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Sample records for airy stress function

  1. Numerical evaluation of the incomplete airy functions and their application to high frequency scattering and diffraction

    NASA Technical Reports Server (NTRS)

    Constantinides, E. D.; Marhefka, R. J.

    1992-01-01

    The incomplete Airy integrals serve as canonical functions for the uniform ray optical solutions to several high frequency scattering and diffraction problems that involve a class of integrals characterized by two stationary points that are arbitrarily close to one another or to an integration endpoint. Integrals of such analytical properties describe transition region phenomena associated with composite shadow boundaries. An efficient and accurate method for computing the incomplete Airy functions would make the solutions to such problems useful for engineering purposes. Here, a convergent series solution form for the incomplete Airy functions is derived. Asymptotic expansions involving several terms were also developed and serve as large argument approximations. The combination of the series solution form with the asymptotic formulae provides for an efficient and accurate computation of the incomplete Airy functions. Validation of accuracy is accomplished using direct numerical integration data.

  2. On the efficient calculation of the incomplete Airy function with application to edge diffraction

    NASA Astrophysics Data System (ADS)

    Cwik, Tom

    1988-12-01

    When the geometrical theory of diffraction (GTD) and its extensions are used to calculate fields across transition regions or in focal areas, various special functions are necessary to create uniform representations. One such transition function is the incomplete Airy function, which is applicable when two reflection points are arbitrarily close to each other and the endpoint of the domain considered. An efficient calculation of the incomplete Airy function is presented and shown to equal known asymptotic expansions when its argument is away from the critical point. By using these expansions, uniform field expressions are found which are consistent with the GTD and maintain its computational efficiency.

  3. Inpainting using airy diffusion

    NASA Astrophysics Data System (ADS)

    Lorduy Hernandez, Sara

    2015-09-01

    One inpainting procedure based on Airy diffusion is proposed, implemented via Maple and applied to some digital images. Airy diffusion is a partial differential equation with spatial derivatives of third order in contrast with the usual diffusion with spatial derivatives of second order. Airy diffusion generates the Airy semigroup in terms of the Airy functions which can be rewritten in terms of Bessel functions. The Airy diffusion can be used to smooth an image with the corresponding noise elimination via convolution. Also the Airy diffusion can be used to erase objects from an image. We build an algorithm using the Maple package ImageTools and such algorithm is tested using some images. Our results using Airy diffusion are compared with the similar results using standard diffusion. We observe that Airy diffusion generates powerful filters for image processing which could be incorporated in the usual packages for image processing such as ImageJ and Photoshop. Also is interesting to consider the possibility to incorporate the Airy filters as applications for smartphones and smart-glasses.

  4. Constraints on Airy function zeros from quantum-mechanical sum rules

    NASA Astrophysics Data System (ADS)

    Belloni, M.; Robinett, R. W.

    2009-02-01

    We derive new constraints on the zeros of Airy functions by using the so-called quantum bouncer system to evaluate quantum-mechanical sum rules and perform perturbation theory calculations for the Stark effect. Using commutation and completeness relations, we show how to systematically evaluate sums of the form Sp(n) = ∑k≠n1/(ζk - ζn)p, for natural p > 1, where -ζn is the nth zero of Ai(ζ).

  5. Airy Equation for the Topological String Partition Function in a Scaling Limit

    NASA Astrophysics Data System (ADS)

    Alim, Murad; Yau, Shing-Tung; Zhou, Jie

    2016-06-01

    We use the polynomial formulation of the holomorphic anomaly equations governing perturbative topological string theory to derive the free energies in a scaling limit to all orders in perturbation theory for any Calabi-Yau threefold. The partition function in this limit satisfies an Airy differential equation in a rescaled topological string coupling. One of the two solutions of this equation gives the perturbative expansion and the other solution provides geometric hints of the non-perturbative structure of topological string theory. Both solutions can be expanded naturally around strong coupling.

  6. Diffraction by three-dimensional slit-shape curves: decomposition in terms of Airy and Pearcey functions.

    PubMed

    Martinez-Vara, P; Barranco, J Silva; De Los Santos G, S I; Munoz-Lopez, J; Torres-Rodriguez, M A; Xique, R Suarez; Martinez-Niconoff, G

    2015-08-01

    We analyze the diffraction field generated by coherent illumination of a three-dimensional transmittance characterized by a slit-shape curve. Generic features are obtained using the Frenet-Serret equations, which allow a decomposition of the optical field. The analysis is performed by describing the influence of the curvature and torsion on osculating, normal, and rectifying planes. We show that the diffracted field has a decomposition in three optical fields propagating along three optical axes that are mutually perpendicular. The decomposition is in terms of the Pearcey and Airy functions, and the generalized Airy function. Experimental results are shown. PMID:26258341

  7. Acoustic non-diffracting Airy beam

    SciTech Connect

    Lin, Zhou; Guo, Xiasheng Tu, Juan; Ma, Qingyu; Wu, Junru; Zhang, Dong

    2015-03-14

    The acoustic non-diffracting Airy beam as its optical counterpart has unique features of self-bending and self-healing. The complexity of most current designs handicaps its applications. A simple design of an acoustic source capable of generating multi-frequency and broad-band acoustic Airy beam has been theoretically demonstrated by numerical simulations. In the design, a piston transducer is corrugated to induce spatial phase variation for transducing the Airy function. The piston's surface is grooved in a pattern that the width of each groove corresponds to the half wavelength of Airy function. The resulted frequency characteristics and its dependence on the size of the piston source are also discussed. This simple design may promote the wide applications of acoustic Airy beam particularly in the field of medical ultrasound.

  8. Generation of electron Airy beams.

    PubMed

    Voloch-Bloch, Noa; Lereah, Yossi; Lilach, Yigal; Gover, Avraham; Arie, Ady

    2013-02-21

    Within the framework of quantum mechanics, a unique particle wave packet exists in the form of the Airy function. Its counterintuitive properties are revealed as it propagates in time or space: the quantum probability wave packet preserves its shape despite dispersion or diffraction and propagates along a parabolic caustic trajectory, even though no force is applied. This does not contradict Newton's laws of motion, because the wave packet centroid propagates along a straight line. Nearly 30 years later, this wave packet, known as an accelerating Airy beam, was realized in the optical domain; later it was generalized to an orthogonal and complete family of beams that propagate along parabolic trajectories, as well as to beams that propagate along arbitrary convex trajectories. Here we report the experimental generation and observation of the Airy beams of free electrons. These electron Airy beams were generated by diffraction of electrons through a nanoscale hologram, which imprinted on the electrons' wavefunction a cubic phase modulation in the transverse plane. The highest-intensity lobes of the generated beams indeed followed parabolic trajectories. We directly observed a non-spreading electron wavefunction that self-heals, restoring its original shape after passing an obstacle. This holographic generation of electron Airy beams opens up new avenues for steering electronic wave packets like their photonic counterparts, because the wave packets can be imprinted with arbitrary shapes or trajectories.

  9. Full characterization of Airy beams under physical principles

    NASA Astrophysics Data System (ADS)

    Rogel-Salazar, J.; Jiménez-Romero, H. A.; Chávez-Cerda, S.

    2014-02-01

    The propagation characteristics of Airy beams is investigated and fully described under the traveling-wave approach analogous to that used for nondiffracting Bessel beams. This is possible when noticing that Airy functions are, in fact, Bessel functions of fractional order 1/3. We show how physical principles impose restrictions such that the nondiffracting Airy beams cannot be of infinite extent as has been argued and introduce quantitative expressions for the maximum transverse and longitudinal extent of Airy beams. We show that under the appropriate physical conditions it is possible to obtain higher-order Airy beams.

  10. Stationary nonlinear Airy beams

    SciTech Connect

    Lotti, A.; Faccio, D.; Couairon, A.; Papazoglou, D. G.; Panagiotopoulos, P.; Tzortzakis, S.; Abdollahpour, D.

    2011-08-15

    We demonstrate the existence of an additional class of stationary accelerating Airy wave forms that exist in the presence of third-order (Kerr) nonlinearity and nonlinear losses. Numerical simulations and experiments, in agreement with the analytical model, highlight how these stationary solutions sustain the nonlinear evolution of Airy beams. The generic nature of the Airy solution allows extension of these results to other settings, and a variety of applications are suggested.

  11. Creating Airy beams employing a transmissive spatial light modulator

    NASA Astrophysics Data System (ADS)

    Latychevskaia, Tatiana; Schachtler, Daniel; Fink, Hans-Werner

    2016-08-01

    We present a detailed study of two novel methods for shaping the light optical wavefront by employing a transmissive spatial light modulator (SLM). Conventionally, optical Airy beams are created by employing SLMs in the so-called all phase mode. In the first method, a numerically simulated lens phase distribution is loaded directly onto the SLM, together with the cubic phase distribution. An Airy beam is generated at the focal plane of the numerical lens. We provide for the first time a quantitative properties of the formed Airy beam. We derive the formula for deflection of the intensity maximum of the so formed Airy beam, which is different to the quadratic deflection typical of Airy beams. We cross-validate the derived formula by both simulations and experiment. The second method is based on the fact that a system consisting of a transmissive SLM sandwiched between two polarisers can create a transmission function with negative values. This observation alone has the potential for various other wavefront modulations where the transmission function requires negative values. As an example for this method, we demonstrate that a wavefront can be modulated by passing the SLM system with transmission function with negative values by loading an Airy function distribution directly onto SLM. Since the Airy function is a real-valued function but also with negative values, an Airy beam can be generated by direct transfer of the Airy function distribution onto such an SLM system. In this way, an Airy beam is generated immediately behind the SLM. As both new methods do not employ a physical lens, the two setups are more compact than conventional setups for creating Airy beams. We compare the performance of the two novel methods and the properties of the created Airy beams.

  12. Creating Airy beams employing a transmissive spatial light modulator.

    PubMed

    Latychevskaia, Tatiana; Schachtler, Daniel; Fink, Hans-Werner

    2016-08-01

    We present a detailed study of two novel methods for shaping the light optical wavefront by employing a transmissive spatial light modulator (SLM). Conventionally, optical Airy beams are created by employing SLMs in the so-called all-phase mode. In the first method, a numerically simulated lens phase distribution is loaded directly onto the SLM, together with the cubic phase distribution. An Airy beam is generated at the focal plane of the numerical lens. We provide for the first time, to the best of our knowledge, quantitative properties of the formed Airy beam. We derive the formula for deflection of the intensity maximum of the so-formed Airy beam, which is different from the quadratic deflection typical of Airy beams. We cross-validate the derived formula by both simulations and experiment. The second method is based on the fact that a system consisting of a transmissive SLM sandwiched between two polarizers can create a transmission function with negative values. This observation alone has the potential for various other wavefront modulations where the transmission function requires negative values. As an example for this method, we demonstrate that a wavefront can be modulated by passing the SLM system with transmission function with negative values by loading an Airy function distribution directly onto the SLM. Since the Airy function is a real-valued function but also with negative values, an Airy beam can be generated by direct transfer of the Airy function distribution onto such an SLM system. In this way, an Airy beam is generated immediately behind the SLM. As both new methods do not employ a physical lens, the two setups are more compact than conventional setups for creating Airy beams. We compare the performance of the two novel methods and the properties of the created Airy beams. PMID:27505393

  13. Nonclassicality of vortex Airy beams in the Wigner representation

    SciTech Connect

    Chen Ruipin; Ooi, C. H. Raymond

    2011-10-15

    The Wigner distribution function (WDF) of a vortex Airy beam is calculated analytically. The WDF provides intuitive pictures of the intriguing features of vorticity in phase space. The nonclassical property of the vortex Airy beam and the Airy beam is analyzed through the negative parts of the WDF. The study shows that destructive interference of certain classical waves can mimic nonclassical lights such as those due to quantum effects.

  14. Propagation Dynamics of Airy Water-Wave Pulses.

    PubMed

    Fu, Shenhe; Tsur, Yuval; Zhou, Jianying; Shemer, Lev; Arie, Ady

    2015-07-17

    We observe the propagation dynamics of surface gravity water waves, having an Airy function envelope, in both the linear and the nonlinear regimes. In the linear regime, the shape of the envelope is preserved while propagating in an 18-m water tank, despite the inherent dispersion of the wave packet. The Airy wave function can propagate at a velocity that is slower (or faster if the Airy envelope is inverted) than the group velocity. Furthermore, the introduction of the Airy wave packet as surface water waves enables the observation of its position-dependent chirp and cubic-phase offset, predicted more than 35 years ago, for the first time. When increasing the envelope of the input Airy pulse, nonlinear effects become dominant, and are manifested by the generation of water-wave solitons. PMID:26230797

  15. Ultrabroadband Airy light bullets

    NASA Astrophysics Data System (ADS)

    Piksarv, Peeter; Valdmann, Andreas; Valtna-Lukner, Heli; Saari, Peeter

    2014-04-01

    We present the measurements of the spatiotemporal impulse responses of two optical systems for launching ultrashort Airy pulses, incl. ultrabroadband nonspreading Airy beams whose main lobe size remains invariantly small over propagation. First, a spatial light modulator and, second, a custom refractive element with continuous surface profile were used to impose the required cubic phase on the input field. White-light spectral interferometry setup based on the SEA TADPOLE technique was applied for full spatio-temporal characterization of the impulse response with ultrahigh temporal resolution approaching a single cycle of the light wave. The results were compared to the theoretical model.

  16. Ultrabroadband Airy light bullets

    NASA Astrophysics Data System (ADS)

    Piksarv, P.; Valdmann, A.; Valtna-Lukner, H.; Saari, P.

    2014-08-01

    We present the measurements of the spatiotemporal impulse responses of two optical systems for launching ultrashort Airy pulses, including ultrabroadband nonspreading Airy beams whose main lobe size remains invariantly small over propagation. First, a spatial light modulator and, second, a custom refractive element with continuous surface profile were used to impose the required cubic phase on the input field. A white-light spectral interferometry setup based on the SEA TADPOLE technique was applied for full spatio-temporal characterization of the impulse response with ultrahigh temporal resolution approaching a single cycle of the light wave. The results were compared to the theoretical model.

  17. Airy structure in 16O+14C nuclear rainbow scattering

    NASA Astrophysics Data System (ADS)

    Ohkubo, S.; Hirabayashi, Y.

    2015-08-01

    The Airy structure in 16 O +14 C rainbow scattering is studied with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for 16 O by using a density-dependent nucleon-nucleon force. The experimental angular distributions at EL=132 , 281, and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum around θ =76∘ in the angular distribution at EL=132 MeV is assigned as the second-order Airy minimum A 2 in contrast to the recent literature which assigns it as the third order A 3 . The Airy minima in the 90∘ excitation function is investigated in comparison with well-known 16 O +16 O and 12 C +12 C systems. Evolution of the Airy structure into the molecular resonances with the 16 O +14 C cluster structure in the low-energy region around Ec .m .=30 MeV is discussed. It is predicted theoretically for the first time for a non-4 N 16O +14 C system that Airy elephants in the 90∘ excitation function are present.

  18. Accelerating Airy beams in the presence of inhomogeneities

    NASA Astrophysics Data System (ADS)

    Besieris, Ioannis M.; Shaarawi, Amr M.; Zamboni-Rached, Michel

    2016-06-01

    Studies have already been made of accelerating Airy beams in the presence of deterministic inhomogeneities, illustrating, in particular, that the inherent self-healing properties of such beams are preserved. The cases of a range-dependent linear transverse potential and a converging GRIN structure (harmonic oscillator) have been examined thoroughly. Examples will be given in this article of novel accelerating Airy beams in the presence of five other types of potential functions. Three of the resulting exact analytical solutions have a common salient characteristic property: they are constructed using the free-space accelerating Airy beam solution as a seed.

  19. Voigt Airy surface magneto plasmons.

    PubMed

    Hu, Bin; Wang, Qi Jie; Zhang, Ying

    2012-09-10

    We present a basic theory on Airy surface magneto plasmons (SMPs) at the interface between a dielectric layer and a metal layer (or a doped semiconductor layer) under an external static magnetic field in the Voigt configuration. It is shown that, in the paraxial approximation, the Airy SMPs can propagate along the surface without violating the nondiffracting characteristics, while the ballistic trajectory of the Airy SMPs can be tuned by the applied magnetic field. In addition, the self-deflection-tuning property of the Airy SMPs depends on the direction of the external magnetic field applied, owing to the nonreciprocal effect. PMID:23037243

  20. Controllable Airy-like beams induced by tunable phase patterns

    NASA Astrophysics Data System (ADS)

    Li, D.; Qian, Y.

    2016-01-01

    We propose and experimentally observe a novel family of Airy-like beams. First, we theoretically investigate the physical generation of our proposed controllable Airy-like beams by introducing a rotation angle factor into the phase function, which can regulate and flexibly control the beam wavefront. Meanwhile we can also readily control the main lobes of these beams to follow appointed parabolic trajectories using the rotation angle factor. We also demonstrate that the controllable Airy-like beams lack the properties of being diffraction-free and self-healing. The experiments are performed and the results are in accord with the theoretical simulations. We believe that the intriguing characteristics of our proposed Airy-like beams could provide more degrees of freedom, and are likely to give rise to new applications and lend versatility to the emerging field.

  1. Bohmian trajectories of Airy packets

    NASA Astrophysics Data System (ADS)

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-01

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space-time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject's theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  2. Bohmian trajectories of Airy packets

    SciTech Connect

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-15

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space–time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject’s theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  3. Airy beam optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Aadhi, A.; Chaitanya, N. Apurv; Jabir, M. V.; Vaity, Pravin; Singh, R. P.; Samanta, G. K.

    2016-05-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51–1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).

  4. Airy beam optical parametric oscillator.

    PubMed

    Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K

    2016-01-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond). PMID:27143582

  5. Airy beam optical parametric oscillator.

    PubMed

    Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K

    2016-05-04

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).

  6. Airy beam optical parametric oscillator

    PubMed Central

    Aadhi, A.; Chaitanya, N. Apurv; Jabir, M. V.; Vaity, Pravin; Singh, R. P.; Samanta, G. K.

    2016-01-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51–1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond). PMID:27143582

  7. Accurate Thermal Stresses for Beams: Normal Stress

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Pilkey, Walter D.

    2003-01-01

    Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

  8. Accurate Thermal Stresses for Beams: Normal Stress

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Pilkey, Walter D.

    2002-01-01

    Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

  9. Rainbows: Mie computations and the Airy approximation.

    PubMed

    Wang, R T; van de Hulst, H C

    1991-01-01

    Efficient and accurate computation of the scattered intensity pattern by the Mie formulas is now feasible for size parameters up to x = 50,000 at least, which in visual light means spherical drops with diameters up to 6 mm. We present a method for evaluating the Mie coefficients from the ratios between Riccati-Bessel and Neumann functions of successive order. We probe the applicability of the Airy approximation, which we generalize to rainbows of arbitrary p (number of internal reflections = p - 1), by comparing the Mie and Airy intensity patterns. Millimeter size water drops show a match in all details, including the position and intensity of the supernumerary maxima and the polarization. A fairly good match is still seen for drops of 0.1 mm. A small spread in sizes helps to smooth out irrelevant detail. The dark band between the rainbows is used to test more subtle features. We conclude that this band contains not only externally reflected light (p = 0) but also a sizable contribution f rom the p = 6 and p = 7 rainbows, which shift rapidly with wavelength. The higher the refractive index, the closer both theories agree on the first primary rainbow (p = 2) peak for drop diameters as small as 0.02 mm. This may be useful in supporting experimental work. PMID:20581954

  10. Continuum Statistics of the Airy2 Process

    NASA Astrophysics Data System (ADS)

    Corwin, Ivan; Quastel, Jeremy; Remenik, Daniel

    2013-01-01

    We develop an exact determinantal formula for the probability that the Airy_2 process is bounded by a function g on a finite interval. As an application, we provide a direct proof that {sup({A}2(x)-x^2)} is distributed as a GOE random variable. Both the continuum formula and the GOE result have applications in the study of the end point of an unconstrained directed polymer in a disordered environment. We explain Johansson's (Commun. Math. Phys. 242(1-2):277-329, 2003) observation that the GOE result follows from this polymer interpretation and exact results within that field. In a companion paper (Moreno Flores et al. in Commun. Math. Phys. 2012) these continuum statistics are used to compute the distribution of the endpoint of directed polymers.

  11. Multi-focus of modulated polarized Airy beam

    NASA Astrophysics Data System (ADS)

    Zhao, Hongyang; Lin, Jie; Tan, Jiubin; Jin, Peng

    2016-07-01

    The focusing performance of a modulated polarized Airy beam is explored by using the Richards and Wolf vectorial diffraction model in a high numerical aperture system. The multiple foca appeared on the focal plane or along the optical axis when a complex amplitude modulating function was introduced. Two focusing spots with long-focal-depth were additionally observed due to the Airy beam and complex amplitude modulation. The distance between the focuses were changed from 1.15λ to 3.56λ with FWHM of 0.9λ for one-dimensional linear polarized incident beam and from 1.15λ to 3.64λ for two-dimensional beam. The multiple focusing spots are expected to apply in the field of optical trapping and particle acceleration.

  12. Spatiotemporal dynamics of counterpropagating Airy beams

    NASA Astrophysics Data System (ADS)

    Wiersma, Noémi; Marsal, Nicolas; Sciamanna, Marc; Wolfersberger, Delphine

    2015-08-01

    We analyse theoretically the spatiotemporal dynamics of two incoherent counterpropagating Airy beams interacting in a photorefractive crystal under focusing conditions. For a large enough nonlinearity strength the interaction between the two Airy beams leads to light-induced waveguiding. The stability of the waveguide is determined by the crystal length, the nonlinearity strength and the beam’s intensities and is improved when comparing to the situation using Gaussian beams. We further identify the threshold above which the waveguide is no longer static but evolves dynamically either time-periodically or even chaotically. Above the stability threshold, each Airy-soliton moves erratically between privileged output positions that correspond to the spatial positions of the lobes of the counterpropagating Airy beam. These results suggest new ways of creating dynamically varying waveguides, optical logic gates and chaos-based computing.

  13. Spatiotemporal dynamics of counterpropagating Airy beams

    PubMed Central

    Wiersma, Noémi; Marsal, Nicolas; Sciamanna, Marc; Wolfersberger, Delphine

    2015-01-01

    We analyse theoretically the spatiotemporal dynamics of two incoherent counterpropagating Airy beams interacting in a photorefractive crystal under focusing conditions. For a large enough nonlinearity strength the interaction between the two Airy beams leads to light-induced waveguiding. The stability of the waveguide is determined by the crystal length, the nonlinearity strength and the beam’s intensities and is improved when comparing to the situation using Gaussian beams. We further identify the threshold above which the waveguide is no longer static but evolves dynamically either time-periodically or even chaotically. Above the stability threshold, each Airy-soliton moves erratically between privileged output positions that correspond to the spatial positions of the lobes of the counterpropagating Airy beam. These results suggest new ways of creating dynamically varying waveguides, optical logic gates and chaos-based computing. PMID:26315530

  14. Ultrafast Airy beam optical parametric oscillator.

    PubMed

    Apurv Chaitanya, N; Kumar, S Chaitanya; Aadhi, A; Samanta, G K; Ebrahim-Zadeh, M

    2016-01-01

    We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm.

  15. Ultrafast Airy beam optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Apurv Chaitanya, N.; Kumar, S. Chaitanya; Aadhi, A.; Samanta, G. K.; Ebrahim-Zadeh, M.

    2016-08-01

    We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm.

  16. Ultrafast Airy beam optical parametric oscillator

    PubMed Central

    Apurv Chaitanya, N.; Kumar, S. Chaitanya; Aadhi, A.; Samanta, G. K.; Ebrahim-Zadeh, M.

    2016-01-01

    We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm. PMID:27476910

  17. Temporal Airy pulses control cell poration

    NASA Astrophysics Data System (ADS)

    Courvoisier, S.; Götte, N.; Zielinski, B.; Winkler, T.; Sarpe, C.; Senftleben, A.; Bonacina, L.; Wolf, J. P.; Baumert, T.

    2016-07-01

    We show that spectral phase shaping of fs-laser pulses can be used to optimize laser-cell membrane interactions in water environment. The energy and peak intensity thresholds required for cell poration with single pulse in the nJ range can be significantly reduced (25% reduction in energy and 88% reduction in peak intensity) by using temporal Airy pulses, controlled by positive third order dispersion, as compared to bandwidth limited pulses. Temporal Airy pulses are also effective to control the morphology of the induced pores, with prospective applications from cellular to tissue opto-surgery and transfection.

  18. Bose-Einstein condensation of {alpha} particles and Airy structure in nuclear rainbow scattering

    SciTech Connect

    Ohkubo, S.; Hirabayashi, Y.

    2004-10-01

    It is shown that the dilute density distribution of {alpha} particles in nuclei can be observed in the Airy structure in nuclear rainbow scattering. We have analyzed {alpha}+{sup 12}C rainbow scattering to the 0{sub 2}{sup +} (7.65 MeV) state of {sup 12}C in a coupled-channel method with the precise wave functions for {sup 12}C. It is found that the enhanced Airy oscillations in the experimental angular distributions for the 0{sub 2}{sup +} state is caused by the dilute density distribution of this state in agreement for the idea of Bose-Einstein condensation of the three alpha particles.

  19. Airy, Sir George Biddell (1801-92)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    A brilliant Cambridge mathematician (Senior Wrangler 1823, i.e. leader of the graduating mathematics class), Airy became the seventh Astronomer Royal in 1835 after a brief period as Lucasian Professor at Cambridge. His output was prodigious, and he published nearly 400 scientific papers and 150 reports on various scientific issues, such as the gauge of railways, spectacles to correct astigmatism,...

  20. Airy acoustical-sheet spinner tweezers

    NASA Astrophysics Data System (ADS)

    Mitri, F. G.

    2016-09-01

    The Airy acoustical beam exhibits parabolic propagation and spatial acceleration, meaning that the propagation bending angle continuously increases before the beam trajectory reaches a critical angle where it decays after a propagation distance, without applying any external bending force. As such, it is of particular importance to investigate its properties from the standpoint of acoustical radiation force, spin torque, and particle dynamics theories, in the development of novel particle sorting techniques and acoustically mediated clearing systems. This work investigates these effects on a two-dimensional (2D) circular absorptive structure placed in the field of a nonparaxial Airy "acoustical-sheet" (i.e., finite beam in 2D), for potential applications in surface acoustic waves and acousto-fluidics. Based on the characteristics of the acoustic field, the beam is capable of manipulating the circular cylindrical fluid cross-section and guides it along a transverse or parabolic trajectory. This feature of Airy acoustical beams could lead to a unique characteristic in single-beam acoustical tweezers related to acoustical sieving, filtering, and removal of particles and cells from a section of a small channel. The analysis developed here is based on the description of the nonparaxial Airy beam using the angular spectrum decomposition of plane waves in close association with the partial-wave series expansion method in cylindrical coordinates. The numerical results demonstrate the ability of the nonparaxial Airy acoustical-sheet beam to pull, propel, or accelerate a particle along a parabolic trajectory, in addition to particle confinement in the transverse direction of wave propagation. Negative or positive radiation force and spin torque causing rotation in the clockwise or the anticlockwise direction can occur depending on the nondimensional parameter ka (where k is the wavenumber and a is the radius) and the location of the cylinder in the beam. Applications in

  1. Norm Estimations of the Modified Teodorescu Transform with Application to a Multidimensional Equation of Airy Type

    SciTech Connect

    Schlichting, A.; Sproessig, W.

    2008-09-01

    We study versions of a generalized Teodorescu transform. In the 2-dimensional case we can describe the asymptotic behaviour by the help of modified Bessel functions. In 3-dimensional case we only have an upper estimate. Such estimates are necessary to prove the convergence of a semi-discretization method for a higher-dimensional analogue of an equation of Airy's type.

  2. Adding stress plot function to NASTRAN

    NASA Technical Reports Server (NTRS)

    Katoh, S.

    1978-01-01

    Stress plot function was developed and added to the NASTRAN level 15.5. Computed stress distribution can be displayed by this function, with vectors showing the principal stresses of the finite elements over the specified portions of the structure. NASTRAN is reviewed in the aspect of plotting capabilities. Stress tensor field is examined in preparation of stress display. Then the stress plot function as added to the NASTRAN is described. A sample plotout by this function is shown.

  3. Airy beam self-focusing in a photorefractive medium

    NASA Astrophysics Data System (ADS)

    Wiersma, Noémi; Marsal, Nicolas; Sciamanna, Marc; Wolfersberger, Delphine

    2016-10-01

    The unique bending and shape-preserving properties of optical Airy beams offer a large range of applications in for example beam routing, optical waveguiding, particle manipulation and plasmonics. In these applications and others, the Airy beam may experience nonlinear light-matter interactions which in turn modify the Airy beam properties and propagation. A well-known example is light self-focusing that leads to the formation of spatial soliton. Here, we unveil experimentally the self-focusing properties of a 1D-Airy beam in a photorefractive crystal under focusing conditions. The transient evolution involves both self-bending and acceleration of the initially launched Airy beam due to the onset of an off-shooting soliton and the resulting nonlocal refractive index perturbation. Both the transient and stationary self-focusing properties can be tuned by varying the bias electric field, the injected Airy beam power and the background illumination.

  4. Airy beam self-focusing in a photorefractive medium

    PubMed Central

    Wiersma, Noémi; Marsal, Nicolas; Sciamanna, Marc; Wolfersberger, Delphine

    2016-01-01

    The unique bending and shape-preserving properties of optical Airy beams offer a large range of applications in for example beam routing, optical waveguiding, particle manipulation and plasmonics. In these applications and others, the Airy beam may experience nonlinear light-matter interactions which in turn modify the Airy beam properties and propagation. A well-known example is light self-focusing that leads to the formation of spatial soliton. Here, we unveil experimentally the self-focusing properties of a 1D-Airy beam in a photorefractive crystal under focusing conditions. The transient evolution involves both self-bending and acceleration of the initially launched Airy beam due to the onset of an off-shooting soliton and the resulting nonlocal refractive index perturbation. Both the transient and stationary self-focusing properties can be tuned by varying the bias electric field, the injected Airy beam power and the background illumination. PMID:27731356

  5. Propagation of Bessel and Airy beams through atmospheric turbulence.

    PubMed

    Nelson, W; Palastro, J P; Davis, C C; Sprangle, P

    2014-03-01

    We investigate, through simulation, the modifications to Bessel and Airy beams during propagation through atmospheric turbulence. We find that atmospheric turbulence disrupts the quasi-non-diffracting nature of Bessel and Airy beams when the transverse coherence length (Fried parameter) nears the initial aperture diameter or diagonal, respectively. The turbulence-induced transverse phase distortion limits the effectiveness of Bessel and Airy beams for applications requiring propagation over long distances in the turbulent atmosphere.

  6. Accelerating Airy-Gauss-Kummer localized wave packets

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Ping; Belić, Milivoj; Zhang, Yiqi; Huang, Tingwen

    2014-01-01

    A general approach to generating three-dimensional nondiffracting spatiotemporal solutions of the linear Schrödinger equation with an Airy-beam time-dependence is reported. A class of accelerating optical pulses with the structure of Airy-Gauss-Kummer vortex beams is obtained. Our results demonstrate that the optical field contributions to the Airy-Gauss-Kummer accelerating optical wave packets of the cylindrical symmetry can be characterized by the radial and angular mode numbers.

  7. Autobiography of Sir George Biddell Airy

    NASA Astrophysics Data System (ADS)

    Airy, George Biddell; Airy, Wilfred

    2010-06-01

    Preface; 1. Personal sketch of George Biddell Airy; 2. From his birth to his taking his B.A. degree; 3. At Trinity College, Cambridge; 4. At Cambridge Observatory; 5. At Greenwich Observatory, 1836-1846; 6. At Greenwich Observatory, 1846-1856; 7. At Greenwich Observatory, 1856-1866; 8. At Greenwich Observatory, 1866-1876; 9. At Greenwich Observatory to his resignation in 1881; 10. At the White House, Greewich, to his death; Appendix: List of printed papers; Index.

  8. Stress, fighting and neuroendocrine function.

    NASA Technical Reports Server (NTRS)

    Conner, R. L.; Levine, S.; Vernikos-Danellis, J.

    1971-01-01

    Plasma concentrations of pituitary adrenocorticotrophic hormone (ACTH) and adrenocortical steroids in rats after testing in the shock-induced fighting paradigm were examined. The investigations provide data consistent with the view that psychological aspects of the stressful situation are important in determining the effects of shock on physiological function. The data indicate that the pituitary-adrenal response can be attenuated by the expression of an organized pattern of behavior.

  9. Spinning of a submicron sphere by Airy beams.

    PubMed

    Kim, Kyoung-Youm; Kim, Saehwa

    2016-01-01

    We show that by employing two incoherent counter-propagating Airy beams, we can manipulate a submicron sphere to spin around a transverse axis. We can control not only the spinning speed, but also the direction of the spinning axis by changing the polarization directions of Airy beams.

  10. Accelerated and Airy-Bloch oscillations

    NASA Astrophysics Data System (ADS)

    Longhi, Stefano

    2016-09-01

    A quantum particle subjected to a constant force undergoes an accelerated motion following a parabolic path, which differs from the classical motion just because of wave packet spreading (quantum diffusion). However, when a periodic potential is added (such as in a crystal) the particle undergoes Bragg scattering and an oscillatory (rather than accelerated) motion is found, corresponding to the famous Bloch oscillations (BOs). Here, we introduce an exactly-solvable quantum Hamiltonian model, corresponding to a generalized Wannier-Stark Hamiltonian Ĥ, in which a quantum particle shows an intermediate dynamical behavior, namely an oscillatory motion superimposed to an accelerated one. Such a novel dynamical behavior is referred to as accelerated BOs. Analytical expressions of the spectrum, improper eigenfunctions and propagator of the generalized Wannier-Stark Hamiltonian Ĥ are derived. Finally, it is shown that acceleration and quantum diffusion in the generalized Wannier-Stark Hamiltonian are prevented for Airy wave packets, which undergo a periodic breathing dynamics that can be referred to as Airy-Bloch oscillations.

  11. Fabry-Pérot resonator: spectral line shapes, generic and related Airy distributions, linewidths, finesses, and performance at low or frequency-dependent reflectivity.

    PubMed

    Ismail, Nur; Kores, Cristine Calil; Geskus, Dimitri; Pollnau, Markus

    2016-07-25

    We systematically characterize the Fabry-Pérot resonator. We derive the generic Airy distribution of a Fabry-Pérot resonator, which equals the internal resonance enhancement factor, and show that all related Airy distributions are obtained by simple scaling factors. We analyze the textbook approaches to the Fabry-Pérot resonator and point out various misconceptions. We verify that the sum of the mode profiles of all longitudinal modes is the fundamental physical function that characterizes the Fabry-Pérot resonator and generates the Airy distribution. Consequently, the resonator losses are quantified by the linewidths of the underlying Lorentzian lines and not by the measured Airy linewidth. Therefore, we introduce the Lorentzian finesse which provides the spectral resolution of the Lorentzian lines, whereas the usually considered Airy finesse only quantifies the performance of the Fabry-Pérot resonator as a scanning spectrometer. We also point out that the concepts of linewidth and finesse of the Airy distribution of a Fabry-Pérot resonator break down at low reflectivity. Furthermore, we show that a Fabry-Pérot resonator has no cut-off resonance wavelength. Finally, we investigate the influence of frequency-dependent mirror reflectivities, allowing for the direct calculation of its deformed mode profiles.

  12. Methodology of contact stress analysis of gearwheel by means of experimental photoelasticity.

    PubMed

    Frankovský, Peter; Ostertag, Oskar; Trebuňa, František; Ostertagová, Eva; Kelemen, Michal

    2016-06-20

    The subject of this paper is the analysis of contact stresses that occur between the teeth of a gear. The analysis was carried out by means of reflection photoelasticity, which is an experimental method rarely used in this field. Contact stresses assessed in the experiment are compared with values assessed through an analytical calculation while using the Airy stress function or Hertzian relations. PMID:27409110

  13. AiryÕs Greenwich Staff

    NASA Astrophysics Data System (ADS)

    Chapman, A.

    2012-01-01

    One major research development in the history of astronomy, pioneered in particular by the SHA, is a shift from the concern with what the ÔgiantsÕ, such as Galileo or Newton, achieved to an examination of the wider spectrum of astronomical personnel. And one rich field of inquiry here is that body of men, and later of women, who earned their livings as assistant astronomers. It is, in fact, an abundantly documented area, including figures employed in Grand Amateur, university, and civic observatories, though without doubt the richest and longest-running body of data pertaining to what might be called the ÔAstronomersÕ GentlemenÕ comes from the archives of the Royal Observatory, Greenwich, especially for the years 1835 to 1881, when Sir George Biddell Airy was Astronomer Royal.

  14. Interpolation between Airy and Poisson statistics for unitary chiral non-Hermitian random matrix ensembles

    SciTech Connect

    Akemann, G.; Bender, M.

    2010-10-15

    We consider a family of chiral non-Hermitian Gaussian random matrices in the unitarily invariant symmetry class. The eigenvalue distribution in this model is expressed in terms of Laguerre polynomials in the complex plane. These are orthogonal with respect to a non-Gaussian weight including a modified Bessel function of the second kind, and we give an elementary proof for this. In the large n limit, the eigenvalue statistics at the spectral edge close to the real axis are described by the same family of kernels interpolating between Airy and Poisson that was recently found by one of the authors for the elliptic Ginibre ensemble. We conclude that this scaling limit is universal, appearing for two different non-Hermitian random matrix ensembles with unitary symmetry. As a second result we give an equivalent form for the interpolating Airy kernel in terms of a single real integral, similar to representations for the asymptotic kernel in the bulk and at the hard edge of the spectrum. This makes its structure as a one-parameter deformation of the Airy kernel more transparent.

  15. Generation and propagation dynamics of Airy beam with the tunable tail

    NASA Astrophysics Data System (ADS)

    Liu, Huilong; Lü, Yanfei; Xia, Jing; Pu, Xiaoyun; Zhang, Li

    2016-05-01

    We introduce a new kind of Airy beam called Airy beam with the tunable tail, which can be generated from the elliptical flat-topped Gaussian beam. The analytical formula of Airy beam with the tunable tail is derived. Airy beam with the single tail can be obtained by adjusting the ration of the beam width of elliptical flat-topped Gaussian beam. The tail length of Airy beam can be controlled by the order N of incident beam. The normalized intensity distributions of Airy beam with the tunable tail propagating in free space are studied, and the propagation dynamics of Airy beam with the single tail are investigated. Compared with the Airy beam generated from the fundamental Gaussian beam or the flat-topped Gaussian beam, some interesting and useful information has been found.

  16. Vessel extraction using the Buckmaster-Airy filter

    NASA Astrophysics Data System (ADS)

    Sanchez, Valentina

    2016-05-01

    A new and powerful technique for vessel extraction from biomedical images using the so called Buckmaster- Airy Filter is designed, prototyped and tested. The design, the prototyping and the testing were performed using computer algebra software, specifically the Maple package ImageTools. Some preliminary experiments were performed ant the results were excellent. Our new technique is based on partial differential equations.. Specifically two dimensional Airy diffusion equation and the two dimensional Buckmaster equation were used for designing the new Buckmaster-Airy Filter. Such new filter is able to enhance the quality of an image, producing simultaneously noise elimination, but without altering the edges of the image. The new Bukmaster-Airy filter is applied to the target image via discrete convolution. The results of some experiments of vessel extraction will be presented; and some lines for future research such as the possible implementation of the Buckmaster-Airy Filter as a new plugging for the program ImageJ, will be proposed.

  17. Propagation of an Airy beam through the atmosphere.

    PubMed

    Ji, Xiaoling; Eyyuboğlu, Halil T; Ji, Guangming; Jia, Xinhong

    2013-01-28

    In this paper, the effect of thermal blooming of an Airy beam propagating through the atmosphere is examined, and the effect of atmospheric turbulence is not considered. The changes of the intensity distribution, the centroid position and the mean-squared beam width of an Airy beam propagating through the atmosphere are studied by using the four-dimensional (4D) computer code of the time-dependent propagation of Airy beams through the atmosphere. It is shown that an Airy beam can't retain its shape and the structure when the Airy beam propagates through the atmosphere due to thermal blooming except for the short propagation distance, or the short time, or the low beam power. The thermal blooming results in a central dip of the center lobe, and causes the center lobe to spread and decrease. In contrast with the center lobe, the side lobes are less affected by thermal blooming, such that the intensity maximum of the side lobe may be larger than that of the center lobe. However, the cross wind can reduce the effect of thermal blooming. When there exists the cross wind velocity vx in x direction, the dependence of centroid position in x direction on vx is not monotonic, and there exists a minimum, but the centroid position in y direction is nearly independent of vx.

  18. Airy minimum crossing θcm = 90° at Elab = 124 MeV for the 16O + 16O system

    NASA Astrophysics Data System (ADS)

    Kondo, Y.; Sugiyama, Y.; Tomita, T.; Yamanouchi, Y.; Ikezoe, H.; Ideno, K.; Hamada, S.; Sugimitsu, T.; Hijiya, M.; Fujita, H.

    1996-02-01

    We have measured the elastic scattering angular distribution for the 16O + 16O system at Elab = 124 MeV, where a prominent minimum has been observed in the θcm = 90° excitation function. The measured angular distribution shows modulated Airy structures at large angles with a dip at θcm = 90°. It is concluded that the prominent minimum in the excitation function is due to an Airy minimum, most likely to be the third member, crossing 90° at that energy.

  19. Improved Intrapulse Raman Scattering Control via Asymmetric Airy Pulses

    NASA Astrophysics Data System (ADS)

    Hu, Yi; Tehranchi, Amirhossein; Wabnitz, Stefan; Kashyap, Raman; Chen, Zhigang; Morandotti, Roberto

    2015-02-01

    We experimentally demonstrate the possibility of tuning the frequency of a laser pulse via the use of an Airy pulse-seeded soliton self-frequency shift. The intrinsically asymmetric nature of Airy pulses, typically featured by either leading or trailing oscillatory tails (relatively to the main lobe), is revealed through the nonlinear generation of both a primary and a secondary Raman soliton self-frequency shift, a phenomenon which is driven by the soliton fission processes. The resulting frequency shift can be carefully controlled by using time-reversed Airy pulses or, alternatively, by applying an offset to the cubic phase modulation used to generate the pulses. When compared with the use of conventional chirped Gaussian pulses, our technique brings about unique advantages in terms of both efficient frequency tuning and feasibility, along with the generation and control of multicolor Raman solitons with enhanced tunability. Our theoretical analysis agrees well with our experimental observations.

  20. Optical trapping and manipulation of Mie particles with Airy beam

    NASA Astrophysics Data System (ADS)

    Zhao, Ziyu; Zang, Weiping; Tian, Jianguo

    2016-02-01

    In this paper we calculate the radiation forces and moving trajectories of Mie particles induced by 1D Airy beams using the plane wave spectrum method and arbitrary beam theory. Numerical results show that both the transverse and the longitudinal radiation forces are deeply dependent on the relative refractive index, radii and positions of the scattering particles illuminated by the Airy beam. Due to the radiation forces, Mie particles with different radii and initial positions can be dragged into the nearest main intensity lobes, and move along parabolic trajectories in the direction of the Poynting vector. At the ends of these trajectories, in the presence of Brownian force, the trapped scattering particles show irregular Brownian movement near their equilibrium positions. This characteristic property of Airy beams enables optical sorting to be used more easily in the colloidal and biological sciences.

  1. Airy-Kaup-Kupershmidt filters applied to digital image processing

    NASA Astrophysics Data System (ADS)

    Hoyos Yepes, Laura Cristina

    2015-09-01

    The Kaup-Kupershmidt operator is applied to the two-dimensional solution of the Airy-diffusion equation and the resulting filter is applied via convolution to image processing. The full procedure is implemented using Maple code with the package ImageTools. Some experiments were performed using a wide category of images including biomedical images generated by magnetic resonance, computarized axial tomography, positron emission tomography, infrared and photon diffusion. The Airy-Kaup-Kupershmidt filter can be used as a powerful edge detector and as powerful enhancement tool in image processing. It is expected that the Airy-Kaup-Kupershmidt could be incorporated in standard programs for image processing such as ImageJ.

  2. Super-resolution imaging based on virtual Airy spot

    NASA Astrophysics Data System (ADS)

    Liu, Zhengjun; Guo, Cheng; Cui, Junning; Wu, Qun

    2015-02-01

    Based on the theoretical model of Airy spot, a method is proposed for improving the imaging speed from confocal microscopy. The virtual Airy spot is designed for obtaining the pattern on CCD at detecting plane. Here the size of the spot is determined by the parameters of imaging system and intensity data from point detector, which can receive data quicker than CCD. The treatment can improve the speed of imaging comparing with CCD at receiving end. The virtual structured detection is also utilized for generating high-resolution image. Some numerical simulation results are provided for demonstrating the validity of the proposed method.

  3. Annular arrayed-waveguide fiber for autofocusing Airy-like beams.

    PubMed

    Deng, Hongchang; Yuan, Yonggui; Yuan, Libo

    2016-02-15

    We propose and theoretically demonstrate a novel optical fiber with an annular arrayed-waveguide to implement Airy phase and amplitude modulation, and generate an abruptly autofocusing circular Airy beam. The properties of wave propagation in Airy fiber and free space are studied by using the coupled-mode theory and angular spectrum method. The calculated results show that the output beam from such a fiber has a circular Airy-like pattern and can autofocus with the intensity maxima following a parabolic trajectory. We also show that the position of the focus point of the output beam from the Airy fiber can be easily controlled by changing input wavelength.

  4. Photorefractive and computational holography in the experimental generation of Airy beams

    NASA Astrophysics Data System (ADS)

    Suarez, Rafael A. B.; Vieira, Tarcio A.; Yepes, Indira S. V.; Gesualdi, Marcos R. R.

    2016-05-01

    In this paper, we present the experimental generation of Airy beams via computational and photorefractive holography. Experimental generation of Airy beams using conventional optical components presents several difficulties and a practically infeasible. Thus, the optical generation of Airy beams has been made from the optical reconstruction of a computer generated hologram implemented by a spatial light modulator. In the photorefractive holography technique, being used for the first time to our knowledge, the hologram of an Airy beam is constructed (recorded) and reconstructed (read) optically in a nonlinear photorefractive medium. The Airy beam experimental realization was made by a setup of computational and photorefractive holography using a photorefractive Bi12 TiO20 crystal as holographic recording medium. Airy beams and Airy beam arrays were obtained experimentally in accordance with the predicted theory; with excellent prospects for applications in optical trapping and optical communications systems.

  5. Non-diffracting super-airy beam with intensified main lobe

    NASA Astrophysics Data System (ADS)

    Singh, Brijesh Kumar; Remez, Roei; Tsur, Yuval; Arie, Ady

    2016-04-01

    We study, theoretically and experimentally, the concept of non-diffracting super-Airy beam, where the main lobe of the beam is observed to be nearly half in size and with increased intensity compared to the main lobe of the Airy beam. However, reducing the main lobe size does not affect the transverse acceleration and non-spreading features of the beam. Furthermore, we observed that during propagation, super Airy main lobe shows faster self-reconstruction after an obstruction than the Airy main lobe. Therefore, we envision that specifically, a beam with a smaller lobe size and higher intensity can out-perform the Airy beam for applications such as nonlinear optics, curved plasma generation, laser micromachining, and micro- particle manipulation, while the faster reconstruction property of the super-Airy main lobe can surpass the Airy beam in applications of scattering and turbulent media.

  6. Two-dimensional χ2 solitons generated by the downconversion of Airy waves.

    PubMed

    Mayteevarunyoo, Thawatchai; Malomed, Boris A

    2016-07-01

    Conversion of truncated Airy waves (AWs) carried by the second-harmonic (SH) component into axisymmetric χ2 solitons is considered in a 2D system with quadratic nonlinearity. The spontaneous conversion is driven by the parametric instability of the SH wave. The input in the form of the AW vortex is also considered. As a result, one, two, or three stable solitons emerge in a well-defined form, unlike the recently studied 1D setting, where the picture is obscured by radiation jets. Shares of the total power captured by the emerging solitons and conversion efficiency are found as functions of parameters of the AW input. PMID:27367065

  7. Thyroid function and stress hormones in children with stress hyperglycemia.

    PubMed

    Bordbar, Mohammad Reza; Taj-Aldini, Reza; Karamizadeh, Zohre; Haghpanah, Sezaneh; Karimi, Mehran; Omrani, Gholam Hossein

    2012-12-01

    The purpose of the study is to determine the prevalence of stress hyperglycemia and to investigate how thyroid and stress hormones alter during stress hyperglycemia in children admitted to pediatric emergency wards. A prospective cross-sectional study was conducted in children, less than 19 years old, who were admitted to pediatric emergency wards of Nemazee and Dastgheib Hospitals, Shiraz, Southern Iran. Those patients taking steroids, beta-agonists or intravenously administered glucose before venipuncture, and patients with diabetes mellitus (DM) or thyroid diseases were excluded. Children with blood glucose ≥ 150 mg/dL during admission were regarded as cases. The controls were age- and- sex- matched, euglycemic children. Stress hormones including cortisol, insulin, growth hormone, and prolactin were measured, and thyroid function was tested with a radioimmunoassay (RIA) method in all cases and controls. The results showed that among 1,054 screened children, 39 cases (3.7 %) had stress hyperglycemia and 89 controls were included in the study. The occurrence of hyperglycemia was independent of sex, but it occurred mostly in children under 6 years old. Hyperglycemia occurred more frequently in patients with a positive family history of DM (odds ratio = 3.2, 95 % CI = 1.3-7.9, and P = 0.009). There were no significant differences between cases and controls regarding any hormones except higher cortisol, and lower total T3 and T4 in cases compared with controls. Neither of cases developed diabetes in the 24-month follow-up period. These findings led us to the conclusion that stress hyperglycemia is occasionally seen in critically ill patients. Among the stress hormones measured, only cortisol increased during hyperglycemia. It seems that hyperglycemia is not an important risk factor for future diabetes.

  8. On the joint distribution of the maximum and its position of the Airy2 process minus a parabola

    NASA Astrophysics Data System (ADS)

    Baik, Jinho; Liechty, Karl; Schehr, Grégory

    2012-08-01

    The maximal point of the Airy2 process minus a parabola is believed to describe the scaling limit of the end-point of the directed polymer in a random medium. This was proved to be true for a few specific cases. Recently, two different formulas for the joint distribution of the location and the height of this maximal point were obtained, one by Moreno Flores, Quastel, and Remenik, and the other by Schehr. The first formula is given in terms of the Airy function and an associated operator, and the second formula is expressed in terms of the Lax pair equations of the Painlevé II equation. We give a direct proof that these two formulas are the same.

  9. Functional stress modification after high condylectomy surgery.

    PubMed

    Alexandridis, C; Caputo, A A; Eliades, G C

    1991-07-01

    Surgical removal of the head of the condyles inevitably leads to radical redistribution of loads applied to the mandible. The nature of this redistribution can have important implications on the surgical approach and subsequent reconstructive procedures. The purpose of this investigation was to visualize photoelastically the functionally delivered stresses after high condylectomy surgery. Three identical models of a dentate human mandible were constructed from a photoelastic material. One mandible simulated a unilateral and the other simulated a bilateral high condylectomy. The third mandible had both condyles intact and served as basis for comparisons. Silicone implants were placed on the sectioned condylar heads. The condyles, with the silicone implants, were fitted into simulated fossae and the mandibles were loaded unilaterally and bilaterally. The resulting stresses were observed and photographed in the field of a circular polariscope. Substantial differences in load-generated stresses were observed as a result of both unilateral and bilateral condylectomies, compared to the normal case. The most severe stress conditions occurred with the unilateral condylectomy, where stresses associated with torsion were most evident. PMID:1890533

  10. Repositioning and steering laser beam power via coherent combination of multiple Airy beams.

    PubMed

    Zhang, Ze; Ye, Zhuoyi; Song, Daohong; Zhang, Peng; Chen, Zhigang

    2013-12-10

    We study numerically and experimentally laser coherent combination (LCC) with multiple one- or two-dimensional Airy beams. It is shown that the method of LCC using Airy beams leads to a higher combining efficiency and a better feature of propagation than that using conventional Gaussian beams. Based on such coherent Airy beams combination, we propose a laser steering approach that could achieve large-angle beam steering (over 0.6°) without the need of using any mechanical steering component.

  11. Propagation of Airy Gaussian vortex beams in uniaxial crystals

    NASA Astrophysics Data System (ADS)

    Weihao, Yu; Ruihuang, Zhao; Fu, Deng; Jiayao, Huang; Chidao, Chen; Xiangbo, Yang; Yanping, Zhao; Dongmei, Deng

    2016-04-01

    The propagation dynamics of the Airy Gaussian vortex beams in uniaxial crystals orthogonal to the optical axis has been investigated analytically and numerically. The propagation expression of the beams has been obtained. The propagation features of the Airy Gaussian vortex beams are shown with changes of the distribution factor and the ratio of the extraordinary refractive index to the ordinary refractive index. The correlations between the ratio and the maximum intensity value during the propagation, and its appearing distance have been investigated. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374108, 11374107, 10904041, and 11547212), the Foundation of Cultivating Outstanding Young Scholars of Guangdong Province, China, the CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, the National Training Program of Innovation and Entrepreneurship for Undergraduates (Grant No. 2015093), and the Science and Technology Projects of Guangdong Province, China (Grant No. 2013B031800011).

  12. Propagation of Airy Gaussian vortex beams in uniaxial crystals

    NASA Astrophysics Data System (ADS)

    Weihao, Yu; Ruihuang, Zhao; Fu, Deng; Jiayao, Huang; Chidao, Chen; Xiangbo, Yang; Yanping, Zhao; Dongmei, Deng

    2016-04-01

    The propagation dynamics of the Airy Gaussian vortex beams in uniaxial crystals orthogonal to the optical axis has been investigated analytically and numerically. The propagation expression of the beams has been obtained. The propagation features of the Airy Gaussian vortex beams are shown with changes of the distribution factor and the ratio of the extraordinary refractive index to the ordinary refractive index. The correlations between the ratio and the maximum intensity value during the propagation, and its appearing distance have been investigated. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374108, 11374107, 10904041, and 11547212), the Foundation of Cultivating Outstanding Young Scholars of Guangdong Province, China, the CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, the National Training Program of Innovation and Entrepreneurship for Undergraduates (Grant No. 2015093), and the Science and Technology Projects of Guangdong Province, China (Grant No. 2013B031800011).

  13. Interaction of Airy-Gaussian beams in saturable media

    NASA Astrophysics Data System (ADS)

    Zhou, Meiling; Peng, Yulian; Chen, Chidao; Chen, Bo; Peng, Xi; Deng, Dongmei

    2016-08-01

    Based on the nonlinear Schrödinger equation, the interactions of the two Airy-Gaussian components in the incidence are analyzed in saturable media, under the circumstances of the same amplitude and different amplitudes, respectively. It is found that the interaction can be both attractive and repulsive depending on the relative phase. The smaller the interval between two Airy-Gaussian components in the incidence is, the stronger the intensity of the interaction. However, with the equal amplitude, the symmetry is shown and the change of quasi-breathers is opposite in the in-phase case and out-of-phase case. As the distribution factor is increased, the phenomena of the quasi-breather and the self-accelerating of the two Airy-Gaussian components are weakened. When the amplitude is not equal, the image does not have symmetry. The obvious phenomenon of the interaction always arises on the side of larger input power in the incidence. The maximum intensity image is also simulated. Many of the characteristics which are contained within other images can also be concluded in this figure. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374108 and 10904041), the Foundation for the Author of Guangdong Province Excellent Doctoral Dissertation (Grant No. SYBZZXM201227), and the Foundation of Cultivating Outstanding Young Scholars (“Thousand, Hundred, Ten” Program) of Guangdong Province, China. CAS Key Laboratory of Geospace Environment, University of Science and Technology of China.

  14. Slow-light Airy wave packets and their active control via electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Hang, Chao; Huang, Guoxiang

    2013-07-01

    We propose a scheme to generate (3+1)-dimensional slow-light Airy wave packets in a resonant Λ-type three-level atomic gas via electromagnetically induced transparency. We show that in the absence of dispersion the Airy wave packets formed by a probe field consist of two Airy wave packets accelerated in transverse directions and a longitudinal Gaussian pulse with a constant propagating velocity lowered to 10-5c (c is the light speed in vacuum). We also show that in the presence of dispersion it is possible to generate another type of slow-light Airy wave packet consisting of two Airy beams in transverse directions and an Airy wave packet in the longitudinal direction. In this case, the longitudinal velocity of the Airy wave packet can be further reduced during propagation. Additionally, we further show that the transverse accelerations (or bending) of the both types of slow-light Airy wave packets can be completely eliminated and the motional trajectories of them can be actively manipulated and controlled by using a Stern-Gerlach gradient magnetic field.

  15. Nonlinear evolution of Airy-like beams generated by modulated waveguide arrays.

    PubMed

    Cao, Zheng; Tan, Qinggui; Li, Xiaojun; Qi, Xinyuan

    2016-08-20

    We numerically study the formation of modulated waveguide generated Airy-like beams and their subsequent evolution in homogeneous medium. The results show that the Airy-like beams could be generated from narrow Gaussian beams propagating in one-dimensional transverse separation modulated unbent, cosine bent, or logarithm bent waveguide arrays, respectively. The waveguide-generated Airy-like beams maintain their characteristics when propagating without nonlinearity or under the self-defocusing nonlinearity in homogeneous medium, while the beams are distorted under the self-focusing nonlinearity. The deformation depends on the waveguide bending and the outgoing angles of the Airy-like beams. Our results provide a new way to generate and manipulate the Airy-like beam.

  16. Impacts of cross-phase modulation on modulation instability of Airy pulses

    NASA Astrophysics Data System (ADS)

    Cheng, Yingkai; Fu, Xiquan; Bai, Yanfeng

    2016-10-01

    The modulation instability (MI) of Airy pulses with the influence of cross-phase modulation is studied based on the coupled nonlinear Schrödinger equations in nonlinear media. The main lobe of Airy pulses can be manifested as breakup of MI under interaction with higher power pumped solitons, although the power of Airy pulses is small. By comparing the main lobe's gain spectrum of MI, the gain spectrum has gradually improved with the increase of power of pumped solitons. The gain spectrum of MI of the main lobe is inversely proportional to the truncation coefficient, and then it gradually approaches to that of Gauss pulses with the truncation coefficient increasing to 1. For the side lobes of Airy pulses, there are similar MI but smaller gain spectrum than the main lobe when the pumped solitons is overlapping with corresponding ones of Airy pulses.

  17. Chirped self-healing Airy pulses compression in silicon waveguides under fourth-order dispersion

    NASA Astrophysics Data System (ADS)

    Mandeng Mandeng, Lucien; Tchawoua, Clément

    2013-03-01

    We present the compression of Airy pulses in silicon-on-insulator (SOI) waveguides under the fourth-order dispersion (FOD) using the variational approach that involves Rayleigh's dissipation function (RDF). All the pulse characteristics are under the influence of the two-photon and the frequency-carrier absorptions. In a quasi-linear approximation, the pulse compression conditions induced by the interaction of the group-velocity dispersion (GVD), the chirp and the FOD are derived. In the nonlinear case, the self-phase modulation (SPM), the two-photon absorption (TPA) and the free-carrier absorption (FCA) reduce the length of compression in a propagation regime of normal GVD, positive chirp and a negative value of FOD. The TPA reduces the maximal power reached than the SPM while the FCA rather increases its value. These results are confirmed in the general case where they all interact with the linear dispersion terms of the SOI waveguide.

  18. Quantum polarization fluctuations of an Airy beam in turbulent atmosphere in a slant path.

    PubMed

    Yin, Xia; Zhang, Licheng

    2016-07-01

    Polarization of light has many applications in quantum information processing, including quantum teleportation and dense coding. In this paper, we investigate the polarization fluctuations of Airy beams propagating in a slant turbulent channel under the "few-photon" limit. Using the quantum Stokes parameters and the quantum degree of polarization, we demonstrate that the degree of polarization of Airy beams increases significantly with the large number of the detection photons, and a higher photon-number level can retain the stability of polarization. Numerical simulations show that the longer propagation distance and the stronger turbulence will lead to less oscillatory behaviors and a decrease in the polarization degree of Airy beams, but a bigger exponential truncation factor will cause an increase in the polarization degree of Airy beams. In contrast with Gaussian beams, the degree of polarization of Airy beams is less affected by atmospheric turbulence and propagation distance under the same conditions, which means that Airy beams possess a resilient ability against turbulence-induced perturbations. These results indicate that Airy beams have great potential for applications in long-distance free-space optical communications to improve the performance of a polarization-encoded free-space quantum communication system.

  19. Quantum polarization fluctuations of an Airy beam in turbulent atmosphere in a slant path.

    PubMed

    Yin, Xia; Zhang, Licheng

    2016-07-01

    Polarization of light has many applications in quantum information processing, including quantum teleportation and dense coding. In this paper, we investigate the polarization fluctuations of Airy beams propagating in a slant turbulent channel under the "few-photon" limit. Using the quantum Stokes parameters and the quantum degree of polarization, we demonstrate that the degree of polarization of Airy beams increases significantly with the large number of the detection photons, and a higher photon-number level can retain the stability of polarization. Numerical simulations show that the longer propagation distance and the stronger turbulence will lead to less oscillatory behaviors and a decrease in the polarization degree of Airy beams, but a bigger exponential truncation factor will cause an increase in the polarization degree of Airy beams. In contrast with Gaussian beams, the degree of polarization of Airy beams is less affected by atmospheric turbulence and propagation distance under the same conditions, which means that Airy beams possess a resilient ability against turbulence-induced perturbations. These results indicate that Airy beams have great potential for applications in long-distance free-space optical communications to improve the performance of a polarization-encoded free-space quantum communication system. PMID:27409692

  20. Racism-Related Stress, General Life Stress, and Psychological Functioning among Black American Women

    ERIC Educational Resources Information Center

    Pieterse, Alex L.; Carter, Robert T.; Ray, Kilynda V.

    2013-01-01

    The relationship between general life stress, perceived racism, and psychological functioning was explored in a sample of 118 Black American women. Findings indicate that racism-related stress was not a significant predictor of psychological functioning when controlling for general life stress. Perceived racism was positively associated with…

  1. Chronic stress and sexual function in women

    PubMed Central

    Hamilton, Lisa Dawn; Meston, Cindy M.

    2014-01-01

    Introduction Chronic stress is known to have negative effects on reproduction, but little is known about how it affects the sexual response cycle. The present study examined the relationship between chronic stress and sexual arousal and the mechanisms that mediate this relationship. Aim To test the relationship between chronic stress and sexual arousal and identify mechanisms that may explain this relationship. We predicted that women experiencing high levels of chronic stress would show lower levels of genital arousal & DHEAS and higher levels of cortisol and cognitive distraction compared to women with average levels of stress. Methods Women who were categorized as high in chronic stress (high stress group, n = 15) or average in chronic stress (average stress group; n = 15) provided saliva samples and watched an erotic film while having their genital and psychological arousal measured. Main Outcome Measures Main outcome measures were vaginal pulse amplitude, psychological arousal, salivary cortisol, salivary DHEAS, and heart rate and compared them between women with high and average levels of chronic stress. Results Women in the high stress group had lower levels of genital, but not psychological arousal, had higher levels of cortisol, and reported more distraction during the erotic film than women in the average stress group. The main predictor of decreased genital sexual arousal was participants’ distraction scores. Conclusions High levels of chronic stress were related to lower levels of genital sexual arousal. Both psychological (distraction) and hormonal (increased cortisol) factors were related to the lower levels of sexual arousal seen in women high in chronic stress, but distraction was the only significant predictor when controlling for other variables. PMID:23841462

  2. Control on the anomalous interactions of Airy beams in nematic liquid crystals.

    PubMed

    Shen, Ming; Li, Wei; Lee, Ray-Kuang

    2016-04-18

    We reveal a controllable manipulation of anomalous interactions between Airy beams in nonlocal nematic liquid crystals numerically. With the help of an in-phase fundamental Gaussian beam, attraction between in-phase Airy beams can be suppressed or become a repulsive one to each other; whereas the attraction can be strengthened when the Gaussian beam is out-of-phase. In contrast to the repulsive interaction in local media, stationary bound states of breathing Airy soliton pairs are found in nematic liquid crystals.

  3. Subacute stress and chronic stress interact to decrease intestinal barrier function in rats.

    PubMed

    Lauffer, Adriana; Vanuytsel, Tim; Vanormelingen, Christophe; Vanheel, Hanne; Salim Rasoel, Shadea; Tóth, Joran; Tack, Jan; Fornari, Fernando; Farré, Ricard

    2016-01-01

    Psychological stress increases intestinal permeability, potentially leading to low-grade inflammation and symptoms in functional gastrointestinal disorders. We assessed the effect of subacute, chronic and combined stress on intestinal barrier function and mast cell density. Male Wistar rats were allocated to four experimental groups (n = 8/group): 1/sham; 2/subacute stress (isolation and limited movement for 24 h); 3/chronic crowding stress for 14 days and 4/combined subacute and chronic stress. Jejunum and colon were collected to measure: transepithelial electrical resistance (TEER; a measure of epithelial barrier function); gene expression of tight junction molecules; mast cell density. Plasma corticosterone concentration was increased in all three stress conditions versus sham, with highest concentrations in the combined stress condition. TEER in the jejunum was decreased in all stress conditions, but was significantly lower in the combined stress condition than in the other groups. TEER in the jejunum correlated negatively with corticosterone concentration. Increased expression of claudin 1, 5 and 8, occludin and zonula occludens 1 mRNAs was detected after subacute stress in the jejunum. In contrast, colonic TEER was decreased only after combined stress, and the expression of tight junction molecules was unaltered. Increased mast cell density was observed in the chronic and combined stress condition in the colon only. In conclusion, our data show that chronic stress sensitizes the gastrointestinal tract to the effects of subacute stress on intestinal barrier function; different underlying cellular and molecular alterations are indicated in the small intestine versus the colon.

  4. Quantitative comparison of self-healing ability between Bessel–Gaussian beam and Airy beam

    SciTech Connect

    Wen, Wei; Chu, Xiuxiang

    2015-09-15

    The self-healing ability during propagation process is one of the most important properties of non-diffracting beams. This ability has crucial advantages to light sheet-based microscopy to reduce scattering artefacts, increase the quality of the image and enhance the resolution of microscopy. Based on similarity between two infinite-dimensional complex vectors in Hilbert space, the ability to a Bessel–Gaussian beam and an Airy beam have been studied and compared. Comparing the evolution of the similarity of Bessel–Gaussian beam with Airy beam under the same conditions, we find that Bessel–Gaussian beam has stronger self-healing ability and is more stable than that of Airy beam. To confirm this result, the intensity profiles of Bessel–Gaussian beam and Airy beam with different similarities are numerically calculated and compared.

  5. AIRY: a complete tool for the simulation and the reconstruction of astronomical images

    NASA Astrophysics Data System (ADS)

    La Camera, Andrea; Carbillet, Marcel; Olivieri, Chiara; Boccacci, Patrizia; Bertero, Mario

    2012-07-01

    The Software Package AIRY (acronym for Astronomical Image Restoration in interferometrY) is a software tool designed to perform simulation and/or deconvolution of images of Fizeau interferometers as well as of any kind of optical telescopes. AIRY is written in IDL and is a Software Package of the CADS Problem Solving Environment (PSE): it is made of a set of modules, each one representing a specific task. We present here the last version of the software, arrived at its sixth release after 10 years of development. This version of AIRY summarizes the work done in recent years by our group, both on AIRY and on AIRY-LN, the version of the software dedicated to the image restoration of LINC-NIRVANA (LN), the Fizeau interferometer of the Large Binocular Telescope (LBT). AIRY v.6.0 includes a renewed deconvolution module implementing regularizations, accelerations, and stopping criteria of standard algorithms, such as OSEM and Richardson-Lucy. Several modules of AIRY have been improved and, in particular, the one used for the extraction and extrapolatioThe Software Package AIRY (acronym for Astronomical Image Restoration in interferometrY) is a software tool designed to perform simulation and/or deconvolution of images of Fizeau interferometers as well as of any kind of optical telescopes. AIRY is written in IDL and is a Software Package of the CAOS Problem Solving Environment (PSE): it is made of a set of modules, each one representing a speci_c task. We present here the last version of the software, arrived at its sixth release after 10 years of development. This version of AIRY summarizes the work done in recent years by our group, both on AIRY and on AIRY-LN, the version of the software dedicated to the image restoration of LINC-NIRVANA (LN), the Fizeau interferometer of the Large Binocular Telescope (LBT). AIRY v.6.0 includes a renewed deconvolution module implementing regularizations, accelerations, and stopping criteria of standard algorithms, such as OSEM and

  6. Stress induced changes in testis function.

    PubMed

    López-Calderón, A; Ariznavarreta, C; González-Quijano, M I; Tresguerres, J A; Calderón, M D

    1991-01-01

    The mechanism through which chronic stress inhibits the hypothalamic-pituitary-testicular axis has been investigated. Chronic restraint stress decreases testosterone secretion, an effect that is associated with a decrease in plasma gonadotropin levels. In chronically stressed rats there was a decrease in hypothalamic luteinizing hormone-releasing hormone (LHRH) content and the response on plasma gonadotropins to LHRH administration was enhanced. Thus the inhibitory effect of chronic stress on plasma LH and FSH levels seems not to be due to a reduction in pituitary responsiveness to LHRH, but rather to a modification in LHRH secretion. It has been suggested that beta-endorphin might interfere with hypothalamic LHRH secretion during stress. Chronic immobilization did not modify hypothalamic beta-endorphin, while an increase in pituitary beta-endorphin secretion was observed. Since we cannot exclude that changes in beta-endorphin secreted by the pituitary or other opioids may play some role in the stress-induced decrease in LHRH secretion, the effect of naltrexone administration on plasma gonadotropin was studied in chronically stressed rats. Naltrexone treatment did not modify the decrease in plasma concentrations of LH or FSH. These findings suggest that the inhibitory effect of restraint on the testicular axis is exerted at hypothalamic level by some mechanism other than opioids.

  7. Stress induced changes in testis function.

    PubMed

    López-Calderón, A; Ariznavarreta, C; González-Quijano, M I; Tresguerres, J A; Calderón, M D

    1991-01-01

    The mechanism through which chronic stress inhibits the hypothalamic-pituitary-testicular axis has been investigated. Chronic restraint stress decreases testosterone secretion, an effect that is associated with a decrease in plasma gonadotropin levels. In chronically stressed rats there was a decrease in hypothalamic luteinizing hormone-releasing hormone (LHRH) content and the response on plasma gonadotropins to LHRH administration was enhanced. Thus the inhibitory effect of chronic stress on plasma LH and FSH levels seems not to be due to a reduction in pituitary responsiveness to LHRH, but rather to a modification in LHRH secretion. It has been suggested that beta-endorphin might interfere with hypothalamic LHRH secretion during stress. Chronic immobilization did not modify hypothalamic beta-endorphin, while an increase in pituitary beta-endorphin secretion was observed. Since we cannot exclude that changes in beta-endorphin secreted by the pituitary or other opioids may play some role in the stress-induced decrease in LHRH secretion, the effect of naltrexone administration on plasma gonadotropin was studied in chronically stressed rats. Naltrexone treatment did not modify the decrease in plasma concentrations of LH or FSH. These findings suggest that the inhibitory effect of restraint on the testicular axis is exerted at hypothalamic level by some mechanism other than opioids. PMID:1958548

  8. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses

    PubMed Central

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention. PMID:26904076

  9. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses.

    PubMed

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention.

  10. Periodic inversion and phase transition of finite energy Airy beams in a medium with parabolic potential.

    PubMed

    Zhang, Yiqi; Belić, Milivoj R; Zhang, Lei; Zhong, Weiping; Zhu, Dayu; Wang, Ruimin; Zhang, Yanpeng

    2015-04-20

    We study periodic inversion and phase transition of normal, displaced, and chirped finite energy Airy beams propagating in a parabolic potential. This propagation leads to an unusual oscillation: for half of the oscillation period the Airy beam accelerates in one transverse direction, with the main Airy beam lobe leading the train of pulses, whereas in the other half of the period it accelerates in the opposite direction, with the main lobe still leading - but now the whole beam is inverted. The inversion happens at a critical point, at which the beam profile changes from an Airy profile to a Gaussian one. Thus, there are two distinct phases in the propagation of an Airy beam in the parabolic potential - the normal Airy and the single-peak Gaussian phase. The length of the single-peak phase is determined by the size of the decay parameter: the smaller the decay, the smaller the length. A linear chirp introduces a transverse displacement of the beam at the phase transition point, but does not change the location of the point. A quadratic chirp moves the phase transition point, but does not affect the beam profile. The two-dimensional case is discussed briefly, being equivalent to a product of two one-dimensional cases.

  11. Polarization-controllable Airy beams generated via a photoaligned director-variant liquid crystal mask

    NASA Astrophysics Data System (ADS)

    Wei, Bing-Yan; Chen, Peng; Hu, Wei; Ji, Wei; Zheng, Li-Yang; Ge, Shi-Jun; Ming, Yang; Chigrinov, Vladimir; Lu, Yan-Qing

    2015-12-01

    Researches on Airy beams have grown explosively since the first demonstration in 2007 due to the distinguishing properties of nondiffraction, transverse acceleration and self-healing. To date, a simple and compact approach for generating Airy beams in high quality and efficiency has remained challenging. Here, we propose and demonstrate a liquid crystal (LC) polarization Airy mask (PAM) featured by spatially variant LC azimuthal director. The PAM is fabricated through photoaligning LC via a polarization-sensitive alignment agent suophonic azo dye SD1. Thanks to the special design, a novel feature of polarization-controllable switch between dual Airy beams of orthogonal circular polarization is presented. The molecular-level continuity of LC director significantly improves the quality and efficiency of resultant Airy beams. Besides, the PAM can handle intense light due to the absence of absorptive electrodes. Additional merits of compact size, low cost and broad wavelength tolerance are also exhibited. This work settles a fundamental requirement for Airy beam applications of optical manipulations, biology science and even some uncharted territories.

  12. Polarization-controllable Airy beams generated via a photoaligned director-variant liquid crystal mask.

    PubMed

    Wei, Bing-Yan; Chen, Peng; Hu, Wei; Ji, Wei; Zheng, Li-Yang; Ge, Shi-Jun; Ming, Yang; Chigrinov, Vladimir; Lu, Yan-Qing

    2015-01-01

    Researches on Airy beams have grown explosively since the first demonstration in 2007 due to the distinguishing properties of nondiffraction, transverse acceleration and self-healing. To date, a simple and compact approach for generating Airy beams in high quality and efficiency has remained challenging. Here, we propose and demonstrate a liquid crystal (LC) polarization Airy mask (PAM) featured by spatially variant LC azimuthal director. The PAM is fabricated through photoaligning LC via a polarization-sensitive alignment agent suophonic azo dye SD1. Thanks to the special design, a novel feature of polarization-controllable switch between dual Airy beams of orthogonal circular polarization is presented. The molecular-level continuity of LC director significantly improves the quality and efficiency of resultant Airy beams. Besides, the PAM can handle intense light due to the absence of absorptive electrodes. Additional merits of compact size, low cost and broad wavelength tolerance are also exhibited. This work settles a fundamental requirement for Airy beam applications of optical manipulations, biology science and even some uncharted territories. PMID:26626737

  13. Polarization-controllable Airy beams generated via a photoaligned director-variant liquid crystal mask

    PubMed Central

    Wei, Bing-Yan; Chen, Peng; Hu, Wei; Ji, Wei; Zheng, Li-Yang; Ge, Shi-Jun; Ming, Yang; Chigrinov, Vladimir; Lu, Yan-Qing

    2015-01-01

    Researches on Airy beams have grown explosively since the first demonstration in 2007 due to the distinguishing properties of nondiffraction, transverse acceleration and self-healing. To date, a simple and compact approach for generating Airy beams in high quality and efficiency has remained challenging. Here, we propose and demonstrate a liquid crystal (LC) polarization Airy mask (PAM) featured by spatially variant LC azimuthal director. The PAM is fabricated through photoaligning LC via a polarization-sensitive alignment agent suophonic azo dye SD1. Thanks to the special design, a novel feature of polarization-controllable switch between dual Airy beams of orthogonal circular polarization is presented. The molecular-level continuity of LC director significantly improves the quality and efficiency of resultant Airy beams. Besides, the PAM can handle intense light due to the absence of absorptive electrodes. Additional merits of compact size, low cost and broad wavelength tolerance are also exhibited. This work settles a fundamental requirement for Airy beam applications of optical manipulations, biology science and even some uncharted territories. PMID:26626737

  14. Polarization-controllable Airy beams generated via a photoaligned director-variant liquid crystal mask.

    PubMed

    Wei, Bing-Yan; Chen, Peng; Hu, Wei; Ji, Wei; Zheng, Li-Yang; Ge, Shi-Jun; Ming, Yang; Chigrinov, Vladimir; Lu, Yan-Qing

    2015-12-02

    Researches on Airy beams have grown explosively since the first demonstration in 2007 due to the distinguishing properties of nondiffraction, transverse acceleration and self-healing. To date, a simple and compact approach for generating Airy beams in high quality and efficiency has remained challenging. Here, we propose and demonstrate a liquid crystal (LC) polarization Airy mask (PAM) featured by spatially variant LC azimuthal director. The PAM is fabricated through photoaligning LC via a polarization-sensitive alignment agent suophonic azo dye SD1. Thanks to the special design, a novel feature of polarization-controllable switch between dual Airy beams of orthogonal circular polarization is presented. The molecular-level continuity of LC director significantly improves the quality and efficiency of resultant Airy beams. Besides, the PAM can handle intense light due to the absence of absorptive electrodes. Additional merits of compact size, low cost and broad wavelength tolerance are also exhibited. This work settles a fundamental requirement for Airy beam applications of optical manipulations, biology science and even some uncharted territories.

  15. Psychological stress and the function of male gonads.

    PubMed

    Jóźków, Paweł; Mędraś, Marek

    2012-01-01

    Stress is generally a natural phenomenon that affects behaviour, physiological processes, and neuroendocrine, neurochemical, neurological and immune responses. Many somatic and mental disorders are thought to result from chronic stress. Stress-induced gonadal dysfunction is not restricted to humans, but is observed in all higher animals. Stress-induced gonadal dysfunction comprises disturbances of the hypothalamic-pituitary-gonadal axis and of spermatogenesis. Various stressors induce changes in the secretion of neurotransmitters and hormones, such as CRH, ADH, beta-endorphins, somatostatin, VIP, PRL, GH, TSH, dopamine, serotonin, neuropeptide Y, melatonin, ACTH, glucocorticosteroids, catecholamines and androgens. In acute stress, testicular function is principally modified by cytokines and fluctuating concentrations of gonadotropins, while in chronic stress, hypogonadotropic hypogonadism and disruption of spermatogenesis of varying severity, including spermatogenetic arrest, are observed. In spite of the decades-long interest in the relationships between psychological stress and the function of male gonads, many questions in this area remain unanswered.

  16. Enhanced and unusual angle-dependent optical forces exerted on Mie particles by Airy surface plasmon wave

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Xue, Yanli; Li, Jiafang; Li, Zhi-Yuan

    2016-08-01

    In this paper, using an angular spectrum method, we develop an analytical theory for Airy surface plasmon wave excited in a classical Kretschmann setup. It is found that the center of an Airy surface plasmon polariton (SPP) wave has a giant positive lateral shift, and the sidelobes move forward along the surface. The intensity of the Airy SPP wave is greatly enhanced, the corresponding optical forces can be enhanced by more than one order of magnitude. Importantly, we show that the sidelobes of the Airy SPP beam can lead to the splitting of optical force spectra with the variation of incident angle, which is accompanied by strong oscillations emerging at the optimal metal layer thickness. Moreover, the effects of multiple scatterings of the Airy SPP wave between the particle and the metal layer are also discussed. The theoretical analysis could open up new perspectives for the applications of Airy beam in optical manipulation and surface-enhanced Raman scattering.

  17. Extended Kantorovich method for local stresses in composite laminates upon polynomial stress functions

    NASA Astrophysics Data System (ADS)

    Huang, Bin; Wang, Ji; Du, Jianke; Guo, Yan; Ma, Tingfeng; Yi, Lijun

    2016-06-01

    The extended Kantorovich method is employed to study the local stress concentrations at the vicinity of free edges in symmetrically layered composite laminates subjected to uniaxial tensile load upon polynomial stress functions. The stress fields are initially assumed by means of the Lekhnitskii stress functions under the plane strain state. Applying the principle of complementary virtual work, the coupled ordinary differential equations are obtained in which the solutions can be obtained by solving a generalized eigenvalue problem. Then an iterative procedure is established to achieve convergent stress distributions. It should be noted that the stress function based extended Kantorovich method can satisfy both the traction-free and free edge stress boundary conditions during the iterative processes. The stress components near the free edges and in the interior regions are calculated and compared with those obtained results by finite element method (FEM). The convergent stresses have good agreements with those results obtained by three dimensional (3D) FEM. For generality, various layup configurations are considered for the numerical analysis. The results show that the proposed polynomial stress function based extended Kantorovich method is accurate and efficient in predicting the local stresses in composite laminates and computationally much more efficient than the 3D FEM.

  18. Prenatal stress alters amygdala functional connectivity in preterm neonates.

    PubMed

    Scheinost, Dustin; Kwon, Soo Hyun; Lacadie, Cheryl; Sze, Gordon; Sinha, Rajita; Constable, R Todd; Ment, Laura R

    2016-01-01

    Exposure to prenatal and early-life stress results in alterations in neural connectivity and an increased risk for neuropsychiatric disorders. In particular, alterations in amygdala connectivity have emerged as a common effect across several recent studies. However, the impact of prenatal stress exposure on the functional organization of the amygdala has yet to be explored in the prematurely-born, a population at high risk for neuropsychiatric disorders. We test the hypothesis that preterm birth and prenatal exposure to maternal stress alter functional connectivity of the amygdala using two independent cohorts. The first cohort is used to establish the effects of preterm birth and consists of 12 very preterm neonates and 25 term controls, all without prenatal stress exposure. The second is analyzed to establish the effects of prenatal stress exposure and consists of 16 extremely preterm neonates with prenatal stress exposure and 10 extremely preterm neonates with no known prenatal stress exposure. Standard resting-state functional magnetic resonance imaging and seed connectivity methods are used. When compared to term controls, very preterm neonates show significantly reduced connectivity between the amygdala and the thalamus, the hypothalamus, the brainstem, and the insula (p < 0.05). Similarly, when compared to extremely preterm neonates without exposure to prenatal stress, extremely preterm neonates with exposure to prenatal stress show significantly less connectivity between the left amygdala and the thalamus, the hypothalamus, and the peristriate cortex (p < 0.05). Exploratory analysis of the combined cohorts suggests additive effects of prenatal stress on alterations in amygdala connectivity associated with preterm birth. Functional connectivity from the amygdala to other subcortical regions is decreased in preterm neonates compared to term controls. In addition, these data, for the first time, suggest that prenatal stress exposure amplifies these

  19. Prenatal stress alters amygdala functional connectivity in preterm neonates.

    PubMed

    Scheinost, Dustin; Kwon, Soo Hyun; Lacadie, Cheryl; Sze, Gordon; Sinha, Rajita; Constable, R Todd; Ment, Laura R

    2016-01-01

    Exposure to prenatal and early-life stress results in alterations in neural connectivity and an increased risk for neuropsychiatric disorders. In particular, alterations in amygdala connectivity have emerged as a common effect across several recent studies. However, the impact of prenatal stress exposure on the functional organization of the amygdala has yet to be explored in the prematurely-born, a population at high risk for neuropsychiatric disorders. We test the hypothesis that preterm birth and prenatal exposure to maternal stress alter functional connectivity of the amygdala using two independent cohorts. The first cohort is used to establish the effects of preterm birth and consists of 12 very preterm neonates and 25 term controls, all without prenatal stress exposure. The second is analyzed to establish the effects of prenatal stress exposure and consists of 16 extremely preterm neonates with prenatal stress exposure and 10 extremely preterm neonates with no known prenatal stress exposure. Standard resting-state functional magnetic resonance imaging and seed connectivity methods are used. When compared to term controls, very preterm neonates show significantly reduced connectivity between the amygdala and the thalamus, the hypothalamus, the brainstem, and the insula (p < 0.05). Similarly, when compared to extremely preterm neonates without exposure to prenatal stress, extremely preterm neonates with exposure to prenatal stress show significantly less connectivity between the left amygdala and the thalamus, the hypothalamus, and the peristriate cortex (p < 0.05). Exploratory analysis of the combined cohorts suggests additive effects of prenatal stress on alterations in amygdala connectivity associated with preterm birth. Functional connectivity from the amygdala to other subcortical regions is decreased in preterm neonates compared to term controls. In addition, these data, for the first time, suggest that prenatal stress exposure amplifies these

  20. Effects of Acute Laboratory Stress on Executive Functions

    PubMed Central

    Starcke, Katrin; Wiesen, Carina; Trotzke, Patrick; Brand, Matthias

    2016-01-01

    Recent research indicates that stress can affect executive functioning. However, previous results are mixed with respect to the direction and size of effects, especially when considering different subcomponents of executive functions. The current study systematically investigates the effects of stress on the five components of executive functions proposed by Smith and Jonides (1999): attention and inhibition; task management; planning; monitoring; and coding. Healthy participants (N = 40) were either exposed to the computerized version of the Paced Auditory Serial Addition Test as a stressor (N = 20), or to a rest condition (N = 20). Stress reactions were assessed with heart rate and subjective measures. After the experimental manipulation, all participants performed tasks that measure the different executive functions. The manipulation check indicates that stress induction was successful (i.e., the stress group showed a higher heart rate and higher subjective responses than the control group). The main results demonstrate that stressed participants show a poorer performance compared with unstressed participants in all executive subcomponents, with the exception of monitoring. Effect sizes for the tasks that reveal differences between stressed and unstressed participants are high. We conclude that the laboratory stressor used here overall reduced executive functioning. PMID:27065926

  1. Microstructural stress relaxation mechanics in functionally different tendons.

    PubMed

    Screen, H R C; Toorani, S; Shelton, J C

    2013-01-01

    Tendons experience widely varying loading conditions in vivo. They may be categorised by their function as either positional tendons, which are used for intricate movements and experience lower stress, or as energy storage tendons which act as highly stressed springs during locomotion. Structural and compositional differences between tendons are thought to enable an optimisation of their properties to suit their functional environment. However, little is known about structure-function relationships in tendon. This study adopts porcine flexor and extensor tendon fascicles as examples of high stress and low stress tendons, comparing their mechanical behaviour at the micro-level in order to understand their stress relaxation response. Stress-relaxation was shown to occur predominantly through sliding between collagen fibres. However, in the more highly stressed flexor tendon fascicles, more fibre reorganisation was evident when the tissue was exposed to low strains. By contrast, the low load extensor tendon fascicles appears to have less capacity for fibre reorganisation or shearing than the energy storage tendon, relying more heavily on fibril level relaxation. The extensor fascicles were also unable to sustain loads without rapid and complete stress relaxation. These findings highlight the need to optimise tendon repair solutions for specific tendons, and match tendon properties when using grafts in tendon repairs.

  2. Stress-Induced Tau Phosphorylation: Functional Neuroplasticity or Neuronal Vulnerability?

    PubMed Central

    Rissman, Robert A.

    2010-01-01

    Abnormally phosphorylated tau protein is a key component of the pathology seen in neurodegenerative tauopathies, such as Alzheimer's disease (AD). Despite its association with disease, tau phosphorylation (tau-P) also plays an important role in neuroplasticity, such as dendritic/synaptic remodeling seen in the hippocampus in response to environmental challenges, such as stress. To define the boundaries between neuroplasticity and neuropathology, studies have attempted to characterize the paradigms, stimuli, and signaling intermediates involved in stress-induced tau-P. Supporting an involvement of stress in AD are data demonstrating alterations in stress pathways and peptides in the AD brain and epidemiological data implicating stress exposure as a risk factor for AD. In this review, the question of whether stress-induced tau-P can be used as a model for examining the relationship between functional neuroplasticity and neuronal vulnerability will be discussed. PMID:19584431

  3. Spiral spectrum of Airy beams propagation through moderate-to-strong turbulence of maritime atmosphere.

    PubMed

    Zhu, Yun; Zhang, Yixin; Hu, Zhengda

    2016-05-16

    The spatial coherence radius in moderate-to-strong maritime turbulence is derived on the basis of the modified Rytov approximation. Models are developed to simulate the spiral spectrum of Airy beams propagating through moderate-to-strong maritime turbulence. In the moderate-to-strong irradiance fluctuation region, we analyze the effects of maritime turbulence on the spread of the spiral spectrum of Airy beams in a horizontal propagation path. Results indicate that the increment in the inner-scale significantly increases the received power. By contrast, the outer-scale elicits a negligible effect on the received power if the ratio of the inner-scale to the outer-scale is less than 0.01. The outer-scale affects the received power only if the ratio is greater than 0.01. The performance of a light source is essential for the received power of Airy beams carrying orbital angular momentum (OAM) through moderate-to-strong maritime turbulence. Airy beams with longer wavelengths, smaller OAM numbers, larger radii of the main ring, and smaller diameters of the circular aperture are less affected by maritime turbulence. Autofocusing of Airy beams is beneficial for the propagation of the spiral spectrum in a certain propagation distance. These results contribute to the design of optical communication systems with OAM encoding for moderate-to-strong maritime turbulence.

  4. Spiral spectrum of Airy beams propagation through moderate-to-strong turbulence of maritime atmosphere.

    PubMed

    Zhu, Yun; Zhang, Yixin; Hu, Zhengda

    2016-05-16

    The spatial coherence radius in moderate-to-strong maritime turbulence is derived on the basis of the modified Rytov approximation. Models are developed to simulate the spiral spectrum of Airy beams propagating through moderate-to-strong maritime turbulence. In the moderate-to-strong irradiance fluctuation region, we analyze the effects of maritime turbulence on the spread of the spiral spectrum of Airy beams in a horizontal propagation path. Results indicate that the increment in the inner-scale significantly increases the received power. By contrast, the outer-scale elicits a negligible effect on the received power if the ratio of the inner-scale to the outer-scale is less than 0.01. The outer-scale affects the received power only if the ratio is greater than 0.01. The performance of a light source is essential for the received power of Airy beams carrying orbital angular momentum (OAM) through moderate-to-strong maritime turbulence. Airy beams with longer wavelengths, smaller OAM numbers, larger radii of the main ring, and smaller diameters of the circular aperture are less affected by maritime turbulence. Autofocusing of Airy beams is beneficial for the propagation of the spiral spectrum in a certain propagation distance. These results contribute to the design of optical communication systems with OAM encoding for moderate-to-strong maritime turbulence. PMID:27409905

  5. Evolution of the ring Airy Gaussian beams with a spiral phase in the Kerr medium

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Chen, Chidao; Peng, Xi; Peng, Yulian; Zhou, Meiling; Deng, Dongmei; Guo, Hong

    2016-05-01

    Nonlinear optical phenomena are of great practical interest in optics. The evolution of ring Airy Gaussian beams with a spiral phase in the nonlinear Kerr medium is investigated using the nonlinear Schrödinger equation. Numerical simulations indicate that the distribution factor b can influence the formation of the ring Airy Gaussian beams. Results show that the beams can be oscillating, and the light filament can be achieved under appropriate laser input power. On the other hand, the evolution of the ring Airy Gaussian beams with a spiral phase in the nonlinear Kerr medium can be implemented, and the numerical simulations of the holographic generation of the ring Airy Gaussian vortex beams propagated in the medium demonstrate that the vortex can be preserved along the propagation. The Poynting vector shows that the energy flow of the ring Airy Gaussian beams flows in the opposite direction on both sides of the focus plane; however, for beams with a spiral phase, the flow direction remains the same; the energy flow can rotate in opposite directions on both sides of the focal plane.

  6. Regulation of the Adrenal Cortex Function During Stress

    NASA Technical Reports Server (NTRS)

    Soliman, K. F. A.

    1978-01-01

    A proposal to study the function of the adrenal gland in the rat during stress is presented. In the proposed project, three different phases of experimentation will be undertaken. The first phase includes establishment of the circadian rhythm of both brain amines and glucocoticoids, under normal conditions and under chronic and acute stressful conditions. The second phase includes the study of the pharmacokinetics of glucocorticoid binding under normal and stress conditions. The third phase includes brain uptake and binding under different experimental conditions. In the outlined experiments brain biogenic amines will be evaluated, adrenal functions will be measured and stress effect on those parameters will be studied. It is hoped that this investigation can explain some of the complex relationships between the brain neurotransmitter and adrenal function.

  7. Dynamic enhancement of autofocusing property for symmetric Airy beam with exponential amplitude modulation

    NASA Astrophysics Data System (ADS)

    Liu, Weiwei; Lu, Yao; Gong, Lei; Chu, Xiuxiang; Xue, Guosheng; Ren, Yuxuan; Zhong, Mincheng; Wang, Ziqiang; Zhou, Jinhua; Li, Yinmei

    2016-07-01

    A symmetric Airy beam (SAB) autofocuses during free space propagation. Such autofocusing SAB is useful in optical manipulation and biomedical imaging. However, its inherently limited autofocusing property may degrade the performance of the SAB in those applications. To enhance the autofocus, a symmetric apodization mask was proposed to regulate the SAB. In combination with the even cubic phase that shapes the SAB, this even exponential function mask with an adjustable parameter regulates the contribution of different frequency spectral components to the SAB. The propagation properties of this new amplitude modulated SAB (AMSAB) were investigated both theoretically and experimentally. Simulation shows that the energy distribution and autofocusing property of an AMSAB can be adjusted by the exponential amplitude modulation. Especially, the beam energy will be more concentrated in the central lobe once the even cubic phase is modulated by the mask with a higher proportion of high-frequency spectral components. Consequently, the autofocusing property and axial gradient force of AMSABs are efficiently enhanced. The experimental generation and characterization for AMSABs were implemented by modulating the collimated beam with a phase-only spatial light modulator. The experimental results well supported the theoretical predictions. With the ability to enhance the autofocus, the proposed exponential apodization modulation will make SAB more powerful in various applications, including optical trapping, fluorescence imaging and particle acceleration.

  8. Optical Bloch oscillations of an Airy beam in a photonic lattice with a linear transverse index gradient.

    PubMed

    Xiao, Fajun; Li, Baoran; Wang, Meirong; Zhu, Weiren; Zhang, Peng; Liu, Sheng; Premaratne, Malin; Zhao, Jianlin

    2014-09-22

    We theoretically report the existence of optical Bloch oscillations (BO) of an Airy beam in a one-dimensional optically induced photonic lattice with a linear transverse index gradient. The Airy beam experiencing optical BO shows a more robust non-diffracting feature than its counterparts in free space or in a uniform photonic lattice. Interestingly, a periodical recurrence of Airy shape accompanied with constant alternation of its acceleration direction is also found during the BO. Furthermore, we demonstrate that the period and amplitude of BO of an Airy beam can be readily controlled over a wide range by varying the index gradient and/or the lattice period. Exploiting these features, we propose a scheme to rout an Airy beam to a predefined output channel without losing its characteristics by longitudinally modulating the transverse index gradient.

  9. Optical Bloch oscillations and Zener tunneling of Airy beams in ionic-type photonic lattices.

    PubMed

    Xiao, Fajun; Zhu, Weiren; Shang, Wuyun; Wang, Meirong; Zhang, Peng; Liu, Sheng; Premaratne, Malin; Zhao, Jianlin

    2016-08-01

    We report on the existence of optical Bloch oscillations (OBOs) and Zener tunneling (ZT) of Airy beams in ionic-type photonic lattices with a refractive index ramp. Different from their counterparts in uniform lattices, Airy beams undergoing OBOs show an alternatively switched concave and convex trajectory as well as a periodical revival of input beam profiles. Moreover, the ionic-type photonic lattice established in photorefractive crystal exhibits a reconfigurable lattice structure, which provides a flexible way to tune the amplitude and period of the OBOs. Remarkably, it is demonstrated that the band gap of the lattice can be readily controlled by rotating the lattice inducing beam, which forces the ZT rate to follow two significant different decay curves amidst decreasing index gradient. Our results open up new possibilities for all-optical switching, routing and manipulation of Airy beams.

  10. Lossless Airy Surface Polaritons in a Metamaterial via Active Raman Gain

    PubMed Central

    Zhang, Qi; Tan, Chaohua; Huang, Guoxiang

    2016-01-01

    We propose a scheme to realize a lossless propagation of linear and nonlinear Airy surface polaritons (SPs) via active Raman gain (ARG). The system we suggest is a planar interface superposed by a negative index metamaterial (NIMM) and a dielectric, where three-level quantum emitters are doped. By using the ARG from the quantum emitters and the destructive interference effect between the electric and magnetic responses from the NIMM, we show that not only the Ohmic loss of the NIMM but also the light absorption of the quantum emitters can be completely eliminated. As a result, non-diffractive Airy SPs may propagate for very long distance without attenuation. We also show that the Kerr nonlinearity of the system can be largely enhanced due to the introduction of the quantum emitters and hence lossless Airy surface polaritonic solitons with very low power can be generated in the system. PMID:26891795

  11. [Personality and coping with stress in patients with functional dysphonia].

    PubMed

    Freidl, W; Egger, J; Friedrich, G

    1989-08-01

    The study was done to prove the etiopathogenetical power of some personality traits, proceeding life events, and strain effects when exposed to an experimental work-stress. 20 functional dysphonics, 14 individuals suffering from organic voice disorders and a group of 20 control persons were examined. The results show that the group of functional dysphonics produced a significant more positive self-evaluation regarding their personality with a clear tendency to restraint. Compared to the control group they showed a higher level of state anxiety in situations causing stress. Furthermore the influence of proceeding life events for the etiopathogenesis of functional dysphonia has become clear.

  12. Production of functional proteins: balance of shear stress and gravity

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas John (Inventor); Hammond, Timothy Grant (Inventor); Kaysen, James Howard (Inventor)

    2011-01-01

    A method for the production of functional proteins including hormones by renal cells in a three dimensional culturing process responsive to shear stress uses a rotating wall vessel. Natural mixture of renal cells expresses the enzyme 1-.alpha.-hydroxylase which can be used to generate the active form of vitamin D: 1,25-diOH vitamin D.sub.3. The fibroblast cultures and co-culture of renal cortical cells express the gene for erythropoietin and secrete erythropoietin into the culture supernatant. Other shear stress response genes are also modulated by shear stress, such as toxin receptors megalin and cubulin (gp280). Also provided is a method of treating an in-need individual with the functional proteins produced in a three dimensional co-culture process responsive to shear stress using a rotating wall vessel.

  13. Production of functional proteins: balance of shear stress and gravity

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas John (Inventor); Hammond, Timothy Grant (Inventor); Kaysen, James Howard (Inventor)

    2007-01-01

    The present invention provides a method for production of functional proteins including hormones by renal cells in a three dimensional co-culture process responsive to shear stress using a rotating wall vessel. Natural mixture of renal cells expresses the enzyme 1-a-hydroxylase which can be used to generate the active form of vitamin D: 1,25-diOH vitamin D3. The fibroblast cultures and co-culture of renal cortical cells express the gene for erythropoietin and secrete erythropoietin into the culture supernatant. Other shear stress response genes are also modulated by shear stress, such as toxin receptors megalin and cubulin (gp280). Also provided is a method of treating in-need individual with the functional proteins produced in a three dimensional co-culture process responsive to shear stress using a rotating wall vessel.

  14. Production of functional proteins: balance of shear stress and gravity

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas John (Inventor); Hammond, Timothy Grant (Inventor); Kaysen, James Howard (Inventor)

    2004-01-01

    The present invention provides a method for production of functional proteins including hormones by renal cells in a three dimensional co-culture process responsive to shear stress using a rotating wall vessel. Natural mixture of renal cells expresses the enzyme 1-a-hydroxylase which can be used to generate the active form of vitamin D: 1,25-diOH vitamin D3. The fibroblast cultures and co-culture of renal cortical cells express the gene for erythropoietin and secrete erythropoietin into the culture supernatant. Other shear stress response genes are also modulated by shear stress, such as toxin receptors megalin and cubulin (gp280). Also provided is a method of treating in-need individual with the functional proteins produced in a three dimensional co-culture process responsive to shear stress using a rotating wall vessel.

  15. Stability analysis of Reynolds stress response functional candidates

    NASA Astrophysics Data System (ADS)

    Dafinger, M.; Hallatschek, K.; Itoh, K.

    2013-04-01

    Complete information on the behavior of zonal flows in turbulence systems is coded in the turbulent stress response to the respective flow pattern. We show that turbulence stress response functionals containing only the linear first order wavenumber dependence on the flow pattern result in unstable structures up to the system size. A minimal augmentation to reproduce the flow patterns observed in turbulence simulations is discussed.

  16. Arrays of Gaussian vortex, Bessel and Airy beams by computer-generated hologram

    NASA Astrophysics Data System (ADS)

    Lu, Yang; Jiang, Bo; Lü, Shuchao; Liu, Yongqi; Li, Shasha; Cao, Zheng; Qi, Xinyuan

    2016-03-01

    We generate various kinds of arrays of Gaussian vortex, Bessel and Airy beams, respectively, with digital phase holograms (DPH) based on the fractional-Talbot effect by using the phase-only spatial light modulator (SLM). The linear and nonlinear transmissions of these beam arrays in strontium barium niobate (SBN) crystal are investigated numerically and experimentally. Compared with Gaussian vortex arrays, Bessel and Airy beam arrays can keep their patterns unchanged in over 20 mm, realizing non-diffracting transmission. The Fourier spectra (far-field diffraction patterns) of the lattices are also studied. The experimental results are in good agreement with the numerical simulations.

  17. Polyamines function in stress tolerance: from synthesis to regulation

    PubMed Central

    Liu, Ji-Hong; Wang, Wei; Wu, Hao; Gong, Xiaoqing; Moriguchi, Takaya

    2015-01-01

    Plants are challenged by a variety of biotic or abiotic stresses, which can affect their growth and development, productivity, and geographic distribution. In order to survive adverse environmental conditions, plants have evolved various adaptive strategies, among which is the accumulation of metabolites that play protective roles. A well-established example of the metabolites that are involved in stress responses, or stress tolerance, is the low-molecular-weight aliphatic polyamines, including putrescine, spermidine, and spermine. The critical role of polyamines in stress tolerance is suggested by several lines of evidence: firstly, the transcript levels of polyamine biosynthetic genes, as well as the activities of the corresponding enzymes, are induced by stresses; secondly, elevation of endogenous polyamine levels by exogenous supply of polyamines, or overexpression of polyamine biosynthetic genes, results in enhanced stress tolerance; and thirdly, a reduction of endogenous polyamines is accompanied by compromised stress tolerance. A number of studies have demonstrated that polyamines function in stress tolerance largely by modulating the homeostasis of reactive oxygen species (ROS) due to their direct, or indirect, roles in regulating antioxidant systems or suppressing ROS production. The transcriptional regulation of polyamine synthesis by transcription factors is also reviewed here. Meanwhile, future perspectives on polyamine research are also suggested. PMID:26528300

  18. Cytokines and macrophage function in humans - role of stress

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, Gerald (Principal Investigator)

    1996-01-01

    We have begun this study to commence the determination of the role of mild chronic stress in the effects of space flight on macrophage/monocyte function, a component of the immune response. Medical students undergoing regular periods of stress and relaxation have been shown to be an excellent model for determining the effects of stress on immune responses. We have begun using this model using the macrophage/monocyte as model leukocyte. The monocyte/macrophage plays a central role in immunoregulation. The studies to be included in this three year project are the effects of stress on: (1) interactions of monocytes with microbes, (2) monocyte production of cytokines, (3) monocyte phagocytosis and activity, and (4) monocyte expression of cell surface antigens important in immune responses. Stress hormone levels will also be carried out to determine if there is a correlation between stress effects on immune responses and hormonal levels. Psychological testing to insure subjects are actually stressed or relaxed at the time of testing will also be carried out. The results obtained from the proposed studies should be comparable with space flight studies with whole animals and isolated cell cultures. When complete this study should allow the commencement of the establishment of the role of stress as one compartment of the induction of immune alterations by space flight.

  19. Effects of heat stress on baroreflex function in humans

    NASA Technical Reports Server (NTRS)

    Crandall, Craig G.; Cui, Jian; Wilson, Thad E.

    2003-01-01

    INTRODUCTION: Heat stress significantly reduces orthostatic tolerance in humans. The mechanism(s) causing this response remain unknown. The purpose of this review article is to present data pertaining to the hypothesis that reduced orthostatic tolerance in heat stressed individuals is a result of heat stress induced alterations in baroflex function. METHODS: In both normothermic and heat stressed conditions baroreflex responsiveness was assessed via pharmacological and non-pharmacological methods. In addition, the effects of heat stress on post-synaptic vasoconstrictor responsiveness were assessed. RESULTS: Generally, whole body heating did not alter baroreflex sensitivity defined as the gain of the linear portion of the baroreflex curve around the operating point. However, whole body heating shifted the baroreflex curve to the prevailing (i.e. elevated) heart rate and muscle sympathetic nerve activity. Finally, the heat stress impaired vasoconstrictor responses to exogenous administration of adrenergic agonists. CONCLUSION: Current data do not support the hypothesis that reduced orthostatic tolerance associated with heat stress in humans is due to impaired baroreflex responsiveness. This phenomenon may be partially due to the effects of heat stress on reducing vasoconstrictor responsiveness.

  20. Using hyperbranched oligomer functionalized glass fillers to reduce shrinkage stress

    PubMed Central

    Ye, Sheng; Azarnoush, Setareh; Smith, Ian R.; Cramer, Neil B.; Stansbury, Jeffrey W.; Bowman, Christopher N

    2012-01-01

    Objective Fillers are widely utilized to enhance the mechanical properties of polymer resins. However, polymerization stress has the potential to increase due to the higher elastic modulus achieved upon filler addition. Here, we demonstrate a hyperbranched oligomer functionalized glass filler UV curable resin composite which is able to reduce the shrinkage stress without sacrificing mechanical properties. Methods A 16-functional alkene-terminated hyperbranched oligomer is synthesized by thiol-acrylate and thiol-yne reactions and the product structure is analyzed by 1H-NMR, mass spectroscopy, and gel permeation chromatography. Surface functionalization of the glass filler is measured by thermogravimetric analysis. Reaction kinetics, mechanical properties and shrinkage stress are studied via Fourier transform infrared spectroscopy, dynamic mechanical analysis and a tensometer, respectively. Results Silica nanoparticles are functionalized with a flexible 16-functional alkene-terminated hyperbranched oligomer which is synthesized by multistage thiol-ene/yne reactions. 93% of the particle surface was covered by this oligomer and an interfacial layer ranging from 0.7 – 4.5 nm thickness is generated. A composite system with these functionalized silica nanoparticles incorporated into the thiol-yne-methacrylate resin demonstrates 30% reduction of shrinkage stress (from 0.9 MPa to 0.6 MPa) without sacrificing the modulus (3100 ± 300 MPa) or glass transition temperature (62 ± 3 °C). Moreover, the shrinkage stress of the composite system builds up at much later stages of the polymerization as compared to the control system. Significance Due to the capability of reducing shrinkage stress without sacrificing mechanical properties, this composite system will be a great candidate for dental composite applications. PMID:22717296

  1. Learning Under Stress: The Inverted-U-Shape Function Revisited

    ERIC Educational Resources Information Center

    Salehi, Basira; Cordero, M. Isabel; Sandi, Carmen

    2010-01-01

    Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze…

  2. Wheat EST resources for functional genomics of abiotic stress

    PubMed Central

    Houde, Mario; Belcaid, Mahdi; Ouellet, François; Danyluk, Jean; Monroy, Antonio F; Dryanova, Ani; Gulick, Patrick; Bergeron, Anne; Laroche, André; Links, Matthew G; MacCarthy, Luke; Crosby, William L; Sarhan, Fathey

    2006-01-01

    Background Wheat is an excellent species to study freezing tolerance and other abiotic stresses. However, the sequence of the wheat genome has not been completely characterized due to its complexity and large size. To circumvent this obstacle and identify genes involved in cold acclimation and associated stresses, a large scale EST sequencing approach was undertaken by the Functional Genomics of Abiotic Stress (FGAS) project. Results We generated 73,521 quality-filtered ESTs from eleven cDNA libraries constructed from wheat plants exposed to various abiotic stresses and at different developmental stages. In addition, 196,041 ESTs for which tracefiles were available from the National Science Foundation wheat EST sequencing program and DuPont were also quality-filtered and used in the analysis. Clustering of the combined ESTs with d2_cluster and TGICL yielded a few large clusters containing several thousand ESTs that were refractory to routine clustering techniques. To resolve this problem, the sequence proximity and "bridges" were identified by an e-value distance graph to manually break clusters into smaller groups. Assembly of the resolved ESTs generated a 75,488 unique sequence set (31,580 contigs and 43,908 singletons/singlets). Digital expression analyses indicated that the FGAS dataset is enriched in stress-regulated genes compared to the other public datasets. Over 43% of the unique sequence set was annotated and classified into functional categories according to Gene Ontology. Conclusion We have annotated 29,556 different sequences, an almost 5-fold increase in annotated sequences compared to the available wheat public databases. Digital expression analysis combined with gene annotation helped in the identification of several pathways associated with abiotic stress. The genomic resources and knowledge developed by this project will contribute to a better understanding of the different mechanisms that govern stress tolerance in wheat and other cereals. PMID

  3. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions

    PubMed Central

    Baert, Jan M.; Janssen, Colin R.; Sabbe, Koen; De Laender, Frederik

    2016-01-01

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity–ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity–productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity–productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions. PMID:27534986

  4. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.

    PubMed

    Baert, Jan M; Janssen, Colin R; Sabbe, Koen; De Laender, Frederik

    2016-01-01

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions. PMID:27534986

  5. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.

    PubMed

    Baert, Jan M; Janssen, Colin R; Sabbe, Koen; De Laender, Frederik

    2016-08-18

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions.

  6. Resistance of functional Lactobacillus plantarum strains against food stress conditions.

    PubMed

    Ferrando, Verónica; Quiberoni, Andrea; Reinhemer, Jorge; Suárez, Viviana

    2015-06-01

    The survival of three Lactobacillus plantarum strains (Lp 790, Lp 813 and Lp 998) with functional properties was studied taking into account their resistance to thermal, osmotic and oxidative stress factors. Stress treatments applied were: 52 °C-15 min (Phosphate Buffer pH 7, thermal shock), H2O2 0.1% (p/v) - 30 min (oxidative shock) and NaCl aqueous solution at 17, 25 and 30% (p/v) (room temperature - 1 h, osmotic shock). The osmotic stress was also evaluated on cell growth in MRS broth added of 2, 4, 6, 8 and 10% (p/v) of NaCl, during 20 h at 30 °C. The cell thermal adaptation was performed in MRS broth, selecting 45 °C for 30 min as final conditions for all strains. Two strains (Lp 813 and Lp 998) showed, in general, similar behaviour against the three stress factors, being clearly more resistant than Lp 790. An evident difference in growth kinetics in presence of NaCl was observed between Lp 998 and Lp 813, Lp998 showing a higher optical density (OD570nm) than Lp 813 at the end of the assay. Selected thermal adaptation improved by 2 log orders the thermal resistance of both strains, but cell growth in presence of NaCl was enhanced only in Lp 813. Oxidative resistance was not affected with this thermal pre-treatment. These results demonstrate the relevance of cell technological resistance when selecting presumptive "probiotic" cultures, since different stress factors might considerably affect viability or/and performance of the strains. The incidence of stress conditions on functional properties of the strains used in this work are currently under research in our group.

  7. Prenatal maternal stress exposure and immune function in the offspring.

    PubMed

    Veru, Franz; Laplante, David P; Luheshi, Giamal; King, Suzanne

    2014-03-01

    The intra-uterine environment provides the first regulatory connection for the developing fetus and shapes its physiological responses in preparation for postnatal life. Psychological stress acts as a programming determinant by setting functional parameters to abnormal levels, thus inducing postnatal maladaptation. The effects of prenatal maternal stress (PNMS) on the developing immune system have been documented mostly through animal studies, but inconsistent results and methodological differences have hampered the complete understanding of these findings. As the immune system follows a similar ontogenic pattern in all mammals, a translational framework based on the developmental windows of vulnerability proposed by immunotoxicology studies was created to integrate these findings. The objective of this review is to examine the available literature on PNMS and immune function in the offspring through the above framework and gain a better understanding of these results by elucidating the moderating influence of the stressor type, timing and duration, and the offspring species, sex and age at assessment. The evaluation of the literature through this framework showed that the effects of PNMS are parameter specific: the moderating effects of timing in gestation were relevant for lymphocyte population numbers, Natural Killer cell function and mitogen-induced proliferation. The presence of an important and directional sexual dimorphism was evident and the influence of the type or duration of PNMS paralleled that of stress in non-pregnant animals. In conclusion, PNMS is a relevant factor in the programming of immune function. Its consequences may be related to disorders with an important immune component such as allergies.

  8. Posttraumatic stress symptom clusters associations with psychopathology and functional impairment.

    PubMed

    Heir, Trond; Piatigorsky, Auran; Weisæth, Lars

    2010-12-01

    We examined posttraumatic stress symptom clusters associations with psychopathology and functional impairment in 899 Norwegian survivors of the 2004 South-East Asia tsunami six months post-disaster. Posttraumatic stress symptoms were assessed with the Impact of Event Scale-Revised (IES-R) with intrusion, avoidance, and hyper-arousal subscales. For criterion variables, we used 10 indicators of psychopathology and functional impairment, e.g. having mental health problems, seeing mental health professionals, and use of medication or sick leave. Hyper-arousal had stronger correlations than avoidance with all criterion variables (p values<0.001) and stronger correlations than intrusion with seven of the 10 criterion variables (p values<0.01). Also, intrusion had stronger correlations than avoidance with seven of 10 criterion variables (p values<0.05). Thus, our findings indicate that symptoms of hyper-arousal may be more closely linked to psychopathology and functional impairment than other symptoms of posttraumatic stress following a sudden onset, short duration, natural disaster event.

  9. Initial community evenness favours functionality under selective stress.

    PubMed

    Wittebolle, Lieven; Marzorati, Massimo; Clement, Lieven; Balloi, Annalisa; Daffonchio, Daniele; Heylen, Kim; De Vos, Paul; Verstraete, Willy; Boon, Nico

    2009-04-01

    Owing to the present global biodiversity crisis, the biodiversity-stability relationship and the effect of biodiversity on ecosystem functioning have become major topics in ecology. Biodiversity is a complex term that includes taxonomic, functional, spatial and temporal aspects of organismic diversity, with species richness (the number of species) and evenness (the relative abundance of species) considered among the most important measures. With few exceptions (see, for example, ref. 6), the majority of studies of biodiversity-functioning and biodiversity-stability theory have predominantly examined richness. Here we show, using microbial microcosms, that initial community evenness is a key factor in preserving the functional stability of an ecosystem. Using experimental manipulations of both richness and initial evenness in microcosms with denitrifying bacterial communities, we found that the stability of the net ecosystem denitrification in the face of salinity stress was strongly influenced by the initial evenness of the community. Therefore, when communities are highly uneven, or there is extreme dominance by one or a few species, their functioning is less resistant to environmental stress. Further unravelling how evenness influences ecosystem processes in natural and humanized environments constitutes a major future conceptual challenge.

  10. Functional impairment, stress, and psychosocial intervention in bipolar disorder.

    PubMed

    Miklowitz, David J

    2011-12-01

    The longitudinal course of bipolar disorder (BD) is highly impairing. This article reviews recent research on functional impairment in the course of BD, the roles of social and intrafamilial stress in relapse and recovery, and the role of adjunctive psychosocial interventions in reducing risk and enhancing functioning. Comparative findings in adult and childhood BD are highlighted. Life events and family-expressed emotion have emerged as significant predictors of the course of BD. Studies of social information processing suggest that impairments in the recognition of facial emotions may characterize both adult- and early-onset bipolar patients. Newly developed psychosocial interventions, particularly those that focus on family and social relationships, are associated with more rapid recovery from episodes and better psychosocial functioning. Family-based psychoeducational approaches are promising as early interventions for children with BD or children at risk of developing the disorder. For adults, interpersonal therapy, mindfulness-based strategies, and cognitive remediation may offer promise in enhancing functioning.

  11. Learning under stress: the inverted-U-shape function revisited.

    PubMed

    Salehi, Basira; Cordero, M Isabel; Sandi, Carmen

    2010-10-01

    Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze (RAWM). Variations in stress intensity were induced using different water temperatures (25°C, 19°C, and 16°C), which elicited increased plasma corticosterone levels. During spatial training over three consecutive days, an inverted-U shape was found, with animals trained at 19°C making fewer errors than animals trained at either higher (16°C) or lower (25°C) stress conditions. Interestingly, this function was already observed by the last trial of day 1 and maintained on the first day trial of day 2. A long-term recall probe test administered under equal temperature conditions (20°C) revealed differences in performance according to the animals' former training conditions; i.e., platform searching for rats trained at 25°C was less accurate than for rats trained at either 16°C or 19°C. In reversal learning, groups trained at both 19°C and 25°C showed better performance than the 16°C group. We also found an interaction between anxiety and exploration traits on how individuals were affected by stressors during spatial learning. In summary, our findings confirm, for the first time, the existence of an inverted-U-shape memory function according to stressor intensity during the early learning and memory phases in a hippocampus-dependent task, and indicate the existence of individual differences related to personality-like profiles for performance at either high or low stress conditions.

  12. Renal Function and Cardiovascular Response to Mental Stress

    PubMed Central

    Seliger, Stephen L.; Katzel, Leslie I.; Fink, Jeffrey C.; Weir, Matthew R.; Waldstein, Shari R.

    2008-01-01

    Background/Aims Cardiovascular reactivity (CVR), defined as an exaggerated hemodynamic response to mental stress, is a putative vascular risk factor and may reflect sympathetic hyperactivity. Chronic kidney disease (CKD) is also associated with sympathetic hyperactivity and vascular risk, but its relationship with CVR is unknown. Methods CVR was assessed in 107 individuals without overt cardiovascular disease or diabetes. Blood pressure and heart rate responses were elicited by three experimental tasks designed to evoke mental stress. Glomerular filtration rate (eGFR) was estimated using the MDRD formula. General linear models estimated the association between renal function and CVR, adjusting for potential confounders. Results Mean age was 66 years and 11% had eGFR of <60 ml/min/1.73 m2. After multivariate adjustment, a low eGFR was associated with a greater stress response of systolic blood pressure, heart rate, and pulse pressure. Associations were only partially attenuated after adjustment for lipids and glucose tolerance. When considered as a continuous variable, lower eGFR was associated with a greater blood pressure response after adjustment for glycemia. Conclusion Although there were relatively few participants with CKD, these results suggest a relationship between CKD and greater CVR. Further investigation is warranted into factors that mediate this relationship and potential clinical consequences of this exaggerated response to stress in CKD. PMID:18025779

  13. A micromechanical study of residual stresses in functionally graded materials

    SciTech Connect

    Dao, M.; Gu, P.; Maewal, A.; Asaro, R.J.

    1997-08-01

    A physically based computational micromechanics model is developed to study random and discrete microstructures in functionally graded materials (FGMs). The influences of discrete microstructure on residual stress distributions at grain size level are examined with respect to material gradient and FGM volume percentage (within a ceramic-FGM-metal three-layer structure). Both thermoelastic and thermoplastic deformation are considered, and the plastic behavior of metal grains is modeled at the single crystal level using crystal plasticity theory. The results are compared with those obtained using a continuous model which does not consider the microstructural randomness and discreteness. In an averaged sense both the micromechanics model and the continuous model give practically the same macroscopic stresses; whereas the discrete micromechanics model predicts fairly high residual stress concentrations at the grain size level (i.e., higher than 700 MPa in 5--6 vol% FGM grains) with only a 300 C temperature drop in a Ni-Al{sub 2}O{sub 3} FGM system. Statistical analysis shows that the residual stress concentrations are insensitive to material gradient and FGM volume percentage. The need to consider microstructural details in FGM microstructures is evident. The results obtained provide some insights for improving the reliability of FGMs against fracture and delamination.

  14. Caloric intake, stress, and menstrual function in athletes.

    PubMed

    Schweiger, U; Laessle, R; Schweiger, M; Herrmann, F; Riedel, W; Pirke, K M

    1988-03-01

    The cause of menstrual disturbance in athletes is still debated. Apart from the acute and chronic effects of exertion, other associated behavioral variables are suspected to play a key role. A longitudinal study with frequent blood sampling was undertaken to link information about nutrition and stress with a quantitative assessment of endocrine menstrual function in 18 endurance-trained athletes and 25 age-matched, nonathletic women. Four athletes did not show hormonal signs of follicular development. The 14 athletes with cyclic gonadal function did not differ from controls with regard to estradiol concentrations during the follicular phase and at midcycle. During the luteal phase, however, they showed significantly reduced areas under the estradiol and progesterone curves. Caloric intake, as assessed by nutritional diaries, correlated positively with the area under the progesterone curve during the luteal phase (rs = 0.70, P less than 0.01). Ratings of subjective stress in the area "partner, family, friends" correlated negatively with the luteal progesterone area (rs = 0.80; P less than 0.01). Data support the hypothesis that nutrition and stress may play a critical role in the genesis of menstrual disturbance in athletes.

  15. Nonlinear plasma-assisted collapse of ring-Airy wave packets

    NASA Astrophysics Data System (ADS)

    Panagiotopoulos, Paris; Couairon, Arnaud; Kolesik, Miroslav; Papazoglou, Dimitris G.; Moloney, Jerome V.; Tzortzakis, Stelios

    2016-03-01

    We numerically demonstrate that femtosecond ring-Airy wave packets are able to overcome the reference intensity clamping of 4 ×1013 W/cm2 for filaments generated with Gaussian beams at low numerical apertures and form an intense sharp intensity peak on axis. Numerical simulations, with unidirectional propagation models for the pulse envelope and the carrier resolved electric field, reveal that the driving mechanism for this unexpected intensity increase is due to the self-generated plasma. The plasma formation, in conjunction with the circular geometry of the beam, force the wave packet into a multistage collapse process which takes place faster than the saturating mechanisms can compensate. We report here a nonstandard mechanism that increases the intensity of a collapsing wave packet, due to the joint contributions of the cubic phase of the Airy beam and the formation of a partially reflecting plasma.

  16. Wavelength estimation by using the Airy disk from a diffraction pattern with didactic purposes

    NASA Astrophysics Data System (ADS)

    Rivera-Ortega, Uriel; Pico-Gonzalez, Beatriz

    2016-01-01

    In this paper a simple and easy to implement method that uses the Airy disk generated from a Fraunhofer diffraction pattern due to a circular aperture will be used to estimate the wavelength of the illuminating laser source. This estimation is based on the measurement of the Airy disk diameter, whose approximation is directly proportional to the wavelength of the light source and to the distance between the aperture and the image plane; and inversely proportional to the diameter of the aperture. Due to the characteristics and versatility of the present proposal, this is perfectly suitable for use in graduate or undergraduate physics laboratories, or even in classrooms for educational and/or demonstrative purposes.

  17. A compact Airy beam light sheet microscope with a tilted cylindrical lens.

    PubMed

    Yang, Zhengyi; Prokopas, Martynas; Nylk, Jonathan; Coll-Lladó, Clara; Gunn-Moore, Frank J; Ferrier, David E K; Vettenburg, Tom; Dholakia, Kishan

    2014-10-01

    Light-sheet imaging is rapidly gaining importance for imaging intact biological specimens. Many of the latest innovations rely on the propagation-invariant Bessel or Airy beams to form an extended light sheet to provide high resolution across a large field of view. Shaping light to realize propagation-invariant beams often relies on complex programming of spatial light modulators or specialized, custom made, optical elements. Here we present a straightforward and low-cost modification to the traditional light-sheet setup, based on the open-access light-sheet microscope OpenSPIM, to achieve Airy light-sheet illumination. This brings wide field single-photon light-sheet imaging to a broader range of endusers. Fluorescent microspheres embedded in agarose and a zebrafish larva were imaged to demonstrate how such a microscope can have a minimal footprint and cost without compromising on imaging quality.

  18. Nonlinear dynamics of Airy-vortex 3D wave packets: emission of vortex light waves.

    PubMed

    Driben, Rodislav; Meier, Torsten

    2014-10-01

    The dynamics of 3D Airy-vortex wave packets is studied under the action of strong self-focusing Kerr nonlinearity. Emissions of nonlinear 3D waves out of the main wave packets with the topological charges were demonstrated. Because of the conservation of the total angular momentum, charges of the emitted waves are equal to those carried by the parental light structure. The rapid collapse imposes a severe limitation on the propagation of multidimensional waves in Kerr media. However, the structure of the Airy beam carrier allows the coupling of light from the leading, most intense peak into neighboring peaks and consequently strongly postpones the collapse. The dependence of the critical input amplitude for the appearance of a fast collapse on the beam width is studied for wave packets with zero and nonzero topological charges. Wave packets carrying angular momentum are found to be much more resistant to the rapid collapse.

  19. Dynamics of Finite Energy Airy Beams Carrying Orbital Angular Momentum in Multilevel Atomic Vapors

    NASA Astrophysics Data System (ADS)

    Wu, Zhenkun; Wang, Shun; Hu, Weifei; Gu, Yuzong

    2016-10-01

    We numerically investigate the dynamics of inward circular finite-energy Airy beams carrying different orbital angular momentum (OAM) numbers in a close-Λ three-level atomic vapor with the electromagnetically induced transparency (EIT) window. We report that due to the EIT induced by the microwave field, the transverse intensity distribution properties of Airy beam can be feasibly manipulated and modulated through adjusting OAM numbers l and the frequency detuning, as well as the propagation distance, in the multi-level atomic systems. What's more, the rotation of the beam also can be observed with different positions in atomic ensembles. The investigation may provide a useful tool for studying particle manipulation, signal processing and propagation in graded-index (GRIN) fibers.

  20. A compact Airy beam light sheet microscope with a tilted cylindrical lens

    PubMed Central

    Yang, Zhengyi; Prokopas, Martynas; Nylk, Jonathan; Coll-Lladó, Clara; Gunn-Moore, Frank J.; Ferrier, David E. K.; Vettenburg, Tom; Dholakia, Kishan

    2014-01-01

    Light-sheet imaging is rapidly gaining importance for imaging intact biological specimens. Many of the latest innovations rely on the propagation-invariant Bessel or Airy beams to form an extended light sheet to provide high resolution across a large field of view. Shaping light to realize propagation-invariant beams often relies on complex programming of spatial light modulators or specialized, custom made, optical elements. Here we present a straightforward and low-cost modification to the traditional light-sheet setup, based on the open-access light-sheet microscope OpenSPIM, to achieve Airy light-sheet illumination. This brings wide field single-photon light-sheet imaging to a broader range of endusers. Fluorescent microspheres embedded in agarose and a zebrafish larva were imaged to demonstrate how such a microscope can have a minimal footprint and cost without compromising on imaging quality. PMID:25360362

  1. A compact Airy beam light sheet microscope with a tilted cylindrical lens.

    PubMed

    Yang, Zhengyi; Prokopas, Martynas; Nylk, Jonathan; Coll-Lladó, Clara; Gunn-Moore, Frank J; Ferrier, David E K; Vettenburg, Tom; Dholakia, Kishan

    2014-10-01

    Light-sheet imaging is rapidly gaining importance for imaging intact biological specimens. Many of the latest innovations rely on the propagation-invariant Bessel or Airy beams to form an extended light sheet to provide high resolution across a large field of view. Shaping light to realize propagation-invariant beams often relies on complex programming of spatial light modulators or specialized, custom made, optical elements. Here we present a straightforward and low-cost modification to the traditional light-sheet setup, based on the open-access light-sheet microscope OpenSPIM, to achieve Airy light-sheet illumination. This brings wide field single-photon light-sheet imaging to a broader range of endusers. Fluorescent microspheres embedded in agarose and a zebrafish larva were imaged to demonstrate how such a microscope can have a minimal footprint and cost without compromising on imaging quality. PMID:25360362

  2. Combined thermal and herbicide stress in functionally diverse coral symbionts.

    PubMed

    van Dam, J W; Uthicke, S; Beltran, V H; Mueller, J F; Negri, A P

    2015-09-01

    Most reef building corals rely on symbiotic microalgae (genus Symbiodinium) to supply a substantial proportion of their energy requirements. Functional diversity of different Symbiodinium genotypes, endorsing the host with physiological advantages, has been widely reported. Yet, the influence of genotypic specificity on the symbiont's susceptibility to contaminants or cumulative stressors is unknown. Cultured Symbiodinium of presumed thermal-tolerant clade D tested especially vulnerable to the widespread herbicide diuron, suggesting important free-living populations may be at risk in areas subjected to terrestrial runoff. Co-exposure experiments where cultured Symbiodinium were exposed to diuron over a thermal stress gradient demonstrated how fast-growing clade C1 better maintained photosynthetic capability than clade D. The mixture toxicity model of Independent Action, considering combined thermal stress and herbicide contamination, revealed response additivity for inhibition of photosynthetic yield in both tested cultures, emphasizing the need to account for cumulative stressor impacts in ecological risk assessment and resource management. PMID:25989453

  3. Can Hooke's Law and the Airy Disk First Zero Radius Formulation Predict That Education and Work Environment Visual Task Excesses Lead to Vision Impairment?

    NASA Astrophysics Data System (ADS)

    McLeod, Douglas M.; McLeod, Roger D.

    2002-10-01

    DMM found that a distant, single church steeple, which appeared "twin-like" after extended studying episodes, could then be brought into correct visual register by a conscious effort. Similar anecdotal events are repeatable by attentive students or workers in the early stages of educationally or work environmentally induced repetitive vision impairment. RDM proposes that his model for vision and its repair utilizes sequentially applied vision improvement stages that are the equivalent of DMM's experience. Such visual events involve feedback signals generated during the crystalline lens's minor dioptric oscillations that are generated by the blinking reflex, empowered by the Airy radius proportional to wavelength times focal length divided by pupil aperture. This implies some conscious control of feedback mechanisms, which can self-regulate vision protecting processes. Continued visual effort under duress invokes Hooke's "stress proportional to strain." Exceeding extrinsic eye muscles' elastic limits overrides spontaneous feedback repair mechanisms.

  4. Shaping symmetric Airy beam through binary amplitude modulation for ultralong needle focus

    SciTech Connect

    Fang, Zhao-Xiang; Gong, Lei; Ren, Yu-Xuan; Vaveliuk, Pablo; Chen, Yue; Lu, Rong-De

    2015-11-28

    Needle-like electromagnetic field has various advantages for the applications in high-resolution imaging, Raman spectroscopy, as well as long-distance optical transportation. The realization of such field often requires high numerical aperture (NA) objective lens and the transmission masks. We demonstrate an ultralong needle-like focus in the optical range produced with an ordinary lens. This is achieved by focusing a symmetric Airy beam (SAB) generated via binary spectral modulation with a digital micromirror device. Such amplitude modulation technique is able to shape traditional Airy beams, SABs, as well as the dynamic transition modes between the one-dimensional and two-dimensional (2D) symmetric Airy modes. The created 2D SAB was characterized through measurement of the propagating fields with one of the four main lobes blocked by an opaque mask. The 2D SAB was verified to exhibit self-healing property against propagation with the obstructed major lobe reconstructed after a certain distance. We further produced an elongated focal line by concentrating the SAB via lenses with different NAs and achieved an ultralong longitudinal needle focus. The produced long needle focus will be applied in optical, chemical, and biological sciences.

  5. Analytical Model for Thermal Elastoplastic Stresses of Functionally Graded Materials

    SciTech Connect

    Zhai, P. C.; Chen, G.; Liu, L. S.; Fang, C.; Zhang, Q. J.

    2008-02-15

    A modification analytical model is presented for the thermal elastoplastic stresses of functionally graded materials subjected to thermal loading. The presented model follows the analytical scheme presented by Y. L. Shen and S. Suresh [6]. In the present model, the functionally graded materials are considered as multilayered materials. Each layer consists of metal and ceramic with different volume fraction. The ceramic layer and the FGM interlayers are considered as elastic brittle materials. The metal layer is considered as elastic-perfectly plastic ductile materials. Closed-form solutions for different characteristic temperature for thermal loading are presented as a function of the structure geometries and the thermomechanical properties of the materials. A main advance of the present model is that the possibility of the initial and spread of plasticity from the two sides of the ductile layers taken into account. Comparing the analytical results with the results from the finite element analysis, the thermal stresses and deformation from the present model are in good agreement with the numerical ones.

  6. Stress Recovery and Dynamic Analysis of Functionally Graded Materials

    NASA Astrophysics Data System (ADS)

    Paulino, Rivânia H.; Romero, Juan S.; Menandro, Fernando C. M.

    2008-02-01

    A macroelement recovery technique for the strain field of a functionally graded material (FGM), based on the residual dynamic equilibrium equation for elasticity, is proposed. The derivatives are recovered by solving a local variational problem, using the superconvergence points. The basic idea is to utilize post-processing to achieve a more accurate approximation of the stresses while considering the dynamic nature of the problem. The development includes dynamic modeling of FGM and can be applied to direct and inverse problems. A numerical simulation is presented to better demonstrate the proposed methodology.

  7. Shear-stress relaxation and ensemble transformation of shear-stress autocorrelation functions.

    PubMed

    Wittmer, J P; Xu, H; Baschnagel, J

    2015-02-01

    We revisit the relation between the shear-stress relaxation modulus G(t), computed at finite shear strain 0<γ≪1, and the shear-stress autocorrelation functions C(t)|(γ) and C(t)|(τ) computed, respectively, at imposed strain γ and mean stress τ. Focusing on permanent isotropic spring networks it is shown theoretically and computationally that in general G(t)=C(t)|(τ)=C(t)|(γ)+G(eq) for t>0 with G(eq) being the static equilibrium shear modulus. G(t) and C(t)|(γ) thus must become different for solids and it is impossible to obtain G(eq) alone from C(t)|(γ) as often assumed. We comment briefly on self-assembled transient networks where G(eq)(f) must vanish for a finite scission-recombination frequency f. We argue that G(t)=C(t)|(τ)=C(t)|(γ) should reveal an intermediate plateau set by the shear modulus G(eq)(f=0) of the quenched network.

  8. Epigenetic and immune function profiles associated with posttraumatic stress disorder

    PubMed Central

    Uddin, Monica; Aiello, Allison E.; Wildman, Derek E.; Koenen, Karestan C.; Pawelec, Graham; de los Santos, Regina; Goldmann, Emily; Galea, Sandro

    2010-01-01

    The biologic underpinnings of posttraumatic stress disorder (PTSD) have not been fully elucidated. Previous work suggests that alterations in the immune system are characteristic of the disorder. Identifying the biologic mechanisms by which such alterations occur could provide fundamental insights into the etiology and treatment of PTSD. Here we identify specific epigenetic profiles underlying immune system changes associated with PTSD. Using blood samples (n = 100) obtained from an ongoing, prospective epidemiologic study in Detroit, the Detroit Neighborhood Health Study, we applied methylation microarrays to assay CpG sites from more than 14,000 genes among 23 PTSD-affected and 77 PTSD-unaffected individuals. We show that immune system functions are significantly overrepresented among the annotations associated with genes uniquely unmethylated among those with PTSD. We further demonstrate that genes whose methylation levels are significantly and negatively correlated with traumatic burden show a similar strong signal of immune function among the PTSD affected. The observed epigenetic variability in immune function by PTSD is corroborated using an independent biologic marker of immune response to infection, CMV—a typically latent herpesvirus whose activity was significantly higher among those with PTSD. This report of peripheral epigenomic and CMV profiles associated with mental illness suggests a biologic model of PTSD etiology in which an externally experienced traumatic event induces downstream alterations in immune function by reducing methylation levels of immune-related genes. PMID:20439746

  9. On the Function and Use of Stress in Discourse.

    ERIC Educational Resources Information Center

    Lehman, Christina

    A telephone conversation was transcribed and marked for stress. A portion of the transcription, not marked for stress, was given to native English speakers who were asked to underline the word(s) in each sentence or phrase that should receive the most prominent stress. The overlap of actual stress and the assignments of the participants who were…

  10. Anxiety, stress, depression, and psychosocial functioning of Indian adolescents

    PubMed Central

    Singh, Kamlesh; Junnarkar, Mohita; Sharma, Soumya

    2015-01-01

    Background: Lifetime prevalence of depression and anxiety increases from 1% of the population under age 12 years to ~17%-25% of the population by the end of adolescence. The greatest increase in new cases occurs between 15-18 years. Indian empirical studies have reported a prevalence of psychiatric morbidity in the range between 14.4% and 31.7%; thus, affecting psychosocial functioning. Aims: The objectives of the current study were to (i) examine the psychometric properties of the DASS and SDQ on Indian adolescents, (ii) explore the role of socio- demographic variablesand (iii) examine if there was any difference between school going and school dropouts. Methodology: Data from 1812 students, aged 12-19 years was collected with mean age = 15.67 years (SD =1.41 years). The participants were administered a booklet containing demographic questionnaire and psychometric scales such as DASS-21 (Henry & Crawford, 2005; Lovibond & Lovibond, 1999) and Strengths and Difficulties Questionnaire (Goodman, 1997). Statistical Analysis: Structure validation, correlational analysis and multivariate analysis. Results and Conclusions: The results of validation indicated that English and Hindi version of 3 factor model of DASS and 2 factor model of SDQ was an acceptable model fit. It was noted that early adolescents were high on prosocial behaviour whereas late adolescents were high on difficulties score. Females were higher than males on prosocial behaviour. Adolescents residing in rural areas differed from their urban counterparts on prosocial behaviour and anxiety. Government school going adolescents differed from private school going adolescents on prosocial behaviour, stress and anxiety. Negative perception of relationship with family affected adolescents difficulties score, depression and stress. Similarly, negative perception of self-concept leads to higher difficulties score and lower prosocial behaviour score. The school going adolescents differed from non-school going

  11. Coherent mid-infrared supercontinuum generation with As2Se3 photonic crystal fiber and femtosecond Airy pulses

    NASA Astrophysics Data System (ADS)

    Yuan, Wu

    2015-12-01

    We discuss a novel method for generating hyper-broadband mid-infrared (MIR) supercontinua (SC) with coherent bandwidth from ~2 μm to ~10 μm by using As2Se3 photonic crystal fiber (PCF) and a 4.1 μm pump with femtosecond (fs) Airy pulse profile. Our simulations confirm that, when pumping in the normal dispersion region, the deceleration and self-healing properties of the Airy pulse can suppress the incoherent noise in modulational instability (MI) induced SC generation and maintain the pulse coherence over a long propagation distance. We also find that fs Airy pulse can generate an MIR SC with a broader coherent bandwidth than these can be achieved with fs parabolic secant pulse.

  12. Results from the Pronghorn field test using passive infrared spectroradiometers-CATSI and AIRIS

    NASA Astrophysics Data System (ADS)

    Jensen, James O.; Theriault, Jean-Marc; Bradette, Claude; Gittins, Christopher M.; Marinelli, William J.

    2002-02-01

    The Pronghorn Field Tests were held at the Nevada Test Site for a two-week period in June 2001. Two passive infrared sensors were tested for inclusion into the Joint Service Wide Area Detection Program. The Adaptive InfraRed Imaging Spectroradiometer (AIRIS) and Compact ATmospheric Sounding Interferometer (CATSI) systems were tested with good results. This field test was a joint effort between the U.S (SBCCOM) and Canada (DREV). Various chemicals were detected and quantified from a distance of 1.5 kilometers. Passive ranging of Chemical Plumes was demonstrated.

  13. Results of the Pronghorn field test using passive infrared spectroradiometers: CATSI and AIRIS

    NASA Astrophysics Data System (ADS)

    Jensen, James O.; Theriault, Jean-Marc; Bradette, Claude; Gittins, Christopher M.; Marinelli, William J.

    2002-08-01

    The Pronghorn Field Tests were held at the Nevada Test Site for a two-week period in June 2001. Two passive infrared sensors were tested for inclusion into the Joint Service Wide Area Detection Program. The Adaptive InfraRed Imaging Spectroradiometer (AIRIS) and Compact Atmospheric Sounding Interferometer (CATSI) systems were tested with good results. This field test was a joint effort between the US (SBCCOM) and Canada (DREV). Various chemicals were detected and quantified from a distance of 1.5 kilometers. Passive ranging of Chemical Plumes was demonstrated.

  14. Test drilling and aquifer test in the Marburg schist near Mount Airy, Frederick County, Maryland

    USGS Publications Warehouse

    Meyer, Gerald

    1955-01-01

    This memorandum summarizes briefly the data obtained by test drilling and in an aquifer test at Mount Airy, Md. The tests were a part of the State - Federal cooperative study of the ground-water resources of Frederick County, and it is intended that a more complete analysis of the test data will be included in a future report describing the ground-water resource of Frederick County. The purpose of this memorandum is to make the test data immediately available to the general public. Mount Airy is located along the Carroll-Frederick County boundary bout 2 miles north of the intersection of U.S. Highway 40 with the county boundary. Its population is approximately 1,000. The municipal well field, consisting of two drilled wells (fig. 1) is in a valley about one-half mile west of the center of Mount Airy, within about 400 feet of a small stream, and north of Prospect Road. Well 1, about 40 feet north of Prospect Road, is 125 feet deep, 8 inches in diameter, and reportedly yielded 265 gallons per minute (gpm) in 1947 and 201 gpm in a half hour test in March 1955. The writer determined during the tests described in this memorandum that the well has about 34 feet of casing. Well 2, 85 feet north of well 1, is 96 feet deep, 8 inches in diameter, and reportedly yielded 120 gpm in 1947 and 127 gpm in a half hour test in March 1955. The wells are equipped with deep-well turbine pumps powered by electric motors. Cenorally only well 1 is used, and it is pumped for only a few short intervals each day to meet the water requirements of the town (about 75,000 - 80,000 gallons daily). The reported yields of these wells are considerably higher than the average for crystalline-rock wells in the Piedmont of Maryland. The test drilling was done under contract with Edward I. Brown, well driller, between May 3 and May 12, 1955. Water-supply facilities of the town of Mount Airy were kindly made available for the aquifer tests from May 22 to May 30, 1955. The pumping tests consisted of a

  15. Deficient cardiovascular stress reactivity predicts poor executive functions in adults with attention-deficit/hyperactivity disorder.

    PubMed

    Hirvikoski, Tatja; Olsson, Erik M G; Nordenstrom, Anna; Lindholm, Torun; Nordstrom, Anna-Lena; Lajic, Svetlana

    2011-01-01

    Associations between cardiovascular stress markers, subjective stress reactivity, and executive functions were studied in 60 adults (30 with attention-deficit/hyperactivity disorder, ADHD, and 30 controls) using the Paced Auditory Serial Addition Test (PASAT, a test of executive functions) as a cognitive stressor. Despite higher self-perceived stress, the adults with ADHD showed lower or atypical cardiovascular stress reactivity, which was associated with poorer performance on PASAT. Using cardiovascular stress markers, subjective stress, and results on PASAT as predictors in a logistic regression, 83.3% of the ADHD group and 86.9% of the controls could be classified correctly.

  16. Asymptotics for the Covariance of the Airy2 Process

    NASA Astrophysics Data System (ADS)

    Shinault, Gregory; Tracy, Craig A.

    2011-04-01

    In this paper we compute some of the higher order terms in the asymptotic behavior of the two point function {P}({A}2(0)≤ s1,A2(t)≤ s2), extending the previous work of Adler and van Moerbeke (arXiv:math.PR/0302329; Ann. Probab. 33, 1326-1361, 2005) and Widom (J. Stat. Phys. 115, 1129-1134, 2004). We prove that it is possible to represent any order asymptotic approximation as a polynomial and integrals of the Painlevé II function q and its derivative q'. Further, for up to tenth order we give this asymptotic approximation as a linear combination of the Tracy-Widom GUE density function f 2 and its derivatives. As a corollary to this, the asymptotic covariance is expressed up to tenth order in terms of the moments of the Tracy-Widom GUE distribution.

  17. Diabetes and mitochondrial function: Role of hyperglycemia and oxidative stress

    SciTech Connect

    Rolo, Anabela P.; Palmeira, Carlos M. . E-mail: palmeira@ci.uc.pt

    2006-04-15

    Hyperglycemia resulting from uncontrolled glucose regulation is widely recognized as the causal link between diabetes and diabetic complications. Four major molecular mechanisms have been implicated in hyperglycemia-induced tissue damage: activation of protein kinase C (PKC) isoforms via de novo synthesis of the lipid second messenger diacylglycerol (DAG), increased hexosamine pathway flux, increased advanced glycation end product (AGE) formation, and increased polyol pathway flux. Hyperglycemia-induced overproduction of superoxide is the causal link between high glucose and the pathways responsible for hyperglycemic damage. In fact, diabetes is typically accompanied by increased production of free radicals and/or impaired antioxidant defense capabilities, indicating a central contribution for reactive oxygen species (ROS) in the onset, progression, and pathological consequences of diabetes. Besides oxidative stress, a growing body of evidence has demonstrated a link between various disturbances in mitochondrial functioning and type 2 diabetes. Mutations in mitochondrial DNA (mtDNA) and decreases in mtDNA copy number have been linked to the pathogenesis of type 2 diabetes. The study of the relationship of mtDNA to type 2 diabetes has revealed the influence of the mitochondria on nuclear-encoded glucose transporters, glucose-stimulated insulin secretion, and nuclear-encoded uncoupling proteins (UCPs) in {beta}-cell glucose toxicity. This review focuses on a range of mitochondrial factors important in the pathogenesis of diabetes. We review the published literature regarding the direct effects of hyperglycemia on mitochondrial function and suggest the possibility of regulation of mitochondrial function at a transcriptional level in response to hyperglycemia. The main goal of this review is to include a fresh consideration of pathways involved in hyperglycemia-induced diabetic complications.

  18. Improvement in cerebral function with treatment of posttraumatic stress disorder.

    PubMed

    Roy, Michael J; Francis, Jennifer; Friedlander, Joshua; Banks-Williams, Lisa; Lande, Raymond G; Taylor, Patricia; Blair, James; McLellan, Jennifer; Law, Wendy; Tarpley, Vanita; Patt, Ivy; Yu, Henry; Mallinger, Alan; Difede, Joann; Rizzo, Albert; Rothbaum, Barbara

    2010-10-01

    Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are signature illnesses of the Iraq and Afghanistan wars, but current diagnostic and therapeutic measures for these conditions are suboptimal. In our study, functional magnetic resonance imaging (fMRI) is used to try to differentiate military service members with: PTSD and mTBI, PTSD alone, mTBI alone, and neither PTSD nor mTBI. Those with PTSD are then randomized to virtual reality exposure therapy or imaginal exposure. fMRI is repeated after treatment and along with the Clinician-Administered PTSD Scale (CAPS) and Clinical Global Impression (CGI) scores to compare with baseline. Twenty subjects have completed baseline fMRI scans, including four controls and one mTBI only; of 15 treated for PTSD, eight completed posttreatment scans. Most subjects have been male (93%) and Caucasian (83%), with a mean age of 34. Significant improvements are evident on fMRI scans, and corroborated by CGI scores, but CAPS scores improvements are modest. In conclusion, CGI scores and fMRI scans indicate significant improvement in PTSD in both treatment arms, though CAPS score improvements are less robust. PMID:20955336

  19. Functional network topology associated with posttraumatic stress disorder in veterans.

    PubMed

    Kennis, M; van Rooij, S J H; van den Heuvel, M P; Kahn, R S; Geuze, E

    2016-01-01

    Posttraumatic stress disorder (PTSD) is a disabling disorder associated with resting state functional connectivity alterations. However, whether specific brain regions are altered in PTSD or whether the whole brain network organization differs remains unclear. PTSD can be treated with trauma-focused therapy, although only half of the patients recover after treatment. In order to better understand PTSD psychopathology our aim was to study resting state networks in PTSD before and after treatment. Resting state functional magnetic resonance images were obtained from veterans with PTSD (n = 50) and controls (combat and civilian controls; n = 54) to explore which network topology properties (degree and clustering coefficient) of which brain regions are associated with PTSD. Then, PTSD-associated brain regions were investigated before and after treatment. PTSD patients were subdivided in persistent (n = 22) and remitted PTSD patients (n = 17), and compared with combat controls (n = 22), who were also reassessed. Prior to treatment associations with PTSD were found for the degree of orbitofrontal, and temporoparietal brain regions, and for the clustering coefficient of the anterior cingulate cortex. No significant effects were found over the course of treatment. Our results are in line with previous resting state studies, showing resting state connectivity alterations in the salience network and default mode network in PTSD, and also highlight the importance of other brain regions. However, network metrics do not seem to change over the course of treatment. This study contributes to a better understanding of the psychopathology of PTSD. PMID:26900570

  20. [Function of pancreas transplants in increased metabolic stress].

    PubMed

    Teuscher, A U; Seaquist, E R; Barrou, Z; Kendall, D M; Robertson, R P

    1995-01-01

    Patients undergoing successful pancreas transplantation have normal glucose levels in the fasting and fed states and normal levels of hemoglobin A1c without use of exogenous inulin or any other medications for diabetes. In some of these patients, these measures have remained stable for more than 10 years. Additionally pancreas transplant recipients recover from short-term hypoglycemia produced by an intravenous pulse of insulin. However, metabolic success has been determined by relatively routine, unsophisticated tests such as oral and intravenous glucose tolerance tests or stimulation with intravenous arginine. These tests may not provide measures of the functional reserve of the pancreas, which is called on during periods of maximal stress. Consequently, we designed studies to ascertain beta and alpha cell performance in recipients of whole pancreas transplants and recipients of a segment of a living related donor. All recipients were recruited from the University of Minnesota Transplant Registry, Minneapolis, Minnesota. Successfully transplanted recipients were subjected to prolonged hyperglycemia to assess insulin secretory reserve using the method of glucose potentiation of arginine induced insulin secretion and to prolonged hypoglycemia to assess glucagon responsiveness and hepatic glucose production using the technique of the hyperinsulinemic hypoglycemic clamp. Our studies show that pancreas transplant recipients have markedly diminished insulin secretory reserve, a defect not evident with conventional tests of beta-cell function. No difference was found between the whole graft and segmental graft recipients. Pancreas transplantation restores the defective glucagon secretory response and enhances hepatic glucose production during prolonged hypoglycemia in subjects with type I diabetes. We conclude that pancreas transplantation does not completely restore beta-cell secretory reserve. This defect might be probably caused in part by cyclosporine and by the

  1. Perspectives on stress resilience and adolescent neurobehavioral function.

    PubMed

    Romeo, Russell D

    2015-01-01

    Interest in adolescence as a crucial stage of neurobehavioral maturation is growing, as is the concern of how stress may perturb this critical period of development. Though it is well recognized that stress-related vulnerabilities increase during adolescence, not all adolescent individuals are uniformly affected by stress nor do stressful experiences inevitability lead to negative outcomes. Indeed, many adolescents show resilience to stress-induced dysfunctions. However, relatively little is known regarding the mechanisms that may mediate resilience to stress in adolescence. The goal of this brief review is to bring together a few separate, yet related lines of research that highlight specific variables that may influence stress resilience during adolescence, including early life programming of the hypothalamic-pituitary-adrenal (HPA) axis, stress inoculation, and genetic predisposition. Though we are far from a clear understanding of the factors that mediate resistance to stress-induced dysfunctions, it is imperative that we identify and delineate these aspects of resilience to help adolescents reach their full potential, even in the face of adversity. PMID:27589663

  2. Endoplasmic Reticulum Stress Links Oxidative Stress to Impaired Pancreatic Beta-Cell Function Caused by Human Oxidized LDL.

    PubMed

    Plaisance, Valérie; Brajkovic, Saška; Tenenbaum, Mathie; Favre, Dimitri; Ezanno, Hélène; Bonnefond, Amélie; Bonner, Caroline; Gmyr, Valéry; Kerr-Conte, Julie; Gauthier, Benoit R; Widmann, Christian; Waeber, Gérard; Pattou, François; Froguel, Philippe; Abderrahmani, Amar

    2016-01-01

    Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells. Silencing of Chop and inhibition of ER stress markers by the chemical chaperone phenyl butyric acid (PBA) prevented cell death caused by oxidized LDL. Finally, we found that oxidative stress accounts for activation of ER stress markers induced by oxidized LDL. Induction of Chop/CHOP and p58IPK/P58IPK by oxidized LDL was mimicked by hydrogen peroxide and was blocked by co-treatment with the N-acetylcystein antioxidant. As a conclusion, the harmful effects of oxidized LDL in beta-cells requires ER stress activation in a manner that involves oxidative stress. This mechanism may account for impaired beta-cell function in diabetes and can be reversed by antioxidant treatment. PMID:27636901

  3. Endoplasmic Reticulum Stress Links Oxidative Stress to Impaired Pancreatic Beta-Cell Function Caused by Human Oxidized LDL

    PubMed Central

    Favre, Dimitri; Ezanno, Hélène; Bonnefond, Amélie; Bonner, Caroline; Gmyr, Valéry; Kerr-Conte, Julie; Gauthier, Benoit R.; Widmann, Christian; Waeber, Gérard; Pattou, François; Froguel, Philippe; Abderrahmani, Amar

    2016-01-01

    Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells. Silencing of Chop and inhibition of ER stress markers by the chemical chaperone phenyl butyric acid (PBA) prevented cell death caused by oxidized LDL. Finally, we found that oxidative stress accounts for activation of ER stress markers induced by oxidized LDL. Induction of Chop/CHOP and p58IPK/P58IPK by oxidized LDL was mimicked by hydrogen peroxide and was blocked by co-treatment with the N-acetylcystein antioxidant. As a conclusion, the harmful effects of oxidized LDL in beta-cells requires ER stress activation in a manner that involves oxidative stress. This mechanism may account for impaired beta-cell function in diabetes and can be reversed by antioxidant treatment. PMID:27636901

  4. Neuroendocrine circuits governing energy balance and stress regulation: functional overlap and therapeutic implications

    PubMed Central

    Ulrich-Lai, Yvonne M.; Ryan, Karen K.

    2014-01-01

    Significant co-morbidities between obesity-related metabolic disease and stress-related psychological disorders suggest important functional interactions between energy balance and brain stress integration. Largely overlapping neural circuits control these systems, and this anatomical arrangement optimizes opportunities for mutual influence. Here we first review the current literature identifying effects of metabolic neuroendocrine signals on stress regulation, and vice versa. Next, the contributions of reward driven food intake to these metabolic and stress interactions are discussed. Lastly, we consider the inter-relationships among metabolism, stress and reward in light of their important implications in the development of therapies for metabolism- or stress-related disease. PMID:24630812

  5. A Study on Propagation Characteristic of One-dimensional Stress Wave in Functionally Graded Armor Composites

    NASA Astrophysics Data System (ADS)

    Yang, S. Y.; Liu, X.; Cao, D. F.; Mei, H.; Lei, Z. T.; Liu, L. S.

    2013-03-01

    The development of Functionally Graded Materials (FGM) for energy-absorbing applications requires understanding of stress wave propagation in these structures in order to optimize their resistance to failure. One-dimensional stress wave in FGM composites under elastic and plastic wave loading have been investigated. The stress distributions through the thickness and stress status have been analyzed and some comparisons have been done with the materials of sharp interfaces (two-layered material). The results demonstrate that the gradient structure design greatly decreases the severity of the stress concentrations at the interfaces and there are no clear differences in stress distribution in FGM composites under elastic and plastic wave loading.

  6. Impaired Functional Connectivity in the Prefrontal Cortex: A Mechanism for Chronic Stress-Induced Neuropsychiatric Disorders.

    PubMed

    Negrón-Oyarzo, Ignacio; Aboitiz, Francisco; Fuentealba, Pablo

    2016-01-01

    Chronic stress-related psychiatric diseases, such as major depression, posttraumatic stress disorder, and schizophrenia, are characterized by a maladaptive organization of behavioral responses that strongly affect the well-being of patients. Current evidence suggests that a functional impairment of the prefrontal cortex (PFC) is implicated in the pathophysiology of these diseases. Therefore, chronic stress may impair PFC functions required for the adaptive orchestration of behavioral responses. In the present review, we integrate evidence obtained from cognitive neuroscience with neurophysiological research with animal models, to put forward a hypothesis that addresses stress-induced behavioral dysfunctions observed in stress-related neuropsychiatric disorders. We propose that chronic stress impairs mechanisms involved in neuronal functional connectivity in the PFC that are required for the formation of adaptive representations for the execution of adaptive behavioral responses. These considerations could be particularly relevant for understanding the pathophysiology of chronic stress-related neuropsychiatric disorders. PMID:26904302

  7. Impaired Functional Connectivity in the Prefrontal Cortex: A Mechanism for Chronic Stress-Induced Neuropsychiatric Disorders

    PubMed Central

    Negrón-Oyarzo, Ignacio; Aboitiz, Francisco; Fuentealba, Pablo

    2016-01-01

    Chronic stress-related psychiatric diseases, such as major depression, posttraumatic stress disorder, and schizophrenia, are characterized by a maladaptive organization of behavioral responses that strongly affect the well-being of patients. Current evidence suggests that a functional impairment of the prefrontal cortex (PFC) is implicated in the pathophysiology of these diseases. Therefore, chronic stress may impair PFC functions required for the adaptive orchestration of behavioral responses. In the present review, we integrate evidence obtained from cognitive neuroscience with neurophysiological research with animal models, to put forward a hypothesis that addresses stress-induced behavioral dysfunctions observed in stress-related neuropsychiatric disorders. We propose that chronic stress impairs mechanisms involved in neuronal functional connectivity in the PFC that are required for the formation of adaptive representations for the execution of adaptive behavioral responses. These considerations could be particularly relevant for understanding the pathophysiology of chronic stress-related neuropsychiatric disorders. PMID:26904302

  8. Iron accumulation with age, oxidative stress and functional decline.

    PubMed

    Xu, Jinze; Knutson, Mitchell D; Carter, Christy S; Leeuwenburgh, Christiaan

    2008-01-01

    Identification of biological mediators in sarcopenia is pertinent to the development of targeted interventions to alleviate this condition. Iron is recognized as a potent pro-oxidant and a catalyst for the formation of reactive oxygen species in biological systems. It is well accepted that iron accumulates with senescence in several organs, but little is known about iron accumulation in muscle and how it may affect muscle function. In addition, it is unclear if interventions which reduced age-related loss of muscle quality, such as calorie restriction, impact iron accumulation. We investigated non-heme iron concentration, oxidative stress to nucleic acids in gastrocnemius muscle and key indices of sarcopenia (muscle mass and grip strength) in male Fischer 344 X Brown Norway rats fed ad libitum (AL) or a calorie restricted diet (60% of ad libitum food intake starting at 4 months of age) at 8, 18, 29 and 37 months of age. Total non-heme iron levels in the gastrocnemius muscle of AL rats increased progressively with age. Between 29 and 37 months of age, the non-heme iron concentration increased by approximately 200% in AL-fed rats. Most importantly, the levels of oxidized RNA in gastrocnemius muscle of AL rats were significantly increased as well. The striking age-associated increase in non-heme iron and oxidized RNA levels and decrease in sarcopenia indices were all attenuated in the calorie restriction (CR) rats. These findings strongly suggest that the age-related iron accumulation in muscle contributes to increased oxidative damage and sarcopenia, and that CR effectively attenuates these negative effects.

  9. Iron Accumulation with Age, Oxidative Stress and Functional Decline

    PubMed Central

    Xu, Jinze; Knutson, Mitchell D.; Carter, Christy S.; Leeuwenburgh, Christiaan

    2008-01-01

    Identification of biological mediators in sarcopenia is pertinent to the development of targeted interventions to alleviate this condition. Iron is recognized as a potent pro-oxidant and a catalyst for the formation of reactive oxygen species in biological systems. It is well accepted that iron accumulates with senescence in several organs, but little is known about iron accumulation in muscle and how it may affect muscle function. In addition, it is unclear if interventions which reduced age-related loss of muscle quality, such as calorie restriction, impact iron accumulation. We investigated non-heme iron concentration, oxidative stress to nucleic acids in gastrocnemius muscle and key indices of sarcopenia (muscle mass and grip strength) in male Fischer 344 X Brown Norway rats fed ad libitum (AL) or a calorie restricted diet (60% of ad libitum food intake starting at 4 months of age) at 8, 18, 29 and 37 months of age. Total non-heme iron levels in the gastrocnemius muscle of AL rats increased progressively with age. Between 29 and 37 months of age, the non-heme iron concentration increased by approximately 200% in AL-fed rats. Most importantly, the levels of oxidized RNA in gastrocnemius muscle of AL rats were significantly increased as well. The striking age-associated increase in non-heme iron and oxidized RNA levels and decrease in sarcopenia indices were all attenuated in the calorie restriction (CR) rats. These findings strongly suggest that the age-related iron accumulation in muscle contributes to increased oxidative damage and sarcopenia, and that CR effectively attenuates these negative effects. PMID:18682742

  10. Stress tolerances of nullmutants of function-unknown genes encoding menadione stress-responsive proteins in Aspergillus nidulans.

    PubMed

    Leiter, Éva; Bálint, Mihály; Miskei, Márton; Orosz, Erzsébet; Szabó, Zsuzsa; Pócsi, István

    2016-07-01

    A group of menadione stress-responsive function-unkown genes of Aspergillus nidulans (Locus IDs ANID_03987.1, ANID_06058.1, ANID_10219.1, and ANID_10260.1) was deleted and phenotypically characterized. Importantly, comparative and phylogenetic analyses of the tested A. nidulans genes and their orthologs shed light only on the presence of a TANGO2 domain with NRDE protein motif in the translated ANID_06058.1 gene but did not reveal any recognizable protein-encoding domains in other protein sequences. The gene deletion strains were subjected to oxidative, osmotic, and metal ion stress and, surprisingly, only the ΔANID_10219.1 mutant showed an increased sensitivity to 0.12 mmol l(-1) menadione sodium bisulfite. The gene deletions affected the stress sensitivities (tolerances) irregularly, for example, some strains grew more slowly when exposed to various oxidants and/or osmotic stress generating agents, meanwhile the ΔANID_10260.1 mutant possessed a wild-type tolerance to all stressors tested. Our results are in line with earlier studies demonstrating that the deletions of stress-responsive genes do not confer necessarily any stress-sensitivity phenotypes, which can be attributed to compensatory mechanisms based on other elements of the stress response system with overlapping functions.

  11. Evolving stresses in latex films as a function of temperature.

    PubMed

    Yow, Huai Nyin; Beristain, Itxaso; Goikoetxea, Monika; Barandiaran, Maria J; Routh, Alexander F

    2010-05-01

    Latex films were dried on a flexible substrate, and the substrate deflection was monitored over time to give an averaged film stress-evolution profile. Films were dried at various temperatures below and above the minimum film-formation temperature of the latex dispersion. The effect of polymer rheology, which is a temperature-dependent parameter, on film formation, was investigated. The reliability of the Stoney model in predicting film stress from substrate curvature was also examined and compared to the Euler-Bernoulli model. It was shown that the linearized Stoney model was unsuitable for the larger measured stresses. PMID:20387802

  12. The Role of Family Functioning in the Stress Process of Dementia Caregivers: A Structural Family Framework

    ERIC Educational Resources Information Center

    Mitrani, Victoria B.; Lewis, John E.; Feaster, Daniel J.; Czaja, Sara J.; Eisdorfer, Carl; Schulz, Richard; Szapocznik, Jose

    2006-01-01

    Purpose: The purpose of the study was to evaluate the role of family functioning in the stress process in a sample of caregivers of dementia patients by using a structural family framework. The stress-process model of caregiver distress included family functioning as an intervening variable in the relationship between objective burden and…

  13. Lactobacillus casei combats acid stress by maintaining cell membrane functionality.

    PubMed

    Wu, Chongde; Zhang, Juan; Wang, Miao; Du, Guocheng; Chen, Jian

    2012-07-01

    Lactobacillus casei strains have traditionally been recognized as probiotics and frequently used as adjunct culture in fermented dairy products where lactic acid stress is a frequently encountered environmental condition. We have investigated the effect of lactic acid stress on the cell membrane of L. casei Zhang [wild type (WT)] and its acid-resistant mutant Lbz-2. Both strains were grown under glucose-limiting conditions in chemostats; following challenge by low pH, the cell membrane stress responses were investigated. In response to acid stress, cell membrane fluidity decreased and its fatty acid composition changed to reduce the damage caused by lactic acid. Compared with the WT, the acid-resistant mutant exhibited numerous survival advantages, such as higher membrane fluidity, higher proportions of unsaturated fatty acids, and higher mean chain length. In addition, cell integrity analysis showed that the mutant maintained a more intact cellular structure and lower membrane permeability after environmental acidification. These results indicate that alteration in membrane fluidity, fatty acid distribution, and cell integrity are common mechanisms utilized by L. casei to withstand severe acidification and to reduce the deleterious effect of lactic acid on the cell membrane. This detailed comparison of cell membrane responses between the WT and mutant add to our knowledge of the acid stress adaptation and thus enable new strategies to be developed aimed at improving the industrial performance of this species under acid stress. PMID:22366811

  14. Stress, Social Support and Functioning: Beyond the Stress-Buffering Effect.

    ERIC Educational Resources Information Center

    Mitchell, Roger E.

    As the belief that social support and coping can moderate the impact of stress becomes part of the common wisdom in the mental health field, the demand for support-oriented interventions has increased. However, a review of the stress-buffering research indicates that the effect of support is more modest and more complex than most researchers…

  15. The Role of Stress Exposure and Family Functioning in Internalizing Outcomes of Urban Families

    PubMed Central

    Henry, David B.; Tolan, Patrick H.; Strachan, Martha K.

    2013-01-01

    Although research suggests that stress exposure and family functioning are associated with internalizing problems in adolescents and caregivers, surprisingly few studies have investigated the mechanisms that underlie this association. To determine whether family functioning buffers the development of internalizing problems in stress-exposed families, we assessed the relation between stress exposure, family functioning, and internalizing symptoms among a large sample of inner-city male youth and their caregivers living in poverty across five waves of data collection. We hypothesized that stress exposure and family functioning would predict development of subsequent youth and caregiver internalizing problems and that family functioning would moderate this relation, with higher functioning families demonstrating greater resiliency to stress exposure. We used a longitudinal, prospective design to evaluate whether family functioning (assessed at waves one through four) activated or buffered the effects of stress exposure (assessed at wave one) on subsequent internalizing symptoms (assessed at waves four and five). Stress from Developmental Transitions and family functioning were significant predictors of depressive symptoms and anxiety in youth; however, family functioning did not moderate the relation. Family functioning mediated the relation between stress from Daily Hassles and internalizing outcomes suggesting that poor parenting practices, low structure, and low emotional cohesion activate depression and anxiety in youth exposed to chronic and frequent everyday stressors. Surprisingly, only family functioning predicted depressive symptoms in caregivers. Results validate the use of a comprehensive, multi-informant assessment of stress when investigating internalizing outcomes in youth and support using family-based interventions in the treatment and prevention of internalizing. PMID:25601821

  16. Propagation of an Airy-Gaussian vortex beam in linear and nonlinear media

    NASA Astrophysics Data System (ADS)

    Chen, Chidao; Peng, Xi; Chen, Bo; Peng, Yulian; Zhou, Meiling; Yang, Xiangbo; Deng, Dongmei

    2016-05-01

    We investigate the propagation of an Airy-Gaussian vortex (AiGV) beam in free space and Kerr media. It is interesting to see that the beam will perform self-healing and main lobe focusing both in free space and Kerr media when the vortex locates at the center of the plane. By controlling the number of the topological charge, the beam distribution factor χ 0 and the position of the vortex, we can control the intensity distribution of the AiGV beam in the out plane both in free space and Kerr media. It is found that when the vortex is close to the center of the plane, it has a strong effect on the intensity distribution of the beam. When the beam propagates in the number of the topological charge, the partial collapse will take place even with low initial input power. We find that the main lobe focusing contributes to this partial collapse.

  17. Predicting the past: ancient eclipses and Airy, Newcomb, and Huxley on the authority of science.

    PubMed

    Stanley, Matthew

    2012-06-01

    Greek historical accounts of ancient eclipses were an important, if peculiar, focus of scientific attention in the nineteenth century. Victorian-era astronomers tried to correct the classical histories using scientific methods, then used those histories as data with which to calibrate their lunar theories, then rejected the histories as having any relevance at all. The specific dating of these eclipses--apparently a simple exercise in celestial mechanics--became bound up with tensions between scientific and humanistic approaches to the past as well as with wider social debates over the power and authority of science in general. The major figures discussed here, including G. B. Airy, Simon Newcomb, and T. H. Huxley, argued that the critical question was whether science could speak authoritatively about the past. To them, the ability of science to talk about the past indicated its power to talk about the future; it was also the fulcrum of fierce boundary disputes among science, history, and religion.

  18. Predicting the past: ancient eclipses and Airy, Newcomb, and Huxley on the authority of science.

    PubMed

    Stanley, Matthew

    2012-06-01

    Greek historical accounts of ancient eclipses were an important, if peculiar, focus of scientific attention in the nineteenth century. Victorian-era astronomers tried to correct the classical histories using scientific methods, then used those histories as data with which to calibrate their lunar theories, then rejected the histories as having any relevance at all. The specific dating of these eclipses--apparently a simple exercise in celestial mechanics--became bound up with tensions between scientific and humanistic approaches to the past as well as with wider social debates over the power and authority of science in general. The major figures discussed here, including G. B. Airy, Simon Newcomb, and T. H. Huxley, argued that the critical question was whether science could speak authoritatively about the past. To them, the ability of science to talk about the past indicated its power to talk about the future; it was also the fulcrum of fierce boundary disputes among science, history, and religion. PMID:22908421

  19. Sharply autofocused ring-Airy beams transforming into non-linear intense light bullets

    NASA Astrophysics Data System (ADS)

    Panagiotopoulos, P.; Papazoglou, D. G.; Couairon, A.; Tzortzakis, S.

    2013-10-01

    Controlling the propagation of intense optical wavepackets in transparent media is not a trivial task. During propagation, low- and high-order non-linear effects, including the Kerr effect, multiphoton absorption and ionization, lead to an uncontrolled complex reshaping of the optical wavepacket that involves pulse splitting, refocusing cycles in space and significant variations of the focus. Here we demonstrate both numerically and experimentally that intense, abruptly autofocusing beams in the form of accelerating ring-Airy beams are able to reshape into non-linear intense light-bullet wavepackets propagating over extended distances, while their positioning in space is extremely well defined. These unique wavepackets can offer significant advantages in numerous fields such as the generation of high harmonics and attosecond physics or the precise micro-engineering of materials.

  20. Development of Maladaptive Coping: A Functional Adaptation to Chronic, Uncontrollable Stress

    PubMed Central

    Wadsworth, Martha E.

    2015-01-01

    Health disparities are rooted in childhood and stem from adverse early environments that damage physiologic stress-response systems. Developmental psychobiological models of the effects of chronic stress account for both the negative effects of a stress-response system calibrated to a dangerous and unpredictable environment from a health perspective, and the positive effects of such an adaptively calibrated stress response from a functional perspective. Our research suggests that contexts that produce functionally adapted physiologic responses to stress also encourage a functionally adapted coping response—coping that can result in maladjustment in physical and mental health, but enables children to grow and develop within those contexts. In this article, I highlight the value of reframing maladaptive coping as functional adaptation to understand more completely the development of children’s coping in different contexts, and the value of such a conceptual shift for coping-based theory, research, and intervention. PMID:26019717

  1. Coronary flow and left ventricular function during environmental stress.

    NASA Technical Reports Server (NTRS)

    Erickson, H. H.; Adams, J. D.; Stone, H. L.; Sandler, H.

    1972-01-01

    A canine model was used to study the effects of different environmental stresses on the heart and coronary circulation. The heart was surgically instrumented to measure coronary blood flow, left ventricular pressure, and other cardiovascular variables. Coronary flow was recorded by telemetry. Physiologic data were processed and analyzed by analog and digital computers. By these methods the physiologic response to altitude hypoxia, carbon monoxide, hypercapnia, acceleration, exercise, and the interaction of altitude hypoxia and carbon monoxide were described. The effects of some of these stresses on the heart and coronary circulation are discussed.

  2. Adult hippocampal neurogenesis is functionally important for stress-induced social avoidance

    PubMed Central

    Lagace, Diane C.; Donovan, Michael H.; DeCarolis, Nathan A.; Farnbauch, Laure A.; Malhotra, Shveta; Berton, Olivier; Nestler, Eric J.; Krishnan, Vaishnav; Eisch, Amelia J.

    2010-01-01

    The long-term response to chronic stress is variable, with some individuals developing maladaptive functioning, although other “resilient” individuals do not. Stress reduces neurogenesis in the dentate gyrus subgranular zone (SGZ), but it is unknown if stress-induced changes in neurogenesis contribute to individual vulnerability. Using a chronic social defeat stress model, we explored whether the susceptibility to stress-induced social avoidance was related to changes in SGZ proliferation and neurogenesis. Immediately after social defeat, stress-exposed mice (irrespective of whether they displayed social avoidance) had fewer proliferating SGZ cells labeled with the S-phase marker BrdU. The decrease was transient, because BrdU cell numbers were normalized 24 h later. The survival of BrdU cells labeled before defeat stress was also not altered. However, 4 weeks later, mice that displayed social avoidance had more surviving dentate gyrus neurons. Thus, dentate gyrus neurogenesis is increased after social defeat stress selectively in mice that display persistent social avoidance. Supporting a functional role for adult-generated dentate gyrus neurons, ablation of neurogenesis via cranial ray irradiation robustly inhibited social avoidance. These data show that the time window after cessation of stress is a critical period for the establishment of persistent cellular and behavioral responses to stress and that a compensatory enhancement in neurogenesis is related to the long-term individual differences in maladaptive responses to stress. PMID:20176946

  3. Stress-induced changes in skin barrier function in healthy women.

    PubMed

    Altemus, M; Rao, B; Dhabhar, F S; Ding, W; Granstein, R D

    2001-08-01

    Despite clear exacerbation of several skin disorders by stress, the effect of psychologic or exertional stress on human skin has not been well studied. We investigated the effect of three different stressors, psychologic interview stress, sleep deprivation, and exercise, on several dermatologic measures: transepidermal water loss, recovery of skin barrier function after tape stripping, and stratum corneum water content (skin conductance). We simultaneously measured the effects of stress on plasma levels of several stress-response hormones and cytokines, natural killer cell activity, and absolute numbers of peripheral blood leukocytes. Twenty-five women participated in a laboratory psychologic interview stress, 11 women participated in one night of sleep deprivation, and 10 women participated in a 3 d exercise protocol. The interview stress caused a delay in the recovery of skin barrier function, as well as increases in plasma cortisol, norepinephrine, interleukin-1beta and interleukin-10, tumor necrosis factor-alpha, and an increase in circulating natural killer cell activity and natural killer cell number. Sleep deprivation also decreased skin barrier function recovery and increased plasma interleukin-1beta, tumor necrosis factor-alpha, and natural killer cell activity. The exercise stress did not affect skin barrier function recovery, but caused an increase in natural killer cell activity and circulating numbers of both cytolytic T lymphocytes and helper T cells. In addition, cytokine responses to the interview stress were inversely correlated with changes in barrier function recovery. These results suggest that acute psychosocial and sleep deprivation stress disrupts skin barrier function homeostasis in women, and that this disruption may be related to stress-induced changes in cytokine secretion. PMID:11511309

  4. Production of Functional Proteins: Balance of Shear Stress and Gravity

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas John (Inventor); Hammond, Timothy Grant (Inventor); Haysen, James Howard (Inventor)

    2005-01-01

    The present invention provides for a method of culturing cells and inducing the expression of at least one gene in the cell culture. The method provides for contacting the cell with a transcription factor decoy oligonucleotide sequence directed against a nucleotide sequence encoding a shear stress response element.

  5. Functional genomics of abiotic stress responses in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable crop production in the U.S., as well as in other areas of the world, will rely upon the crop’s ability to yield under progressively limiting conditions: marginal soils, decreased water availability, and oftentimes critical temperature stress. Enhanced understanding of the physiological...

  6. Central circulatory hemodynamics as a function of gravitational stress

    NASA Technical Reports Server (NTRS)

    Latham, Rick D.; White, C. D.; Fanton, J. W.; Owens, R. W.; Barber, J. F.; Lewkowski, B. E.; Goff, O. T.

    1991-01-01

    This study focuses on an evaluation of the central hemodynamics in a nonhuman primate model to variations in gravitational states. The baboon, phylogenectically close to man, was chosen as the human surrogate. The study environments selected are head-down and head-up tilt in the physiology laboratory, centrifugation to test hypergravic stress, and parabolic flights to test transient acute responses to microgravity.

  7. Endoplasmic reticulum stress and the on site function of resident PTP1B.

    PubMed

    Popov, Doina

    2012-06-15

    Growing evidence links the stress at the endoplasmic reticulum (ER) to pathologies such as diabetes mellitus, obesity, liver, heart, renal and neurodegenerative diseases, endothelial dysfunction, atherosclerosis, and cancer. Therefore, identification of molecular pathways beyond ER stress and their appropriate modulation might alleviate the stress, and direct toward novel tools to fight this disturbance. An interesting resident of the ER membrane is protein tyrosine phosphatase 1B (PTP1B), an enzyme that negatively regulates insulin and leptin signaling, contributing to insulin and leptin resistance. Recently, new functions of PTP1B have been established linked to ER stress response. This review evaluates the novel data on ER stressors, discusses the mechanisms beyond PTP1B function in the ER stress response, and emphasizes the potential therapeutic exploitation of PTP1B to relieve ER stress. PMID:22609202

  8. Protective function of nitric oxide on marine phytoplankton under abiotic stresses.

    PubMed

    Li, Peifeng; Liu, Chun-Ying; Liu, Huanhuan; Zhang, Qiang; Wang, Lili

    2013-09-01

    As an important signaling molecule, nitric oxide (NO) plays diverse physiological functions in plants, which has gained particular attention in recent years. We investigated the roles of NO in the growth of marine phytoplankton Platymonas subcordiforms and Skeletonema costatum under abiotic stresses. The growth of these two microalgae was obviously inhibited under non-metal stress (sodium selenium, Na2SeO3), heavy metal stress (lead nitrate, Pb(NO3)2), pesticide stress (methomyl) and UV radiation stress. After the addition of different low concentrations of exogenous NO (10(-10)-10(-8) mol L(-1)) twice each day during cultivation, the growth of these two microalgae was obviously promoted. Results showed that NO could relieve the oxidative stresses to protect the growth of the two microalgae. For different environmental stress, there is a different optimum NO concentration for marine phytoplankton. It is speculated that the protective effect of NO is related to its antioxidant ability. PMID:23810732

  9. Adaptogenic potential of curcumin in experimental chronic stress and chronic unpredictable stress-induced memory deficits and alterations in functional homeostasis.

    PubMed

    Bhatia, Nitish; Jaggi, Amteshwar Singh; Singh, Nirmal; Anand, Preet; Dhawan, Ravi

    2011-07-01

    The present study was designed to investigate the role of curcumin in chronic stress and chronic unpredictable stress-induced memory deficits and alteration of functional homeostasis in mice. Chronic stress was induced by immobilizing the animal for 2 h daily for 10 days, whereas chronic unpredictable stress was induced by employing a battery of stressors of variable magnitude and time for 10 days. Curcumin was administered to drug-treated mice prior to induction of stress. Body weight, adrenal gland weight, ulcer index and biochemical levels of glucose, creatine kinase, cholesterol, corticosterone, thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) were evaluated to assess stress-induced functional changes. Memory deficits were evaluated using the elevated plus maze (EPM) model. Chronic stress and chronic unpredictable stress significantly increased the levels of corticosterone, glucose and creatine kinase and decreased cholesterol levels. Moreover, chronic stress and chronic unpredictable stress resulted in severe memory deficits along with adrenal hypertrophy, weight loss and gastric ulceration. Chronic stress and chronic unpredictable stress also increased oxidative stress assessed in terms of increase in TBARS and decrease in GSH levels. Pretreatment with curcumin (25 and 50 mg/kg p.o.) attenuated chronic stress and chronic unpredictable stress-associated memory deficits, biochemical alterations, pathological outcomes and oxidative stress. It may be concluded that curcumin-mediated antioxidant actions and decrease in corticosterone secretion are responsible for its adaptogenic and memory restorative actions in chronic and chronic unpredictable stress.

  10. Free-edge stress analysis of functionally graded material layered biocomposite laminates.

    PubMed

    Huang, Bin; Kim, Heung Soo

    2014-10-01

    A stress function based theory is proposed to obtain free-edge stress distributions for three-dimensional, orthotropic, linearly elastic rectangular biocomposite laminates with surface-bonded functionally graded materials (FGM). The assumed stress fields automatically satisfy the pointwise equilibrium equation, as well as traction-free and free edge boundary conditions. The complementary virtual work principle, followed by the general eigenvalue solution procedure, is used to obtain 3-D free edge stress states. A typical stacking sequence of composite laminate is used as numerical investigation with surface bonded FGMs. It is shown that with proper exponential factor of FGMs, the interlaminar stresses at the FGM layer interface can be reduced significantly, in return to prevent debonding of FGM layers. This approach can be useful in the design of functionally graded material layered biocomposite structures.

  11. A NAP-Family Histone Chaperone Functions in Abiotic Stress Response and Adaptation1[OPEN

    PubMed Central

    Pareek, Ashwani; Singla-Pareek, Sneh Lata

    2016-01-01

    Modulation of gene expression is one of the most significant molecular mechanisms of abiotic stress response in plants. Via altering DNA accessibility, histone chaperones affect the transcriptional competence of genomic loci. However, in contrast to other factors affecting chromatin dynamics, the role of plant histone chaperones in abiotic stress response and adaptation remains elusive. Here, we studied the physiological function of a stress-responsive putative rice (Oryza sativa) histone chaperone of the NAP superfamily: OsNAPL6. We show that OsNAPL6 is a nuclear-localized H3/H4 histone chaperone capable of assembling a nucleosome-like structure. Utilizing overexpression and knockdown approaches, we found a positive correlation between OsNAPL6 expression levels and adaptation to multiple abiotic stresses. Results of comparative transcriptome profiling and promoter-recruitment studies indicate that OsNAPL6 functions during stress response via modulation of expression of various genes involved in diverse functions. For instance, we show that OsNAPL6 is recruited to OsRad51 promoter, activating its expression and leading to more efficient DNA repair and abrogation of programmed cell death under salinity and genotoxic stress conditions. These results suggest that the histone chaperone OsNAPL6 may serve a regulatory role in abiotic stress physiology possibly via modulating nucleosome dynamics at various stress-associated genomic loci. Taken together, our findings establish a hitherto unknown link between histone chaperones and abiotic stress response in plants. PMID:27342307

  12. Mitochondrial functions modulate neuroendocrine, metabolic, inflammatory, and transcriptional responses to acute psychological stress

    PubMed Central

    Picard, Martin; McManus, Meagan J.; Gray, Jason D.; Nasca, Carla; Moffat, Cynthia; Kopinski, Piotr K.; Seifert, Erin L.; McEwen, Bruce S.; Wallace, Douglas C.

    2015-01-01

    The experience of psychological stress triggers neuroendocrine, inflammatory, metabolic, and transcriptional perturbations that ultimately predispose to disease. However, the subcellular determinants of this integrated, multisystemic stress response have not been defined. Central to stress adaptation is cellular energetics, involving mitochondrial energy production and oxidative stress. We therefore hypothesized that abnormal mitochondrial functions would differentially modulate the organism’s multisystemic response to psychological stress. By mutating or deleting mitochondrial genes encoded in the mtDNA [NADH dehydrogenase 6 (ND6) and cytochrome c oxidase subunit I (COI)] or nuclear DNA [adenine nucleotide translocator 1 (ANT1) and nicotinamide nucleotide transhydrogenase (NNT)], we selectively impaired mitochondrial respiratory chain function, energy exchange, and mitochondrial redox balance in mice. The resulting impact on physiological reactivity and recovery from restraint stress were then characterized. We show that mitochondrial dysfunctions altered the hypothalamic–pituitary–adrenal axis, sympathetic adrenal–medullary activation and catecholamine levels, the inflammatory cytokine IL-6, circulating metabolites, and hippocampal gene expression responses to stress. Each mitochondrial defect generated a distinct whole-body stress-response signature. These results demonstrate the role of mitochondrial energetics and redox balance as modulators of key pathophysiological perturbations previously linked to disease. This work establishes mitochondria as stress-response modulators, with implications for understanding the mechanisms of stress pathophysiology and mitochondrial diseases. PMID:26627253

  13. Parental Family Stress during Pregnancy and Cognitive Functioning in Early Childhood: The Generation R Study

    ERIC Educational Resources Information Center

    Henrichs, Jens; Schenk, Jacqueline J.; Kok, Rianne; Ftitache, Bouchra; Schmidt, Henk G.; Hofman, Albert; Jaddoe, Vincent W. V.; Verhulst, Frank C.; Tiemeier, Henning

    2011-01-01

    We investigated whether parental family stress during pregnancy is associated with cognitive functioning in early childhood in a population-based cohort (n = 3139). Family stress was assessed using the Family Assessment Device at the 20th week of pregnancy and was reported by mothers and fathers. Mothers completed the MacArthur Communicative…

  14. Functional Play at 2 Years of Age: Effects of Prenatal Maternal Stress

    ERIC Educational Resources Information Center

    Laplante, David P.; Zelazo, Philip R.; Brunet, Alain; King, Suzanne

    2007-01-01

    Toddler toy play evolves in a predictable manner and provides a valid, nonverbal measure of cognitive function unbiased by social behaviors. Research on prenatal maternal stress (PNMS) indicates that exposure to stress in utero results in developmental deficits. We hypothesized that children exposed to high objective PNMS from a natural disaster…

  15. Angle-resolved conical emission spectra from filamentation in a solid with an Airy pattern and a Gaussian laser beam.

    PubMed

    Gong, Cheng; Li, ZiXi; Hua, LinQiang; Quan, Wei; Liu, XiaoJun

    2016-09-15

    Filamentation dynamics in fused silica are investigated using an Airy pattern and a Gaussian laser beam. The angle-resolved conical emission spectra are measured and compared with the predictions of several models. Our experimental observations are consistent with the X-waves model in both cases. This indicates that both laser beams spontaneously evolve into nonlinear X-waves and suggests a universal evolution of filaments in fused silica, regardless of the initial laser beam profile. PMID:27628383

  16. On residual stresses and homeostasis: an elastic theory of functional adaptation in living matter

    NASA Astrophysics Data System (ADS)

    Ciarletta, P.; Destrade, M.; Gower, A. L.

    2016-04-01

    Living matter can functionally adapt to external physical factors by developing internal tensions, easily revealed by cutting experiments. Nonetheless, residual stresses intrinsically have a complex spatial distribution, and destructive techniques cannot be used to identify a natural stress-free configuration. This work proposes a novel elastic theory of pre-stressed materials. Imposing physical compatibility and symmetry arguments, we define a new class of free energies explicitly depending on the internal stresses. This theory is finally applied to the study of arterial remodelling, proving its potential for the non-destructive determination of the residual tensions within biological materials.

  17. On residual stresses and homeostasis: an elastic theory of functional adaptation in living matter

    PubMed Central

    Ciarletta, P.; Destrade, M.; Gower, A. L.

    2016-01-01

    Living matter can functionally adapt to external physical factors by developing internal tensions, easily revealed by cutting experiments. Nonetheless, residual stresses intrinsically have a complex spatial distribution, and destructive techniques cannot be used to identify a natural stress-free configuration. This work proposes a novel elastic theory of pre-stressed materials. Imposing physical compatibility and symmetry arguments, we define a new class of free energies explicitly depending on the internal stresses. This theory is finally applied to the study of arterial remodelling, proving its potential for the non-destructive determination of the residual tensions within biological materials. PMID:27113413

  18. Real-time sensor mapping display for airborne imaging sensor test with the adaptive infrared imaging spectroradiometer (AIRIS)

    NASA Astrophysics Data System (ADS)

    Burton, Megan M.; Cruger, William E.; Gittins, Christopher; Kindle, Harry; Ricks, Timothy P.

    2005-11-01

    Captive flight testing (CFT) of sensors and seekers requires accurate data collection and display for sensor performance evaluation. The U.S. Army Redstone Technical Test Center (RTTC), in support of the U.S. Army Edgewood Chemical Biological Center (ECBC), has developed a data collection suite to facilitate airborne test of hyperspectral chemical/biological sensors. The data collection suite combines global positioning system (GPS) tracking, inertial measurement unit (IMU) data, accurate timing streams, and other test scenario information. This data collection suite also contains an advanced real-time display of aircraft and sensor field-of-view information. The latest evolution of this system has been used in support of the Adaptive InfraRed Imaging Spectroradiometer (AIRIS), currently under development by Physical Sciences Incorporated for ECBC. For this test, images from the AIRIS sensor were overlaid on a digitized background of the test area, with latencies of 1 second or less. Detects of surrogate chemicals were displayed and geo-referenced. Video overlay was accurate and reliable. This software suite offers great versatility in the display of imaging sensor data; support of future tests with the AIRIS sensor are planned as the system evolves.

  19. The Relationship between Stress, Fatigue, and Cognitive Functioning

    ERIC Educational Resources Information Center

    Palmer, Laura K.

    2013-01-01

    There is a plethora of research suggesting that daily stressors and fatigue can have a significant effect on learning and various cognitive functions in young adults. Little is known, however, about how these effects impact learning and other neurocognitive functions in students with learning challenges when compared to their counterparts without…

  20. The Relationship between Stress, Fatigue, and Cognitive Functioning

    ERIC Educational Resources Information Center

    Palmer, Laura K.; Economou, Peter; Cruz, Daniel; Abraham-Cook, Shannon; Huntington, Jodi S.; Maris, Marika; Makhija, Nita; Welsh, Toni; Maley, Larissa

    2014-01-01

    There is a plethora of research suggesting that daily stressors and fatigue can have a significant effect on learning and various cognitive functions in young adults. Little is known, however, about how these effects impact learning and other neurocognitive functions in students with learning challenges when compared to their counterparts without…

  1. Shear stress, reactive oxygen species, and arterial structure and function.

    PubMed

    Matlung, Hanke L; Bakker, Erik N T P; VanBavel, Ed

    2009-07-01

    Shear stress is well known to be a key factor in the regulation of small-artery tone and structure. Although nitric oxide is a major endothelium-derived factor involved in short- and long-term regulation of vascular caliber, it is clear that other mechanisms also can be involved. This review discusses the evidence for endothelium-derived reactive oxygen species (ROS) as mediators for shear-dependent arterial tone and remodeling. The work focuses on resistance vessels, because their caliber determines local perfusion. However, work on large vessels is included where needed. Attention is given to the shear-stress levels and profiles that exist in the arterial system and the differential effects of steady and oscillating shear on NO and ROS production. We furthermore address the relation between microvascular tone and remodeling and the effect of ROS and inflammation on the activity of remodeling enzymes such as matrix metalloproteinases and transglutaminases. We conclude that future work should address the role of H(2)O(2) as an endothelium-derived factor mediating tone and influencing structure of small arteries over the long term.

  2. The gall of subordination: changes in gall bladder function associated with social stress.

    PubMed Central

    Earley, Ryan L.; Blumer, Lawrence S.; Grober, Matthew S.

    2004-01-01

    Diverse physiological and behavioural mechanisms allow animals to effectively deal with stressors, but chronic activation of the stress axis can have severe consequences. We explored the effects of chronic social stress on agonistic behaviour and gall bladder function, a critical but widely neglected component of stress-induced gastrointestinal dysfunction. Prolonged cohabitation with dominant individuals elicited behavioural modifications and dramatically increased bile retention in subordinate convict cichlid fish (Archocentrus nigrofasciatum). The key predictor of gall bladder hypertrophy was social subordination rather than status-related differences in food intake or body size. Stress-induced inhibition of gall bladder emptying could affect energy assimilation such that subordinate animals would not be able to effectively convert energy-rich food into mass gain. These results parallel changes in gall bladder function preceding cholesterol gallstone formation in humans and other mammals. Thus, social stress may be an important diagnostic criterion in understanding pathologies associated with gall bladder dysfunction. PMID:15002765

  3. Plume Aerosol Size Distribution Modeling and Comparisons to PrAIRie2005 Field Study Data

    NASA Astrophysics Data System (ADS)

    Cho, S.; Liggio, J.; Makar, P.; Li, S.; Racinthe, J.

    2006-12-01

    As part of the analysis phase of the PrAIRie2005 field study, the effects of different Edmonton-area emission sources on local air-quality are being examined. Four large coal-fired power-plants are located to the West of the city. Here, the effects of these power-plants on urban and regional air-quality will be examined, using both plume and regional air-quality models. During the last few decades, coal-fired power plants have been found to be as a major source of pollution, affecting public-health. According to NACEC (North American Commission for Environmental Corporation, 2001)'s report, 46 of the top 50 air polluters in North America were power plants. The importance of such sources has resulted in several attempts to improve understanding of the basic formation mechanisms of plume particulate matter. Sulphur dioxide contributes to acidifying emissions and to the production of secondary acidic aerosols that have been linked to a number of serious human health problems, acid rain and visibility (Seinfeld and Pandis, 1998; Hidy, 1984; Wilson and McMurray, 1981). Primary particulate matter originating directly from coal-fired power plants may also increase secondary particulate mass by providing a surface for sulphuric acid absorption . Environment Canada's PrAIRie2005 field study between August 12th and September 7th, 2005 included overflights and downwind measurements near the Edmonton powerplants (Wabamun, Sundance, Keephills and Genesee). The data collected consisted of particle size distributions, ozone, NOX, total mass and the chemical composition of fine particles. In order to investigate and improve our understanding of the formation mechanisms and physical properties of power-plant-generated aerosols in the Edmonton area, the Plume Aerosol Microphysical (PAM) model has been employed. This model accounts for gas-phase chemistry, aerosol microphysical processes (i.e. homogeneous/heterogeneous nucleation, condensation/evaporation and coagulation) and

  4. Effect of Mindfulness Meditation on Perceived Stress Scores and Autonomic Function Tests of Pregnant Indian Women

    PubMed Central

    Jain, Reena; Kohli, Sangeeta; Batra, Swaraj

    2016-01-01

    Introduction Various pregnancy complications like hypertension, preeclampsia have been strongly correlated with maternal stress. One of the connecting links between pregnancy complications and maternal stress is mind-body intervention which can be part of Complementary and Alternative Medicine (CAM). Biologic measures of stress during pregnancy may get reduced by such interventions. Aim To evaluate the effect of Mindfulness meditation on perceived stress scores and autonomic function tests of pregnant Indian women. Materials and Methods Pregnant Indian women of 12 weeks gestation were randomised to two treatment groups: Test group with Mindfulness meditation and control group with their usual obstetric care. The effect of Mindfulness meditation on perceived stress scores and cardiac sympathetic functions and parasympathetic functions (Heart rate variation with respiration, lying to standing ratio, standing to lying ratio and respiratory rate) were evaluated on pregnant Indian women. Results There was a significant decrease in perceived stress scores, a significant decrease of blood pressure response to cold pressor test and a significant increase in heart rate variability in the test group (p< 0.05, significant) which indicates that mindfulness meditation is a powerful modulator of the sympathetic nervous system and can thereby reduce the day-to-day perceived stress in pregnant women. Conclusion The results of this study suggest that mindfulness meditation improves parasympathetic functions in pregnant women and is a powerful modulator of the sympathetic nervous system during pregnancy. PMID:27190795

  5. Stress, cortisol, and B lymphocytes: a novel approach to understanding academic stress and immune function.

    PubMed

    McGregor, Bonnie A; Murphy, Karly M; Albano, Denise L; Ceballos, Rachel M

    2016-01-01

    Animal and human in vitro models suggest that stress-related B lymphocyte decrements are due to high levels of glucocorticoids which cause apoptosis of pre-B-cells as they emerge from the bone marrow. The present study sought to explore the relationships among distress, salivary cortisol, and human B lymphocytes in vivo. Distress (perceived stress, negative affect, depressive symptoms), lymphocyte phenotype, and salivary cortisol were assessed among first-year graduate students (n = 22) and a community control sample (n = 30) at the start of classes in the fall and the week immediately before spring preliminary exams. Compared to controls, students reported greater distress on all measures at each time point except baseline perceived stress. Hierarchical linear regression with necessary control variables was used to assess the effect of student status on the three measures of distress, the four measures of lymphocyte phenotype, and cortisol AUC and CAR over time (T1-T2). Student status was associated with a significant decrease in CD19 + B lymphocytes and flattened cortisol awakening response (CAR). Change in CAR was associated with the decrease in CD19 + B lymphocytes. Results indicated that there are significant associations among student status, flattening of CAR, and decrements in CD19 + lymphocytes. PMID:26644211

  6. Stress, cortisol, and B lymphocytes: a novel approach to understanding academic stress and immune function.

    PubMed

    McGregor, Bonnie A; Murphy, Karly M; Albano, Denise L; Ceballos, Rachel M

    2016-01-01

    Animal and human in vitro models suggest that stress-related B lymphocyte decrements are due to high levels of glucocorticoids which cause apoptosis of pre-B-cells as they emerge from the bone marrow. The present study sought to explore the relationships among distress, salivary cortisol, and human B lymphocytes in vivo. Distress (perceived stress, negative affect, depressive symptoms), lymphocyte phenotype, and salivary cortisol were assessed among first-year graduate students (n = 22) and a community control sample (n = 30) at the start of classes in the fall and the week immediately before spring preliminary exams. Compared to controls, students reported greater distress on all measures at each time point except baseline perceived stress. Hierarchical linear regression with necessary control variables was used to assess the effect of student status on the three measures of distress, the four measures of lymphocyte phenotype, and cortisol AUC and CAR over time (T1-T2). Student status was associated with a significant decrease in CD19 + B lymphocytes and flattened cortisol awakening response (CAR). Change in CAR was associated with the decrease in CD19 + B lymphocytes. Results indicated that there are significant associations among student status, flattening of CAR, and decrements in CD19 + lymphocytes.

  7. Cardiovascular function during sustained +G/z/ stress

    NASA Technical Reports Server (NTRS)

    Erickson, H. H.; Sandler, H.; Stone, H. L.

    1976-01-01

    The development of aerospace systems capable of very high levels of positive vertical accelerators stress has created a need for a better understanding of the cardiovascular responses to acceleration. Using a canine model, the heart and cardiovascular system were instrumented to continuously measure coronary blood flow, cardiac output, left ventricular and aortic root pressure, and oxygen saturation in the aorta, coronary sinus, and right ventricle. The animals were exposed to acceleration profiles up to +6 G, 120 s at peak G; a seatback angle of 45 deg was simulated in some experiments. Radiopaque contrast medium was injected to visualize the left ventricular chamber, coronary vasculature, aorta, and branches of the aorta. The results suggest mechanisms responsible for arrhythmias which may occur, and subendocardial hemorrhage which has been reported in other animals.

  8. Evidence for Mini-Magnetospheres at four Lunar Magnetic Anomalies: Reiner-Gamma, Airy, Descartes and Crozier

    NASA Astrophysics Data System (ADS)

    Nayak, M.; Garrick-Bethell, I.; Hemingway, D.

    2014-12-01

    Lunar swirls are enigmatic high-albedo surface markings co-located with magnetic anomalies. The existence of mini-magnetospheres has been proposed as a formation mechanism, making small-scale magnetic field interactions with the solar wind of interest. Using data from the Lunar Prospector, Clementine, and Advanced Composition Explorer missions, we develop three metrics for the identification of mini-magnetospheres: 1) presence of coherent magnetism at low altitude for magnetic field measurements taken in the solar wind; 2) directional field distortions that are correlated with changes in incident solar wind azimuth; 3) intensification of total field strength. These metrics are applied to four lunar magnetic anomalies with various reflectances and magnetic field strengths, ranging from fully developed swirls (Reiner-Gamma, Airy) to diffuse albedo patches which may or may not be swirls (Descartes, Crozier). Specifically, we compare magnetic field measurements in the solar wind to source magnetization models constructed from observations in the lunar wake and Earth's magnetotail. By applying these criteria, we confirm previous findings of magnetosphere-like phenomena at Reiner-Gamma. We also find evidence of these phenomena at Descartes and Airy, and propose that mini-magnetospheres may exist here. At Airy, very large upwind distortions are observed, comparable to the length scale of the anomaly itself. At Reiner-Gamma and Descartes, this distortion is significantly smaller, yet the average field strengths are higher, implying that the scale of distortion is linked to the anomaly's field strength. Interestingly, at Crozier, the weakest anomaly considered, we do not observe this distortion. However, we do observe evidence of field intensification at high solar wind pressures (16 nPa). While Descartes and Reiner-Gamma are among the strongest anomalies on the Moon, and both exhibit magnetospheric properties, only Reiner-Gamma shows a well-developed swirl pattern

  9. Mindfulness meditation training alters stress-related amygdala resting state functional connectivity: a randomized controlled trial.

    PubMed

    Taren, Adrienne A; Gianaros, Peter J; Greco, Carol M; Lindsay, Emily K; Fairgrieve, April; Brown, Kirk Warren; Rosen, Rhonda K; Ferris, Jennifer L; Julson, Erica; Marsland, Anna L; Bursley, James K; Ramsburg, Jared; Creswell, J David

    2015-12-01

    Recent studies indicate that mindfulness meditation training interventions reduce stress and improve stress-related health outcomes, but the neural pathways for these effects are unknown. The present research evaluates whether mindfulness meditation training alters resting state functional connectivity (rsFC) of the amygdala, a region known to coordinate stress processing and physiological stress responses. We show in an initial discovery study that higher perceived stress over the past month is associated with greater bilateral amygdala-subgenual anterior cingulate cortex (sgACC) rsFC in a sample of community adults (n = 130). A follow-up, single-blind randomized controlled trial shows that a 3-day intensive mindfulness meditation training intervention (relative to a well-matched 3-day relaxation training intervention without a mindfulness component) reduced right amygdala-sgACC rsFC in a sample of stressed unemployed community adults (n = 35). Although stress may increase amygdala-sgACC rsFC, brief training in mindfulness meditation could reverse these effects. This work provides an initial indication that mindfulness meditation training promotes functional neuroplastic changes, suggesting an amygdala-sgACC pathway for stress reduction effects.

  10. Loss of melanocortin-4 receptor function attenuates HPA responses to psychological stress.

    PubMed

    Ryan, Karen K; Mul, Joram D; Clemmensen, Christoffer; Egan, Ann E; Begg, Denovan P; Halcomb, Kristen; Seeley, Randy J; Herman, James P; Ulrich-Lai, Yvonne M

    2014-04-01

    The melanocortin 4 receptor (MC4R), well-known for its role in the regulation of energy balance, is widely expressed in stress-regulatory brain regions, including the paraventricular nucleus of the hypothalamus (PVH) and the medial amygdala (MeA). In agreement with this, MC4R has been implicated in hypothalamic-pituitary-adrenocortical axis (HPA) regulation. The present work investigated the role of chronic Mc4r function to modulate basal HPA axis tone and to facilitate acute HPA responses to psychological stress, using a novel rat model with Mc4r loss-of-function. In this study, adult male rats were placed into 3 groups (n=15/group) according to genotype [wild-type (WT); heterozygous mutant (HET); and homozygous mutant (HOM)]. Basal (pre-stress) plasma adrenocorticotropic hormone (ACTH) and corticosterone were measured in the AM and PM, and the HPA axis response to restraint was assessed in the AM. Rats were perfused at 2h after restraint to assess the effect of loss of MC4R on stress-induced c-Fos immunolabeling in stress-regulatory brain regions. We find that basal (non-stress) AM and PM plasma ACTH and corticosterone showed a normal diurnal rhythm that was not altered according to genotype. Consistent with this, adrenal and thymus weights were unaffected by genotype. However, the plasma ACTH and corticosterone responses to restraint were significantly reduced by loss of MC4R function. Likewise, stress-induced c-Fos immunolabeling in both PVH and MeA was significantly reduced by loss of Mc4r function. These results support the hypothesis that endogenous MC4R signaling contributes to the HPA axis response to stress. Because MC4R plays a critical role in the regulation of energy balance, the present work suggests that it may also serve as an important communication link between brain metabolic and stress systems.

  11. Neighborhood functions alter unbalanced facilitation on a stress gradient in an alpine treeline simulation

    NASA Astrophysics Data System (ADS)

    Malanson, G. P.; Resler, L. M.

    2014-12-01

    The stress-gradient hypothesis states that individual and species competitive and facilitative effects change in relative importance or intensity along environmental gradients of stress. The importance of the number of facilitators in the neighborhood of a potential beneficiary has not been explored. Evenly distributed and stress-correlated facilitation and the increase in the intensity of facilitation with neighbors as linear, logarithmic, and unimodal functions is simulated for two species such as Pinus albicaulis and Abies lasiocarpa. The mutualism is unbalanced in that the establishment of one species is enhanced by neighbors more than the other. Compared to no facilitation or evenly distributed facilitation, the stress gradient produces more edges in the spatially advancing population, more overall intensity of facilitation, and more individuals further advanced into the area of higher stress; the more enhanced species has increased population relative to the other - to the point where they are equal. Among three neighborhood functions, little difference exists in outcomes between the linear and logarithmic functions, but the unimodal function, which shifts peak facilitation intensity to fewer neighbors, increases the above state variables more than the differences between the even and stress gradient facilitation scenarios. The unbalanced mutualism may be important at treeline ecotones where the spatial pattern becomes central to facilitation.

  12. Airy minima in the scattering of weakly bound light heavy ions

    NASA Astrophysics Data System (ADS)

    Michel, F.; Ohkubo, S.

    2005-11-01

    We reanalyze the existing 6Li + 12C elastic scattering angular distributions for incident energies ranging from a few MeV to 318 MeV within the frame of the optical model. Despite the important breakup effects expected in the scattering of such a fragile projectile, the system is found to display a surprising transparency. Indeed the barrier-wave/internal-wave decomposition of the elastic scattering amplitude reveals that a substantial part of the incident flux that penetrates the nuclear interior reemerges in the elastic channel, and typical refractive effects, like Airy minima, are clearly identified in the angular distributions. Coupled channel calculations performed on 12C(6Li,6Li')12C*(Jπ=2+,Ex=4.44 MeV) angular distributions extending through the whole angular range confirm the existence of an important internal-wave contribution in the backward hemisphere. A similar transparency is observed in other systems of this mass region, such as 7Li + 12C or 6Li + 16O. Finally, we examine recent 6He + 12C elastic scattering data obtained at 18 MeV by Milin et al. [Nucl. Phys. A730, 285 (2004)] and extending up to θc.m.≃85°, and we suggest additional measurements that could ascertain whether some transparency persists in the scattering of this radioactive projectile.

  13. Propagation properties of Airy-Gaussian vortex beams through the gradient-index medium.

    PubMed

    Zhao, Ruihuang; Deng, Fu; Yu, Weihao; Huang, Jiayao; Deng, Dongmei

    2016-06-01

    Propagation of Airy-Gaussian vortex (AiGV) beams through the gradient-index medium is investigated analytically and numerically with the transfer matrix method. Deriving the analytic expression of the AiGV beams based on the Huygens diffraction integral formula, we obtain the propagate path, intensity and phase distributions, and the Poynting vector of the first- and second-order AiGV beams, which propagate through the paraxial ABCD system. The ballistic trajectory is no longer conventional parabolic but trigonometric shapes in the gradient-index medium. Especially, the AiGV beams represent the singular behavior at the propagation path and the light intensity distribution. The phase distribution and the Poynting vector exhibit in reverse when the AiGV beams through the singularity. As the order increases, the main lobe of the AiGV beams is gradually overlapped by the vortex core. Further, the sidelobe weakens when the AiGV beams propagate nearly to the singularity. Additionally, the figure of the Poynting vector of the AiGV beams proves the direction of energy flow corresponding to the intensity distribution. The vortex of the second-order AiGV beams is larger, and the propagation velocity is faster than that of the first order. PMID:27409428

  14. Effects of stress on immune function: the good, the bad, and the beautiful.

    PubMed

    Dhabhar, Firdaus S

    2014-05-01

    Although the concept of stress has earned a bad reputation, it is important to recognize that the adaptive purpose of a physiological stress response is to promote survival during fight or flight. While long-term stress is generally harmful, short-term stress can be protective as it prepares the organism to deal with challenges. This review discusses the immune effects of biological stress responses that can be induced by psychological, physiological, or physical (including exercise) stressors. We have proposed that short-term stress is one of the nature's fundamental but under-appreciated survival mechanisms that could be clinically harnessed to enhance immunoprotection. Short-term (i.e., lasting for minutes to hours) stress experienced during immune activation enhances innate/primary and adaptive/secondary immune responses. Mechanisms of immuno-enhancement include changes in dendritic cell, neutrophil, macrophage, and lymphocyte trafficking, maturation, and function as well as local and systemic production of cytokines. In contrast, long-term stress suppresses or dysregulates innate and adaptive immune responses by altering the Type 1-Type 2 cytokine balance, inducing low-grade chronic inflammation, and suppressing numbers, trafficking, and function of immunoprotective cells. Chronic stress may also increase susceptibility to some types of cancer by suppressing Type 1 cytokines and protective T cells and increasing regulatory/suppressor T cell function. Here, we classify immune responses as being protective, pathological, or regulatory, and discuss "good" versus "bad" effects of stress on health. Thus, short-term stress can enhance the acquisition and/or expression of immunoprotective (wound healing, vaccination, anti-infectious agent, anti-tumor) or immuno-pathological (pro-inflammatory, autoimmune) responses. In contrast, chronic stress can suppress protective immune responses and/or exacerbate pathological immune responses. Studies such as the ones discussed

  15. [Personality and coping with stress in patients suffering from functional dysphonia].

    PubMed

    Freidl, W; Friedrich, G; Egger, J

    1990-01-01

    The examination covers the personality of 20 functional dysphonics, 14 individuals suffering from organic voice disorders and a group of 20 control persons when exposed to stress and its working up. In examining the group of functional dysphonics a significant positive self-assessment regarding their personality with a clear tendency to restraint has become clear. In comparison with the control persons an intensified anxiety state in situations causing stress is the result. Thus the influence of life events has been shown to have an important effect on the etiopathogenesis of functional dysphonia.

  16. Childhood poverty and stress reactivity are associated with aberrant functional connectivity in default mode network.

    PubMed

    Sripada, Rebecca K; Swain, James E; Evans, Gary W; Welsh, Robert C; Liberzon, Israel

    2014-08-01

    Convergent research suggests that childhood poverty is associated with perturbation in the stress response system. This might extend to aberrations in the connectivity of large-scale brain networks, which subserve key cognitive and emotional functions. Resting-state brain activity was measured in adults with a documented history of childhood poverty (n=26) and matched controls from middle-income families (n=26). Participants also underwent a standard laboratory social stress test and provided saliva samples for cortisol assay. Childhood poverty was associated with reduced default mode network (DMN) connectivity. This, in turn, was associated with higher cortisol levels in anticipation of social stress. These results suggest a possible brain basis for exaggerated stress sensitivity in low-income individuals. Alterations in DMN may be associated with less efficient cognitive processing or greater risk for development of stress-related psychopathology among individuals who experienced the adversity of chronic childhood poverty.

  17. Circadian Clocks and the Interaction between Stress Axis and Adipose Function

    PubMed Central

    Kolbe, Isa; Dumbell, Rebecca

    2015-01-01

    Many physiological processes and most endocrine functions show fluctuations over the course of the day. These so-called circadian rhythms are governed by an endogenous network of cellular clocks and serve as an adaptation to daily and, thus, predictable changes in the organism's environment. Circadian clocks have been described in several tissues of the stress axis and in adipose cells where they regulate the rhythmic and stimulated release of stress hormones, such as glucocorticoids, and various adipokine factors. Recent work suggests that both adipose and stress axis clock systems reciprocally influence each other and adrenal-adipose rhythms may be key players in the development and therapy of metabolic disorders. In this review, we summarize our current understanding of adrenal and adipose tissue rhythms and clocks and how they might interact to regulate energy homoeostasis and stress responses under physiological conditions. Potential chronotherapeutic strategies for the treatment of metabolic and stress disorders are discussed. PMID:26000016

  18. The Psp system of Mycobacterium tuberculosis integrates envelope stress sensing and envelope preserving functions

    PubMed Central

    Datta, Pratik; Ravi, Janani; Guerrini, Valentina; Chauhan, Rinki; Neiditch, Matthew B.; Shell, Scarlet S.; Fortune, Sarah M.; Hancioglu, Baris; Igoshin, Oleg; Gennaro, Maria Laura

    2015-01-01

    The bacterial envelope integrates essential stress-sensing and adaptive functions; thus, envelope-preserving functions are important for survival. In Gram-negative bacteria, envelope integrity during stress is maintained by the multi-gene Psp response. Mycobacterium tuberculosis was thought to lack the Psp system, since it encodes only pspA and no other psp ortholog. Intriguingly, pspA maps downstream from clgR, which encodes a transcription factor regulated by the MprAB-σE envelope-stress-signaling system. clgR inactivation lowered ATP concentration during stress and protonophore treatment-induced clgR-pspA expression, suggesting that these genes express Psp-like functions. We identified a four-gene set -- clgR, pspA (rv2744c), rv2743c, rv2742c – that is regulated by clgR and in turn regulates ClgR activity. Regulatory and protein-protein interactions within the set and a requirement of the four genes for functions associated with envelope integrity and surface-stress tolerance indicate that a Psp-like system has evolved in mycobacteria. Among Actinobacteria, the four-gene module occurred only in tuberculous mycobacteria and was required for intra-macrophage growth, suggesting links between its function and mycobacterial virulence. Additionally, the four-gene module was required for MprAB-σE stress-signaling activity. The positive feedback between envelope-stress-sensing and envelope-preserving functions allows sustained responses to multiple, envelope-perturbing signals during chronic infection, making the system uniquely suited to tuberculosis pathogenesis. PMID:25899163

  19. Endoplasmic Reticulum Stress in Intestinal Epithelial Cell Function and Inflammatory Bowel Disease

    PubMed Central

    Luo, Katherine; Cao, Stewart Siyan

    2015-01-01

    In eukaryotic cells, perturbation of protein folding homeostasis in the endoplasmic reticulum (ER) causes accumulation of unfolded and misfolded proteins in the ER lumen, which activates intracellular signaling pathways termed the unfolded protein response (UPR). Recent studies have linked ER stress and the UPR to inflammatory bowel disease (IBD). The microenvironment of the ER is affected by a myriad of intestinal luminal molecules, implicating ER stress and the UPR in proper maintenance of intestinal homeostasis. Several intestinal cell populations, including Paneth and goblet cells, require robust ER function for protein folding, maturation, and secretion. Prolonged ER stress and impaired UPR signaling may cause IBD through: (1) induction of intestinal epithelial cell apoptosis, (2) disruption of mucosal barrier function, and (3) induction of the proinflammatory response in the gut. Based on our increased understanding of ER stress in IBD, new pharmacological approaches can be developed to improve intestinal homeostasis by targeting ER protein-folding in the intestinal epithelial cells (IECs). PMID:25755668

  20. Quantum electronic stress: density-functional-theory formulation and physical manifestation.

    PubMed

    Hu, Hao; Liu, Miao; Wang, Z F; Zhu, Junyi; Wu, Dangxin; Ding, Hepeng; Liu, Zheng; Liu, Feng

    2012-08-01

    The concept of quantum electronic stress (QES) is introduced and formulated within density functional theory to elucidate extrinsic electronic effects on the stress state of solids and thin films in the absence of lattice strain. A formal expression of QES (σ(QE)) is derived in relation to deformation potential of electronic states (Ξ) and variation of electron density (Δn), σ(QE) = ΞΔn as a quantum analog of classical Hooke's law. Two distinct QES manifestations are demonstrated quantitatively by density functional theory calculations: (1) in the form of bulk stress induced by charge carriers and (2) in the form of surface stress induced by quantum confinement. Implications of QES in some physical phenomena are discussed to underlie its importance.

  1. Gene expression and functional analyses in brassinosteroid-mediated stress tolerance.

    PubMed

    Divi, Uday K; Rahman, Tawhidur; Krishna, Priti

    2016-01-01

    The plant hormone brassinosteroid (BR) plays essential roles in plant growth and development, while also controlling plant stress responses. This dual ability of BR is intriguing from a mechanistic point of view and as a viable solution for stabilizing crop yields under the changing climatic conditions. Here we report a time course analysis of BR responses under both stress and no-stress conditions, the results of which establish that BR incorporates many stress-related features even under no-stress conditions, which are then accompanied by a dynamic stress response under unfavourable conditions. Found within the BR transcriptome were distinct molecular signatures of two stress hormones, abscisic acid and jasmonic acid, which were correlated with enhanced endogenous levels of the two hormones in BR-treated seedlings. The marked presence of genes related to protein metabolism and modification, defence responses and calcium signalling highlights the significance of their associated mechanisms and roles in BR processes. Functional analysis of loss-of-function mutants of a subset of genes selected from the BR transcriptome identified abiotic stress-related roles for ACID PHOSPHATASE5 (ACP5), WRKY33, JACALIN-RELATED LECTIN1-3 (JAC-LEC1-3) and a BR-RESPONSIVE-RECEPTOR-LIKE KINASE (BRRLK). Overall, the results of this study provide a clear link between the molecular changes impacted by BR and its ability to confer broad-range stress tolerance, emphasize the importance of post-translational modification and protein turnover as BR regulatory mechanisms and demonstrate the BR transcriptome as a repertoire of new stress-related regulatory and structural genes.

  2. Effects of a novel climate on stress response and immune function in painted turtles (Chrysemys picta).

    PubMed

    Refsnider, Jeanine M; Palacios, Maria G; Reding, Dawn M; Bronikowski, Anne M

    2015-03-01

    Climate change may subject animals to increasingly stressful environmental conditions, which could have negative physiological consequences if stress levels are elevated for long periods. We conducted a manipulative experiment to determine the effects of a novel climate on stress levels and immune function in a model reptile species, the painted turtle. We collected turtles from four populations across the species' geographic range and housed them in a common-garden in one population's local climate. We measured levels of the stress hormone corticosterone and tested two aspects of innate immune function, bactericidal capacity and natural antibody agglutination, at the time of capture (baseline) and three additional time points over 1 year. The four populations did not differ in corticosterone levels over the course of 1 year, and corticosterone levels were also similar at each sampling period except that post-hibernation corticosterone levels were significantly lower than the previous three time points. Furthermore, we found no evidence that elevated corticosterone depressed immune function in the painted turtle. Our study suggests that turtles exposed to novel climatic conditions did not display a detectable stress response, nor did the novel climate depress immune function in the transplanted populations. Therefore, in terms of innate immune function, turtles may be relatively resilient to at least small changes in climatic conditions. PMID:25676021

  3. Effects of a novel climate on stress response and immune function in painted turtles (Chrysemys picta).

    PubMed

    Refsnider, Jeanine M; Palacios, Maria G; Reding, Dawn M; Bronikowski, Anne M

    2015-03-01

    Climate change may subject animals to increasingly stressful environmental conditions, which could have negative physiological consequences if stress levels are elevated for long periods. We conducted a manipulative experiment to determine the effects of a novel climate on stress levels and immune function in a model reptile species, the painted turtle. We collected turtles from four populations across the species' geographic range and housed them in a common-garden in one population's local climate. We measured levels of the stress hormone corticosterone and tested two aspects of innate immune function, bactericidal capacity and natural antibody agglutination, at the time of capture (baseline) and three additional time points over 1 year. The four populations did not differ in corticosterone levels over the course of 1 year, and corticosterone levels were also similar at each sampling period except that post-hibernation corticosterone levels were significantly lower than the previous three time points. Furthermore, we found no evidence that elevated corticosterone depressed immune function in the painted turtle. Our study suggests that turtles exposed to novel climatic conditions did not display a detectable stress response, nor did the novel climate depress immune function in the transplanted populations. Therefore, in terms of innate immune function, turtles may be relatively resilient to at least small changes in climatic conditions.

  4. The effect of surgical and psychological stress on learning and memory function in aged C57BL/6 mice.

    PubMed

    Zhang, C; Li, C; Xu, Z; Zhao, S; Li, P; Cao, J; Mi, W

    2016-04-21

    Postoperative cognitive dysfunction (POCD) is an important complication following major surgery and general anesthesia in older patients. However, the etiology of POCD remains largely to be determined. It is unknown how surgical stress and psychological stress affect the postoperative learning and memory function in geriatric patients. We therefore established a pre-clinical model in aged C57BL/6 mice and aimed to investigate the effects of surgical stress and psychological stress on learning and memory function and the possible roles of the protein kinase B/mammalian target of rapamycin (AKT/mTOR) pathway. The surgical stress was induced by abdominal surgery under local anesthesia, and the psychological stress was induced by a communication box. Cognitive functions and markers of the AKT/mTOR pathway were assessed at 1, 3 and 7 days following the stress. The impairments of learning and memory function existed for up to 7 days following surgical stress and surgical stress plus psychological stress, whereas the psychological stress did not affect the cognitive function alone or combined with surgical stress. Analysis of brain tissue revealed a significant involvement of the AKT/mTOR pathway in the impairment of cognition. These data suggested that surgical stress could induce cognitive impairment in aged mice and perioperative psychological stress is not a constitutive factor of POCD. The AKT/mTOR pathway is likely involved as one of the underlying mechanisms of the development of POCD.

  5. Similarity in the difference: changes in community functional features along natural and anthropogenic stress gradients.

    PubMed

    Gutiérrez-Cánovas, Cayetano; Sánchez-Fernández, David; Velasco, Josefa; Millan, Andrés; Bonada, Núria

    2015-09-01

    The effect of stressors on biodiversity can vary in relation to the degree to which biological communities have adapted over evolutionary time. We compared the responses of functional features of stream insect communities along chronic stress gradients with contrasting time persistence. Water salinity and land use intensification were used as examples of natural (long-term persistent) and anthropogenic (short-term persistent) stressors, respectively. A new trait-based approach was applied to quantify functional diversity components and functional redundancy within the same multidimensional space, using metrics at the taxon and community levels. We found similar functional responses along natural and anthropogenic stress gradients. In both cases, the mean taxon functional richness and functional similarity between taxa increased with stress, whereas community functional richness and functional redundancy decreased. Despite the differences in evolutionary persistence, both chronic stressors act as strong nonrandom environmental filters, producing convergent functional responses. These results can improve our ability to predict functional effects of novel stressors at ecoloiical and evolutionary scales.

  6. A biological measure of stress levels in patients with functional movement disorders

    PubMed Central

    Maurer, Carine W.; LaFaver, Kathrin; Ameli, Rezvan; Toledo, Ryan; Hallett, Mark

    2015-01-01

    Introduction While the presence of co-existing psychological stressors has historically been used as a supportive factor in the diagnosis of functional neurological disorders, many patients with functional neurological disorders deny the presence of these stressors. The stress response circuitry in these patients remains largely unexplored. Methods We performed an observational study examining biological stress levels in patients with functional movement disorders as compared with matched healthy controls. Specifically, we compared levels of circulating cortisol, the end-product of the hypothalamic-pituitary-adrenal axis. Salivary cortisol samples were collected from patients with “clinically definite” functional movement disorders (n=33) and their age- and sex-matched controls (n=33). Collections were performed at five standardized time points, reflecting participants’ diurnal cortisol cycles. To rule out confounders, participants also underwent extensive psychological assessment including Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Hamilton Anxiety Rating Scale, and Hamilton Rating Scale for Depression. Results Patients with functional movement disorders did not differ from matched controls with respect to levels of circulating cortisol. Conclusion We demonstrate that current stress levels are not altered in patients with functional movement disorders. Our results warrant careful review of current management of patients with functional neurological symptoms, and suggest that the insistence on heightened stress levels in these patients is unjustified. PMID:26117436

  7. Hypothesis: NDL proteins function in stress responses by regulating microtubule organization

    PubMed Central

    Khatri, Nisha; Mudgil, Yashwanti

    2015-01-01

    N-MYC DOWNREGULATED-LIKE proteins (NDL), members of the alpha/beta hydrolase superfamily were recently rediscovered as interactors of G-protein signaling in Arabidopsis thaliana. Although the precise molecular function of NDL proteins is still elusive, in animals these proteins play protective role in hypoxia and expression is induced by hypoxia and nickel, indicating role in stress. Homology of NDL1 with animal counterpart N-MYC DOWNREGULATED GENE (NDRG) suggests similar functions in animals and plants. It is well established that stress responses leads to the microtubule depolymerization and reorganization which is crucial for stress tolerance. NDRG is a microtubule-associated protein which mediates the microtubule organization in animals by causing acetylation and increases the stability of α-tubulin. As NDL1 is highly homologous to NDRG, involvement of NDL1 in the microtubule organization during plant stress can also be expected. Discovery of interaction of NDL with protein kinesin light chain- related 1, enodomembrane family protein 70, syntaxin-23, tubulin alpha-2 chain, as a part of G protein interactome initiative encourages us to postulate microtubule stabilizing functions for NDL family in plants. Our search for NDL interactors in G protein interactome also predicts the role of NDL proteins in abiotic stress tolerance management. Based on published report in animals and predicted interacting partners for NDL in G protein interactome lead us to hypothesize involvement of NDL in the microtubule organization during abiotic stress management in plants. PMID:26583023

  8. Proline as a stress protectant in yeast: physiological functions, metabolic regulations, and biotechnological applications.

    PubMed

    Takagi, Hiroshi

    2008-11-01

    Proline is an important amino acid in terms of its biological functions and biotechnological applications. In response to osmotic stress, proline is accumulated in many bacterial and plant cells as an osmoprotectant. However, it has been shown that proline levels are not increased under various stress conditions in the yeast Saccharomyces cerevisiae cells. Proline is believed to serve multiple functions in vitro such as protein and membrane stabilization, lowering the T (m) of DNA, and scavenging of reactive oxygen species, but the mechanisms of these functions in vivo are poorly understood. Yeast cells biosynthesize proline from glutamate in the cytoplasm via the same pathway found in bacteria and plants and also convert excess proline to glutamate in the mitochondria. Based on the fact that proline has stress-protective activity, S. cerevisiae cells that accumulate proline were constructed by disrupting the PUT1 gene involved in the degradation pathway and by expressing the mutant PRO1 gene encoding the feedback inhibition-less sensitive gamma-glutamate kinase to enhance the biosynthetic activity. The engineered yeast strains successfully showed enhanced tolerance to many stresses, including freezing, desiccation, oxidation, and ethanol. However, the appropriate cellular level and localization of proline play pivotal roles in the stress-protective effect. These results indicate that the increased stress protection is observed in yeast cells under the artificial condition of proline accumulation. Proline is expected to contribute to yeast-based industries by improving the production of frozen dough and alcoholic beverages or breakthroughs in bioethanol production. PMID:18802692

  9. Hypothesis: NDL proteins function in stress responses by regulating microtubule organization.

    PubMed

    Khatri, Nisha; Mudgil, Yashwanti

    2015-01-01

    N-MYC DOWNREGULATED-LIKE proteins (NDL), members of the alpha/beta hydrolase superfamily were recently rediscovered as interactors of G-protein signaling in Arabidopsis thaliana. Although the precise molecular function of NDL proteins is still elusive, in animals these proteins play protective role in hypoxia and expression is induced by hypoxia and nickel, indicating role in stress. Homology of NDL1 with animal counterpart N-MYC DOWNREGULATED GENE (NDRG) suggests similar functions in animals and plants. It is well established that stress responses leads to the microtubule depolymerization and reorganization which is crucial for stress tolerance. NDRG is a microtubule-associated protein which mediates the microtubule organization in animals by causing acetylation and increases the stability of α-tubulin. As NDL1 is highly homologous to NDRG, involvement of NDL1 in the microtubule organization during plant stress can also be expected. Discovery of interaction of NDL with protein kinesin light chain- related 1, enodomembrane family protein 70, syntaxin-23, tubulin alpha-2 chain, as a part of G protein interactome initiative encourages us to postulate microtubule stabilizing functions for NDL family in plants. Our search for NDL interactors in G protein interactome also predicts the role of NDL proteins in abiotic stress tolerance management. Based on published report in animals and predicted interacting partners for NDL in G protein interactome lead us to hypothesize involvement of NDL in the microtubule organization during abiotic stress management in plants.

  10. The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hyun; Gratchev, Ivan; Hein, Maw; Balasubramaniam, Arumugam

    2016-08-01

    This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton's empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.

  11. Hypothesis: NDL proteins function in stress responses by regulating microtubule organization.

    PubMed

    Khatri, Nisha; Mudgil, Yashwanti

    2015-01-01

    N-MYC DOWNREGULATED-LIKE proteins (NDL), members of the alpha/beta hydrolase superfamily were recently rediscovered as interactors of G-protein signaling in Arabidopsis thaliana. Although the precise molecular function of NDL proteins is still elusive, in animals these proteins play protective role in hypoxia and expression is induced by hypoxia and nickel, indicating role in stress. Homology of NDL1 with animal counterpart N-MYC DOWNREGULATED GENE (NDRG) suggests similar functions in animals and plants. It is well established that stress responses leads to the microtubule depolymerization and reorganization which is crucial for stress tolerance. NDRG is a microtubule-associated protein which mediates the microtubule organization in animals by causing acetylation and increases the stability of α-tubulin. As NDL1 is highly homologous to NDRG, involvement of NDL1 in the microtubule organization during plant stress can also be expected. Discovery of interaction of NDL with protein kinesin light chain- related 1, enodomembrane family protein 70, syntaxin-23, tubulin alpha-2 chain, as a part of G protein interactome initiative encourages us to postulate microtubule stabilizing functions for NDL family in plants. Our search for NDL interactors in G protein interactome also predicts the role of NDL proteins in abiotic stress tolerance management. Based on published report in animals and predicted interacting partners for NDL in G protein interactome lead us to hypothesize involvement of NDL in the microtubule organization during abiotic stress management in plants. PMID:26583023

  12. Functional Genomic Study of Exogenous n-Butanol Stress in Escherichia coli▿ † ‡

    PubMed Central

    Rutherford, Becky J.; Dahl, Robert H.; Price, Richard E.; Szmidt, Heather L.; Benke, Peter I.; Mukhopadhyay, Aindrila; Keasling, Jay D.

    2010-01-01

    n-Butanol has been proposed as an alternative biofuel to ethanol, and several industrially used microbes, including Escherichia coli, have been engineered to produce it. Unfortunately, n-butanol is more toxic than ethanol to these organisms. To understand the basis for its toxicity, cell-wide studies were conducted at the transcript, protein, and metabolite levels to obtain a global view of the n-butanol stress response. Analysis of the data indicates that n-butanol stress has components common to other stress responses, including perturbation of respiratory functions (nuo and cyo operons), oxidative stress (sodA, sodC, and yqhD), heat shock and cell envelope stress (rpoE, clpB, htpG, cpxR, and cpxP), and metabolite transport and biosynthesis (malE and opp operon). Assays using fluorescent dyes indicated a large increase in reactive oxygen species during n-butanol stress, confirming observations from the microarray and proteomics measurements. Mutant strains with mutations in several genes whose products changed most dramatically during n-butanol stress were examined for increased sensitivity to n-butanol. Results from these analyses allowed identification of key genes that were recruited to alleviate oxidative stress, protein misfolding, and other causes of growth defects. Cellular engineering based on these cues may assist in developing a high-titer, n-butanol-producing host. PMID:20118358

  13. Limbic response to psychosocial stress in schizotypy: a functional magnetic resonance imaging study.

    PubMed

    Soliman, Alexandra; O'Driscoll, Gillian A; Pruessner, Jens; Joober, Ridha; Ditto, Blaine; Streicker, Elizabeth; Goldberg, Yael; Caro, Josie; Rekkas, P Vivien; Dagher, Alain

    2011-09-01

    Psychological stress causes dopamine release in the striatum and is thought to play a role in susceptibility to psychotic illness. Previous work suggests that an elevated dopaminergic response to stress may index vulnerability to psychosis in certain individuals. With functional magnetic resonance imaging, we measured stress-induced changes in brain activity in healthy individuals at elevated risk of developing psychosis. Participants were 15 controls and 25 psychometric schizotypes: 12 with positive symptom schizotypy (perceptual aberrations) and 13 with negative symptom schizotypy (physical anhedonia), as determined by questionnaires (Chapman et al., 1976; Chapman and Chapman, 1978). In the scanner, participants performed the Montreal Imaging Stress Task and a matched sensory-motor control task. Measures of self-reported stress and salivary cortisol levels were taken throughout the experiment. All three groups showed significant increases in self-reported stress and significant fMRI signal change in the striatal, limbic and cortical regions. However, the Physical Anhedonia group showed greater stress-induced striatal and limbic deactivation than the other two groups. Deactivation in the striatum was significantly correlated with Physical Anhedonia score across all subjects. Our findings suggest the presence of abnormalities in striatal response to stress in negative symptom schizotypy.

  14. Moderators and mediators of the stress-aggression relationship: executive function and state anger.

    PubMed

    Sprague, Jenessa; Verona, Edelyn; Kalkhoff, Will; Kilmer, Ashley

    2011-02-01

    The present study examined the effects of executive function (i.e., EF) and anger/hostility on the relationship between stress (across individual stress domains, as well as at the aggregate level) and aggression. Two independent groups of participants-a college sample and a low-income community sample-were administered a battery of self-report measures concerning the subjective experience of stress, aggressive behaviors, and feelings of state anger and hostility in the last month, along with a battery of well-validated neuropsychological tests of EF. Across both samples, the stress domains that demonstrated the strongest associations with aggression were those involving chronic strains of daily living (e.g., job, financial, health) versus interpersonal stressors (e.g., family, romantic). In the community sample, analyses also revealed a significant interaction between perceived stress (aggregated across domains) and EF in predicting aggressive behavior. Specifically, participants with relatively low EF abilities, across different EF processes, showed a stronger relationship between different domains of stress and aggression in the last month. Similar effects were demonstrated in the college sample, although the interaction was not significant. In both samples, experiences of anger and hostility in the last month mediated the relationship between perceived stress (aggregate) and aggressive behavior among those low, but not high, in EF. These findings highlight the importance of higher-order cognitive processes in regulating appropriate affective and behavioral responses across different types of individuals, particularly among those experiencing high levels of stress. PMID:21401226

  15. Stress differentially impacts reserve pools and root exudation: implications for ecosystem functioning and carbon balance

    NASA Astrophysics Data System (ADS)

    Landhäusser, Simon; Karst, Justine; Wiley, Erin; Gaster, Jacob

    2016-04-01

    Environmental stress can influence carbon assimilation and the accumulation and distribution of carbon between growth, reserves, and exudation; however, it is unclear how these processes vary by different stress types. Partitioning of carbon to growth and reserves in plants might also vary between different organs. Roots reserves are of particular interest as they link the plant with the soil carbon cycle through exudation. Simple models of diffusion across concentration gradients predict the more C reserves in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by the plants. In a controlled study we tested whether different types of stresses (shade, cold soil, and drought) have differential effects on the distribution, abundance, and form (sugar vs. starch) of carbohydrates in seedlings, and whether these changes alone could explain differences in root exudation between stress types. Non-structural carbohydrate (NSC) concentration and pool sizes varied by stress type and between organs. Mass-specific C exudation increased with fine root sugar concentration; however, stress type affected exudation independently of reserve concentration. Seedlings exposed to cold soils exuded the most C on a per root mass basis followed by shade and drought. Through 13C labeling, we also found that depending on the stress type, aspen seedlings may be less able to control the loss of C to the soil compared with unstressed seedlings, resulting in more C leaked to the rhizosphere. The loss of C beyond that predicted by simple concentration gradients might have important implications for ecosystem functioning and carbon balance. If stressed plants lose proportionally more carbon to the soil, existing interactions between plants and soils may decouple under stress, and may include unexpected C fluxes between trees, soils and the atmosphere with a changing climate.

  16. Functional changes in littoral macroinvertebrate communities in response to watershed-level anthropogenic stress.

    PubMed

    Kovalenko, Katya E; Brady, Valerie J; Ciborowski, Jan J H; Ilyushkin, Sergey; Johnson, Lucinda B

    2014-01-01

    Watershed-scale anthropogenic stressors have profound effects on aquatic communities. Although several functional traits of stream macroinvertebrates change predictably in response to land development and urbanization, little is known about macroinvertebrate functional responses in lakes. We assessed functional community structure, functional diversity (Rao's quadratic entropy) and voltinism in macroinvertebrate communities sampled across the full gradient of anthropogenic stress in Laurentian Great Lakes coastal wetlands. Functional diversity and voltinism significantly decreased with increasing development, whereas agriculture had smaller or non-significant effects. Functional community structure was affected by watershed-scale development, as demonstrated by an ordination analysis followed by regression. Because functional community structure affects energy flow and ecosystem function, and functional diversity is known to have important implications for ecosystem resilience to further environmental change, these results highlight the necessity of finding ways to remediate or at least ameliorate these effects. PMID:25006811

  17. Functional Changes in Littoral Macroinvertebrate Communities in Response to Watershed-Level Anthropogenic Stress

    PubMed Central

    Kovalenko, Katya E.; Brady, Valerie J.; Ciborowski, Jan J. H.; Ilyushkin, Sergey; Johnson, Lucinda B.

    2014-01-01

    Watershed-scale anthropogenic stressors have profound effects on aquatic communities. Although several functional traits of stream macroinvertebrates change predictably in response to land development and urbanization, little is known about macroinvertebrate functional responses in lakes. We assessed functional community structure, functional diversity (Rao’s quadratic entropy) and voltinism in macroinvertebrate communities sampled across the full gradient of anthropogenic stress in Laurentian Great Lakes coastal wetlands. Functional diversity and voltinism significantly decreased with increasing development, whereas agriculture had smaller or non-significant effects. Functional community structure was affected by watershed-scale development, as demonstrated by an ordination analysis followed by regression. Because functional community structure affects energy flow and ecosystem function, and functional diversity is known to have important implications for ecosystem resilience to further environmental change, these results highlight the necessity of finding ways to remediate or at least ameliorate these effects. PMID:25006811

  18. Model-independent analysis of Airy structures in the {sup 16}O+{sup 12}C and {sup 16}O+{sup 16}O elastic scattering differential cross sections at 13-22 MeV/nucleon

    SciTech Connect

    Korda, V. Yu.; Molev, A. S.; Klepikov, V. F.; Korda, L. P.

    2009-02-15

    We present the results of the model-independent analysis of Airy structures in the {sup 16}O+{sup 12}C and {sup 16}O+{sup 16}O elastic scattering differential cross sections at 13-22 MeV/nucleon. The analysis has been performed with help of a procedure based on the application of the evolutionary algorithm, which enables us to extract the nuclear part of the scattering matrix S{sub N}(l) as a complex function of angular momentum directly from the scattering data. Contrary to the commonly used model approaches, our procedure gives the better fits and leads to the S{sub N}(l) representations defined by the moduli and the nuclear phases exhibiting smooth monotonic dependencies on l.

  19. Functional characterization of a Glycine soja Ca(2+)ATPase in salt-alkaline stress responses.

    PubMed

    Sun, Mingzhe; Jia, Bowei; Cui, Na; Wen, Yidong; Duanmu, Huizi; Yu, Qingyue; Xiao, Jialei; Sun, Xiaoli; Zhu, Yanming

    2016-03-01

    It is widely accepted that Ca(2+)ATPase family proteins play important roles in plant environmental stress responses. However, up to now, most researches are limited in the reference plants Arabidopsis and rice. The function of Ca(2+)ATPases from non-reference plants was rarely reported, especially its regulatory role in carbonate alkaline stress responses. Hence, in this study, we identified the P-type II Ca(2+)ATPase family genes in soybean genome, determined their chromosomal location and gene architecture, and analyzed their amino acid sequence and evolutionary relationship. Based on above results, we pointed out the existence of gene duplication for soybean Ca(2+)ATPases. Then, we investigated the expression profiles of the ACA subfamily genes in wild soybean (Glycine soja) under carbonate alkaline stress, and functionally characterized one representative gene GsACA1 by using transgenic alfalfa. Our results suggested that GsACA1 overexpression in alfalfa obviously increased plant tolerance to both carbonate alkaline and neutral salt stresses, as evidenced by lower levels of membrane permeability and MDA content, but higher levels of SOD activity, proline concentration and chlorophyll content under stress conditions. Taken together, for the first time, we reported a P-type II Ca(2+)ATPase from wild soybean, GsACA1, which could positively regulate plant tolerance to both carbonate alkaline and neutral salt stresses.

  20. Functionalized Stress Component onto Bio-template as a Pathway of Cytocompatibility

    PubMed Central

    Keshavarz, Meysam; Tan, Bo; Venkatakrishnan, Krishnan

    2016-01-01

    This in-vitro study introduces residual stress as a third dimension of cell stimulus to modulate the interaction between cells and bio-template, without the addition of either chemical or physical stimuli onto the bio-template surface. Ultrashort Pulsed Laser (USPL) irradiation of silicon-based bio-template causes recrystallization of silicon, which mismatches the original crystal orientation of the virgin silicon. Consequently, subsurface Induced Residual Stress (IRS) is generated. The IRS components demonstrated a strong cytocompatibility, whereas the peripheral of IRS, which is the interface between the IRS component and the virgin silicon surface, a significant directional cell alignment was observed. Fibroblast cells shown to be more sensitive to the stress component than Hela cancer cells. It revealed that cytocompatibility in terms of cell migration and directional cell alignment is directly proportional to the level of the IRS component. Higher stress level results in more cell alignment and border migration width. There is a stress threshold below which the stress component completely loses the functionality. These results pointed to a functionalized bio-template with tunable cytocompatibility. This study may lead to a new tool for the designing and engineering of bio-template. PMID:27759054

  1. [Promotion of Function of Endothelial Progenitor Cells with Shexiang Baoxin Pill Treatment under Shear Stress].

    PubMed

    Li, Gang; Chen, Yang; Wu, Jiang

    2015-08-01

    The aim of this study was to investigate whether shear stress could promote function of endothelial progenitor cells (EPCs) with Shexiang Baoxin Pill (SBP) treatment in vitro, and to study whether shear stress contributed to vascular injury repair by EPCs. EPCs were isolated and characterized; EPCs' proliferation, migration, adhesion, tube formation and eNOS protein level in vitro were investigated by culturing confluent EPCs in 4 mg/mL SBP under physiological shear stress (15 dyne/cm2) for up to 24 hours. Afterwards, EPCs were transfused into rats after wire-induced carotid artery injury augmented re-endothelialization. The results showed that, compared to the SBP group, the shear stress+SBP group obviously enhanced EPCs proliferation, migration, adhesion, tube formation and eNOS protein expression in vitro (P<0.01). After one week, immunofluorescence staining showed that endothelial regeneration rate obviously enhanced in shear stress+SBP group (P<0.01). The present study demonstrates that shear stress can promote function of endothelial progenitor cells treated with SBP, which improves the vascular injury repair potentials of EPCs. PMID:26710458

  2. Genetic variation of the weaning weight of beef cattle as a function of accumulated heat stress.

    PubMed

    Santana, M L; Bignardi, A B; Eler, J P; Ferraz, J B S

    2016-04-01

    The objective of this study was to identify the genetic variation in the weaning weight (WW) of beef cattle as a function of heat stress. The WWs were recorded at approximately 205 days of age in three Brazilian beef cattle populations: Nelore (93,616), Brangus (18,906) and Tropical Composite (62,679). In view of the cumulative nature of WW, the effect of heat stress was considered as the accumulation of temperature and humidity index units (ACTHI) from the animal's birth to weaning. A reaction norm model was used to estimate the (co)variance components of WW across the ACTHI scale. The accumulation of THI units from birth to weaning negatively affected the WW. The definition of accumulated THI units as an environmental descriptor permitted to identify important genetic variation in the WW as a function of heat stress. As evidence of genotype by environment interaction, substantial heterogeneity was observed in the (co)variance components for WW across the environmental gradient. In this respect, the best animals in less stressful environments are not necessarily the best animals in more stressful environments. Furthermore, the response to selection for WW is expected to be lower in more stressful environments.

  3. The Development of Depressive Symptoms During Medical Internship Stress Predicts Worsening Vascular Function

    PubMed Central

    Fiedorowicz, Jess G.; Ellingrod, Vicki L.; Kaplan, Mariana J.; Sen, Srijan

    2015-01-01

    Objective We sought to prospectively determine whether the onset of internship stress and any subsequent depression alters physiological markers of early vascular disease Methods We explored potential mechanisms linking stress and depression to vascular disease in a prospective cohort of 37 participants exposed to medical internship stress, an established precipitant of depressive symptomatology. Results Change in depressive symptom score from baseline over one year of internship stress was inversely correlated with change in the reactive hyperemia index (RHI), a measure of peripheral endothelial function (r=0.41, p=0.01). The change in depressive symptoms in the first six months of internship was similarly related to change in RHI over one year (r=0.38, p=0.02). While the development of depressive symptoms did not significantly impact changes in endothelial progenitor cells (EPCs), EPCs did significantly decrease with the year of internship stress (11.9 to 3.4 cells/ml blood; p=0.01). Conclusion Endothelial function may be a critical link between stress, depression, and cardiovascular disease and a feasible surrogate outcome for prospective studies. PMID:26115588

  4. Genetic variation of the weaning weight of beef cattle as a function of accumulated heat stress.

    PubMed

    Santana, M L; Bignardi, A B; Eler, J P; Ferraz, J B S

    2016-04-01

    The objective of this study was to identify the genetic variation in the weaning weight (WW) of beef cattle as a function of heat stress. The WWs were recorded at approximately 205 days of age in three Brazilian beef cattle populations: Nelore (93,616), Brangus (18,906) and Tropical Composite (62,679). In view of the cumulative nature of WW, the effect of heat stress was considered as the accumulation of temperature and humidity index units (ACTHI) from the animal's birth to weaning. A reaction norm model was used to estimate the (co)variance components of WW across the ACTHI scale. The accumulation of THI units from birth to weaning negatively affected the WW. The definition of accumulated THI units as an environmental descriptor permitted to identify important genetic variation in the WW as a function of heat stress. As evidence of genotype by environment interaction, substantial heterogeneity was observed in the (co)variance components for WW across the environmental gradient. In this respect, the best animals in less stressful environments are not necessarily the best animals in more stressful environments. Furthermore, the response to selection for WW is expected to be lower in more stressful environments. PMID:26061790

  5. [Biological function prediction of mir-210 in the liver of acute cold stress rat].

    PubMed

    Guo, Wen-Jin; Lian, Shuai; Guo, Jing-Ru; Zhai, Jun-Fei; Zhang, Yu-Chen; Li, Yue; Zhen, Li; Ji, Hong; Yang, Huan-Min

    2016-04-25

    The study was aimed to observe mir-210 expression in liver tissue of acute cold stress rat and predict the function of mir-210 in cold stress. Thirty SPF Wistar male rats which were 12-week-old and weighed (340 ± 20) g were used. The rats were pre-fed in normal room temperature for one week, and then were randomly divided into acute cold stress group at (4 ± 0.1) °C and normal control group at (24 ± 0.1) °C. After the rats were treated with cold stress for 12 h, the liver tissue was extracted and the gene expression of mir-210 was assayed using qRT-PCR. The results demonstrated that the gene expression of mir-210 was significantly enhanced in acute cold stress group compared with that in normal control group (n = 3, P < 0.01). The bioinformatics analysis showed that mir-210 has over hundreds of target genes and four kinds of target genes such as E2F3, RAD52, ISCU and Ephrin-A3 are more relative with liver cold stress. ISCU regulates the cell respiratory metabolism and Ephrin-A3 is related with cell proliferation and apoptosis. On the other hand, up-regulated mir-210 affects the DNA repairing mechanism which usually leads to genetic instabilities. Our results suggest that cold stress-induced up-regulation of mir-210 in liver harmfully influences cell growth, energy metabolism and hereditary.

  6. Surviving Endoplasmic Reticulum Stress Is Coupled to Altered Chondrocyte Differentiation and Function

    PubMed Central

    Cheslett, Deborah; Chan, Wilson C. W; So, Chi Leong; Melhado, Ian G; Chan, Tori W. Y; Kwan, Kin Ming; Hunziker, Ernst B; Yamada, Yoshihiko; Bateman, John F; Cheung, Kenneth M. C; Cheah, Kathryn S. E

    2007-01-01

    In protein folding and secretion disorders, activation of endoplasmic reticulum (ER) stress signaling (ERSS) protects cells, alleviating stress that would otherwise trigger apoptosis. Whether the stress-surviving cells resume normal function is not known. We studied the in vivo impact of ER stress in terminally differentiating hypertrophic chondrocytes (HCs) during endochondral bone formation. In transgenic mice expressing mutant collagen X as a consequence of a 13-base pair deletion in Col10a1 (13del), misfolded α1(X) chains accumulate in HCs and elicit ERSS. Histological and gene expression analyses showed that these chondrocytes survived ER stress, but terminal differentiation is interrupted, and endochondral bone formation is delayed, producing a chondrodysplasia phenotype. This altered differentiation involves cell-cycle re-entry, the re-expression of genes characteristic of a prehypertrophic-like state, and is cell-autonomous. Concomitantly, expression of Col10a1 and 13del mRNAs are reduced, and ER stress is alleviated. ERSS, abnormal chondrocyte differentiation, and altered growth plate architecture also occur in mice expressing mutant collagen II and aggrecan. Alteration of the differentiation program in chondrocytes expressing unfolded or misfolded proteins may be part of an adaptive response that facilitates survival and recovery from the ensuing ER stress. However, the altered differentiation disrupts the highly coordinated events of endochondral ossification culminating in chondrodysplasia. PMID:17298185

  7. ROCK1 functions as a critical regulator of stress erythropoiesis and survival by regulating p53

    PubMed Central

    Vemula, Sasidhar; Shi, Jianjian; Mali, Raghuveer Singh; Ma, Peilin; Liu, Yan; Hanneman, Philip; Koehler, Karl R.; Hashino, Eri; Wei, Lei

    2012-01-01

    Erythropoiesis is a dynamic, multistep process whereby hematopoietic stem cells differentiate toward a progressively committed erythroid lineage through intermediate progenitors. Although several downstream signaling molecules have been identified that regulate steady-state erythropoiesis, the major regulators under conditions of stress remain poorly defined. Rho kinases (ROCKs) belong to a family of serine/threonine kinases. Using gene-targeted ROCK1-deficient mice, we show that lack of ROCK1 in phenylhydrazine-induced oxidative stress model results in enhanced recovery from hemolytic anemia as well as enhanced splenic stress erythropoiesis compared with control mice. Deficiency of ROCK1 also results in enhanced survival, whereas wild-type mice die rapidly in response to stress. Enhanced survivability of ROCK1-deficient mice is associated with reduced level of reactive oxygen species. BM transplantation studies revealed that enhanced stress erythropoiesis in ROCK1-deficient mice is stem cell autonomous. We show that ROCK1 binds to p53 and regulates its stability and expression. In the absence of ROCK1, p53 phosphorylation and expression is significantly reduced. Our findings reveal that ROCK1 functions as a physiologic regulator of p53 under conditions of erythroid stress. These findings are expected to offer new perspectives on stress erythropoiesis and may provide a potential therapeutic target in human disease characterized by anemia. PMID:22889758

  8. Correlates of psychosomatic stress symptoms among farm women: a research note on farm and family functioning.

    PubMed

    Berkowitz, A D; Perkins, H W

    1985-01-01

    The relationship between self-reported psychosomatic stress symptoms and dimensions of family and farm functioning were examined in a sample of New York State dairy farm wives (N = 126). The farm women completed a questionnaire assessing home and farm task loads, farm complexity, intrapersonal role conflict, interpersonal role conflict, husband support, and marital satisfaction. The psychosomatic stress symptoms included nervousness, restlessness, insomnia, shortness-of-breath, and fainting. In general, stress symptoms showed little relationship to task loads, farm complexity, and intrapersonal role conflict. Much stronger relationships were found for interpersonal role conflict, husband support, and marital satisfaction. Thus, these findings point to the greater importance of family relationships in preventing or buffering stress in comparison with simple role-related task expectations of farm systems.

  9. Decreased SGK1 Expression and Function Contributes to Behavioral Deficits Induced by Traumatic Stress

    PubMed Central

    Licznerski, Pawel; Duric, Vanja; Banasr, Mounira; Alavian, Kambiz N.; Ota, Kristie T.; Kang, Hyo Jung; Jonas, Elizabeth A.; Ursano, Robert; Krystal, John H.; Duman, Ronald S.

    2015-01-01

    Exposure to extreme stress can trigger the development of major depressive disorder (MDD) as well as post-traumatic stress disorder (PTSD). The molecular mechanisms underlying the structural and functional alterations within corticolimbic brain regions, including the prefrontal cortex (PFC) and amygdala of individuals subjected to traumatic stress, remain unknown. In this study, we show that serum and glucocorticoid regulated kinase 1 (SGK1) expression is down-regulated in the postmortem PFC of PTSD subjects. Furthermore, we demonstrate that inhibition of SGK1 in the rat medial PFC results in helplessness- and anhedonic-like behaviors in rodent models. These behavioral changes are accompanied by abnormal dendritic spine morphology and synaptic dysfunction. Together, the results are consistent with the possibility that altered SGK1 signaling contributes to the behavioral and morphological phenotypes associated with traumatic stress pathophysiology. PMID:26506154

  10. Transactional relations between caregiving stress, executive functioning, and problem behavior from early childhood to early adolescence

    PubMed Central

    LaGasse, Linda L.; Conradt, Elisabeth; Karalunas, Sarah L.; Dansereau, Lynne M.; Butner, Jonathan E.; Shankaran, Seetha; Bada, Henrietta; Bauer, Charles R.; Whitaker, Toni M.; Lester, Barry M.

    2016-01-01

    Developmental psychopathologists face the difficult task of identifying the environmental conditions that may contribute to early childhood behavior problems. Highly stressed caregivers can exacerbate behavior problems, while children with behavior problems may make parenting more difficult and increase caregiver stress. Unknown is: (1) how these transactions originate, (2) whether they persist over time to contribute to the development of problem behavior and (3) what role resilience factors, such as child executive functioning, may play in mitigating the development of problem behavior. In the present study, transactional relations between caregiving stress, executive functioning, and behavior problems were examined in a sample of 1,388 children with prenatal drug exposures at three developmental time points: early childhood (birth-age 5), middle childhood (ages 6 to 9), and early adolescence (ages 10 to 13). Transactional relations differed between caregiving stress and internalizing versus externalizing behavior. Targeting executive functioning in evidence-based interventions for children with prenatal substance exposure who present with internalizing problems and treating caregiving psychopathology, depression, and parenting stress in early childhood may be particularly important for children presenting with internalizing behavior. PMID:27427803

  11. Stress and Resilience in Functional Somatic Syndromes – A Structural Equation Modeling Approach

    PubMed Central

    Fischer, Susanne; Lemmer, Gunnar; Gollwitzer, Mario; Nater, Urs M.

    2014-01-01

    Background Stress has been suggested to play a role in the development and perpetuation of functional somatic syndromes. The mechanisms of how this might occur are not clear. Purpose We propose a multi-dimensional stress model which posits that childhood trauma increases adult stress reactivity (i.e., an individual's tendency to respond strongly to stressors) and reduces resilience (e.g., the belief in one's competence). This in turn facilitates the manifestation of functional somatic syndromes via chronic stress. We tested this model cross-sectionally and prospectively. Methods Young adults participated in a web survey at two time points. Structural equation modeling was used to test our model. The final sample consisted of 3′054 participants, and 429 of these participated in the follow-up survey. Results Our proposed model fit the data in the cross-sectional (χ2(21)  = 48.808, p<.001, CFI  = .995, TLI  = .992, RMSEA  = .021, 90% CI [.013.029]) and prospective analyses (χ2(21)  = 32.675, p<.05, CFI  = .982, TLI  = .969, RMSEA  = .036, 90% CI [.001.059]). Discussion Our findings have several clinical implications, suggesting a role for stress management training in the prevention and treatment of functional somatic syndromes. PMID:25396736

  12. Acid stress mediated adaptive divergence in ion channel function during embryogenesis in Rana arvalis

    PubMed Central

    Shu, Longfei; Laurila, Anssi; Räsänen, Katja

    2015-01-01

    Ion channels and pumps are responsible for ion flux in cells, and are key mechanisms mediating cellular function. Many environmental stressors, such as salinity and acidification, are known to severely disrupt ionic balance of organisms thereby challenging fitness of natural populations. Although ion channels can have several vital functions during early life-stages (e.g. embryogenesis), it is currently not known i) how developing embryos maintain proper intracellular conditions when exposed to environmental stress and ii) to what extent environmental stress can drive intra-specific divergence in ion channels. Here we studied the moor frog, Rana arvalis, from three divergent populations to investigate the role of different ion channels and pumps for embryonic survival under acid stress (pH 4 vs 7.5) and whether populations adapted to contrasting acidities differ in the relative role of different ion channel/pumps. We found that ion channels that mediate Ca2+ influx are essential for embryonic survival under acidic pH, and, intriguingly, that populations differ in calcium channel function. Our results suggest that adaptive divergence in embryonic acid stress tolerance of amphibians may in part be mediated by Ca2+ balance. We suggest that ion flux may mediate adaptive divergence of natural populations at early life-stages in the face of environmental stress. PMID:26381453

  13. Life stress in adolescence predicts early adult reward-related brain function and alcohol dependence

    PubMed Central

    Shaw, Daniel S.; Sitnick, Stephanie L.; Musselman, Samuel C.; Forbes, Erika E.

    2015-01-01

    Stressful life events increase vulnerability to problematic alcohol use, and they may do this by disrupting reward-related neural circuitry. This is particularly relevant for adolescents because alcohol use rises sharply after mid-adolescence and alcohol abuse peaks at age 20. Adolescents also report more stressors compared with children, and neural reward circuitry may be especially vulnerable to stressors during adolescence because of prefrontal cortex remodeling. Using a large sample of male participants in a longitudinal functional magnetic resonance imaging study (N = 157), we evaluated whether cumulative stressful life events between the ages of 15 and 18 were associated with reward-related brain function and problematic alcohol use at age 20 years. Higher cumulative stressful life events during adolescence were associated with decreased response in the medial prefrontal cortex (mPFC) during monetary reward anticipation and following the receipt of monetary rewards. Stress-related decreases in mPFC response during reward anticipation and following rewarding outcomes were associated with the severity of alcohol dependence. Furthermore, mPFC response mediated the association between stressful life events and later symptoms of alcohol dependence. These data are consistent with neurobiological models of addiction that propose that stressors during adolescence increase risk for problematic alcohol use by disrupting reward circuit function. PMID:24795442

  14. Transactional relations between caregiving stress, executive functioning, and problem behavior from early childhood to early adolescence.

    PubMed

    Lagasse, Linda L; Conradt, Elisabeth; Karalunas, Sarah L; Dansereau, Lynne M; Butner, Jonathan E; Shankaran, Seetha; Bada, Henrietta; Bauer, Charles R; Whitaker, Toni M; Lester, Barry M

    2016-08-01

    Developmental psychopathologists face the difficult task of identifying the environmental conditions that may contribute to early childhood behavior problems. Highly stressed caregivers can exacerbate behavior problems, while children with behavior problems may make parenting more difficult and increase caregiver stress. Unknown is: (a) how these transactions originate, (b) whether they persist over time to contribute to the development of problem behavior and (c) what role resilience factors, such as child executive functioning, may play in mitigating the development of problem behavior. In the present study, transactional relations between caregiving stress, executive functioning, and behavior problems were examined in a sample of 1,388 children with prenatal drug exposures at three developmental time points: early childhood (birth to age 5), middle childhood (ages 6 to 9), and early adolescence (ages 10 to 13). Transactional relations differed between caregiving stress and internalizing versus externalizing behavior. Targeting executive functioning in evidence-based interventions for children with prenatal substance exposure who present with internalizing problems and treating caregiving psychopathology, depression, and parenting stress in early childhood may be particularly important for children presenting with internalizing behavior. PMID:27427803

  15. Life stress in adolescence predicts early adult reward-related brain function and alcohol dependence.

    PubMed

    Casement, Melynda D; Shaw, Daniel S; Sitnick, Stephanie L; Musselman, Samuel C; Forbes, Erika E

    2015-03-01

    Stressful life events increase vulnerability to problematic alcohol use, and they may do this by disrupting reward-related neural circuitry. This is particularly relevant for adolescents because alcohol use rises sharply after mid-adolescence and alcohol abuse peaks at age 20. Adolescents also report more stressors compared with children, and neural reward circuitry may be especially vulnerable to stressors during adolescence because of prefrontal cortex remodeling. Using a large sample of male participants in a longitudinal functional magnetic resonance imaging study (N = 157), we evaluated whether cumulative stressful life events between the ages of 15 and 18 were associated with reward-related brain function and problematic alcohol use at age 20 years. Higher cumulative stressful life events during adolescence were associated with decreased response in the medial prefrontal cortex (mPFC) during monetary reward anticipation and following the receipt of monetary rewards. Stress-related decreases in mPFC response during reward anticipation and following rewarding outcomes were associated with the severity of alcohol dependence. Furthermore, mPFC response mediated the association between stressful life events and later symptoms of alcohol dependence. These data are consistent with neurobiological models of addiction that propose that stressors during adolescence increase risk for problematic alcohol use by disrupting reward circuit function.

  16. Determination and modeling of residual stress in functionally graded WC-Co

    NASA Astrophysics Data System (ADS)

    Tahvilian, Leila

    Gradual variations in composition and/or structure through the volume of functionally graded materials (FGMs) generally result in corresponding continuous spatial variations in mechanical/physical properties, and often in significant residual stresses that develop during processing. Due to inhomogeneous properties in these materials, residual stress measurement in FGMs can be a very challenging problem. In this study, residual stresses in functionally graded cemented tungsten carbide (FG-WC-Co) were investigated by numerical, analytical and experimental approaches by means of a layer removal technique. The numerical method consisted of finite element analysis (FEA) modeling for the FGM plate, in order to calculate residual stress distribution over the volume and to develop a method for predicting residual stress levels in closely related materials. The analytical procedure embodied a mathematical approach to determine residual stress distributions, and analytically determined values are compared with those obtained from FEA modeling and experimental results. The experimental approach consisted of fabricating and heat treating FG-WC-Co flat samples, then measuring strain changes by strain gauge after each sequential layer removal from the opposite side of the specimen from the graded region. Good agreement was found between analytical, numerical and experimental results. Furthermore, thermal residual stress distribution in FG-WC-Co hollow cylinder was examined with an emphasis on the effects of key variables, the gradient profile and the gradient thickness, on the magnitude and distribution of the stress field. An analytical direct solution based on solving the governing equations of a cylinder composed of a uniform inner core and a functionally graded outer shell was developed. The cylindrical compound was considered as two separate elements: homogeneous cylinder and functionally graded shell. Material properties, such as the elastic modulus and the coefficient of

  17. Early life stress modulates amygdala-prefrontal functional connectivity: implications for oxytocin effects.

    PubMed

    Fan, Yan; Herrera-Melendez, Ana Lucia; Pestke, Karin; Feeser, Melanie; Aust, Sabine; Otte, Christian; Pruessner, Jens C; Böker, Heinz; Bajbouj, Malek; Grimm, Simone

    2014-10-01

    Recent evidence suggests that early life stress (ELS) changes stress reactivity via reduced resting state functional connectivity (rs-FC) between amygdala and the prefrontal cortex. Oxytocin (OXT) modulates amygdala connectivity and attenuates responses to psychosocial stress, but its effect appears to be moderated by ELS. Here we first investigate the effect of ELS on amygdala-prefrontal rs-FC, and examine whether ELS-associated changes of rs-FC in this neural circuit predict its response to psychosocial stress. Secondly, we explore the joint effect of OXT and ELS on the amygdala-prefrontal circuit. Eighteen healthy young males participated in a resting-state fMRI study of OXT effects using a double-blind, randomized, placebo-controlled, within-subject crossover design. We measured the rs-FC to bilateral amygdalae and subsequently assessed changes of state anxiety and prefrontal responses to psychosocial stress. Multiple linear regressions showed that ELS, specifically emotional abuse, predicted reduced rs-FC between the right amygdala and pregenual anterior cingulate cortex (pgACC), which in turn predicted elevated state anxiety after psychosocial stress. In subjects with lower ELS scores, stronger pgACC-amygdala rs-FC predicted stronger pgACC deactivation during the psychosocial stress task, and this rest-task interaction was attenuated by OXT. In subjects with higher ELS scores however, the rest-task interaction was altered and OXT showed no significant effect. These findings highlight that ELS reduces pgACC-amygdala rs-FC and alters how rs-FC of this circuit predicts its stress responsiveness. Such changes in pgACC-amygdala functional dynamics may underlie the altered sensitivity to the effects of OXT after ELS. PMID:24862297

  18. Replication stress caused by low MCM expression limits fetal erythropoiesis and hematopoietic stem cell functionality

    PubMed Central

    Alvarez, Silvia; Díaz, Marcos; Flach, Johanna; Rodriguez-Acebes, Sara; López-Contreras, Andrés J.; Martínez, Dolores; Cañamero, Marta; Fernández-Capetillo, Oscar; Isern, Joan; Passegué, Emmanuelle; Méndez, Juan

    2015-01-01

    Replicative stress during embryonic development influences ageing and predisposition to disease in adults. A protective mechanism against replicative stress is provided by the licensing of thousands of origins in G1 that are not necessarily activated in the subsequent S-phase. These ‘dormant' origins provide a backup in the presence of stalled forks and may confer flexibility to the replication program in specific cell types during differentiation, a role that has remained unexplored. Here we show, using a mouse strain with hypomorphic expression of the origin licensing factor mini-chromosome maintenance (MCM)3 that limiting origin licensing in vivo affects the functionality of hematopoietic stem cells and the differentiation of rapidly-dividing erythrocyte precursors. Mcm3-deficient erythroblasts display aberrant DNA replication patterns and fail to complete maturation, causing lethal anemia. Our results indicate that hematopoietic progenitors are particularly sensitive to replication stress, and full origin licensing ensures their correct differentiation and functionality. PMID:26456157

  19. Stem cell function and stress response are controlled by protein synthesis.

    PubMed

    Blanco, Sandra; Bandiera, Roberto; Popis, Martyna; Hussain, Shobbir; Lombard, Patrick; Aleksic, Jelena; Sajini, Abdulrahim; Tanna, Hinal; Cortés-Garrido, Rosana; Gkatza, Nikoletta; Dietmann, Sabine; Frye, Michaela

    2016-06-15

    Whether protein synthesis and cellular stress response pathways interact to control stem cell function is currently unknown. Here we show that mouse skin stem cells synthesize less protein than their immediate progenitors in vivo, even when forced to proliferate. Our analyses reveal that activation of stress response pathways drives both a global reduction of protein synthesis and altered translational programmes that together promote stem cell functions and tumorigenesis. Mechanistically, we show that inhibition of post-transcriptional cytosine-5 methylation locks tumour-initiating cells in this distinct translational inhibition programme. Paradoxically, this inhibition renders stem cells hypersensitive to cytotoxic stress, as tumour regeneration after treatment with 5-fluorouracil is blocked. Thus, stem cells must revoke translation inhibition pathways to regenerate a tissue or tumour.

  20. Stem cell function and stress response are controlled by protein synthesis.

    PubMed

    Blanco, Sandra; Bandiera, Roberto; Popis, Martyna; Hussain, Shobbir; Lombard, Patrick; Aleksic, Jelena; Sajini, Abdulrahim; Tanna, Hinal; Cortés-Garrido, Rosana; Gkatza, Nikoletta; Dietmann, Sabine; Frye, Michaela

    2016-06-16

    Whether protein synthesis and cellular stress response pathways interact to control stem cell function is currently unknown. Here we show that mouse skin stem cells synthesize less protein than their immediate progenitors in vivo, even when forced to proliferate. Our analyses reveal that activation of stress response pathways drives both a global reduction of protein synthesis and altered translational programmes that together promote stem cell functions and tumorigenesis. Mechanistically, we show that inhibition of post-transcriptional cytosine-5 methylation locks tumour-initiating cells in this distinct translational inhibition programme. Paradoxically, this inhibition renders stem cells hypersensitive to cytotoxic stress, as tumour regeneration after treatment with 5-fluorouracil is blocked. Thus, stem cells must revoke translation inhibition pathways to regenerate a tissue or tumour. PMID:27306184

  1. Systematic Analysis of Integrated Gene Functional Network of Four Chronic Stress-related Lifestyle Disorders

    PubMed Central

    Roy, Souvick; Chakraborty, Abhik; Ghosh, Chinmoy; Banerjee, Birendranath

    2015-01-01

    Background: Stress is a term used to define factors involved in changes in the physiological balances resulting in disease conditions. Chronic exposure to stress conditions in modern lifestyles has resulted in a group of disorders called lifestyle disorders. Genetic background and environmental factors are interrelated to lifestyle in determining the health status of individuals. Hence, identification of disease-associated genes is the primary step toward explanations of pathogenesis of these diseases. In functional genomics, large-scale molecular and physiological data are used for the identification of causative genes associated with a disease. Aim: The objective of our study was to find a common set of genes involved in chronic stress-related lifestyle diseases such as cardiovascular diseases (CVDs), type 2 diabetes (T2D), hypertension (HTN), and obesity. Materials and Methods: In our study, we have performed a systematic analysis of the functional gene network of four chronic stress-related lifestyle diseases by retrieving genes from published databases. We have tried to systematically construct a functional protein-protein interaction (PPI) network. The goals of establishing this network were the functional enrichment study of interacting partners as well as functional disease ontology annotation (FunDO) of the enriched genes. Results: This study enabled the identification of key genes involved in these stress-related lifestyle diseases by prioritizing candidate genes based on their degree of involvement. In this systematic analysis, we have found key genes for these diseases based on their involvement and association at the gene network level and PPI. Conclusion: We have deciphered a group of genes that in combination play a crucial role and may impact the function of the whole genome in the four lifestyle disorders mentioned. PMID:27330735

  2. Latent Classes of Adolescent Posttraumatic Stress Disorder Predict Functioning and Disorder after 1 Year

    ERIC Educational Resources Information Center

    Ayer, Lynsay; Danielson, Carla Kmett; Amstadter, Ananda B.; Ruggiero, Ken; Saunders, Ben; Kilpatrick, Dean

    2011-01-01

    Objective: To identify latent classes of posttraumatic stress disorder (PTSD) symptoms in a national sample of adolescents, and to test their associations with PTSD and functional impairment 1 year later. Method: A total of 1,119 trauma-exposed youth aged 12 through 17 years (mean = 14.99 years, 51% female and 49% male) participating in the…

  3. Grandmother Support, Family Functioning, and Parenting Stress in Families with a Child with a Disability

    ERIC Educational Resources Information Center

    Tumbarello, Natasha

    2010-01-01

    This study examined the relationship among grandparent support, family functioning, and parental stress on families with children with and without disabilities between the ages of 2 and 12 years. Families are viewed as an ever-changing complex system with reciprocal interactions. One possible stressor on the family system is the birth of a child…

  4. Family Ranching and Farming: A Consensus Management Model to Improve Family Functioning and Decrease Work Stress.

    ERIC Educational Resources Information Center

    Zimmerman, Toni Schindler; Fetsch, Robert J.

    1994-01-01

    Notes that internal and external threats could squeeze ranch and farm families out of business. Offers six-step Consensus Management Model that combines strategic planning with psychoeducation/family therapy. Describes pilot test with intergenerational ranch family that indicated improvements in family functioning, including reduced stress and…

  5. Effect of low level microwave radiation exposure on cognitive function and oxidative stress in rats.

    PubMed

    Deshmukh, Pravin Suryakantrao; Banerjee, Basu Dev; Abegaonkar, Mahesh Pandurang; Megha, Kanu; Ahmed, Rafat Sultana; Tripathi, Ashok Kumar; Mediratta, Pramod Kumari

    2013-04-01

    Use of wireless communicating devices is increasing at an exponential rate in present time and is raising serious concerns about possible adverse effects of microwave (MW) radiation emitted from these devices on human health. The present study aimed to evaluate the effects of 900 MHz MW radiation exposure on cognitive function and oxidative stress in blood of Fischer rats. Animals were divided into two groups (6 animals/group): Group I (MW-exposed) and Group II (Sham-exposed). Animals were subjected to MW exposure (Frequency 900 MHz; specific absorption rate 8.4738 x 10(-5) W/kg) in Gigahertz transverse electromagnetic cell (GTEM) for 30 days (2 h/day, 5 days/week). Subsequently, cognitive function and oxidative stress parameters were examined for each group. Results showed significant impairment in cognitive function and increase in oxidative stress, as evidenced by the increase in levels of MDA (a marker of lipid peroxidation) and protein carbonyl (a marker of protein oxidation) and unaltered GSH content in blood. Thus, the study demonstrated that low level MW radiation had significant effect on cognitive function and was also capable of leading to oxidative stress.

  6. Child Behavior Problems, Teacher Executive Functions, and Teacher Stress in Head Start Classrooms

    ERIC Educational Resources Information Center

    Friedman-Krauss, Allison H.; Raver, C. Cybele; Neuspiel, Juliana M.; Kinsel, John

    2014-01-01

    Research Findings: The current article explores the relationship between teachers' perceptions of child behavior problems and preschool teacher job stress, as well as the possibility that teachers' executive functions moderate this relationship. Data came from 69 preschool teachers in 31 early childhood classrooms in 4 Head Start centers…

  7. Emotional-volitional components of operator reliability. [sensorimotor function testing under stress

    NASA Technical Reports Server (NTRS)

    Mileryan, Y. A.

    1975-01-01

    Sensorimotor function testing in a tracking task under stressfull working conditions established a psychological characterization for a successful aviation pilot: Motivation significantly increased the reliability and effectiveness of their work. Their acitivities were aimed at suppressing weariness and the feeling of fear caused by the stress factors; they showed patience, endurance, persistence, and a capacity for lengthy volitional efforts.

  8. Early Childcare, Executive Functioning, and the Moderating Role of Early Stress Physiology

    ERIC Educational Resources Information Center

    Berry, Daniel; Willoughby, Michael T.; Blair, Clancy; Ursache, Alexandra; Granger, Douglas A.

    2014-01-01

    Intervention studies indicate that children's childcare experiences can be leveraged to support the development of executive functioning (EF). The role of more normative childcare experiences is less clear. Increasingly, theory and empirical work suggest that individual differences in children's physiological stress systems may be…

  9. Acute brief heat stress in late gestation alters neonatal calf innate immune functions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heat stress (HS), as one of the environmental stressors affecting the dairy industry, compromises the cow's milk production, immune function, and reproductive system. However, few studies have looked at how prenatal HS affects the offspring. The objective of this study was to evaluate the effect of ...

  10. Stress and Family Functioning in Parents of Girls with Rett Syndrome.

    ERIC Educational Resources Information Center

    Perry, Adrienne; And Others

    1992-01-01

    This survey of parents of 29 girls with Rett syndrome found that subjects reported more stress, lower marital satisfaction, and certain adaptations in family functioning compared to norms. However, most parents scored in the normal range. Scores were not related to socioeconomic status or characteristics of the affected child. (DB)

  11. Asymmetric Yield Function Based on the Stress Invariants for Pressure Sensitive Metals

    SciTech Connect

    Jeong Wahn Yoon; Yanshan Lou; Jong Hun Yoon; Michael V. Glazoff

    2014-05-01

    A general asymmetric yield function is proposed with dependence on the stress invariants for pressure sensitive metals. The pressure sensitivity of the proposed yield function is consistent with the experimental result of Spitzig and Richmond (1984) for steel and aluminum alloys while the asymmetry of the third invariant is preserved to model strength differential (SD) effect of pressure insensitive materials. The proposed yield function is transformed in the space of the stress triaxaility, the von Mises stress and the normalized invariant to theoretically investigate the possible reason of the SD effect. The proposed plasticity model is further extended to characterize the anisotropic behavior of metals both in tension and compression. The extension of the yield function is realized by introducing two distinct fourth-order linear transformation tensors of the stress tensor for the second and third invariants, respectively. The extended yield function reasonably models the evolution of yield surfaces for a zirconium clock-rolled plate during in-plane and through-thickness compression reported by Plunkett et al. (2007). The extended yield function is also applied to describe the orthotropic behavior of a face-centered cubic metal of AA 2008-T4 and two hexagonal close-packed metals of high-purity-titanium and AZ31 magnesium alloy. The orthotropic behavior predicted by the generalized model is compared with experimental results of these metals. The comparison validates that the proposed yield function provides sufficient predictability on SD effect and anisotropic behavior both in tension and compression. When it is necessary to consider r-value anisotropy, the proposed function is efficient to be used with nonassociated flow plasticity by introducing a separate plastic potential for the consideration of r-values as shown in Stoughton & Yoon (2004, 2009).

  12. Heating and ultraviolet light activate anti-stress gene functions in humans.

    PubMed

    Semenkov, Victor F; Michalski, Anatoli I; Sapozhnikov, Alexander M

    2015-01-01

    Different environmental factors (i.e., toxins, heavy metals, ultraviolet (UV) rays, and X-radiation) cause damage to DNA, cell membranes and other organelles and induce oxidative stress, which results in the excessive production of reactive oxygen species (ROS) by phagocytes. All types of cell stress are accompanied by the activation of anti-stress genes that can suppress ROS synthesis. We hypothesized that different environmental factors would affect organisms through the activation of anti-stress genes by autologous serum (AS) proteins, followed by the synthesis of molecules that increase cell resistance to oxidative stress. The goal of this work was to study the influence of AS on ROS production by peripheral blood neutrophils isolated from donors in different age groups. Neutrophils were isolated from 59 donors (38-94 years old). AS was heated at 100°C for 30 s. or irradiated by UV light at 200-280 nm and 8 W for 10 min. Neutrophils were exposed to heat shock at 42°C for 1 min. (short-term heating stress) or 43°C for 10 min., followed by the determination of the chemiluminescence reaction induced by zymosan. AS can increase or decrease ROS production by neutrophils depending on the structure of the proteins in the serum; these structures can be changed by heating or UV treatment and the temperature of their interaction (4 or 37°C). We propose that the effect of environmental factors on AS proteins can cause an adverse increase in oxidative stress levels due to the functional reduction of anti-stress genes. We found a negative correlation between the quantity of intracellular Hsp70 and levels of intracellular ROS production following 10 min of heat shock at 43°C. Short-term heating stress (1 min) at 42°C was followed by a prominent reduction in ROS production. This effect may be a result of the impact of the hormone adrenaline on the functions of anti-stress genes. Indeed, the same effect was observed after treatment of the neutrophils with adrenaline at

  13. Health functioning impairments associated with posttraumatic stress disorder, anxiety disorders, and depression.

    PubMed

    Zayfert, Claudia; Dums, Aricca R; Ferguson, Robert J; Hegel, Mark T

    2002-04-01

    Although anxiety disorders have been associated with impairments in self-reported health functioning, the relative effect of various anxiety disorders has not been studied. We compared health functioning of patients with a principal diagnosis of posttraumatic stress disorder (PTSD), panic disorder (PD), generalized anxiety disorder (GAD), and major depressive disorder (MDD). Patients with PTSD and MDD were equally impaired on overall mental health functioning, and both were significantly worse than patients with PD and GAD. PTSD was associated with significantly worse physical health functioning relative to PD, GAD, and MDD. Hierarchical regression showed that the association of PTSD with physical health functioning was unique and was not caused by the effects of age, depression, or comorbid anxiety disorders. Both PTSD and comorbid anxiety accounted for unique variance in mental functioning. These results highlight the association of PTSD with impaired physical and mental functioning and suggest that effective treatment of PTSD may affect overall health.

  14. Circadian clock functioning is linked to acute stress reactivity in rats.

    PubMed

    Weibel, L; Maccari, S; Van Reeth, O

    2002-10-01

    At least two major physiological systems are involved in the adaptation of the organism to environmental challenges: the circadian system and the stress reaction. This study addressed the possibility that interindividual differences in stress sensitivity and in the functioning of the circadian system are related. At 2 months of age, corticosterone secretion in response to a 20-min restraint stress was assessed in 9 Sprague-Dawley rats for which running wheel activity was recorded as a rhythmic behavioral marker of the circadian clock. Two weeks later, the adaptive response of the circadian system to an abrupt shift in the light:dark (LD) cycle was assessed in those rats using a jet-lag paradigm. Finally, after resynchronization to the new LD cycle, rats were transferred to constant darkness to assess the free-running period of their circadian rhythm of running-wheel activity. Results indicate that stress-induced corticosterone secretion was (1) positively correlated with the number of days to resynchronize the circadian activity rhythm to the new LD cycle, and with the value of its free-running period, and (2) negatively correlated with the intensity of daily locomotor activity. Those data, emphasizing the interactions between the stress response of an organism and the functioning of its circadian system, could explain interindividual differences in humans' susceptibility to shift work or other circadian-related disorders. PMID:12375620

  15. Tumor suppressor BTG1 promotes PRMT1-mediated ATF4 function in response to cellular stress

    PubMed Central

    Tijchon, Esther; van Ingen Schenau, Dorette; van Emst, Liesbeth; Levers, Marloes; Palit, Sander A.L.; Rodenbach, Caroline; Poelmans, Geert; Hoogerbrugge, Peter M.; Shan, Jixiu; Kilberg, Michael S.; Scheijen, Blanca; van Leeuwen, Frank N.

    2016-01-01

    Cancer cells are frequently exposed to physiological stress conditions such as hypoxia and nutrient limitation. Escape from stress-induced apoptosis is one of the mechanisms used by malignant cells to survive unfavorable conditions. B-cell Translocation Gene 1 (BTG1) is a tumor suppressor that is frequently deleted in acute lymphoblastic leukemia and recurrently mutated in diffuse large B cell lymphoma. Moreover, low BTG1 expression levels have been linked to poor outcome in several solid tumors. How loss of BTG1 function contributes to tumor progression is not well understood. Here, using Btg1 knockout mice, we demonstrate that loss of Btg1 provides a survival advantage to primary mouse embryonic fibroblasts (MEFs) under stress conditions. This pro-survival effect involves regulation of Activating Transcription Factor 4 (ATF4), a key mediator of cellular stress responses. We show that BTG1 interacts with ATF4 and positively modulates its activity by recruiting the protein arginine methyl transferase PRMT1 to methylate ATF4 on arginine residue 239. We further extend these findings to B-cell progenitors, by showing that loss of Btg1 expression enhances stress adaptation of mouse bone marrow-derived B cell progenitors. In conclusion, we have identified the BTG1/PRMT1 complex as a new modifier of ATF4 mediated stress responses. PMID:26657730

  16. Renal Oxidative Stress Induced by Long-Term Hyperuricemia Alters Mitochondrial Function and Maintains Systemic Hypertension

    PubMed Central

    Cristóbal-García, Magdalena; García-Arroyo, Fernando E.; Arellano-Buendía, Abraham S.; Madero, Magdalena; Rodríguez-Iturbe, Bernardo; Pedraza-Chaverrí, José; Zazueta, Cecilia; Johnson, Richard J.; Sánchez Lozada, Laura-Gabriela

    2015-01-01

    We addressed if oxidative stress in the renal cortex plays a role in the induction of hypertension and mitochondrial alterations in hyperuricemia. A second objective was to evaluate whether the long-term treatment with the antioxidant Tempol prevents renal oxidative stress, mitochondrial alterations, and systemic hypertension in this model. Long-term (11-12 weeks) and short-term (3 weeks) effects of oxonic acid induced hyperuricemia were studied in rats (OA, 750 mg/kg BW), OA+Allopurinol (AP, 150 mg/L drinking water), OA+Tempol (T, 15 mg/kg BW), or vehicle. Systolic blood pressure, renal blood flow, and vascular resistance were measured. Tubular damage (urine N-acetyl-β-D-glucosaminidase) and oxidative stress markers (lipid and protein oxidation) along with ATP levels were determined in kidney tissue. Oxygen consumption, aconitase activity, and uric acid were evaluated in isolated mitochondria from renal cortex. Short-term hyperuricemia resulted in hypertension without demonstrable renal oxidative stress or mitochondrial dysfunction. Long-term hyperuricemia induced hypertension, renal vasoconstriction, tubular damage, renal cortex oxidative stress, and mitochondrial dysfunction and decreased ATP levels. Treatments with Tempol and allopurinol prevented these alterations. Renal oxidative stress induced by hyperuricemia promoted mitochondrial functional disturbances and decreased ATP content, which represent an additional pathogenic mechanism induced by chronic hyperuricemia. Hyperuricemia-related hypertension occurs before these changes are evident. PMID:25918583

  17. Function of ABA in Stomatal Defense against Biotic and Drought Stresses.

    PubMed

    Lim, Chae Woo; Baek, Woonhee; Jung, Jangho; Kim, Jung-Hyun; Lee, Sung Chul

    2015-01-01

    The plant hormone abscisic acid (ABA) regulates many key processes involved in plant development and adaptation to biotic and abiotic stresses. Under stress conditions, plants synthesize ABA in various organs and initiate defense mechanisms, such as the regulation of stomatal aperture and expression of defense-related genes conferring resistance to environmental stresses. The regulation of stomatal opening and closure is important to pathogen defense and control of transpirational water loss. Recent studies using a combination of approaches, including genetics, physiology, and molecular biology, have contributed considerably to our understanding of ABA signal transduction. A number of proteins associated with ABA signaling and responses--especially ABA receptors--have been identified. ABA signal transduction initiates signal perception by ABA receptors and transfer via downstream proteins, including protein kinases and phosphatases. In the present review, we focus on the function of ABA in stomatal defense against biotic and abiotic stresses, through analysis of each ABA signal component and the relationships of these components in the complex network of interactions. In particular, two ABA signal pathway models in response to biotic and abiotic stress were proposed, from stress signaling to stomatal closure, involving the pyrabactin resistance (PYR)/PYR-like (PYL) or regulatory component of ABA receptor (RCAR) family proteins, 2C-type protein phosphatases, and SnRK2-type protein kinases. PMID:26154766

  18. Renal oxidative stress induced by long-term hyperuricemia alters mitochondrial function and maintains systemic hypertension.

    PubMed

    Cristóbal-García, Magdalena; García-Arroyo, Fernando E; Tapia, Edilia; Osorio, Horacio; Arellano-Buendía, Abraham S; Madero, Magdalena; Rodríguez-Iturbe, Bernardo; Pedraza-Chaverrí, José; Correa, Francisco; Zazueta, Cecilia; Johnson, Richard J; Lozada, Laura-Gabriela Sánchez

    2015-01-01

    We addressed if oxidative stress in the renal cortex plays a role in the induction of hypertension and mitochondrial alterations in hyperuricemia. A second objective was to evaluate whether the long-term treatment with the antioxidant Tempol prevents renal oxidative stress, mitochondrial alterations, and systemic hypertension in this model. Long-term (11-12 weeks) and short-term (3 weeks) effects of oxonic acid induced hyperuricemia were studied in rats (OA, 750 mg/kg BW), OA+Allopurinol (AP, 150 mg/L drinking water), OA+Tempol (T, 15 mg/kg BW), or vehicle. Systolic blood pressure, renal blood flow, and vascular resistance were measured. Tubular damage (urine N-acetyl-β-D-glucosaminidase) and oxidative stress markers (lipid and protein oxidation) along with ATP levels were determined in kidney tissue. Oxygen consumption, aconitase activity, and uric acid were evaluated in isolated mitochondria from renal cortex. Short-term hyperuricemia resulted in hypertension without demonstrable renal oxidative stress or mitochondrial dysfunction. Long-term hyperuricemia induced hypertension, renal vasoconstriction, tubular damage, renal cortex oxidative stress, and mitochondrial dysfunction and decreased ATP levels. Treatments with Tempol and allopurinol prevented these alterations. Renal oxidative stress induced by hyperuricemia promoted mitochondrial functional disturbances and decreased ATP content, which represent an additional pathogenic mechanism induced by chronic hyperuricemia. Hyperuricemia-related hypertension occurs before these changes are evident.

  19. [Effects of exogenous spermidine on mitochondrial function of tomato seedling roots under salinity-alkalinity stress].

    PubMed

    Pan, Xiong-bo; Xiang, Li-xia; Hu, Xiao-hui; Ren, Wen-qi; Zhang, Li; Ni, Xin-xin

    2016-02-01

    Two cultivars of tomato (Solanum lycopersicum, cvs. 'Jinpengchaoguan' and 'Zhongza No. 9', with the former being more tolerant to saline-alkaline stress) seedlings grown hydroponically were subjected to salinity-alkalinity stress condition (NaCl: Na2SO4:NaHCO3:Na2CO3 = 1:9:9:1) without or with foliar application of 0.25 mmol . L-1 spermidine (Spd), and the root morphology and physiological characteristics of mitochondrial membrane were analyzed 8 days after treatment, to explore the protective effects of exogenous Spd on mitochondrial function in tomato roots under salinity-alkalinity stress. The results showed that the salinity-alkalinity stress increased the concentrations of both mitochondrial H2O2 and MDA as well as the mitochondrial membrane permeability in the roots of the two cultivars, while it decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity, which impaired the mitochondria and therefore inhibited the root growth; and these effects were more obvious in 'Zhongza No. 9' than in 'Jinpengechaoguan'. Under the salinity-alkalinity stress, foliar application Spd could effectively decrease the concentrations of mitochondrial H2O2 and MDA and mitochondrial membrane permeability, while increased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity. These results suggested that exogenous Spd could effectively mitigate the damage on mitochondria induced by salinity-alkalinity stress, and the alleviation effect was more obvious in 'Zhongza No. 9' than in 'Jinpengchaoguan'.

  20. Function of ABA in Stomatal Defense against Biotic and Drought Stresses

    PubMed Central

    Lim, Chae Woo; Baek, Woonhee; Jung, Jangho; Kim, Jung-Hyun; Lee, Sung Chul

    2015-01-01

    The plant hormone abscisic acid (ABA) regulates many key processes involved in plant development and adaptation to biotic and abiotic stresses. Under stress conditions, plants synthesize ABA in various organs and initiate defense mechanisms, such as the regulation of stomatal aperture and expression of defense-related genes conferring resistance to environmental stresses. The regulation of stomatal opening and closure is important to pathogen defense and control of transpirational water loss. Recent studies using a combination of approaches, including genetics, physiology, and molecular biology, have contributed considerably to our understanding of ABA signal transduction. A number of proteins associated with ABA signaling and responses—especially ABA receptors—have been identified. ABA signal transduction initiates signal perception by ABA receptors and transfer via downstream proteins, including protein kinases and phosphatases. In the present review, we focus on the function of ABA in stomatal defense against biotic and abiotic stresses, through analysis of each ABA signal component and the relationships of these components in the complex network of interactions. In particular, two ABA signal pathway models in response to biotic and abiotic stress were proposed, from stress signaling to stomatal closure, involving the pyrabactin resistance (PYR)/PYR-like (PYL) or regulatory component of ABA receptor (RCAR) family proteins, 2C-type protein phosphatases, and SnRK2-type protein kinases. PMID:26154766

  1. Physiological functions of glucocorticoids in stress and their relation to pharmacological actions.

    PubMed

    Munck, A; Guyre, P M; Holbrook, N J

    1984-01-01

    Almost any kind of threat to homeostasis or stress will cause plasma glucocorticoid levels to rise. The increased levels have traditionally been ascribed the physiological function of enhancing the organism's resistance to stress, a role well recognized in glucocorticoid therapy. How the known physiological and pharmacological effects of glucocorticoids might accomplish this function, however, remains a mystery. A generalization that is beginning to emerge is that many of these effects may be secondary to modulation by glucocorticoids of the actions of numerous intercellular mediators, including established hormones, prostaglandins and other arachidonic acid metabolites, certain secreted neutral proteinases, lymphokines, and a variety of bioactive peptides. These mediators participate in physiological mechanisms--endocrine, renal, immune, neural, etc.--that mount a first line of defense against such challenges to homeostasis as hemorrhage, metabolic disturbances, infection, anxiety, and others. Contrary to the traditional view that glucocorticoids enhance these defense mechanisms, however, it has become increasingly clear that glucocorticoids at moderate to high levels generally suppress them. This paradox, which first emerged when glucocorticoids were discovered to be antiinflammatory agents, remains a major obstacle to a unified picture of glucocorticoid function. We propose that stress-induced increases in glucocorticoid levels protect not against the source of stress itself but rather against the body's normal reactions to stress, preventing those reactions from overshooting and themselves threatening homeostasis. This hypothesis, the seeds of which are to be found in many discussions of particular glucocorticoid effects, immediately accounts for the paradox noted above. Furthermore, it provides glucocorticoid physiology with a unified conceptual framework that can accommodate such apparently unrelated physiological and pharmacological effects as those on

  2. Stress during pregnancy affects general intellectual and language functioning in human toddlers.

    PubMed

    Laplante, David P; Barr, Ronald G; Brunet, Alain; Galbaud du Fort, Guillaume; Meaney, Michael L; Saucier, Jean-Francois; Zelazo, Philip R; King, Suzanne

    2004-09-01

    Prenatal maternal stress has been shown to impair functioning in nonhuman primate offspring. Little is known about the effects of prenatal stress on intellectual and language development in humans because it is difficult to identify sufficiently large samples of pregnant women who have been exposed to an independent stressor. We took advantage of a natural disaster (January 1998 ice storm in Québec, Canada) to determine the effect of the objective severity of pregnant women's stress exposure on general intellectual and language development of their children. Bayley Mental Development Index (MDI) scores and parent-reported language abilities of 58 toddlers of mothers who were exposed to varying levels of prenatal stress were obtained at 2 y of age. The hierarchical multiple regression analyses indicated that the toddlers' birth weight and age at testing accounted for 12.0% and 14.8% of the variance in the Bayley MDI scores and in productive language abilities, respectively. More importantly, the level of prenatal stress exposure accounted for an additional 11.4% and 12.1% of the variance in the toddlers' Bayley MDI and productive language abilities and uniquely accounted for 17.3% of the variance of their receptive language abilities. The more severe the level of prenatal stress exposure, the poorer the toddlers' abilities. The level of prenatal stress exposure accounted for a significant proportion of the variance in the three dependent variables above and beyond that already accounted for by non-ice storm-related factors. We suspect that high levels of prenatal stress exposure, particularly early in the pregnancy, may negatively affect the brain development of the fetus, reflected in the lower general intellectual and language abilities in the toddlers.

  3. Parents of children with haemophilia at an early age: assessment of perceived stress and family functioning.

    PubMed

    Torres-Ortuño, A; Cuesta-Barriuso, R; Nieto-Munuera, J

    2014-11-01

    Haemophilia is a chronic disease that requires a multidisciplinary approach for proper management and control of its clinical manifestations. The perception and management of parents of children with haemophilia can be affected by stressful situations as a result of treatment or disease progression. The aim of this study was to evaluate the perception of stress and family functioning in parents of children with haemophilia 1-7 years. This is an observational clinical study involving 49 parents of children with haemophilia 1-7 years who attended the VIII Workshop for Parents of Children with haemophilia, organized by the Spanish Federation of Hemophilia in La Charca, Murcia (Spain). After obtaining parental consent, the questionnaires was applied to them, FACES III (family functioning) and Pediatric Inventory for Parents (perceived stress), and a record of data on the clinical characteristics and treatment. Significant differences in the perception of stressors by gender of parents were found. A family history of haemophilia, the use of port-a-cath, inhibitor development and gender of the parents were the descriptive variables most correlated with dependents variables. These variables, together with the type of haemophilia affect significantly in the parental stress and family functioning. Parents have difficulty adjusting to disease management, perceiving many stressors. Gender and family history, can hinder the proper compliance with treatments, reducing its effectiveness.

  4. Hal2p functions in Bdf1p-involved salt stress response in Saccharomyces cerevisiae.

    PubMed

    Chen, Lei; Liu, Liangyu; Wang, Mingpeng; Fu, Jiafang; Zhang, Zhaojie; Hou, Jin; Bao, Xiaoming

    2013-01-01

    The Saccharomyces cerevisiae Bdf1p associates with the basal transcription complexes TFIID and acts as a transcriptional regulator. Lack of Bdf1p is salt sensitive and displays abnormal mitochondrial function. The nucleotidase Hal2p detoxifies the toxic compound 3' -phosphoadenosine-5'-phosphate (pAp), which blocks the biosynthesis of methionine. Hal2p is also a target of high concentration of Na(+). Here, we reported that HAL2 overexpression recovered the salt stress sensitivity of bdf1Δ. Further evidence demonstrated that HAL2 expression was regulated indirectly by Bdf1p. The salt stress response mechanisms mediated by Bdf1p and Hal2p were different. Unlike hal2Δ, high Na(+) or Li(+) stress did not cause pAp accumulation in bdf1Δ and methionine supplementation did not recover its salt sensitivity. HAL2 overexpression in bdf1Δ reduced ROS level and improved mitochondrial function, but not respiration. Further analyses suggested that autophagy was apparently defective in bdf1Δ, and autophagy stimulated by Hal2p may play an important role in recovering mitochondrial functions and Na(+) sensitivity of bdf1Δ. Our findings shed new light towards our understanding about the molecular mechanism of Bdf1p-involved salt stress response in budding yeast.

  5. Antenatal Maternal Stress Alters Functional Brain Responses In Adult Offspring During Conditioned Fear

    PubMed Central

    Sadler, Theodore R.; Nguyen, Peter T.; Yang, Jun; Givrad, Tina K.; Mayer, Emeran A.; Maarek, Jean-Michel I.; Hinton, David R.; Holschneider, Daniel P.

    2011-01-01

    Antenatal maternal stress has been shown in rodent models and in humans to result in altered behavioral and neuroendocrine responses, yet little is known about its effects on functional brain activation. Pregnant female rats received a daily foot-shock stress or sham-stress two days after testing plug-positive and continuing for the duration of their pregnancy. Adult male offspring (age 14 weeks) with and without prior maternal stress (MS) were exposed to an auditory fear conditioning (CF) paradigm. Cerebral blood flow (CBF) was assessed during recall of the tone cue in the nonsedated, nontethered animal using the 14C-iodoantipyrine method, in which the tracer was administered intravenously by remote activation of an implantable minipump. Regional CBF distribution was examined by autoradiography and analyzed by statistical parametric mapping in the three-dimensionally reconstructed brains. Presence of fear memory was confirmed by behavioral immobility (‘freezing’). Corticosterone plasma levels during the CF paradigm were measured by ELISA in a separate group of rats. Antenatal MS exposure altered functional brain responses to the fear conditioned cue in adult offspring. Rats with prior MS exposure compared to those without demonstrated heightened fear responsivity, exaggerated and prolonged corticosterone release, increased functional cerebral activation of limbic/paralimbic regions (amygdala, ventral hippocampus, insula, ventral striatum, nucleus acumbens), the locus coeruleus, and white matter, and deactivation of medial prefrontal cortical regions. Dysregulation of corticolimbic circuits may represent risk factors in the future development of anxiety disorders and associated alterations in emotional regulation. PMID:21300034

  6. Stress and Drug Dependence Differentially Modulate Norepinephrine Signaling in Animals with Varied HPA Axis Function

    PubMed Central

    Fox, Megan E; Studebaker, R Isaac; Swofford, Nathaniel J; Wightman, R Mark

    2015-01-01

    Previous work has demonstrated the importance of genetic factors and stress-sensitive circuits in the development of affective disorders. Anxiety and numerous psychological disorders are comorbid with substance abuse, and noradrenergic signaling in the bed nucleus of the stria terminalis (BNST) is thought to be a source of this convergence. Here, we examined the effects of different stressors on behavior and norepinephrine dynamics in the BNST of rat strains known to differ in their HPA-axis function. We compared the effects of acute morphine dependence and social isolation in non-anxious Sprague Dawley (SD) rats, and a depression model, Wistar-Kyoto (WKY) rats. We found a shared phenotype in drug-dependent and singly housed SD rats, characterized by slowed norepinephrine clearance, decreased autoreceptor function, and elevated anxiety. WKY rats exhibited changes in anxiety and autoreceptor function only following morphine dependence. To ascertain the influence of LC inhibition on this plasticity, we administered the LC-terminal-selective toxin DSP-4 to SD and WKY rats. DSP-4-treated SD rats demonstrated a dependence-like phenotype, whereas WKY rats were unchanged. Overall, our findings suggest that individuals with varying stress susceptibilities have different noradrenergic signaling changes in response to stress. These changes may establish conditions that favor stress-induced reinstatement and increase the risk for addiction. PMID:25601230

  7. Posttraumatic Stress Disorder Symptoms and Social and Occupational Functioning of People With Schizophrenia.

    PubMed

    Ng, Lauren C; Petruzzi, Liana J; Greene, M Claire; Mueser, Kim T; Borba, Christina P C; Henderson, David C

    2016-08-01

    This study sought to clarify the contribution of posttraumatic stress disorder (PTSD) to interpersonal and occupational functioning in people with schizophrenia. Self-report questionnaires and semistructured interviews were used to evaluate PTSD and brain injury, positive symptoms, depression, substance abuse, occupational and social functioning, and intelligence. Multiple regressions assessed the relationship between predictors and functional impairment. Posttraumatic stress disorder symptoms were present in 76% of participants, with 12% of participants meeting diagnostic criteria for PTSD. Participants with PTSD had higher rates of depression and more severe positive symptoms. Results of multiple regressions indicated that PTSD symptoms were the only significant predictor of patient-rated interpersonal and occupational functioning. Posttraumatic stress disorder symptoms were not associated with interviewer-rated interpersonal or occupational functioning or employment. While more research is needed, screening and treatment for exposure to traumatic events and PTSD symptoms might be indicated for individuals with schizophrenia. Availability of PTSD assessment and evidence-based treatments for people with schizophrenia is a crucial and often unmet health service need. PMID:27105458

  8. The aftermath of terrorism: posttraumatic stress and functional impairment after the 2011 Oslo bombing

    PubMed Central

    Solberg, Øivind; Blix, Ines; Heir, Trond

    2015-01-01

    Objective: In the present study we wanted to investigate the link between exposure, posttraumatic stress symptomatology, and functional impairment in the aftermath of terrorism. Method: Posttraumatic stress symptomatology and functional impairment related to the Oslo bombing 22nd of July, 2011, in directly and indirectly exposed individuals (N = 1927) were assessed together with demographics, exposure, peri-traumatic reactions, and event centrality approximately 1 year after the attack. Results: Directly and indirectly exposed individuals qualifying for posttraumatic stress disorder (PTSD) reported similar peri-traumatic reactions, event centrality, and functional impairment. However, clusters within the PTSD symptomatology were differentially associated with impairment as a function of their exposure. In the directly exposed group, all clusters within the PTSD symptomatology were associated with impairment in function, while only emotional numbing was associated with impairment within the indirectly exposed group. Conclusion: Considering that terror attacks frequently involve directly exposed individuals and a larger population of indirectly exposed individuals, this finding is of importance, especially in the design of intervention programs and the development of treatment policies. PMID:26300833

  9. Residual stress impairs pump function after surgical ventricular remodeling: A finite element analysis

    PubMed Central

    Pantoja, Joe Luis; Zhang, Zhihong; Tartibi, Mehrzad; Sun, Kay; Macmillan, Warrick; Guccione, Julius M.; Ge, Liang; Ratcliffe, Mark B.

    2016-01-01

    Objectives Surgical ventricular restoration (Dor procedure) is generally thought to reduce left ventricular (LV) myofiber stress (FS) but to adversely affect pump function. However, the underlying mechanism is unclear. The goal of this study was to determine the effect of residual stress (RS) on LV FS and pump function after the Dor procedure. Methods Previously described finite element models of the LV based on MRI data obtained in five sheep 16 weeks after antero-apical myocardial infarction were used. Simulated Dacron patches that were elliptical and 25% of the infarct opening area were implanted using a virtual suture technique (VIRTUAL-DOR). In each case, diastole and systole were simulated and RS, FS, LV volumes, systolic and diastolic function, and pump (Starling) function were calculated. Results VIRTUAL-DOR was associated with significant RS that was tensile (2.89±1.31 kPa) in the remote myocardium and compressive (234.15±65.53 kPa) in the borderzone (BZ). VIRTUAL-DOR+RS (compared to VIRTUAL-DOR-NO-RS) was associated with further reduction in regional diastolic and systolic FS with the greatest change in the BZ (43.5-fold and 7.1-fold respectively, p<0.0001). VIRTUAL-DOR+RS was also associated with further reduction in systolic and diastolic volumes (7.9%, p=0.0606 and 10.6%, p=0.0630, respectively). The resultant effect was a further reduction in pump function after VIRTUAL-DOR+RS. Conclusion Residual stress that occurs after the Dor procedure is positive (tensile) in the remote myocardium and negative (compressive) in the BZ and associated with reductions in fiber stress and LV volumes. The resultant effect is a further reduction in LV pump (Starling) function. PMID:26341601

  10. The Relationship between Stress and Social Functioning in Adults with Autism Spectrum Disorder and without Intellectual Disability

    PubMed Central

    Bishop-Fitzpatrick, Lauren; Mazefsky, Carla A.; Minshew, Nancy J.; Eack, Shaun M.

    2014-01-01

    Scientific Abstract Adults with autism spectrum disorder (ASD) face substantial challenges accomplishing basic tasks associated with daily living, which are exacerbated by their broad and pervasive difficulties with social interactions. These challenges put people with ASD at increased risk for psychophysiological distress, which likely factors heavily into social functioning for adults with ASD, as suggested by a growing literature on stress in children that indicates that children with ASD have differential responses to stress than healthy children. We hypothesized that adults with ASD and without intellectual disability (n=38) would experience more stress than healthy volunteers (n=37) and that there would be an inverse relationship between stress and social functioning in individuals with ASD. Baseline, semi-structured interview data from a randomized-controlled trial of two treatments for adults with ASD were used to assess differences in stress between adults with ASD and healthy volunteers and to assess the relationship between stress response and social functioning in adults with ASD. Findings indicate that adults with ASD experience greater perceived and interviewer-observed stress than did healthy volunteers and that stress is significantly related to social functioning in adults with ASD. These findings highlight the role of stress in adult functioning and outcomes and suggest the need to develop and assess treatments designed to target stress and coping in adults with ASD. PMID:25524571

  11. Stress

    MedlinePlus

    ... hurt or killed. Examples include a major accident, war, assault, or a natural disaster. This type of ... stress, so you can avoid more serious health effects. NIH: National Institute of Mental Health

  12. The Conserved SKN-1/Nrf2 Stress Response Pathway Regulates Synaptic Function in Caenorhabditis elegans

    PubMed Central

    Staab, Trisha A.; Griffen, Trevor C.; Corcoran, Connor; Evgrafov, Oleg; Knowles, James A.; Sieburth, Derek

    2013-01-01

    The Nrf family of transcription factors plays a critical role in mediating adaptive responses to cellular stress and defends against neurodegeneration, aging, and cancer. Here, we report a novel role for the Caenorhabditis elegans Nrf homolog SKN-1 in regulating synaptic transmission at neuromuscular junctions (NMJs). Activation of SKN-1, either by acute pharmacological treatment with the mitochondrial toxin sodium arsenite or by mutations that cause constitutive SKN-1 activation, results in defects in neuromuscular function. Additionally, elimination of the conserved WD40 repeat protein WDR-23, a principal negative regulator of SKN-1, results in impaired locomotion and synaptic vesicle and neuropeptide release from cholinergic motor axons. Mutations that abolish skn-1 activity restore normal neuromuscular function to wdr-23 mutants and animals treated with toxin. We show that negative regulation of SKN-1 by WDR-23 in the intestine, but not at neuromuscular junctions, is necessary and sufficient for proper neuromuscular function. WDR-23 isoforms differentially localize to the outer membranes of mitochondria and to nuclei, and the effects of WDR-23 on neuromuscular function are dependent on its interaction with cullin E3 ubiquitin ligase. Finally, whole-transcriptome RNA sequencing of wdr-23 mutants reveals an increase in the expression of known SKN-1/Nrf2-regulated stress-response genes, as well as neurotransmission genes not previously implicated in SKN-1/Nrf2 responses. Together, our results indicate that SKN-1/Nrf2 activation may be a mechanism through which cellular stress, detected in one tissue, affects cellular function of a distal tissue through endocrine signaling. These results provide insight into how SKN-1/Nrf2 might protect the nervous system from damage in response to oxidative stress. PMID:23555279

  13. Gene mining in halophytes: functional identification of stress tolerance genes in Lepidium crassifolium.

    PubMed

    Rigó, Gábor; Valkai, Ildikó; Faragó, Dóra; Kiss, Edina; Van Houdt, Sara; Van de Steene, Nancy; Hannah, Matthew A; Szabados, László

    2016-09-01

    Extremophile plants are valuable sources of genes conferring tolerance traits, which can be explored to improve stress tolerance of crops. Lepidium crassifolium is a halophytic relative of the model plant Arabidopsis thaliana, and displays tolerance to salt, osmotic and oxidative stresses. We have employed the modified Conditional cDNA Overexpression System to transfer a cDNA library from L. crassifolium to the glycophyte A. thaliana. By screening for salt, osmotic and oxidative stress tolerance through in vitro growth assays and non-destructive chlorophyll fluorescence imaging, 20 Arabidopsis lines were identified with superior performance under restrictive conditions. Several cDNA inserts were cloned and confirmed to be responsible for the enhanced tolerance by analysing independent transgenic lines. Examples include full-length cDNAs encoding proteins with high homologies to GDSL-lipase/esterase or acyl CoA-binding protein or proteins without known function, which could confer tolerance to one or several stress conditions. Our results confirm that random gene transfer from stress tolerant to sensitive plant species is a valuable tool to discover novel genes with potential for biotechnological applications. PMID:27343166

  14. Conserved cellular function and stress-mediated regulation among members of the proteolipid protein family.

    PubMed

    Fernández, María E; Alfonso, Julieta; Brocco, Marcela A; Frasch, Alberto C

    2010-05-01

    Chronic stress causes morphological alterations in the hippocampus of rodents and tree shrews, including atrophy of CA3 dendrites and loss of synapses. The molecular mechanisms underlying these structural changes remain largely unknown. We have previously identified M6a as a stress responsive gene and shown that M6a is involved in filopodium/spine outgrowth and, likely, synapse formation. M6a belongs to the proteolipid protein (PLP) family, all of their members having four transmembrane domains that allow their localization at the plasma membrane. In the present work, we analyzed other members of this family, the closely related M6b as well as PLP and its splice variant DM20. We found that chronic restraint stress in mice reduces M6b and DM20, but not PLP, mRNA levels in the hippocampus. In addition, M6b and DM20, but again not PLP, induce filopodium formation in primary cultures of hippocampal neurons. Several M6b protein isoforms were studied, all of them having similar effects except for the one lacking the transmembrane domains. Our results reveal a conserved cellular function and a stress-mediated regulation among members of the proteolipid protein family, suggesting an involvement of proteolipid proteins in the stress response. PMID:19937804

  15. Development of accumulated heat stress index based on time-weighted function

    NASA Astrophysics Data System (ADS)

    Lee, Ji-Sun; Byun, Hi-Ryong; Kim, Do-Woo

    2016-05-01

    Heat stress accumulates in the human body when a person is exposed to a thermal condition for a long time. Considering this fact, we have defined the accumulated heat stress (AH) and have developed the accumulated heat stress index (AHI) to quantify the strength of heat stress. AH represents the heat stress accumulated in a 72-h period calculated by the use of a time-weighted function, and the AHI is a standardized index developed by the use of an equiprobability transformation (from a fitted Weibull distribution to the standard normal distribution). To verify the advantage offered by the AHI, it was compared with four thermal indices the humidex, the heat index, the wet-bulb globe temperature, and the perceived temperature used by national governments. AH and the AHI were found to provide better detection of thermal danger and were more useful than other indices. In particular, AH and the AHI detect deaths that were caused not only by extremely hot and humid weather, but also by the persistence of moderately hot and humid weather (for example, consecutive daily maximum temperatures of 28-32 °C), which the other indices fail to detect.

  16. Genetic variation in cortico-amygdala serotonin function and risk for stress-related disease

    PubMed Central

    Holmes, Andrew

    2008-01-01

    The serotonin system is strongly implicated in the pathophysiology and therapeutic alleviation of stress-related disorders such as anxiety and depression. Serotonergic modulation of the acute response to stress and the adaptation to chronic stress is mediated by a myriad of molecules controlling serotonin neuron development (Pet-1), synthesis (tryptophan hydroxylase 1 and 2 isozymes), packaging (vesicular monoamine transporter 2), actions at presynaptic and postsynaptic receptors (5-HT1A, 5-HT1B, 5-HT2A, 5-HT2C, 5-HT3A, 5-HT4, 5-HT5A, 5-HT6, 5-HT7), reuptake (serotonin transporter), and degradation (monoamine oxidase A). A growing body of evidence from preclinical rodents models, and especially genetically modified mice and inbred mouse strains, has provided significant insight into how genetic variation in these molecules can affect the development and function of a key neural circuit between the dorsal raphe nucleus, medial prefrontal cortex and amygdala. By extension, such variation is hypothesized to have a major influence on individual differences in the stress response and risk for stress-related disease in humans. The current article provides an update on this rapidly evolving field of research. PMID:18439676

  17. [Tissue Doppler in the assessment of myocardial function in stress echocardiography].

    PubMed

    Citro, Rodolfo; Salustri, Alessandro; Trambaiolo, Paolo; Gregorio, Giovanni

    2002-02-01

    Recently, stress echocardiography has emerged as a valuable tool for the diagnosis and evaluation of coronary artery disease, but its interpretation still remains subjective, relying on image quality and reader's experience. These problems could be overcome by quantitative analysis of wall motion. Tissue Doppler provides quantitative information on regional myocardial systolic and diastolic velocities that can be displayed either in spectral mode or color coded, reflecting the peak velocity increment induced by exercise or dobutamine administration. Pulsed wave tissue Doppler allows to measure regional instantaneous myocardial velocities with high temporal resolution and has been shown valuable for detecting stress-induced changes of both myocardial systolic and diastolic function. This method may also identify myocardial viability by measuring increase in systolic peak velocity at low-dose of dobutamine in dysfunctional myocardial segments. Color coded tissue Doppler resolves mean velocities with higher spatial resolution, and post-processing analysis of digital acquired images has been shown feasible and reproducible. Myocardial velocity gradient is a more sensitive parameter compared to the simple measurement of the peak endocardial systolic velocity for evaluating myocardial ischemia during dobutamine echocardiography. From the raw data, it is also possible to measure strain and strain rate. These new parameters have the potential to differentiate between wall motion and contractility, with obvious implications when applied to stress echocardiography. In conclusion, tissue Doppler is able to quantify regional myocardial function. After a large scale validation, this technique will be incorporated with stress echocardiography in clinical practice.

  18. GABAergic regulation of the HPA and HPG axes and the impact of stress on reproductive function.

    PubMed

    Camille Melón, Laverne; Maguire, Jamie

    2016-06-01

    The hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes are regulated by GABAergic signaling at the level of corticotropin-releasing hormone (CRH) and gonadotropin-releasing hormone (GnRH) neurons, respectively. Under basal conditions, activity of CRH and GnRH neurons are controlled in part by both phasic and tonic GABAergic inhibition, mediated by synaptic and extrasynaptic GABAA receptors (GABAARs), respectively. For CRH neurons, this tonic GABAergic inhibition is mediated by extrasynaptic, δ subunit-containing GABAARs. Similarly, a THIP-sensitive tonic GABAergic current has been shown to regulate GnRH neurons, suggesting a role for δ subunit-containing GABAARs; however, this remains to be explicitly demonstrated. GABAARs incorporating the δ subunit confer neurosteroid sensitivity, suggesting a potential role for neurosteroid modulation in the regulation of the HPA and HPG axes. Thus, stress-derived neurosteroids may contribute to the impact of stress on reproductive function. Interestingly, excitatory actions of GABA have been demonstrated in both CRH neurons at the apex of control of the HPA axis and in GnRH neurons which mediate the HPG axis, adding to the complexity for the role of GABAergic signaling in the regulation of these systems. Here we review the effects that stress has on GnRH neurons and HPG axis function alongside evidence supporting GABAARs as a major interface between the stress and reproductive axes.

  19. GABAergic regulation of the HPA and HPG axes and the impact of stress on reproductive function.

    PubMed

    Camille Melón, Laverne; Maguire, Jamie

    2016-06-01

    The hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes are regulated by GABAergic signaling at the level of corticotropin-releasing hormone (CRH) and gonadotropin-releasing hormone (GnRH) neurons, respectively. Under basal conditions, activity of CRH and GnRH neurons are controlled in part by both phasic and tonic GABAergic inhibition, mediated by synaptic and extrasynaptic GABAA receptors (GABAARs), respectively. For CRH neurons, this tonic GABAergic inhibition is mediated by extrasynaptic, δ subunit-containing GABAARs. Similarly, a THIP-sensitive tonic GABAergic current has been shown to regulate GnRH neurons, suggesting a role for δ subunit-containing GABAARs; however, this remains to be explicitly demonstrated. GABAARs incorporating the δ subunit confer neurosteroid sensitivity, suggesting a potential role for neurosteroid modulation in the regulation of the HPA and HPG axes. Thus, stress-derived neurosteroids may contribute to the impact of stress on reproductive function. Interestingly, excitatory actions of GABA have been demonstrated in both CRH neurons at the apex of control of the HPA axis and in GnRH neurons which mediate the HPG axis, adding to the complexity for the role of GABAergic signaling in the regulation of these systems. Here we review the effects that stress has on GnRH neurons and HPG axis function alongside evidence supporting GABAARs as a major interface between the stress and reproductive axes. PMID:26690789

  20. Two Dictyostelium tyrosine kinase–like kinases function in parallel, stress-induced STAT activation pathways

    PubMed Central

    Araki, Tsuyoshi; Vu, Linh Hai; Sasaki, Norimitsu; Kawata, Takefumi; Eichinger, Ludwig; Williams, Jeffrey G.

    2014-01-01

    When Dictyostelium cells are hyperosmotically stressed, STATc is activated by tyrosine phosphorylation. Unusually, activation is regulated by serine phosphorylation and consequent inhibition of a tyrosine phosphatase: PTP3. The identity of the cognate tyrosine kinase is unknown, and we show that two tyrosine kinase–like (TKL) enzymes, Pyk2 and Pyk3, share this function; thus, for stress-induced STATc activation, single null mutants are only marginally impaired, but the double mutant is nonactivatable. When cells are stressed, Pyk2 and Pyk3 undergo increased autocatalytic tyrosine phosphorylation. The site(s) that are generated bind the SH2 domain of STATc, and then STATc becomes the target of further kinase action. The signaling pathways that activate Pyk2 and Pyk3 are only partially overlapping, and there may be a structural basis for this difference because Pyk3 contains both a TKL domain and a pseudokinase domain. The latter functions, like the JH2 domain of metazoan JAKs, as a negative regulator of the kinase domain. The fact that two differently regulated kinases catalyze the same phosphorylation event may facilitate specific targeting because under stress, Pyk3 and Pyk2 accumulate in different parts of the cell; Pyk3 moves from the cytosol to the cortex, whereas Pyk2 accumulates in cytosolic granules that colocalize with PTP3. PMID:25143406

  1. SIRT3 Functions in the Nucleus in the Control of Stress-Related Gene Expression

    PubMed Central

    Iwahara, Toshinori; Bonasio, Roberto; Narendra, Varun

    2012-01-01

    SIRT3 is a member of the Sir2 family of NAD+-dependent protein deacetylases that promotes longevity in many organisms. The processed short form of SIRT3 is a well-established mitochondrial protein whose deacetylase activity regulates various metabolic processes. However, the presence of full-length (FL) SIRT3 in the nucleus and its functional importance remain controversial. Our previous studies demonstrated that nuclear FL SIRT3 functions as a histone deacetylase and is transcriptionally repressive when artificially recruited to a reporter gene. Here, we report that nuclear FL SIRT3 is subjected to rapid degradation under conditions of cellular stress, including oxidative stress and UV irradiation, whereas the mitochondrial processed form is unaffected. FL SIRT3 degradation is mediated by the ubiquitin-proteasome pathway, at least partially through the ubiquitin protein ligase (E3) activity of SKP2. Finally, we show by chromatin immunoprecipitation that some target genes of nuclear SIRT3 are derepressed upon degradation of SIRT3 caused by stress stimuli. Thus, SIRT3 exhibits a previously unappreciated role in the nucleus, modulating the expression of some stress-related and nuclear-encoded mitochondrial genes. PMID:23045395

  2. Increased Oxidative Stress Impairs Adipose Tissue Function in Sphingomyelin Synthase 1 Null Mice

    PubMed Central

    Nishimura, Naotaka; Gotoh, Tomomi; Watanabe, Ken; Ikeda, Kazutaka; Garan, Yohei; Taguchi, Ryo; Node, Koichi; Okazaki, Toshiro; Oike, Yuichi

    2013-01-01

    Sphingomyelin synthase 1 (SMS1) catalyzes the conversion of ceramide to sphingomyelin. Here, we found that SMS1 null mice showed lipodystrophic phenotype. Mutant mice showed up-regulation of plasma triglyceride concentrations accompanied by reduction of white adipose tissue (WAT) as they aged. Lipoprotein lipase (LPL) activity was severely reduced in mutant mice. In vivo analysis indicated that fatty acid uptake in WAT but not in liver decreased in SMS1 null compared to wild-type mice. In vitro analysis using cultured cell revealed that SMS1 depletion reduced fatty acid uptake. Proteins extracted from WAT of mutant mice were severely modified by oxidative stress, and up-regulation of mRNAs related to apoptosis, redox adjustment, mitochondrial stress response and mitochondrial biogenesis was observed. ATP content of WAT was reduced in SMS1 null mice. Blue native gel analysis indicated that accumulation of mitochondrial respiratory chain complexes was reduced. These results suggest that WAT of SMS1 null mice is severely damaged by oxidative stress and barely functional. Indeed, mutant mice treated with the anti-oxidant N-acetyl cysteine (NAC) showed partial recovery of lipodystrophic phenotypes together with normalized plasma triglyceride concentrations. Altogether, our data suggest that SMS1 is crucial to control oxidative stress in order to maintain WAT function. PMID:23593476

  3. Global functions in global-local finite-element analysis of localized stresses in prismatic structures

    NASA Technical Reports Server (NTRS)

    Dong, Stanley B.

    1989-01-01

    An important consideration in the global local finite-element method (GLFEM) is the availability of global functions for the given problem. The role and mathematical requirements of these global functions in a GLFEM analysis of localized stress states in prismatic structures are discussed. A method is described for determining these global functions. Underlying this method are theorems due to Toupin and Knowles on strain energy decay rates, which are related to a quantitative expression of Saint-Venant's principle. It is mentioned that a mathematically complete set of global functions can be generated, so that any arbitrary interface condition between the finite element and global subregions can be represented. Convergence to the true behavior can be achieved with increasing global functions and finite-element degrees of freedom. Specific attention is devoted to mathematically two-dimensional and three-dimensional prismatic structures. Comments are offered on the GLFEM analysis of NASA flat panel with a discontinuous stiffener. Methods for determining global functions for other effects are also indicated, such as steady-state dynamics and bodies under initial stress.

  4. Avocado Oil Improves Mitochondrial Function and Decreases Oxidative Stress in Brain of Diabetic Rats.

    PubMed

    Ortiz-Avila, Omar; Esquivel-Martínez, Mauricio; Olmos-Orizaba, Berenice Eridani; Saavedra-Molina, Alfredo; Rodriguez-Orozco, Alain R; Cortés-Rojo, Christian

    2015-01-01

    Diabetic encephalopathy is a diabetic complication related to the metabolic alterations featuring diabetes. Diabetes is characterized by increased lipid peroxidation, altered glutathione redox status, exacerbated levels of ROS, and mitochondrial dysfunction. Although the pathophysiology of diabetic encephalopathy remains to be clarified, oxidative stress and mitochondrial dysfunction play a crucial role in the pathogenesis of chronic diabetic complications. Taking this into consideration, the aim of this work was to evaluate the effects of 90-day avocado oil intake in brain mitochondrial function and oxidative status in streptozotocin-induced diabetic rats (STZ rats). Avocado oil improves brain mitochondrial function in diabetic rats preventing impairment of mitochondrial respiration and mitochondrial membrane potential (ΔΨ m ), besides increasing complex III activity. Avocado oil also decreased ROS levels and lipid peroxidation and improved the GSH/GSSG ratio as well. These results demonstrate that avocado oil supplementation prevents brain mitochondrial dysfunction induced by diabetes in association with decreased oxidative stress. PMID:26180820

  5. Avocado Oil Improves Mitochondrial Function and Decreases Oxidative Stress in Brain of Diabetic Rats

    PubMed Central

    Ortiz-Avila, Omar; Esquivel-Martínez, Mauricio; Olmos-Orizaba, Berenice Eridani; Saavedra-Molina, Alfredo; Rodriguez-Orozco, Alain R.; Cortés-Rojo, Christian

    2015-01-01

    Diabetic encephalopathy is a diabetic complication related to the metabolic alterations featuring diabetes. Diabetes is characterized by increased lipid peroxidation, altered glutathione redox status, exacerbated levels of ROS, and mitochondrial dysfunction. Although the pathophysiology of diabetic encephalopathy remains to be clarified, oxidative stress and mitochondrial dysfunction play a crucial role in the pathogenesis of chronic diabetic complications. Taking this into consideration, the aim of this work was to evaluate the effects of 90-day avocado oil intake in brain mitochondrial function and oxidative status in streptozotocin-induced diabetic rats (STZ rats). Avocado oil improves brain mitochondrial function in diabetic rats preventing impairment of mitochondrial respiration and mitochondrial membrane potential (ΔΨm), besides increasing complex III activity. Avocado oil also decreased ROS levels and lipid peroxidation and improved the GSH/GSSG ratio as well. These results demonstrate that avocado oil supplementation prevents brain mitochondrial dysfunction induced by diabetes in association with decreased oxidative stress. PMID:26180820

  6. Dynamic droplets: the role of cytoplasmic inclusions in stress, function, and disease.

    PubMed

    Amen, Triana; Kaganovich, Daniel

    2015-02-01

    Neurodegenerative diseases and other proteinopathies constitute a class of several dozen illnesses etiologically linked to pathological protein misfolding and aggregation. Because of this strong association with disease pathology, cell death, and aging, accumulation of proteins in aggregates or aggregation-associated structures (inclusions) has come to be regarded by many as a deleterious process, to be avoided if possible. Recent work has led us to see inclusion structures and disordered aggregate-like protein mixtures (which we call dynamic droplets) in a new light: not necessarily as a result of a pathological breakdown of cellular order, but as an elaborate cellular architecture regulating function and stress response. In this review, we discuss what is currently known about the role of inclusion structures in cellular homeostasis, stress response, toxicity, and disease. We will focus on possible mechanisms of aggregate toxicity, in contrast to the homeostatic function of several inclusion structures.

  7. Avocado Oil Improves Mitochondrial Function and Decreases Oxidative Stress in Brain of Diabetic Rats.

    PubMed

    Ortiz-Avila, Omar; Esquivel-Martínez, Mauricio; Olmos-Orizaba, Berenice Eridani; Saavedra-Molina, Alfredo; Rodriguez-Orozco, Alain R; Cortés-Rojo, Christian

    2015-01-01

    Diabetic encephalopathy is a diabetic complication related to the metabolic alterations featuring diabetes. Diabetes is characterized by increased lipid peroxidation, altered glutathione redox status, exacerbated levels of ROS, and mitochondrial dysfunction. Although the pathophysiology of diabetic encephalopathy remains to be clarified, oxidative stress and mitochondrial dysfunction play a crucial role in the pathogenesis of chronic diabetic complications. Taking this into consideration, the aim of this work was to evaluate the effects of 90-day avocado oil intake in brain mitochondrial function and oxidative status in streptozotocin-induced diabetic rats (STZ rats). Avocado oil improves brain mitochondrial function in diabetic rats preventing impairment of mitochondrial respiration and mitochondrial membrane potential (ΔΨ m ), besides increasing complex III activity. Avocado oil also decreased ROS levels and lipid peroxidation and improved the GSH/GSSG ratio as well. These results demonstrate that avocado oil supplementation prevents brain mitochondrial dysfunction induced by diabetes in association with decreased oxidative stress.

  8. Children's predisaster functioning as a predictor of posttraumatic stress following Hurricane Andrew.

    PubMed

    La Greca, A M; Silverman, W K; Wasserstein, S B

    1998-12-01

    This study examined (a) children's predisaster behavioral and academic functioning as a predictor of posttraumatic stress (PTS) following Hurricane Andrew and (b) whether children who were exposed to the disaster would display a worsening of prior functioning. Fifteen months before the disaster, 92 4th through 6th graders provided self-reports of anxiety; peers and teachers rated behavior problems (anxiety, inattention, and conduct) and academic skills. Measures were repeated 3 months postdisaster; children also reported PTS symptoms and hurricane-related experiences (i.e., exposure). PTS symptoms were again assessed 7 months postdisaster. At 3 months postdisaster, children's exposure to the disaster, as well as predisaster ratings of anxiety, inattention, and academic skills, predicted PTS symptoms. By 7 months, only exposure, African American ethnicity, and predisaster anxiety predicted PTS. Prior anxiety levels also worsened as a result of exposure to the disaster. The findings have implications for identifying and treating children at risk for stress reactions following a catastrophic disaster.

  9. An approximate solution to the stress and deformation states of functionally graded rotating disks

    NASA Astrophysics Data System (ADS)

    Sondhi, Lakshman; Sanyal, Shubhashis; Saha, Kashi Nath; Bhowmick, Shubhankar

    2016-07-01

    The present work employs variational principle to investigate the stress and deformation states and estimate the limit angular speed of functionally graded high-speed rotating annular disks of constant thickness. Assuming a series approximation following Galerkin's principle, the solution of the governing equation is obtained. In the present study, elasticity modulus and density of the disk material are taken as power function of radius with the gradient parameter ranging between 0.0 and 1.0. Results obtained from numerical solutions are validated with benchmark results and are found to be in good agreement. The results are reported in dimensional form and presented graphically. The results provide a substantial insight in understanding the behavior of FGM rotating disks with constant thickness and different gradient parameter. Furthermore, the stress and deformation state of the disk at constant angular speed and limit angular speed is investigated to explain the existence of optimum gradient parameters.

  10. Glycolytic Enzymes Localize to Synapses under Energy Stress to Support Synaptic Function.

    PubMed

    Jang, SoRi; Nelson, Jessica C; Bend, Eric G; Rodríguez-Laureano, Lucelenie; Tueros, Felipe G; Cartagenova, Luis; Underwood, Katherine; Jorgensen, Erik M; Colón-Ramos, Daniel A

    2016-04-20

    Changes in neuronal activity create local and transient changes in energy demands at synapses. Here we discover a metabolic compartment that forms in vivo near synapses to meet local energy demands and support synaptic function in Caenorhabditis elegans neurons. Under conditions of energy stress, glycolytic enzymes redistribute from a diffuse localization in the cytoplasm to a punctate localization adjacent to synapses. Glycolytic enzymes colocalize, suggesting the ad hoc formation of a glycolysis compartment, or a "glycolytic metabolon," that can maintain local levels of ATP. Local formation of the glycolytic metabolon is dependent on presynaptic scaffolding proteins, and disruption of the glycolytic metabolon blocks the synaptic vesicle cycle, impairs synaptic recovery, and affects locomotion. Our studies indicate that under energy stress conditions, energy demands in C. elegans synapses are met locally through the assembly of a glycolytic metabolon to sustain synaptic function and behavior. VIDEO ABSTRACT.

  11. [Stress-induced changes in functional activity of the neuro-endocrine system: modulatory action of derinat].

    PubMed

    Fomicheva, E E; Filatenkova, T A; Shanin, S N; Rybakina, E G

    2009-03-01

    Changes in functional activity of HPA and HPG axes under stress influences of different intensity, and possible ways for their correction by native DNA preparation: derinat, possessing immune modulator effects, were studied. It was shown that the vector of changes in hormone's reactions of both axes did not depend on the intensity of stress influences: different models of stress increased corticosterone level and decreased testosterone level in rats' blood. Intraperitoneal injection of 10 and 50 mg/kg BW doses of Derinat to rats enhanced HPA and HPG axes activity, reversed stress-induced decrease of testosterone concentration in blood, that may indicate a stress-protective effect of derinat. Injection of derinat caused normalizing of stress-induced changes in immunomodulatory cytokines production within Lymphocyte Activating Factors, which regulate not only the immune system functions but also the functions of HPA and HPG axes.

  12. Hibernation, stress, intestinal functions, and catecholoamine turnover rate in hamsters and gerbils

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.

    1973-01-01

    Bioenergetic studies on hamsters during depressed metabolic states are reported. External support of blood glucose extended the survival times of hibernating animals. Radioresistance increased in hibernating as well as in hypothermic hamsters. Marked changes in hamster catecholamine turnover rates were observed during acclimatization to high temperature stress. High radioresistance levels of the gerbil gastrointestinal system were attributed in part to the ability of the gut to maintain functional integrity.

  13. Analysis of stress singularities at singular points of elastic solids made of functionally graded materials

    NASA Astrophysics Data System (ADS)

    Matveenko, V. P.; Fedorov, A. Yu.; Shardakov, I. N.

    2016-01-01

    The results of analytical and numerical investigations on estimating the character of the singularity of stresses in a vicinity of different variants of special points of the 2D elastic solids made of functionally graded materials (FGMs) are presented. The variant of construction by analytical methods in the polar system of coordinates is considered for eigensolutions in the flat wedges made of the FGM, the elastic properties of which are represented as power series in terms of the radial coordinate.

  14. Diosmin pretreatment improves cardiac function and suppresses oxidative stress in rat heart after ischemia/reperfusion.

    PubMed

    Senthamizhselvan, Oomaidurai; Manivannan, Jeganathan; Silambarasan, Thangarasu; Raja, Boobalan

    2014-08-01

    Reperfusion of ischemic tissue leads to the generation of oxygen derived free radicals which plays an important role in cellular damage. Objective of the current study is to evaluate the cardio-protective and antioxidant effect of diosmin on ischemia-reperfusion related cardiac dysfunction, oxidative stress and apoptosis. Diosmin (50 and 100 mg/kg body weight (bw)) was given every day to the rats orally throughout the experimental period. Ischemia/reperfusion protocol was carried out ex vivo using langendorff perfusion method and the cardiac functional recovery was assessed in terms of percentage rate pressure product. Coronary effluents of LDH and CK-MB activities, antioxidant enzyme activities, lipid peroxidation products, activity of TCA cycle enzymes were evaluated. Moreover, in vitro superoxide anion and hydroxyl radical scavenging potential of diosmin was also quantified. Finally, quantitative real-time PCR was used for assessing Bcl-2 mRNA expression in heart. Cardiac functional recovery was impaired after reperfusion compared with continuously perfused heart. It was significantly prevented by diosmin treatment. Impaired antioxidant enzyme activities and elevated lipid peroxidation products level were also significantly suppressed. The activity of TCA cycle enzymes was protected against reperfusion stress. Down regulated Bcl-2 was also significantly increased. This study concluded that diosmin pretreatment prevents all the impaired patterns including cardiac function, oxidative stress and apoptosis associated with reperfusion in control heart by its antioxidant role.

  15. Alternative splicing of Drosophila Nmnat functions as a switch to enhance neuroprotection under stress

    PubMed Central

    Ruan, Kai; Zhu, Yi; Li, Chong; Brazill, Jennifer M.; Zhai, R. Grace

    2015-01-01

    Nicotinamide mononucleotide adenylyltransferase (NMNAT) is a conserved enzyme in the NAD synthetic pathway. It has also been identified as an effective and versatile neuroprotective factor. However, it remains unclear how healthy neurons regulate the dual functions of NMNAT and achieve self-protection under stress. Here we show that Drosophila Nmnat (DmNmnat) is alternatively spliced into two mRNA variants, RA and RB, which translate to protein isoforms with divergent neuroprotective capacities against spinocerebellar ataxia 1-induced neurodegeneration. Isoform PA/PC translated from RA is nuclear-localized with minimal neuroprotective ability, and isoform PB/PD translated from RB is cytoplasmic and has robust neuroprotective capacity. Under stress, RB is preferably spliced in neurons to produce the neuroprotective PB/PD isoforms. Our results indicate that alternative splicing functions as a switch that regulates the expression of functionally distinct DmNmnat variants. Neurons respond to stress by driving the splicing switch to produce the neuroprotective variant and therefore achieve self-protection. PMID:26616331

  16. Alternative splicing of Drosophila Nmnat functions as a switch to enhance neuroprotection under stress.

    PubMed

    Ruan, Kai; Zhu, Yi; Li, Chong; Brazill, Jennifer M; Zhai, R Grace

    2015-11-30

    Nicotinamide mononucleotide adenylyltransferase (NMNAT) is a conserved enzyme in the NAD synthetic pathway. It has also been identified as an effective and versatile neuroprotective factor. However, it remains unclear how healthy neurons regulate the dual functions of NMNAT and achieve self-protection under stress. Here we show that Drosophila Nmnat (DmNmnat) is alternatively spliced into two mRNA variants, RA and RB, which translate to protein isoforms with divergent neuroprotective capacities against spinocerebellar ataxia 1-induced neurodegeneration. Isoform PA/PC translated from RA is nuclear-localized with minimal neuroprotective ability, and isoform PB/PD translated from RB is cytoplasmic and has robust neuroprotective capacity. Under stress, RB is preferably spliced in neurons to produce the neuroprotective PB/PD isoforms. Our results indicate that alternative splicing functions as a switch that regulates the expression of functionally distinct DmNmnat variants. Neurons respond to stress by driving the splicing switch to produce the neuroprotective variant and therefore achieve self-protection.

  17. Diverse functional interactions between nitric oxide and abscisic acid in plant development and responses to stress.

    PubMed

    León, José; Castillo, Mari Cruz; Coego, Alberto; Lozano-Juste, Jorge; Mir, Ricardo

    2014-03-01

    The extensive support for abscisic acid (ABA) involvement in the complex regulatory networks controlling stress responses and development in plants contrasts with the relatively recent role assigned to nitric oxide (NO). Because treatment with exogenous ABA leads to enhanced production of NO, it has been widely considered that NO participates downstream of ABA in controlling processes such as stomata movement, seed dormancy, and germination. However, data on leaf senescence and responses to stress suggest that the functional interaction between ABA and NO is more complex than previously thought, including not only cooperation but also antagonism. The functional relationship is probably determined by several factors including the time- and place-dependent pattern of accumulation of both molecules, the threshold levels, and the regulatory factors important for perception. These factors will determine the actions exerted by each regulator. Here, several examples of well-documented functional interactions between NO and ABA are analysed in light of the most recent reported data on seed dormancy and germination, stomata movements, leaf senescence, and responses to abiotic and biotic stresses.

  18. Acute and chronic stress-induced disturbances of microglial plasticity, phenotype and function.

    PubMed

    Walker, Frederick Rohan; Nilsson, Michael; Jones, Kimberley

    2013-10-01

    Traditionally, microglia have been considered to act as macrophages of the central nervous system. While this concept still remains true it is also becoming increasingly apparent that microglia are involved in a host of nonimmunological activities, such as monitoring synaptic function and maintaining synaptic integrity. It has also become apparent that microglia are exquisitely sensitive to perturbation by environmental challenges. The aim of the current review is to critically examine the now substantial literature that has developed around the ability of acute, sub-chronic and chronic stressors to alter microglial structure and function. The vast majority of studies have demonstrated that stress promotes significant structural remodelling of microglia, and can enhance the release of pro-inflammatory cytokines from microglia. Mechanistically, many of these effects appear to be driven by traditional stress-linked signalling molecules, namely corticosterone and norepinephrine. The specific effects of these signalling molecules are, however, complex as they can exert both inhibitory and suppressive effects on microglia depending upon the duration and intensity of exposure. Importantly, research has now shown that these stress-induced microglial alterations, rather than being epiphenomena, have broader behavioural implications, with the available evidence implicating microglia in directly regulating certain aspects of cognitive function and emotional regulation. PMID:24020974

  19. Functional annotation of the transcriptome of Sorghum bicolor in response to osmotic stress and abscisic acid

    PubMed Central

    2011-01-01

    Background Higher plants exhibit remarkable phenotypic plasticity allowing them to adapt to an extensive range of environmental conditions. Sorghum is a cereal crop that exhibits exceptional tolerance to adverse conditions, in particular, water-limiting environments. This study utilized next generation sequencing (NGS) technology to examine the transcriptome of sorghum plants challenged with osmotic stress and exogenous abscisic acid (ABA) in order to elucidate genes and gene networks that contribute to sorghum's tolerance to water-limiting environments with a long-term aim of developing strategies to improve plant productivity under drought. Results RNA-Seq results revealed transcriptional activity of 28,335 unique genes from sorghum root and shoot tissues subjected to polyethylene glycol (PEG)-induced osmotic stress or exogenous ABA. Differential gene expression analyses in response to osmotic stress and ABA revealed a strong interplay among various metabolic pathways including abscisic acid and 13-lipoxygenase, salicylic acid, jasmonic acid, and plant defense pathways. Transcription factor analysis indicated that groups of genes may be co-regulated by similar regulatory sequences to which the expressed transcription factors bind. We successfully exploited the data presented here in conjunction with published transcriptome analyses for rice, maize, and Arabidopsis to discover more than 50 differentially expressed, drought-responsive gene orthologs for which no function had been previously ascribed. Conclusions The present study provides an initial assemblage of sorghum genes and gene networks regulated by osmotic stress and hormonal treatment. We are providing an RNA-Seq data set and an initial collection of transcription factors, which offer a preliminary look into the cascade of global gene expression patterns that arise in a drought tolerant crop subjected to abiotic stress. These resources will allow scientists to query gene expression and functional

  20. Maternal stress, nutrition and physical activity: Impact on immune function, CNS development and psychopathology.

    PubMed

    Marques, Andrea Horvath; Bjørke-Monsen, Anne-Lise; Teixeira, Antônio L; Silverman, Marni N

    2015-08-18

    Evidence suggests that maternal and fetal immune dysfunction may impact fetal brain development and could play a role in neurodevelopmental disorders, although the definitive pathophysiological mechanisms are still not completely understood. Stress, malnutrition and physical inactivity are three maternal behavioral lifestyle factors that can influence immune and central nervous system (CNS) functions in both the mother and fetus, and may therefore, increase risk for neurodevelopmental/psychiatric disorders. First, we will briefly review some aspects of maternal-fetal immune system interactions and development of immune tolerance. Second, we will discuss the bidirectional communication between the immune system and CNS and the pathways by which immune dysfunction could contribute to neurodevelopmental disorders. Third, we will discuss the effects of prenatal stress and malnutrition (over and undernutrition) on perinatal programming of the CNS and immune system, and how this might influence neurodevelopment. Finally, we will discuss the beneficial impact of physical fitness during pregnancy on the maternal-fetal unit and infant and how regular physical activity and exercise can be an effective buffer against stress- and inflammatory-related disorders. Although regular physical activity has been shown to promote neuroplasticity and an anti-inflammatory state in the adult, there is a paucity of studies evaluating its impact on CNS and immune function during pregnancy. Implementing stress reduction, proper nutrition and ample physical activity during pregnancy and the childbearing period may be an efficient strategy to counteract the impact of maternal stress and malnutrition/obesity on the developing fetus. Such behavioral interventions could have an impact on early development of the CNS and immune system and contribute to the prevention of neurodevelopmental and psychiatric disorders. Further research is needed to elucidate this relationship and the underlying

  1. Chronic maternal stress affects growth, behaviour and hypothalamo-pituitary-adrenal function in juvenile offspring.

    PubMed

    Emack, Jeff; Kostaki, Alice; Walker, Claire-Dominique; Matthews, Stephen G

    2008-09-01

    Maternal stress during pregnancy, particularly that combined with low socioeconomic status (SES), has been linked to an increased risk for impaired behavioural and emotional development and affective disorders in children. In animal models, acute periods of prenatal stress have profound effects on hypothalamo-pituitary-adrenal (HPA) function and behaviour. However, few studies have determined the impact of chronic exposure to stress in animal models. The objective of this study was to determine the effects of chronic maternal stress (CMS) during the 2nd half of pregnancy and nursing on growth, locomotor behaviour and HPA axis function in juvenile guinea pig offspring. Pregnant guinea pigs were exposed to a random combination of variable stressors every other day over the 2nd half of gestation and from postnatal day (pnd) 1 until weaning (pnd25). CMS mothers displayed increased basal salivary cortisol levels in the later stages of pregnancy compared to control mothers (p<0.05). The male offspring of CMS mothers had a lower bodyweight, which was maintained to weaning (p<0.01). In open-field testing, CMS male offspring showed a decrease in activity compared to controls (p<0.05). There was no effect of CMS on bodyweight or activity in female offspring. In contrast, both male and female offspring born to CMS mothers displayed increased (p<0.05) basal salivary cortisol at pnd25, but a blunted adrenocortical response to exposure to the novel open-field enclosure. In conclusion, CMS leads to modification of growth trajectory, locomotor activity and adrenocortical responses to stress in juvenile offspring. Further, males appear considerably more vulnerable to these effects than females. PMID:18674758

  2. The Influence of Work-Related Chronic Stress on the Regulation of Emotion and on Functional Connectivity in the Brain

    PubMed Central

    Golkar, Armita; Johansson, Emilia; Kasahara, Maki; Osika, Walter; Perski, Aleksander; Savic, Ivanka

    2014-01-01

    Despite mounting reports about the negative effects of chronic occupational stress on cognitive and emotional functions, the underlying mechanisms are unknown. Recent findings from structural MRI raise the question whether this condition could be associated with a functional uncoupling of the limbic networks and an impaired modulation of emotional stress. To address this, 40 subjects suffering from burnout symptoms attributed to chronic occupational stress and 70 controls were investigated using resting state functional MRI. The participants' ability to up- regulate, down-regulate, and maintain emotion was evaluated by recording their acoustic startle response while viewing neutral and negatively loaded images. Functional connectivity was calculated from amygdala seed regions, using explorative linear correlation analysis. Stressed subjects were less capable of down-regulating negative emotion, but had normal acoustic startle responses when asked to up-regulate or maintain emotion and when no regulation was required. The functional connectivity between the amygdala and the anterior cingulate cortex correlated with the ability to down-regulate negative emotion. This connectivity was significantly weaker in the burnout group, as was the amygdala connectivity with the dorsolateral prefrontal cortex and the motor cortex, whereas connectivity from the amygdala to the cerebellum and the insular cortex were stronger. In subjects suffering from chronic occupational stress, the functional couplings within the emotion- and stress-processing limbic networks seem to be altered, and associated with a reduced ability to down-regulate the response to emotional stress, providing a biological substrate for a further facilitation of the stress condition. PMID:25184294

  3. [Effects of exogenous spermidine on mitochondrial function of tomato seedling roots under salinity-alkalinity stress].

    PubMed

    Pan, Xiong-bo; Xiang, Li-xia; Hu, Xiao-hui; Ren, Wen-qi; Zhang, Li; Ni, Xin-xin

    2016-02-01

    Two cultivars of tomato (Solanum lycopersicum, cvs. 'Jinpengchaoguan' and 'Zhongza No. 9', with the former being more tolerant to saline-alkaline stress) seedlings grown hydroponically were subjected to salinity-alkalinity stress condition (NaCl: Na2SO4:NaHCO3:Na2CO3 = 1:9:9:1) without or with foliar application of 0.25 mmol . L-1 spermidine (Spd), and the root morphology and physiological characteristics of mitochondrial membrane were analyzed 8 days after treatment, to explore the protective effects of exogenous Spd on mitochondrial function in tomato roots under salinity-alkalinity stress. The results showed that the salinity-alkalinity stress increased the concentrations of both mitochondrial H2O2 and MDA as well as the mitochondrial membrane permeability in the roots of the two cultivars, while it decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity, which impaired the mitochondria and therefore inhibited the root growth; and these effects were more obvious in 'Zhongza No. 9' than in 'Jinpengechaoguan'. Under the salinity-alkalinity stress, foliar application Spd could effectively decrease the concentrations of mitochondrial H2O2 and MDA and mitochondrial membrane permeability, while increased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity. These results suggested that exogenous Spd could effectively mitigate the damage on mitochondria induced by salinity-alkalinity stress, and the alleviation effect was more obvious in 'Zhongza No. 9' than in 'Jinpengchaoguan'. PMID:27396122

  4. Universal Stress Protein Exhibits a Redox-Dependent Chaperone Function in Arabidopsis and Enhances Plant Tolerance to Heat Shock and Oxidative Stress.

    PubMed

    Jung, Young Jun; Melencion, Sarah Mae Boyles; Lee, Eun Seon; Park, Joung Hun; Alinapon, Cresilda Vergara; Oh, Hun Taek; Yun, Dae-Jin; Chi, Yong Hun; Lee, Sang Yeol

    2015-01-01

    Although a wide range of physiological information on Universal Stress Proteins (USPs) is available from many organisms, their biochemical, and molecular functions remain unidentified. The biochemical function of AtUSP (At3g53990) from Arabidopsis thaliana was therefore investigated. Plants over-expressing AtUSP showed a strong resistance to heat shock and oxidative stress, compared with wild-type and Atusp knock-out plants, confirming the crucial role of AtUSP in stress tolerance. AtUSP was present in a variety of structures including monomers, dimers, trimers, and oligomeric complexes, and switched in response to external stresses from low molecular weight (LMW) species to high molecular weight (HMW) complexes. AtUSP exhibited a strong chaperone function under stress conditions in particular, and this activity was significantly increased by heat treatment. Chaperone activity of AtUSP was critically regulated by the redox status of cells and accompanied by structural changes to the protein. Over-expression of AtUSP conferred a strong tolerance to heat shock and oxidative stress upon Arabidopsis, primarily via its chaperone function. PMID:26734042

  5. Cognitive adaptations to stressful environments: When childhood adversity enhances adult executive function.

    PubMed

    Mittal, Chiraag; Griskevicius, Vladas; Simpson, Jeffry A; Sung, Sooyeon; Young, Ethan S

    2015-10-01

    Can growing up in a stressful childhood environment enhance certain cognitive functions? Drawing participants from higher-income and lower-income backgrounds, we tested how adults who grew up in harsh or unpredictable environments fared on 2 types of executive function tasks: inhibition and shifting. People who experienced unpredictable childhoods performed worse at inhibition (overriding dominant responses), but performed better at shifting (efficiently switching between different tasks). This finding is consistent with the notion that shifting, but not inhibition, is especially useful in unpredictable environments. Importantly, differences in executive function between people who experienced unpredictable versus predictable childhoods emerged only when they were tested in uncertain contexts. This catalyst suggests that some individual differences related to early life experience are manifested under conditions of uncertainty in adulthood. Viewed as a whole, these findings indicate that adverse childhood environments do not universally impair mental functioning, but can actually enhance specific types of cognitive performance in the face of uncertainty. PMID:26414842

  6. Functions of FUS/TLS From DNA Repair to Stress Response: Implications for ALS

    PubMed Central

    Sama, Reddy Ranjith Kumar; Ward, Catherine L.

    2014-01-01

    Fused in sarcoma/translocated in liposarcoma (FUS/TLS or FUS) is a multifunctional DNA-/RNA-binding protein that is involved in a variety of cellular functions including transcription, protein translation, RNA splicing, and transport. FUS was initially identified as a fusion oncoprotein, and thus, the early literature focused on the role of FUS in cancer. With the recent discoveries revealing the role of FUS in neurodegenerative diseases, namely amyotrophic lateral sclerosis and frontotemporal lobar degeneration, there has been a renewed interest in elucidating the normal functions of FUS. It is not clear which, if any, endogenous functions of FUS are involved in disease pathogenesis. Here, we review what is currently known regarding the normal functions of FUS with an emphasis on DNA damage repair, RNA processing, and cellular stress response. Further, we discuss how ALS-causing mutations can potentially alter the role of FUS in these pathways, thereby contributing to disease pathogenesis. PMID:25289647

  7. Effects of post-traumatic stress disorder on occipital lobe function and structure.

    PubMed

    Chao, Linda L; Lenoci, Maryann; Neylan, Thomas C

    2012-05-01

    Although there is evidence for strong connectivity between the amygdala and the visual cortex and some evidence for reduced occipital lobe gray matter volume in patients with post-traumatic stress disorder (PTSD), few studies have directly examined the effects of PTSD on occipital function. The current study used functional and structural MRI to examine occipital cortex function and structure in male combat veterans with and without PTSD. Left occipital gray matter volume was reduced in PTSD patients relative to the controls and correlated negatively with the severity of PTSD symptoms. Functional activity in the lateral occipital complex to aversive and nonaversive pictures presented in novel and repeated presentations was not altered by PTSD. These findings suggest that PTSD adversely affects occipital lobe volume but not the reactivity of the lateral occipital complex to generally aversive, trauma nonspecific stimuli.

  8. Occupational Health Hazards among Sewage Workers: Oxidative Stress and Deranged Lung Functions

    PubMed Central

    Agrawal, Dhirendra Kumar; Aslam, Mohammad; Islam, Najmul; Ahmad, Zuber

    2014-01-01

    Background: Sewage workers, because of their occupation, are exposed to different types of dusts, bio-aerosols, fumes and gases like methane, hydrogen sulfide, sulphur dioxide, etc, which contribute towards oxidative stress and detrimental effects on various body functions, especially lung functions. Aims and Objectives: This study was carried out on sewage workers (who had been working for more than five years). We wanted to study the role of oxidative stress in development of impaired lung functions among sewage workers. Materials and Methods: This cross sectional study was done in a tertiary care hospital (J.N. Medical College) in Aligarh, U.P. Study was done from March 2008 to December 2009. The study group comprised of 62 sewage workers who had been working for more than five years (32 non-smokers and 30 smokers) and 60 control subjects (30 smokers and 30 non-smokers). The pulmonary functions of these workers were assessed by using a MIR (Medical International Lab) Spiro Lab II Spirometer, with subjects in sitting position. Valid written consents were obtained from all the subjects. Malondialdehyde (MDA) is produced as a result of the action of reactive oxygen species (ROS) on the lipids present in the membranes of the cells, especially, contracting muscle cells. Serum MDA levels were assessed as an indirect measure of oxidative stress in these sewage workers and they were compared with serum MDA levels of control subjects. Appropriate statistical tests were applied for analysis of the data which was generated. Observation and Results: There were statistically significant decreases in Peak Expiratory Flow Rate (PEFR), Forced Expiratory Volume in first second (FEV1) and FEV1/FVC percent ratio (<80%) and Forced Expiratory Flow at 25%-75% of volume as percentage of Vital Capacity (FEF 25%-75%). Also, we found statistically significant increased levels of serum MDA in these sewage workers as compared to those in control subjects (with a p-value of <0.05 with a

  9. Early Life Stress and Physical and Psychosocial Functioning in Late Adulthood

    PubMed Central

    Alastalo, Hanna; von Bonsdorff, Mikaela B.; Räikkönen, Katri; Pesonen, Anu-Katriina; Osmond, Clive; Barker, David J. P.; Heinonen, Kati; Kajantie, Eero; Eriksson, Johan G.

    2013-01-01

    Background Severe stress experienced in early life may have long-term effects on adult physiological and psychological health and well-being. We studied physical and psychosocial functioning in late adulthood in subjects separated temporarily from their parents in childhood during World War II. Methods The 1803 participants belong to the Helsinki Birth Cohort Study, born 1934–44. Of them, 267 (14.8%) had been evacuated abroad in childhood during WWII and the remaining subjects served as controls. Physical and psychosocial functioning was assessed with the Short Form 36 scale (SF-36) between 2001 and 2004. A test for trends was based on linear regression. All analyses were adjusted for age at clinical examination, social class in childhood and adulthood, smoking, alcohol intake, physical activity, body mass index, cardiovascular disease and diabetes. Results Physical functioning in late adulthood was lower among the separated men compared to non-separated men (b = −0.40, 95% confidence interval [95% CI]: −0.71 to −0.08). Those men separated in school age (>7 years) and who were separated for a duration over 2 years had the highest risk for lower physical functioning (b = −0.89, 95% CI: −1.58 to −0.20) and (b = −0.65, 95% CI: −1.25 to −0.05), respectively). Men separated for a duration over 2 years also had lower psychosocial functioning (b = −0.70, 95% CI: −1.35 to −0.06). These differences in physical and psychosocial functioning were not observed among women. Conclusion Early life stress may increase the risk for impaired physical functioning in late adulthood among men. Timing and duration of the separation influenced the physical and psychosocial functioning in late adulthood. PMID:23861956

  10. Mortalin and DJ-1 coordinately regulate hematopoietic stem cell function through the control of oxidative stress.

    PubMed

    Tai-Nagara, Ikue; Matsuoka, Sahoko; Ariga, Hiroyoshi; Suda, Toshio

    2014-01-01

    Hematopoietic stem cells (HSCs) maintain stemness through various mechanisms that protect against stressful conditions. Heat shock proteins (HSPs) preserve cell homeostasis during stress responses through protein quality control, suggesting that HSPs may safeguard HSCs against numerous traumas. Here, we show that mortalin, a mitochondrial HSP, plays an essential role in maintaining HSC properties by regulating oxidative stress. Mortalin is primarily localized in hematopoietic stem and progenitor cell (HSPC) compartments. In this study, the inhibition of mortalin function caused abnormal reactive oxygen species (ROS) elevation in HSCs and reduced HSC numbers. Knockdown (KD) of mortalin in HSPCs impaired their ability to repopulate and form colonies. Moreover, mortalin-KD HSCs could not maintain quiescence and showed severe downregulation of cyclin-dependent kinase inhibitor- and antioxidant-related genes. Conversely, HSCs that overexpressed mortalin maintained a high reconstitution capacity and low ROS levels. Furthermore, DJ-1, one of the genes responsible for Parkinson's disease, directly bound to mortalin and acted as a negative ROS regulator. Using DJ-1-deficient mice, we demonstrated that mortalin and DJ-1 coordinately maintain normal ROS levels and HSC numbers. Collectively, these results indicate that the mortalin/DJ-1 complex guards against mitochondrial oxidative stress and is indispensable for the maintenance of HSCs. PMID:24243970

  11. Advances in functional genomics for investigating salinity stress tolerance mechanisms in cereals.

    PubMed

    Shelden, Megan C; Roessner, Ute

    2013-01-01

    Abiotic stresses such as low water availability and high salinity are major causes of cereal crop yield losses and significantly impact on sustainability. Wheat and barley are two of the most important cereal crops (after maize and rice) and are grown in increasingly hostile environments with soil salinity and drought both expected to increase this century, reducing the availability of arable land. Barley and wheat are classified as glycophytes (salt-sensitive), yet they are more salt-tolerant than other cereal crops such as rice and so are good models for studying salt tolerance in cereals. The exploitation of genetic variation of phenotypic traits through plant breeding could significantly improve growth of cereals in salinity-affected regions, thus leading to improved crop yields. Genetic variation in phenotypic traits for abiotic stress tolerance have been identified in land races and wild germplasm but the molecular basis of these differences is often difficult to determine due to the complex genetic nature of these species. High-throughput functional genomics technologies, such as transcriptomics, metabolomics, proteomics, and ionomics are powerful tools for investigating the molecular responses of plants to abiotic stress. The advancement of these technologies has allowed for the identification and quantification of transcript/metabolites in specific cell types and/or tissues. Using these new technologies on plants will provide a powerful tool to uncovering genetic traits in more complex species such as wheat and barley and provide novel insights into the molecular mechanisms of salinity stress tolerance. PMID:23717314

  12. Function of MYB domain transcription factors in abiotic stress and epigenetic control of stress response in plant genome

    PubMed Central

    Roy, Sujit

    2016-01-01

    ABSTRACT Plants have developed highly efficient and remarkable mechanisms to survive under frequent and extreme environmental stress conditions. Exposure of plants to various stress factors is associated with coordinated changes in gene expression at the transcriptional level and hence transcription factors, such as those belonging to the MYB family play a central role in triggering the right responses. MYB transcription factors have been extensively studied in regard of their involvement in the regulation of a number of such stress responses in plants. Genetic and molecular biological studies, primarily in Arabidopsis, have also begun to unravel the role of MYB transcription factors in the epigenetic regulation of stress responses in plants. This review focuses on the role of MYB transcription factors in the regulation of various stress responses in general, highlighting on recent advances in our understanding of the involvement of this class of transcription factors in epigenetic regulation of stress response in plant genome. PMID:26636625

  13. Disrupted resting-state insular subregions functional connectivity in post-traumatic stress disorder.

    PubMed

    Zhang, Youxue; Xie, Bing; Chen, Heng; Li, Meiling; Guo, Xiaonan; Chen, Huafu

    2016-07-01

    Post-traumatic stress disorder (PTSD) is suggested to be a structural and functional abnormality in the insula. The insula, which consists of distinct subregions with various patterns of connectivity, displays complex and diverse functions. However, whether these insular subregions have different patterns of connectivity in PTSD remains unclear. Investigating the abnormal functional connectivity of the insular subregions is crucial to reveal its potential effect on diseases specifically PTSD. This study uses a seed-based method to investigate the altered resting-state functional connectivity of insular subregions in PTSD. We found that patients with PTSD showed reduced functional connectivity compared with healthy controls (HCs) between the left ventral anterior insula and the anterior cingulate cortex. The patients with PTSD also exhibited decreased functional connectivity between the right posterior insula and left inferior parietal lobe, and the postcentral gyrus relative to HCs. These results suggest the involvement of altered functional connectivity of insular subregions in the abnormal regulation of emotion and processing of somatosensory information in patients with PTSD. Such impairments in functional connectivity patterns of the insular subregions may advance our understanding of the pathophysiological basis underlying PTSD. PMID:27399097

  14. ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function

    SciTech Connect

    Pi Jingbo; Zhang Qiang; Fu Jingqi; Woods, Courtney G.; Hou Yongyong; Corkey, Barbara E.; Collins, Sheila; Andersen, Melvin E.

    2010-04-01

    This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H{sub 2}O{sub 2}, act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function.

  15. Effects of mechanical stresses on sperm function and fertilization rate in mice.

    PubMed

    Shi, Xiao; Wang, Ting; Qiu, Zhuo Lin; Li, Ke; Li, Liu; Chan, Carol Pui Shan; Chan, Si Mei; Li, Tian-Chiu; Quan, Song

    2016-01-01

    In this study, we investigated whether any of the observed changes in mouse sperm function tests secondary to mechanical stresses (centrifugation and pipetting) correlate with sperm fertilization ability. Chinese Kunming mice were used as sperm and oocyte donors. Sperm samples were allocated evenly into centrifugation, pipette, and control groups. Sperm plasma membrane integrity (PMI), mitochondrial membrane permeability (MMP), baseline and stimulated intracellular ROS, and sperm fertilization ability were measured by hypo-osmotic swelling, flow cytometry, and fertilization tests. Parallel studies were conducted and all tests were repeated six times. Our results showed that after centrifugation, the progressive motility, average path velocity, and overall sperm motility and PMI decreased significantly (p < 0.05). In addition, the MMP level decreased significantly in viable sperm when the centrifugation condition reached 1,400 g × 15 minutes (p < 0.05). When pipetting was performed two or more times, progressive motility, average path velocity, and overall sperm motility decreased significantly (p < 0.05); when it was performed four or more times, sperm membrane integrity and intracellular basal ROS level of viable sperm was also significantly decreased (p < 0.05). In conclusion, various mechanical stresses seem to affect sperm function, however this does not appear to alter fertilization rate. Laboratory handling steps should be minimized to avoid unnecessary mechanical stresses being applied to sperm samples. PMID:26889695

  16. Pea lectin receptor-like kinase functions in salinity adaptation without yield penalty, by alleviating osmotic and ionic stresses and upregulating stress-responsive genes.

    PubMed

    Vaid, Neha; Pandey, Prashant; Srivastava, Vineet Kumar; Tuteja, Narendra

    2015-05-01

    Lectin receptor-like kinases (LecRLKs) are members of RLK family composed of lectin-like extracellular recognition domain, transmembrane domain and cytoplasmic kinase domain. LecRLKs are plasma membrane proteins believed to be involved in signal transduction. However, most of the members of the protein family even in plants have not been functionally well characterized. Herein, we show that Pisum sativum LecRLK (PsLecRLK) localized in plasma membrane systems and/or other regions of the cell and its transcript upregulated under salinity stress. Overexpression of PsLecRLK in transgenic tobacco plants confers salinity stress tolerance by alleviating both the ionic as well the osmotic component of salinity stress. The transgenic plants show better tissue compartmentalization of Na(+) and higher ROS scavenging activity which probably results in lower membrane damage, improved growth and yield maintenance even under salinity stress. Also, expression of several genes involved in cellular homeostasis is perturbed by PsLecRLK overexpression. Alleviation of osmotic and ionic components of salinity stress along with reduced oxidative damage and upregulation of stress-responsive genes in transgenic plants under salinity stress conditions could be possible mechanism facilitating enhanced stress tolerance. This study presents PsLecRLK as a promising candidate for crop improvement and also opens up new avenue to investigate its signalling pathway.

  17. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    PubMed Central

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-01-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis – based on cellular components and biological process GO terms – was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in “Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation” [1]. PMID:27104213

  18. Acute exercise improves endothelial function despite increasing vascular resistance during stress in smokers and nonsmokers.

    PubMed

    Rooks, Cherie R; McCully, Kevin K; Dishman, Rod K

    2011-09-01

    The present study examined the effect of acute exercise on flow mediated dilation (FMD) and reactivity to neurovascular challenges among female smokers and nonsmokers. FMD was determined by arterial diameter, velocity, and blood flow measured by Doppler ultrasonography after forearm occlusion. Those measures and blood pressure and heart rate were also assessed in response to forehead cold and the Stroop Color-Word Conflict Test (CWT) before and after 30 min of rest or an acute bout of cycling exercise (∼50% VO₂ peak). Baseline FMD and stress responses were not different between smokers and nonsmokers. Compared to passive rest, exercise increased FMD and decreased arterial velocity and blood flow responses during the Stroop CWT and forehead cold in both groups. Overall, acute exercise improved endothelial function among smokers and nonsmokers despite increasing vascular resistance and reducing limb blood flow during neurovascular stress. PMID:21457274

  19. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition.

    PubMed

    Moreno-García, Jaime; Mauricio, Juan Carlos; Moreno, Juan; García-Martínez, Teresa

    2016-06-01

    In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis - based on cellular components and biological process GO terms - was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in "Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation" [1]. PMID:27104213

  20. Functional aspects of the photosynthetic light reactions in heat stressed Arabidopsis deficient in digalactosyl-diacylglycerol.

    PubMed

    Essemine, Jemâa; Govindachary, Sridharan; Ammar, Saïda; Bouzid, Sadok; Carpentier, Robert

    2011-09-01

    Plants are often submitted, in their natural environment, to various abiotic stresses such as heat stress. However, elevated temperature has a detrimental impact on overall plant growth and development. We have examined the physiological response of the dgd1-2 and dgd1-3 Arabidopsis mutants lacking 30-40% of digalactosyl-diacylglycerol (DGDG) exposed to heat constraint. These mutants, which grow similarly to wild type under normal conditions, were previously reported to be defective in basal thermotolerance as measured by cotyledon development. However their functional properties were not described. Chlorophyll fluorescence measurements and absorbance changes at 820nm were used to monitor photosystem II (PSII) and PSI activity, respectively. It was observed that both mutants have similar photosystem activities with some differences. The mutants were less able to use near saturation light energy and elicited higher rates of cyclic PSI electron flow compare to wild type. Arabidopsis leaves exposed to short-term (5min) mild (40°C) or strong (44°C) heat treatment have shown a decline in the operating effective quantum yield of PSII and in the proportion of active PSI reaction centers. However, cyclic PSI electron flow was enhanced. The establishment of the energy-dependent non-photochemical quenching of chlorophyll fluorescence was accelerated but its decline under illumination was inhibited. Furthermore, heat stress affected the process implicated in the redistribution of light excitation energy between the photosystems known as the light state transitions. All the effects of heat stress mentioned above were more intense in the mutant leaves with dgd1-3 being even more susceptible. The decreased DGDG content of the thylakoid membranes together with other lipid changes are proposed to influence the thermo-sensitivity of the light reactions of photosynthesis towards heat stress.

  1. Fracture transmissivity as a function of normal and shear stress: First results in Opalinus Clay

    NASA Astrophysics Data System (ADS)

    Cuss, Robert J.; Milodowski, Antoni; Harrington, Jon F.

    Fracture transmissivity has been investigated along an idealised fracture for the influence of normal stress and for the transient behaviour during a slow shear experiment. A linear trend for the relationship between effective stress and transmissivity has been proposed for normal loads between 1 and 5 MPa; as effective stress increases transmissivity decreases. Transmissivity was very low throughout the complete spectrum of effective stresses examined and was close to the permeability for intact Opalinus Clay, suggesting that the fracture had effectively closed. During active shearing at a constant normal load, fracture transmissivity was seen to initially reduce, probably due to clear smearing. A series of flux events were seen, with transmissivity increasing by a factor of four. Some of the flux events corresponded with dilation, whilst others did not. This suggests that the opening flow paths were localised and did not result in bulk dilatancy. During the course of the shear test the sample formed its own series of fractures and a complex pattern of deformation occurred along the fracture surface to a depth of less than 1 mm. The impression of the end of the injection hole clearly shows that the block underwent at least 5 mm of the total 6 mm of shear displacement. The injection of fluorescein showed that flow along the fracture was not uniformly radial, as one might expect for such an experimental geometry. At the time of injection there were a number of dominant flow features, mainly in the direction of shear and only perpendicular on one side of the fracture surface. Flow occurred along the original fracture surface as well as the newly formed shear surface, indicating multiple pathways in a complex manner. The evolution of fracture transmissivity is very complex, even along initially planar surfaces. Fracture transmissivity has been seen to be a function of normal stress and porewater pressure, and has also been seen to be a dynamic feature during shear.

  2. Tissue plasminogen activator and plasminogen mediate stress-induced decline of neuronal and cognitive functions in the mouse hippocampus.

    PubMed

    Pawlak, Robert; Rao, B S Shankaranarayana; Melchor, Jerry P; Chattarji, Sumantra; McEwen, Bruce; Strickland, Sidney

    2005-12-13

    Repeated stress can impair function in the hippocampus, a brain structure essential for learning and memory. Although behavioral evidence suggests that severe stress triggers cognitive impairment, as seen in major depression or posttraumatic stress disorder, little is known about the molecular mediators of these functional deficits in the hippocampus. We report here both pre- and postsynaptic effects of chronic stress, manifested as a reduction in the number of NMDA receptors, dendritic spines, and expression of growth-associated protein-43 in the cornu ammonis 1 region. Strikingly, the stress-induced decrease in NMDA receptors coincides spatially with sites of plasminogen activation, thereby predicting a role for tissue plasminogen activator (tPA) in this form of stress-induced plasticity. Consistent with this possibility, tPA-/- and plasminogen-/- mice are protected from stress-induced decrease in NMDA receptors and reduction in dendritic spines. At the behavioral level, these synaptic and molecular signatures of stress-induced plasticity are accompanied by impaired acquisition, but not retrieval, of hippocampal-dependent spatial learning, a deficit that is not exhibited by the tPA-/- and plasminogen-/- mice. These findings establish the tPA/plasmin system as an important mediator of the debilitating effects of prolonged stress on hippocampal function at multiple levels of neural organization.

  3. The influence of stress and gonadal hormones on neuronal structure and function.

    PubMed

    Farrell, Mollee R; Gruene, Tina M; Shansky, Rebecca M

    2015-11-01

    This article is part of a Special Issue "SBN 2014". The brain is highly plastic, allowing us to adapt and respond to environmental and physiological challenges and experiences. In this review, we discuss the relationships among alterations in dendritic arborization, spine morphology, and behavior due to stress exposure, endogenous hormone fluctuation, or exogenous hormonal manipulation. Very few studies investigate structure-function associations directly in the same cohort of animals, and there are notable inconsistencies in evidence of structure-function relationships in the prefrontal cortex and hippocampus. Moreover, little work has been done to probe the causal relationship between dendritic morphology and neuronal excitability, leaving only speculation about the adaptive versus maladaptive nature of experience-dependent dendritic remodeling. We propose that future studies combine electrophysiology with a circuit-level approach to better understand how dendritic structure contributes to neuronal functional properties and behavioral outcomes.

  4. The influence of stress and gonadal hormones on neuronal structure and function

    PubMed Central

    Farrell, Mollee R.; Gruene, Tina M.; Shansky, Rebecca M.

    2015-01-01

    The brain is highly plastic, allowing us to adapt and respond to environmental and physiological challenges and experiences. In this review, we discuss the relationships among alterations in dendritic arborization, spine morphology, and behavior due to stress exposure, endogenous hormone fluctuation, or exogenous hormonal manipulation. Very few studies investigate structure-function associations directly in the same cohort of animals, and there are notable inconsistencies in evidence of structure-function relationships in the prefrontal cortex and hippocampus. Moreover, little work has been done to probe the causal relationship between dendritic morphology and neuronal excitability, leaving only speculation about the adaptive versus maladaptive nature of experience-dependent dendritic remodeling. We propose that future studies combine electrophysiology with a circuit-level approach to better understand how dendritic structure contributes to neuronal functional properties and behavioral outcomes. PMID:25819727

  5. [Use of terahertz electromagnetic radiation at nitric oxide frequencies for the correction of thyroid functional state during stress].

    PubMed

    Kirichuk, V F; Tsymbal, A A

    2010-01-01

    The influence of terahertz electromagnetic radiation at nitric oxide frequencies (150.176-150.664 Ghz) on the functional activity of rat thyroid gland subjected to acute immobilization stress has been studied. It is shown that terahertz radiation totally normalizes thyroid activity in stressed animals within 30 min after application. PMID:20540354

  6. [Use of terahertz electromagnetic radiation at nitric oxide frequencies for the correction of thyroid functional state during stress].

    PubMed

    Kirichuk, V F; Tsymbal, A A

    2010-01-01

    The influence of terahertz electromagnetic radiation at nitric oxide frequencies (150.176-150.664 Ghz) on the functional activity of rat thyroid gland subjected to acute immobilization stress has been studied. It is shown that terahertz radiation totally normalizes thyroid activity in stressed animals within 30 min after application.

  7. An Indirect Effects Model of the Association between Poverty and Child Functioning: The Role of Children's Poverty-Related Stress

    ERIC Educational Resources Information Center

    Wadsworth, Martha E.; Raviv, Tali; Reinhard, Christine; Wolff, Brian; Santiago, Catherine DeCarlo; Einhorn, Lindsey

    2008-01-01

    The authors tested a theoretical model positing that poverty has an indirect effect on child and adolescent functioning through children's poverty-related stress. Path analyses with a multiethnic sample of 164 children aged 6 to 18 revealed that the stress associated with poverty, such as economic strain, family conflict, violence/trauma, and…

  8. Emerging Importance of Helicases in Plant Stress Tolerance: Characterization of Oryza sativa Repair Helicase XPB2 Promoter and Its Functional Validation in Tobacco under Multiple Stresses.

    PubMed

    Raikwar, Shailendra; Srivastava, Vineet K; Gill, Sarvajeet S; Tuteja, Renu; Tuteja, Narendra

    2015-01-01

    Genetic material always remains at the risk of spontaneous or induced damage which challenges the normal functioning of DNA molecule, thus, DNA repair is vital to protect the organisms against genetic damage. Helicases, the unique molecular motors, are emerged as prospective molecules to engineer stress tolerance in plants and are involved in nucleic acid metabolism including DNA repair. The repair helicase, XPB is an evolutionary conserved protein present in different organisms, including plants. Availability of few efficient promoters for gene expression in plants provoked us to study the promoter of XPB for better understanding of gene regulation under stress conditions. Here, we report the in silico analysis of novel stress inducible promoter of Oryza sativa XPB2 (OsXPB2). The in vivo validation of functionality/activity of OsXPB2 promoter under abiotic and hormonal stress conditions was performed by Agrobacterium-mediated transient assay in tobacco leaves using OsXPB2::GUS chimeric construct. The present research revealed that OsXPB2 promoter contains cis-elements accounting for various abiotic stresses (salt, dehydration, or cold) and hormone (Auxin, ABA, or MeJA) induced GUS expression/activity in the promoter-reporter assay. The promoter region of OsXPB2 contains CACG, GTAACG, CACGTG, CGTCA CCGCCGCGCT cis acting-elements which are reported to be salt, dehydration, cold, MeJA, or ABA responsive, respectively. Functional analysis was done by Agrobacterium-mediated transient assay using agroinfiltration in tobacco leaves, followed by GUS staining and fluorescence quantitative analyses. The results revealed high induction of GUS activity under multiple abiotic stresses as compared to mock treated control. The present findings suggest that OsXPB2 promoter is a multi-stress inducible promoter and has potential applications in sustainable crop production under abiotic stresses by regulating desirable pattern of gene expression. PMID:26734018

  9. Relief of Oxidative Stress Using Curcumin and Glutathione Functionalized ZnO Nanoparticles in HEK-293 Cell Line.

    PubMed

    Kumar, Amit; Zafaryab, Md; Umar, Ahmad; Rizvi, M M A; Fouad, H; Ansari, Z A; Ansari, S G

    2015-11-01

    To elucidate the effect of zinc oxide nanoparticles (ZnO-NPs) with different surface modifications in relieving the oxidative stress in cultured human embryonic kidney cells (HEK-293) following investigation was performed. Oxidative stress was artificially induced by hydrogen peroxide in HEK-293 cell culture and its management was studied. Alkyl amines modified ZnO-NPs with curcumin and reduced glutathione (GSH) functionalization was used in managing oxidative stress and had shown promising results. ZnO-NPs used in this study were synthesized via non-aqueous sol-gel method and FESEM characterisation showed them of spherical shape of about 20-50 nm size with amine, curcumin and GSH functionalization. UV-visible and FTIR spectroscopic characterizations confirmed functionalization of ZnO-NPs. Decrease in oxidative stress was found with the dose-dependent culture of HEK-293 cells with these functionalized ZnO-NPs. Cell viability and morphology, as observed using AFM and inverted microscope, was retained with the prescribed dosages of the functionalized nanoparticles while at higher dosages they caused cytotoxicity and death. Diethylamine (DEA) modified ZnO-NPs and their functionalization with GSH and curcumin were found more effective in managing oxidative stress in cells. Present study could help in designing economical and bio-compatible functionalized non-toxic nanoparticles designed for managing oxidative stress leading to possible therapeutical and medicinal uses. PMID:26554152

  10. [Effect of physical exercise on endothelial function, indicators of inflammation and oxidative stress].

    PubMed

    Skrypnik, Damian; Bogdański, Paweł; Madry, Edyta; Pupek-Musialik, Danuta; Walkowiak, Jarosław

    2014-02-01

    Endothelium plays an important role in regulation of the activity of inflammation and oxidative stress. Numerous studies have shown that physical training affects endothelial function. It is proven that regular physical activity reduces the seventy of inflammation and the risk of cardiovascular events. Changes observed in effect of physical activity include increase in production of nitric oxide (NO), a decrease of plaque volume, a decrease in vascular wall viscosity and an increase in diastolic coronary perfusion. It has been shown that exercise reduces cardiovascular risk in subjects with diabetes, metabolic syndrome, coronary heart disease and hypertension, as well as in healthy people. In above populations the benefits result from improved endothelial function. It has been proven that regular physical activity improves enzymatic antioxidant systems and the immune response. It is a result of the stimulating effect of muscle tissue micro-injuries and recruitment of various cell types of the inflammatory response and their migration deeper into the tissues. The biggest changes in the immune response are observed in prolonged aerobic exercise. Physical activity has a significant impact on endothelial function, intensity of inflammatory processes and exponents of oxidative stress. There is a need for further researches, in particular in order to determine the optimal model of training.

  11. Functional significance of point mutations in stress chaperone mortalin and their relevance to Parkinson disease.

    PubMed

    Wadhwa, Renu; Ryu, Jihoon; Ahn, Hyo Min; Saxena, Nishant; Chaudhary, Anupama; Yun, Chae-Ok; Kaul, Sunil C

    2015-03-27

    Mortalin/mtHsp70/Grp75 (mot-2), a heat shock protein 70 family member, is an essential chaperone, enriched in cancers, and has been shown to possess pro-proliferative and anti-apoptosis functions. An allelic form of mouse mortalin (mot-1) that differs by two amino acids, M618V and G624R, in the C terminus substrate-binding domain has been reported. Furthermore, genome sequencing of mortalin from Parkinson disease patients identified two missense mutants, R126W and P509S. In the present study, we investigated the significance of these mutations in survival, proliferation, and oxidative stress tolerance in human cells. Using mot-1 and mot-2 recombinant proteins and specific antibodies, we performed screening to find their binding proteins and then identified ribosomal protein L-7 (RPL-7) and elongation factor-1 α (EF-1α), which differentially bind to mot-1 and mot-2, respectively. We demonstrate that mot-1, R126W, or P509S mutant (i) lacks mot-2 functions involved in carcinogenesis, such as p53 inactivation and hTERT/hnRNP-K (heterogeneous nuclear ribonucleoprotein K) activation; (ii) causes increased level of endogenous oxidative stress; (iii) results in decreased tolerance of cells to exogenous oxidative stress; and (iv) shows differential binding and impact on the RPL-7 and EF-1α proteins. These factors may mediate the transformation of longevity/pro-proliferative function of mot-2 to the premature aging/anti-proliferative effect of mutants, and hence may have significance in cellular aging, Parkinson disease pathology, and prognosis. PMID:25645922

  12. Hydrogen sulfide protects endothelial nitric oxide function under conditions of acute oxidative stress in vitro.

    PubMed

    Al-Magableh, Mohammad R; Kemp-Harper, Barbara K; Ng, Hooi H; Miller, Alyson A; Hart, Joanne L

    2014-01-01

    The aim of this study was to examine the ability of H2S, released from NaHS to protect vascular endothelial function under conditions of acute oxidative stress by scavenging superoxide anions (O2(-)) and suppressing vascular superoxide anion production. O2(-) was generated in Krebs' solution by reacting hypoxanthine with xanthine oxidase (Hx-XO) or with the O2(-) generator pyrogallol to model acute oxidative stress in vitro. O2(-) generation was measured by lucigenin-enhanced chemiluminescence. Functional responses in mouse aortic rings were assessed using a small vessel myograph. NaHS scavenged O2(-) in a concentration-dependent manner. Isolated aortic rings exposed to either Hx-XO or pyrogallol displayed significantly attenuated maximum vasorelaxation responses to the endothelium-dependent vasodilator acetylcholine, and significantly reduced NO bioavailability, which was completely reversed if vessels were pre-incubated with NaHS (100 μM). NADPH-stimulated aortic O2(-) production was significantly attenuated by the NADPH oxidase inhibitor diphenyl iodonium. Prior treatment of vessels with NaHS (100 nM-100 μM; 30 min) inhibited NADPH-stimulated aortic O2(-) production in a concentration-dependent manner. This effect persisted when NaHS was washed out prior to measuring NADPH-stimulated O2(-) production. These data show for the first time that NaHS directly scavenges O2(-) and suppresses vascular NADPH oxidase-derived O2(-) production in vitro. Furthermore, these properties protect endothelial function and NO bioavailability in an in vitro model of acute oxidative stress. These results suggest that H2S can elicit vasoprotection by both scavenging O2(-) and by reducing vascular NADPH oxidase-derived O2(-) production.

  13. Function of S-nitrosoglutathione reductase (GSNOR) in plant development and under biotic/abiotic stress

    PubMed Central

    Leterrier, Marina; Chaki, Mounira; Airaki, Morad; Valderrama, Raquel; Palma, José M; Barroso, Juan B

    2011-01-01

    During the last decade, it was established that the class III alcohol dehydrogenase (ADH3) enzyme, also known as glutathione-dependent formaldehyde dehydrogenase (FALDH; EC 1.2.1.1), catalyzes the NADH-dependent reduction of S-nitrosoglutathione (GSNO) and therefore was also designated as GSNO reductase. This finding has opened new aspects in the metabolism of nitric oxide (NO) and NO-derived molecules where GSNO is a key component. In this article, current knowledge of the involvement and potential function of this enzyme during plant development and under biotic/abiotic stress is briefly reviewed. PMID:21543898

  14. Catecholamine responses to virtual combat: implications for post-traumatic stress and dimensions of functioning

    PubMed Central

    Highland, Krista B.; Costanzo, Michelle E.; Jovanovic, Tanja; Norrholm, Seth D.; Ndiongue, Rochelle B.; Reinhardt, Brian J.; Rothbaum, Barbara; Rizzo, Albert A.; Roy, Michael J.

    2015-01-01

    Posttraumatic stress disorder (PTSD) symptoms can result in functional impairment among service members (SMs), even in those without a clinical diagnosis. The variability in outcomes may be related to underlying catecholamine mechanisms. Individuals with PTSD tend to have elevated basal catecholamine levels, though less is known regarding catecholamine responses to trauma-related stimuli. We assessed whether catecholamine responses to a virtual combat environment impact the relationship between PTSD symptom clusters and elements of functioning. Eighty-seven clinically healthy SMs, within 2 months after deployment to Iraq or Afghanistan, completed self-report measures, viewed virtual-reality (VR) combat sequences, and had sequential blood draws. Norepinephrine responses to VR combat exposure moderated the relationship between avoidance symptoms and scales of functioning including physical functioning, physical-role functioning, and vitality. Among those with high levels of avoidance, norepinephrine change was inversely associated with functional status, whereas a positive correlation was observed for those with low levels of avoidance. Our findings represent a novel use of a virtual environment to display combat-related stimuli to returning SMs to elucidate mind-body connections inherent in their responses. The insight gained improves our understanding of post-deployment symptoms and quality of life in SMs and may facilitate enhancements in treatment. Further research is needed to validate these findings in other populations and to define the implications for treatment effectiveness. PMID:25852586

  15. Hypertonic stress regulates T cell function via pannexin-1 hemichannels and P2X receptors

    PubMed Central

    Woehrle, Tobias; Yip, Linda; Manohar, Monali; Sumi, Yuka; Yao, Yongli; Chen, Yu; Junger, Wolfgang G.

    2010-01-01

    Hypertonic saline (HS) resuscitation increases T cell function and inhibits posttraumatic T cell anergy, which can reduce immunosuppression and sepsis in trauma patients. We have previously shown that HS induces the release of cellular ATP and enhances T cell function. However, the mechanism by which HS induces ATP release and the subsequent regulation of T cell function by ATP remain poorly understood. In the present study, we show that inhibition of the gap junction hemichannel pannexin-1 (Panx1) blocks ATP release in response to HS, and HS exposure triggers significant changes in the expression of all P2X-type ATP receptors in Jurkat T cells. Blocking or silencing of Panx1 or of P2X1, P2X4, or P2X7 receptors blunts HS-induced p38 MAPK activation and the stimulatory effects of HS on TCR/CD28-induced IL-2 gene transcription. Moreover, treatment with HS or agonists of P2X receptors overcomes T cell suppression induced by the anti-inflammatory cytokine IL-10. These findings indicate that Panx1 hemichannels facilitate ATP release in response to hypertonic stress and that P2X1, P2X4, and P2X7 receptor activation enhances T cell function. We conclude that HS and P2 receptor agonists promote T cell function and thus, could be used to improve T cell function in trauma patients. PMID:20884646

  16. Catecholamine responses to virtual combat: implications for post-traumatic stress and dimensions of functioning.

    PubMed

    Highland, Krista B; Costanzo, Michelle E; Jovanovic, Tanja; Norrholm, Seth D; Ndiongue, Rochelle B; Reinhardt, Brian J; Rothbaum, Barbara; Rizzo, Albert A; Roy, Michael J

    2015-01-01

    Posttraumatic stress disorder (PTSD) symptoms can result in functional impairment among service members (SMs), even in those without a clinical diagnosis. The variability in outcomes may be related to underlying catecholamine mechanisms. Individuals with PTSD tend to have elevated basal catecholamine levels, though less is known regarding catecholamine responses to trauma-related stimuli. We assessed whether catecholamine responses to a virtual combat environment impact the relationship between PTSD symptom clusters and elements of functioning. Eighty-seven clinically healthy SMs, within 2 months after deployment to Iraq or Afghanistan, completed self-report measures, viewed virtual-reality (VR) combat sequences, and had sequential blood draws. Norepinephrine responses to VR combat exposure moderated the relationship between avoidance symptoms and scales of functioning including physical functioning, physical-role functioning, and vitality. Among those with high levels of avoidance, norepinephrine change was inversely associated with functional status, whereas a positive correlation was observed for those with low levels of avoidance. Our findings represent a novel use of a virtual environment to display combat-related stimuli to returning SMs to elucidate mind-body connections inherent in their responses. The insight gained improves our understanding of post-deployment symptoms and quality of life in SMs and may facilitate enhancements in treatment. Further research is needed to validate these findings in other populations and to define the implications for treatment effectiveness. PMID:25852586

  17. Residual stress evaluation in martensitic stainless steel as a function of gas quenching pressure using thermal neutrons

    NASA Astrophysics Data System (ADS)

    Doyle, Edward D.; Wong, Yat Choy; Ripley, Maurice I.

    2006-11-01

    The distribution of bulk residual stress was evaluated for two modified grades of martensitic stainless steels. Residual stress levels generated in the two steels were evaluated as a function of quenching gas pressure in vacuum heat treatment using neutron diffraction. It was observed that the levels of residual stress increased with increasing gas pressure, with the high hardenability grade showing the greater increase. However, quenching at 6 bar gas pressure resulted in a significant drop in the levels of residual stress, an observation that is interpreted in terms of the accommodation of high levels of strain by the presence of high levels of interlath retained austenite.

  18. Effects of yogurt containing Lactobacillus plantarum HOKKAIDO on immune function and stress markers.

    PubMed

    Nishimura, Mie; Ohkawara, Tatsuya; Tetsuka, Kyohei; Kawasaki, Yo; Nakagawa, Ryoji; Satoh, Hiroki; Sato, Yuji; Nishihira, Jun

    2016-07-01

    Lactobacillus plantarum HOKKAIDO (HOKKAIDO strain) was isolated from well-pickled vegetables in Hokkaido, Japan. We report a randomized, double-blind, placebo-controlled study evaluating the effects of L. plantarum HOKKAIDO on immune function and stress markers in 171 adult subjects. Subjects were divided into three groups: the L. plantarum HOKKAIDO yogurt group, the placebo-1 group who ingested yogurt without the HOKKAIDO strain, and the placebo-2 group who ingested a yogurt-like dessert without the HOKKAIDO strain. Hematological tests and body composition measurements were performed before and after 4 and 8 weeks of blinded ingestion. Although no significant differences in natural killer cell activity were observed, it was found that neutrophil ratio significantly decreased and lymphocytes tended to increase in the HOKKAIDO strain yogurt group compared with the yogurt-like dessert group. In addition, the neutrophil-to-lymphocyte ratio, a stress marker, tended to improve in the HOKKAIDO strain yogurt group compared with the yogurt-like dessert group. These results suggest that the ingestion of HOKKAIDO strain yogurt tends to improve immune activity and decrease stress markers. PMID:27419093

  19. Heat-stress-induced metabolic changes and altered male reproductive function.

    PubMed

    Hou, Yuanlong; Wang, Xiaoyan; Lei, Zhihai; Ping, Jihui; Liu, Jiajian; Ma, Zhiyu; Zhang, Zheng; Jia, Cuicui; Jin, Mengmeng; Li, Xiang; Li, Xiaoliang; Chen, Shaoqiu; Lv, Yingfang; Gao, Yingdong; Jia, Wei; Su, Juan

    2015-03-01

    Heat stress can cause systemic physiological and biochemical alterations in living organisms. In reproductive systems, heat stress induces germ cell loss and poor quality semen. However, until now, little has been known about such a complex regulation process, particularly in the perspective of metabolism. In this study, serum, hypothalamus, and epididymis samples derived from male SD (Sprague-Dawley) rats being exposed to high environmental temperature (40 °C) 2 h per day for 7 consecutive days were analyzed using metabonomics strategies based on GC/TOFMS. Differentially expressed metabolites reveal that the energy metabolism, amino acid neurotransmitters, and monoamine neurotransmitters pathways are associated with heat stress, in accordance with changes of the three upstream neuroendocrine system pathways in the SNS (sympathetic adrenergic system), hypothalamic pituitary adrenal axis (HPA), and hypothalamic pituitary testis axis (HPT) axis. Many of these metabolites, especially in the epididymis, were found to be up-regulated, presumably due to a self-preserving action to resist the environmental hot irritation to maintain normal functioning of the male reproductive system.

  20. Transcriptomic and Functional Analysis of NaCl-Induced Stress in Enterococcus faecalis

    PubMed Central

    Solheim, Margrete; La Rosa, Sabina Leanti; Mathisen, Thomas; Snipen, Lars G.; Nes, Ingolf F.; Brede, Dag Anders

    2014-01-01

    The robust physiology of Enterococcus faecalis facilitates tolerance to various stresses. We here report the transcriptional response of E. faecalis V583 to growth in the presence of 6.5% NaCl. Among the early responses observed was an immediate down-regulation of mscL, accompanied by an up-regulation of genes predicted to be involved in uptake of extracellular potassium and glycine betaine. The high NaCl concentration also induced expression of chaperons and cell envelope related traits, such as the enterococcal polysaccharide antigen (epa) locus. Functional genetic analysis revealed reduced salt stress resistance in both epaB and epaE mutants. The reduced salt resistance phenotype associated with the epaB mutant was restored by complementation, hence demonstrating a role of Epa in the physiological robustness of E. faecalis. Furthermore, we demonstrate that Epa confers increased resistance towards multiple cell envelope stress-inducing factors. Accordingly, these findings delineate a potential link between the robust nature of E. faecalis and its ability to perform as a human pathogen, and provide a new perspective on the mechanisms by which Epa contributes to virulence. Notably, the high NaCl concentration also resulted in strict repression of the gelE-sprE operon and impaired gelatinase activity. We demonstrate that NaCl antagonize the GBAP-pheromone dependent induction in a concentration dependent manner. PMID:24755907

  1. Transcriptomic and functional analysis of NaCl-induced stress in Enterococcus faecalis.

    PubMed

    Solheim, Margrete; La Rosa, Sabina Leanti; Mathisen, Thomas; Snipen, Lars G; Nes, Ingolf F; Brede, Dag Anders

    2014-01-01

    The robust physiology of Enterococcus faecalis facilitates tolerance to various stresses. We here report the transcriptional response of E. faecalis V583 to growth in the presence of 6.5% NaCl. Among the early responses observed was an immediate down-regulation of mscL, accompanied by an up-regulation of genes predicted to be involved in uptake of extracellular potassium and glycine betaine. The high NaCl concentration also induced expression of chaperons and cell envelope related traits, such as the enterococcal polysaccharide antigen (epa) locus. Functional genetic analysis revealed reduced salt stress resistance in both epaB and epaE mutants. The reduced salt resistance phenotype associated with the epaB mutant was restored by complementation, hence demonstrating a role of Epa in the physiological robustness of E. faecalis. Furthermore, we demonstrate that Epa confers increased resistance towards multiple cell envelope stress-inducing factors. Accordingly, these findings delineate a potential link between the robust nature of E. faecalis and its ability to perform as a human pathogen, and provide a new perspective on the mechanisms by which Epa contributes to virulence. Notably, the high NaCl concentration also resulted in strict repression of the gelE-sprE operon and impaired gelatinase activity. We demonstrate that NaCl antagonize the GBAP-pheromone dependent induction in a concentration dependent manner.

  2. Effects of yogurt containing Lactobacillus plantarum HOKKAIDO on immune function and stress markers.

    PubMed

    Nishimura, Mie; Ohkawara, Tatsuya; Tetsuka, Kyohei; Kawasaki, Yo; Nakagawa, Ryoji; Satoh, Hiroki; Sato, Yuji; Nishihira, Jun

    2016-07-01

    Lactobacillus plantarum HOKKAIDO (HOKKAIDO strain) was isolated from well-pickled vegetables in Hokkaido, Japan. We report a randomized, double-blind, placebo-controlled study evaluating the effects of L. plantarum HOKKAIDO on immune function and stress markers in 171 adult subjects. Subjects were divided into three groups: the L. plantarum HOKKAIDO yogurt group, the placebo-1 group who ingested yogurt without the HOKKAIDO strain, and the placebo-2 group who ingested a yogurt-like dessert without the HOKKAIDO strain. Hematological tests and body composition measurements were performed before and after 4 and 8 weeks of blinded ingestion. Although no significant differences in natural killer cell activity were observed, it was found that neutrophil ratio significantly decreased and lymphocytes tended to increase in the HOKKAIDO strain yogurt group compared with the yogurt-like dessert group. In addition, the neutrophil-to-lymphocyte ratio, a stress marker, tended to improve in the HOKKAIDO strain yogurt group compared with the yogurt-like dessert group. These results suggest that the ingestion of HOKKAIDO strain yogurt tends to improve immune activity and decrease stress markers.

  3. Heat-stress-induced metabolic changes and altered male reproductive function.

    PubMed

    Hou, Yuanlong; Wang, Xiaoyan; Lei, Zhihai; Ping, Jihui; Liu, Jiajian; Ma, Zhiyu; Zhang, Zheng; Jia, Cuicui; Jin, Mengmeng; Li, Xiang; Li, Xiaoliang; Chen, Shaoqiu; Lv, Yingfang; Gao, Yingdong; Jia, Wei; Su, Juan

    2015-03-01

    Heat stress can cause systemic physiological and biochemical alterations in living organisms. In reproductive systems, heat stress induces germ cell loss and poor quality semen. However, until now, little has been known about such a complex regulation process, particularly in the perspective of metabolism. In this study, serum, hypothalamus, and epididymis samples derived from male SD (Sprague-Dawley) rats being exposed to high environmental temperature (40 °C) 2 h per day for 7 consecutive days were analyzed using metabonomics strategies based on GC/TOFMS. Differentially expressed metabolites reveal that the energy metabolism, amino acid neurotransmitters, and monoamine neurotransmitters pathways are associated with heat stress, in accordance with changes of the three upstream neuroendocrine system pathways in the SNS (sympathetic adrenergic system), hypothalamic pituitary adrenal axis (HPA), and hypothalamic pituitary testis axis (HPT) axis. Many of these metabolites, especially in the epididymis, were found to be up-regulated, presumably due to a self-preserving action to resist the environmental hot irritation to maintain normal functioning of the male reproductive system. PMID:25607524

  4. Family functioning and mental health in runaway youth: association with posttraumatic stress symptoms.

    PubMed

    Thompson, Sanna J; Cochran, Gerald; Barczyk, Amanda N

    2012-10-01

    This study examined the direct effects of physical and sexual abuse, neglect, poor family communication and worries concerning family relationships, depression, anxiety, and dissociation on posttraumatic stress symptoms. Runaway youth were recruited from emergency youth shelters in New York and Texas. Interviews were completed with 350 youth who averaged 15 years of age. Structural equation modeling was used to examine family functioning, maltreatment, depression, dissociation, and anxiety in relation to posttraumatic stress symptoms. Results indicated that direct effects of family relationship worry to dissociation, β = .77, p < .001; depression, β = .85, p < .001; and anxiety, β = .90, p < .001 were significant, as were relationships between family communication and youth dissociation, β = .42, p < .001; depression, β = .46, p < .001; and anxiety, β = .32, p < .001. No significant effects of physical/sexual abuse or neglect were found. Higher levels of dissociation, β = .21, p < .001 and anxiety symptoms, β = .34, p = .01 were positively and significantly associated with posttraumatic stress symptoms, but depression was not. Findings underscore the critical role of family relationships in mental health symptoms experienced by runaway adolescents. PMID:23047596

  5. Low dose dobutamine stress echocardiography predicts the improvement of left ventricular systolic function in dilated cardiomyopathy

    PubMed Central

    Kitaoka, H; Takata, J; Yabe, T; Hitomi, N; Furuno, T; Doi, Y

    1999-01-01

    OBJECTIVE—To determine whether dobutamine stress echocardiography can predict the improvement of left ventricular systolic function in patients with dilated cardiomyopathy (DCM).
METHODS—Myocardial contractile reserve, as assessed by dobutamine stress echocardiography, was determined in 18 patients with DCM (mean (SD) age 53 (13) years, left ventricular ejection fraction (LVEF) 28 (10)%) and compared with changes in LVEF during a follow up period of 15 (8) months. The LVEF and regional left ventricular wall motion score (0, normal to 4, dyskinesis) of 12 segments in short axis and four chamber views were analysed before and after dobutamine infusion (5-20 µg/kg/min).
RESULTS—During a follow up period of 15 (8) months, a significant improvement in LVEF (> 20%) was found in seven patients but not in the remaining 11. Baseline haemodynamic findings were similar in both groups. Patients with an improvement in follow up LVEF showed a greater change in wall motion score from baseline during dobutamine infusion than patients with no improvement (at rest, 1.7 (0.4) v 1.9 (0.2), NS; dobutamine 10 µg/kg/min, 0.6 (0.4) v 1.2 (0.4), p < 0.05). The percentage change in LVEF during dobutamine infusion was also significantly greater in patients who showed improvement than in those who did not. The change in LVEF during the follow up period (follow up LVEF/baseline LVEF) correlated well with the change in LVEF during dobutamine stress (LVEF at rest/LVEF at dobutamine 10 µg/kg/min; r = 0.74, p < 0.001).
CONCLUSIONS—Changes in left ventricular systolic performance during low dose dobutamine stress echocardiography are a useful marker to predict the outcome of left ventricular systolic function in patients with DCM.


Keywords: dilated cardiomyopathy; dobutamine stress echocardiography; contractile reserve PMID:10212172

  6. Exploring the relationship between exposure to technological and gastrointestinal stress and probiotic functional properties of lactobacilli and bifidobacteria.

    PubMed

    Amund, O D

    2016-09-01

    Strains of Lactobacillus and Bifidobacterium are considered probiotic because of their associated potential health benefits. Probiotics are commonly administered orally via incorporation into food products. Microorganisms for use as probiotics encounter stress conditions, which include acid, bile, osmotic, oxidative, heat and cold stresses. These can occur during processing and storage and during passage through the gastrointestinal tract, and can affect viability. Probiotic bacteria have to remain viable to confer any health benefits. Therefore, the ability to withstand technological and gastrointestinal stresses is crucial probiotic selection criteria. While the stress tolerance mechanisms of lactobacilli and bifidobacteria are largely understood, the impact of exposure to stressful conditions on the functional properties of surviving probiotic microorganisms is not clear. This review explores the potentially positive and negative relationships between exposure to stress conditions and probiotic functional properties, such as resistance to gastric acid and bile, adhesion and colonization potential, and tolerance to antibiotics. Protective strategies can be employed to combat negative effects of stress on functional properties. However, further research is needed to ascertain synergistic relationships between exposure to stress and probiotic properties. PMID:27461506

  7. Exploring the relationship between exposure to technological and gastrointestinal stress and probiotic functional properties of lactobacilli and bifidobacteria.

    PubMed

    Amund, O D

    2016-09-01

    Strains of Lactobacillus and Bifidobacterium are considered probiotic because of their associated potential health benefits. Probiotics are commonly administered orally via incorporation into food products. Microorganisms for use as probiotics encounter stress conditions, which include acid, bile, osmotic, oxidative, heat and cold stresses. These can occur during processing and storage and during passage through the gastrointestinal tract, and can affect viability. Probiotic bacteria have to remain viable to confer any health benefits. Therefore, the ability to withstand technological and gastrointestinal stresses is crucial probiotic selection criteria. While the stress tolerance mechanisms of lactobacilli and bifidobacteria are largely understood, the impact of exposure to stressful conditions on the functional properties of surviving probiotic microorganisms is not clear. This review explores the potentially positive and negative relationships between exposure to stress conditions and probiotic functional properties, such as resistance to gastric acid and bile, adhesion and colonization potential, and tolerance to antibiotics. Protective strategies can be employed to combat negative effects of stress on functional properties. However, further research is needed to ascertain synergistic relationships between exposure to stress and probiotic properties.

  8. Analysis of corner cracks at hole by a 3-D weight function method with stresses from finite element method

    NASA Technical Reports Server (NTRS)

    Zhao, W.; Newman, J. C., Jr.; Sutton, M. A.; Wu, X. R.; Shivakumar, K. N.

    1995-01-01

    Stress intensity factors for quarter-elliptical corner cracks emanating from a circular hole are determined using a 3-D weight function method combined with a 3-D finite element method. The 3-D finite element method is used to analyze uncracked configuration and provide stress distribution in the region where crack is to occur. Using this stress distribution as input, the 3-D weight function method is used to determine stress intensity factors. Three different loading conditions, i.e. remote tension, remote bending and wedge loading, are considered for a wide range in geometrical parameters. The significance in using 3-D uncracked stress distribution and the difference between single and double corner cracks are studied. Typical crack opening displacements are also provided. Comparisons are made with solutions available in the literature.

  9. Boldine protects endothelial function in hyperglycemia-induced oxidative stress through an antioxidant mechanism.

    PubMed

    Lau, Yeh Siang; Tian, Xiao Yu; Huang, Yu; Murugan, Dharmani; Achike, Francis I; Mustafa, Mohd Rais

    2013-02-01

    Increased oxidative stress is involved in the pathogenesis and progression of diabetes. Antioxidants are therapeutically beneficial for oxidative stress-associated diseases. Boldine ([s]-2,9-dihydroxy-1,10-dimethoxyaporphine) is a major alkaloid present in the leaves and bark of the boldo tree (Peumus boldus Molina), with known an antioxidant activity. This study examined the protective effects of boldine against high glucose-induced oxidative stress in rat aortic endothelial cells (RAEC) and its mechanisms of vasoprotection related to diabetic endothelial dysfunction. In RAEC exposed to high glucose (30 mM) for 48 h, pre-treatment with boldine reduced the elevated ROS and nitrotyrosine formation, and preserved nitric oxide (NO) production. Pre-incubation with β-NAPDH reduced the acetylcholine-induced endothelium-dependent relaxation; this attenuation was reversed by boldine. Compared with control, endothelium-dependent relaxation in the aortas of streptozotocin (STZ)-treated diabetic rats was significantly improved by both acute (1 μM, 30 min) and chronic (20mg/kg/daily, i.p., 7 days) treatment with boldine. Intracellular superoxide and peroxynitrite formation measured by DHE fluorescence or chemiluminescence assay were higher in sections of aortic rings from diabetic rats compared with control. Chronic boldine treatment normalized ROS over-production in the diabetic group and this correlated with reduction of NAD(P)H oxidase subunits, NOX2 and p47(phox). The present study shows that boldine reversed the increased ROS formation in high glucose-treated endothelial cells and restored endothelial function in STZ-induced diabetes by inhibiting oxidative stress and thus increasing NO bioavailability. PMID:23178655

  10. Stress-related function of bHLH109 in somatic embryo induction in Arabidopsis.

    PubMed

    Nowak, Katarzyna; Gaj, Małgorzata D

    2016-04-01

    The bHLH109 gene of the bHLH family was identified among the transcription factor encoding genes that were differentially expressed in an embryogenic culture of Arabidopsis. A strong activation of bHLH109 expression was found to be associated with somatic embryogenesis (SE) induction. Several pieces of evidence suggested the involvement of bHLH109 in SE, including the high stimulation of the gene expression in SE-induced explants, which contrasts to the drastically lower level of the gene transcripts in the non-embryogenic callus and in tissue that is induced towards shoot regeneration via organogenesis. Moreover, in contrast to the overexpression of bHLH109, which has been indicated to enhance SE induction in a culture, the bhlh109 knock-out mutation was found to impair the embryogenic potential of explants. In order to identify the genes interacting with the bHLH109, the candidate co-expressed genes were identified in a yeast one hybrid assay. The in vitro regulatory interactions that were identified were verified through mutant and expression analysis. The results suggest that in SE bHLH109 acts as an activator of ECP63, a member of the LEA (LATE EMBRYOGENESIS ABUNDANT) family. Among the potential regulators of bHLH109, three candidates (At5g61620, bZIP4 and bZIP43) were indicated to possibly control bHLH109. The functions of all of the genes that are assumed to interact with bHLH109 are annotated to stress responses. Collectively, the results of the study provide new evidence that cell responses to stress that is imposed under in vitro conditions underlies the promotion of SE. bHLH109 may play a central role in the stress-related mechanism of SE induction via an increased accumulation of the LEA protein (ECP63), which results in the enhanced tolerance of the cells to stress. PMID:26973252

  11. Stress and decision making: neural correlates of the interaction between stress, executive functions, and decision making under risk.

    PubMed

    Gathmann, Bettina; Schulte, Frank P; Maderwald, Stefan; Pawlikowski, Mirko; Starcke, Katrin; Schäfer, Lena C; Schöler, Tobias; Wolf, Oliver T; Brand, Matthias

    2014-03-01

    Stress and additional load on the executive system, produced by a parallel working memory task, impair decision making under risk. However, the combination of stress and a parallel task seems to preserve the decision-making performance [e.g., operationalized by the Game of Dice Task (GDT)] from decreasing, probably by a switch from serial to parallel processing. The question remains how the brain manages such demanding decision-making situations. The current study used a 7-tesla magnetic resonance imaging (MRI) system in order to investigate the underlying neural correlates of the interaction between stress (induced by the Trier Social Stress Test), risky decision making (GDT), and a parallel executive task (2-back task) to get a better understanding of those behavioral findings. The results show that on a behavioral level, stressed participants did not show significant differences in task performance. Interestingly, when comparing the stress group (SG) with the control group, the SG showed a greater increase in neural activation in the anterior prefrontal cortex when performing the 2-back task simultaneously with the GDT than when performing each task alone. This brain area is associated with parallel processing. Thus, the results may suggest that in stressful dual-tasking situations, where a decision has to be made when in parallel working memory is demanded, a stronger activation of a brain area associated with parallel processing takes place. The findings are in line with the idea that stress seems to trigger a switch from serial to parallel processing in demanding dual-tasking situations.

  12. Functions of Nitric Oxide (NO) in Roots during Development and under Adverse Stress Conditions

    PubMed Central

    Corpas, Francisco J.; Barroso, Juan B.

    2015-01-01

    The free radical molecule, nitric oxide (NO), is present in the principal organs of plants, where it plays an important role in a wide range of physiological functions. Root growth and development are highly regulated by both internal and external factors such as nutrient availability, hormones, pattern formation, cell polarity and cell cycle control. The presence of NO in roots has opened up new areas of research on the role of NO, including root architecture, nutrient acquisition, microorganism interactions and the response mechanisms to adverse environmental conditions, among others. Additionally, the exogenous application of NO throughout the roots has the potential to counteract specific damages caused by certain stresses. This review aims to provide an up-to-date perspective on NO functions in the roots of higher plants. PMID:27135326

  13. On universality of stress-energy tensor correlation functions in supergravity [rapid communication

    NASA Astrophysics Data System (ADS)

    Buchel, Alex

    2005-03-01

    Using the Minkowski space AdS/CFT prescription we explicitly compute in the low-energy limit the two-point correlation function of the boundary stress-energy tensor in a large class of type IIB supergravity backgrounds with a regular translationally invariant horizon. The relevant set of supergravity backgrounds includes all geometries which can be interpreted via gauge theory/string theory correspondence as being holographically dual to finite temperature gauge theories in Minkowski space-times. The fluctuation-dissipation theorem relates this correlation function computation to the previously established universality of the shear viscosity from supergravity duals, and to the universality of the low energy absorption cross section for minimally coupled massless scalars into a general spherically symmetric black hole. It further generalizes the latter results for the supergravity black brane geometries with non-spherical horizons.

  14. Altered resting-state functional connectivity in post-traumatic stress disorder: a perfusion MRI study

    NASA Astrophysics Data System (ADS)

    Li, Baojuan; Liu, Jian; Liu, Yang; Lu, Hong-Bing; Yin, Hong

    2013-03-01

    The majority of studies on posttraumatic stress disorder (PTSD) so far have focused on delineating patterns of activations during cognitive processes. Recently, more and more researches have started to investigate functional connectivity in PTSD subjects using BOLD-fMRI. Functional connectivity analysis has been demonstrated as a powerful approach to identify biomarkers of different brain diseases. This study aimed to detect resting-state functional connectivity abnormities in patients with PTSD using arterial spin labeling (ASL) fMRI. As a completely non-invasive technique, ASL allows quantitative estimates of cerebral blood flow (CBF). Compared with BOLD-fMRI, ASL fMRI has many advantages, including less low-frequency signal drifts, superior functional localization, etc. In the current study, ASL images were collected from 10 survivors in mining disaster with recent onset PTSD and 10 survivors without PTSD. Decreased regional CBF in the right middle temporal gyrus, lingual gyrus, and postcentral gyrus was detected in the PTSD patients. Seed-based resting-state functional connectivity analysis was performed using an area in the right middle temporal gyrus as region of interest. Compared with the non-PTSD group, the PTSD subjects demonstrated increased functional connectivity between the right middle temporal gyrus and the right superior temporal gyrus, the left middle temporal gyrus. Meanwhile, decreased functional connectivity between the right middle temporal gyrus and the right postcentral gyrus, the right superior parietal lobule was also found in the PTSD patients. This is the first study which investigated resting-state functional connectivity in PTSD using ASL images. The results may provide new insight into the neural substrates of PTSD.

  15. Myocardial function improved by electromagnetic field induction of stress protein hsp70.

    PubMed

    George, Isaac; Geddis, Matthew S; Lill, Zachary; Lin, Hana; Gomez, Teodoro; Blank, Martin; Oz, Mehmet C; Goodman, Reba

    2008-09-01

    Studies on myocardial function have shown that hsp70, stimulated by an increase in temperature, leads to improved survival following ischemia-reperfusion (I-R). Low frequency electromagnetic fields (EMFs) also induce the stress protein hsp70, but without elevating temperature. We have examined the hemodynamic changes in concert with EMF pre-conditioning and the induction of hsp70 to determine whether improved myocardial function occurs following I-R injury in Sprague-Dawley rats. Animals were exposed to EMF (60 Hz, 8 microT) for 30 min prior to I-R. Ischemia was then induced by ligation of left anterior descending coronary artery (LAD) for 30 min, followed by 30 min of reperfusion. Blood and heart tissue levels for hsp70 were determined by Western blot and RNA transcription by rtPCR. Significant upregulation of the HSP70 gene and increased hsp70 levels were measured in response to EMF pre-exposures. Invasive hemodynamics, as measured using a volume conductance catheter, demonstrated significant recovery of systolic contractile function after 30 min of reperfusion following EMF exposure. Additionally, isovolemic relaxation, a measure of ventricular diastolic function, was markedly improved in EMF-treated animals. In conclusion, non-invasive EMF induction of hsp70 preserved myocardial function and has the potential to improve tolerance to ischemic injury.

  16. Israeli adolescents with ongoing exposure to terrorism: suicidal ideation, posttraumatic stress disorder, and functional impairment.

    PubMed

    Chemtob, Claude M; Pat-Horenczyk, Ruth; Madan, Anita; Pitman, Seth R; Wang, Yanping; Doppelt, Osnat; Burns, Kelly Dugan; Abramovitz, Robert; Brom, Daniel

    2011-12-01

    In this study, we examined the relationships among terrorism exposure, functional impairment, suicidal ideation, and probable partial or full posttraumatic stress disorder (PTSD) from exposure to terrorism in adolescents continuously exposed to this threat in Israel. A convenience sample of 2,094 students, aged 12 to 18, was drawn from 10 Israeli secondary schools. In terms of demographic factors, older age was associated with increased risk for suicidal ideation, OR = 1.33, 95% CI [1.09, 1.62], p < .01, but was protective against probable partial or full PTSD, OR = 0.72, 95% CI [0.54, 0.95], p < .05; female gender was associated with greater likelihood of probable partial or full PTSD, OR = 1.57, 95% CI [1.02, 2.40], p < .05. Exposure to trauma due to terrorism was associated with increased risk for each of the measured outcomes including probable partial or full PTSD, functional impairment, and suicidal ideation. When age, gender, level of exposure to terrorism, probable partial or full PTSD, and functional impairment were examined together, only terrorism exposure and functional impairment were associated with suicidal ideation. This study underscores the importance and feasibility of examining exposure to terrorism and functional impairment as risk factors for suicidal ideation.

  17. The protein targeting factor Get3 functions as ATP-independent chaperone under oxidative stress conditions.

    PubMed

    Voth, Wilhelm; Schick, Markus; Gates, Stephanie; Li, Sheng; Vilardi, Fabio; Gostimskaya, Irina; Southworth, Daniel R; Schwappach, Blanche; Jakob, Ursula

    2014-10-01

    Exposure of cells to reactive oxygen species (ROS) causes a rapid and significant drop in intracellular ATP levels. This energy depletion negatively affects ATP-dependent chaperone systems, making ROS-mediated protein unfolding and aggregation a potentially very challenging problem. Here we show that Get3, a protein involved in ATP-dependent targeting of tail-anchored (TA) proteins under nonstress conditions, turns into an effective ATP-independent chaperone when oxidized. Activation of Get3's chaperone function, which is a fully reversible process, involves disulfide bond formation, metal release, and its conversion into distinct, higher oligomeric structures. Mutational studies demonstrate that the chaperone activity of Get3 is functionally distinct from and likely mutually exclusive with its targeting function, and responsible for the oxidative stress-sensitive phenotype that has long been noted for yeast cells lacking functional Get3. These results provide convincing evidence that Get3 functions as a redox-regulated chaperone, effectively protecting eukaryotic cells against oxidative protein damage.

  18. Multi-stressor impacts on fungal diversity and ecosystem functions in streams: natural vs. anthropogenic stress.

    PubMed

    Tolkkinen, M; Mykrä, H; Annala, M; Markkola, A M; Vuori, K M; Muotka, T

    2015-03-01

    Biological assemblages are often subjected to multiple stressors emerging from both anthropogenic activities and naturally stressful conditions, and species' responses to simultaneous stressors may differ from those predicted based on the individual effects of each stressor alone. We studied the influence of land-use disturbance (forest drainage) on fungal decomposer assemblages and leaf decomposition rates in naturally harsh (low pH caused by black-shale dominated geology) vs. circumneutral streams. We used pyrosequencing to determine fungal richness and assemblage structure. Decomposition rates did not differ between circumneutral and naturally acidic reference sites. However, the effect of forest drainage on microbial decomposition was more pronounced in the naturally acidic streams than in circumneutral streams. Single-effect responses of fungal assemblages were mainly related to geology. Community similarity was significantly higher in the naturally acidic disturbed sites than in corresponding reference sites, suggesting that land-use disturbance simplifies fungal assemblages in naturally stressful conditions. Naturally acidic streams supported distinct fungal assemblages with many OTUs (operational taxonomic unit) unique to these streams. Our results indicate that fungal assemblages in streams are sensitive to both structural and functional impairment in response to multiple stressors. Anthropogenic degradation of naturally acidic streams may decrease regional fungal diversity and impair ecosystem functions, and these globally occurring environments therefore deserve special attention in conservation planning. PMID:26236864

  19. Impairment of Visual Function and Retinal ER Stress Activation in Wfs1-Deficient Mice

    PubMed Central

    Bonnet Wersinger, Delphine; Benkafadar, Nesrine; Jagodzinska, Jolanta; Hamel, Christian; Tanizawa, Yukio; Lenaers, Guy; Delettre, Cécile

    2014-01-01

    Wolfram syndrome is an early onset genetic disease (1/180,000) featuring diabetes mellitus and optic neuropathy, associated to mutations in the WFS1 gene. Wfs1−/− mouse model shows pancreatic beta cell atrophy, but its visual performance has not been investigated, prompting us to study its visual function and histopathology of the retina and optic nerve. Electroretinogram and visual evoked potentials (VEPs) were performed in Wfs1−/− and Wfs1+/+ mice at 3, 6, 9 and 12 months of age. Fundi were pictured with Micron III apparatus. Retinal ganglion cell (RGC) abundance was determined from Brn3a immunolabeling of retinal sections. RGC axonal loss was quantified by electron microscopy in transversal optic nerve sections. Endoplasmic reticulum stress was assessed using immunoglobulin binding protein (BiP), protein disulfide isomerase (PDI) and inositol-requiring enzyme 1 alpha (Ire1α) markers. Electroretinograms amplitudes were slightly reduced and latencies increased with time in Wfs1−/− mice. Similarly, VEPs showed decreased N+P amplitudes and increased N-wave latency. Analysis of unfolded protein response signaling revealed an activation of endoplasmic reticulum stress in Wfs1−/− mutant mouse retinas. Altogether, progressive VEPs alterations with minimal neuronal cell loss suggest functional alteration of the action potential in the Wfs1−/− optic pathways. PMID:24823368

  20. Glucocorticoid mechanisms of functional connectivity changes in stress-related neuropsychiatric disorders

    PubMed Central

    Hall, Baila S.; Moda, Rachel N.; Liston, Conor

    2014-01-01

    Stress—especially chronic, uncontrollable stress—is an important risk factor for many neuropsychiatric disorders. The underlying mechanisms are complex and multifactorial, but they involve correlated changes in structural and functional measures of neuronal connectivity within cortical microcircuits and across neuroanatomically distributed brain networks. Here, we review evidence from animal models and human neuroimaging studies implicating stress-associated changes in functional connectivity in the pathogenesis of PTSD, depression, and other neuropsychiatric conditions. Changes in fMRI measures of corticocortical connectivity across distributed networks may be caused by specific structural alterations that have been observed in the prefrontal cortex, hippocampus, and other vulnerable brain regions. These effects are mediated in part by glucocorticoids, which are released from the adrenal gland in response to a stressor and also oscillate in synchrony with diurnal rhythms. Recent work indicates that circadian glucocorticoid oscillations act to balance synapse formation and pruning after learning and during development, and chronic stress disrupts this balance. We conclude by considering how disrupted glucocorticoid oscillations may contribute to the pathophysiology of depression and PTSD in vulnerable individuals, and how circadian rhythm disturbances may affect non-psychiatric populations, including frequent travelers, shift workers, and patients undergoing treatment for autoimmune disorders. PMID:25729760

  1. [Effects of copper stress on the function of arbuscular mycorrhizal fungi community].

    PubMed

    Yang, Ru-yi; Zan, Shu-ting; Li, Jing; Su, Nan-nan; Sun, Wen-wen; Guo, Fu-yu; Zhou, Gang

    2015-05-01

    The functional differences of arbuscular mycorrhizal fungi (AMF) isolates from different sources have been extensively investigated in the last two decades. However, previous studies were mostly based on individual AMF species and the community level comparison was not addressed properly. Furthermore, many studies did not distinguish the difference between the effects of AMF source and community structure on their function, let alone concerned the significance of host plant. This study evaluated the effects of copper (Cu) stress on AMF community structure and compared the differences of AMF communities from Cu contaminated and uncontaminated substrates on performance of Zea mays through two short-term greenhouse pot culture experiments. The results showed that spore abundance and composition of AMF communities were changed dramatically under Cu stress compared with the control. The communities dominated by Rhizophagus intraradices and Claroideoglomus etunicatum from Cu contaminated soils conferred more benefits on Z. mays in terms of plant growth and physiological properties relative to that from control governed by Funneliformis mosseae.

  2. Effects of Exercise Intensity on Postexercise Endothelial Function and Oxidative Stress

    PubMed Central

    McClean, Conor; Harris, Ryan A.; Brown, Malcolm; Brown, John C.; Davison, Gareth W.

    2015-01-01

    Purpose. To measure endothelial function and oxidative stress immediately, 90 minutes, and three hours after exercise of varying intensities. Methods. Sixteen apparently healthy men completed three exercise bouts of treadmill running for 30 minutes at 55% V˙O2max (mild); 20 minutes at 75% V˙O2max (moderate); or 5 minutes at 100% V˙O2max (maximal) in random order. Brachial artery flow-mediated dilation (FMD) was assessed with venous blood samples drawn for measurement of endothelin-1 (ET-1), lipid hydroperoxides (LOOHs), and lipid soluble antioxidants. Results. LOOH increased immediately following moderate exercise (P < 0.05). ET-1 was higher immediately after exercise and 3 hours after exercise in the mild trial compared to maximal one (P < 0.05). Transient decreases were detected for ΔFMD/ShearAUC from baseline following maximal exercise, but it normalised at 3 hours after exercise (P < 0.05). Shear rate was higher immediately after exercise in the maximal trial compared to mild exercise (P < 0.05). No changes in baseline diameter, peak diameter, absolute change in diameter, or FMD were observed following any of the exercise trials (P > 0.05). Conclusions. Acute exercise at different intensities elicits varied effects on oxidative stress, shear rate, and ET-1 that do not appear to mediate changes in endothelial function measured by FMD. PMID:26583061

  3. Structural and functional changes in the insulin molecule produced by oxidative stress.

    PubMed

    Medina-Navarro, Rafael; Guzmán-Grenfell, Alberto M; Olivares-Corichi, Ivonne; Hicks, Juan J

    2010-01-01

    The change produced by oxidative stress on proteins (cross-links, backbone cleavage, amino acid modification) generates structural changes with a wide range of consequences such as increased propensity to the aggregation or proteolysis, altered immunogenicity and frequently enzymatic and binding inhibition. Insulin is particularly sensitive to conformational changes, aggregation and cross-linking; any change on insulin could impair its function. We have examined the biological activity of insulin modified by hydroxyl radical and exposed to acrolein in rats and adiposites. We found out important changes that we have shown as prototype of possible effect of oxidative stress on the structural and functional damage to insulin. Whereas, hydroxyl radical and acrolein both have diminished the hypoglycemic effect of insulin in vivo, and the effect of acrolein seems be to involved in carbonylation and not derived from inter-molecular cross-links formation or aggregates. The effect was highly stimulated at alkaline pH, concomitant with carbonyl formation and then probably aldolic condensation type reaction-dependent. Hydroxyls radical generates tyrosine derivative formation and introduces non aldehyde dependent carbonyls in the insulin molecule.

  4. Evaluation of effective-stress-function algorithm for nuclear fuel simulation

    SciTech Connect

    Kim, H. C.; Yang, Y. S.; Koo, Y. H.

    2013-07-01

    In a pressurized water reactor (PWR), the mechanical integrity of nuclear fuel is the most critical issue as it is an important barrier for fission products released into the environment. The integrity of zirconium cladding that surrounds uranium oxide can be threatened during off-normal operation owing to a pellet-cladding mechanical interaction (PCMI). To analyze the fuel and cladding behavior during off-operation, the fuel performance code should calculate an inelastic analysis in two - or three-dimensional calculations. In this paper, the effective stress function (ESF) algorithm based on a two-dimensional FE module has been implemented to simulate the inelastic behavior of the cladding with stability and accuracy. The ESF algorithm solves the governing equations of the inelastic constitutive behavior by calculating the zero of the appropriate effective-stress-function. To verify the accuracy of the ESF algorithm for an inelastic analysis, a code-to-code benchmark was performed using the commercial FE code, ANSYS 13.0. To demonstrate the stability and convergence of the implemented algorithm, the number of iterations in the ESF algorithm was compared with that in a sequential algorithm in the case of an inelastic problem. Consequently, the evaluation results demonstrate that the implemented ESF algorithm improves the efficiency of the computation without a loss of accuracy for an inelastic analysis. (authors)

  5. Functional value of elytra under various stresses in the red flour beetle, Tribolium castaneum

    PubMed Central

    Linz, David M.; Hu, Alan W.; Sitvarin, Michael I.; Tomoyasu, Yoshinori

    2016-01-01

    Coleoptera (beetles) is a massively successful order of insects, distinguished by their evolutionarily modified forewings called elytra. These structures are often presumed to have been a major driving force for the successful radiation of this taxon, by providing beetles with protection against a variety of harsh environmental factors. However, few studies have directly demonstrated the functional significance of the elytra against diverse environmental challenges. Here, we sought to empirically test the function of the elytra using Tribolium castaneum (the red flour beetle) as a model. We tested four categories of stress on the beetles: physical damage to hindwings, predation, desiccation, and cold shock. We found that, in all categories, the presence of elytra conferred a significant advantage compared to those beetles with their elytra experimentally removed. This work provides compelling quantitative evidence supporting the importance of beetle forewings in tolerating a variety of environmental stresses, and gives insight into how the evolution of elytra have facilitated the remarkable success of beetle radiation. PMID:27708390

  6. Epigenetics, Stress, and Their Potential Impact on Brain Network Function: A Focus on the Schizophrenia Diatheses

    PubMed Central

    Diwadkar, Vaibhav A.; Bustamante, Angela; Rai, Harinder; Uddin, Monica

    2014-01-01

    The recent sociodevelopmental cognitive model of schizophrenia/psychosis is a highly influential and compelling compendium of research findings. Here, we present logical extensions to this model incorporating ideas drawn from epigenetic mediation of psychiatric disease, and the plausible effects of epigenetics on the emergence of brain network function and dysfunction in adolescence. We discuss how gene–environment interactions, effected by epigenetic mechanisms, might in particular mediate the stress response (itself heavily implicated in the emergence of schizophrenia). Next, we discuss the plausible relevance of this framework for adolescent genetic risk populations, a risk group characterized by vexing and difficult-to-explain heterogeneity. We then discuss how exploring relationships between epigenetics and brain network dysfunction (a strongly validated finding in risk populations) can enhance understanding of the relationship between stress, epigenetics, and functional neurobiology, and the relevance of this relationship for the eventual emergence of schizophrenia/psychosis. We suggest that these considerations can expand the impact of models such as the sociodevelopmental cognitive model, increasing their explanatory reach. Ultimately, integration of these lines of research may enhance efforts of early identification, intervention, and treatment in adolescents at-risk for schizophrenia. PMID:25002852

  7. U0126 protects cells against oxidative stress independent of its function as a MEK inhibitor.

    PubMed

    Ong, Qunxiang; Guo, Shunling; Zhang, Kai; Cui, Bianxiao

    2015-01-21

    U0126 is a potent and selective inhibitor of MEK1 and MEK2 kinases. It has been widely used as an inhibitor for the Ras/Raf/MEK/ERK signaling pathway with over 5000 references on the NCBI PubMed database. In particular, U0126 has been used in a number of studies to show that inhibition of the Raf/MEK/ERK pathway protects neuronal cells against oxidative stress. Here, we report that U0126 can function as an antioxidant that protects PC12 cells against a number of different oxidative-stress inducers. This protective effect of U0126 is independent of its function as a MEK inhibitor, as several other MEK inhibitors failed to show similar protective effects. U0126 reduces reactive oxygen species (ROS) in cells. We further demonstrate that U0126 is a direct ROS scavenger in vitro, and the oxidation products of U0126 exhibit fluorescence. Our finding that U0126 is a strong antioxidant signals caution for its future usage as a MEK inhibitor and for interpreting some previous results. PMID:25544156

  8. Oxidative stress generated during monensin treatment contributes to altered Toxoplasma gondii mitochondrial function

    PubMed Central

    Charvat, Robert A.; Arrizabalaga, Gustavo

    2016-01-01

    The ionophore monensin displays potent activities against several coccidian parasites of veterinary and medical importance including the opportunistic pathogen of humans, Toxoplasma gondii. While monensin is used widely in animals, toxicity impedes its use in humans. Nonetheless, given its potency, understanding its mode of action would reveal vulnerable aspects of the parasite that can be exploited for drug development. We previously established that monensin induces Toxoplasma to undergo cell cycle arrest and an autophagy-like cell death. Interestingly, these effects are dependent on the mitochondrion-localized TgMSH-1 protein, suggesting that monensin disrupts mitochondrial function. We demonstrate that monensin treatment results in decreased mitochondrial membrane potential and altered morphology. These effects are mitigated by the antioxidant compound N-acetyl-cysteine suggesting that monensin causes an oxidative stress, which was indeed the case based on direct detection of reactive oxygen species. Moreover, over-expression of the antioxidant proteins glutaredoxin and peroxiredoxin 2 protect Toxoplasma from the deleterious effects of monensin. Thus, our studies show that the effects of monensin on Toxoplasma are due to a disruption of mitochondrial function caused by the induction of an oxidative stress and implicate parasite redox biology as a viable target for the development of drugs against Toxoplasma and related pathogenic parasites. PMID:26976749

  9. Multi-stressor impacts on fungal diversity and ecosystem functions in streams: natural vs. anthropogenic stress.

    PubMed

    Tolkkinen, M; Mykrä, H; Annala, M; Markkola, A M; Vuori, K M; Muotka, T

    2015-03-01

    Biological assemblages are often subjected to multiple stressors emerging from both anthropogenic activities and naturally stressful conditions, and species' responses to simultaneous stressors may differ from those predicted based on the individual effects of each stressor alone. We studied the influence of land-use disturbance (forest drainage) on fungal decomposer assemblages and leaf decomposition rates in naturally harsh (low pH caused by black-shale dominated geology) vs. circumneutral streams. We used pyrosequencing to determine fungal richness and assemblage structure. Decomposition rates did not differ between circumneutral and naturally acidic reference sites. However, the effect of forest drainage on microbial decomposition was more pronounced in the naturally acidic streams than in circumneutral streams. Single-effect responses of fungal assemblages were mainly related to geology. Community similarity was significantly higher in the naturally acidic disturbed sites than in corresponding reference sites, suggesting that land-use disturbance simplifies fungal assemblages in naturally stressful conditions. Naturally acidic streams supported distinct fungal assemblages with many OTUs (operational taxonomic unit) unique to these streams. Our results indicate that fungal assemblages in streams are sensitive to both structural and functional impairment in response to multiple stressors. Anthropogenic degradation of naturally acidic streams may decrease regional fungal diversity and impair ecosystem functions, and these globally occurring environments therefore deserve special attention in conservation planning.

  10. Differential changes of metabolic brain activity and interregional functional coupling in prefronto-limbic pathways during different stress conditions: functional imaging in freely behaving rodent pups.

    PubMed

    Bock, Jörg; Riedel, Anett; Braun, Katharina

    2012-01-01

    The trumpet-tailed rat or degu (Octodon degus) is an established model to investigate the consequences of early stress on the development of emotional brain circuits and behavior. The aim of this study was to identify brain circuits, that respond to different stress conditions and to test if acute stress alters functional coupling of brain activity among prefrontal and limbic regions. Using functional imaging (2-Fluoro-deoxyglucose method) in 8-day-old male degu pups the following stress conditions were compared: (A) pups together with parents and siblings (control), (B) separation of the litter from the parents, (C) individual separation from parents and siblings, and (D) individual separation and presentation of maternal calls. Condition (B) significantly downregulated brain activity in the prefrontal cortex, hippocampus, nucleus accumbens (NAcc), and sensory areas compared to controls. Activity decrease was even more pronounced during condition (C), where, in contrast to all other regions, activity in the PAG was increased. Interestingly, brain activity in stress-associated brain regions such as the amygdala and habenula was not affected. In condition (D) maternal vocalizations "reactivated" brain activity in the cingulate and precentral medial cortex, NAcc, and striatum and in sensory areas. In contrast, reduced activity was measured in the prelimbic and infralimbic cortex (IL) and in the hippocampus and amygdala. Correlation analysis revealed complex, region- and situation-specific changes of interregional functional coupling among prefrontal and limbic brain regions during stress exposure. We show here for the first time that early life stress results in a widespread reduction of brain activity in the infant brain and changes interregional functional coupling. Moreover, maternal vocalizations can partly buffer stress-induced decrease in brain activity in some regions and evoked very different functional coupling patterns compared to the three other conditions.

  11. Heme Oxygenase-1 Induction Improves Cardiac Function following Myocardial Ischemia by Reducing Oxidative Stress

    PubMed Central

    Issan, Yossi; Kornowski, Ran; Aravot, Dan; Shainberg, Asher; Laniado-Schwartzman, Michal; Sodhi, Komal; Abraham, Nader G.; Hochhauser, Edith

    2014-01-01

    Background Oxidative stress plays a key role in exacerbating diabetes and cardiovascular disease. Heme oxygenase-1 (HO-1), a stress response protein, is cytoprotective, but its role in post myocardial infarction (MI) and diabetes is not fully characterized. We aimed to investigate the protection and the mechanisms of HO-1 induction in cardiomyocytes subjected to hypoxia and in diabetic mice subjected to LAD ligation. Methods In vitro: cultured cardiomyocytes were treated with cobalt-protoporphyrin (CoPP) and tin protoporphyrin (SnPP) prior to hypoxic stress. In vivo: CoPP treated streptozotocin-induced diabetic mice were subjected to LAD ligation for 2/24 h. Cardiac function, histology, biochemical damage markers and signaling pathways were measured. Results HO-1 induction lowered release of lactate dehydrogenase (LDH) and creatine phospho kinase (CK), decreased propidium iodide staining, improved cell morphology and preserved mitochondrial membrane potential in cardiomyocytes. In diabetic mice, Fractional Shortening (FS) was lower than non-diabetic mice (35±1%vs.41±2, respectively p<0.05). CoPP-treated diabetic animals improved cardiac function (43±2% p<0.01), reduced CK, Troponin T levels and infarct size compared to non-treated diabetic mice (P<0.01, P<0.001, P<0.01 respectively). CoPP-enhanced HO-1 protein levels and reduced oxidative stress in diabetic animals, as indicated by the decrease in superoxide levels in cardiac tissues and plasma TNFα levels (p<0.05). The increased levels of HO-1 by CoPP treatment after LAD ligation led to a shift of the Bcl-2/bax ratio towards the antiapoptotic process (p<0.05). CoPP significantly increased the expression levels of pAKT and pGSK3β (p<0.05) in cardiomyocytes and in diabetic mice with MI. SnPP abolished CoPP's cardioprotective effects. Conclusions HO-1 induction plays a role in cardioprotection against hypoxic damage in cardiomyocytes and in reducing post ischemic cardiac damage in the diabetic heart as proved by

  12. Expansion and Function of Repeat Domain Proteins During Stress and Development in Plants

    PubMed Central

    Sharma, Manisha; Pandey, Girdhar K.

    2016-01-01

    The recurrent repeats having conserved stretches of amino acids exists across all domains of life. Subsequent repetition of single sequence motif and the number and length of the minimal repeating motifs are essential characteristics innate to these proteins. The proteins with tandem peptide repeats are essential for providing surface to mediate protein–protein interactions for fundamental biological functions. Plants are enriched in tandem repeat containing proteins typically distributed into various families. This has been assumed that the occurrence of multigene repeats families in plants enable them to cope up with adverse environmental conditions and allow them to rapidly acclimatize to these conditions. The evolution, structure, and function of repeat proteins have been studied in all kingdoms of life. The presence of repeat proteins is particularly profuse in multicellular organisms in comparison to prokaryotes. The precipitous expansion of repeat proteins in plants is presumed to be through internal tandem duplications. Several repeat protein gene families have been identified in plants. Such as Armadillo (ARM), Ankyrin (ANK), HEAT, Kelch-like repeats, Tetratricopeptide (TPR), Leucine rich repeats (LRR), WD40, and Pentatricopeptide repeats (PPR). The structure and functions of these repeat proteins have been extensively studied in plants suggesting a critical role of these repeating peptides in plant cell physiology, stress and development. In this review, we illustrate the structural, functional, and evolutionary prospects of prolific repeat proteins in plants. PMID:26793205

  13. Expansion and Function of Repeat Domain Proteins During Stress and Development in Plants.

    PubMed

    Sharma, Manisha; Pandey, Girdhar K

    2015-01-01

    The recurrent repeats having conserved stretches of amino acids exists across all domains of life. Subsequent repetition of single sequence motif and the number and length of the minimal repeating motifs are essential characteristics innate to these proteins. The proteins with tandem peptide repeats are essential for providing surface to mediate protein-protein interactions for fundamental biological functions. Plants are enriched in tandem repeat containing proteins typically distributed into various families. This has been assumed that the occurrence of multigene repeats families in plants enable them to cope up with adverse environmental conditions and allow them to rapidly acclimatize to these conditions. The evolution, structure, and function of repeat proteins have been studied in all kingdoms of life. The presence of repeat proteins is particularly profuse in multicellular organisms in comparison to prokaryotes. The precipitous expansion of repeat proteins in plants is presumed to be through internal tandem duplications. Several repeat protein gene families have been identified in plants. Such as Armadillo (ARM), Ankyrin (ANK), HEAT, Kelch-like repeats, Tetratricopeptide (TPR), Leucine rich repeats (LRR), WD40, and Pentatricopeptide repeats (PPR). The structure and functions of these repeat proteins have been extensively studied in plants suggesting a critical role of these repeating peptides in plant cell physiology, stress and development. In this review, we illustrate the structural, functional, and evolutionary prospects of prolific repeat proteins in plants. PMID:26793205

  14. Memory CD8(+) T Cells Require Increased Concentrations of Acetate Induced by Stress for Optimal Function.

    PubMed

    Balmer, Maria L; Ma, Eric H; Bantug, Glenn R; Grählert, Jasmin; Pfister, Simona; Glatter, Timo; Jauch, Annaïse; Dimeloe, Sarah; Slack, Emma; Dehio, Philippe; Krzyzaniak, Magdalena A; King, Carolyn G; Burgener, Anne-Valérie; Fischer, Marco; Develioglu, Leyla; Belle, Réka; Recher, Mike; Bonilla, Weldy V; Macpherson, Andrew J; Hapfelmeier, Siegfried; Jones, Russell G; Hess, Christoph

    2016-06-21

    How systemic metabolic alterations during acute infections impact immune cell function remains poorly understood. We found that acetate accumulates in the serum within hours of systemic bacterial infections and that these increased acetate concentrations are required for optimal memory CD8(+) T cell function in vitro and in vivo. Mechanistically, upon uptake by memory CD8(+) T cells, stress levels of acetate expanded the cellular acetyl-coenzyme A pool via ATP citrate lyase and promoted acetylation of the enzyme GAPDH. This context-dependent post-translational modification enhanced GAPDH activity, catalyzing glycolysis and thus boosting rapid memory CD8(+) T cell responses. Accordingly, in a murine Listeria monocytogenes model, transfer of acetate-augmented memory CD8(+) T cells exerted superior immune control compared to control cells. Our results demonstrate that increased systemic acetate concentrations are functionally integrated by CD8(+) T cells and translate into increased glycolytic and functional capacity. The immune system thus directly relates systemic metabolism with immune alertness. PMID:27212436

  15. Stress-responsive expression patterns and functional characterization of cold shock domain proteins in cabbage (Brassica rapa) under abiotic stress conditions.

    PubMed

    Choi, Min Ji; Park, Ye Rin; Park, Su Jung; Kang, Hunseung

    2015-11-01

    Although the functional roles of cold shock domain proteins (CSDPs) have been demonstrated during the growth, development, and stress adaptation of Arabidopsis (Arabidopsis thaliana), rice (Oryza sativa), and wheat (Triticum aestivum), the functions of CSDPs in other plants species, including cabbage (Brassica rapa), are largely unknown. To gain insight into the roles of CSDPs in cabbage under stress conditions, the genes encoding CSDPs in cabbage were isolated, and the functional roles of CSDPs in response to environmental stresses were analyzed. Real-time RT-PCR analysis revealed that the levels of BrCSDP transcripts increased during cold, salt, or drought stress, as well as upon ABA treatment. Among the five BrCSDP genes found in the cabbage genome, one CSDP (BRU12051), named BrCSDP3, was unique in that it is localized to the chloroplast as well as to the nucleus. Ectopic expression of BrCSDP3 in Arabidopsis resulted in accelerated seed germination and better seedling growth compared to the wild-type plants under high salt or dehydration stress conditions, and in response to ABA treatment. BrCSDP3 did not affect the splicing of intron-containing genes and processing of rRNAs in the chloroplast. BrCSDP3 had the ability to complement RNA chaperone-deficient Escherichia coli mutant cells under low temperatures as well as DNA- and RNA-melting abilities, suggesting that it possesses RNA chaperone activity. Taken together, these results suggest that BrCSDP3, harboring RNA chaperone activity, plays a role as a positive regulator in seed germination and seedling growth under stress conditions.

  16. Stress-responsive expression patterns and functional characterization of cold shock domain proteins in cabbage (Brassica rapa) under abiotic stress conditions.

    PubMed

    Choi, Min Ji; Park, Ye Rin; Park, Su Jung; Kang, Hunseung

    2015-11-01

    Although the functional roles of cold shock domain proteins (CSDPs) have been demonstrated during the growth, development, and stress adaptation of Arabidopsis (Arabidopsis thaliana), rice (Oryza sativa), and wheat (Triticum aestivum), the functions of CSDPs in other plants species, including cabbage (Brassica rapa), are largely unknown. To gain insight into the roles of CSDPs in cabbage under stress conditions, the genes encoding CSDPs in cabbage were isolated, and the functional roles of CSDPs in response to environmental stresses were analyzed. Real-time RT-PCR analysis revealed that the levels of BrCSDP transcripts increased during cold, salt, or drought stress, as well as upon ABA treatment. Among the five BrCSDP genes found in the cabbage genome, one CSDP (BRU12051), named BrCSDP3, was unique in that it is localized to the chloroplast as well as to the nucleus. Ectopic expression of BrCSDP3 in Arabidopsis resulted in accelerated seed germination and better seedling growth compared to the wild-type plants under high salt or dehydration stress conditions, and in response to ABA treatment. BrCSDP3 did not affect the splicing of intron-containing genes and processing of rRNAs in the chloroplast. BrCSDP3 had the ability to complement RNA chaperone-deficient Escherichia coli mutant cells under low temperatures as well as DNA- and RNA-melting abilities, suggesting that it possesses RNA chaperone activity. Taken together, these results suggest that BrCSDP3, harboring RNA chaperone activity, plays a role as a positive regulator in seed germination and seedling growth under stress conditions. PMID:26263516

  17. DNA Replication Stress Phosphoproteome Profiles Reveal Novel Functional Phosphorylation Sites on Xrs2 in Saccharomyces cerevisiae.

    PubMed

    Huang, Dongqing; Piening, Brian D; Kennedy, Jacob J; Lin, Chenwei; Jones-Weinert, Corey W; Yan, Ping; Paulovich, Amanda G

    2016-05-01

    In response to replication stress, a phospho-signaling cascade is activated and required for coordination of DNA repair and replication of damaged templates (intra-S-phase checkpoint) . How phospho-signaling coordinates the DNA replication stress response is largely unknown. We employed state-of-the-art liquid chromatography tandem-mass spectrometry (LC-MS/MS) approaches to generate high-coverage and quantitative proteomic and phospho-proteomic profiles during replication stress in yeast, induced by continuous exposure to the DNA alkylating agent methyl methanesulfonate (MMS) . We identified 32,057 unique peptides representing the products of 4296 genes and 22,061 unique phosphopeptides representing the products of 3183 genes. A total of 542 phosphopeptides (mapping to 339 genes) demonstrated an abundance change of greater than or equal to twofold in response to MMS. The screen enabled detection of nearly all of the proteins known to be involved in the DNA damage response, as well as many novel MMS-induced phosphorylations. We assessed the functional importance of a subset of key phosphosites by engineering a panel of phosphosite mutants in which an amino acid substitution prevents phosphorylation. In total, we successfully mutated 15 MMS-responsive phosphorylation sites in seven representative genes including APN1 (base excision repair); CTF4 and TOF1 (checkpoint and sister-chromatid cohesion); MPH1 (resolution of homologous recombination intermediates); RAD50 and XRS2 (MRX complex); and RAD18 (PRR). All of these phosphorylation site mutants exhibited MMS sensitivity, indicating an important role in protecting cells from DNA damage. In particular, we identified MMS-induced phosphorylation sites on Xrs2 that are required for MMS resistance in the absence of the MRX activator, Sae2, and that affect telomere maintenance.

  18. DNA Replication Stress Phosphoproteome Profiles Reveal Novel Functional Phosphorylation Sites on Xrs2 in Saccharomyces cerevisiae.

    PubMed

    Huang, Dongqing; Piening, Brian D; Kennedy, Jacob J; Lin, Chenwei; Jones-Weinert, Corey W; Yan, Ping; Paulovich, Amanda G

    2016-05-01

    In response to replication stress, a phospho-signaling cascade is activated and required for coordination of DNA repair and replication of damaged templates (intra-S-phase checkpoint) . How phospho-signaling coordinates the DNA replication stress response is largely unknown. We employed state-of-the-art liquid chromatography tandem-mass spectrometry (LC-MS/MS) approaches to generate high-coverage and quantitative proteomic and phospho-proteomic profiles during replication stress in yeast, induced by continuous exposure to the DNA alkylating agent methyl methanesulfonate (MMS) . We identified 32,057 unique peptides representing the products of 4296 genes and 22,061 unique phosphopeptides representing the products of 3183 genes. A total of 542 phosphopeptides (mapping to 339 genes) demonstrated an abundance change of greater than or equal to twofold in response to MMS. The screen enabled detection of nearly all of the proteins known to be involved in the DNA damage response, as well as many novel MMS-induced phosphorylations. We assessed the functional importance of a subset of key phosphosites by engineering a panel of phosphosite mutants in which an amino acid substitution prevents phosphorylation. In total, we successfully mutated 15 MMS-responsive phosphorylation sites in seven representative genes including APN1 (base excision repair); CTF4 and TOF1 (checkpoint and sister-chromatid cohesion); MPH1 (resolution of homologous recombination intermediates); RAD50 and XRS2 (MRX complex); and RAD18 (PRR). All of these phosphorylation site mutants exhibited MMS sensitivity, indicating an important role in protecting cells from DNA damage. In particular, we identified MMS-induced phosphorylation sites on Xrs2 that are required for MMS resistance in the absence of the MRX activator, Sae2, and that affect telomere maintenance. PMID:27017623

  19. Delineation of WRN Helicase Function with EXO1 in the Replicational Stress Response

    PubMed Central

    Aggarwal, Monika; Sommers, Joshua A.; Morris, Christa; Brosh, Robert M.

    2010-01-01

    The WRN gene defective in the premature aging disorder Werner syndrome encodes a helicase/exonuclease. We examined the ability of WRN to rescue DNA damage sensitivity of a yeast mutant defective in the Rad50 subunit of Mre11-Rad50- Xrs2 nuclease complex implicated in homologous recombination repair. Genetic studies revealed WRN operates in a yEXO1-dependent pathway to rescue rad50 sensitivity to methylmethane sulfonate (MMS) and prevent mitotic catastrophe. WRN helicase, but not exonuclease, is required for MMS resistance. WRN missense mutations in helicase or RecQ C-terminal domains interfered with the ability of WRN to rescue rad50 MMS sensitivity. WRN does not rescue rad50 ionizing radiation (IR) sensitivity, suggesting that WRN, in collaboration with yEXO1, is tailored to relieve replicational stress imposed by alkylated base damage. WRN and yEXO1 are associated with each other in vivo. Purified WRN stimulates hEXO1 nuclease activity on DNA substrates associated with a stalled or regressed replication fork. We propose WRN helicase operates in an EXO1-dependent pathway to help cells survive replicational stress. In contrast to WRN, BLM helicase defective in Bloom’s syndrome failed to rescue rad50 MMS sensitivity, but partially restored IR resistance, suggesting a delineation of function by the human RecQ helicases. PMID:20447876

  20. Spongionella secondary metabolites protect mitochondrial function in cortical neurons against oxidative stress.

    PubMed

    Leirós, Marta; Sánchez, Jon A; Alonso, Eva; Rateb, Mostafa E; Houssen, Wael E; Ebel, Rainer; Jaspars, Marcel; Alfonso, Amparo; Botana, Luis M

    2014-02-01

    The marine habitat provides a large number of structurally-diverse bioactive compounds for drug development. Marine sponges have been studied over many years and are found to be a rich source of these bioactive chemicals. This study is focused on the evaluation of the activity of six diterpene derivatives isolated from Spongionella sp. on mitochondrial function using an oxidative in vitro stress model. The test compounds include the Gracilins (A, H, K, J and L) and tetrahydroaplysulphurin-1. Compounds were co-incubated with hydrogen peroxide for 12 hours to determine their protective capacities and their effect on markers of apoptosis and Nrf2/ARE pathways was evaluated. Results conclude that Gracilins preserve neurons against oxidative damage, and that in particular, tetrahydroaplysulphurin-1 shows a complete neuroprotective activity. Oxidative stress is linked to mitochondrial dysfunction and consequently to neurodegenerative disorders like Parkinson and Alzheimer diseases, Friedreich ataxia or Amyotrophic lateral sclerosis. This neuroprotection against oxidation conditions suggest that these metabolites could be interesting lead candidates in drug development for neurodegenerative diseases. PMID:24473170

  1. Perivascular Mast Cells Govern Shear Stress-Induced Arteriogenesis by Orchestrating Leukocyte Function.

    PubMed

    Chillo, Omary; Kleinert, Eike Christian; Lautz, Thomas; Lasch, Manuel; Pagel, Judith-Irina; Heun, Yvonn; Troidl, Kerstin; Fischer, Silvia; Caballero-Martinez, Amelia; Mauer, Annika; Kurz, Angela R M; Assmann, Gerald; Rehberg, Markus; Kanse, Sandip M; Nieswandt, Bernhard; Walzog, Barbara; Reichel, Christoph A; Mannell, Hanna; Preissner, Klaus T; Deindl, Elisabeth

    2016-08-23

    The body has the capacity to compensate for an occluded artery by creating a natural bypass upon increased fluid shear stress. How this mechanical force is translated into collateral artery growth (arteriogenesis) is unresolved. We show that extravasation of neutrophils mediated by the platelet receptor GPIbα and uPA results in Nox2-derived reactive oxygen radicals, which activate perivascular mast cells. These c-kit(+)/CXCR-4(+) cells stimulate arteriogenesis by recruiting additional neutrophils as well as growth-promoting monocytes and T cells. Additionally, mast cells may directly contribute to vascular remodeling and vascular cell proliferation through increased MMP activity and by supplying growth-promoting factors. Boosting mast cell recruitment and activation effectively promotes arteriogenesis, thereby protecting tissue from severe ischemic damage. We thus find that perivascular mast cells are central regulators of shear stress-induced arteriogenesis by orchestrating leukocyte function and growth factor/cytokine release, thus providing a therapeutic target for treatment of vascular occlusive diseases.

  2. Inhibition of autophagy, lysosome and VCP function impairs stress granule assembly

    PubMed Central

    Seguin, S J; Morelli, F F; Vinet, J; Amore, D; De Biasi, S; Poletti, A; Rubinsztein, D C; Carra, S

    2014-01-01

    Stress granules (SGs) are mRNA-protein aggregates induced during stress, which accumulate in many neurodegenerative diseases. Previously, the autophagy-lysosome pathway and valosin-containing protein (VCP), key players of the protein quality control (PQC), were shown to regulate SG degradation. This is consistent with the idea that PQC may survey and/or assist SG dynamics. However, despite these observations, it is currently unknown whether the PQC actively participates in SG assembly. Here, we describe that inhibition of autophagy, lysosomes and VCP causes defective SG formation after induction. Silencing the VCP co-factors UFD1L and PLAA, which degrade defective ribosomal products (DRIPs) and 60S ribosomes, also impaired SG assembly. Intriguingly, DRIPs and 60S, which are released from disassembling polysomes and are normally excluded from SGs, were significantly retained within SGs in cells with impaired autophagy, lysosome or VCP function. Our results suggest that deregulated autophagy, lysosomal or VCP activities, which occur in several neurodegenerative (VCP-associated) diseases, may alter SG morphology and composition. PMID:25034784

  3. Relationship of radionuclide indexes of cardiac function during interventions: volume loading, afterload stress, exercise, and pacing

    SciTech Connect

    Slutsky, R.A.

    1983-04-01

    We compared three radionuclide index of cardiac function: 1) the ejection fraction (EF), 2) the mean ejection rate (ER), and 3) the mean velocity of circumferential fiber shortening (MVCF) during volume loading, phenylephrine hydrochloride stress, exercise, and atrial pacing. All behaved in a similar (linear) fashion, allowing appropriate hemodynamic conclusions to be drawn using either index. During atrial pacing, the ejection fraction declined when velocity indexes increased, suggesting that the ejection fraction may not be a suitable index to characterize alterations in inotropic state during rapid alterations in heart rate, particular in the absence of angina pectoris. This may result from the reductions in cardiac volume for the duration of pacing, where the velocity index is preserved. In most circumstances excluding atrial pacing, ejection fraction during interventions is an adequate index of the change of myocardial contractile state. Overall, radionuclide angiography is an excellent technique to characterize acute hemodynamic interventions, with ejection fraction, in general, the simplest and most reliable of cardiac indexes during stress interventions.

  4. Perivascular Mast Cells Govern Shear Stress-Induced Arteriogenesis by Orchestrating Leukocyte Function.

    PubMed

    Chillo, Omary; Kleinert, Eike Christian; Lautz, Thomas; Lasch, Manuel; Pagel, Judith-Irina; Heun, Yvonn; Troidl, Kerstin; Fischer, Silvia; Caballero-Martinez, Amelia; Mauer, Annika; Kurz, Angela R M; Assmann, Gerald; Rehberg, Markus; Kanse, Sandip M; Nieswandt, Bernhard; Walzog, Barbara; Reichel, Christoph A; Mannell, Hanna; Preissner, Klaus T; Deindl, Elisabeth

    2016-08-23

    The body has the capacity to compensate for an occluded artery by creating a natural bypass upon increased fluid shear stress. How this mechanical force is translated into collateral artery growth (arteriogenesis) is unresolved. We show that extravasation of neutrophils mediated by the platelet receptor GPIbα and uPA results in Nox2-derived reactive oxygen radicals, which activate perivascular mast cells. These c-kit(+)/CXCR-4(+) cells stimulate arteriogenesis by recruiting additional neutrophils as well as growth-promoting monocytes and T cells. Additionally, mast cells may directly contribute to vascular remodeling and vascular cell proliferation through increased MMP activity and by supplying growth-promoting factors. Boosting mast cell recruitment and activation effectively promotes arteriogenesis, thereby protecting tissue from severe ischemic damage. We thus find that perivascular mast cells are central regulators of shear stress-induced arteriogenesis by orchestrating leukocyte function and growth factor/cytokine release, thus providing a therapeutic target for treatment of vascular occlusive diseases. PMID:27524614

  5. Plant phospholipases D and C and their diverse functions in stress responses.

    PubMed

    Hong, Yueyun; Zhao, Jian; Guo, Liang; Kim, Sang-Chul; Deng, Xianjun; Wang, Geliang; Zhang, Gaoyang; Li, Maoyin; Wang, Xuemin

    2016-04-01

    Phospholipases D (PLD) and C (PLC) hydrolyze the phosphodiesteric linkages of the head group of membrane phospholipids. PLDs and PLCs in plants occur in different forms: the calcium-dependent phospholipid binding domain-containing PLDs (C2-PLDs), the plekstrin homology and phox homology domain-containing PLDs (PX/PH-PLDs), phosphoinositide-specific PLC (PI-PLC), and non-specific PLC (NPC). They differ in structures, substrate selectivities, cofactor requirements, and/or reaction conditions. These enzymes and their reaction products, such as phosphatidic acid (PA), diacylglycerol (DAG), and inositol polyphosphates, play important, multifaceted roles in plant response to abiotic and biotic stresses. Here, we review biochemical properties, cellular effects, and physiological functions of PLDs and PLCs, particularly in the context of their roles in stress response along with advances made on the role of PA and DAG in cell signaling in plants. The mechanism of actions, including those common and distinguishable among different PLDs and PLCs, will also be discussed. PMID:26783886

  6. Genetic Differences in the Immediate Transcriptome Response to Stress Predict Risk-Related Brain Function and Psychiatric Disorders.

    PubMed

    Arloth, Janine; Bogdan, Ryan; Weber, Peter; Frishman, Goar; Menke, Andreas; Wagner, Klaus V; Balsevich, Georgia; Schmidt, Mathias V; Karbalai, Nazanin; Czamara, Darina; Altmann, Andre; Trümbach, Dietrich; Wurst, Wolfgang; Mehta, Divya; Uhr, Manfred; Klengel, Torsten; Erhardt, Angelika; Carey, Caitlin E; Conley, Emily Drabant; Ruepp, Andreas; Müller-Myhsok, Bertram; Hariri, Ahmad R; Binder, Elisabeth B

    2015-06-01

    Depression risk is exacerbated by genetic factors and stress exposure; however, the biological mechanisms through which these factors interact to confer depression risk are poorly understood. One putative biological mechanism implicates variability in the ability of cortisol, released in response to stress, to trigger a cascade of adaptive genomic and non-genomic processes through glucocorticoid receptor (GR) activation. Here, we demonstrate that common genetic variants in long-range enhancer elements modulate the immediate transcriptional response to GR activation in human blood cells. These functional genetic variants increase risk for depression and co-heritable psychiatric disorders. Moreover, these risk variants are associated with inappropriate amygdala reactivity, a transdiagnostic psychiatric endophenotype and an important stress hormone response trigger. Network modeling and animal experiments suggest that these genetic differences in GR-induced transcriptional activation may mediate the risk for depression and other psychiatric disorders by altering a network of functionally related stress-sensitive genes in blood and brain. PMID:26050039

  7. Functional activation and neural networks in women with posttraumatic stress disorder related to intimate partner violence

    PubMed Central

    Simmons, Alan; Paulus, Martin P.; Thorp, Steven R.; Matthews, Scott C.; Norman, Sonya B.; Stein, Murray B.

    2008-01-01

    Background Intimate partner violence (IPV) is one of the most common causes of posttraumatic stress disorder (PTSD) in women. Victims of IPV are often preoccupied by the anticipation of impending harm. This investigation tested the hypothesis that IPV-related PTSD individuals show exaggerated insula reactivity to the anticipation of aversive stimuli. Methods Fifteen women with a history of IPV and consequent PTSD (IPV-PTSD) and 15 non-traumatized control (NTC) women performed a task involving cued anticipation to images of positive and negative events during functional magnetic resonance imaging. Results Both groups showed increased activation of bilateral anterior insula during anticipation of negative images minus anticipation of positive images. Activation in right anterior/middle insula was significantly greater in the IPV-PTSD relative to the NTC group. Functional connectivity analysis revealed that changes in activation in right middle insula and bilateral anterior insula were more strongly associated with amygdala activation changes in NTC than in IPV-PTSD subjects. Conclusions Increased activation in the anterior/middle insula during negative anticipation in women with IPV-related PTSD. These findings in women with IPV could be a consequence of the IPV exposure, reflect pre-existing differences in insular function, or due to the development of PTSD. Thus, future longitudinal studi4s need to examine these possibilities. PMID:18639236

  8. Abnormal functional architecture of amygdala-centered networks in adolescent posttraumatic stress disorder.

    PubMed

    Aghajani, Moji; Veer, Ilya M; van Hoof, Marie-José; Rombouts, Serge A R B; van der Wee, Nic J; Vermeiren, Robert R J M

    2016-03-01

    Posttraumatic stress disorder (PTSD) is a prevalent, debilitating, and difficult to treat psychiatric disorder. Very little is known of how PTSD affects neuroplasticity in the developing adolescent brain. Whereas multiple lines of research implicate amygdala-centered network dysfunction in the pathophysiology of adult PTSD, no study has yet examined the functional architecture of amygdala subregional networks in adolescent PTSD. Using intrinsic functional connectivity analysis, we investigated functional connectivity of the basolateral (BLA) and centromedial (CMA) amygdala in 19 sexually abused adolescents with PTSD relative to 23 matched controls. Additionally, we examined whether altered amygdala subregional connectivity coincides with abnormal grey matter volume of the amygdaloid complex. Our analysis revealed abnormal amygdalar connectivity and morphology in adolescent PTSD patients. More specifically, PTSD patients showed diminished right BLA connectivity with a cluster including dorsal and ventral portions of the anterior cingulate and medial prefrontal cortices (p < 0.05, corrected). In contrast, PTSD patients showed increased left CMA connectivity with a cluster including the orbitofrontal and subcallosal cortices (p < 0.05, corrected). Critically, these connectivity changes coincided with diminished grey matter volume within BLA and CMA subnuclei (p < 0.05, corrected), with CMA connectivity shifts additionally relating to more severe symptoms of PTSD. These findings provide unique insights into how perturbations in major amygdalar circuits could hamper fear regulation and drive excessive acquisition and expression of fear in PTSD. As such, they represent an important step toward characterizing the neurocircuitry of adolescent PTSD, thereby informing the development of reliable biomarkers and potential therapeutic targets.

  9. NFAT5 in cellular adaptation to hypertonic stress - regulations and functional significance.

    PubMed

    Cheung, Chris Yk; Ko, Ben Cb

    2013-01-01

    The Nuclear Factor of Activated T Cells-5 (NFAT5), also known as OREBP or TonEBP, is a member of the nuclear factors of the activated T cells family of transcription factors. It is also the only known tonicity-regulated transcription factor in mammals. NFAT5 was initially known for its role in the hypertonic kidney inner medulla for orchestrating a genetic program to restore the cellular homeostasis. Emerging evidence, however, suggests that NFAT5 might play a more diverse functional role, including a pivotal role in blood pressure regulation and the development of autoimmune diseases. Despite the growing significance of NFAT5 in physiology and diseases, our understanding of how its activity is regulated remains very limited. Furthermore, how changes in tonicities are converted into functional outputs via NFAT5 remains elusive. Therefore, this review aims to summarize our current knowledge on the functional roles of NFAT5 in osmotic stress adaptation and the signaling pathways that regulate its activity. PMID:23618372

  10. Differential Contributions of Nonmuscle Myosin II Isoforms and Functional Domains to Stress Fiber Mechanics.

    PubMed

    Chang, Ching-Wei; Kumar, Sanjay

    2015-09-04

    While is widely acknowledged that nonmuscle myosin II (NMMII) enables stress fibers (SFs) to generate traction forces against the extracellular matrix, little is known about how specific NMMII isoforms and functional domains contribute to SF mechanics. Here we combine biophotonic and genetic approaches to address these open questions. First, we suppress the NMMII isoforms MIIA and MIIB and apply femtosecond laser nanosurgery to ablate and investigate the viscoelastic retraction of individual SFs. SF retraction dynamics associated with MIIA and MIIB suppression qualitatively phenocopy our earlier measurements in the setting of Rho kinase (ROCK) and myosin light chain kinase (MLCK) inhibition, respectively. Furthermore, fluorescence imaging and photobleaching recovery reveal that MIIA and MIIB are enriched in and more stably localize to ROCK- and MLCK-controlled central and peripheral SFs, respectively. Additional domain-mapping studies surprisingly reveal that deletion of the head domain speeds SF retraction, which we ascribe to reduced drag from actomyosin crosslinking and frictional losses. We propose a model in which ROCK/MIIA and MLCK/MIIB functionally regulate common pools of SFs, with MIIA crosslinking and motor functions jointly contributing to SF retraction dynamics and cellular traction forces.

  11. Altered resting-state functional activity in posttraumatic stress disorder: A quantitative meta-analysis

    PubMed Central

    Wang, Ting; Liu, Jia; Zhang, Junran; Zhan, Wang; Li, Lei; Wu, Min; Huang, Hua; Zhu, Hongyan; Kemp, Graham J.; Gong, Qiyong

    2016-01-01

    Many functional neuroimaging studies have reported differential patterns of spontaneous brain activity in posttraumatic stress disorder (PTSD), but the findings are inconsistent and have not so far been quantitatively reviewed. The present study set out to determine consistent, specific regional brain activity alterations in PTSD, using the Effect Size Signed Differential Mapping technique to conduct a quantitative meta-analysis of resting-state functional neuroimaging studies of PTSD that used either a non-trauma (NTC) or a trauma-exposed (TEC) comparison control group. Fifteen functional neuroimaging studies were included, comparing 286 PTSDs, 203 TECs and 155 NTCs. Compared with NTC, PTSD patients showed hyperactivity in the right anterior insula and bilateral cerebellum, and hypoactivity in the dorsal medial prefrontal cortex (mPFC); compared with TEC, PTSD showed hyperactivity in the ventral mPFC. The pooled meta-analysis showed hypoactivity in the posterior insula, superior temporal, and Heschl’s gyrus in PTSD. Additionally, subgroup meta-analysis (non-medicated subjects vs. NTC) identified abnormal activation in the prefrontal-limbic system. In meta-regression analyses, mean illness duration was positively associated with activity in the right cerebellum (PTSD vs. NTC), and illness severity was negatively associated with activity in the right lingual gyrus (PTSD vs. TEC). PMID:27251865

  12. Assessing impact of differential symptom functioning on post-traumatic stress disorder (PTSD) diagnosis.

    PubMed

    He, Qiwei; Glas, Cees A W; Veldkamp, Bernard P

    2014-06-01

    This article explores the generalizability of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnostic criteria for post-traumatic stress disorder (PTSD) to various subpopulations. Besides identifying the differential symptom functioning (also referred to as differential item functioning [DIF]) related to various background variables such as gender, marital status and educational level, this study emphasizes the importance of evaluating the impact of DIF on population inferences as made in health surveys and clinical trials, and on the diagnosis of individual patients. Using a sample from the National Comorbidity Study-Replication (NCS-R), four symptoms for gender, one symptom for marital status, and three symptoms for educational level were significantly flagged as DIF, but their impact on diagnosis was fairly small. We conclude that the DSM-IV diagnostic criteria for PTSD do not produce substantially biased results in the investigated subpopulations, and there should be few reservations regarding their use. Further, although the impact of DIF (i.e. the influence of differential symptom functioning on diagnostic results) was found to be quite small in the current study, we recommend that diagnosticians always perform a DIF analysis of various subpopulations using the methodology presented here to ensure the diagnostic criteria is valid in their own studies.

  13. Functions of health fatalism: fatalistic talk as face saving, uncertainty management, stress relief and sense making.

    PubMed

    Keeley, Bethany; Wright, Lanelle; Condit, Celeste M

    2009-07-01

    Much research on fatalism assumes that fatalistic statements represent a global outlook that conflicts with belief in the efficacy of health behaviours. Other scholars have suggested a more contextual approach, suggesting that fatalism fulfils personal and social functions. This study analyses 96 in-depth lay interviews in the US, most with low-income members of the general public, about four diseases: heart disease, lung cancer, diabetes and depression. Within these interviews, fatalistic statements always occurred alongside statements endorsing the utility of behaviours for protecting health. This usage pattern suggests that these statements may have useful functions, rather than being simply a repudiation of the utility of health choices. We examine four functions that are suggested by previous researchers or by the participants' comments: stress relief, uncertainty management, sense making and (less strongly) face saving. As these themes indicate, individuals often make fatalistic statements to express an understanding of locally or broadly limiting factors for health efficacy, including genes, spiritual agents, prior behaviours, personality, and other factors.

  14. Perfusion deficits and functional connectivity alterations in patients with post-traumatic stress disorder

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Li, Baojuan; Zhang, Xi; Zhang, Linchuan; Li, Liang; Lu, Hongbing

    2016-03-01

    To explore the alteration in cerebral blood flow (CBF) and functional connectivity between survivors with recent onset post-traumatic stress disorder (PTSD) and without PTSD, survived from the same coal mine flood disaster. In this study, a processing pipeline using arterial spin labeling (ASL) sequence was proposed. Considering low spatial resolution of ASL sequence, a linear regression method was firstly used to correct the partial volume (PV) effect for better CBF estimation. Then the alterations of CBF between two groups were analyzed using both uncorrected and PV-corrected CBF maps. Based on altered CBF regions detected from the CBF analysis as seed regions, the functional connectivity abnormities in PTSD patients was investigated. The CBF analysis using PV-corrected maps indicates CBF deficits in the bilateral frontal lobe, right superior frontal gyrus and right corpus callosum of PTSD patients, while only right corpus callosum was identified in uncorrected CBF analysis. Furthermore, the regional CBF of the right superior frontal gyrus exhibits significantly negative correlation with the symptom severity in PTSD patients. The resting-state functional connectivity indicates increased connectivity between left frontal lobe and right parietal lobe. These results indicate that PV-corrected CBF exhibits more subtle perfusion changes and may benefit further perfusion and connectivity analysis. The symptom-specific perfusion deficits and aberrant connectivity in above memory-related regions may be putative biomarkers for recent onset PTSD induced by a single prolonged trauma exposure and help predict the severity of PTSD.

  15. Hsp72 chaperone function is dispensable for protection against stress-induced apoptosis.

    PubMed

    Chow, Ari M; Steel, Rohan; Anderson, Robin L

    2009-05-01

    In addition to its role as a molecular chaperone, heat shock protein 72 (Hsp72) protects cells against a wide range of apoptosis inducing stresses. However, it is unclear if these two roles are functionally related or whether Hsp72 inhibits apoptosis by a mechanism independent of chaperone activity. The N-terminal adenosine triphosphatase domain, substrate-binding domain and the C-terminal EEVD regulatory motif of Hsp72 are all essential for chaperone activity. In this study, we show that Hsp72 mutants with a functional substrate-binding domain but lacking chaperone activity retain their ability to protect cells against apoptosis induced by heat and tumor necrosis factor alpha. In contrast, a deletion mutant lacking a functional substrate-binding domain has no protective capacity. The ability of the Hsp72 substrate-binding domain to inhibit apoptosis independent of the regulatory effects of the adenosine triphosphate-binding domain indicates that the inhibition of apoptosis may involve a stable binding interaction with a regulatory substrate rather than Hsp72 chaperone activity. PMID:18819021

  16. Attributing functions to ectomycorrhizal fungal identities in assemblages for nitrogen acquisition under stress

    PubMed Central

    Pena, Rodica; Polle, Andrea

    2014-01-01

    Mycorrhizal fungi have a key role in nitrogen (N) cycling, particularly in boreal and temperate ecosystems. However, the significance of ectomycorrhizal fungal (EMF) diversity for this important ecosystem function is unknown. Here, EMF taxon-specific N uptake was analyzed via 15N isotope enrichment in complex root-associated assemblages and non-mycorrhizal root tips in controlled experiments. Specific 15N enrichment in ectomycorrhizas, which represents the N influx and export, as well as the exchange of 15N with the N pool of the root tip, was dependent on the fungal identity. Light or water deprivation revealed interspecific response diversity for N uptake. Partial taxon-specific N fluxes for ectomycorrhizas were assessed, and the benefits of EMF assemblages for plant N nutrition were estimated. We demonstrated that ectomycorrhizal assemblages provide advantages for inorganic N uptake compared with non-mycorrhizal roots under environmental constraints but not for unstressed plants. These benefits were realized via stress activation of distinct EMF taxa, which suggests significant functional diversity within EMF assemblages. We developed and validated a model that predicts net N flux into the plant based on taxon-specific 15N enrichment in ectomycorrhizal root tips. These results open a new avenue to characterize the functional traits of EMF taxa in complex communities. PMID:24030593

  17. Viewing nature scenes positively affects recovery of autonomic function following acute-mental stress.

    PubMed

    Brown, Daniel K; Barton, Jo L; Gladwell, Valerie F

    2013-06-01

    A randomized crossover study explored whether viewing different scenes prior to a stressor altered autonomic function during the recovery from the stressor. The two scenes were (a) nature (composed of trees, grass, fields) or (b) built (composed of man-made, urban scenes lacking natural characteristics) environments. Autonomic function was assessed using noninvasive techniques of heart rate variability; in particular, time domain analyses evaluated parasympathetic activity, using root-mean-square of successive differences (RMSSD). During stress, secondary cardiovascular markers (heart rate, systolic and diastolic blood pressure) showed significant increases from baseline which did not differ between the two viewing conditions. Parasympathetic activity, however, was significantly higher in recovery following the stressor in the viewing scenes of nature condition compared to viewing scenes depicting built environments (RMSSD; 50.0 ± 31.3 vs 34.8 ± 14.8 ms). Thus, viewing nature scenes prior to a stressor alters autonomic activity in the recovery period. The secondary aim was to examine autonomic function during viewing of the two scenes. Standard deviation of R-R intervals (SDRR), as change from baseline, during the first 5 min of viewing nature scenes was greater than during built scenes. Overall, this suggests that nature can elicit improvements in the recovery process following a stressor.

  18. An event-related potentials study on the attention function of posttraumatic stress disorder

    PubMed Central

    Cui, Hong; Liu, Xiaohui; Chen, Guoliang; Shan, Moshui; Jia, Yanyan

    2015-01-01

    Objective: In order to examine the functional defects and attentional bias in post-traumatic stress disorder (PTSD) patients, event-related potentials (ERP) of attention was investigated. Methods: Three groups of emotion pictures, positive, negative (or violent) and neutral, were viewed by 19 PTSD patients and 15 normal controls. Each picture had a frame, and participants reacted to the color of the frame by clicking buttons. Electroencephalogram (EEG) and behavior data were recorded. Peak latencies and amplitudes of P2 were measured. Results: For the three groups of pictures, PTSD patients had longer reaction time than the controls. Significant difference was found between PTSD patients and controls in response to violent, positive and neutral pictures. PMID:26379882

  19. Probing Reward Function in Posttraumatic Stress Disorder: Expectancy and Satisfaction with Monetary Gains and Losses

    PubMed Central

    Hopper, James W.; Pitman, Roger K.; Su, Zhaohui; Heyman, Gene M.; Lasko, Natasha B.; Macklin, Michael L.; Orr, Scott P.; Lukas, Scott E.; Elman, Igor

    2008-01-01

    Background Post-traumatic stress disorder (PTSD) may be associated with dysfunctional reward processing. The present study assessed for such dysfunction in both the expectancy and outcome phases of reward processing. Methods Male Vietnam veterans with (n=15) and without (n=11) combat-related PTSD were administered a wheel of fortune-type gambling task. Self-reported ratings of expectancy and satisfaction were collected respectively before and after each experience of monetary gain or loss. Results PTSD participants reported both lower expectancy of reward and lower satisfaction with reward when it was received. The latter result was manifest in a failure of PTSD participants to show the greater satisfaction that normally accompanies rewards received under conditions of low expectancy. Conclusion These results suggest reward function impairment in PTSD related to expectancy, satisfaction, and the expectancy-satisfaction relationship. PMID:18068725

  20. Numerical Analysis of Stress Intensity Factors in Three-Dimensional Functionally Graded Materials

    SciTech Connect

    Guo Licheng; Wu Linzhi; Yu Hongjun

    2008-02-15

    In this paper, a finite element method based on nonhomogeneous elements is used to study crack problems in three-dimensional (3D) functionally graded materials (FGMs). Since the actual material properties at each integral point are employed in the integration during formation of the element stiffness matrix, each element can have nonhomogeneous material properties. By this method, the number of elements is reduced and the meshing effort for the structure is simplified. Therefore, the modeling process for numerical simulation of fracture behavior in 3D FGMs is greatly simplified. The crack front characteristics of Mode-I edge penetrable crack in 3D FGM specimens are studied under uniform tension loading. The influence of material nonhomogeneity constant and geometric parameters on the stress intensity factors (SIFs) of the 3D FGM specimens are investigated.

  1. Isohydric and anisohydric strategies of wheat genotypes under osmotic stress: biosynthesis and function of ABA in stress responses.

    PubMed

    Gallé, Ágnes; Csiszár, Jolán; Benyó, Dániel; Laskay, Gábor; Leviczky, Tünde; Erdei, László; Tari, Irma

    2013-11-01

    Changes in water potential (ψw), stomatal conductance, abscisic acid (ABA) accumulation, expression of the major genes involved in ABA biosynthesis, activities of abscisic aldehyde oxidase (AO, EC 1.2.3.1) and antioxidant enzymes were studied in two wheat cultivars with contrasting acclimation strategies subjected to medium strength osmotic stress (-0.976MPa) induced by polyethylene glycol (PEG 6000). Because the biosynthetic pathway of ABA involves multiple gene products, the aim of this study was to unravel how these genes are regulated in isohydric and anisohydric wheat genotypes. In the root tissues of the isohydric cultivar, Triticum aestivum cv. Kobomugi, osmotic stress increased the transcript levels of 9-cis-epoxycarotenoid dioxygenase (NCED) gene, controlling the rate limiting step of ABA biosynthesis. Moreover, this cultivar exhibited a higher basal activity and a higher induction of aldehyde oxidase isoenzymes (AAO2-AAO3), responsible for converting ABAldehyde to ABA. It was found that the fast activation of the ABA biosynthesis in the roots generated an enhanced ABA pool in the shoot, which brought about a faster closure of the stomata upon increasing osmotic stress and, as a result, the plants could maintain ψw in the tissues close to the control level. In contrast, the anisohydric genotype, cv. GK Öthalom, exhibited a moderate induction of ABA biosynthesis in the roots, leading to the maintenance but no increase in the concentration of ABA on the basis of tissue water content in the leaves. Due to the slower response of their stomata to water deficit, the tissues of cv. GK Öthalom have to acclimate to much more negative water potentials during increasing osmotic stress. A decreased activity of superoxide dismutase (SOD) was found in the leaves and roots of both cultivars exposed to osmotic stress, but in the roots elevated activities of catalase (CAT), peroxidase (POX), glutathione reductase (GR) and glutathione transferase (GST) were detected in

  2. Effect of late-gestation maternal heat stress on growth and immune function of dairy calves.

    PubMed

    Tao, S; Monteiro, A P A; Thompson, I M; Hayen, M J; Dahl, G E

    2012-12-01

    Heat stress during the dry period affects the cow's mammary gland development, metabolism, and immunity during the transition period. However, the effect of late-gestation heat stress on calf performance and immune status is unknown. Our objective was to evaluate the effect of heat stress during the final ~45 d of gestation on growth and immune function of calves. Calves (17/treatment) were born to cows that were exposed to cooling (CL) or heat stress (HT) during the dry period. Only heifer calves (CL, n=12; HT, n=9) were used in measurements of growth and immune status after birth. Heifer calves were managed under identical conditions. All were fed 3.78 L of colostrum from their respective dams within 4 h of birth and were weaned at 2 mo of age (MOA). Body weight (BW) was obtained at weaning and then monthly until 7 MOA. Withers height (WH) was measured monthly from 3 to 7 MOA. Hematocrit and plasma total protein were assessed at birth, 1, 4, 7, 11, 14, 18, 21, 25, and 28 d of age. Total serum IgG was evaluated at 1, 4, 7, 11, 14, 18, 21, 25, and 28 d of age, and apparent efficiency of absorption was calculated. Peripheral blood mononuclear cells were isolated at 7, 28, 42, and 56 d of age, and proliferation rate was measured by (3)H-thymidine incorporation in vitro. Blood cortisol concentration was measured in the dams during the dry period and in calves in the preweaning period. Gestation length was 4d shorter for HT cows compared with CL cows. Calves from CL cows had greater BW than calves from HT cows at birth (42.5 vs. 36.5 kg). Compared with CL heifers, HT heifers had decreased weaning BW (78.5 vs. 65.9 kg) but similar BW (154.6 vs. 146.4 kg) and WH (104.8 vs. 103.4 cm) from 3 to 7 MOA. Compared with CL, heifers from HT cows had less total plasma protein (6.3 vs. 5.9 g/dL), total serum IgG (1,577.3 vs. 1,057.8 mg/dL), and apparent efficiency of absorption (33.6 vs. 19.2%), and tended to have decreased hematocrit (33 vs. 30%). Additionally, CL heifers had

  3. Diauxic shift-induced stress resistance against hydroperoxides in Saccharomyces cerevisiae is not an adaptive stress response and does not depend on functional mitochondria.

    PubMed

    Maris, A F; Assumpção, A L; Bonatto, D; Brendel, M; Henriques, J A

    2001-05-01

    Respiring Saccharomyces cerevisiae cells grown on a non-fermentable carbon source are intrinsically more resistant to several stresses, including oxidative stress. The mechanisms leading to increased stress resistance are not yet well understood. Active mitochondria are the major source of intracellular reactive oxygen species (ROS), which could cause the up-regulation of the antioxidant defense systems. We investigated the role of mitochondria in the intrinsic stress resistance against the hydroperoxides H2O2 and tert-butylhydroperoxide 4 h after a shift in carbon source. We found that, independently of functional mitochondria, the yeast acquired the intrinsic resistance of respiring cells against hydroperoxides solely as a response to a change of carbon source in the growth medium. Furthermore, utilizing reporter gene fusion constructs, we monitored the expression of the gamma-glutamylcysteinyl synthetase (encoded by GSH1) and the two superoxide dismutases (encoded by SOD1 and SOD2) during the metabolic transition from fermentation to respiration; and we detected an up-regulation of all three genes during the diauxic shift. Overall available data allowed us to propose that the antioxidant system of S. cerevisiae could be considered as a class of genes under glucose/carbon catabolite regulation. This control system is different from the well-known adaptive response to oxidative stress.

  4. SIRT1 positively regulates autophagy and mitochondria function in embryonic stem cells under oxidative stress.

    PubMed

    Ou, Xuan; Lee, Man Ryul; Huang, Xinxin; Messina-Graham, Steven; Broxmeyer, Hal E

    2014-05-01

    SIRT1, an NAD-dependent deacetylase, plays a role in regulation of autophagy. SIRT1 increases mitochondrial function and reduces oxidative stress, and has been linked to age-related reactive oxygen species (ROS) generation, which is highly dependent on mitochondrial metabolism. H2O2 induces oxidative stress and autophagic cell death through interference with Beclin 1 and the mTOR signaling pathways. We evaluated connections between SIRT1 activity and induction of autophagy in murine (m) and human (h) embryonic stem cells (ESCs) upon ROS challenge. Exogenous H2 O2 (1 mM) induced apoptosis and autophagy in wild-type (WT) and Sirt1-/- mESCs. High concentrations of H2O2 (1 mM) induced more apoptosis in Sirt1-/-, than in WT mESCs. However, addition of 3-methyladenine, a widely used autophagy inhibitor, in combination with H2O2 induced more cell death in WT than in Sirt1-/- mESCs. Decreased induction of autophagy in Sirt1-/- mESCs was demonstrated by decreased conversion of LC3-I to LC3-II, lowered expression of Beclin-1, and decreased LC3 punctae and LysoTracker staining. H2O2 induced autophagy with loss of mitochondrial membrane potential and disruption of mitochondrial dynamics in Sirt1-/- mESCs. Increased phosphorylation of P70/85-S6 kinase and ribosomal S6 was noted in Sirt1-/- mESCs, suggesting that SIRT1 regulates the mTOR pathway. Consistent with effects in mESCs, inhibition of SIRT1 using Lentivirus-mediated SIRT1 shRNA in hESCs demonstrated that knockdown of SIRT1 decreased H2O2-induced autophagy. This suggests a role for SIRT1 in regulating autophagy and mitochondria function in ESCs upon oxidative stress, effects mediated at least in part by the class III PI3K/Beclin 1 and mTOR pathways.

  5. The relationship between recent stressful life events, personality traits, perceived family functioning and internet addiction among college students.

    PubMed

    Yan, Wansen; Li, Yonghui; Sui, Nan

    2014-02-01

    Internet addiction (IA) is an emerging social and mental health issue among youths. Analysis of risk factors, as well as their interactions, is crucial for understanding the development of IA. This study investigated the relationship between recent stressful life events, personality traits, perceived family functioning and IA in 892 college students. Subjects were classified into categories (non-addicted, mild IA or severe IA) using the Chen Internet Addiction Scale. Stressful life events, personality traits and family functioning were assessed using the Adolescent Self-Rating Life Events Checklist, the Eysenck Personality Questionnaire, and the Family Adaptability and Cohesion Scale, respectively. The results indicated that compared with non-addicted subjects, subjects with severe IA (9.98%) had lower family functioning, lower extraversion, higher neuroticism and psychoticism, and more stressful life events, and subjects with mild IA (11.21%) had higher neuroticism and more health and adaptation problems. Neuroticism and health and adaptation problems were potential predictors of IA. An interaction effect between psychoticism and total life stress on IA was also found. These findings highlight the role of personality traits and life stress and their interactions in college students' IA. Further research should explore the mechanisms underlying the interaction effect of psychoticism with life stress on IA.

  6. The impact of threat of shock on the framing effect and temporal discounting: executive functions unperturbed by acute stress?

    PubMed

    Robinson, Oliver J; Bond, Rebecca L; Roiser, Jonathan P

    2015-01-01

    Anxiety and stress-related disorders constitute a large global health burden, but are still poorly understood. Prior work has demonstrated clear impacts of stress upon basic cognitive function: biasing attention toward unexpected and potentially threatening information and instantiating a negative affective bias. However, the impact that these changes have on higher-order, executive, decision-making processes is unclear. In this study, we examined the impact of a translational within-subjects stress induction (threat of unpredictable shock) on two well-established executive decision-making biases: the framing effect (N = 83), and temporal discounting (N = 36). In both studies, we demonstrate (a) clear subjective effects of stress, and (b) clear executive decision-making biases but (c) no impact of stress on these decision-making biases. Indeed, Bayes factor analyses confirmed substantial preference for decision-making models that did not include stress. We posit that while stress may induce subjective mood change and alter low-level perceptual and action processes (Robinson et al., 2013c), some higher-level executive processes remain unperturbed by these impacts. As such, although stress can induce a transient affective biases and altered mood, these need not result in poor financial decision-making.

  7. The role of major depression in neurocognitive functioning in patients with posttraumatic stress disorder

    PubMed Central

    Nijdam, Mirjam J.; Gersons, Berthold P. R.; Olff, Miranda

    2013-01-01

    Background Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) frequently co-occur after traumatic experiences and share neurocognitive disturbances in verbal memory and executive functioning. However, few attempts have been made to systematically assess the role of a comorbid MDD diagnosis in neuropsychological studies in PTSD. Objective The purpose of the current study is to investigate neurocognitive deficits in PTSD patients with and without MDD. We hypothesized that PTSD patients with comorbid MDD (PTSD+MDD) would have significantly lower performance on measures of verbal memory and executive functioning than PTSD patients without MDD (PTSD–MDD). Method Participants included in this study were 140 treatment-seeking outpatients who had a diagnosis of PTSD after various single traumatic events and participated in a randomized controlled trial comparing different treatment types. Baseline neuropsychological data were compared between patients with PTSD+MDD (n=84) and patients with PTSD–MDD (n=56). Results The PTSD+MDD patients had more severe verbal memory deficits in learning and retrieving words than patients with PTSD alone. There were no differences between the groups in recall of a coherent paragraph, recognition, shifting of attention, and cognitive interference. Conclusions The results of this study suggest that a more impaired neurocognitive profile may be associated with the presence of comorbid MDD, with medium-sized group differences for verbal memory but not for executive functioning. From a clinical standpoint, being aware that certain verbal memory functions are more restricted in patients with comorbid PTSD and MDD may be relevant for treatment outcome of trauma-focused psychotherapy. PMID:23671761

  8. Early life stress elicits visceral hyperalgesia and functional reorganization of pain circuits in adult rats

    PubMed Central

    Holschneider, D.P.; Guo, Y.; Mayer, E.A.; Wang, Z.

    2015-01-01

    Early life stress (ELS) is a risk factor for developing functional gastrointestinal disorders, and has been proposed to be related to a central amplification of sensory input and resultant visceral hyperalgesia. We sought to characterize ELS-related changes in functional brain responses during acute noxious visceral stimulation. Neonatal rats (males/females) were exposed to limited bedding (ELS) or standard bedding (controls) on postnatal days 2–9. Age 10–11 weeks, animals were implanted with venous cannulas and transmitters for abdominal electromyography (EMG). Cerebral blood flow (rCBF) was mapped during colorectal distension (CRD) using [14C]-iodoantipyrine autoradiography, and analyzed in three-dimensionally reconstructed brains by statistical parametric mapping and functional connectivity. EMG responses to CRD were increased after ELS, with no evidence of a sex difference. ELS rats compared to controls showed a greater significant positive correlation of EMG with amygdalar rCBF. Factorial analysis revealed a significant main effect of ‘ELS’ on functional activation of nodes within the pain pathway (somatosensory, insular, cingulate and prefrontal cortices, locus coeruleus/lateral parabrachial n. [LC/LPB], periaqueductal gray, sensory thalamus), as well as in the amygdala, hippocampus and hypothalamus. In addition, ELS resulted in an increase in the number of significant functional connections (i.e. degree centrality) between regions within the pain circuit, including the amygdala, LC/LPB, insula, anterior ventral cingulate, posterior cingulate (retrosplenium), and stria terminalis, with decreases noted in the sensory thalamus and the hippocampus. Sex differences in rCBF were less broadly expressed, with significant differences noted at the level of the cortex, amygdala, dorsal hippocampus, raphe, sensory thalamus, and caudate-putamen. ELS showed a sexually dimorphic effect (‘Sex x ELS’ interaction) at the LC/LPB complex, globus pallidus

  9. Mitochondrial oxidative stress in aortic stiffening with age: the role of smooth muscle cell function.

    EPA Science Inventory

    OBJECTIVE: Age-related aortic stiffness is an independent risk factor for cardiovascular diseases. Although oxidative stress is implicated in aortic stiffness, the underlying molecular mechanisms remain unelucidated. Here, we examined the source of oxidative stress in aging and i...

  10. Active Hexose Correlated Compound Activates Immune Function to Decrease Chlamydia trachomatis Shedding in a Murine Stress Model

    PubMed Central

    Belay, Tesfaye; Fu, Chih-lung; Woart, Anthony

    2016-01-01

    A cold-induced stress mouse model for investigating chlamydia genital infection and immune response analysis was established in our laboratory. Previous results showed that cold-induced stress results in suppression of the immune response and increased intensity of chlamydia genital infection in the mouse model. The purpose of the present study was to evaluate the potential therapeutic value of active hexose correlated compound (AHCC) against chlamydia genital infection in mice. AHCC is an extract of mushroom commonly used as a dietary supplement is known to boost the immune system. Mice were infected intravaginally with Chlamydia trachomatis after a 24-day cold-stress application. Oral administration of AHCC to stressed or non-stressed mice was carried out seven days before infection and during the course of infection along with cervicovaginal swabbing. Cytokine production by peritoneal and splenic T cells isolated from AHCC-fed stressed mice and non-stressed mice was measured ELISA. Splenic T cells from both animal groups were co-cultured with mouse monocyte J774.2 cell line or cultured by addition of supernatants of AHCC-treated J774.2 cell line for 24 hours. Infection studies showed that AHCC-feeding compared to phosphate buffered saline (PBS)-feeding to stressed mice resulted in reduced Chlamydia trachomatis shedding from the genital tract. Levels of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) were significantly increased in stressed mice receiving AHCC compared to stressed mice receiving PBS. Production of interferon gamma (IFN-γ) and interleukin 2 (IL-2) in the AHCC group was significantly high compared to production in PBS-fed group. Splenic T cells from stressed and non-stressed cultured with supernatants of AHCC-treated J774.2 cell line resulted in significantly increased TNF-α or IFN-γ production. Results obtained in this study show that AHCC improves the function of immune cells as indicated by the restoration of levels of cytokines

  11. Peroxisomal Monodehydroascorbate Reductase. Genomic Clone Characterization and Functional Analysis under Environmental Stress Conditions1

    PubMed Central

    Leterrier, Marina; Corpas, Francisco J.; Barroso, Juan B.; Sandalio, Luisa M.; del Río, Luis A.

    2005-01-01

    In plant cells, ascorbate is a major antioxidant that is involved in the ascorbate-glutathione cycle. Monodehydroascorbate reductase (MDAR) is the enzymatic component of this cycle involved in the regeneration of reduced ascorbate. The identification of the intron-exon organization and the promoter region of the pea (Pisum sativum) MDAR 1 gene was achieved in pea leaves using the method of walking polymerase chain reaction on genomic DNA. The nuclear gene of MDAR 1 comprises nine exons and eight introns, giving a total length of 3,770 bp. The sequence of 544 bp upstream of the initiation codon, which contains the promoter and 5′ untranslated region, and 190 bp downstream of the stop codon were also determined. The presence of different regulatory motifs in the promoter region of the gene might indicate distinct responses to various conditions. The expression analysis in different plant organs by northern blots showed that fruits had the highest level of MDAR. Confocal laser scanning microscopy analysis of pea leaves transformed with Agrobacterium tumefaciens having the binary vectors pGD, which contain the autofluorescent proteins enhanced green fluorescent protein and enhanced yellow fluorescent protein with the full-length cDNA for MDAR 1 and catalase, indicated that the MDAR 1 encoded the peroxisomal isoform. The functional analysis of MDAR by activity and protein expression was studied in pea plants grown under eight stress conditions, including continuous light, high light intensity, continuous dark, mechanical wounding, low and high temperature, cadmium, and the herbicide 2,4-dichlorophenoxyacetic acid. This functional analysis is representative of all the MDAR isoforms present in the different cell compartments. Results obtained showed a significant induction by high light intensity and cadmium. On the other hand, expression studies, performed by semiquantitative reverse transcription-polymerase chain reaction demonstrated differential expression patterns

  12. How emotional abilities modulate the influence of early life stress on hippocampal functioning

    PubMed Central

    Alkan Härtwig, Elif; Koelsch, Stefan; Heekeren, Hauke R.; Heuser, Isabella; Bajbouj, Malek

    2014-01-01

    Early life stress (ELS) is known to have considerable influence on brain development, mental health and affective functioning. Previous investigations have shown that alexithymia, a prevalent personality trait associated with difficulties experiencing and verbalizing emotions, is particularly related to ELS. The aim of the present study was to investigate how neural correlates of emotional experiences in alexithymia are altered in the presence and absence of ELS. Therefore, 50 healthy individuals with different levels of alexithymia were matched regarding ELS and investigated with respect to neural correlates of audio-visually induced emotional experiences via functional magnetic resonance imaging. The main finding was that ELS modulated hippocampal responses to pleasant (>neutral) stimuli in high-alexithymic individuals, whereas there was no such modulation in low-alexithymic individuals matched for ELS. Behavioral and psychophysiological results followed a similar pattern. When considered independent of ELS, alexithymia was associated with decreased responses in insula (pleasant > neutral) and temporal pole (unpleasant > neutral). Our results show that the influence of ELS on emotional brain responses seems to be modulated by an individual’s degree of alexithymia. Potentially, protective and adverse effects of emotional abilities on brain responses to emotional experiences are discussed. PMID:23685776

  13. Plant-specific CC-type glutaredoxins: functions in developmental processes and stress responses.

    PubMed

    Gutsche, Nora; Thurow, Corinna; Zachgo, Sabine; Gatz, Christiane

    2015-05-01

    Glutaredoxins (GRXs) are small oxidoreductases of the thioredoxin family proteins that can either regulate the thiol redox state of proteins or are linked to iron metabolism because of their ability to incorporate iron-sulfur [2Fe-2S] clusters. Here we review recent research on a land plant-specific class of GRX-like proteins, which are characterized by the conserved CC motif in the active centre. Loss-of-function mutants of CC-type GRXs in Arabidopsis (also named ROXYs), maize, and rice have unraveled a role in floral development, including regulation of organ primordia initiation, control of organ identity gene expression, and progression into meiosis in the male germ line. Other CC-type GRXs play a role in stress responses, most likely through their capacity to regulate nuclear gene expression. Consistently, CC-type GRXs, physically and genetically interact with individual members of the TGA transcription factor family. One of the challenges in the future is to unravel whether ROXYs control the redox state of TGA factors or other yet unknown target proteins or whether they regulate gene expression through other processes. Other intriguing questions concern the original function of the first CC-type GRXs in basal land plants and their potential contribution to the extremely successful radiation of angiosperms.

  14. Understanding the potency of stressful early life experiences on brain and body function.

    PubMed

    McEwen, Bruce S

    2008-10-01

    Early life experiences have powerful effects on the brain and body lasting throughout the entire life span and influencing brain function, behavior, and the risk for a number of systemic and mental disorders. Animal models of early life adversity are providing mechanistic insights, including glimpses into the fascinating world that is now called "epigenetics" as well as the role of naturally occurring alleles of a number of genes. These studies also provide insights into the adaptive value as well as the negative consequences, of early life stress, exposure to novelty, and poor-quality vs good-quality maternal care. Animal models begin to provide a mechanistic basis for understanding how brain development and physiological functioning is affected in children exposed to early life abuse and neglect, where there is a burgeoning literature on the consequences for physical health and emotional and cognitive development. An important goal is to identify interventions that are likely to be most effective in early life and some guidelines are provided. PMID:18803958

  15. Functional Neuroimaging of Emotionally Intense Autobiographical Memories in Post-Traumatic Stress Disorder

    PubMed Central

    St. Jacques, Peggy L.; Botzung, Anne; Miles, Amanda; Rubin, David C.

    2010-01-01

    Post-traumatic stress disorder (PTSD) affects regions that support autobiographical memory (AM) retrieval, such as the hippocampus, amygdala and ventral medial prefrontal cortex (PFC). However, it is not well understood how PTSD may impact the neural mechanisms of memory retrieval for the personal past. We used a generic cue method combined with parametric modulation analysis and functional MRI (fMRI) to investigate the neural mechanisms affected by PTSD symptoms during the retrieval of a large sample of emotionally intense AMs. There were three main results. First, the PTSD group showed greater recruitment of the amygdala/hippocampus during the construction of negative versus positive emotionally intense AMs, when compared to controls. Second, across both the construction and elaboration phases of retrieval the PTSD group showed greater recruitment of the ventral medial PFC for negatively intense memories, but less recruitment for positively intense memories. Third, the PTSD group showed greater functional coupling between the ventral medial PFC and the amygdala for negatively intense memories, but less coupling for positively intense memories. In sum, the fMRI data suggest that there was greater recruitment and coupling of emotional brain regions during the retrieval of negatively intense AMs in the PTSD group when compared to controls. PMID:21109253

  16. Altered resting-state amygdala functional connectivity in men with posttraumatic stress disorder

    PubMed Central

    Sripada, Rebecca K.; King, Anthony P.; Garfinkel, Sarah N.; Wang, Xin; Sripada, Chandra S.; Welsh, Robert C.; Liberzon, Israel

    2012-01-01

    Background Converging neuroimaging research suggests altered emotion neurocircuitry in individuals with posttraumatic stress disorder (PTSD). Emotion activation studies in these individuals have shown hyperactivation in emotion-related regions, including the amygdala and insula, and hypoactivation in emotion-regulation regions, including the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC). However, few studies have examined patterns of connectivity at rest in individuals with PTSD, a potentially powerful method for illuminating brain network structure. Methods Using the amygdala as a seed region, we measured resting-state brain connectivity using 3 T functional magnetic resonance imaging in returning male veterans with PTSD and combat controls without PTSD. Results Fifteen veterans with PTSD and 14 combat controls enrolled in our study. Compared with controls, veterans with PTSD showed greater positive connectivity between the amygdala and insula, reduced positive connectivity between the amygdala and hippocampus, and reduced anticorrelation between the amygdala and dorsal ACC and rostral ACC. Limitations Only male veterans with combat exposure were tested, thus our findings cannot be generalized to women or to individuals with non–combat related PTSD. Conclusion These results demonstrate that studies of functional connectivity during resting state can discern aberrant patterns of coupling within emotion circuits and suggest a possible brain basis for emotion-processing and emotion-regulation deficits in individuals with PTSD. PMID:22313617

  17. Yeast functional screen to identify genes conferring salt stress tolerance in Salicornia europaea

    PubMed Central

    Nakahara, Yoshiki; Sawabe, Shogo; Kainuma, Kenta; Katsuhara, Maki; Shibasaka, Mineo; Suzuki, Masanori; Yamamoto, Kosuke; Oguri, Suguru; Sakamoto, Hikaru

    2015-01-01

    Salinity is a critical environmental factor that adversely affects crop productivity. Halophytes have evolved various mechanisms to adapt to saline environments. Salicornia europaea L. is one of the most salt-tolerant plant species. It does not have special salt-secreting structures like a salt gland or salt bladder, and is therefore a good model for studying the common mechanisms underlying plant salt tolerance. To identify candidate genes encoding key proteins in the mediation of salt tolerance in S. europaea, we performed a functional screen of a cDNA library in yeast. The library was screened for genes that allowed the yeast to grow in the presence of 1.3 M NaCl. We obtained three full-length S. europaea genes that confer salt tolerance. The genes are predicted to encode (1) a novel protein highly homologous to thaumatin-like proteins, (2) a novel coiled-coil protein of unknown function, and (3) a novel short peptide of 32 residues. Exogenous application of a synthetic peptide corresponding to the 32 residues improved salt tolerance of Arabidopsis. The approach described in this report provides a rapid assay system for large-scale screening of S. europaea genes involved in salt stress tolerance and supports the identification of genes responsible for such mechanisms. These genes may be useful candidates for improving crop salt tolerance by genetic transformation. PMID:26579166

  18. Substrate recognition and function of the R2TP complex in response to cellular stress

    PubMed Central

    von Morgen, Patrick; Hořejší, Zuzana; Macurek, Libor

    2015-01-01

    The R2TP complex is a HSP90 co-chaperone, which consists of four subunits: PIH1D1, RPAP3, RUVBL1, and RUVBL2. It is involved in the assembly of large protein or protein–RNA complexes such as RNA polymerase, small nucleolar ribonucleoproteins (snoRNPs), phosphatidylinositol 3 kinase-related kinases (PIKKs), and their complexes. While RPAP3 has a HSP90 binding domain and the RUVBLs comprise ATPase activities important for R2TP functions, PIH1D1 contains a PIH-N domain that specifically recognizes phosphorylated substrates of the R2TP complex. In this review we provide an overview of the current knowledge of the R2TP complex with the focus on the recently identified structural and mechanistic features of the R2TP complex functions. We also discuss the way R2TP regulates cellular response to stress caused by low levels of nutrients or by DNA damage and its possible exploitation as a target for anti-cancer therapy. PMID:25767478

  19. c-Fos as a transcription factor: a stressful (re)view from a functional map.

    PubMed

    Kovács, K J

    1998-10-01

    This article summarizes the achievements that have been accumulated about the role of c-Fos as a transcription factor and as a functional marker of activated neurons. Since its discovery, more than a decade ago, as an inducible immediate-early gene encoding a transcription factor, or third messenger, involved in stimulus-transcription coupling and mediation of extracellular signals to long-term changes in cellular phenotype, c-fos became the most widely used powerful tool to delineate individual neurons as well as extended circuitries that are responsive to wide variety of external stimuli. There still remain uncertainties as to how general is the c-fos induction in the central neurons, and whether the threshold of c-fos induction is comparable along a certain neuronal circuit. The major limitation of this technology is that c-fos does not mark cells with a net inhibitory synaptic or transcriptional drive, and c-fos induction, as a generic marker of trans-synaptic activation, does not provide evidence for transcriptional activation of specific target genes in a certain cell type of interest. The first part of the review focuses on recent functional data on c-fos as transcription factor, while the second part discusses c-fos as a cellular marker of transcriptional activity in the stress-related circuitry.

  20. Podocyte-Specific Deletion of Murine CXADR Does Not Impair Podocyte Development, Function or Stress Response

    PubMed Central

    Schell, Christoph; Kretz, Oliver; Bregenzer, Andreas; Rogg, Manuel; Helmstädter, Martin; Lisewski, Ulrike; Gotthardt, Michael; Tharaux, Pierre-Louis; Huber, Tobias B.; Grahammer, Florian

    2015-01-01

    The coxsackie- and adenovirus receptor (CXADR) is a member of the immunoglobulin protein superfamily, present in various epithelial cells including glomerular epithelial cells. Beside its known function as a virus receptor, it also constitutes an integral part of cell-junctions. Previous studies in the zebrafish pronephros postulated a potential role of CXADR for the terminal differentiation of glomerular podocytes and correct patterning of the elaborated foot process architecture. However, due to early embryonic lethality of constitutive Cxadr knockout mice, mammalian data on kidney epithelial cells have been lacking. Interestingly, Cxadr is robustly expressed during podocyte development and in adulthood in response to glomerular injury. We therefore used a conditional transgenic approach to elucidate the function of Cxadr for podocyte development and stress response. Surprisingly, we could not discern a developmental phenotype in podocyte specific Cxadr knock-out mice. In addition, despite a significant up regulation of CXADR during toxic, genetic and immunologic podocyte injury, we could not detect any impact of Cxadr on these injury models. Thus these data indicate that in contrast to lower vertebrate models, mammalian podocytes have acquired molecular programs to compensate for the loss of Cxadr. PMID:26076477

  1. The matricellular protein thrombospondin-1 globally regulates cardiovascular function and responses to stress via CD47.

    PubMed

    Roberts, David D; Miller, Thomas W; Rogers, Natasha M; Yao, Mingyi; Isenberg, Jeffrey S

    2012-04-01

    Matricellular proteins play diverse roles in modulating cell behavior by engaging specific cell surface receptors and interacting with extracellular matrix proteins, secreted enzymes, and growth factors. Studies of such interactions involving thrombospondin-1 have revealed several physiological functions and roles in the pathogenesis of injury responses and cancer, but the relatively mild phenotypes of mice lacking thrombospondin-1 suggested that thrombospondin-1 would not be a central player that could be exploited therapeutically. Recent research focusing on signaling through its receptor CD47, however, has uncovered more critical roles for thrombospondin-1 in acute regulation of cardiovascular dynamics, hemostasis, immunity, and mitochondrial homeostasis. Several of these functions are mediated by potent and redundant inhibition of the canonical nitric oxide pathway. Conversely, elevated tissue thrombospondin-1 levels in major chronic diseases of aging may account for the deficient nitric oxide signaling that characterizes these diseases, and experimental therapeutics targeting CD47 show promise for treating such chronic diseases as well as acute stress conditions that are associated with elevated thrombospondin-1 expression.

  2. Understanding the potency of stressful early life experiences on brain and body function

    PubMed Central

    McEwen, Bruce S.

    2008-01-01

    Early life experiences have powerful effects on the brain and body lasting throughout the entire lifespan and influencing brain function, behavior and the risk for a number of systemic and mental disorders. Animal models of early life adversity are providing mechanistic insights, including glimpses into the fascinating world that is now called “epigenetics” as well as the role of naturally occurring alleles of a number of genes. These studies also provide insights into the adaptive value, as well as the negative consequences, of early life stress, exposure to novelty, and poor vs good quality maternal care. Animal models begin to provide a mechanistic basis for understanding how brain development and physiological functioning is affected in children exposed to early life abuse and neglect, where there is a burgeoning literature on the consequences for physical health and emotional and cognitive development. An important goal is to identify interventions that are likely to be most effective in early life and some guidelines are provided. PMID:18803958

  3. Perfusion functional MRI reveals cerebral blood flow pattern under psychological stress

    NASA Astrophysics Data System (ADS)

    Wang, Jiongjiong; Rao, Hengyi; Wetmore, Gabriel S.; Furlan, Patricia M.; Korczykowski, Marc; Dinges, David F.; Detre, John A.

    2005-12-01

    Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right prefrontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response. anterior cingulate cortex | arterial spin labeling | right prefrontal cortex

  4. Perfusion functional MRI reveals cerebral blood flow pattern under psychological stress

    PubMed Central

    Wang, Jiongjiong; Rao, Hengyi; Wetmore, Gabriel S.; Furlan, Patricia M.; Korczykowski, Marc; Dinges, David F.; Detre, John A.

    2005-01-01

    Despite the prevalence of stress in everyday life and its impact on happiness, health, and cognition, little is known about the neural substrate of the experience of everyday stress in humans. We use a quantitative and noninvasive neuroimaging technique, arterial spin-labeling perfusion MRI, to measure cerebral blood flow (CBF) changes associated with mild to moderate stress induced by a mental arithmetic task with performance monitoring. Elicitation of stress was verified by self-report of stress and emotional state and measures of heart rate and salivary-cortisol level. The change in CBF induced by the stress task was positively correlated with subjective stress rating in the ventral right prefrontal cortex (RPFC) and left insula/putamen area. The ventral RPFC along with right insula/putamen and anterior cingulate showed sustained activation after task completion in subjects reporting a high stress level during arithmetic tasks. Additionally, variations of baseline CBF in the ventral RPFC and right orbitofrontal cortex were found to correlate with changes in salivary-cortisol level and heart rate caused by undergoing stress tasks. We further demonstrated that the observed right prefrontal activation could not be attributed to increased cognitive demand accompanying stress tasks and extended beyond neural pathways associated with negative emotions. Our results provide neuroimaging evidence that psychological stress induces negative emotion and vigilance and that the ventral RPFC plays a key role in the central stress response. PMID:16306271

  5. Assessing Stress Reduction as a Function of Artistic Creation and Cognitive Focus

    ERIC Educational Resources Information Center

    Curl, Krista

    2008-01-01

    In this outcomes study (N=40), changes in stress levels were compared across two participant conditions for a period of artistic activity with a cognitive focus on either a personally stressful or positive situation. Results indicated that participants in the positive-focus condition demonstrated a significant decrease in stress, whereas…

  6. Interactive Contributions of Cumulative Peer Stress and Executive Function Deficits to Depression in Early Adolescence

    ERIC Educational Resources Information Center

    Agoston, Anna M.; Rudolph, Karen D.

    2016-01-01

    Exposure to peer stress contributes to adolescent depression, yet not all youth experience these effects. Thus, it is important to identify individual differences that shape the consequences of peer stress. This research investigated the interactive contribution of cumulative peer stress during childhood (second-fifth grades) and executive…

  7. Isolation of high salinity stress tolerant genes from Pisum sativum by random overexpression in Escherichia coli and their functional validation

    PubMed Central

    Joshi, Amita; Dang, Hung Quang; Vaid, Neha

    2009-01-01

    Salinity stress is one of the major factors which reduce crop plants growth and productivity resulting in significant economic losses worldwide. Therefore, it would be fruitful to isolate and functionally identify new salinity stress-induced genes for understanding the mechanism and developing salinity stress tolerant plants. Based on functional gene screening assay, we have isolated few salinity tolerant genes out of one million Escherichia coli (SOLR) transformants containing pea cDNAs. Sequence analysis of three of these genes revealed homology to Ribosomal-L30E (RPL30E), Chlorophyll-a/b-binding protein (Chla/bBP) and FIDDLEHEAD (FDH). The salinity tolerance of these genes in bacteria was further confirmed by using another strain of E. coli (DH5α) transformants. The homology based computational modeling of these proteins suggested the high degree of conservation with the conserved domains of their homologous partners. The reverse transcriptase polymerase chain reaction (RT-PCR) analysis showed that the expression of these cDNAs (except the FDH) was upregulated in pea plants in response to NaCl stress. We observed that there was no significant effect of Li+ ion on the expression level of these genes, while an increase in response to K+ ion was observed. Overall, this study provides an evidence for a novel function of these genes in high salinity stress tolerance. The PsFDH showed constitutive expression in planta suggesting that it can be used as constitutively expressed marker gene for salinity stress tolerance in plants. This study brings new direction in identifying novel function of unidentified genes in abiotic stress tolerance without previous knowledge of the genome sequence. PMID:19816097

  8. Stress cardiac MR imaging: the role of stress functional assessment and perfusion imaging in the evaluation of ischemic heart disease.

    PubMed

    Al Sayari, Saeed; Kopp, Sebastien; Bremerich, Jens

    2015-03-01

    Stress cardiac magnetic resonance imaging can provide valuable information for the diagnosis and management of ischemic heart disease (IHD). It plays an important role in the initial diagnosis in patients with acute chest pain, in the diagnosis of complications post myocardial infarction (MI), in the assessment of the right ventricle after an acute MI, to detect complications due to or after interventions, in prediction of myocardial recovery, to detect inducible ischemia in patients with known IHD, in differentiating ischemic from non-ischemic dilated cardiomyopathy, and in risk stratification.

  9. Stress cardiac MR imaging: the role of stress functional assessment and perfusion imaging in the evaluation of ischemic heart disease.

    PubMed

    Al Sayari, Saeed; Kopp, Sebastien; Bremerich, Jens

    2015-03-01

    Stress cardiac magnetic resonance imaging can provide valuable information for the diagnosis and management of ischemic heart disease (IHD). It plays an important role in the initial diagnosis in patients with acute chest pain, in the diagnosis of complications post myocardial infarction (MI), in the assessment of the right ventricle after an acute MI, to detect complications due to or after interventions, in prediction of myocardial recovery, to detect inducible ischemia in patients with known IHD, in differentiating ischemic from non-ischemic dilated cardiomyopathy, and in risk stratification. PMID:25727000

  10. Acute brief heat stress in late gestation alters neonatal calf innate immune functions.

    PubMed

    Strong, R A; Silva, E B; Cheng, H W; Eicher, S D

    2015-11-01

    Heat stress, as one of the environmental stressors affecting the dairy industry, compromises the cow milk production, immune function, and reproductive system. However, few studies have looked at how prenatal heat stress (HS) affects the offspring. The objective of this study was to evaluate the effect of HS during late gestation on calf immunity. Calves were born to cows exposed to evaporative cooling (CT) or HS (cyclic 23-35°C) for 1 wk at 3 wk before calving. Both bull and heifer calves (CT, n=10; HS, n=10) were housed in similar environmental temperatures after birth. Both CT and HS calves received 3.78 L of pooled colostrum within 12 h after birth and were fed the same diet throughout the study. In addition to tumor necrosis factor α, IL-1β, IL-1 receptor antagonist (IL-1RA), and toll-like receptor (TLR)2, and TLR4 mRNA expression, the expression of CD14(+) and CD18(+) cells, and DEC205(+) dendritic cells were determined in whole blood samples at d 0, 3, 7, 14, 21, and 28. The neutrophil to lymphocyte ratio, differential cell counts, and the hematocrit were also determined. During late gestation, the HS cows had greater respiration rates, rectal temperatures, and tended to spend more time standing compared with the CT cows. The HS calves had less expression of tumor necrosis factor-α and TLR2 and greater levels of IL-1β, IL-1RA, and TLR4 compared with CT calves. The HS calves also had a greater percentage of CD18(+) cells compared with the CT calves. Additionally, a greater percentage of neutrophils and lesser percentage of lymphocytes were in the HS calves compared with the CT calves. The results indicate that biomarkers of calves' immunity are affected in the first several weeks after birth by HS in the dam during late gestation. PMID:26298746

  11. Controlled human wood smoke exposure: oxidative stress, inflammation and microvascular function

    PubMed Central

    2012-01-01

    Background Exposure to wood smoke is associated with respiratory symptoms, whereas knowledge on systemic effects is limited. We investigated effects on systemic inflammation, oxidative stress and microvascular function (MVF) after controlled wood smoke exposure. Methods In a randomised, double-blinded, cross-over study 20 non-smoking atopic subjects were exposed at rest to 14, 220, or 354 μg/m3 of particles from a well-burning modern wood stove for 3 h in a climate controlled chamber with 2 week intervals. We investigated the level of oxidatively damaged DNA, inflammatory markers and adhesion molecules before and 0, 6 and 20 h after exposure. Six h after exposure we measured MVF non-invasively by digital peripheral artery tonometry following arm ischemia. Results The MVF score was unaltered after inhalation of clean air (1.58 ± 0.07; mean ± SEM), low (1.51 ± 0.07) or high (1.61 ± 0.09) concentrations of wood smoke particles in atopic subjects, whereas unexposed non-atopic subjects had higher score (1.91 ± 0.09). The level of oxidatively damaged DNA, mRNA of ITGAL, CCL2, TNF, IL6, IL8, HMOX1, and OGG1 and surface marker molecules ICAM1, ITGAL and L-selectin in peripheral blood mononuclear cells were not affected by inhalation of wood smoke particles. Conclusions Exposure to wood smoke had no effect on markers of oxidative stress, DNA damage, cell adhesion, cytokines or MVF in atopic subjects. PMID:22452928

  12. Alterations of CNS structure & function by charged particle radiation & resultant oxidative stress

    NASA Astrophysics Data System (ADS)

    Nelson, Gregory; Chang, Polly; Favre, Cecile; Fike, John; Komarova, Natalia; Limoli, Charles; Mao, Xiao-Wen; Obenaus, Andre; Raber, Jacob; Spigelman, Igor; Soltesz, Ivan; Song, Sheng-Kwei; Stampanoni, Marco; Vlkolinsky, Roman; Wodarz, Dominik

    were complex and suggested continuous remodeling of the brain for up to 6 months. Thus we demonstrated a suite of CNS structural and functional changes after proton and iron ion exposure in the low dose regime. Based on these findings we will now test whether oxidative stress mediates the reactions of CNS to radiation exposure and what role radiation quality and dose rate play in the responses. We will use cultured neural precursor cells (mouse human) to detect changes in oxidative status and differentiation as functions of charged particle charge and velocity. These results will inform the selection of particles for many in vivo measurements that will compare wild type mice to a transgenic strain that over-expresses a human catalase gene (which inactivates hydrogen peroxide) in the mitochondrial compartment. This will explicitly test the role of reactive oxygen species in mediating the mechanisms underlying the CNS endpoints that we will measure. We will extend the electrophysiological measurements on individual nerves in hippocampal slices to characterize both inhibitory and excitatory synapses. Further, multi-electrode arrays will be used to follow correlated electrical activity in different hippocampal regions in order to understand network-level function as well as synaptic efficacy and plasticity. Controlled oxidative stress on irradiated samples will explore whether response mechanisms are shared. To link alterations in neurogenesis to performance we will explore behavioral changes mediated by the hippocampus simultaneously with measures of expression of the Arc gene in newly-born neurons. This will test whether decrements in performance correlate with loss of new cells and whether behavior properly stimulates functional integration of the new cells; the behavioral paradigm will be contextual fear conditioning. We will develop mathematical frameworks for CNS responses to radiation in order to inform risk estimates. Finally, we will couple a high

  13. Prenatal Stress Produces Persistence of Remote Memory and Disrupts Functional Connectivity in the Hippocampal-Prefrontal Cortex Axis.

    PubMed

    Negrón-Oyarzo, Ignacio; Neira, David; Espinosa, Nelson; Fuentealba, Pablo; Aboitiz, Francisco

    2015-09-01

    Prenatal stress is a risk factor for the development of neuropsychiatric disorders, many of which are commonly characterized by an increased persistence of aversive remote memory. Here, we addressed the effect of prenatal stress on both memory consolidation and functional connectivity in the hippocampal-prefrontal cortex axis, a dynamical interplay that is critical for mnemonic processing. Pregnant mice of the C57BL6 strain were subjected to restraint stressed during the last week of pregnancy, and male offspring were behaviorally tested at adulthood for recent and remote spatial memory performance in the Barnes Maze test under an aversive context. Prenatal stress did not affect the acquisition or recall of recent memory. In contrast, it produced the persistence of remote spatial memory. Memory persistence was not associated with alterations in major network rhythms, such as hippocampal sharp-wave ripples (SWRs) or neocortical spindles. Instead, it was associated with a large decrease in the basal discharge activity of identified principal neurons in the medial prefrontal cortex (mPFC) as measured in urethane anesthetized mice. Furthermore, functional connectivity was disrupted, as the temporal coupling between neuronal discharge in the mPFC and hippocampal SWRs was decreased by prenatal stress. These results could be relevant to understand the biological basis of the persistence of aversive remote memories in stress-related disorders.

  14. Methylphenidate and environmental enrichment ameliorate the deleterious effects of prenatal stress on attention functioning.

    PubMed

    Zubedat, Salman; Aga-Mizrachi, Shlomit; Cymerblit-Sabba, Adi; Ritter, Ami; Nachmani, Maayan; Avital, Avi

    2015-01-01

    Either pre- or post-natal environmental factors seem to play a key role in brain and behavioral development and to exert long-term effects. Increasing evidence suggests that exposure to prenatal stress (PS) leads to motor and learning deficits and elevated anxiety, while enriched environment (EE) shows protective effects. The dopaminergic system is also sensitive to environmental life circumstances and affects attention functioning, which serves as the preliminary gate to cognitive processes. However, the effects of methylphenidate (MPH) on the dopaminergic system and attentional functioning, in the context of these life experiences, remain unclear. Therefore, we aimed to examine the effects of EE or PS on distinct types of attention, along with possible effects of MPH exposure. We found that PS impaired selective attention as well as partial sustained attention, while EE had beneficial effects. Both EE and MPH ameliorated the deleterious effects of PS on attention functioning. Considering the possible psychostimulant effect of MPH, we examined both anxiety-like behavior as well as motor learning. We found that PS had a clear anxiogenic effect, whereas EE had an anxiolytic effect. Nevertheless, the treatment with both MPH and/or EE recovered the deleterious effects of PS. In the motor-learning task, the PS group showed superior performance while MPH led to impaired motor learning. Performance decrements were prevented in both the PS + MPH and EE + MPH groups. This study provides evidence that peripubertal exposure to EE (by providing enhanced sensory, motor, and social opportunities) or MPH treatments might be an optional therapeutic intervention in preventing the PS long-term adverse consequences.

  15. Elucidating dimensions of posttraumatic stress symptoms and their functional correlates in disaster-exposed adolescents.

    PubMed

    Sumner, Jennifer A; Pietrzak, Robert H; Danielson, Carla Kmett; Adams, Zachary W; Ruggiero, Kenneth J

    2014-12-01

    The aim of this study was to elucidate the dimensional structure of posttraumatic stress disorder (PTSD) and potential moderators and functional correlates of this structure in disaster-affected adolescents. A population-based sample of 2000 adolescents aged 12-17 years (M = 14.5 years; 51% female) completed interviews on post-tornado PTSD symptoms, substance use, and parent-adolescent conflict between 4 and 13 months (M = 8.8, SD = 2.6) after tornado exposure. Confirmatory factor analyses revealed that all models fit well but a 5-factor dysphoric arousal model provided a statistically significantly better representation of adolescent PTSD symptoms compared to 4-factor dysphoria and emotional numbing models. There was evidence of measurement invariance of the dysphoric arousal model across gender and age, although girls and older adolescents aged 15-17 years had higher mean scores than boys and younger adolescents aged 12-14 years, respectively, on some PTSD dimensions. Differential magnitudes of association between PTSD symptom dimensions and functional correlates were observed, with emotional numbing symptoms most strongly positively associated with problematic substance use since the tornado, and dysphoric arousal symptoms most strongly positively associated with parent-adolescent conflict; both correlations were significantly larger than the corresponding correlations with anxious arousal. Taken together, these results suggest that the dimensional structure of tornado-related PTSD symptomatology in adolescents is optimally characterized by five separate clusters of re-experiencing, avoidance, numbing, dysphoric arousal, and anxious arousal symptoms, which showed unique associations with functional correlates. Findings emphasize that PTSD in disaster-exposed adolescents is not best conceptualized as a homogenous construct and highlight potential differential targets for post-disaster assessment and intervention.

  16. Elucidating Dimensions of Posttraumatic Stress Symptoms and their Functional Correlates in Disaster-Exposed Adolescents

    PubMed Central

    Sumner, Jennifer A.; Pietrzak, Robert H.; Danielson, Carla Kmett; Adams, Zachary W.; Ruggiero, Kenneth J.

    2014-01-01

    The aim of this study was to elucidate the dimensional structure of posttraumatic stress disorder (PTSD) and potential moderators and functional correlates of this structure in disaster-affected adolescents. A population-based sample of 2,000 adolescents aged 12–17 years (M=14.5 years; 51% female) completed interviews on post-tornado PTSD symptoms, substance use, and parent-adolescent conflict between 4 and 13 months (M=8.8, SD=2.6) after tornado exposure. Confirmatory factor analyses revealed that all models fit well but a 5-factor dysphoric arousal model provided a statistically significantly better representation of adolescent PTSD symptoms compared to 4-factor dysphoria and emotional numbing models. There was evidence of measurement invariance of the dysphoric arousal model across gender and age, although girls and older adolescents aged 15–17 years had higher mean scores than boys and younger adolescents aged 12–14 years, respectively, on some PTSD dimensions. Differential magnitudes of association between PTSD symptom dimensions and functional correlates were observed, with emotional numbing symptoms most strongly positively associated with problematic substance use since the tornado, and dysphoric arousal symptoms most strongly positively associated with parent-adolescent conflict; both correlations were significantly larger than the corresponding correlations with anxious arousal. Taken together, these results suggest that the dimensional structure of tornado-related PTSD symptomatology in adolescents is optimally characterized by five separate clusters of re-experiencing, avoidance, numbing, dysphoric arousal, and anxious arousal symptoms, which showed unique associations with functional correlates. Findings emphasize that PTSD in disaster-exposed adolescents is not best conceptualized as a homogeneous construct and highlight potential differential targets for post-disaster assessment and intervention. PMID:25248557

  17. Viscosity and stress autocorrelation function in supercooled water: a molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Guo, Guang-Jun; Zhang, Yi-Gang; Refson, Keith; Zhao, Ya-Juan

    Following GUO, G.-J., and ZHANG, Y.-G., 2001, Molec. Phys. , 99 , 283, which calculates the bulk and shear viscosities of SPC/E water at 30°C and 0.999gcm -3 , further molecular dynamics simulations have been performed at state points of 0°C,-20°C,-40°C, and -60°C along an approximate isobar with the previous state point. SACF and BACF (stress autocorrelation functions related to shear and bulk viscosities, respectively) of high precision have been obtained and compared for their similarities and differences. Shear and bulk viscosities calculated from them showed an increased deviation from real water with decreasing temperature. These correlation functions were then fitted using a uniform two-step relaxation function including a fast oscillatory Kohlrausch law and a slow straightforward Kohlrausch law. The fitting parameters of SACF and BACF have been analysed in detail, and several interesting dynamic phenomena were observed. (1) The oscillation frequency of SACF (44 ~ 48ps -1 ) for short time intervals agrees with the stretching mode of hydrogen bonds, while that of BACF (7 ~ 12ps -1 ) agrees with the bending mode of hydrogen bonds. (2) With decreasing temperature, the slow relaxation fraction of the BACF increases, while that of the SACF remains constant. (3) The exponents βin the Kohlrausch laws with values greater than 1 are obtained for BACF at ambient temperatures. (4) With regard to both shear and bulk viscosities, the slow relaxation time largely increases with decreasing temperature, while the fast relaxation time slightly decreases. These phenomena are qualitatively explained and discussed.

  18. A quantitative meta-analysis of neurocognitive functioning in posttraumatic stress disorder

    PubMed Central

    Scott, J. Cobb; Matt, Georg E.; Wrocklage, Kristen M.; Crnich, Cassandra; Jordan, Jessica; Southwick, Steven M.; Krystal, John H.; Schweinsburg, Brian C.

    2014-01-01

    Posttraumatic stress disorder (PTSD) is associated with regional alterations in brain structure and function that are hypothesized to contribute to symptoms and cognitive deficits associated with the disorder. We present here the first systematic meta-analysis of neurocognitive outcomes associated with PTSD to examine a broad range of cognitive domains and describe the profile of cognitive deficits, as well as modifying clinical factors and study characteristics. This report is based on data from 60 studies totaling 4,108 participants, including 1,779with PTSD, 1,446 trauma-exposed comparison participants, and 895 healthy comparison participants without trauma exposure. Effect size estimates were calculated using a mixed-effects meta-analysis for nine cognitive domains: attention/working memory, executive functions, verbal learning, verbal memory, visual learning, visual memory, language, speed of information processing, and visuospatial abilities. Analyses revealed significant neurocognitive effects associated with PTSD, although these ranged widely in magnitude, with the largest effect sizes in verbal learning (d =−.62), speed of information processing (d =−.59), attention/working memory (d =−.50), and verbal memory (d =−.46). Effect size estimates were significantly larger in treatment-seeking than community samples and in studies that did not exclude participants with attention-deficit hyperactivity disorder, and effect sizes were affected by between-group IQ discrepancies and the gender composition of the PTSD groups. Our findings indicate that consideration of neuropsychological functioning in attention, verbal memory, and speed of information processing may have important implications for the effective clinical management of persons with PTSD. Results are further discussed in the context of cognitive models of PTSD and the limitations of this literature. PMID:25365762

  19. Successive deep dives impair endothelial function and enhance oxidative stress in man.

    PubMed

    Obad, Ante; Marinovic, Jasna; Ljubkovic, Marko; Breskovic, Toni; Modun, Darko; Boban, Mladen; Dujic, Zeljko

    2010-11-01

    The aim of this study was to assess the effects of successive deep dives on endothelial function of large conduit arteries and plasma pro-oxidant and antioxidant activity. Seven experienced divers performed six dives in six consecutive days using a compressed mixture of oxygen, helium and nitrogen (trimix) with diving depths ranging from 55 to 80 m. Before and after first, third and sixth dive, venous gas emboli formation and brachial artery function (flow-mediated dilation, FMD) was assessed by ultrasound. In addition, plasma antioxidant capacity (AOC) was measured by ferric reducing antioxidant power, and the level of oxidative stress was assessed by thiobarbituric acid-reactive substances (TBARS) method. Although the FMD was reduced to a similar extent after each dive, the comparison of predive FMD showed a reduction from 8.6% recorded before the first dive to 6.3% before the third (P = 0.03) and 5.7% before the sixth dive (P = 0.003). A gradual shift in baseline was also detected with TBARS assay, with malondialdehyde values increasing from 0.10 ± 0.02 μmol l⁻¹ before the first dive to 0.16 ± 0.03 before the sixth (P = 0.005). Predive plasma AOC values also showed a decreasing trend from 0.67 ± 0.20 mmol l⁻¹ trolox equivalents (first day) to 0.56 ± 0.12 (sixth day), although statistical significance was not reached (P = 0.08). This is the first documentation of acute endothelial dysfunction in the large conduit arteries occurring after successive deep trimix dives. Both endothelial function and plasma pro-oxidant and antioxidant activity did not return to baseline during the course of repetitive dives, indicating possible cumulative and longer lasting detrimental effects.

  20. Elucidating dimensions of posttraumatic stress symptoms and their functional correlates in disaster-exposed adolescents.

    PubMed

    Sumner, Jennifer A; Pietrzak, Robert H; Danielson, Carla Kmett; Adams, Zachary W; Ruggiero, Kenneth J

    2014-12-01

    The aim of this study was to elucidate the dimensional structure of posttraumatic stress disorder (PTSD) and potential moderators and functional correlates of this structure in disaster-affected adolescents. A population-based sample of 2000 adolescents aged 12-17 years (M = 14.5 years; 51% female) completed interviews on post-tornado PTSD symptoms, substance use, and parent-adolescent conflict between 4 and 13 months (M = 8.8, SD = 2.6) after tornado exposure. Confirmatory factor analyses revealed that all models fit well but a 5-factor dysphoric arousal model provided a statistically significantly better representation of adolescent PTSD symptoms compared to 4-factor dysphoria and emotional numbing models. There was evidence of measurement invariance of the dysphoric arousal model across gender and age, although girls and older adolescents aged 15-17 years had higher mean scores than boys and younger adolescents aged 12-14 years, respectively, on some PTSD dimensions. Differential magnitudes of association between PTSD symptom dimensions and functional correlates were observed, with emotional numbing symptoms most strongly positively associated with problematic substance use since the tornado, and dysphoric arousal symptoms most strongly positively associated with parent-adolescent conflict; both correlations were significantly larger than the corresponding correlations with anxious arousal. Taken together, these results suggest that the dimensional structure of tornado-related PTSD symptomatology in adolescents is optimally characterized by five separate clusters of re-experiencing, avoidance, numbing, dysphoric arousal, and anxious arousal symptoms, which showed unique associations with functional correlates. Findings emphasize that PTSD in disaster-exposed adolescents is not best conceptualized as a homogenous construct and highlight potential differential targets for post-disaster assessment and intervention. PMID:25248557

  1. The K-segments of wheat dehydrin WZY2 are essential for its protective functions under temperature stress

    PubMed Central

    Yang, Wenbo; Zhang, Linsheng; Lv, Hui; Li, He; Zhang, Yane; Xu, Yang; Yu, Jianing

    2015-01-01

    Dehydrins (DHNs), group 2 of late embryogenesis abundant (LEA) proteins, are up-regulated in most plants during cold, drought, heat, or salinity stress. All DHNs contain at least one K-segment, which is believed to play a significant role in DHN function by forming an amphipathic helix. In previous studies, wzy2, an YSK2-type DHN gene, was isolated from the Zhengyin 1 cultivar of Triticum aestivum under cold and drought stress treatment conditions. Four WZY2 truncated derivatives were constructed to knock out the K-, Y- or S-segment, which potentially affect the function of the protein. In vivo assays of Escherichia coli viability enhancement, in vitro lactate dehydrogenase (LDH) activity protection and ex vivo protein aggregation prevention assays revealed that WZY2 acted as a protectant and improved stress tolerance during temperature variation. The results also showed that unlike the truncated derivative without K-segments, the derivative containing two K-segments had remarkable effects that were similar to those of full-length WZY2, indicating that the K-segment is the major functional component of WZY2. Moreover, compared with the other segments, the first K-segment might be the most critical contributor to WZY2 functionality. In general, this work highlights the behavior of DHNs in relieving cold stress ex vivo and the contribution of the K-segment to DHN function. PMID:26124763

  2. The K-segments of wheat dehydrin WZY2 are essential for its protective functions under temperature stress.

    PubMed

    Yang, Wenbo; Zhang, Linsheng; Lv, Hui; Li, He; Zhang, Yane; Xu, Yang; Yu, Jianing

    2015-01-01

    Dehydrins (DHNs), group 2 of late embryogenesis abundant (LEA) proteins, are up-regulated in most plants during cold, drought, heat, or salinity stress. All DHNs contain at least one K-segment, which is believed to play a significant role in DHN function by forming an amphipathic helix. In previous studies, wzy2, an YSK2-type DHN gene, was isolated from the Zhengyin 1 cultivar of Triticum aestivum under cold and drought stress treatment conditions. Four WZY2 truncated derivatives were constructed to knock out the K-, Y- or S-segment, which potentially affect the function of the protein. In vivo assays of Escherichia coli viability enhancement, in vitro lactate dehydrogenase (LDH) activity protection and ex vivo protein aggregation prevention assays revealed that WZY2 acted as a protectant and improved stress tolerance during temperature variation. The results also showed that unlike the truncated derivative without K-segments, the derivative containing two K-segments had remarkable effects that were similar to those of full-length WZY2, indicating that the K-segment is the major functional component of WZY2. Moreover, compared with the other segments, the first K-segment might be the most critical contributor to WZY2 functionality. In general, this work highlights the behavior of DHNs in relieving cold stress ex vivo and the contribution of the K-segment to DHN function. PMID:26124763

  3. Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus

    PubMed Central

    Cario, Anaïs; Jebbar, Mohamed; Thiel, Axel; Kervarec, Nelly; Oger, Phil M.

    2016-01-01

    The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response. PMID:27378270

  4. Race/ethnic and socioeconomic differences in stress and immune function in The National Longitudinal Study of Adolescent Health.

    PubMed

    Dowd, Jennifer B; Palermo, Tia; Chyu, Laura; Adam, Emma; McDade, Thomas W

    2014-08-01

    Stress and immune function may be important mediators of the strong association between social factors and health over the life course, but previous studies have lacked the data to fully explore these links in a population-based sample. This study utilizes data from Waves I-IV of the U.S. National Longitudinal Study of Adolescent Health (Add Health) to test the associations of race/ethnicity and socioeconomic status (SES) with levels of perceived stress and exposure to stressful life events (SLE) among 11,050 adult respondents aged 24-32 in 2008-2009. We further tested whether race/ethnicity and SES were associated with Epstein-Barr Virus (EBV) specific IgG antibodies, an indirect marker of cell-mediated immune function. Finally, we tested whether measures of stress were associated with EBV IgG and whether there was evidence that they explain any associations between race/ethnicity, SES and EBV IgG. We found strong associations between lower SES and higher levels of perceived stress (OR 2.07, 95% CI 1.73-2.48 for < high school vs. college or above) and a high level of stressful life events (OR 7.47, 95% CI 5.59-9.98 for < high school vs. college or above). Blacks had higher odds of a high level of stressful life events compared to whites (OR 2.00, 95% CI 1.63-2.47), but not higher perceived stress (OR 1.11, 95% CI 0.96-1.28). Blacks also had significantly higher EBV levels compared to whites (β = 0.136, p < 0.01), but lower SES was not associated with higher EBV IgG. We found no evidence that stressful life events or perceived stress were associated with EBV IgG in this sample, and thus did not account for racial differences in EBV IgG. These results suggest consistent race/ethnic and SES differences in stressful life events, and confirm race/ethnic differences in markers of immune function that may have health implications across the life course.

  5. Hypoxia-induced and stress-specific changes in chromatin structure and function.

    PubMed

    Johnson, Amber Buescher; Barton, Michelle Craig

    2007-05-01

    Cellular adaptation to stress relies on specific, regulated responses to evoke changes in gene expression. Stresses such as hypoxia, heat shock, oxidative stress and DNA-damage activate signaling cascades that ultimately lead to either induction or repression of stress-responsive genes. In this review, we concentrate on the mechanisms by which stress-induced signaling promotes alterations in chromatin structure, whether the read-out is activation or repression of transcription. Specific alterations in chromatin are highly regulated and dictated by the type of imposed stress. Our primary focus is on the types of chromatin alterations that occur under hypoxic conditions, which exist within a majority of tumors, and to compare these to changes in chromatin structure that occur in response to a wide variety of cellular stresses.

  6. Hypoxia-induced and stress-specific changes in chromatin structure and function

    PubMed Central

    Johnson, Amber Buescher; Barton, Michelle Craig

    2007-01-01

    Cellular adaptation to stress relies on specific, regulated responses to evoke changes in gene expression. Stresses such as hypoxia, heat shock, oxidative stress and DNA-damage activate signaling cascades that ultimately lead to either induction or repression of stress-responsive genes. In this review, we concentrate on the mechanisms by which stress-induced signaling promotes alterations in chromatin structure, whether the read-out is activation or repression of transcription. Specific alterations in chromatin are highly regulated and dictated by the type of imposed stress. Our primary focus is on the types of chromatin alterations that occur under hypoxic conditions, which exist within a majority of tumors, and to compare these to changes in chromatin structure that occur in response to a wide variety of cellular stresses. PMID:17292925

  7. The Relationship of Metabolic Syndrome with Stress, Coronary Heart Disease and Pulmonary Function - An Occupational Cohort-Based Study

    PubMed Central

    Nowobilski, Roman; Dropinski, Jerzy; Kotula-Horowitz, Katarzyna; Laskowicz, Bartosz; Stanisz, Andrzej; Lelakowski, Jacek

    2015-01-01

    Background and Aims Higher levels of stress impact the prevalence of metabolic syndrome (MetS) and coronary heart disease. The association between MetS, impaired pulmonary function and low level of physical activity is still pending assessment in the subjects exposed to stress. The study aimed to examine whether higher levels of stress might be related to MetS and the plaque presence, as well as whether MetS might affect pulmonary function. Design and Methods The study embraced 235 police officers (mean age 40.97 years) from the south of Poland. The anthropometrics and biochemical variables were measured; MetS was diagnosed using the International Diabetes Federation criteria. Computed tomography coronary angiography of coronary arteries, exercise ECG, measurements of brachial flow-mediated dilation, and carotid artery intima-media thickness were completed. In order to measure the self-perception of stress, 10-item Perceived Stress Scale (PSS-10) was applied. Pulmonary function and physical activity levels were also addressed. Multivariate logistic regression analyses were applied to determine the relationships between: 1/ incidence of coronary plaque and MetS per se, MetS components and the number of classical cardiovascular risk factors, 2/ perceived stress and MetS, 3/ MetS and pulmonary function parameters. Results Coronary artery atherosclerosis was less associated with MetS (OR = 2.62, 95%CI 1.24–5.52; p = 0.011) than with a co-existence of classical cardiovascular risk factors (OR = 5.67, 95% CI 1.07–29.85, p = 0.03; for 3 risk factors and OR = 9.05; 95% CI 1.24–66.23, p = 0.02; for 6 risk factors, respectively). Perceived stress increased MetS prevalence (OR = 1.07, 95% CI 1.03–1.13; p = 0.03), and impacted coronary plaque prevalence (OR = 1.05, 95% CI 1.001–1.10; p = 0.04). Leisure-time physical activity reduced the chances of developing MetS (OR = 0.98 95% CI 0.96–0.99; p = 0.02). MetS subjects had significantly lower values of certain

  8. Loss of Arabidopsis 5'-3' Exoribonuclease AtXRN4 Function Enhances Heat Stress Tolerance of Plants Subjected to Severe Heat Stress.

    PubMed

    Nguyen, Anh Hai; Matsui, Akihiro; Tanaka, Maho; Mizunashi, Kayoko; Nakaminami, Kentaro; Hayashi, Makoto; Iida, Kei; Toyoda, Tetsuro; Nguyen, Dong Van; Seki, Motoaki

    2015-09-01

    mRNA degradation plays an important role in the rapid and dynamic alteration of gene expression in response to environmental stimuli. Arabidopsis 5'-3' exoribonuclease (AtXRN4), a homolog of yeast Xrn1p, functions after a de-capping step in the degradation of uncapped RNAs. While Xrn1p-dependent degradation of mRNA is the main process of mRNA decay in yeast, information pertaining to the targets of XRN4-based degradation in plants is limited. In order to better understand the biological function of AtXRN4, the current study examined the survivability of atxrn4 mutants subjected to heat stress. The results indicated that atxrn4 mutants, compared with wild-type plants, exhibited an increased survival rate when subjected to a short-term severe heat stress. A microarray and mRNA decay assay showed that loss of AtXRN4 function caused a reduction in the degradation of heat shock factor A2 (HSFA2) and ethylene response factor 1 (ERF1) mRNA. The heat stress tolerance phenotype of atxrn4 mutants was significantly reduced or lost by mutation of HSFA2, a known key regulator of heat acclimation, thus indicating that HSFA2 is a target gene of AtXRN4-mediated mRNA degradation both under non-stress conditions and during heat acclimation. These results demonstrate that AtXRN4-mediated mRNA degradation is linked to the suppression of heat acclimation. PMID:26136597

  9. Do biotic interactions modulate ecosystem functioning along stress gradients? Insights from semi-arid plant and biological soil crust communities

    PubMed Central

    Maestre, Fernando T.; Bowker, Matthew A.; Escolar, Cristina; Puche, María D.; Soliveres, Santiago; Maltez-Mouro, Sara; García-Palacios, Pablo; Castillo-Monroy, Andrea P.; Martínez, Isabel; Escudero, Adrián

    2010-01-01

    Climate change will exacerbate the degree of abiotic stress experienced by semi-arid ecosystems. While abiotic stress profoundly affects biotic interactions, their potential role as modulators of ecosystem responses to climate change is largely unknown. Using plants and biological soil crusts, we tested the relative importance of facilitative–competitive interactions and other community attributes (cover, species richness and species evenness) as drivers of ecosystem functioning along stress gradients in semi-arid Mediterranean ecosystems. Biotic interactions shifted from facilitation to competition along stress gradients driven by water availability and temperature. These changes were, however, dependent on the spatial scale and the community considered. We found little evidence to suggest that biotic interactions are a major direct influence upon indicators of ecosystem functioning (soil respiration, organic carbon, water-holding capacity, compaction and the activity of enzymes related to the carbon, nitrogen and phosphorus cycles) along stress gradients. However, attributes such as cover and species richness showed a direct effect on ecosystem functioning. Our results do not agree with predictions emphasizing that the importance of plant–plant interactions will be increased under climate change in dry environments, and indicate that reductions in the cover of plant and biological soil crust communities will negatively impact ecosystems under future climatic conditions. PMID:20513714

  10. Taxonomic and Functional Diversity Provides Insight into Microbial Pathways and Stress Responses in the Saline Qinghai Lake, China

    PubMed Central

    Dong, Hailiang; Jiang, Hongchen; Wu, Geng; Edwardson, Christian; De Vlaminck, Iwijn; Quake, Stephen

    2014-01-01

    Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity) on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m) saline (1.4%) lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E). Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change. PMID:25365331

  11. Taxonomic and functional diversity provides insight into microbial pathways and stress responses in the saline Qinghai Lake, China.

    PubMed

    Huang, Qiuyuan; Briggs, Brandon R; Dong, Hailiang; Jiang, Hongchen; Wu, Geng; Edwardson, Christian; De Vlaminck, Iwijn; Quake, Stephen

    2014-01-01

    Microbe-mediated biogeochemical cycles contribute to the global climate system and have sensitive responses and feedbacks to environmental stress caused by climate change. Yet, little is known about the effects of microbial biodiversity (i.e., taxonmic and functional diversity) on biogeochemical cycles in ecosytems that are highly sensitive to climate change. One such sensitive ecosystem is Qinghai Lake, a high-elevation (3196 m) saline (1.4%) lake located on the Tibetan Plateau, China. This study provides baseline information on the microbial taxonomic and functional diversity as well as the associated stress response genes. Illumina metagenomic and metatranscriptomic datasets were generated from lake water samples collected at two sites (B and E). Autotrophic Cyanobacteria dominated the DNA samples, while heterotrophic Proteobacteria dominated the RNA samples at both sites. Photoheterotrophic Loktanella was also present at both sites. Photosystem II was the most active pathway at site B; while, oxidative phosphorylation was most active at site E. Organisms that expressed photosystem II or oxidative phosphorylation also expressed genes involved in photoprotection and oxidative stress, respectively. Assimilatory pathways associated with the nitrogen cycle were dominant at both sites. Results also indicate a positive relationship between functional diversity and the number of stress response genes. This study provides insight into the stress resilience of microbial metabolic pathways supported by greater taxonomic diversity, which may affect the microbial community response to climate change. PMID:25365331

  12. Alterations of CNS structure & function by charged particle radiation & resultant oxidative stress

    NASA Astrophysics Data System (ADS)

    Nelson, Gregory; Chang, Polly; Favre, Cecile; Fike, John; Komarova, Natalia; Limoli, Charles; Mao, Xiao-Wen; Obenaus, Andre; Raber, Jacob; Spigelman, Igor; Soltesz, Ivan; Song, Sheng-Kwei; Stampanoni, Marco; Vlkolinsky, Roman; Wodarz, Dominik

    were complex and suggested continuous remodeling of the brain for up to 6 months. Thus we demonstrated a suite of CNS structural and functional changes after proton and iron ion exposure in the low dose regime. Based on these findings we will now test whether oxidative stress mediates the reactions of CNS to radiation exposure and what role radiation quality and dose rate play in the responses. We will use cultured neural precursor cells (mouse human) to detect changes in oxidative status and differentiation as functions of charged particle charge and velocity. These results will inform the selection of particles for many in vivo measurements that will compare wild type mice to a transgenic strain that over-expresses a human catalase gene (which inactivates hydrogen peroxide) in the mitochondrial compartment. This will explicitly test the role of reactive oxygen species in mediating the mechanisms underlying the CNS endpoints that we will measure. We will extend the electrophysiological measurements on individual nerves in hippocampal slices to characterize both inhibitory and excitatory synapses. Further, multi-electrode arrays will be used to follow correlated electrical activity in different hippocampal regions in order to understand network-level function as well as synaptic efficacy and plasticity. Controlled oxidative stress on irradiated samples will explore whether response mechanisms are shared. To link alterations in neurogenesis to performance we will explore behavioral changes mediated by the hippocampus simultaneously with measures of expression of the Arc gene in newly-born neurons. This will test whether decrements in performance correlate with loss of new cells and whether behavior properly stimulates functional integration of the new cells; the behavioral paradigm will be contextual fear conditioning. We will develop mathematical frameworks for CNS responses to radiation in order to inform risk estimates. Finally, we will couple a high

  13. Circulating angiogenic cell function is inhibited by cortisol in vitro and associated with psychological stress and cortisol in vivo.

    PubMed

    Aschbacher, Kirstin; Derakhshandeh, Ronak; Flores, Abdiel J; Narayan, Shilpa; Mendes, Wendy Berry; Springer, Matthew L

    2016-05-01

    Psychological stress and glucocorticoids are associated with heightened cardiovascular disease risk. We investigated whether stress or cortisol would be associated with reduced circulating angiogenic cell (CAC) function, an index of impaired vascular repair. We hypothesized that minority-race individuals who experience threat in interracial interactions would exhibit reduced CAC function, and that this link might be explained by cortisol. To test this experimentally, we recruited 106 African American participants for a laboratory interracial interaction task, in which they received socially evaluative feedback from Caucasian confederates. On a separate day, a subset of 32 participants (mean age=26years, 47% female) enrolled in a separate biological substudy and provided blood samples for CAC isolation and salivary samples to quantify the morning peak in cortisol (the cortisol awakening response, CAR). CAC function was quantified using cell culture assays of migration to vascular endothelial growth factor (VEGF) and secretion of VEGF into the culture medium. Heightened threat in response to an interracial interaction and trait anxiety in vivo were both associated with poorer CAC migratory function in vitro. Further, threat and poorer sustained attention during the interracial interaction were associated with a higher CAR, which in turn, was related to lower CAC sensitivity to glucocorticoids. In vitro, higher doses of cortisol impaired CAC migratory function and VEGF protein secretion. The glucocorticoid receptor antagonist RU486 reversed this functional impairment. These data identify a novel, neuroendocrine pathway by which psychological stress may reduce CAC function, with potential implications for cardiovascular health.

  14. Circulating angiogenic cell function is inhibited by cortisol in vitro and associated with psychological stress and cortisol in vivo.

    PubMed

    Aschbacher, Kirstin; Derakhshandeh, Ronak; Flores, Abdiel J; Narayan, Shilpa; Mendes, Wendy Berry; Springer, Matthew L

    2016-05-01

    Psychological stress and glucocorticoids are associated with heightened cardiovascular disease risk. We investigated whether stress or cortisol would be associated with reduced circulating angiogenic cell (CAC) function, an index of impaired vascular repair. We hypothesized that minority-race individuals who experience threat in interracial interactions would exhibit reduced CAC function, and that this link might be explained by cortisol. To test this experimentally, we recruited 106 African American participants for a laboratory interracial interaction task, in which they received socially evaluative feedback from Caucasian confederates. On a separate day, a subset of 32 participants (mean age=26years, 47% female) enrolled in a separate biological substudy and provided blood samples for CAC isolation and salivary samples to quantify the morning peak in cortisol (the cortisol awakening response, CAR). CAC function was quantified using cell culture assays of migration to vascular endothelial growth factor (VEGF) and secretion of VEGF into the culture medium. Heightened threat in response to an interracial interaction and trait anxiety in vivo were both associated with poorer CAC migratory function in vitro. Further, threat and poorer sustained attention during the interracial interaction were associated with a higher CAR, which in turn, was related to lower CAC sensitivity to glucocorticoids. In vitro, higher doses of cortisol impaired CAC migratory function and VEGF protein secretion. The glucocorticoid receptor antagonist RU486 reversed this functional impairment. These data identify a novel, neuroendocrine pathway by which psychological stress may reduce CAC function, with potential implications for cardiovascular health. PMID:26925833

  15. Mechanisms of Change: Testing how Preventative Interventions Impact Psychological and Physiological Stress Functioning in Mothers in Neglectful Families

    PubMed Central

    Toth, Sheree L.; Sturge-Apple, Melissa L.; Rogosch, Fred A.; Cicchetti, Dante

    2015-01-01

    The present study applies a multilevel approach to an examination of the effect of two randomized preventative interventions with mothers in neglectful families who are also contending with elevated levels of impoverishment and ecological risk. Specifically, we examined how participation in either Child-Parent Psychotherapy (CPP) or Psychoeducational Parenting (PPI) interventions was associated with reductions in maternal psychological parenting stress and in turn physiological stress system functioning when compared to mothers involved in standard community services (CS) as well as a demographic comparison group of nonmaltreating mothers (NC). The resulting group sizes in the current investigation were: CPP (n = 44), PPI (n = 34), CS (n = 27), and NC (n = 52). Mothers and infants who were 13-months of age were randomly assigned to intervention group at baseline. Mothers completed assessments on stress within the parenting role at baseline and post-intervention. Basal cortisol was sampled at post-intervention and 1-year follow-up. Latent difference score analyses examined change in these constructs over time. Results suggested that mothers within the CPP intervention experienced significant declines in child-related parenting stress while mothers in the PPI intervention reported declines in parent-related parenting stress. In turn, significant decreases in stress within the CPP mothers were further associated with adaptive basal cortisol functioning at 1-year post-intervention. Results highlight the value of delineating how participation in preventtive interventions aimed at ameliorating child maltreatment in neglectful families within the context of poverty may operate through improvements in psychological and physiological stress functioning. Findings are discussed with respect to the importance of multi-level assessments of intervention process and outcome. PMID:26535951

  16. Mechanisms of change: Testing how preventative interventions impact psychological and physiological stress functioning in mothers in neglectful families.

    PubMed

    Toth, Sheree L; Sturge-Apple, Melissa L; Rogosch, Fred A; Cicchetti, Dante

    2015-11-01

    The present study applies a multilevel approach to an examination of the effect of two randomized preventive interventions with mothers in neglectful families who are also contending with elevated levels of impoverishment and ecological risk. Specifically, we examined how participation in either child-parent psychotherapy (CPP) or psychoeducational parenting intervention (PPI) was associated with reductions in maternal psychological parenting stress and in turn physiological stress system functioning when compared to mothers involved in standard community services as well as a demographic comparison group of nonmaltreating mothers. The resulting group sizes in the current investigation were 44 for CPP, 34 for PPI, 27 for community services, and 52 for nonmaltreating mothers. Mothers and their 13-month-old infants were randomly assigned to intervention group at baseline. Mothers completed assessments on stress within the parenting role at baseline and postintervention. Basal cortisol was sampled at postintervention and 1-year follow-up. Latent difference score analyses examined change in these constructs over time. Results suggested that mothers within the CPP intervention experienced significant declines in child-related parenting stress, while mothers in the PPI intervention reported declines in parent-related parenting stress. In turn, significant decreases in stress within the CPP mothers were further associated with adaptive basal cortisol functioning at 1-year postintervention. The results highlight the value of delineating how participation in preventive interventions aimed at ameliorating child maltreatment in neglectful families within the context of poverty may operate through improvements in psychological and physiological stress functioning. Findings are discussed with respect to the importance of multilevel assessments of intervention process and outcome. PMID:26535951

  17. Functional analysis of atfA gene to stress response in pathogenic thermal dimorphic fungus Penicillium marneffei.

    PubMed

    Nimmanee, Panjaphorn; Woo, Patrick C Y; Vanittanakom, Pramote; Youngchim, Sirida; Vanittanakom, Nongnuch

    2014-01-01

    Penicillium marneffei, the pathogenic thermal dimorphic fungus is a causative agent of a fatal systemic disease, penicilliosis marneffei, in immunocompromised patients especially HIV patients. For growth and survival, this fungus has to adapt to environmental stresses outside and inside host cells and this adaptation requires stress signaling pathways and regulation of gene expression under various kinds of stresses. In this report, P. marneffei activating transcription factor (atfA) gene encoding bZip-type transcription factor was characterized. To determine functions of this gene, atfA isogenic mutant strain was constructed using the modified split marker recombination method. The phenotypes and susceptibility to varieties of stresses including osmotic, oxidative, heat, UV, cell wall and cell membrane stresses of the mutant strain were compared with the wild type and the atfA complemented strains. Results demonstrated that the mRNA expression level of P. marneffei atfA gene increased under heat stress at 42°C. The atfA mutant was more sensitive to sodium dodecyl sulphate, amphotericin B and tert-butyl hydroperoxide than the wild type and complemented strains but not hydrogen peroxide, menadione, NaCl, sorbitol, calcofluor white, itraconazole, UV stresses and heat stress at 39°C. In addition, recovery of atfA mutant conidia after mouse and human macrophage infections was significantly decreased compared to those of wild type and complemented strains. These results indicated that the atfA gene was required by P. marneffei under specific stress conditions and might be necessary for fighting against host immune cells during the initiation of infection.

  18. Functional analysis of atfA gene to stress response in pathogenic thermal dimorphic fungus Penicillium marneffei.

    PubMed

    Nimmanee, Panjaphorn; Woo, Patrick C Y; Vanittanakom, Pramote; Youngchim, Sirida; Vanittanakom, Nongnuch

    2014-01-01

    Penicillium marneffei, the pathogenic thermal dimorphic fungus is a causative agent of a fatal systemic disease, penicilliosis marneffei, in immunocompromised patients especially HIV patients. For growth and survival, this fungus has to adapt to environmental stresses outside and inside host cells and this adaptation requires stress signaling pathways and regulation of gene expression under various kinds of stresses. In this report, P. marneffei activating transcription factor (atfA) gene encoding bZip-type transcription factor was characterized. To determine functions of this gene, atfA isogenic mutant strain was constructed using the modified split marker recombination method. The phenotypes and susceptibility to varieties of stresses including osmotic, oxidative, heat, UV, cell wall and cell membrane stresses of the mutant strain were compared with the wild type and the atfA complemented strains. Results demonstrated that the mRNA expression level of P. marneffei atfA gene increased under heat stress at 42°C. The atfA mutant was more sensitive to sodium dodecyl sulphate, amphotericin B and tert-butyl hydroperoxide than the wild type and complemented strains but not hydrogen peroxide, menadione, NaCl, sorbitol, calcofluor white, itraconazole, UV stresses and heat stress at 39°C. In addition, recovery of atfA mutant conidia after mouse and human macrophage infections was significantly decreased compared to those of wild type and complemented strains. These results indicated that the atfA gene was required by P. marneffei under specific stress conditions and might be necessary for fighting against host immune cells during the initiation of infection. PMID:25365258

  19. Brown seaweed- (Tasco) treated conserved forage enhances antioxidant status and immune function in heat-stressed wether lambs.

    PubMed

    Saker, K E; Fike, J H; Veit, H; Ward, D L

    2004-04-01

    Twenty-seven wether lambs were utilized to evaluate select innate immunity and oxidative stress in response to diet and heat stress. Dietary treatments were: (i) control (tall fescue) hay = no Tasco (tradename for the extract of the brown seaweed, Ascophyllum nodosum, Acadian Sealants Ltd, Nova Scotia, Canada); (ii) pre-harvest Tasco-Forage-treated hay and (iii) control hay + post-harvest Tasco-EX. Tasco-Forage and Tasco-EX are two forms of the Tasco extract that are either applied to foliage or used for direct feeding, respectively. All lambs were supplemented with soyabean meal and trace mineralized salt. Heat stress was applied for 10 days with measurements obtained at days 0, 4 and 10. A heat x treatment interaction indicated hay with Tasco enhanced monocyte oxidative burst through short duration (p < 0.05) and long duration (p < 0.10) heat stress. Phagocytic activity was influenced by days of heat stress (p < 0.001) and treatment (p = 0.02) with post-harvest Tasco lambs exhibiting the greatest immune enhancement (p < 0.05). Red and white blood cell glutathione peroxidase increased by heat stress day 10 in Tasco lambs. Superoxide dismutase activity was increased and lipid hydroperoxide metabolites minimized (p < 0.01) through long duration heat stress in the pre-harvest Tasco group. Tasco treatment of tall fescue hay prior to harvest appears to provide residual effects on animal antioxidant availability in short-duration heat stress. Tasco supplementation to post-harvest fescue hay enhances immune function and protects against prolonged heat-induced oxidative stress.

  20. Exercise, Diet, and Stress Management as Mediators between Functional Disability and Health-Related Quality of Life in Multiple Sclerosis

    ERIC Educational Resources Information Center

    Sung, Connie; Chiu, Chung-Yi; Lee, Eun-Jeong; Bezyak, Jill; Chan, Fong; Muller, Veronica

    2013-01-01

    The main objective of this study was to examine the mediational and moderational effect of exercise, diet, and stress management on the relationship between functional disability and health-related quality of life. Quantitative descriptive research design using multiple regression and correlation techniques was used. Participants were 215…

  1. Posttraumatic Stress Disorder Symptom Structure in Injured Children: Functional Impairment and Depression Symptoms in a Confirmatory Factor Analysis

    ERIC Educational Resources Information Center

    Kassam-Adams, Nancy; Marsac, Meghan L.; Cirilli, Carla

    2010-01-01

    Objective: To examine the factor structure of posttraumatic stress disorder (PTSD) symptoms in children and adolescents who have experienced an acute single-incident trauma, associations between PTSD symptom clusters and functional impairment, and the specificity of PTSD symptoms in relation to depression and general distress. Method: Examined…

  2. Virial theorem for an inhomogeneous medium, boundary conditions for the wave functions, and stress tensor in quantum statistics.

    PubMed

    Bobrov, V B; Trigger, S A; van Heijst, G J F; Schram, P P J M

    2010-07-01

    On the basis of the stationary Schrödinger equation, the virial theorem in an inhomogeneous external field for the canonical ensemble is proved. It is shown that the difference in the form of virial theorem is conditioned by the value of the wave-function derivative on the surface of the volume, surrounding the system under consideration. The stress tensor in such a system is determined by the average values of the wave-function space derivatives.

  3. Virial theorem for an inhomogeneous medium, boundary conditions for the wave functions, and stress tensor in quantum statistics.

    PubMed

    Bobrov, V B; Trigger, S A; van Heijst, G J F; Schram, P P J M

    2010-07-01

    On the basis of the stationary Schrödinger equation, the virial theorem in an inhomogeneous external field for the canonical ensemble is proved. It is shown that the difference in the form of virial theorem is conditioned by the value of the wave-function derivative on the surface of the volume, surrounding the system under consideration. The stress tensor in such a system is determined by the average values of the wave-function space derivatives. PMID:20866550

  4. Effects of childhood poverty and chronic stress on emotion regulatory brain function in adulthood.

    PubMed

    Kim, Pilyoung; Evans, Gary W; Angstadt, Michael; Ho, S Shaun; Sripada, Chandra S; Swain, James E; Liberzon, Israel; Phan, K Luan

    2013-11-12

    Childhood poverty has pervasive negative physical and psychological health sequelae in adulthood. Exposure to chronic stressors may be one underlying mechanism for childhood poverty-health relations by influencing emotion regulatory systems. Animal work and human cross-sectional studies both suggest that chronic stressor exposure is associated with amygdala and prefrontal cortex regions important for emotion regulation. In this longitudinal functional magnetic resonance imaging study of 49 participants, we examined associations between childhood poverty at age 9 and adult neural circuitry activation during emotion regulation at age 24. To test developmental timing, concurrent, adult income was included as a covariate. Adults with lower family income at age 9 exhibited reduced ventrolateral and dorsolateral prefrontal cortex activity and failure to suppress amygdala activation during effortful regulation of negative emotion at age 24. In contrast to childhood income, concurrent adult income was not associated with neural activity during emotion regulation. Furthermore, chronic stressor exposure across childhood (at age 9, 13, and 17) mediated the relations between family income at age 9 and ventrolateral and dorsolateral prefrontal cortex activity at age 24. The findings demonstrate the significance of childhood chronic stress exposures in predicting neural outcomes during emotion regulation in adults who grew up in poverty.

  5. Survival of starving yeast is correlated with oxidative stress response and nonrespiratory mitochondrial function.

    PubMed

    Petti, Allegra A; Crutchfield, Christopher A; Rabinowitz, Joshua D; Botstein, David

    2011-11-01

    Survival of yeast during starvation has been shown to depend on the nature of the missing nutrient(s). In general, starvation for "natural" nutrients such as sources of carbon, phosphate, nitrogen, or sulfate results in low death rates, whereas starvation for amino acids or other metabolites in auxotrophic mutants results in rapid loss of viability. Here we characterized phenotype, gene expression, and metabolite abundance during starvation for methionine. Some methionine auxotrophs (those with blocks in the biosynthetic pathway) respond to methionine starvation like yeast starving for natural nutrients such as phosphate or sulfate: they undergo a uniform cell cycle arrest, conserve glucose, and survive. In contrast, methionine auxotrophs with defects in the transcription factors Met31p and Met32p respond poorly, like other auxotrophs. We combined physiological and gene expression data from a variety of nutrient starvations (in both respiratory competent and incompetent cells) to show that successful starvation response is correlated with expression of genes encoding oxidative stress response and nonrespiratory mitochondrial functions, but not respiration per se.

  6. Low oxygen alters mitochondrial function and response to oxidative stress in human neural progenitor cells.

    PubMed

    Lages, Yury M; Nascimento, Juliana M; Lemos, Gabriela A; Galina, Antonio; Castilho, Leda R; Rehen, Stevens K

    2015-01-01

    Oxygen concentration should be carefully regulated in all living tissues, beginning at the early embryonic stages. Unbalances in oxygen regulation can lead to cell death and disease. However, to date, few studies have investigated the consequences of variations in oxygen levels for fetal-like cells. Therefore, in the present work, human neural progenitor cells (NPCs) derived from pluripotent stem cells grown in 3% oxygen (v/v) were compared with NPCs cultured in 21% (v/v) oxygen. Low oxygen concentrations altered the mitochondrial content and oxidative functions of the cells, which led to improved ATP production, while reducing generation of reactive oxygen species (ROS). NPCs cultured in both conditions showed no differences in proliferation and glucose metabolism. Furthermore, antioxidant enzymatic activity was not altered in NPCs cultured in 3% oxygen under normal conditions, however, when exposed to external agents known to induce oxidative stress, greater susceptibility to DNA damage was observed. Our findings indicate that the management of oxygen levels should be considered for in vitro models of neuronal development and drug screening.

  7. Catalase function in plants: a focus on Arabidopsis mutants as stress-mimic models.

    PubMed

    Mhamdi, Amna; Queval, Guillaume; Chaouch, Sejir; Vanderauwera, Sandy; Van Breusegem, Frank; Noctor, Graham

    2010-10-01

    Hydrogen peroxide (H(2)O(2)) is an important signal molecule involved in plant development and environmental responses. Changes in H(2)O(2) availability can result from increased production or decreased metabolism. While plants contain several types of H(2)O(2)-metabolizing proteins, catalases are highly active enzymes that do not require cellular reductants as they primarily catalyse a dismutase reaction. This review provides an update on plant catalase genes, function, and subcellular localization, with a focus on recent information generated from studies on Arabidopsis. Original data are presented on Arabidopsis catalase single and double mutants, and the use of some of these lines as model systems to investigate the outcome of increases in intracellular H(2)O(2) are discussed. Particular attention is paid to interactions with cell thiol-disulphide status; the use of catalase-deficient plants to probe the apparent redundancy of reductive H(2)O(2)-metabolizing pathways; the importance of irradiance and growth daylength in determining the outcomes of catalase deficiency; and the induction of pathogenesis-related responses in catalase-deficient lines. Within the context of strategies aimed at understanding and engineering plant stress responses, the review also considers whether changes in catalase activities in wild-type plants are likely to be a significant part of plant responses to changes in environmental conditions or biotic challenge.

  8. IFNα/βR Signaling Promotes Regulatory T Cell Development and Function Under Stress Conditions

    PubMed Central

    Metidji, Amina; Rieder, Sadiye Amcaoglu; Glass, Deborah Dacek; Cremer, Isabelle; Punkosdy, George A.; Shevach, Ethan M.

    2015-01-01

    Type I IFNs are a family of cytokines with antiviral and immunomodulatory properties. While the antiviral effects of IFNs are well characterized, their immunomodulatory properties are less clear. To specifically address the effects of type I IFNs on Treg, we studied mixed bone morrow (BM) chimeras between wild-type (WT) and IFNα/βR (IFNAR) knockout (KO) mice, and heterozygous female mice expressing a Treg-specific deletion of the IFNAR. In these two models, IFNAR signaling promotes the development of the Treg lineage in the thymus and their survival in the periphery. IFNAR KO Treg had a higher expression of the pro-apoptotic gene Bim and higher frequency of active caspase positive cells. IFNAR KO Treg from chimeric mice displayed a more naïve phenotype, accompanied by lower levels of CD25 and phosphorylated STAT5. Therefore, in Treg IFNAR signaling may directly or indirectly affect phosphorylation of STAT5. In mixed chimeras with Scurfy fetal liver, Treg derived from IFNAR KO BM were unable to control T effector cell activation and tissue inflammation. Under stress conditions or in a competitive environment, IFNAR signaling may be required to maintain Treg homeostasis and function. PMID:25795758

  9. Cardiovascular response of individuals with spinal cord injury to dynamic functional electrical stimulation under orthostatic stress.

    PubMed

    Yoshida, Takashi; Masani, Kei; Sayenko, Dimitry G; Miyatani, Masae; Fisher, Joseph A; Popovic, Milos R

    2013-01-01

    In this pilot study, we examined how effectively functional electrical stimulation (FES) and passive stepping mitigated orthostatic hypotension in participants with chronic spinal cord injury (SCI). While being tilted head-up to 70 (°) from the supine position, the participants underwent four 10-min conditions in a random sequence: 1) no intervention, 2) passive stepping, 3) isometric FES of leg muscles, and 4) FES of leg muscles combined with passive stepping. We found that FES and passive stepping independently mitigated a decrease in stroke volume and helped to maintain the mean blood pressure. The effects of FES on stroke volume and mean blood pressure were greater than those of passive stepping. When combined, FES and passive stepping did not interfere with each other, but they also did not synergistically increase stroke volume or mean blood pressure. Thus, the present study suggests that FES delivered to lower limbs can be used in individuals with SCI to help them withstand orthostatic stress. Additional studies are needed to confirm whether this use of FES is applicable to a larger population of individuals with SCI.

  10. The exon-junction-complex-component metastatic lymph node 51 functions in stress-granule assembly.

    PubMed

    Baguet, Aurélie; Degot, Sébastien; Cougot, Nicolas; Bertrand, Edouard; Chenard, Marie-Pierre; Wendling, Corinne; Kessler, Pascal; Le Hir, Hervé; Rio, Marie-Christine; Tomasetto, Catherine

    2007-08-15

    Metastatic lymph node 51 [MLN51 (also known as CASC3)] is a component of the exon junction complex (EJC), which is assembled on spliced mRNAs and plays important roles in post-splicing events. The four proteins of the EJC core, MLN51, MAGOH, Y14 and EIF4AIII shuttle between the cytoplasm and the nucleus. However, unlike the last three, MLN51 is mainly detected in the cytoplasm, suggesting that it plays an additional function in this compartment. In the present study, we show that MLN51 is recruited into cytoplasmic aggregates known as stress granules (SGs) together with the SG-resident proteins, fragile X mental retardation protein (FMRP), poly(A) binding protein (PABP) and poly(A)(+) RNA. MLN51 specifically associates with SGs via its C-terminal region, which is dispensable for its incorporation in the EJC. MLN51 does not promote SG formation but its silencing, or the overexpression of a mutant lacking its C-terminal region, alters SG assembly. Finally, in human breast carcinomas, MLN51 is sometimes present in cytoplasmic foci also positive for FMRP and PABP, suggesting that SGs formation occurs in malignant tumours.

  11. A First Line of Stress Defense: Small Heat Shock Proteins and their function in protein homeostasis

    PubMed Central

    Haslbeck, Martin; Vierling, Elizabeth

    2015-01-01

    Small heat shock proteins (sHsps) are virtually ubiquitous molecular chaperones that can prevent the irreversible aggregation of denaturing proteins. To maintain protein homeostasis, sHsps complex with a variety of nonnative proteins in an ATP-independent manner and, in the context of the stress response, form a first line of defense against protein aggregation. In vertebrates they act to maintain the clarity of the eye lens, and in humans sHsp mutations are linked to myopathies and neuropathies. Although found in all domains of life, sHsps are quite diverse and have evolved independently in metazoans, plants and fungi. sHsp monomers range in size from approximately 12 to 42 kDa and are defined by a conserved β-sandwich α-crystallin domain, flanked by variable N- and C-terminal sequences. Most sHsps form large oligomeric ensembles with a broad distribution of different, sphere- or barrel like oligomers, with the size and structure of the oligomers dictated by features of the N- and C-termini. The activity of sHsps is regulated by mechanisms that change the equilibrium distribution in tertiary features and/or quaternary structure of the sHsp ensembles. Cooperation and/or coassembly between different sHsps in the same cellular compartment adds an underexplored level of complexity to sHsp structure and function. PMID:25681016

  12. Interconnection of tectonic stresses in the Earth's crust and dynamics of the groundwater basin functioning

    NASA Astrophysics Data System (ADS)

    Koneshov, Vycheslav; Trifonova, Tatiana; Trifonov, Dmitriy; Arakelian, Sergey

    2016-04-01

    1. Possible influence of tectonic stresses on the occurrence of catastrophic floods by the mechanism of modification of the 3D-cracknet of the rock formations and the transit of the groundwater in this natural transport system in the conditions of functioning of the river catchment basin is discussed. Several floods (not freshets) took place in 2013-2014, which probably could be associated with corresponding seismic processes in the Earth's crust, are considered. 2. A river basin formation in the mountain slope can be considered as a self-organizing staged process of its evolution passing through several non-equilibrium but steady-state conditions. The controlling parameter is the process of the crack spreading out. Crack development up the slope but downward substance transit, stipulates a feedback within the unified 3D-river basin system. 3. We have briefly described and rendered the mechanism of the influence of seismic activity on the occurrence of concrete floods with the use of combined maps of groundwater resources and the boundaries of lithospheric plates on the territory and the revealed regularities in seismic waves propagation and interaction with groundwater. 4. In the practical aspect a proposed hypothesis can be useful during the definition of potentially dangerous areas for catastrophic water events taking into account the interference of the state of the underground hydrosphere and the tectonic structure of the rheological section of bowels of the earth on the concrete territories under some adjustable (seismic) conditions.

  13. A first line of stress defense: small heat shock proteins and their function in protein homeostasis.

    PubMed

    Haslbeck, Martin; Vierling, Elizabeth

    2015-04-10

    Small heat shock proteins (sHsps) are virtually ubiquitous molecular chaperones that can prevent the irreversible aggregation of denaturing proteins. sHsps complex with a variety of non-native proteins in an ATP-independent manner and, in the context of the stress response, form a first line of defense against protein aggregation in order to maintain protein homeostasis. In vertebrates, they act to maintain the clarity of the eye lens, and in humans, sHsp mutations are linked to myopathies and neuropathies. Although found in all domains of life, sHsps are quite diverse and have evolved independently in metazoans, plants and fungi. sHsp monomers range in size from approximately 12 to 42kDa and are defined by a conserved β-sandwich α-crystallin domain, flanked by variable N- and C-terminal sequences. Most sHsps form large oligomeric ensembles with a broad distribution of different, sphere- or barrel-like oligomers, with the size and structure of the oligomers dictated by features of the N- and C-termini. The activity of sHsps is regulated by mechanisms that change the equilibrium distribution in tertiary features and/or quaternary structure of the sHsp ensembles. Cooperation and/or co-assembly between different sHsps in the same cellular compartment add an underexplored level of complexity to sHsp structure and function.

  14. Residual stress and fracture characteristics of zirconia/metal(Ni, SUS304) functionally gradient materials

    SciTech Connect

    Jung, Yeon-Gil; Choi, Sung-Churl; Paik, Un-Gyu

    1995-09-01

    To analyze the residual stress and the fracture behavior of FGMs. disc-type TZP/Ni- and TZP/SUS304-FGM were hot passed, and compared with MM& The continuous interface and the microstructure of FGMs were characterized with EPMA, optical microscopy and SEM. The defect-like cracks in the FGMs induced by the preferential shear stress have been shown to cause fracture. This fact has well corresponded to the analysis of the residual stress distribution by FEM.

  15. Toward Coalescing Gene Expression and Function with QTLs of Water-Deficit Stress in Cotton.

    PubMed

    Kebede, Hirut; Payton, Paxton; Pham, Hanh Thi My; Allen, Randy D; Wright, Robert J

    2015-01-01

    Cotton exhibits moderately high vegetative tolerance to water-deficit stress but lint production is restricted by the available rainfed and irrigation capacity. We have described the impact of water-deficit stress on the genetic and metabolic control of fiber quality and production. Here we examine the association of tentative consensus sequences (TCs) derived from various cotton tissues under irrigated and water-limited conditions with stress-responsive QTLs. Three thousand sixteen mapped sequence-tagged-sites were used as anchored targets to examine sequence homology with 15,784 TCs to test the hypothesis that putative stress-responsive genes will map within QTLs associated with stress-related phenotypic variation more frequently than with other genomic regions not associated with these QTLs. Approximately 1,906 of 15,784 TCs were mapped to the consensus map. About 35% of the annotated TCs that mapped within QTL regions were genes involved in an abiotic stress response. By comparison, only 14.5% of the annotated TCs mapped outside these QTLs were classified as abiotic stress genes. A simple binomial probability calculation of this degree of bias being observed if QTL and non-QTL regions are equally likely to contain stress genes was P (x ≥ 85) = 7.99  × 10(-15). These results suggest that the QTL regions have a higher propensity to contain stress genes. PMID:26167172

  16. CsPAO4 of Citrus sinensis functions in polyamine terminal catabolism and inhibits plant growth under salt stress

    PubMed Central

    Wang, Wei; Liu, Ji-Hong

    2016-01-01

    Polyamine oxidase (PAO) is a key enzyme catalyzing polyamine catabolism leading to H2O2 production. We previously demonstrated that Citrus sinensis contains six putative PAO genes, but their functions are not well understood. In this work, we reported functional elucidation of CsPAO4 in polyamine catabolism and salt