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Sample records for relaxation depends solely

  1. Density dependence of relaxation dynamics in glass formers, and ...

    Indian Academy of Sciences (India)

    Anshul D S Parmar

    formers, we study the variation of relaxation dynamics with density, rather than temperature, as a control ... stronger behaviour, the use of scaled variables involving temperature and ... of the temperature dependence of B as written defines.

  2. Field dependence of the electron spin relaxation in quantum dots.

    Science.gov (United States)

    Calero, Carlos; Chudnovsky, E M; Garanin, D A

    2005-10-14

    The interaction of the electron spin with local elastic twists due to transverse phonons is studied. The universal dependence of the spin-relaxation rate on the strength and direction of the magnetic field is obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid. The theory contains no unknown parameters and it can be easily tested in experiment. At high magnetic field it provides a parameter-free lower bound on the electron spin relaxation in quantum dots.

  3. Temperature dependence of the kinetics of isometric myocardium relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Izakov, V.Ya.; Bykov, B.L.; Kimmelman, I.Ya.

    1981-11-01

    The dependence of the exponential decay constant expressing the isometric relaxation of the myocardium on temperature is investigated in animals with various specific contents of myocardial sarcoplasmic reticulum. Experiments were performed on cardiac ventricles and atria isolated from rabbits, frogs and turtles and electrically stimulated to produce maximal contraction at temperatures from 10 to 35 C. Arrhenius plots derived from the data are found to be linear in the myocardia of the rabbit and frog, with a greater activation energy for the relaxation found in the rabbit. The Arrhenius plot for the turtle, which has a sarcoplasmic reticulum content intermediate between those of the frog and rabbit, corresponds to two straight lines with different activation energies. Results thus support the hypothesis of two separate mechanisms of calcium removal, involving the sarcoplasmic reticulum and cellular membrane, in muscle relaxation.

  4. Mechanisms underlying epithelium-dependent relaxation in rat bronchioles

    DEFF Research Database (Denmark)

    Kroigaard, Christel; Dalsgaard, Thomas; Simonsen, Ulf

    2010-01-01

    This study investigated the mechanisms underlying epithelium-derived hyperpolarizing factor (EpDHF)-type relaxation in rat bronchioles. Immunohistochemistry was performed, and rat bronchioles and pulmonary arteries were mounted in microvascular myographs for functional studies. An opener of small...... (SK(Ca)) and intermediate (IK(Ca))-conductance calcium-activated potassium channels, NS309 (6,7-dichloro-1H-indole-2,3-dione 3-oxime) was used to induce EpDHF-type relaxation. IK(Ca) and SK(Ca)3 positive immunoreactions were observed mainly in the epithelium and endothelium of bronchioles and arteries......, respectively. In 5-hydroxytryptamine (1 microM)-contracted bronchioles (828 +/- 20 microm, n = 84) and U46619 (0.03 microM)-contracted arteries (720 +/- 24 microm, n = 68), NS309 (0.001-10 microM) induced concentration-dependent relaxations that were reduced by epithelium/endothelium removal and by blocking IK...

  5. Time-Dependent Behaviors of Granite: Loading-Rate Dependence, Creep, and Relaxation

    Science.gov (United States)

    Hashiba, K.; Fukui, K.

    2016-07-01

    To assess the long-term stability of underground structures, it is important to understand the time-dependent behaviors of rocks, such as their loading-rate dependence, creep, and relaxation. However, there have been fewer studies on crystalline rocks than on tuff, mudstone, and rock salt, because the high strength of crystalline rocks makes the detection of their time-dependent behaviors much more difficult. Moreover, studies on the relaxation, temporal change of stress and strain (TCSS) conditions, and relations between various time-dependent behaviors are scarce for not only granites, but also other rocks. In this study, previous reports on the time-dependent behaviors of granites were reviewed and various laboratory tests were conducted using Toki granite. These tests included an alternating-loading-rate test, creep test, relaxation test, and TCSS test. The results showed that the degree of time dependence of Toki granite is similar to other granites, and that the TCSS resembles the stress-relaxation curve and creep-strain curve. A viscoelastic constitutive model, proposed in a previous study, was modified to investigate the relations between the time-dependent behaviors in the pre- and post-peak regions. The modified model reproduced the stress-strain curve, creep, relaxation, and the results of the TCSS test. Based on a comparison of the results of the laboratory tests and numerical simulations, close relations between the time-dependent behaviors were revealed quantitatively.

  6. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang; Liu, Taixiang; Liao, G J; Lubineau, Gilles

    2017-01-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  7. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang

    2017-09-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  8. Vogel-Fulcher dependence of relaxation rates in a nematic monomer and elastomer

    Science.gov (United States)

    Shenoy, D.; Filippov, S.; Aliev, F.; Keller, P.; Thomsen, D.; Ratna, B.

    2000-12-01

    Dielectric relaxation spectroscopy is used to study the relaxation processes in a nematic monomer and the corresponding cross-linked polymer nematic liquid crystal (elastomer). In the frequency window 10 mHz to 2 GHz the monomer liquid crystal shows a single relaxation whereas the polymer exhibits three relaxation processes, two of which are quantitatively analyzed. The temperature dependence of relaxation times in both the monomer and polymer follows a Vogel-Fulcher behavior. The relaxation processes are identified with specific molecular motions and activation energies are calculated in a linear approximation for comparison with literature data.

  9. Dependence of Brownian and Néel relaxation times on magnetic field strength

    International Nuclear Information System (INIS)

    Deissler, Robert J.; Wu, Yong; Martens, Michael A.

    2014-01-01

    Purpose: In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS) the relaxation time of the magnetization in response to externally applied magnetic fields is determined by the Brownian and Néel relaxation mechanisms. Here the authors investigate the dependence of the relaxation times on the magnetic field strength and the implications for MPI and MPS. Methods: The Fokker–Planck equation with Brownian relaxation and the Fokker–Planck equation with Néel relaxation are solved numerically for a time-varying externally applied magnetic field, including a step-function, a sinusoidally varying, and a linearly ramped magnetic field. For magnetic fields that are applied as a step function, an eigenvalue approach is used to directly calculate both the Brownian and Néel relaxation times for a range of magnetic field strengths. For Néel relaxation, the eigenvalue calculations are compared to Brown's high-barrier approximation formula. Results: The relaxation times due to the Brownian or Néel mechanisms depend on the magnitude of the applied magnetic field. In particular, the Néel relaxation time is sensitive to the magnetic field strength, and varies by many orders of magnitude for nanoparticle properties and magnetic field strengths relevant for MPI and MPS. Therefore, the well-known zero-field relaxation times underestimate the actual relaxation times and, in particular, can underestimate the Néel relaxation time by many orders of magnitude. When only Néel relaxation is present—if the particles are embedded in a solid for instance—the authors found that there can be a strong magnetization response to a sinusoidal driving field, even if the period is much less than the zero-field relaxation time. For a ferrofluid in which both Brownian and Néel relaxation are present, only one relaxation mechanism may dominate depending on the magnetic field strength, the driving frequency (or ramp time), and the phase of the magnetization relative to the

  10. Both oophorectomy and obesity impaired solely hippocampal-dependent memory via increased hippocampal dysfunction.

    Science.gov (United States)

    Mantor, Duangkamol; Pratchayasakul, Wasana; Minta, Wanitchaya; Sutham, Wissuta; Palee, Siripong; Sripetchwandee, Jirapas; Kerdphoo, Sasiwan; Jaiwongkum, Thidarat; Sriwichaiin, Sirawit; Krintratun, Warunsorn; Chattipakorn, Nipon; Chattipakorn, Siriporn C

    2018-04-17

    Our previous study demonstrated that obesity aggravated peripheral insulin resistance and brain dysfunction in the ovariectomized condition. Conversely, the effect of obesity followed by oophorectomy on brain oxidative stress, brain apoptosis, synaptic function and cognitive function, particularly in hippocampal-dependent and hippocampal-independent memory, has not been investigated. Our hypothesis was that oophorectomy aggravated metabolic impairment, brain dysfunction and cognitive impairment in obese rats. Thirty-two female rats were fed with either a normal diet (ND, n = 16) or a high-fat diet (HFD, n = 16) for a total of 20 weeks. At week 13, rats in each group were subdivided into sham and ovariectomized subgroups (n = 8/subgroup). At week 20, all rats were tested for hippocampal-dependent and hippocampal-independent memory by using Morris water maze test (MWM) and Novel objective recognition (NOR) tests, respectively. We found that the obese-insulin resistant condition occurred in sham-HFD-fed rats (HFS), ovariectomized-ND-fed rats (NDO), and ovariectomized-HFD-fed rats (HFO). Increased hippocampal oxidative stress level, increased hippocampal apoptosis, increased hippocampal synaptic dysfunction, decreased hippocampal estrogen level and impaired hippocampal-dependent memory were observed in HFS, NDO, and HFO rats. However, the hippocampal-independent memory, cortical estrogen levels, cortical ROS production, and cortical apoptosis showed no significant difference between groups. These findings suggested that oophorectomy and obesity exclusively impaired hippocampal-dependent memory, possibly via increased hippocampal dysfunction. Nonetheless, oophorectomy did not aggravate these deleterious effects under conditions of obesity. Copyright © 2017. Published by Elsevier Inc.

  11. Relaxation of Isolated Ventricular Cardiomyocytes by a Voltage-Dependent Process

    Science.gov (United States)

    Bridge, John H. B.; Spitzer, Kenneth W.; Ershler, Philip R.

    1988-08-01

    Cell contraction and relaxation were measured in single voltage-clamped guinea pig cardiomyocytes to investigate the contribution of sarcolemmal Na+-Ca2+ exchange to mechanical relaxation. Cells clamped from -80 to 0 millivolts displayed initial phasic and subsequent tonic contractions; caffeine reduced or abolished the phasic and enlarged the tonic contraction. The rate of relaxation from tonic contractions was steeply voltage-dependent and was significantly slowed in the absence of a sarcolemmal Na+ gradient. Tonic contractions elicited in the absence of a Na+ gradient promptly relaxed when external Na+ was applied, reflecting activation of Na+-Ca2+ exchange. It appears that a voltage-dependent Na+-Ca2+ exchange can rapidly mechanically relax mammalian heart muscle.

  12. Temperature-dependent structural relaxation in As{sub 40}Se{sub 60} glass

    Energy Technology Data Exchange (ETDEWEB)

    Golovchak, R., E-mail: roman_ya@yahoo.com [Lviv Sci. and Res. Institute of Materials of SRC ' Carat' , 202 Stryjska str., 79031 Lviv (Ukraine); Kozdras, A. [Opole University of Technology, 75, Ozimska str., Opole, PL-45370 (Poland); Academy of Management and Administration, 18 Niedzialkowski str., Opole, PL-45085 (Poland); Shpotyuk, O. [Jan Dlugosz University, 13/15, al. Armii Krajowej, 42201, Czestochowa (Poland); Gorecki, Cz. [Opole University of Technology, 75, Ozimska str., Opole, PL-45370 (Poland); Kovalskiy, A.; Jain, H. [Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States)

    2011-08-01

    The origin of structural relaxation in As{sub 40}Se{sub 60} glass at different annealing temperatures is studied by differential scanning calorimetry (DSC) and in situ extended X-ray absorption fine structure (EXAFS) methods. Strong physical aging effect, expressed through the increase of endothermic peak area in the vicinity of T{sub g}, is recorded by DSC technique at the annealing temperatures T{sub a}>90{sup o}C. EXAFS data show that the observed structural relaxation is not associated with significant changes in the short-range order of this glass. An explanation is proposed for this relaxation behavior assuming temperature-dependent constraints. -- Highlights: → In this study we report experimental evidence for temperature-dependent constraints theory. → Structural relaxation of As{sub 2}Se{sub 3} glass at higher annealing temperatures is studied by DSC technique. → Accompanied changes in the structure are monitored by in situ EXAFS measurements.

  13. Size dependence of 13C nuclear spin-lattice relaxation in micro- and nanodiamonds

    Science.gov (United States)

    Panich, A. M.; Sergeev, N. A.; Shames, A. I.; Osipov, V. Yu; Boudou, J.-P.; Goren, S. D.

    2015-02-01

    Size dependence of physical properties of nanodiamond particles is of crucial importance for various applications in which defect density and location as well as relaxation processes play a significant role. In this work, the impact of defects induced by milling of micron-sized synthetic diamonds was studied by magnetic resonance techniques as a function of the particle size. EPR and 13C NMR studies of highly purified commercial synthetic micro- and nanodiamonds were done for various fractions separated by sizes. Noticeable acceleration of 13C nuclear spin-lattice relaxation with decreasing particle size was found. We showed that this effect is caused by the contribution to relaxation coming from the surface paramagnetic centers induced by sample milling. The developed theory of the spin-lattice relaxation for such a case shows good compliance with the experiment.

  14. Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations

    International Nuclear Information System (INIS)

    Yang, Xu-Sheng; Wang, Yun-Jiang; Wang, Guo-Yong; Zhai, Hui-Ru; Dai, L.H.; Zhang, Tong-Yi

    2016-01-01

    In the present work, stress relaxation tests, high-resolution transmission electron microscopy (HRTEM), and molecular dynamics (MD) simulations were conducted on coarse-grained (cg), nanograined (ng), and nanotwinned (nt) copper at temperatures of 22 °C (RT), 30 °C, 40 °C, 50 °C, and 75 °C. The comprehensive investigations provide sufficient information for the building-up of a formula to describe the time, stress, and temperature-dependent deformation and clarify the relationship among the strain rate sensitivity parameter, stress exponent, and activation volume. The typically experimental curves of logarithmic plastic strain rate versus stress exhibited a three staged relaxation process from a linear high stress relaxation region to a subsequent nonlinear stress relaxation region and finally to a linear low stress relaxation region, which only showed-up at the test temperatures higher than 22 °C, 22 °C, and 30 °C, respectively, in the tested cg-, ng-, and nt-Cu specimens. The values of stress exponent, stress-independent activation energy, and activation volume were determined from the experimental data in the two linear regions. The determined activation parameters, HRTEM images, and MD simulations consistently suggest that dislocation-mediated plastic deformation is predominant in all tested cg-, ng-, and nt-Cu specimens in the initial linear high stress relaxation region at the five relaxation temperatures, whereas in the linear low stress relaxation region, the grain boundary (GB) diffusion-associated deformation is dominant in the ng- and cg-Cu specimens, while twin boundary (TB) migration, i.e., twinning and detwinning with parallel partial dislocations, governs the time, stress, and temperature-dependent deformation in the nt-Cu specimens.

  15. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    International Nuclear Information System (INIS)

    Xu, Yuan; Cardell, Lars-Olaf

    2014-01-01

    Introduction: Cigarette smoke induces local inflammation and airway hyperreactivity. In asthmatics, it worsens the symptoms and increases the risk for exacerbation. The present study investigates the effects of nicotine on airway relaxations in isolated murine tracheal segments. Methods: Segments were cultured for 24 h in the presence of vehicle, nicotine (10 μM) and/or dexamethasone (1 μM). Airway relaxations were assessed in myographs after pre-contraction with carbachol (1 μM). Kinin receptors, cyclooxygenase (COX) and inflammatory mediator expressions were assessed by real-time PCR and confocal-microscopy-based immunohistochemistry. Results: The organ culture procedure markedly increased bradykinin- (selective B 2 receptor agonist) and des-Arg 9 -bradykinin- (selective B 1 receptor agonist) induced relaxations, and slightly increased relaxation induced by isoprenaline, but not that induced by PGE 2 . The kinin receptor mediated relaxations were epithelium-, COX-2- and EP2-receptor-dependent and accompanied by drastically enhanced mRNA levels of kinin receptors, as well as inflammatory mediators MCP-1 and iNOS. Increase in COX-2 and mPGES-1 was verified both at mRNA and protein levels. Nicotine selectively suppressed the organ-culture-enhanced relaxations induced by des-Arg 9 -bradykinin and bradykinin, at the same time reducing mPGES-1 mRNA and protein expressions. α7-nicotinic acetylcholine receptor inhibitors α-bungarotoxin and MG624 both blocked the nicotine effects on kinin B 2 receptors, but not those on B 1 . Dexamethasone completely abolished kinin-induced relaxations. Conclusion: It is tempting to conclude that a local inflammatory process per se could have a bronchoprotective component by increasing COX-2 mediated airway relaxations and that nicotine could impede this safety mechanism. Dexamethasone further reduced airway inflammation together with relaxations. This might contribute to the steroid resistance seen in some patients with asthma

  16. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuan, E-mail: yuan.xu@ki.se; Cardell, Lars-Olaf

    2014-02-15

    Introduction: Cigarette smoke induces local inflammation and airway hyperreactivity. In asthmatics, it worsens the symptoms and increases the risk for exacerbation. The present study investigates the effects of nicotine on airway relaxations in isolated murine tracheal segments. Methods: Segments were cultured for 24 h in the presence of vehicle, nicotine (10 μM) and/or dexamethasone (1 μM). Airway relaxations were assessed in myographs after pre-contraction with carbachol (1 μM). Kinin receptors, cyclooxygenase (COX) and inflammatory mediator expressions were assessed by real-time PCR and confocal-microscopy-based immunohistochemistry. Results: The organ culture procedure markedly increased bradykinin- (selective B{sub 2} receptor agonist) and des-Arg{sup 9}-bradykinin- (selective B{sub 1} receptor agonist) induced relaxations, and slightly increased relaxation induced by isoprenaline, but not that induced by PGE{sub 2}. The kinin receptor mediated relaxations were epithelium-, COX-2- and EP2-receptor-dependent and accompanied by drastically enhanced mRNA levels of kinin receptors, as well as inflammatory mediators MCP-1 and iNOS. Increase in COX-2 and mPGES-1 was verified both at mRNA and protein levels. Nicotine selectively suppressed the organ-culture-enhanced relaxations induced by des-Arg{sup 9}-bradykinin and bradykinin, at the same time reducing mPGES-1 mRNA and protein expressions. α7-nicotinic acetylcholine receptor inhibitors α-bungarotoxin and MG624 both blocked the nicotine effects on kinin B{sub 2} receptors, but not those on B{sub 1}. Dexamethasone completely abolished kinin-induced relaxations. Conclusion: It is tempting to conclude that a local inflammatory process per se could have a bronchoprotective component by increasing COX-2 mediated airway relaxations and that nicotine could impede this safety mechanism. Dexamethasone further reduced airway inflammation together with relaxations. This might contribute to the steroid resistance seen in

  17. Melanopsin mediates light-dependent relaxation in blood vessels.

    Science.gov (United States)

    Sikka, Gautam; Hussmann, G Patrick; Pandey, Deepesh; Cao, Suyi; Hori, Daijiro; Park, Jong Taek; Steppan, Jochen; Kim, Jae Hyung; Barodka, Viachaslau; Myers, Allen C; Santhanam, Lakshmi; Nyhan, Daniel; Halushka, Marc K; Koehler, Raymond C; Snyder, Solomon H; Shimoda, Larissa A; Berkowitz, Dan E

    2014-12-16

    Melanopsin (opsin4; Opn4), a non-image-forming opsin, has been linked to a number of behavioral responses to light, including circadian photo-entrainment, light suppression of activity in nocturnal animals, and alertness in diurnal animals. We report a physiological role for Opn4 in regulating blood vessel function, particularly in the context of photorelaxation. Using PCR, we demonstrate that Opn4 (a classic G protein-coupled receptor) is expressed in blood vessels. Force-tension myography demonstrates that vessels from Opn4(-/-) mice fail to display photorelaxation, which is also inhibited by an Opn4-specific small-molecule inhibitor. The vasorelaxation is wavelength-specific, with a maximal response at ∼430-460 nm. Photorelaxation does not involve endothelial-, nitric oxide-, carbon monoxide-, or cytochrome p450-derived vasoactive prostanoid signaling but is associated with vascular hyperpolarization, as shown by intracellular membrane potential measurements. Signaling is both soluble guanylyl cyclase- and phosphodiesterase 6-dependent but protein kinase G-independent. β-Adrenergic receptor kinase 1 (βARK 1 or GRK2) mediates desensitization of photorelaxation, which is greatly reduced by GRK2 inhibitors. Blue light (455 nM) regulates tail artery vasoreactivity ex vivo and tail blood blood flow in vivo, supporting a potential physiological role for this signaling system. This endogenous opsin-mediated, light-activated molecular switch for vasorelaxation might be harnessed for therapy in diseases in which altered vasoreactivity is a significant pathophysiologic contributor.

  18. Load dependence of left ventricular contraction and relaxation. Effects of caffeine.

    Science.gov (United States)

    Leite-Moreira, A F; Correia-Pinto, J; Gillebert, T C

    1999-08-01

    Load dependence of left ventricular (LV) contraction and relaxation was investigated at baseline and after alteration of intracellular calcium handling by caffeine. Afterload was increased by aortic clamp occlusions (n = 281) in anesthetized open-chest dogs (n = 7). Control and first heartbeat after the intervention were considered for analysis. Caffeine (50 mg/kg, iv) had no inotropic effect. The systolic LV pressure (LVP), developed in response to aortic occlusion, decreased as ejection proceeded and this pressure generating capacity was not affected by caffeine. Late-systolic aortic occlusions induced premature onset and accelerated rate of initial LVP fall at baseline and similarly after caffeine. Graded diastolic aortic occlusions induced systolic LVP elevations of various magnitudes. Smaller LVP elevations prolonged ejection and accelerated LVP fall, while larger elevations had opposite effects. The transition from acceleration to deceleration was observed at 83.1 +/- 1.1% of peak isovolumetric LVP at baseline and at lower loads, at 77.6 +/- 1.2%, after caffeine (p caffeine (p dependence of relaxation, was also modified by caffeine. Caffeine affected LV relaxation without altering contractility. As a consequence contraction-relaxation coupling was modified by caffeine. These results might help to understand load dependence of relaxation in conditions where intracellular calcium handling is altered.

  19. Viscoelastic characterization of compacted pharmaceutical excipient materials by analysis of frequency-dependent mechanical relaxation processes

    Science.gov (United States)

    Welch, K.; Mousavi, S.; Lundberg, B.; Strømme, M.

    2005-09-01

    A newly developed method for determining the frequency-dependent complex Young's modulus was employed to analyze the mechanical response of compacted microcrystalline cellulose, sorbitol, ethyl cellulose and starch for frequencies up to 20 kHz. A Debye-like relaxation was observed in all the studied pharmaceutical excipient materials and a comparison with corresponding dielectric spectroscopy data was made. The location in frequency of the relaxation peak was shown to correlate to the measured tensile strength of the tablets, and the relaxation was interpreted as the vibrational response of the interparticle hydrogen and van der Waals bindings in the tablets. Further, the measured relaxation strength, holding information about the energy loss involved in the relaxation processes, showed that the weakest material in terms of tensile strength, starch, is the material among the four tested ones that is able to absorb the most energy within its structure when exposed to external perturbations inducing vibrations in the studied frequency range. The results indicate that mechanical relaxation analysis performed over relatively broad frequency ranges should be useful for predicting material properties of importance for the functionality of a material in applications such as, e.g., drug delivery, drug storage and handling, and also for clarifying the origin of hitherto unexplained molecular processes.

  20. The time-dependence of exchange-induced relaxation during modulated radio frequency pulses.

    Science.gov (United States)

    Sorce, Dennis J; Michaeli, Shalom; Garwood, Michael

    2006-03-01

    The problem of the relaxation of identical spins 1/2 induced by chemical exchange between spins with different chemical shifts in the presence of time-dependent RF irradiation (in the first rotating frame) is considered for the fast exchange regime. The solution for the time evolution under the chemical exchange Hamiltonian in the tilted doubly rotating frame (TDRF) is presented. Detailed derivation is specified to the case of a two-site chemical exchange system with complete randomization between jumps of the exchanging spins. The derived theory can be applied to describe the modulation of the chemical exchange relaxation rate constants when using a train of adiabatic pulses, such as the hyperbolic secant pulse. Theory presented is valid for quantification of the exchange-induced time-dependent rotating frame longitudinal T1rho,ex and transverse T2rho,ex relaxations in the fast chemical exchange regime.

  1. Endothelium-dependent relaxation induced by cathepsin G in porcine pulmonary arteries

    Science.gov (United States)

    Glusa, Erika; Adam, Christine

    2001-01-01

    Serine proteinases elicit profound cellular effects in various tissues mediated by activation of proteinase-activated receptors (PAR). In the present study, we investigated the vascular effects of cathepsin G, a serine proteinase that is present in the azurophil granules of leukocytes and is known to activate several cells that express PARs. In prostaglandin F2α (3 μM)-precontracted rings from porcine pulmonary arteries with intact endothelium, cathepsin G caused concentration-dependent relaxant responses (pEC50=9.64±0.12). The endothelium-dependent relaxant effect of cathepsin G could also be demonstrated in porcine coronary arteries (pEC50=9.23±0.07). In pulmonary arteries the cathepsin G-induced relaxation was inhibited after blockade of nitric oxide synthesis by L-NAME (200 μM) and was absent in endothelium-denuded vessels. Bradykinin- and cathepsin G-induced relaxant effects were associated with a 5.7 fold and 2.4 fold increase in the concentration of cyclic GMP, respectively. Compared with thrombin and trypsin, which also produced an endothelium-dependent relaxation in pulmonary arteries, cathepsin G was 2.5 and four times more potent, respectively. Cathepsin G caused only small homologous desensitization. In cathepsin G-challenged vessels, thrombin was still able to elicit a relaxant effect. The effects of cathepsin G were blocked by soybean trypsin inhibitor (IC50=0.043 μg ml−1), suggesting that proteolytic activity is essential for induction of relaxation. Recombinant acetyl-eglin C proved to be a potent inhibitor (IC50=0.14 μg ml−1) of the cathepsin G effect, whereas neither indomethacin (3 μM) nor the thrombin inhibitor hirudin (5 ATU ml−1) elicited any inhibitory activity. Due to their polyanionic structure defibrotide (IC50=0.11 μg ml−1), heparin (IC50=0.48 μg ml−1) and suramin (IC50=1.85 μg ml−1) diminished significantly the relaxation in response to the basic protein cathepsin G. In conclusion, like

  2. THE TRIAL OF FOUNDING THE DEPENDENCE BETWEEN THE SIZE OF HOOF SOLE AND BIOMETRIC MEASUREMENTS OF HUCUL HORSES

    Directory of Open Access Journals (Sweden)

    J. ŁUSZCZYŃSKI

    2007-10-01

    Full Text Available Hoofs are an important part of horse body and significantly influence its usability.According to irregular weight of horse limbs, fore-hoofs and hind-hoofs differ withthe shape, the angle of fore-wall inclination and size but they should be proportionalto horse body size. The objective of this study was the trial of founding the dependencebetween the size sole surface of fore- and hind-hoofs and biometric measurementsof Hucul horses. Contours of left fore- and hind-hoof were collected from 50Hucul horses from Gładyszów Stud (7 stallions and 43 mares. The contours werescanned in 1:1 scale and using the AutoCad computer program the surface and circumferenceof hoof sole were evaluated. At the same time the biometrical measurementswere taken from mentioned horses – height at withers, girth and cannon circumferences.In studied population the surface and circumference of fore-hoofs weresignificantly higher than of hind-hoofs. Biometrical measurements and indexescounted highly significantly and significantly affected the surface and circumferenceof Hucul horse hoofs. Horses with higher height at withers and higher girth capacitywere characterized by significantly higher surface and circumference of hind-hoofsthan in horses with lower height. Highly significantly higher sole surface and circumferenceof fore-hoofs was shown in horses with higher cannon circumference.

  3. Acrolein relaxes mouse isolated tracheal smooth muscle via a TRPA1-dependent mechanism.

    Science.gov (United States)

    Cheah, Esther Y; Burcham, Philip C; Mann, Tracy S; Henry, Peter J

    2014-05-01

    Airway sensory C-fibres express TRPA1 channels which have recently been identified as a key chemosensory receptor for acrolein, a toxic and highly prevalent component of smoke. TRPA1 likely plays an intermediary role in eliciting a range of effects induced by acrolein including cough and neurogenic inflammation. Currently, it is not known whether acrolein-induced activation of TRPA1 produces other airway effects including relaxation of mouse airway smooth muscle. The aims of this study were to examine the effects of acrolein on airway smooth muscle tone in mouse isolated trachea, and to characterise the cellular and molecular mechanisms underpinning the effects of acrolein. Isometric tension recording studies were conducted on mouse isolated tracheal segments to characterise acrolein-induced relaxation responses. Release of the relaxant PGE₂ was measured by EIA to examine its role in the response. Use of selective antagonists/inhibitors permitted pharmacological characterisation of the molecular and cellular mechanisms underlying this relaxation response. Acrolein induced dose-dependent relaxation responses in mouse isolated tracheal segments. Importantly, these relaxation responses were significantly inhibited by the TRPA1 antagonists AP-18 and HC-030031, an NK₁ receptor antagonist RP-67580, and the EP₂ receptor antagonist PF-04418948, whilst completely abolished by the non-selective COX inhibitor indomethacin. Acrolein also caused rapid PGE₂ release which was suppressed by HC-030031. In summary, acrolein induced a novel bronchodilator response in mouse airways. Pharmacologic studies indicate that acrolein-induced relaxation likely involves interplay between TRPA1-expressing airway sensory C-fibres, NK₁ receptor-expressing epithelial cells, and EP₂-receptor expressing airway smooth muscle cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Temperature dependence of 1H NMR relaxation time, T2, for intact and neoplastic plant tissues

    Science.gov (United States)

    Lewa, Czesław J.; Lewa, Maria

    Temperature dependences of the spin-spin proton relaxation time, T2, have been shown for normal and tumorous tissues collected from kalus culture Nicotiana tabacum and from the plant Kalanchoe daigremontiana. For neoplastic plant tissues, time T2 was increased compared to that for intact plants, a finding similar to that for animal and human tissues. The temperature dependences obtained were compared to analogous relations observed with animal tissues.

  5. Low-field one-dimensional and direction-dependent relaxation imaging of bovine articular cartilage

    Science.gov (United States)

    Rössler, Erik; Mattea, Carlos; Mollova, Ayret; Stapf, Siegfried

    2011-12-01

    The structure of articular cartilage is separated into three layers of differently oriented collagen fibers, which is accompanied by a gradient of increasing glycosaminoglycan (GAG) and decreasing water concentration from the top layer towards the bone interface. The combined effect of these structural variations results in a change of the longitudinal and transverse relaxation times as a function of the distance from the cartilage surface. In this paper, this dependence is investigated at a magnetic field strength of 0.27 T with a one-dimensional depth resolution of 50 μm on bovine hip and stifle joint articular cartilage. By employing this method, advantage is taken of the increasing contrast of the longitudinal relaxation rate found at lower magnetic field strengths. Furthermore, evidence for an orientational dependence of relaxation times with respect to an axis normal to the surface plane is given, an observation that has recently been reported using high-field MRI and that was explained by preferential orientations of collagen bundles in each of the three cartilage zones. In order to quantify the extent of a further contrast mechanism and to estimate spatially dependent glycosaminoglycan concentrations, the data are supplemented by proton relaxation times that were acquired in bovine articular cartilage that was soaked in a 0.8 mM aqueous Gd ++ solution.

  6. Arbutus unedo induces endothelium-dependent relaxation of the isolated rat aorta.

    Science.gov (United States)

    Ziyyat, Abderrahim; Mekhfi, Hassane; Bnouham, Mohamed; Tahri, Abdelhafid; Legssyer, Abdelkhaleq; Hoerter, Jacqueline; Fischmeister, Rodolphe

    2002-09-01

    Arbutus unedo L. (Ericaceae) is used in oriental Morocco to treat arterial hypertension. We studied its vasodilator effect and mechanisms of action in vitro. The root aqueous extract of Arbutus (0.25 mg/mL) produced a relaxation of noradrenaline-precontracted ring preparations of rat aorta with intact endothelium. Relaxation by Arbutus did not occur in specimens without endothelium and was inhibited by pretreatment with 100 microM N(G)-methyl-L-arginine (L-NMA), 10 microM methylene blue or 50 microM 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (ODQ) but not by 10 microM atropine. These results suggest that Arbutus produces an endothelium-dependent relaxation of the isolated rat aorta which may be mediated mainly by a stimulation of the endothelial nitric oxide synthase by mechanisms other than activation of muscarinic receptors. Copyright 2002 John Wiley & Sons, Ltd.

  7. Concentration dependence of fluorine impurity spin-lattice relaxation rate in bone mineral

    International Nuclear Information System (INIS)

    Code, R.F.; Armstrong, R.L.; Cheng, P.-T.

    1992-01-01

    The concentration dependence of the fluoride ion spin-lattice relaxation rate has been observed by nuclear magnetic resonance experiments on samples of defatted and dried bone. The 19 F spin-lattice relaxation rates increased linearly with bone fluoride concentration. Different results were obtained from trabecular than from cortical bone. For the same macroscopic fluoride content per gram of bone calcium, relaxation rate is significantly faster in cortical bone. Relaxation rates in cortical bone samples prepared from rats and dogs were apparently controlled by the same species-independent processes. For samples from beagle dogs, bulk fluoride concentrations measured by neutron activation analysis were 3.1±0.3 times greater in trabecular bone than in corresponding cortical bone. The beagle spin-lattice relaxation data suggest that microscopic fluoride concentrations in bone mineral were 1.8±0.4 times greater in trabecular bone than in cortical bone. It is concluded that accumulation of fluoride impurities in bone mineral is non-uniform. (author)

  8. Single-Molecule Imaging Reveals Topology Dependent Mutual Relaxation of Polymer Chains

    KAUST Repository

    Abadi, Maram

    2015-08-24

    The motion and relaxation of linear and cyclic polymers under entangled conditions are investigated by means of a newly developed single-molecule tracking technique, cumulative-area (CA) tracking. CA tracking enables simultaneous quantitative characterization of the diffusion mode, diffusion rate, and relaxation time that have been impossible with a widely used conventional single-molecule localization and tracking method, by analyzing cumulative areas occupied by the moving molecule. Using the novel approach, we investigate the motion and relaxation of entangled cyclic polymers, which have been an important but poorly understood question. Fluorescently labeled 42 kbp linear or cyclic tracer dsDNAs in concentrated solutions of unlabeled linear or cyclic DNAs are used as model systems. We show that CA tracking can explicitly distinguish topology-dependent diffusion mode, rate, and relaxation time, demonstrating that the method provides an invaluable tool for characterizing topological interaction between the entangled chains. We further demonstrate that the current models proposed for the entanglement between cyclic polymers which are based on cyclic chains moving through an array of fixed obstacles cannot correctly describe the motion of the cyclic chain under the entangled conditions. Our results rather suggest the mutual relaxation of the cyclic chains, which underscore the necessity of developing a new model to describe the motion of cyclic polymer under the entangled conditions based on the mutual interaction of the chains.

  9. Single-Molecule Imaging Reveals Topology Dependent Mutual Relaxation of Polymer Chains

    KAUST Repository

    Abadi, Maram; Serag, Maged F.; Habuchi, Satoshi

    2015-01-01

    The motion and relaxation of linear and cyclic polymers under entangled conditions are investigated by means of a newly developed single-molecule tracking technique, cumulative-area (CA) tracking. CA tracking enables simultaneous quantitative characterization of the diffusion mode, diffusion rate, and relaxation time that have been impossible with a widely used conventional single-molecule localization and tracking method, by analyzing cumulative areas occupied by the moving molecule. Using the novel approach, we investigate the motion and relaxation of entangled cyclic polymers, which have been an important but poorly understood question. Fluorescently labeled 42 kbp linear or cyclic tracer dsDNAs in concentrated solutions of unlabeled linear or cyclic DNAs are used as model systems. We show that CA tracking can explicitly distinguish topology-dependent diffusion mode, rate, and relaxation time, demonstrating that the method provides an invaluable tool for characterizing topological interaction between the entangled chains. We further demonstrate that the current models proposed for the entanglement between cyclic polymers which are based on cyclic chains moving through an array of fixed obstacles cannot correctly describe the motion of the cyclic chain under the entangled conditions. Our results rather suggest the mutual relaxation of the cyclic chains, which underscore the necessity of developing a new model to describe the motion of cyclic polymer under the entangled conditions based on the mutual interaction of the chains.

  10. Maternal smoking and impaired endothelium-dependent nitric oxide-mediated relaxation of uterine small arteries in vitro

    DEFF Research Database (Denmark)

    Andersen, Malene R; Uldbjerg, Niels; Stender, Steen

    2011-01-01

    This study aimed to investigate the endothelium-dependent relaxation of uterine small arteries from pregnant nonsmokers, smokers, and ex-smokers who stopped smoking early in pregnancy.......This study aimed to investigate the endothelium-dependent relaxation of uterine small arteries from pregnant nonsmokers, smokers, and ex-smokers who stopped smoking early in pregnancy....

  11. Characterization of relaxation processes in interacting vortex matter through a time-dependent correlation length

    International Nuclear Information System (INIS)

    Pleimling, Michel; Täuber, Uwe C

    2015-01-01

    Vortex lines in type-II superconductors display complicated relaxation processes due to the intricate competition between their mutual repulsive interactions and pinning to attractive point or extended defects. We perform extensive Monte Carlo simulations for an interacting elastic line model with either point-like or columnar pinning centers. From measurements of the space- and time-dependent height-height correlation function for lateral flux line fluctuations, we extract a characteristic correlation length that we use to investigate different non-equilibrium relaxation regimes. The specific time dependence of this correlation length for different disorder configurations displays characteristic features that provide a novel diagnostic tool to distinguish between point-like pinning centers and extended columnar defects. (paper)

  12. Resveratrol Protects and Restores Endothelium-Dependent Relaxation in Hypercholesterolemic Rabbit Corpus Cavernosum.

    Science.gov (United States)

    Murat, Nergiz; Korhan, Peyda; Kizer, Onur; Evcim, Sinem; Kefi, Aykut; Demir, Ömer; Gidener, Sedef; Atabey, Neşe; Esen, Ahmet Adil

    2016-01-01

    Oxidative stress dependent-decrease in nitric oxide (NO) bioavailability plays an integral role in hypercholesterolemia-induced erectile dysfunction (ED). Resveratrol has been demonstrated to exert beneficial effects against oxidative stress and improve NO bioavailability. The protective and restorative potentials of resveratrol on endothelium-dependent relaxations were evaluated in hypercholesterolemic rabbit corpus cavernosum (CC). Hypercholesterolemia was induced by administering 2% cholesterol diet (CD) (w/w) to the rabbits for 6 weeks. Two different protocols were applied to test the effects of resveratrol on hypercholesterolemia-induced ED. In Protocol-1 (P1), resveratrol was administrated to the rabbits simultaneously with CD in order to evaluate the protective effect, and for Protocol-2 (P2), resveratrol was administrated for 6 weeks after termination of CD in order to evaluate the restorative effect. Endothelium-dependent relaxations of CC were evaluated by using organ bath studies. In order to elucidate the possible molecular mechanisms, we measured endothelial NO synthase (eNOS) and phosphovasodilator-stimulated phosphoprotein (VASP) expressions and activations, NADPH oxidase, superoxide dismutase (SOD), and catalase (CAT) and glutathione peroxidase (GPx) activity in cavernosal tissues obtained at the end of the study. Resveratrol showed an improvement in the endothelium-dependent relaxation responses in vitro. We demonstrated significantly increased activatory-phosphorylation (p[S1177]-eNOS) and activated phosphovasodilator-stimulated phosphoprotein (phospho-VASP) levels, but reduced phosphorylation (p[T495]-eNOS) of eNOS and NADPH oxidase activity in the resveratrol-administered HC animals compared with hypercholesterolemic control rabbits in the P1. In the P2, resveratrol exhibited an improvement in endothelium-dependent relaxation responses and more pronounced effects on eNOS activation. Resveratrol administration, either simultaneously with HC diet

  13. Excess L-arginine restores endothelium-dependent relaxation impaired by monocrotaline pyrrole

    International Nuclear Information System (INIS)

    Cheng Wei; Oike, Masahiro; Hirakawa, Masakazu; Ohnaka, Keizo; Koyama, Tetsuya; Ito, Yushi

    2005-01-01

    The pyrrolizidine alkaloid plant toxin monocrotaline pyrrole (MCTP) causes pulmonary hypertension in experimental animals. The present study aimed to examine the effects of MCTP on the endothelium-dependent relaxation. We constructed an in vitro disease model of pulmonary hypertension by overlaying MCTP-treated bovine pulmonary artery endothelial cells (CPAEs) onto pulmonary artery smooth muscle cell-embedded collagen gel lattice. Acetylcholine (Ach) induced a relaxation of the control CPAEs-overlaid gels that were pre-contracted with noradrenaline, and the relaxation was inhibited by L-NAME, an inhibitor of NO synthase (NOS). In contrast, when MCTP-treated CPAEs were overlaid, the pre-contracted gels did not show a relaxation in response to Ach in the presence of 0.5 mM L-arginine. Expression of endothelial NOS protein, Ach-induced Ca 2+ transients and cellular uptake of L-[ 3 H]arginine were significantly smaller in MCTP-treated CPAEs than in control cells, indicating that these changes were responsible for the impaired NO production in MCTP-treated CPAEs. Since cellular uptake of L-[ 3 H]arginine linearly increased according to its extracellular concentration, we hypothesized that the excess concentration of extracellular L-arginine might restore NO production in MCTP-treated CPAEs. As expected, in the presence of 10 mM L-arginine, Ach showed a relaxation of the MCTP-treated CPAEs-overlaid gels. These results indicate that the impaired NO production in damaged endothelial cells can be reversed by supplying excess L-arginine

  14. Temperature dependence of relaxation times in proton components of fatty acids

    International Nuclear Information System (INIS)

    Kuroda, Kagayaki; Iwabuchi, Taku; Saito, Kensuke; Obara, Makoto; Honda, Masatoshi; Imai, Yutaka

    2011-01-01

    We examined the temperature dependence of relaxation times in proton components of fatty acids in various samples in vitro at 11 tesla as a standard calibration data for quantitative temperature imaging of fat. The spin-lattice relaxation time, T 1 , of both the methylene (CH 2 ) chain and terminal methyl (CH 3 ) was linearly related to temperature (r>0.98, P 2 signal for calibration and observed the signal with 18% of CH 3 to estimate temperature. These findings suggested that separating the fatty acid components would significantly improve accuracy in quantitative thermometry for fat. Use of the T 1 of CH 2 seems promising in terms of reliability and reproducibility in measuring temperature of fat. (author)

  15. Relaxivity of blood pool contrast agent depends on the host tissue as suggested by semianalytical simulations

    DEFF Research Database (Denmark)

    Jensen, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    Concentration of MRI contrast agents (CA) is commonly determined indirectly using their relaxation effect. In quantitative perfusion studies, the change in the relaxation following a bolus passage is converted into concentrations assuming identical relaxivities for tissue and blood. Simulations...

  16. Deducting the temperature dependence of the structural relaxation time in equilibrium far below the nominal Tg by aging the decoupled conductivity relaxation to equilibrium.

    Science.gov (United States)

    Wojnarowska, Z; Ngai, K L; Paluch, M

    2014-05-07

    Using broadband dielectric spectroscopy we investigate the changes in the conductivity relaxation times τσ observed during the physical aging of the protic ionic conductor carvedilol dihydrogen phosphate (CP). Due to the large decoupling of ion diffusion from host molecule reorientation, the ion conductivity relaxation time τσ(Tage,tage) can be directly measured at temperatures Tage below Tg for exceedingly long aging times tage till τσ(Tage,tage) has reached the equilibrium value τσ(eq)(Tage). The dependence of τσ(Tage,tage) on tage is well described by the stretched exponential function, τσ(Tage, tage) = Aexp[-((tage)/(τage(Tage)))(β)] + τσ(eq)(Tage), where β is a constant and τage(Tage) can be taken as the structural α-relaxation time of the equilibrium liquid at T = Tage. The value of τσ(eq)(Tage) obtained after 63 days long annealing of CP, deviates from the Vogel-Fulcher-Tammann-Hesse (VFTHσ) dependence of τσ(T) determined from data taken above Tg and extrapolated down to Tage. Concurrently, τage(Tage) also deviates from the Vogel-Fulcher-Tammann-Hesse (VFTHα) dependence. The results help to answer the longstanding question of whether the VFTH dependence of τσ(T) as well as the structural α-relaxation time τα(T) holds or not in the equilibrium liquid state far below Tg.

  17. The laser second threshold: Its exact analytical dependence on detuning and relaxation rates

    International Nuclear Information System (INIS)

    Bakasov, A.A.; Abraham, N.B.

    1992-11-01

    An exact analysis has been carried out for general analytical expressions for the second threshold of a single-mode homogeneously broadened laser and for the initial pulsation frequency at the second threshold for arbitrary physical values of the relaxation rates, and at arbitrary detuning between the cavity frequency and the atomic resonance frequency. These expressions also give correspondingly exact forms for asymptotic cases that have previously studied with some approximations. Earlier approximate results are partly confirmed and partly improved by these more general expressions. The physical status of various expressions and approximations is re-considered and specified more clearly, including an analysis of which reasonably can be attained in lasers or masers. A general analytical proof is given that for larger detuning of the laser cavity from resonance a higher value of the laser excitation is required to destabilize the steady state solution (the second threshold). We also present results for the minimum value of the second threshold at fixed detuning as a function of the other parameters of the system and on the dependence of the ratio of the second threshold to the first threshold as a function of detuning. Minima of the second threshold and of the threshold ratio occur only if the population relaxation rate is equal to zero. The minima of the threshold ratio are shown to be bounded from above as well as from below (as functions of the relaxation rates, so long as the second threshold exists). The upper bound on the threshold ratio is equal to 17. The variation of the second threshold in the semi-infinite parameter space of the decay rates is shown at various detunings in plots with a finite domain by normalizing the material relaxation rates to the cavity decay rate. (author). 53 refs, 22 figs, 3 tabs

  18. Temperature dependence of the NMR spin-lattice relaxation rate for spin-1/2 chains

    Science.gov (United States)

    Coira, E.; Barmettler, P.; Giamarchi, T.; Kollath, C.

    2016-10-01

    We use recent developments in the framework of a time-dependent matrix product state method to compute the nuclear magnetic resonance relaxation rate 1 /T1 for spin-1/2 chains under magnetic field and for different Hamiltonians (XXX, XXZ, isotropically dimerized). We compute numerically the temperature dependence of the 1 /T1 . We consider both gapped and gapless phases, and also the proximity of quantum critical points. At temperatures much lower than the typical exchange energy scale, our results are in excellent agreement with analytical results, such as the ones derived from the Tomonaga-Luttinger liquid (TLL) theory and bosonization, which are valid in this regime. We also cover the regime for which the temperature T is comparable to the exchange coupling. In this case analytical theories are not appropriate, but this regime is relevant for various new compounds with exchange couplings in the range of tens of Kelvin. For the gapped phases, either the fully polarized phase for spin chains or the low-magnetic-field phase for the dimerized systems, we find an exponential decrease in Δ /(kBT ) of the relaxation time and can compute the gap Δ . Close to the quantum critical point our results are in good agreement with the scaling behavior based on the existence of free excitations.

  19. Effect of lithium on endothelium-dependent and neurogenic relaxation of rat corpus cavernosum: role of nitric oxide pathway.

    Science.gov (United States)

    Sadeghipour, Hamed; Ghasemi, Mehdi; Ebrahimi, Farzad; Dehpour, Ahmad Reza

    2007-02-01

    Some studies have reported erectile dysfunction in patients receiving lithium through a mechanism that has not yet been defined. The aim of the present study was to verify the effect of acute lithium administration on the nonadrenergic noncholinergic (NANC)- and endothelium-mediated relaxation of rat isolated corpus cavernosum. The isolated rat corporeal strips were precontracted with phenylephrine hydrochloride (7.5 microM) and electrical field stimulation (EFS) was applied at different frequencies (2, 5, 10, and 15 Hz) to obtain NANC-mediated relaxation or relaxed by adding cumulative doses of acetylcholine (10nM-1mM) to obtain endothelium-dependent relaxation in the presence or absence of lithium (0.3, 0.5, 1, and 5mM). Also, effects of combining lithium (0.3mM) with 30 nM and 0.1 nM L-NAME (an NO synthase inhibitor) on NANC- and acetylcholine-mediated relaxation was investigated, respectively. Moreover, effects of combining lithium (1mM) with 0.1mM and 10 microM L-arginine (a precursor of NO) on NANC- and endothelium-mediated relaxation was assessed, respectively. Also, the effect of lithium (1mM) on relaxation to sodium nitroprusside (SNP; 1nM-1mM), an NO donor, was investigated. The NANC-mediated relaxation was significantly (Pacetylcholine in a concentration-dependent manner. Combination of lithium (0.3mM) with 30 and 0.1 nM L-NAME, which separately had a minimum effect on NANC- and endothelium-mediated relaxation, significantly (Pacetylcholine and EFS, it improved the inhibition by lithium (1mM) of relaxant responses to acetylcholine and EFS, respectively. Also, SNP produced similar concentration-dependent relaxations from both groups. Our experiments indicated that lithium likely by interfering with NO pathway in both endothelium and nitrergic nerve can result in impairment of both the endothelium- and NANC-mediated relaxation of rat corpus cavernosum.

  20. Relaxation behavior and dose dependence of radiation induced radicals in irradiated mango

    International Nuclear Information System (INIS)

    Kameya, Hiromi; Kakita, Daisuke; Kaimori, Yoshihiko; Ukai, Mitsuko; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Shimoyama, Yuhei

    2010-01-01

    Mangoes are imported to Japan after treated with hot water. Recently, irradiated mangoes imported to U. S. are widely used. This paper reports on the ESR method for analyzing the radiation induced radicals of irradiated mangoes. Upon the γ ray irradiation, a strong single peak in the flesh and skin of mangoes was observed at g=2.004. This singlet peak may be attributed to organic free radicals. The ESR spectra of the flesh and skin of mangoes showed the radiation induced radicals due to cellulose by irradiation over 12 kGy. The relaxation times (T 1 and T 2 ) of the singlet signal were calculated. T 2 showed dose response according to increasing the irradiation dose levels, while T 1 was almost constant. The value of (T 1 T 2 ) 1/2 showed the dependence of irradiation dose level. (author)

  1. Gou-teng (from Uncaria rhynchophylla Miquel)-induced endothelium-dependent and -independent relaxations in the isolated rat aorta.

    Science.gov (United States)

    Kuramochi, T; Chu, J; Suga, T

    1994-01-01

    Gou-teng is a drug used for treatment of hypertension in Chinese medicine. Its antihypertensive action has been previously confirmed in the spontaneously hypertensive rat (SHR). Here, its vasorelaxing effect and the mechanisms of actions were studied in vitro. Gou-teng extract (GTE) relaxed the norepinephrine (NE)-precontracted aortic ring preparations isolated from Wistar Kyoto rats (WKY) with and without intact endothelium; the latter was significantly less sensitive than the former. The GTE-induced endothelium-dependent relaxation was significantly inhibited by NG-monomethyl-L-arginine (NMMA) in a dose-dependent manner while indomethacin did not affect the relaxation. Atropine inhibited the acetylcholine (ACh)-induced endothelium-dependent relaxation but did not the GTE-induced one. Furthermore, once GTE was applied, the following NE-induced contraction was significantly reduced even after repeated washout. NMMA effectively reduced and rather reversed this residual effect of GTE. From these results, it is concluded that GTE relaxes the NE-precontracted rat aorta through endothelium-dependent and, to lesser extent, -independent mechanisms. The endothelium-dependent component would be mediated by EDRF/NO pathway in which the muscarinic cholinoceptors were not involved. Thus, GTE appears to be a potent and long-lasting vasodilator mainly through EDRF/NO release.

  2. Electric field dependence of the spin relaxation anisotropy in (111) GaAs/AlGaAs quantum wells

    International Nuclear Information System (INIS)

    Balocchi, A; Amand, T; Renucci, P; Duong, Q H; Marie, X; Wang, G; Liu, B L

    2013-01-01

    Time-resolved optical spectroscopy experiments in (111)-oriented GaAs/AlGaAs quantum wells (QWs) show a strong electric field dependence of the conduction electron spin relaxation anisotropy. This results from the interplay between the Dresselhaus and Rashba spin splitting in this system with C 3v symmetry. By varying the electric field applied perpendicular to the QW plane from 20 to 50 kV cm −1 the anisotropy of the spin relaxation time parallel (τ s ∥ ) and perpendicular (τ s ⊥ ) to the growth axis can be first canceled and eventually inversed with respect to the one usually observed in III–V zinc-blende QW (τ s ⊥ = 2τ s ∥ ). This dependence stems from the nonlinear contributions of the k-dependent conduction band spin splitting terms which begin to play the dominant spin relaxing role while the linear Dresselhaus terms are compensated by the Rashba ones through the applied bias. A spin density matrix model for the conduction band spin splitting including both linear and cubic terms of the Dresselhaus Hamiltonian is used which allows a quantitative description of the measured electric field dependence of the spin relaxation anisotropy. The existence of an isotropic point where the spin relaxation tensor reduces to a scalar is predicted and confirmed experimentally. The spin splitting compensation electric field and collision processes type in the QW can be likewise directly extracted from the model without complementary measurements. (paper)

  3. Effect of prolonged incubation with copper on endothelium-dependent relaxation in rat isolated aorta

    Science.gov (United States)

    Chiarugi, Alberto; Pitari, Giovanni Mario; Costa, Rosa; Ferrante, Margherita; Villari, Loredana; Amico-Roxas, Matilde; Godfraind, Théophile; Bianchi, Alfredo; Salomone, Salvatore

    2002-01-01

    We investigated the effects of prolonged exposure to copper (Cu2+) on vascular functioning of isolated rat aorta. Aortic rings were exposed to CuSO4 (3–24 h) in Dulbecco's modified Eagle medium with or without 10% foetal bovine serum (FBS) and then challenged with vasoconstrictors or vasodilators in the absence of Cu2+. Exposure to 2 μM Cu2+ in the absence of FBS did not modify the response to phenylephrine (PE) or acetylcholine (ACh) in aortic rings incubated for 24 h. Identical exposure in the presence of FBS increased the contractile response to 1 μM PE by 30% (P<0.05) and impaired the relaxant response to 3 μM ACh or 1 μM A23187 (ACh, from 65.7±7.1 to 6.2±1.1%, n=8; A23187, from 74.6±8.2 to 12.0±0.8%, n=6; P<0.01 for both). Cu2+ exposure did not affect the relaxant response to NO-donors. Impairment of vasorelaxation appeared 3 h after incubation with 2 μM Cu2+ and required 12 h to attain a steady state. Vasorelaxation to ACh was partially restored by 1 mM tiron (intracellular scavenger of superoxide ions; maximum relaxation 34.2±6.4%, n=10, P<0.01 vs Cu2+ alone), whereas catalase, superoxide dismutase or cycloheximide were ineffective. Twenty-four hour-exposure to 2 μM Cu2+ did not affect endothelium integrity or eNOS expression, and increased the Cu content in arterial rings from 6.8±1.1 to 18.9±2.9 ng mg−1 wet weight, n=8; P<0.01. Our results show that, in the presence of FBS, prolonged exposure to submicromolar concentrations of Cu2+ impaired endothelium-dependent vasorelaxation in aortic rings, probably through an intracellular generation of superoxide ions. PMID:12163352

  4. Relaxation oscillations induced by amplitude-dependent frequency in dissipative trapped electron mode turbulence

    International Nuclear Information System (INIS)

    Terry, P.W.; Ware, A.S.; Newman, D.E.

    1994-01-01

    A nonlinear frequency shift in dissipative trapped electron mode turbulence is shown to give rise to a relaxation oscillation in the saturated power density spectrum. A simple non-Markovian closure for the coupled evolution of ion momentum and electron density response is developed to describe the oscillations. From solutions of a nonlinear oscillator model based on the closure, it is found that the oscillation is driven by the growth rate, as modified by the amplitude-dependent frequency shift, with inertia provided by the memory of the growth rate of prior amplitudes. This memory arises from time-history integrals common to statistical closures. The memory associated with a finite time of energy transfer between coupled spectrum components does not sustain the oscillation in the simple model. Solutions of the model agree qualitatively with the time-dependent numerical solutions of the original dissipative trapped electron model, yielding oscillations with the proper phase relationship between the fluctuation energy and the frequency shift, the proper evolution of the wave number spectrum shape and particle flux, and a realistic period

  5. Preservation of endothelium-dependent relaxation in atherosclerotic mice with endothelium-restricted endothelin-1 overexpression.

    Science.gov (United States)

    Mian, Muhammad Oneeb Rehman; Idris-Khodja, Noureddine; Li, Melissa W; Leibowitz, Avshalom; Paradis, Pierre; Rautureau, Yohann; Schiffrin, Ernesto L

    2013-10-01

    In human atherosclerosis, which is associated with elevated plasma and coronary endothelin (ET)-1 levels, ETA receptor antagonists improve coronary endothelial function. Mice overexpressing ET-1 specifically in the endothelium (eET-1) crossed with atherosclerosis-prone apolipoprotein E knockout mice (Apoe(-/-)) exhibit exaggerated high-fat diet (HFD)-induced atherosclerosis. Since endothelial dysfunction often precedes atherosclerosis development, we hypothesized that mice overexpressing endothelial ET-1 on a genetic background deficient in apolipoprotein E (eET-1/Apoe(-/-)) would have severe endothelial dysfunction. To test this hypothesis, we investigated endothelium-dependent relaxation (EDR) to acetylcholine in eET-1/Apoe(-/-) mice. EDR in mesenteric resistance arteries from 8- and 16-week-old mice fed a normal diet or HFD was improved in eET-1/Apoe(-/-) compared with Apoe(-/-) mice. Nitric oxide synthase (NOS) inhibition abolished EDR in Apoe(-/-). EDR in eET-1/Apoe(-/-) mice was resistant to NOS inhibition irrespective of age or diet. Inhibition of cyclooxygenase, the cytochrome P450 pathway, and endothelium-dependent hyperpolarization (EDH) resulted in little or no inhibition of EDR in eET-1/Apoe(-/-) compared with wild-type (WT) mice. In eET-1/Apoe(-/-) mice, blocking of EDH or soluble guanylate cyclase (sGC), in addition to NOS inhibition, decreased EDR by 36 and 30%, respectively. The activation of 4-aminopyridine-sensitive voltage-dependent potassium channels (Kv) during EDR was increased in eET-1/Apoe(-/-) compared with WT mice. We conclude that increasing eET-1 in mice that develop atherosclerosis results in decreased mutual dependence of endothelial signaling pathways responsible for EDR, and that NOS-independent activation of sGC and increased activation of Kv are responsible for enhanced EDR in this model of atherosclerosis associated with elevated endothelial and circulating ET-1.

  6. Pharmacology of Endothelium-Dependent and Independent Relaxation of Rabbit Aorta

    DEFF Research Database (Denmark)

    Larsen, Kirsten Vendelbo

    2001-01-01

    The purpose of this study was to investigate several aspects of the acetylcholine-evoked relaxation of blood vessels: methodologic aspects; gender; storage; elevated glucose incubation; the signal transduction pathway; and effects of prolonged exposure. Furthermore, the relaxing effect of some ad...

  7. Safety factor profile dependence of turbulent structure formation in relevant to internal transport barrier relaxation

    International Nuclear Information System (INIS)

    Tokunaga, S.; Yagi, M.; Itoh, S.-I.; Itoh, K.

    2009-01-01

    Full text: It is widely understood that the improved confinement mode with transport barrier is necessary to achieve the self-ignition condition in ITER. The negative magnetic shear, mean ExB flow shear, and zonal flow are considered to play important roles for ITB formation. In our previous study, it is found that the non-linear interaction between the meso-scale modes produces non-local energy transfer to the off-resonant mode in the vicinity of q min surface and brings global relaxation of the temperature profile involving ITB collapse. Experimental studies indicate that a relationship exists between the ITB formation and safety factor q-profile, with a reversed magnetic shear (RS) configuration. Transitional ITB events occur on the low-order rational resonant surface. The ITB shape and location depend on the q-profile and q min position. These observations indicate that the q-profile might play an essential role in determining the turbulent structure. In this study, the effect of safety factor profile on the ion temperature gradient driven drift wave (ITG) turbulence is investigated using a global non-linear simulation code based on the gyro-fluid model. A heat source and toroidal momentum source are introduced. Dependence of safety factor profiles on ITB formation and its stability is examined to clarify the influence of the radial distribution of the rational surfaces and the q min value. It is found that the nonlinearly excited meso-scale mode in the vicinity of q min depends on the value of q min . A detailed analysis of the structure selection rule is in progress. (author)

  8. Ionic relaxation in PEO/PVDF-HFP-LiClO4 blend polymer electrolytes: dependence on salt concentration

    Science.gov (United States)

    Das, S.; Ghosh, A.

    2016-06-01

    In this paper, we have studied the effect of LiClO4 salt concentration on the ionic conduction and relaxation in poly ethylene oxide (PEO) and poly (vinylidene fluoride hexafluoropropylene) (PVDF-HFP) blend polymer electrolytes, in which the molar ratio of ethylene oxide segments to lithium ions (R  =  EO: Li) has been varied between 3 and 35. We have observed two phases in the samples containing low salt concentrations (R  >  9) and single phase in the samples containing high salt concentrations (R  ⩽  9). The scanning electron microscopic images indicate that there exists no phase separation in the blend polymer electrolytes. The temperature dependence of the ionic conductivity shows two slopes corresponding to high and low temperatures and follows Arrhenius relation for the samples containing low salt concentrations (R  >  9). The conductivity relaxation as well as the structural relaxation has been clearly observed at around 104 Hz and 106 Hz for these concentrations of the blended electrolytes. However, a single conductivity relaxation peak has been observed for the compositions with R  ⩽  9. The scaling of the conductivity spectra shows that the relaxation mechanism is independent of temperature, but depends on salt concentration.

  9. Angiotensin-(1-7) augments endothelium-dependent relaxations of porcine coronary arteries to bradykinin by inhibiting angiotensin-converting enzyme 1.

    Science.gov (United States)

    Raffai, Gábor; Khang, Gilson; Vanhoutte, Paul M

    2014-05-01

    Angiotensin-converting enzyme 2 (ACE2) converts angiotensin II to angiotensin-(1-7) that activates Mas receptors, inhibits ACE1, and modulates bradykinin receptor sensitivity. This in vitro study compared the direct and indirect effects of angiotensin-(1-7), the ACE1 inhibitor captopril, and diminazene aceturate (DIZE) an alleged ACE2 activator in rings of porcine coronary arteries, by measuring changes of isometric tension. Angiotensin-(1-7), captopril, and DIZE did not cause significant changes in tension before or after desensitization of bradykinin receptors in preparations contracted with U46619. Bradykinin caused concentration-dependent and endothelium-dependent relaxations that were not affected by DIZE but were potentiated to a similar extent by angiotensin-(1-7) and captopril, given alone or in combination. Bradykinin responses potentiated by angiotensin-(1-7) and captopril were not affected by the BK1 antagonist SSR240612 and remained augmented in the presence of either N-nitro-L-arginine methyl ester hydrochloride plus indomethacin or TRAM-34 plus UCL-1684. ACE2 was identified in the coronary endothelium by immunofluorescence, but its basal activity was not influenced by DIZE. These results suggest that in coronary arteries, angiotensin-(1-7) and captopril both improves NO bioavailability and enhances endothelium-dependent hyperpolarization to bradykinin solely by ACE1 inhibition. Endothelial ACE2 activity cannot be increased by DIZE to produce local adequate amounts of angiotensin-(1-7) to influence vascular tone.

  10. Temperature dependent dielectric relaxation and ac-conductivity of alkali niobate ceramics studied by impedance spectroscopy

    Science.gov (United States)

    Yadav, Abhinav; Mantry, Snigdha Paramita; Fahad, Mohd.; Sarun, P. M.

    2018-05-01

    Sodium niobate (NaNbO3) ceramics is prepared by conventional solid state reaction method at sintering temperature 1150 °C for 4 h. The structural information of the material has been investigated by X-ray diffraction (XRD) and Field emission scanning electron microscopy (FE-SEM). The XRD analysis of NaNbO3 ceramics shows an orthorhombic structure. The FE-SEM micrograph of NaNbO3 ceramics exhibit grains with grain sizes ranging between 1 μm to 5 μm. The surface coverage and average grain size of NaNbO3 ceramics are found to be 97.6 % and 2.5 μm, respectively. Frequency dependent electrical properties of NaNbO3 is investigated from room temperature to 500 °C in wide frequency range (100 Hz-5 MHz). Dielectric constant, ac-conductivity, impedance, modulus and Nyquist analysis are performed. The observed dielectric constant (1 kHz) at transition temperature (400 °C) are 975. From conductivity analysis, the estimated activation energy of NaNbO3 ceramics is 0.58 eV at 10 kHz. The result of Nyquist plot shows that the electrical behavior of NaNbO3 ceramics is contributed by grain and grain boundary responses. The impedance and modulus spectrum asserts that the negative temperature coefficient of resistance (NTCR) behavior and non-Debye type relaxation in NaNbO3.

  11. Relaxivity of blood pool contrast agent depends on the host tissue as suggested by semianalytical simulations

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij

    Concentration of magnetic resonance imaging (MRI) contrast agents (CA) cannot be measured directly and is commonly determined indirectly using their relaxation effect. This requires knowledge of the relaxivity of the used CA. Quantitative perfusion studies involve measurement of CA concentration...... studies (3,4) as demonstrated in (5). It was previously found (6) that the perfusion measurements using dynamic susceptibility contrast inherently overestimate cerebral blood flow and volume. In view of the present result, this is attributed to the significant difference in the relaxivity of the CA...

  12. Endothelium-dependent relaxation and angiotensin II sensitivity in experimental preeclampsia.

    Directory of Open Access Journals (Sweden)

    Anne Marijn van der Graaf

    Full Text Available OBJECTIVE: We investigated endothelial dysfunction and the role of angiotensin (Ang-II type I (AT1-R and type II (AT2-R receptor in the changes in the Ang-II sensitivity in experimental preeclampsia in the rat. METHODS: Aortic rings were isolated from low dose lipopolysaccharide (LPS infused pregnant rats (experimental preeclampsia; n=9, saline-infused pregnant rats (n=8, and saline (n=8 and LPS (n=8 infused non-pregnant rats. Endothelium-dependent acetylcholine-mediated relaxation was studied in phenylephrine-preconstricted aortic rings in the presence of vehicle, N(G-nitro-L-arginine methyl ester and/or indomethacin. To evaluate the role for AT1-R and AT2-R in Ang-II sensitivity, full concentration response curves were obtained for Ang-II in the presence of losartan or PD123319. mRNA expression of the AT1-R and AT2-R, eNOS and iNOS, COX1 and COX2 in aorta were evaluated using real-time RT-PCR. RESULTS: The role of vasodilator prostaglandins in the aorta was increased and the role of endothelium-derived hyperpolarizing factor and response of the AT1-R and AT2-R to Ang-II was decreased in pregnant saline infused rats as compared with non-pregnant rats. These changes were not observed during preeclampsia. CONCLUSION: Pregnancy induced adaptations in endothelial function, which were not observed in the rat model for preeclampsia. This role of lack of pregnancy induced endothelial adaptation in the pathophysiology of experimental preeclampsia needs further investigation.

  13. Peptidoglycan crosslinking relaxation plays an important role in Staphylococcus aureus WalKR-dependent cell viability.

    Directory of Open Access Journals (Sweden)

    Aurelia Delaune

    Full Text Available The WalKR two-component system is essential for viability of Staphylococcus aureus, a major pathogen. We have shown that WalKR acts as the master controller of peptidoglycan metabolism, yet none of the identified regulon genes explain its requirement for cell viability. Transmission electron micrographs revealed cell wall thickening and aberrant division septa in the absence of WalKR, suggesting its requirement may be linked to its role in coordinating cell wall metabolism and cell division. We therefore tested whether uncoupling autolysin gene expression from WalKR-dependent regulation could compensate for its essential nature. Uncoupled expression of genes encoding lytic transglycosylases or amidases did not restore growth to a WalKR-depleted strain. We identified only two WalKR-regulon genes whose expression restored cell viability in the absence of WalKR: lytM and ssaA. Neither of these two genes are essential under our conditions and a ΔlytM ΔssaA mutant does not present any growth defect. LytM is a glycyl-glycyl endopeptidase, hydrolyzing the pentaglycine interpeptide crossbridge, and SsaA belongs to the CHAP amidase family, members of which such as LysK and LytA have been shown to have D-alanyl-glycyl endopeptidase activity, cleaving between the crossbridge and the stem peptide. Taken together, our results strongly suggest that peptidoglycan crosslinking relaxation through crossbridge hydrolysis plays a crucial role in the essential requirement of the WalKR system for cell viability.

  14. Agmatine induced NO dependent rat mesenteric artery relaxation and its impairment in salt-sensitive hypertension.

    Science.gov (United States)

    Gadkari, Tushar V; Cortes, Natalie; Madrasi, Kumpal; Tsoukias, Nikolaos M; Joshi, Mahesh S

    2013-11-30

    l-Arginine and its decarboxylated product, agmatine are important mediators of NO production and vascular relaxation. However, the underlying mechanisms of their action are not understood. We have investigated the role of arginine and agmatine in resistance vessel relaxation of Sprague-Dawley (SD) and Dahl salt-sensitive hypertensive rats. Second or 3rd-order mesenteric arterioles were cannulated in an organ chamber, pressurized and equilibrated before perfusing intraluminally with agonists. The vessel diameters were measured after mounting on the stage of a microscope fitted with a video camera. The gene expression in Dahl rat vessel homogenates was ascertained by real-time PCR. l-Arginine initiated relaxations (EC50, 5.8±0.7mM; n=9) were inhibited by arginine decarboxylase (ADC) inhibitor, difluoromethylarginine (DFMA) (EC50, 18.3±1.3mM; n=5) suggesting that arginine-induced vessel relaxation was mediated by agmatine formation. Agmatine relaxed the SD rat vessels at significantly lower concentrations (EC50, 138.7±12.1μM; n=22), which was compromised by l-NAME (l-N(G)-nitroarginine methyl ester, an eNOS inhibitor), RX821002 (α-2 AR antagonist) and pertussis toxin (G-protein inhibitor). The agmatine-mediated vessel relaxation from high salt Dahl rats was abolished as compared to that from normal salt rats (EC50, 143.9±23.4μM; n=5). The α-2A AR, α-2B AR and eNOS mRNA expression was downregulated in mesenteric arterioles of high-salt treated Dahl hypertensive rats. These findings demonstrate that agmatine facilitated the relaxation via activation of α-2 adrenergic G-protein coupled receptor and NO synthesis, and this pathway is compromised in salt-sensitive hypertension. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Frequency and Temperature Dependence of Anharmonic Phonon Relaxation Rate in Carbon Nanotubes

    International Nuclear Information System (INIS)

    Hepplestone, S P; Srivastava, G P

    2007-01-01

    The relaxation rate of phonon modes in the (10, 10) single wall carbon nanotube undergoing three-phonon interactions at various temperatures has been studied using both qualitative and quantitative approaches based upon Fermi's Golden Rule and a quasi-elastic continuum model for the anharmonic potential. For the quantitative calculations, dispersion relations for the phonon modes were obtained from analytic expressions developed by Zhang et al. The qualitative expressions were derived using simple linear phonon dispersions relations. We show that in the high temperature regime the relaxation rate varies linearly with temperature and with the square of the frequency. In the low temperature regime we show that the relaxation rate varies exponentially with the inverse of temperature. These results have some very interesting implifications for effects for mean free path and thermal conductivity calculations

  16. Temperature dependence of levitation force and its relaxation in a HTS levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Jun; Zhang Xingyi [Key Laboratory of Mechanics on Western Disaster and Environment, Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Zhou Youhe, E-mail: zhouyh@lzu.edu.c [Key Laboratory of Mechanics on Western Disaster and Environment, Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2010-03-01

    Using a modified Gifford-McMahon refrigerator to cool the cylindrical bulk YBaCuO superconductor within the region of 100-10 K, and using an updated high-temperature superconductor (HTS) maglev measurement system, the levitation force and its time relaxation at different temperatures between a YBaCuO bulk superconductor and a permanent magnet (PM) have been measured under zero-field cooling. It is found that decrease the cooling temperature of HTS can decrease the hysteresis of magnetization and increase the maximum levitation force of each hysteresis loop. For the relaxation of levitation force, if the temperature is continually lowered to 10 K after the relaxation measurement at given cooling temperature is performed for 600 s, the levitation force will continue to decrease sharply with the lowering of temperature even though it will get stable if the temperature is not lowered. Our results shown in this work are a benefit to the understanding of levitation systems.

  17. EPA Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Information on sole source aquifers (SSAs) is widely used in assessments under the National Environmental Policy Act and at the state and local level. A national...

  18. Rotational dynamics account for pH-dependent relaxivities of PAMAM dendrimeric, Gd-based potential MRI contrast agents.

    Science.gov (United States)

    Laus, Sabrina; Sour, Angélique; Ruloff, Robert; Tóth, Eva; Merbach, André E

    2005-05-06

    The EPTPA5) chelate, which ensures fast water exchange in GdIII complexes, has been coupled to three different generations (5, 7, and 9) of polyamidoamine (PAMAM) dendrimers through benzylthiourea linkages (H5EPTPA = ethylenepropylenetriamine-N,N,N',N'',N''-pentaacetic acid). The proton relaxivities measured at pH 7.4 for the dendrimer complexes G5-(GdEPTPA)111, G7-(GdEPTPA)253 and G9-(GdEPTPA)1157 decrease with increasing temperature, indicating that, for the first time for dendrimers, slow water exchange does not limit relaxivity. At a given field and temperature, the relaxivity increases from G5 to G7, and then slightly decreases for G9 (r1 = 20.5, 28.3 and 27.9 mM(-1) s(-1), respectively, at 37 degrees C, 30 MHz). The relaxivities show a strong and reversible pH dependency for all three dendrimer complexes. This originates from the pH-dependent rotational dynamics of the dendrimer skeleton, which was evidenced by a combined variable-temperature and multiple-field 17O NMR and 1H relaxivity study performed at pH 6.0 and 9.9 on G5-(GdEPTPA)111. The longitudinal 17O and 1H relaxation rates of the dendrimeric complex are strongly pH-dependent, whereas they are not for the [Gd(EPTPA)(H2O)]2- monomer chelate. The longitudinal 17O and 1H relaxation rates have been analysed by the Lipari-Szabo spectral density functions and correlation times have been calculated for the global motion of the entire macromolecule (tau(gO)) and the local motion of the GdIII chelates on the surface (tau(lO)), correlated by means of an order parameter S2. The dendrimer complex G5-(GdEPTPA)111 has a considerably higher tau(gO) under acidic than under basic conditions (tau(298)gO = 4040 ps and 2950 ps, respectively), while local motions are less influenced by pH (tau(298)lO = 150 and 125 ps). The order parameter, characterizing the rigidity of the macromolecule, is also higher at pH 6.0 than at pH 9.9 (S2 = 0.43 vs 0.36, respectively). The pH dependence of the global correlation time can be

  19. PDE1A inhibition elicits cGMP-dependent relaxation of rat mesenteric arteries

    DEFF Research Database (Denmark)

    Khammy, Makhala Michell; Dalsgaard, Thomas; Larsen, Peter Hjorringgaard

    2017-01-01

    (EC50 = 32 nM). Inhibition of NOS with L-NAME, soluble GC with ODQ, or PKG with Rp-8-Br-PET-cGMP all attenuated PDE1 inhibition-induced relaxation, whereas PKA inhibition with H89 had no effect. CONCLUSION AND IMPLICATIONS: Pde1a was the dominant PDE1 isoform present in VSMC and relaxation mediated...... by PDE1A-inhibition was predominantly driven by enhanced cGMP signalling. These results imply that isoform-selective PDE1 inhibitors are powerful investigative tools allowing examination of physiological and pathological roles of PDE1 isoforms....

  20. Temperature Dependence of Logarithmic-like Relaxational Dynamics of Hydrated tRNA.

    Science.gov (United States)

    Chu, Xiang-Qiang; Mamontov, Eugene; O'Neill, Hugh; Zhang, Qiu

    2013-03-21

    The dynamics of RNA within the β-relaxation region of 10 ps to 1 ns is crucial to its biological function. Because of its simpler chemical building blocks and the lack of the side methyl groups, faster relaxational dynamics of RNA compared to proteins can be expected. However, the situation is actually opposite. In this work, the relaxational dynamics of tRNA is measured by quasielastic neutron scattering and analyzed using the mode coupling theory, originally developed for glass-forming liquids. Our results reveal that the dynamics of tRNA follows a log-decay within the β-relaxation region, which is an important trait demonstrated by the dynamics of proteins. The dynamics of hydrated tRNA and lysozyme compared in the time domain further demonstrate that the slower dynamics of tRNA relative to proteins originates from the difference in the folded states of tRNA and proteins, as well as the influence of their hydration water.

  1. Endothelium-Dependent Relaxation Effect of Apocynum venetum Leaf Extract via Src/PI3K/Akt Signalling Pathway

    Directory of Open Access Journals (Sweden)

    Yeh Siang Lau

    2015-06-01

    Full Text Available Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum venetum leaves (AVLE, also known as Luobuma, exerts its antihypertensive effect via dilating the blood vessels in an endothelium- and concentration-dependent manner with optimal effect seen at as low as 10 µg/mL. A commercial Luoboma “antihypertensive tea” is available commercially in the western province of China. The present study seeks to investigate the underlying cellular mechanisms of the nitric oxide (NO-releasing property of AVLE in rat aortas and human umbilical vein endothelial cells (HUVECs. Endothelium-dependent relaxation induced by AVLE was assessed in organ chambers in the presence or absence of polyethyleneglycol catalase (PP2, 20 µM; inhibitor of Src kinase, wortmannin (30 nM and LY294002 (20 µM; PI3 (phosphatidylinositol3-Kinase inhibitor, NG-nitro-l-arginine (L-NAME, 100 µM; endothelial NO synthase inhibitor (eNOS and ODQ (1 µM; soluble guanylyl cyclase inhibitor. Total nitrite and nitrate (NOx level and protein expression of p-Akt and p-eNOS were measured. AVLE-induced endothelium-dependent relaxation was reduced by PP2, wortmannin and LY294002 and abolished by L-NAME and ODQ. AVLE significantly increased total NOx level in rat aortas and in HUVECs compared to control. It also instigated phosphorylation of Akt and eNOS in cultured HUVECs in a concentration-dependent manner and this was markedly suppressed by PP2, wortmannin and LY294002. AVLE also inhibited superoxide generated from both NADPH oxidase and xanthine/xanthine oxidase system. Taken together, AVLE causes endothelium-dependent NO mediated relaxations of rat aortas through Src/PI3K/Akt dependent NO signalling pathway and possesses superoxide scavenging activity.

  2. SoleSound

    DEFF Research Database (Denmark)

    Zanotto, Damiano; Turchet, Luca; Boggs, Emily Marie

    2014-01-01

    This paper introduces the design of SoleSound, a wearable system designed to deliver ecological, audio-tactile, underfoot feedback. The device, which primarily targets clinical applications, uses an audio-tactile footstep synthesis engine informed by the readings of pressure and inertial sensors...... embedded in the footwear to integrate enhanced feedback modalities into the authors' previously developed instrumented footwear. The synthesis models currently implemented in the SoleSound simulate different ground surface interactions. Unlike similar devices, the system presented here is fully portable...

  3. Electron Tunneling in Lithium Ammonia Solutions Probed by Frequency-Dependent Electron-Spin Relaxation Studies

    Science.gov (United States)

    Maeda, Kiminori; Lodge, Matthew T.J.; Harmer, Jeffrey; Freed, Jack H.; Edwards, Peter P.

    2012-01-01

    Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium-ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T1) and spin-spin (T2) relaxation data indicate an extremely fast transfer or quantum tunneling rate of the solvated electron in these solutions which serves to modulate the hyperfine (Fermi-contact) interaction with nitrogen nuclei in the solvation shells of ammonia molecules surrounding the localized, solvated electron. The donor and acceptor states of the solvated electron in these solutions are the initial and final electron solvation sites found before, and after, the transfer or tunneling process. To interpret and model our electron spin relaxation data from the two observation EPR frequencies requires a consideration of a multi-exponential correlation function. The electron transfer or tunneling process that we monitor through the correlation time of the nitrogen Fermi-contact interaction has a time scale of (1–10)×10−12 s over a temperature range 230–290K in our most dilute solution of lithium in ammonia. Two types of electron-solvent interaction mechanisms are proposed to account for our experimental findings. The dominant electron spin relaxation mechanism results from an electron tunneling process characterized by a variable donor-acceptor distance or range (consistent with such a rapidly fluctuating liquid structure) in which the solvent shell that ultimately accepts the transferring electron is formed from random, thermal fluctuations of the liquid structure in, and around, a natural hole or Bjerrum-like defect vacancy in the liquid. Following transfer and capture of the tunneling electron, further solvent-cage relaxation with a timescale of ca. 10−13 s results in a minor contribution to the electron spin relaxation times. This investigation illustrates the great potential

  4. Electron tunneling in lithium-ammonia solutions probed by frequency-dependent electron spin relaxation studies.

    Science.gov (United States)

    Maeda, Kiminori; Lodge, Matthew T J; Harmer, Jeffrey; Freed, Jack H; Edwards, Peter P

    2012-06-06

    Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium-ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T(1)) and spin-spin (T(2)) relaxation data indicate an extremely fast transfer or quantum tunneling rate of the solvated electron in these solutions which serves to modulate the hyperfine (Fermi-contact) interaction with nitrogen nuclei in the solvation shells of ammonia molecules surrounding the localized, solvated electron. The donor and acceptor states of the solvated electron in these solutions are the initial and final electron solvation sites found before, and after, the transfer or tunneling process. To interpret and model our electron spin relaxation data from the two observation EPR frequencies requires a consideration of a multiexponential correlation function. The electron transfer or tunneling process that we monitor through the correlation time of the nitrogen Fermi-contact interaction has a time scale of (1-10) × 10(-12) s over a temperature range 230-290 K in our most dilute solution of lithium in ammonia. Two types of electron-solvent interaction mechanisms are proposed to account for our experimental findings. The dominant electron spin relaxation mechanism results from an electron tunneling process characterized by a variable donor-acceptor distance or range (consistent with such a rapidly fluctuating liquid structure) in which the solvent shell that ultimately accepts the transferring electron is formed from random, thermal fluctuations of the liquid structure in, and around, a natural hole or Bjerrum-like defect vacancy in the liquid. Following transfer and capture of the tunneling electron, further solvent-cage relaxation with a time scale of ∼10(-13) s results in a minor contribution to the electron spin relaxation times. This investigation illustrates the great

  5. Temperature dependence of electron spin-lattice relaxation of radiation-produced silver atoms in polycrystalline aqueous and glassy organic matrices. Importance of relaxation by tunneling modes in disordered matrices

    International Nuclear Information System (INIS)

    Michalik, J.; Kevan, L.

    1978-01-01

    The electron spin-lattice relaxation of trapped silver atoms in polycrystalline ice matrices and in methanol, ethanol, propylene carbonate, and 2-methyltetrahydrofuran organic glasses has been directly studied as a function of temperature by the saturation-recovery method. Below 40 K the dominant electron spin-lattice relaxation mechanism involves modulation of the electron nuclear dipolar interaction with nuclei in the radical's environment by tunneling of those nuclei between two nearly equal energy configurations. This relaxation mechanism occurs with high efficiency, has a characteristic linear temperature dependence, and is typically found in highly disordered matrices. The efficiency of this relaxation mechanism seems to decrease with decreasing polarity of the matrix. Deuteration experiments show that the tunneling nuclei are protons and in methanol it is shown that the methyl protons have more tunneling modes available than the hydroxyl protons. In polycrystalline ice matrices silver atoms can be stabilized with two different orientations of surrounding water molecules; the efficiency of the tunneling relaxation reflects this difference. From these and previous results on tunneling relaxation of trapped electrons in glassy matrices it appears that tunneling relaxation may be used to distinguish models with different geometrical configurations and to determine the relative rigidity of such configurations around trapped radicals in disordered solids. (author)

  6. Strain Rate Dependence of Compressive Yield and Relaxation in DGEBA Epoxies

    Science.gov (United States)

    Arechederra, Gabriel K.; Reprogle, Riley C.; Clarkson, Caitlyn M.; McCoy, John D.; Kropka, Jamie M.; Long, Kevin N.; Chambers, Robert S.

    2015-03-01

    The mechanical response in uniaxial compression of two diglycidyl ether of bisphenol-A epoxies were studied. These were 828DEA (Epon 828 cured with diethanolamine (DEA)) and 828T403 (Epon 828 cured with Jeffamine T-403). Two types of uniaxial compression tests were performed: A) constant strain rate compression and B) constant strain rate compression followed by a constant strain relaxation. The peak (yield) stress was analyzed as a function of strain rate from Eyring theory for activation volume. Runs at different temperatures permitted the construction of a mastercurve, and the resulting shift factors resulted in an activation energy. Strain and hold tests were performed for a low strain rate where a peak stress was lacking and for a higher strain rate where the peak stress was apparent. Relaxation from strains at different places along the stress-strain curve was tracked and compared. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. Bias Dependent Spin Relaxation in a [110]-InAs/AlSb Two Dimensional Electron System

    Science.gov (United States)

    Hicks, J.; Holabird, K.

    2005-03-01

    Manipulation of electron spin is a critical component of many proposed semiconductor spintronic devices. One promising approach utilizes the Rashba effect by which an applied electric field can be used to reduce the spin lifetime or rotate spin orientation through spin-orbit interaction. The large spin-orbit interaction needed for this technique to be effective typically leads to fast spin relaxation through precessional decay, which may severely limit device architectures and functionalities. An exception arises in [110]-oriented heterostructures where the crystal magnetic field associated with bulk inversion asymmetry lies along the growth direction and in which case spins oriented along the growth direction do not precess. These considerations have led to a recent proposal of a spin-FET that incorporates a [110]-oriented, gate-controlled InAs quantum well channel [1]. We report measurements of the electron spin lifetime as a function of applied electric field in a [110]-InAs 2DES. Measurements made using an ultrafast, mid-IR pump-probe technique indicate that the spin lifetime can be reduced from its maximum to minimum value over a range of less than 0.2V per quantum well at room temperature. This work is supported by DARPA, NSERC and the NSF grant ECS - 0322021. [1] K. C. Hall, W. H. Lau, K. Gundogdu, M. E. Flatte, and T. F. Boggess, Appl. Phys. Lett. 83, 2937 (2003).

  8. Dynamic regulation of GDP binding to G proteins revealed by magnetic field-dependent NMR relaxation analyses.

    Science.gov (United States)

    Toyama, Yuki; Kano, Hanaho; Mase, Yoko; Yokogawa, Mariko; Osawa, Masanori; Shimada, Ichio

    2017-02-22

    Heterotrimeric guanine-nucleotide-binding proteins (G proteins) serve as molecular switches in signalling pathways, by coupling the activation of cell surface receptors to intracellular responses. Mutations in the G protein α-subunit (Gα) that accelerate guanosine diphosphate (GDP) dissociation cause hyperactivation of the downstream effector proteins, leading to oncogenesis. However, the structural mechanism of the accelerated GDP dissociation has remained unclear. Here, we use magnetic field-dependent nuclear magnetic resonance relaxation analyses to investigate the structural and dynamic properties of GDP bound Gα on a microsecond timescale. We show that Gα rapidly exchanges between a ground-state conformation, which tightly binds to GDP and an excited conformation with reduced GDP affinity. The oncogenic D150N mutation accelerates GDP dissociation by shifting the equilibrium towards the excited conformation.

  9. Extracellular Calcium-Dependent Modulation of Endothelium Relaxation in Rat Mesenteric Small Artery

    DEFF Research Database (Denmark)

    Hangaard, Lise; Jessen, Peter B; Kamaev, Dmitrii

    2015-01-01

    The nature of NO- and COX-independent endothelial hyperpolarization (EDH) is not fully understood but activation of small- and intermittent-conductance Ca(2+)-activated K(+) channels (SKCa and IKCa) is important. Previous studies have suggested that the significance of IKCa depends on [Ca(2+)]out...

  10. Orientation dependence in collision induced electronic relaxation studied through van der Waals complexes with isomeric structures. Invited feature article

    International Nuclear Information System (INIS)

    Cheng, P.Y.; Lapierre, L.; Ju, S.S.; DeRose, P.; Dai, H.L.

    1994-01-01

    Weakly bound molecular complexes with more than one well-defined structures provide us with an unique opportunity to investigate dynamic processes induced by intermolecular interactions with specific orientations. The relative orientation of the two interacting molecules or atoms is defined by the complex structure. The effect of the orientation in the spin changing collisions glyoxal (S 1 ) + Ar → glyoxal (T 1 ) + Ar and acetylene (S 1 ) + Ar → acetylene (T) + Ar have been studied by measuring the intersystem crossing (ISC) rates of the glyoxal(S 1 ).Ar and acetylene(S 1 ).Ar complexes with different isomeric structures. Results show that there is a strong orientation dependence in the ISC of glyoxal(S 1 ) induced by interaction with the Ar atom: the Ar atom positioned in the molecular plane is much more effective than in the out-of-plane position in inducing the S 1 → T 1 transition of glyoxal. On the other hand, studies of acetylene(S 1 ).Ar complexes indicate that the Ar-induced ISC rates are nearly identical for the in-plane and out-of-plane positions. Orientation dependence in the collision induced vibrational relaxation process C 2 H 2 (S 1 , v i ) + Ar → C 2 H 2 (S 1 , v f i ) + Ar is also studied by measuring the vibrational predissociation rates of the acetylene(S 1 ).Ar complex isomers. The results indicate that collisions of C 2 H 2 (S 1 , v 3 = 3, 4) with Ar at two orthogonal orientations are equally effective in causing vibrational relaxation of C 2 H 2 . (orig.)

  11. Increased CEST specificity for amide and fast-exchanging amine protons using exchange-dependent relaxation rate.

    Science.gov (United States)

    Zhang, Xiao-Yong; Wang, Feng; Xu, Junzhong; Gochberg, Daniel F; Gore, John C; Zu, Zhongliang

    2018-02-01

    Chemical exchange saturation transfer (CEST) imaging of amides at 3.5 ppm and fast-exchanging amines at 3 ppm provides a unique means to enhance the sensitivity of detection of, for example, proteins/peptides and neurotransmitters, respectively, and hence can provide important information on molecular composition. However, despite the high sensitivity relative to conventional magnetic resonance spectroscopy (MRS), in practice, CEST often has relatively poor specificity. For example, CEST signals are typically influenced by several confounding effects, including direct water saturation (DS), semi-solid non-specific magnetization transfer (MT), the influence of water relaxation times (T 1w ) and nearby overlapping CEST signals. Although several editing techniques have been developed to increase the specificity by removing DS, semi-solid MT and T 1w influences, it is still challenging to remove overlapping CEST signals from different exchanging sites. For instance, the amide proton transfer (APT) signal could be contaminated by CEST effects from fast-exchanging amines at 3 ppm and intermediate-exchanging amines at 2 ppm. The current work applies an exchange-dependent relaxation rate (R ex ) to address this problem. Simulations demonstrate that: (1) slowly exchanging amides and fast-exchanging amines have distinct dependences on irradiation powers; and (2) R ex serves as a resonance frequency high-pass filter to selectively reduce CEST signals with resonance frequencies closer to water. These characteristics of R ex provide a means to isolate the APT signal from amines. In addition, previous studies have shown that CEST signals from fast-exchanging amines have no distinct features around their resonance frequencies. However, R ex gives Lorentzian lineshapes centered at their resonance frequencies for fast-exchanging amines and thus can significantly increase the specificity of CEST imaging for amides and fast-exchanging amines. Copyright © 2017 John Wiley & Sons

  12. Acute Toxicity of Organophosphorus Compounds in Guinea Pigs Is Sex- and Age-Dependent and Cannot Be Solely Accounted for by Acetylcholinesterase Inhibition

    OpenAIRE

    Fawcett, William P.; Aracava, Yasco; Adler, Michael; Pereira, Edna F. R.; Albuquerque, Edson X.

    2008-01-01

    This study was designed to test the hypothesis that the acute toxicity of the nerve agents S-[2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX), O-pinacolyl methylphosphonofluoridate (soman), and O-isopropyl methylphosphonofluoridate (sarin) in guinea pigs is age- and sex-dependent and cannot be fully accounted for by the irreversible inhibition of acetylcholinesterase (AChE). The subcutaneous doses of nerve agents needed to decrease 24-h survival of guine...

  13. Pomegranate Extract Enhances Endothelium-Dependent Coronary Relaxation in Isolated Perfused Hearts from Spontaneously Hypertensive Ovariectomized Rats

    Science.gov (United States)

    Delgado, Nathalie T. B.; Rouver, Wender do N.; Freitas-Lima, Leandro C.; de Paula, Tiago D.-C.; Duarte, Andressa; Silva, Josiane F.; Lemos, Virgínia S.; Santos, Alexandre M. C.; Mauad, Helder; Santos, Roger L.; Moysés, Margareth R.

    2017-01-01

    prevented the decreasing in plasmatic nitrite. We observed a reduction in total cholesterol and LDL in the Sham-PHE group. The treatment with PHE enhances the endothelium-dependent coronary relaxation and improves cardiovascular parameters, which suggests a therapeutic role of PHE. PMID:28101057

  14. Time dependence of volcano inflation: mass influx or viscoelastic relaxation? Insights from Grímsvötn volcano, Iceland

    Science.gov (United States)

    Segall, P.

    2017-12-01

    Distinguishing magma chamber pressurization from relaxation of a viscoelastic aureole surrounding the chamber based on geodetic measurements has remained challenging. Elastic models with mass inflow proportional to the pressure difference between the chamber and a deep reservoir predict exponentially decaying flux. For a spherical chamber surrounded by a Maxwell viscoelastic shell with pressure dependent recharge, the surface deformation is the sum of two exponentials (Segall, 2016). GPS displacements following eruptions of Grímsvötn, Iceland in 2004 and 2011 exhibit rapid post-eruptive inflation (time scale of 0.1 yr), followed by inflation with a much longer time constant. Markov Chain Monte Carlo inversion with the viscoelastic model shows the GPS time series can be fit with viscosity of 2e16 Pa-s, and a relatively incompressible magma, B = beta_c/ (beta_m + beta_c) > 0.6, where beta_m and beta_c are chamber and magma compressibility. The latter appears to conflict with the ratio of erupted volume to geodetically inferred source volume change, rv 10, obtained for the best fitting spherical (Mogi ) source (Hreinsdóttir, 2014). Since rv = 1/B, this implies a relatively compressible melt, B 0.1. Reexamination of the co-eruptive GPS and tilt data with the more general ellipsoidal model of Cervelli (2013), reveals that the best fitting sources are oblate (b/a 3), deeper, and with larger volume changes, rv 3, relative to spherical models. Oblate magma chambers are consistent with seismic tomography. FEM calculations including free surface effects lead to even larger co-eruptive volume changes, smaller rv and hence larger B. I conclude that the data are consistent with rapid post-eruptive inflation driven by viscoelastic relaxation with a relatively incompressible magma, although other interpretations will be discussed.

  15. Acute toxicity of organophosphorus compounds in guinea pigs is sex- and age-dependent and cannot be solely accounted for by acetylcholinesterase inhibition.

    Science.gov (United States)

    Fawcett, William P; Aracava, Yasco; Adler, Michael; Pereira, Edna F R; Albuquerque, Edson X

    2009-02-01

    This study was designed to test the hypothesis that the acute toxicity of the nerve agents S-[2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX), O-pinacolyl methylphosphonofluoridate (soman), and O-isopropyl methylphosphonofluoridate (sarin) in guinea pigs is age- and sex-dependent and cannot be fully accounted for by the irreversible inhibition of acetylcholinesterase (AChE). The subcutaneous doses of nerve agents needed to decrease 24-h survival of guinea pigs by 50% (LD(50) values) were estimated by probit analysis. In all animal groups, the rank order of LD(50) values was sarin > soman > VX. The LD(50) value of soman was not influenced by sex or age of the animals. In contrast, the LD(50) values of VX and sarin were lower in adult male than in age-matched female or younger guinea pigs. A colorimetric assay was used to determine the concentrations of nerve agents that inhibit in vitro 50% of AChE activity (IC(50) values) in guinea pig brain extracts, plasma, red blood cells, and whole blood. A positive correlation between LD(50) values and IC(50) values for AChE inhibition would support the hypothesis that AChE inhibition is a major determinant of the acute toxicity of the nerve agents. However, such a positive correlation was found only between LD(50) values and IC(50) values for AChE inhibition in brain extracts from neonatal and prepubertal guinea pigs. These results demonstrate for the first time that the lethal potencies of some nerve agents in guinea pigs are age- and sex-dependent. They also support the contention that mechanisms other than AChE inhibition contribute to the lethality of nerve agents.

  16. Grid dependency and relaxation of an iteration procedure for flow calculations in stationary hydraulic turbine parts

    Energy Technology Data Exchange (ETDEWEB)

    Iliev, Igor; Markov, Zoran [Faculty of Mechanical Engineering, ' Ss. Cyril and Methodius' University, Skopje (Macedonia, The Former Yugoslav Republic of)

    2014-07-01

    The numerical methods for iterative solving of discretized governing equations often require special treatment for the purpose of achieving not only sufficiently accurate and reliable results, but stable and gradual convergence of the solution too. The general remedy for such challenge, for a certain case, is to use a fine mesh to a certain level and/or to slow down the numerical procedure, a two useful strategies by which numerical instabilities will be avoided on the account of a greater CPU load. This paper presents the employment of these two strategies by conducting a grid dependency analysis for a 2D model of the stay and guide vanes of a hydraulic Francis turbine and furthering the solution to iteration procedure adjustment for a 3D representation of the same model. The ultimate accent is placed on how to deal with a particular numerical instability problem in a pure mathematical fashion without getting into the experimental validation of the results and calibration of the method. (Author)

  17. Time-dependent entropy evolution in microscopic and macroscopic electromagnetic relaxation

    International Nuclear Information System (INIS)

    Baker-Jarvis, James

    2005-01-01

    This paper is a study of entropy and its evolution in the time and frequency domains upon application of electromagnetic fields to materials. An understanding of entropy and its evolution in electromagnetic interactions bridges the boundaries between electromagnetism and thermodynamics. The approach used here is a Liouville-based statistical-mechanical theory. I show that the microscopic entropy is reversible and the macroscopic entropy satisfies an H theorem. The spectral entropy development can be very useful for studying the frequency response of materials. Using a projection-operator based nonequilibrium entropy, different equations are derived for the entropy and entropy production and are applied to the polarization, magnetization, and macroscopic fields. I begin by proving an exact H theorem for the entropy, progress to application of time-dependent entropy in electromagnetics, and then apply the theory to relevant applications in electromagnetics. The paper concludes with a discussion of the relationship of the frequency-domain form of the entropy to the permittivity, permeability, and impedance

  18. The ent-15α-Acetoxykaur-16-en-19-oic Acid Relaxes Rat Artery Mesenteric Superior via Endothelium-Dependent and Endothelium-Independent Mechanisms

    Directory of Open Access Journals (Sweden)

    Êurica Adélia Nogueira Ribeiro

    2012-01-01

    Full Text Available The objective of the study was to investigate the mechanism of the relaxant activity of the ent-15α-acetoxykaur-16-en-19-oic acid (KA-acetoxy. In rat mesenteric artery rings, KA-acetoxy induced a concentration-dependent relaxation in vessels precontracted with phenylephrine. In the absence of endothelium, the vasorelaxation was significantly shifted to the right without reduction of the maximum effect. Endothelium-dependent relaxation was significantly attenuated by pretreatment with L-NAME, an inhibitor of the NO-synthase (NOS, indomethacin, an inhibitor of the cyclooxygenase, L-NAME + indomethacin, atropine, a nonselective antagonist of the muscarinic receptors, ODQ, selective inhibitor of the guanylyl cyclase enzyme, or hydroxocobalamin, a nitric oxide scavenger. The relaxation was completely reversed in the presence of L-NAME + 1 mM L-arginine or L-arginine, an NO precursor. Diterpene-induced relaxation was not affected by TEA, a nonselective inhibitor of K+ channels. The KA-acetoxy antagonized CaCl2-induced contractions in a concentration-dependent manner and also inhibited an 80 mM KCl-induced contraction. The KA-acetoxy did not interfere with Ca2+ release from intracellular stores. The vasorelaxant induced by KA-acetoxy seems to involve the inhibition of the Ca2+ influx and also, at least in part, by endothelial muscarinic receptors activation, NO and PGI2 release.

  19. Investigation of the Temperature Dependence of the Acceptor Center Relaxation Rate in Silicon by the mu^-SR-Method

    CERN Document Server

    Mamedov, T N; Stojkov, A V; Andrianov, D G; Gerlach, D; Zimmermann, U; Gorelkin, V N; Kormann, O; Major, J V; Shevchik, M

    2000-01-01

    Results on the temperature dependence of the residual polarization of negative muons in silicon with phosphorus (3.2 cdot 10^12, 2.3 cdot 10^15 and 4.5 cdot 10^18 cm^-3) and aluminium (2 cdot 10^14 and 2.4 cdot 10^18 cm^-3) impurities are presented. The measurements were carried out in a transverse to the direction of the muon spin magnetic field of 2000 Oe in the temperature range 4.2-300 K. The temperature dependence of the relaxation rate of the magnetic moment of the Al shallow acceptor centre in undeformed silicon is determined for the first time. The constant of the hyperfine interaction between the magnetic moment of the muon and that of the electron shell of the muonic atom A_hf/2pi approx 3 cdot 10^7 s^-1) and the coefficient for capture of free electrons by a neutral aluminium atom in silicon (beta (Al^0) approx 7 cdot 10^-14 cm^3 s^-1 at 30 K) are estimated.

  20. Ab initio relaxation times and time-dependent Hamiltonians within the steepest-entropy-ascent quantum thermodynamic framework

    Science.gov (United States)

    Kim, Ilki; von Spakovsky, Michael R.

    2017-08-01

    Quantum systems driven by time-dependent Hamiltonians are considered here within the framework of steepest-entropy-ascent quantum thermodynamics (SEAQT) and used to study the thermodynamic characteristics of such systems. In doing so, a generalization of the SEAQT framework valid for all such systems is provided, leading to the development of an ab initio physically relevant expression for the intrarelaxation time, an important element of this framework and one that had as of yet not been uniquely determined as an integral part of the theory. The resulting expression for the relaxation time is valid as well for time-independent Hamiltonians as a special case and makes the description provided by the SEAQT framework more robust at the fundamental level. In addition, the SEAQT framework is used to help resolve a fundamental issue of thermodynamics in the quantum domain, namely, that concerning the unique definition of process-dependent work and heat functions. The developments presented lead to the conclusion that this framework is not just an alternative approach to thermodynamics in the quantum domain but instead one that uniquely sheds new light on various fundamental but as of yet not completely resolved questions of thermodynamics.

  1. Kaempferol enhances endothelium-dependent relaxation in the porcine coronary artery through activation of large-conductance a2+-activated K+ channels

    Science.gov (United States)

    Xu, Y C; Leung, S W S; Leung, G P H; Man, R Y K

    2015-01-01

    Background and Purpose Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. Experimental Approach The effect of kaempferol on the relaxation of porcine coronary arteries to endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) relaxing agents was studied in an in vitro organ chamber setup. The whole-cell patch-clamp technique was used to determine the effect of kaempferol on potassium channels in porcine coronary artery smooth muscle cells (PCASMCs). Key Results At a concentration without direct effect on vascular tone, kaempferol (3 × 10−6 M) enhanced relaxations produced by bradykinin and sodium nitroprusside. The potentiation by kaempferol of the bradykinin-induced relaxation was not affected by Nω-nitro-L-arginine methyl ester, an inhibitor of NO synthase (10−4 M) or TRAM-34 plus UCL 1684, inhibitors of intermediate- and small-conductance calcium-activated potassium channels, respectively (10−6 M each), but was abolished by tetraethylammonium chloride, a non-selective inhibitor of calcium-activated potassium channels (10−3 M), and iberiotoxin, a selective inhibitor of large-conductance calcium-activated potassium channel (KCa1.1; 10−7 M). Iberiotoxin also inhibited the potentiation by kaempferol of sodium nitroprusside-induced relaxations. Kaempferol stimulated an outward-rectifying current in PCASMCs, which was abolished by iberiotoxin. Conclusions and Implications The present results suggest that, in smooth muscle cells of the porcine coronary artery, kaempferol enhanced relaxations caused by endothelium-derived and exogenous NO as well as those due to endothelium-dependent hyperpolarization. This vascular effect of kaempferol involved the activation of KCa1.1 channels. PMID:25652142

  2. Kaempferol enhances endothelium-dependent relaxation in the porcine coronary artery through activation of large-conductance Ca(2+) -activated K(+) channels.

    Science.gov (United States)

    Xu, Y C; Leung, S W S; Leung, G P H; Man, R Y K

    2015-06-01

    Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. The effect of kaempferol on the relaxation of porcine coronary arteries to endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) relaxing agents was studied in an in vitro organ chamber setup. The whole-cell patch-clamp technique was used to determine the effect of kaempferol on potassium channels in porcine coronary artery smooth muscle cells (PCASMCs). At a concentration without direct effect on vascular tone, kaempferol (3 × 10(-6) M) enhanced relaxations produced by bradykinin and sodium nitroprusside. The potentiation by kaempferol of the bradykinin-induced relaxation was not affected by N(ω)-nitro-L-arginine methyl ester, an inhibitor of NO synthase (10(-4) M) or TRAM-34 plus UCL 1684, inhibitors of intermediate- and small-conductance calcium-activated potassium channels, respectively (10(-6) M each), but was abolished by tetraethylammonium chloride, a non-selective inhibitor of calcium-activated potassium channels (10(-3) M), and iberiotoxin, a selective inhibitor of large-conductance calcium-activated potassium channel (KCa 1.1; 10(-7) M). Iberiotoxin also inhibited the potentiation by kaempferol of sodium nitroprusside-induced relaxations. Kaempferol stimulated an outward-rectifying current in PCASMCs, which was abolished by iberiotoxin. The present results suggest that, in smooth muscle cells of the porcine coronary artery, kaempferol enhanced relaxations caused by endothelium-derived and exogenous NO as well as those due to endothelium-dependent hyperpolarization. This vascular effect of kaempferol involved the activation of KCa 1.1 channels. © 2015 The British Pharmacological Society.

  3. Temperature and momentum transfer dependence of the dynamics of the α-relaxation in polymer melts. A quasielastic neutron scattering study

    Science.gov (United States)

    Colmenero, J.; Alegría, A.; Arbe, A.; Frick, B.

    1992-12-01

    The dynamics of the α-relaxation in three glass-forming polymeric systems, poly(vinyl methyl ether) (PVME), poly(vinyl chloride) (PVC), and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of quasielastic neutron scattering and compared with the results obtained from relaxation techniques. The results indicate that the dynamics of the α-relaxation in a wide timescale shows a clear non-Debye behaviour and can be well described by means of the same spectral shape, which is found to be independent of temperature and momentum transfer ( Q). Moreover, the Havriliak-Negami characteristic times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. This implies a self-consistent description of the dynamics of the α-relaxation obtained by very different probes. Besides, we found that the Q-dependence of the characteristic times obtained by QENS is given by a power law, τ(Q) ∝ Q - n ( n > 2), n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. These results have main implications about the physical mechanisms behind the dynamics of the α-relaxation.

  4. The age dependence of T2 relaxation times of N-acetyl aspartate, creatine and choline in the human brain at 3 and 4T

    Czech Academy of Sciences Publication Activity Database

    Jirů, F.; Škoch, A.; Wágnerová, D.; Dezortová, M.; Visková, J.; Profant, Oliver; Syka, Josef; Hájek, M.

    2016-01-01

    Roč. 29, č. 3 (2016), s. 284-292 ISSN 0952-3480 Institutional support: RVO:68378041 Keywords : MRS * T2 relaxation times of metabolites * age dependence of T2 Subject RIV: FH - Neurology Impact factor: 2.872, year: 2016

  5. Tocotrienol rich tocomin attenuates oxidative stress and improves endothelium-dependent relaxation in aortae from rats fed a high-fat western diet

    Directory of Open Access Journals (Sweden)

    Saher F Ali

    2016-10-01

    Full Text Available We have previously reported that tocomin, a mixture high in tocotrienol content and also containing tocopherol, acutely preserves endothelial function in the presence of oxidative stress. In this study we investigated whether tocomin treatment would preserve endothelial function in aortae isolated from rats fed a high fat diet known to cause oxidative stress. Wistar hooded rats were fed a western diet (WD, 21% fat or control rat chow (SD, 6% fat for 12 weeks. Tocomin (40 mg/kg/day sc or its vehicle (peanut oil was administered for the last 4 weeks of the feeding regime. Aortae from WD rats showed an impairment of endothelium-dependent relaxation that was associated with an increased expression of the NADPH oxidase Nox2 subunit and an increase in the vascular generation of superoxide measured using L-012 chemiluminescence. The increase in vascular oxidative stress was accompanied by a decrease in basal NO release and impairment of the contribution of NO to ACh-induced relaxation. The impaired relaxation is likely contributed to by a decreased expression of eNOS, calmodulin and phosphorylated Akt and an increase in caveolin-Tocotrienol rich tocomin, which prevented the diet-induced changes in vascular function, reduced vascular superoxide production and abolished the diet-induced changes in eNOS and other protein expression. Using selective inhibitors of nitric oxide synthase (NOS, soluble guanylate cyclase (sGC and calcium activated potassium (KCa channels we demonstrated that tocomin increased NO mediated relaxation, without affecting the contribution of endothelium-dependent hyperpolarization type relaxation to the endothelium-dependent relaxation. The beneficial actions of tocomin in this diet-induced model of obesity suggests that it may have potential to be used as a therapeutic agent to prevent vascular disease in obesity.

  6. Great heterogeneity of commercial fruit juices to induce endothelium-dependent relaxations in isolated porcine coronary arteries: role of the phenolic content and composition.

    Science.gov (United States)

    Auger, Cyril; Pollet, Brigitte; Arnold, Cécile; Marx, Céline; Schini-Kerth, Valérie B

    2015-01-01

    Since polyphenol-rich products such as red wine, grape juice, and grape extracts have been shown to induce potent endothelium-dependent relaxations, we have evaluated whether commercial fruit juices such as those from berries are also able to induce endothelium-dependent relaxations of isolated coronary arteries and, if so, to determine whether this effect is related to their phenolic content. Among the 51 fruit juices tested, 2/12 grape juices, 3/7 blackcurrant juices, 4/5 cranberry juices, 1/6 apple juices, 0/5 orange juices, 2/6 red fruit and berry juices, 3/6 blends of red fruit juices, and 0/4 non-red fruit juices were able to induce relaxations achieving more than 50% at a volume of 1%. The active fruit juices had phenolic contents ranging from 0.31 to 1.86 g GAE/L, which were similar to those of most of the less active juices with the exception of one active grape juice (2.14 g GAE/L) and one active blend of red fruit juices (3.48 g GAE/L). Altogether, these findings indicate that very few commercial fruit juices have the ability to induce potent endothelium-dependent relaxations, and that this effect is not related to their quantitative phenolic content, but rather to their qualitative phenolic composition.

  7. Energy relaxation and separation of a hot electron-hole pair in organic aggregates from a time-dependent wavepacket diffusion method

    International Nuclear Information System (INIS)

    Han, Lu; Liang, WanZhen; Zhao, Yi; Zhong, Xinxin

    2014-01-01

    The time-dependent wavepacket diffusive method [X. Zhong and Y. Zhao, J. Chem. Phys. 138, 014111 (2013)] is extended to investigate the energy relaxation and separation of a hot electron-hole pair in organic aggregates with incorporation of Coulomb interaction and electron-phonon coupling. The pair initial condition generated by laser pulse is represented by a Gaussian wavepacket with a central momentum. The results reveal that the hot electron energy relaxation is very well described by two rate processes with the fast rate much larger than the slow one, consistent with experimental observations, and an efficient electron-hole separation is accomplished accompanying the fast energy relaxation. Furthermore, although the extra energy indeed helps the separation by overcoming the Coulomb interaction, the width of initial wavepacket is much sensitive to the separation efficiency and the narrower wavepacket generates the more separated charges. This behavior may be useful to understand the experimental controversy of the hot carrier effect on charge separation

  8. Endothelium-dependent relaxation of rat aorta to a histamine H3 agonist is reduced by inhibitors of nitric oxide synthase, guanylate cyclase and Na+,K+-ATPase

    Directory of Open Access Journals (Sweden)

    D. M. Djuric

    1996-01-01

    Full Text Available The possible involvement of different effector systems (nitric oxide synthase, guanylate cyclase, β-adrenergic and muscarinic cholinergic receptors, cyclooxygenase and lipoxygenase, and Na+,K+-ATPase was evaluated in a histamine H3 receptor agonist-induced ((Rα-methylhistamine, (Rα-MeHA endothelium-dependent rat aorta relaxation assay. (Rα-MeHA (0.1 nM – 0.01 mM relaxed endothelium-dependent rat aorta, with a pD2 value of 8.22 ± 0.06, compared with a pD2 value of 7.98 ± 0.02 caused by histamine (50% and 70% relaxation, respectively. The effect of (Rα-MeHA (0.1 nM – 0.01 mM was competitively antagonized by thioperamide (1, 10 and 30 nM (pA2 = 9.21 ± 0.40; slope = 1.03 ± 0.35 but it was unaffected by pyrilamine (100 nM, cimetidine (1 μM, atropine (10 μM, propranolol (1 μM, indomethacin (10 μM or nordthydroguaiaretic acid (0.1 mM. Inhibitors of nitric oxide synthase, L-NG-monomethylarginine (L-NMMA, 10 μM and NG-nitro-L-arginine methylester (L-NOARG, 10 μM inhibited the relaxation effect of (Rα-MeHA, by approximately 52% and 70%, respectively. This inhibitory effect of L-NMMA was partially reversed by L-arginine (10 μM. Methylene blue (10 μM and ouabain (10 μM inhibited relaxation (Rα-MeHA-induced by approximately 50% and 90%, respectively. The products of cyclooxygenase and lipoxygenase are not involved in (Rα-MeHA-induced endothelium-dependent rat aorta relaxation nor are the muscarinic cholinergic and β-adrenergic receptors. The results also suggest the involvement of NO synthase, guanylate cyclase and Na+,K+-ATPase in (Rα-MeHA-induced endothelium-dependent rat aorta relaxation.

  9. The contrasting roles of creep and stress relaxation in the time-dependent deformation during in-situ cooling of a nickel-base single crystal superalloy.

    Science.gov (United States)

    Panwisawas, Chinnapat; D'Souza, Neil; Collins, David M; Bhowmik, Ayan

    2017-09-11

    Time dependent plastic deformation in a single crystal nickel-base superalloy during cooling from casting relevant temperatures has been studied using a combination of in-situ neutron diffraction, transmission electron microscopy and modelling. Visco-plastic deformation during cooling was found to be dependent on the stress and constraints imposed to component contraction during cooling, which mechanistically comprises creep and stress relaxation. Creep results in progressive work hardening with dislocations shearing the γ' precipitates, a high dislocation density in the γ channels and near the γ/γ' interface and precipitate shearing. When macroscopic contraction is restricted, relaxation dominates. This leads to work softening from a decreased dislocation density and the presence of long segment stacking faults in γ phase. Changes in lattice strains occur to a similar magnitude in both the γ and γ' phases during stress relaxation, while in creep there is no clear monotonic trend in lattice strain in the γ phase, but only a marginal increase in the γ' precipitates. Using a visco-plastic law derived from in-situ experiments, the experimentally measured and calculated stresses during cooling show a good agreement when creep predominates. However, when stress relaxation dominates accounting for the decrease in dislocation density during cooling is essential.

  10. Heteronuclear relaxation in time-dependent spin systems: 15N-T1ρ dispersion during adiabatic fast passage

    International Nuclear Information System (INIS)

    Konrat, Robert; Tollinger, Martin

    1999-01-01

    A novel NMR experiment comprising adiabatic fast passage techniques for the measurement of heteronuclear self-relaxation rates in fully 15N-enriched proteins is described. Heteronuclear self-relaxation is monitored by performing adiabatic fast passage (AFP) experiments at variable adiabaticity (e.g., variation of RF spin-lock field intensity). The experiment encompasses gradient- selection and sensitivity-enhancement. It is shown that transverse relaxation rates derived with this method are in good agreement with the ones measured by the classical Carr-Purcell-Meiboom-Gill (CPMG) sequences. An application of this method to the study of the carboxyl-terminal LIM domain of quail cysteine and glycine-rich protein qCRP2(LIM2) is presented

  11. The relaxation time approximation

    International Nuclear Information System (INIS)

    Gairola, R.P.; Indu, B.D.

    1991-01-01

    A plausible approximation has been made to estimate the relaxation time from a knowledge of the transition probability of phonons from one state (r vector, q vector) to other state (r' vector, q' vector), as a result of collision. The relaxation time, thus obtained, shows a strong dependence on temperature and weak dependence on the wave vector. In view of this dependence, relaxation time has been expressed in terms of a temperature Taylor's series in the first Brillouin zone. Consequently, a simple model for estimating the thermal conductivity is suggested. the calculations become much easier than the Callaway model. (author). 14 refs

  12. Endothelium-dependent hyperpolarization-related relaxations diminish with age in murine saphenous arteries of both sexes

    DEFF Research Database (Denmark)

    Chennupati, R.; Lamers, W. H.; Koehler, S. E.

    2013-01-01

    nitroprusside and to ACh in the absence of pharmacological inhibitors (indomethacin and L-NAME), were similar in all age groups and sexes, but those mediated by endothelium-derived NO were slightly but significantly increased in 64-week-old male mice. In the presence of inhibitors, 12-week-old animals showed...... pronounced ACh-induced relaxation, which was significantly reduced in 34- and 64-week-old mice of both sexes. The EDH-related component of ACh-induced relaxations was abolished by TRAM-34 (K(Ca)3.1 blocker) or UCL 1684 (K(Ca)2.3 blocker). Although the maximal relaxation induced by NS309 (K-Ca activator......) was not affected by aging, the sensitivity for NS309 significantly decreased with aging. The presence of SKA-31 (K-Ca modulator) potentiated relaxations induced by ACh in arteries of 12-week-old but not older mice. CONCLUSION AND IMPLICATIONS In a small muscular artery of mice of either sex, total endothelium...

  13. Polydatin Restores Endothelium-Dependent Relaxation in Rat Aorta Rings Impaired by High Glucose: A Novel Insight into the PPARβ-NO Signaling Pathway.

    Directory of Open Access Journals (Sweden)

    Yang Wu

    Full Text Available Polydatin, a natural component from Polygonum Cuspidatum, has important therapeutic effects on metabolic syndrome. A novel therapeutic strategy using polydatin to improve vascular function has recently been proposed to treat diabetes-related cardiovascular complications. However, the biological role and molecular basis of polydatin's action on vascular endothelial cells (VECs-mediated vasodilatation under diabetes-related hyperglycemia condition remain elusive. The present study aimed to assess the contribution of polydatin in restoring endothelium-dependent relaxation and to determine the details of its underlying mechanism. By measuring endothelium-dependent relaxation, we found that acetylcholine-induced vasodilation was impaired by elevated glucose (55 mmol/L; however, polydatin (1, 3, 10 μmol/L could restore the relaxation in a dose-dependent manner. Polydatin could also improve the histological damage to endothelial cells in the thoracic aorta. Polydatin's effects were mediated via promoting the expression of endothelial NO synthase (eNOS, enhancing eNOS activity and decreasing the inducible NOS (iNOS level, finally resulting in a beneficial increase in NO release, which probably, at least in part, through activation of the PPARβ signaling pathway. The results provided a novel insight into polydatin action, via PPARβ-NO signaling pathways, in restoring endothelial function in high glucose conditions. The results also indicated the potential utility of polydatin to treat diabetes related cardiovascular diseases.

  14. Sole ulcers in dairy-cattle - associations with season, cow characteristics, disease, and production

    DEFF Research Database (Denmark)

    Enevoldsen, Carsten; Grohn, Y T; Thysen, Iver

    1991-01-01

    lactation and body weight were positively associated with sole ulcer. Heel erosion was associated with sole ulcer depending on season of trimming and parity. Presence of sole ulcer but not heel erosion in a lactation increased the risk of sole ulcer in the subsequent lactation. The interval between...

  15. Cajaninstilbene acid relaxes rat renal arteries: roles of Ca2+ antagonism and protein kinase C-dependent mechanism.

    Directory of Open Access Journals (Sweden)

    Dong-Mei Zhang

    Full Text Available Cajaninstilbene acid (CSA is a major active component present in the leaves of Cajanus cajan (L. Millsp. The present study explores the underlying cellular mechanisms for CSA-induced relaxation in rat renal arteries. Vascular reactivity was examined in arterial rings that were suspended in a Multi Myograph System and the expression of signaling proteins was assessed by Western blotting method. CSA (0.1-10 µM produced relaxations in rings pre-contracted by phenylephrine, serotonin, 9, 11-dideoxy-9α, 11α-epoxymethanoprostaglandin F(2α (U46619, and 60 mM KCl. CSA-induced relaxations did not show difference between genders and were unaffected by endothelium denudation, nor by treatment with N(G-nitro-L-arginine methyl ester, indomethacin, ICI-182780, tetraethylammonium ion, BaCl(2, glibenclamide, 4-aminopyridine or propranolol. CSA reduced contraction induced by CaCl(2 (0.01-5 mM in Ca(2+-free 60 mM KCl solution and by 30 nM (--Bay K8644 in 15 mM KCl solution. CSA inhibited 60 mM KCl-induced Ca(2+ influx in smooth muscle of renal arteries. In addition, CSA inhibited contraction evoked by phorbol 12-myristate 13-acetate (PMA, protein kinase C agonist in Ca(2+-free Krebs solution. Moreover, CSA reduced the U46619- and PMA-induced phosphorylation of myosin light chain (MLC at Ser19 and myosin phosphatase target subunit 1 (MYPT1 at Thr853 which was associated with vasoconstriction. CSA also lowered the phosphorylation of protein kinase C (PKCδ at Thr505. In summary, the present results suggest that CSA relaxes renal arteries in vitro via multiple cellular mechanisms involving partial inhibition of calcium entry via nifedipine-sensitive calcium channels, protein kinase C and Rho kinase.

  16. Spin-polarization dependent carrier recombination dynamics and spin relaxation mechanism in asymmetrically doped (110) n-GaAs quantum wells

    Science.gov (United States)

    Teng, Lihua; Jiang, Tianran; Wang, Xia; Lai, Tianshu

    2018-05-01

    Carrier recombination and electron spin relaxation dynamics in asymmetric n-doped (110) GaAs/AlGaAs quantum wells are investigated with time-resolved pump-probe spectroscopy. The experiment results reveal that the measured carrier recombination time depends strongly on the polarization of pump pulse. With the same pump photon flux densities, the recombination time of spin-polarized carriers is always longer than that of the spin-balanced carriers except at low pump photon flux densities, this anomaly originates from the polarization-sensitive nonlinear absorption effect. Differing from the traditional views, in the low carrier density regime, the D'yakonov-Perel' (DP) mechanism can be more important than the Bir-Aronov-Pikus (BAP) mechanism, since the DP mechanism takes effect, the spin relaxation time in (110) GaAs QWs is shortened obviously via asymmetric doping.

  17. Magnetic relaxation in anisotropic magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1971-01-01

    The line shape and the kinematic and thermodynamic slowing down of the critical and paramagnetic relaxation in axially anisotropic materials are discussed. Kinematic slowing down occurs only in the longitudinal relaxation function. The thermodynamic slowing down occurs in either the transverse...... or longitudinal relaxation function depending on the sign of the axial anisotropy....

  18. EPA Region 1 Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of...

  19. The dependence of shear modulus on dynamic relaxation and evolution of local structural heterogeneity in a metallic glass

    International Nuclear Information System (INIS)

    Huo, L.S.; Zeng, J.F.; Wang, W.H.; Liu, C.T.; Yang, Y.

    2013-01-01

    Starting from the nanoscale structural heterogeneities intrinsic to metallic glasses (MGs), here we show that there are two concurrent contributions to their microscale quasi-static shear modulus G I : one (μ) is related to the atomic bonding strength of solid-like regions and the other (G II ) to the change in the possible configurations of liquid-like regions (dynamic relaxation). Through carefully designed high-rate nanoscale indentation tests, a simple constitutive relation (μ = G I + G II ) is experimentally verified. On a fundamental level, our current work provides a structure–property correlation that may be applicable to a wide range of glassy materials

  20. Composition-dependent hot carrier relaxation dynamics in cesium lead halide (CsPbX{sub 3}, X=Br and I) perovskite nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Heejae; Jung, Seok Il; Kim, Hyo Jin; Cha, Wonhee; Sim, Eunji; Kim, Dongho [Department of Chemistry, Yonsei University, Seoul (Korea, Republic of); Koh, Weon-Kyu [Device Laboratory, Samsung Advanced Institute of Technology, Suwon (Korea, Republic of); Kim, Jiwon [School of Integrated Technology and Underwood International College, Yonsei University, Incheon (Korea, Republic of)

    2017-04-03

    Cesium-based perovskite nanocrystals (NCs) have outstanding photophysical properties improving the performances of lighting devices. Fundamental studies on excitonic properties and hot-carrier dynamics in perovskite NCs further suggest that these materials show higher efficiencies compared to the bulk form of perovskites. However, the relaxation rates and pathways of hot-carriers are still being elucidated. By using ultrafast transient spectroscopy and calculating electronic band structures, we investigated the dependence of halide in Cs-based perovskite (CsPbX{sub 3} with X=Br, I, or their mixtures) NCs on the hot-carrier relaxation processes. All samples exhibit ultrafast (<0.6 ps) hot-carrier relaxation dynamics with following order: CsPbBr{sub 3} (310 fs)>CsPbBr{sub 1.5}I{sub 1.5} (380 fs)>CsPbI{sub 3} NC (580 fs). These result accounts for a reduced light emission efficiency of CsPbI{sub 3} NC compared to CsPbBr{sub 3} NC. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Thickness Dependence of Magnetic Relaxation and E-J Characteristics in Superconducting (Gd-Y)-Ba-Cu-O Films with Strong Vortex Pinning

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Ozgur [ORNL; Sinclair IV, John W [ORNL; Zuev, Yuri L [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL; Cook, Sylvester W [ORNL; Kumar, Dhananjay [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2011-01-01

    The dependence of the critical current density Jc on temperature, magnetic field, and film thickness has been investigated in (Gd-Y)BaCu-oxide materials of 0.7, 1.4, and 2.8 m thickness. Generally, the Jc decreases with film thickness at investigated temperatures and magnetic fields. The nature and strength of the pinning centers for vortices have been identified through angular and temperature measurements, respectively. These films do not exhibit c-axis correlated vortex pinning, but do have correlated defects oriented near the ab-planes. For all film thicknesses studied, strong pinning dominates at most temperatures. The vortex dynamics were investigated through magnetic relaxation studies in the temperature range of 5 77 K in 1 T and 3 T applied magnetic fields, H || surface-normal. The creep rate S is thickness dependent at high temperatures, implying that the pinning energy is also thickness dependent. Maley analyses of the relaxation data show an inverse power law variation for the effective pinning energy Ueff ~ (J0/J) . Finally, the electric field-current density (E-J) characteristics were determined over a wide range of dissipation by combining experimental results from transport, swept field magnetometry (VSM), and Superconducting Quantum Interference Device (SQUID) magnetometry. We develop a self-consistent model of the combined experimental results, leading to an estimation of the critical current density Jc0(T) in the absence of flux creep.

  2. In vivo field dependence of proton relaxation times in human brain, liver and skeletal muscle: a multicenter study

    DEFF Research Database (Denmark)

    Henriksen, O; de Certaines, J D; Spisni, A

    1993-01-01

    and MRS, the in vivo field dispersion of T1 and T2 has been measured in order to evaluate whether ex vivo data are representative for the in vivo situation. Brain, skeletal muscle, and liver of healthy human volunteers were studied. Fifteen MR units with a field strength ranging from 0.08 T to 1.5 T took......T1 and T2 relaxation times are fundamental parameters for signal contrast behaviour in MRI. A number of ex vivo relaxometry studies have dealt with the magnetic field dispersion of T1. By means of multicenter study within the frame of the COMAC BME Concerted Action on Tissue Characterization by MRI......, whereas no significant variations were seen for T2. Our in vivo data were generally in reasonable agreement with proposed models based on ex vivo measurements....

  3. Effects of BM-573 on Endothelial Dependent Relaxation and Increased Blood Pressure at Early Stages of Atherosclerosis.

    Directory of Open Access Journals (Sweden)

    Miguel Romero

    Full Text Available Endothelial dysfunction is considered to be an early event in atherosclerosis and plays a pivotal role in the development, progression and clinical complications of atherosclerosis. Previous studies have shown the beneficial effects of combined inhibition of thromboxane synthase and antagonism of thromboxane receptors by BM-573 on atherosclerosis; however our knowledge about the beneficial effects of BM-573 on endothelial function and increased blood pressure related to early stage of atherosclerosis is limited. In the present study, we investigated the effects of short-term (3 μM, 1 hour and chronic (10 mg/L, 8 weeks treatments with BM-573 on vasodilatory function, nitric oxide (NO bioavailability, oxidative stress and systolic blood pressure in 15 weeks old apolipoprotein E-deficient (ApoE-KO mice. ApoE-KO mice showed a reduced endothelium-derived relaxation. In addition, NO bioavailability was reduced and oxidative stress and blood pressure were increased in ApoE-KO mice versus wild-type mice. BM-573 treatments were able to improve the relaxation profile in ApoE-KO mice. Short-term effects of BM-573 were mainly mediated by an increased phosphorylation of both eNOS and Akt, whereas BM-573 in vivo treatment also reduced oxidative stress and restored NO bioavailability. In addition, chronic administration of BM-573 reduced systolic blood pressure in ApoE-KO mice. In conclusion, pharmacological modulation of TxA2 biosynthesis and biological activities by dual TP antagonism/TxAS inhibition with BM-573, already known to prevent plaque formation, has the potential to correct vasodilatory dysfunction at the early stages of atherosclerosis.

  4. Density-dependent lines of one- and two-electron ions in diagnostics of laboratory plasma. I. The rates of collision relaxation of excited levels

    Energy Technology Data Exchange (ETDEWEB)

    Shevelko, V P; Skobelev, I Yu; Vinogradov, A V [Lebedev Physical Institute, Academy of Sciences of the USSR, Moscow, USSR

    1977-01-01

    Plasma devices with inertial plasma confinement such as laser produced plasmas, exploding wires, plasma focus, etc., which have been rapidly developed during recent years., appear to be very intensive sources of spectral line radiation in far UV and X-ray regions. Analysis of this radiation provides a good tool for plasma diagnostics with very high electron densities up to 10/sup 22/cm/sup -3/. In this work, consisting of two parts, the authors consider the mechanism of the formation of spectral lines in hot and dense plasma. The key point for density diagnostics is the fact that for some ion levels the rate of collisional relaxation has the same order of magnitude as the radiative decay. Thus the intensities of spectral lines arising from these levels show a strong dependence on electron density which makes diagnostics possible. In this paper, emphasis is laid on the calculation of rates of transition between close ion levels induced by electron or ion impact, which usually gives the main contribution to the collisional relaxation constants. The influence of plasma polarization effects on the collision frequency in a dense plasma is also considered.

  5. Local NMR relaxation rates T1-1 and T2-1 depending on the d -vector symmetry in the vortex state of chiral and helical p -wave superconductors

    Science.gov (United States)

    Tanaka, Kenta K.; Ichioka, Masanori; Onari, Seiichiro

    2018-04-01

    Local NMR relaxation rates in the vortex state of chiral and helical p -wave superconductors are investigated by the quasiclassical Eilenberger theory. We calculate the spatial and resonance frequency dependences of the local NMR spin-lattice relaxation rate T1-1 and spin-spin relaxation rate T2-1. Depending on the relation between the NMR relaxation direction and the d -vector symmetry, the local T1-1 and T2-1 in the vortex core region show different behaviors. When the NMR relaxation direction is parallel to the d -vector component, the local NMR relaxation rate is anomalously suppressed by the negative coherence effect due to the spin dependence of the odd-frequency s -wave spin-triplet Cooper pairs. The difference between the local T1-1 and T2-1 in the site-selective NMR measurement is expected to be a method to examine the d -vector symmetry of candidate materials for spin-triplet superconductors.

  6. Relaxation System

    Science.gov (United States)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  7. The dependence of the ultrafast relaxation kinetics of the S2 and S1 states in β-carotene homologs and lycopene on conjugation length studied by femtosecond time-resolved absorption and Kerr-gate fluorescence spectroscopies

    Science.gov (United States)

    Kosumi, Daisuke; Fujiwara, Masazumi; Fujii, Ritsuko; Cogdell, Richard J.; Hashimoto, Hideki; Yoshizawa, Masayuki

    2009-06-01

    The ultrafast relaxation kinetics of all-trans-β-carotene homologs with varying numbers of conjugated double bonds n(n =7-15) and lycopene (n =11) has been investigated using femtosecond time-resolved absorption and Kerr-gate fluorescence spectroscopies, both carried out under identical excitation conditions. The nonradiative relaxation rates of the optically allowed S2(1Bu+1) state were precisely determined by the time-resolved fluorescence. The kinetics of the optically forbidden S1(2Ag-1) state were observed by the time-resolved absorption measurements. The dependence of the S1 relaxation rates upon the conjugation length is adequately described by application of the energy gap law. In contrast to this, the nonradiative relaxation rates of S2 have a minimum at n =9 and show a reverse energy gap law dependence for values of n above 11. This anomalous behavior of the S2 relaxation rates can be explained by the presence of an intermediate state (here called the Sx state) located between the S2 and S1 states at large values of n (such as n =11). The presence of such an intermediate state would then result in the following sequential relaxation pathway S2→Sx→S1→S0. A model based on conical intersections between the potential energy curves of these excited singlet states can readily explain the measured relationships between the decay rates and the energy gaps.

  8. Evidence for Reduced Hydrogen-Bond Cooperativity in Ionic Solvation Shells from Isotope-Dependent Dielectric Relaxation

    Science.gov (United States)

    Cota, Roberto; Ottosson, Niklas; Bakker, Huib J.; Woutersen, Sander

    2018-05-01

    We find that the reduction in dielectric response (depolarization) of water caused by solvated ions is different for H2O and D2O . This isotope dependence allows us to reliably determine the kinetic contribution to the depolarization, which is found to be significantly smaller than predicted by existing theory. The discrepancy can be explained from a reduced hydrogen-bond cooperativity in the solvation shell: we obtain quantitative agreement between theory and experiment by reducing the Kirkwood correlation factor of the solvating water from 2.7 (the bulk value) to ˜1.6 for NaCl and ˜1 (corresponding to completely uncorrelated motion of water molecules) for CsCl.

  9. trans-Caryophyllene, a Natural Sesquiterpene, Causes Tracheal Smooth Muscle Relaxation through Blockade of Voltage-Dependent Ca2+ Channels

    Directory of Open Access Journals (Sweden)

    Jader Santos Cruz

    2012-10-01

    Full Text Available trans-Caryophyllene is a major component in the essential oils of various species of medicinal plants used in popular medicine in Brazil. It belongs to the chemical class of the sesquiterpenes and has been the subject of a number of studies. Here, we evaluated the effects of this compound in airway smooth muscle. The biological activities of trans-caryophyllene were examined in isolated bath organs to investigate the effect in basal tonus. Electromechanical and pharmacomechanical couplings were evaluated through the responses to K+ depolarization and exposure to acetylcholine (ACh, respectively. Isolated cells of rat tracheal smooth muscle were used to investigate trans-caryophyllene effects on voltage-dependent Ca2+ channels by using the whole-cell voltage-clamp configuration of the patch-clamp technique. trans-Caryophyllene showed more efficiency in the blockade of electromechanical excitation-contraction coupling while it has only minor inhibitory effect on pharmacomechanical coupling. Epithelium removal does not modify tracheal smooth muscle response elicited by trans-caryophyllene in the pharmacomechanical coupling. Under Ca2+-free conditions, pre-exposure to trans-caryophyllene did not reduce the contraction induced by ACh in isolated rat tracheal smooth muscle, regardless of the presence of intact epithelium. In the whole-cell configuration, trans-caryophyllene (3 mM, inhibited the inward Ba2+ current (IBa to approximately 50% of control levels. Altogether, our results demonstrate that trans-caryophyllene has anti-spasmodic activity on rat tracheal smooth muscle which could be explained, at least in part, by the voltage-dependent Ca2+ channels blockade.

  10. Transition from Arrhenius to non-Arrhenius temperature dependence of structural relaxation time in glass-forming liquids: continuous versus discontinuous scenario.

    Science.gov (United States)

    Popova, V A; Surovtsev, N V

    2014-09-01

    The temperature dependences of α relaxation time τ(α)(T) of three glass-forming liquids (salol, o-terphenyl, and α-picoline) were investigated by a depolarized light scattering technique. A detailed description of τ(α)(T) near T(A), the temperature of the transition from the Arrhenius law at high temperatures to a non-Arrhenius behavior of τ(α)(T) at lower temperatures, was done. It was found that this transition is quite sharp. If the transition is described as switching from the Arrhenius law to the Vogel-Fulcher-Tammann law, it occurs within the temperature range of about 15 K or less. Most of the known expressions for τ(α)(T) cannot describe this sharp transition. Our analysis revealed that this transition can be described either as a discontinuous transition in the spirit of the frustration-limited domain theory [D. Kivelson, G. Tarjus, X. Zhao, and S. A. Kivelson, Phys. Rev. E 53, 751 (1996)], implying a phase transition, or by a phenomenological expression recently suggested [B. Schmidtke, N. Petzold, R. Kahlau, M. Hofmann, and E. A. Rössler, Phys. Rev. E 86, 041507 (2012)], where the activation energy includes the term depending exponentially on temperature.

  11. Capturing molecular multimode relaxation processes in excitable gases based on decomposition of acoustic relaxation spectra

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Wang, Shu; Zhang, Kesheng

    2017-08-01

    Existing two-frequency reconstructive methods can only capture primary (single) molecular relaxation processes in excitable gases. In this paper, we present a reconstructive method based on the novel decomposition of frequency-dependent acoustic relaxation spectra to capture the entire molecular multimode relaxation process. This decomposition of acoustic relaxation spectra is developed from the frequency-dependent effective specific heat, indicating that a multi-relaxation process is the sum of the interior single-relaxation processes. Based on this decomposition, we can reconstruct the entire multi-relaxation process by capturing the relaxation times and relaxation strengths of N interior single-relaxation processes, using the measurements of acoustic absorption and sound speed at 2N frequencies. Experimental data for the gas mixtures CO2-N2 and CO2-O2 validate our decomposition and reconstruction approach.

  12. Detailing magnetic field strength dependence and segmental artifact distribution of myocardial effective transverse relaxation rate at 1.5, 3.0, and 7.0 T.

    Science.gov (United States)

    Meloni, Antonella; Hezel, Fabian; Positano, Vincenzo; Keilberg, Petra; Pepe, Alessia; Lombardi, Massimo; Niendorf, Thoralf

    2014-06-01

    Realizing the challenges and opportunities of effective transverse relaxation rate (R2 *) mapping at high and ultrahigh fields, this work examines magnetic field strength (B0 ) dependence and segmental artifact distribution of myocardial R2 * at 1.5, 3.0, and 7.0 T. Healthy subjects were considered. Three short-axis views of the left ventricle were examined. R2 * was calculated for 16 standard myocardial segments. Global and mid-septum R2 * were determined. For each segment, an artifactual factor was estimated as the deviation of segmental from global R2 * value. The global artifactual factor was significantly enlarged at 7.0 T versus 1.5 T (P = 0.010) but not versus 3.0 T. At 7.0 T, the most severe susceptibility artifacts were detected in the inferior lateral wall. The mid-septum showed minor artifactual factors at 7.0 T, similar to those at 1.5 and 3.0 T. Mean R2 * increased linearly with the field strength, with larger changes for global heart R2 * values. At 7.0 T, segmental heart R2 * analysis is challenging due to macroscopic susceptibility artifacts induced by the heart-lung interface and the posterior vein. Myocardial R2 * depends linearly on the magnetic field strength. The increased R2 * sensitivity at 7.0 T might offer means for susceptibility-weighted and oxygenation level-dependent MR imaging of the myocardium. Copyright © 2013 Wiley Periodicals, Inc.

  13. Thermal- and pH-Dependent Size Variable Radical Nanoparticles and Its Water Proton Relaxivity for Metal-Free MRI Functional Contrast Agents.

    Science.gov (United States)

    Morishita, Kosuke; Murayama, Shuhei; Araki, Takeru; Aoki, Ichio; Karasawa, Satoru

    2016-09-16

    For development of the metal-free MRI contrast agents, we prepared the supra-molecular organic radical, TEMPO-UBD, carrying TEMPO radical, as well as the urea, alkyl group, and phenyl ring, which demonstrate self-assembly behaviors using noncovalent bonds in an aqueous solution. In addition, TEMPO-UBD has the tertiary amine and the oligoethylene glycol chains (OEGs) for the function of pH and thermal responsiveness. By dynamic light scattering and transmission electron microscopy imaging, the resulting self-assembly was seen to form the spherical nanoparticles 10-150 nm in size. On heating, interestingly, the nanoparticles showed a lower critical solution temperature (LCST) behavior having two-step variation. This double-LCST behavior is the first such example among the supra-molecules. To evaluate of the ability as MRI contrast agents, the values of proton ((1)H) longitudinal relaxivity (r1) were determined using MRI apparatus. In conditions below and above CAC at pH 7.0, the distinguishable r1 values were estimated to be 0.17 and 0.21 mM(-1) s(1), indicating the suppression of fast tumbling motion of TEMPO moiety in a nanoparticle. Furthermore, r1 values became larger in the order of pH 7.0 > 9.0 > 5.0. Those thermal and pH dependencies indicated the possibility of metal-fee MRI functional contrast agents in the future.

  14. Tocotrienol Rich Palm Oil Extract Is More Effective Than Pure Tocotrienols at Improving Endothelium-Dependent Relaxation in the Presence of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Saher F. Ali

    2015-01-01

    Full Text Available Oxidative endothelial dysfunction is a critical initiator of vascular disease. Vitamin E is an effective antioxidant but attempts to use it to treat vascular disorders have been disappointing. This study investigated whether tocotrienols, the less abundant components of vitamin E compared to tocopherols, might be more effective at preserving endothelial function. Superoxide generated by hypoxanthine/xanthine oxidase or rat aorta was measured using lucigenin-enhanced chemiluminescence. The effect of α-tocopherol, α-, δ-, and γ-tocotrienols and a tocotrienol rich palm oil extract (tocomin on levels of superoxide was assessed. Endothelial function in rat aorta was assessed in the presence of the auto-oxidant pyrogallol. Whilst all of the compounds displayed antioxidant activity, the tocotrienols were more effective when superoxide was produced by hypoxanthine/xanthine oxidase whereas tocomin and α-tocopherol were more effective in the isolated aorta. Tocomin and α-tocopherol restored endothelial function in the presence of oxidant stress but α-, δ-, and γ-tocotrienols were ineffective. The protective effect of tocomin was replicated when the tocotrienols were present with, but not without, α-tocopherol. Tocotrienol rich tocomin is more effective than α-tocopherol at reducing oxidative stress and restoring endothelium-dependent relaxation in rat aortae and although α-, δ-, and γ-tocotrienols effectively scavenged superoxide, they did not improve endothelial function.

  15. Tocotrienol Rich Palm Oil Extract Is More Effective Than Pure Tocotrienols at Improving Endothelium-Dependent Relaxation in the Presence of Oxidative Stress

    Science.gov (United States)

    Ali, Saher F.; Woodman, Owen L.

    2015-01-01

    Oxidative endothelial dysfunction is a critical initiator of vascular disease. Vitamin E is an effective antioxidant but attempts to use it to treat vascular disorders have been disappointing. This study investigated whether tocotrienols, the less abundant components of vitamin E compared to tocopherols, might be more effective at preserving endothelial function. Superoxide generated by hypoxanthine/xanthine oxidase or rat aorta was measured using lucigenin-enhanced chemiluminescence. The effect of α-tocopherol, α-, δ-, and γ-tocotrienols and a tocotrienol rich palm oil extract (tocomin) on levels of superoxide was assessed. Endothelial function in rat aorta was assessed in the presence of the auto-oxidant pyrogallol. Whilst all of the compounds displayed antioxidant activity, the tocotrienols were more effective when superoxide was produced by hypoxanthine/xanthine oxidase whereas tocomin and α-tocopherol were more effective in the isolated aorta. Tocomin and α-tocopherol restored endothelial function in the presence of oxidant stress but α-, δ-, and γ-tocotrienols were ineffective. The protective effect of tocomin was replicated when the tocotrienols were present with, but not without, α-tocopherol. Tocotrienol rich tocomin is more effective than α-tocopherol at reducing oxidative stress and restoring endothelium-dependent relaxation in rat aortae and although α-, δ-, and γ-tocotrienols effectively scavenged superoxide, they did not improve endothelial function. PMID:26075031

  16. SOLE: enhanced FIA data analysis capabilities

    Science.gov (United States)

    Michael Spinney; Paul Van Deusen

    2009-01-01

    The Southern On Line Estimator (SOLE), is an Internet-based annual forest inventory and analysis (FIA) data analysis tool developed cooperatively by the National Council for Air and Stream Improvement and the Forest Service, U.S. Department of Agriculture's Forest Inventory and Analysis program at the Southern Research Station. Recent development of SOLE has...

  17. Beneficial effects of calcitriol on hypertension, glucose intolerance, impairment of endothelium-dependent vascular relaxation, and visceral adiposity in fructose-fed hypertensive rats.

    Science.gov (United States)

    Chou, Chu-Lin; Pang, Cheng-Yoong; Lee, Tony J F; Fang, Te-Chao

    2015-01-01

    Besides regulating calcium homeostasis, the effects of vitamin D on vascular tone and metabolic disturbances remain scarce in the literature despite an increase intake with high-fructose corn syrup worldwide. We investigated the effects of calcitriol, an active form of vitamin D, on vascular relaxation, glucose tolerance, and visceral fat pads in fructose-fed rats. Male Wistar-Kyoto rats were divided into 4 groups (n = 6 per group). Group Con: standard chow diet for 8 weeks; Group Fru: high-fructose diet (60% fructose) for 8 weeks; Group Fru-HVD: high-fructose diet as Group Fru, high-dose calcitriol treatment (20 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding; and Group Fru-LVD: high-fructose diet as Group Fru, low-dose calcitriol treatment (10 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding. Systolic blood pressure was measured twice a week by the tail-cuff method. Blood was examined for serum ionized calcium, phosphate, creatinine, glucose, triglycerides, and total cholesterol. Intra-peritoneal glucose intolerance test, aortic vascular reactivity, the weight of visceral fat pads, adipose size, and adipose angiotensin II levels were analyzed at the end of the study. The results showed that the fructose-fed rats significantly developed hypertension, impaired glucose tolerance, heavier weight and larger adipose size of visceral fat pads, and raised adipose angiotensin II expressions compared with the control rats. High- and low-dose calcitriol reduced modestly systolic blood pressure, increased endothelium-dependent aortic relaxation, ameliorated glucose intolerance, reduced the weight and adipose size of visceral fat pads, and lowered adipose angiotensin II expressions in the fructose-fed rats. However, high-dose calcitriol treatment mildly increased serum ionized calcium levels (1.44 ± 0.05 mmol/L). These results suggest a protective role of calcitriol treatment on endothelial function, glucose

  18. Beneficial effects of calcitriol on hypertension, glucose intolerance, impairment of endothelium-dependent vascular relaxation, and visceral adiposity in fructose-fed hypertensive rats.

    Directory of Open Access Journals (Sweden)

    Chu-Lin Chou

    Full Text Available Besides regulating calcium homeostasis, the effects of vitamin D on vascular tone and metabolic disturbances remain scarce in the literature despite an increase intake with high-fructose corn syrup worldwide. We investigated the effects of calcitriol, an active form of vitamin D, on vascular relaxation, glucose tolerance, and visceral fat pads in fructose-fed rats. Male Wistar-Kyoto rats were divided into 4 groups (n = 6 per group. Group Con: standard chow diet for 8 weeks; Group Fru: high-fructose diet (60% fructose for 8 weeks; Group Fru-HVD: high-fructose diet as Group Fru, high-dose calcitriol treatment (20 ng / 100 g body weight per day 4 weeks after the beginning of fructose feeding; and Group Fru-LVD: high-fructose diet as Group Fru, low-dose calcitriol treatment (10 ng / 100 g body weight per day 4 weeks after the beginning of fructose feeding. Systolic blood pressure was measured twice a week by the tail-cuff method. Blood was examined for serum ionized calcium, phosphate, creatinine, glucose, triglycerides, and total cholesterol. Intra-peritoneal glucose intolerance test, aortic vascular reactivity, the weight of visceral fat pads, adipose size, and adipose angiotensin II levels were analyzed at the end of the study. The results showed that the fructose-fed rats significantly developed hypertension, impaired glucose tolerance, heavier weight and larger adipose size of visceral fat pads, and raised adipose angiotensin II expressions compared with the control rats. High- and low-dose calcitriol reduced modestly systolic blood pressure, increased endothelium-dependent aortic relaxation, ameliorated glucose intolerance, reduced the weight and adipose size of visceral fat pads, and lowered adipose angiotensin II expressions in the fructose-fed rats. However, high-dose calcitriol treatment mildly increased serum ionized calcium levels (1.44 ± 0.05 mmol/L. These results suggest a protective role of calcitriol treatment on endothelial

  19. Perinatal development influences mechanisms of bradykinin-induced relaxations in pulmonary resistance and conduit arteries differently.

    Science.gov (United States)

    Boels, P J; Deutsch, J; Gao, B; Haworth, S G

    2001-07-01

    prostaglandin- and NO-synthesis whereas those to SP (at all ages) and ACH (in the adult) do not. In RPA, BYK-relaxations develop from being completely dependant on the sole release of NO (foetus) to being almost completely independent of it (adult), a situation mimicked partially by SP but not by ACH, which, in new-born RPA is completely dependent on NO. BYK-relaxations in postnatal RPA depend on the release of a hyperpolarising factor generated through an SKF525a-sensitive pathway in conjunction with NO. The mechanisms of endothelium-dependent BYK-relaxations in the pulmonary vascular bed undergo diverging alterations, depending on the stage of development and arterial size/function. These changes are specific for BYK as they differ from those obtained from ACH or SP.

  20. Plasmon-mediated energy relaxation in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, D. K. [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Somphonsane, R. [Department of Physics, King Mongkut' s Institute of Technology, Ladkrabang, Bangkok 10520 (Thailand); Ramamoorthy, H.; Bird, J. P. [Department of Electrical Engineering, University at Buffalo, the State University of New York, Buffalo, New York 14260-1500 (United States)

    2015-12-28

    Energy relaxation of hot carriers in graphene is studied at low temperatures, where the loss rate may differ significantly from that predicted for electron-phonon interactions. We show here that plasmons, important in the relaxation of energetic carriers in bulk semiconductors, can also provide a pathway for energy relaxation in transport experiments in graphene. We obtain a total loss rate to plasmons that results in energy relaxation times whose dependence on temperature and density closely matches that found experimentally.

  1. Sole risk and non-consent

    International Nuclear Information System (INIS)

    Winsor, Tom

    1994-01-01

    This article discusses the subjects of sole risk and non-consent in joint operation agreements as used by oil and gas joint ventures in the United Kingdom. The difference between these two concepts is examined in detail. (UK)

  2. EPA Region 1 Sole Source Aquifers

    Science.gov (United States)

    This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of drinking water for a given aquifer service area; that is, an aquifer which is needed to supply 50% or more of the drinking water for the area and for which there are no reasonable alternative sources should the aquifer become contaminated.The aquifers were defined by a EPA hydrogeologist. Aquifer boundaries were then drafted by EPA onto 1:24000 USGS quadrangles. For the coastal sole source aquifers the shoreline as it appeared on the quadrangle was used as a boundary. Delineated boundaries were then digitized into ARC/INFO.

  3. Relaxed states with plasma flow

    International Nuclear Information System (INIS)

    Avinash, K.; Taylor, J.B.

    1991-01-01

    In the theory of relaxation, a turbulent plasma reaches a state of minimum energy subject to constant magnetic helicity. In this state the plasma velocity is zero. Attempts have been made by introducing a number of different constraints, to obtain relaxed states with plasma flow. It is shown that these alternative constraints depend on two self-helicities, one for ions, and one for electrons. However, whereas there are strong arguments for the effective invariance of the original magnetic-helicity, these arguments do not apply to the self-helicities. Consequently the existence of relaxed states with flow remains in doubt. (author)

  4. Is refinancing solely motivated by misappropriation?

    Directory of Open Access Journals (Sweden)

    Chun Liu

    2012-12-01

    Full Text Available Misappropriation has become the accepted explanation for the refinancing behavior of Chinese listed companies, although the evidence in support of such an explanation is worthy of further discussion. We argue that if a planned refinancing exercise does not become a reality, post-refinancing performance depends on the initial motivation for refinancing, i.e. misappropriation or the maximization of firm value. The success and failure samples provided by the approval system of the Chinese securities market provide us with a natural laboratory in which to distinguish between these two possible motivations for the refinancing behavior of Chinese listed firms. The results show the post-refinancing performance of firms in the success sample to be significantly better than the performance in the failure sample, with the difference even more significant when larger agency costs or more financial constraints exist. These findings indicate that Chinese listed companies do not engage in refinancing for misappropriation purposes alone. Rather, refinancing is more likely to be a rational choice made in full consideration of the costs and benefits. This paper provides new ideas for reexamining the motivations for the refinancing behavior of China’s listed firms. It also has one major policy implication. That is, relaxing and/or simplifying the country’s refinancing regulations could help to improve the efficiency of resource allocation in the Chinese securities market.

  5. A NEW 3D DESIGN METHOD FOR FOOTWEAR SOLES USING DELCAM PowerSHAPE-e SYSTEM

    Directory of Open Access Journals (Sweden)

    IONESCU Cozmin

    2016-05-01

    Full Text Available Design methods of soles and soles injection moulds must be accurate, timely and at the same time, accessible to a wide category of soles and injection moulds designers and manufacturers. For designing soles and injection moulds for soles, various dedicated CAD/CAM systems have been developed, such as: Delcam Shoe Solution (3D, Delcam PowerSHAPE-e (2D and 3D, Padsy II (2D and Padsy III (3D, Shoemaster System (2D and 3D, Lectra System (2D and 3D, Parmel System (2D and ATOS II System (3D. These systems are equipped with colour displays, plotters, digitizers, terminals and other equipment dedicated for computer aided design activities. Designing 3D soles models using computer systems enables the prevention of ambiguities inherited from 2D drawings, thus reducing errors and remanufacturing. Depending on the design complexity of soles, the technical means available for copying shoe soles and the technologies at the disposal of the soles manufacturers, soles and injection moulds designers adopt various design methods. Not all CAD/CAM systems are accessible for all users, because often their purchasing costs are high. Design method developed and presented in this paper, uses Delcam PowerSHAPE software program, which has the advantage that it can be accessed free of charge from the manufacturer's website. At the same time, this software program provides the user with all the necessary tools and instruments needed to design the most complex injection moulds and footwear sole.

  6. Endothelium-dependent relaxant responses to selective 5-HT(1B/1D) receptor agonists in the isolated middle cerebral artery of the rat

    DEFF Research Database (Denmark)

    Hansen-Schwartz, Jacob; Løvland Hoel, Natalie; Nilsson, Elisabeth

    2003-01-01

    perfused. Luminally added 5- hydroxytryptamine (5-HT), sumatriptan and rizatriptan induced maximal dilatations of 22 +/- 4, 10 +/- 2 and 13 +/- 5%, respectively, compared to the resting diameter. The relaxant effect of sumatriptan was blocked by the 5- HT(1B/1D) receptor selective antagonist GR 55562 (10......The vasomotor effects of triptans in the middle cerebral artery (MCA) of rats were studied using the pressurised arteriography method and in vitro vessel baths. Using the arteriograph, MCAs from Sprague-Dawley rats were mounted on two glass micropipettes, pressurised to 85 mm Hg and luminally...... response to 5-HT and triptans. Using the vessel bath technique, MCA segments were mounted on two metal wires. The relaxant responses to sumatriptan could not be reproduced using this model; instead, weak contractile responses (6 +/- 3% of submaximal contractile capacity) were observed. The difference...

  7. Dielectric relaxation dependent memory elements in pentacene/[6,6]-phenyl-C61-butyric acid methyl ester bi-layer field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoungnam

    2015-03-02

    We fabricate a pentacene/[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM) bi-layer field effect transistor (FET) featuring large hysteresis that can be used as memory elements. Intentional introduction of excess electron traps in a PCBM layer by exposure to air caused large hysteresis in the FET. The memory window, characterized by the threshold voltage difference, increased upon exposure to air and this is attributed to an increase in the number of electron trapping centers and (or) an increase in the dielectric relaxation time in the underlying PCBM layer. Decrease in the electron conduction in the PCBM close to the SiO{sub 2} gate dielectric upon exposure to air is consistent with the increase in the dielectric relaxation time, ensuring that the presence of large hysteresis in the FET originates from electron trapping at the PCBM not at the pentacene. - Highlights: • Charge trapping-induced memory effect was clarified using transistors. • The memory window can be enhanced by controlling charge trapping mechanism. • Memory transistors can be optimized by controlling dielectric relaxation time.

  8. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin......-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...... the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent....

  9. Assessment of protein solution versus crystal structure determination using spin- diffusion-suppressed NOE and heteronuclear relaxation data

    International Nuclear Information System (INIS)

    LeMaster, David M.

    1997-01-01

    A spin-diffusion-suppressed NOE buildup series has been measured for E. coli thioredoxin.The extensive 13C and 15N relaxation data previously reported for this protein allow for direct interpretation of dynamical contributions to the 1H-1H cross-relaxation rates for a large proportion of the NOE cross peaks. Estimates of the average accuracy for these derived NOE distances are bounded by 4% and 10%, based on a comparison to the corresponding X-ray distances. An independent fluctuation model is proposed for prediction of the dynamical corrections to 1H-1H cross-relaxation rates, based solely on experimental structural and heteronuclear relaxation data. This analysis is aided by the demonstration that heteronuclear order parameters greater than 0.6 depend only on the variance of the H-X bond orientation,independent of the motional model in either one- or two-dimensional diffusion (i.e., 1- S2 = 3/4 sin2 2 θσ). The combination of spin-diffusion-suppressed NOE data and analysis of dynamical corrections to 1H-1H cross-relaxation rates based on heteronuclear relaxation data has allowed for a detailed interpretation of various discrepancies between the reported solution and crystal structures

  10. Dependence of cross-relaxation on temperature and concentration from the 1D2 level of Pr3+ in YPO4

    International Nuclear Information System (INIS)

    Collins, John; Geen, Megan; Bettinelli, M.; Di Bartolo, B.

    2012-01-01

    We report on the role of cross-relaxation in the decay of the 1 D 2 level of trivalent Pr in YPO 4 in crystals with Pr concentrations of 0.1%, 1%, 2%, and 5%. We have found that the 1 D 2 level decay is purely radiative in the low-doped system. As the Pr concentration is increased, the 1 D 2 luminescence is quenched due to a cross-relaxation energy transfer between two Pr ions. The temporal behavior of the 1 D 2 luminescence following pulsed excitation has been monitored in each sample at temperatures between 30 K and 300 K, and all decay curves were fit to the Yokota–Tanimoto model. The decay times decrease as temperature increases, due to an increase in both the radiative rate and the energy transfer rate with temperature. There is little evidence of diffusion at any temperature, even in the more concentrated samples. We have also fit the decay curves using the LumiTrans computer simulation. A comparison of the fits to the decay curves of the two methods is presented. - Highlights: ► We present data on the decay of the 1 D 2 level of Pr in YPO 4 from 30–300 K. ► We determine the 1 D 2 cross-relaxation rate throughout that temperature range. ► Fits to the data indicate diffusion among the Pr ions is negligible. ► Radiative efficiencies of the 1 D 2 level are determined.

  11. The change of longitudinal relaxation rate in oxygen enhanced pulmonary MRI depends on age and BMI but not diffusing capacity of carbon monoxide in healthy never-smokers.

    Directory of Open Access Journals (Sweden)

    Simon Sven Ivan Kindvall

    Full Text Available Oxygen enhanced pulmonary MRI is a promising modality for functional lung studies and has been applied to a wide range of pulmonary conditions. The purpose of this study was to characterize the oxygen enhancement effect in the lungs of healthy, never-smokers, in light of a previously established relationship between oxygen enhancement and diffusing capacity of carbon monoxide in the lung (DL,CO in patients with lung disease.In 30 healthy never-smoking volunteers, an inversion recovery with gradient echo read-out (Snapshot-FLASH was used to quantify the difference in longitudinal relaxation rate, while breathing air and 100% oxygen, ΔR1, at 1.5 Tesla. Measurements were performed under multiple tidal inspiration breath-holds.In single parameter linear models, ΔR1 exhibit a significant correlation with age (p = 0.003 and BMI (p = 0.0004, but not DL,CO (p = 0.33. Stepwise linear regression of ΔR1 yields an optimized model including an age-BMI interaction term.In this healthy, never-smoking cohort, age and BMI are both predictors of the change in MRI longitudinal relaxation rate when breathing oxygen. However, DL,CO does not show a significant correlation with the oxygen enhancement. This is possibly because oxygen transfer in the lung is not diffusion limited at rest in healthy individuals. This work stresses the importance of using a physiological model to understand results from oxygen enhanced MRI.

  12. Breathing and Relaxation

    Science.gov (United States)

    ... Find a Doctor Relaxation is the absence of tension in muscle groups and a minimum or absence ... Drill Meditation Progressive Muscle Relaxation Minimizing Shortness of Breath Visualization This information has been approved by Shelby ...

  13. Pressure dependence of thermal conductivity and specific heat in CeRh2Si2 measured by an extended thermal relaxation method

    Science.gov (United States)

    Nishigori, Shijo; Seida, Osamu

    2018-05-01

    We have developed a new technique for measuring thermal conductivity and specific heat under pressure by improving a thermal relaxation method. In this technique, a cylindrical sample with a small disc heater is embedded in the pressure-transmitting medium, then temperature variations of the sample and heater were directly measured by thermocouples during a heating and cooling process. Thermal conductivity and specific heat are estimated by comparing the experimental data with temperature variations simulated by a finite element method. The obtained thermal conductivity and specific heat of the test sample CeRh2Si2 exhibit a small enhancement and a clear peak arising from antiferromagnetic transition, respectively. The observation of these typical behaviors for magnetic compounds indicate that the technique is valid for the study on thermal properties under pressure.

  14. pH-Dependent Regulation of the Relaxation Rate of the Radical Anion of the Secondary Quinone Electron Acceptor QB in Photosystem II As Revealed by Fourier Transform Infrared Spectroscopy.

    Science.gov (United States)

    Nozawa, Yosuke; Noguchi, Takumi

    2018-05-15

    Photosystem II (PSII) is a protein complex that performs water oxidation using light energy during photosynthesis. In PSII, electrons abstracted from water are eventually transferred to the secondary quinone electron acceptor, Q B , and upon double reduction, Q B is converted to quinol by binding two protons. Thus, excess electron transfer in PSII increases the pH of the stroma. In this study, to investigate the pH-dependent regulation of the electron flow in PSII, we have estimated the relaxation rate of the Q B - radical anion in the pH region between 5 and 8 by direct monitoring of its population using light-induced Fourier transform infrared difference spectroscopy. The decay of Q B - by charge recombination with the S 2 state of the water oxidation center in PSII membranes was shown to be accelerated at higher pH, whereas that of Q A - examined in the presence of a herbicide was virtually unaffected at pH ≤7.5 and slightly slowed at pH 8. These observations were consistent with the previous studies that included rather indirect monitoring of the Q B - and Q A - decays using fluorescence detection. The accelerated relaxation of Q B - was explained by the shift of a redox equilibrium between Q A - and Q B - to the Q A - side due to the decrease in the redox potential of Q B at higher pH, which is induced by deprotonation of a single amino acid residue near Q B . It is proposed that this pH-dependent Q B - relaxation is one of the mechanisms of electron flow regulation in PSII for its photoprotection.

  15. Conformational exchange in pseudoazurin: different kinds of microsecond to millisecond dynamics characterized by their pH and buffer dependence using 15N NMR relaxation.

    Science.gov (United States)

    Hass, Mathias A S; Vlasie, Monica D; Ubbink, Marcellus; Led, Jens J

    2009-01-13

    The dynamics of the reduced form of the blue copper protein pseudoazurin from Alcaligenes faecalis S-6 was investigated using (15)N relaxation measurements with a focus on the dynamics of the micro- to millisecond time scale. Different types of conformational exchange processes are observed in the protein on this time scale. At low pH, the protonation of the C-terminal copper-ligated histidine, His81, is observed. A comparison of the exchange rates in the presence and absence of added buffers shows that the protonation is the rate-limiting step at low buffer concentrations. This finding agrees with previous observations for other blue copper proteins, e.g., amicyanin and plastocyanin. However, in contrast to plastocyanin but similar to amicyanin, a second conformational exchange between different conformations of the protonated copper site is observed at low pH, most likely triggered by the protonation of His81. This process has been further characterized using CPMG dispersion methods and is found to occur with a rate of a few thousands per second. Finally, micro- to millisecond motions are observed in one of the loop regions and in the alpha-helical regions. These motions are unaffected by pH and are unrelated to the conformational changes in the active site of pseudoazurin.

  16. Mechanical relaxation in glasses

    International Nuclear Information System (INIS)

    Hiki, Y.

    2004-01-01

    The basic properties of glasses and the characteristics of mechanical relaxation in glasses were briefly reviewed, and then our studies concerned were presented. Experimental methods adopted were viscosity, internal friction, ultrasonic attenuation, and Brillouin scattering measurements. The specimens used were several kinds of inorganic, organic, and metallic glasses. The measurements were mainly carried out from the room temperature up to the glass transition temperature, and the relaxation time was determined as a function of temperature. The 'double relaxation' composed of two Arrhenius-type relaxations was observed in many materials. In both relaxations, the 'compensation effect' showing a correlation of the pre-exponential factor and the activation energy was observed. These results were explained by considering the 'complex relaxation' due to cooperative motions of atoms or group of atoms. Values of activation energy near the glass transition determined by the various experimental methods were compared with each other

  17. Stress relaxation under cyclic electron irradiation

    International Nuclear Information System (INIS)

    Bystrov, L.N.; Reznitskij, M.E.

    1990-01-01

    The kinetics of deformation process in a relaxating sample under 2 MeV electron cyclic irradiation was studied experimentally. The Al-Mg alloys with controllable and different (in dislocation density precipitate presence and their character) structure were used in experiments. It was established that after the beam was switched on the deformation rate increased sharply and then, during prolonged irradiation, in a gradual manner. After the switching-off the relaxation rate decreases by jumps up to values close to extrapolated rates of pre-radiation relaxation. The exhibition of these effects with radiation switching-off and switchin-on is dependent on the initial rate of thermal relaxation, the test temperature, the preliminary cold deformation and the dominating deformation dislocation mechanism. The preliminary cold deformation and test temperature elevation slightly decrease the effect of instantaneous relaxation acceleration with the irradiation switch-on. 17 refs., 5 figs

  18. Vibrational and Rotational Energy Relaxation in Liquids

    DEFF Research Database (Denmark)

    Petersen, Jakob

    Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...

  19. Relaxation properties in classical diamagnetism

    Science.gov (United States)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  20. 25 CFR 140.1 - Sole power to appoint.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Sole power to appoint. 140.1 Section 140.1 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FINANCIAL ACTIVITIES LICENSED INDIAN TRADERS § 140.1 Sole power to appoint. The Commissioner of Indian Affairs shall have the sole power and authority to...

  1. Efeito dos ácidos graxos ômega-3 sobre o relaxamento-dependente do endotélio em coelhos hipercolesterolêmicos Effects of omega-3 fatty acids on endothelium-dependent relaxation in hypercholesterolemic rabbits

    Directory of Open Access Journals (Sweden)

    Paulo Afonso Ribeiro Jorge

    1997-07-01

    Full Text Available OBJETIVO: Estudar o efeito dos ácidos graxos ômega-3 sobre o relaxamento-dependente do endotélio, o colesterol plasmático, as LDL, VLDL, HDL, triglicérides e a peroxidação lipídica das partículas de LDL-nativas, oxidadas e da parede arterial. MÉTODOS: Coelhos da raça Nova Zelândia foram submetidos a dieta enriquecida com colesterol (0,5% e gordura de coco (2%, por 30 dias e separados em grupo hipercolesterolemia (H e ômega-3 (O-3, sendo administrado ao O-3 ácidos graxos ômega-3 na dose de 300mg/kg/dia, durante 15 dias, através de gavagem. O colesterol plasmático, triglicérides, LDL-colesterol, VLDL e HDL-colesterol foram medidos através de kits enzimáticos e os resultados expressos em mg/dl. As LDL foram obtidas por ultracentrifugação e oxidadas através da exposição ao Cu++. A peroxidação lipídica das LDL e da parede da aorta foi mensurada pela dosagem do malondialdeido (MDA. A função endotelial foi avaliada por curvas de concentração-efeito obtidas pela acetilcolina e nitroprussiato, após contração com norepinefrina. RESULTADOS: Houve aumento do colesterol plasmático e das VLDL, sem interferência nos níveis de LDL e HDL, no O-3. Observou-se redução significante dos triglicérides. Verificou-se aumento significante do teor de MDA nas LDL-nativas e oxidadas, assim como na parede arterial. O relaxamento-dependente do endotélio foi significativamente menor no O-3. CONCLUSÃO: A administração de ácidos graxos ômega-3 na dosagem de 300/mg/kg/dia, a coelhos hipercolesterolêmicos aumentou o colesterol e as VLDL plasmáticas, enquanto reduziu os triglicérides. O relaxamento-dependente do endotélio foi menor que no grupo H.PURPOSE: To study the effect of omega-3 fatty acid on endothelium-dependent relaxation, total plasma cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides levels as well as, the malondialdehyde (MDA content of the LDL particles and arterial wall. METHODS: Fourteen male rabbits

  2. Relaxation characteristics of hastelloy X

    International Nuclear Information System (INIS)

    Suzuki, Kazuhiko

    1980-02-01

    Relaxation diagrams of Hastelloy X (relaxation curves, relaxation design diagrams, etc.) were generated from the creep constitutive equation of Hastelloy X, using inelastic stress analysis code TEPICC-J. These data are in good agreement with experimental relaxation data of ORNL-5479. Three typical inelastic stress analyses were performed for various relaxation behaviors of the high-temperature structures. An attempt was also made to predict these relaxation behaviors by the relaxation curves. (author)

  3. ALGORITHMS FOR THE PROGRAMMING OF FOOTWEAR SOLES MOULDS ON WORKING POSTS OF INJECTION MACHINES

    Directory of Open Access Journals (Sweden)

    LUCA Cornelia

    2014-05-01

    Full Text Available The moulds stock necessary for realization in rhythmically conditions, a certain volume of footwear soles depends on some criterions such as: the range of soles for footwear volume daily realized, the sizes structure of those soles for footwear and, respectively, the sizes tally, the technological cycle for an used mould depending on the equipment efficiency, the provide necessity of spare moulds, the using and fixing conditions etc. From the efficiency point of view, the equipments may have two working posts, or more working posts (always, an even number, as 6, 12, 24, 40 posts. Footwear soles manufacturing takes into account the percentage distribution of the size numbers of the size series. When o portative assembly is used for the manufacturing of the footwear soles using the injection with “n” working posts, it is very important an optimum distribution of the working posts. The disadvantages of these equipments are the situations of the no equilibrium programming of the moulds, so that, in one time, some working posts spread out of the work. The paper presents some practical and theoretical solutions for moulds stock programming in portative assembly for footwear soles injection, so that an optimum equilibrium degree of the working posts will obtain

  4. Properties of the manganese(II) binding site in ternary complexes of Mnter dot ADP and Mnter dot ATP with chloroplast coupling factor 1: Magnetic field dependence of solvent sup 1 H and sup 2 H NMR relaxation rates

    Energy Technology Data Exchange (ETDEWEB)

    Haddy, A.E.; Frasch, W.D.; Sharp, R.R. (Univ. of Michigan, Ann Arbor (USA))

    1989-05-02

    The influence of the binding of ADP and ATP on the high-affinity Mn(II) binding site of chloroplast coupling factor 1 (CF{sub 1}) was studied by analysis of field-dependent solvent proton and deuteron spin-lattice relaxation data. In order to characterize metal-nucleotide complexes of CF{sub 1} under conditions similar to those of the NMR experiments, the enzyme was analyzed for bound nucleotides and Mn(II) after incubation with AdN and MnCl{sub 2} and removal of labile ligands by extensive gel filtration chromatography. In the field-dependent NMR experiments, the Mn(II) binding site of CF{sub 1} was studied for three mole ratios of added Mn(II) to CF{sub 1}, 0.5, 1.0, and 1.5, in the presence of an excess of either ADP or ATP. The results were extrapolated to zero Mn(II) concentration to characterize the environment of the first Mn(II) binding site of Cf{sub 1}. In the presence of both adenine nucleotides, pronounced changes in the Mn(II) environment relative to that in Mn(II)-CF{sub 1} were evident; the local relaxation rate maxima were more pronounced and shifted to higher field strengths, and the relaxation rate per bound Mn(II) increased at all field strengths. Analysis of the data revealed that the number of exchangeable water molecules liganded to bound Mn(II) increased from one in the binary Mn(II)-CF{sub 1} complex to three and two in the ternary Mn(II)-ADP-CF{sub 1} and Mn(II)-ATP-CF{sub 1} complexes, respectively; these results suggest that a water ligand to bound Mn(II) in the Mn(II)-ADP-CF{sub 1} complex is replaced by the {gamma}-phosphate of ATP in the Mn(II)-ATP-CF{sub 1} complex. A binding model is presented to account for these observations.

  5. 75 FR 31321 - Fisheries of the Exclusive Economic Zone Off Alaska; Rock Sole, Flathead Sole, and “Other...

    Science.gov (United States)

    2010-06-03

    .... 0910131363-0087-02] RIN 0648-XW74 Fisheries of the Exclusive Economic Zone Off Alaska; Rock Sole, Flathead... participating in the Amendment 80 limited access fishery in the Bering Sea and Aleutian Islands management area... the trawl rock sole, flathead sole, and ``other flatfish'' fishery category by vessels participating...

  6. TEACHING NEUROMUSCULAR RELAXATION.

    Science.gov (United States)

    NORRIS, JEANNE E.; STEINHAUS, ARTHUR H.

    THIS STUDY ATTEMPTED TO FIND OUT WHETHER (1) THE METHODS FOR ATTAINING NEUROMUSCULAR RELAXATION THAT HAVE PROVED FRUITFUL IN THE ONE-TO-ONE RELATIONSHIP OF THE CLINIC CAN BE SUCCESSFULLY ADAPTED TO THE TEACHER-CLASS RELATIONSHIP OF THE CLASSROOM AND GYMNASIUM, AND (2) NEUROMUSCULAR RELAXATION CAN BE TAUGHT SUCCESSFULLY BY AN APPROPRIATELY TRAINED…

  7. Relaxation of Anisotropic Glasses

    DEFF Research Database (Denmark)

    Deubener, Joachim; Martin, Birgit; Wondraczek, Lothar

    2004-01-01

    . When the load was removed at room temperature a permanent optical anisotropy (birefringence) was observed only perpendicular to cylinder axis and the pressure direction indicating complete elimination of thermal stresses. Relaxation of structural anisotropy was studied from reheating experiments using...... the energy release, thermo-mechanical and optical relaxation behaviour are drawn....

  8. Relaxation techniques for stress

    Science.gov (United States)

    ... raise your heart rate. This is called the stress response. Relaxation techniques can help your body relax and lower your blood pressure ... also many other types of breathing techniques you can learn. In many cases, you do not need much ... including those that cause stress. Meditation has been practiced for thousands of years, ...

  9. Collisional relaxation of electron tail distribution

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru; Okamoto, Masao.

    1985-05-01

    Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

  10. Mechanisms behind the relaxing effect of furosemide on the isolated rabbit ear artery

    Energy Technology Data Exchange (ETDEWEB)

    Tian, R.; Aalkjaer, C.; Andreasen, F. (Institute of Pharmacology, University of Aarhus, Aarhus (Denmark))

    1991-01-01

    The effect of furosemide on isometric contration and {sup 86}Rb uptake were studied in the isolated rabbit central ear artery (CEA). A concentration-dependent relaxing effect of furosemide (0.06 mM-1.0 mM) was found in vessel segments with intact endothelium. The maximal relaxation was 28.6+-3.9% (10). The effect was not diminished in segments deprived of endothelium, and removal of endothelium itself caused no change of the force development to electrical field stimualtion. The relaxing effect was time-dependent and stimulation-dependent and was not significantly affected by membrane depolarization induced by increasing external (K{sup +}) from 10 to 120 mM. The {sup 86}Rb uptake was inhibited by both furosemide and ouabain (8.0+-0.5(8) and 5.3+-0.5(8) versus 12.8+-0.9(16) nmol (K{sup +})x mm{sup -1}x(10 min.){sup -1} in the furosemide (1.0 mM), ouabain (1.0 mM) and control groups, respectively) without interaction between the two drugs. The {sup 86}Rb uptake was not further inhibited by increasing the furosemide concentration from 0.12 mM to 1.0 mM. Our results suggest: firstly, the direct relaxing effect of furosemide on isolated vessel segments in endothelium-independent and secondly, the inhibition of the Na{sup +}-K{sup +}-Cl{sup -} cotransport and a possible consequent hyperpolarization of the membrane is unlikely to be the sole mechanism responsible for the vasorelaxant effect of furosemide. The demonstrated direct effect on vascular tone may be of clinical importance in situations with very high plasma concentrations of the drug or very low concentrations of serum albumin. (aluthor).

  11. Strengthening and stress relaxation of Opalinus Clay

    International Nuclear Information System (INIS)

    Schulze, Otto

    2010-01-01

    Document available in extended abstract form only. Full text follows: In the framework of the EU-project NF-PRO (e.g. RTDC-5, Synthesis Report, D-No 5.2.3), special emphasis was put on the investigation and modelling of near-field processes in a candidate host rock: http://project.nf-pro.org/workspaces/rtdc5/deliverables/d5_2_3_rtdc_5_synthesis_report_final_version. The coupled TMHC-processes under consideration mainly concern the interaction between the host rock in and near to the EDZ and the waste products in its immediate vicinity. With respect to long-term safety analyses, there is no doubt that a sound process understanding is required. However, safe disposal also requires a suitable multi-barrier-system. This has to consist of technical and geo-technical barriers (e.g. container and backfill) but also of a strong geological barrier. Comparing the self-sealing capacity of the candidate host rocks, i.e. salt, clay and crystalline rock formations, where underground rooms will be inevitably backfilled only in part for technical reasons, in a salt formation convergence by viscous deformation provokes the re-establishing of a tight system, whereas in a crystalline rock formation long-term isolation has to be guaranteed solely by the technical and geotechnical components. This work is concentrated on the question, whether convergence and reduction of open space by long-term creep will take place also in a clay-stone formation, where laboratory investigation on Opalinus Clay from the Mont Terri Rock Laboratory was performed for this purpose. Several results from the work on the long-term deformation behaviour of clay-stone exist already. Nevertheless, to the author's knowledge the sound proof of a time-dependent and non-dilatant viscous deformation in the undisturbed far-field of clay-stone is still missing. Results from the rock laboratory at the Mt. Terri site yield hints for an anisotropic state of in-situ stresses, which may continue to exist in the

  12. Strain relaxation during solid-phase epitaxial crystallisation of Ge{sub x}Si{sub 1-x} alloy layers with depth dependent G{sub e} compositions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Wahchung; Elliman, R G; Kringhoj, P [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1994-12-31

    The solid-phase epitaxial crystallisation of depth dependent Ge{sub x}Si{sub lx} alloy layers produced by implanting Ge into Si substrates was studied. In-situ monitoring was done using time-resolved reflectivity (TRR) whilst post-anneal defect structures were characterised by Rutherford backscattering and channeling spectrometry (RBS-C) and transmission electron microscopy (TEM). Particular attention was directed at Ge concentrations above the critical concentration for the growth of fully strained layers. Strain relief is shown to be correlated with a sudden reduction in crystallisation velocity caused by roughening of the crystalline/amorphous interface. 11 refs., 1 tab., 2 figs.

  13. Strain relaxation during solid-phase epitaxial crystallisation of Ge{sub x}Si{sub 1-x} alloy layers with depth dependent G{sub e} compositions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Wahchung; Elliman, R.G.; Kringhoj, P. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1993-12-31

    The solid-phase epitaxial crystallisation of depth dependent Ge{sub x}Si{sub lx} alloy layers produced by implanting Ge into Si substrates was studied. In-situ monitoring was done using time-resolved reflectivity (TRR) whilst post-anneal defect structures were characterised by Rutherford backscattering and channeling spectrometry (RBS-C) and transmission electron microscopy (TEM). Particular attention was directed at Ge concentrations above the critical concentration for the growth of fully strained layers. Strain relief is shown to be correlated with a sudden reduction in crystallisation velocity caused by roughening of the crystalline/amorphous interface. 11 refs., 1 tab., 2 figs.

  14. From field to health: a simple way to increase the nutraceutical content of grape as shown by NO-dependent vascular relaxation.

    Science.gov (United States)

    Fumagalli, Francesca; Rossoni, Mara; Iriti, Marcello; di Gennaro, Antonio; Faoro, Franco; Borroni, Emanuele; Borgo, Michele; Scienza, Attilio; Sala, Angelo; Folco, Giancarlo

    2006-07-26

    Polyphenolic grapevine components involved in plant resistance against pathogens possess various pharmacological properties that include nitric oxide (NO)-dependent vasodilation and anti-inflammatory and free radical scavenging activities, which may explain the protective effect of moderate red wine consumption against cardiovascular disease. The aim of this work was (a) to verify the possibility that preharvest treatments of grapevine with a plant activator, benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), could lead to an enriched nutraceutical potential of wine and (b) to characterize the profile of metabolites responsible for pharmacological activity. Plant spraying at the end of veraison, with a water suspension of BTH (0.3 mM), led to increased whole anthocyanin content as confirmed by HPLC comparative analysis. Extracts from berry skins of BTH-treated grapevines caused NO-dependent vasorelaxation, with a concentration-response curve that was significantly shifted to the left of the control non-BTH-treated curve. Moreover, 1:1000 dilutions of berry extracts from BTH-treated plants significantly increased basal production of guanosine 3',5'-cyclic monophosphate (cGMP) in human vascular endothelial cells when compared to the corresponding extracts of untreated plants. These results show that BTH treatment increases anthocyanin content of grape extracts, as well as their ability to induce NO-mediated vasoprotection. No increase of anthocyanin content was observed in the wine extracts from BTH-treated vines. It is concluded that BTH treatment could be exploited to increase the nutraceutical potential of grapes.

  15. Abrupt relaxation in high-spin molecules

    International Nuclear Information System (INIS)

    Chang, C.-R.; Cheng, T.C.

    2000-01-01

    Mean-field model suggests that the rate of resonant quantum tunneling in high-spin molecules is not only field-dependent but also time-dependent. The relaxation-assisted resonant tunneling in high-spin molecules produces an abrupt magnetization change during relaxation. When the applied field is very close to the resonant field, a time-dependent interaction field gradually shifts the energies of different collective spin states, and magnetization tunneling is observed as two energies of the spin states coincide

  16. Sole Mothers in Australia: Supporting Mothers to Seek Work

    OpenAIRE

    Marilyn McHugh; Jane Millar

    1996-01-01

    The rapid increase in the numbers of sole parents in Australia - and their high risk of poverty - has meant that these families have become a focus of increasing concern. This paper explores the issue of sole motherhood and employment, with a particular emphasis on examining the relationship between social security policies and current discourses on the role of women in Australian society, including the perspectives of sole mothers themselves. The paper is part of an edited collection (Duncan...

  17. Tax Policy and Sole Proprietorships: A Closer Look

    OpenAIRE

    Nelson, Susan C.

    2008-01-01

    The 21 million sole proprietorship returns filed in 2005 represent a wide variety of economic activity. This paper examines three major tax policy issues related to sole proprietorships—taxpayer compliance, taxpayer burden, and incentives for growth. It uses tax return data to take a closer look at sole proprietorships. It proposes a new taxonomy for describing these returns in an economically meaningful way, based on the principal factors of production that they use: their own labor, hired l...

  18. Interstitial relaxations due to hydrostatic stress in niobium--oxygen alloys

    International Nuclear Information System (INIS)

    Tewari, S.N.

    1974-01-01

    Experimental investigations of the anelastic relaxation induced by hydrostatic stress in the range from ambient to 81 ksi were made for niobium--oxygen alloys. The anelastic responses, both for the pressurization and the pressure release experiments, were followed by measuring the relative length change between the oxygenated niobium sample and a pure niobium frame with a precision of about 2 A. The relaxation spectrum observed was shown to be made up of three distinct relaxations with unique relaxation times and strengths. The pressure dependence of the relaxation times gave the apparent activation volume for these relaxations of the order of 4 cm 3 /mole. The relaxations were observed to have relaxation strengths of the order of 10 -4 which were found to be independent of pressure up to 81 ksi. The relaxation times for these relaxations were found to occur in the same general temperature range as those for the Snoek relaxations of oxygen clusters in niobium. The temperature dependence of the relaxation times, however, gave activation energies of about 11 to 15 kcal/mole, as compared with roughly 27 to 29 kcal/mole for the Snoek relaxation of oxygen clusters in niobium. Several possible models for these relaxations were developed, however, none could predict the observed temperature dependence. The best interpretation of the data is that due to some anomalous competing relaxation the actual temperature dependence of these relaxations could not be observed. A completely self-consistent analysis is found which is based upon this assumption. (U.S.)

  19. Relaxed plasma-vacuum systems

    International Nuclear Information System (INIS)

    Spies, G.O.; Lortz, D.; Kaiser, R.

    2001-01-01

    Taylor's theory of relaxed toroidal plasmas (states of lowest energy with fixed total magnetic helicity) is extended to include a vacuum between the plasma and the wall. In the extended variational problem, one prescribes, in addition to the helicity and the magnetic fluxes whose conservation follows from the perfect conductivity of the wall, the fluxes whose conservation follows from the assumption that the plasma-vacuum interface is also perfectly conducting (if the wall is a magnetic surface, then one has the toroidal and the poloidal flux in the vacuum). Vanishing of the first energy variation implies a pressureless free-boundary magnetohydrostatic equilibrium with a Beltrami magnetic field in the plasma, and in general with a surface current in the interface. Positivity of the second variation implies that the equilibrium is stable according to ideal magnetohydrodynamics, that it is a relaxed state according to Taylor's theory if the interface is replaced by a wall, and that the surface current is nonzero (at least if there are no closed magnetic field lines in the interface). The plane slab, with suitable boundary conditions to simulate a genuine torus, is investigated in detail. The relaxed state has the same double symmetry as the vessel if, and only if, the prescribed helicity is in an interval that depends on the prescribed fluxes. This interval is determined in the limit of a thin slab

  20. Relaxation strain measurements in cellular dislocation structures

    International Nuclear Information System (INIS)

    Tsai, C.Y.; Quesnel, D.J.

    1984-01-01

    The conventional picture of what happens during a stress relaxation usually involves imagining the response of a single dislocation to a steadily decreasing stress. The velocity of this dislocation decreases with decreasing stress in such a way that we can measure the stress dependence of the dislocation velocity. Analysis of the data from a different viewpoint enables us to calculate the apparent activation volume for the motion of the dislocation under the assumption of thermally activated glie. Conventional thinking about stress relaxation, however, does not consider the eventual fate of this dislocation. If the stress relaxes to a low enough level, it is clear that the dislocation must stop. This is consistent with the idea that we can determine the stress dependence of the dislocation velocity from relaxation data only for those cases where the dislocation's velocity is allowed to approach zero asymptotically, in short, for those cases where the dislocation never stops. This conflict poses a dilemma for the experimentalist. In real crystals, however, obstacles impede the dislocation's progress so that those dislocations which are stopped at a given stress will probably never resume motion under the influence of the steadily declining stress present during relaxation. Thus one could envision stress relaxation as a process of exhaustion of mobile dislocations, rather than a process of decreasing dislocation velocity. Clearly both points of view have merit and in reality both mechanisms contribute to the phenomena

  1. The relaxation of plasmas with dust particles

    International Nuclear Information System (INIS)

    Chutov, Yu.I.; Kravchenko, A.Yu.; Schram, P.P.J.M.

    1997-01-01

    Various parameters of relaxing plasmas with dust particles including the electron and ion energy distributions function are numerically simulated at various parameters of the dust particles using the PIC method and taking into account the dynamics of the dust particle charge without the assumption about the equilibrium of electrons and ions. Coulomb collisions are taken into account in the framework of the method of stochastic differential equations. The relaxation of bounded plasma clouds expanding into a vacuum as well as the relaxation of a uniform plasma, in which dust particles appear at some initial time, are investigated. The obtained results show that the relaxation of plasmas can be accompanied by a deviation of the ion distribution function from equilibrium as well as a change of the mean energy of electrons and ions because of the dependence of the collection of electrons and ions by dust particles on their energy. (author)

  2. Discards monitoring in the gillnet fishery for sole

    NARCIS (Netherlands)

    Uhlmann, S.S.

    2014-01-01

    Approximately 2-3% of the Dutch fishing quota for sole (Solea solea) is caught by a 60-vessel strong inshore fleet of gillnetters. From their home ports in IJmuiden, Scheveningen and Den Helder, these vessels fish typically with bottom-set gillnets for sole during 1 day trips between March and

  3. 31 CFR 515.546 - Accounts of Cuban sole proprietorships.

    Science.gov (United States)

    2010-07-01

    ... proprietorships. Specific licenses are issued unblocking sole proprietorships established under the laws of Cuba... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Accounts of Cuban sole proprietorships. 515.546 Section 515.546 Money and Finance: Treasury Regulations Relating to Money and Finance...

  4. Relaxation of synchronization on complex networks.

    Science.gov (United States)

    Son, Seung-Woo; Jeong, Hawoong; Hong, Hyunsuk

    2008-07-01

    We study collective synchronization in a large number of coupled oscillators on various complex networks. In particular, we focus on the relaxation dynamics of the synchronization, which is important from the viewpoint of information transfer or the dynamics of system recovery from a perturbation. We measure the relaxation time tau that is required to establish global synchronization by varying the structural properties of the networks. It is found that the relaxation time in a strong-coupling regime (K>Kc) logarithmically increases with network size N , which is attributed to the initial random phase fluctuation given by O(N-1/2) . After elimination of the initial-phase fluctuation, the relaxation time is found to be independent of the system size; this implies that the local interaction that depends on the structural connectivity is irrelevant in the relaxation dynamics of the synchronization in the strong-coupling regime. The relaxation dynamics is analytically derived in a form independent of the system size, and it exhibits good consistency with numerical simulations. As an application, we also explore the recovery dynamics of the oscillators when perturbations enter the system.

  5. Stress relaxation in viscous soft spheres.

    Science.gov (United States)

    Boschan, Julia; Vasudevan, Siddarth A; Boukany, Pouyan E; Somfai, Ellák; Tighe, Brian P

    2017-10-04

    We report the results of molecular dynamics simulations of stress relaxation tests in athermal viscous soft sphere packings close to their unjamming transition. By systematically and simultaneously varying both the amplitude of the applied strain step and the pressure of the initial condition, we access both linear and nonlinear response regimes and control the distance to jamming. Stress relaxation in viscoelastic solids is characterized by a relaxation time τ* that separates short time scales, where viscous loss is substantial, from long time scales, where elastic storage dominates and the response is essentially quasistatic. We identify two distinct plateaus in the strain dependence of the relaxation time, one each in the linear and nonlinear regimes. The height of both plateaus scales as an inverse power law with the distance to jamming. By probing the time evolution of particle velocities during relaxation, we further identify a correlation between mechanical relaxation in the bulk and the degree of non-affinity in the particle velocities on the micro scale.

  6. COMPARATIVE ASSESSMENT OF NUCLEAR MAGNETIC RELAXATION CHARACTERISTICS OF SUNFLOWER AND RAPESEED LECITHIN

    OpenAIRE

    Lisovaya E. V.; Victorova E. P.; Agafonov O. S.; Kornen N. N.; Shahray T. A.

    2015-01-01

    The article presents a comparative assessment and peculiarities of nuclear magnetic relaxation characteristics of rapeseed and sunflower lecithin. It was established, that lecithin’s nuclear magnetic relaxation characteristics, namely, protons’ spin-spin relaxation time and amplitudes of nuclear magnetic relaxation signals of lecithin components, depend on content of oil’s fat acids and phospholipids, contained in the lecithin. Comparative assessment of protons’ spin-spin relaxation time of r...

  7. Muon spin relaxation in ferromagnets. Pt. 1

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Karlsson, E.B.

    1991-04-01

    Expressions for the dipolar and hyperfine contributions to the relaxation rate of muons implanted in a ferromagnet are presented and analysed using the Heisenberg model of spin-waves including dipolar and Zeeman energies. Calculations for EuO indicate that relaxation is likely to be dominated by the hyperfine mechanism, even if the ratio of the hyperfine and dipolar coupling constants is small. The hyperfine mechanism is sensitive to the dipolar energy of the atomic spins, whereas the dipolar mechanisms depend essentially on the exchange energy. For both mechanisms there is an almost quadratic dependence on temperature, throughout much of the ordered magnetic phase, which reflects two-spin-wave difference events from the Raman-type relaxation processes. (author)

  8. Temperature dependence of the hydrated electron's excited-state relaxation. I. Simulation predictions of resonance Raman and pump-probe transient absorption spectra of cavity and non-cavity models

    Science.gov (United States)

    Zho, Chen-Chen; Farr, Erik P.; Glover, William J.; Schwartz, Benjamin J.

    2017-08-01

    We use one-electron non-adiabatic mixed quantum/classical simulations to explore the temperature dependence of both the ground-state structure and the excited-state relaxation dynamics of the hydrated electron. We compare the results for both the traditional cavity picture and a more recent non-cavity model of the hydrated electron and make definite predictions for distinguishing between the different possible structural models in future experiments. We find that the traditional cavity model shows no temperature-dependent change in structure at constant density, leading to a predicted resonance Raman spectrum that is essentially temperature-independent. In contrast, the non-cavity model predicts a blue-shift in the hydrated electron's resonance Raman O-H stretch with increasing temperature. The lack of a temperature-dependent ground-state structural change of the cavity model also leads to a prediction of little change with temperature of both the excited-state lifetime and hot ground-state cooling time of the hydrated electron following photoexcitation. This is in sharp contrast to the predictions of the non-cavity model, where both the excited-state lifetime and hot ground-state cooling time are expected to decrease significantly with increasing temperature. These simulation-based predictions should be directly testable by the results of future time-resolved photoelectron spectroscopy experiments. Finally, the temperature-dependent differences in predicted excited-state lifetime and hot ground-state cooling time of the two models also lead to different predicted pump-probe transient absorption spectroscopy of the hydrated electron as a function of temperature. We perform such experiments and describe them in Paper II [E. P. Farr et al., J. Chem. Phys. 147, 074504 (2017)], and find changes in the excited-state lifetime and hot ground-state cooling time with temperature that match well with the predictions of the non-cavity model. In particular, the experiments

  9. EDITORIAL: `Il sole - no si move'

    Science.gov (United States)

    Kibble, Bob

    1999-05-01

    The Sun may not have moved for Galileo but it is certain that this coming August the Sun will have moved millions of folk towards a thin strip of land about 100 km wide stretching from Cornwall to the Indian Ocean. If you have yet to book your place for the biggest live show of this millennium year there are still places in hotels and campsites. The April edition of the UK camping and caravaning club magazine included at least four sites in Cornwall alone with vacancies. I am told that the difference between seeing a 98% eclipse and totality is considerably greater than 2%. The message appears to be - try to get to the line. However, a popular misconception among lay folk seems to be that you will only be able to see the event in Cornwall. As you will read in this issue the partial event will be visible from virtually the whole of Europe. Anyone who has tried to holiday in Cornwall or Devon will tell you how congested the roads become in any ordinary August. The best advice for this year is either to travel to the south west by bicycle or attack the totality path as it crosses Europe. Access will be much easier. For my part I have booked a hotel in Trier, Germany, about 20 km north of the totality path. An early breakfast on the 11th should leave enough time to motorcycle down to see the shadow. Of course, the whole business is weather dependent. With the chance of a clear sky in Cornwall, Devon and most of western Europe being about 50% on the date in question, forward planning depends on whether you are a `half empty' or a `half full' person. It is worth keeping this fact in mind especially if you drag an expectant family hundreds of miles through traffic just to watch the clouds drift by. Take a colouring book and a board game just in case. Of course, the chance of a clear sky increases to about 90% across Turkey but there are reasons why such a trip might not be so wise in the current political climate. In this special issue readers will find plenty to interest

  10. A NEW DESIGN METHOD FOR FLAT FOOTWEAR SOLES

    Directory of Open Access Journals (Sweden)

    IONESCU Cozmin

    2016-05-01

    Full Text Available Carried research regarding footwear soles reveald that by moulding footwear details can be obtained in a wide variety of models. Shoe soles are complex three dimensional objects and for attaching them with the uppers, the interor countour of the soles has to correspond to the featherline contour of the last. That’s why, is necessary that soles design to be done with high accuracy and in strict accordance to the last. Nowadays, there are specialized software applications which can perform various computer aided design processes for footwear. Among the high performance systems used for the design of footwear soles and injection moulds for shoe soles, we may mention: Delcam Shoe Solution, Delcam PowerSHAPE-e, Padsy II and Padsy III, Shoe Master System, Lectra System, Parmel System and ATOS II System. This paper presents a 3D design method, developed by the authors, for footwear flat soles using PowerSHAPE-e software programm from of Delcam Crispin. The computer-aided design technique used in this paper highlights several important advantages that include: increased design quality; three dimensional viewing of soles, which can lead to immediate decisions, regarding the acceptance of newly developed models; it can be appreciated the complexity of mould cavities execution, without the need of making prototypes; the outlines of construction templates are accurately obtained for the mould cavities and for all size numbers; calculations can easily be done for determining the soles volume for the entire size number, with implications on estimating polymer blend consumption and so on.

  11. Relaxed Binaural LCMV Beamforming

    NARCIS (Netherlands)

    Koutrouvelis, A.; Hendriks, R.C.; Heusdens, R.; Jensen, Jesper Rindom

    2017-01-01

    In this paper, we propose a new binaural beamforming technique, which can be seen as a relaxation of the linearly constrained minimum variance (LCMV) framework. The proposed method can achieve simultaneous noise reduction and exact binaural cue preservation of the target source, similar to the

  12. Structural relaxation monitored by instantaneous shear modulus

    DEFF Research Database (Denmark)

    Olsen, Niels Boye; Dyre, Jeppe; Christensen, Tage Emil

    1998-01-01

    time definition based on a recently proposed expression for the relaxation time, where G [infinity] reflects the fictive temperature. All parameters entering the reduced time were determined from independent measurements of the frequency-dependent shear modulus of the equilibrium liquid....

  13. MORPHOMETRIC EVIDENCE FOR NUTRITIONAL STRESS IN ENGLISH SOLE

    Science.gov (United States)

    We present an application of the powerful thin plate spline method of morphometric analysis to demonstrate its utility for detecting environmental stress in an estuarine flatfish. Juvenile English sole (Pleuronectes vetulus) were captured from Yaquina Bay, Oregon, photographed w...

  14. Disorders presenting with headache as the sole symptom ...

    African Journals Online (AJOL)

    Disorders presenting with headache as the sole symptom. ... Log in or Register to get access to full text downloads. ... probably do not require sophisticated neurological skills or investigations, failure to recognise an underlying disorder or an ...

  15. Basal Cell Carcinoma on the Sole: An Easily Missed Cancer

    Directory of Open Access Journals (Sweden)

    Natalie L. Hone

    2016-10-01

    Full Text Available Basal cell carcinoma (BCC is the most common skin cancer, and solar ultraviolet ray exposure is the most significant risk factor for its development. The plantar foot is infrequently exposed to the sun, thus the presence of BCC on the sole is rare. We report a case of BCC on the sole of the foot and its treatment in the hope to facilitate its detection.

  16. Barriers to Maori sole mothers’ primary health care access

    Directory of Open Access Journals (Sweden)

    Lee R

    2013-12-01

    Full Text Available INTRODUCTION: International research consistently shows that sole mothers experience poorer health and suboptimal health care access. New Zealand studies on sole mothers' health report similar findings. The aim of this exploratory research was to better understand the experiences of Maori sole mothers' access to health services, particularly primary health care, for personal health needs. METHODS: This qualitative study employed a general inductive design informed by a Kaupapa Maori approach, providing guidance on appropriate cultural protocols for recruiting and engaging Maori participants. Distributing written information and snowballing techniques were used to purposively recruit seven Maori sole mothers. Data collection involved semi-structured interviews which were digitally recorded and transcribed verbatim. Data were analysed using general inductive thematic analysis to identify commonalities and patterns in participants' experiences. FINDINGS: The dominant themes that emerged captured and described participants' experiences in accessing health care. The major barrier to access reported was cost. Compounding cost, transport difficulties and location or scheduling of services were additional barriers to health service accessibility. Child-related issues also posed a barrier, including prioritising children's needs and childcare over personal health needs. CONCLUSION: The findings illuminate Maori sole mothers' experiences of accessing health care and the complex socioeconomic inequalities affecting access options and uptake of services. Further investigation of barriers to access is needed. The study has implications for addressing barriers to access at policy, funding and practice levels to improve health outcomes and equitable health care access for Maori sole mothers.

  17. Spin relaxation of iron in mixed state hemoproteins

    International Nuclear Information System (INIS)

    Wajnberg, E.; Kalinowski, H.J.; Bemski, G.; Helman, J.S.

    1984-01-01

    In pure states hemoproteins the relaxation of iron depends on its spin state. It is found that in both mixed state met-hemoglobin and met-myoglobin, the low and high spin states relax through an Orbach-like process. Also, very short (approx. 1 ns) and temperature independent transverse relaxation times T 2 were estimated. This peculiar behaviour of the relaxation may result from the unusual electronic structure of mixed state hemoproteins that allows thermal equilibrium and interconversion of the spin states. (Author) [pt

  18. Hyperfine relaxation of an optically pumped cesium vapor

    International Nuclear Information System (INIS)

    Tornos, J.; Amare, J.C.

    1986-01-01

    The relaxation of hyperfine orientation indirectly induced by optical pumping with a σ-polarized D 1 -light in a cesium vapor in the presence of Ar is experimentally studied. The detection technique ensures the absence of quadrupole relaxation contributions in the relaxation signals. The results from the dependences of the hyperfine relaxation rate on the temperature and argon pressure are: diffusion coefficient of Cs in Ar, D 0 = 0.101 +- 0.010 cm 2 s -1 at 0 0 C and 760 Torr; relaxation cross section by Cs-Ar collisions, σ/sub c/ = (104 +- 5) x 10 -23 cm 2 ; relaxation cross section by Cs-Cs (spin exchange) collisions, σ/sub e//sub x/ = (1.63 +- 0.13) x 10 -14 cm 2

  19. Cross-relaxation in multiple pulse NQR spin-locking

    Energy Technology Data Exchange (ETDEWEB)

    Beltjukov, P. A.; Kibrik, G. E. [Perm State University, Physics Department (Russian Federation); Furman, G. B., E-mail: gregoryf@bgu.ac.il; Goren, S. D. [Ben Gurion University, Physics Department (Israel)

    2008-01-15

    The experimental and theoretical NQR multiple-pulse spin locking study of cross-relaxation process in solids containing nuclei of two different sorts I > 1/2 and S = 1/2 coupled by the dipole-dipole interactions and influenced by an external magnetic field. Two coupled equations for the inverse spin temperatures of the both spin systems describing the mutual spin lattice relaxation and the cross-relaxation were obtained using the method of the nonequilibrium state operator. It is shown that the relaxation process is realized with non-exponential time dependence describing by a sum of two exponents. The cross relaxation time is calculated as a function of the multiple-pulse field parameters which agree with the experimental data. The calculated magnetization cross relaxation time vs the strength of the applied magnetic field agrees well with the obtained experimental data.

  20. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  1. Produtividade da beterraba e rúcula em função da época de plantio em monocultivo e consórcio Yield of sugar beet and rocket depending on planting times in sole crop and intercropping system

    Directory of Open Access Journals (Sweden)

    Leilson C Grangeiro

    2007-12-01

    Full Text Available Avaliou-se os rendimentos das culturas da beterraba e da rúcula em função de épocas de plantio e sistemas solteiro e consorciado, em Mossoró, de janeiro a março de 2005. O delineamento experimental utilizado foi de blocos casualizados com nove tratamentos em quatro repetições. Os tratamentos consistiram dos consórcios da beterraba com rúcula estabelecidos aos 0, 7, 14 e 21 dias após a semeadura da beterraba, monocultura da beterraba e as monoculturas da rúcula, nas mesmas épocas de estabelecimento dos cultivos consorciados. A semeadura da rúcula e beterraba realizada na mesma época proporcionaram maior massa fresca e seca da parte aérea e produtividade de rúcula, sendo respectivamente, de 50,19 g/planta; 5,86 g/planta e 1338,47 g/m². Já para a beterraba, independentemente da época de semeadura, o monocultivo foi superior ao consórcio na produção de massa fresca e de raízes. Os maiores índices de uso eficiente da terra foram obtidos no sistema de consórcio quando a semeadura da rúcula foi realizada no mesmo período (2,0 e aos sete dias (1,9 após a semeadura da beterraba.The yield of sugar beet and rocket was evaluated, as a result of planting times in sole crop and intercropping system. The experiment was carried out in Mossoró, from January to March,f 2005. The experimental design was of randomized complete blocks with nine treatments and four replications. The treatments consisted of the intercrops of sugar beet with rocket established at 0, 7, 14 and 21 days after sugar beet sowing date, as well as of sugar beet and rocket cultivated as sole crops, planted at the same times of the intercropping establishment. The highest values of fresh shoot (50.19 g/plant, dry mass (5.86 g/plant and yield (1338.47 g/m² of rocket were observed in the intercropping systems established at the same time. The highest values of shoot fresh mass and root yield of sugar beet were observed in sole crop. The highest land equivalent

  2. Statistical mechanics of violent relaxation

    International Nuclear Information System (INIS)

    Shu, F.H.

    1978-01-01

    We reexamine the foundations of Lynden-Bell's statistical mechanical discussion of violent relaxation in collisionless stellar systems. We argue that Lynden-Bell's formulation in terms of a continuum description introduces unnecessary complications, and we consider a more conventional formulation in terms of particles. We then find the exclusion principle discovered by Lynden-Bell to be quantitatively important only at phase densities where two-body encounters are no longer negligible. Since the edynamical basis for the exclusion principle vanishes in such cases anyway, Lynden-Bell statistics always reduces in practice to Maxwell-Boltzmann statistics when applied to stellar systems. Lynden-Bell also found the equilibrium distribution function generally to be a sum of Maxwellians with velocity dispersions dependent on the phase density at star formation. We show that this difficulty vanishes in the particulate description for an encounterless stellar system as long as stars of different masses are initially well mixed in phase space. Our methods also demonstrate the equivalence between Gibbs's formalism which uses the microcanonical ensemble and Boltzmann's formalism which uses a coarse-grained continuum description. In addition, we clarify the concept of irreversible behavior on a macroscopic scale for an encounterless stellar system. Finally, we comment on the use of unusual macroscopic constraints to simulate the effects of incomplete relaxation

  3. Experiments in paramagnetic relaxation

    International Nuclear Information System (INIS)

    Lijphart, E.E.

    1976-01-01

    This thesis presents two attempts to improve the resolving power of the relaxation measurement technique. The first attempt reconsiders the old technique of steady state saturation. When used in conjunction with the pulse technique, it offers the possibility of obtaining additional information about the system in which all-time derivatives are zero; in addition, non-linear effects may be distinguished from each other. The second attempt involved a systematic study of only one system: Cu in the Tutton salts (K and Rb). The systematic approach, the high accuracy of the measurement and the sheer amount of experimental data for varying temperature, magnetic field and concentration made it possible in this case to separate the prevailing relaxation mechanisms reliably

  4. Relaxation from particle production

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Marques-Tavares, Gustavo [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States)

    2016-12-20

    We consider using particle production as a friction force by which to implement a “Relaxion” solution to the electroweak hierarchy problem. Using this approach, we are able to avoid superplanckian field excursions and avoid any conflict with the strong CP problem. The relaxation mechanism can work before, during or after inflation allowing for inflationary dynamics to play an important role or to be completely decoupled.

  5. Excited-state relaxation of some aminoquinolines

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants ( k f of 2-amino-3-( 2 ′ -benzoxazolylquinoline (I, 2-amino-3-( 2 ′ -benzothiazolylquinoline (II, 2-amino-3-( 2 ′ -methoxybenzothiazolyl-quinoline (III, 2-amino-3-( 2 ′ -benzothiazolylbenzoquinoline (IV at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol as the temperature decreases (the solvent viscosity increases points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant k f (up to about 7 times as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.

  6. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro

    2006-01-01

    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  7. Stiffness Effects in Rocker-Soled Shoes: Biomechanical Implications

    Science.gov (United States)

    Su, Pei-Fang; Chung, Chia-Hua; Hsia, Chi-Chun; Chang, Chih-Han

    2017-01-01

    Rocker-soled shoes provide a way to reduce the possible concentration of stress, as well as change movement patterns, during gait. This study attempts to examine how plantar force and spatio-temporal variables are affected by two rocker designs, one with softer and one with denser sole materials, by comparing them with the barefoot condition and with flat-soled shoes. Eleven subjects’ gait parameters during walking and jogging were recorded. Our results showed that compared with barefoot walking, plantar forces were higher for flat shoes while lower for both types of rocker shoes, the softer-material rocker being the lowest. The plantar force of flat shoes is greater than the vertical ground reaction force, while that of both rocker shoes is much less, 13.87–30.55% body weight. However, as locomotion speed increased to jogging, for all shoe types, except at the second peak plantar force of the denser sole material rocker shoes, plantar forces were greater than for bare feet. More interestingly, because the transmission of force was faster while jogging, greater plantar force was seen in the rocker-soled shoes with softer material than with denser material; results for higher-speed shock absorption in rocker-soled shoes with softer material were thus not as good. In general, the rolling phenomena along the bottom surface of the rocker shoes, as well as an increase in the duration of simultaneous curve rolling and ankle rotation, could contribute to the reduction of plantar force for both rocker designs. The possible mechanism is the conversion of vertical kinetic energy into rotational kinetic energy. To conclude, since plantar force is related to foot-ground interface and deceleration methods, rocker-design shoes could achieve desired plantar force reduction through certain rolling phenomena, shoe-sole stiffness levels, and locomotion speeds. PMID:28046009

  8. Stiffness Effects in Rocker-Soled Shoes: Biomechanical Implications.

    Directory of Open Access Journals (Sweden)

    Shih-Yun Lin

    Full Text Available Rocker-soled shoes provide a way to reduce the possible concentration of stress, as well as change movement patterns, during gait. This study attempts to examine how plantar force and spatio-temporal variables are affected by two rocker designs, one with softer and one with denser sole materials, by comparing them with the barefoot condition and with flat-soled shoes. Eleven subjects' gait parameters during walking and jogging were recorded. Our results showed that compared with barefoot walking, plantar forces were higher for flat shoes while lower for both types of rocker shoes, the softer-material rocker being the lowest. The plantar force of flat shoes is greater than the vertical ground reaction force, while that of both rocker shoes is much less, 13.87-30.55% body weight. However, as locomotion speed increased to jogging, for all shoe types, except at the second peak plantar force of the denser sole material rocker shoes, plantar forces were greater than for bare feet. More interestingly, because the transmission of force was faster while jogging, greater plantar force was seen in the rocker-soled shoes with softer material than with denser material; results for higher-speed shock absorption in rocker-soled shoes with softer material were thus not as good. In general, the rolling phenomena along the bottom surface of the rocker shoes, as well as an increase in the duration of simultaneous curve rolling and ankle rotation, could contribute to the reduction of plantar force for both rocker designs. The possible mechanism is the conversion of vertical kinetic energy into rotational kinetic energy. To conclude, since plantar force is related to foot-ground interface and deceleration methods, rocker-design shoes could achieve desired plantar force reduction through certain rolling phenomena, shoe-sole stiffness levels, and locomotion speeds.

  9. Pathogenesis and Treatment of Sole Ulcers and White Line Disease.

    Science.gov (United States)

    Shearer, J K; van Amstel, Sarel R

    2017-07-01

    Sole ulcers and white line disease are 2 of the most common claw horn lesions in confined dairy cattle. Predisposing causes include unbalanced weight bearing, and metabolic, enzymatic, and hormonal changes. The white line serves as the junction between the sole and axial and abaxial wall. It is vulnerable to trauma and separation, permitting organic matter to become entrapped. Colonization contributes to retrograde movement of the infection to the solar and perioplic corium, where an abscess forms resulting in pain and lameness. Successful treatment requires an orthopedic foot block to the healthy claw and corrective trimming of the lesion. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Variational formulation of relaxed and multi-region relaxed magnetohydrodynamics

    Science.gov (United States)

    Dewar, R. L.; Yoshida, Z.; Bhattacharjee, A.; Hudson, S. R.

    2015-12-01

    > Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic reconnection. By contrast, in the Taylor relaxation model for formation of macroscopically self-organized plasma equilibrium states, all these constraints are relaxed save for the global magnetic fluxes and helicity. A Lagrangian variational principle is presented that leads to a new, fully dynamical, relaxed magnetohydrodynamics (RxMHD), such that all static solutions are Taylor states but also allows state with flow. By postulating that some long-lived macroscopic current sheets can act as barriers to relaxation, separating the plasma into multiple relaxation regions, a further generalization, multi-region relaxed magnetohydrodynamics (MRxMHD) is developed.

  11. The dielectric α relaxation at a temperature close to T sub(g)

    International Nuclear Information System (INIS)

    Gomez Ribelles, J.L.; Diaz Calleja, R.

    1985-01-01

    It is shown in this work how the dependence of the mean relaxation times of the dielectric α relaxation on temperature deviates from the Williams, Landel and Ferry model at a temperature close to T sub(g). In some cases, an Arrhenius-like relationship for this relaxation can be observed for temperatures below T sub(g)

  12. Dynamics of relaxed inflation

    Science.gov (United States)

    Tangarife, Walter; Tobioka, Kohsaku; Ubaldi, Lorenzo; Volansky, Tomer

    2018-02-01

    The cosmological relaxation of the electroweak scale has been proposed as a mechanism to address the hierarchy problem of the Standard Model. A field, the relaxion, rolls down its potential and, in doing so, scans the squared mass parameter of the Higgs, relaxing it to a parametrically small value. In this work, we promote the relaxion to an inflaton. We couple it to Abelian gauge bosons, thereby introducing the necessary dissipation mechanism which slows down the field in the last stages. We describe a novel reheating mechanism, which relies on the gauge-boson production leading to strong electro-magnetic fields, and proceeds via the vacuum production of electron-positron pairs through the Schwinger effect. We refer to this mechanism as Schwinger reheating. We discuss the cosmological dynamics of the model and the phenomenological constraints from CMB and other experiments. We find that a cutoff close to the Planck scale may be achieved. In its minimal form, the model does not generate sufficient curvature perturbations and additional ingredients, such as a curvaton field, are needed.

  13. Seasonal incidence of lameness and risk factors associated with thin soles, white line disease, ulcers, and sole punctures in dairy cattle.

    Science.gov (United States)

    Sanders, A H; Shearer, J K; De Vries, A

    2009-07-01

    Lameness is a multifactorial condition with many causes. In this study, cow lifetime records were used to quantify the incidence of specific lameness-causing lesions and investigate factors associated with those lesions. Of primary interest were the effects of seasonality and the effects of thin soles (TS). Thin sole-induced toe ulcers (TSTU) occurring adjacent to the white line in the apical portion of the weight-bearing surface were distinguished from white line disease (WLD) occurring in the region of the abaxial heel sole junction. Sole (SU), heel (HU), and toe (TU) ulcers; TS; sole punctures (SP); leg injuries (INJ); and other (OTH) lesions (e.g., infectious diseases, laminitis, unclassified hemorrhage) were also considered. Data were collected from May 2004 through October 2007 and included records for 4,915 cows of which 1,861 had at least one recorded lameness event. Of these, 20% were TSTU, 20% OTH, 16% SU, 13% TS, 10% WLD, 8% HU, 6% INJ, 4% SP, and 2% TU. Annual incidence risk for lameness was 49.1%. Overall incidence rate for lameness was 1.41/1,000 cow-days, and rates for all lesions were highest in the summer. As parity increased, so did incidence rates for TS, SU, WLD, HU, and INJ. For TS, TSTU, and WLD, incidence rates were lowest in early lactation (16 to 60 DIM), whereas for SU, HU, TU, incidence rates were highest in mid lactation (61 to 150 DIM). Cox proportional hazard models for TS, TSTU, WLD, SU, HU, TU, and SP included age and year of first calving and milk production capacity. Prior/concurrent lameness events, season, parity, and stage of lactation were included as time-dependent effects. Prior/concurrent TS increased the hazard for all other lesions, particularly TSTU, and HU. Having any other prior claw lesion also increased the hazard for all lesions. Hazard was highest in summer for all lesions except TU. Stage of lactation was a significant effect in hazard of TSTU, which was lowest in mid lactation (61 to 150 DIM).

  14. pigmentation of the sole of the foot in rhodesian africans

    African Journals Online (AJOL)

    1971-01-23

    Jan 23, 1971 ... basal layer. (Photo by courtesy of Dr C. M. D. Ross.) Fig. 8. From a biopsy of a grade III area on the sole of the foot a section shows, apart from proliferated melanocytes in the basal layer, isolated pigmented cells extending through the stratum malpighii to the stratum granulosum above it, (Photo by courtesy ...

  15. Deaths among West African dwarf goats fed sole Dactyladaenia barteri

    African Journals Online (AJOL)

    Dactyladaema barteri is an important shrub utilized in fallow development and as a much-preferred ruminant browse by local farmers in Nigeria. We report the death of two 12 – 15 months old West African Dwarf (WAD) goats used in a digestibility trail with D. barteri as sole feed and in a mixed browse - grass diet in the ...

  16. Degloved foot sole successfully reconstructed with split thickness skin grafts

    NARCIS (Netherlands)

    Janssens, Loes; Holtslag, Herman R.; Schellekens, Pascal P A; Leenen, Luke P H

    2015-01-01

    Introduction The current opinion is that split thickness skin grafts are not suitable to reconstruct a degloved foot sole. The tissue is too fragile to carry full bodyweight; and therefore, stress lesions frequently occur. The treatment of choice is the reuse of the avulsed skin whenever possible,

  17. Recognition and Accountability: Sole Parent Postgraduates in University Conditions

    Science.gov (United States)

    Hook, Genine A.

    2015-01-01

    This paper aims to examine some of ways sole parents sought recognition as postgraduate students in Australian universities. Judith Butler's theory of recognition notes that recognition is always partial and any account we give of ourselves must be given to another. Participants articulated that supervisors were critical in the process of…

  18. Folic acid supplementation is not the sole factor in determining ...

    African Journals Online (AJOL)

    Folic acid supplementation is not the sole factor in determining neural tube defects: The possible role of autoantibodies. Keat Wei Loo, Siew Hua Gan. Abstract. Neural tube defects (NTDs) are severe but common congenital malformations. Neonates who suffer from NTDs may experience long-term complications throughout ...

  19. ELECTROCHEMICAL TECHNOLOGIES FOR OBTAINING MOULDS FOR SOLES OF SHOES

    Directory of Open Access Journals (Sweden)

    Cornelia LUCA

    2013-05-01

    Full Text Available The paper presents contributions in the designing of some electrochemical technologiesfor the manufacturing of the moulds used in the footwear soles obtaining. There are presented a fewmethods for the moulds obtaining, using electro-deposit processes. There are presented thetechnological phases of the obtaining process of the electrolytes and electrodes preparing and thetechnological stages of the moulds manufacturing.

  20. Yield Performance of Some Cowpea Varieties under Sole and ...

    African Journals Online (AJOL)

    Nekky Umera

    The mean number of pod/plant, pod weight and seed yield of the cowpea varieties ... pattern of peasant farmers in Nigeria. Some of the advantages ... in maize-pigeon pea intercropping system as compared to sole crops. While intercropping ...

  1. Electron spin-lattice relaxation in fractals

    International Nuclear Information System (INIS)

    Shrivastava, K.N.

    1986-08-01

    We have developed the theory of the spin-fracton interaction for paramagnetic ions in fractal structures. The interaction is exponentially damped by the self-similarity length of the fractal and by the range dimensionality d Φ . The relaxation time of the spin due to the absorption and emission of the fracton has been calculated for a general dimensionality called the Raman dimensionality d R , which for the fractons differs from the Hausdorff (fractal) dimensionality, D, as well as from the Euclidean dimensionality, d. The exponent of the energy level separation in the relaxation rate varies with d R d Φ /D. We have calculated the spin relaxation rate due to a new type of Raman process in which one fracton is absorbed to affect a spin transition from one electronic level to another and later another fracton is emitted along with a spin transition such that the difference in the energies of the two fractons is equal to the electronic energy level separation. The temperature and the dimensionality dependence of such a process has been found in several approximations. In one of the approximations where the van Vleck relaxation rate for a spin in a crystal is known to vary with temperature as T 9 , our calculated variation for fractals turns out to be T 6.6 , whereas the experimental value for Fe 3+ in frozen solutions of myoglobin azide is T 6.3 . Since we used d R =4/3 and the fracton range dimensionality d Φ =D/1.8, we expect to measure the dimensionalities of the problem by measuring the temperature dependence of the relaxation times. We have also calculated the shift of the paramagnetic resonance transition for a spin in a fractal for general dimensionalities. (author)

  2. Relaxation in the XX quantum chain

    International Nuclear Information System (INIS)

    Platini, Thierry; Karevski, Dragi

    2007-01-01

    We present the results obtained on the magnetization relaxation properties of an XX quantum chain in a transverse magnetic field. We first consider an initial thermal kink-like state where half of the chain is initially thermalized at a very high temperature T b while the remaining half, called the system, is put at a lower temperature T s . From this initial state, we derive analytically the Green function associated with the dynamical behaviour of the transverse magnetization. Depending on the strength of the magnetic field and on the temperature of the system, different regimes are obtained for the magnetic relaxation. In particular, with an initial droplet-like state, that is a cold subsystem of the finite size in contact at both ends with an infinite temperature environment, we derive analytically the behaviour of the time-dependent system magnetization

  3. Mechanism of nuclear cross-relaxation in magnetically ordered media

    Energy Technology Data Exchange (ETDEWEB)

    Buishvili, L L; Volzhan, E B; Giorgadze, N P [AN Gruzinskoj SSR, Tbilisi. Inst. Fiziki

    1975-09-01

    A mechanism of two-step nuclear relaxation in magnetic ordered dielectrics is proposed. The case is considered where the energy conservation in the cross relaxation (CR) process is ensured by the lattice itself without spin-spin interactions. Expressions have been obtained describing the temperature dependence of the CR rate. For a nonuniform broadened NMR line it has been shown that the spin-lattice relaxation time for a spin packet taken out from the equilibrium may be determined by the CR time owing to the mechanism suggested. When the quantization axes for electron and nuclear spins coincide, the spin-lattice relaxation is due to the three-magnon mechanism. The cross-relaxation stage has been shown to play a significant role in the range of low temperatures (T<10 deg K) and to become negligible with a temperature increase.

  4. Muon spin relaxation in random spin systems

    International Nuclear Information System (INIS)

    Toshimitsu Yamazaki

    1981-01-01

    The longitudinal relaxation function Gsub(z)(t) of the positive muon can reflect dynamical characters of local field in a unique way even when the correlation time is longer than the Larmor period of local field. This method has been applied to studies of spin dynamics in spin glass systems, revealing sharp but continuous temperature dependence of the correlation time. Its principle and applications are reviewed. (author)

  5. Charge Relaxation Dynamics of an Electrolytic Nanocapacitor

    Science.gov (United States)

    2015-01-01

    Understanding ion relaxation dynamics in overlapping electric double layers (EDLs) is critical for the development of efficient nanotechnology-based electrochemical energy storage, electrochemomechanical energy conversion, and bioelectrochemical sensing devices as well as the controlled synthesis of nanostructured materials. Here, a lattice Boltzmann (LB) method is employed to simulate an electrolytic nanocapacitor subjected to a step potential at t = 0 for various degrees of EDL overlap, solvent viscosities, ratios of cation-to-anion diffusivity, and electrode separations. The use of a novel continuously varying and Galilean-invariant molecular-speed-dependent relaxation time (MSDRT) with the LB equation recovers a correct microscopic description of the molecular-collision phenomena and enhances the stability of the LB algorithm. Results for large EDL overlaps indicated oscillatory behavior for the ionic current density, in contrast to monotonic relaxation to equilibrium for low EDL overlaps. Further, at low solvent viscosities and large EDL overlaps, anomalous plasmalike spatial oscillations of the electric field were observed that appeared to be purely an effect of nanoscale confinement. Employing MSDRT in our simulations enabled modeling of the fundamental physics of the transient charge relaxation dynamics in electrochemical systems operating away from equilibrium wherein Nernst–Einstein relation is known to be violated. PMID:25678941

  6. Communication: Relaxation-limited electronic currents in extended reservoir simulations

    Science.gov (United States)

    Gruss, Daniel; Smolyanitsky, Alex; Zwolak, Michael

    2017-10-01

    Open-system approaches are gaining traction in the simulation of charge transport in nanoscale and molecular electronic devices. In particular, "extended reservoir" simulations, where explicit reservoir degrees of freedom are present, allow for the computation of both real-time and steady-state properties but require relaxation of the extended reservoirs. The strength of this relaxation, γ, influences the conductance, giving rise to a "turnover" behavior analogous to Kramers turnover in chemical reaction rates. We derive explicit, general expressions for the weak and strong relaxation limits. For weak relaxation, the conductance increases linearly with γ and every electronic state of the total explicit system contributes to the electronic current according to its "reduced" weight in the two extended reservoir regions. Essentially, this represents two conductors in series—one at each interface with the implicit reservoirs that provide the relaxation. For strong relaxation, a "dual" expression-one with the same functional form-results, except now proportional to 1/γ and dependent on the system of interest's electronic states, reflecting that the strong relaxation is localizing electrons in the extended reservoirs. Higher order behavior (e.g., γ2 or 1/γ2) can occur when there is a gap in the frequency spectrum. Moreover, inhomogeneity in the frequency spacing can give rise to a pseudo-plateau regime. These findings yield a physically motivated approach to diagnosing numerical simulations and understanding the influence of relaxation, and we examine their occurrence in both simple models and a realistic, fluctuating graphene nanoribbon.

  7. Effectiveness of relaxation techniques before diagnostic screening of cancer patients

    Directory of Open Access Journals (Sweden)

    Montserrat Aiger

    2016-07-01

    Full Text Available Psychophysiological arousal was observed in cancer patients during the application of relaxation techniques prior to a diagnostic scan (PET-CT. The aim of the study is twofold: firstly, it is sought to establish whether such techniques can minimize patient arousal before diagnostic screening begins, and secondly to measure which of them are most effective. The dependent variable is electrodermal activity, recording the attentional level and emotional response, and the independent variable comprises the relaxation techniques used, namely Jacobson, breathing and visualization. The 39 patients were split into experimental groups to whom the relaxation techniques (Jacobson, breathing exercises, and visualization were applied before they went for the PET-CT. An activity-module procedure was applied to track electrodermal activity during the relaxation sessions, consisting of instructions, timeout; wait, task; relaxation and end of the recording session. The control group received no relaxation techniques before the PET-CT. Session-end results show that patients who perform relaxation techniques achieve greater attentional focus using Jacobson's technique (M = .212 and enhanced emotional containment using visualization (M = .206. It is concluded that relaxation techniques minimize the state of activation during the waiting period before a diagnostic scan.

  8. Dual structures for the sole-proprietorship firm

    OpenAIRE

    Chambers, Robert G.; Quiggin, John

    2003-01-01

    This paper presents a dual representation of firm-level and market-level equilibrium behavior for a sole proprietorship economy with competitive and frictionless financial markets and stochastic production opportunities in a two-period setting. The dual equilibrium model is used to state conditions for the firms' production choices to be independent of their risk preferences in equilibrium. These conditions entail Pareto optimality, but do not require either that the firm's consumption choice...

  9. A Mole in the Sole: Case Report on Eccrine Poroma

    Directory of Open Access Journals (Sweden)

    Dr. Arnab Ghosh

    2007-01-01

    Full Text Available Eccrine poroma is a benign tumor which arises from the intraepidermal portion of the eccrine sweat glands. 81 year old diabetic grandma worried about her persistently uncontrolled blood sugar owing to a painless mole in the sole of right foot for 2 years. Excisional biopsy revealed a sweat duct benign eccrine poroma. A relationship with diabetes mellitus could not be clearly established in this case.

  10. On the Volterra integral equation relating creep and relaxation

    International Nuclear Information System (INIS)

    Anderssen, R S; De Hoog, F R; Davies, A R

    2008-01-01

    The evolving stress–strain response of a material to an applied deformation is causal. If the current response depends on the earlier history of the stress–strain dynamics of the material (i.e. the material has memory), then Volterra integral equations become the natural framework within which to model the response. For viscoelastic materials, when the response is linear, the dual linear Boltzmann causal integral equations are the appropriate model. The choice of one rather than the other depends on whether the applied deformation is a stress or a strain, and the associated response is, respectively, a creep or a relaxation. The duality between creep and relaxation is known explicitly and is referred to as the 'interconversion equation'. Rheologically, its importance relates to the fact that it allows the creep to be determined from knowledge of the relaxation and vice versa. Computationally, it has been known for some time that the recovery of the relaxation from the creep is more problematic than the creep from the relaxation. Recent research, using discrete models for the creep and relaxation, has confirmed that this is an essential feature of interconversion. In this paper, the corresponding result is generalized for continuous models of the creep and relaxation

  11. Effect of ski mountaineering track on foot sole loading pattern.

    Science.gov (United States)

    Haselbacher, Matthias; Mader, Katharina; Werner, Maximiliane; Nogler, Michael

    2014-09-01

    Ski mountaineering is becoming a popular sport. The ascending techniques (tracks) can be divided into 3 different groups: flat field, direct ascent, and traversing. This study examines the relationship between different mechanical loads on the foot and the 4 different mountaineering ascending techniques. All subjects used the same pair of ski boots and the same skis while performing the 4 different ascending techniques. An in-shoe dynamic pressure measuring system was used to measure the mechanical load on the foot soles of each ski mountaineer. The foot sole was divided into 6 anatomic sections to measure the different loads in each section. Thirteen men with an average age of 29 years were enrolled in the study. The results showed small, not significant differences in the mechanical foot load in the flat field or in the direct ascent. The average mechanical foot load was highest on the valley side foot while traversing (179 kPa to 117 kPa). The higher load forces were in the medial ball of the foot and the longitudinal aspect of the foot side closer to the hill. The higher impact placed on the valley side foot and the concentration of force placed on the medial ball of the valley side foot suggested the influence of the track on the load pattern of the foot sole. This higher impact may result in upward forces that affect the force distribution in the ankle and knee joints. Copyright © 2014. Published by Elsevier Inc.

  12. Improving Quality of Shoe Soles Product using Six Sigma

    Science.gov (United States)

    Jesslyn Wijaya, Athalia; Trusaji, Wildan; Akbar, Muhammad; Ma’ruf, Anas; Irianto, Dradjad

    2018-03-01

    A manufacture in Bandung produce kind of rubber-based product i.e. trim, rice rollers, shoe soles, etc. After penetrating the shoe soles market, the manufacture has met customer with tight quality control. Based on the past data, defect level of this product was 18.08% that caused the manufacture’s loss of time and money. Quality improvement effort was done using six sigma method that included phases of define, measure, analyse, improve, and control (DMAIC). In the design phase, the object’s problem and definition were defined. Delphi method was also used in this phase to identify critical factors. In the measure phase, the existing process stability and sigma quality level were measured. Fishbone diagram and failure mode and effect analysis (FMEA) were used in the next phase to analyse the root cause and determine the priority issues. Improve phase was done by designing alternative improvement strategy using 5W1H method. Some improvement efforts were identified, i.e. (i) modifying design of the hanging rack, (ii) create pantone colour book and check sheet, (iii) provide pedestrian line at compound department, (iv) buying stop watch, and (v) modifying shoe soles dies. Some control strategies for continuous improvement were proposed such as SOP or reward and punishment system.

  13. Relaxation towards phase-locked dynamics in long Josephson junctions

    DEFF Research Database (Denmark)

    Salerno, M.; Grønbech-Jensen, Niels; Samuelsen, Mogens Rugholm

    1995-01-01

    We study the relaxation phenomenon towards phase-locked dynamics in long Josephson junctions. In particular the dependence of the relaxation frequency for the equal time of flight solution on the junction parameters is derived. The analysis is based on a phase-locked map and is compared with direct...... numerical experiments performed both on the map and on the perturbed sine-Gordon equation. As an interesting result we find that very close to a bifurcation the relaxation frequency is exactly equal to the half of the step frequency, i.e., the frequency characterizing the period-one solution....

  14. A moving mesh method with variable relaxation time

    OpenAIRE

    Soheili, Ali Reza; Stockie, John M.

    2006-01-01

    We propose a moving mesh adaptive approach for solving time-dependent partial differential equations. The motion of spatial grid points is governed by a moving mesh PDE (MMPDE) in which a mesh relaxation time \\tau is employed as a regularization parameter. Previously reported results on MMPDEs have invariably employed a constant value of the parameter \\tau. We extend this standard approach by incorporating a variable relaxation time that is calculated adaptively alongside the solution in orde...

  15. Nuclear relaxation in semiconductors doped with magnetic impurities

    International Nuclear Information System (INIS)

    Mel'nichuk, S.V.; Tovstyuk, N.K.

    1984-01-01

    The temperature and concentration dependences are investigated of the nuclear spin-lattice relaxation time with account of spin diffusion for degenerated and non-degenerated semicon- ductors doped with magnetic impurities. In case of the non-degenerated semiconductor the time is shown to grow with temperature, while in case of degenerated semiconductor it is practically independent of temperature. The impurity concentration growth results in decreasing the spin-lattice relaxation time

  16. Milrinone relaxes pulmonary veins in guinea pigs and humans.

    Directory of Open Access Journals (Sweden)

    Annette D Rieg

    Full Text Available INTRODUCTION: The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH. However, its action on pulmonary veins (PVs is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs and humans. MATERIAL AND METHODS: Precision-cut lung slices (PCLS were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL. RESULTS: In the IPL (GP, milrinone (10 µM lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP, milrinone relaxed naïve and pre-constricted PVs (120% and this relaxation was attenuated by inhibition of protein kinase G (KT 5823, adenyl cyclase (SQ 22536 and protein kinase A (KT 5720, but not by inhibition of NO-synthesis (L-NAME. In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+- and Kv-channels. Human PVs also relaxed to milrinone (121%, however only if pre-constricted. DISCUSSION: Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

  17. Milrinone relaxes pulmonary veins in guinea pigs and humans.

    Science.gov (United States)

    Rieg, Annette D; Suleiman, Said; Perez-Bouza, Alberto; Braunschweig, Till; Spillner, Jan W; Schröder, Thomas; Verjans, Eva; Schälte, Gereon; Rossaint, Rolf; Uhlig, Stefan; Martin, Christian

    2014-01-01

    The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans. Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL). In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+)- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted. Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+)- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

  18. Stress relaxation of thermally bowed fuel pins

    International Nuclear Information System (INIS)

    Crossland, I.G.; Speight, M.V.

    1983-01-01

    The presence of cross-pin temperature gradients in nuclear reactor fuel pins produces differential thermal expansion which, in turn, causes the fuel pin to bow elastically. If the pin is restrained in any way, such thermal bowing causes the pin to be stressed. At high temperatures these stresses can relax by creep and it is shown here that this causes the pin to suffer an additional permanent deflection, so that when the cross-pin temperature difference is removed the pin remains bowed. By representing the cylindrical pin by an equivalent I-beam, the present work examines this effect when it takes place by secondary creep. Two restraint systems are considered, and it is demonstrated that the rate of relaxation depends mainly upon the creep equation, and hence the temperature, and also the magnitude of the initial stresses. (author)

  19. Creep and relaxation behavior of Inconel-617

    International Nuclear Information System (INIS)

    Osthoff, W.; Ennis, P.J.; Nickel, H.; Schuster, H.

    1984-01-01

    The static and dynamic creep behavior of Inconel alloy 617 has been determined in constant load creep tests, relaxation tests, and stress reduction tests in the temperature range 1023 to 1273 K. The results have been interpreted using the internal stress concept: The dependence of the internal stress on the applied stress and test temperature was determined. In a few experiments, the influence of cold deformation prior to the creep test on the magnitude of the internal stress was also investigated. It was found that the experimentally observed relaxation behavior could be more satisfactorily described using the Norton creep equation modified by incorporation of the internal stress than by the conventional Norton creep equation

  20. Biexciton relaxation associated with dissociation into a surface polariton pair in semiconductor films

    Science.gov (United States)

    Mitsumori, Yasuyoshi; Matsuura, Shimpei; Uchiyama, Shoichi; Saito, Kentarao; Edamatsu, Keiichi; Nakayama, Masaaki; Ajiki, Hiroshi

    2018-04-01

    We study the biexciton relaxation process in CuCl films ranging from 6 to 200 nm. The relaxation time is measured as the dephasing time and the lifetime. We observe a unique thickness dependence of the biexciton relaxation time and also obtain an ultrafast relaxation time with a timescale as short as 100 fs, while the exciton lifetime monotonically decreases with increasing thickness. By analyzing the exciton-photon coupling energy for a surface polariton, we theoretically calculate the biexciton relaxation time as a function of the thickness. The calculated dependence qualitatively reproduces the observed relaxation time, indicating that the biexciton dissociation into a surface polariton pair is one of the major biexciton relaxation processes.

  1. Dynamics of the α-relaxation in glass-forming polymers. Study by neutron scattering and relaxation techniques

    Science.gov (United States)

    Colmenero, J.

    1993-12-01

    The dynamics of the α-relaxation in three different polymeric systems, poly(vinyl methyl ether) (PVME), poly(vinyl chloride) (PVC) and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of relaxation techniques and quasielastic neutron scattering (backscattering spectrometers IN10 and IN13 at the ILL-Grenoble). By using these techniques we have covered a wide time scale ranging from mesoscopic to macroscopic times (10 -10 -10 1 s). For analyzing the experimental data we have developed a phenomenological procedure in the frequency domain based on the Havriliak-Negami relaxation function, which in fact implies a Kohlrausch-Williams-Watts relaxation function in the time domain. The results obtained indicate that the dynamics of the α-relaxation in a wide time scale shows a clear non-Debye behaviour. The shape of the relaxation functions is found to be similar for the different techniques used and independent of temperature and momentum transfer ( Q). Moreover, the characteristic relaxation times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. Besides we found that the Q-dependence of the relaxation times obtained by QENS is given by a power law, τ( Q) ∞ Q- n ( n>2), n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. In the case of PVC, time of flight (TOF) neutron scattering experiments confirm these results in a shorter time scale (2×10 -11 -2× 10 -12 s). Moreover, TOF results also suggest the possibility of interpreting the “fast process” usually detected in glass-forming systems as a Debye-like short regime of the α-relaxation.

  2. Relaxation effect of abacavir on rat basilar arteries.

    Directory of Open Access Journals (Sweden)

    Rachel Wai Sum Li

    Full Text Available The use of abacavir has been linked with increased cardiovascular risk in patients with human immunodeficiency virus infection; however, the mechanism involved remains unclear. We hypothesize that abacavir may impair endothelial function. In addition, based on the structural similarity between abacavir and adenosine, we propose that abacavir may affect vascular contractility through endogenous adenosine release or adenosine receptors in blood vessels.The relaxation effect of abacavir on rat basilar arteries was studied using the myograph technique. Cyclic GMP and AMP levels were measured by immunoassay. The effects of abacavir on nucleoside transporters were studied using radiolabeled nucleoside uptake experiments. Ecto-5' nucleotidase activity was determined by measuring the generation of inorganic phosphate using adenosine monophosphate as the substrate.Abacavir induced the relaxation of rat basilar arteries in a concentration-dependent manner. This relaxation was abolished when endothelium was removed. In addition, the relaxation was diminished by the nitric oxide synthase inhibitor, L-NAME, the guanylyl cyclase inhibitor, ODQ, and the protein kinase G inhibitor, KT5820. Abacavir also increased the cGMP level in rat basilar arteries. Abacavir-induced relaxation was also abolished by adenosine A2 receptor blockers. However, abacavir had no effect on ecto-5' nucleotidase and nucleoside transporters. Short-term and long-term treatment of abacavir did not affect acetylcholine-induced relaxation in rat basilar arteries.Abacavir induces acute endothelium-dependent relaxation of rat basilar arteries, probably through the activation of adenosine A2 receptors in endothelial cells, which subsequently leads to the release of nitric oxide, resulting in activation of the cyclic guanosine monophosphate/protein kinase G-dependent pathway in vascular smooth muscle cells. It is speculated that abacavir-induced cardiovascular risk may not be related to

  3. Relaxed Bell inequalities and Kochen-Specker theorems

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Michael J. W. [Theoretical Physics, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2011-08-15

    The combination of various physically plausible properties, such as no signaling, determinism, and experimental free will, is known to be incompatible with quantum correlations. Hence, these properties must be individually or jointly relaxed in any model of such correlations. The necessary degrees of relaxation are quantified here via natural distance and information-theoretic measures. This allows quantitative comparisons between different models in terms of the resources, such as the number of bits of randomness, communication, and/or correlation, that they require. For example, measurement dependence is a relatively strong resource for modeling singlet-state correlations, with only 1/15 of one bit of correlation required between measurement settings and the underlying variable. It is shown how various ''relaxed'' Bell inequalities may be obtained, which precisely specify the complementary degrees of relaxation required to model any given violation of a standard Bell inequality. The robustness of a class of Kochen-Specker theorems, to relaxation of measurement independence, is also investigated. It is shown that a theorem of Mermin remains valid unless measurement independence is relaxed by 1/3. The Conway-Kochen ''free will'' theorem and a result of Hardy are less robust, failing if measurement independence is relaxed by only 6.5% and 4.5%, respectively. An appendix shows that existence of an outcome-independent model is equivalent to existence of a deterministic model.

  4. Nuclear spin-lattice relaxation in carbon nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Panich, A.M., E-mail: pan@bgu.ac.i [Department of Physics, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Sergeev, N.A. [Institute of Physics, University of Szczecin, 70-451 Szczecin (Poland)

    2010-04-15

    Interpretation of nuclear spin-lattice relaxation data in the carbon nanostructures is usually based on the analysis of fluctuations of dipole-dipole interactions of nuclear spins and anisotropic electron-nuclear interactions responsible for chemical shielding, which are caused by molecular dynamics. However, many nanocarbon systems such as fullerene and nanotube derivatives, nanodiamonds and carbon onions reveal noticeable amount of paramagnetic defects with unpaired electrons originating from dangling bonds. The interaction between nuclear and electron spins strongly influences the nuclear spin-lattice relaxation, but usually is not taken into account, thus the relaxation data are not correctly interpreted. Here we report on the temperature dependent NMR spectra and spin-lattice relaxation measurements of intercalated fullerenes C{sub 60}(MF{sub 6}){sub 2} (M=As and Sb), where nuclear relaxation is caused by both molecular rotation and interaction between nuclei and unpaired electron spins. We present a detailed theoretical analysis of the spin-lattice relaxation data taking into account both these contributions. Good agreement between the experimental data and calculations is obtained. The developed approach would be useful in interpreting the NMR relaxation data in different nanostructures and their intercalation compounds.

  5. Calorimetric and relaxation properties of xylitol-water mixtures

    Science.gov (United States)

    Elamin, Khalid; Sjöström, Johan; Jansson, Helén; Swenson, Jan

    2012-03-01

    We present the first broadband dielectric spectroscopy (BDS) and differential scanning calorimetry study of supercooled xylitol-water mixtures in the whole concentration range and in wide frequency (10-2-106 Hz) and temperature (120-365 K) ranges. The calorimetric glass transition, Tg, decreases from 247 K for pure xylitol to about 181 K at a water concentration of approximately 37 wt. %. At water concentrations in the range 29-35 wt. % a plentiful calorimetric behaviour is observed. In addition to the glass transition, almost simultaneous crystallization and melting events occurring around 230-240 K. At higher water concentrations ice is formed during cooling and the glass transition temperature increases to a steady value of about 200 K for all higher water concentrations. This Tg corresponds to an unfrozen xylitol-water solution containing 20 wt. % water. In addition to the true glass transition we also observed a glass transition-like feature at 220 K for all the ice containing samples. However, this feature is more likely due to ice dissolution [A. Inaba and O. Andersson, Thermochim. Acta, 461, 44 (2007)]. In the case of the BDS measurements the presence of water clearly has an effect on both the cooperative α-relaxation and the secondary β-relaxation. The α-relaxation shows a non-Arrhenius temperature dependence and becomes faster with increasing concentration of water. The fragility of the solutions, determined by the temperature dependence of the α-relaxation close to the dynamic glass transition, decreases with increasing water content up to about 26 wt. % water, where ice starts to form. This decrease in fragility with increasing water content is most likely caused by the increasing density of hydrogen bonds, forming a network-like structure in the deeply supercooled regime. The intensity of the secondary β-relaxation of xylitol decreases noticeably already at a water content of 2 wt. %, and at a water content above 5 wt. % it has been replaced by a

  6. Relaxed states of tokamak plasmas

    International Nuclear Information System (INIS)

    Kucinski, M.Y.; Okano, V.

    1993-01-01

    The relaxed states of tokamak plasmas are studied. It is assumed that the plasma relaxes to a quasi-steady state which is characterized by a minimum entropy production rate, compatible with a number of prescribed conditions and pressure balance. A poloidal current arises naturally due to the anisotropic resistivity. The minimum entropy production theory is applied, assuming the pressure equilibrium as fundamental constraint on the final state. (L.C.J.A.)

  7. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  8. Relaxation effects in ferrous complexes

    International Nuclear Information System (INIS)

    Nicolini, C.; Mathieu, J.P.; Chappert, J.

    1976-01-01

    The slow relaxation mechanism of the Fe 2+ ion in the tri-fluorinated TF(acac) and hexafluorinated HF(acac) complexes of Fe(II) acetylacetonate was investigated. The 300K and 77K Moessbauer spectra for TF(acac) consist in a slightly asymmetric quadrupole doublet. On the contrary, at 4.2K the higher energy line is strongly widened; that is typical of a slowing down in the electron relaxation frequency [fr

  9. Use of Powder PEG-3350 as a Sole Bowel Preparation

    Science.gov (United States)

    Arora, Manish

    2008-01-01

    Objective: To assess the efficacy of low-volume powder polyethylene glycol (PEG)-3350 as a sole bowel preparation for colonoscopy. Methods: This case series examined 245 consecutive patients (a mixture of inpatients and outpatients undergoing screening colonoscopy) at a hospital endoscopy center over a 2-year period. The patients received powder PEG-3350 in the amount of 204 g dissolved in 32 oz of water and taken in 3 divided doses 1 hour apart with 8 oz of water in between each dose. Colon preparation scores (CPS) were used to assess the quality of colon cleansing. The results obtained from the 245 patients were collated and compared to those of patients receiving sodium phosphate, the historical control. Results: The mean CPS was calculated to be 3.43, with a standard deviation of 1.12. Of the 245 patients, 92 were scored with a grade of 4, and 5 patients had incomplete colonoscopies secondary to failure of bowel preparation (CPS=0). Among the remaining patients, 22 and 26 were graded as poor (CPS=1) or fair (CPS=2) bowel preparations, respectively. Conclusion: The low-volume powder PEG-3350 formula used in our case series showed effective colon cleansing and may be considered for use as a sole bowel preparation. PMID:21960925

  10. Inherent variation in multiple shoe-sole test impressions.

    Science.gov (United States)

    Shor, Yaron; Wiesner, Sarena; Tsach, Tsadok; Gurel, Ron; Yekutieli, Yoram

    2018-04-01

    Shoeprints left at crime scenes are seldom perfect. Many prints are distorted or contaminated by various materials. Noisy background often contributes to vagueness on the shoeprints as well. Test impressions made from the suspect's shoes in the laboratory are considered a genuine replication of the shoe-sole. This naïve attitude is far from being correct. Consecutive test impressions made in the laboratory under strict similar conditions revealed differences among the exemplars of the same sole. Some of them are minor, but some are major, and can mislead the less experienced practitioners during the comparison process. This article focuses on the inherent within source variability between controlled shoeprints made from the same shoe, as it appears on the RACs. To describe and analyze this variability, repeated test impressions were prepared, and datasets were created. Several RACs were marked on each test impression, using an expert assisting software tool (developed in the authors' lab). The variance in repeated test impressions is demonstrated and possible sources are discussed. This variance should be considered when trying to establish the degree of matching between individual characteristics. Copyright © 2017. Published by Elsevier B.V.

  11. Trisomy 19 as the sole chromosomal anomaly in hematologic neoplasms.

    Science.gov (United States)

    Johansson, B; Billström, R; Mauritzson, N; Mitelman, F

    1994-05-01

    Trisomy 19 was found as the sole chromosomal aberration in three hematologic malignancies: one chronic myelomonocytic leukemia and two cases of of immunophenotypically immature acute myeloid leukemia (AML). A compilation of previously published hematologic neoplasms with +19 as the only change reveals that this anomaly is strongly associated with myeloid malignancies; 25 of 31 cases have been myelodysplastic syndromes (MDS) or AML. Eight of the 11 MDS cases have been either refractory anemia (RA) or RA with excess of blasts, and four of the 14 AML cases have had preleukemic myelodysplastic cases phase, with the +19 accruing during the time of leukemic transformation. The AML cases have, in general, been either or early maturation arrest, i.e. undifferentiated or AML-M1/M2, or of myelomonocytic-monoblastic origin, i.e., AML-M4/M5. None of the MDS or AML cases with +19 had had a previous history of radio- or chemotherapy. We conclude that trisomy 19, as the sole anomaly, is a characteristic abnormality in de novo myeloid malignancies. No clinical features seem to characterize patients with +19 AML and MDS and the prognostic impact of the aberration remains to be elucidated.

  12. Proton NMR relaxation in hydrous melts

    International Nuclear Information System (INIS)

    Braunstein, J.; Bacarella, A.L.; Benjamin, B.M.; Brown, L.L.; Girard, C.

    1976-01-01

    Pulse and continuous wave NMR measurements are reported for protons in hydrous melts of calcium nitrate at temperatures between -4 and 120 0 C. Although measured in different temperature ranges, spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation times appear to be nearly equal to each other and proportional to the self-diffusion coefficients of solute metal cations such as Cd 2+ . At temperatures near 50 0 C, mean Arrhenius coefficients Δ H/sub T 1 / (kcal/mol) are 7.9, 7.3, and 4.8, respectively, for melts containing 2.8, 4.0, and 8.0 moles of water per mole of calcium nitrate, compared to 4.6 kcal/mol for pure water. Temperature dependence of T 1 and T 2 in Ca(NO 3 ) 2 -2.8 H 2 O between -4 and 120 0 C are non-Arrhenius and can be represented by a Fulcher-type equation with a ''zero mobility temperature'' (T 0 ) of 225 0 K, close to the value of T 0 for solute diffusion, electrical conductance and viscosity. Resolution of the relaxation rates into correlation times for intramolecular (rotational) and intermolecular (translational) diffusional motion is discussed in terms of the Bloembergen-Purcell-Pound and more recent models for dipolar relaxation

  13. Improved labeling strategy for 13C relaxation measurements of methyl groups in proteins

    International Nuclear Information System (INIS)

    Lee, Andrew L.; Urbauer, Jeffrey L.; Wand, A. Joshua

    1997-01-01

    Selective incorporation of 13 C into the methyl groups of protein side chains is described as a means for simplifying the measurement and interpretation of 13 C relaxation parameters.High incorporation (>90%) is accomplished by using pyruvate(3- 13 C, 99%) as the sole carbon source in the growth media for protein overexpression in E. coli. This improved labeling scheme increases the sensitivity of the relaxation experiments by approximately fivefold when compared to randomly fractionally 13 C-labeled protein, allowing high-quality measurements on relatively dilute (<1 mM)protein samples at a relatively low cost

  14. Modelling Creep (Relaxation of the Urinary Bladder

    Directory of Open Access Journals (Sweden)

    Zdravkovic Nebojsa

    2017-12-01

    Full Text Available We first present the results of an experiment in which the passive properties of the urinary bladder were investigated using strips of rabbit bladder. Under the assumption that the urinary bladder had orthopaedic characteristics, the strips were taken in the longitudinal and in the circumferential directions. The material was subjected to uniaxial tension, and stress-stretch curves were generated for various rates of deformation. We found that the rates did not have a significantly effect on the passive response of the material. Additionally, the stress-stretch dependence during relaxation of the material when exposed to isometric conditions was determined experimentally.

  15. Relaxation oscillations in stimulated Raman scattering

    International Nuclear Information System (INIS)

    Kachen, G.I.; Lowdermilk, W.H.

    1977-01-01

    Light pulses created by stimulated Raman scattering having been found to exhibit a complex time dependence which resembles relaxation oscillations. A focused laser pulse generated both forward and backward Raman emissions which appeared as a series of pulses with durations much shorter than the incident laser pulse. Time dependence of the Raman emission was observed directly by use of a streak camera. The number of observed pulses increased with the intensity of the incident pulse, while separation of the pulses in time depended on the length of the focal region. Beam focusing was incorporated in the coupled wave equations for stimulated Raman scattering. These rate equations were then solved numerically, and the results are in good qualitative agreement with the experimental observations. The short Raman pulses are created by a process associated with depletion of the incident laser pulse. This process occurs under a broad range of conditions

  16. Depth and substrate as determinants of distribution of juvenile flathead sole (Hippoglossoides elassodon) and rock sole (Pleuronectes bilineatus), in Kachemak Bay, Alaska

    Science.gov (United States)

    Abookire, Alisa A.; Norcross, Brenda L.

    1998-01-01

    Three transects in Kachemak Bay, Alaska, were sampled in September 1994, May and August 1995, and February, May, and August 1996. Juvenile flathead sole, Hippoglossoides elassodon, and rock sole, Pleuronectes bilineatus, were the most abundant flatfishes, comprising 65-85% of all fiatfishes captured at any period. Collections of fish and sediments were made at regular depth contour intervals of l0 m. Habitat distribution was described by depth at 10 m increments and sediment percent weights of gravel, sand, and mud. Year-round habitat of flathead sole age-0 was primarily from 40 to 60 m, and age-1 habitat was primarily from 40 to 80 m. Summer habitat of rock sole age-0 and -1 was from 10 to 30 m, and in winter they moved offshore to depths of up to 150 m. Both age classes of flathead sole were most abundant on mixed mud sediments, while age-1 were also in high abundance on muddy sand sediments. Rock sole age-0 and -1 were most abundant on sand, though age-1 were also found on a variety of sediments both finer and coarser grained than sand. Flathead sole and rock sole had distinctive depth and sediment habitats. When habitat overlap occurred between the species, it was most often due to rock sole moving offshore in the winter. Abundances were not significantly different among seasons for age-1 flatfishes.

  17. Parameterization of NMR relaxation curves in terms of logarithmic moments of the relaxation time distribution.

    Science.gov (United States)

    Petrov, Oleg V; Stapf, Siegfried

    2017-06-01

    This work addresses the problem of a compact and easily comparable representation of multi-exponential relaxation data. It is often convenient to describe such data in a few parameters, all being of physical significance and easy to interpret, and in such a way that enables a model-free comparison between different groups of samples. Logarithmic moments (LMs) of the relaxation time constitute a set of parameters which are related to the characteristic relaxation time on the log-scale, the width and the asymmetry of an underlying distribution of exponentials. On the other hand, the calculation of LMs does not require knowing the actual distribution function and is reduced to a numerical integration of original data. The performance of this method has been tested on both synthetic and experimental NMR relaxation data which differ in a signal-to-noise ratio, the sampling range and the sampling rate. The calculation of two lower-order LMs, the log-mean time and the log-variance, has proved robust against deficiencies of the experiment such as scattered data point and incomplete sampling. One may consider using them as such to monitor formation of a heterogeneous structure, e.g., in phase separation, vitrification, polymerization, hydration, aging, contrast agent propagation processes. It may also assist in interpreting frequency and temperature dependences of relaxation, revealing a crossover from slow to fast exchange between populations. The third LM was found to be a less reliable quantity due to its susceptibility to the noise and must be used with caution. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Parameterization of NMR relaxation curves in terms of logarithmic moments of the relaxation time distribution

    Science.gov (United States)

    Petrov, Oleg V.; Stapf, Siegfried

    2017-06-01

    This work addresses the problem of a compact and easily comparable representation of multi-exponential relaxation data. It is often convenient to describe such data in a few parameters, all being of physical significance and easy to interpret, and in such a way that enables a model-free comparison between different groups of samples. Logarithmic moments (LMs) of the relaxation time constitute a set of parameters which are related to the characteristic relaxation time on the log-scale, the width and the asymmetry of an underlying distribution of exponentials. On the other hand, the calculation of LMs does not require knowing the actual distribution function and is reduced to a numerical integration of original data. The performance of this method has been tested on both synthetic and experimental NMR relaxation data which differ in a signal-to-noise ratio, the sampling range and the sampling rate. The calculation of two lower-order LMs, the log-mean time and the log-variance, has proved robust against deficiencies of the experiment such as scattered data point and incomplete sampling. One may consider using them as such to monitor formation of a heterogeneous structure, e.g., in phase separation, vitrification, polymerization, hydration, aging, contrast agent propagation processes. It may also assist in interpreting frequency and temperature dependences of relaxation, revealing a crossover from slow to fast exchange between populations. The third LM was found to be a less reliable quantity due to its susceptibility to the noise and must be used with caution.

  19. Peeling mode relaxation ELM model

    International Nuclear Information System (INIS)

    Gimblett, C. G.

    2006-01-01

    This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made

  20. Mechanisms of friction and assessment of slip resistance of new and used footwear soles on contaminated floors.

    Science.gov (United States)

    Grönqvist, Raoul

    1995-02-01

    The great number of slipping accidents indicates that footwear providing good slip resistance must be rare. Slip resistance seems to be a purely physical phenomenon, however, more knowledge of the mechanisms of friction is needed to develop slip-resistant footwear and to ensure safer walking in slippery conditions. In the present study the influence of the normal wear of shoe heels and soles on their frictional properties was clarified. The slip resistance of three types of new and used safety shoes on four relatively slippery floor-contaminant combinations, was assessed with a prototype apparatus, which simulates the movements of a human foot and the forces applied to the underfoot surface during an actual slip. The used shoes were collected from 27 workers in a shipbuilding company and classified by sight into four wear classes: Good, satisfactory, poor, and worn-out. The assessed shoe heels and soles were in general more slippery when new compared to used heels and soles. However, footwear must be discarded before the tread pattern is worn-out. Used microcellular polyurethane (PU) heels and soles gave a considerably higher coefficient of kinetic friction (μ k ) on contaminated floors than used heels and soles made of compact nitrile (NR) and compact styrene rubber (SR). The heel-slide coefficient of kinetic friction (μ kl ) for used versus new shoes was on average 66% higher for PU (0·216 versus 0·130), 27% higher for SR (0·143 versus 0·113), and 7% lower for NR (0·098 versus 0·105). The fundamental mechanisms of friction between shoe soles and contaminated floors were also discussed, and experiments with seven slabs of sole materials were carried out to assess contact pressure effects from the viewpoint of slipping. Slip resistance particularly seemed to depend on the squeeze film and the contact pressure effects between the soling materials and the floor. An increasing contact pressure dramatically reduced the μ k , thus indicating that the slip

  1. Topology Synthesis of Structures Using Parameter Relaxation and Geometric Refinement

    Science.gov (United States)

    Hull, P. V.; Tinker, M. L.

    2007-01-01

    Typically, structural topology optimization problems undergo relaxation of certain design parameters to allow the existence of intermediate variable optimum topologies. Relaxation permits the use of a variety of gradient-based search techniques and has been shown to guarantee the existence of optimal solutions and eliminate mesh dependencies. This Technical Publication (TP) will demonstrate the application of relaxation to a control point discretization of the design workspace for the structural topology optimization process. The control point parameterization with subdivision has been offered as an alternative to the traditional method of discretized finite element design domain. The principle of relaxation demonstrates the increased utility of the control point parameterization. One of the significant results of the relaxation process offered in this TP is that direct manufacturability of the optimized design will be maintained without the need for designer intervention or translation. In addition, it will be shown that relaxation of certain parameters may extend the range of problems that can be addressed; e.g., in permitting limited out-of-plane motion to be included in a path generation problem.

  2. Mechanical relaxation in chalcogenide glasses of the Ge-As-S system

    International Nuclear Information System (INIS)

    Bilanych, V.S.; Melnychenko, T.D.; Rizak, V.M.; Makauz, I.I.

    2006-01-01

    The temperature and frequency-related dependences of the internal friction and the shear modulus in Ge x As 40-x S 60 glasses have been studied. The maxima of internal friction of both the relaxation and non relaxation types have been found in the low-temperature range. A relaxation maximum has been revealed in the vitrification region, and its parameters have been determined. Possible mechanisms of these processes have been discussed

  3. Clinical assessment of dynamic coefficient of friction effects in shoe-sole trituration of patients with drop foot.

    Science.gov (United States)

    Nima, Jamshidi; Firooz, Salami

    2012-06-01

    The aim of this study was examining the effect of human factors such as plantar friction, contact period time, and impulse on shoe-sole trituration of drop foot patients. Twenty-five patients with drop foot and twenty normal subjects were recruited in the study. The force plate and its related software's recorded human factor (coefficient of friction, ground reaction force, time of stance phase) as time dependent parameters. Dynamic coefficient of friction patterns were categorized based on their magnitude versus time when the longitudinal axis of the sole was plotted as the Y-axis and the transverse axis of the sole as X-axis during stance phase. The result of this research indicated that the average coefficient of friction among drop foot patients is 77.53 % (p value <0.05) lower than the normal subjects. Also the time of stance phase among drop foot patients is 7.56 % (p value <0.05) greater than normal subjects. There is no difference in the peaks, of vertical ground reaction force between normal and control group. The findings of this research revealed that the time of stance phase has a key role in shoe-sole trituration of patients with drop foot.

  4. Sole-Source Lighting for Controlled-Environment Agriculture

    Science.gov (United States)

    Mitchell.Cary; Stutte, Gary W.

    2015-01-01

    Since plants on Earth evolved under broad-spectrum solar radiation, anytime they are grown exclusively under electric lighting that does not contain all wavelengths in similar proportion to those in sunlight, plant appearance and size could be uniquely different. Nevertheless, plants have been grown for decades under fluorescent (FL) (1) + incandescent (IN) (2) lamps as a sole source of lighting (SSL), and researchers have become comfortable that, in certain proportions of FL + IN for a given species, plants can appear "normal" relative to their growth outdoors. The problem with using such traditional SSLs for commercial production typically is short lamp lifespans and not obtaining enough photosynthetically active radiation (PAR, 400-700 nm) when desired. These limitations led to supplementation of FL + IN lamp outputs with longer-lived, high-intensity discharge (HID) lamps in growth chambers (3). As researchers became comfortable that mixes of orange-biased high-pressure sodium (HPS) and blue-biased metal halide (MH) HIDs together also could give normal plant growth at higher intensities, growth chambers and phytotrons subsequently were equipped mainly with HID lamps, with their intense thermal output filtered out by ventilated light caps or thermal-controlled water barriers. For the most part, IN and HID lamps have found a home in commercial protected horticulture, usually for night-break photoperiod lighting (IN) or for seasonal supplemental lighting (mostly HPS) in greenhouses. However, lack of economically viable options for SSL have held back aspects of year-round indoor agriculture from taking off commercially.

  5. Ammonium as sole N source improves grain quality in wheat.

    Science.gov (United States)

    Fuertes-Mendizábal, Teresa; González-Torralba, Jon; Arregui, Luis M; González-Murua, Carmen; González-Moro, M Begoña; Estavillo, José M

    2013-07-01

    The skilful handling of N fertilizer, including N source type and its timing, is necessary to obtain maximum profitability in wheat crops in terms of production and quality. Studies on grain yield and quality with ammonium as sole N source have not yet been conducted. The aim of this study was to evaluate the effect of N source management (nitrate vs. ammonium), and splitting it into two or three amendments during the wheat life cycle, on grain yield and quality under irrigated conditions. This experiment demonstrates that Cezanne wheat plants growing with ammonium as exclusive N source are able to achieve the same yield as plants growing with nitrate and that individual wheat plants grown in irrigated pots can efficiently use late N applied in GS37. Ammonium nutrition increased both types of grain reserve proteins (gliadins and glutenins) and also increased the ratio gli/glu with respect to nitrate nutrition. The splitting of the N rate enhanced the ammonium effect on grain protein composition. The application of ammonium N source, especially when split into three amendments, has an analogous effect on grain protein content and composition to applications at a higher N rate, leading to higher N use efficiency. © 2012 Society of Chemical Industry.

  6. Holographic grating relaxation technique for soft matter science

    Energy Technology Data Exchange (ETDEWEB)

    Lesnichii, Vasilii, E-mail: vasilii.lesnichii@physchem.uni-freiburg.de [Institute of Physical Chemistry, Albertstraße 21, Institute of Macromolecular Chemistry, Stefan-Meier-Str. 31, Albert-Ludwigs Universität, Freiburg im Breisgau 79104 (Germany); ITMO University, Kronverksky prospekt 49, Saint-Petersburg 197101 (Russian Federation); Kiessling, Andy [Institute of Physical Chemistry, Albertstraße 21, Institute of Macromolecular Chemistry, Stefan-Meier-Str. 31, Albert-Ludwigs Universität, Freiburg im Breisgau 79104 (Germany); Current address: Illinois Institute of Technology, 10 West 33rd Street, Chicago,IL60616 (United States); Bartsch, Eckhard [Institute of Physical Chemistry, Albertstraße 21, Institute of Macromolecular Chemistry, Stefan-Meier-Str. 31, Albert-Ludwigs Universität, Freiburg im Breisgau 79104 (Germany); Veniaminov, Andrey, E-mail: veniaminov@phoi.ifmo.ru [ITMO University, Kronverksky prospekt 49, Saint-Petersburg 197101 (Russian Federation)

    2016-06-17

    The holographic grating relaxation technique also known as forced Rayleigh scattering consists basically in writing a holographic grating in the specimen of interest and monitoring its diffraction efficiency as a function of time, from which valuable information on mass or heat transfer and photoinduced transformations can be extracted. In a more detailed view, the shape of the relaxation curve and the relaxation rate as a function of the grating period were found to be affected by the architecture of diffusing species (molecular probes) that constitute the grating, as well as that of the environment they diffuse in, thus making it possible to access and study spatial heterogeneity of materials and different modes of e.g., polymer motion. Minimum displacements and spatial domains approachable by the technique are in nanometer range, well below spatial periods of holographic gratings. In the present paper, several cases of holographic relaxation in heterogeneous media and complex motions are exemplified. Nano- to micro-structures or inhomogeneities comparable in spatial scale with holographic gratings manifest themselves in relaxation experiments via non-exponential decay (stepwise or stretched), spatial-period-dependent apparent diffusion coefficient, or unusual dependence of diffusion coefficient on molecular volume of diffusing probes.

  7. F19 relaxation in non-magnetic hexafluorides

    International Nuclear Information System (INIS)

    Rigny, P.

    1969-01-01

    The interesting properties of the fluorine magnetic resonance in the hexafluorides of molybdenum, tungsten and uranium, are very much due to large anisotropies of the chemical shift tensors. In the solid phases these anisotropies, the values of which are deduced from line shape studies, allow one to show that the molecules undergo hindered rotations about the metal atom. The temperature and frequency dependence of the fluorine longitudinal relaxation times shows that the relaxation is due to the molecular motion. The dynamical parameters of this motion are then deduced from the complete study of the fluorine relaxation in the rotating frame. In the liquid phases, the existence of anisotropies allows an estimation of the different contributions to the relaxation. In particular, the frequency and temperature dependence of the relaxation shows it to be dominated by the spin-rotation interaction. We have shown that the strength of this interaction can be deduced from the chemical shifts, and the angle through which the molecule rotates quasi-freely can be determined. In the hexafluorides, this angle is roughly one radian at 70 C, and with the help of this value, the friction coefficients which describe the intermolecular interactions are discussed. (author) [fr

  8. Evolutionary Pseudo-Relaxation Learning Algorithm for Bidirectional Associative Memory

    Institute of Scientific and Technical Information of China (English)

    Sheng-Zhi Du; Zeng-Qiang Chen; Zhu-Zhi Yuan

    2005-01-01

    This paper analyzes the sensitivity to noise in BAM (Bidirectional Associative Memory), and then proves the noise immunity of BAM relates not only to the minimum absolute value of net inputs (MAV) but also to the variance of weights associated with synapse connections. In fact, it is a positive monotonically increasing function of the quotient of MAV divided by the variance of weights. Besides, the performance of pseudo-relaxation method depends on learning parameters (λ and ζ), but the relation of them is not linear. So it is hard to find a best combination of λ and ζ which leads to the best BAM performance. And it is obvious that pseudo-relaxation is a kind of local optimization method, so it cannot guarantee to get the global optimal solution. In this paper, a novel learning algorithm EPRBAM (evolutionary psendo-relaxation learning algorithm for bidirectional association memory) employing genetic algorithm and pseudo-relaxation method is proposed to get feasible solution of BAM weight matrix. This algorithm uses the quotient as the fitness of each individual and employs pseudo-relaxation method to adjust individual solution when it does not satisfy constraining condition any more after genetic operation. Experimental results show this algorithm improves noise immunity of BAM greatly. At the same time, EPRBAM does not depend on learning parameters and can get global optimal solution.

  9. Onsager relaxation of toroidal plasmas

    International Nuclear Information System (INIS)

    Samain, A.; Nguyen, F.

    1997-01-01

    The slow relaxation of isolated toroidal plasmas towards their thermodynamical equilibrium is studied in an Onsager framework based on the entropy metric. The basic tool is a variational principle, equivalent to the kinetic equation, involving the profiles of density, temperature, electric potential, electric current. New minimization procedures are proposed to obtain entropy and entropy production rate functionals. (author)

  10. Anisotropic spin relaxation in graphene

    NARCIS (Netherlands)

    Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.

    2008-01-01

    Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular

  11. Stochastic and Chaotic Relaxation Oscillations

    NARCIS (Netherlands)

    Grasman, J.; Roerdink, J.B.T.M.

    1988-01-01

    For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

  12. Tensions relaxation in Zircaloy-4

    International Nuclear Information System (INIS)

    Cuniberti, A.M.; Picasso, A.C.

    1990-01-01

    Traction and stress relaxation studies were performed on polycrystalline Zry-4 at room temperature. The effect of loading velocity on the plastic behaviour of the material is discussed, analysing log σ vs. log dε/dt at different deformation levels. The contribution introduced by the testing machine was taken into account in data evaluation. (Author). 7 refs., 3 figs., 3 tabs

  13. gamma. -relaxation process in crystallizable polymers

    Energy Technology Data Exchange (ETDEWEB)

    Mindiyarov, Kh G; Zelenev, Yu V; Bartenev, G M [Birskij Gosudarstvennyj Pedagogicheskij Inst. (USSR)

    1975-07-01

    In the present paper, with the aid of radiothermoluminescence technique ..gamma..-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to ..gamma..-rays of Co/sup 60/ at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the ..cap alpha.. - ..gamma..-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP ..cap alpha..-maximum may be absent. Dependence has been studied of the luminescence intensity in the ..cap alpha..- and ..gamma..-maxima (Isub(..cap alpha..)/Isub(..gamma..)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(..gamma..)re of crystallinity degree.

  14. Sleep, Stress & Relaxation: Rejuvenate Body & Mind

    Science.gov (United States)

    Sleep, Stress & Relaxation: Rejuvenate Body & Mind; Relieve Stress; best ways to relieve stress; best way to relieve stress; different ways to relieve stress; does smoking relieve stress; does tobacco relieve stress; how can I relieve stress; how can you relieve stress; how do I relieve stress; reduce stress; does smoking reduce stress; how can I reduce stress; how to reduce stress; reduce stress; reduce stress levels; reducing stress; smoking reduce stress; smoking reduces stress; stress reducing techniques; techniques to reduce stress; stress relief; best stress relief; natural stress relief; need stress relief; relief for stress; relief from stress; relief of stress; smoking and stress relief; smoking for stress relief; smoking stress relief; deal with stress; dealing with stress; dealing with anger; dealing with stress; different ways of dealing with stress; help dealing with stress; how to deal with anger; how to deal with stress; how to deal with stress when quitting smoking; stress management; free stress management; how can you manage stress; how do you manage stress; how to manage stress; manage stress; management of stress; management stress; managing stress; strategies for managing stress; coping with stress; cope with stress; copeing with stress; coping and stress; coping skills for stress; coping strategies for stress; coping strategies with stress; coping strategy for stress; coping with stress; coping with stress and anxiety; emotional health; emotional health; emotional health article; emotional health articles; deep relaxation; deep breathing relaxation techniques; deep muscle relaxation; deep relaxation; deep relaxation meditation; deep relaxation technique; deep relaxation techniques; meditation exercises; mindful exercises; mindful meditation exercises; online relaxation exercises; relaxation breathing exercises; relaxation exercise; relaxation exercises; stress relaxation; methods of relaxation for stress; relax stress; relax techniques stress

  15. Magnetic relaxation behaviour in Pr_2NiSi_3

    International Nuclear Information System (INIS)

    Pakhira, Santanu; Mazumdar, Chandan; Ranganathan, R.

    2016-01-01

    Time dependent isothemal remanent magnetizatin (IRM) behaviour for polycrystalline compound Pr_2NiSi_3 have been studied below its characteristic temperature. The compound undergoes slow magnetic relaxation with time. Along with competing interaction, non-magnetic atom disorder plays an important role in formation of non-equilibrium glassy like ground state for this compound.

  16. Energy equation for the analysis of magnetization relaxation to equilibrium

    Energy Technology Data Exchange (ETDEWEB)

    Bertotti, G. [IEN Galileo Ferraris, Materials Department, Strada delle Cacce, 91, I-10135 Torino (Italy)]. E-mail: bertotti@ien.it; Bonin, R. [Dipartimento di Fisica, Politecnico di Torino, I-10129 Torino (Italy); Magni, A. [IEN Galileo Ferraris, Materials Department, Strada delle Cacce, 91, I-10135 Torino (Italy); Mayergoyz, I.D. [Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland, 20742 (United States); Serpico, C. [Dipartimento di Ingegneria Elettrica, Universita di Napoli ' Federico II' , I-80125 Naples (Italy)

    2005-02-01

    Magnetization relaxation starting from a generic non-equilibrium state is analytically described. An equation for the energy decay is obtained. On this basis, an approximate expression for the magnetization motion during the ringing process is obtained in terms of Jacobi elliptic functions with time-dependent parameters.

  17. Energy equation for the analysis of magnetization relaxation to equilibrium

    International Nuclear Information System (INIS)

    Bertotti, G.; Bonin, R.; Magni, A.; Mayergoyz, I.D.; Serpico, C.

    2005-01-01

    Magnetization relaxation starting from a generic non-equilibrium state is analytically described. An equation for the energy decay is obtained. On this basis, an approximate expression for the magnetization motion during the ringing process is obtained in terms of Jacobi elliptic functions with time-dependent parameters

  18. Hotspot relaxation dynamics in a current-carrying superconductor

    Science.gov (United States)

    Marsili, F.; Stevens, M. J.; Kozorezov, A.; Verma, V. B.; Lambert, Colin; Stern, J. A.; Horansky, R. D.; Dyer, S.; Duff, S.; Pappas, D. P.; Lita, A. E.; Shaw, M. D.; Mirin, R. P.; Nam, S. W.

    2016-03-01

    We experimentally studied the dynamics of optically excited hotspots in current-carrying WSi superconducting nanowires as a function of bias current, bath temperature, and excitation wavelength. We observed that the hotspot relaxation time depends on bias current, temperature, and wavelength. We explained this effect with a model based on quasiparticle recombination, which provides insight into the quasiparticle dynamics of superconductors.

  19. Oil-in-oil emulsions stabilised solely by solid particles.

    Science.gov (United States)

    Binks, Bernard P; Tyowua, Andrew T

    2016-01-21

    A brief review of the stabilisation of emulsions of two immiscible oils is given. We then describe the use of fumed silica particles coated with either hydrocarbon or fluorocarbon groups in acting as sole stabilisers of emulsions of various vegetable oils with linear silicone oils (PDMS) of different viscosity. Transitional phase inversion of emulsions, containing equal volumes of the two oils, from silicone-in-vegetable (S/V) to vegetable-in-silicone (V/S) occurs upon increasing the hydrophobicity of the particles. Close to inversion, emulsions are stable to coalescence and gravity-induced separation for at least one year. Increasing the viscosity of the silicone oil enables stable S/V emulsions to be prepared even with relatively hydrophilic particles. Predictions of emulsion type from calculated contact angles of a silica particle at the oil-oil interface are in agreement with experiment provided a small polar contribution to the surface energy of the oils is included. We also show that stable multiple emulsions of V/S/V can be prepared in a two-step procedure using two particle types of different hydrophobicity. At fixed particle concentration, catastrophic phase inversion of emulsions from V/S to S/V can be effected by increasing the volume fraction of vegetable oil. Finally, in the case of sunflower oil + 20 cS PDMS, the study is extended to particles other than silica which differ in chemical type, particle size and particle shape. Consistent with the above findings, we find that only sufficiently hydrophobic particles (clay, zinc oxide, silicone, calcium carbonate) can act as efficient V/S emulsion stabilisers.

  20. Relaxation processes and structural transformations in amorphous Co-Fe-Si-B alloys

    International Nuclear Information System (INIS)

    Dus-Sitek, M.; Olszowski, Z.

    1994-01-01

    The thermostimulated electron emission (TSEE) method was applied for determination of relaxation and crystallization processes in amorphous alloys. By using the analogy of DTA-method, the activation energy of relaxation and crystallization processes has been determined from the measurements of changes of TSEE temperature maxima depending on the heating rate

  1. Effect of magnetic field on charge imbalance relaxation of non-equilibrium superconductivity

    International Nuclear Information System (INIS)

    Tsuboi, Kazuki; Yagi, Ryuta

    2010-01-01

    We have studied relaxation of charge imbalance of non-equilibrium superconductivity in magnetic field. We found that excess current due to charge imbalance showed striking dependence on magnitude of magnetic field and its orientation. We discussed origin of the relaxation.

  2. Investigation of the proteins relaxation time in human blood serum; Badania relaksacyjne bialek surowicy krwi II

    Energy Technology Data Exchange (ETDEWEB)

    Blicharska, B.; Klauza, M. [Inst. Fizyki, Uniwersytet Jagiellonski, Cracow (Poland); Kuliszkiewicz-Janus, M. [Akademia Medyczna, Wroclaw (Poland)

    1994-12-31

    In this paper the results of human blood serum proteins relaxation time measurements by means of NMR method are presented. The measurements have been done for three samples of human blood: i/laudably ii/leukemia iii/granulomas. The dependences of the relaxation time on the temperature are also presented. 3 refs, 4 figs.

  3. Picosecond buildup and relaxation of intense stimulated emission in GaAs

    International Nuclear Information System (INIS)

    Ageeva, N. N.; Bronevoi, I. L.; Zabegaev, D. N.; Krivonosov, A. N.

    2013-01-01

    In support of the idea developed previously based on circumstantial evidence, we have found that stimulated emission emerges in GaAs and its intensity increases with a picosecond delay relative to the front of powerful picosecond optical pumping that produced a dense electron-hole plasma. The emission intensity relaxes with decreasing pumping with a characteristic time of ∼10 ps. We have derived the dependences of the delay time, the relaxation time, and the duration of the picosecond emission pulse on its photon energy. The estimates based on the fact that the relaxation of emission is determined by electron-hole plasma cooling correspond to the measured relaxation time.

  4. Composition effect of potassium-borate glasses on their relaxation properties

    International Nuclear Information System (INIS)

    Lomovskoj, V.A.; Bartenev, G.M.

    1995-01-01

    Relaxation processes in potassium-borate glasses have been investigated in detail for the first time. It is shown that low-temperature β-process of relaxation relating to rotational mobility of the B-O bond is the same for all potassium-borate glasses and B 2 O 3 . The process of β k -relaxation related to diffusion mobility of potassium ions depends on the composition of the glasses in the same way as α-relaxation (glass formation).12 refs., 10 figs., 2 tabs

  5. Suppression of Dyakonov-Perel Spin Relaxation in High-Mobility n-GaAs

    Science.gov (United States)

    Dzhioev, R. I.; Kavokin, K. V.; Korenev, V. L.; Lazarev, M. V.; Poletaev, N. K.; Zakharchenya, B. P.; Stinaff, E. A.; Gammon, D.; Bracker, A. S.; Ware, M. E.

    2004-11-01

    We report a large and unexpected suppression of the free electron spin-relaxation in lightly doped n-GaAs bulk crystals. The spin-relaxation rate shows a weak mobility dependence and saturates at a level 30 times less than that predicted by the Dyakonov-Perel theory. The dynamics of the spin-orbit field differs substantially from the usual scheme: although all the experimental data can be self-consistently interpreted as a precessional spin-relaxation induced by a random spin-orbit field, the correlation time of this random field, surprisingly, is much shorter than, and is independent of, the momentum relaxation time determined from transport measurements.

  6. A simple measurement method of molecular relaxation in a gas by reconstructing acoustic velocity dispersion

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Zhang, Xiangqun; Li, Caiyun

    2018-01-01

    Recently, a decomposition method of acoustic relaxation absorption spectra was used to capture the entire molecular multimode relaxation process of gas. In this method, the acoustic attenuation and phase velocity were measured jointly based on the relaxation absorption spectra. However, fast and accurate measurements of the acoustic attenuation remain challenging. In this paper, we present a method of capturing the molecular relaxation process by only measuring acoustic velocity, without the necessity of obtaining acoustic absorption. The method is based on the fact that the frequency-dependent velocity dispersion of a multi-relaxation process in a gas is the serial connection of the dispersions of interior single-relaxation processes. Thus, one can capture the relaxation times and relaxation strengths of N decomposed single-relaxation dispersions to reconstruct the entire multi-relaxation dispersion using the measurements of acoustic velocity at 2N  +  1 frequencies. The reconstructed dispersion spectra are in good agreement with experimental data for various gases and mixtures. The simulations also demonstrate the robustness of our reconstructive method.

  7. Nuclear quadrupole relaxation and viscosity in liquid metals

    International Nuclear Information System (INIS)

    Schirmacher, W.

    1976-01-01

    It is shown that the nuclear quadrupole relaxation rate due to the molecular motions in liquid metals is related to the shear and bulk viscosity and hence to the absorption coefficient of ultrasound. Application of the 'extended liquid phonon' model of Ortoleva and Nelkin - which is the third of a series of continued-fraction-approximations for the van Hove neutron scattering function - gives a relation to the self diffusion constant. The predictions of the theory concerning the temperature dependence are compared with quadrupole relaxation measurements of Riegel et al. and Kerlin et al. in liquid gallium. Agreement is found only with the data of Riegel et al. (orig.) [de

  8. Anomalous behavior of secondary dielectric relaxation in polypropylene glycols

    Energy Technology Data Exchange (ETDEWEB)

    Grzybowska, K; Grzybowski, A; Ziolo, J; Rzoska, S J; Paluch, M [Institute of Physics, Silesian University, Uniwersytecka 4, 40-007 Katowice (Poland)

    2007-09-19

    A surprising slow down in the dielectric secondary {gamma}-relaxation with temperature increasing near the glass transition is confirmed for several polypropylene glycols. The peculiar behavior diminishes as the molecular weight grows. The minimal model (Dyre and Olsen 2003 Phys. Rev. Lett. 91 155703) is applied successfully to describe the temperature dependences of the {gamma}-relaxation times. The minimal model parameters are analyzed for different molecular weights. A molecular explanation of the {gamma}-process anomaly for polypropylene glycols is proposed on the basis of the minimal model prediction.

  9. Low temperature dielectric relaxation and charged defects in ferroelectric thin films

    Directory of Open Access Journals (Sweden)

    A. Artemenko

    2013-04-01

    Full Text Available We report a dielectric relaxation in BaTiO3-based ferroelectric thin films of different composition and with several growth modes: sputtering (with and without magnetron and sol-gel. The relaxation was observed at cryogenic temperatures (T < 100 K for frequencies from 100 Hz up to 10 MHz. This relaxation activation energy is always lower than 200 meV and is very similar to the relaxation that we reported in the parent bulk perovskites. Based on our Electron Paramagnetic Resonance (EPR investigation, we ascribe this dielectric relaxation to the hopping of electrons among Ti3+-V(O charged defects. Being dependent on the growth process and on the amount of oxygen vacancies, this relaxation can be a useful probe of defects in actual integrated capacitors with no need for specific shaping.

  10. Relaxation Techniques to Manage IBS Symptoms

    Science.gov (United States)

    ... for 15–20 seconds and then begin again. Progressive Muscle Relaxation This method of relaxation focuses on ... helpful, please consider supporting IFFGD with a small tax- deductible donation. Make Donation Adapted from IFFGD Publication # ...

  11. Relaxation and Distraction in Experimental Desensitization.

    Science.gov (United States)

    Weir, R. O.; Marshall, W. L.

    1980-01-01

    Compared experimental desensitization with a procedure that replaced relaxation with a distraction task and with an approach that combined both relaxation and distraction. Desensitization generally was more effective than the other two procedures. (Author)

  12. Relaxation as a Factor in Semantic Desensitization

    Science.gov (United States)

    Bechtel, James E.; McNamara, J. Regis

    1975-01-01

    Relaxation and semantic desensitization were used to alleviate the fear of phobic females. Results showed that semantic desensitization, alone or in combination with relaxation, failed to modify the evaluative meanings evoked by the feared object. (SE)

  13. Hydrodynamic relaxations in dissipative particle dynamics

    Science.gov (United States)

    Hansen, J. S.; Greenfield, Michael L.; Dyre, Jeppe C.

    2018-01-01

    This paper studies the dynamics of relaxation phenomena in the standard dissipative particle dynamics (DPD) model [R. D. Groot and P. B. Warren, J. Chem. Phys. 107, 4423 (1997)]. Using fluctuating hydrodynamics as the framework of the investigation, we focus on the collective transverse and longitudinal dynamics. It is shown that classical hydrodynamic theory predicts the transverse dynamics at relatively low temperatures very well when compared to simulation data; however, the theory predictions are, on the same length scale, less accurate for higher temperatures. The agreement with hydrodynamics depends on the definition of the viscosity, and here we find that the transverse dynamics are independent of the dissipative and random shear force contributions to the stress. For high temperatures, the spectrum for the longitudinal dynamics is dominated by the Brillouin peak for large length scales and the relaxation is therefore governed by sound wave propagation and is athermal. This contrasts the results at lower temperatures and small length scale, where the thermal process is clearly present in the spectra. The DPD model, at least qualitatively, re-captures the underlying hydrodynamical mechanisms, and quantitative agreement is excellent at intermediate temperatures for the transverse dynamics.

  14. A study of vibrational relaxation of electronically-excited molecules

    International Nuclear Information System (INIS)

    Datsyuk, V.V.; Izmailov, I.A.; Kochelap, V.A.

    1992-09-01

    The time kinetics of the vibrational relaxation of excimers is studied in the diffusional approximation. Simple formulae for functions of nonstationary vibrational distribution are found for the electronically excited molecules. Some spectral-kinetic dependencies of the excimer luminescence are explained in a new way. The possibilities of the determination of excimer parameters are discussed. The dependence of energetical characteristics of excimer lasers on these parameters is particularly emphasized. (author). 22 refs, 5 figs

  15. Relaxation model of radiation-induced conductivity in polymers

    Science.gov (United States)

    Zhutayeva, Yu. R.; Khatipov, S. A.

    1999-05-01

    The paper suggests a relaxation model of radiation-induced conductivity (RIC) in polymers. According to the model, the transfer of charges generated in the polymer volume by ionizing radiation takes place with the participation of molecular relaxation processes. The mechanism of electron transport consists in the transfer of the charge directly between traps when they draw close to one another due to the rotation of macromolecule segments. The numerical solutions of the corresponding kinetic equations for different distribution functions Q( τ) of the times of molecular relaxation and for different functions of the probability P( τ, τ') of charge transfer in the `overlapping' regions of the diffusion spheres of the segments are analyzed. The relaxation model provides an explanation of the non-Arrhenius behavior of the RIC temperature dependence, the power dependence of RIC on the dose rate with a power index in the interval 0.5-1.0, the appearance of maxima in the curves of the RIC temporal dependence and their irreversible character in the region of large dose rates (more than 1 Gy/s). The model can be used for interpreting polymer RIC in conditions of kinetic mobility of macromolecules.

  16. Nonlinear Relaxation in Population Dynamics

    Science.gov (United States)

    Cirone, Markus A.; de Pasquale, Ferdinando; Spagnolo, Bernardo

    We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the ith population and on the distribution of the population and of the local field.

  17. Structural relaxation: low temperature properties

    International Nuclear Information System (INIS)

    Cruz, F. de la

    1984-01-01

    We discuss the changes in transport and superconducting properties of amorphous Zr 70 Cu 30 , induced by thermal relaxation. The experimental results are used to investigate the relation between the microscopic parameters and the observed physical properties. It is shown that the density of eletronic states determines the shift Tc as well as the variation of the electrical resistivity. It is necessary to assume strong hybridization between s and d bands to understand the eletrodynamic response of the superconductor. (Author) [pt

  18. Nuclear magnetic relaxation in picolines solutions in carbon tetrachloride

    International Nuclear Information System (INIS)

    Jurga, J.; Pajak, Z.; Jurga, K.; Jurga, S.

    1973-01-01

    Spin-lattice relaxation times of the ring and CH 3 group have been measured in order to establish the temperature dependence of the longitudinal relaxation times for picolins in carbon tetrachloride solutions. The information concerning the intramolecular contribution to the relaxation times have been obtained. The high resolution NPR spectrometer operating at 25 MHz has been used. The measurements have been performed in the temperature range from -60degC to 80degC. The experimental results are compared to the predictions given by the Nora Hill and Debye models and it has been found that the Nora Hill model fits the experimental data better than the Debye model. (S.B.)

  19. The Effects of Suggestibility on Relaxation.

    Science.gov (United States)

    Rickard, Henry C.; And Others

    1985-01-01

    Selected undergraduates (N=32) on the basis of Creative Imagination Scale scores and randomly assigned high and low suggestibility subjects to progressive relaxation (PR) and suggestions of relaxation (SR) training modes. Results revealed a significant pre-post relaxation effect, and main efffects for both suggestibility and training mode. (NRB)

  20. Relaxed Poisson cure rate models.

    Science.gov (United States)

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Arresting relaxation in Pickering Emulsions

    Science.gov (United States)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  2. Vibrational relaxation in OCS mixtures

    International Nuclear Information System (INIS)

    Simpson, C.J.S.M.; Gait, P.D.; Simmie, J.M.

    1976-01-01

    Experimental measurements are reported of vibrational relaxation times which may be used to show whether there is near resonant vibration-rotation energy transfer between OCS and H 2 , D 2 or HD. Vibrational relaxation times have been measured in OCS and OCS mixtures over the temperature range 360 to 1000 K using a shock tube and a laser schlieren system. The effectiveness of the additives in reducing the relaxation time of OCS is in the order 4 He 3 He 2 2 and HD. Along this series the effect of an increase in temperature changes from the case of speeding up the rate with 4 He to retarding it with D 2 , HD and H 2 . There is no measurable difference in the effectiveness of n-D 2 and o-D 2 and little, or no, difference between n-H 2 and p-H 2 . Thus the experimental results do not give clear evidence for rotational-vibration energy transfer between hydrogen and OCS. This contrasts with the situation for CO 2 + H 2 mixtures. (author)

  3. Regularized Label Relaxation Linear Regression.

    Science.gov (United States)

    Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

    2018-04-01

    Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

  4. Effect of iodine impurity on relaxation of photoexcited silver chloride

    International Nuclear Information System (INIS)

    Vostrikova, Yu. V.; Klyuev, V. G.

    2008-01-01

    The time and temperature dependences of relaxation of excited AgCl and AgCl:I crystals is studied by the method of photostimulated flash of luminescence. The presence of iodine impurity in silver chloride gives rise to hole recombination (luminescence) centers and hole traps in the band gap. It is shown that the main contribution to the decrease in the concentration of electrons localized at deep traps is made by the recombination of electrons with holes released thermally from shallow localization levels (iodine-related centers). Estimation of activation energy for the relaxation process showed that these energies for the AgCl and AgCl:I samples under study are the same within the experimental error and are equal to E rel1 = 0.01 ± 0.0005 eV for the initial stage of relaxation and E rel2 = 0.09 ± 0.005 eV for the final state. This fact indicates that the majority of hole traps involved in the relaxation process in AgCl are related to iodine impurity. In the course of thermal relaxation in AgCl, relocalization of nonequilibrium charge carriers from shallow levels to deep levels is observed. The depth of the corresponding trap is E arl = 0.174 ± 0.03 eV.

  5. Thermally induced magnetic relaxation in square artificial spin ice

    Science.gov (United States)

    Andersson, M. S.; Pappas, S. D.; Stopfel, H.; Östman, E.; Stein, A.; Nordblad, P.; Mathieu, R.; Hjörvarsson, B.; Kapaklis, V.

    2016-11-01

    The properties of natural and artificial assemblies of interacting elements, ranging from Quarks to Galaxies, are at the heart of Physics. The collective response and dynamics of such assemblies are dictated by the intrinsic dynamical properties of the building blocks, the nature of their interactions and topological constraints. Here we report on the relaxation dynamics of the magnetization of artificial assemblies of mesoscopic spins. In our model nano-magnetic system - square artificial spin ice - we are able to control the geometrical arrangement and interaction strength between the magnetically interacting building blocks by means of nano-lithography. Using time resolved magnetometry we show that the relaxation process can be described using the Kohlrausch law and that the extracted temperature dependent relaxation times of the assemblies follow the Vogel-Fulcher law. The results provide insight into the relaxation dynamics of mesoscopic nano-magnetic model systems, with adjustable energy and time scales, and demonstrates that these can serve as an ideal playground for the studies of collective dynamics and relaxations.

  6. Nuclear magnetic relaxation of methyl group in liquids

    International Nuclear Information System (INIS)

    Blicharska, B.

    1986-01-01

    The theoretical description of the relaxation process of methyl group in liquids and some results of the measurements of relaxation function and relaxation times for cryoprotective solutions are presented. Starting from the application of the operator formalism the general equation for spin operators e.g. components of the nuclear spin and magnetization is founded. Next, the spin Hamiltonian is presented as contraction of the symmetry adapted spherical tensors as well as the correlation functions and spectral densities. On the basis of extended and modified Woessner model of motion the correlation functions and spectral densities are calculated for methyl group in liquids. Using these functions the relaxation matrix elements, the spin-spin and spin-lattice relaxation times can be expressed. The prediction of the theory agrees with author's previous experiments on cryoprotective solutions. The observed dependence on temperature, frequency and isotopic dilution in methanol-water, methanol-dimethyl sulfoxide (DMSO) and DMSO-water solutions is in a satisfactory agreement with theoretical equations. 34 refs. (author)

  7. Magnetic-relaxation method of analysis of inorganic substances

    International Nuclear Information System (INIS)

    Popel', A.A.

    1978-01-01

    The magnetic-relaxation method is considered of the quantitative analysis of inorganic substances based on time dependence of magnetic nuclei relaxation on the quantity of paramagnetic centres in a solution. The characteristic is given of some methods of measuring nuclear magnetic relaxation times: method of weak oscillation generator and pulse methods. The effect of temperature, general solution viscosity, diamagnetic salt concentration, medium acidity on nuclear relaxation velocity is described. The determination sensitivity is estimated and the means of its increase definable concentration intervals and method selectivity are considered. The method application when studying complexing in the solution is described. A particular attention is given to the investigation of heteroligand homocentre, heterocentre and protonated complexes as well as to the problems of particle exchange of the first coordination sphere with particles from the mass of solution. The equations for equilibrium constant calculation in different systems are given. Possibilities of determining diamagnetic ions by the magnetic-relaxation method using paramagnetic indicators are confirmed by the quantitative analysis of indium, gallium, thorium and scandium in their salt solutions

  8. Adaptive under relaxation factor of MATRA code for the efficient whole core analysis

    International Nuclear Information System (INIS)

    Kwon, Hyuk; Kim, S. J.; Seo, K. W.; Hwang, D. H.

    2013-01-01

    Such nonlinearities are handled in MATRA code using outer iteration with Picard scheme. The Picard scheme involves successive updating of the coefficient matrix based on the previously calculated values. The scheme is a simple and effective method for the nonlinear problem but the effectiveness greatly depends on the under-relaxing capability. Accuracy and speed of calculation are very sensitively dependent on the under-relaxation factor in outer-iteration updating the axial mass flow using the continuity equation. The under-relaxation factor in MATRA is generally utilized with a fixed value that is empirically determined. Adapting the under-relaxation factor to the outer iteration is expected to improve the calculation effectiveness of MATRA code rather than calculation with the fixed under-relaxation factor. The present study describes the implementation of adaptive under-relaxation within the subchannel code MATRA. Picard iterations with adaptive under-relaxation can accelerate the convergence for mass conservation in subchannel code MATRA. The most efficient approach for adaptive under relaxation appears to be very problem dependent

  9. Motional spin relaxation in photoexcited triplet states

    International Nuclear Information System (INIS)

    Harryvan, D.; Faassen, E. van

    1997-01-01

    Transient EPR experiments were performed on photoexcited spin triplet states of the luminescent dye EOSIN-Y in diluted (order of 1 nMol) frozen propane-1-ol solutions at various temperatures. Photoexcitation was achieved by irradiation with intense, short laser pulses. The details of the spin relaxation, in particular the dependence on time, magnetic field and microwave field strength are all reproduced by a model which computes the total magnetization in a population of photoexcited triplet states undergoing random reorientational motion. Using this model, we estimated the motional correlation times to be around a microsecond. This timescale is two orders of magnitude slower than the phase memory time of the triplets. (author)

  10. Sandpile model for relaxation in complex systems

    International Nuclear Information System (INIS)

    Vazquez, A.; Sotolongo-Costa, O.; Brouers, F.

    1997-10-01

    The relaxation in complex systems is, in general, nonexponential. After an initial rapid decay the system relaxes slowly following a long time tail. In the present paper a sandpile moderation of the relaxation in complex systems is analysed. Complexity is introduced by a process of avalanches in the Bethe lattice and a feedback mechanism which leads to slower decay with increasing time. In this way, some features of relaxation in complex systems: long time tails relaxation, aging, and fractal distribution of characteristic times, are obtained by simple computer simulations. (author)

  11. Isolation of acetogenic bacteria that induce biocorrosion by utilizing metallic iron as the sole electron donor.

    Science.gov (United States)

    Kato, Souichiro; Yumoto, Isao; Kamagata, Yoichi

    2015-01-01

    Corrosion of iron occurring under anoxic conditions, which is termed microbiologically influenced corrosion (MIC) or biocorrosion, is mostly caused by microbial activities. Microbial activity that enhances corrosion via uptake of electrons from metallic iron [Fe(0)] has been regarded as one of the major causative factors. In addition to sulfate-reducing bacteria and methanogenic archaea in marine environments, acetogenic bacteria in freshwater environments have recently been suggested to cause MIC under anoxic conditions. However, no microorganisms that perform acetogenesis-dependent MIC have been isolated or had their MIC-inducing mechanisms characterized. Here, we enriched and isolated acetogenic bacteria that induce iron corrosion by utilizing Fe(0) as the sole electron donor under freshwater, sulfate-free, and anoxic conditions. The enriched communities produced significantly larger amounts of Fe(II) than the abiotic controls and produced acetate coupled with Fe(0) oxidation prior to CH4 production. Microbial community analysis revealed that Sporomusa sp. and Desulfovibrio sp. dominated in the enrichments. Strain GT1, which is closely related to the acetogen Sporomusa sphaeroides, was eventually isolated from the enrichment. Strain GT1 grew acetogenetically with Fe(0) as the sole electron donor and enhanced iron corrosion, which is the first demonstration of MIC mediated by a pure culture of an acetogen. Other well-known acetogenic bacteria, including Sporomusa ovata and Acetobacterium spp., did not grow well on Fe(0). These results indicate that very few species of acetogens have specific mechanisms to efficiently utilize cathodic electrons derived from Fe(0) oxidation and induce iron corrosion. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Effect of rocker-soled shoes on parameters of knee joint load in knee osteoarthritis.

    Science.gov (United States)

    Madden, Elizabeth G; Kean, Crystal O; Wrigley, Tim V; Bennell, Kim L; Hinman, Rana S

    2015-01-01

    This study evaluated the immediate effects of rocker-soled shoes on parameters of the knee adduction moment (KAM) and pain in individuals with knee osteoarthritis (OA). Three-dimensional gait analysis was performed on 30 individuals (mean (SD): age, 61 (7) yr; 15 (50%) male) with radiographic and symptomatic knee OA under three walking conditions in a randomized order: i) wearing rocker-soled shoes (Skechers Shape-ups), ii) wearing non-rocker-soled shoes (ASICS walking shoes), and iii) barefoot. Peak KAM and KAM angular impulse were measured as primary indicators of knee load distribution. Secondary measures included the knee flexion moment (KFM) and knee pain during walking. Peak KAM was significantly lower when wearing the rocker-soled shoes compared with that when wearing the non-rocker-soled shoes (mean difference (95% confidence interval), -0.27 (-0.42 to -0.12) N·m/BW × Ht%; P < 0.001). Post hoc tests revealed no significant difference in KAM impulse between rocker-soled and non-rocker-soled shoe conditions (P = 0.13). Both peak KAM and KAM impulse were significantly higher during both shoe conditions compared with those during the barefoot condition (P < 0.001). There were no significant differences in KFM (P = 0.36) or knee pain (P = 0.89) between conditions. Rocker-soled shoes significantly reduced peak KAM when compared with non-rocker-soled shoes, without a concomitant change in KFM, and thus may potentially reduce medial knee joint loading. However, KAM parameters in the rocker-soled shoes remained significantly higher than those during barefoot walking. Wearing rocker-soled shoes did not have a significant immediate effect on walking pain. Further research is required to evaluate whether rocker-soled shoes can influence symptoms and progression of knee OA with prolonged wear.

  13. The relationships between suggestibility, influenceability, and relaxability.

    Science.gov (United States)

    Polczyk, Romuald; Frey, Olga; Szpitalak, Malwina

    2013-01-01

    This research explores the relationships between relaxability and various aspects of suggestibility and influenceability. The Jacobson Progressive Muscle Relaxation procedure was used to induce relaxation. Tests of direct suggestibility, relating to the susceptibility of overt suggestions, and indirect suggestibility, referring to indirect hidden influence, as well as self-description questionnaires on suggestibility and the tendency to comply were used. Thayer's Activation-Deactivation Adjective Check List, measuring various kinds of activation and used as a pre- and posttest, determined the efficacy of the relaxation procedure. Indirect, direct, and self-measured suggestibility proved to be positively related to the ability to relax, measured by Thayer's subscales relating to emotions. Compliance was not related to relaxability. The results are discussed in terms of the aspects of relaxation training connected with suggestibility.

  14. A New Vogel-Like Law: Ionic Conductivity, Dielectric Relaxation and Viscosity Near the Glass Transition

    National Research Council Canada - National Science Library

    Bendler, John

    2001-01-01

    A model, based on defect diffusion, is developed that describes temperature and pressure dependence of dielectric relaxation, ionic conductivity and viscosity of glass-forming liquids near the glass...

  15. Dielectric and mechanical relaxation in isooctylcyanobiphenyl (8*OCB)

    Energy Technology Data Exchange (ETDEWEB)

    Pawlus, S; Mierzwa, M; Paluch, M; Rzoska, S J [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Roland, C M, E-mail: michal.mierzwa@us.edu.p [Chemistry Division, Naval Research Laboratory, Code 6120, Washington, DC 20375-5342 (United States)

    2010-06-16

    The dynamics of isooctylcyanobiphenyl (8*OCB) was characterized using dielectric and mechanical spectroscopies. This isomer of the liquid crystalline octylcyanobiphenyl (8OCB) vitrifies during cooling or on application of pressure, exhibiting the typical features of glass-forming liquids: non-Debye relaxation function, non-Arrhenius temperature dependence of the relaxation times, {tau}{sub {alpha}}, a dynamic crossover at T {approx} 1.6T{sub g}. This crossover is evidenced by changes in the behavior of both the peak shape and the temperature dependence of {tau}{sub {alpha}}. The primary relaxation time at the crossover, 2 ns at ambient pressure, is the smallest value reported to date for any molecular liquid or polymer. Interestingly, at all temperatures below this crossover, {tau}{sub {alpha}}and the dc conductivity remain coupled (i.e., conform to the Debye-Stokes-Einstein relation). Two secondary relaxations are observed in the glassy state, one of which is identified as the Johari-Goldstein process. Unlike the case for 8OCB, no liquid crystalline phase could be attained for 8*OCB, demonstrating that relatively small differences in chemical structure can effect substantial changes in the intermolecular potential.

  16. (-)-Epicatechin-induced relaxation of isolated human saphenous vein: Roles of K+ and Ca2+ channels.

    Science.gov (United States)

    Marinko, Marija; Jankovic, Goran; Nenezic, Dragoslav; Milojevic, Predrag; Stojanovic, Ivan; Kanjuh, Vladimir; Novakovic, Aleksandra

    2018-02-01

    In this study, we aimed to investigate relaxant effect of flavanol (-)-epicatechin on the isolated human saphenous vein (HSV), as a part of its cardioprotective action, and to define the mechanisms underlying this vasorelaxation. (-)-Epicatechin induced a concentration-dependent relaxation of HSV pre-contracted by phenylephrine. Among K + channel blockers, 4-aminopyridine, margatoxin, and iberiotoxin significantly inhibited relaxation of HSV, while glibenclamide considerably reduced effects of the high concentrations of (-)-epicatechin. Additionally, (-)-epicatechin relaxed contraction induced by 80 mM K + , whereas in the presence of nifedipine produced partial relaxation of HSV rings pre-contracted by phenylephrine. In Ca 2+ -free solution, (-)-epicatechin relaxed contraction induced by phenylephrine, but had no effect on contraction induced by caffeine. A sarcoplasmic reticulum Ca 2+ -ATPase inhibitor, thapsigargin, significantly reduced relaxation of HSV produced by (-)-epicatechin. These results demonstrate that (-)-epicatechin produces endothelium-independent relaxation of isolated HSV rings. Vasorelaxation to (-)-epicatechin probably involves activation of 4-aminopyridine- and margatoxin-sensitive K V channels, BK Ca channels, and at least partly, K ATP channels. In addition, not only the inhibition of extracellular Ca 2+ influx, but regulation of the intracellular Ca 2+ release, via inositol-trisphosphate receptors and reuptake into sarcoplasmic reticulum, via stimulation of Ca 2+ -ATPase, as well, most likely participate in (-)-epicatechin-induced relaxation of HSV. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  18. Aging of the Johari-Goldstein relaxation in the glass-forming liquids sorbitol and xylitol

    Science.gov (United States)

    Yardimci, Hasan; Leheny, Robert L.

    2006-06-01

    Employing frequency-dependent dielectric susceptibility we characterize the aging in two supercooled liquids, sorbitol and xylitol, below their calorimetric glass transition temperatures. In addition to the alpha relaxation that tracks the structural dynamics, the susceptibility of both liquids possesses a secondary Johari-Goldstein relaxation at higher frequencies. Following a quench through the glass transition, the susceptibility slowly approaches the equilibrium behavior. For both liquids, the magnitude of the Johari-Goldstein relaxation displays a dependence on the time since the quench, or aging time, that is quantitatively very similar to the age dependence of the alpha peak frequency. The Johari-Goldstein relaxation time remains constant during aging for sorbitol while it decreases slightly with age for xylitol. Hence, one cannot sensibly assign a fictive temperature to the Johari-Goldstein relaxation. This behavior contrasts with that of liquids lacking distinct Johari-Goldstein peaks for which the excess wing of the alpha peak tracks the main part of the peak during aging, enabling the assignment of a single fictive temperature to the entire spectrum. The aging behavior of the Johari-Goldstein relaxation time further calls into question the possibility that the relaxation time possesses stronger temperature dependence in equilibrium than is observed in the out-of-equilibrium state below the glass transition.

  19. Relaxation response of A533B steel from 25 to 600/degree/C

    International Nuclear Information System (INIS)

    Swindeman, R.W.; Bolling, E.

    1989-01-01

    Relaxation tests were performed on A533B steel over the range 25 to 600/degree/C in order to examine the general features of time- dependent deformation. It was found that the relaxation strength increased with the flow stress at low temperatures and was relatively independent of history at high temperatures. In the temperature range 400 to 600/degree/C the inelastic strain rates calculated from the relaxation rates followed stress dependencies that were consistent with expectations based on a model proposed by Hart and coworkers for matrix deformation. 21 refs., 10 figs

  20. Correlation of carrier localization with relaxation time distribution and electrical conductivity relaxation in silver-nanoparticle-embedded moderately doped polypyrrole nanostructures

    Science.gov (United States)

    Biswas, Swarup; Dutta, Bula; Bhattacharya, Subhratanu

    2014-02-01

    The electrical conductivity relaxation in moderately doped polypyrrole and its nanocomposites reinforced with different proportion of silver nanoparticles was investigated in both frequency and time domain. An analytical distribution function of relaxation times is constructed from the results obtained in the frequency domain formalism and is used to evaluate the Kohlrausch-Williams-Watts (KWW) type decay function in the time domain. The thermal evolution of different relaxation parameters was analyzed. The temperature-dependent dc electrical conductivity, estimated from the average conductivity relaxation time is observed to depend strongly on the nanoparticle loading and follows Mott three-dimensional variable range hopping (VRH) conduction mechanism. The extent of charge carrier localization calculated from the VRH mechanism is well correlated to the evidences obtained from the structural characterizations of different nanostructured samples.

  1. Thermodynamic scaling of α-relaxation time and viscosity stems from the Johari-Goldstein β-relaxation or the primitive relaxation of the coupling model.

    Science.gov (United States)

    Ngai, K L; Habasaki, J; Prevosto, D; Capaccioli, S; Paluch, Marian

    2012-07-21

    By now it is well established that the structural α-relaxation time, τ(α), of non-associated small molecular and polymeric glass-formers obey thermodynamic scaling. In other words, τ(α) is a function Φ of the product variable, ρ(γ)/T, where ρ is the density and T the temperature. The constant γ as well as the function, τ(α) = Φ(ρ(γ)/T), is material dependent. Actually this dependence of τ(α) on ρ(γ)/T originates from the dependence on the same product variable of the Johari-Goldstein β-relaxation time, τ(β), or the primitive relaxation time, τ(0), of the coupling model. To support this assertion, we give evidences from various sources itemized as follows. (1) The invariance of the relation between τ(α) and τ(β) or τ(0) to widely different combinations of pressure and temperature. (2) Experimental dielectric and viscosity data of glass-forming van der Waals liquids and polymer. (3) Molecular dynamics simulations of binary Lennard-Jones (LJ) models, the Lewis-Wahnström model of ortho-terphenyl, 1,4 polybutadiene, a room temperature ionic liquid, 1-ethyl-3-methylimidazolium nitrate, and a molten salt 2Ca(NO(3))(2)·3KNO(3) (CKN). (4) Both diffusivity and structural relaxation time, as well as the breakdown of Stokes-Einstein relation in CKN obey thermodynamic scaling by ρ(γ)/T with the same γ. (5) In polymers, the chain normal mode relaxation time, τ(N), is another function of ρ(γ)/T with the same γ as segmental relaxation time τ(α). (6) While the data of τ(α) from simulations for the full LJ binary mixture obey very well the thermodynamic scaling, it is strongly violated when the LJ interaction potential is truncated beyond typical inter-particle distance, although in both cases the repulsive pair potentials coincide for some distances.

  2. Legumes and forage species sole or intercropped with corn in soybean-corn succession in midwestern Brazil

    Directory of Open Access Journals (Sweden)

    Gessí Ceccon

    2013-02-01

    Full Text Available The feasibility of no-tillage in the Cerrado (Savanna-like vegetation of Brazil depends on the production of sufficient above-ground crop residue, which can be increased by corn-forage intercropping. This study evaluated how above-ground crop residue production and yields of soybean and late-season corn in a soybean-corn rotation were influenced by the following crops in the year before soybean: corn (Zea mays L. intercropped with Brachiaria (Urochloa brizantha cv. Marandu, B. decumbens cv. Basilisk, B. ruziziensis, cv. comum., Panicummaximum cv. Tanzânia, sunn hemp (Crotalaria juncea L., pigeon pea [Cajanus cajan (L. Millsp]; sole corn, forage sorghum [Sorghum bicolor (L. Moench (cv. Santa Elisa], and ruzi grass. In March 2005, corn and forage species were planted in alternate rows spaced 0.90 m apart, and sole forage species were planted in rows spaced 0.45 m apart. In October 2005, the forages were killed with glyphosate and soybean was planted. After the soybean harvest in March 2006, sole late-season corn was planted in the entire experimental area. Corn grain and stover yields were unaffected by intercropping. Above-ground crop residue was greater when corn was intercropped with Tanzania grass (10.7 Mg ha-1, Marandu (10.1 Mg ha-1, and Ruzi Grass (9.8 Mg ha-1 than when corn was not intercropped (4.0 Mg ha-1. The intercropped treatments increased the percentage of soil surface covered with crop residue. Soybean and corn grain yields were higher after sole ruzi grass and intercropped ruzi grass than after other crops. The intercropping corn with Brachiaria spp. and corn with Panicum spp. increases above-ground crop residue production and maintains nutrients in the soil without reducing late-season corn yield and the viability of no-till in the midwestern region of Brazil.

  3. An in situ study of the enhancement of atomic mobility under neutron irradiation in a Ag-30at%Zn alloy, using the Zener relaxation

    International Nuclear Information System (INIS)

    Halbwachs, M.; Hillairet, J.; Gonzalez, H.; Cost, J.

    1975-01-01

    An application of the Zener relaxation to the study of fast neutron effects on a Ag-Zn alloy is presented. The temperature dependence of the relaxation time is shown. It can be seen that the measured relaxation time at a given temperature increases with the irradiation doses [fr

  4. Ultrasonic relaxations in borate glasses

    International Nuclear Information System (INIS)

    D'Angelo, G.; Tripodo, G.; Carini, G.; Cosio, E.; Bartolotta, A.; Di Marco, G.

    2004-01-01

    The attenuation and velocity of ultrasonic waves of frequencies in the range from 10 to 70 MHz have been measured in M 2 O-B 2 O 3 borate glasses (M: Li or Ag) as a function of temperature between 15 and 350 K. The velocity of sound waves decreases with increasing temperature in all the glasses, the decrease as the temperature is increased is larger in glasses containing silver than in those with lithium. A broad relaxation peak characterises the attenuation behaviour of the lithium and silver borate glasses at temperatures below 100 K and is paralleled by a corresponding dispersive behaviour of the sound velocity. Above 100 K, the ultrasonic velocity shows a nearly linear behaviour regulated by the vibrational anharmonicity, which decreases with increasing content of modifier oxide and is smaller in lithium than in silver borates. These results suggest that the relaxation of structural defects and the anharmonicity of borate glasses are strongly affected by two parameters: the number of bridging bonds per network forming ion and the polarising power of network modifier ions which occupy sites in the existing interstices

  5. 75 FR 53269 - Federal Acquisition Regulation; Tribal Consultation; Justification and Approval of Sole-Source 8...

    Science.gov (United States)

    2010-08-31

    ... and approval of sole-source contracts over $20 million under the 8(a) small business development... valuable component of its deliberations in preparing to implement this law, which includes contracting with... Regulation; Tribal Consultation; Justification and Approval of Sole-Source 8(a) Contracts AGENCIES...

  6. Growth performances of juvenile sole Solea solea under environmental constraints of embayed nursery areas

    NARCIS (Netherlands)

    Laffargue, P.; Lagardere, F.; Rijnsdorp, A.D.; Fillon, A.; Amara, R.

    2007-01-01

    Tidal embayments in the Bay of Biscay (France) host nursery grounds where common sole, Solea solea, is the most abundant flatfish species. This study aimed to appraise the way those habitats function as nurseries through juvenile sole's responses in somatic growth and condition (Fulton's K) during

  7. 78 FR 51061 - TRICARE; Reimbursement of Sole Community Hospitals and Adjustment to Reimbursement of Critical...

    Science.gov (United States)

    2013-08-20

    ... DEPARTMENT OF DEFENSE 32 CFR Part 199 [DoD-2010-HA-0072] RIN 0720-AB41 TRICARE; Reimbursement of Sole Community Hospitals and Adjustment to Reimbursement of Critical Access Hospitals; Correction... TRICARE; Reimbursement of Sole Community Hospitals and Adjustment to Reimbursement of Critical Access...

  8. Variation in behaviour and growth of common sole : genetic and environmental influences

    NARCIS (Netherlands)

    Mas Muñoz, J.

    2013-01-01

    Common sole (Solea solea) has a high potential for commercial aquaculture because of its consumer popularity and high market values in Europe. However, a major economic constraint for the culture of sole is its slow and variable growth. The aim of this thesis was to investigate: 1) the

  9. Molecular order and T1-relaxation, cross-relaxation in nitroxide spin labels

    Science.gov (United States)

    Marsh, Derek

    2018-05-01

    Interpretation of saturation-recovery EPR experiments on nitroxide spin labels whose angular rotation is restricted by the orienting potential of the environment (e.g., membranes) currently concentrates on the influence of rotational rates and not of molecular order. Here, I consider the dependence on molecular ordering of contributions to the rates of electron spin-lattice relaxation and cross relaxation from modulation of N-hyperfine and Zeeman anisotropies. These are determined by the averages and , where θ is the angle between the nitroxide z-axis and the static magnetic field, which in turn depends on the angles that these two directions make with the director of uniaxial ordering. For saturation-recovery EPR at 9 GHz, the recovery rate constant is predicted to decrease with increasing order for the magnetic field oriented parallel to the director, and to increase slightly for the perpendicular field orientation. The latter situation corresponds to the usual experimental protocol and is consistent with the dependence on chain-labelling position in lipid bilayer membranes. An altered dependence on order parameter is predicted for saturation-recovery EPR at high field (94 GHz) that is not entirely consistent with observation. Comparisons with experiment are complicated by contributions from slow-motional components, and an unexplained background recovery rate that most probably is independent of order parameter. In general, this analysis supports the interpretation that recovery rates are determined principally by rotational diffusion rates, but experiments at other spectral positions/field orientations could increase the sensitivity to order parameter.

  10. Characterization of structural relaxation in inorganic glasses using length dilatometry

    Science.gov (United States)

    Koontz, Erick

    characterization technique is comprised of three main components: experimental measurements, fitting of configurational length change, and description of glass behavior by analysis of fitting parameters. N-BK7 optical glass from Schott was used as the proof of concept glass but the main scientific interest was in three chalcogenide glasses: As40Se 60, As20Se80, and Ge17.9As19.7 Se62.4. The dilatometric experiments were carried out using a thermomechanical analyzer (TMA) on glass sample that were synthesized by the author, in all cases except N-BK7. Isothermal structural relaxation measurements were done on (12 mm tall x 3 mm x 3 mm) beams placed vertically in the TMA. The samples were equilibrated at a starting temperature (T 0) until structural equilibrium was reached then a temperature down step was initiated to the final temperature (T 1) and held isothermally until relaxation concluded. The configurational aspect of length relaxation, and therefore volume relaxation was extracted and fit with a Prony series. The Prony series parameters indicated a number of relaxation events occurring within the glass on timescales typically an order of magnitude apart in time. The data analysis showed as many as 4 discrete relaxation times at lower temperatures. The number of discrete relaxation decreased as the temperature increased until just one single relaxation was left in the temperature range just at or above Tg. In the case of N-BK7 these trends were utilized to construct a simple model that could be applied to glass manufacturing in the areas of annealing or PGM. A future development of a rather simple finite element model (FEM) would easily be able to use this model to predict the exponential-like, temperature and time dependent relaxation behaviors of the glass. The predictive model was not extended to the chalcogenide glass studied here, but could easily be applied to them in the future. The relaxation time trends versus temperature showed a definite region of transition between a

  11. The comparison of nitrogen use and leaching in sole cropped versus intercropped pea and barley

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Ambus, P.; Jensen, E.S.

    2003-01-01

    The effect of sole and intercropping of field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.) and of crop residue management on crop yield, NO3- leaching and N balance in the cropping system was tested in a 2-year lysimeter experiment on a temperate sandy loam soil. The crop rotation...... cropping. Crops received no fertilizer in the experimental period. Natural N-15 abundance techniques were used to determine pea N-2 fixation. The pea-barley intercrop yielded 4.0 Mg grain ha(-1), which was about 0.5 Mg lower than the yields of sole cropped pea but about 1.5 Mg greater than harvested...... was pea and barley sole and intercrops followed by winter-rye and a fallow period. The Land Equivalent Ratio (LER), which is defined as the relative land area under sole crops that is required to produce the yields achieved in intercropping, was used to compare intercropping performance relative to sole...

  12. Paramagnetic relaxation effects in perturbed angular correlations for arbitrary electronic relaxation time

    International Nuclear Information System (INIS)

    Chopin, C.; Spanjaard, D.; Hartmann-Boutron, F.

    1975-01-01

    Previous perturbation treatments of paramagnetic relaxation effects in γγ PAC were limited to the case of very short electronic relaxation times. This limitation is circumvented by invoking a new perturbation theory recently elaborated by Hirst and others for handling relaxation effects in Moessbauer spectra. Under the assumption of spherical electronic relaxation the perturbation factors are computed as functions of certain relaxation parameters which are directly related to the microscopic relaxation Hamiltonian. The results are compared to those of the stochastic theory of Scherer and Blume [fr

  13. Temperature relaxation in collisional non equilibrium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Potapenko, I.F.; Bobylev, A.V.; Azevedo, C.A.; Assis, A.S. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica

    1997-12-31

    Full text. We study the relaxation of a space uniform plasma composed of electrons and one species of ions. To simplified the consideration, standard approach is usually accepted: the distribution functions are considered to be a Maxwellian with time dependent electron T{sub e}(t) and ion T{sub i}(t) temperatures. This approach imposes a severe restriction on the electron/ion distributions that could be very far from the equilibrium. In the present work the problem is investigated on the basis of the nonlinear kinetic Fokker - Planck equation, which is widely used for the description of collisional plasmas. This equation has many applications in plasma physics as an intrinsic part of physical models, both analytical and numerical. A new detailed description of this classical problem of the collisional plasma kinetic theory is given. A deeper examination of the problem shows that the unusual perturbation theory can not be used. The part of the perturbation of the electron distribution has the character of a boundary layer in the neighborhood of small velocities. In this work the boundary layer is thoroughly studied. The correct distribution electron function is given. Nonmonotonic character of the distribution relaxation in the tail region is observed. The corrected formula for temperature equalization is obtained. The comparison of the calculation results with the asymptotic approach is made. We should stress the important role of the completely conservative different scheme used here, which keeps the symmetric properties of the nonlinear exact equation. This allows us to make calculations without numerical error accumulations, except for machine errors. (author)

  14. Vibrational energy transfer in selectively excited diatomic molecules. [Relaxation rates, self-relaxation, upper limits

    Energy Technology Data Exchange (ETDEWEB)

    Dasch, C.J.

    1978-09-01

    Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.

  15. Longitudinal relaxation of initially straight flexible and stiff polymers

    Science.gov (United States)

    Dimitrakopoulos, Panagiotis; Dissanayake, Inuka

    2004-11-01

    The present talk considers the relaxation of a single flexible or stiff polymer chain from an initial straight configuration in a viscous solvent. This problem commonly arises when strong flows are turned off in both industrial and biological applications. The problem is also motivated by recent experiments with single biopolymer molecules relaxing after being fully extended by applied forces as well as by the recent development of micro-devices involving stretched tethered biopolymers. Our results are applicable to a wide array of synthetic polymers such as polyacrylamides, Kevlar and polyesters as well as biopolymers such as DNA, actin filaments, microtubules and MTV. In this talk we discuss the mechanism of the polymer relaxation as was revealed through Brownian Dynamics simulations covering a broad range of time scales and chain stiffness. After the short-time free diffusion, the chain's longitudinal reduction at early intermediate times is shown to constitute a universal behavior for any chain stiffness caused by a quasi-steady relaxation of tensions associated with the deforming action of the Brownian forces. Stiff chains are shown to exhibit a late intermediate-time longitudinal reduction associated with a relaxation of tensions affected by the deforming Brownian and the restoring bending forces. The longitudinal and transverse relaxations are shown to obey different laws, i.e. the chain relaxation is anisotropic at all times. In the talk, we show how from the knowledge of the relaxation mechanism, we can predict and explain the polymer properties including the polymer stress and the solution birefringence. In addition, a generalized stress-optic law is derived valid for any time and chain stiffness. All polymer properties which depend on the polymer length are shown to exhibit two intermediate-time behaviors with the early one to constitute a universal behavior for any chain stiffness. This work was supported in part by the Minta Martin Research Fund. The

  16. Resonant tunneling measurements of size-induced strain relaxation

    Science.gov (United States)

    Akyuz, Can Deniz

    Lattice mismatch strain available in such semiconductor heterostructures as Si/SiGe or GaAs/AlGaAs can be employed to alter the electronic and optoelectronic properties of semiconductor structures and devices. When deep submicron structures are fabricated from strained material, strained layers relax by sidewall expansion giving rise to size- and geometry-dependent strain gradients throughout the structure. This thesis describes a novel experimental technique to probe the size-induced strain relaxation by studying the tunneling current characteristics of strained p-type Si/SiGe resonant tunneling diodes. Our current-voltage measurements on submicron strained p-Si/SiGe double- and triple-barrier resonant tunneling structures as a function of device diameter, D, provide experimental access to both the average strain relaxation (which leads to relative shifts in the tunneling current peak positions) and strain gradients (which give rise to a fine structure in the current peaks due to inhomogeneous strain-induced lateral quantization). We find that strain relaxation is significant, with a large fraction of the strain energy relaxed on average in D ≤ 0.25 m m devices. Further, the in-plane potentials that arise from inhomogeneous strain gradients are large. In the D ˜ 0.2 m m devices, the corresponding lateral potentials are approximately parabolic exceeding ˜ 25 meV near the perimeter. These potentials create discrete hole states in double-barrier structures (single well), and coupled hole states in triple-barrier structures (two wells). Our results are in excellent agreement with finite-element strain calculations in which the strained layers are permitted to relax to a state of minimum energy by sidewall expansion. Size-induced strain relaxation will undoubtedly become a serious technological issue once strained devices are scaled down to the deep submicron regime. Interestingly, our calculations predict and our measurements are consistent with the appearance of

  17. Effect of radiation and non-Maxwellian electron distribution on relaxation processes in an atmospheric cesium seeded argon plasma

    International Nuclear Information System (INIS)

    Borghi, C.A.; Veefkind, A.; Wetzer, J.M.

    1982-03-01

    A model, describing the time dependent behaviour of a noble gas MHD generator plasma, has been set up. With this model it is possible to calculate the relaxation for ionization or recombination as a response to a stepwise temperature development, once the initial and final conditions are given. In model radiative transitions and a deviation from Maxwellian electron distribution are included. Radiation causes an enhancement of both the ionization relaxation time and the recombination relaxation time. A non-Maxwellian electron distribution results in an increase of the relaxation time for an ionizing plasma because of an underpopulation of the high energy electrons. A decrease of the relaxation time for a recombining plasma is caused by an overpopulation of high energy electrons. The relaxation time is strongly dependent on the seed ratio and the temperature step. (Auth.)

  18. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  19. Dielectric relaxation in Yb-doped SrZrO3

    International Nuclear Information System (INIS)

    Kamishima, O; Abe, Y; Ishii, T; Kawamura, J; Hattori, T

    2004-01-01

    The dielectric constant of the proton conductor SrZr 1-x Yb x O 3 (x 0-0.1) was measured as a function of temperature and frequency. Two well-defined relaxation peaks were observed in SrZrO 3 doped with more than 1 mol% of Yb. The assignment of the two dielectric relaxations is discussed in terms of IR spectra and by free energy calculation for a miscibility of dopant Yb ions. The Yb concentration dependence of the relaxation strength of the two dielectric relaxations is in agreement with the results calculated from the free energy. The two relaxations can be assigned to a reorientation of a single Yb-OH dipole and of Yb-OH dipoles associated with Yb-clusters. The attractive energy for Yb-clustering in SrZrO 3 is evaluated at about -85 meV

  20. Dielectric Relaxation of Water: Theory and Experiment

    International Nuclear Information System (INIS)

    Adhikari, Narayan Prasad; Paudyal, Harihar; Johri, Manoj

    2010-06-01

    We have studied the hydrogen bond dynamics and methods for evaluation of probability and relaxation time for hydrogen bond network. Further, dielectric relaxation time has been calculated by using a diagonalization procedure by obtaining eigen values (inverse of relaxation time) of a master equation framed on the basis of Fokker-Planck equations. Microwave cavity spectrometer has been described to make measurements of relaxation time. Slater's perturbation equations are given for the analysis of the data. A comparison of theoretical and experimental data shows that there is a need for improvements in the theoretical model and experimental techniques to provide exact information about structural properties of water. (author)

  1. Relaxation periodic solutions of one singular perturbed system with delay

    Science.gov (United States)

    Kashchenko, A. A.

    2017-12-01

    In this paper, we consider a singularly perturbed system of two differential equations with delay, simulating two coupled oscillators with a nonlinear compactly supported feedback. We reduce studying nonlocal dynamics of initial system to studying dynamics of special finite-dimensional mappings: rough stable (unstable) cycles of these mappings correspond to exponentially orbitally stable (unstable) relaxation solutions of initial problem. We show that dynamics of initial model depends on coupling coefficient crucially. Multistability is proved.

  2. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  3. Relaxing Chosen-Ciphertext Security

    DEFF Research Database (Denmark)

    Canetti, Ran; Krawczyk, Hugo; Nielsen, Jesper Buus

    2003-01-01

    Security against adaptive chosen ciphertext attacks (or, CCA security) has been accepted as the standard requirement from encryption schemes that need to withstand active attacks. In particular, it is regarded as the appropriate security notion for encryption schemes used as components within...... general protocols and applications. Indeed, CCA security was shown to suffice in a large variety of contexts. However, CCA security often appears to be somewhat too strong: there exist encryption schemes (some of which come up naturally in practice) that are not CCA secure, but seem sufficiently secure...... “for most practical purposes.” We propose a relaxed variant of CCA security, called Replayable CCA (RCCA) security. RCCA security accepts as secure the non-CCA (yet arguably secure) schemes mentioned above; furthermore, it suffices for most existing applications of CCA security. We provide three...

  4. Nuclear relaxation and critical fluctuations in membranes containing cholesterol

    Science.gov (United States)

    McConnell, Harden

    2009-04-01

    Nuclear resonance frequencies in bilayer membranes depend on lipid composition. Our calculations describe the combined effects of composition fluctuations and diffusion on nuclear relaxation near a miscibility critical point. Both tracer and gradient diffusion are included. The calculations involve correlation functions and a correlation length ξ =ξ0T/(T -Tc), where T -Tc is temperature above the critical temperature and ξ0 is a parameter of molecular length. Several correlation functions are examined, each of which is related in some degree to the Ising model correlation function. These correlation functions are used in the calculation of transverse deuterium relaxation rates in magic angle spinning and quadrupole echo experiments. The calculations are compared with experiments that report maxima in deuterium and proton nuclear relaxation rates at the critical temperature [Veatch et al., Proc. Nat. Acad. Sci. U.S.A. 104, 17650 (2007)]. One Ising-model-related correlation function yields a maximum 1/T2 relaxation rate at the critical temperature for both magic angle spinning and quadrupole echo experiments. The calculated rates at the critical temperature are close to the experimental rates. The rate maxima involve relatively rapid tracer diffusion in a static composition gradient over distances of up to 10-100 nm.

  5. Spin-lattice relaxation of individual solid-state spins

    Science.gov (United States)

    Norambuena, A.; Muñoz, E.; Dinani, H. T.; Jarmola, A.; Maletinsky, P.; Budker, D.; Maze, J. R.

    2018-03-01

    Understanding the effect of vibrations on the relaxation process of individual spins is crucial for implementing nanosystems for quantum information and quantum metrology applications. In this work, we present a theoretical microscopic model to describe the spin-lattice relaxation of individual electronic spins associated to negatively charged nitrogen-vacancy centers in diamond, although our results can be extended to other spin-boson systems. Starting from a general spin-lattice interaction Hamiltonian, we provide a detailed description and solution of the quantum master equation of an electronic spin-one system coupled to a phononic bath in thermal equilibrium. Special attention is given to the dynamics of one-phonon processes below 1 K where our results agree with recent experimental findings and analytically describe the temperature and magnetic-field scaling. At higher temperatures, linear and second-order terms in the interaction Hamiltonian are considered and the temperature scaling is discussed for acoustic and quasilocalized phonons when appropriate. Our results, in addition to confirming a T5 temperature dependence of the longitudinal relaxation rate at higher temperatures, in agreement with experimental observations, provide a theoretical background for modeling the spin-lattice relaxation at a wide range of temperatures where different temperature scalings might be expected.

  6. BREATHING EXERCISE RELAXATION INCREASE PHSYCOLOGICAL RESPONSE PRESCHOOL CHILDREN

    Directory of Open Access Journals (Sweden)

    Yuni Sufyanti Arief

    2017-07-01

    Full Text Available Introduction: Being hospitalize will be made the children become stress. Hospitalization response of the child particularly is afraid sense regard to painfull procedure and increase to attack the invasive procedure. The aimed of this study was to describe the influence of breathing exercise relaxation technique regarded to phsycological receiving responses in the preeliminary school chidren while they were receiving invasive procedure. Method: A quasy experimental purposive sampling design was used in this study. There were 20 respondents who met to the inclusion criteria. The independent variable was the breathing exercise relaxation technique and the dependent variable was phsycological receiving responses. Data for phsylogical response were collected by using observation form then analyzed by using Wilcoxon Signed Rank Test and Mann Whitney U Test with significance level α≤0.05. Result :  The result showed that breathing exercise relaxation technique had significance influence to phsycological response (p=0.000. Discussion: It,s can be concluded that breathing exercise relaxation technique has an effect to increase pshycological response in preeliminary school children who received invasive procedure.

  7. Magnon interaction and relaxation in yttrium iron garnet

    International Nuclear Information System (INIS)

    Mukimov, K.M.; Jumaev, M.R.; Kenjaev, Z.M.

    2007-01-01

    Full text: Magnon interaction and relaxation are the fundamental characteristics describing the response of any system to an external AC field. Almost all experiments aimed at magnon excitation have been carried out in the microwave frequency range where only magnons with energies 0.1 - 5 K can be excited. Nevertheless, all magnons with energy lower or order of the temperature are involved in the processes of low energy magnon relaxation. The present study deals with the interactions of magnons in YIG in thermodynamic equilibrium at temperatures up to 300 K. We consider the exchange and magnetic - dipole terms in the YIG Hamiltonian and a term due to the local uniaxial crystallographic anisotropy, find the corresponding amplitudes of three - and four - magnon process, and calculate the relaxation rate and the correction to the ferromagnon frequency to the first order in the interaction. This correction is positive, in contrast to the case of ferromagnets, and it is proportional to at temperatures up to, in agreement with experiment. The exchange - relaxation rate of the magnons is found as a function of the wave vector and temperature. In the region this rate agrees with the familiar expression for ferromagnets. At higher temperatures, at which the main contribution to the exchange damping is from the magnons of the linear part of the spectrum, the temperature dependence of the damping becomes stronger. (authors)

  8. Relaxation path of metastable nanoclusters in oxide dispersion strengthened materials

    Energy Technology Data Exchange (ETDEWEB)

    Ribis, J., E-mail: joel.ribis@cea.fr [DEN-Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Thual, M.A. [LLB, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191, Gif-sur-Yvette (France); Guilbert, T.; Carlan, Y. de [DEN-Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Legris, A. [UMET, CNRS/UMR 8207, Bât. C6, Univ. Lille 1, 59655 Villeneuve d’Ascq (France)

    2017-02-15

    ODS steels are a promising class of structural materials for sodium cooled fast reactor application. The ultra-high density of the strengthening nanoclusters dispersed within the ferritic matrix is responsible of the excellent creep properties of the alloy. Fine characterization of the nanoclusters has been conducted on a Fe-14Cr-0.3Ti-0.3Y{sub 2}O{sub 3} ODS material using High Resolution and Energy Filtered Transmission Electron Microscopy. The nanoclusters exhibit a cubic symmetry possibly identified as f.c.c and display a non-equilibrium YTiCrO chemical composition thought to be stabilized by a vacancy supersaturation. These nanoclusters undergo relaxation towards the Y{sub 2}Ti{sub 2}O{sub 7}-like state as they grow. A Cr shell is observed around the relaxed nano-oxides, this size-dependent shell may form after the release of Cr by the particles. The relaxation energy barrier appears to be higher for the smaller particles probably owing to a volume/surface ratio effect in reason to the full coherency of the nanoclusters. - Highlights: • The nanoclusters display a f.c.c. cubic symmetry and a non-equilibrium YTiCrO chemical composition. • During thermal annealing the coherent nanocluster transform into semi-coherent pyrochlore particles. • A Cr ring is observed around the relaxed pyrochlore type particles.

  9. Transverse magnetic field effects on the relaxation time of the magnetization in Mn12 measured by 55Mn-NMR

    International Nuclear Information System (INIS)

    Furukawa, Y.; Watanabe, K.; Kumagai, K.; Borsa, F.; Gatteschi, D.

    2003-01-01

    The longitudinal (H Z ) and transverse (H T ) magnetic field dependence of the relaxation time of the magnetization in Mn12 in its S=10 ground state was measured by NMR. The minima in the relaxation time at the fields for level crossing are due to the quantum tunneling of the magnetization. The shortening of the relaxation time under the application of H T is shown to be due mainly to the reduction of the energy barrier

  10. Proximal weakness of lower limbs as the sole presentation of hyperthyroidism: report of one case.

    Science.gov (United States)

    Chen, Chu-Chin; Chiu, Pao-Chin; Shih, Chen-Houng; Hsieh, Kai-Sheng

    2005-01-01

    Most children with acute or chronic flaccid limb weakness have a disorder of motor unit. However, it is very important to exclude cerebral or other upper motor neuron disorders before we approach such patients as pure muscle disorders. In general, neuropathy results in distal limb weakness, myopathy manifests with proximal weakness. There are exceptions, however. Accurate diagnosis in this wide array of disorders is dependent on a careful clinical assessment followed by the appropriate investigations. Here we report a 14-year-old girl who presented with progressive difficulty in rising up from the floor for one month. Neurological examination revealed an obese, clumsy but clear girl with stable vital signs. The muscle power of neck and upper limbs was normal. There was positive Gower sign, but the toe and heel gaits were acceptable. The initial blood work and motor/sensory nerve conduction velocity were unremarkable. Further study for thyroid function showed a hyperthyroid state. The proximal myopathy recovered soon after medical treatment. There were no other symptoms, and signs indicating hyperthyroidism and proximal myopathy of lower limbs was the isolated clinical feature. Hyperthyroid myopathy is common in hyperthyroidism, but is unusual as the sole presenting symptom.

  11. Pancreatic Tail Cancer with Sole Manifestation of Left Flank Pain: A Very Rare Presentation

    Directory of Open Access Journals (Sweden)

    Hsing-Lin Lin

    2008-06-01

    Full Text Available Pancreatic cancer is sometimes called a “silent disease” because it often causes no symptoms in the early stage. The symptoms can be quite vague and various depending on the location of cancer in the pancreas. The anatomic site distribution is 78% in the head of the pancreas, 11% in the body, and 11% in the tail. Pancreatic cancer is rarely detected in the early stage, and it is very uncommon to diagnose pancreatic tail cancer during an emergency department visit. The manifestation of pancreatic tail cancer as left flank pain is very rare and has seldom been identified in the literature. We present a case of pancreatic tail cancer with the sole manifestation of dull left flank pain. Having negative findings on an ultrasound study initially, this female patient was misdiagnosed as having possible acute gastritis, urolithiasis or muscle strain after she received gastroendoscopy and colonofiberscopy. Her symptoms persisted for several months and she visited our emergency department due to an acute exacerbation of a persistent dull pain in the left flank area. Radiographic evaluation with computed tomography was performed, and pancreatic tail tumor with multiple metastases was found unexpectedly. We review the literature and discuss this rare presentation of pancreatic tail cancer.

  12. Stress relaxation behavior and mechanism of AEREX350 and Waspaloy superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuzhou; Dong, Jianxin; Zhang, Maicang; Yao, Zhihao

    2016-12-15

    The relaxation properties of AEREX350 and Waspaloy were studied contrastively at temperatures ranging from 600 °C to 800 °C with the same initial stress 510 MPa. The relationship between the microstructure and relaxation properties was elucidated using scanning and transmission electron microscopy techniques. It was found that the relaxation limit and relaxation stability of the two alloys decreased obviously with the increase of temperature, but the relaxation stability of AEREX350 decreased more slowly compared with Waspaloy. Further investigations show that the relaxation behavior is mainly depended on both precipitate characteristics and its interaction with dislocations. The complex precipitates evolution of AEREX350 alloy leads to a higher relaxation limit at high temperature 800 °C, but more quantity of γ′ in Waspaloy results in a higher relaxation limit at the low temperature of 600 °C. Thus it is suggested that as fastener alloys, Waspaloy is more suitable for low temperature service while AEREX350 is the preferred choice for high temperature service.

  13. Glass transition and relaxation dynamics of propylene glycol-water solutions confined in clay

    Science.gov (United States)

    Elamin, Khalid; Björklund, Jimmy; Nyhlén, Fredrik; Yttergren, Madeleine; Mârtensson, Lena; Swenson, Jan

    2014-07-01

    The molecular dynamics of aqueous solutions of propylene glycol (PG) and propylene glycol methylether (PGME) confined in a two-dimensional layer-structured Na-vermiculite clay has been studied by broadband dielectric spectroscopy and differential scanning calorimetry. As typical for liquids in confined geometries the intensity of the cooperative α-relaxation becomes considerably more suppressed than the more local β-like relaxation processes. In fact, at high water contents the calorimetric glass transition and related structural α-relaxation cannot even be observed, due to the confinement. Thus, the intensity of the viscosity related α-relaxation is dramatically reduced, but its time scale as well as the related glass transition temperature Tg are for both systems only weakly influenced by the confinement. In the case of the PGME-water solutions it is an important finding since in the corresponding bulk system a pronounced non-monotonic concentration dependence of the glass transition related dynamics has been observed due to the growth of hydrogen bonded relaxing entities of water bridging between PGME molecules [J. Sjöström, J. Mattsson, R. Bergman, and J. Swenson, Phys. Chem. B 115, 10013 (2011)]. The present results suggest that the same type of structural entities are formed in the quasi-two-dimensional space between the clay platelets. It is also observed that the main water relaxation cannot be distinguished from the β-relaxation of PG or PGME in the concentration range up to intermediate water contents. This suggests that these two processes are coupled and that the water molecules affect the time scale of the β-relaxation. However, this is most likely true also for the corresponding bulk solutions, which exhibit similar time scales of this combined relaxation process below Tg. Finally, it is found that at higher water contents the water relaxation does not merge with, or follow, the α-relaxation above Tg, but instead crosses the α-relaxation

  14. The Effects of Progressive Relaxation and Music on Attention, Relaxation, and Stress Responses: An Investigation of the Cognitive-Behavioral Model of Relaxation

    National Research Council Canada - National Science Library

    Scheufele, Peter

    1999-01-01

    ...) suggested that stress management techniques have specific effects A compromise position suggests that the specific effects of relaxation techniques are superimposed upon a general relaxation response...

  15. Mechanism of resveratrol-induced relaxation of the guinea pig fundus.

    Science.gov (United States)

    Tsai, Ching-Chung; Tey, Shu-Leei; Lee, Ming-Che; Liu, Ching-Wen; Su, Yu-Tsun; Huang, Shih-Che

    2018-04-01

    Resveratrol is a polyphenolic compound that can be isolated from plants and also is a constituent of red wine. Resveratrol induces relaxation of vascular smooth muscle and may prevent cardiovascular diseases. Impaired gastric accommodation plays an important role in functional dyspepsia and fundic relaxation and is a therapeutic target of functional dyspepsia. Although drugs for fundic relaxation have been developed, these types of drugs are still rare. The purpose of this study was to investigate the relaxant effects of resveratrol in the guinea pig fundus. We studied the relaxant effects of resveratrol in the guinea pig fundus. In addition, we investigated the mechanism of resveratrol-induced relaxation on the guinea pig fundus by using tetraethylammonium (a non-selective potassium channel blocker), apamine (a selective inhibitor of the small conductance calcium-activated potassium channel), iberiotoxin (an inhibitor of large conductance calcium-activated potassium channels), glibenclamide (an ATP-sensitive potassium channel blocker), KT 5720 (a cAMP-dependent protein kinase A inhibitor), KT 5823 (a cGMP-dependent protein kinase G inhibitor), NG-nitro-L-arginine (a competitive inhibitor of nitric oxide synthase), tetrodotoxin (a selective neuronal Na + channel blocker), ω-conotoxin GVIA (a selective neuronal Ca 2+ channel blocker) and G-15 (a G-protein coupled estrogen receptor antagonist). The results of this study showed that resveratrol has potent and dose-dependent relaxant effects on the guinea pig fundic muscle. In addition, the results showed that resveratrol-induced relaxation of the guinea pig fundus occurs through nitric oxide and ATP-sensitive potassium channels. This study provides the first evidence concerning the relaxant effects of resveratrol in the guinea pig fundic muscle strips. Furthermore, resveratrol may be a potential drug to relieve gastrointestinal dyspepsia. Copyright © 2018 Elsevier GmbH. All rights reserved.

  16. Relaxation property of the fractional Brownian particle

    International Nuclear Information System (INIS)

    Wang Litan; Lung, C.W.

    1988-08-01

    Dynamic susceptibility of a diffusion system associated with the fractional Brownian motion (fBm) was examined for the fractal property of the Non-Debye relaxation process. The comparisons between fBm and other approaches were made. Anomalous diffusion and the Non-Debye relaxation processes were discussed with this approach. (author). 8 refs, 1 fig

  17. Lifshitz quasinormal modes and relaxation from holography

    NARCIS (Netherlands)

    Sybesma, Watse|info:eu-repo/dai/nl/369283074; Vandoren, Stefan|info:eu-repo/dai/nl/304830739

    2015-01-01

    We obtain relaxation times for field theories with Lifshitz scaling and with holographic duals Einstein-Maxwell-Dilaton gravity theories. This is done by computing quasinormal modes of a bulk scalar field in the presence of Lifshitz black branes. We determine the relation between relaxation time and

  18. Superparamagnetic relaxation of weakly interacting particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Tronc, Elisabeth

    1994-01-01

    The influence of particle interactions on the superparamagnetic relaxation time has been studied by Mossbauer spectroscopy in samples of maghemite (gamma-Fe2O3) particles with different particle sizes and particle separations. It is found that the relaxation time decreases with decreasing particl...

  19. Models of Flux Tubes from Constrained Relaxation

    Indian Academy of Sciences (India)

    tribpo

    J. Astrophys. Astr. (2000) 21, 299 302. Models of Flux Tubes from Constrained Relaxation. Α. Mangalam* & V. Krishan†, Indian Institute of Astrophysics, Koramangala,. Bangalore 560 034, India. *e mail: mangalam @ iiap. ernet. in. † e mail: vinod@iiap.ernet.in. Abstract. We study the relaxation of a compressible plasma to ...

  20. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies...

  1. Baryogenesis via Elementary Goldstone Higgs Relaxation

    DEFF Research Database (Denmark)

    Gertov, Helene; Pearce, Lauren; Sannino, Francesco

    2016-01-01

    We extend the relaxation mechanism to the Elementary Goldstone Higgs framework. Besides studying the allowed parameter space of the theory we add the minimal ingredients needed for the framework to be phenomenologically viable. The very nature of the extended Higgs sector allows to consider very ...... but radiatively generated, it is possible to generate the observed matter-antimatter asymmetry via the relaxation mechanism....

  2. Vibrational relaxation in liquids: Comparisons between gas phase and liquid phase theories

    International Nuclear Information System (INIS)

    Russell, D.J.

    1990-12-01

    The vibrational relaxation of iodine in liquid xenon was studied to understand what processes are important in determining the density dependence of the vibrational relaxation. This examination will be accomplished by taking simple models and comparing the results to both experimental outcomes and the predictions of molecular dynamics simulations. The vibration relaxation of iodine is extremely sensitive to the iodine potential. The anharmonicity of iodine causes vibrational relaxation to be much faster at the top of the iodine well compared to the vibrational relaxation at the bottom. A number of models are used in order to test the ability of the Isolated Binary Collision theory's ability to predict the density dependence of the vibrational relaxation of iodine in liquid xenon. The models tested vary from the simplest incorporating only the fact that the solvent occupies volume to models that incorporate the short range structure of the liquid in the radial distribution function. None of the models tested do a good job of predicting the actual relaxation rate for a given density. This may be due to a possible error in the choice of potentials to model the system

  3. Relaxation dynamics following transition of solvated electrons

    International Nuclear Information System (INIS)

    Barnett, R.B.; Landman, U.; Nitzan, A.

    1989-01-01

    Relaxation dynamics following an electronic transition of an excess solvated electron in clusters and in bulk water is studied using an adiabatic simulation method. In this method the solvent evolves classically and the electron is constrained to a specified state. The coupling between the solvent and the excess electron is evaluated via the quantum expectation value of the electron--water molecule interaction potential. The relaxation following excitation (or deexcitation) is characterized by two time scales: (i) a very fast (/similar to/20--30 fs) one associated with molecular rotations in the first solvation shell about the electron, and (ii) a slower stage (/similar to/200 fs), which is of the order of the longitudinal dielectric relaxation time. The fast relaxation stage exhibits an isotope effect. The spectroscopical consequences of the relaxation dynamics are discussed

  4. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

  5. Cross-relaxation solid state lasers

    International Nuclear Information System (INIS)

    Antipenko, B.M.

    1989-01-01

    Cross-relaxation functional diagrams provide a high quantum efficiency for pumping bands of solid state laser media and a low waste heat. A large number of the cross-relaxation mechanisms for decay rare earth excited states in crystals have been investigated. These investigations have been a starting-point for development of the cross-relaxation solid state lasers. For example, the cross-relaxation interactions, have been used for the laser action development of LiYF 4 :Gd-Tb. These interactions are important elements of the functional diagrams of the 2 μm Ho-doped media sensitized with Er and Tm and the 3 μm Er-doped media. Recently, new efficient 2 μm laser media with cross-relaxation pumping diagrams have been developed. Physical aspects of these media are the subject of this paper. A new concept of the Er-doped medium, sensitized with Yb, is illustrated

  6. NMR relaxation dispersion of Miglyol molecules confined inside polymeric micro-capsules.

    Science.gov (United States)

    Nechifor, Ruben; Ardelean, Ioan; Mattea, Carlos; Stapf, Siegfried; Bogdan, Mircea

    2011-11-01

    Frequency dependent NMR relaxation studies have been carried out on Miglyol molecules confined inside core shell polymeric capsules to obtain a correlation between capsule dimension and the measurable parameters. The polymeric capsules were prepared using an interfacial polymerization technique for three different concentrations of Miglyol. It was shown that the variation of Miglyol concentration influences the capsule dimension. Their average size was estimated using the pulsed field gradient diffusometry technique. The relaxation dispersion curves were obtained at room temperature by a combined use of a fast field cycling instrument and a high-field instrument. The frequency dependence of relaxation rate shows a transition from a diffusion-limited to a surface-limited relaxation regime. Copyright © 2011 John Wiley & Sons, Ltd.

  7. Relaxed and partially relaxed magnetic equilibria in tight-aspect-ratio tori

    International Nuclear Information System (INIS)

    Browning, P.K.; Clegg, J.R.; Duck, R.C.; Rusbridge, M.G.

    1993-01-01

    Force-free equilibrium magnetic fields in tight-aspect-ratio toroidal configurations are investigated. The study is mainly directed to modelling field configurations in the 'rodomak', a modification to the SPHEX gun-injected spheromak in which a current-carrying rod is inserted along the geometric axis. A family of analytical relaxed states (∇ x B = μB, μ constant) is presented for a torus of rectangular cross section, with boundary conditions allowing for flux embedded in the walls, representing the gun. Numerically calculated fields in SPHEX geometry, with μ profiles relevant to the driven phase of operation, are also given. The dependence of the field configurations and global quantities such as energy, helicity and toroidal current on the controlling parameters (gun flux, gun current and rod current) and geometry is discussed. (author)

  8. Effects of de-oiled palm kernel cake based fertilizers on sole maize ...

    African Journals Online (AJOL)

    AJL

    2012-03-08

    Mar 8, 2012 ... formulations on the yield of sole maize and cassava crops. Two de-oiled palm ..... establishment of nitrogen fixing bacteria in the rhizosphere. Microb ... Biological, and Social Sciences Research, 2nd Edition. Optimal Publ.

  9. AFSC/RACE/GAP/Nichol: Archival tag depth and temperature data from northern rock sole

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Depth data from archival tags on northern rock sole (Lepidopsetta polyxystra) were examined to assess whether fish used tidal currents to aid horizontal migration....

  10. Clinical application of platelet-rich fibrin as the sole grafting material in periodontal intrabony defects

    Directory of Open Access Journals (Sweden)

    Yu-Chao Chang

    2011-09-01

    Conclusions: From a clinical and radiologic point of view at 6 months after surgery, the use of PRF as the sole grafting material seems to be an effective modality of regenerative treatment for periodontal intrabony defects.

  11. 31 CFR 353.36 - Payment during life of sole owner.

    Science.gov (United States)

    2010-07-01

    ...) FISCAL SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE PUBLIC DEBT REGULATIONS GOVERNING DEFINITIVE... of sole owner. A savings bond registered in single ownership form (i.e., without a coowner or...

  12. 31 CFR 315.36 - Payment during life of sole owner.

    Science.gov (United States)

    2010-07-01

    ...) FISCAL SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE PUBLIC DEBT REGULATIONS GOVERNING U.S. SAVINGS... § 315.36 Payment during life of sole owner. A savings bond registered in single ownership form (i.e...

  13. Magnetic Resonance Fingerprinting with short relaxation intervals.

    Science.gov (United States)

    Amthor, Thomas; Doneva, Mariya; Koken, Peter; Sommer, Karsten; Meineke, Jakob; Börnert, Peter

    2017-09-01

    The aim of this study was to investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, in particular for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions. A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D. For accuracy analysis, T 1 and T 2 values of a phantom are determined by single-slice Cartesian MRF for different relaxation intervals and are compared with quantitative reference measurements. The relevance of slice profile effects is also investigated in this case. To further illustrate the capabilities of the method, an application to in-vivo spiral 3D MRF measurements is demonstrated. The proposed computation method enables accurate parameter estimation even for the shortest relaxation intervals, as investigated for different sampling patterns in 2D and 3D. In 2D Cartesian measurements, we achieved a scan acceleration of more than a factor of two, while maintaining acceptable accuracy: The largest T 1 values of a sample set deviated from their reference values by 0.3% (longest relaxation interval) and 2.4% (shortest relaxation interval). The largest T 2 values showed systematic deviations of up to 10% for all relaxation intervals, which is discussed. The influence of slice profile effects for multislice acquisition is shown to become increasingly relevant for short relaxation intervals. In 3D spiral measurements, a scan time reduction of 36% was achieved, maintaining the quality of in-vivo T1 and T2 maps. Reducing the relaxation interval between MRF sequence repetitions using stationary fingerprint dictionaries is a feasible method to improve the scan efficiency of MRF sequences. The method enables fast implementations of 3D spatially

  14. Corroborative evidences of TV γ -scaling of the α-relaxation originating from the primitive relaxation/JG β relaxation

    Science.gov (United States)

    Ngai, K. L.; Paluch, M.

    2017-12-01

    Successful thermodynamic scaling of the structural alpha-relaxation time or transport coefficients of glass-forming liquids determined at various temperatures T and pressures P means the data conform to a single function of the product variable TVgamma, where V is the specific volume and gamma is a material specific constant. In the past two decades we have witnessed successful TVgamma-scaling in many molecular, polymeric, and even metallic glass-formers, and gamma is related to the slope of the repulsive part of the intermolecular potential. The advances made indicate TVgamma-scaling is an important aspect of the dynamic and thermodynamic properties of glass-formers. In this paper we show the origin of TVgamma-scaling is not from the structural alpha-relaxation time. Instead it comes from its precursor, the Johari-Goldstein beta-relaxation or the primitive relaxation of the Coupling Model and their relaxation times or tau_0 respectively. It is remarkable that all relaxation times are functions of TVgamma with the same gama, as well as the fractional exponent of the Kohlrausch correlation function of the structural alpha-relaxation. We arrive at this conclusion convincingly based on corroborative evidences from a number of experiments and molecular dynamics simulations performed on a wide variety of glass-formers and in conjunction with consistency with the predictions of the Coupling Model.

  15. Amyotrophic Lateral Sclerosis Presenting Respiratory Failure as the Sole Initial Manifestation

    Directory of Open Access Journals (Sweden)

    Fuyuki Tateno

    2014-08-01

    Full Text Available It is rare that amyotrophic lateral sclerosis (ALS presents with respiratory failure as the sole initial manifestation. A 72-year-old man with mild chronic obstructive pulmonary disease developed exertional dyspnea for 13 months. He then progressed to limb weakness that led to the diagnosis of ALS. Although rare, ALS can present with respiratory failure as the sole initial manifestation more than 1 year prior to limb weakness.

  16. Structural evolution of the Semail Ophiolite metamorphic sole, Wadi Hawasina and Northern Jebel Nakhl Culmination, Oman

    Science.gov (United States)

    Hurtado, C.; Bailey, C.; Visokay, L.; Scharf, A.

    2017-12-01

    The Semail ophiolite is the world's largest and best-exposed ophiolite sequence, however the processes associated with both oceanic detachment and later emplacement onto the Arabian continental margin remain enigmatic. This study examines the upper mantle section of the ophiolite, its associated metamorphic sole, and the autochthonous strata beneath the ophiolite at two locations in northern Oman. Our purpose is to understand the structural history of ophiolite emplacement and evaluate the deformation kinematics of faulted and sheared rocks in the metamorphic sole. At Wadi Hawasina, the base of the ophiolite is defined by a 5- to 15-m thick zone of penetratively-serpentinized mylonitic peridotite. Kinematic indicators record top-to-the SW (reverse) sense-of-shear with a triclinic deformation asymmetry. An inverted metamorphic grade is preserved in the 300- to 500-m thick metamorphic sole that is thrust over deep-water sedimentary rocks of the Hawasina Group. The study site near Buwah, in the northern Jebel Nakhl culmination, contains a N-to-S progression of mantle peridotite, metamorphic sole, and underlying Jurassic carbonates. Liswanite crops out in NW-SE trending linear ridges in the peridotite. The metamorphic sole includes well-foliated quartzite, metachert, and amphibolite. Kinematic evidence indicates that the liswanite and a serpentinized mélange experienced top to-the north (normal) sense-of-shear. Two generations of E-W striking, N-dipping normal faults separate the autochthonous sequence from the metamorphic sole, and also cut out significant sections of the metamorphic sole. Fabric analysis reveals that the metamorphic sole experienced flattening strain (K<0.2) that accumulated during pure shear-dominated general shear (Wk<0.4). Normal faulting and extension at the Buwah site indicates that post-ophiolite deformation is significant in the Jebel Akhdar and Jebel Nakhl culminations.

  17. Simulating the Behavioural Effects of Welfare Reforms among Sole Parents in Australia

    OpenAIRE

    Alan Duncan; Mark N. Harris

    2001-01-01

    This paper derives and estimates an econometric model of labour supply among sole parents in Australia, using modelling techniques which treat the labour supply decision as a utility maximising choice between a given number of discrete states. In estimation, we control for random preference heterogeneity as well as Þxed and search costs. Using our econometric model, we look at the e.ects of actual and hypothetical welfare policy reforms on the employment choices of sole parents in Australia. ...

  18. Relaxing a large cosmological constant

    International Nuclear Information System (INIS)

    Bauer, Florian; Sola, Joan; Stefancic, Hrvoje

    2009-01-01

    The cosmological constant (CC) problem is the biggest enigma of theoretical physics ever. In recent times, it has been rephrased as the dark energy (DE) problem in order to encompass a wider spectrum of possibilities. It is, in any case, a polyhedric puzzle with many faces, including the cosmic coincidence problem, i.e. why the density of matter ρ m is presently so close to the CC density ρ Λ . However, the oldest, toughest and most intriguing face of this polyhedron is the big CC problem, namely why the measured value of ρ Λ at present is so small as compared to any typical density scale existing in high energy physics, especially taking into account the many phase transitions that our Universe has undergone since the early times, including inflation. In this Letter, we propose to extend the field equations of General Relativity by including a class of invariant terms that automatically relax the value of the CC irrespective of the initial size of the vacuum energy in the early epochs. We show that, at late times, the Universe enters an eternal de Sitter stage mimicking a tiny positive cosmological constant. Thus, these models could be able to solve the big CC problem without fine-tuning and have also a bearing on the cosmic coincidence problem. Remarkably, they mimic the ΛCDM model to a large extent, but they still leave some characteristic imprints that should be testable in the next generation of experiments.

  19. Stress relaxation in SSC 50mm dipole coils

    International Nuclear Information System (INIS)

    Rogers, D.; Markley, F.

    1992-04-01

    We are measuring the stress relaxation of SSC 50mm outer coils with the goal of predicting how much of the coil prestress will be lost while the coils are warehoused between manufacture and cooldown. We manufacture 3 inch (76.2mm) long segments of coil with the same materials and techniques that have been used for prototype coils. We are running four simultaneous tests in an attempt to separate the contributions of the different coil materials. Test one is a completely insulated coil section where the insulation is the all polyamide system being tested at Brookhaven; test two is a wire stack insulated only with the normal Kapton overwrap; test three is a stack of bare cable; and test four is a completely insulated normal coil section. All, except for the bare cable, include the ground insulation. The insulated coil sections are carefully dried before loading and testing in order to eliminate stress changes due to varying moisture content. The temperature dependence of the stress relaxation is being studied separately. Three companion papers presented at this conference will be: (1) ''Temperature dependence of the viscoelastic properties of SSC coil insulation'' (2) ''Measurement of the elastic modulus of Kapton perpendicular to the plane of the film at room and cryogenic temperatures'' (3) ''Theoretical methods for creep and stress relaxation studies of SSC coil.''

  20. Multiplied effect of heat and radiation in chemical stress relaxation

    International Nuclear Information System (INIS)

    Ito, Masayuki

    1981-01-01

    About the deterioration of rubber due to radiation, useful knowledge can be obtained by the measurement of chemical stress relaxation. As an example, the rubber coating of cables in a reactor containment vessel is estimated to be irradiated by weak radiation at the temperature between 60 and 90 deg C for about 40 years. In such case, it is desirable to establish the method of accelerated test of the deterioration. The author showed previously that the law of time-dose rate conversion holds in the case of radiation. In this study, the chemical stress relaxation to rubber was measured by the simultaneous application of heat and radiation, and it was found that there was the multiplied effect of heat and radiation in the stress relaxation speed. Therefore the factor of multiplication of heat and radiation was proposed to describe quantitatively the degree of the multiplied effect. The chloroprene rubber used was offered by Hitachi Cable Co., Ltd. The experimental method and the results are reported. The multiplication of heat and radiation is not caused by the direct cut of molecular chains by radiation, instead, it is based on the temperature dependence of various reaction rates at which the activated species reached the cut of molecular chains through complex reaction mechanism and the temperature dependence of the diffusion rate of oxygen in rubber. (Kako, I.)

  1. The effects of progressive muscle relaxation and autogenic relaxation on young soccer players' mood states.

    Science.gov (United States)

    Hashim, Hairul Anuar; Hanafi Ahmad Yusof, Hazwani

    2011-06-01

    This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players' mood states.

  2. The Effects of Progressive Muscle Relaxation and Autogenic Relaxation on Young Soccer Players’ Mood States

    Science.gov (United States)

    Hashim, Hairul Anuar; Hanafi@Ahmad Yusof, Hazwani

    2011-01-01

    Purpose This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. Methods Sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Results Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. Conclusion These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players’ mood states. PMID:22375225

  3. CONTRIBUTIONS TO DIVERSIFY SOLES MOULDS THAT FORMS DIRECTLY ON FACES SHOES

    Directory of Open Access Journals (Sweden)

    IONESCU Cozmin

    2015-05-01

    Full Text Available The classical moulds which are currently used for forming the soles directly on the uppers, allow obtaining one sole model. One mould for each foot is made, and at least one mould for each size number in the size number series. To manufacture one single sole model in the sizes series an average set of 16 moulds are needed. Changing the model implies the entire production of a new set of moulds. Therefore, a large diversification of the soles requires the manufacturing a quantity of moulds sets equal with the quantity of sole models. In this paper are presented solutions to obtain more cavity shapes in the same mould, through the use of modular interchangeable pieces. The moulds with versatile cavities have the same functional characteristics as the moulds with unique cavities, are usable on the same type of machines and can be used independently or together with the classical moulds. A brief analysis on the technological processes for manufacturing moulds with versatile cavities reveals a significant lowering of the manufacturing time for moulds in which will be obtained other sole models. This is due to the fact that some of the mould parts are reused. In conclusion, the producers that chose this type of moulds can launch on the market new models in a shorter time and at lower prices.

  4. Vibrational relaxation of matrix-isolated CH3F and HCl

    International Nuclear Information System (INIS)

    Young, L.

    1981-08-01

    Kinetic and spectroscopic studies have been performed on CH 3 F and HCl as a function of host matrix and temperature. Temporally and spectrally resolved infrared fluorescence was used to monitor the populations of both the initially excited state and the lower lying levels which participate in the relaxation process. For CH 3 F, relaxation from any of the levels near 3.5 μ, i.e. the CH stretching fundamentals or bend overtones, occurs via rapid ( 3 with subsequent relaxation of the ν 3 (CF stretch) manifold. Lifetimes of 2ν 3 and ν 3 were determined through overtone, ΔV = 2, and fundamental fluorescence. These lifetimes show a dramatic dependence on host lattice, an increase of two orders of magnitude in going from Xe and Ar matrices. Lifetimes depend only weakly on temperature. The relaxation of 2ν 3 and ν 3 is consistent with a model in which production of a highly rotationally excited guest via collisions with the repulsive wall of the host is the rate limiting step. For HCl, lifetimes of v = 1,2,3 have been determined. In all hosts, the relaxation is non-radiative. For a given vibrational state, v, the relaxation rate increases in the series k(Ar) < k(Kr) < k(Xe). The dependence of the relaxation rate; on v is superlinear in all matrices, the deviation from linearity increasng in the order Ar < Kr < Xe. The relaxation rates become more strongly temperature dependent with increasing vibrational excitation. The results are consistent with a mechanism in which complex formation introduces the anisotropy necessary to induce a near resonant V → R transition in the rate limiting step

  5. Photoconductivity relaxation and electron transport in macroporous silicon structures

    Directory of Open Access Journals (Sweden)

    L.A. Karachevtseva

    2017-12-01

    Full Text Available Kinetics and temperature dependence of photoconductivity were measured in macroporous silicon at 80…300 K after light illumination with the wavelength 0.9 μm. The influence of mechanisms of the charge carrier transport through the macropore surface barrier on the kinetics of photoconductivity at various temperatures was investigated. The kinetics of photoconductivity distribution in macroporous silicon and Si substrate has been calculated using the finite-difference time-domain method. The maximum of photoconductivity has been found both in the layer of macroporous silicon and in the monocrystalline substrate. The kinetics of photoconductivity distribution in macroporous silicon showed rapid relaxation of the photoconductivity maximum in the layer of macroporous silicon and slow relaxation of it in the monocrystalline substrate.

  6. On relaxation mechanism of tangensial losses in soils

    International Nuclear Information System (INIS)

    Babayev, M.P.; Gerayzade, A.P.; Mamedov, N.A.

    2009-01-01

    By experimentally at high-frequency bridge method on dependence of a tangent of a corner of dielectric losses of soil fom humidity and frequency of an electromagnetic field are investigated. In air-dry samples of soils the size of the most probable time of a relaxation and its maximum is established. It is shown that in the field of gravitational humidity, in the soil sample, at a maximum of a tangent of a corner of dielectric losses through conductivity will be veiled, i.e. obviously is not shown. As a result of the received data it is established that in the field of the adsorbed soil moisture the spectrum of time of relaxation is characterized by the wide strip reflecting heterogeneity of its dielectric properties. All this is offered to be used at designing of delkometric hydrometers and measurement of soil humidity

  7. Donor-driven spin relaxation in multivalley semiconductors.

    Science.gov (United States)

    Song, Yang; Chalaev, Oleg; Dery, Hanan

    2014-10-17

    The observed dependence of spin relaxation on the identity of the donor atom in n-type silicon has remained without explanation for decades and poses a long-standing open question with important consequences for modern spintronics. Taking into account the multivalley nature of the conduction band in silicon and germanium, we show that the spin-flip amplitude is dominated by short-range scattering off the central-cell potential of impurities after which the electron is transferred to a valley on a different axis in k space. Through symmetry arguments, we show that this spin-flip process can strongly affect the spin relaxation in all multivalley materials in which time-reversal cannot connect distinct valleys. From the physical insights gained from the theory, we provide guidelines to significantly enhance the spin lifetime in semiconductor spintronics devices.

  8. Relaxation of stresses during reduction of anode supported SOFCs

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Jørgensen, Peter Stanley

    2016-01-01

    To assess the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of a Ni-YSZ anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. Thus, the phenomenon of accelerated creep during reduction has to be considered both in the production of stacks and in the analysis of the stress field...... of reduction should decrease significantly over minutes. In this work these internal stresses are measured in-situ before and after the reduction by use of X-ray diffraction. This is done by determining the elastic micro-strains (correlating to the stresses), which are assessed from the widening of the Bragg...

  9. Segmental dynamics in polymer melts by relaxation techniques and quasielastic neutron scattering

    Science.gov (United States)

    Colmenero, J.

    1993-01-01

    The dynamics of the segmental α-relaxation in three different polymeric systems, poly(vinyl methy ether) (PVME), poly(vinyl chloride) (PVC) and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of relaxation techniques and quasielastic neutron scattering (backscattering spectrometers IN10 and IN13 at the ILL-Grenoble). By using these techniques we have covered a wide timescale ranging from mesoscopic to macroscopic times (10-10-101s). For analyzing the experimental data we have developed a phenomenological procedure in the frequency domain based on the Havriliak-Negami relaxation function which in fact implies a Kohlrausch-Williams-Watts relaxation function in the time domain. The results obtained indicate that the dynamics of the α-relaxation in a wide timescale shows a clear non-Debye behaviour. The shape of the relaxation function is found to be similar for the different techniques used and independent of temperature and momentum transfer (Q). Moreover the characteristic relaxation times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. Besides we found that the Q-dependence of the relaxation times obtained by QENS is given by a power law, τ(Q) propto Q-n (n > 2) n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. We discuss this correlation taking into account several data of the dynamics of the α-relaxation previously reported in the literature. We also outline a possible scenario for explaining this empirical correlation.

  10. β-adrenergic relaxation of smooth muscle: differences between cells and tissues

    International Nuclear Information System (INIS)

    Scheid, C.R.

    1987-01-01

    The present studies were carried out in an attempt to resolve the controversy about the Na + dependence of β-adrenergic relaxation in smooth muscle. Previous studies on isolated smooth muscle cells from the toad stomach had suggested that at least some of the actions of β-adrenergic agents, including a stimulatory effect on 45 Ca efflux, were dependent on the presence of a normal transmembrane Na + gradient. Studies by other investigators using tissues derived from mammalian sources had suggested that the relaxing effect of β-adrenergic agents was Na + independent. Uncertainty remained as to whether these discrepancies reflected differences between cells and tissues or differences between species. Thus, in the present studies, the authors utilized both tissues and cells from the same source, the stomach muscle of the toad Bufo marinus, and assessed the Na + dependence of β-adrenergic relaxation. They found that elimination of a normal Na + gradient abolished β-adrenergic relaxation of isolated cells. In tissues, however, similar manipulations had no effect on relaxation. The reasons for this discrepancy are unclear but do not appear to be attributable to changes in smooth muscle function following enzymatic dispersion. Thus the controversy concerning the mechanisms of β-adrenergic relaxation may reflect inherent differences between tissues and cells

  11. Volume and structural relaxation in compressed sodium borate glass.

    Science.gov (United States)

    Svenson, Mouritz N; Youngman, Randall E; Yue, Yuanzheng; Rzoska, Sylwester J; Bockowski, Michal; Jensen, Lars R; Smedskjaer, Morten M

    2016-11-21

    The structure and properties of glass can be modified through compression near the glass transition temperature (T g ), and such modified structure and properties can be maintained at ambient temperature and pressure. However, once the compressed glass undergoes annealing near T g at ambient pressure, the modified structure and properties will relax. The challenging question is how the property relaxation is correlated with both the local and the medium-range structural relaxation. In this paper, we answer this question by studying the volume (density) and structural relaxation of a sodium borate glass that has first been pressure-quenched from its T g at 1 GPa, and then annealed at ambient pressure under different temperature-time conditions. Using 11 B MAS NMR and Raman spectroscopy, we find that the pressure-induced densification of the glass is accompanied by a conversion of six-membered rings into non-ring trigonal boron (B III ) units, i.e. a structural change in medium-range order, and an increase in the fraction of tetrahedral boron (B IV ), i.e. a structural change in short-range order. These pressure-induced structural conversions are reversible during ambient pressure annealing near T g , but exhibit a dependence on the annealing temperature, e.g. the ring/non-ring B III ratio stabilizes at different values depending on the applied annealing temperature. We find that conversions between structural units cannot account for the pressure-induced densification, and instead we suggest the packing of structural units as the main densification mechanism.

  12. Radiation capture and use as affected by morphologicallycontrasting maize/pea in sole and intercropping

    International Nuclear Information System (INIS)

    Kanton, R.A.L.; Dennett, M.D.

    2008-01-01

    Field experiments were conducted at the Field Unit of the School of Plant Sciences in Reading, UK, during the 2000 and 2001 growing seasons to compare the radiation capture and use efficiency of morphologically and physiologically contrasting maize/pea intercrops with sole crops. The maize cultivars comprised Nancis with erect and Sophy with floppy leaves whilst the peas consisted of Maro, a conventional leaved, and Princess, a semi-leafless cultivar. Radiation capture by the sole and intercrops was measured using a Sunflek Ceptometer (Delta T Devices), with a sensor length of 80 cm. Measurements were taken at four equidistant positions in each plot, 1 m away from the edges of the plot. Before the maize grew above the peas, measurements were taken at the top of the canopy and below. When the canopies were distinct, three measurements were taken, above the canopy, above peas and below the canopy from 9.30 a.m. to 1.00 p.m. at weekly intervals. In both seasons the intercrops and sole pea crops intercepted more radiation compared to the sole maize crops. Towards the end of the season the intercrops and sole maize had similar interception. Intercropping both maize cultivars in 2000 with the conventional pea had the greatest interception in 2001. Radiation use efficiency (RUE) was measured by taking the respective changes in above ground dry weight and dividing by the respective changes in cumulative absorbed photosynthetic active radiation (PAR). The RUE were highest at mid-season for both intercrops and sole crops in both seasons. Comparisons were also made using cumulative radiation use efficiencies (CRUE), representing the RUE from emergence to any time. Sole pea had the lowest RUE in both seasons. The sole maize in 2000 had highest CRUE. However, in 2001 intercrops had similar RUE to sole maize, suggesting an increase in RUE of peas in intercrops. Nancis had consistently higher RUE in both seasons compared to Sophy. The results emphasize that radiation capture and

  13. Radiation capture and use as affected by morphologically contrasting maize/pea in sole and intercropping

    International Nuclear Information System (INIS)

    Kanton, R. A. L.; Dennett, M. D.

    2008-01-01

    Field experiments were conducted at the Field Unit of the School of Plant Sciences in Reading, UK, during the 2000 and 2001 growing seasons to compare the radiation capture and use efficiency of morphologically and physiologically contrasting maize/pea intercrops with sole crops. The maize cultivars comprised Nancis with erect and Sophy with floppy leaves whilst the peas consisted of Maro, a conventional leaved, and Princess, a semi-leafless cultivar. Radiation capture by the sole and intercrops was measured using a Sunflek Ceptometer (Delta T Devices), with a sensor length of 80 cm. Measurements were taken at four equidistant positions in each plot, 1 m away from the edges of the plot. Before the maize grew above the peas, measurements were taken at the top of the canopy and below. When the canopies were distinct, three measurements were taken, above the canopy, above peas and below the canopy from 9.30 a.m. to 1.00 p.m. at weekly intervals. In both seasons the intercrops and sole pea crops intercepted more radiation compared to the sole maize crops. Towards the end of the season the intercrops and sole maize had similar interception. Intercropping both maize cultivars in 2000 with the conventional pea had the greatest interception in 2001. Radiation use efficiency (RUE) was measured by taking the respective changes in above ground dry weight and dividing by the respective changes in cumulative absorbed photosynthetic active radiation (PAR). The RUE were highest at mid-season for both intercrops and sole crops in both seasons. Comparisons were also made using cumulative radiation use efficiencies (CRUE), representing the RUE from emergence to any time. Sole pea had the lowest CRUE in both seasons. The sole maize in 2000 had highest CRUE. However, in 2001 intercrops had similar CRUE to sole maize, suggesting an increase in RUE of peas in intercrops. Nancis had consistently higher CRUE in both seasons compared to Sophy. The results emphasize that radiation capture

  14. Dielectric relaxation study of the dynamics of monosaccharides: D-ribose and 2-deoxy-D-ribose

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, K; Kaminska, E; Wlodarczyk, P; Paluch, M; Ziolo, J [Institute of Physics, Silesian University, ulica Uniwersytecka 4, 40-007 Katowice (Poland); Ngai, K L [Naval Research Laboratory, Washington, DC 20375-5320 (United States)

    2008-08-20

    The dielectric loss spectra of two closely related monosaccharides, D-ribose and 2-deoxy-D-ribose, measured at ambient and elevated pressures are presented. 2-deoxy-D-ribose and D-ribose are respectively the building blocks of the backbone chains in the nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Small differences in the structure between D-ribose and 2-deoxy-D-ribose result in changes of the glass transition temperature T{sub g}, as well as the dielectric strength and activation enthalpy of the secondary relaxations. However, the frequency dispersion of the structural {alpha}-relaxation for the same relaxation time remains practically the same. Two secondary relaxations are present in both sugars. The slower secondary relaxation shifts to lower frequencies with increasing applied pressure, but not the faster one. This pressure dependence indicates that the slower secondary relaxation is the important and 'universal' Johari-Goldstein {beta}-relaxation of both sugars according to one of the criteria set up to classify secondary relaxations. Additional confirmation of this conclusion comes from good agreement of the observed relaxation time of the slower secondary relaxation with the primitive relaxation time calculated from the coupling model. All the dynamic properties of D-ribose and 2-deoxy-D-ribose are similar to the other monosaccharides, glucose, fructose, galactose and sorbose, except for the much larger relaxation strength of the {alpha}-relaxation of the former compared to the latter. The difference may distinguish the chemical and biological functions of D-ribose and 2-deoxy-D-ribose from the other monosaccharides.

  15. Relaxation of polarized nuclei in superconducting rhodium

    DEFF Research Database (Denmark)

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

    2000-01-01

    Nuclear spin lattice relaxation rates were measured in normal and superconducting (sc) rhodium with nuclear polarizations up to p = 0.55. This was sufficient to influence the sc state of Rh, whose T, and B-c, are exceptionally low. Because B-c ... is unchanged, the nuclear spin entropy was fully sustained across the sc transition. The relaxation in the sc state was slower at all temperatures without the coherence enhancement close to T-c. Nonzero nuclear polarization strongly reduced the difference between the relaxation rates in the sc and normal...

  16. Spin relaxation in nanowires by hyperfine coupling

    International Nuclear Information System (INIS)

    Echeverria-Arrondo, C.; Sherman, E.Ya.

    2012-01-01

    Hyperfine interactions establish limits on spin dynamics and relaxation rates in ensembles of semiconductor quantum dots. It is the confinement of electrons which determines nonzero hyperfine coupling and leads to the spin relaxation. As a result, in nanowires one would expect the vanishing of this effect due to extended electron states. However, even for relatively clean wires, disorder plays a crucial role and makes electron localization sufficient to cause spin relaxation on the time scale of the order of 10 ns. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Le Chatelier's principle with multiple relaxation channels

    Science.gov (United States)

    Gilmore, R.; Levine, R. D.

    1986-05-01

    Le Chatelier's principle is discussed within the constrained variational approach to thermodynamics. The formulation is general enough to encompass systems not in thermal (or chemical) equilibrium. Particular attention is given to systems with multiple constraints which can be relaxed. The moderation of the initial perturbation increases as additional constraints are removed. This result is studied in particular when the (coupled) relaxation channels have widely different time scales. A series of inequalities is derived which describes the successive moderation as each successive relaxation channel opens up. These inequalities are interpreted within the metric-geometry representation of thermodynamics.

  18. Universal Mechanism of Spin Relaxation in Solids

    Science.gov (United States)

    Chudnovsky, Eugene

    2006-03-01

    Conventional elastic theory ignores internal local twists and torques. Meantime, spin-lattice relaxation is inherently coupled with local elastic twists through conservation of the total angular momentum (spin + lattice). This coupling gives universal lower bound (free of fitting parameters) on the relaxation of the atomic or molecular spin in a solid [1] and on the relaxation of the electron spin in a quantum dot [2]. [1] E. M. Chudnovsky, D. A. Garanin, and R. Schilling, Phys. Rev. B 72, 094426 (2005). [2] C. Calero, E. M. Chudnovsky, and D. A. Garanin, Phys. Rev. Lett. 95, 166603 (2005).

  19. Nuclear magnetic resonance relaxation in multiple sclerosis

    DEFF Research Database (Denmark)

    Larsson, H B; Barker, G J; MacKay, A

    1998-01-01

    OBJECTIVES: The theory of relaxation processes and their measurements are described. An overview is presented of the literature on relaxation time measurements in the normal and the developing brain, in experimental diseases in animals, and in patients with multiple sclerosis. RESULTS...... AND CONCLUSION: Relaxation time measurements provide insight into development of multiple sclerosis plaques, especially the occurrence of oedema, demyelination, and gliosis. There is also evidence that normal appearing white matter in patients with multiple sclerosis is affected. What is now needed are fast...

  20. Stress Relaxation in Entangled Polymer Melts

    DEFF Research Database (Denmark)

    Hou, Ji-Xuan; Svaneborg, Carsten; Everaers, Ralf

    2010-01-01

    We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements...... and into the terminal relaxation regime for Z=10. Using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems, we have performed parameter-free tests of several different tube models. We find...

  1. Slow relaxation in weakly open rational polygons.

    Science.gov (United States)

    Kokshenev, Valery B; Vicentini, Eduardo

    2003-07-01

    The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.

  2. [A study on Korean concepts of relaxation].

    Science.gov (United States)

    Park, J S

    1992-01-01

    Relaxation technique is an independent nursing intervention used in various stressful situations. The concept of relaxation must be explored for the meaning given by the people in their traditional thought and philosophy. Korean relaxation technique, wanting to become culturally acceptable and effective, is learning to recognize and develop Korean concepts, experiences, and musics of relaxation. This study was aimed at discovering Korean concepts, experiences and musics of relaxation and contributing the development of the relaxation technique for Korean people. The subjects were 59 nursing students, 39 hospitalized patients, 61 housewives, 21 rural residents and 16 researchers. Data were collected from September 4th to October 24th, 1991 by interviews or questionnaires. The data analysis was done by qualitative research method, and validity assured by conformation of the concept and category by 2 nursing scientists who had written a Master's thesis on the relaxation technique. The results of the study were summarized as follows; 1. The meaning of the relaxation concept; From 298 statements, 107 concepts were extracted and then 5 categories "Physical domain", "Psychological domain", "Complex domain", "Situation", and "environment" were organized. 'Don't have discomforts, 'don't have muscle tension', 'don't have energy (him in Korean)', 'don't have activities' subcategories were included in "Physical domain". 'Don't have anxiety', 'feel good', 'emotional stability', 'don't have wordly thoughts', 'feel one's brain muddled', 'loss of desire' subcategories were included in "physical domain" 'Comfort body and mind', 'don't have tension of body and mind', 'be sagged' 'liveliness of thoughts' subcategories were included in "Complex domain". 'Rest', 'sleep', 'others' subcategories were included in "Situation domain". And 'quite environment' & 'comfortable environment' subcategories were included in "Environmental domain". 2. The experiences of the relaxation; From 151

  3. H-index is important for postural control for people with impaired foot sole sensation.

    Directory of Open Access Journals (Sweden)

    Shuqi Zhang

    Full Text Available People with Peripheral Neuropathy (PN, especially those with impaired sensory inputs through the small-afferent fiber (type II afferent fibers reflex loop (SAF, might depend more on the large-afferent fiber (type I afferent fibers reflex loop (LAF for postural control.To examine whether the function of the LAF reflex loop, reflected by the H-reflex and ankle joint proprioception, influences postural control when the SAF reflex loop is impaired, as indicated by reduced foot sole cutaneous sensation.Thirteen participants (8 women, 5 men diagnosed with PN and 12 age-matched controls (7 women, 5 men completed the testing protocol. Measures of interest included the H-index, active (AAP and passive (PAP ankle proprioception, plantar pressure sensitivity (PPS, average sway velocity (VAVG and area (A95 during 30 seconds eyes-closed standing, 6-minute walk distance (6MWD and timed up-and-go duration (TUG.Statistically significant group-dependent regression was observed between VAVG and H-index. Compared to the control group, the PN group demonstrated reduced PPS (2.0 ± 1.9 vs. 4.2 ± 1.2, P < .05 and H-index (63.6 ± 10.9 vs. 76.4 ± 16.0, P < .05, greater VAVG (3.5 ± 2.1 vs. 1.6 ± 0.6 cm/s, P < .05 and A95 (10.0 ± 10.1 vs. 2.5 ± 1.5 cm2, P < .05, shorter 6MWD (442.2 ± 93.0 vs. 525.3 ± 68.2 m, P < .05, and longer TUG (9.4 ± 1.6 vs. 6.5 ± 1.3 s, P < .05. Within the PN group, but not the control group, the H-index was correlated with VAVG (r = -.56, P < .05. Moreover, within the PN group only, PAP scores were correlated with 6MWD (r = -.68, P < .05 and TUG (r = -.59, P < .05 performance. No other statistically significant group difference, correlation or group-dependent regression was observed.VAVG, 6MWD, and TUG correlated with LAF reflex loop function observed among those with impaired functioning of the SAF reflex loop. This observation suggests that the LAF reflex loop may be critical to the control of balance in those individuals suffering

  4. Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels

    International Nuclear Information System (INIS)

    Roberts, R.E.; Allen, S.; Chang, A.P.Y.; Henderson, H.; Hobson, G.C.; Karania, B.; Morgan, K.N.; Pek, A.S.Y.; Raghvani, K.; Shee, C.Y.; Shikotra, J.; Street, E.; Abbas, Z.; Ellis, K.; Heer, J.K.; Alexander, S.P.H.

    2013-01-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (−)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (−)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  5. Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, R.E., E-mail: Richard.roberts@nottingham.ac.uk; Allen, S.; Chang, A.P.Y.; Henderson, H.; Hobson, G.C.; Karania, B.; Morgan, K.N.; Pek, A.S.Y.; Raghvani, K.; Shee, C.Y.; Shikotra, J.; Street, E.; Abbas, Z.; Ellis, K.; Heer, J.K.; Alexander, S.P.H., E-mail: steve.alexander@nottingham.ac.uk

    2013-11-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (−)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (−)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  6. Impairment of the vascular relaxation and differential expression of caveolin-1 of the aorta of diabetic +db/+db mice.

    Science.gov (United States)

    Lam, Tze Yan; Seto, Sai Wang; Lau, Yee Man; Au, Lai Shan; Kwan, Yiu Wa; Ngai, Sai Ming; Tsui, Kwong Wing

    2006-09-28

    In this study, we compared the endothelium-dependent and -independent relaxation of the isolated thoracic aorta of control (+db/+m) and diabetic (+db/+db) (C57BL/KsJ) mice. The gene expression (mRNA and protein) level of the muscarinic M(3) receptors, endothelial nitric oxide synthase (eNOS) and caveolin-1 of the aorta was also evaluated. Acetylcholine caused a concentration-dependent, N(G)-nitro-L-arginine methyl-ester (20 microM)-sensitive relaxation, with approximately 100% relaxation at 10 microM, in +db/+m mice. In +db/+db mice, the acetylcholine-induced relaxation was significantly smaller (maximum relaxation: approximately 80%). The sodium nitroprusside-mediated relaxation was slightly diminished in +db/+db mice, compared to +db/+m mice. However, there was no significant difference in the isoprenaline- and cromakalim-induced relaxation observed in both species. The mRNA and protein expression levels of caveolin-1 were significantly higher in the aorta of +db/+db mice. In contrast, there was no difference in the mRNA and protein expression levels of eNOS and muscarinic M(3) receptors between these mice. Our results demonstrate that the impairment of the acetylcholine-induced, endothelium-dependent aortic relaxation observed in +db/+db mice was probably associated with an enhanced expression of caveolin-1 mRNA and protein.

  7. A nuclear magnetic relaxation study on internal motion of polyelectrolytes in solution

    International Nuclear Information System (INIS)

    Schriever, J.

    1977-01-01

    The aim of this thesis is to investigate the significance and the amount of information which can be extracted from the study of frequency dependence of magnetic relaxation rates in solutions of a synthetic macromolecule. Solutions of poly(methacrylic acid), PMA, in water were chosen as the object of the present work. A short survey of nuclear magnetic relaxation in solutions of simple macromolecules is presented. Results obtained by continuous wave experiments on PMA solutions are shown (viz. the information about the transverse relaxation from line width analysis of 60 MHz proton spectra). Water enriched in 17 O is used in magnetic relaxation studies; the results of the determination of hydrogen lifetimes in aqueous solutions of acetic acid and poly(methacrylic acid) are given. The possibility of obtaining information about the dynamics of deuterons in the acid side groups of weak polyacids by measuring deuteron relaxation in heavy water solutions of those acids is considered. The use of deuteron relaxation rate experiments on solutions of selectively methylene deuterated poly(methacrylic acid), [-CD 2 -CCH 3 COOH-]n, is demonstrated and the backbone methylene C-atom motion is charachterized. The magne-tic relaxation of nuclei in the side groups of methylene deuterated PMA, viz. protons in the methyland deuterons in the acid side groups is presented

  8. Generalized extended Navier-Stokes theory: multiscale spin relaxation in molecular fluids.

    Science.gov (United States)

    Hansen, J S

    2013-09-01

    This paper studies the relaxation of the molecular spin angular velocity in the framework of generalized extended Navier-Stokes theory. Using molecular dynamics simulations, it is shown that for uncharged diatomic molecules the relaxation time decreases with increasing molecular moment of inertia per unit mass. In the regime of large moment of inertia the fast relaxation is wave-vector independent and dominated by the coupling between spin and the fluid streaming velocity, whereas for small inertia the relaxation is slow and spin diffusion plays a significant role. The fast wave-vector-independent relaxation is also observed for highly packed systems. The transverse and longitudinal spin modes have, to a good approximation, identical relaxation, indicating that the longitudinal and transverse spin viscosities have same value. The relaxation is also shown to be isomorphic invariant. Finally, the effect of the coupling in the zero frequency and wave-vector limit is quantified by a characteristic length scale; if the system dimension is comparable to this length the coupling must be included into the fluid dynamical description. It is found that the length scale is independent of moment of inertia but dependent on the state point.

  9. Relaxation process of coherent transients in the presence of an adjacent strongly driven transition

    International Nuclear Information System (INIS)

    Feng Xiaomin; Yang Lijun; Li Xiaoli; Zhang Lianshui; Han Li; Guo Qinglin; Fu Guangsheng

    2007-01-01

    Coherent transient occurs when a two-level transition is subjected to pulsed laser excitation. The relaxation process of coherent transient depends on both the longitudinal and transverse relaxation parameters of the two-level transition, which is related to the population and coherence decay rates. In this paper we study relaxation process of a new type coherent transients observed by applying a pulsed laser excitation to a two-level transition in the presence of a second strong continuous-wave (cw) coherent field coupling one of the two levels to a third level, that is, in a three-level double-resonance configuration. The relaxation process of coherent transients is studied as a function of relaxation parameters of both the two-level transition excited by the pulsed laser field and the transition coupled by the cw laser field. It is shown that by involving a third level with coherent field the relaxation process of coherent transients of a two-level transition can be modified. Our study illustrates a new way of controlling relaxation process of coherent transients in a two-level transition by a second coherent laser and this has important implication for quantum information storage and quantum computing

  10. Experimental and model-based analysis of differences in perception of cutaneous electrical stimulation across the sole of the foot.

    Science.gov (United States)

    Frahm, Ken Steffen; Mørch, Carsten Dahl; Grill, Warren M; Andersen, Ole Kæseler

    2013-09-01

    During electrocutaneous stimulations, variation in skin properties across locations can lead to differences in neural activation. However, little focus has been given to the effect of different skin thicknesses on neural activation. Electrical stimulation was applied to six sites across the sole of the foot. The intensities used were two and four times perception threshold. The subjects (n = 8) rated the perception quality and intensity using the McGill Pain Questionnaire and a visual analog scale (VAS). A finite element model was developed and combined with the activation function (AF) to estimate neural activation. Electrical stimulation was perceived as significantly less sharp at the heel compared to all other sites, except one site in the forefoot (logistic regression, p model showed that the AF was between 91 and 231 % higher at the five other sites than at the heel. The differences in perception across the sole of the foot indicated that the CNS received different inputs depending on the stimulus site. The lower AF at the heel indicated that the skin thicknesses could contribute to the perceived differences.

  11. 75 FR 51185 - Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Rock Sole in the Bering Sea...

    Science.gov (United States)

    2010-08-19

    ... 600 and 50 CFR part 679. The 2010 rock sole TAC specified for the Bering Sea and Aleutian Islands ICA... Amendment 80 Allocations of The Aleutian Islands Pacific Ocean Perch, And BSAI Flathead Sole, Rock Sole, And.... 0910131363-0087-02] RIN 0648-XY29 Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Rock...

  12. Phonon conductivity and relaxation rate in solids with disturbances by the Green function method

    International Nuclear Information System (INIS)

    Singh, M.

    1980-09-01

    In this present article we have established an expression for the temperature dependence of the lattice thermal conductivity of solids with harmonic disturbances. The relaxation rate for scattering of phonons with point defect is also derived. We will apply the Kubo-correlation function formalism for the thermal conductivity, and the double time temperature dependent Green function technique for the evaluation of correlation functions

  13. Relaxation processes during amorphous metal alloys heating

    International Nuclear Information System (INIS)

    Malinochka, E.Ya.; Durachenko, A.M.; Borisov, V.T.

    1982-01-01

    Behaviour of Te+15 at.%Ge and Fe+13 at.%P+7 at.%C amorphous metal alloys during heating has been studied using the method of differential scanning calorimetry (DSC) as the most convenient one for determination of the value of heat effects, activation energies, temperature ranges of relaxation processes. Thermal effects corresponding to high-temperature relaxation processes taking place during amorphous metal alloys (AMA) heating are detected. The change of ratio of relaxation peaks values on DSC curves as a result of AMA heat treatment can be explained by the presence of a number of levels of inner energy in amorphous system, separated with potential barriers, the heights of which correspond to certain activation energies of relaxation processes

  14. Multiscale dipole relaxation in dielectric materials

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2016-01-01

    Dipole relaxation from thermally induced perturbations is investigated on different length scales for dielectric materials. From the continuum dynamical equations for the polarisation, expressions for the transverse and longitudinal dipole autocorrelation functions are derived in the limit where ...

  15. Generalized approach to non-exponential relaxation

    Indian Academy of Sciences (India)

    Non-exponential relaxation is a universal feature of systems as diverse as glasses, spin ... which changes from a simple exponential to a stretched exponential and a power law by increasing the constraints in the system. ... Current Issue

  16. Oxygen-17 relaxation in aqueous agarose gels

    International Nuclear Information System (INIS)

    Ablett, S.; Lillford, P.J.

    1977-01-01

    Nuclear magnetic relaxation of oxygen-17 in H 2 17 O enriched agarose gels shows that existing explanations of water behaviour are oversimplified. Satisfactory models must include at least three proton phases, two of which involve water molecules. (Auth.)

  17. Relaxation and hypnosis in pediatric dental patients.

    Science.gov (United States)

    Peretz, B

    1996-01-01

    Relaxation and hypnosis are methods which, may solve the problem of extreme dental anxiety, when all other methods, behavioral or pharmacological may not be used. A simple definition of hypnosis is suggestion and repetition. Suggestion is the process whereby an individual accepts a proposition put to him by another, without having the slightest logical reason for doing so. Relaxation is one method of inducing hypnosis. A case of using hypnosis on an 11-year-old boy is described.

  18. Ghost lines in Moessbauer relaxation spectra

    International Nuclear Information System (INIS)

    Price, D.C.

    1985-01-01

    The appearance in Moessbauer relaxation spectra of 'ghost' lines, which are narrow lines that do not correspond to transitions between real hyperfine energy levels of the resonant system, is examined. It is shown that in many cases of interest, the appearance of these 'ghost' lines can be interpreted in terms of the relaxational averaging of one or more of the static interactions of the ion. (orig.)

  19. Dynamics of helicity transport and Taylor relaxation

    International Nuclear Information System (INIS)

    Diamond, P.H.; Malkov, M.

    2003-01-01

    A simple model of the dynamics of Taylor relaxation is derived using symmetry principles alone. No statistical closure approximations are invoked or detailed plasma model properties assumed. Notably, the model predicts several classes of nondiffusive helicity transport phenomena, including traveling nonlinear waves and superdiffusive turbulent pulses. A universal expression for the scaling of the effective magnetic Reynolds number of a system undergoing Taylor relaxation is derived. Some basic properties of intermittency in helicity transport are examined

  20. Regularities of intermediate adsorption complex relaxation

    International Nuclear Information System (INIS)

    Manukova, L.A.

    1982-01-01

    The experimental data, characterizing the regularities of intermediate adsorption complex relaxation in the polycrystalline Mo-N 2 system at 77 K are given. The method of molecular beam has been used in the investigation. The analytical expressions of change regularity in the relaxation process of full and specific rates - of transition from intermediate state into ''non-reversible'', of desorption into the gas phase and accumUlation of the particles in the intermediate state are obtained

  1. Cross Relaxation in rare-earth-doped oxyfluoride glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lakshminarayana, G.; Weis, Eric M. [Materials Science and Technology Division (MST-7), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lira, A.C. [Unidad Académica Profesional Nezahualcóyotl, Universidad Autónoma del Estado de México, Av. Bordo de Xochiaca s/n, Nezahualcóyotl, Estado de Mexico 57000, México (Mexico); Caldiño, Ulises [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, México D.F. 09340 (Mexico); Williams, Darrick J. [Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hehlen, Markus P., E-mail: hehlen@lanl.gov [Materials Science and Technology Division (MST-7), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-07-15

    The excited-state relaxation dynamics of Tb{sup 3+}, Sm{sup 3+}, and Eu{sup 3+} doped into a 50SiO{sub 2}–20Al{sub 2}O{sub 3}–10Na{sub 2}O–20LaF{sub 3} (mol%) oxyfluoride glass are studied. Multiphonon relaxation of the primary emitting states in Tb{sup 3+} ({sup 5}D{sub 3} and {sup 5}D{sub 4}), Sm{sup 3+} ({sup 4}G{sub 5/2}), and Eu{sup 3+} ({sup 5}D{sub 0}) was found to be negligible in the present host. The relaxation of Tb{sup 3+} ({sup 5}D{sub 4}) and Eu{sup 3+} ({sup 5}D{sub 0}) is dominated by radiative decay. For Tb{sup 3+} ({sup 5}D{sub 3}) and Sm{sup 3+} ({sup 4}G{sub 5/2}) in contrast, radiative relaxation is in competition with several non-radiative cross-relaxation processes. This competition was found to be particularly pronounced for the {sup 5}D{sub 3} excited state in Tb{sup 3+}, where a 124-fold decrease of the ({sup 5}D{sub 3}→{sup 7}F{sub 5})/({sup 5}D{sub 4}→{sup 7}F{sub 5}) emission intensity ratio and a ∼10-fold shortening of the {sup 5}D{sub 3} lifetime was observed upon increasing the Tb{sup 3+} concentration from 0.01% to 1%. The Tb{sup 3+} concentration dependence of {sup 5}D{sub 3} also points to some degree of ion aggregation in the “as quenched” glasses. A Judd–Ofelt intensity analysis was performed for Sm{sup 3+} and used to estimate the relative magnitude of {sup 4}G{sub 5/2} cross-relaxation processes. Four cross-relaxation processes in particular were identified to account for 92% of the total {sup 4}G{sub 5/2} non-radiative decay, and a 11% quantum efficiency was estimated for the {sup 4}G{sub 5/2} excited state. Non-exponentiality in the {sup 5}D{sub 0} decay of Eu{sup 3+} is evidence for several Eu{sup 3+} coordination environments in the glass host that manifest in different {sup 5}D{sub 0} decay constants because of the hypersensitivity of the {sup 5}D{sub 0}→{sup 7}F{sub 2} transition. -- Highlights: ► Tb{sup 3+}, Sm{sup 3+}, and Eu{sup 3+} were doped into a LaF{sub 3}-rich oxyfluoride glass. ► The

  2. F{sup 19} relaxation in non-magnetic hexafluorides; Contribution a l'etude de la relaxation des fluors dans les hexafluorures non magnetiques

    Energy Technology Data Exchange (ETDEWEB)

    Rigny, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-12-01

    The interesting properties of the fluorine magnetic resonance in the hexafluorides of molybdenum, tungsten and uranium, are very much due to large anisotropies of the chemical shift tensors. In the solid phases these anisotropies, the values of which are deduced from line shape studies, allow one to show that the molecules undergo hindered rotations about the metal atom. The temperature and frequency dependence of the fluorine longitudinal relaxation times shows that the relaxation is due to the molecular motion. The dynamical parameters of this motion are then deduced from the complete study of the fluorine relaxation in the rotating frame. In the liquid phases, the existence of anisotropies allows an estimation of the different contributions to the relaxation. In particular, the frequency and temperature dependence of the relaxation shows it to be dominated by the spin-rotation interaction. We have shown that the strength of this interaction can be deduced from the chemical shifts, and the angle through which the molecule rotates quasi-freely can be determined. In the hexafluorides, this angle is roughly one radian at 70 C, and with the help of this value, the friction coefficients which describe the intermolecular interactions are discussed. (author) [French] Les proprietes de la resonance magnetique des fluors dans les hexafluorures de molybdene, tungstene et uranium sont influencees par l'existence de deplacements chimiques tres anisotropes. Dans les phases solides, la valeur de cette anisotropie peut etre determinee par l'analyse des formes de raies et son existence permet de montrer que les molecules sont en rotation empechee autour de leur atome central. L'etude du temps de relaxation longitudinal en fonction de la temperature et de la frequence montre que la relaxation est due aux mouvements moleculaires, aux plus hautes temperatures. Les proprietes dynamiques du mouvement sont obtenues par l'etude complete de la relaxation spin-reseau dans le referentiel

  3. Reduced flocking by birds on islands with relaxed predation.

    Science.gov (United States)

    Beauchamp, Guy

    2004-05-22

    Adaptive hypotheses for the evolution of flocking in birds have usually focused on predation avoidance or foraging enhancement. It still remains unclear to what extent each factor has contributed to the evolution of flocking. If predation avoidance were the sole factor involved, flocking should not be prevalent when predation is relaxed. I examined flocking tendencies along with mean and maximum flock size in species living on islands where predation risk is either absent or negligible and then compared these results with matched counterparts on the mainland. The dataset consisted of 46 pairs of species from 22 different islands across the world. The tendency to flock was retained on islands in most species, but in pairs with dissimilar flocking tendencies, island species were less likely to flock. Mean and maximum flock size were smaller on islands than on the mainland. Potential confounding factors such as population density, nest predation, habitat type, food type and body mass failed to account for the results. The results suggest that predation is a significant factor in the evolution of flocking in birds. Nevertheless, predation and other factors, such as foraging enhancement, probably act together to maintain the trait in most species.

  4. A wrinkling-based method for investigating glassy polymer film relaxation as a function of film thickness and temperature.

    Science.gov (United States)

    Chung, Jun Young; Douglas, Jack F; Stafford, Christopher M

    2017-10-21

    We investigate the relaxation dynamics of thin polymer films at temperatures below the bulk glass transition T g by first compressing polystyrene films supported on a polydimethylsiloxane substrate to create wrinkling patterns and then observing the slow relaxation of the wrinkled films back to their final equilibrium flat state by small angle light scattering. As with recent relaxation measurements on thin glassy films reported by Fakhraai and co-workers, we find the relaxation time of our wrinkled films to be strongly dependent on film thickness below an onset thickness on the order of 100 nm. By varying the temperature between room temperature and T g (≈100 °C), we find that the relaxation time follows an Arrhenius-type temperature dependence to a good approximation at all film thicknesses investigated, where both the activation energy and the relaxation time pre-factor depend appreciably on film thickness. The wrinkling relaxation curves tend to cross at a common temperature somewhat below T g , indicating an entropy-enthalpy compensation relation between the activation free energy parameters. This compensation effect has also been observed recently in simulated supported polymer films in the high temperature Arrhenius relaxation regime rather than the glassy state. In addition, we find that the film stress relaxation function, as well as the height of the wrinkle ridges, follows a stretched exponential time dependence and the short-time effective Young's modulus derived from our modeling decreases sigmoidally with increasing temperature-both characteristic features of glassy materials. The relatively facile nature of the wrinkling-based measurements in comparison to other film relaxation measurements makes our method attractive for practical materials development, as well as fundamental studies of glass formation.

  5. Numerical modeling of bubble dynamics in viscoelastic media with relaxation

    Science.gov (United States)

    Warnez, M. T.; Johnsen, E.

    2015-06-01

    Cavitation occurs in a variety of non-Newtonian fluids and viscoelastic materials. The large-amplitude volumetric oscillations of cavitation bubbles give rise to high temperatures and pressures at collapse, as well as induce large and rapid deformation of the surroundings. In this work, we develop a comprehensive numerical framework for spherical bubble dynamics in isotropic media obeying a wide range of viscoelastic constitutive relationships. Our numerical approach solves the compressible Keller-Miksis equation with full thermal effects (inside and outside the bubble) when coupled to a highly generalized constitutive relationship (which allows Newtonian, Kelvin-Voigt, Zener, linear Maxwell, upper-convected Maxwell, Jeffreys, Oldroyd-B, Giesekus, and Phan-Thien-Tanner models). For the latter two models, partial differential equations (PDEs) must be solved in the surrounding medium; for the remaining models, we show that the PDEs can be reduced to ordinary differential equations. To solve the general constitutive PDEs, we present a Chebyshev spectral collocation method, which is robust even for violent collapse. Combining this numerical approach with theoretical analysis, we simulate bubble dynamics in various viscoelastic media to determine the impact of relaxation time, a constitutive parameter, on the associated physics. Relaxation time is found to increase bubble growth and permit rebounds driven purely by residual stresses in the surroundings. Different regimes of oscillations occur depending on the relaxation time.

  6. Relaxation Mechanisms, Structure and Properties of Semi-Coherent Interfaces

    Directory of Open Access Journals (Sweden)

    Shuai Shao

    2015-10-01

    Full Text Available In this work, using the Cu–Ni (111 semi-coherent interface as a model system, we combine atomistic simulations and defect theory to reveal the relaxation mechanisms, structure, and properties of semi-coherent interfaces. By calculating the generalized stacking fault energy (GSFE profile of the interface, two stable structures and a high-energy structure are located. During the relaxation, the regions that possess the stable structures expand and develop into coherent regions; the regions with high-energy structure shrink into the intersection of misfit dislocations (nodes. This process reduces the interface excess potential energy but increases the core energy of the misfit dislocations and nodes. The core width is dependent on the GSFE of the interface. The high-energy structure relaxes by relative rotation and dilatation between the crystals. The relative rotation is responsible for the spiral pattern at nodes. The relative dilatation is responsible for the creation of free volume at nodes, which facilitates the nodes’ structural transformation. Several node structures have been observed and analyzed. The various structures have significant impact on the plastic deformation in terms of lattice dislocation nucleation, as well as the point defect formation energies.

  7. Mechanisms of Coupled Vibrational Relaxation and Dissociation in Carbon Dioxide.

    Science.gov (United States)

    Armenise, Iole; Kustova, Elena

    2018-05-21

    A complete vibrational state-specific kinetic scheme describing dissociating carbon dioxide mixtures is proposed. CO 2 symmetric, bending and asymmetric vibrations and dissociation-recombination are strongly coupled through inter-mode vibrational energy transfers. Comparative study of state-resolved rate coefficients is carried out; the effect of different transitions may vary considerably with temperature. A non-equilibrium 1-D boundary layer flow typical to hypersonic planetary entry is studied in the state-to-state approach. To assess the sensitivity of fluid-dynamic variables and heat transfer to various vibrational transitions and chemical reactions, corresponding processes are successively included to the kinetic scheme. It is shown that vibrational-translational (VT) transitions in the symmetric and asymmetric modes do not alter the flow and can be neglected whereas the VT 2 exchange in the bending mode is the main channel of vibrational relaxation. Inter-mode vibrational exchanges affect the flow implicitly, through energy redistribution enhancing VT relaxation; the dominating role belongs to near-resonant transitions between symmetric and bending modes as well as between CO molecules and CO 2 asymmetric mode. Strong coupling between VT 2 relaxation and chemical reactions is emphasized. While vibrational distributions and average vibrational energy show strong dependence on the kinetic scheme, the heat flux is more sensitive to chemical reactions.

  8. Sedative and muscle relaxant activities of diterpenoids from Phlomidoschema parviflorum

    Directory of Open Access Journals (Sweden)

    Abdur Rauf

    Full Text Available Abstract Phlomidoschema parviflorum (Benth. Vved. (Basionym: Stachys parviflora Benth. Lamiaceae, have significance medicinal importance as it is used in number of health disorders including diarrhea, fever, sore mouth and throat, internal bleeding, weaknesses of the liver and heart genital tumors, sclerosis of the spleen, inflammatory tumors and cancerous ulcers. The present contribution deals with the sedative and muscle relaxant like effects of diterpenoids trivially named stachysrosane and stachysrosane, isolated from the ethyl acetate soluble fraction of P. parviflorum. Both compounds (at 5, 10 and 15 mg/kg, i.p were assessed for their in vivo sedative and muscle relaxant activity in open field and inclined plane test, respectively. The geometries of both compounds were optimized with density functional theory. The molecular docking of both compounds were performed with receptor gamma aminobutyric acid. Both compounds showed marked activity in a dose dependent manner. The docking studies showed that both compounds interact strongly with important residues in receptor gamma aminobutyric acid. The reported data demonstrate that both compounds exhibited significant sedative and muscle relaxant-like effects in animal models, which opens a door for novel therapeutic applications.

  9. Excitation relaxation and structure of TPPS4 J-aggregates

    International Nuclear Information System (INIS)

    Kelbauskas, L.; Bagdonas, S.; Dietel, W.; Rotomskis, R.

    2003-01-01

    The energy relaxation kinetics and the structure of the J-aggregates of water-soluble porphyrin 5,10,15,20-tetrasulphonatophenyl porphine (TPPS 4 ) were investigated in aqueous medium by means of time-resolved fluorescence spectroscopy and confocal laser-scanning fluorescence microscopy. The excitation of the J-aggregates, at excitation intensities higher than ∼10 15 photons/cm 2 per pulse, results in a remarkable decrease of the fluorescence quantum yield and in the appearance of an additional, non-exponential energy relaxation channel with a decay constant that depends on the excitation intensity. This relaxation mechanism was attributed to the exciton single-singlet annihilation. The exciton lifetime in the absence of the annihilation was calculated to be ∼150 ps. Using exciton annihilation theory, the exciton migration within the J-aggregates could be characterized by determining the exciton diffusion constant (1.8±0.9) 10 -3 cm 2 /s and the hopping time (1.2±0.6) ps. Using the experimental data, the size of the J-aggregate could be evaluated and was seen to yield at least 20 TPPS 4 molecules per aggregate. It was shown by means of confocal fluorescence laser scanning microscopy that TPPS 4 does self-associate in polyvinyl alcohol (PVA) at acidic pH forming molecular macro-assemblies on a scale of ∼1 μm in PVA matrices

  10. Transient absorption microscopy studies of energy relaxation in graphene oxide thin film.

    Science.gov (United States)

    Murphy, Sean; Huang, Libai

    2013-04-10

    Spatial mapping of energy relaxation in graphene oxide (GO) thin films has been imaged using transient absorption microscopy (TAM). Correlated AFM images allow us to accurately determine the thickness of the GO films. In contrast to previous studies, correlated TAM-AFM allows determination of the effect of interactions of GO with the substrate and between stacked GO layers on the relaxation dynamics. Our results show that energy relaxation in GO flakes has little dependence on the substrate, number of stacked layers, and excitation intensity. This is in direct contrast to pristine graphene, where these factors have great consequences in energy relaxation. This suggests intrinsic factors rather than extrinsic ones dominate the excited state dynamics of GO films.

  11. Transient absorption microscopy studies of energy relaxation in graphene oxide thin film

    International Nuclear Information System (INIS)

    Murphy, Sean; Huang, Libai

    2013-01-01

    Spatial mapping of energy relaxation in graphene oxide (GO) thin films has been imaged using transient absorption microscopy (TAM). Correlated AFM images allow us to accurately determine the thickness of the GO films. In contrast to previous studies, correlated TAM–AFM allows determination of the effect of interactions of GO with the substrate and between stacked GO layers on the relaxation dynamics. Our results show that energy relaxation in GO flakes has little dependence on the substrate, number of stacked layers, and excitation intensity. This is in direct contrast to pristine graphene, where these factors have great consequences in energy relaxation. This suggests intrinsic factors rather than extrinsic ones dominate the excited state dynamics of GO films. (paper)

  12. Measurements of spin-lattice relaxation time in mixed alkali halide crystals

    International Nuclear Information System (INIS)

    Tannus, A.

    1983-01-01

    Using magneto-optic techniques the ground state spin-lattice relaxation times (T1) of 'F' centers in mixed Alkali Halide cristals (KCl-KBr), was studied. A computer assisted system to optically measure short relaxation times (approx. = 1mS), was described. The technique is based on the measurement of the Magnetic Circular Dicroism (MCD) presented by F centers. The T1 magnetic field dependency at 2 K (up to 65 KGauss), was obtained as well as the MCD spectra for different relative concentration at the mixed matrices. The theory developed by Panepucci and Mollenauer for F centers spin-lattice relaxation in pure matrices was modified to explain the behaviour of T1 in mixed cristals. The Direct Process results (T approx. = 2.0 K) compared against that theory shows that the main relaxation mecanism, up to 25 KGauss, continues to be phonon modulation of the hiperfine iteraction between F electrons and surrounding nuclei. (Author) [pt

  13. In vivo antinociceptive and muscle relaxant activity of leaf and bark of Buddleja asiatica L.

    Science.gov (United States)

    Barkatullah, -; Ibrar, Muhammad; Ikram, Nazia; Rauf, Abdur; Hadda, Taibi Ben; Bawazeer, Saud; Khan, Haroon; Pervez, Samreen

    2016-09-01

    The current study was designed to assess the antinociceptive and skeleton muscle relaxant effect of leaves and barks of Buddleja asiatica in animal models. In acetic acid induced writhing test, pretreatment of ethanolic extract of leaves and barks evoked marked dose dependent antinociceptive effect with maximum of 70% and 67% pain relief at 300mg/kg i.p. respectively. In chimney test, the ethanolic extract of leaves and barks evoked maximum of 66.66% and 53.33% muscle relaxant effect after 90min of treatment at 300mg/kg i.p respectively. In traction test, the ethanolic extract of leaves and barks caused maximum of 60% and 73.33% muscle relaxant effect after 90min of treatment at 300mg/kg i.p respectively. In short, both leaves and barks demonstrated profound antinociceptive and skeleton muscle relaxant effects and thus the study provided natural healing agents for the treatment of said disorders.

  14. Spin relaxation in InGaN quantum disks in GaN nanowires

    KAUST Repository

    Banerjee, Animesh; Dog,; Heo, Junseok; Manchon, Aurelien; Guo, Wei; Bhattacharya, Pallab K.

    2011-01-01

    The spin relaxation time of photoinduced conduction electrons has been measured in InGaN quantum disks in GaN nanowires as a function of temperature and In composition in the disks. The relaxation times are of the order of ∼100 ps at 300 K and are weakly dependent on temperature. Theoretical considerations show that the Elliott-Yafet scattering mechanism is essentially absent in these materials and the results are interpreted in terms of the D'yakonov-Perel' relaxation mechanism in the presence of Rashba spin-orbit coupling of the wurtzite structure. The calculated spin relaxation times are in good agreement with the measured values. © 2011 American Chemical Society.

  15. Intrinsic spin-relaxation induced negative tunnel magnetoresistance in a single-molecule magnet

    Science.gov (United States)

    Xie, Haiqing; Wang, Qiang; Xue, Hai-Bin; Jiao, HuJun; Liang, J.-Q.

    2013-06-01

    We investigate theoretically the effects of intrinsic spin-relaxation on the spin-dependent transport through a single-molecule magnet (SMM), which is weakly coupled to ferromagnetic leads. The tunnel magnetoresistance (TMR) is obtained by means of the rate-equation approach including not only the sequential but also the cotunneling processes. It is shown that the TMR is strongly suppressed by the fast spin-relaxation in the sequential region and can vary from a large positive to slight negative value in the cotunneling region. Moreover, with an external magnetic field along the easy-axis of SMM, a large negative TMR is found when the relaxation strength increases. Finally, in the high bias voltage limit the TMR for the negative bias is slightly larger than its characteristic value of the sequential region; however, it can become negative for the positive bias caused by the fast spin-relaxation.

  16. Tensile, creep and relaxation characteristics of zircaloy cladding at 3850C

    International Nuclear Information System (INIS)

    Murty, K.L.; McDonald, S.G.

    1981-01-01

    Axial creep tests were carried out at stresses ranging form 30 ksi to 50 ksi. Steady-state creep rates were evaluated from stress change tests to minimize the number of samples. The secondary creep rate was related to the applied stress through a Sinh function. The functional dependence of the strain rate on the stress was also evaluated from load relaxation tests. It is demonstrated that the strain rates derived from load relaxation tests are identical to the creep data when the relaxation testing was carried out at the point of maximum load in a tensile test. In addition, the creep and relaxation results are identical to the true ultimate tensile stress versus applied strain-rate data derived from tensile tests. (orig./HP)

  17. Spin relaxation rates in quantum dots: Role of the phonon modulated spin orbit interaction

    Science.gov (United States)

    Alcalde, A. M.; Romano, C. L.; Marques, G. E.

    2008-11-01

    We calculate the spin relaxation rates in InAs and GaAs parabolic quantum dots due to the interaction of spin carriers with acoustical phonons. We consider a spin relaxation mechanism completely intrinsic to the system, since it is based on the modulation of the spin-orbit interaction by the acoustic phonon potential, which is independent of any structural properties of the confinement potential. The electron-phonon deformation potential and the piezoelectric interaction are described by the Pavlov-Firsov spin-phonon Hamiltonian. Our results demonstrate that, for narrow-gap semiconductors, the deformation potential interaction becomes dominant. This behavior is not observed for wide or intermediate gap semiconductors, where the piezoelectric coupling, in general, governs the relaxation processes. We also demonstrate that the spin relaxation rates are particularly sensitive to values of the Landé g-factor, which depend strongly on the spatial shape of the confinement.

  18. Quantifying NMR relaxation correlation and exchange in articular cartilage with time domain analysis

    Science.gov (United States)

    Mailhiot, Sarah E.; Zong, Fangrong; Maneval, James E.; June, Ronald K.; Galvosas, Petrik; Seymour, Joseph D.

    2018-02-01

    Measured nuclear magnetic resonance (NMR) transverse relaxation data in articular cartilage has been shown to be multi-exponential and correlated to the health of the tissue. The observed relaxation rates are dependent on experimental parameters such as solvent, data acquisition methods, data analysis methods, and alignment to the magnetic field. In this study, we show that diffusive exchange occurs in porcine articular cartilage and impacts the observed relaxation rates in T1-T2 correlation experiments. By using time domain analysis of T2-T2 exchange spectroscopy, the diffusive exchange time can be quantified by measurements that use a single mixing time. Measured characteristic times for exchange are commensurate with T1 in this material and so impacts the observed T1 behavior. The approach used here allows for reliable quantification of NMR relaxation behavior in cartilage in the presence of diffusive fluid exchange between two environments.

  19. Nuclear Spin relaxation mediated by Fermi-edge electrons in n-type GaAs

    Science.gov (United States)

    Kotur, M.; Dzhioev, R. I.; Kavokin, K. V.; Korenev, V. L.; Namozov, B. R.; Pak, P. E.; Kusrayev, Yu. G.

    2014-03-01

    A method based on the optical orientation technique was developed to measure the nuclear-spin lattice relaxation time T 1 in semiconductors. It was applied to bulk n-type GaAs, where T 1 was measured after switching off the optical excitation in magnetic fields from 400 to 1200 G at low (< 30 K) temperatures. The spin-lattice relaxation of nuclei in the studied sample with n D = 9 × 1016 cm-3 was found to be determined by hyperfine scattering of itinerant electrons (Korringa mechanism) which predicts invariability of T 1 with the change in magnetic field and linear dependence of the relaxation rate on temperature. This result extends the experimentally verified applicability of the Korringa relaxation law in degenerate semiconductors, previously studied in strong magnetic fields (several Tesla), to the moderate field range.

  20. Spin relaxation in InGaN quantum disks in GaN nanowires

    KAUST Repository

    Banerjee, Animesh

    2011-12-14

    The spin relaxation time of photoinduced conduction electrons has been measured in InGaN quantum disks in GaN nanowires as a function of temperature and In composition in the disks. The relaxation times are of the order of ∼100 ps at 300 K and are weakly dependent on temperature. Theoretical considerations show that the Elliott-Yafet scattering mechanism is essentially absent in these materials and the results are interpreted in terms of the D\\'yakonov-Perel\\' relaxation mechanism in the presence of Rashba spin-orbit coupling of the wurtzite structure. The calculated spin relaxation times are in good agreement with the measured values. © 2011 American Chemical Society.

  1. Effect of an Ethanol Extract of Scutellaria baicalensis on Relaxation in Corpus Cavernosum Smooth Muscle

    Directory of Open Access Journals (Sweden)

    Xiang Li

    2012-01-01

    Full Text Available Aims of study. The aim of the present study was to investigate whether an ethanol extract of Scutellaria baicalensis (ESB relaxes penile corpus cavernosum muscle in organ bath experiments. Materials and methods. Changes in tension of cavernous smooth muscle strips were determined by penile strip chamber model and in penile perfusion model. Isolated endothelium-intact rabbit corpus cavernosum was precontracted with phenylephrine (PE and then treated with ESB. Results. ESB relaxed penile smooth muscle in a dose-dependent manner, and this was inhibited by pre-treatment with NG-nitro-l-arginine methyl ester (l-NAME, a nitric oxide (NO synthase inhibitor, and 1H-[1, 2, 4]-oxadiazolo-[4,3-α]-quinoxalin-1-one (ODQ, a soluble guanylyl cyclase (sGC inhibitor. ESB-induced relaxation was significantly attenuated by pretreatment with tetraethylammonium (TEA, a nonselective K+ channel blocker, and charybdotoxin, a selective Ca2+-dependent K+ channel inhibitor. ESB increased the cGMP levels of rabbit corpus cavernosum in a concentration-dependent manner without changes in cAMP levels. In a perfusion model of penile tissue, ESB also relaxed penile corpus cavernosum smooth muscle in a dose-dependent manner. Conclusion. Taken together, these results suggest that ESB relaxed rabbit cavernous smooth muscle via the NO/cGMP system and Ca2+-sensitive K+ channels in the corpus cavernosum.

  2. Effect of extender oils on the stress relaxation behavior of thermoplastic vulcanizates

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The long term mechanical behavior of oil extended thermoplastic vulcanizates (TPV based on polypropylene (PP and acrylonitrile-butadiene rubber (NBR has been characterized by means of stress relaxation experiments. The morphology of TPV and the phase specific oil distribution which depend on the content and type of oil as well as on the mixing regime have been characterized by means of Atomic Force Microscopy (AFM, Dynamic Mechanical Thermal Analysis (DMTA and Differential Scanning Calorimetrie (DSC. The discussion of the stress relaxation behavior was carried out using the two-component model, which allows splitting the initial stress into two components: a thermal activated stress component and an athermal one. A master curve was created by shifting the relaxation curves vertically and horizontally towards the reference curve. The vertical shift factor bT is a function of the temperature dependence of the athermal stress components. It was found that the oil distribution strongly affects the athermal stress component which is related to the contribution of the structural changes, e.g. crystallinity of the PP phase and the average molecular weight between the crosslinks of the NBR phase. From the temperature dependence of the horizontal shift factor aT the main viscoelastic relaxation process was determined as the α-relaxation process of the crystalline PP phase. It is not dependent on the polarity and content of the oil as well as the mixing regime.

  3. Homogeneous magnetic relaxation in iron-yttrium garnets in the vicinity of a phase transition

    International Nuclear Information System (INIS)

    Luzyanin, I.D.; Khavronin, V.P.

    1977-01-01

    Results are presented of an experimental investigation of the dynamics of homogeneous magnetization during a phase transition of the second kind in iron-yttrium garnet (IYG) single crystals of various shapes. It is shown that homogeneous relaxation significantly depends on both the magnitude of 4πchisub(st) (chisub(st) is static magnetic susceptibility) as well as on the relation between the variable field frequency (at which the investigation is carried out) and the characteristic energies. It is shown that beginning from temperatures such as 4πchisub(st) approximately 1, the characteristic dipole interaction energy becomes frequency dependent; this indicates that in this case Lorentz coupling between the dynamic susceptibility and homogeneous relaxation time is invalid. This is a principle point in investigations of homogeneous relaxation by radio-frequency techniques. The temperature dependence of the homogeneous relaxation time and static susceptibility is determined in the exchange region. It is found that the phase transition in IYG involves anomalous phenomena which manifest in release and absorption of heat by a sample and in the appearance of additional singularities in the temperature dependence of the homogeneous relaxation time

  4. Nuclear spin-lattice relaxation in n -type insulating and metallic GaAs single crystals

    Science.gov (United States)

    Lu, J.; Hoch, M. J. R.; Kuhns, P. L.; Moulton, W. G.; Gan, Z.; Reyes, A. P.

    2006-09-01

    The coupling of electron and nuclear spins in n-GaAs changes significantly as the donor concentration n increases through the insulator-metal critical concentration nC˜1.2×1016cm-3 . The present measurements of the Ga71 relaxation rates W made as a function of magnetic field (1-13T) and temperature (1.5-300K) for semi-insulating GaAs and for three doped n-GaAs samples with donor concentrations n=5.9×1015 , 7×1016 , and 2×1018cm-3 , show marked changes in the relaxation behavior with n . Korringa-like relaxation is found in both metallic samples for T30K phonon-induced nuclear quadrupolar relaxation is dominant. The relaxation rate measurements permit determination of the electron probability density at Ga71 sites. A small Knight shift of -3.3ppm was measured on the most metallic (2×1018cm-3) sample using magic-angle spinning at room temperature. For the n=5.9×1015cm-3 sample, a nuclear relaxation model involving the Fermi contact hyperfine interaction, rapid spin diffusion, and exchange coupled local moments is proposed. While the relaxation rate behavior with temperature for the weakly metallic sample, n=7×1016cm-3 , is similar to that found for the just-insulating sample, the magnetic field dependence is quite different. For the 5.9×1015cm-3 sample, increasing the magnetic field leads to a decrease in the relaxation rate, while for the 7×1016cm-3 sample this results in an increase in the relaxation rate ascribed to an increase in the density of states at the Fermi level as the Landau level degeneracy is increased.

  5. NMR relaxation induced by iron oxide particles: testing theoretical models.

    Science.gov (United States)

    Gossuin, Y; Orlando, T; Basini, M; Henrard, D; Lascialfari, A; Mattea, C; Stapf, S; Vuong, Q L

    2016-04-15

    Superparamagnetic iron oxide particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of iron oxide particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.

  6. Electronic relaxation processes in polyatomic molecules. Progress report, October 1, 1975--September 30, 1976

    International Nuclear Information System (INIS)

    Lim, E.C.

    1976-09-01

    Excitation energy dependence of radiationless decay rate under collision-free conditions was utilized as a probe of intramolecular vibrational relaxation in tetracene and pentacene. The results give evidence of vibrational relaxation which competes with electronic relaxation. The substitution dependence of T 1 (nπ*) → S 0 radiationless transition in monocyclic diazines and the temperature dependence of S 1 non-radiative decay rate in alcoholic solutions of polycyclic monoazines indicate that the vibronic interaction between the lowest energy nπ* and ππ* states leads to a rapid radiationless deactivation of the lower of the two electronic states. Finally, a photon-counting spectrofluorometer of very high sensitivity was constructed, and it was used to record T 2 → T 1 fluorescence in bromoanthracenes and S 2 → S 1 fluorescence in azulene. These spectra represent the first bona-fide, or the most convincing, observation of fluorescence between excited electronic states

  7. Sole disorders in conventionally managed and organic dairy herds using different housing systems

    DEFF Research Database (Denmark)

    Vaarst, Mette; Hindhede, Jens; Enevoldsen, Carsten

    1998-01-01

    Records of claw trimmings were analyzed in seven organic and six conventional Danish herds (a total of 974 cows). The housing systems represented were tie stall systems, loose housing system with slatted floor (one organic herd), and deep litter systems (deep straw bedding). Occurrence of sole...... stage from 61 to 120 d post partum in cows of other dual purpose breeds was positively associated with the presence of sole ulcer in one leg only in first parity cows. The time of year for claw trimming was a risk factor for acute haemorrhage in first parity cows, with the period from December...

  8. Robust design in generelaised linear models for improving the quality of polyurethane soles

    Directory of Open Access Journals (Sweden)

    Castro, Armando Mares

    2015-11-01

    Full Text Available In a process that manufactures polyurethane soles by casting, a number of problems lead to different types of defects on the sole, causing significant economic losses for the company. In order to improve the product quality and decrease the number of defects, this study conducts an experimental design in the context of robust design. Since the response variable is binary, the statistical analysis was performed using generalised linear models. The operational methodology reduced the percentage of defects, while combining the experimental technique and control systems to achieve superior quality and a consequent reduction in costs.

  9. Application of nonlinear EPR and NMR responses on spin systems in structure and relaxation structures

    International Nuclear Information System (INIS)

    Polyakov, A.I.; Ryabikin, Yu.A.; Bitenbaev, M.M.

    2004-01-01

    Full text: In this work results of investigation of paramagnetic systems (irradiated polymers and crystals, plastic-deformed metals, systems with strong exchange interaction, etc.) by methods of nonlinear relaxation spectroscopy (NRS) are presented. The NRS theoretical grounds were developed in the earlier works. Later the technique was applied successfully to relaxation studies and when analyzing magnetic resonance complicated overlapping spectra. As in course of polymer system irradiation, basically, several type of paramagnetic defects are formed with close values of the g factors, these materials can be used to exemplify NRS capabilities. In this work we use samples of irradiated PMMA copolymers. Analysis of the PMMA spectra shows that several types of paramagnetic defects strongly differing in the spin-lattice relaxation times are formed in irradiated PMMA-based polymer composites. It is found that degradation of the composite physical and engineering characteristics is caused, mainly, by radiation-induced disintegration of macromolecules, following the chain reaction, which can be revealed by occurring lattice radical states. Another portion of work is devoted to NRS application to deterring influence of structural defects (impurity, dislocation, etc.) on variation in times of nuclear spin-lattice relaxation in metal systems. At this stage we managed, for the first time, to separate the distribution functions for spin-lattice relaxation (T l ) and relaxation of nuclear spin dipole-dipole interaction (T d ). It is shown that one can assess an extent of crystal defect by the dependence of T d =f(c). Also in this work the NRS methods are applied to analyze EPR spectra of polycrystalline solid systems where exchange interaction is strong. It is shown that these systems, as a rule, contain a complete set of spin assemblies having different relaxation times, and the spin assembly distribution over the relaxation time depends on the defect number and type in solid

  10. Peroxynitrite-induced relaxation in isolated canine cerebral arteries and mechanisms of action

    International Nuclear Information System (INIS)

    Li Jianfeng; Li Wenyan; Altura, Bella T.; Altura, Burton M.

    2004-01-01

    The present study was undertaken to determine the vascular actions of peroxynitrite (ONOO - ), the product of superoxide and nitric oxide (NO), in isolated canine cerebral arteries and to gain insight into its potential mechanisms of action. In the absence of any vasoactive agent, ONOO - (from 10 -7 to 10 -6 M) was able to reduce the basal tension. In prostaglandin F2α-precontracted canine basilar arterial rings, ONOO - elicited concentration-dependent relaxation at concentrations from 10 -8 to 10 -5 M. The effective concentrations producing approximately 50% maximal relaxation (EC 50 ) to ONOO - were 4.06 x 10 -6 and 4.12 x 10 -6 M in intact and denuded rings, respectively (P > 0.05). No significant differences in relaxation responses were found in ring preparations with or without endothelium (P > 0.05). The presence of either 5 μM methylene blue (MB) or 5 μM 1H-[1,2,4]oxadiazolo-[4,3-α]quinoxalin-1-one (ODQ) significantly inhibited the relaxations induced by ONOO - . Tetraethylammonium chloride (T-2265) significantly decreased the ONOO - -induced relaxations in a concentration-dependent manner. However, ONOO - had no effect on rings precontracted by high KCL (P > 0.05). Addition of low concentrations of calyculin A (50 nM) was able to abolish the ONOO - -induced relaxation. Furthermore, ONOO - significantly inhibited calcium-induced contractions of K + -depolarized canine cerebral rings in a concentration-related manner. Lastly, a variety of pharmacological agents and antagonists including L-NMMA, L-arginine, indomethacin, atropine, naloxone, diphenhydramine, cimetine, glibenclamide, haloperidol, etc., did not influence the relaxant effects of ONOO - on the rings. Our new results suggest that ONOO - -triggered relaxation, on canine cerebral arteries, is mediated by elevation of cyclic guanosine monophosphate (cGMP) levels, membrane hyperpolarization via K+ channel activation, activation of myosin light chain phosphatase activity, and interference with

  11. Defect relaxation in disordered materials

    International Nuclear Information System (INIS)

    Crandell, R.S.

    1989-01-01

    Using an exponential distribution of activation barriers, annealing data for metastable effects in hydrogenated amorphous silicon, a-Si:H, are quantitatively explained. This includes the stretched exponential time dependence of annealing and a Meyer-Neldel rule for the annealing time constant. An exponential distribution of annealing energies arises because defects are frozen in during growth at high temperature. Mechanisms that lead to an exponential distribution of annealing energies are weak bond-breaking and charge trapping

  12. Dielectric relaxation in AgI doped silver selenomolybdate glasses

    Science.gov (United States)

    Palui, A.; Shaw, A.; Ghosh, A.

    2016-05-01

    We report the study of dielectric properties of some silver ion conducting silver selenomolybdate mixed network former glasses in a wide frequency and temperature range. The experimental data have been analyzed in the framework of complex dielectric permittivity. The dielectric permittivity data have been well interpreted using the Cole-Cole function. The temperature dependence of relaxation time obtained from real part of dielectric permittivity data shows an Arrhenius behavior. The activation energy shows a decreasing trend with the increase of doping content. Values of stretched exponential parameter are observed to be independent of temperature and composition.

  13. Thermal stress relaxation in magnesium composites during thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Trojanova, Z.; Lukac, P. (Karlova Univ., Prague (Czech Republic)); Kiehn, J.; Kainer, K.U.; Mordike, B.L. (Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany))

    1998-01-01

    It has been shown that the internal friction of Mg - Saffil metal matrix composites can be influenced by thermal stresses, if MMCc are submitted to thermal cycling between room temperature and an upper temperature of cycling. These stresses can be accommodated by generation and motion of dislocations giving the formation of the microplastic zones. The thermal stress relaxation depends on the upper temperature of cycling, the volume fraction of reinforcement and the matrix composition and can result in plastic deformation and strain hardening of the matrix without applied stress. The internal friction measurements can be used for non destructive investigation of processes which influence the mechanical properties. (orig.)

  14. Observation of in-plane asymmetric strain relaxation during crystal growth and growth interruption in InGaAs/GaAs(001)

    International Nuclear Information System (INIS)

    Sasaki, Takuo; Shimomura, Kenichi; Kamiya, Itaru; Ohshita, Yoshio; Yamaguchi, Masafumi; Suzuki, Hidetoshi; Takahasi, Masamitu

    2012-01-01

    In-plane asymmetric strain relaxation in lattice-mismatched InGaAs/GaAs(001) heteroepitaxy is studied by in situ three-dimensional X-ray reciprocal space mapping. Repeating crystal growth and growth interruptions during measurements allows us to investigate whether the strain relaxation is limited at a certain thickness or saturated. We find that the degree of relaxation during growth interruption depends on both the film thickness and the in-plane directions. Significant lattice relaxation is observed in rapid relaxation regimes during interruption. This is a clear indication that relaxation is kinetically limited. In addition, relaxation along the [110] direction can saturate more readily than that along the [1-bar10] direction. We discuss this result in terms of the interaction between orthogonally aligned dislocations. (author)

  15. The effect of relaxation therapy on autonomic functioning, symptoms and daily functioning, in patients with chronic fatigue syndrome or fibromyalgia: a systematic review.

    Science.gov (United States)

    Meeus, Mira; Nijs, Jo; Vanderheiden, Tanja; Baert, Isabel; Descheemaeker, Filip; Struyf, Filip

    2015-03-01

    To establish the effects of relaxation therapy on autonomic function, pain, fatigue and daily functioning in patients with chronic fatigue syndrome or fibromyalgia. A systematic literature study was performed. Using specific keywords related to fibromyalgia or chronic fatigue syndrome and relaxation therapy, the electronic databases PubMed and Web of Science were searched. Included articles were assessed for their risk of bias and relevant information regarding relaxation was extracted. The review was conducted and reported according to the PRISMA-statement. Thirteen randomized clinical trials of sufficient quality were included, resulting in a total of 650 fibromyalgia patients (11 studies) and 88 chronic fatigue syndrome patients (3 studies). None of the studies reported effects on autonomic function. Six studies reported the effect of guided imagery on pain and daily functioning in fibromyalgia. The acute effect of a single session of guided imagery was studied in two studies and seems beneficial for pain relief. For other relaxation techniques (eg. muscle relaxation, autogenic training) no conclusive evidence was found for the effect on pain and functioning in fibromyalgia patients comparison to multimodal treatment programs. For fatigue a multimodal approach seemed better than relaxation, as shown in the sole three studies on chronic fatigue syndrome patients. There is moderate evidence for the acute effect of guided imagery on pain, although the content of the visualization is a matter of debate. Other relaxation formats and the effects on functionality and autonomic function require further study. © The Author(s) 2014.

  16. Use of relaxation skills in differentially skilled athletes.

    OpenAIRE

    Kudlackova, K.; Eccles, D. W.; Dieffenbach, K.

    2013-01-01

    Objectives: To examine the use of relaxation skills by differentially skilled athletes in relation to the deliberate practice framework. Design: Differentially skilled athletes completed a survey about their use of relaxation skills. Method: 150 athletes representing three skill levels (recreational, college, and professional) completed the deliberate relaxation for sport survey, which assessed relaxation on three deliberate practice dimensions (relevancy, concentration, and ...

  17. The use of (double) relaxation oscillation SQUIDs as a sensor

    NARCIS (Netherlands)

    van Duuren, M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, Jakob; Rogalla, Horst

    1997-01-01

    Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc

  18. The Relaxation of Some Classes of Variational Integrals with Pointwise Continuous-Type Gradient Constraints

    International Nuclear Information System (INIS)

    De Arcangelis, Riccardo; Zappale, Elvira

    2005-01-01

    Relaxation problems for a functional are analyzed. Identity and integral representation results are proved under continuity-type assumptions, together with the description of the common density by means of convexification arguments. Classical relaxation results are extended to the case of the continuous variable dependence, and the non-identity features described in the measurable dependence case are shown to be non-occurring. Proofs are based on the properties of certain limits of multi-functions, and on an approximation result for functions. Results in more general settings are also obtained

  19. Tibolone and its metabolites acutely relax rabbit coronary arteries in vitro

    DEFF Research Database (Denmark)

    Lund, Claus Otto; Nilas, Lisbeth; Pedersen, Susan Helene

    2004-01-01

    under curve (AUC). RESULTS: Tibolone and its metabolites induced a concentration-dependent vasodilatation comparable to that of 17 beta-estradiol with the rank of potency: 3 beta-OH-tibolone approximately = to tibolone>3 alpha-OH-tibolone>Delta 4-isomer (ANOVA). l-NAME partly inhibited the relaxation.......05, ANOVA). CONCLUSIONS: Our data indicate that the acute relaxation induced by tibolone and its metabolites in coronary arteries in vitro are probably mediated by endothelium independent inhibition of calcium channels but may also involve an endothelium-dependent mechanism via nitric oxide. The effect...

  20. Effects of de-oiled palm kernel cake based fertilizers on sole maize ...

    African Journals Online (AJOL)

    A study was conducted to determine the effect of de-oiled palm kernel cake based fertilizer formulations on the yield of sole maize and cassava crops. Two de-oiled palm kernel cake based fertilizer formulations A and B were compounded from different proportions of de-oiled palm kernel cake, urea, muriate of potash and ...

  1. Diurnal periodicity in the activity of the common sole, solea vulgaris quensel

    NARCIS (Netherlands)

    Kruuk, H.

    1963-01-01

    1. 1. The diurnal rhythm in the trawl catch of Solea vulgaris Quensel gave rise to this investigation into the diurnal activity rhythm of the fish. 2. 2. Periodicity in the food intake of the Sole in its natural habitat was studied by analyses of the contents of the intestines. Food intake

  2. 77 FR 23369 - Federal Acquisition Regulation; Justification and Approval of Sole-Source 8(a) Contracts

    Science.gov (United States)

    2012-04-18

    ... Business Administration (SBA) may not accept a sole- source 8(a) contract in excess of $20 million for... is no conflict with the law. Execution of the J&A prior to the SBA's initiation of contract... small number of businesses that have been awarded 8(a) contracts over the $20 million threshold may be...

  3. Use of thermography to monitor sole haemorrhages and temperature distribution over the claws of dairy cattle.

    Science.gov (United States)

    Wilhelm, K; Wilhelm, J; Fürll, M

    2015-02-07

    Subclinical laminitis, an early pathological event in the development of many claw diseases, is an important factor in the welfare and economics of high-producing dairy cows. However, the aetiology and pathogenesis of this complex claw disease are not well understood. The present study investigated to what extent thermographic examination of claws is able to give information about corium inflammation, and whether the technique may be used as a diagnostic tool for early detection of subclinical laminitis. Moreover, the temperature distribution over the individual main claws was investigated to obtain further knowledge about pressure distribution on the claws. For this purpose the claws of 123 cows were evaluated in the first week after calving as well as after the second month of lactation for presence of sole haemorrhages (a sign of subclinical laminitis). Furthermore, the ground contact area was analysed by thermography. Sole haemorrhages were significantly increased by the second month of lactation. Thermography showed clear differences between the claws of the front limbs and hindlimbs, as well as between lateral and medial claws. Although the distribution of sole haemorrhages was consistent with the pattern of the temperature distribution over the main claws, no clear correlation was found between the claw temperature after calving and the visible laminitis-like changes (sole haemorrhages) eight weeks later. British Veterinary Association.

  4. Population dynamics of Aphis gossypii Glover and in sole and intercropping systems of cotton and cowpea.

    Science.gov (United States)

    Fernandes, Francisco S; Godoy, Wesley A C; Ramalho, Francisco S; Garcia, Adriano G; Santos, Bárbara D B; Malaquias, José B

    2018-01-01

    Population dynamics of aphids have been studied in sole and intercropping systems. These studies have required the use of more precise analytical tools in order to better understand patterns in quantitative data. Mathematical models are among the most important tools to explain the dynamics of insect populations. This study investigated the population dynamics of aphids Aphis gossypii and Aphis craccivora over time, using mathematical models composed of a set of differential equations as a helpful analytical tool to understand the population dynamics of aphids in arrangements of cotton and cowpea. The treatments were sole cotton, sole cowpea, and three arrangements of cotton intercropped with cowpea (t1, t2 and t3). The plants were infested with two aphid species and were evaluated at 7, 14, 28, 35, 42, and 49 days after the infestations. Mathematical models were used to fit the population dynamics of two aphid species. There were good fits for aphid dynamics by mathematical model over time. The highest population peak of both species A. gossypii and A. craccivora was found in the sole crops, and the lowest population peak was found in crop system t2. These results are important for integrated management programs of aphids in cotton and cowpea.

  5. Plantar Sole Unweighting Alters the Sensory Transmission to the Cortical Areas

    Directory of Open Access Journals (Sweden)

    Laurence Mouchnino

    2017-05-01

    Full Text Available It is well established that somatosensory inputs to the cortex undergo an early and a later stage of processing. The later has been shown to be enhanced when the earlier transmission decreased. In this framework, mechanical factors such as the mechanical stress to which sensors are subjected when wearing a loaded vest are associated with a decrease in sensory transmission. This decrease is in turn associated with an increase in the late sensory processes originating from cortical areas. We hypothesized that unweighting the plantar sole should lead to a facilitation of the sensory transmission. To test this hypothesis, we recorded cortical somatosensory evoked potentials (SEPs of individuals following cutaneous stimulation (by mean of an electrical stimulation of the foot sole in different conditions of unweighting when standing still with eyes closed. To this end, the effective bodyweight (BW was reduced from 100% BW to 40% BW. Contrary to what was expected, we found an attenuation of sensory information when the BW was unweighted to 41% which was not compensated by an increase of the late SEP component. Overall these results suggested that the attenuation of sensory transmission observed in 40 BW condition was not solely due to the absence of forces acting on the sole of the feet but rather to the current relevance of the afferent signals related to the balance constraints of the task.

  6. Variation in the location of the shoe sole flexion point influences plantar loading patterns during gait

    NARCIS (Netherlands)

    van der Zwaard, B.C.; Vanwanseele, B.; Holtkamp, F.; van der Horst, H.E.; Elders, P.J.M.; Menz, H.B.

    2014-01-01

    Background: Several footwear design characteristics are known to have detrimental effects on the foot. However, one characteristic that has received relatively little attention is the point where the sole flexes in the sagittal plane. Several footwear assessment forms assume that this should ideally

  7. Variation in the location of the shoe sole flexion point influences plantar loading patterns during gait

    NARCIS (Netherlands)

    H. van der Horst; H.B. Menz; ing., M.Sc F.C. Holtkamp; P. Elders; B. Vanwanseele; B. van der Zwaard

    2014-01-01

    Background Several footwear design characteristics are known to have detrimental effects on the foot. However, one characteristic that has received relatively little attention is the point where the sole flexes in the sagittal plane. Several footwear assessment forms assume that this should ideally

  8. Effects of climate change on growth of 0-group sole and plaice

    NARCIS (Netherlands)

    Teal, L.R.; Leeuw, de J.J.; Veer, van der H.W.; Rijnsdorp, A.D.

    2008-01-01

    The effect of rising seawater temperature on growth of 0-group sole Solea solea and plaice Pleuronectes platessa in the southeastern North Sea was investigated for the period 1970 to 2004 using annual autumn pre-recruit survey data and frequent surveys on a nursery ground. Autumn length showed an

  9. Retrospective analysis of the treatment of psoriasis of the palms and soles

    NARCIS (Netherlands)

    Spuls, P. I.; Hadi, S.; Rivera, L.; Lebwohl, M.

    2003-01-01

    In this retrospective analysis, the effect of currently used treatments in 26 patients with psoriasis of the palms and soles were analyzed. In general, patients are treated initially with topical medications including superpotent topical corticosteroids in combination with calcipotriene ointment or

  10. Craniocervical Junction Meningiomas without Hydrocephalus Presenting Solely with Syncope: Report of 2 Cases.

    Science.gov (United States)

    Champagne, Pierre-Olivier; Bojanowski, Michel W

    2018-06-01

    To our knowledge, there have not been any reported cases of a meningioma of the craniocervical region presenting solely with syncope as its initial symptom. Only 1 case of meningioma presenting with syncope has been published, but it was associated with hydrocephalus. We report 2 cases of syncope caused by a craniocervical junction meningioma, with syncope being the sole presenting symptom and without hydrocephalus. We discuss the possible pathophysiology, as well as the clinical relevance of this type of presentation. We reviewed the charts, operative details, and imagery of 2 cases of meningioma in the region of the craniocervical junction, with syncope as their sole presenting feature. We also reviewed the literature. In 1 case the syncope occurred spontaneously. In the other, it occurred during a Valsalva maneuver. Both meningiomas were surgically removed via a retromastoid approach. There was no recurrence of syncope following surgery. Following a literature review, we found 1 case of posterior fossa meningioma presenting with syncope, but hydrocephalus was also present. Syncope can be the sole manifestation of a meningioma of the craniocervical junction. Such syncopes are a consequence of transient dysfunction of the autonomous pathways in the medulla and/or of the medulla's output. In the absence of other causes of syncope, a meningioma in this region, even in the absence of hydrocephalus, should not be considered as fortuitous, but rather as the actual cause of syncope. Recognizing this possibility offers the potential for proper diagnosis and appropriate treatment of the syncope. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Shoe sole tread designs and outcomes of slipping and falling on slippery floor surfaces.

    Directory of Open Access Journals (Sweden)

    Li-Wen Liu

    Full Text Available A gait experiment was conducted under two shoe sole and three floor conditions. The shoe soles and floors were characterized by the tread and groove designs on the surface. The coefficients of friction (COF on the floor in the target area were measured. The subjects were required to walk on a walkway and stepping on a target area covered with glycerol. The motions of the feet of the subjects were captured. Gait parameters were calculated based on the motion data. Among the 240 trials, there were 37 no-slips, 81 microslips, 45 slides, and 77 slips. It was found that the condition with shoe sole and floor had both tread grooves perpendicular to the walking direction had the highest COF, the shortest slip distance, and the lowest percentages of slide and slip. The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions. The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001, 0.33 (p<0.0001, -0.54 (p<0.0001, and -0.51 (p<0.0001, respectively.

  12. A Mole in the Sole: Case Report on Eccrine Poroma | Das | Internet ...

    African Journals Online (AJOL)

    Eccrine poroma is a benign tumor which arises from the intraepidermal portion of the eccrine sweat glands. 81 year old diabetic grandma worried about her persistently uncontrolled blood sugar owing to a painless mole in the sole of right foot for 2 years. Excisional biopsy revealed a sweat duct benign eccrine poroma.

  13. Toward developing recombinant gonadotropin-based hormone therapies for increasing fertility in the flatfish Senegalese sole.

    Directory of Open Access Journals (Sweden)

    François Chauvigné

    Full Text Available Captive flatfishes, such as the Senegalese sole, typically produce very low volumes of sperm. This situation is particularly prevalent in the first generation (F1 of reared sole males, which limits the development of artificial fertilization methods and the implementation of selective breeding programs. In this study, we investigated whether combined treatments with homologous recombinant follicle-stimulating (rFsh and luteinizing (rLh hormones, produced in a mammalian host system, could stimulate spermatogenesis and enhance sperm production in Senegalese sole F1 males. In an initial autumn/winter experiment, weekly intramuscular injections with increasing doses of rFsh over 9 weeks resulted in the stimulation of gonad weight, androgen release, germ cell proliferation and entry into meiosis, and the expression of different spermatogenesis-related genes, whereas a subsequent single rLh injection potentiated spermatozoa differentiation. In a second late winter/spring trial corresponding to the sole's natural prespawning and spawning periods, we tested the effect of repeated rLh injections on the amount and quality of sperm produced by males previously treated with rFsh for 4, 6, 8 or 10 weeks. These latter results showed that the combination of rFsh and rLh treatments could increase sperm production up to 7 times, and slightly improve the motility of the spermatozoa, although a high variability in the response was found. However, sustained administration of rFsh during spawning markedly diminished Leydig cell survival and the steroidogenic potential of the testis. These data suggest that in vivo application of rFsh and rLh is effective at stimulating spermatogenesis and sperm production in Senegalese sole F1 males, setting the basis for the future establishment of recombinant gonadotropin-based hormone therapies to ameliorate reproductive dysfunctions of this species.

  14. Mozart versus new age music: relaxation states, stress, and ABC relaxation theory.

    Science.gov (United States)

    Smith, Jonathan C; Joyce, Carol A

    2004-01-01

    Smith's (2001) Attentional Behavioral Cognitive (ABC) relaxation theory proposes that all approaches to relaxation (including music) have the potential for evoking one or more of 15 factor-analytically derived relaxation states, or "R-States" (Sleepiness, Disengagement, Rested / Refreshed, Energized, Physical Relaxation, At Ease/Peace, Joy, Mental Quiet, Childlike Innocence, Thankfulness and Love, Mystery, Awe and Wonder, Prayerfulness, Timeless/Boundless/Infinite, and Aware). The present study investigated R-States and stress symptom-patterns associated with listening to Mozart versus New Age music. Students (N = 63) were divided into three relaxation groups based on previously determined preferences. Fourteen listened to a 28-minute tape recording of Mozart's Eine Kleine Nachtmusik and 14 listened to a 28-minute tape of Steven Halpern's New Age Serenity Suite. Others (n = 35) did not want music and instead chose a set of popular recreational magazines. Participants engaged in their relaxation activity at home for three consecutive days for 28 minutes a session. Before and after each session, each person completed the Smith Relaxation States Inventory (Smith, 2001), a comprehensive questionnaire tapping 15 R-States as well as the stress states of somatic stress, worry, and negative emotion. Results revealed no differences at Session 1. At Session 2, those who listened to Mozart reported higher levels of At Ease/Peace and lower levels of Negative Emotion. Pronounced differences emerged at Session 3. Mozart listeners uniquely reported substantially higher levels of Mental Quiet, Awe and Wonder, and Mystery. Mozart listeners reported higher levels, and New Age listeners slightly elevated levels, of At Ease/Peace and Rested/Refreshed. Both Mozart and New Age listeners reported higher levels of Thankfulness and Love. In summary, those who listened to Mozart's Eine Kleine Nachtmusik reported more psychological relaxation and less stress than either those who listened to

  15. Asymptotic representation of relaxation oscillations in lasers

    CERN Document Server

    Grigorieva, Elena V

    2017-01-01

    In this book we analyze relaxation oscillations in models of lasers with nonlinear elements controlling light dynamics. The models are based on rate equations taking into account periodic modulation of parameters, optoelectronic delayed feedback, mutual coupling between lasers, intermodal interaction and other factors. With the aim to study relaxation oscillations we present the special asymptotic method of integration for ordinary differential equations and differential-difference equations. As a result, they are reduced to discrete maps. Analyzing the maps we describe analytically such nonlinear phenomena in lasers as multistability of large-amplitude relaxation cycles, bifurcations of cycles, controlled switching of regimes, phase synchronization in an ensemble of coupled systems and others. The book can be fruitful for students and technicians in nonlinear laser dynamics and in differential equations.

  16. Relaxation of the magnetization in magnetic molecules

    Science.gov (United States)

    Carretta, S.; Bianchi, A.; Liviotti, E.; Santini, P.; Amoretti, G.

    2006-04-01

    Several mechanisms characterize the relaxation dynamics in magnetic molecules. We investigate two of them, spin-lattice coupling and incoherent quantum tunneling. The effect of the phonon heat bath is studied by analyzing the exponential time decay of the autocorrelation of the magnetization. We show that in ferromagnetic (Cu6) and antiferromagnetic (Fe6) molecular rings this decay is characterized by a single characteristic time. At very low temperature, relaxation through incoherent quantum tunneling may occur in nanomagnets such as Fe8 or Ni4. The mixing between levels with different values of the total spin (S mixing) greatly influences this mechanism. In particular, we demonstrate that a fourth-order anisotropy term O44, required to interpret experimental electron paramagnetic resonance and relaxation data in Ni4, naturally arises when S mixing is considered in calculations.

  17. Relaxation oscillation logic in Josephson junction circuits

    International Nuclear Information System (INIS)

    Fulton, T.A.

    1981-01-01

    A dc powered, self-resetting Josephson junction logic circuit relying on relaxation oscillations is described. A pair of Josephson junction gates are connected in series, a first shunt is connected in parallel with one of the gates, and a second shunt is connected in parallel with the series combination of gates. The resistance of the shunts and the dc bias current bias the gates so that they are capable of undergoing relaxation oscillations. The first shunt forms an output line whereas the second shunt forms a control loop. The bias current is applied to the gates so that, in the quiescent state, the gate in parallel with the second shunt is at V O, and the other gate is undergoing relaxation oscillations. By controlling the state of the first gate with the current in the output loop of another identical circuit, the invert function is performed

  18. Improved memristor-based relaxation oscillator

    KAUST Repository

    Mosad, Ahmed G.

    2013-09-01

    This paper presents an improved memristor-based relaxation oscillator which offers higher frequency and wider tunning range than the existing reactance-less oscillators. It also has the capability of operating on two positive supplies or alternatively a positive and negative supply. Furthermore, it has the advantage that it can be fully integrated on-chip providing an area-efficient solution. On the other hand, The oscillation concept is discussed then a complete mathematical analysis of the proposed oscillator is introduced. Furthermore, the power consumption of the new relaxation circuit is discussed and validated by the PSPICE circuit simulations showing an excellent agreement. MATLAB results are also introduced to demonstrate the resistance range and the corresponding frequency range which can be obtained from the proposed relaxation oscillator. © 2013 Elsevier Ltd.

  19. Relaxation and Diffusion in Complex Systems

    CERN Document Server

    Ngai, K L

    2011-01-01

    Relaxation and Diffusion in Complex Systems comprehensively presents a variety of experimental evidences of universal relaxation and diffusion properties in complex materials and systems. The materials discussed include liquids, glasses, colloids, polymers, rubbers, plastic crystals and aqueous mixtures, as well as carbohydrates, biomolecules, bioprotectants and pharmaceuticals. Due to the abundance of experimental data, emphasis is placed on glass-formers and the glass transition problem, a still unsolved problem in condensed matter physics and chemistry. The evidence for universal properties of relaxation and diffusion dynamics suggests that a fundamental physical law is at work. The origin of the universal properties is traced to the many-body effects of the interaction, rigorous theory of which does not exist at the present time. However, using solutions of simplified models as guides, key quantities have been identified and predictions of the universal properties generated. These predictions from Ngai’...

  20. Electron relaxation properties of Ar magnetron plasmas

    Science.gov (United States)

    Xinjing, CAI; Xinxin, WANG; Xiaobing, ZOU

    2018-03-01

    An understanding of electron relaxation properties in plasmas is of importance in the application of magnetrons. An improved multi-term approximation of the Boltzmann equation is employed to study electron transport and relaxation properties in plasmas. Elastic, inelastic and nonconservative collisions between electrons and neutral particles are considered. The expressions for the transport coefficients are obtained using the expansion coefficients and the collision operator term. Numerical solutions of the matrix equations for the expansion coefficients are also investigated. Benchmark calculations of the Reid model are presented to demonstrate the accuracy of the improved multi-term approximation. It is shown that the two-term approximation is generally not accurate enough and the magnetic fields can reduce the anisotropy of the velocity distribution function. The electron relaxation properties of Ar plasmas in magnetrons for various magnetic fields are studied. It is demonstrated that the energy parameters change more slowly than the momentum parameters.

  1. ENERGY RELAXATION OF HELIUM ATOMS IN ASTROPHYSICAL GASES

    International Nuclear Information System (INIS)

    Lewkow, N. R.; Kharchenko, V.; Zhang, P.

    2012-01-01

    We report accurate parameters describing energy relaxation of He atoms in atomic gases, important for astrophysics and atmospheric science. Collisional energy exchange between helium atoms and atomic constituents of the interstellar gas, heliosphere, and upper planetary atmosphere has been investigated. Energy transfer rates, number of collisions required for thermalization, energy distributions of recoil atoms, and other major parameters of energy relaxation for fast He atoms in thermal H, He, and O gases have been computed in a broad interval of energies from 10 meV to 10 keV. This energy interval is important for astrophysical applications involving the energy deposition of energetic atoms and ions into atmospheres of planets and exoplanets, atmospheric evolution, and analysis of non-equilibrium processes in the interstellar gas and heliosphere. Angular- and energy-dependent cross sections, required for an accurate description of the momentum-energy transfer, are obtained using ab initio interaction potentials and quantum mechanical calculations for scattering processes. Calculation methods used include partial wave analysis for collisional energies below 2 keV and the eikonal approximation at energies higher than 100 eV, keeping a significant energy region of overlap, 0.1-2 keV, between these two methods for their mutual verification. The partial wave method and the eikonal approximation excellently match results obtained with each other as well as experimental data, providing reliable cross sections in the astrophysically important interval of energies from 10 meV to 10 keV. Analytical formulae, interpolating obtained energy- and angular-dependent cross sections, are presented to simplify potential applications of the reported database. Thermalization of fast He atoms in the interstellar gas and energy relaxation of hot He and O atoms in the upper atmosphere of Mars are considered as illustrative examples of potential applications of the new database.

  2. Multi-Phonon Relaxation of H^- Local Modes in CaF_2

    Science.gov (United States)

    Davison, C. P.; Happek, U.; Campbell, J. A.; Engholm, J. R.; Schwettman, H. A.

    1998-03-01

    Local modes play an important role in the relaxation of vibrational modes of small molecules in solids (J.R. Engholm, C.W. Rella, H.A. Schwettman, and U. Happek; Phys. Rev. Lett. 77), 1302 (1996)., but only few attempts have been reported to study the relaxation of these local modes. Here we report on experiments to investigate the non-radiative relaxation of H^- local modes in CaF_2. Using a pump-probe technique, saturation experiments on the H^- local modes, both interstitial and substitutional, were performed at the Stanford Free Electron Laser Center. At low temperature we find a relaxation time T1 of 45 psec for the substitutional H^- local mode, and a more rapid relaxation for the interstitial H^- local modes next to La^3+ and Lu^3+ impurities. Information on the decay channels of the local modes are obtained from the characteristic temperature dependence of the relaxation rates. This work is supported in part by the ONR, Grant No. N00014-94-1024.

  3. Effect of Temper Condition on Stress Relaxation Behavior of an Aluminum Copper Lithium Alloy

    Science.gov (United States)

    Mishra, Sumeet; Beura, Vikrant Kumar; Singh, Amit; Yadava, Manasij; Nayan, Niraj

    2018-04-01

    Deformation behavior of an Al-Cu-Li alloy in different temper conditions (solutionized and T8) is investigated using stress relaxation tests. Fundamental parameters such as the apparent and physical activation volume, strain rate sensitivity, effective stress, and exhaustion rate of mobile dislocation density are determined from single and multiple relaxation tests. It was found that dislocation-dislocation interaction controls the kinetics of plastic deformation in the solutionized sample, whereas dislocation-precipitate interaction is the overriding factor in the presence of T1 precipitates. The apparent activation volume was found to be significantly lower in the presence of T1 precipitates compared with solutionized samples. Strain rate sensitivity and effective stress were found to be higher in the presence of T1 precipitates. In addition, multiple relaxation tests showed that irrespective of microstructural features (solutes, semi-coherent precipitates), the mobile dislocation density reduces during the relaxation period. Further evidence regarding reduction in mobile dislocation density is obtained from uniaxial tensile tests carried out after stress relaxation tests, where both solutionized and T8 samples show an increase in strength. Additional discussion on relaxation strain is included to provide a complete overview regarding the time-dependent deformation behavior of the Al-Cu-Li alloy in different temper conditions.

  4. Relaxation study of a paramagnetic ion by the observation of nuclear resonance signals

    International Nuclear Information System (INIS)

    Landesman, A.

    1960-01-01

    Dynamic polarization of protons in water containing the paramagnetic ion NO(SO 3 ) 2 was studied, both theoretically and experimentally, as a function of magnetic field. The enhancement of the proton polarization depends appreciably on the relaxation process of the electron spin and so enables us to decide which is the real relaxation process. We tried the two following processes: a) The electron spin is coupled with the nitrogen magnetic moment by hyperfine interaction; if this interaction has an anisotropic part, a relaxation process for the electronic spin will result through the Brownian motion of the ion. b) The relaxation of the electron spin takes place through spin-orbit coupling of the electron spin. Experimental results showed that the relaxation took place through the second process with the help of dynamic polarization we were able to study the relaxation of an electron spin in a liquid without using any electron resonance spectrometer, simply by observing the resonance of a nuclear spin coupled with the electron spin. Reprint of a paper published in Le Journal de Physique et le Radium, t. 20, p. 937-948, 1959 [fr

  5. Strain relaxation and ambipolar electrical transport in GaAs/InSb core-shell nanowires.

    Science.gov (United States)

    Rieger, Torsten; Zellekens, Patrick; Demarina, Natalia; Hassan, Ali Al; Hackemüller, Franz Josef; Lüth, Hans; Pietsch, Ullrich; Schäpers, Thomas; Grützmacher, Detlev; Lepsa, Mihail Ion

    2017-11-30

    The growth, crystal structure, strain relaxation and room temperature transport characteristics of GaAs/InSb core-shell nanowires grown using molecular beam epitaxy are investigated. Due to the large lattice mismatch between GaAs and InSb of 14%, a transition from island-based to layer-like growth occurs during the formation of the shell. High resolution transmission electron microscopy in combination with geometric phase analyses as well as X-ray diffraction with synchrotron radiation are used to investigate the strain relaxation and prove the existence of different dislocations relaxing the strain on zinc blende and wurtzite core-shell nanowire segments. While on the wurtzite phase only Frank partial dislocations are found, the strain on the zinc blende phase is relaxed by dislocations with perfect, Shockley partial and Frank partial dislocations. Even for ultrathin shells of about 2 nm thickness, the strain caused by the high lattice mismatch between GaAs and InSb is relaxed almost completely. Transfer characteristics of the core-shell nanowires show an ambipolar conductance behavior whose strength strongly depends on the dimensions of the nanowires. The interpretation is given based on an electronic band profile which is calculated for completely relaxed core/shell structures. The peculiarities of the band alignment in this situation implies simultaneously occupied electron and hole channels in the InSb shell. The ambipolar behavior is then explained by the change of carrier concentration in both channels by the gate voltage.

  6. Spin Relaxation in III-V Semiconductors in various systems: Contribution of Electron-Electron Interaction

    Science.gov (United States)

    Dogan, Fatih; Kesserwan, Hasan; Manchon, Aurelien

    2015-03-01

    In spintronics, most of the phenomena that we are interested happen at very fast time scales and are rich in structure in time domain. Our understanding, on the other hand, is mostly based on energy domain calculations. Many of the theoretical tools use approximations and simplifications that can be perceived as oversimplifications. We compare the structure, material, carrier density and temperature dependence of spin relaxation time in n-doped III-V semiconductors using Elliot-Yafet (EY) and D'yakanov-Perel'(DP) with real time analysis using kinetic spin Bloch equations (KSBE). The EY and DP theories fail to capture details as the system investigated is varied. KSBE, on the other hand, incorporates all relaxation sources as well as electron-electron interaction which modifies the spin relaxation time in a non-linear way. Since el-el interaction is very fast (~ fs) and spin-conserving, it is usually ignored in the analysis of spin relaxation. Our results indicate that electron-electron interaction cannot be neglected and its interplay with the other (spin and momentum) relaxation mechanisms (electron-impurity and electron-phonon scattering) dramatically alters the resulting spin dynamics. We use each interaction explicitly to investigate how, in the presence of others, each relaxation source behaves. We use GaAs and GaN for zinc-blend structure, and GaN and AlN for the wurtzite structure.

  7. Mechanical torques generated by optically pumped atomic spin relaxation at surfaces

    International Nuclear Information System (INIS)

    Herman, R.M.

    1982-01-01

    It is argued that a valuable method of observing certain types of surface-atom interactions may lie in mechanical torques generated through the spin-orbit relaxation of valence electronic spins of optically pumped atoms at surfaces. The unusual feature of this phenomenon is that the less probable spin-orbit relaxation becomes highly visible as compared with the much more rapid paramagnetic relaxation, because of an enhancement, typically by as much as a factor 10 9 , in the torques delivered to mechanical structures, by virtue of a very large effective moment arm. Spin-orbit relaxation operates through an exchange of translational momentum which, in turn, can be identified with the delivery of a gigantic angular momentum (in units of h) relative to a distant axis about which mechanical motion is referred. The spin-orbit relaxation strongly depends upon the atomic number of the surface atoms and the strength of interaction with the optically pumped atoms. Being dominated by high-atomic-number surface atoms, spin-orbit relaxation rates may not be too strongly influenced by minor surface contamination of lighter-weight optically active atoms

  8. Mechanical torques generated by optically pumped atomic spin relaxation at surfaces

    Science.gov (United States)

    Herman, R. M.

    1982-03-01

    It is argued that a valuable method of observing certain types of surface-atom interactions may lie in mechanical torques generated through the spin-orbit relaxation of valence electronic spins of optically pumped atoms at surfaces. The unusual feature of this phenomenon is that the less probable spin-orbit relaxation becomes highly visible as compared with the much more rapid paramagnetic relaxation, because of an enhancement, typically by as much as a factor 109, in the torques delivered to mechanical structures, by virtue of a very large effective moment arm. Spin-orbit relaxation operates through an exchange of translational momentum which, in turn, can be identified with the delivery of a gigantic angular momentum (in units of ℏ) relative to a distant axis about which mechanical motion is referred. The spin-orbit relaxation strongly depends upon the atomic number of the surface atoms and the strength of interaction with the optically pumped atoms. Being dominated by high-atomic-number surface atoms, spin-orbit-relaxation rates may not be too strongly influenced by minor surface contamination of lighter-weight optically active atoms.

  9. Intra-well relaxation process in magnetic fluids subjected to strong polarising fields

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.N., E-mail: cmarin@physics.uvt.ro [West University of Timisoara, Faculty of Physics, B-dul V. Parvan, No. 4, Timisoara 300223 (Romania); Fannin, P.C. [Department of Electronic and Electrical Engineering, Trinity College, Dublin 2 (Ireland); Malaescu, I.; Barvinschi, P.; Ercuta, A. [West University of Timisoara, Faculty of Physics, B-dul V. Parvan, No. 4, Timisoara 300223 (Romania)

    2012-02-15

    We report on the frequency and field dependent complex magnetic susceptibility measurements of a kerosene-based magnetic fluid with iron oxide nanoparticles, stabilized with oleic acid, in the frequency range 0.1-6 GHz and over the polarising field range of 0-168.4 kA/m. By increasing polarising field, H, a subsidiary loss-peak clearly occurs in the vicinity of the ferromagnetic resonance peak, from which it remains distinct even in strong polarising fields of 168.4 kA/m. This is in contrast to other reported cases in which the intra-well relaxation process is manifested only as a shoulder of the resonance peak, which vanishes in polarising fields larger than that of 100 kA/m. The results of the XRD analysis connected to the anisotropy field results confirm that the investigated sample contains particles of magnetite and of the tetragonal phase of maghemite. Taking into account the characteristics of our sample, the theoretical analysis revealed that the intra-well relaxation process of the small particles of the tetragonal phase of maghemite may be responsible for the subsidiary loss peak of the investigated magnetic fluid. - Highlights: > Intra-well relaxation process in a magnetic fluid is studied. > Sample consists of the tetragonal phase of maghemite and magnetite particles. > A subsidiary relaxation peak is observed in the vicinity of the resonance peak. > Relaxation peak is correlated to the intra-well relaxation process. > It is assigned to the tetragonal phase of maghemite particles.

  10. A hierarchy of functionally important relaxations within myoglobin based on solvent effects, mutations and kinetic model.

    Science.gov (United States)

    Dantsker, David; Samuni, Uri; Friedman, Joel M; Agmon, Noam

    2005-06-01

    Geminate CO rebinding in myoglobin is studied for two viscous solvents, trehalose and sol-gel (bathed in 100% glycerol) at several temperatures. Mutations in key distal hemepocket residues are used to eliminate or enhance specific relaxation modes. The time-resolved data are analyzed with a modified Agmon-Hopfield model which is capable of providing excellent fits in cases where a single relaxation mode is dominant. Using this approach, we determine the relaxation rate constants of specific functionally important modes, obtaining also their Arrhenius activation energies. We find a hierarchy of distal pocket modes controlling the rebinding kinetics. The "heme access mode" (HAM) is responsible for the major slow-down in rebinding. It is a solvent-coupled cooperative mode which restricts ligand return from the xenon cavities. Bulky side-chains, like those His64 and Trp29 (in the L29W mutant), operate like overdamped pendulums which move over and block the binding site. They may be either unslaved (His64) or moderately slaved (Trp29) to the solvent. Small side-chain relaxations, most notably of leucines, are revealed in some mutants (V68L, V68A). They are conjectured to facilitate inter-cavity ligand motion. When all relaxations are arrested (H64L in trehalose), we observe pure inhomogeneous kinetics with no temperature dependence, suggesting that proximal relaxation is not a factor on the investigated timescale.

  11. The modified relaxation time function: A novel analysis technique for relaxation processes. Application to high-temperature molybdenum internal friction peaks

    International Nuclear Information System (INIS)

    Matteo, C.L.; Lambri, O.A.; Zelada-Lambri, G.I.; Sorichetti, P.A.; Garcia, J.A.

    2008-01-01

    The modified relaxation time (MRT) function, which is based on a general linear viscoelastic formalism, has several important mathematical properties that greatly simplify the analysis of relaxation processes. In this work, the MRT is applied to the study of the relaxation damping peaks in deformed molybdenum at high temperatures. The dependence of experimental data from these relaxation processes with temperature are adequately described by a Havriliak-Negami (HN) function, and the MRT makes it possible to find a relation between the parameters of the HN function and the activation energy of the process. The analysis reveals that for the relaxation peak appearing at temperatures below 900 K, the physical mechanism is related to a vacancy-diffusion-controlled movement of dislocations. In contrast, when the peak appears at temperatures higher than 900 K, the damping is controlled by a mechanism of diffusion in the low-temperature tail of the peak, and in the high-temperature tail of the peak the creation plus diffusion of vacancies at the dislocation line occurs

  12. Relaxed plasmas in external magnetic fields

    International Nuclear Information System (INIS)

    Spies, G.O.; Li, J.

    1991-08-01

    The well-known theory of relaxed plasmas (Taylor states) is extended to external magnetic fields whose field lines intersect the conducting toroidal boundary. Application to an axially symmetric, large-aspect-ratio torus with circular cross section shows that the maximum pinch ratio, and hence the phenomenon of current saturation, is independent of the external field. The relaxed state is explicitly given for an external octupole field. In this case, field reversal is inhibited near parts of the boundary if the octupole generates magnetic x-points within the plasma. (orig.)

  13. Spin transport and relaxation in graphene

    International Nuclear Information System (INIS)

    Han Wei; McCreary, K.M.; Pi, K.; Wang, W.H.; Li Yan; Wen, H.; Chen, J.R.; Kawakami, R.K.

    2012-01-01

    We review our recent work on spin injection, transport and relaxation in graphene. The spin injection and transport in single layer graphene (SLG) were investigated using nonlocal magnetoresistance (MR) measurements. Spin injection was performed using either transparent contacts (Co/SLG) or tunneling contacts (Co/MgO/SLG). With tunneling contacts, the nonlocal MR was increased by a factor of ∼1000 and the spin injection/detection efficiency was greatly enhanced from ∼1% (transparent contacts) to ∼30%. Spin relaxation was investigated on graphene spin valves using nonlocal Hanle measurements. For transparent contacts, the spin lifetime was in the range of 50-100 ps. The effects of surface chemical doping showed that for spin lifetimes in the order of 100 ps, charged impurity scattering (Au) was not the dominant mechanism for spin relaxation. While using tunneling contacts to suppress the contact-induced spin relaxation, we observed the spin lifetimes as long as 771 ps at room temperature, 1.2 ns at 4 K in SLG, and 6.2 ns at 20 K in bilayer graphene (BLG). Furthermore, contrasting spin relaxation behaviors were observed in SLG and BLG. We found that Elliot-Yafet spin relaxation dominated in SLG at low temperatures whereas Dyakonov-Perel spin relaxation dominated in BLG at low temperatures. Gate tunable spin transport was studied using the SLG property of gate tunable conductivity and incorporating different types of contacts (transparent and tunneling contacts). Consistent with theoretical predictions, the nonlocal MR was proportional to the SLG conductivity for transparent contacts and varied inversely with the SLG conductivity for tunneling contacts. Finally, bipolar spin transport in SLG was studied and an electron-hole asymmetry was observed for SLG spin valves with transparent contacts, in which nonlocal MR was roughly independent of DC bias current for electrons, but varied significantly with DC bias current for holes. These results are very important for

  14. Nonlocal and collective relaxation in stellar systems

    Science.gov (United States)

    Weinberg, Martin D.

    1993-01-01

    The modal response of stellar systems to fluctuations at large scales is presently investigated by means of analytic theory and n-body simulation; the stochastic excitation of these modes is shown to increase the relaxation rate even for a system which is moderately far from instability. The n-body simulations, when designed to suppress relaxation at small scales, clearly show the effects of large-scale fluctuations. It is predicted that large-scale fluctuations will be largest for such marginally bound systems as forming star clusters and associations.

  15. NMR relaxation times of natural rubber latex

    International Nuclear Information System (INIS)

    Harun, S.; Aziz, H.; Basir, Z.

    1994-01-01

    NMR relaxation times T sub 1 and T sub 2 of natural rubber latex have been measured at 25 degree C on a pulsed NMR spectrometer. The work focuses on the variation of the relaxation times with the amount of water content from 0% to 50%. The water content was adjusted by centrifuging and removing a certain amount of water from the sample. The data were analysed using a biexponential fitting procedure which yields simultaneously either T sub 1a and T sub 1b or T sub 2a and T sub 2b. The amount of solid was compared with the known amount of dry rubber content

  16. Green--Kubo formula for collisional relaxation

    International Nuclear Information System (INIS)

    Visscher, P.B.

    1988-01-01

    In this paper we generalize the Green--Kubo method (usually used for obtaining formulas for transport coefficients involving conserved densities) to relaxation processes occurring during collisions, such as the transfer of energy from vibrational to translational modes in a molecular fluid. We show that the relaxation rate can be calculated without evaluating time correlation functions over long times, and can in fact be written as a sum over collisions which makes the relation between the Green--Kubo method and approximate independent-collision models much clearer

  17. Exciton-relaxation dynamics in lead halides

    International Nuclear Information System (INIS)

    Iwanaga, Masanobu; Hayashi, Tetsusuke

    2003-01-01

    We survey recent comprehensive studies of exciton relaxation in the crystals of lead halides. The luminescence and electron-spin-resonance studies have revealed that excitons in lead bromide spontaneously dissociate and both electrons and holes get self-trapped individually. Similar relaxation has been also clarified in lead chloride. The electron-hole separation is ascribed to repulsive correlation via acoustic phonons. Besides, on the basis of the temperature profiles of self-trapped states, we discuss the origin of luminescence components which are mainly induced under one-photon excitation into the exciton band in lead fluoride, lead chloride, and lead bromide

  18. Point defect relaxation volumes for copper

    International Nuclear Information System (INIS)

    Miller, K.M.

    1979-11-01

    The methods used for the determination of point defect relaxation volumes are discussed and it is shown that a previous interatomic potential derived for copper is inaccurate and results obtained using it are invalid. A new interatomic potential has been produced for copper and a computer simulation of point and planar defects carried out. A vacancy relaxation volume of -0.33 atomic volumes has been found with interstitial values in the range 1.7 to 2.0 atomic volumes. It is shown that these values in current theories of irradiation induced swelling lead to an anomalously high value for dislocation bias compared with that determined experimentally. (author)

  19. ASM-024, a piperazinium compound, promotes the in vitro relaxation of β2-adrenoreceptor desensitized tracheas.

    Science.gov (United States)

    Israël-Assayag, Evelyne; Beaulieu, Marie-Josée; Cormier, Yvon

    2015-01-01

    Inhaled β2-adrenoreceptor agonists are widely used in asthma and chronic obstructive pulmonary disease (COPD) for bronchoconstriction relief. β2-Adrenoreceptor agonists relax airway smooth muscle cells via cyclic adenosine monophosphate (cAMP) mediated pathways. However, prolonged stimulation induces functional desensitization of the β2-adrenoreceptors (β2-AR), potentially leading to reduced clinical efficacy with chronic or prolonged administration. ASM-024, a small synthetic molecule in clinical stage development, has shown activity at the level of nicotinic receptors and possibly at the muscarinic level and presents anti-inflammatory and bronchodilator properties. Aerosolized ASM-024 reduces airway resistance in mice and promotes in-vitro relaxation of tracheal and bronchial preparations from animal and human tissues. ASM-024 increased in vitro relaxation response to maximally effective concentration of short-acting beta-2 agonists in dog and human bronchi. Although the precise mechanisms by which ASM-024 promotes airway smooth muscle (ASM) relaxation remain unclear, we hypothesized that ASM-024 will attenuate and/or abrogate agonist-induced contraction and remain effective despite β2-AR tachyphylaxis. β2-AR tachyphylaxis was induced with salbutamol, salmeterol and formoterol on guinea pig tracheas. The addition of ASM-024 relaxed concentration-dependently intact or β2-AR desensitized tracheal rings precontracted with methacholine. ASM-024 did not induce any elevation of intracellular cAMP in isolated smooth muscle cells; moreover, blockade of the cAMP pathway with an adenylate cyclase inhibitor had no significant effect on ASM-024-induced guinea pig trachea relaxation. Collectively, these findings show that ASM-024 elicits relaxation of β2-AR desensitized tracheal preparations and suggest that ASM-024 mediates smooth muscle relaxation through a different target and signaling pathway than β2-adrenergic receptor agonists. These findings suggest ASM-024

  20. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    Energy Technology Data Exchange (ETDEWEB)

    Wiesenfeld, J.M.

    1977-12-01

    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 ..mu..s, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N/sub 2/ and O/sub 2/ matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data.

  1. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    International Nuclear Information System (INIS)

    Wiesenfeld, J.M.

    1977-12-01

    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 μs, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N 2 and O 2 matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data

  2. Electron spin relaxation in a transition-metal dichalcogenide quantum dot

    Science.gov (United States)

    Pearce, Alexander J.; Burkard, Guido

    2017-06-01

    We study the relaxation of a single electron spin in a circular quantum dot in a transition-metal dichalcogenide monolayer defined by electrostatic gating. Transition-metal dichalcogenides provide an interesting and promising arena for quantum dot nano-structures due to the combination of a band gap, spin-valley physics and strong spin-orbit coupling. First we will discuss which bound state solutions in different B-field regimes can be used as the basis for qubits states. We find that at low B-fields combined spin-valley Kramers qubits to be suitable, while at large magnetic fields pure spin or valley qubits can be envisioned. Then we present a discussion of the relaxation of a single electron spin mediated by electron-phonon interaction via various different relaxation channels. In the low B-field regime we consider the spin-valley Kramers qubits and include impurity mediated valley mixing which will arise in disordered quantum dots. Rashba spin-orbit admixture mechanisms allow for relaxation by in-plane phonons either via the deformation potential or by piezoelectric coupling, additionally direct spin-phonon mechanisms involving out-of-plane phonons give rise to relaxation. We find that the relaxation rates scale as \\propto B 6 for both in-plane phonons coupling via deformation potential and the piezoelectric effect, while relaxation due to the direct spin-phonon coupling scales independant to B-field to lowest order but depends strongly on device mechanical tension. We will also discuss the relaxation mechanisms for pure spin or valley qubits formed in the large B-field regime.

  3. Relaxation in Thin Polymer Films Mapped across the Film Thickness by Astigmatic Single-Molecule Imaging

    KAUST Repository

    Oba, Tatsuya

    2012-06-19

    We have studied relaxation processes in thin supported films of poly(methyl acrylate) at the temperature corresponding to 13 K above the glass transition by monitoring the reorientation of single perylenediimide molecules doped into the films. The axial position of the dye molecules across the thickness of the film was determined with a resolution of 12 nm by analyzing astigmatic fluorescence images. The average relaxation times of the rotating molecules do not depend on the overall thickness of the film between 20 and 110 nm. The relaxation times also do not show any dependence on the axial position within the films for the film thickness between 70 and 110 nm. In addition to the rotating molecules we observed a fraction of spatially diffusing molecules and completely immobile molecules. These molecules indicate the presence of thin (<5 nm) high-mobility surface layer and low-mobility layer at the interface with the substrate. (Figure presented) © 2012 American Chemical Society.

  4. Transverse magnetic field effects on the relaxation time of the magnetization in Mn12 measured by {sup 55}Mn-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Y.; Watanabe, K.; Kumagai, K.; Borsa, F.; Gatteschi, D

    2003-05-01

    The longitudinal (H{sub Z}) and transverse (H{sub T}) magnetic field dependence of the relaxation time of the magnetization in Mn12 in its S=10 ground state was measured by NMR. The minima in the relaxation time at the fields for level crossing are due to the quantum tunneling of the magnetization. The shortening of the relaxation time under the application of H{sub T} is shown to be due mainly to the reduction of the energy barrier.

  5. Nuclear magnetic relaxation by the dipolar EMOR mechanism: General theory with applications to two-spin systems.

    Science.gov (United States)

    Chang, Zhiwei; Halle, Bertil

    2016-02-28

    In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. We have embarked on a systematic program to develop, from the stochastic Liouville equation, a general and rigorous theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole coupling strengths, and Larmor frequencies. Here, we present a general theoretical framework applicable to spin systems of arbitrary size with symmetric or asymmetric exchange. So far, the dipolar EMOR theory is only available for a two-spin system with symmetric exchange. Asymmetric exchange, when the spin system is fragmented by the exchange, introduces new and unexpected phenomena. Notably, the anisotropic dipole couplings of non-exchanging spins break the axial symmetry in spin Liouville space, thereby opening up new relaxation channels in the locally anisotropic sites, including longitudinal-transverse cross relaxation. Such cross-mode relaxation operates only at low fields; at higher fields it becomes nonsecular, leading to an unusual inverted relaxation dispersion that splits the extreme-narrowing regime into two sub-regimes. The general dipolar EMOR theory is illustrated here by a detailed analysis of the asymmetric two-spin case, for which we present relaxation dispersion profiles over a wide range of conditions as well as analytical results for integral relaxation rates and time-dependent spin modes in the zero-field and motional-narrowing regimes. The general theoretical framework presented here will enable a quantitative analysis of frequency-dependent water-proton longitudinal relaxation in model systems with immobilized macromolecules and, ultimately, will provide a rigorous link between relaxation-based magnetic resonance image contrast and molecular parameters.

  6. Histopathological and morphometric studies on the hooves of dairy and beef cattle in relation to overgrown sole and laminitis.

    Science.gov (United States)

    Singh, S S; Murray, R D; Ward, W R

    1992-10-01

    In dairy cattle, histopathology of the outer hind claws with overgrown sole revealed arteriosclerosis of blood vessels at the ulcer site in the sole. The laminae did not show any hyperplasia of the epidermis and thrombi were not seen in the blood vessels. Partial or complete disappearance of onychogenic substance was observed in the sole as well as in the wall epidermis. In beef animals, typical changes suggestive of chronic laminitis were seen: these included hyperplasia of the epidermis of the laminae, thrombus formation, arteriosclerosis in the corium of the sole, the abaxial wall and the coronary corium. Morphometric analysis quantified measurements of hooves of normal, beef and dairy cattle. It may be concluded that the changes associated with overgrowth of the sole in dairy cattle are localized to the sole without involvement of the laminae and that the term laminitis is not appropriate in the condition seen in dairy cattle.

  7. Probing of brain states in real-time: Introducing the ConSole environment

    Directory of Open Access Journals (Sweden)

    Thomas eHartmann

    2011-03-01

    Full Text Available Recent years have seen huge advancements in the methods available and used in neuroscience employing EEG or MEG. However, the standard approach is to average a large number of trials for experimentally defined conditions in order to reduce intertrial-variability, i.e. treating it as a source of "noise". Yet it is now more and more accepted that trial-to-trial fluctuations bear functional significance, reflecting fluctuations of "brain states" that predispose perception and action. Such effects are often revealed in a pre-stimulus period, when comparing response variability to an invariant stimulus. However such offline analyses are disadvantageous as they are correlational by drawing conclusions in a posthoc-manner and stimulus presentation is random with respect to the feature of interest. A more direct test is to trigger stimulus presentation when the relevant feature is present. The current paper introduces ConSole (CONstance System for OnLine Eeg, a software package capable of analyzing ongoing EEG / MEG in real-time and presenting auditory and visual stimuli via internal routines. Stimulation via external devices (e.g. TMS or third-party software (e.g. Psyscope X is possible by sending TTL-triggers. With ConSole it is thus possible to target the stimulation at specific brain-states. In contrast to many available applications, ConSole is open-source. Its modular design enhances the power of the software as it can be easily adapted to new challenges and writing new experiments is an easy task. ConSole is already pre-equipped with modules performing standard signal processing steps. The software is also independent from the EEG / MEG system, as long as a driver can be written (currently 2 EEG systems are supported. Besides a general introduction, we present benchmark data regarding performance and validity of the calculations used, as well as three example applications of ConSole in different settings. ConSole can be downloaded at: http://console-kn.sf.net.

  8. MR imaging of the stomach and relaxation measurement with intraluminal hyperpolarized 129Xenon gas

    International Nuclear Information System (INIS)

    Yanagawa, Yasuhiro; Kimura, Atsuomi; Fujiwara, Hideaki; Kinoshita, Yoshimasa; Hattori, Mineyuki; Hiraga, Takashi; Iida, Hidehiro

    2001-01-01

    Using laser optical pumping, the nuclear spin polarization of noble gases can be strongly enhanced. The purpose of this study was to make a simple apparatus that can provide hyperpolarized 129 Xe gas, which can then be used in an attempt to obtain magnetic resonance imaging (MRI). We would also like to study the relaxation behavior of hyperpolarized 129 Xe gas through the measurement of the relaxation time. First, we demonstrated that hyperpolarized 129 Xe gas can be applied to magnetic resonance imaging of the stomach, by using a rat as a model. This was performed under a 4.7 T magnet field using the following imaging parameters for the hyperpolarized 129 Xe gas: TR=50 ms, TE=15 ms, FOV=10 x 10 cm 2 , matrix size 64 x 64, THK=2.54 cm. By using these parameters, we were able to obtain a hyperpolarized image of the stomach in rats for the first time. Next, we measured the relaxation times of the hyperpolarized 129 Xe gas enclosed in cavities such as the stomach of rats as well as in phantoms created by glass and gelatin bulbs. The cavity size dependency of the relaxation time was analyzed on the basis of the kinetic theory of gases. This analysis showed a linear relationship between the relaxation rate (1/T 1 ) and a square inverse of the cavity diameter (1/d 2 ). From this relationship, the wall effect on the 129 Xe relaxation can be estimated in the novel parameter t 1 , wall . This shows drastic dependency on the material of the wall, suggesting a potential use of the relaxation experiment as a diagnostic tool for organ surfaces in the future. (author)

  9. Nonmaxwell relaxation in disordered media: Physical mechanisms and fractional relaxation equations

    International Nuclear Information System (INIS)

    Arkhincheev, V.E.

    2004-12-01

    The problem of charge relaxation in disordered systems has been solved. It is shown, that due to the inhomogeneity of the medium the charge relaxation has a non-Maxwell character. The two physical mechanisms of a such behavior have been founded. The first one is connected with the 'fractality' of conducting ways. The second mechanism of nonexponential non-Maxwell behavior is connected with the frequency dispersion of effective conductivity of heterogeneous medium, initially consisting of conducting phases without dispersion. The new generalized relaxation equations in the form of fractional temporal integro-differential equations are deduced. (author)

  10. CUSTOM RELAXATION INDUCED IMPURITY PHOTOCONDUCTIVITY IN THE UNITED AII BVI and AIII BV

    Directory of Open Access Journals (Sweden)

    L. B. Atlukhanova

    2016-01-01

    Full Text Available Two types of non-standard relaxation induced impurity photoconductivity (IIP observed in photoconductors CdS, ZnSe, GaAs and others, depending on the kinetic characteristics of the traps are described. In one case, at the stage of post flashing monotonic decay which is typical for relaxation associated with slow traps (the ratio of the speed of the electron capture to the recombination rate (R << 1, the photo response is experiencing vibrations of low frequency (f =0.03-0.3Hz. Relaxation of the second type characterized by rapid photoelectric traps (R >> 1: measurement alternating signal (f > 20 Hz relaxation curves take the form of curves usual impurity photoconductivity. Electronic processes responsible for relaxation of non-standard IIP are analyzed. For example, fast-centers, which include the characteristic AIIBVI donor Agi0, for the first time in semiconductors experimentally, investigated the dependence of the cross section of electron capture by traps energy released during localization.

  11. PMR spectra and proton magnetic relaxation in uranyl nitrate-hexamethylenetetramine-urea-water gel forming system

    International Nuclear Information System (INIS)

    Vashman, A.A.; Pronin, I.S.; Brylkina, T.V.; Makarov, V.M.

    1979-01-01

    PMR spectra and proton relaxation in the nitrate-hexamethylenetetramine (HMTA)-urea-water gelling system are studied. According to PMR spectra products of HMTA chemical decomposition, which are supposed to be formed in the gelling process, have not been detected. Effect of hydrogen exchange upon PMR spectra of urea and water in the presence of HMTA and uranyl nitrate is studied. Periods of spin-lattice and spin-spin relaxations of water and HMTA protons in gels on the base of uranyl nitrate are found. Data on relaxation permitted to make qualitative conclusions upon the gel structure and HMTA molecule distribution over ''phases''. Nonproducibility of the results of period measurements in gels is the result of nonproducibility of the gel structure in the course of transformation of liquid solution into gel. Temperature dependences of proton relaxation in the gels are impossible yet to interpret on the basis of temperature behaviour of one correlation period, controlling dipole-dipole nuclear magnetic relaxation, and obeying Arrhenius dependence on the temperature

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-03-15

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

  13. Dynamical relaxation in 2HDM models

    Science.gov (United States)

    Lalak, Zygmunt; Markiewicz, Adam

    2018-03-01

    Dynamical relaxation provides an interesting solution to the hierarchy problem in face of the missing signatures of any new physics in recent experiments. Through a dynamical process taking place in the inflationary phase of the Universe it manages to achieve a small electroweak scale without introducing new states observable in current experiments. Appropriate approximation makes it possible to derive an explicit formula for the final vevs in the double-scanning scenario extended to a model with two Higgs doublets (2HDM). Analysis of the relaxation in the 2HDM confirms that in a general case it is impossible to keep vevs of both scalars small, unless fine-tuning is present or additional symmetries are cast upon the Lagrangian. Within the slightly constrained variant of the 2HDM, where odd powers of the fields’ expectation values are not present (which can be easily enforced by requiring that the doublets have different gauge transformations or by imposing a global symmetry) it is shown that the difference between the vevs of two scalars tends to be proportional to the cutoff. The analysis of the relaxation in 2HDM indicates that in a general case the relaxation would be stopped by the first doublet that gains a vev, with the other one remaining vevless with a mass of the order of the cutoff. This happens to conform with the inert doublet model.

  14. Relaxation of coupled nuclear spin systems

    International Nuclear Information System (INIS)

    Koenigsberger, E.

    1985-05-01

    The subject of the present work is the relaxation behaviour of scalarly coupled spin-1/2 systems. In the theoretical part the semiclassical Redfield equations are used. Dipolar (D), Chemical Shift Anisotropy (CSA) and Random Field (RF) interactions are considered as relaxation mechanisms. Cross correlations of dipolar interactions of different nuclei pairs and those between the D and the CSA mechanisms are important. The model of anisotropic molecular rotational relaxation and the extreme narrowing approximation are used to obtain the spectral density functions. The longitudinal relaxation data are analyzed into normal modes following Werbelow and Grant. The time evolution of normal modes is derived for the AX system with D-CSA cross terms. In the experimental part the hypothesis of dimerization in the cinnamic acid and the methyl cinnamate - AMX systems with DD cross terms - is corroborated by T 1 -time measurements and a calculation of the diffusion constants. In pentachlorobenzene - an AX system - taking into account of D-CSA cross terms enables the complete determination of movements anosotropy and the determination of the sign of the indirect coupling constant 1 Jsub(CH). (G.Q.)

  15. Quantization by stochastic relaxation processes and supersymmetry

    International Nuclear Information System (INIS)

    Kirschner, R.

    1984-01-01

    We show the supersymmetry mechanism resposible for the quantization by stochastic relaxation processes and for the effective cancellation of the additional time dimension against the two Grassmann dimensions. We give a non-perturbative proof of the validity of this quantization procedure. (author)

  16. Relaxation dynamics of multilayer triangular Husimi cacti

    Science.gov (United States)

    Galiceanu, Mircea; Jurjiu, Aurel

    2016-09-01

    We focus on the relaxation dynamics of multilayer polymer structures having, as underlying topology, the Husimi cactus. The relaxation dynamics of the multilayer structures is investigated in the framework of generalized Gaussian structures model using both Rouse and Zimm approaches. In the Rouse type-approach, we determine analytically the complete eigenvalues spectrum and based on it we calculate the mechanical relaxation moduli (storage and loss modulus) and the average monomer displacement. First, we monitor these physical quantities for structures with a fixed generation number and we increase the number of layers, such that the linear topology will smoothly come into play. Second, we keep constant the size of the structures, varying simultaneously two parameters: the generation number of the main layer, G, and the number of layers, c. This fact allows us to study in detail the crossover from a pure Husimi cactus behavior to a predominately linear chain behavior. The most interesting situation is found when the two limiting topologies cancel each other. For this case, we encounter in the intermediate frequency/time domain regions of constant slope for different values of the parameter set (G, c) and we show that the number of layers follows an exponential-law of G. In the Zimm-type approach, which includes the hydrodynamic interactions, the quantities that describe the mechanical relaxation dynamics do not show scaling behavior as in the Rouse model, except the limiting case, namely, a very high number of layers and low generation number.

  17. Waveform relaxation methods for implicit differential equations

    NARCIS (Netherlands)

    P.J. van der Houwen; W.A. van der Veen

    1996-01-01

    textabstractWe apply a Runge-Kutta-based waveform relaxation method to initial-value problems for implicit differential equations. In the implementation of such methods, a sequence of nonlinear systems has to be solved iteratively in each step of the integration process. The size of these systems

  18. Collection Development: Relaxation & Meditation, September 1, 2010

    Science.gov (United States)

    Lettus, Dodi

    2010-01-01

    One of the first books to document the relationship between stress and physical and emotional health was "The Relaxation Response" by Herbert Benson, M.D., with Miriam Z. Klipper. Originally published in 1975, the book grew out of Benson's observations as a cardiologist and his research as a fellow at Harvard Medical School. Benson's study of…

  19. Relaxation time in confined disordered systems

    International Nuclear Information System (INIS)

    Chamati, H.; Korutcheva, E.

    2006-05-01

    The dynamic critical behavior of a quenched hypercubic sample of linear size L is considered within the 'random T c ' field theoretical model with purely relaxation dynamic (Model A). The dynamic finite size scaling behavior is established and analyzed when the system is quenched from a homogeneous phase towards its critical temperature. The obtained results are compared to those reported in the literature. (author)

  20. Stretched Exponential relaxation in pure Se glass

    Science.gov (United States)

    Dash, S.; Ravindren, S.; Boolchand, P.

    A universal feature of glasses is the stretched exponential relaxation, f (t) = exp[ - t / τ ] β . The model of diffusion of excitations to randomly distributed traps in a glass by Phillips1 yields the stretched exponent β = d[d +2] where d, the effective dimensionality. We have measured the enthalpy of relaxation ΔHnr (tw) at Tg of Se glass in modulated DSC experiments as glasses age at 300K and find β = 0.43(2) for tw in the 0 relaxation is a narrowing of the glass transition width from 7.1°C to 1.4°C, and the ΔHnr term increasing from 0.21 cal/gm to 0.92 cal/gm. In bulk GexSe100-x glasses as x increases to 20%, the length of the polymeric Sen chains between the Ge-crosslinks decreases to n = 2. and the striking relaxation effects nearly vanish. J.C. Phillips, Rep.Prog.Phys. 59 , 1133 (1996). Supported by NSF Grant DMR 08-53957.