced defect creation. We discuss this issue, taking into account the difference in the amorphous network between a-Si:H and pm-Si:H (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. MHD biconvective flow of Powell Eyring nanofluid over stretched surface

    Science.gov (United States)

    Naseem, Faiza; Shafiq, Anum; Zhao, Lifeng; Naseem, Anum

    2017-06-01

    The present work is focused on behavioral characteristics of gyrotactic microorganisms to describe their role in heat and mass transfer in the presence of magnetohydrodynamic (MHD) forces in Powell-Eyring nanofluids. Implications concerning stretching sheet with respect to velocity, temperature, nanoparticle concentration and motile microorganism density were explored to highlight influential parameters. Aim of utilizing microorganisms was primarily to stabilize the nanoparticle suspension due to bioconvection generated by the combined effects of buoyancy forces and magnetic field. Influence of Newtonian heating was also analyzed by taking into account thermophoretic mechanism and Brownian motion effects to insinuate series solutions mediated by homotopy analysis method (HAM). Mathematical model captured the boundary layer regime that explicitly involved contemporary non linear partial differential equations converted into the ordinary differential equations. To depict nanofluid flow characteristics, pertinent parameters namely bioconvection Lewis number Lb, traditional Lewis number Le, bioconvection Péclet number Pe, buoyancy ratio parameter Nr, bioconvection Rayleigh number Rb, thermophoresis parameter Nt, Hartmann number M, Grashof number Gr, and Eckert number Ec were computed and analyzed. Results revealed evidence of hydromagnetic bioconvection for microorganism which was represented by graphs and tables. Our findings further show a significant effect of Newtonian heating over a stretching plate by examining the coefficient values of skin friction, local Nusselt number and the local density number. Comparison was made between Newtonian fluid and Powell-Eyring fluid on velocity field and temperature field. Results are compared of with contemporary studies and our findings are found in excellent agreement with these studies.

  1. Extension by faulting, stretching and magma intrusion in Ethiopia

    Science.gov (United States)

    Bastow, I. D.; Keir, D.

    2012-12-01

    The 2001-2004 Ethiopia Afar Geoscientific Lithospheric Experiment showed that high seismic wavespeed, dense, mafic crustal intrusions exist beneath many zones of Quaternary magmatism in the Main Ethiopian rift, and that crustal thinning is minimal. From these observations, a consensus quickly emerged that extension presently occurs not by ductile stretching and brittle faulting but by magma intrusion. Striking InSAR images and accompanying seismic data from the 2005 Afar diking episode provided further compelling evidence in support of the magma assisted rifting hypothesis. Patterns of mantle seismic anisotropy, constrained by a combination of body and surface-wave analysis showed that melt intrusion likely also plays an important role in accommodating extension at greater depths in the extending plate. Evidence from further north in Afar, however, where crustal thickness decreases abruptly into the Danakil Depression, is not so easily explained by the magma assisted rifting hypothesis. Subsidence of the newly forming margin towards and below sea level, and eruption of voluminous basalt flows, is likely the result of late-stage thinning of the heavily intruded, weakened plate just before the onset of seafloor spreading. Faulting, stretching and magma intrusion are thus each important, but at different times during breakup. Combining, not isolating, these mechanisms of strain in new rifting models and appreciating how plate strength varies during rifting is essential in developing a clearer understanding of the incomplete geological record that documents continental breakup over time.

  2. Tangential stretching rate (TSR) analysis of non premixed reactive flows

    KAUST Repository

    Valorani, Mauro

    2016-10-16

    We discuss how the Tangential stretching rate (TSR) analysis, originally developed and tested for spatially homogeneous systems (batch reactors), is extended to spatially non homogeneous systems. To illustrate the effectiveness of the TSR diagnostics, we study the ignition transient in a non premixed, reaction–diffusion model in the mixture fraction space, whose dependent variables are temperature and mixture composition. The reactive mixture considered is syngas/air. A detailed H2/CO mechanism with 12 species and 33 chemical reactions is employed. We will discuss two cases, one involving only kinetics as a model of front propagation purely driven by spontaneous ignition, the other as a model of deflagration wave involving kinetics/diffusion coupling. We explore different aspects of the system dynamics such as the relative role of diffusion and kinetics, the evolution of kinetic eigenvalues, and of the tangential stretching rates computed by accounting for the combined action of diffusion and kinetics as well for kinetics only. We propose criteria based on the TSR concept which allow to identify the most ignitable conditions and to discriminate between spontaneous ignition and deflagration front.

  3. Analysis of a Stretched Derivative Aircraft with Open Rotor Propulsion

    Science.gov (United States)

    Berton, Jeffrey J.; Hendricks, Eric S.; Haller, William J.; Guynn, Mark D.

    2015-01-01

    Research into advanced, high-speed civil turboprops received significant attention during the 1970s and 1980s when fuel efficiency was the driving focus of U.S. aeronautical research. But when fuel prices declined sharply there was no longer sufficient motivation to continue maturing the technology. Recent volatility in fuel prices and increasing concern for aviation's environmental impact, however, have renewed interest in unducted, open rotor propulsion and revived research by NASA and a number of engine manufacturers. Recently, NASA and General Electric have teamed to conduct several investigations into the performance and noise of an advanced, single-aisle transport with open rotor propulsion. The results of these initial studies indicate open rotor engines have the potential to provide significant reduction in fuel consumption compared to aircraft using turbofan engines with equivalent core technology. In addition, noise analysis of the concept indicates that an open rotor aircraft in the single-aisle transport class would be able to meet current noise regulations with margin. The behavior of derivative open rotor transports is of interest. Heavier, "stretched" derivative aircraft tend to be noisier than their lighter relatives. Of particular importance to the business case for the concept is how the noise margin changes relative to regulatory limits within a family of similar open rotor aircraft. The subject of this report is a performance and noise assessment of a notional, heavier, stretched derivative airplane equipped with throttle-push variants of NASA's initial open rotor engine design.

  4. Harmonics analysis of the photonic time stretch system.

    Science.gov (United States)

    Mei, Yuan; Xu, Boyu; Chi, Hao; Jin, Tao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

    2016-09-10

    Photonic time stretch (PTS) has been intensively investigated in recent decades due to its potential application to ultra-wideband analog-to-digital conversion. A high-speed analog signal can be captured by an electronic analog-to-digital converter (ADC) with the help of the PTS technique, which slows down the speed of signal in the photonic domain. Unfortunately, the process of the time stretch is not linear due to the nonlinear modulation of the electro-optic intensity modulator in the PTS system, which means the undesired harmonics distortion. In this paper, we present an exact analytical model to fully characterize the harmonics generation in the PTS systems for the first time, to the best of our knowledge. We obtain concise and closed-form expressions for all harmonics of the PTS system with either a single-arm Mach-Zehnder modulator (MZM) or a push-pull MZM. The presented model can largely simplify the PTS system design and the system parameters estimation, such as system bandwidth, harmonics power, time-bandwidth product, and dynamic range. The correctness of the mathematic model is verified by the numerical and experimental results.

  5. Intermittent stretching induces fibrosis in denervated rat muscle.

    Science.gov (United States)

    Faturi, Fernanda M; Franco, Rúbia C; Gigo-Benato, Davilene; Turi, Andriette C; Silva-Couto, Marcela A; Messa, Sabrina P; Russo, Thiago L

    2016-01-01

    Stretching (St) has been used for treating denervated muscles. However, its effectiveness and safety claims require further study. Rats were divided into: (1) those with denervated (D) muscles, evaluated 7 or 15 days after sciatic nerve crush injury; (2) those with D muscles submitted to St during 7 or 15 days; and (3) those with normal muscles. Muscle fiber cross-sectional area, serial sarcomere number, sarcomere length, and connective tissue density were measured. MMP-2, MMP-9, TIMP-1, TGF-β1, and myostatin mRNAs were determined by real-time polymerase chain reaction. MMP-2 and MMP-9 activity was evaluated by zymography. Collagen I was localized using immunofluorescence. St did not prevent muscle atrophy due to denervation, but it increased fibrosis and collagen I deposition at day 15. St also upregulated MMP-9 and TGF-β1 gene expressions at day 7, and myostatin at day 15. Stretching denervated muscle does not prevent atrophy, but it increases fibrosis via temporal modulation of TGF-β1/myostatin and MMP-9 cascades. © 2015 Wiley Periodicals, Inc.

  6. Terrestrial analogs for interpretation of infrared spectra from the Martian surface and subsurface: Sulfate, nitrate, carbonate, and phyllosilicate-bearing Atacama Desert soils

    Science.gov (United States)

    Sutter, B.; Dalton, J. B.; Ewing, S. A.; Amundson, R.; McKay, C. P.

    2007-10-01

    Hyperarid (Mars soils have similar sulfate concentrations; possess phyllosilicates (e.g., smectite) and minor carbonate. Nitrate has not been detected on Mars, but its presence has been proposed. The similar compositions of Atacama and Mars soils have prompted the visible-infrared (0.35-25 μm) investigation of Atacama soils as Mars analogs. Results from this work determined the best infrared features for detecting sulfate, nitrate, carbonate, and phyllosilicate on Mars. The fundamental region (>6.5 μm) was not suited for salt and phyllosilicate detection because of overlapping spectra from primary silicates (e.g., feldspar), water and carbon dioxide. The visible near-infrared (0.35-2.5 μm) region was suited for detecting carbonate, nitrate, gypsum water of hydration, and phyllosilicate hydroxyls without interference from primary silicates. However, gypsum water of hydration features can obscure phyllosilicate hydroxyl, carbonate and nitrate, features if gypsum levels are high. Overtone/combination absorption features in the midinfrared were determined to be the best indicators of sulfate (4.48-4.70 μm), nitrate (4.12 μm), and carbonate (3.98 μm) because interferences from overlapping primary silicate and water features are not present in this region. Interferences from CO2 and thermal emission effects in the overtone/combination region are possible but may be minimized by corrective techniques. Infrared analysis of Atacama Desert soils can provide insight into the spectral search of sulfate, nitrate, carbonate, and phyllosilicate containing soils on Mars.

  7. FTIR, FT-Raman, UV-Visible spectra and quantum chemical calculations of allantoin molecule and its hydrogen bonded dimers.

    Science.gov (United States)

    Alam, Mohammad Jane; Ahmad, Shabbir

    2015-02-05

    FTIR, FT-Raman and electronic spectra of allantoin molecule are recorded and investigated using DFT and MP2 methods with 6-311++G(d,p) basis set. The molecular structure, anharmonic vibrational spectra, natural atomic charges, non-linear optical properties, etc. have been computed for the ground state of allantoin. The anharmonic vibrational frequencies are calculated using PT2 algorithm (Barone method) as well as VSCF and CC-VSCF methods. These methods yield results that are in remarkable agreement with the experiment. The coupling strengths between pairs of modes are also calculated using coupling integral based on 2MR-QFF approximation. The simulations on allantoin dimers have been also performed at B3LYP/6-311++G(d,p) level of theory to investigate the effect of the intermolecular interactions on the molecular structure and vibrational frequencies of the monomer. Vibrational assignments are made with the great accuracy using PED calculations and animated modes. The combination and overtone bands have been also identified in the FTIR spectrum with the help of anharmonic computations. The electronic spectra are simulated in gas and solution at TD-B3LYP/6-311++G(d,p) level of theory. The important global quantities such as electro-negativity, electronic chemical potential, electrophilicity index, chemical hardness and softness based on HOMO, LUMO energy eigenvalues are also computed. NBO analysis has been performed for monomer and dimers of allantoin at B3LYP/6-311++G(d,p) level of theory. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Acute Effects of the Different Intensity of Static Stretching on Flexibility and Isometric Muscle Force.

    Science.gov (United States)

    Kataura, Satoshi; Suzuki, Shigeyuki; Matsuo, Shingo; Hatano, Genki; Iwata, Masahiro; Yokoi, Kazuaki; Tsuchida, Wakako; Banno, Yasuhiro; Asai, Yuji

    2017-12-01

    Kataura, S, Suzuki, S, Matsuo, S, Hatano, G, Iwata, M, Yokoi, K, Tsuchida, W, Banno, Y, and Asai, Y. Acute effects of the different intensity of static stretching on flexibility and isometric muscle force. J Strength Cond Res 31(12): 3403-3410, 2017-In various fields, static stretching is commonly performed to improve flexibility, whereas the acute effects of different stretch intensities are unclear. Therefore, we investigated the acute effects of different stretch intensities on flexibility and muscle force. Eighteen healthy participants (9 men and 9 women) performed 180-second static stretches of the right hamstrings at 80, 100, and 120% of maximum tolerable intensity without stretching pain, in random order. The following outcomes were assessed as markers of lower limb function and flexibility: static passive torque (SPT), range of motion (ROM), passive joint (muscle-tendon) stiffness, passive torque (PT) at onset of pain, and isometric muscle force. Static passive torque was significantly decreased after all stretching intensities (p ≤ 0.05). Compared with before stretching at 100 and 120% intensities, ROM and PT were significantly increased after stretching (p ≤ 0.05), and passive stiffness (p = 0.05) and isometric muscle force (p ≤ 0.05) were significantly decreased. In addition, ROM was significantly greater after stretching at 100 and 120% than at 80%, and passive stiffness was significantly lower after 120% than after 80% (p ≤ 0.05). However, all measurements except SPT were unchanged after 80% intensity. There was a weak positive correlation between the intensities of stretching and the relative change for SPT (p ≤ 0.05), a moderate positive correlation with ROM (p ≤ 0.05), and a moderate positive correlation with passive stiffness (p ≤ 0.05). These results indicate that static stretching at greater intensity is more effective for increasing ROM and decreasing passive muscle-tendon stiffness.

  9. Stretch-induced intussuceptive and sprouting angiogenesis in the chick chorioallantoic membrane

    OpenAIRE

    Belle, Janeil; Ysasi, Alexandra; Bennett, Robert D.; Filipovic, Nenad; Imani Nejad, Mohammad; Trumper, David L.; Ackermann, Maximilian; Wagner, Willi; Tsuda, Akira; Konerding, Moritz A.; Mentzer, Steven J.

    2014-01-01

    Vascular systems grow and remodel in response to not only metabolic needs, but also mechanical influences as well. Here, we investigated the influence of tissue-level mechanical forces on the patterning and structure of the chick chorioallantoic membrane (CAM) microcirculation. A dipole stretch field was applied to the CAM using custom computer-controlled servomotors. The topography of the stretch field was mapped using finite element models. After 3 days of stretch, Sholl analysis of the CAM...

  10. STATIC VERSUS PNF STRETCHING IN HAMSTRING FLEXIBILITY-A COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Venkata Naga Prahalada Karnati

    2015-06-01

    Full Text Available Background: Stretching used as a technique for injury prevention in the clinical settings, the study aimed to determine the early findings of hamstring tightness with both groups in the population, now a days the sedentary activities like prolonged sitting might cause hamstring tightness and change in path kinematics of gait intern lead to postural defects and back pain, understanding of the stretching helps clinician to make decisions for rehabilitation. Methods: Across-sectional study, counterbalanced with repeated-measures , one group with static stretch – (double hamstring stretch and hurdlers stretch for 3 times,30seconds subsequently in another group PNF contract relax(agonist contraction technique for 10 seconds position and 10 seconds stretch repeated for 3 times. Results: The results from data and statistical analysis by using t-test, SPSS obtained by using goniometer are tabulated in terms of mean, standard deviation and p-value in both groups. In experimental group flexion with PNF showed improvement 9.27±1.91(right side, 9.53±2.42(left side and static stretching showed 7.8±2.91(right side, 7.47±1.96(left side this proves that PNF has consistent improvement than static stretching. Conclusions: Static and proprioceptive neuromuscular facilitation stretching both have produced greater improvement but compared with PNF contract relax(agonist stretching showed significant change in hamstring flexibility compared with control group . The effect sizes, however corresponding to these stretching-induced changes were small, which suggests the need for practitioners to consider a risk-to-benefit ratio when incorporating static or proprioceptive neuromuscular facilitation stretching.

  11. Does acute passive stretching increase muscle length in children with cerebral palsy?

    Science.gov (United States)

    Theis, Nicola; Korff, Thomas; Kairon, Harvey; Mohagheghi, Amir A

    2013-01-01

    Children with spastic cerebral palsy experience increased muscle stiffness and reduced muscle length, which may prevent elongation of the muscle during stretch. Stretching performed either by the clinician, or children themselves is used as a treatment modality to increase/maintain joint range of motion. It is not clear whether the associated increases in muscle-tendon unit length are due to increases in muscle or tendon length. The purpose was to determine whether alterations in ankle range of motion in response to acute stretching were accompanied by increases in muscle length, and whether any effects would be dependent upon stretch technique. Eight children (6-14 y) with cerebral palsy received a passive dorsiflexion stretch for 5 × 20 s to each leg, which was applied by a physiotherapist or the children themselves. Maximum dorsiflexion angle, medial gastrocnemius muscle and fascicle lengths, and Achilles tendon length were calculated at a reference angle of 10 ° plantarflexion, and at maximum dorsiflexion in the pre- and post-stretch trials. All variables were significantly greater during pre- and post-stretch trials compared to the resting angle, and were independent of stretch technique. There was an approximate 10 ° increase in maximum dorsiflexion post-stretch, and this was accounted for by elongation of both muscle (0.8 cm) and tendon (1.0 cm). Muscle fascicle length increased significantly (0.6 cm) from pre- to post-stretch. The results provide evidence that commonly used stretching techniques can increase overall muscle, and fascicle lengths immediately post-stretch in children with cerebral palsy. © 2013.

  12. Solving Cracking Phenomenon in Premium Transparent Toilet Soap Production Using Stretched LLDPE Film Wrap

    Science.gov (United States)

    Mat Sharif, Zainon Binti; Taib, Norhasnina Binti Mohd; Yusof, Mohd Sallehuddin Bin; Rahim, Mohammad Zulafif Bin; Tobi, Abdul Latif Bin Mohd; Othman, Mohd Syafiq Bin

    2017-05-01

    Cracking phenomenon in soap production is an imminent problem. It renders the soap aesthetically unpleasing. This study attempts to find best solution to solve cracking phenomenon in premium soap production. The adopted approach is a stamping method with stretched LLDPE wrap film. The result shows that stretched LLDPE wrap film able to solve the cracking problem. The appearance of the premium transparent was improved. This paper presents the results and the SOP for stretched LLDPE film wrap for soap making industries to adopt.

  13. Knee Stretch Walking Method for Biped Robot: Using Toe and Heel Joints to Increase Walking Strides

    Science.gov (United States)

    Sato, Takahiko; Shimmyo, Shuhei; Nakazato, Miki; Mikami, Kei; Sato, Tomoya; Sakaino, Sho; Ohnishi, Kouhei

    This paper proposes a knee stretch walking method for biped robots; the method involves the use of the toes and heel joints to increase walking strides. A knee can be stretched by switching control variables. By a knee stretch walking with heel contacts to the ground and toe takeoffs from the ground, biped robots can increase their walking stride and speed. The validity of the proposed method is confirmed by simulation and experimental results.

  14. High Throughput Web Inspection System using Time-stretch Real-time Imaging

    OpenAIRE

    Kim, Chanju

    2013-01-01

    Photonic time-stretch is a novel technology that enables capturing of fast, rare and non-repetitive events. Therefore, it operates in real-time with ability to record over long period of time while having fine temporal resolution. The powerful property of photonic time-stretch has already been employed in various fields of application such as analog-to-digital conversion, spectroscopy, laser scanner and microscopy. Further expanding the scope, we fully exploit the time-stretch technology to d...

  15. Correlation of the Elastic Properties of Stretch Film on Unit Load Containment

    OpenAIRE

    Bisha, James Victor

    2012-01-01

    The purpose of this research was to correlate the applied material properties of stretch film with its elastic properties measured in a laboratory setting. There are currently no tools available for a packaging engineer to make a scientific decision on how one stretch film performs against another without applying the film. The system for stretch wrap comparison is mostly based on trial and error which can lead to a significant loss of product when testing a new film or shipping a new product...

  16. Duration Dependent Effect of Static Stretching on Quadriceps and Hamstring Muscle Force

    Directory of Open Access Journals (Sweden)

    Leyla Alizadeh Ebadi

    2018-03-01

    Full Text Available The aim of this study was to determine the acute effect of static stretching on hamstring and quadriceps muscles’ isokinetic strength when applied for various durations to elite athletes, to investigate the effect of different static stretching durations on isokinetic strength, and finally to determine the optimal stretching duration. Fifteen elite male athletes from two different sport branches (10 football and five basketball participated in this study. Experimental protocol was designed as 17 repetitive static stretching exercises for hamstring and quadriceps muscle groups according to the indicated experimental protocols; ((A 5 min jogging; (B 5 min jogging followed by 15 s static stretching; (C 5 min jogging followed by 30 s static stretching; (D 5 min jogging, followed by static stretching for 45 s. Immediately after each protocol, an isokinetic strength test consisting of five repetitions at 60°/s speed and 20 repetitions at 180°/s speed was recorded for the right leg by the Isomed 2000 device. Friedman variance analysis test was employed for data analysis. According to the analyzes, it was observed that 5 min jogging and 15 s stretching exercises increased the isokinetic strength, whereas 30 and 45 s stretching exercises caused a decrease.

  17. EFFECTS OF DYNAMIC AND STATIC STRETCHING WITHIN GENERAL AND ACTIVITY SPECIFIC WARM-UP PROTOCOLS

    Directory of Open Access Journals (Sweden)

    Michael Samson

    2012-06-01

    Full Text Available The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1 general aerobic warm-up with static stretching, 2 general aerobic warm-up with dynamic stretching, 3 general and specific warm-up with static stretching and 4 general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested for movement time (kicking movement of leg over 0.5 m distance, countermovement jump height, sit and reach flexibility and 6 repetitions of 20 metre sprints. Results indicated that when a sport specific warm-up was included, there was an 0.94% improvement (p = 0.0013 in 20 meter sprint time with both the dynamic and static stretch groups. No such difference in sprint performance between dynamic and static stretch groups existed in the absence of the sport specific warm-up. The static stretch condition increased sit and reach range of motion (ROM by 2.8% more (p = 0.0083 than the dynamic condition. These results would support the use of static stretching within an activity specific warm-up to ensure maximal ROM along with an enhancement in sprint performance

  18. 600 Volt Stretched Lens Array for Solar Electric Propulsion, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — ENTECH, Auburn, NASA, and others have recently developed a new space photovoltaic array called the Stretched Lens Array (SLA), offering unprecedented performance...

  19. Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

    Science.gov (United States)

    Miyamoto, N; Hirata, K; Kanehisa, H

    2017-01-01

    The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Implementation of a controller for linear positioners applicable in optical fiber stretching

    International Nuclear Information System (INIS)

    Castrillo Piedra, Andres Rodolfo

    2014-01-01

    A low cost controller is implemented for linear positioners applicable in optic fiber stretching. The possibility of using a donated equipment is evaluated by the Escuela de Ingenieria Mecanica. The equipment is required by the non-linear photonic research laboratory (NLPR-LAB) for stretching of micro structured fiber. The process has required a slow and precise stretching, so the controllers must be precisely programmed to rotate the motors at different speeds. Donated equipment is evaluated to see if it is possible to use for fiber stretching [es

  1. ACUTE EFFECTS OF THREE DIFFERENT STRETCHING PROTOCOLS ON THE WINGATE TEST PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Bruno L. Franco

    2012-03-01

    Full Text Available The purpose of this study was to examine the acute effects of different stretching exercises on the performance of the traditional Wingate test (WT. Fifteen male participants performed five WT; one for familiarization (FT, and the remaining four after no stretching (NS, static stretching (SS, dynamic stretching (DS, and proprioceptive neuromuscular facilitation (PNF. Stretches were targeted for the hamstrings, quadriceps, and calf muscles. Peak power (PP, mean power (MP, and the time to reach PP (TP were calculated. The MP was significantly lower when comparing the DS (7.7 ± 0.9 W/kg to the PNF (7.3 ± 0.9 W/kg condition (p < 0.05. For PP, significant differences were observed between more comparisons, with PNF stretching providing the lowest result. A consistent increase of TP was observed after all stretching exercises when compared to NS. The results suggest the type of stretching, or no stretching, should be considered by those who seek higher performance and practice sports that use maximal anaerobic power.

  2. Effect of Ankle Positioning During Hamstring Stretches for Improving Straight Leg Hip Flexion Motion.

    Science.gov (United States)

    Laudner, Kevin G; Benjamin, Peter J; Selkow, Noelle M

    2016-03-01

    To compare the effects of stretching the hamstrings with the ankle in either a plantar-flexed (PF) or dorsiflexed (DF) position for improving straight leg hip flexion range of motion (ROM) over a 4-week period. Randomized, single-blinded, pretest, posttest design. Athletic training facility. Each limb of 34 asymptomatic individuals (15 males, 19 females) was randomly assigned to one of the 3 groups. Twenty-four limbs received hamstring stretches with the ankle in DF, 24 limbs received hamstring stretches with the ankle in PF, and 20 limbs received no stretch (control). Ankle position (PF, DF) during hamstring stretching. We measured pretest and posttest passive straight leg hip flexion ROM with the test ankle in a neutral position. For the intervention groups, the test limb was passively stretched with the ankle held in end range DF or PF for their respective group. Each stretch was held for 30 seconds for a total of 3 applications. Two treatment sessions were completed per week for a total of 4 weeks. The control limbs received no stretching during the 4-week period. We conducted 1-way analyses of covariance to determine significant changes in ROM between groups (P hamstrings in either PF or DF improve straight leg hip ROM compared with a control group. The results of this study should be considered by clinicians when determining the optimal stretching techniques aimed at increasing hamstring length.

  3. The acute effects of stretching with vibration on dynamic flexibility in young female gymnasts.

    Science.gov (United States)

    Johnson, Aaron W; Warcup, Caisa N; Seeley, Matthew K; Eggett, Dennis; Feland, Jeffery B

    2018-01-10

    While stretching with vibration has been shown to improve static flexibility; the effect of stretching with vibration on dynamic flexibility is not well known. The purpose of this study was to examine the effectiveness of stretching with vibration on acute dynamic flexibility and jump height in novice and advanced competitive female gymnasts during a split jump. Female gymnast (n=27, age: 11.5 ± 1.7 years, Junior Olympic levels 5-10) participated in this cross-over study. Dynamic flexibility during gymnastic split jumps were video recorded and analyzed with Dartfish software. All participants completed both randomized stretching protocols with either the vibration platform turned on (VIB) (frequency of 30 Hz and 2 mm amplitude) or off (NoVIB) separated by 48 h. Participants performed 4 sets of three stretches on the vibration platform. Each stretch was held for 30 s with 5 s rest for a total of 7 min of stretch. Split jump flexibility decreased significantly from pre to post measurement in both VIB (-5.8°±5.9°) (pstatic stretching with or without vibration immediately before performance does not alter jump height. Stretching with vibration immediately prior to gymnastics competition decreases split jump flexibility in lower level gymnasts more than upper level gymnasts.

  4. Acute decrease in the stiffness of resting muscle belly due to static stretching.

    Science.gov (United States)

    Taniguchi, K; Shinohara, M; Nozaki, S; Katayose, M

    2015-02-01

    The purpose of the study was to examine the acute effect of static stretching exercise on the resting stiffness of gastrocnemius muscle belly. Ten healthy young adults performed standing wall stretching in dorsiflexion for 1 min at a time and repeated five times. Before and after stretching, the shear modulus was measured in medial and lateral heads of the resting gastrocnemius muscle with ultrasound shear-wave elastography. After the stretching, dorsiflexion range of motion (ROM) of the ankle joint increased (P stretching, shear modulus decreased (P stretching across muscle heads. The decrease in shear modulus returned in 20 min after stretching. In the comparison group of 10 additional subjects, the standing intervention without stretching had no influence on these measures. There was a negative correlation between dorsiflexion ROM and shear modulus in either head before and after stretching. The results demonstrate the transient decreases in the stiffness of the resting gastrocnemius muscle belly and indicate that joint flexibility is greater in individuals with lower resting stiffness of the muscle belly. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Acute effects of passive stretching of the plantarflexor muscles on neuromuscular function: the influence of age.

    Science.gov (United States)

    Ryan, Eric D; Herda, Trent J; Costa, Pablo B; Herda, Ashley A; Cramer, Joel T

    2014-01-01

    The acute effects of stretching on peak force (Fpeak), percent voluntary activation (%VA), electromyographic (EMG) amplitude, maximum range of motion (MROM), peak passive torque, the passive resistance to stretch, and the percentage of ROM at EMG onset (%EMGonset) were examined in 18 young and 19 old men. Participants performed a MROM assessment and a maximal voluntary contraction of the plantarflexors before and immediately after 20 min of passive stretching. Fpeak (-11 %), %VA (-6 %), and MG EMG amplitude (-9 %) decreased after stretching in the young, but not the old (P > 0.05). Changes in Fpeak were related to reductions in all muscle activation variables (r = 0.56-0.75), but unrelated to changes in the passive resistance to stretch (P ≥ 0.24). Both groups experienced increases in MROM and peak passive torque and decreases in the passive resistance to stretch. However, the old men experienced greater changes in MROM (P stretching for both groups (P = 0.213), but occurred earlier in the old (P = 0.06). The stretching-induced impairments in strength and activation in the young but not the old men may suggest that the neural impairments following stretching are gamma-loop-mediated. In addition, the augmented changes in MROM and passive torque and the lack of change in %EMGonset for the old men may be a result of age-related changes in muscle-tendon behavior.

  6. Rat cutaneous RA afferents activated by two-dimensional skin stretch.

    Science.gov (United States)

    Grigg, Peter; Robichaud, Daniel R

    2004-07-01

    Skin develops biaxial stresses and strains when stretched. Rapidly adapting cutaneous mechanoreceptor neurons are known to be stretch sensitive, yet in the past, they have been studied using stretch stimuli applied along only a single direction. In this study, cutaneous rapidly adapting mechanoreceptors were studied in preparations of isolated skin in which the skin was stretched dynamically using biaxial stretch stimuli and in which loads and displacements were measured along two directions. Stretch stimuli followed a pseudo-Gaussian waveform and were applied along either one or two directions simultaneously. Associations between spikes and mechanical variables were determined using multiple logistic regression. When the skin was actuated along a single direction, holding the orthogonal axis fixed, spike responses were strongly associated with mechanical variables along the actuated direction. The variables were stress and its rate of change, the rate of change of strain, and the product of stress and its rate of change, which is proportional to strain energy density. When the skin was stretched along a single direction, spikes were very poorly associated with stress variables measured along the direction orthogonal to the stretch. Afferents showed weak directional selectivity: they were slightly more responsive to the variable stress along the circumferential direction of the hindlimb. When the skin was stretched biaxially (i.e., along both directions simultaneously) with identical pseudo-Gaussian noise stimuli, neuronal responses were associated with the same variables as above, but the associations were weaker.

  7. Design spectra development considering short time histories

    International Nuclear Information System (INIS)

    Weiner, E.O.

    1983-01-01

    The need for generation of seismic acceleration histories to prescribed response spectra arises several ways in structural dynamics. For example, one way of obtaining floor spectra is to generate a history from a foundation spectra and then solve for the floor motion from which a floor spectrum can be obtained. Two separate programs, MODQKE and MDOF, were written to provide a capability of obtaining equipment spectra from design spectra. MODQKE generates or modifies acceleration histories to conform with design spectra pertaining to, say, a foundation. MDOF is a simple linear modal superposition program that solves for equipment support histories using the design spectra conforming histories as input. Equipment spectra, then, are obtained from the support histories using MODQKE

  8. Identifying the structure of 4-chlorophenyl isocyanide adsorbed on Au(111) and Pt(111) surfaces by first-principles simulations of Raman spectra.

    Science.gov (United States)

    Hu, Wei; Duan, Sai; Zhang, Yujin; Ren, Hao; Jiang, Jun; Luo, Yi

    2017-12-13

    Surface Raman spectroscopy has become one of the most powerful analytical tools for interfacial structures. However, theoretical modeling for the Raman spectra of molecular adsorbate on metallic surfaces is a long-standing challenge because accurate descriptions of the electronic structure for both the metallic substrates and adsorbates are required. Here we present a quasi-analytical method for high-precision surface Raman spectra at the first principle level. Using this method, we correlate both geometrical and electronic structures of a single 4-chlorophenyl isocyanide (CPI) molecule adsorbed on a Au(111) or Pt(111) surface with its Raman spectra. The "finger-print" frequency shift of the CN stretching mode reveals the in situ configuration of CPI is vertical adsorption on the top site of the Au(111) surface, but a bent configuration when it adsorbs on the hollow site of the Pt(111) surface. Electronic structure calculations reveal that a π-back donation mechanism often causes a red shift to the Raman response of CN stretching mode. In contrast, σ donation as well as a wall effect introduces a blue shift to the CN stretching mode. A clear relationship for the dependence of Raman spectra on the surface electronic and geometrical information is built up, which largely benefits the understanding of chemical and physical changes during the adsorption. Our results highlight that high-precision theoretical simulations are essential for identifying in situ geometrical and electronic surface structures.

  9. Operator functions and localization of spectra

    CERN Document Server

    Gil’, Michael I

    2003-01-01

    "Operator Functions and Localization of Spectra" is the first book that presents a systematic exposition of bounds for the spectra of various linear nonself-adjoint operators in a Hilbert space, having discrete and continuous spectra. In particular bounds for the spectra of integral, differential and integro-differential operators, as well as finite and infinite matrices are established. The volume also presents a systematic exposition of estimates for norms of operator-valued functions and their applications.

  10. Wavelet spectra of JACEE events

    International Nuclear Information System (INIS)

    Suzuki, Naomichi; Biyajima, Minoru; Ohsawa, Akinori.

    1995-01-01

    Pseudo-rapidity distributions of two high multiplicity events Ca-C and Si-AgBr observed by the JACEE are analyzed by a wavelet transform. Wavelet spectra of those events are calculated and compared with the simulation calculations. The wavelet spectrum of the Ca-C event somewhat resembles that simulated with the uniform random numbers. That of Si-AgBr event, however, is not reproduced by simulation calculations with Poisson random numbers, uniform random numbers, or a p-model. (author)

  11. Rotational spectra and molecular structure

    CERN Document Server

    Wollrab, James E

    1967-01-01

    Physical Chemistry, A Series of Monographs: Rotational Spectra and Molecular Structure covers the energy levels and rotational transitions. This book is divided into nine chapters that evaluate the rigid asymmetric top molecules and the nuclear spin statistics for asymmetric tops. Some of the topics covered in the book are the asymmetric rotor functions; rotational transition intensities; classes of molecules; nuclear spin statistics for linear molecules and symmetric tops; and classical appearance of centrifugal and coriolis forces. Other chapters deal with the energy levels and effects of ce

  12. Automation of a single-DNA molecule stretching device

    DEFF Research Database (Denmark)

    Sørensen, Kristian Tølbøl; Lopacinska, Joanna M.; Tommerup, Niels

    2015-01-01

    We automate the manipulation of genomic-length DNA in a nanofluidic device based on real-time analysis of fluorescence images. In our protocol, individual molecules are picked from a microchannel and stretched with pN forces using pressure driven flows. The millimeter-long DNA fragments free...... flowing in micro- and nanofluidics emit low fluorescence and change shape, thus challenging the image analysis for machine vision. We demonstrate a set of image processing steps that increase the intrinsically low signal-to-noise ratio associated with single-molecule fluorescence microscopy. Furthermore......, we demonstrate how to estimate the length of molecules by continuous real-time image stitching and how to increase the effective resolution of a pressure controller by pulse width modulation. The sequence of image-processing steps addresses the challenges of genomic-length DNA visualization; however...

  13. Machine-Stitched E-textile Stretch Sensors

    Directory of Open Access Journals (Sweden)

    Guido Gioberto

    2016-07-01

    Full Text Available Truly wearable sensing poses challenges in many areas. To be successful, wearable sensors must preserve wearer comfort while providing accurate sensor data. Further, for widespread commercial production they must also be compatible with soft goods manufacturing. Here, we present a method of fabricating stretch sensors using common apparel sewing machinery. The response of sensors made using industrial coverstitch (two varieties and overlock machines are compared, and the sensor response of a bottom-thread coverstitch is characterized in depth. Three conductive thread structures are compared in the bottom-thread coverstitch sensor. Results show a consistent and repeatable response for 4- and 5-ply threads, while 2-ply thread displayed more noise and less repeatability. Finally, this sensor is applied in a spinal goniometry application in three garment structures, and sensor performance is compared to motion capture data. The fabrication approach is promising for wearable sensing applications due to its manufacturability and comfort.

  14. Mechanical response of human female breast skin under uniaxial stretching.

    Science.gov (United States)

    Kumaraswamy, N; Khatam, Hamed; Reece, Gregory P; Fingeret, Michelle C; Markey, Mia K; Ravi-Chandar, Krishnaswamy

    2017-10-01

    Skin is a complex material covering the entire surface of the human body. Studying the mechanical properties of skin to calibrate a constitutive model is of great importance to many applications such as plastic or cosmetic surgery and treatment of skin-based diseases like decubitus ulcers. The main objective of the present study was to identify and calibrate an appropriate material constitutive model for skin and establish certain universal properties that are independent of patient-specific variability. We performed uniaxial tests performed on breast skin specimens freshly harvested during mastectomy. Two different constitutive models - one phenomenological and another microstructurally inspired - were used to interpret the mechanical responses observed in the experiments. Remarkably, we found that the model parameters that characterize dependence on previous maximum stretch (or preconditioning) exhibited specimen-independent universal behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Stretching a semiflexible polymer with orientation-dependent interactions

    International Nuclear Information System (INIS)

    Zhen Yi; Vilgis, Thomas A

    2009-01-01

    The mean field variational approach is employed to study the effect of a nematic field and an external constant force field on the elasticity of a semiflexible polymer. In the stationary phase, we obtain the force–extension relationship and calculate the hairpin density of a stretched semiflexible polymer in nematic solvents. The force–extension behavior is found to be controlled by the parameters gl p and gf where g is the strength of the nematic field, l p is the bare persistence length and f is the external force. Several distinct regimes for the elastic response and the hairpin density emerge depending on the value of gl p and gf. Qualitative comparisons between our computation and other theories are presented

  16. Nitro Stretch Probing of a Single Molecular Layer to Monitor Shock Compression with Picosecond Time-Resolution

    Science.gov (United States)

    Berg, Christopher; Lagutchev, Alexei; Fu, Yuanxi; Dlott, Dana

    2011-06-01

    To obtain maximum possible temporal resolution, laser-driven shock compression of a molecular monolayer was studied using vibrational spectroscopy. The stretching transitions of nitro groups bound to aromatic rings was monitored using a nonlinear coherent infrared spectroscopy termed sum-frequency generation, which produced high-quality signals from this very thin layer. To overcome the shock opacity problem, a novel polymer overcoat method allowed us to make the observation window (witness plate) a few micrometers thick. The high signal-to-noise ratios (>100:1) obtained via this spectroscopy allowed us to study detailed behavior of the shocked molecules. To help interpret these vibrational spectra, additional spectra were obtained under conditions of static pressures up to 10 GPa and static temperatures up to 1000 C. Consequently, this experiment represents a significant step in resolving molecular dynamics during shock compression and unloading with both high spatial and temporal resolution. Supported by the Stewardship Sciences Academic Alliance Program from the Carnegie-DOE Alliance Center under grant number DOE CIW 4-3253-13 and the US Air Force Office of Scientific Research under award number FAA9550-09-1-0163.

  17. Cyclic mechanical stretch reduces myofibroblast differentiation of primary lung fibroblasts.

    Science.gov (United States)

    Blaauboer, Marjolein E; Smit, Theo H; Hanemaaijer, Roeland; Stoop, Reinout; Everts, Vincent

    2011-01-07

    In lung fibrosis tissue architecture and function is severely hampered by myofibroblasts due to excessive deposition of extracellular matrix and tissue contraction. Myofibroblasts differentiate from fibroblasts under the influence of transforming growth factor (TGF) β(1) but this process is also controlled mechanically by cytoskeletal tension. In healthy lungs, the cytoskeleton of fibroblasts is mechanically strained during breathing. In stiffer fibrotic lung tissue, this mechanical stimulus is reduced, which may influence fibroblast-to-myofibroblast differentiation. Therefore, we investigated the effect of cyclic mechanical stretch on fibroblast-to-myofibroblast differentiation. Primary normal human lung fibroblasts were grown on BioFlex culture plates and stimulated to undergo myofibroblast differentiation by 10 ng/ml TGFβ(1). Cells were either or not subjected to cyclic mechanical stretch (sinusoidal pattern, maximum elongation 10%, 0.2 Hz) for a period of 48 h on a Flexercell apparatus. mRNA expression was analyzed by real-time PCR. Cyclic mechanical loading reduced the mRNA expression of the myofibroblast marker α-smooth muscle actin and the extracellular matrix proteins type-I, type-III, and type-V collagen, and tenascin C. These outcomes indicate that fibroblast-to-myofibroblast differentiation is reduced. Cyclic mechanical loading did not change the expression of the fibronectin ED-A splice variant, but did decrease the paracrine expression of TGFβ(1), thereby suggesting a possible regulation mechanism for the observed effects. The data suggest that cyclic loading experienced by healthy lung cells during breathing may prevent fibroblasts from differentiating towards myofibroblasts. Copyright © 2010 Elsevier Inc. All rights reserved.

  18. Pion scattering to 8- stretched states in 60Ni

    International Nuclear Information System (INIS)

    Clausen, B.L.

    1988-03-01

    Using the Energetic Pion Channel and Spectrometer at the Los Alamos Meson Physics Facility, differential cross sections for pion scattering were measured for ten previously known J/sup π/ = 8/sup /minus// stretched states in 60 Ni. A possible new pure isoscalar stretched state was also found. The data were taken near the /DELTA//sub 3,3/-resonance using 162 MeV incident pions and scattering angles of 65/degree/, 80/degree/, and 90/degree/ for π + and 65/degree/ and 80/degree/ for π/sup /minus//. The analysis of the 60 Ni data found that the use of Woods-Saxon wave functions in the theoretical calculations gave much better agreement with data than the use of the usual harmonic oscillator wave functions. The WS theory gave better predictions of: the angle at which the π/sup /minus// and π + angular distributions are maximum, the ratios of π/sup /minus// to π + cross sections for pure isovector states (which were much larger than unity), and the absolute size of the cross sections for all states (so that the normalization factor necessary to arrive at agreement of theory with data was closer to unity). The theoretical calculations used the distorted wave impulse approximation, including new methods for unbound states. The sensitivities of the calculations to input parameters were investigated. This analysis using WS wave functions was extended to five other nuclei ( 12 C, 14 C, 16 O, 28 Si, and 54 Fe) on which both pion scattering and electron scattering have been done. A significant improvement in arriving at a normalization factor close to unity was found when WS wave functions were consistently used for analyzing both pion and electron inelastic scattering data. 101 refs., 26 figs., 13 tabs

  19. A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

    KAUST Repository

    Chang, Y.-H.

    2018-02-26

    Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non-planar transverse stretching process was employed in this study to produce micro-porous structure. The morphology, membrane thickness, mean pore size, and porosity of the PTFE membrane were investigated. The results show that the non-planar transverse stretched membranes exhibit more uniform average pore diameter with thinner membrane thickness. Morphological changes induced by planar and non-planar transverse stretching for pore characteristics were investigated. The stretching conditions, stretching temperature and rate, affect the stretched membrane. Increasing temperature facilitated the uniformity of pore size and uniformity of membrane thickness. Moreover, increase in stretching rate resulted in finer pore size and thinner membrane.

  20. Effects of dynamic and static stretching within general and activity specific warm-up protocols.

    Science.gov (United States)

    Samson, Michael; Button, Duane C; Chaouachi, Anis; Behm, David G

    2012-01-01

    The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1) general aerobic warm-up with static stretching, 2) general aerobic warm-up with dynamic stretching, 3) general and specific warm-up with static stretching and 4) general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested for movement time (kicking movement of leg over 0.5 m distance), countermovement jump height, sit and reach flexibility and 6 repetitions of 20 metre sprints. Results indicated that when a sport specific warm-up was included, there was an 0.94% improvement (p = 0.0013) in 20 meter sprint time with both the dynamic and static stretch groups. No such difference in sprint performance between dynamic and static stretch groups existed in the absence of the sport specific warm-up. The static stretch condition increased sit and reach range of motion (ROM) by 2.8% more (p = 0.0083) than the dynamic condition. These results would support the use of static stretching within an activity specific warm-up to ensure maximal ROM along with an enhancement in sprint performance. Key pointsActivity specific warm-up may improve sprint performance.Static stretching was more effective than dynamic stretching for increasing static range of motion.There was no effect of the warm-up protocols on countermovement jump height or movement time.

  1. Crustal Stretching Style and Lower Crust Flow of the South China Sea Northern Margin

    Science.gov (United States)

    Bai, Y.; Dong, D.; Runlin, D.

    2017-12-01

    There is a controversy about crustal stretching style of the South China Sea (SCS) northern margin mainly due to considerable uncertainty of stretching factor estimation, for example, as much as 40% of upper crust extension (Walsh et al., 1991) would be lost by seismic profiles due to poor resolution. To discover and understand crustal stretching style and lower crustal flow on the whole, we map the Moho and Conrad geometries based on gravity inversion constrained by deep seismic profiles, then according to the assumption of upper and lower crust initial thickness, upper and lower crust stretching factors are estimated. According to the comparison between upper and lower crust stretching factors, the SCS northern margin could be segmented into three parts, (1) sediment basins where upper crust is stretched more than lower crust, (2) COT regions where lower crust is stretched more than upper crust, (3) other regions where the two layers have similar stretching factors. Stretching factor map shows that lower crust flow happened in both of COT and sediment basin regions where upper crust decouples with lower crust due to high temperature. Pressure contrast by sediment loading in basins and erosion in sediment-source regions will lead to lower crust flow away from sediment sink to source. Decoupled and fractured upper crust is stretched further by sediment loading and the following compensation would result in relatively thick lower crust than upper crust. In COT regions with thin sediment coverage, low-viscosity lower crust is easier to thin in extensional environment, also the lower crust tends to flow away induced by magma upwelling. Therefore, continental crust on the margin is not stretching in a constant way but varies with the tectonic setting changes. This work is supported by National Natural Science Foundation of China (Grant No. 41506055, 41476042) and Fundamental Research Funds for the Central Universities China (No.17CX02003A).

  2. Acute effects of 15min static or contract-relax stretching modalities on plantar flexors neuromuscular properties.

    Science.gov (United States)

    Babault, Nicolas; Kouassi, Blah Y L; Desbrosses, Kevin

    2010-03-01

    The present study aimed to investigate the immediate effects of 15 min static or sub-maximal contract-relax stretching modalities on the neuromuscular properties of plantar flexor muscles. Ten male volunteers were tested before and immediately after 15 min static or contract-relax stretching programs of plantar flexor muscles (20 stretches). Static stretching consisted in 30s stretches to the point of discomfort. For the contract-relax stretching modality, subjects performed 6s sub-maximal isometric plantar flexion before 24s static stretches. Measurements included maximal voluntary isometric torque (MVT) and the corresponding electromyographic activity of soleus (SOL) and medial gastrocnemius (MG) muscles (RMS values), as well as maximal peak torque (Pt) elicited at rest by single supramaximal electrical stimulation of the tibial nerve. After 15 min stretching, significant MVT and SOL RMS decreases were obtained (-6.9+/-11.6% and -6.5+/-15.4%, respectively). No difference was obtained between stretching modalities. Pt remained unchanged after stretching. MG RMS changes were significantly different between stretching modalities (-9.4+/-18.3% and +3.5+/-11.6% after static and contract-relax stretching modalities, respectively). These findings indicated that performing 15 min static or contract-relax stretching had detrimental effects on the torque production capacity of plantar flexor muscles and should be precluded before competition. Mechanisms explaining this alteration seemed to be stretch modality dependent. Copyright 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  3. Phonon Raman spectra of colloidal CdTe nanocrystals: effect of size, non-stoichiometry and ligand exchange

    Directory of Open Access Journals (Sweden)

    Lokteva Irina

    2011-01-01

    Full Text Available Abstract Resonant Raman study reveals the noticeable effect of the ligand exchange on the nanocrystal (NC surface onto the phonon spectra of colloidal CdTe NC of different size and composition. The oleic acid ligand exchange for pyridine ones was found to change noticeably the position and width of the longitudinal optical (LO phonon mode, as well as its intensity ratio to overtones. The broad shoulder above the LO peak frequency was enhanced and sharpened after pyridine treatment, as well as with decreasing NC size. The low-frequency mode around 100 cm-1 which is commonly related with the disorder-activated acoustical phonons appears in smaller NCs but is not enhanced after pyridine treatment. Surprisingly, the feature at low-frequency shoulder of the LO peak, commonly assigned to the surface optical phonon mode, was not sensitive to ligand exchange and concomitant close packing of the NCs. An increased structural disorder on the NC surface, strain and modified electron-phonon coupling is discussed as the possible reason of the observed changes in the phonon spectrum of ligand-exchanged CdTe NCs. PACS: 63.20.-e, 78.30.-j, 78.67.-n, 78.67.Bf

  4. Spectroscopic properties of neuroleptics: IR and Raman spectra of Risperidone (Risperdal) and of its mono- and di-protonated forms

    Science.gov (United States)

    Alparone, Andrea

    2011-10-01

    Structures and IR and Raman spectra of Risperidone in its neutral, mono- and di-protonated forms were calculated in gas phase by DFT-B3LYP/6-31G* level. Mono-protonation occurs at the nitrogen atom of the piperidine ring, while nitrogen atom of the pyrimidine ring is the preferred site for the second protonation. The lowest-energy structure of the mono-protonated Risperidone is characterized by formation of a strong seven-membered O(pyrimidine ring)⋯ +H-N(piperidine ring) intramolecular hydrogen-bonded cycle. In the high-energy spectral region (3500-2500 cm -1), the bands of the N-H + stretches and the changes in wavenumbers and IR intensities of the C-H stretches near to the piperidine nitrogen atom (Bohlmann effect) are potentially useful to discriminate conformations and protonation states. Di-protonated structures can be identified by the presence of an isolated absorption peak located in the low-energy IR region (660-690 cm -1), attributed to the out-of-plane N-H +(pyrimidine ring) bending deformation. The most intense Raman band of neutral Risperidone placed at ca. 1500 cm -1, assigned to C dbnd C(pyrimidine ring) stretch + C dbnd N(pyrimidine ring) stretch, can be a useful vibrational marker to distinguish the neutral from the protonated forms.

  5. Scikit-spectra: Explorative Spectroscopy in Python

    Directory of Open Access Journals (Sweden)

    Adam Hughes

    2015-06-01

    Full Text Available Scikit-spectra is an intuitive framework for explorative spectroscopy in Python. Scikit-spectra leverages the Pandas library for powerful data processing to provide datastructures and an API designed for spectroscopy. Utilizing the new IPython Notebook widget system, scikit-spectra is headed towards a GUI when you want it, API when you need it approach to spectral analysis. As an application, analysis is presented of the surface-plasmon resonance shift in a solution of gold nanoparticles induced by proteins binding to the gold’s surface. Please refer to the scikit-spectra website for full documentation and support: http://hugadams.github.io/scikit-spectra/

  6. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

    Directory of Open Access Journals (Sweden)

    Abdullah Serefoglu, Ufuk Sekir, Hakan Gür, Bedrettin Akova

    2017-03-01

    Full Text Available The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a non-stretching (control, (b static stretching of the quadriceps muscles, (c static stretching of the hamstring muscles, (d dynamic stretching of the quadriceps muscles, and (e dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05 differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05 following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG

  7. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles.

    Science.gov (United States)

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-03-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) non-stretching (control), (b) static stretching of the quadriceps muscles, (c) static stretching of the hamstring muscles, (d) dynamic stretching of the quadriceps muscles, and (e) dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG) activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05) differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05) following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG activities

  8. Near-infrared laser-induced structural changes of glycine·water complexes in an Ar matrix.

    Science.gov (United States)

    Kócs, Lenke; Najbauer, Eszter E; Bazsó, Gábor; Magyarfalvi, Gábor; Tarczay, György

    2015-03-19

    The structures of glycine·H2O complexes have been reinvestigated in low-temperature inert matrices. To go beyond the former matrix-isolation IR studies, NIR laser irradiation was used to change the relative abundances of the different complexes in the matrix. It is shown that the irradiation of the first overtone of the OH stretching mode of glycine as well as of the first overtone of the OH stretching mode of the water molecule in the complex can induce structural changes. Comparison of the experimental IR spectra with the IR spectra computed for different structures resulted in more reliable assignments of spectral patterns and identification of more structures than in former studies.

  9. Infrared spectra of phosphate sorbed on iron hydroxide gel and the sorption products

    International Nuclear Information System (INIS)

    Nanzyo, M.

    1986-01-01

    Infrared absorption spectra of phosphate sorbed on iron hydroxide gel were obtained by applying the differential diffuse reflectance method. Absorption bands due to P-O stretching vibration were observed at 1,110 and 1,010 cm -1 at pH 12.3. With decreasing pH, these absorption bands gradually shifted to 1,100 and 1,020 cm -1 at pH 4.9. At pH 2.3, they became a broad single absorption band at 1,060 cm -1 . At pH 11 or above, the difference in the Na + adsorption between phosphated iron hydroxide gel and iron hydroxide gel was almost equal to the amount of phosphate sorption. This finding shows that phosphate was retained on the iron hydroxide gel surface as a bidentate ligand at a high pH. It was concluded that at a high pH phosphate was sorbed on iron hydroxide gel as a binuclear surface complex similar to that on goethite; the change in spectra for P-O stretching vibration with decreasing pH value was mainly caused by an increase in the fraction of amorphous iron phosphate; at pH 2.3, the phosphate sorption product consisted of amorphous iron phosphate. (author)

  10. Different spectra with the same neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Mercado, G. A., E-mail: fermineutron@yahoo.co [Universidad Autonoma de Zacatecas, Unidad Academica de Matematicas, Jardin Juarez No. 147, 98000 Zacatecas (Mexico)

    2010-02-15

    Using as source term the spectrum of a {sup 239}Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a {sup 239}Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  11. Different spectra with the same neutron source

    International Nuclear Information System (INIS)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A.; Mercado, G. A.

    2010-01-01

    Using as source term the spectrum of a 239 Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239 Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  12. The effects of static stretch duration on the flexibility of hamstring ...

    African Journals Online (AJOL)

    The effects of static stretch duration on the flexibility of hamstring muscles. NA Odunaiya, TK Hamzat, OF Ajayi. Abstract. The effects of duration of a static stretching protocol (Intervention) on hamstrings tightness were evaluated. Sixty purposively sampled subjects with unilateral hamstring tightness that had no history of low ...

  13. The Effect of Lithotomy Position on Nerve Stretch: A Cadaveric Study.

    Science.gov (United States)

    Deveneau, Nicolette E; Forbis, Courtney; Lipetskaia, Lioudmilla; Kinman, Casey L; Agrawal, Anubhav; Herring, Nicole R; Francis, Sean L

    The objective of our study was to design a method to measure nerve stretch in cadaveric subjects and then use the method to assess femoral nerve stretch in the lithotomy position with varying degrees of flexion and extension. A university-based, cadaveric observational study of femoral nerve stretch was conducted. In 6 cadaveric subjects, femoral nerve near the inguinal ligament was dissected in each cadaveric subject. The nerve was marked, and digital images of the nerve were obtained in the supine position and lithotomy position in both flexion and extension. Distances were calculated using the ratio of pixels to millimeter specific for each image. The average distance for each set of images was then used to calculate the percent change from supine for each position. We were able to assess nerve stretch using photo-editing software. For extended position, all nerves showed some degree of stretch with the mean percent change in nerve length being 10.35%. For all other positions, most showed a decrease of nerve length. There was not a significant relation between degree of extension and stretch (Pearson r, P < 0.05). Hip extension between 10 and 20 degrees consistently stretches the femoral nerve greater than 5%. The potential for femoral nerve stretch and avoiding hip extension should be considered when positioning a patient in lithotomy for surgical procedures.

  14. From Static Stretching to Dynamic Exercises: Changing the Warm-Up Paradigm

    Science.gov (United States)

    Young, Shawna

    2010-01-01

    In the United States, pre-exercise static stretching seems to have become common practice and routine. However, research suggests that it is time for a paradigm shift--that pre-exercise static stretching be replaced with dynamic warm-up exercises. Research indicates that a dynamic warm-up elevates body temperature, decreases muscle and joint…

  15. Dual solutions of Casson fluid flow over a stretching or shrinking sheet

    Indian Academy of Sciences (India)

    ing parameter is negative. The effect of the Casson parameter on the skin friction, heat transfer and mass transfer rates is discussed. Keywords. Casson fluid; stretching/shrinking sheet; Soret effect; Dufour effect. 1. Introduction. Boundary layer flow and heat transfer over a stretching sheet is significant due to its many appli-.

  16. A Critical View of Static Stretching and Its Relevance in Physical Education

    Science.gov (United States)

    Parrott, James Allen; Zhu, Xihe

    2013-01-01

    Stretching before activity has been a customary part of most physical education classes (PE), with static stretching typically the preferred method due to its ease of implementation. Historical and implicit support for its continued use is due in part to the sit-and-reach test and flexibility as one of the components of health-related fitness.…

  17. Effect of proprioceptive neuromuscular facilitation stretching on the plantar flexor muscle-tendon tissue properties.

    Science.gov (United States)

    Mahieu, N N; Cools, A; De Wilde, B; Boon, M; Witvrouw, E

    2009-08-01

    Proprioceptive neuromuscular facilitation (PNF) stretching programs have been shown to be the most effective stretching technique to increase the range of motion (ROM). The objective of this study was to examine the mechanism of effect of PNF stretching on changes in the ROM. Sixty-two healthy subjects were randomized into two groups: a PNF stretching group and a control group. The PNF group performed a 6-week stretching program for the calf muscles. Before and after this period, all subjects were evaluated for dorsiflexion ROM, passive resistive torque (PRT) of the plantar flexors and stiffness of the Achilles tendon. The results of the study revealed that the dorsiflexion ROM was significantly increased in the PNF group (DeltaROMext: 5.97+/-0.671 degrees ; DeltaROMflex: 5.697+/-0.788 degrees ). The PRT of the plantar flexors and the stiffness of the Achilles tendon did not change significantly after 6 weeks of PNF stretching. These findings provide evidence that PNF stretching results in an increased ankle dorsiflexion. However, this increase in ROM could not be explained by a decrease of the PRT or by a change in stiffness of the Achilles tendon, and therefore can be explained by an increase in stretch tolerance.

  18. The Acute Effects of Upper Extremity Stretching on Throwing Velocity in Baseball Throwers

    Directory of Open Access Journals (Sweden)

    Michael Williams

    2013-01-01

    Full Text Available Purpose. To examine the effects of static and proprioceptive neuromuscular facilitation (PNF stretching of the shoulder internal rotators on throwing velocity. Subjects. 27 male throwers (mean age = 25.1 years old, SD = 2.4 with adequate knowledge of demonstrable throwing mechanics. Study Design. Randomized crossover trial with repeated measures. Methods. Subjects warmed up, threw 10 pitches at their maximum velocity, were randomly assigned to 1 of 3 stretching protocols (static, PNF, or no stretch, and then repeated their 10 pitches. Velocities were recorded after each pitch and average and peak velocities were recorded after each session. Results. Data were analyzed using a repeated measures ANOVA. No significant interaction between stretching and throwing velocity was observed. Main effects for time were not statistically significant. Main effects for the stretching groups were statistically significant. Discussion. Results suggest that stretching of the shoulder internal rotators did not significantly affect throwing velocity immediately after stretching. This may be due to the complexity of the throwing task. Conclusions. Stretching may be included in a thrower's warm-up without any effects on throwing velocity. Further research should be performed using a population with more throwing experience and skill.

  19. 49 CFR 180.413 - Repair, modification, stretching, rebarrelling, or mounting of specification cargo tanks.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Repair, modification, stretching, rebarrelling, or... Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS... of Cargo Tanks § 180.413 Repair, modification, stretching, rebarrelling, or mounting of specification...

  20. STRETCHING EXERCISES - EFFECT ON PASSIVE EXTENSIBILITY AND STIFFNESS IN SHORT HAMSTRINGS OF HEALTHY-SUBJECTS

    NARCIS (Netherlands)

    HALBERTSMA, JPK; GOEKEN, LNH

    Passive muscle stretch tests are common practice in physical therapy and rehabilitation medicine. However, the effects of stretching exercises are not well known. With an instrumental straight-leg-raising set-up the extensibility, stiffness, and electromyographic activity of the hamstring muscles

  1. Acute effect of different stretching methods on flexibility and jumping performance in competitive artistic gymnasts.

    Science.gov (United States)

    Dallas, G; Smirniotou, A; Tsiganos, G; Tsopani, D; Di Cagno, A; Tsolakis, Ch

    2014-12-01

    The purpose of this study was to investigate the acute effects of 3 different warm up methods of stretching (static, proprioceptive neuromuscular facilitation, and stretching exercises on a Vibration platform) on flexibility and legs power-jumping performance in competitive artistic gymnasts. Eighteen competitive artistic gymnasts were recruited to participate in this study. Subjects were exposed to each of 3 experimental stretching conditions: static stretching (SS), proprioceptive neuromuscular facilitation stretching (PNF), and stretching exercises on a Vibration platform (S+V). Flexibility assessed with sit and reach test (S & R) and jumping performance with squat jump (SJ) and counter movement jump (CMJ) and were measured before, immediately after and 15 min after the interventions. Significant differences were observed for flexibility after all stretching conditions for S+V (+1.1%), SS (+5.7%) and PNF (+6.8%) (P=0.000), which remained higher 15 min after interventions (S+V (1.1%), SS (5.3%) and PNF (5.5%), respectively (P=0.000). PNF stretching increased flexibility in competitive gymnasts, while S+V maintained jumping performance when both methods were used as part of a warm-up procedure.

  2. Improving multigrid for 3-D electro-magnetic diffusion on stretched grids

    NARCIS (Netherlands)

    Jönsthövel, T.B.; Oosterlee, C.W.; Mulder, W.A.

    2006-01-01

    We evaluated multigrid techniques for 3D diffusive electromagnetism. The Maxwell equations and Ohm's law were discretised on stretched grids, with stretching in all coordinate directions. We compared standard multigrid to alternative multigrid approaches with linewise smoothing and semi-coarsening,

  3. Comparison of 2 Dosages of Stretching Treatment in Infants with Congenital Muscular Torticollis: A Randomized Trial.

    Science.gov (United States)

    He, Lu; Yan, Xiaohua; Li, Jinling; Guan, Buyun; Ma, Liying; Chen, Ying; Mai, Jianning; Xu, Kaishou

    2017-05-01

    To compare the short-term efficacy of 2 dosages of stretching treatment on the clinical outcomes in infants with congenital muscular torticollis. This was a prospective randomized controlled study. Fifty infants with congenital muscular torticollis who were randomly assigned to 100-times stretching group and 50-times stretching group received stretching treatment for the affected sternocleidomastoid muscle. The outcomes including the head tilt, the cervical passive range of motion, and the muscle function of cervical lateral flexors determined by the muscle function scale were assessed at baseline and at 4 and 8 weeks after treatment. The sternocleidomastoid muscle growth analyzed by the thickness ratio of sternocleidomastoid muscles was measured using ultrasonography at baseline and 8 weeks after treatment. Except the ratio of muscle function scale scores, the postintervention outcomes were all significantly improved in both groups compared with baseline (P stretching group showed greater improvement compared with 50-times stretching group in head tilt and cervical passive range of motion at 4 and 8 weeks after treatment (P Stretching treatment of 2 dosages may effectively improve head tilt, cervical passive range of motion, and sternocleidomastoid muscle growth in infants with congenital muscular torticollis. The stretching treatment of 100 times per day is likely to associate with greater improvement in head tilt and cervical passive range of motion.

  4. On prediction of OH stretching frequencies in intramolecularly hydrogen bonded systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Spanget-Larsen, Jens

    2012-01-01

    OH stretching frequencies are investigated for a series of non-tautomerizing systems with intramolecular hydrogen bonds. Effective OH stretching wavenumbers are predicted by the application of empirical correlation procedures based on the results of B3LYP/6-31G(d) theoretical calculations in the ...

  5. The acute effect of static and dynamic stretching during warm-ups on anaerobic performance in trained women

    OpenAIRE

    rouhollah haghshenas; Iman taleb-beydokhti

    2014-01-01

    The purpose of this study was to investigate effects of static stretching, dynamic stretching and no stretching methods on power and speed in volleyball players. Therefore, Twenty-four volleyball players (height: 173.29 ± 7.81 m; mass: 62.12 ± 8.73 kg; age: 22.66 ± 4.02 years; experience: 3.27 ± 6.37) were tested for speed performance using the 20 meter sprint test and also for power using vertical jump test after static stretching, dynamic stretching and no stretching. The results analyzed u...

  6. Effect of static and dynamic stretching on the diurnal variations of jump performance in soccer players.

    Directory of Open Access Journals (Sweden)

    Hamdi Chtourou

    Full Text Available PURPOSE: The present study addressed the lack of data on the effect of different types of stretching on diurnal variations in vertical jump height - i.e., squat-jump (SJ and countermovement-jump (CMJ. We hypothesized that dynamic stretching could affect the diurnal variations of jump height by producing a greater increase in short-term maximal performance in the morning than the evening through increasing core temperature at this time-of-day. METHODS: Twenty male soccer players (age, 18.6±1.3 yrs; height, 174.6±3.8 cm; body-mass, 71.1±8.6 kg; mean ± SD completed the SJ and CMJ tests either after static stretching, dynamic stretching or no-stretching protocols at two times of day, 07:00 h and 17:00 h, with a minimum of 48 hours between testing sessions. One minute after warming-up for 5 minutes by light jogging and performing one of the three stretching protocols (i.e., static stretching, dynamic stretching or no-stretching for 8 minutes, each subject completed the SJ and CMJ tests. Jumping heights were recorded and analyzed using a two-way analysis of variance with repeated measures (3 [stretching]×2 [time-of-day]. RESULTS: The SJ and CMJ heights were significantly higher at 17:00 than 07:00 h (p<0.01 after the no-stretching protocol. These daily variations disappeared (i.e., the diurnal gain decreased from 4.2±2.81% (p<0.01 to 1.81±4.39% (not-significant for SJ and from 3.99±3.43% (p<0.01 to 1.51±3.83% (not-significant for CMJ after dynamic stretching due to greater increases in SJ and CMJ heights in the morning than the evening (8.4±6.36% vs. 4.4±2.64%, p<0.05 for SJ and 10.61±5.49% vs. 6.03±3.14%, p<0.05 for CMJ. However, no significant effect of static stretching on the diurnal variations of SJ and CMJ heights was observed. CONCLUSION: Dynamic stretching affects the typical diurnal variations of SJ and CMJ and helps to counteract the lower morning values in vertical jump height.

  7. Graviton spectra in string cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Galluccio, Massimo [Osservatorio Astronomico di Roma (Roma-IT); Litterio, Marco [Istituto Astronomico dell' Universita (Roma-IT); Occhionero, Franco [Osservatorio Astronomico di Roma (Roma-IT)

    1996-08-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an ω³ increase and initiates an ω⁻⁷ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre-Big Bang) and the expanding inflationary era (or post-Big Bang). We evaluate both analytically and numerically the frequency and the intensity of the peak and we show that they may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak is at variance with ordinarily monotonic (either increasing or decreasing) graviton spectra of canonical cosmologies; its detection would therefore offer strong support to string cosmology.

  8. Fatigue Crack Growth Characteristics of Cold Stretched STS 304 Welded Joint

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Won; Na, Seong Hyeon; Yoon, Dong Hyun; Kim, Jae Hoon [Chungnam Nat’l Univ., Daejeon (Korea, Republic of); Kim, Young Kyun; Kim, Ki Dong [Korea Gas Coporation R& D Division, Daejeon (Korea, Republic of)

    2017-09-15

    STS 304 steel is used as pressure vessel material, and although it exhibits excellent mechanical characteristics at a low temperature, it is heavier than other materials. To address this issue, a method using cold-stretching techniques for STS 304 can be applied. In this study, a cold-stretching part and welded joint specimen were directly obtained from a cold-stretching pressure vessel manufactured according to ASME code. Fatigue crack propagation tests were carried out at room temperature and -170℃ using the compliance method for stress ratios of 0.1 and 0.5. The results indicate that crack growth rate of the welded joint is higher than that of the cold-stretching part within the same stress intensity factor range. The outcome of this work is expected to serve as a basis for the development of a cold-stretched STS 304 pressure vessel.

  9. Comparison between static stretching and the Pilates method on the flexibility of older women.

    Science.gov (United States)

    Oliveira, Laís Campos de; Oliveira, Raphael Gonçalves de; Pires-Oliveira, Deise Aparecida de Almeida

    2016-10-01

    Flexibility decreases with advancing age and some forms of exercise, such as static stretching and Pilates, can contribute to the improvement of this physical ability. To compare the effects of static stretching and Pilates on the flexibility of healthy older women, over the age of 60 years. Thirty-two volunteers were randomized into two groups (Static stretching or Pilates) to perform exercises for 60 min, twice a week, for three months. Evaluations to analyze the movements of the trunk (flexion and extension), hip flexion and plantar and dorsiflexion of the ankle were performed before and after the intervention, using a fleximeter. The static stretching exercises improved the trunk flexion and hip flexion movements, while the Pilates improved all evaluated movements. However, over time, the groups presented differences only for the trunk extension movement. For some body segments, Pilates may be more effective for improving flexibility in older women compared to static stretching. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Range of motion, neuromechanical and architectural daptations to plantar flexor stretch training in humans

    DEFF Research Database (Denmark)

    Blazevich, Anthony John; Cannavan, Dale; Waugh, Charlie M

    2014-01-01

    flexor stretches after 3 wk of twice-daily stretch training (4×30-s). No changes were observed in a non-exercising control group (N=9), however stretch training elicited a 19.9% increase in dorsiflexion range of motion (ROM) and 28% increase in passive joint moment at end ROM (N=12). Only a trend toward......The neuromuscular adaptations in response to muscle stretch training have not been clearly described. In the present study, changes in muscle (at fascicular and whole muscle levels) and tendon mechanics, muscle activity and spinal motoneuron excitability were examined during standardized plantar...... a decrease in passive plantar flexor moment during stretch (-9.9%, p=0.15) was observed and no changes in EMG amplitudes during or at end ROM were detected. Decreases in Hmax:Mmax (tibial nerve stimulation) were observed at plantar flexed (gastrocnemius medialis and soleus) and neutral (soleus only) joint...

  11. Direct relation of acute effects of static stretching on isokinetic torque production with initial flexibility level.

    Science.gov (United States)

    Babault, Nicolas; Bazine, Wacef; Deley, Gaëlle; Paizis, Christos; Lattier, Grégory

    2015-01-01

    To examine the acute effect of a single static-stretching session of hamstring muscles on torque production in relation with individual flexibility. Maximal voluntary concentric torque of hamstring muscles was measured before and after a static-stretching session (6 × 30 s). Torque changes were correlated with the flexibility level determined at the onset of the experimental procedure. The hamstring-stretching intervention significantly reduced maximal concentric torque in participants with low and high hamstring flexibility. Hamstring flexibility and torque decrease, determined immediately after the stretching procedure, were negatively correlated. Torque decrease measured after the static-stretching session is dependent on participant flexibility. Participants with low flexibility are much more likely to demonstrate large torque decreases poststretching.

  12. Static vs. Dynamic Acute Stretching Effect on Quadriceps Muscle Activity during Soccer Instep Kicking

    Science.gov (United States)

    Amiri-Khorasani, Mohammadtaghi; Kellis, Eleftherios

    2013-01-01

    The purpose of this study was to compare the effects of static and dynamic stretching on quadriceps muscle activation during maximal soccer instep kicking. The kicking motion of twelve male college soccer players (body height: 174.66 ± 5.01 cm; body mass: 72.83 ± 4.83 kg; age: 18.83 ± 0.75 years) was captured using six synchronized high-speed infra-red cameras whilst electromyography (EMG) signals from vastus medialis (VM), lateralis (VL) and rectus femoris (RF) were recorded before and after static or dynamic stretching. Analysis of variance designs showed a higher increase in knee extension angular velocity (9.65% vs. −1.45%, p stretching exercises. Based on these results, it could be suggested that dynamic stretching is probably more effective in increasing quadriceps muscle activity and knee extension angular velocity during the final swing phase of a maximal soccer instep kick than static stretching. PMID:24511339

  13. A study of viscoelasticity index for evaluating muscle hypotonicity during static stretching.

    Science.gov (United States)

    Okamura, Naomi; Tsukune, Mariko; Kobayashi, Yo; Fujie, Masakatsu G

    2014-01-01

    Static stretching is widely used as a preventative treatment for musculoskeletal disabilities by providing muscle hypotonicity, which results from changes in muscle tissue structure. However, the quantitative evaluation of hypotonicity during stretching has had limited success owing to the confounding factor of mechanical stress relaxation. To resolve this problem, we propose a new evaluation method for hypotonicity based on a viscoelastic muscle model using fractional calculus, which is known to be effective for biomaterials. We made continuous measurements of rectus skin indentation during static stretching as an indicator of reaction force in the rectus femoris muscle. The viscoelastic ratio and modulus were computed from the indentation trace. Both viscoelastic parameters decreased significantly between the early and final phases of stretching. The results suggest that our method is useful for quantitative evaluation of muscle hypotonicity during stretching.

  14. Effect of Twisting and Stretching on Magneto Resistance and Spin Filtration in CNTs

    Directory of Open Access Journals (Sweden)

    Anil Kumar Singh

    2017-08-01

    Full Text Available Spin-dependent quantum transport properties in twisted carbon nanotube and stretched carbon nanotube are calculated using density functional theory (DFT and non-equilibrium green’s function (NEGF formulation. Twisting and stretching have no effect on spin transport in CNTs at low bias voltages. However, at high bias voltages the effects are significant. Stretching restricts any spin-up current in antiparallel configuration (APC, which results in higher magneto resistance (MR. Twisting allows spin-up current almost equivalent to the pristine CNT case, resulting in lower MR. High spin filtration is observed in PC and APC for pristine, stretched and twisted structures at all applied voltages. In APC, at low voltages spin filtration in stretched CNT is higher than in pristine and twisted ones, with pristine giving a higher spin filtration than twisted CNT.

  15. CH Stretching Region: Computational Modeling of Vibrational Optical Activity

    Czech Academy of Sciences Publication Activity Database

    Hudecová, Jana; Profant, V.; Novotná, P.; Baumruk, V.; Urbanová, M.; Bouř, Petr

    2013-01-01

    Roč. 9, č. 7 (2013), s. 3096-3108 ISSN 1549-9618 R&D Projects: GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Grant - others:AV ČR(CZ) M200550902 Institutional support: RVO:61388963 Keywords : density-functional theory * circular-dichroism spectra * N-methyl acetamide * alpha-pinene * Raman Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.310, year: 2013

  16. Sunlight-Initiated Photochemistry: Excited Vibrational States of Atmospheric Chromophores

    Directory of Open Access Journals (Sweden)

    Veronica Vaida

    2008-01-01

    Full Text Available Atmospheric chemical reactions are often initiated by ultraviolet (UV solar radiation since absorption in that wavelength range coincides to typical chemical bond energies. In this review, we present an alternative process by which chemical reactions occur with the excitation of vibrational levels in the ground electronic state by red solar photons. We focus on the O–H vibrational manifold which can be an atmospheric chromophore for driving vibrationally mediated overtone-induced chemical reactions. Experimental and theoretical O–H intensities of several carboxylic acids, alcohols, and peroxides are presented. The importance of combination bands in spectra at chemically relevant energies is examined in the context of atmospheric photochemistry. Candidate systems for overtone-initiated chemistry are provided, and their lowest energy barrier for reaction and the minimum quanta of O–H stretch required for reaction are calculated. We conclude with a discussion of the major pathways available for overtone-induced reactions in the atmosphere.

  17. Ankle-Dorsiflexion Range of Motion After Ankle Self-Stretching Using a Strap

    Science.gov (United States)

    Jeon, In-cheol; Kwon, Oh-yun; Yi, Chung-Hwi; Cynn, Heon-Seock; Hwang, Ui-jae

    2015-01-01

    Context  A variety of ankle self-stretching exercises have been recommended to improve ankle-dorsiflexion range of motion (DFROM) in individuals with limited ankle dorsiflexion. A strap can be applied to stabilize the talus and facilitate anterior glide of the distal tibia at the talocrural joint during ankle self-stretching exercises. Novel ankle self-stretching using a strap (SSS) may be a useful method of improving ankle DFROM. Objective  To compare the effects of 2 ankle-stretching techniques (static stretching versus SSS) on ankle DFROM. Design  Randomized controlled clinical trial. Setting  University research laboratory. Patients or Other Participants  Thirty-two participants with limited active dorsiflexion (<20°) while sitting (14 women and 18 men) were recruited. Main Outcome Measure(s)  The participants performed 2 ankle self-stretching techniques (static stretching and SSS) for 3 weeks. Active DFROM (ADFROM), passive DFROM (PDFROM), and the lunge angle were measured. An independent t test was used to compare the improvements in these values before and after the 2 stretching interventions. The level of statistical significance was set at α = .05. Results  Active DFROM and PDFROM were greater in both stretching groups after the 3-week interventions. However, ADFROM, PDFROM, and the lunge angle were greater in the SSS group than in the static-stretching group (P < .05). Conclusions  Ankle SSS is recommended to improve ADFROM, PDFROM, and the lunge angle in individuals with limited DFROM. PMID:26633750

  18. Acute effect of stretching one leg on regional arterial stiffness in young men.

    Science.gov (United States)

    Yamato, Yosuke; Hasegawa, Natsuki; Fujie, Shumpei; Ogoh, Shigehiko; Iemitsu, Motoyuki

    2017-06-01

    Our previous study demonstrated that a single bout of stretching exercises acutely reduced arterial stiffness. We hypothesized that this acute vascular response is due to regional mechanical stimulation of the peripheral arteries. To test this hypothesis, we examined the effect of a single bout of passive one leg stretching on arterial stiffness, comparing the stretched and the non-stretched leg in the same subject. Twenty-five healthy young men (20.9 ± 0.3 years, 172.5 ± 1.4 cm, 64.1 ± 1.2 kg) volunteered for the study. Subjects underwent a passive calf stretching on one leg (six repetitions of 30-s static stretch with a 10-s recovery). Pulse wave velocity (PWV, an index of arterial stiffness), blood pressure (BP), and heart rate (HR) were measured before and immediately, 15, and 30 min after the stretching. Femoral-ankle PWV (faPWV) in the stretched leg was significantly decreased from baseline (835.0 ± 15.9 cm/s) to immediately (802.9 ± 16.8 cm/s, P leg was not significantly altered at any time. Brachial-ankle PWV (baPWV) also showed similar responses with faPWV, but this response was not significant. Additionally, the passive stretching did not alter carotid-femoral PWV (cfPWV). These results suggest that mechanical stimulation to peripheral arteries as induced by static passive stretch may modulate arterial wall properties directly, rather than resulting in a systemic effect.

  19. Secondary structure estimation and properties analysis of stretched Asian and Caucasian hair.

    Science.gov (United States)

    Zhou, A J; Liu, H L; Du, Z Q

    2015-02-01

    In this previous work, we investigated the secondary structure changes of stretched yak hairs by deconvolution, secondary derivation, and curve fitting and determined the number of bands and their positions in order to resolve the protein spectrum of Raman spectroscopy. The secondary structure estimation and properties analysis of stretched Asian and Caucasian hair were investigated by Fourier transform infrared spectroscopy, tensile curves, and measurement of density. The hairs were stretched, dried, and baked at ratios 20%, 40%, 60%, 80% and 100%. The analysis of the amide I band indicated that the transformation from α-helix to β-pleated structure occurred during the stretching process, which could be verified from the tensile analysis. The cysteine oxide in S-O vibration area exhibited that stretching led to the breakage of the disulfide bonds. When the stretching ratio of Caucasian hair was more than a certain ratio, the fiber macromolecular structure was destroyed because Caucasian hair had finer diameter and less medulla than Asian hair. The β turn was easier to retract compared with other conformations, resulted in the content increase. The density measurements revealed that the structure of Caucasian hair was indeed more destroyed than that of Asian hair. The cuticles characterization indicated the length of scales was stretched longer and the thickness became thinner. Caucasian hair tended to collapse to form small fragments at the early stage of stretching. With the increase in stretching ratio, the scales of Caucasian hair lifted up, then flaked off and the scale interval increased accordingly. Asian hair was more easily peeled off than Caucasian hair cuticles with the increase in stretching ratio. The secondary structure of Caucasian hair was destroyed more easily than that of Asian hair. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Effects of Contract-Relax, Static Stretching, and Isometric Contractions on Muscle-Tendon Mechanics.

    Science.gov (United States)

    Kay, Anthony D; Husbands-Beasley, Jade; Blazevich, Anthony J

    2015-10-01

    Loading characteristics of stretching techniques likely influence the specific mechanisms responsible for acute increases in range of motion (ROM). Therefore, the effects of a version of contract-relax (CR) proprioceptive neuromuscular facilitation stretching, static stretching (SS), and maximal isometric contraction (Iso) interventions were studied in 17 healthy human volunteers. Passive ankle moment was recorded on an isokinetic dynamometer, with EMG recording from the triceps surae, simultaneous real-time motion analysis, and ultrasound-imaging-recorded gastrocnemius medialis muscle and Achilles tendon elongation. Subjects then performed each intervention randomly on separate days before reassessment. Significant increases in dorsiflexion ROM (2.5°-5.3°; P muscle-tendon stiffness (10.1%-21.0%; P stretching (P stretching and Iso (17.7%-22.1%; P 0.05), whereas significant reductions in muscle stiffness occurred after CR stretching and SS (16.0%-20.5%; P 0.05). Increases in peak passive moment (stretch tolerance) occurred after Iso (6.8%; P stretching (10.6%; P = 0.08), and SS (5.2%; P = 0.08); no difference in changes between conditions was found (P > 0.05). Significant correlations (rs = 0.69-0.82; P muscle and tendon stiffness are distinct. Concomitant reductions in muscle and tendon stiffness after CR stretching suggest a broader adaptive response that likely explains its superior efficacy in acutely increasing ROM. Although mechanical changes appear tissue-specific between interventions, similar increases in stretch tolerance after all interventions are strongly correlated with changes in ROM.

  1. Negative effect of static stretching restored when combined with a sport specific warm-up component.

    Science.gov (United States)

    Taylor, Kristie-Lee; Sheppard, Jeremy M; Lee, Hamilton; Plummer, Norma

    2009-11-01

    There is substantial evidence that static stretching may inhibit performance in strength and power activities. However, most of this research has involved stretching routines dissimilar to those practiced by athletes. The purpose of this study was to evaluate whether the decline in performance normally associated with static stretching pervades when the static stretching is conducted prior to a sport specific warm-up. Thirteen netball players completed two experimental warm-up conditions. Day 1 warm-up involved a submaximal run followed by 15 min of static stretching and a netball specific skill warm-up. Day 2 followed the same design; however, the static stretching was replaced with a 15 min dynamic warm-up routine to allow for a direct comparison between the static stretching and dynamic warm-up effects. Participants performed a countermovement vertical jump and 20m sprint after the first warm-up intervention (static or dynamic) and also after the netball specific skill warm-up. The static stretching condition resulted in significantly worse performance than the dynamic warm-up in vertical jump height (-4.2%, 0.40 ES) and 20m sprint time (1.4%, 0.34 ES) (pwarm-up was preceded by static stretching or a dynamic warm-up routine. This suggests that the practice of a subsequent high-intensity skill based warm-up restored the differences between the two warm-up interventions. Hence, if static stretching is to be included in the warm-up period, it is recommended that a period of high-intensity sport-specific skills based activity is included prior to the on-court/field performance.

  2. The acute effect of static and dynamic stretching during warm-ups on anaerobic performance in trained women

    Directory of Open Access Journals (Sweden)

    rouhollah haghshenas

    2014-09-01

    Full Text Available The purpose of this study was to investigate effects of static stretching, dynamic stretching and no stretching methods on power and speed in volleyball players. Therefore, Twenty-four volleyball players (height: 173.29 ± 7.81 m; mass: 62.12 ± 8.73 kg; age: 22.66 ± 4.02 years; experience: 3.27 ± 6.37 were tested for speed performance using the 20 meter sprint test and also for power using vertical jump test after static stretching, dynamic stretching and no stretching. The results analyzed using ANOVA showed that There was a significant increase in height jump after dynamic stretching against static stretching. But, there were no significant differences between no stretching and static stretching groups. In addition, there was a significant decrease in time 20 meter sprint after dynamic stretching against static stretching and no stretching groups. The results of this study suggest that it may be desirable for volleyball players to perform dynamic exercises before the performance of activities that require a high power output.

  3. Stretched exponential relaxation in molecular and electronic glasses

    International Nuclear Information System (INIS)

    Phillips, J.C.

    1996-01-01

    Stretched exponential relaxation, exp[-(t/τ) β ], fits many relaxation processes in disordered and quenched electronic and molecular systems, but it is widely believed that this function has no microscopic basis, especially in the case of molecular relaxation. For electronic relaxation the appearance of the stretched exponential is often described in the context of dispersive transport, where β is treated as an adjustable parameter, but in almost all cases it is generally assumed that no microscopic meaning can be assigned to 0 g , a glass transition temperature. We show that for molecular relaxation β(T g ) can be understood, providing that one separates extrinsic and intrinsic effects, and that the intrinsic effects are dominated by two magic numbers, β SR =3/5 for short-range forces, and β K =3/7 for long-range Coulomb forces, as originally observed by Kohlrausch for the decay of residual charge on a Leyden jar. Our mathematical model treats relaxation kinetics using the Lifshitz-Kac-Luttinger diffusion to traps depletion model in a configuration space of effective dimensionality, the latter being determined using axiomatic set theory and Phillips-Thorpe constraint theory. The experiments discussed include ns neutron scattering experiments, particularly those based on neutron spin echoes which measure S(Q, t) directly, and the traditional linear response measurements which span the range from μs to s, as collected and analysed phenomenologically by Angell, Ngai, Boehmer and others. The electronic materials discussed include a-Si:H, granular C 60 , semiconductor nanocrystallites, charge density waves in TaS 3 , spin glasses, and vortex glasses in high-temperature semiconductors. The molecular materials discussed include polymers, network glasses, electrolytes and alcohols, Van der Waals supercooled liquids and glasses, orientational glasses, water, fused salts, and heme proteins. In the intrinsic cases the theory of β(T g ) is often accurate to 2%, which

  4. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

    Science.gov (United States)

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-01-01

    The aim of this study was to investigate if static and dynamic stretching exercises of the knee muscles (quadriceps and hamstring muscles) have any effects on concentric and eccentric isokinetic peak torques and electromyographic amplitudes (EMG) of the antagonist muscles. Twenty healthy male athletes (age between 18-30 years) voluntarily participated in this study. All of the subjects visited the laboratory to complete the following intervention in a randomized order on 5 separate days; (a) non-stretching (control), (b) static stretching of the quadriceps muscles, (c) static stretching of the hamstring muscles, (d) dynamic stretching of the quadriceps muscles, and (e) dynamic stretching of the hamstring muscles. Static stretching exercises either for the quadriceps or the hamstring muscles were carried out at the standing and sitting positions. Subjects performed four successive repetitions of each stretching exercises for 30 seconds in both stretching positions. Similar to static stretching exercises two different stretching modes were designed for dynamic stretching exercises. Concentric and eccentric isokinetic peak torque for the non-stretched antagonist quadriceps or hamstring muscles at angular velocities of 60°/sec and 240°/sec and their concurrent electromyographic (EMG) activities were measured before and immediately after the intervention. Isokinetic peak torques of the non-stretched agonist hamstring and quadriceps muscles did not represent any significant (p > 0.05) differences following static and dynamic stretching of the antagonist quadriceps and hamstring muscles, respectively. Similarly, the EMG activities of the agonist muscles exhibited no significant alterations (p > 0.05) following both stretching exercises of the antagonist muscles. According to the results of the present study it is possible to state that antagonist stretching exercises either in the static or dynamic modes do not affect the isokinetic peak torques and the EMG activities

  5. The purinergic component of human bladder smooth muscle cells’ proliferation and contraction under physiological stretch

    Energy Technology Data Exchange (ETDEWEB)

    Wazir, Romel; Luo, De-Yi; Tian, Ye; Yue, Xuan; Li, Hong; Wang, Kun-Jie, E-mail: kunjiewangatscu@163.com

    2013-07-26

    Highlights: •Stretch induces proliferation and contraction. •Optimum applied stretch in vitro is 5% and 10% equibiaxial stretching respectively. •Expression of P2X1 and P2X2 is upregulated after application of stretch. •P2X2 is possibly more susceptible to stretch related changes. •Purinoceptors functioning may explain conditions with atropine resistance. -- Abstract: Objective: To investigate whether cyclic stretch induces proliferation and contraction of human smooth muscle cells (HBSMCs), mediated by P2X purinoceptor 1 and 2 and the signal transduction mechanisms of this process. Methods: HBSMCs were seeded on silicone membrane and stretched under varying parameters; (equibiaxial elongation: 2.5%, 5%, 10%, 15%, 20%, 25%), (Frequency: 0.05 Hz, 0.1 Hz, 0.2 Hz, 0.5 Hz, 1 Hz). 5-Bromo-2-deoxyuridine assay was employed for proliferative studies. Contractility of the cells was determined using collagen gel contraction assay. After optimal physiological stretch was established; P2X1 and P2X2 were analyzed by real time polymerase chain reaction and Western Blot. Specificity of purinoceptors was maintained by employing specific inhibitors; (NF023 for P2X1, and A317491for P2X2), in some experiments. Results: Optimum proliferation and contractility were observed at 5% and 10% equibiaxial stretching respectively, applied at a frequency of 0.1 Hz; At 5% stretch, proliferation increased from 0.837 ± 0.026 (control) to 1.462 ± 0.023%, p < 0.05. Mean contraction at 10% stretching increased from 31.7 ± 2.3%, (control) to 78.28 ±1.45%, p < 0.05. Expression of P2X1 and P2X2 was upregulated after application of stretch. Inhibition had effects on proliferation (1.232 ± 0.051, p < 0.05 NF023) and (1.302 ± 0.021, p < 0.05 A314791) while contractility was markedly reduced (68.24 ± 2.31, p < 0.05 NF023) and (73.2 ± 2.87, p < 0.05 A314791). These findings shows that mechanical stretch can promote magnitude-dependent proliferative and contractile modulation of HBSMCs in

  6. Electrical anharmonicity and dampings contributions to Cl-H → stretching band in gaseous (CH3)2O…HCl complex: Quantum dynamic study and prediction of the temperature effects

    Science.gov (United States)

    Rekik, Najeh; Alshammari, Majid F.

    2017-06-01

    In a previous work (Rekik et al., 2017), we demonstrated the ability of a simple anharmonic model of the dipole moment function of the X-H stretching band to explain a set of spectroscopic features of hydrogen bonding formation. Within the context of this model, we have shown that the origins of the broadening of the X - H → stretching band is attributed to large terms in the expansion of the autocorrelation functions due to the electrical anharmonicity. However, the question remained as to the ability of this model to treat the more complex situation in which we take into account the relaxation mechanisms that look at the effect of the surroundings and thereby gives rise to signatures of the medium to the X - H → stretching band lineshapes. Thus, in the present study, we investigated this situation by envisaging that the direct relaxation mechanism is due to the coupling between the fluctuating local electric field and the dipole moment of the complex as rationalized by Rosh and Ratner and the indirect damping resulting from the interaction of the X - H → stretch with its environment via the H-bond bridge mode. Theoretical experiments show that mixing of all these effects results in a speard and complicated structure. Using an ensemble of physically sound parameters as input into this approach, we have captured the main features in the experimental Cl - H → band in gaseous (CH3)2O…HCl complex and shown that the direct relaxation entrains a broadening of the spectra and is capable of qualitatively capturing the main features in the experimental spectra and quantitatively capturing the characteristic time scale of the vibrational dynamics of the Cl - H → stretching band. Furthermore, due to the decent agreement obtained between the theoretical and experimental line shapes at 226 K, the evolution of the IR spectra with the varaiation of temperature is proposed. The findings gained herein underscore the utility of combining simultaneously the effects of

  7. Quantifying stretching and rearrangement in epithelial sheet migration

    International Nuclear Information System (INIS)

    Lee, Rachel M; Nordstrom, Kerstin N; Losert, Wolfgang; Kelley, Douglas H; Ouellette, Nicholas T

    2013-01-01

    Although understanding the collective migration of cells, such as that seen in epithelial sheets, is essential for understanding diseases such as metastatic cancer, this motion is not yet as well characterized as individual cell migration. Here we adapt quantitative metrics used to characterize the flow and deformation of soft matter to contrast different types of motion within a migrating sheet of cells. Using a finite-time Lyapunov exponent (FTLE) analysis, we find that—in spite of large fluctuations—the flow field of an epithelial cell sheet is not chaotic. Stretching of a sheet of cells (i.e. positive FTLE) is localized at the leading edge of migration and increases when the cells are more highly stimulated. By decomposing the motion of the cells into affine and non-affine components using the metric D m in 2 , we quantify local plastic rearrangements and describe the motion of a group of cells in a novel way. We find an increase in plastic rearrangements with increasing cell densities, whereas inanimate systems tend to exhibit less non-affine rearrangements with increasing density. (paper)

  8. GRAVITATIONALLY UNSTABLE FLAMES: RAYLEIGH-TAYLOR STRETCHING VERSUS TURBULENT WRINKLING

    International Nuclear Information System (INIS)

    Hicks, E. P.; Rosner, R.

    2013-01-01

    In this paper, we provide support for the Rayleigh-Taylor-(RT)-based subgrid model used in full-star simulations of deflagrations in Type Ia supernovae explosions. We use the results of a parameter study of two-dimensional direct numerical simulations of an RT unstable model flame to distinguish between the two main types of subgrid models (RT or turbulence dominated) in the flamelet regime. First, we give scalings for the turbulent flame speed, the Reynolds number, the viscous scale, and the size of the burning region as the non-dimensional gravity (G) is varied. The flame speed is well predicted by an RT-based flame speed model. Next, the above scalings are used to calculate the Karlovitz number (Ka) and to discuss appropriate combustion regimes. No transition to thin reaction zones is seen at Ka = 1, although such a transition is expected by turbulence-dominated subgrid models. Finally, we confirm a basic physical premise of the RT subgrid model, namely, that the flame is fractal, and thus self-similar. By modeling the turbulent flame speed, we demonstrate that it is affected more by large-scale RT stretching than by small-scale turbulent wrinkling. In this way, the RT instability controls the flame directly from the large scales. Overall, these results support the RT subgrid model.

  9. Theoretical evidence for bond stretch isomerism in Grubbs olefin metathesis.

    Science.gov (United States)

    Remya, Premaja R; Suresh, Cherumuttathu H

    2017-07-15

    A comprehensive density functional theory study on the dissociative and associative mechanisms of Grubbs first and second generation olefin metathesis catalysis reveals that ruthenacyclobutane intermediate (RuCB) observed in the Chauvin mechanism is not unique as it can change to a non-metathetic ruthenacyclobutane (RuCB') via the phenomenon of bond stretch isomerism (BSI). RuCB and RuCB' differ mainly in RuC α , RuC β , and C α C β bond lengths of the metallacycle. RuCB is metathesis active due to the agostic type bonding-assisted simultaneous activation of both C α C β bonds, giving hypercoordinate character to C β whereas an absence of such bonding interactions in RuCB' leads to typical CC single bond distances and metathesis inactivity. RuCB and RuCB' are connected by a transition state showing moderate activation barrier. The new mechanistic insights invoking BSI explains the non-preference of associative mechanism and the requirement of bulky ligands in the Grubbs catalyst design. The present study lifts the status of BSI from a concept of largely theoretical interest to a phenomenon of intense importance to describe an eminent catalytic reaction. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  10. Extrinsic stretching narrowing and anterior indentation of the rectosigmoid junction

    International Nuclear Information System (INIS)

    Schulman, A.; Fataar, S.

    1979-01-01

    Thirty-five cases of extrinsic narrowing or anterior indentation of the rectosigmoid junction (RSJ) have been studied. The RSJ lies directly behind the pouch of Douglas which is a favoured site for peritoneal metastasis, abscess and endometriosis. Any space-occupying lesion of sufficient size at this site will indent the anterior aspects of the RSJ. Causes include distension or tumour of the ileum or sigmoid colon, gross ascites (when the patient is erect), and tumours below the pelvic peritonium, such as gynaecological neoplasm and internal iliac artery aneurysm. When a desmoplastic metastasis in the pouch of Douglas infiltrates the outer layers of the RSJ, the fibrosis produces an eccentric shortening on its anterior aspect, which in turn causes a pleating of the mucosa with the folds radiating towards the shortened area. This is also seen with primary pelvic carcinomas directly adherent to the rectum, endometriosis with repeated bleeding and increasing eccentric, submucosal fibrosis, and chronic abscess in the pouch of Douglas. Not all extrinsic narrowing of the RSJ are pathological. One case of anterior indentation followed operation for rectal prolapse. Ten additional cases showed narrowing due to a technical artefact air-distended colon rising into the upper abdomen to cause stretching at the RSJ. As with ascites, this narrowing due to 'high-rise sigmoid' disappeared when the patients became recumbent and the colonic air redistributed. (author)

  11. Stretch-activated cation channel from larval bullfrog skin

    DEFF Research Database (Denmark)

    Hillyard, Stanley D; Willumsen, Niels J; Marrero, Mario B

    2010-01-01

    Cell-attached patches from isolated epithelial cells from larval bullfrog skin revealed a cation channel that was activated by applying suction (-1 kPa to -4.5 kPa) to the pipette. Activation was characterized by an initial large current spike that rapidly attenuated to a stable value and showed...... was markedly reduced with N-methyl-D-glucamide (NMDG)-Cl Ringer's solution in the pipette. Neither amiloride nor ATP, which are known to stimulate an apical cation channel in Ussing chamber preparations of larval frog skin, produced channel activation nor did these compounds affect the response to suction....... Stretch activation was not affected by varying the pipette concentrations of Ca(2+) between 0 mmol l(-1) and 4 mmol l(-1) or by varying pH between 6.8 and 8.0. However, conductance was reduced with 4 mmol l(-1) Ca(2+). Western blot analysis of membrane homogenates from larval bullfrog and larval toad skin...

  12. Modulation of TRESK background K+ channel by membrane stretch.

    Directory of Open Access Journals (Sweden)

    Gerard Callejo

    Full Text Available The two-pore domain K(+ channel TRESK is expressed in dorsal root ganglion and trigeminal sensory neurons where it is a major contributor to background K(+ current. TRESK acts as a break to prevent excessive sensory neuron activation and decreases in its expression or function have been involved in neuronal hyperexcitability after injury/inflammation, migraine or altered sensory perception (tingling, cooling and pungent burning sensations. All these effects have implicated this channel in nociception and mechanotransduction. To determine the role of TRESK in sensory transduction, we studied its sensitivity to changes in membrane tension (stretch in heterologous systems, F-11 cells and trigeminal neurons. Laminar shear stress increased TRESK currents by 22-30%. An increase in membrane tension induced by cell swelling (hypotonic medium produced a reversible elevation of TRESK currents (39.9%. In contrast, cell shrinkage (hypertonic solution produced the opposite effect. Membrane crenators or cup-formers produced equivalent effects. In trigeminal sensory neurons, TRESK channels were mechanically stimulated by negative pressure, which led to a 1.51-fold increase in channel open probability. TRESK-like currents in trigeminal neurons were additively inhibited by arachidonic acid, acidic pH and hypertonic stimulation, conditions usually found after tissue inflammation. Our results show that TRESK is modulated by changes in cell membrane tension and/or cell volume. Several key players released during inflammation or tissue injury could modulate sensory neuron activation through small changes in membrane tension.

  13. Distributed sensing: multiple capacitive stretch sensors on a single channel

    Science.gov (United States)

    Tairych, Andreas; Anderson, Iain A.

    2017-04-01

    "Soft, stretchable, and unobtrusive". These are some of the attributes frequently associated with capacitive dielectric elastomer (DE) sensors for body motion capture. While the sensors themselves are soft and elastic, they require rigid peripheral components for capacitance measurement. Each sensor is connected to a separate channel on the sensing circuitry through its own set of wires. In wearable applications with large numbers of sensors, this can lead to a considerable circuit board footprint, and cumbersome wiring. The additional equipment can obstruct movement and alter user behaviour. Previous work has demonstrated how a transmission line model can be applied to localise deformation on a single DE sensor. Building on this approach, we have developed a distributed sensing method by arranging capacitive DE sensors and external resistors to form a transmission line, which is connected to a single sensing channel with only one set of wires. The sensors are made from conductive fabric electrodes, and silicone dielectrics, and the external resistors are off-the-shelf metal film resistors. Excitation voltages with different frequencies are applied to the transmission line. The lumped transmission line capacitances at these frequencies are passed on to a mathematical model that calculates individual sensor capacitance changes. The prototype developed for this study is capable of obtaining separate readings for simultaneously stretched sensors.

  14. Thin film flow along a periodically-stretched elastic beam

    Science.gov (United States)

    Boamah Mensah, Chris; Chini, Greg; Jensen, Oliver

    2017-11-01

    Motivated by an application to pulmonary alveolar micro-mechanics, a system of partial differential equations is derived that governs the motion of a thin liquid film lining both sides of an inertia-less elastic substrate. The evolution of the film mass distribution is described by invoking the usual lubrication approximation while the displacement of the substrate is determined by employing a kinematically nonlinear Euler-Bernoulli beam formulation. In the parameter regime of interest, the axial strain can be readily shown to be a linear function of arc-length specified completely by the motion of ends of the substrate. In contrast, the normal force balance on the beam yields an equation for the substrate curvature that is fully coupled to the time-dependent lubrication equation. Linear analyses of both a stationary and periodically-stretched flat substrate confirm the potential for buckling instabilities and reveal an upper bound on the dimensionless axial stiffness for which the coupled thin-film/inertial-less-beam model is well-posed. Numerical simulations of the coupled system are used to explore the nonlinear development of the buckling instabilities.

  15. Study of the shape of β spectra

    International Nuclear Information System (INIS)

    Bisch, Charlene

    2014-01-01

    The goal of this PhD work is to build an experimental device dedicated to measuring beta spectra with a precision relevant to modern metrology requirements. The device, which is based on a silicon semi-conductor detector, must take into account certain physical phenomena and detector characteristics which could lead to deformation of the measured spectra. These must be understood and minimized. Monte-Carlo simulations have allowed the geometry and construction materials to be optimized. The quality of the radioactive sources is paramount in obtaining spectra of high-quality. Nonetheless, the measured spectra must be corrected for any remaining distortion. A response function must therefore be determined for each measurement geometry. This can be achieved via Monte-Carlo simulations. The first results show that deconvolution of the measured spectra with the response function makes possible the accurate determination of the true form of the beta spectra. (author) [fr

  16. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H

    2002-01-01

    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  17. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  18. EFFECTIVENESS OF ECCENTRIC TRAINING, DYNAMIC RANGE OF MOTION EXERCISES AND STATIC STRETCHING ON FLEXIBILITY OF HAMSTRING MUSCLE AMONG FOOTBALL PLAYERS.

    OpenAIRE

    Askar P.V; Veena Pais; Nagarajan Mohan; Shaikhji Saad; Nusaibath M Shaikhji

    2015-01-01

    Background: Hamstring stretch is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examine the effect of eccentric training, static stretching and dynamic range of motion(DROM) exercise in improving hamstring flexibility this study compares the effect of eccentric training and static stretching in improving hamstring flexibility. The purpose of this study was to determine the effects of Eccentric training, Static stretching and Dy...

  19. Neutron and photon spectra in LINACs

    International Nuclear Information System (INIS)

    Vega-Carrillo, H.R.; Martínez-Ovalle, S.A.; Lallena, A.M.; Mercado, G.A.; Benites-Rengifo, J.L.

    2012-01-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 –6 and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage. - Highlights: ► With MCNPX code realistic models of two LINACs were built. ► Photon and neutron spectra below the flattening filter and at the isocenter were calculated. ► Neutron spectrum at the flattening filter was compared against the Tosi et al. source-term model. ► Tosi et al. model underestimates the neutron contribution below 1 MeV. ► Photon spectra look alike to those published in literature.

  20. Infrared spectra of thyroid tumor tissues

    Science.gov (United States)

    Tolstorozhev, G. B.; Skornyakov, I. V.; Butra, V. A.

    2010-07-01

    We used infrared spectroscopy methods to study thyroid tumor tissues removed during surgery. The IR spectra of the surgical material are compared with data from histological examination. We show that in malignant neoplasms, the spectra of proteins in the region of C=O vibrations are different from the spectra of these substances in benign tumors and in tissues outside the pathological focus at a distance >1 cm from the margin of the tumor. The differences in the spectra are due to changes in the supermolecular structure of the proteins, resulting from rearrangement of the system of hydrogen bonds. We identify the spectral signs of malignant pathologies.

  1. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  2. Reflectance spectra of subarctic lichens

    International Nuclear Information System (INIS)

    Petzold, D.E.; Goward, S.N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the mid latitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 μm, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future. (author)

  3. Reflectance spectra of subarctic lichens

    Science.gov (United States)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  4. Methodology for analyzing weak spectra

    International Nuclear Information System (INIS)

    Yankovich, T.L.; Swainson, I.P.

    2000-02-01

    There is considerable interest in quantifying radionuclide transfer between environmental compartments. However, in many cases, it can be a challenge to detect concentrations of gamma-emitting radionuclides due to their low levels in environmental samples. As a result, it is valuable to develop analytical protocols to ensure consistent analysis of the areas under weak peaks. The current study has focused on testing how reproducibly peak areas and baselines can be determined using two analytical approaches. The first approach, which can be carried out using Maestro software, involves extracting net counts under a curve without fitting a functional form to the peak, whereas the second approach, which is used by most other peak fitting programs, determines net counts from spectra by fitting a Gaussian form to the data. It was found that the second approach produces more consistent peak area and baseline measurements, with the ability to de-convolute multiple, overlapping peaks. In addition, programs, such as Peak Fit, which can be used to fit a form to spectral data, often provide goodness of fit analyses, since the Gaussian form can be described using a characteristic equation against which peak data can be tested for their statistical significance. (author)

  5. Does vibration counteract the static stretch-induced deficit on muscle force development?

    Science.gov (United States)

    Fernandes, Igor Alexandre; Kawchuk, Gregory; Bhambhani, Yagesh; Gomes, Paulo Sergio Chagas

    2013-09-01

    To determine the residual acute vibration-stretching effect on preactivation levels, short-latency stretch reflex, and performance during execution of drop jumps. Repeated measures. Eleven male recreational athletes performed a set of three 45cm drop jumps before and immediately after a 30s static stretching exercise with and without simultaneously imposed muscle vibration (45Hz, 5mm). Drop jump height, ground reaction forces and electromyographic data including Vastus Lateralis onset/levels of preactivation and short-latency stretch reflex were recorded. No changes were induced on drop jump height. However, stretching-induced decrements on ground reaction force peak and time to peak as well as an increment in contact time followed a delay in short-latency stretch reflex onset and a reduced preactivation level of Vastus Lateralis. Otherwise, when vibration was simultaneously imposed, there was no evidence of changes in high-speed force production variables or electromyographic recordings. Mechanical vibration, when applied simultaneously to static-stretching routines, appeared to be effective to counteract decreased musculotendinous unit stiffness-induced high-speed force production deficit during jumping performance. Copyright © 2012. Published by Elsevier Ltd.

  6. A Variable Resolution Stretched Grid General Circulation Model: Regional Climate Simulation

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Takacs, Lawrence L.; Govindaraju, Ravi C.; Suarez, Max J.

    2000-01-01

    The development of and results obtained with a variable resolution stretched-grid GCM for the regional climate simulation mode, are presented. A global variable resolution stretched- grid used in the study has enhanced horizontal resolution over the U.S. as the area of interest The stretched-grid approach is an ideal tool for representing regional to global scale interaction& It is an alternative to the widely used nested grid approach introduced over a decade ago as a pioneering step in regional climate modeling. The major results of the study are presented for the successful stretched-grid GCM simulation of the anomalous climate event of the 1988 U.S. summer drought- The straightforward (with no updates) two month simulation is performed with 60 km regional resolution- The major drought fields, patterns and characteristics such as the time averaged 500 hPa heights precipitation and the low level jet over the drought area. appear to be close to the verifying analyses for the stretched-grid simulation- In other words, the stretched-grid GCM provides an efficient down-scaling over the area of interest with enhanced horizontal resolution. It is also shown that the GCM skill is sustained throughout the simulation extended to one year. The developed and tested in a simulation mode stretched-grid GCM is a viable tool for regional and subregional climate studies and applications.

  7. A study of extracellular matrix remodeling in aortic heart valves using a novel biaxial stretch bioreactor.

    Science.gov (United States)

    Lei, Ying; Masjedi, Shirin; Ferdous, Zannatul

    2017-11-01

    In aortic valves, biaxial cyclic stretch is known to modulate cell differentiation, extracellular matrix (ECM) synthesis and organization. We designed a novel bioreactor that can apply independent and precise stretch along radial and circumferential directions in a tissue culture environment. While this bioreactor can be used for either native or engineered tissues, this study determined matrix remodeling and strain distribution of aortic cusps after culturing under biaxial stretch for 14 days. The contents of collagen and glycosaminoglycans were determined using standard biochemical assays and compared with fresh controls. Strain fields in static cusps were more uniform than those in stretched cusps, which indicated degradation of the ECM fibers. The glycosaminoglycan content was significantly elevated in the static control as compared to fresh or stretched cusps, but no difference was observed in collagen content among the groups. The strain profile of freshly isolated fibrosa vs. ventricularis and left, right, and noncoronary cusps were also determined by Digital Image Correlation technique. Distinct strain patterns were observed under stretch on fibrosa and ventricularis sides and among the three cusps. This work highlights the critical role of the anisotropic ECM structure for proper functions of native aortic valves and the beneficial effects of biaxial stretch for maintenance of the native ECM structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Effects of cryotherapy and thermotherapy associated with static stretching on the flexibility of hamstring muscles

    Directory of Open Access Journals (Sweden)

    S.A. Silva

    2010-01-01

    Full Text Available The objective of the present study was to analyze the effect of cryotherapy and muscular warming on the flexibility of the hamstring muscles associated with three minutes of static stretching. Forty young male and female volunteers were randomly included in one of four groups: Group 1 – Control group, Group 2 – Three minutes of static stretching, Group 3 – Stretching preceded by warming using shortwave diathermy (20 minutes, and Group 4 – Stretching preceded by applying cryotherapy (20 minutes to the posterior thigh region. The program consisted of three series of stretching during five consecutive days and flexibility was assessed by goniometric evaluations of the extensor angle of the knee at the beginning of the protocol, at the end of the day and at the end of the protocol. The intergroup comparison was made through ANOVA post-hoc Tukey and the intragroup by paired t test, all with 5% level of significance. The three experimental groups significantly increased their range of motion in relation to the control group. However, differences were not observed among groups submitted to the different stretching programs. In conclusion, increases in flexibility were due to stretching and did not depend on previous application of hyperthermia and/or hypothermia.

  9. Fast-crawling cell types migrate to avoid the direction of periodic substratum stretching.

    Science.gov (United States)

    Okimura, Chika; Ueda, Kazuki; Sakumura, Yuichi; Iwadate, Yoshiaki

    2016-07-03

    To investigate the relationship between mechanical stimuli from substrata and related cell functions, one of the most useful techniques is the application of mechanical stimuli via periodic stretching of elastic substrata. In response to this stimulus, Dictyostelium discoideum cells migrate in a direction perpendicular to the stretching direction. The origins of directional migration, higher migration velocity in the direction perpendicular to the stretching direction or the higher probability of a switch of migration direction to perpendicular to the stretching direction, however, remain unknown. In this study, we applied periodic stretching stimuli to neutrophil-like differentiated HL-60 cells, which migrate perpendicular to the direction of stretch. Detailed analysis of the trajectories of HL-60 cells and Dictyostelium cells obtained in a previous study revealed that the higher probability of a switch of migration direction to that perpendicular to the direction of stretching was the main cause of such directional migration. This directional migration appears to be a strategy adopted by fast-crawling cells in which they do not migrate faster in the direction they want to go, but migrate to avoid a direction they do not want to go.

  10. Retinal glial (Müller ) cells: sensing and responding to tissue stretch.

    Science.gov (United States)

    Lindqvist, Niclas; Liu, Qing; Zajadacz, Joachim; Franze, Kristian; Reichenbach, Andreas

    2010-03-01

    To test whether Müller glial cells sense, and respond to, mechanical tension in the retina. A device was designed to stretch the retina at right angles to its surface, across retinal layers. Pieces of retina were mounted between two hollow tubes, and uniaxial force was applied to the tissue using a micrometer-stepping motor. Müller cells were selectively stained with the fluorescent, calcium-sensitive dye X-Rhod-1 and were monitored in real time during retinal stretch in vitro. Immunohistochemistry was used to study protein levels and activation of intracellular pathways in stretched retinas. Müller cells responded acutely with transient increases in fluorescence during stretch, indicative of increased intracellular calcium levels. All the Müller cells elongated uniformly, and there was no apparent difference between retinal layers in resistance against mechanical deformation. After stretch, Müller cells showed fast activation of extracellular signal-regulated kinase (after 15 minutes), upregulation of transcription factor c-Fos (after 1 hour), and basic fibroblast growth factor (after 3 hours). No changes in intermediate filament protein expression were observed in Müller cells up to 3 hours after stretch. A novel technique was developed for real-time monitoring of Müller cells during retinal stretch, which allowed the identification of Müller cells as a mechanoresponsive cell type. Mechanical stress triggers molecular responses in Müller cells that could prevent retinal damage.

  11. A comparison of two stretching programs for hamstring muscles: A randomized controlled assessor-blinded study.

    Science.gov (United States)

    Demoulin, Christophe; Wolfs, Sébastien; Chevalier, Madeline; Granado, Caroline; Grosdent, Stéphanie; Depas, Yannick; Roussel, Nathalie; Hage, Renaud; Vanderthommen, Marc

    2016-01-01

    Most parameters regarding hamstring flexibility training programs have been investigated; however, the joint (i.e. hip or knee) on which the stretching should preferentially be focused needs to be further explored. This randomized controlled assessor-blinded study aimed to investigate the influence of this parameter. We randomly assigned 111 asymptomatic participants with tight hamstring muscles in three groups: a control group and two groups following a different home-based 8-week (five 10-minute sessions per week) hamstring stretching program (i.e. stretching performed by flexing the hip while keeping the knee extended [SH] or by first flexing the hip with a flexed knee and then extending the knee [SK]). Range of motion (ROM) of hip flexion and knee extension were measured before and after the stretching program by means of the straight leg raising test and the passive knee extension angle test, respectively. Eighty-nine participants completed the study. A significant increase in ROM was observed at post-test. Analyses showed significant group-by-time interactions for changes regarding all outcomes. Whereas the increase in hip flexion and knee extension ROM was higher in the stretching groups than in the CG (especially for the SH group p 0.05). In conclusion, the fact that both stretching programs resulted in similar results suggests no influence of the joint at which the stretching is focused upon, as assessed by the straight leg raising and knee extension angle tests.

  12. Effects of Static Stretching Exercise on Lumbar Flexibility and Central Arterial Stiffness.

    Science.gov (United States)

    Logan, Jeongok G; Kim, Suk-Sun; Lee, Mijung; Byon, Ha Do; Yeo, SeonAe

    2018-01-23

    Previous studies have demonstrated that arterial stiffness is associated with lumbar flexibility (LF). Stretching exercise targeted to improve LF may have a beneficial effect on reducing arterial stiffness. We examined the effects of a single bout of a structured, static stretching exercise on arterial stiffness, LF, peripheral and central blood pressure (BP), and heart rate (HR) and tested the association between LF and central arterial stiffness. The study had a pretest-posttest design without a control group. Thirty healthy women followed a video demonstration of a 30-minute whole-body stretching exercise. Carotid-femoral pulse wave velocity (cf-PWV), augmentation index, LF, peripheral and central BP, and HR were measured before and after the stretching exercise. One bout of a static stretching exercise significantly reduced cf-PWV (t29 = 2.708, P = .011) and HR (t29 = 7.160, P = .000) and increased LF (t29 = 12.248, P static stretching exercise on central arterial stiffness, an independent predictor of cardiovascular morbidity. Static stretching exercise conducted in the sitting position may be used as an effective intervention to reduce cardiovascular risk after a cardiac event or for patients whose sympathetic function should not be overly activated or whose gaits are not stable.

  13. Warm-up effects from concomitant use of vibration and static stretching after cycling.

    Science.gov (United States)

    Yang, Wen-Wen; Liu, Chiang; Shiang, Tzyy-Yuang

    2017-04-01

    Static stretch is routinely used in traditional warm-up but impaired muscle performance. Combining vibration with static stretching as a feasible component may be an alternative to static stretching after submaximal aerobic exercise to improve jumping as well as flexibility. Therefore, the purpose of this study was to investigate and compare the effects of aerobic exercise, static stretching, and vibration with static stretching on flexibility and vertical jumping performance. A repeated measures experimental design was used in this study. Twelve participants randomly underwent 5 different warm-ups including cycling alone (C warm-up), static stretching alone (S warm-up), combining vibration with static stretching (VS warm-up), cycling followed by S (C+S warm-up), and cycling followed by VS (C+VS warm-up) on 5 separate days. Sit-and-reach, squat jump (SJ), and counter movement jump (CMJ) were measured for pre- and post- tests. The sit-and-reach scores after the S, VS, C+S and C+VS warm-ups were significantly enhanced (Pafter the C and C+VS warm-ups were significantly increased (Pafter the S warm-up (Pstretching after submaximal cycling exercise (C+VS warm-up) could be a feasible warm-up protocol to improve both flexibility and vertical jump performance, compared with the traditional warm-up (C+S warm-up).

  14. Effects of Plantar Flexor Muscle Static Stretching Alone and Combined With Massage on Postural Balance.

    Science.gov (United States)

    Hemmati, Ladan; Rojhani-Shirazi, Zahra; Ebrahimi, Samaneh

    2016-10-01

    To evaluate and compare the effects of stretching and combined therapy (stretching and massage) on postural balance in people aged 50 to 65 years. Twenty-three subjects participated in this nonrandomized clinical trial study. Each participant randomly received plantar flexor muscle stretching (3 cycles of 45 seconds with a 30-second recovery period between cycles) alone and in combination with deep stroking massage (an interval of at least 30 minutes separated the two interventions). The data were recorded with a force platform immediately after each condition with eyes open and closed. The center of pressure displacement and velocity along the mediolateral and anteroposterior axes were calculated under each condition. The data were analyzed with multiple-pair t-tests. The center of pressure displacement and velocity along the mediolateral axis increased after both stretching and the combined intervention. There were significant differences in both values between participants in the stretching and combined interventions (pmuscle stretching (for 45 seconds) combined with deep stroking massage may have more detrimental effects on postural balance than stretching alone because each intervention can intensify the effects of the other.

  15. The acute benefits and risks of passive stretching to the point of pain.

    Science.gov (United States)

    Muanjai, Pornpimol; Jones, David A; Mickevicius, Mantas; Satkunskiene, Danguole; Snieckus, Audrius; Skurvydas, Albertas; Kamandulis, Sigitas

    2017-06-01

    This study evaluated the acute effects of two different stretch intensities on muscle damage and extensibility. Twenty-two physically active women (age 20 ± 1.0 years) were divided into two matched groups and undertook eight sets of 30-s passive hamstring stretching. One group stretched to the point of discomfort (POD) and the other to the point of pain (POP). Hamstring passive torque, sit and reach (S&R), straight leg raise (SLR), and markers of muscle damage were measured before, immediately after stretching and 24 h later. S&R acutely increased and was still increased at 24 h with median (interquartile range) of 2.0 cm (0.5-3.75 cm) and 2.0 cm (0.25-3.0 cm) for POP and POD (p muscle tenderness occurred at 24 h in both groups and there was a very small increase in thigh circumference in both groups which persisted at 24 h in POP. Plasma CK activity was not raised at 24 h. Stretching to the point of pain had no acute advantages over stretching to the discomfort point. Both forms of stretching resulted in very mild muscle tenderness but with no evidence of muscle damage. The increased ROM was not associated with changes in passive stiffness of the muscle but most likely resulted from increased tolerance of the discomfort.

  16. Muscle-specific acute changes in passive stiffness of human triceps surae after stretching.

    Science.gov (United States)

    Hirata, Kosuke; Miyamoto-Mikami, Eri; Kanehisa, Hiroaki; Miyamoto, Naokazu

    2016-05-01

    It remains unclear whether the acute effect of stretching on passive muscle stiffness differs among the synergists. We examined the muscle stiffness responses of the medial (MG) and lateral gastrocnemii (LG), and soleus (Sol) during passive dorsiflexion before and after a static stretching by using ultrasound shear wave elastography. Before and after a 5-min static stretching by passive dorsiflexion, shear modulus of the triceps surae and the Achilles tendon (AT) during passive dorsiflexion in the knee extended position were measured in 12 healthy subjects. Before the static stretching, shear modulus was the greatest in MG and smallest in Sol. The stretching induced significant reductions in shear modulus of MG, but not in shear modulus of LG and Sol. The slack angle was observed at more plantar flexed position in the following order: AT, MG, LG, and Sol. After the stretching, the slack angles of each muscle and AT were significantly shifted to more dorsiflexed positions with a similar extent. When considering the shift in slack angle, the change in MG shear modulus became smaller. The present study indicates that passive muscle stiffness differs among the triceps surae, and that the acute effect of a static stretching is observed only in the stiff muscle. However, a large part of the reduction of passive muscle stiffness at a given joint angle could be due to an increase in the slack length.

  17. Acute Effect of Different Combined Stretching Methods on Acceleration and Speed in Soccer Players

    Directory of Open Access Journals (Sweden)

    Amiri-Khorasani Mohammadtaghi

    2016-04-01

    Full Text Available The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up, on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height: 177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49 years was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min stretching program (except for the no-stretching protocol, and 2 min rest periods, followed by the 10 and 20 m sprint test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic stretching compared with static, combined, and no-stretching protocols. There were also significant differences between the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more force for a faster execution.

  18. Effects of static stretching on the hamstrings-to-quadriceps ratio and electromyographic amplitude in men.

    Science.gov (United States)

    Costa, P B; Ryan, E D; Herda, T J; Defreitas, J M; Beck, T W; Cramer, J T

    2009-12-01

    The purpose of this study was to examine the effects of posterior thigh and leg stretching on leg flexion peak torque (PT), leg extension PT, the hamstrings-to-quadriceps (H:Q) ratio, and electromyographic (EMG) amplitude of the hamstrings and quadriceps in recreationally-active men. Fifteen men (mean age + or - SD = 22.0 + or - 4.4 years; body mass = 82.7 + or - 16.1 kg; height = 173.1 + or - 6.8 cm) performed three maximal voluntary concentric isokinetic leg extension and flexion muscle actions at three randomly ordered angular velocities (60, 180, and 300 degrees x s(-1)) before and after hamstring and calf static stretching. The stretching protocol consisted of 1 unassisted and 3 assisted static stretching exercises designed to stretch the posterior muscles of the thigh and leg. Four repetitions of each stretch were held for 30 s with 20-s rest between repetitions. These findings indicated no significant (P>0.05) stretching-induced changes in leg flexion PT, leg extension PT, or EMG amplitude at 60, 180, or 300 degrees .s-1. However, the non-significant (P>0.05) 2-4% increases in leg extension PT combined with the non-significant (P>0.05) 1-2% decreases in leg flexion PT resulted in the significant (P ratio from pre- to post-stretching for all three velocities. These findings suggested that static stretching of the hamstrings and calf muscles may decrease the H:Q ratio. These results may be useful for athletic trainers, physical therapists, and other allied health professionals who may use the H:Q ratio as a clinical assessment.

  19. Acute effects of static and dynamic stretching on balance, agility, reaction time and movement time.

    Science.gov (United States)

    Chatzopoulos, Dimitris; Galazoulas, Christos; Patikas, Dimitrios; Kotzamanidis, Christos

    2014-05-01

    The purpose of this study was to compare the acute effects of three different stretching protocols on balance, agility, reaction time and movement time of the upper limbs. Participants were thirty one female high school athletes (age = 17.3 ± 0.5 yr.). All participants performed one of the following protocols on different days: (a) 3 min jogging followed by 7 min static stretching (SS), (b) 3 min jogging followed by 7 min dynamic stretching (DS), and (c) 3 min jogging followed by 7 min of rest (NS). After the protocols participants performed the following tests: dynamic balance, 505 agility test, reaction time (time between a sound stimulus and release of a button) and movement time (movement of the upper extremity over a 0.5 m distance). The order of stretching protocols and performance tests were counterbalanced to avoid carryover effects. Repeated measures analysis of variance revealed significant main effects for all variables except reaction time. The DS protocol compared to SS performed significantly better in balance, agility and movement time. Additionally, the DS protocol compared to NS performed significantly better in agility. According to the results of the study, a DS protocol is more appropriate than SS for activities that require balance, rapid change of running direction (agility) and movement time of the upper extremities. Key pointsStatic stretching has a negative effect on balance and agility performance compared to dynamic stretching.There was no effect of the stretching protocols on reaction time.Dynamic stretching was more effective than static stretching for increasing movement time of the upper extremities.

  20. Periostin inhibits mechanical stretch-induced apoptosis in osteoblast-like MG-63 cells.

    Science.gov (United States)

    Yu, Kai-Wen; Yao, Chung-Chen; Jeng, Jiiang-Huei; Shieh, Hao-Ying; Chen, Yi-Jane

    2018-04-01

    Appropriate mechanical stress plays an important role in regulating the proliferation and differentiation of osteoblasts, whereas high-level mechanical stress may be harmful and compromise cell survival. Periostin, a matricellular protein, is essential in maintaining functional integrity of bone and collagen-rich connective tissue in response to mechanical stress. This study investigated whether or not high-level mechanical stretch induces cell apoptosis and the regulatory role of periostin in mechanical stretch-induced apoptosis in osteoblastic cells. Osteoblast-like MG-63 cells were seeded onto Bio-Flex I culture plates and subjected to cyclic mechanical stretching (15% elongation, 0.1 Hz) in a Flexercell tension plus system-5000. The same process was applied to cells pre-treated with exogenous human recombinant periostin before mechanical stretching. We used a chromatin condensation and membrane permeability dead cell apoptosis kit to evaluate the stretch-induced cell responses. Expression of caspase-3 and cPARP was examined by immunofluorescent stain and flow cytometry. The expression of periostin in MG-63 cells is involved in the TGF-β signaling pathway. High-level cyclic mechanical stretch induced apoptotic responses in MG-63 osteoblastic cells. The percentages of apoptotic cells and cells expressing cPARP protein increased in the groups of cells subjected to mechanical stretch, but these responses were absent in the presence of exogenous periostin. Our study revealed that high-level mechanical stretch induces apoptotic cell death, and that periostin plays a protective role against mechanical stretch-induced apoptosis in osteoblastic cells. Copyright © 2017. Published by Elsevier B.V.