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Sample records for structural plasticity play

  1. Playing Super Mario induces structural brain plasticity: gray matter changes resulting from training with a commercial video game.

    Science.gov (United States)

    Kühn, S; Gleich, T; Lorenz, R C; Lindenberger, U; Gallinat, J

    2014-02-01

    Video gaming is a highly pervasive activity, providing a multitude of complex cognitive and motor demands. Gaming can be seen as an intense training of several skills. Associated cerebral structural plasticity induced has not been investigated so far. Comparing a control with a video gaming training group that was trained for 2 months for at least 30 min per day with a platformer game, we found significant gray matter (GM) increase in right hippocampal formation (HC), right dorsolateral prefrontal cortex (DLPFC) and bilateral cerebellum in the training group. The HC increase correlated with changes from egocentric to allocentric navigation strategy. GM increases in HC and DLPFC correlated with participants' desire for video gaming, evidence suggesting a predictive role of desire in volume change. Video game training augments GM in brain areas crucial for spatial navigation, strategic planning, working memory and motor performance going along with evidence for behavioral changes of navigation strategy. The presented video game training could therefore be used to counteract known risk factors for mental disease such as smaller hippocampus and prefrontal cortex volume in, for example, post-traumatic stress disorder, schizophrenia and neurodegenerative disease.

  2. PLASTIC ANALYSIS OF STEEL FRAME STRUCTURE

    Directory of Open Access Journals (Sweden)

    M. Rogac

    2013-05-01

    Full Text Available This paper presents the plastic analysis of steel frame structure loaded by gravity loads. By applying the cinematic theorem of ultimate analysis, the ultimate load for the case of elastic - ideally plastic material is calculated. The identical structure was treated in the computer program SAP2000 where the zone of material reinforcement in the plastic area was covered. Keywords: Steel frame structure, plastic analysis, ultimate gravity load, material reinforcement.

  3. Psychedelics Promote Structural and Functional Neural Plasticity

    Directory of Open Access Journals (Sweden)

    Calvin Ly

    2018-06-01

    Full Text Available Summary: Atrophy of neurons in the prefrontal cortex (PFC plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders. : Ly et al. demonstrate that psychedelic compounds such as LSD, DMT, and DOI increase dendritic arbor complexity, promote dendritic spine growth, and stimulate synapse formation. These cellular effects are similar to those produced by the fast-acting antidepressant ketamine and highlight the potential of psychedelics for treating depression and related disorders. Keywords: neural plasticity, psychedelic, spinogenesis, synaptogenesis, depression, LSD, DMT, ketamine, noribogaine, MDMA

  4. Plastic

    International Nuclear Information System (INIS)

    Jeong Gi Hyeon

    1987-04-01

    This book deals with plastic, which includes introduction for plastic, chemistry of high polymers, polymerization, speciality and structure of a high molecule property of plastic, molding, thermosetting plastic, such as polyethylene, polyether, polyamide and polyvinyl acetyl, thermal plastic like phenolic resins, xylene resins, melamine resin, epoxy resin, alkyd resin and poly urethan resin, new plastic like ionomer and PPS resin, synthetic laminated tape and synthetic wood, mixed materials in plastic, reprocessing of waste plastic, polymer blend, test method for plastic materials and auxiliary materials of plastic.

  5. Psychedelics Promote Structural and Functional Neural Plasticity.

    Science.gov (United States)

    Ly, Calvin; Greb, Alexandra C; Cameron, Lindsay P; Wong, Jonathan M; Barragan, Eden V; Wilson, Paige C; Burbach, Kyle F; Soltanzadeh Zarandi, Sina; Sood, Alexander; Paddy, Michael R; Duim, Whitney C; Dennis, Megan Y; McAllister, A Kimberley; Ori-McKenney, Kassandra M; Gray, John A; Olson, David E

    2018-06-12

    Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  6. Reliability of Elasto-Plastic Structural Systems

    DEFF Research Database (Denmark)

    Delmar, M. V.; Sørensen, John Dalsgaard

    1990-01-01

    This paper proposes a method for generating safety margins and failure mode equations for elasto-plastic structures where interaction of load effects is taken into account. Structural failure is defined by large nodal displacements or plastic collapse. A branch-and-bound technique is used...

  7. Brain structural plasticity with spaceflight

    OpenAIRE

    Koppelmans, Vincent; Bloomberg, Jacob J; Mulavara, Ajitkumar P; Seidler, Rachael D

    2016-01-01

    Humans undergo extensive sensorimotor adaptation during spaceflight due to altered vestibular inputs and body unloading. No studies have yet evaluated the effects of spaceflight on human brain structure despite the fact that recently reported optic nerve structural changes are hypothesized to occur due to increased intracranial pressure occurring with microgravity. This is the first report on human brain structural changes with spaceflight. We evaluated retrospective longitudinal T2-weighted ...

  8. Sleep loss and structural plasticity.

    Science.gov (United States)

    Areal, Cassandra C; Warby, Simon C; Mongrain, Valérie

    2017-06-01

    Wakefulness and sleep are dynamic states during which brain functioning is modified and shaped. Sleep loss is detrimental to many brain functions and results in structural changes localized at synapses in the nervous system. In this review, we present and discuss some of the latest observations of structural changes following sleep loss in some vertebrates and insects. We also emphasize that these changes are region-specific and cell type-specific and that, most importantly, these structural modifications have functional roles in sleep regulation and brain functions. Selected mechanisms driving structural modifications occurring with sleep loss are also discussed. Overall, recent research highlights that extending wakefulness impacts synapse number and shape, which in turn regulate sleep need and sleep-dependent learning/memory. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Brain structural plasticity with spaceflight.

    Science.gov (United States)

    Koppelmans, Vincent; Bloomberg, Jacob J; Mulavara, Ajitkumar P; Seidler, Rachael D

    2016-01-01

    Humans undergo extensive sensorimotor adaptation during spaceflight due to altered vestibular inputs and body unloading. No studies have yet evaluated the effects of spaceflight on human brain structure despite the fact that recently reported optic nerve structural changes are hypothesized to occur due to increased intracranial pressure occurring with microgravity. This is the first report on human brain structural changes with spaceflight. We evaluated retrospective longitudinal T2-weighted MRI scans and balance data from 27 astronauts (thirteen ~2-week shuttle crew members and fourteen ~6-month International Space Station crew members) to determine spaceflight effects on brain structure, and whether any pre to postflight brain changes are associated with balance changes. Data were obtained from the NASA Lifetime Surveillance of Astronaut Health. Brain scans were segmented into gray matter maps and normalized into MNI space using a stepwise approach through subject specific templates. Non-parametric permutation testing was used to analyze pre to postflight volumetric gray matter changes. We found extensive volumetric gray matter decreases, including large areas covering the temporal and frontal poles and around the orbits. This effect was larger in International Space Station versus shuttle crew members in some regions. There were bilateral focal gray matter increases within the medial primary somatosensory and motor cortex; i.e., the cerebral areas where the lower limbs are represented. These intriguing findings are observed in a retrospective data set; future prospective studies should probe the underlying mechanisms and behavioral consequences.

  10. [Structural plasticity associated with drugs addiction].

    Science.gov (United States)

    Zhu, Jie; Cao, Guo-fen; Dang, Yong-hui; Chen, Teng

    2011-12-01

    An essential feature of drug addiction is that an individual continues to use drug despite the threat of severely adverse physical or psychosocial consequences. Persistent changes in behavior and psychological function that occur as a function of drugs of abuse are thought to be due to the reorganization of synaptic connections (structural plasticity) in relevant brain circuits (especially the brains reward circuits). In this paper we summarized evidence that, indeed, exposure to amphetamine, cocaine, nicotine or morphine produced persistent changes in the structure of dendrites and dendritic spines on cells in relevant brain regions. We also approached the potential molecular mechanisms of these changes. It is suggested that structural plasticity associated with exposure to drugs of abuse reflects a reorganization of patterns of synaptic connectivity in these neural systems, a reorganization that alters their operation, thus contributing to some of the persistent sequela associated with drug use-including addiction.

  11. Global plastic models for computerized structural analysis

    International Nuclear Information System (INIS)

    Roche, R.L.; Hoffmann, A.

    1977-01-01

    In many types of structures, it is possible to use generalized stresses (like membrane forces, bending moment, torsion moment...) to define a yield surface for a part of the structure. Analysis can be achieved by using the HILL's principle and a hardening rule. The whole formulation is said 'Global Plastic Model'. Two different global models are used in the CEASEMT system for structural analysis, one for shell analysis and the other for piping analysis (in plastic or creep field). In shell analysis the generalized stresses chosen are the membrane forces and bending (including torsion) moments. There is only one yield condition for a normal to the middle surface and no integration along the thickness is required. In piping analysis, the choice of generalized stresses is bending moments, torsional moment, hoop stress and tension stress. There is only a set of stresses for a cross section and no integration over the cross section area is needed. Connected strains are axis curvature, torsion, uniform strains. The definition of the yield surface is the most important item. A practical way is to use a diagonal quadratic function of the stress components. But the coefficients are depending of the shape of the pipe element, especially for curved segments. Indications will be given on the yield functions used. Some examples of applications in structural analysis are added to the text

  12. The effects of hormones and physical exercise on hippocampal structural plasticity.

    Science.gov (United States)

    Triviño-Paredes, Juan; Patten, Anna R; Gil-Mohapel, Joana; Christie, Brian R

    2016-04-01

    The hippocampus plays an integral role in certain aspects of cognition. Hippocampal structural plasticity and in particular adult hippocampal neurogenesis can be influenced by several intrinsic and extrinsic factors. Here we review how hormones (i.e., intrinsic modulators) and physical exercise (i.e., an extrinsic modulator) can differentially modulate hippocampal plasticity in general and adult hippocampal neurogenesis in particular. Specifically, we provide an overview of the effects of sex hormones, stress hormones, and metabolic hormones on hippocampal structural plasticity and adult hippocampal neurogenesis. In addition, we also discuss how physical exercise modulates these forms of hippocampal plasticity, giving particular emphasis on how this modulation can be affected by variables such as exercise regime, duration, and intensity. Understanding the neurobiological mechanisms underlying the modulation of hippocampal structural plasticity by intrinsic and extrinsic factors will impact the design of new therapeutic approaches aimed at restoring hippocampal plasticity following brain injury or neurodegeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Plasmonic Structural Colors for Plastic Consumer Products

    DEFF Research Database (Denmark)

    Højlund-Nielsen, Emil; Mortensen, N. Asger; Kristensen, Anders

    2014-01-01

    Today colorants, such as pigments or dyes, are used to color plastic-based consumer products, either as base for solid colored bulk polymer or in inks for surface decoration. After usage, the products must be mechanically sorted by color before recycling, limiting any large-scale efficient...... can be avoided in the recycling state. Plasmon color technology based on aluminum has recently been firmly established as a route towards structural coloring of polymeric materials. We report on the fabrication of colors by localized surface plasmon resonances (LSPR) using roll-to-roll printing...

  14. Filopodia: A Rapid Structural Plasticity Substrate for Fast Learning

    Directory of Open Access Journals (Sweden)

    Ahmet S. Ozcan

    2017-06-01

    Full Text Available Formation of new synapses between neurons is an essential mechanism for learning and encoding memories. The vast majority of excitatory synapses occur on dendritic spines, therefore, the growth dynamics of spines is strongly related to the plasticity timescales. Especially in the early stages of the developing brain, there is an abundant number of long, thin and motile protrusions (i.e., filopodia, which develop in timescales of seconds and minutes. Because of their unique morphology and motility, it has been suggested that filopodia can have a dual role in both spinogenesis and environmental sampling of potential axonal partners. I propose that filopodia can lower the threshold and reduce the time to form new dendritic spines and synapses, providing a substrate for fast learning. Based on this proposition, the functional role of filopodia during brain development is discussed in relation to learning and memory. Specifically, it is hypothesized that the postnatal brain starts with a single-stage memory system with filopodia playing a significant role in rapid structural plasticity along with the stability provided by the mushroom-shaped spines. Following the maturation of the hippocampus, this highly-plastic unitary system transitions to a two-stage memory system, which consists of a plastic temporary store and a long-term stable store. In alignment with these architectural changes, it is posited that after brain maturation, filopodia-based structural plasticity will be preserved in specific areas, which are involved in fast learning (e.g., hippocampus in relation to episodic memory. These propositions aim to introduce a unifying framework for a diversity of phenomena in the brain such as synaptogenesis, pruning and memory consolidation.

  15. Playing life away: Videogames and personality structure.

    Directory of Open Access Journals (Sweden)

    Leones do Couto G.

    2014-09-01

    Full Text Available This study aims to fill a gap in the current research on the personality organization of frequent videogame users. The scientific literature in this area refers only to the existence of risk factors that increase the likelihood of abusing videogames and their negative consequences on the mental health of users (Gentile et al., 2011; Lemmens, Valkenburg, & Peter, 2011; Rehbein & Baier, 2013. In this study, a sample of patients who reported spending an excessive amount of their time playing videogames were recruited from Instituto Quintino Aires–Lisbon/Oporto and took the Rorschach Personality Test (Exner, 1993, 1995. Two other samples—one consisting of patients who reported not playing videogames, and the other of patients who were discharged from the institution after psychotherapy—also took part in the study. The patients in the first sample revealed less exposure to the relational sources of stress that are necessary for socioemotional development and less interest in others than did patients in the other samples. Other results regarding the personality structure of the subjects in the three samples are compared and discussed in light of cultural-historical psychology.

  16. Molecular motion and structure in plastics

    International Nuclear Information System (INIS)

    Doolan, K.R.; Baxter, M.

    2000-01-01

    Full text: When molten thermoplastics solidify, the polymeric chains form a completely amorphous structure or a mixture of crystalline and amorphous regions. Measurement of Nuclear Magnetic Resonance (NMR) relaxation times provides information about the configuration and molecular motion of polymeric chains in solid plastics. We are currently measuring the NMR relaxation times T 1 , T 2 , T 2 and T 1p as a function of temperature using a Bruker High Power pulsed NMR Spectrometer for several different classes of thermoplastics containing varying concentrations of inorganic filler materials. We present data here for T 1 , and T 2 obtained for polyethylenes, polypropylenes, polystyrenes and acrylics in the temperature range 100 K to 450 K. At temperatures below 320 K, all of the polyethylenes and polypropylenes and some of the polystyrenes and acrylics produced NMR signals after a single radio frequency (RF) pulse with rapidly and slowly decaying components corresponding to the rigid and flexible regions within the plastic. From these results we have estimated using Mathematica the amount of crystallinity within the polyethylenes and polypropylenes. For the impact modified polystyrenes and acrylics studied we have estimated the amounts of elastomeric phases present. We find that the initial rapid decay signal produced by polyethylenes and polypropylenes is Gaussian while the long tail is Lorentzian. All of the signal components from the polystyrenes and the acrylics were fitted using Lorentzian functions indicating their structures are highly amorphous. Addition of CaCO 3 filler to polypropylene resins appears to reduce the crystallinity of the material. We also present data for the activation energy of the molecular motion inducing longitudinal relaxation, from T 1 measurements

  17. Structural Plasticity Denoises Responses and Improves Learning Speed

    Directory of Open Access Journals (Sweden)

    Robin Spiess

    2016-09-01

    Full Text Available Despite an abundance of computational models for learning of synaptic weights, there has been relatively little research on structural plasticity, i.e. the creation and elimination of synapses. Especially, it is not clear how structural plasticity works in concert with spike-timing-dependent plasticity (STDP and what advantages their combination offers.Here we present a fairly large-scale functional model that uses leaky integrate-and-fire neurons, STDP, homeostasis, recurrent connections, and structural plasticity to learn the input encoding, the relation between inputs, and to infer missing inputs. Using this model, we compare the error and the amount of noise in the network's responses with and without structural plasticity and the influence of structural plasticity on the learning speed of the network.Using structural plasticity during learning shows good results for learning the representation of input values, i.e. structural plasticity strongly reduces the noise of the response by preventing spikes with a high error.For inferring missing inputs we see similar results, with responses having less noise if the network was trained using structural plasticity.Additionally, using structural plasticity with pruning significantly decreased the time to learn weights suitable for inference.Presumably, this is due to the clearer signal containing less spikes that misrepresent the desired value. Therefore, this work shows that structural plasticity is not only able to improve upon the performance using STDP without structural plasticity but also speeds up learning.Additionally, it addresses the practical problem of limited resources for connectivity that is not only apparent in the mammalian neocortex but also in computer hardware or neuromorphic (brain-inspired hardware by efficiently pruning synapses without losing performance.

  18. Extracellular proteolysis in structural and functional plasticity of mossy fiber synapses in hippocampus

    Directory of Open Access Journals (Sweden)

    Grzegorz eWiera

    2015-11-01

    Full Text Available Brain is continuously altered in response to experience and environmental changes. One of the underlying mechanisms is synaptic plasticity, which is manifested by modification of synapse structure and function. It is becoming clear that regulated extracellular proteolysis plays a pivotal role in the structural and functional remodeling of synapses during brain development, learning and memory formation. Clearly, plasticity mechanisms may substantially differ between projections. Mossy fiber synapses onto CA3 pyramidal cells display several unique functional features, including pronounced short-term facilitation, a presynaptically expressed LTP that is independent of NMDAR activation, and NMDA-dependent metaplasticity. Moreover, structural plasticity at mossy fiber synapses ranges from the reorganization of projection topology after hippocampus-dependent learning, through intrinsically different dynamic properties of synaptic boutons to pre- and postsynaptic structural changes accompanying LTP induction. Although concomitant functional and structural plasticity in this pathway strongly suggests a role of extracellular proteolysis, its impact only starts to be investigated in this projection. In the present report, we review the role of extracellular proteolysis in various aspects of synaptic plasticity in hippocampal mossy fiber synapses. A growing body of evidence demonstrates that among perisynaptic proteases, tPA/plasmin system, β-site amyloid precursor protein-cleaving enzyme 1 (BACE1 and metalloproteinases play a crucial role in shaping plastic changes in this projection. We discuss recent advances and emerging hypotheses on the roles of proteases in mechanisms underlying mossy fiber target specific synaptic plasticity and memory formation.

  19. Global plastic models for computerized structural analysis

    International Nuclear Information System (INIS)

    Roche, R.; Hoffmann, A.

    1977-01-01

    Two different global models are used in the CEASEMT system for structural analysis, one for the shells analysis and the other for piping analysis (in plastic or creep field). In shell analysis the generalized stresses choosed are the membrane forces Nsub(ij) and bending (including torsion) moments Msub(ij). There is only one yield condition for a normal (to the middle surface) and no integration along the thickness is required. In piping analysis, the choice of generalized stresses is: bending moments, torsional moments, Hoop stress and tension stress. There is only a set of stresses for a cross section and non integration over the cross section area is needed. Connected strains are axis curvature, torsion, uniform strains. The definition of the yield surface is the most important item. A practical way is to use a diagonal quadratic fonction of the stress components. But the coefficients are depending of the shape of the pipe element, especially for curved segments. Indications will be given on the yield fonctions used. Some examples of applications in structural analysis are added to the text [fr

  20. Thermo-plastic finite element analysis for metal honeycomb structure

    Directory of Open Access Journals (Sweden)

    Ji Zhanling

    2013-01-01

    Full Text Available This paper deals with thermal-plastic analysis for the metal honeycomb structure. The heat transfer equation and thermal elastoplastic constitutive equation of a multilayer panel are established and studied numerically using ANSYS software. The paper elucidates that only the outer skin produces easily plastic deformation, and the outer skin still exists some residual stress and residual deformation after cooling. The dynamic evolution of plastic deformation and material performance degradation under high energy thermal load are revealed.

  1. Rigid-plastic seismic design of reinforced concrete structures

    DEFF Research Database (Denmark)

    Costa, Joao Domingues; Bento, R.; Levtchitch, V.

    2007-01-01

    structural strength with respect to a pre-defined performance parameter using a rigid-plastic response spectrum, which is characteristic of the ground motion alone. The maximum strength demand at any point is solely dependent on the intensity of the ground motion, which facilitates the task of distributing......In this paper a new seismic design procedure for Reinforced Concrete (R/C) structures is proposed-the Rigid-Plastic Seismic Design (RPSD) method. This is a design procedure based on Non-Linear Time-History Analysis (NLTHA) for systems expected to perform in the non-linear range during a lifetime...... earthquake event. The theoretical background is the Theory of Plasticity (Rigid-Plastic Structures). Firstly, a collapse mechanism is chosen and the corresponding stress field is made safe outside the regions where plastic behaviour takes place. It is shown that this allows the determination of the required...

  2. Characteristics of Structural Breakdown in Plastic Concrete and ...

    African Journals Online (AJOL)

    Characteristics of Structural Breakdown in Plastic Concrete and Their Potentials for Quality Control. ... A typical trace has four such significant features which characterise the mix. The significance of these features are analysed in relation to the functional requirements of plastic concrete in practice. Finally, the potentials of ...

  3. Video-game play induces plasticity in the visual system of adults with amblyopia.

    Directory of Open Access Journals (Sweden)

    Roger W Li

    2011-08-01

    Full Text Available UNLABELLED: Abnormal visual experience during a sensitive period of development disrupts neuronal circuitry in the visual cortex and results in abnormal spatial vision or amblyopia. Here we examined whether playing video games can induce plasticity in the visual system of adults with amblyopia. Specifically 20 adults with amblyopia (age 15-61 y; visual acuity: 20/25-20/480, with no manifest ocular disease or nystagmus were recruited and allocated into three intervention groups: action videogame group (n = 10, non-action videogame group (n = 3, and crossover control group (n = 7. Our experiments show that playing video games (both action and non-action games for a short period of time (40-80 h, 2 h/d using the amblyopic eye results in a substantial improvement in a wide range of fundamental visual functions, from low-level to high-level, including visual acuity (33%, positional acuity (16%, spatial attention (37%, and stereopsis (54%. Using a cross-over experimental design (first 20 h: occlusion therapy, and the next 40 h: videogame therapy, we can conclude that the improvement cannot be explained simply by eye patching alone. We quantified the limits and the time course of visual plasticity induced by video-game experience. The recovery in visual acuity that we observed is at least 5-fold faster than would be expected from occlusion therapy in childhood amblyopia. We used positional noise and modelling to reveal the neural mechanisms underlying the visual improvements in terms of decreased spatial distortion (7% and increased processing efficiency (33%. Our study had several limitations: small sample size, lack of randomization, and differences in numbers between groups. A large-scale randomized clinical study is needed to confirm the therapeutic value of video-game treatment in clinical situations. Nonetheless, taken as a pilot study, this work suggests that video-game play may provide important principles for treating amblyopia

  4. Video-game play induces plasticity in the visual system of adults with amblyopia.

    Science.gov (United States)

    Li, Roger W; Ngo, Charlie; Nguyen, Jennie; Levi, Dennis M

    2011-08-01

    Abnormal visual experience during a sensitive period of development disrupts neuronal circuitry in the visual cortex and results in abnormal spatial vision or amblyopia. Here we examined whether playing video games can induce plasticity in the visual system of adults with amblyopia. Specifically 20 adults with amblyopia (age 15-61 y; visual acuity: 20/25-20/480, with no manifest ocular disease or nystagmus) were recruited and allocated into three intervention groups: action videogame group (n = 10), non-action videogame group (n = 3), and crossover control group (n = 7). Our experiments show that playing video games (both action and non-action games) for a short period of time (40-80 h, 2 h/d) using the amblyopic eye results in a substantial improvement in a wide range of fundamental visual functions, from low-level to high-level, including visual acuity (33%), positional acuity (16%), spatial attention (37%), and stereopsis (54%). Using a cross-over experimental design (first 20 h: occlusion therapy, and the next 40 h: videogame therapy), we can conclude that the improvement cannot be explained simply by eye patching alone. We quantified the limits and the time course of visual plasticity induced by video-game experience. The recovery in visual acuity that we observed is at least 5-fold faster than would be expected from occlusion therapy in childhood amblyopia. We used positional noise and modelling to reveal the neural mechanisms underlying the visual improvements in terms of decreased spatial distortion (7%) and increased processing efficiency (33%). Our study had several limitations: small sample size, lack of randomization, and differences in numbers between groups. A large-scale randomized clinical study is needed to confirm the therapeutic value of video-game treatment in clinical situations. Nonetheless, taken as a pilot study, this work suggests that video-game play may provide important principles for treating amblyopia, and perhaps other

  5. Video-Game Play Induces Plasticity in the Visual System of Adults with Amblyopia

    Science.gov (United States)

    Li, Roger W.; Ngo, Charlie; Nguyen, Jennie; Levi, Dennis M.

    2011-01-01

    Abnormal visual experience during a sensitive period of development disrupts neuronal circuitry in the visual cortex and results in abnormal spatial vision or amblyopia. Here we examined whether playing video games can induce plasticity in the visual system of adults with amblyopia. Specifically 20 adults with amblyopia (age 15–61 y; visual acuity: 20/25–20/480, with no manifest ocular disease or nystagmus) were recruited and allocated into three intervention groups: action videogame group (n = 10), non-action videogame group (n = 3), and crossover control group (n = 7). Our experiments show that playing video games (both action and non-action games) for a short period of time (40–80 h, 2 h/d) using the amblyopic eye results in a substantial improvement in a wide range of fundamental visual functions, from low-level to high-level, including visual acuity (33%), positional acuity (16%), spatial attention (37%), and stereopsis (54%). Using a cross-over experimental design (first 20 h: occlusion therapy, and the next 40 h: videogame therapy), we can conclude that the improvement cannot be explained simply by eye patching alone. We quantified the limits and the time course of visual plasticity induced by video-game experience. The recovery in visual acuity that we observed is at least 5-fold faster than would be expected from occlusion therapy in childhood amblyopia. We used positional noise and modelling to reveal the neural mechanisms underlying the visual improvements in terms of decreased spatial distortion (7%) and increased processing efficiency (33%). Our study had several limitations: small sample size, lack of randomization, and differences in numbers between groups. A large-scale randomized clinical study is needed to confirm the therapeutic value of video-game treatment in clinical situations. Nonetheless, taken as a pilot study, this work suggests that video-game play may provide important principles for treating amblyopia, and perhaps

  6. Earthquake excited elasto-plastic structures

    DEFF Research Database (Denmark)

    Randrup-thomsen, Søren; Heuer, R.

    1996-01-01

    Studies of the single degree of freedom elasto-plastic oscillator is well-known in the literature. Some of these works use an associated linear system to describe special features in non-linear domains. One very successful work of this kind uses the socalled Slepian model process related to the a...

  7. Formation of disorientations in dislocation structures during plastic deformation

    DEFF Research Database (Denmark)

    Pantleon, W.

    2002-01-01

    Disorientations developing during plastic deformation in dislocation structures are investigated. Based on expected mechanisms for the formation of different types of dislocation boundaries (statistical trapping of dislocations or differently activated slip systems) the formation of the disorient...

  8. Tailoring dislocation structures and mechanical properties of nanostructured metals produced by plastic deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2009-01-01

    The presence of a dislocation structure associated with low-angle dislocation boundaries and interior dislocations is a common and characteristic feature in nanostructured metals produced by plastic deformation, and plays an important role in determining both the strength and ductility...

  9. Influence of preliminary plastic deformation on plasticity characteristics and structure of armco-iron

    International Nuclear Information System (INIS)

    Vergazov, A.N.; Rybin, V.V.; Meshkov, Yu.Ya.; Moskvina, V.A.; Serditova, T.N.

    1990-01-01

    Effect of preliminary plastic deformation (PPD) by drawing on the maximum plasticity characteristics (critical rupture strain) ε c , general δ and uniform δ p relative elongation and on the structure of armco-iron in a wide range of PPD degree change (e=0-4.6) is studied. It is ascertained that with e growth the metal plastic properties at T test =77 and 293 K change in a different way. In particular, the critical strain ε c increases monotonously at 77 K and reduces at 293 K. It is shown that all changes of mechanical characteristics observed with e increase are conditioned by the development of fragmentation process in armco-iron. The data obtained are discussed from the veiwpoint of the developed plastic deformation physics concepts

  10. Cyclic plastic hinges with degradation effects for frame structures

    DEFF Research Database (Denmark)

    Tidemann, Lasse; Krenk, Steen

    2017-01-01

    A model of cyclic plastic hinges in frame structures including degradation effects for stiffness and strength is developed. The model is formulated via potentials in terms of section forces. It consists of a yield surface, described in a generic format permitting representation of general convex...... shapes including corners, and a set of evolution equations based on an internal energy potential and a plastic flow potential. The form of these potentials is specified by five parameters for each generalized stress-strain component describing yield level, ultimate stress capacity, elastic...... and stiffness parameters. The cyclic plastic hinges are introduced into a six-component equilibrium-based beam element, using additive element and hinge flexibilities. When converted to stiffness format the plastic hinges are incorporated into the element stiffness matrix. The cyclic plastic hinge model...

  11. An elastic-plastic contact model for line contact structures

    Science.gov (United States)

    Zhu, Haibin; Zhao, Yingtao; He, Zhifeng; Zhang, Ruinan; Ma, Shaopeng

    2018-06-01

    Although numerical simulation tools are now very powerful, the development of analytical models is very important for the prediction of the mechanical behaviour of line contact structures for deeply understanding contact problems and engineering applications. For the line contact structures widely used in the engineering field, few analytical models are available for predicting the mechanical behaviour when the structures deform plastically, as the classic Hertz's theory would be invalid. Thus, the present study proposed an elastic-plastic model for line contact structures based on the understanding of the yield mechanism. A mathematical expression describing the global relationship between load history and contact width evolution of line contact structures was obtained. The proposed model was verified through an actual line contact test and a corresponding numerical simulation. The results confirmed that this model can be used to accurately predict the elastic-plastic mechanical behaviour of a line contact structure.

  12. Structural and Functional Plasticity in the Maternal Brain Circuitry

    Science.gov (United States)

    Pereira, Mariana

    2016-01-01

    Parenting recruits a distributed network of brain structures (and neuromodulators) that coordinates caregiving responses attuned to the young's affect, needs, and developmental stage. Many of these structures and connections undergo significant structural and functional plasticity, mediated by the interplay between maternal hormones and social…

  13. Marine microbe with potential to adhere and degrade plastic structures

    Directory of Open Access Journals (Sweden)

    Alka Kumari

    2017-10-01

    Full Text Available Extensive usages of plastics have led to their accumulation as a contaminant in natural environment worldwide. Plastic is an inert and non-biodegradable material, due to its complex structure and hydrophobic backbone [1]. Conventional methods for reduction of plastic waste such as burning, land-filling release unwanted toxic chemicals to the environment and harming living organism of land as well as the ocean. There is growing interest in development of strategies for the degradation of plastic wastes to clean the environment [2]. Marine bacteria have evolved with the capability to adapt and grow in the diverse environmental conditions [3]. We studied the ability of marine bacteria for destabilization and utilization of different plastic films (LDPE, HDPE, PVC and PET as a sole source of carbon. An active bacterial strain AIIW2 was selected based on the triphenyl tetrazolium chloride reduction assay, and it was identified as Bacillus species based on 16S rRNA gene sequence. The viability of the strain over the plastic surface was studied and confirmed by bacLight assay with fluorescent probes. Scanning Electron Microscope and Atomic Force Microscope images suggested that bacterial interaction over the plastic surface is causing deterioration and roughness with increasing bacterial incubation time. In Fourier transform infrared spectra of treated plastic film evidenced stretching of the (-CH alkane rock chain and (-CO carbonyl region, suggested the oxidative activities of the bacteria. The results revealed that ability of bacterial strain for instigating their colonization over plastic films and deteriorating the polymeric structure in the absence of other carbon sources [4]. Moreover, production of extracellular enzymes such as esterase, laccase, and dehalogenase which are reported to support utilization of plastics was confirmed by plate assays. In concise, our results suggested that the marine bacterial strain AIIW2 have the ability to utilize

  14. Cyclic plastic hinges with degradation effects for frame structures

    OpenAIRE

    Tidemann, Lasse; Krenk, Steen

    2017-01-01

    A model of cyclic plastic hinges in frame structures including degradation effects for stiffness and strength is developed. The model is formulated via potentials in terms of section forces. It consists of a yield surface, described in a generic format permitting representation of general convex shapes including corners, and a set of evolution equations based on an internal energy potential and a plastic flow potential. The form of these potentials is specified by five parameters for each gen...

  15. Conflicts in Chemistry: The Case of Plastics, a Role-Playing Game for High School Chemistry Students

    Science.gov (United States)

    Cook, Deborah H.

    2014-01-01

    Conflicts in Chemistry: The Case of Plastics, an innovative role-playing activity for high school students, was developed by the Chemical Heritage Foundation to promote increased public understanding of chemistry. The pilot program included three high school teachers and their students at three different schools and documented implementation and…

  16. The Plastic Surgeon at Work and Play: Surgeon Health, Practice Stress, and Work-Home Balance.

    Science.gov (United States)

    Bentz, Michael L

    2016-10-01

    Plastic surgeon wellness encompasses physical and mental health, considered in the context of practice stress. In addition, the challenges of work-home balance can lead to substantial negative impact on the surgeon, family, staff, and patients. The data-driven impact of each of these three components with personal vignettes, both individually and collectively, is presented by Michael Bentz, MD as the 2016 presidential address of American Association of Plastic Surgeons.

  17. Play in two societies: pervasiveness of process, specificity of structure.

    Science.gov (United States)

    Bornstein, M H; Haynes, O M; Pascual, L; Painter, K M; Galperín, C

    1999-01-01

    The present study compared Argentine (N = 39) and U.S. (N = 43) children and their mothers on exploratory, symbolic, and social play and interaction when children were 20 months of age. Patterns of cultural similarity and difference emerged. In both cultures, boys engaged in more exploratory play than girls, and girls engaged in more symbolic play than boys; mothers of boys engaged in more exploratory play than mothers of girls, and mothers of girls engaged in more symbolic play than mothers of boys. Moreover, in both cultures, individual variation in children's exploratory and symbolic play was specifically associated with individual variation in mothers' exploratory and symbolic play, respectively. Between cultures, U.S. children and their mothers engaged in more exploratory play, whereas Argentine children and their mothers engaged in more symbolic play. Moreover, Argentine mothers exceeded U.S. mothers in social play and verbal praise of their children. During an early period of mental and social growth, general developmental processes in play may be pervasive, but dyadic and cultural structures are apparently specific. Overall, Argentine and U.S. dyads utilized different modes of exploration, representation, and interaction--emphasizing "other-directed" acts of pretense versus "functional" and "combinatorial" exploration, for example--and these individual and dyadic allocentric versus idiocentric stresses accord with larger cultural concerns of collectivism versus individualism in the two societies.

  18. Asymptotic techniques in elastic-plastic analysis of structures

    International Nuclear Information System (INIS)

    Sayir, M.

    1983-01-01

    Elastic-plastic structures can nowadays be analyzed with the powerful numerical procedures of the finite element method. Nevertheless, in many engineering applications, analytical expressions capable of predicting with sufficient accuracy the stress distributions, the extent of the plastic zones and the load displacement behaviour could be of great practical value. For simple structures and loading stages not too far from the elastic limit, such analytical expressions may be obtained by using perturbation methods and asymptotic expansions. A small dimensionless parameter epsilon is defined as the ratio of a length characterizing the extent of the narrow plastic zone, to a conveniently chosen typical dimension of the structure. Stresses and displacements are formally expanded as asymptotic series in terms of powers of epsilon. For each order of magnitude, the exact basic relations lead to a separate set of simplified differential equations which can be integrated analytically or numerically by using standard procedures. The method is very general and can be applied to several classes of plastic behaviour and of structural problems. Three examples of very simple structures are chosen in particular to illustrate the applicability of the perturbation method to engineering problems. (orig./RW)

  19. Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Mengal Ali Nawaz

    2014-07-01

    Full Text Available In this study, Basalt fiber reinforced plastic (BFRP wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP. Finite element analysis (FEA of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength compared to GFRP wind turbine blade.

  20. An overview of structural characteristics in problematic video game playing

    OpenAIRE

    Griffiths, MD; Nuyens, F

    2017-01-01

    Purpose of Review: There are many different factors involved in how and why people develop problems with video game playing. One such set of factors concerns the structural characteristics of video games (i.e., the structure, elements, and components of the video games themselves). Much of the research examining the structural characteristics of video games was initially based on research and theorizing from the gambling studies field. The present review briefly overviews the key papers in th...

  1. WW II "guinea pigs" played crucial role in refining plastic surgery in Canada

    OpenAIRE

    Wilton, P

    1998-01-01

    When WW II started, Canada had only 4 plastic surgeons. One of them, Dr. Ross Tilley, would treat hundreds of Allied airmen whose bodies needed massive reconstruction because of war injuries. These men became known as the guinea pigs, and Tilley would bring the lessons he learned on them back to Canada.

  2. Reliability Analysis of Elasto-Plastic Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Sørensen, John Dalsgaard

    1984-01-01

    . Failure of this type of system is defined either as formation of a mechanism or by failure of a prescribed number of elements. In the first case failure is independent of the order in which the elements fail, but this is not so by the second definition. The reliability analysis consists of two parts...... are described and the two definitions of failure can be used by the first formulation, but only the failure definition based on formation of a mechanism by the second formulation. The second part of the reliability analysis is an estimate of the failure probability for the structure on the basis...

  3. Shaping inhibition: activity dependent structural plasticity of GABAergic synapses

    Directory of Open Access Journals (Sweden)

    Carmen E Flores

    2014-10-01

    Full Text Available Inhibitory transmission through the neurotransmitter Ɣ-aminobutyric acid (GABA shapes network activity in the mammalian cerebral cortex by filtering synaptic incoming information and dictating the activity of principal cells. The incredibly diverse population of cortical neurons that use GABA as neurotransmitter shows an equally diverse range of mechanisms that regulate changes in the strength of GABAergic synaptic transmission and allow them to dynamically follow and command the activity of neuronal ensembles. Similarly to glutamatergic synaptic transmission, activity-dependent functional changes in inhibitory neurotransmission are accompanied by alterations in GABAergic synapse structure that range from morphological reorganization of postsynaptic density to de novo formation and elimination of inhibitory contacts. Here we review several aspects of structural plasticity of inhibitory synapses, including its induction by different forms of neuronal activity, behavioral and sensory experience and the molecular mechanisms and signaling pathways involved. We discuss the functional consequences of GABAergic synapse structural plasticity for information processing and memory formation in view of the heterogenous nature of the structural plasticity phenomena affecting inhibitory synapses impinging on somatic and dendritic compartments of cortical and hippocampal neurons.

  4. An Overview of Structural Characteristics in Problematic Video Game Playing.

    Science.gov (United States)

    Griffiths, Mark D; Nuyens, Filip

    2017-01-01

    There are many different factors involved in how and why people develop problems with video game playing. One such set of factors concerns the structural characteristics of video games (i.e., the structure, elements, and components of the video games themselves). Much of the research examining the structural characteristics of video games was initially based on research and theorizing from the gambling studies field. The present review briefly overviews the key papers in the field to date. The paper examines a number of areas including (i) similarities in structural characteristics of gambling and video gaming, (ii) structural characteristics in video games, (iii) narrative and flow in video games, (iv) structural characteristic taxonomies for video games, and (v) video game structural characteristics and game design ethics. Many of the studies carried out to date are small-scale, and comprise self-selected convenience samples (typically using self-report surveys or non-ecologically valid laboratory experiments). Based on the small amount of empirical data, it appears that structural features that take a long time to achieve in-game are the ones most associated with problematic video game play (e.g., earning experience points, managing in-game resources, mastering the video game, getting 100% in-game). The study of video games from a structural characteristic perspective is of benefit to many different stakeholders including academic researchers, video game players, and video game designers, as well as those interested in prevention and policymaking by making the games more socially responsible. It is important that researchers understand and recognize the psycho-social effects and impacts that the structural characteristics of video games can have on players, both positive and negative.

  5. Playing and Listening to Tailor-Made Notched Music: Cortical Plasticity Induced by Unimodal and Multimodal Training in Tinnitus Patients

    Directory of Open Access Journals (Sweden)

    Janna Pape

    2014-01-01

    Full Text Available Background. The generation and maintenance of tinnitus are assumed to be based on maladaptive functional cortical reorganization. Listening to modified music, which contains no energy in the range of the individual tinnitus frequency, can inhibit the corresponding neuronal activity in the auditory cortex. Music making has been shown to be a powerful stimulator for brain plasticity, inducing changes in multiple sensory systems. Using magnetoencephalographic (MEG and behavioral measurements we evaluated the cortical plasticity effects of two months of (a active listening to (unisensory versus (b learning to play (multisensory tailor-made notched music in nonmusician tinnitus patients. Taking into account the fact that uni- and multisensory trainings induce different patterns of cortical plasticity we hypothesized that these two protocols will have different affects. Results. Only the active listening (unisensory group showed significant reduction of tinnitus related activity of the middle temporal cortex and an increase in the activity of a tinnitus-coping related posterior parietal area. Conclusions. These findings indicate that active listening to tailor-made notched music induces greater neuroplastic changes in the maladaptively reorganized cortical network of tinnitus patients while additional integration of other sensory modalities during training reduces these neuroplastic effects.

  6. Playing and listening to tailor-made notched music: cortical plasticity induced by unimodal and multimodal training in tinnitus patients.

    Science.gov (United States)

    Pape, Janna; Paraskevopoulos, Evangelos; Bruchmann, Maximilian; Wollbrink, Andreas; Rudack, Claudia; Pantev, Christo

    2014-01-01

    BACKGROUND. The generation and maintenance of tinnitus are assumed to be based on maladaptive functional cortical reorganization. Listening to modified music, which contains no energy in the range of the individual tinnitus frequency, can inhibit the corresponding neuronal activity in the auditory cortex. Music making has been shown to be a powerful stimulator for brain plasticity, inducing changes in multiple sensory systems. Using magnetoencephalographic (MEG) and behavioral measurements we evaluated the cortical plasticity effects of two months of (a) active listening to (unisensory) versus (b) learning to play (multisensory) tailor-made notched music in nonmusician tinnitus patients. Taking into account the fact that uni- and multisensory trainings induce different patterns of cortical plasticity we hypothesized that these two protocols will have different affects. RESULTS. Only the active listening (unisensory) group showed significant reduction of tinnitus related activity of the middle temporal cortex and an increase in the activity of a tinnitus-coping related posterior parietal area. CONCLUSIONS. These findings indicate that active listening to tailor-made notched music induces greater neuroplastic changes in the maladaptively reorganized cortical network of tinnitus patients while additional integration of other sensory modalities during training reduces these neuroplastic effects.

  7. Structural brain correlates associated with professional handball playing.

    Science.gov (United States)

    Hänggi, Jürgen; Langer, Nicolas; Lutz, Kai; Birrer, Karin; Mérillat, Susan; Jäncke, Lutz

    2015-01-01

    There is no doubt that good bimanual performance is very important for skilled handball playing. The control of the non-dominant hand is especially demanding since efficient catching and throwing needs both hands. We investigated training-induced structural neuroplasticity in professional handball players using several structural neuroimaging techniques and analytic approaches and also provide a review of the literature about sport-induced structural neuroplastic alterations. Structural brain adaptations were expected in regions relevant for motor and somatosensory processing such as the grey matter (GM) of the primary/secondary motor (MI/supplementary motor area, SMA) and somatosensory cortex (SI/SII), basal ganglia, thalamus, and cerebellum and in the white matter (WM) of the corticospinal tract (CST) and corpus callosum, stronger in brain regions controlling the non-dominant left hand. Increased GM volume in handball players compared with control subjects were found in the right MI/SI, bilateral SMA/cingulate motor area, and left intraparietal sulcus. Fractional anisotropy (FA) and axial diffusivity were increased within the right CST in handball players compared with control women. Age of handball training commencement correlated inversely with GM volume in the right and left MI/SI and years of handball training experience correlated inversely with radial diffusivity in the right CST. Subcortical structures tended to be larger in handball players. The anatomical measures of the brain regions associated with handball playing were positively correlated in handball players, but not interrelated in control women. Training-induced structural alterations were found in the somatosensory-motor network of handball players, more pronounced in the right hemisphere controlling the non-dominant left hand. Correlations between handball training-related measures and anatomical differences suggest neuroplastic adaptations rather than a genetic predisposition for a ball playing

  8. Structural brain correlates associated with professional handball playing.

    Directory of Open Access Journals (Sweden)

    Jürgen Hänggi

    Full Text Available There is no doubt that good bimanual performance is very important for skilled handball playing. The control of the non-dominant hand is especially demanding since efficient catching and throwing needs both hands.We investigated training-induced structural neuroplasticity in professional handball players using several structural neuroimaging techniques and analytic approaches and also provide a review of the literature about sport-induced structural neuroplastic alterations. Structural brain adaptations were expected in regions relevant for motor and somatosensory processing such as the grey matter (GM of the primary/secondary motor (MI/supplementary motor area, SMA and somatosensory cortex (SI/SII, basal ganglia, thalamus, and cerebellum and in the white matter (WM of the corticospinal tract (CST and corpus callosum, stronger in brain regions controlling the non-dominant left hand.Increased GM volume in handball players compared with control subjects were found in the right MI/SI, bilateral SMA/cingulate motor area, and left intraparietal sulcus. Fractional anisotropy (FA and axial diffusivity were increased within the right CST in handball players compared with control women. Age of handball training commencement correlated inversely with GM volume in the right and left MI/SI and years of handball training experience correlated inversely with radial diffusivity in the right CST. Subcortical structures tended to be larger in handball players. The anatomical measures of the brain regions associated with handball playing were positively correlated in handball players, but not interrelated in control women.Training-induced structural alterations were found in the somatosensory-motor network of handball players, more pronounced in the right hemisphere controlling the non-dominant left hand. Correlations between handball training-related measures and anatomical differences suggest neuroplastic adaptations rather than a genetic predisposition for a

  9. Structural Brain Correlates Associated with Professional Handball Playing

    Science.gov (United States)

    Hänggi, Jürgen; Langer, Nicolas; Lutz, Kai; Birrer, Karin; Mérillat, Susan; Jäncke, Lutz

    2015-01-01

    Background There is no doubt that good bimanual performance is very important for skilled handball playing. The control of the non-dominant hand is especially demanding since efficient catching and throwing needs both hands. Methodology/Hypotheses We investigated training-induced structural neuroplasticity in professional handball players using several structural neuroimaging techniques and analytic approaches and also provide a review of the literature about sport-induced structural neuroplastic alterations. Structural brain adaptations were expected in regions relevant for motor and somatosensory processing such as the grey matter (GM) of the primary/secondary motor (MI/supplementary motor area, SMA) and somatosensory cortex (SI/SII), basal ganglia, thalamus, and cerebellum and in the white matter (WM) of the corticospinal tract (CST) and corpus callosum, stronger in brain regions controlling the non-dominant left hand. Results Increased GM volume in handball players compared with control subjects were found in the right MI/SI, bilateral SMA/cingulate motor area, and left intraparietal sulcus. Fractional anisotropy (FA) and axial diffusivity were increased within the right CST in handball players compared with control women. Age of handball training commencement correlated inversely with GM volume in the right and left MI/SI and years of handball training experience correlated inversely with radial diffusivity in the right CST. Subcortical structures tended to be larger in handball players. The anatomical measures of the brain regions associated with handball playing were positively correlated in handball players, but not interrelated in control women. Discussion/Conclusion Training-induced structural alterations were found in the somatosensory-motor network of handball players, more pronounced in the right hemisphere controlling the non-dominant left hand. Correlations between handball training-related measures and anatomical differences suggest neuroplastic

  10. Structural Components of Synaptic Plasticity and Memory Consolidation

    Science.gov (United States)

    Bailey, Craig H.; Kandel, Eric R.; Harris, Kristen M.

    2015-01-01

    Consolidation of implicit memory in the invertebrate Aplysia and explicit memory in the mammalian hippocampus are associated with remodeling and growth of preexisting synapses and the formation of new synapses. Here, we compare and contrast structural components of the synaptic plasticity that underlies these two distinct forms of memory. In both cases, the structural changes involve time-dependent processes. Thus, some modifications are transient and may contribute to early formative stages of long-term memory, whereas others are more stable, longer lasting, and likely to confer persistence to memory storage. In addition, we explore the possibility that trans-synaptic signaling mechanisms governing de novo synapse formation during development can be reused in the adult for the purposes of structural synaptic plasticity and memory storage. Finally, we discuss how these mechanisms set in motion structural rearrangements that prepare a synapse to strengthen the same memory and, perhaps, to allow it to take part in other memories as a basis for understanding how their anatomical representation results in the enhanced expression and storage of memories in the brain. PMID:26134321

  11. The study of elastio-plastic seismic analysis for rigid-frame structures

    OpenAIRE

    陳, 珉; 青木, 徹彦

    2000-01-01

    Elastic and elastio-plastic earthquake-resistant analysis of frame construction is mainly studied in this paper. In elastic stage, response and vibrated characteristics of symmetrical and unsymmetrical structure are investigated by comparing the results of plane and space analysis. The effect of approaching angle of seismic wave to vibrated characteristics of structure under different column/beam rate are discussed. In elastio-plastic stage, four kinds of plastic mode with different plastic p...

  12. Structural plasticity: how intermetallics deform themselves in response to chemical pressure, and the complex structures that result.

    Science.gov (United States)

    Berns, Veronica M; Fredrickson, Daniel C

    2014-10-06

    Interfaces between periodic domains play a crucial role in the properties of metallic materials, as is vividly illustrated by the way in which the familiar malleability of many metals arises from the formation and migration of dislocations. In complex intermetallics, such interfaces can occur as an integral part of the ground-state crystal structure, rather than as defects, resulting in such marvels as the NaCd2 structure (whose giant cubic unit cell contains more than 1000 atoms). However, the sources of the periodic interfaces in intermetallics remain mysterious, unlike the dislocations in simple metals, which can be associated with the exertion of physical stresses. In this Article, we propose and explore the concept of structural plasticity, the hypothesis that interfaces in complex intermetallic structures similarly result from stresses, but ones that are inherent in a defect-free parent structure, rather than being externally applied. Using DFT-chemical pressure analysis, we show how the complex structures of Ca2Ag7 (Yb2Ag7 type), Ca14Cd51 (Gd14Ag51 type), and the 1/1 Tsai-type quasicrystal approximant CaCd6 (YCd6 type) can all be traced to large negative pressures around the Ca atoms of a common progenitor structure, the CaCu5 type with its simple hexagonal 6-atom unit cell. Two structural paths are found by which the compounds provide relief to the Ca atoms' negative pressures: a Ca-rich pathway, where lower coordination numbers are achieved through defects eliminating transition metal (TM) atoms from the structure; and a TM-rich path, along which the addition of spacer Cd atoms provides the Ca coordination environments greater independence from each other as they contract. The common origins of these structures in the presence of stresses within a single parent structure highlights the diverse paths by which intermetallics can cope with competing interactions, and the role that structural plasticity may play in navigating this diversity.

  13. Fundamental structure of steady plastic shock waves in metals

    International Nuclear Information System (INIS)

    Molinari, A.; Ravichandran, G.

    2004-01-01

    The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic-plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large deformations. The material response is characterized by a quasistatic tensile (compression) test (providing the isothermal strain hardening law). In addition the elastic response is determined up to second order elastic constants by ultrasonic measurements. Based on this simple information, it is shown that the shock kinetics can be quite well described for moderate shocks in aluminum with stress amplitude up to 10 GPa. Under the later assumption, the elastic response is assumed to be isentropic, and thermomechanical coupling is neglected. The model material considered here is aluminum, but the analysis is general and can be applied to any viscoplastic material subjected to moderate amplitude shocks. Comparisons with experimental data are made for the shock velocity, the particle velocity and the shock structure. The shock structure is obtained by quadrature of a first order differential equation, which provides analytical results under certain simplifying assumptions. The effects of material parameters and loading conditions on the shock kinetics and shock structure are discussed. The shock width is characterized by assuming an overstress formulation for the viscoplastic response. The effects on the shock structure of strain rate sensitivity are analyzed and the rationale for the J. W. Swegle and D. E. Grady [J. Appl. Phys. 58, 692 (1985)] universal scaling law for homogeneous materials is explored. Finally, the ability to deduce information on the viscoplastic response of

  14. Fundamental structure of steady plastic shock waves in metals

    Science.gov (United States)

    Molinari, A.; Ravichandran, G.

    2004-02-01

    The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic-plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large deformations. The material response is characterized by a quasistatic tensile (compression) test (providing the isothermal strain hardening law). In addition the elastic response is determined up to second order elastic constants by ultrasonic measurements. Based on this simple information, it is shown that the shock kinetics can be quite well described for moderate shocks in aluminum with stress amplitude up to 10 GPa. Under the later assumption, the elastic response is assumed to be isentropic, and thermomechanical coupling is neglected. The model material considered here is aluminum, but the analysis is general and can be applied to any viscoplastic material subjected to moderate amplitude shocks. Comparisons with experimental data are made for the shock velocity, the particle velocity and the shock structure. The shock structure is obtained by quadrature of a first order differential equation, which provides analytical results under certain simplifying assumptions. The effects of material parameters and loading conditions on the shock kinetics and shock structure are discussed. The shock width is characterized by assuming an overstress formulation for the viscoplastic response. The effects on the shock structure of strain rate sensitivity are analyzed and the rationale for the J. W. Swegle and D. E. Grady [J. Appl. Phys. 58, 692 (1985)] universal scaling law for homogeneous materials is explored. Finally, the ability to deduce information on the viscoplastic response of

  15. A strategy to compute plastic post-buckling of structures

    International Nuclear Information System (INIS)

    Combescure, A.

    1983-08-01

    The paper gives a general framework to the different strategies used to compute the post-buckling of structures. Two particular strategies are studied in more details and it is shown how they can be applied in the plastic regime. All the methods suppose that the loads F are proportional to a simple parameter lambda; more precisely: eq (1) F = lambda F 0 . The paper shows how these methods can be implemented in a very simple way. In the elastic case we show the application of the method to the calculation of post buckling response of a clamped arch. The method is also applied to a very simple case of two bars which can be calculated analytically. In the plastic range, the method is applied to the post-buckling of an imperfect ring which can be calculated analytically. Another example is the comparison of the comparison of the computed post-buckling of a thin cylinder under axial compression, and of the experimental behavior on the same cylinder. The limitation of these types of strategies are also mentionned and the physical signifiance of calculations in the post-buckling regime are discussed

  16. The differences in physical activity levels in preschool children during free play recess and structured play recess

    Directory of Open Access Journals (Sweden)

    Megan L. Frank

    2018-04-01

    Full Text Available Background/Objective: Physical activity (PA is important in reducing childhood obesity, yet a majority of children are not meeting PA guidelines. Schools have been identified as a place to promote childhood PA. The purpose of this study was to determine the best type of physically active recess period to increase preschool-aged children's PA. Methods: PA was measured via accelerometers in preschool-aged children (n = 29 during three, 30-min recess conditions (control; structured play; free play on separate school days. Tertile splits were performed based on PA during the free play condition and children were divided into three groups: highly, moderately and least active. Results: For the aggregated sample, children were more (p ≤ 0.001 active during the free play (1282 ± 662 counts. min−1 and structured play (1416 ± 448 counts. min−1 recess versus the control condition (570 ± 460 counts. min−1 and activity was not different between the free play and structured conditions. However, children who were the most active during free play (1970 ± 647 counts·min−1 decreased (p ≤ 0.05 activity during structured play (1462 ± 535 counts·min−1, whereas children who were moderately active (1031 ± 112 counts·min−1 or the least (530 ± 239 counts·min−1 active during free play increased activity during structured play (1383 ± 345 counts·min−1 moderately active, 1313 ± 413 counts·min−1 least active. Conclusion: Providing a physically-active recess period will contribute to preschool-aged children meeting the recommended PA guidelines; however, different children may respond in a different way based upon the structure of the recess period.

  17. Closed-form critical earthquake response of elastic-plastic structures on compliant ground under near-fault ground motions

    Directory of Open Access Journals (Sweden)

    Kotaro eKojima

    2016-01-01

    Full Text Available The double impulse is introduced as a substitute of the fling-step near-fault ground motion. A closed-form solution of the elastic-plastic response of a structure on compliant (flexible ground by the ‘critical double impulse’ is derived for the first time based on the solution for the corresponding structure with fixed base. As in the case of fixed-base model, only the free-vibration appears under such double impulse and the energy approach plays an important role in the derivation of the closed-form solution of a complicated elastic-plastic response on compliant ground. It is remarkable that no iteration is needed in the derivation of the critical elastic-plastic response. It is shown via the closed-form expression that, in the case of a smaller input level of double impulse to the structural strength, as the ground stiffness becomes larger, the maximum plastic deformation becomes larger. On the other hand, in the case of a larger input level of double impulse to the structural strength, as the ground stiffness becomes smaller, the maximum plastic deformation becomes larger. The criticality and validity of the proposed theory are investigated through the comparison with the response analysis to the corresponding one-cycle sinusoidal input as a representative of the fling-step near-fault ground motion. The applicability of the proposed theory to actual recorded pulse-type ground motions is also discussed.

  18. Many Activities, One Structure: Functional Plasticity of Ribozyme Folds

    Directory of Open Access Journals (Sweden)

    Matthew W.L. Lau

    2016-11-01

    Full Text Available Catalytic RNAs, or ribozymes, are involved in a number of essential biological processes, such as replication of RNA genomes and mobile genetic elements, RNA splicing, translation, and RNA degradation. The function of ribozymes requires the formation of active sites decorated with RNA functional groups within defined three-dimensional (3D structures. The genotype (sequence of RNAs ultimately determines what 3D structures they adopt (as a function of their environmental conditions. These 3D structures, in turn, give rise to biochemical activity, which can further elaborate them by catalytic rearrangements or association with other molecules. The fitness landscape of a non-periodic linear polymer, such as RNA, relates its primary structure to a phenotype. Two major challenges in the analysis of ribozymes is to map all possible genotypes to their corresponding catalytic activity (that is, to determine their fitness landscape experimentally, and to understand whether their genotypes and three-dimensional structures can support multiple different catalytic functions. Recently, the combined results of experiments that employ in vitro evolution methods, high-throughput sequencing and crystallographic structure determination have hinted at answers to these two questions: while the fitness landscape of ribozymes is rugged, meaning that their catalytic activity cannot be optimized by a smooth trajectory in sequence space, once an RNA achieves a stable three-dimensional fold, it can be endowed with distinctly different biochemical activities through small changes in genotype. This functional plasticity of highly structured RNAs may be particularly advantageous for the adaptation of organisms to drastic changes in selective pressure, or for the development of new biotechnological tools.

  19. Micro-structural evolution in plastically deformed crystalline materials

    DEFF Research Database (Denmark)

    Nellemann, Christopher

    predictions for the two models to be obtained. Application of the two models to the pure shear boundary value problem is used to characterize plastic behavior, which also allows for the identification of inherent properties through closed form expressions. Single crystal Monazite containing a void is studied......Two rate-independent strain gradient crystal plasticity models are developed and applied in numerical studies designed to identify the properties inherent to model predictions of plastic deformation. The two models incorporate gradients of slip into the framework of conventional crystal plasticity...... in order to model size-dependent plasticity effects. This gradient dependence is achieved by relating a slip measure which combines both slip and their gradients to a shear hardening curve, as commonly done in conventional plasticity theories. Finite element codes are implemented which allow for numerical...

  20. Formation of cellular structure in beryllium at plastic working

    International Nuclear Information System (INIS)

    Papirov, I.I.; Nikolaenko, A.A.; Shokurov, V.S.; Pikalov, A.I.

    2013-01-01

    Conditions of cellular structure formation are investigated at various kinds of deformation and heat treatment of beryllium ingots. It is shown that the cellular structure plays the important role in formation of complex of physical mechanical properties of beryllium. Influence of impurity, various conditions of deformation (temperature, squeezing degree) and heat treatments on substructure, texture and mechanical properties of metal is investigated. Optimum conditions of rolling and heat treatments of beryllium are defined. The way of sign-variable cyclic deformation of beryllium ingots is offered for reception quasi-isotropic fine-grained metal. Physical-mechanical properties of ultra fine-grained metal are studied

  1. NMDA Receptors Regulate the Structural Plasticity of Spines and Axonal Boutons in Hippocampal Interneurons

    Directory of Open Access Journals (Sweden)

    Marta Perez-Rando

    2017-06-01

    Full Text Available N-methyl-D-aspartate receptors (NMDARs are present in both pyramidal neurons and interneurons of the hippocampus. These receptors play an important role in the adult structural plasticity of excitatory neurons, but their impact on the remodeling of interneurons is unknown. Among hippocampal interneurons, somatostatin-expressing cells located in the stratum oriens are of special interest because of their functional importance and structural characteristics: they display dendritic spines, which change density in response to different stimuli. In order to understand the role of NMDARs on the structural plasticity of these interneurons, we have injected acutely MK-801, an NMDAR antagonist, to adult mice which constitutively express enhanced green fluorescent protein (EGFP in these cells. We have behaviorally tested the animals, confirming effects of the drug on locomotion and anxiety-related behaviors. NMDARs were expressed in the somata and dendritic spines of somatostatin-expressing interneurons. Twenty-four hours after the injection, the density of spines did not vary, but we found a significant increase in the density of their en passant boutons (EPB. We have also used entorhino-hippocampal organotypic cultures to study these interneurons in real-time. There was a rapid decrease in the apparition rate of spines after MK-801 administration, which persisted for 24 h and returned to basal levels afterwards. A similar reversible decrease was detected in spine density. Our results show that both spines and axons of interneurons can undergo remodeling and highlight NMDARs as regulators of this plasticity. These results are specially relevant given the importance of all these players on hippocampal physiology and the etiopathology of certain psychiatric disorders.

  2. Slepian Simulations of Plastic Displacements of Randomly Excited Hysteretic Structures

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov

    2003-01-01

    The object of the study is a fast simulation method for generation and analysis of the plastic response of a randomly excited MDOF oscillatro with several potential elements with elasto-plastic constitutive behavior. The oscillator is statically determinate with linear damping. The external...... approximately as a stationary Gaussian process. This requires that the standard deviation of the stationary response is not too large as compared to the plastic yield limits. The Slepian model process for the behavior of the linear response is then simply the conditional mean (linear regression) of the process...... noise excited linear oscillator obtained from the elasto-plastic oscillator by totally removing the plastic domain. Thus the key to the applicability of the method is that the oscillator has a linear domain within which the response stays for a sufficiently long time to make the random response behave...

  3. Disruptive Effects of Colorful versus Non-Colorful Play Area on Structured Play – a Pilot Study with Preschoolers

    Directory of Open Access Journals (Sweden)

    Keren Stern-Ellran

    2016-10-01

    Full Text Available To contribute to young children's development, sensory enrichment is often provided via colorful play areas. However, little is known about the effects of colorful environments on children while they engage in age-appropriate tasks and games. Studies in adults suggest that aspects of color can distract attention and impair performance, and children are known to have less developed attentional and executive abilities than adults. Preliminary studies conducted in children aged 5-8 suggest that the colorfulness of both distal (e.g., wall decorations and proximal (e.g., the surface of the desktop environments can have a disruptive effect on children's performance. The present research seeks to extend the previous studies to an even younger age group and focus on proximal colorfulness. With a sample of 15 pre-schoolers (3-4 years old we examined whether a colorful play surface compared to a non-colorful (white play surface would affect engagement in developmentally appropriate structured play. Our pilot findings suggest that a colorful play surface interfered with preschoolers' structured play, inducing more behaviors indicating disruption in task execution compared with a non-colorful play surface. The implications of the current study for practice and further research are discussed.

  4. A strategy to compute plastic post-buckling of structures

    International Nuclear Information System (INIS)

    Combescure, A.

    1983-01-01

    All the methods presented here give in some cases, some interesting computed solutions. It has been remarked that the different strategies do not always give the same post buckling path. More foundamentally, it has been observed that the post buckling path, when buckling is unstable, is characterized by a dynamic movement. All inertial effects are neglected in all the approaches presented here. So that the post buckling load deflections curve is valid only if there is a very little kinetic energy associated with the post buckling. The method is also, as it is presented, limited to a load depending of a simple parameter lambda. The case of more than one parameter is not very clear yet. In conclusion, the method presented here gives a way to solve class of the post buckling behavior of a structure. If the post buckling occurs with a small kinetic energy (displacement controlled buckling) and if the loads depend of only one parameter. These methods should give good results even into the plastic range. If the buckling is unstable and that a large kinetic energy is involved with the post buckling these methods are not realistic. (orig./RW)

  5. Operational factors influence on service life characteristics of structural carbon fiber-reinforced plastic

    OpenAIRE

    Борозенець, Григорій; Павлов, Віктор; Семак, Інна

    2013-01-01

    The nature of strength changing of aircraft structural carbon fiber-reinforced plastic under influence of water saturation after static preloading and mode changing of structural elements forming process pressure is considered.

  6. Fundamental structure of steady plastic shock waves in metals

    OpenAIRE

    Molinari, A.; Ravichandran, G.

    2004-01-01

    The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic–plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large de...

  7. Going for the play: Structural interpretation in offshore Congo

    Energy Technology Data Exchange (ETDEWEB)

    Platt, N.; Philip, P. (GECO-PRAKLA Exploration Services, Woking (United Kingdom)); Walter, S. (ARK Geophysics Ltd., Milton Keynes, (United Kingdom))

    1993-01-01

    Looking for new hydrocarbons in frontier areas, geologists and geophysicists use very trick in the book: plate tectonics, magnetic and gravity data, plain old geological horse sense and lots of seismic data. An interpretation team is followed, as they pick their way through a seismic survey shot in offshore Congo, Africa, searching for those areas (the plays) that show the greatest promise. 17 figs., 9 refs.

  8. Prediction of elastic-plastic response of structural elements subjected to cyclic loading

    International Nuclear Information System (INIS)

    El Haddad, M.H.; Samaan, S.

    1985-01-01

    A simplified elastic-plastic analysis is developed to predict stress strain and force deformation response of structural metallic elements subjected to irregular cyclic loadings. In this analysis a simple elastic-plastic method for predicting the skeleton force deformation curve is developed. In this method, elastic and fully plastic solutions are first obtained for unknown quantities, such as deflection or local strains. Elastic and fully plastic contributions are then combined to obtain an elastic-plastic solution. The skeleton curve is doubled to establish the shape of the hysteresis loop. The complete force deformation response can therefore be simulated through reversal by reversal in accordance with hysteresis looping and material memory. Several examples of structural elements with various cross sections made from various materials and subjected to irregular cyclic loadings, are analysed. A close agreement is obtained between experimental results found in the literature and present predictions. (orig.)

  9. The Role of Structural Characteristics in Problematic Video Game Play: An Empirical Study

    Science.gov (United States)

    King, Daniel L.; Delfabbro, Paul H.; Griffiths, Mark D.

    2011-01-01

    The research literature suggests that the structural characteristics of video games may play a considerable role in the initiation, development and maintenance of problematic video game playing. The present study investigated the role of structural characteristics in video game playing behaviour within a sample of 421 video game players aged…

  10. Application of fibre reinforced plastic sandwich structures for automotive crashworthiness applications

    NARCIS (Netherlands)

    Lukaszewicz, D.; Blok, L.G.; Kratz, J.; Ward, C.; Kassapoglou, C.; Elmarakbi, A.; Araújo, A.L.

    2016-01-01

    In this work the application of fibre reinforced plastic (FRP) sandwich
    structures, with particular focus on aramid fibre tufted sandwiches is being studied for
    automotive crashworthiness applications using impact testing and numerical simulation.

  11. Structural plasticity in Mycobacterium tuberculosis uracil-DNA glycosylase (MtUng) and its functional implications.

    Science.gov (United States)

    Arif, S M; Geethanandan, K; Mishra, P; Surolia, A; Varshney, U; Vijayan, M

    2015-07-01

    17 independent crystal structures of family I uracil-DNA glycosylase from Mycobacterium tuberculosis (MtUng) and its complexes with uracil and its derivatives, distributed among five distinct crystal forms, have been determined. Thermodynamic parameters of binding in the complexes have been measured using isothermal titration calorimetry. The two-domain protein exhibits open and closed conformations, suggesting that the closure of the domain on DNA binding involves conformational selection. Segmental mobility in the enzyme molecule is confined to a 32-residue stretch which plays a major role in DNA binding. Uracil and its derivatives can bind to the protein in two possible orientations. Only one of them is possible when there is a bulky substituent at the 5' position. The crystal structures of the complexes provide a reasonable rationale for the observed thermodynamic parameters. In addition to providing fresh insights into the structure, plasticity and interactions of the protein molecule, the results of the present investigation provide a platform for structure-based inhibitor design.

  12. The application of endochronic plasticity theory in modeling the dynamic inelastic response of structural systems

    International Nuclear Information System (INIS)

    Lin, H.C.; Hsieh, B.J.; Valentin, R.A.

    1981-01-01

    The endochronic theory of plasticity proposed by Valanis has been applied in predicting the inelastic responses of structural systems. A recently developed convected coordinates finite-element program has been modified to use an endochronic constitutive law. A series of sample problems for a variety of dynamic loadings are presented. The calculations that have been performed comparing classical and endochronic plasticity theories have revealed that the endochronic approach can result in a substantial reduction in computer time for equivalent solution accuracy. This result, combined with the apparent accuracy of material representation indicate that the use of endochronic plasticity has great potential in evaluating the dynamic response of structural systems. (orig.)

  13. Thermo-visco-plasticity and creep in structural-material response of folded-plate structures

    Directory of Open Access Journals (Sweden)

    Milašinović Dragan D.

    2017-01-01

    Full Text Available Many structural parts are exposed to high temperatures and loading. It is then important to have data about material inelastic behaviour under such exploiting conditions. Influence of temperature on mechanical characteristics of a material may be inserted via the creep coefficient in the range of visco-elasto-plastic (VEP strains. This damage parameter is implemented in this paper in conjunction with mathematical material modelling approach named rheological-dynamical analogy (RDA in order to address structural stiffness reduction due to inelastic material behaviour. The aim of this paper is to define structural-material internal damping based on both the RDA dynamic modulus and modal damping ratio, by modelling critically damped dynamic systems in the steady-state response. These systems are credible base for explanation of the phenomenon of thermo-visco-plasticity and creep in structural-material response due to high temperatures and loading. Though elastic buckling information for folded-plate structures is not a direct predictor of capacity or collapse behaviour on its own, both the mode and the load (moment are important proxies for the actual behaviour. In current design codes, such as AISI S100, New Zealand/Australia, and European Union, the design formulae are calibrated through the calculation of elastic critical buckling loads (or moments to predict the ultimate strength, thus the ability to calculate the associated elastic buckling loads (or moments has great importance. Moreover, the buckling mode shapes are commonly employed into non-linear collapse modelling as initial geometric imperfections and thermal performance of folded-plate structures in fire. To examine the buckling behaviour of folded-plate structures, the main numerical solution methods are used such as the finite element method (FEM and finite strip method (FSM. This paper aims at providing a unified frame for quasi-static inelastic buckling and thermal loading of

  14. On the bending of structural materials with plastic anisotropic effect

    Science.gov (United States)

    Lachugin, D. V.; Pavilaynen, G. V.

    2018-05-01

    The study of a deformation features of metal alloys which are sensitive to tension or compression loading is an important technical challenge in the design and creation of a new shipbuilding and aircraft constructions. We use a mathematical model for the elastic-plastic bending of such material where SD(strength-different) parameter is taken into account. The problem is solved analytically and numerically. As an example of the material with the SD-effect the steel alloy is considered.

  15. INJECTION MOLDING AND STRUCTURAL ANALYSIS IN METAL TO PLASTIC CONVERSION OF BOLTED FLANGE JOINT BY CAE

    Directory of Open Access Journals (Sweden)

    Marian Blaško

    2014-12-01

    Full Text Available Many metal parts in various applications are being replaced by plastic parts. There are several reasons for that depending on actual application - minimize part cost, enhance corrosion resistance, integrating more components into one part etc. Most important steps of metal to plastic conversion are material selection and design of plastic part. Plastic part has to withstand the same load as metal part. To fulfill this requirement fiber reinforced engineering plastics are often used. Also it is convenient to substitute heavy wall sections with ribbed structure to increase load-carrying ability of part and decrease cycle time, eliminate voids, sink marks etc. Mechanical properties of such part could be highly affected by fiber orientation. Results of fiber orientation from injection molding filling analysis can be used in stress analysis for better prediction of part response to mechanical load. Such coupled analysis is performed here in this case study on bolted flange joint.

  16. Evidence for training-induced plasticity in multisensory brain structures: an MEG study.

    Directory of Open Access Journals (Sweden)

    Evangelos Paraskevopoulos

    Full Text Available Multisensory learning and resulting neural brain plasticity have recently become a topic of renewed interest in human cognitive neuroscience. Music notation reading is an ideal stimulus to study multisensory learning, as it allows studying the integration of visual, auditory and sensorimotor information processing. The present study aimed at answering whether multisensory learning alters uni-sensory structures, interconnections of uni-sensory structures or specific multisensory areas. In a short-term piano training procedure musically naive subjects were trained to play tone sequences from visually presented patterns in a music notation-like system [Auditory-Visual-Somatosensory group (AVS], while another group received audio-visual training only that involved viewing the patterns and attentively listening to the recordings of the AVS training sessions [Auditory-Visual group (AV]. Training-related changes in cortical networks were assessed by pre- and post-training magnetoencephalographic (MEG recordings of an auditory, a visual and an integrated audio-visual mismatch negativity (MMN. The two groups (AVS and AV were differently affected by the training. The results suggest that multisensory training alters the function of multisensory structures, and not the uni-sensory ones along with their interconnections, and thus provide an answer to an important question presented by cognitive models of multisensory training.

  17. Lifetime Reliability Estimate and Extreme Permanent Deformations of Randomly Excited Elasto-Plastic Structures

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.; Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1983-01-01

    plastic deformation during several loadings can be modelled as a filtered Poisson process. Using the Markov property of this quantity the considered first-passage problem as well as the related extreme distribution problems are then solved numerically, and the results are compared to simulation studies.......A method is presented for life-time reliability' estimates of randomly excited yielding systems, assuming the structure to be safe, when the plastic deformations are confined below certain limits. The accumulated plastic deformations during any single significant loading history are considered...

  18. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  19. Elastic-plastic creep response of structures under composite time history

    Energy Technology Data Exchange (ETDEWEB)

    Zudans, Z [Franklin Inst. Research Labs., Philadelphia, Pa. (USA)

    1975-12-01

    High temperature nuclear reactor components are subject to a complex history of thermal and mechanical loading cycles. To evaluate the adequacy of such components, detailed information on the accumulated inelastic strains and strain cycling is required. This paper presents the theory, describes efficient numerical techniques accounting for plasticity, creep and overall equilibrium, describes the overall structure of the resulting computer program, and demonstrates the capability of the analysis method on a real three-dimensional structure. The new results of this work are the efficient handling of an arbitrary load history, introduction of the 'plastic stress' concept for inelastic computation, novel implementation of classical plasticity with recognition of incrementation conditions for the kinematic hardening, use of the load incrementation algorithm based on the 'plastic stress' concept, and development of a computer code capable of solving practical three-dimensional problems.

  20. Elastic-plastic creep response of structures under composite time history

    International Nuclear Information System (INIS)

    Zudans, Z.

    1975-01-01

    High temperature nuclear reactor components are subject to a complex history of thermal and mechanical loading cycles. To evaluate the adequacy of such components, detailed information on the accumulated inelastic strains and strain cycling is required. This paper presents the theory, describes efficient numerical techniques accounting for plasticity, creep and overall equilibrium, describes the overall structure of the resulting computer program, and demonstrates the capability of the analysis method on a real three-dimensional structure. The new results of this work are the efficient handling of an arbitrary load history, introduction of the 'plastic stress' concept for inelastic computation, novel implementation of classical plasticity with recognition of incrementation conditions for the kinematic hardening, use of the load incrementation algorithm based on the 'plastic stress' concept, and development of a computer code capable of solving practical three-dimensional problems. (Auth.)

  1. Evaluation of plastic collapse behavior for multiple cracked structures

    International Nuclear Information System (INIS)

    Moon, Seong In; Chang, Yoon Suk; Kim, Young Jin; Lee, Jin Ho; Song, Myung Ho; Choi, Young Hwan; Hwang, Seong Sik

    2004-01-01

    Until now, the 40% of wall thickness criterion, which is generally used for the plugging of steam generator tubes, has been applied only to a single cracked geometry. In the previous study by the authors, a total number of 9 local failure prediction models were introduced to estimate the coalescence load of two collinear through-wall cracks and, then, the reaction force model and plastic zone contact model were selected as the optimum ones. The objective of this study is to estimate the coalescence load of two collinear through-wall cracks in steam generator tube by using the optimum local failure prediction models. In order to investigate the applicability of the optimum local failure prediction models, a series of plastic collapse tests and corresponding finite element analyses for two collinear through-wall cracks in steam generator tube were carried out. Thereby, the applicability of the optimum local failure prediction models was verified and, finally, a coalescence evaluation diagram which can be used to determine whether the adjacent cracks detected by NDE coalesce or not has been developed

  2. Effect of the conditions of prepreg preparation on the strength of structural plastics

    Science.gov (United States)

    Zaborskaya, L. V.; Yurkevich, O. R.

    1995-05-01

    A study is made of the effect of the temperature and duration of heat treatment of polymer composite prepregs on their strength. It is established that heat treatment under conditions ensuring close to maximal adhesive interaction between the components of the prepreg and subsequent shaping makes it possible to more than double the strength of the plastic (Table 1), A new approach is proposed to optimizing the conditions of formation of structural plastics.

  3. The role of structural characteristics in problem video game playing: a review

    OpenAIRE

    King, DL; Delfabbro, PH; Griffiths, MD

    2010-01-01

    The structural characteristics of video games may play an important role in explaining why some people play video games to excess. This paper provides a review of the literature on structural features of video games and the psychological experience of playing video games. The dominant view of the appeal of video games is based on operant conditioning theory and the notion that video games satisfy various needs for social interaction and belonging. However, there is a lack of experimental and ...

  4. Perinatal fluoxetine effects on social play, the HPA system, and hippocampal plasticity in pre-adolescent male and female rats: Interactions with pre-gestational maternal stress.

    Science.gov (United States)

    Gemmel, Mary; Hazlett, Mariah; Bögi, Eszter; De Lacalle, Sonsoles; Hill, Lesley A; Kokras, Nikolaos; Hammond, Geoffrey L; Dalla, Christina; Charlier, Thierry D; Pawluski, Jodi L

    2017-10-01

    Selective serotonin reuptake inhibitor medications (SSRIs) are the first lines of treatment for maternal affective disorders, and are prescribed to up to 10% of pregnant women. Concern has been raised about how perinatal exposure to these medications affect offspring neurobehavioral outcomes, particularly those related to social interactions, as recent research has reported conflicting results related to autism spectrum disorder (ASD) risk in children prenatally exposed to SSRIs. Therefore, the aim of this work was to investigate the effects of perinatal exposure to the SSRI fluoxetine on social play behaviors and the hypothalamic pituitary adrenal system, using a model of pre-gestational maternal stress. We also investigated synaptic proteins in the CA2, CA3, and dentate gyrus of the hippocampus, as well as number of immature neurons in the granule cell layer, as both measures of plasticity in the hippocampus have been linked to social behaviors. In pre-adolescent male and female Sprague-Dawley rat offspring, main findings show that perinatal fluoxetine prevents the negative effect of maternal stress on sibling play behavior. However, perinatal fluoxetine increased social aggressive play with a novel conspecific in both sexes and decreased time grooming a novel conspecific in males only. Perinatal fluoxetine also increased serum corticosteroid binding globulin levels, 5-HT levels in the hippocampus, and pre-synaptic density assessed via synaptophysin in the dentate gyrus. Social interaction was significantly correlated with changes in plasticity in the CA2 region of the hippocampus. Pre-gestational maternal stress exposure resulted in significantly decreased rates of hippocampal neurogenesis and synaptophysin density in the dentate gyrus of pre-adolescent males, but not females. Together, these results further characterize the role of perinatal SSRIs, maternal stress prior to conception, and sex/gender on developing social behaviors and related plasticity in the

  5. A unified approach to the analysis and design of elasto-plastic structures with mechanical contact

    Science.gov (United States)

    Bendsoe, Martin P.; Olhoff, Niels; Taylor, John E.

    1990-01-01

    With structural design in mind, a new unified variational model has been developed which represents the mechanics of deformation elasto-plasticity with unilateral contact conditions. For a design problem formulated as maximization of the load carrying capacity of a structure under certain constraints, the unified model allows for a simultaneous analysis and design synthesis for a whole range of mechanical behavior.

  6. Dense-body aggregates as plastic structures supporting tension in smooth muscle cells.

    Science.gov (United States)

    Zhang, Jie; Herrera, Ana M; Paré, Peter D; Seow, Chun Y

    2010-11-01

    The wall of hollow organs of vertebrates is a unique structure able to generate active tension and maintain a nearly constant passive stiffness over a large volume range. These properties are predominantly attributable to the smooth muscle cells that line the organ wall. Although smooth muscle is known to possess plasticity (i.e., the ability to adapt to large changes in cell length through structural remodeling of contractile apparatus and cytoskeleton), the detailed structural basis for the plasticity is largely unknown. Dense bodies, one of the most prominent structures in smooth muscle cells, have been regarded as the anchoring sites for actin filaments, similar to the Z-disks in striated muscle. Here, we show that the dense bodies and intermediate filaments formed cable-like structures inside airway smooth muscle cells and were able to adjust the cable length according to cell length and tension. Stretching the muscle cell bundle in the relaxed state caused the cables to straighten, indicating that these intracellular structures were connected to the extracellular matrix and could support passive tension. These plastic structures may be responsible for the ability of smooth muscle to maintain a nearly constant tensile stiffness over a large length range. The finding suggests that the structural plasticity of hollow organs may originate from the dense-body cables within the smooth muscle cells.

  7. Constitutive modeling and structural analysis considering simultaneous phase transformation and plastic yield in shape memory alloys

    Science.gov (United States)

    Hartl, D. J.; Lagoudas, D. C.

    2009-10-01

    The new developments summarized in this work represent both theoretical and experimental investigations of the effects of plastic strain generation in shape memory alloys (SMAs). Based on the results of SMA experimental characterization described in the literature and additional testing described in this work, a new 3D constitutive model is proposed. This phenomenological model captures both the conventional shape memory effects of pseudoelasticity and thermal strain recovery, and additionally considers the initiation and evolution of plastic strains. The model is numerically implemented in a finite element framework using a return mapping algorithm to solve the constitutive equations at each material point. This combination of theory and implementation is unique in its ability to capture the simultaneous evolution of recoverable transformation strains and irrecoverable plastic strains. The consideration of isotropic and kinematic plastic hardening allows the derivation of a theoretical framework capturing the interactions between irrecoverable plastic strain and recoverable strain due to martensitic transformation. Further, the numerical integration of the constitutive equations is formulated such that objectivity is maintained for SMA structures undergoing moderate strains and large displacements. The implemented model has been used to perform 3D analysis of SMA structural components under uniaxial and bending loads, including a case of local buckling behavior. Experimentally validated results considering simultaneous transformation and plasticity in a bending member are provided, illustrating the predictive accuracy of the model and its implementation.

  8. Constitutive modeling and structural analysis considering simultaneous phase transformation and plastic yield in shape memory alloys

    International Nuclear Information System (INIS)

    Hartl, D J; Lagoudas, D C

    2009-01-01

    The new developments summarized in this work represent both theoretical and experimental investigations of the effects of plastic strain generation in shape memory alloys (SMAs). Based on the results of SMA experimental characterization described in the literature and additional testing described in this work, a new 3D constitutive model is proposed. This phenomenological model captures both the conventional shape memory effects of pseudoelasticity and thermal strain recovery, and additionally considers the initiation and evolution of plastic strains. The model is numerically implemented in a finite element framework using a return mapping algorithm to solve the constitutive equations at each material point. This combination of theory and implementation is unique in its ability to capture the simultaneous evolution of recoverable transformation strains and irrecoverable plastic strains. The consideration of isotropic and kinematic plastic hardening allows the derivation of a theoretical framework capturing the interactions between irrecoverable plastic strain and recoverable strain due to martensitic transformation. Further, the numerical integration of the constitutive equations is formulated such that objectivity is maintained for SMA structures undergoing moderate strains and large displacements. The implemented model has been used to perform 3D analysis of SMA structural components under uniaxial and bending loads, including a case of local buckling behavior. Experimentally validated results considering simultaneous transformation and plasticity in a bending member are provided, illustrating the predictive accuracy of the model and its implementation

  9. Collapse Probability for Elasto-Plastic Beam Structures

    DEFF Research Database (Denmark)

    Delmar, M.V.; Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In present design practice considerations on structural safety are usually concentrated on failure states corresponding to initial failure of an element. For a frame structure that means failure of a cross-section of the structure. Sufficient reliability with respect to this limit state is expect...

  10. Learning Structure of Sensory Inputs with Synaptic Plasticity Leads to Interference

    Directory of Open Access Journals (Sweden)

    Joseph eChrol-Cannon

    2015-08-01

    Full Text Available Synaptic plasticity is often explored as a form of unsupervised adaptationin cortical microcircuits to learn the structure of complex sensoryinputs and thereby improve performance of classification and prediction. The question of whether the specific structure of the input patterns is encoded in the structure of neural networks has been largely neglected. Existing studies that have analyzed input-specific structural adaptation have used simplified, synthetic inputs in contrast to complex and noisy patterns found in real-world sensory data.In this work, input-specific structural changes are analyzed forthree empirically derived models of plasticity applied to three temporal sensory classification tasks that include complex, real-world visual and auditory data. Two forms of spike-timing dependent plasticity (STDP and the Bienenstock-Cooper-Munro (BCM plasticity rule are used to adapt the recurrent network structure during the training process before performance is tested on the pattern recognition tasks.It is shown that synaptic adaptation is highly sensitive to specific classes of input pattern. However, plasticity does not improve the performance on sensory pattern recognition tasks, partly due to synaptic interference between consecutively presented input samples. The changes in synaptic strength produced by one stimulus are reversed by thepresentation of another, thus largely preventing input-specific synaptic changes from being retained in the structure of the network.To solve the problem of interference, we suggest that models of plasticitybe extended to restrict neural activity and synaptic modification to a subset of the neural circuit, which is increasingly found to be the casein experimental neuroscience.

  11. Parameter Identification of Piecewise Linear Plasticity Metal Models Used in Numerical Modeling of Structures Under Plastic Deformation and Failure

    Directory of Open Access Journals (Sweden)

    A. V. Shmeliov

    2016-01-01

    Full Text Available The article describes the models of metallic materials used in the calculation of deformation and destruction of engineering structures. The reliability of material models can adequately assess the strength characteristics of the designs of new technology in its designing and certification.The article deals with contingencies and true mechanical properties of materials and presents equations of their relationship. It notes that in the software systems mechanical characteristics of materials are given in the true sense.The paper considers the linear and exponential models of materials, their characteristics, and methods to implement them. It considers the models of Johnson-Cook Steinberg-Guinan, Zerilli-Armstrong, Cowper-Symonds, Gurson-Tvergaard that take into account the strain rate and temperature of the material. Describes their applications, advantages and disadvantages. Considers single- and multi-parameter criteria of materials fracture, the prospects for their use. Gives a rational justification for using a piecewise linear plasticity material model *MAT_PIECEWISE_LINEAR_PLASTICITY (024, LS-DYNA software package for the engineering industry, and presents its main parameters.A technique to identify parameters of piecewise linear plasticity metal material models has been developed. The technique consists of the stages, based on the equations of transition from the conventional stress and strain values to the true ones. Taking into consideration the stressstrain state in the neck of the sample is a distinctive feature of the technique.Tensile tests of the round material samples have been conducted. To test the developed technique in the software package ANSYS LS-DYNA PC have been made tensile sample modeling and results comparison to show high convergence.Further improvement of the technique can be achieved through the development of a statistical approach to the analysis of the results of a series of tests. This will allow a kind of

  12. High affinity antigen recognition of the dual specific variants of herceptin is entropy-driven in spite of structural plasticity.

    Directory of Open Access Journals (Sweden)

    Jenny Bostrom

    Full Text Available The antigen-binding site of Herceptin, an anti-human Epidermal Growth Factor Receptor 2 (HER2 antibody, was engineered to add a second specificity toward Vascular Endothelial Growth Factor (VEGF to create a high affinity two-in-one antibody bH1. Crystal structures of bH1 in complex with either antigen showed that, in comparison to Herceptin, this antibody exhibited greater conformational variability, also called "structural plasticity". Here, we analyzed the biophysical and thermodynamic properties of the dual specific variants of Herceptin to understand how a single antibody binds two unrelated protein antigens. We showed that while bH1 and the affinity-improved bH1-44, in particular, maintained many properties of Herceptin including binding affinity, kinetics and the use of residues for antigen recognition, they differed in the binding thermodynamics. The interactions of bH1 and its variants with both antigens were characterized by large favorable entropy changes whereas the Herceptin/HER2 interaction involved a large favorable enthalpy change. By dissecting the total entropy change and the energy barrier for dual interaction, we determined that the significant structural plasticity of the bH1 antibodies demanded by the dual specificity did not translate into the expected increase of entropic penalty relative to Herceptin. Clearly, dual antigen recognition of the Herceptin variants involves divergent antibody conformations of nearly equivalent energetic states. Hence, increasing the structural plasticity of an antigen-binding site without increasing the entropic cost may play a role for antibodies to evolve multi-specificity. Our report represents the first comprehensive biophysical analysis of a high affinity dual specific antibody binding two unrelated protein antigens, furthering our understanding of the thermodynamics that drive the vast antigen recognition capacity of the antibody repertoire.

  13. Stochastic Finite Element Analysis of Non-Linear Structures Modelled by Plasticity Theory

    DEFF Research Database (Denmark)

    Frier, Christian; Sørensen, John Dalsgaard

    2003-01-01

    A Finite Element Reliability Method (FERM) is introduced to perform reliability analyses on two-dimensional structures in plane stress, modeled by non-linear plasticity theory. FERM is a coupling between the First Order Reliability Method (FORM) and the Finite Element Method (FEM). FERM can be us...

  14. Learning to Perceive Structure from Motion and Neural Plasticity in Patients with Alzheimer's Disease

    Science.gov (United States)

    Kim, Nam-Gyoon; Park, Jong-Hee

    2010-01-01

    Recent research has demonstrated that Alzheimer's disease (AD) affects the visual sensory pathways, producing a variety of visual deficits, including the capacity to perceive structure-from-motion (SFM). Because the sensory areas of the adult brain are known to retain a large degree of plasticity, the present study was conducted to explore whether…

  15. Hippocampal Structural Plasticity Accompanies the Resulting Contextual Fear Memory Following Stress and Fear Conditioning

    Science.gov (United States)

    Giachero, Marcelo; Calfa, Gaston D.; Molina, Victor A.

    2013-01-01

    The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to…

  16. Validity of a structured method of selecting abstracts for a plastic surgical scientific meeting

    NARCIS (Netherlands)

    van der Steen, LPE; Hage, JJ; Kon, M; Monstrey, SJ

    In 1999, the European Association of Plastic Surgeons accepted a structured method to assess and select the abstracts that are submitted for its yearly scientific meeting. The two criteria used to evaluate whether such a selection method is accurate were reliability and validity. The authors

  17. Consideration of plasticity within the design of timber structures due to connection ductility

    NARCIS (Netherlands)

    Brühl, F.; Kuhlmann, U.; Jorissen, A.J.M.

    2011-01-01

    The plastic behavior of fasteners in timber structures has gained more and more interest within recent years. In particular, dowel type fasteners show a significant ductile behavior if a certain embedded length of the dowel is ensured. The embedded length is either found by using the formulas based

  18. Effects of plasticization and shear stress on phase structure development and properties of soy protein blends.

    Science.gov (United States)

    Chen, Feng; Zhang, Jinwen

    2010-11-01

    In this study, soy protein concentrate (SPC) was used as a plastic component to blend with poly(butylene adipate-co-terephthalate) (PBAT). Effects of SPC plasticization and blend composition on its deformation during mixing were studied in detail. Influence of using water as the major plasticizer and glycerol as the co-plasticizer on the deformation of the SPC phase during mixing was explored. The effect of shear stress, as affected by SPC loading level, on the phase structure of SPC in the blends was also investigated. Quantitative analysis of the aspect ratio of SPC particles was conducted by using ImageJ software, and an empirical model predicting the formation of percolated structure was applied. The experimental results and the model prediction showed a fairly good agreement. The experimental results and statistic analysis suggest that both SPC loading level and its water content prior to compounding had significant influences on development of the SPC phase structure and were correlated in determining the morphological structures of the resulting blends. Consequently, physical and mechanical properties of the blends greatly depended on the phase morphology and PBAT/SPC ratio of the blends.

  19. Binocular vision in amblyopia: structure, suppression and plasticity.

    Science.gov (United States)

    Hess, Robert F; Thompson, Benjamin; Baker, Daniel H

    2014-03-01

    The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cortex and, on the basis of initial data, appear to improve both binocular and monocular visual function, even in adults with amblyopia. The aim of this review is to provide an overview of recent studies that have investigated the structure, measurement and treatment of binocular vision in observers with strabismic, anisometropic and mixed amblyopia. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

  20. Structural plasticity of the N-terminal capping helix of the TPR domain of kinesin light chain.

    Directory of Open Access Journals (Sweden)

    The Quyen Nguyen

    Full Text Available Kinesin1 plays a major role in neuronal transport by recruiting many different cargos through its kinesin light chain (KLC. Various structurally unrelated cargos interact with the conserved tetratricopeptide repeat (TPR domain of KLC. The N-terminal capping helix of the TPR domain exhibits an atypical sequence and structural features that may contribute to the versatility of the TPR domain to bind different cargos. We determined crystal structures of the TPR domain of both KLC1 and KLC2 encompassing the N-terminal capping helix and show that this helix exhibits two distinct and defined orientations relative to the rest of the TPR domain. Such a difference in orientation gives rise, at the N-terminal part of the groove, to the formation of one hydrophobic pocket, as well as to electrostatic variations at the groove surface. We present a comprehensive structural analysis of available KLC1/2-TPR domain structures that highlights that ligand binding into the groove can be specific of one or the other N-terminal capping helix orientations. Further, structural analysis reveals that the N-terminal capping helix is always involved in crystal packing contacts, especially in a TPR1:TPR1' contact which highlights its propensity to be a protein-protein interaction site. Together, these results underline that the structural plasticity of the N-terminal capping helix might represent a structural determinant for TPR domain structural versatility in cargo binding.

  1. Binocular vision in amblyopia : structure, suppression and plasticity

    OpenAIRE

    Hess, Robert F; Thompson, Benjamin; Baker, Daniel Hart

    2014-01-01

    The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cor...

  2. Micro structure processing on plastics by accelerated hydrogen molecular ions

    Science.gov (United States)

    Hayashi, H.; Hayakawa, S.; Nishikawa, H.

    2017-08-01

    A proton has 1836 times the mass of an electron and is the lightest nucleus to be used for accelerator in material modification. We can setup accelerator with the lowest acceleration voltage. It is preferable characteristics of Proton Beam Writer (PBW) for industrial applications. On the contrary ;proton; has the lowest charge among all nuclei and the potential impact to material is lowest. The object of this research is to improve productivity of the PBW for industry application focusing on hydrogen molecular ions. These ions are generated in the same ion source by ionizing hydrogen molecule. There is no specific ion source requested and it is suitable for industrial use. We demonstrated three dimensional (3D) multilevel micro structures on polyester base FPC (Flexible Printed Circuits) using proton, H2+ and H3+. The reactivity of hydrogen molecular ions is much higher than that of proton and coincident with the level of expectation. We can apply this result to make micro devices of 3D multilevel structures on FPC.

  3. Elastic-plastic-creep response of structures under composite time history of loadings

    International Nuclear Information System (INIS)

    Zudans, Z.

    1975-01-01

    High temperature nuclear reactor components are subject to a complex history of thermal and mechanical loading cycles. To evaluate the adequacy of such components, detailed information on the accumulated inelastic strains and strain cycling is required. This work derives the theory, develops efficient numerical techniques accounting for plasticity, creep and overall equilibrium, describes the overall structure of the resulting computer program, and demonstrates the capability of this analysis on a real structure. (Auth.)

  4. The elastic-plastic failure assessment diagram of surface cracked structure

    International Nuclear Information System (INIS)

    Ning, J.; Gao, Q.

    1987-01-01

    The simplified NLSM is able to calculate the EPFM parameters and failure assessment curve for the surface cracked structure correctly and conveniently. The elastic-plastic failure assessment curve of surface crack is relevant to crack geometry, loading form and material deformation behaviour. It is necessary to construct the EPFM failure assessment curve of the surface crack for the failure assessment of surface cracked structure. (orig./HP)

  5. Functional Plasticity in the Absence of Structural Change.

    Science.gov (United States)

    Krasovsky, Tal; Landa, Jana; Bar, Orly; Jaana, Ahonniska-Assa; Livny, Abigail; Tsarfaty, Galia; Silberg, Tamar

    2017-04-01

    This work presents a case of a young woman with apraxia and a severe body scheme disorder, 10 years after a childhood frontal and occipitoparietal brain injury. Despite specific limitations, she is independent in performing all activities of daily living. A battery of tests was administered to evaluate praxis and body representations. Specifically, the Hand Laterality Test was used to compare RS's dynamic body representation to that of healthy controls (N = 14). Results demonstrated RS's severe praxis impairment, and the Hand Laterality Test revealed deficits in accuracy and latency of motor imagery, suggesting a significant impairment in dynamic body representation. However, semantic and structural body representations were intact. These results, coupled with frequent use of verbalizations as a strategy, suggest a possible ventral compensatory mechanism (top-down processing) for dorsal stream deficits, which may explain RS's remarkable recovery of activities of daily living. The link between praxis and dynamic body representation is discussed.

  6. Role of synaptic structural plasticity in impairments of spatial learning and memory induced by developmental lead exposure in Wistar rats.

    Directory of Open Access Journals (Sweden)

    Yongmei Xiao

    Full Text Available Lead (Pb is found to impair cognitive function. Synaptic structural plasticity is considered to be the physiological basis of synaptic functional plasticity and has been recently found to play important roles in learning and memory. To study the effect of Pb on spatial learning and memory at different developmental stages, and its relationship with alterations of synaptic structural plasticity, postnatal rats were randomly divided into three groups: Control; Pre-weaning Pb (Parents were exposed to 2 mM PbCl2 3 weeks before mating until weaning of pups; Post-weaning Pb (Weaned pups were exposed to 2 mM PbCl2 for 9 weeks. The spatial learning and memory of rats was measured by Morris water maze (MWM on PND 85-90. Rat pups in Pre-weaning Pb and Post-weaning Pb groups performed significantly worse than those in Control group (p<0.05. However, there was no significant difference in the performance of MWM between the two Pb-exposure groups. Before MWM (PND 84, the number of neurons and synapses significantly decreased in Pre-weaning Pb group, but not in Post-weaning Pb group. After MWM (PND 91, the number of synapses in Pre-weaning Pb group increased significantly, but it was still less than that of Control group (p<0.05; the number of synapses in Post-weaning Pb group was also less than that of Control group (p<0.05, although the number of synapses has no differences between Post-weaning Pb and Control groups before MWM. In both Pre-weaning Pb and Post-weaning Pb groups, synaptic structural parameters such as thickness of postsynaptic density (PSD, length of synaptic active zone and synaptic curvature increased significantly while width of synaptic cleft decreased significantly compared to Control group (p<0.05. Our data demonstrated that both early and late developmental Pb exposure impaired spatial learning and memory as well as synaptic structural plasticity in Wistar rats.

  7. I Wanna Play Too: Factors Related to Changes in Social Behavior for Children with and without Autism Spectrum Disorder after Implementation of a Structured Outdoor Play Curriculum

    Science.gov (United States)

    Morrier, Michael J.; Ziegler, Sonja M. T.

    2018-01-01

    Children with autism spectrum disorder (ASD) have difficulties interacting with same-aged peers during unstructured play (e.g., on the playground). Thirty-five toddler and preschool children with and without ASD participated in a structured 15-min outdoor play curriculum. The intervention, "the Buddy Game," used familiar songs, movement,…

  8. Molecular studies and plastic optical fiber device structures for nonlinear optical applications

    Science.gov (United States)

    Dirk, Carl W.; Nagarur, Aruna R.; Lu, Jin J.; Zhang, Lixia; Kalamegham, Priya; Fonseca, Joe; Gopalan, Saytha; Townsend, Scott; Gonzalez, Gabriel; Craig, Patrick; Rosales, Monica; Green, Leslie; Chan, Karen; Twieg, Robert J.; Ermer, Susan P.; Leung, Doris S.; Lovejoy, Steven M.; Lacroix, Suzanne; Godbout, Nicolas; Monette, Etienne

    1995-10-01

    Summarized are two project areas: First, the development of a quantitative structure property relationship for analyzing thermal decomposition differential scanning calorimetry data of electro-optic dyes is presented. The QSPR relationship suggest that thermal decomposition can be effectively correlated with structure by considering the kinds of atoms, their hybridization, and their nearest neighbor bonded atoms. Second, the simple preparation of clad plastic optical fibers (POF) is discussed with the intention of use for nonlinear optical applications. We discuss preparation techniques for single core and multiple core POF, and present some recent data on index profiles and the optimization of thermal stability in acrylate-based POF structures.

  9. Semantic modeling of the structural and process entities during plastic deformation of crystals and rocks

    Science.gov (United States)

    Babaie, Hassan; Davarpanah, Armita

    2016-04-01

    We are semantically modeling the structural and dynamic process components of the plastic deformation of minerals and rocks in the Plastic Deformation Ontology (PDO). Applying the Ontology of Physics in Biology, the PDO classifies the spatial entities that participate in the diverse processes of plastic deformation into the Physical_Plastic_Deformation_Entity and Nonphysical_Plastic_Deformation_Entity classes. The Material_Physical_Plastic_Deformation_Entity class includes things such as microstructures, lattice defects, atoms, liquid, and grain boundaries, and the Immaterial_Physical_Plastic_Deformation_Entity class includes vacancies in crystals and voids along mineral grain boundaries. The objects under the many subclasses of these classes (e.g., crystal, lattice defect, layering) have spatial parts that are related to each other through taxonomic (e.g., Line_Defect isA Lattice_Defect), structural (mereological, e.g., Twin_Plane partOf Twin), spatial-topological (e.g., Vacancy adjacentTo Atom, Fluid locatedAlong Grain_Boundary), and domain specific (e.g., displaces, Fluid crystallizes Dissolved_Ion, Void existsAlong Grain_Boundary) relationships. The dynamic aspect of the plastic deformation is modeled under the dynamical Process_Entity class that subsumes classes such as Recrystallization and Pressure_Solution that define the flow of energy amongst the physical entities. The values of the dynamical state properties of the physical entities (e.g., Chemical_Potential, Temperature, Particle_Velocity) change while they take part in the deformational processes such as Diffusion and Dislocation_Glide. The process entities have temporal parts (phases) that are related to each other through temporal relations such as precedes, isSubprocessOf, and overlaps. The properties of the physical entities, defined under the Physical_Property class, change as they participate in the plastic deformational processes. The properties are categorized into dynamical, constitutive

  10. Structural conditions of maximal plasticity of two-phase metal materials

    International Nuclear Information System (INIS)

    Movchan, B.A.

    1975-01-01

    Analysis is given of experimental values of the strength and plasticity of iron- and tungsten-based two-phase materials with the regulated amount of the second phase and the grain size. Specimens in the form of a 120 mm x 200 mm sheet with a thickness of 0.8-1.2 mm are prepared by means of the electron beam evaporation technique and subsequent condensation of the materials on a preheated support. The variable content of the second phase along the sheet in the range 0.5 volume per cent and more than a 10-fold change in the grain size of the metallic matrix are attained by a simultaneous evaporation of pure metal (99.98 per cent) and nonlmetallic material-niobium carbide or zirconium dioxide ZrO 2 -from two separate sources. The content of arbitrarily distributed spherical particles of the second phase corresponding to a maximum of the plasticity depends only on the structural parameter - the d/D ratio. The absolute falue of the plasticity and its dependence on the temperature is a complex function of many variables - mechanical properties of particles and the matrix, peculiarities of interphase interaction on the boundary particle - matrix, the size of particles, the rate of plastic deformation and relaxation processes

  11. Homeostatic structural plasticity can account for topology changes following deafferentation and focal stroke.

    Science.gov (United States)

    Butz, Markus; Steenbuck, Ines D; van Ooyen, Arjen

    2014-01-01

    After brain lesions caused by tumors or stroke, or after lasting loss of input (deafferentation), inter- and intra-regional brain networks respond with complex changes in topology. Not only areas directly affected by the lesion but also regions remote from the lesion may alter their connectivity-a phenomenon known as diaschisis. Changes in network topology after brain lesions can lead to cognitive decline and increasing functional disability. However, the principles governing changes in network topology are poorly understood. Here, we investigated whether homeostatic structural plasticity can account for changes in network topology after deafferentation and brain lesions. Homeostatic structural plasticity postulates that neurons aim to maintain a desired level of electrical activity by deleting synapses when neuronal activity is too high and by providing new synaptic contacts when activity is too low. Using our Model of Structural Plasticity, we explored how local changes in connectivity induced by a focal loss of input affected global network topology. In accordance with experimental and clinical data, we found that after partial deafferentation, the network as a whole became more random, although it maintained its small-world topology, while deafferentated neurons increased their betweenness centrality as they rewired and returned to the homeostatic range of activity. Furthermore, deafferentated neurons increased their global but decreased their local efficiency and got longer tailed degree distributions, indicating the emergence of hub neurons. Together, our results suggest that homeostatic structural plasticity may be an important driving force for lesion-induced network reorganization and that the increase in betweenness centrality of deafferentated areas may hold as a biomarker for brain repair.

  12. Computer simulation of model cohesive powders: Plastic consolidation, structural changes and elasticity under isotropic loads

    OpenAIRE

    Gilabert, Francisco; Roux, Jean-Noël; Castellanos, Antonio

    2008-01-01

    International audience; The quasistatic behavior of a simple 2D model of a cohesive powder under isotropic loads is investigated by Discrete Element simulations. The loose packing states, as studied in a previous paper, undergo important structural changes under growing confining pressure P, while solid fraction \\Phi irreversibly increases by large amounts. The system state goes through three stages, with different forms of the plastic consolidation curve \\Phi(P*), under growing reduced press...

  13. Significance of Objective Structured Clinical Examinations to Plastic Surgery Residency Training.

    Science.gov (United States)

    Simmons, Brian J; Zoghbi, Yasmina; Askari, Morad; Birnbach, David J; Shekhter, Ilya; Thaller, Seth R

    2017-09-01

    Objective structured clinical examinations (OSCEs) have proven to be a powerful tool. They possess more than a 30-year track record in assessing the competency of medical students, residents, and fellows. Objective structured clinical examinations have been used successfully in a variety of medical specialties, including surgery. They have recently found their way into the subspecialty of plastic surgery. This article uses a systematic review of the available literature on OSCEs and their recent use in plastic surgery. It incorporates survey results assessing program directors' views on the use of OSCEs. Approximately 40% of programs surveyed use OSCEs to assess the Accreditation Council for Graduate Medical Education core competencies. We found that 40% use OSCEs to evaluate specific plastic surgery milestones. Objective structured clinical examinations are usually performed annually. They cost anywhere between $100 and more than $1000 per resident. Four milestones giving residents the most difficulties on OSCEs were congenital anomalies, noncancer breast surgery, breast reconstruction, and practice-based learning and improvement. It was determined that challenges with milestones were due to lack of adequate general knowledge and surgical ward patient care, as well as deficits in professionalism and system-based problems. Programs were able to remediate weakness found by OSCEs using a variety of methods. Objective structured clinical examinations offer a unique tool to objectively assess the proficiency of residents in key areas of the Accreditation Council for Graduate Medical Education core competencies. In addition, they can be used to assess the specific milestones that plastic surgery residents must meet. This allows programs to identify and improve identified areas of weakness.

  14. Neural-Fitted TD-Leaf Learning for Playing Othello With Structured Neural Networks

    NARCIS (Netherlands)

    van den Dries, Sjoerd; Wiering, Marco A.

    This paper describes a methodology for quickly learning to play games at a strong level. The methodology consists of a novel combination of three techniques, and a variety of experiments on the game of Othello demonstrates their usefulness. First, structures or topologies in neural network

  15. Structural defects in natural plastically deformed diamonds: Evidence from EPR spectroscopy

    Science.gov (United States)

    Mineeva, R. M.; Titkov, S. V.; Speransky, A. V.

    2009-06-01

    Structural defects formed as a result of plastic deformation in natural diamond crystals have been studied by EPR spectroscopy. The spectra of brown, pink-brown, black-brown, pink-purple, and gray plastically deformed diamonds of type Ia from deposits in Yakutia and the Urals were recorded. The results of EPR spectroscopy allowed us to identify various deformation centers in the structure of natural diamonds and to show that nitrogen centers were transformed under epigenetic mechanical loading. Abundant A centers, consisting of two isomorphic nitrogen atoms located in neighboring structural sites, were destroyed as a result of this process to form a series of N1, N4, W7, M2, and M3 nitrogen centers. Such centers are characterized by an anisotropic spatial distribution and a positive charge, related to the mechanism of their formation. In addition, N2 centers (probably, deformation-produced dislocations decorated by nitrogen) were formed in all plastically deformed diamonds and W10 and W35 centers (the models have not been finally ascertained) were formed in some of them. It has been established that diamonds with various types of deformation-induced color contain characteristic associations of these deformation centers. The diversity of associations of deformation centers indicates appreciable variations in conditions of disintegration of deep-seated rocks, transfer of diamonds to the Earth’s surface, and formation of kimberlitic deposits. Depending on the conditions of mechanical loading, the diamond crystals were plastically deformed by either dislocation gliding or mechanical twinning. Characteristic features of plastic deformation by dislocation gliding are the substantial prevalence of the N2 centers over other deformation centers and the occurrence of the high-spin W10 and W35 centers. The attributes of less frequent plastic deformation by mechanical twinning are unusual localization of the M2 centers and, in some cases, the N1 centers in microtwinned

  16. Vibration technique for non-destructive testing of carbon fiber reinforced plastic structures

    International Nuclear Information System (INIS)

    Miller, W.G.

    1982-01-01

    For nondestructive testing of structures of KFK (carbon fiber reinforced plastics) Adams and a group at the English University of Bristol, Department of Mechanical Engineering have developed a vibrational testing method. It is based on the fact that the decreasing self-oscillations of a structure can be measured in connection with a dynamical analysis at only one particular location of that structure. This way a damage can be localized and be quantized rawly. The mathematical model is simple and for every tested structure only one analysis is needed. Many kinds of damages in structures can be determined and reproduced especially in structures that represent typical cases of application of KFK in air and aerospace industry. (orig.) [de

  17. Hydraulic pressure pulses with elastic and plastic structural flexibility: test and analysis (LWBR Development Program)

    International Nuclear Information System (INIS)

    Schwirian, R.E.

    1978-03-01

    Pressure pulse tests were conducted with a flexible test section in a test vessel filled with room temperature water. The pressure pulses were generated with a drop hammer and piston pulse generator and were of a sufficient magnitude to cause plastic deformation of the test section. Because of the strong pressure relief effect of the deforming test section, pressure pulse magnitudes were below 265 psig in magnitude and had durations of 50 to 55 msecs. Calculations performed with the FLASH-35 bi-linear hysteresis model of structural deformation show good agreement with experiment. In particular, FLASH 35 adequately predicts the decrease in peak pressure and the increase in pulse duration due to elastic and plastic deformation of the test section. Predictions of flexible member motion are good, but are less satisfactory than the pressure pulse results due to uncertainties in the values of yield point and beyond yield stiffness used to model the various flexible members. Coupled with this is a strong sensitivity of the FLASH 35 predictions to the values of yield point and beyond yield stiffness chosen for the various flexible members. The test data versus calculation comparisons presented here provide preliminary qualification for FLASH 35 calculations of transient hydraulic pressures and pressure differentials in the presence of flexible structural members which deform both elastically and plastically

  18. Modeling elasto-plastic behavior of polycrystalline grain structure of steels at mesoscopic level

    International Nuclear Information System (INIS)

    Kovac, Marko; Cizelj, Leon

    2005-01-01

    The multiscale model is proposed to explicitly account for the inhomogeneous structure of polycrystalline materials. Grains and grain boundaries are modeled explicitly using Voronoi tessellation. The constitutive model of crystal grains utilizes anisotropic elasticity and crystal plasticity. Commercially available finite element code is applied to solve the boundary value problem defined at the macroscopic scale. No assumption regarding the distribution of the mesoscopic strain and stress fields is used, apart the finite element discretization. The proposed model is then used to estimate the minimum size of polycrystalline aggregate of selected reactor pressure vessel steel (22 NiMoCr 3 7), above which it can be considered macroscopically homogeneous. Elastic and rate-independent plastic deformation modes are considered. The results are validated by the experimental and simulation results from the literature

  19. Analysis of elastic-plastic dynamic response of reinforced concrete frame structure

    International Nuclear Information System (INIS)

    Li Zhongcheng

    2009-01-01

    Based on a set of data from seismic response test on an R/C frame, a force-based R/C beam fibre model with non-linear material properties and bond-slip effects are presented firstly in this paper, and then the applications to the tested R/C frame are presented to illustrate the model characteristics and to show the accuracy of seismic analysis including consideration of non-linear factors. It can be concluded that the elastic-plastic analysis is a potential step toward the accurate modelling for the dynamic analyses of R/C structures. Especially for the seismic safety re-evaluation of the existing NPPs, the elastic-plastic methodology with consideration of different non-linearities should be involved. (author)

  20. Plastic damage induced fracture behaviors of dental ceramic layer structures subjected to monotonic load.

    Science.gov (United States)

    Wang, Raorao; Lu, Chenglin; Arola, Dwayne; Zhang, Dongsheng

    2013-08-01

    The aim of this study was to compare failure modes and fracture strength of ceramic structures using a combination of experimental and numerical methods. Twelve specimens with flat layer structures were fabricated from two types of ceramic systems (IPS e.max ceram/e.max press-CP and Vita VM9/Lava zirconia-VZ) and subjected to monotonic load to fracture with a tungsten carbide sphere. Digital image correlation (DIC) and fractography technology were used to analyze fracture behaviors of specimens. Numerical simulation was also applied to analyze the stress distribution in these two types of dental ceramics. Quasi-plastic damage occurred beneath the indenter in porcelain in all cases. In general, the fracture strength of VZ specimens was greater than that of CP specimens. The crack initiation loads of VZ and CP were determined as 958 ± 50 N and 724 ± 36 N, respectively. Cracks were induced by plastic damage and were subsequently driven by tensile stress at the elastic/plastic boundary and extended downward toward to the veneer/core interface from the observation of DIC at the specimen surface. Cracks penetrated into e.max press core, which led to a serious bulk fracture in CP crowns, while in VZ specimens, cracks were deflected and extended along the porcelain/zirconia core interface without penetration into the zirconia core. The rupture loads for VZ and CP ceramics were determined as 1150 ± 170 N and 857 ± 66 N, respectively. Quasi-plastic deformation (damage) is responsible for crack initiation within porcelain in both types of crowns. Due to the intrinsic mechanical properties, the fracture behaviors of these two types of ceramics are different. The zirconia core with high strength and high elastic modulus has better resistance to fracture than the e.max core. © 2013 by the American College of Prosthodontists.

  1. Length of Acupuncture Training and Structural Plastic Brain Changes in Professional Acupuncturists.

    Directory of Open Access Journals (Sweden)

    Minghao Dong

    Full Text Available The research on brain plasticity has fascinated researchers for decades. Use/training serves as an instrumental factor to influence brain neuroplasticity. Parallel to acquisition of behavioral expertise, extensive use/training is concomitant with substantial changes of cortical structure. Acupuncturists, serving as a model par excellence to study tactile-motor and emotional regulation plasticity, receive intensive training in national medical schools following standardized training protocol. Moreover, their behavioral expertise is corroborated during long-term clinical practice. Although our previous study reported functional plastic brain changes in the acupuncturists, whether or not structural plastic changes occurred in acupuncturists is yet elusive.Cohorts of acupuncturists (N = 22 and non-acupuncturists (N = 22 were recruited. Behavioral tests were delivered to assess the acupuncturists' behavioral expertise. The results confirmed acupuncturists' tactile-motor skills and emotion regulation proficiency compared to non-acupuncturists. Using the voxel-based morphometry technique, we revealed larger grey matter volumes in acupuncturists in the hand representation of the contralateral primary somatosensory cortex (SI, the right lobule V/VI and the bilateral ventral anterior cingulate cortex/ventral medial prefrontal cortex. Grey matter volumes of the SI and Lobule V/VI positively correlated with the duration of acupuncture practice.To our best knowledge, this study provides first evidence for the anatomical alterations in acupuncturists, which would possibly be the neural correlates underlying acupuncturists' exceptional skills. On one hand, we suggest our findings may have ramifications for tactile-motor rehabilitation. On the other hand, our results in emotion regulation domain may serve as a target for our future studies, from which we can understand how modulations of aversive emotions elicited by empathic pain develop in the context

  2. Elastic-plastic-creep response of structures under composite time history of loadings

    International Nuclear Information System (INIS)

    Zudans, Z.

    1975-01-01

    The purpose of this work is to derive the theory, to develop efficient numerical techniques accounting for plasticity, creep and overall equilibrium, to describe the overall structure of the resulting computer program, and to demonstrate the capability of this analysis on a real structure. Classical plasticity theory is used to develop a novel method based on the concept of 'plastic stress' for consideration of inelastic behavior. It is shown that materials stres-strain curves can be followed to any desired degree of accuracy both for isotropic and kinematic hardening. It is further shown that for kinematic hardening it is necessary to base the incremental change on the state corresponding to the mean of the initial and the final states in order to satisfy the yield condition at the final state. The equation of state and strain hardening is used to describe the creep behavior. A novel numerical technique to describe a complex load history is developed by using time as a parameter, history breakpoint determination by scanning of various load vectors and by linear interpolation between any two breakpoints in the load history. The 'plastic stress' load vector concept is utilized with iteration and extrapolation to converge to the equilibrium states with simultaneous satisfaction of the stress-strain relations for each of the iterated states. The essential features of the computer program DYPLAS-FSH, based on the theory and techniques described above, and a postprocessor program POR-FSH, based on RDT F9-5T for ratcheting and fatigue evaluation, are identified and discussed. These computer programs are used to analyse the ellipsoidal pressure vessel head of the intermediate heat exchanger of EBR-II, penetrated by two closely spaced non-radial nozzles, subjected to four consecutive composite cycles of complex mechanical and thermal loads

  3. Micro-Structural Evolution and Size-Effects in Plastically Deformed Single Crystals: Strain Gradient Continuum Modeling

    DEFF Research Database (Denmark)

    El-Naaman, Salim Abdallah

    the macroscopic effects related to strain gradients, most predict smooth micro-structures. The evolution of dislocation micro-structures, during plastic straining of ductile crystalline materials, is highly complex and nonuniform. Published experimental measurements on deformed metal crystals show distinct......An extensive amount of research has been devoted to the development of micro-mechanics based gradient plasticity continuum theories, which are necessary for modeling micron-scale plasticity when large spatial gradients of plastic strain appear. While many models have proven successful in capturing...... strain. It is clear that many challenges are associated with modeling dislocation structures, within a framework based on continuum fields, however, since the strain gradient effects are attributed to the dislocation micro-structure, it is a natural step, in the further development of gradient theories...

  4. Structural homeostasis in the nervous system: A balancing act for wiring plasticity and stability

    Directory of Open Access Journals (Sweden)

    Jun eYin

    2015-01-01

    Full Text Available Experience-dependent modifications of neural circuits provide the cellular basis for functional adaptation and learning, while presenting significant challenges to the stability of neural networks. The nervous system copes with these perturbations through a variety of compensatory mechanisms with distinct spatial and temporal profiles. Mounting evidence suggests that structural plasticity, through modifications of the number and structure of synapses, or changes in local and long-range connectivity, might contribute to the stabilization of network activity and serve as an important component of the homeostatic regulation of the nervous system. Conceptually similar to the homeostatic regulation of synaptic strength and efficacy, homeostatic structural plasticity has a profound and lasting impact on the intrinsic excitability of the neuron and circuit properties, yet remains largely unexplored. In this review, we examine recent reports describing structural modifications associated with functional compensation in both developing and adult nervous systems, and discuss the potential role for structural homeostasis in maintaining network stability and its implications in physiological and pathological conditions of the nervous systems.

  5. Spike Train Auto-Structure Impacts Post-Synaptic Firing and Timing-Based Plasticity

    Science.gov (United States)

    Scheller, Bertram; Castellano, Marta; Vicente, Raul; Pipa, Gordon

    2011-01-01

    Cortical neurons are typically driven by several thousand synapses. The precise spatiotemporal pattern formed by these inputs can modulate the response of a post-synaptic cell. In this work, we explore how the temporal structure of pre-synaptic inhibitory and excitatory inputs impact the post-synaptic firing of a conductance-based integrate and fire neuron. Both the excitatory and inhibitory input was modeled by renewal gamma processes with varying shape factors for modeling regular and temporally random Poisson activity. We demonstrate that the temporal structure of mutually independent inputs affects the post-synaptic firing, while the strength of the effect depends on the firing rates of both the excitatory and inhibitory inputs. In a second step, we explore the effect of temporal structure of mutually independent inputs on a simple version of Hebbian learning, i.e., hard bound spike-timing-dependent plasticity. We explore both the equilibrium weight distribution and the speed of the transient weight dynamics for different mutually independent gamma processes. We find that both the equilibrium distribution of the synaptic weights and the speed of synaptic changes are modulated by the temporal structure of the input. Finally, we highlight that the sensitivity of both the post-synaptic firing as well as the spike-timing-dependent plasticity on the auto-structure of the input of a neuron could be used to modulate the learning rate of synaptic modification. PMID:22203800

  6. The relationship between structured and free play in the development of a mentally handicapped child: a case study.

    Science.gov (United States)

    Hewson, S; McConkey, R; Jeffree, D

    1980-01-01

    This case study provides an individual illustration of the work of the Parental Involvement Project. A key feature of the approach used was the structured play situation. Thus, the case study also serves to demonstrate the role of structured play, and its relation to free play, in the development of a young, mentally handicapped child.

  7. ANALYSIS OF DEPENDENCE OF THE FLOW TEMPERATURE OF THE PLASTICIZED POLYMER ON THE CHEMICAL STRUCTURE AND CONCENTRATION OF THE POLYMER AND THE PLASTICIZER

    Directory of Open Access Journals (Sweden)

    Askadskiy Andrey Aleksandrovich

    2012-10-01

    Full Text Available Polymeric materials are widely used in construction. The properties of polymeric construction materials vary to a substantial extent; their durability, thermal stability, frost resistance, waterproof and dielectric properties are particularly pronounced. Their properties serve as the drivers of the high market demand for these products. These materials are applied as finishing materials, molded sanitary engineering products and effective thermal insulation and water proofing materials. The authors analyze the influence of the chemical structure and structural features of polymers on their properties. The authors consider flow and vitrification temperatures of polymers. These temperatures determine the parameters of polymeric products, including those important for the construction process. The analysis of influence of concentration of the plasticizer on the vitrification temperature is based on the two basic theories. In accordance with the first one, reduction of the vitrification temperature is proportionate to the molar fraction of the injected plasticizer. According to the second concept, reduction of the vitrification temperature is proportionate to the volume fraction of the injected solvent. Dependencies of the flow temperature on the molecular weight and the molar fraction of the plasticizer are derived for PVC. As an example, two plasticizers were considered, including dibutyl sebacate and dioctylftalatalate. The basic parameters of all mixtures were calculated through the employment of "Cascade" software programme (A.N. Nesmeyanov Institute of Organoelemental Connections, Russian Academy of Sciences.

  8. Evidence for cortical structural plasticity in humans after a day of waking and sleep deprivation.

    Science.gov (United States)

    Elvsåshagen, Torbjørn; Zak, Nathalia; Norbom, Linn B; Pedersen, Per Ø; Quraishi, Sophia H; Bjørnerud, Atle; Alnæs, Dag; Doan, Nhat Trung; Malt, Ulrik F; Groote, Inge R; Westlye, Lars T

    2017-08-01

    Sleep is an evolutionarily conserved process required for human health and functioning. Insufficient sleep causes impairments across cognitive domains, and sleep deprivation can have rapid antidepressive effects in mood disorders. However, the neurobiological effects of waking and sleep are not well understood. Recently, animal studies indicated that waking and sleep are associated with substantial cortical structural plasticity. Here, we hypothesized that structural plasticity can be observed after a day of waking and sleep deprivation in the human cerebral cortex. To test this hypothesis, 61 healthy adult males underwent structural magnetic resonance imaging (MRI) at three time points: in the morning after a regular night's sleep, the evening of the same day, and the next morning, either after total sleep deprivation (N=41) or a night of sleep (N=20). We found significantly increased right prefrontal cortical thickness from morning to evening across all participants. In addition, pairwise comparisons in the deprived group between the two morning scans showed significant thinning of mainly bilateral medial parietal cortices after 23h of sleep deprivation, including the precuneus and posterior cingulate cortex. However, there were no significant group (sleep vs. sleep deprived group) by time interactions and we can therefore not rule out that other mechanisms than sleep deprivation per se underlie the bilateral medial parietal cortical thinning observed in the deprived group. Nonetheless, these cortices are thought to subserve wakefulness, are among the brain regions with highest metabolic rate during wake, and are considered some of the most sensitive cortical regions to a variety of insults. Furthermore, greater thinning within the left medial parietal cluster was associated with increased sleepiness after sleep deprivation. Together, these findings add to a growing body of data showing rapid structural plasticity within the human cerebral cortex detectable with

  9. [Independence in Plastic Surgery - Benefit or Barrier? Analysis of the Publication Performance in Academic Plastic Surgery Depending on Varying Organisational Structures].

    Science.gov (United States)

    Schubert, C D; Leitsch, S; Haertnagl, F; Haas, E M; Giunta, R E

    2015-08-01

    Despite its recognition as an independent specialty, at German university hospitals the field of plastic surgery is still underrepresented in terms of independent departments with a dedicated research focus. The aim of this study was to analyse the publication performance within the German academic plastic surgery environment and to compare independent departments and dependent, subordinate organisational structures regarding their publication performance. Organisational structures and number of attending doctors in German university hospitals were examined via a website analysis. A pubmed analysis was applied to assess the publication performance (number of publications, cumulative impact factor, impact factor/publication, number of publications/MD, number of publications/unit) between 2009 and 2013. In a journal analysis the distribution of the cumulative impact factor and number of publications in different journals as well as the development of the impact factor in the top journals were analysed. Out of all 35 university hospitals there exist 12 independent departments for plastic surgery and 8 subordinate organisational structures. In 15 university hospitals there were no designated plastic surgery units. The number of attending doctors differed considerably between independent departments (3.6 attending doctors/unit) and subordinate organisational structures (1.1 attending doctors/unit). The majority of publications (89.0%) and of the cumulative impact factor (91.2%) as well as most of the publications/MD (54 publications/year) and publications/unit (61 publications/year) were created within the independent departments. Only in departments top publications with an impact factor > 5 were published. In general a negative trend regarding the number of publications (- 13.4%) and cumulative impact factor (- 28.9%) was observed. 58.4% of all publications were distributed over the top 10 journals. Within the latter the majority of articles were published in

  10. Structural plasticity in the dentate gyrus- revisiting a classic injury model.

    Directory of Open Access Journals (Sweden)

    Julia V. Perederiy

    2013-02-01

    Full Text Available The adult brain is in a continuous state of remodeling. This is nowhere more true than in the dentate gyrus, where competing forces such as neurodegeneration and neurogenesis dynamically modify neuronal connectivity, and can occur simultaneously. This plasticity of the adult nervous system is particularly important in the context of traumatic brain injury or deafferentation. In this review, we summarize a classic injury model, lesioning of the perforant path, which removes the main extrahippocampal input to the dentate gyrus. Early studies revealed that in response to deafferentation, axons of remaining fiber systems and dendrites of mature granule cells undergo lamina-specific changes, providing one of the first examples of structural plasticity in the adult brain. Given the increasing role of adult-generated new neurons in the function of the dentate gyrus, we also compare the response of newborn and mature granule cells following lesioning of the perforant path. These studies provide insights not only to plasticity in the dentate gyrus, but also to the response of neural circuits to brain injury.

  11. Translational control of auditory imprinting and structural plasticity by eIF2α

    Science.gov (United States)

    Batista, Gervasio; Johnson, Jennifer Leigh; Dominguez, Elena; Costa-Mattioli, Mauro; Pena, Jose L

    2016-01-01

    The formation of imprinted memories during a critical period is crucial for vital behaviors, including filial attachment. Yet, little is known about the underlying molecular mechanisms. Using a combination of behavior, pharmacology, in vivo surface sensing of translation (SUnSET) and DiOlistic labeling we found that, translational control by the eukaryotic translation initiation factor 2 alpha (eIF2α) bidirectionally regulates auditory but not visual imprinting and related changes in structural plasticity in chickens. Increasing phosphorylation of eIF2α (p-eIF2α) reduces translation rates and spine plasticity, and selectively impairs auditory imprinting. By contrast, inhibition of an eIF2α kinase or blocking the translational program controlled by p-eIF2α enhances auditory imprinting. Importantly, these manipulations are able to reopen the critical period. Thus, we have identified a translational control mechanism that selectively underlies auditory imprinting. Restoring translational control of eIF2α holds the promise to rejuvenate adult brain plasticity and restore learning and memory in a variety of cognitive disorders. DOI: http://dx.doi.org/10.7554/eLife.17197.001 PMID:28009255

  12. Structural synaptic plasticity in the hippocampus induced by spatial experience and its implications in information processing.

    Science.gov (United States)

    Carasatorre, M; Ramírez-Amaya, V; Díaz Cintra, S

    2016-10-01

    Long-lasting memory formation requires that groups of neurons processing new information develop the ability to reproduce the patterns of neural activity acquired by experience. Changes in synaptic efficiency let neurons organise to form ensembles that repeat certain activity patterns again and again. Among other changes in synaptic plasticity, structural modifications tend to be long-lasting which suggests that they underlie long-term memory. There is a large body of evidence supporting that experience promotes changes in the synaptic structure, particularly in the hippocampus. Structural changes to the hippocampus may be functionally implicated in stabilising acquired memories and encoding new information. Copyright © 2012 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Analysis of a ceramic filled bio-plastic composite sandwich structure

    International Nuclear Information System (INIS)

    Habib Ullah, M.; Islam, M. T.

    2013-01-01

    Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz

  14. Analysis of a ceramic filled bio-plastic composite sandwich structure

    Energy Technology Data Exchange (ETDEWEB)

    Habib Ullah, M. [Institute of Space Science (ANGKASA), Universiti Kebangsaan Malaysia, Bangi Selangor 43600 (Malaysia); Department of Electrical, Electronic and System Engineering, Universiti Kebangsaan Malaysia, Bangi 43600 (Malaysia); Islam, M. T. [Institute of Space Science (ANGKASA), Universiti Kebangsaan Malaysia, Bangi Selangor 43600 (Malaysia)

    2013-11-25

    Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz.

  15. Severe plastic deformation effect on structure and mechanical properties of Al-Mg-Li system alloys

    International Nuclear Information System (INIS)

    Kolobov, Yu.R.; Najdenkin, E.V.; Dudarev, E.F.; Bakach, G.P.; Pochivalov, Yu.I.; Girsova, N.V.; Ivanov, M.B.

    2002-01-01

    The study on the structural-phase states and mechanical properties of the industrial aluminium alloys Al - 5.5% Mg - 2.2% Li - 0.12% Zr, percent by weight and Al - 5% Mg - 2.2% Li -0.12% Zr - 0.2% Sc percent by weight, obtained by the impact of the intensive plastic deformation, is carried out in comparison with the initial polycrystalline state. It is established that the homogeneous ultrafine-grained structure with the second phase particles, located primarily by the grain boundaries, is formed in the studied samples by the above-mentioned treatment. Such a character of the structure leads to the shift of the temperature-velocity interval of the superplastic properties to the area of lower temperatures and higher deformation velocities [ru

  16. The interactions of normal and hyperactive children with their mothers in free play and structured tasks.

    Science.gov (United States)

    Cunningham, C E; Barkley, R A

    1979-03-01

    Groups of 20 normal and 20 hyperactive boys ranging in age from 6 to 12 years were observed interacting with their mothers in 15-min free-play and 15-min structured-task situations. Using a 15-sec interval coding procedure, 1 observer recorded the mother's response to specific antecedent behaviors of the child while a second observer recorded the child's response to specific behaviors of the mother. Hyperactive boys proved more active, less compliant, and less likely to remain on task than nonhyperactive peers. Mothers of hyperactive boys were less likely to respond positively to the child's social interactions, solitary play activities, or compliant on-task behavior. In addition, mothers of hyperactive boys imposed more structure and control on the child's play, social interactions, and task-oriented activities. It is suggested that the controlling intrusive style observed among the mothers of hyperactive boys, while initially a response to the child's overactive, impulsive, inattentive style, may further contribute to the child's behavioral difficulties.

  17. Structural and functional plasticity specific to musical training with wind instruments

    Directory of Open Access Journals (Sweden)

    Uk-Su eChoi

    2015-10-01

    Full Text Available Numerous neuroimaging studies have shown structural and functional changes resulting from musical training. Among these studies, changes in primary sensory areas are mostly related to motor functions. In this study, we looked for some similar functional and structural changes in other functional modalities, such as somatosensory function, by examining the effects of musical training with wind instruments. We found significant changes in two aspects of neuroplasticity, cortical thickness and resting-state neuronal networks. A group of subjects with several years of continuous musical training and who are currently playing in university wind ensembles showed differences in cortical thickness in lip- and tongue-related brain areas versus non-music playing subjects. Cortical thickness in lip-related brain areas was significantly thicker and that in tongue-related areas was significantly thinner in the music playing group compared with that in the non-music playing group. Association analysis of lip-related areas in the music playing group showed that the increase in cortical thickness was caused by musical training. In addition, seed-based correlation analysis showed differential activation in the precentral gyrus and supplementary motor areas between the music and non-music playing groups. These results suggest that high-intensity training with specific musical instruments could induce structural changes in related anatomical areas and could also generate a new functional neuronal network in the brain.

  18. Optimizing The Organic/Inorganic Barrier Structure For Flexible Plastic Substrate Encapsulation

    Directory of Open Access Journals (Sweden)

    Yi-Chiuan Lin

    2012-07-01

    Full Text Available A multilayered barrier structure stacked with organosilicon and silicon oxide (SiOx films consecutively prepared using plasma-enhanced chemical vapor deposition (PECVD was developed to encapsulate flexible plastic substrate. The evolution on the residual internal stress, structural quality of the organosilicon/SiOx multilayered structure as well as its adhesion to the substrate were found to correlate closely with the thickness of the inset organosilicon layer. Due to the significant discrepancy in the thermal expansion coefficient between the substrate and SiOx film, the thickness of the organosilicon layer deposited onto the substrate and SiOx film thus was crucial to optimize the barrier property of the organosilicon/SiOx structure. The organosilicon/SiOx barrier structure possessed a lowest residual compressive stress and quality adhesion to the substrate was achieved from engineering the organosilicon layer thickness in the multilayered structure. The relaxation of the residual internal stress in the barrier structure led to a dense SiOx film as a consequence of the enhancement in the Si-O-Si networks and thereby resulted in the reduction of the water vapor permeation. Accordingly, a water vapor transmission rate (WVTR below 1 × 10-2 g/m2 /day being potential for the application on the flexible optoelectronic device packaging was achievable from the 3-pairs organosilicon/SiOx multilayered structure deposited onto the polyethylene terephthalate (PET substrate.

  19. Repeated social stress leads to contrasting patterns of structural plasticity in the amygdala and hippocampus.

    Science.gov (United States)

    Patel, D; Anilkumar, S; Chattarji, S; Buwalda, B

    2018-03-23

    Previous studies have demonstrated that repeated immobilization and restraint stress cause contrasting patterns of dendritic reorganization as well as alterations in spine density in amygdalar and hippocampal neurons. Whether social and ethologically relevant stressors can induce similar patterns of morphological plasticity remains largely unexplored. Hence, we assessed the effects of repeated social defeat stress on neuronal morphology in basolateral amygdala (BLA), hippocampal CA1 and infralimbic medial prefrontal cortex (mPFC). Male Wistar rats experienced social defeat stress on 5 consecutive days during confrontation in the resident-intruder paradigm with larger and aggressive Wild-type Groningen rats. This resulted in clear social avoidance behavior one day after the last confrontation. To assess the morphological consequences of repeated social defeat, 2 weeks after the last defeat, animals were sacrificed and brains were stained using a Golgi-Cox procedure. Morphometric analyses revealed that, compared to controls, defeated Wistar rats showed apical dendritic decrease in spine density on CA1 but not BLA. Sholl analysis demonstrated a significant dendritic atrophy of CA1 basal dendrites in defeated animals. In contrast, basal dendrites of BLA pyramidal neurons exhibited enhanced dendritic arborization in defeated animals. Social stress failed to induce lasting structural changes in mPFC neurons. Our findings demonstrate for the first time that social defeat stress elicits divergent patterns of structural plasticity in the hippocampus versus amygdala, similar to what has previously been reported with repeated physical stressors. Therefore, brain region specific variations may be a universal feature of stress-induced plasticity that is shared by both physical and social stressors. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Structural plasticity of the social brain: Differential change after socio-affective and cognitive mental training.

    Science.gov (United States)

    Valk, Sofie L; Bernhardt, Boris C; Trautwein, Fynn-Mathis; Böckler, Anne; Kanske, Philipp; Guizard, Nicolas; Collins, D Louis; Singer, Tania

    2017-10-01

    Although neuroscientific research has revealed experience-dependent brain changes across the life span in sensory, motor, and cognitive domains, plasticity relating to social capacities remains largely unknown. To investigate whether the targeted mental training of different cognitive and social skills can induce specific changes in brain morphology, we collected longitudinal magnetic resonance imaging (MRI) data throughout a 9-month mental training intervention from a large sample of adults between 20 and 55 years of age. By means of various daily mental exercises and weekly instructed group sessions, training protocols specifically addressed three functional domains: (i) mindfulness-based attention and interoception, (ii) socio-affective skills (compassion, dealing with difficult emotions, and prosocial motivation), and (iii) socio-cognitive skills (cognitive perspective-taking on self and others and metacognition). MRI-based cortical thickness analyses, contrasting the different training modules against each other, indicated spatially diverging changes in cortical morphology. Training of present-moment focused attention mostly led to increases in cortical thickness in prefrontal regions, socio-affective training induced plasticity in frontoinsular regions, and socio-cognitive training included change in inferior frontal and lateral temporal cortices. Module-specific structural brain changes correlated with training-induced behavioral improvements in the same individuals in domain-specific measures of attention, compassion, and cognitive perspective-taking, respectively, and overlapped with task-relevant functional networks. Our longitudinal findings indicate structural plasticity in well-known socio-affective and socio-cognitive brain networks in healthy adults based on targeted short daily mental practices. These findings could promote the development of evidence-based mental training interventions in clinical, educational, and corporate settings aimed at

  1. Hippocampal structural plasticity accompanies the resulting contextual fear memory following stress and fear conditioning.

    Science.gov (United States)

    Giachero, Marcelo; Calfa, Gaston D; Molina, Victor A

    2013-10-15

    The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to stress prevented both the enhancement of fear retention and an increase in the density of total and mature dendritic spines in DH. These findings emphasize the role of the stress-induced attenuation of GABAergic neurotransmission in BLA in the promoting influence of stress on fear memory and on synaptic remodeling in DH. In conclusion, the structural remodeling in DH accompanied the facilitated fear memory following a combination of fear conditioning and stressful stimulation.

  2. Structural plasticity in mesencephalic dopaminergic neurons produced by drugs of abuse: critical role of BDNF and dopamine.

    Directory of Open Access Journals (Sweden)

    Ginetta eCollo

    2014-11-01

    Full Text Available Mesencephalic dopaminergic neurons were suggested to be a critical physiopathology substrate for addiction disorders. Among neuroadaptive processes to addictive drugs, structural plasticity has attracted attention. While structural plasticity occurs at both pre- and post-synaptic levels in the mesolimbic dopaminergic system, the present review focuses only on dopaminergic neurons. Exposures to addictive drugs determine two opposite structural responses, hypothrophic plasticity produced by opioids and cannabinoids (in particular during the early withdrawal phase and hypertrophic plasticity, mostly driven by psychostimulants and nicotine. In vitro and in vivo studies indentified BDNF and extracellular dopamine as two critical factors in determining structural plasticity, the two molecules sharing similar intracellular pathways involved in cell soma and dendrite growth, the MEK-ERK1/2 and the PI3K-Akt-mTOR, via preferential activation of TrkB and dopamine D3 receptors, respectively. At present information regarding specific structural changes associated to the various stages of the addiction cycle is incomplete. Encouraging neuroimaging data in humans indirectly support the preclinical evidence of hypotrophic and hypertrophic effects, suggesting a possible differential engagement of dopamine neurons in parallel and partially converging circuits controlling motivation, stress and emotions.

  3. The role of structural characteristics in video-game play motivation: a Q-methodology study.

    Science.gov (United States)

    Westwood, Dave; Griffiths, Mark D

    2010-10-01

    Until recently, there has been very little naturalistic study of what gaming experiences are like, and how gaming fits into people's lives. Using a recently developed structural characteristic taxonomy of video games, this study examined the psycho-structural elements of computer games that motivate gamers to play them. Using Q-Sort methodology, 40 gamers participated in an online Q-sort task. Results identified six distinct types of gamers based on the factors generated: (a) story-driven solo gamers; (b) social gamers; (c) solo limited gamers; (d) hardcore online gamers; (e) solo control/identity gamers; and (f ) casual gamers. These gaming types are discussed, and a brief evaluation of similar and unique elements of the different types of gamer is also offered. The current study shows Q-methodology to be a relevant and applicable method in the psychological research of gaming.

  4. Structured Play Therapy Groups for Preschoolers: facilitating the emergence of social competence.

    Science.gov (United States)

    Stone, Susan; Stark, Martha

    2013-01-01

    Over the years, we have developed a working model of Structured Play Therapy Groups for Preschoolers, an innovative treatment approach designed to address the needs of young children ages 3 to 5 struggling to adjust to the social demands of their preschool classrooms. These short-term therapy groups facilitate development of the young child's social competence and capacity to participate effectively in a classroom environment. Although the literature on therapy groups for children suggests that preschoolers are not yet evolved enough developmentally to engage actively in a group process, our experience indicates otherwise. The model of treatment presented here will therefore challenge that contention with the claim that not only can preschoolers participate in a structured therapy group of peers but they can, by virtue of that very participation, benefit in ways that will prepare them (as they transition from preschool to kindergarten) for the ever-increasing demands of their ever-expanding social milieus.

  5. Activity-Dependent Exocytosis of Lysosomes Regulates the Structural Plasticity of Dendritic Spines.

    Science.gov (United States)

    Padamsey, Zahid; McGuinness, Lindsay; Bardo, Scott J; Reinhart, Marcia; Tong, Rudi; Hedegaard, Anne; Hart, Michael L; Emptage, Nigel J

    2017-01-04

    Lysosomes have traditionally been viewed as degradative organelles, although a growing body of evidence suggests that they can function as Ca 2+ stores. Here we examined the function of these stores in hippocampal pyramidal neurons. We found that back-propagating action potentials (bpAPs) could elicit Ca 2+ release from lysosomes in the dendrites. This Ca 2+ release triggered the fusion of lysosomes with the plasma membrane, resulting in the release of Cathepsin B. Cathepsin B increased the activity of matrix metalloproteinase 9 (MMP-9), an enzyme involved in extracellular matrix (ECM) remodelling and synaptic plasticity. Inhibition of either lysosomal Ca 2+ signaling or Cathepsin B release prevented the maintenance of dendritic spine growth induced by Hebbian activity. This impairment could be rescued by exogenous application of active MMP-9. Our findings suggest that activity-dependent exocytosis of Cathepsin B from lysosomes regulates the long-term structural plasticity of dendritic spines by triggering MMP-9 activation and ECM remodelling. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  6. Influence of Plastic Deformation on Martensitic Transformation During Hot Stamping of Complex Structure Auto Parts

    Science.gov (United States)

    Shen, Yuhan; Song, Yanli; Hua, Lin; Lu, Jue

    2017-04-01

    The ultra-high strength steel auto parts manufactured by hot stamping are widely applied for weight reduction and safety improvement. During the hot stamping process, hot forming and quenching are performed in one step wherein plastic deformation and phase transformation simultaneously take place and affect each other. Thereinto, the influence of deformation on martensitic transformation is of great importance. In the present paper, the influence of plastic deformation on martensitic transformation during hot stamping of complex structure auto parts was investigated. For this purpose, a B-pillar reinforced panel in B1500HS steel was manufactured by hot stamping, and the process was simulated by finite element software based on a thermo-mechanical-metallurgical coupled model. Considering various deformation degrees, the microstructures and mechanical properties at four typical locations of the hot stamped B-pillar reinforced panel were detected. The results show that the martensitic content and the microhardness increase with the increase in the deformation amount. There are two reasons causing this phenomenon: (1) the increase in mechanical driving force and (2) the increased probability of the martensitic nucleation at crystal defects. The x-ray diffraction analysis indicates the carbon enrichment in retained austenite which results from the carbon diffusion during the low-carbon martensite formation. Furthermore, the carbon content decreases with the increase in the deformation amount, because the deformation of austenite suppresses the carbon diffusion.

  7. Functional and Structural Brain Plasticity Enhanced by Motor and Cognitive Rehabilitation in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Luca Prosperini

    2015-01-01

    Full Text Available Rehabilitation is recognized to be important in ameliorating motor and cognitive functions, reducing disease burden, and improving quality of life in patients with multiple sclerosis (MS. In this systematic review, we summarize the existing evidences that motor and cognitive rehabilitation may enhance functional and structural brain plasticity in patients with MS, as assessed by means of the most advanced neuroimaging techniques, including diffusion tensor imaging and task-related and resting-state functional magnetic resonance imaging (MRI. In most cases, the rehabilitation program was based on computer-assisted/video game exercises performed in either an outpatient or home setting. Despite their heterogeneity, all the included studies describe changes in white matter microarchitecture, in task-related activation, and/or in functional connectivity following both task-oriented and selective training. When explored, relevant correlation between improved function and MRI-detected brain changes was often found, supporting the hypothesis that training-induced brain plasticity is specifically linked to the trained domain. Small sample sizes, lack of randomization and/or an active control group, as well as missed relationship between MRI-detected changes and clinical performance, are the major drawbacks of the selected studies. Knowledge gaps in this field of research are also discussed to provide a framework for future investigations.

  8. The influence of maltodextrins on the structure and properties of compression-molded starch plastic sheets

    NARCIS (Netherlands)

    Soest, van J.J.G.; Kortleve, P.M.

    1999-01-01

    Starch plastic sheets were prepared by compression molding of starch-based plastic granulates. The granulates were prepared by extrusion processing of mixtures of granular potato starch and several maltodextrins (5% w/w) in the presence of glycerol and water as plasticizers and lecithin as melt flow

  9. Aging and demographic plasticity in response to experimental age structures in honeybees (Apis mellifera L).

    Science.gov (United States)

    Rueppell, Olav; Linford, Robyn; Gardner, Preston; Coleman, Jennifer; Fine, Kari

    2008-08-01

    Honeybee colonies are highly integrated functional units characterized by a pronounced division of labor. Division of labor among workers is mainly age-based, with younger individuals focusing on in-hive tasks and older workers performing the more hazardous foraging activities. Thus, experimental disruption of the age composition of the worker hive population is expected to have profound consequences for colony function. Adaptive demography theory predicts that the natural hive age composition represents a colony-level adaptation and thus results in optimal hive performance. Alternatively, the hive age composition may be an epiphenomenon, resulting from individual life history optimization. We addressed these predictions by comparing individual worker longevity and brood production in hives that were composed of a single age cohort, two distinct age cohorts, and hives that had a continuous, natural age distribution. Four experimental replicates showed that colonies with a natural age composition did not consistently have a higher life expectancy and/or brood production than the single cohort or double cohort hives. Instead, a complex interplay of age structure, environmental conditions, colony size, brood production, and individual mortality emerged. A general trade-off between worker life expectancy and colony productivity was apparent, and the transition from in-hive tasks to foraging was the most significant predictor of worker lifespan irrespective of the colony age structure. We conclude that the natural age structure of honeybee hives is not a colony-level adaptation. Furthermore, our results show that honeybees exhibit pronounced demographic plasticity in addition to behavioral plasticity to react to demographic disturbances of their societies.

  10. Auxetic hexachiral structures with wavy ligaments for large elasto-plastic deformation

    Science.gov (United States)

    Zhu, Yilin; Wang, Zhen-Pei; Hien Poh, Leong

    2018-05-01

    The hexachiral structure is in-plane isotropic in small deformation. When subjected to large elasto-plastic deformation, however, the hexachiral structure tends to lose its auxeticity and/or isotropy—properties which are desirable in many potential applications. The objective of this study is to improve these two mechanical properties, without significantly compromising the effective yield stress, in the regime with significant material and geometrical nonlinearity effects. It is found that the deformation mechanisms underlying the auxeticity and isotropy properties of a hexachiral structure are largely influenced by the extent of rotation of the central ring in a unit cell. To facilitate the development of this deformation mechanism, an improved design with wavy ligaments is proposed. The improved performance of the proposed hexachiral structure is demonstrated. An initial study on possible applications as a protective material is next carried out, where the improved hexachiral design is shown to exhibit higher specific energy absorption capacity compared to the original design, as well as standard honeycomb structures.

  11. Vacuolar processing enzyme plays an essential role in the crystalline structure of glutelin in rice seed.

    Science.gov (United States)

    Kumamaru, Toshihiro; Uemura, Yuji; Inoue, Yoshimi; Takemoto, Yoko; Siddiqui, Sadar Uddin; Ogawa, Masahiro; Hara-Nishimura, Ikuko; Satoh, Hikaru

    2010-01-01

    To identify the function of genes that regulate the processing of proglutelin, we performed an analysis of glup3 mutants, which accumulates excess amounts of proglutelin and lack the vacuolar processing enzyme (VPE). VPE activity in developing seeds from glup3 lines was reduced remarkably compared with the wild type. DNA sequencing of the VPE gene in glup3 mutants revealed either amino acid substitutions or the appearance of a stop codon within the coding region. Microscopic observations showed that alpha-globulin and proglutelin were distributed homogeneously within glup3 protein storage vacuoles (PSVs), and that glup3 PSVs lacked the crystalline lattice structure typical of wild-type PSVs. This suggests that the processing of proglutelin by VPE in rice is essential for proper PSV structure and compartmentalization of storage proteins. Growth retardation in glup3 seedlings was also observed, indicating that the processing of proglutelin influences early seedling development. These findings indicate that storage of glutelin in its mature form as a crystalline structure in PSVs is required for the rapid use of glutelin as a source of amino acids during early seedling development. In conclusion, VPE plays an important role in the formation of protein crystalline structures in PSVs.

  12. A developmentally plastic adult mouse kidney cell line spontaneously generates multiple adult kidney structures

    International Nuclear Information System (INIS)

    Webb, Carol F.; Ratliff, Michelle L.; Powell, Rebecca; Wirsig-Wiechmann, Celeste R.; Lakiza, Olga; Obara, Tomoko

    2015-01-01

    Despite exciting new possibilities for regenerative therapy posed by the ability to induce pluripotent stem cells, recapitulation of three-dimensional kidneys for repair or replacement has not been possible. ARID3a-deficient mouse tissues generated multipotent, developmentally plastic cells. Therefore, we assessed the adult mouse ARID3a−/− kidney cell line, KKPS5, which expresses renal progenitor surface markers as an alternative cell source for modeling kidney development. Remarkably, these cells spontaneously developed into multicellular nephron-like structures in vitro, and engrafted into immunocompromised medaka mesonephros, where they formed mouse nephron structures. These data implicate KKPS5 cells as a new model system for studying kidney development. - Highlights: • An ARID3a-deficient mouse kidney cell line expresses multiple progenitor markers. • This cell line spontaneously forms multiple nephron-like structures in vitro. • This cell line formed mouse kidney structures in immunocompromised medaka fish kidneys. • Our data identify a novel model system for studying kidney development

  13. A developmentally plastic adult mouse kidney cell line spontaneously generates multiple adult kidney structures

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Carol F., E-mail: carol-webb@omrf.org [Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Immunobiology and Cancer Research, Oklahoma Medical Research Foundation, Oklahoma City, OK (United States); Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Ratliff, Michelle L., E-mail: michelle-ratliff@omrf.org [Immunobiology and Cancer Research, Oklahoma Medical Research Foundation, Oklahoma City, OK (United States); Powell, Rebecca, E-mail: rebeccapowell@gmail.com [Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Wirsig-Wiechmann, Celeste R., E-mail: celeste-wirsig@ouhsc.edu [Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Lakiza, Olga, E-mail: olga-lakiza@ouhsc.edu [Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Obara, Tomoko, E-mail: tomoko-obara@ouhsc.edu [Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2015-08-07

    Despite exciting new possibilities for regenerative therapy posed by the ability to induce pluripotent stem cells, recapitulation of three-dimensional kidneys for repair or replacement has not been possible. ARID3a-deficient mouse tissues generated multipotent, developmentally plastic cells. Therefore, we assessed the adult mouse ARID3a−/− kidney cell line, KKPS5, which expresses renal progenitor surface markers as an alternative cell source for modeling kidney development. Remarkably, these cells spontaneously developed into multicellular nephron-like structures in vitro, and engrafted into immunocompromised medaka mesonephros, where they formed mouse nephron structures. These data implicate KKPS5 cells as a new model system for studying kidney development. - Highlights: • An ARID3a-deficient mouse kidney cell line expresses multiple progenitor markers. • This cell line spontaneously forms multiple nephron-like structures in vitro. • This cell line formed mouse kidney structures in immunocompromised medaka fish kidneys. • Our data identify a novel model system for studying kidney development.

  14. Modeling and Analysis of Size-Dependent Structural Problems by Using Low- Order Finite Elements with Strain Gradient Plasticity

    International Nuclear Information System (INIS)

    Park, Moon Shik; Suh, Yeong Sung; Song, Seung

    2011-01-01

    An elasto-plastic finite element method using the theory of strain gradient plasticity is proposed to evaluate the size dependency of structural plasticity that occurs when the configuration size decreases to micron scale. For this method, we suggest a low-order plane and three-dimensional displacement-based elements, eliminating the need for a high order, many degrees of freedom, a mixed element, or super elements, which have been considered necessary in previous researches. The proposed method can be performed in the framework of nonlinear incremental analysis in which plastic strains are calculated and averaged at nodes. These strains are then interpolated and differentiated for gradient calculation. We adopted a strain-gradient-hardening constitutive equation from the Taylor dislocation model, which requires the plastic strain gradient. The developed finite elements are tested numerically on the basis of typical size-effect problems such as micro-bending, micro-torsion, and micro-voids. With respect to the strain gradient plasticity, i.e., the size effects, the results obtained by using the proposed method, which are simple in their calculation, are in good agreement with the experimental results cited in previously published papers

  15. Physical exercise in overweight to obese individuals induces metabolic- and neurotrophic-related structural brain plasticity

    Directory of Open Access Journals (Sweden)

    Karsten eMueller

    2015-07-01

    Full Text Available Previous cross-sectional studies on body-weight-related alterations in brain structure revealed profound changes in the gray matter (GM and white matter (WM that resemble findings obtained from individuals with advancing age. This suggests that obesity may lead to structural brain changes that are comparable with brain aging. Here, we asked whether weight-loss-dependent improved metabolic and neurotrophic functioning parallels the reversal of obesity-related alterations in brain structure. To this end we applied magnetic resonance imaging together with voxel-based morphometry and diffusion-tensor imaging in overweight to obese individuals who participated in a fitness course with intensive physical training three days per week over a period of three months. After the fitness course, participants presented, with inter-individual heterogeneity, a reduced body mass index (BMI, reduced serum leptin concentrations, elevated high-density lipoprotein-cholesterol (HDL-C, and alterations of serum brain-derived neurotrophic factor (BDNF concentrations suggesting changes of metabolic and neurotrophic function. Exercise-dependent changes in BMI and serum concentration of BDNF, leptin, and HDL-C were related to an increase in GM density in the left hippocampus, the insular cortex, and the left cerebellar lobule. We also observed exercise-dependent changes of diffusivity parameters in surrounding WM structures as well as in the corpus callosum. These findings suggest that weight-loss due to physical exercise in overweight to obese participants induces profound structural brain plasticity, not primarily of sensorimotor brain regions involved in physical exercise, but of regions previously reported to be structurally affected by an increased body weight and functionally implemented in gustation and cognitive processing.

  16. Influence of Severe Plastic Deformation on Mechanical Properties and Structure of Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    Ondřej Hilšer

    2016-09-01

    Full Text Available Article is devoted to analysis of ECAP (Equal Channel Angular Pressing method, which uses a high degree of deformation to achieve a very fine-grained structure of formed material. Utilization of The ECAP technology enables attainment of required properties of selected materials by using of severe plastic deformation (SPD methods. In the experimental part the influence of the number of passes through forming tool with classical geometry (angle of 90° between channels was studied to achieve maximum hardening (expressed by deformation resistance and achieved value of hardness HV10. Also the metallographic analysis (detection of achieved grain refinement was carried out. From comparison of results achieved at both alloys it can be stated that for given forming by ECAP method the EN AW-8006 alloy is preferable, because higher strength degree was obtained by achieving of very fine grained structure. When using the same method of forming by ECAP method the EN AW-2024 alloy has lower hardening and structure refinement.

  17. The influences of soil and nearby structures on dispersion characteristics of wave propagating along buried plastic pipes

    Science.gov (United States)

    Liu, Shuyong; Jiang, J.; Parr, Nicola

    2016-09-01

    Water loss in distribution systems is a global problem for the water industry and governments. According to the international water supply association (IWSA), as a result of leaks from distribution pipes, 20% to 30% of water is lost while in transit from treatment plants to consumers. Although governments have tried to push the water industry to reduce the water leaks, a lot of experts have pointed out that a wide use of plastic pipes instead of metal pipes in recent years has caused difficulties in the detection of leaks using current acoustic technology. Leaks from plastic pipes are much quieter than traditional metal pipes and comparing to metal pipes the plastic pipes have very different coupling characteristics with soil, water and surrounding structures, such as other pipes, road surface and building foundations. The dispersion characteristics of wave propagating along buried plastic pipes are investigated in this paper using finite element and boundary element based models. Both empty and water- filled pipes were considered. Influences from nearby pipes and building foundations were carefully studied. The results showed that soil condition and nearby structures have significant influences on the dispersion characteristics of wave propagating along buried plastic pipes.

  18. Evolution of the structure and the phase composition of a bainitic structural steel during plastic deformation

    Science.gov (United States)

    Nikitina, E. N.; Glezer, A. M.; Ivanov, Yu. F.; Aksenova, K. V.; Gromov, V. E.; Kazimirov, S. A.

    2017-10-01

    The evolution of the phase composition and the imperfect substructure of the 30Kh2N2MFA bainitic structural steel subjected to compressive deformation by 36% is quantitatively analyzed. It is shown that deformation is accompanied by an increase in the scalar dislocation density, a decrease in the longitudinal fragment sizes, an increase in the number of stress concentrators, the dissolution of cementite particles, and the transformation of retained austenite.

  19. On play and playing.

    Science.gov (United States)

    Rudan, Dusko

    2013-12-01

    The paper offers a review of the development of the concept of play and playing. The true beginnings of the development of the theories of play are set as late as in the 19th century. It is difficult to define play as such; it may much more easily be defined through its antipode--work. In the beginning, play used to be connected with education; it was not before Freud's theory of psychoanalysis and Piaget's developmental psychology that the importance of play in a child's development began to be explained in more detail. The paper further tackles the role of play in the adult age. Detailed attention is paid to psychodynamic and psychoanalytic authors, in particular D. W. Winnicott and his understanding of playing in the intermediary (transitional) empirical or experiential space. In other words, playing occupies a space and time of its own. The neuroscientific concept of playing is also tackled, in the connection with development as well.

  20. Learning Discloses Abnormal Structural and Functional Plasticity at Hippocampal Synapses in the APP23 Mouse Model of Alzheimer's Disease

    Science.gov (United States)

    Middei, Silvia; Roberto, Anna; Berretta, Nicola; Panico, Maria Beatrice; Lista, Simone; Bernardi, Giorgio; Mercuri, Nicola B.; Ammassari-Teule, Martine; Nistico, Robert

    2010-01-01

    B6-Tg/Thy1APP23Sdz (APP23) mutant mice exhibit neurohistological hallmarks of Alzheimer's disease but show intact basal hippocampal neurotransmission and synaptic plasticity. Here, we examine whether spatial learning differently modifies the structural and electrophysiological properties of hippocampal synapses in APP23 and wild-type mice. While…

  1. Polymerization and Structure of Bio-Based Plastics: A Computer Simulation

    Science.gov (United States)

    Khot, Shrikant N.; Wool, Richard P.

    2001-03-01

    We recently examined several hundred chemical pathways to convert chemically functionalized plant oil triglycerides, monoglycerides and reactive diluents into high performance plastics with a broad range of properties (US Patent No. 6,121,398). The resulting polymers had linear, branched, light- and highly-crosslinked chain architectures and could be used as pressure sensitive adhesives, elastomers and high performance rigid thermoset composite resins. To optimize the molecular design and minimize the number of chemical trials in this system with excess degrees of freedom, we developed a computer simulation of the free radical polymerization process. The triglyceride structure, degree of chemical substitution, mole fractions, fatty acid distribution function, and reaction kinetic parameters were used as initial inputs on a 3d lattice simulation. The evolution of the network fractal structure was computed and used to measure crosslink density, dangling ends, degree of reaction and defects in the lattice. The molecular connectivity was used to determine strength via a vector percolation model of fracture. The simulation permitted the optimal design of new bio-based materials with respect to monomer selection, cure reaction conditions and desired properties. Supported by the National Science Foundation

  2. Study of Ag/RGO/ITO sandwich structure for resistive switching behavior deposited on plastic substrate

    Science.gov (United States)

    Vartak, Rajdeep; Rag, Adarsh; De, Shounak; Bhat, Somashekhara

    2018-05-01

    We report here the use of facile and environmentally benign way synthesized reduced graphene oxide (RGO) for low-voltage non-volatile memory device as charge storing element. The RGO solutions have been synthesized using electrochemical exfoliation of battery electrode. The solution processed based RGO solution is suitable for large area and low-cost processing on plastic substrate. Room-temperature current-voltage characterisation has been carried out in Ag/RGO/ITO PET sandwich configuration to study the type of trap distribution. It is observed that in the low-voltage sweep, ohmic current is the main mechanism of current flow and trap filled/assisted conduction is observed at high-sweep voltage region. The Ag/RGO/ITO PET sandwich structure showed bipolar resistive switching behavior. These mechanisms can be analyzed based on oxygen availability and vacancies in the RGO giving rise to continuous least resistive path (conductive) and high resistance path along the structure. An Ag/RGO/ITO arrangement demonstrates long retention time with low operating voltage, low set/reset voltage, good ON/OFF ratio of 103 (switching transition between lower resistance state and higher resistance state and decent switching performance. The RGO memory showed decent results with an almost negligible degradation in switching properties which can be used for low-voltage and low-cost advanced flexible electronics.

  3. Structural Plasticity of Malaria Dihydroorotate Dehydrogenase Allows Selective Binding of Diverse Chemical Scaffolds

    International Nuclear Information System (INIS)

    Deng, Xiaoyi; Gujjar, Ramesh; El Mazouni, Farah; Kaminsky, Werner; Malmquist, Nicholas A.; Goldsmith, Elizabeth J.; Rathod, Pradipsinh K.; Phillips, Margaret A.

    2009-01-01

    Malaria remains a major global health burden and current drug therapies are compromised by resistance. Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) was validated as a new drug target through the identification of potent and selective triazolopyrimidine-based DHODH inhibitors with anti-malarial activity in vivo. Here we report x-ray structure determination of PfDHODH bound to three inhibitors from this series, representing the first of the enzyme bound to malaria specific inhibitors. We demonstrate that conformational flexibility results in an unexpected binding mode identifying a new hydrophobic pocket on the enzyme. Importantly this plasticity allows PfDHODH to bind inhibitors from different chemical classes and to accommodate inhibitor modifications during lead optimization, increasing the value of PfDHODH as a drug target. A second discovery, based on small molecule crystallography, is that the triazolopyrimidines populate a resonance form that promotes charge separation. These intrinsic dipoles allow formation of energetically favorable H-bond interactions with the enzyme. The importance of delocalization to binding affinity was supported by site-directed mutagenesis and the demonstration that triazolopyrimidine analogs that lack this intrinsic dipole are inactive. Finally, the PfDHODH-triazolopyrimidine bound structures provide considerable new insight into species-selective inhibitor binding in this enzyme family. Together, these studies will directly impact efforts to exploit PfDHODH for the development of anti-malarial chemotherapy.

  4. Continuous liquid level detection based on two parallel plastic optical fibers in a helical structure

    Science.gov (United States)

    Zhang, Yingzi; Hou, Yulong; Zhang, Yanjun; Hu, Yanjun; Zhang, Liang; Gao, Xiaolong; Zhang, Huixin; Liu, Wenyi

    2018-02-01

    A simple and low-cost continuous liquid-level sensor based on two parallel plastic optical fibers (POFs) in a helical structure is presented. The change in the liquid level is determined by measuring the side-coupling power in the passive fiber. The side-coupling ratio is increased by just filling the gap between the two POFs with ultraviolet-curable optical cement, making the proposed sensor competitive. The experimental results show that the side-coupling power declines as the liquid level rises. The sensitivity and the measurement range are flexible and affected by the geometric parameters of the helical structure. A higher sensitivity of 0.0208 μW/mm is acquired for a smaller curvature radius of 5 mm, and the measurement range can be expanded to 120 mm by enlarging the screw pitch to 40 mm. In addition, the reversibility and temperature dependence are studied. The proposed sensor is a cost-effective solution offering the advantages of a simple fabrication process, good reversibility, and compensable temperature dependence.

  5. ECT: its brain enabling effects. A review of electroconvulsive therapy-induced structural brain plasticity

    NARCIS (Netherlands)

    Bouckaert, F.; Sienaert, P.; Obbels, J.; Dols, A.; Vandenbulcke, M.; Stek, M.L.; Bolwig, T.

    2014-01-01

    BACKGROUND: Since the past 2 decades, new evidence for brain plasticity has caused a shift in both preclinical and clinical ECT research from falsifying the "brain damage hypothesis" toward exploring ECT's enabling brain (neuro)plasticity effects. METHODS: By reviewing the available animal and human

  6. Structural test and analysis of a model of a BWR suppression chamber support in the plastic regime

    International Nuclear Information System (INIS)

    Blumer, U.R.; Klaeui, E.; Bosshard, E.P.

    1991-01-01

    A BWR Mark I suppression pool support has been analysed and tested in the laboratory. The aim was the demonstration of the acceptability of hypothetical dynamic loadings resulting from simultaneous steam blowdown through all safety relief valves. The analysis has shown that plastic deformation will locally occur, which is difficult to assess purely theoretical. Therefore tests in reduced scale were performed that show the amount and distribution of plastic flow in the supports. The paper describes the elastic analysis, the theory of the scaling laws for the reduced scale test, the test and its results. It also shows the thermographical method that has been used to determine the plastic material flow in the support structure. (author)

  7. Plasticity Detection and Quantification in Monopile Support Structures Due to Axial Impact Loading

    Directory of Open Access Journals (Sweden)

    Meijers P.C.

    2018-01-01

    Full Text Available Recent developments in the construction of offshore wind turbines have created the need for a method to detect whether a monopile foundation is plastically deformed during the installation procedure. Since measurements at the pile head are difficult to perform, a method based on measurements at a certain distance below the pile head is proposed in this work for quantification of the amount of plasticity. By considering a onedimensional rod model with an elastic-perfectly plastic constitutive relation, it is shown that the occurrence of plastic deformation caused by an impact load can be detected from these measurements. Furthermore, this plastic deformation can be quantified by the same measurement with the help of an energy balance. The effectiveness of the proposed method is demonstrated via a numerical example.

  8. Spatial and seasonal variation in diversity and structure of microbial biofilms on marine plastics in Northern European waters.

    Science.gov (United States)

    Oberbeckmann, Sonja; Loeder, Martin G J; Gerdts, Gunnar; Osborn, A Mark

    2014-11-01

    Plastic pollution is now recognised as a major threat to marine environments and marine biota. Recent research highlights that diverse microbial species are found to colonise plastic surfaces (the plastisphere) within marine waters. Here, we investigate how the structure and diversity of marine plastisphere microbial community vary with respect to season, location and plastic substrate type. We performed a 6-week exposure experiment with polyethylene terephthalate (PET) bottles in the North Sea (UK) as well as sea surface sampling of plastic polymers in Northern European waters. Scanning electron microscopy revealed diverse plastisphere communities comprising prokaryotic and eukaryotic microorganisms. Denaturing gradient gel electrophoresis (DGGE) and sequencing analysis revealed that plastisphere microbial communities on PET fragments varied both with season and location and comprised of bacteria belonging to Bacteroidetes, Proteobacteria, Cyanobacteria and members of the eukaryotes Bacillariophyceae and Phaeophyceae. Polymers sampled from the sea surface mainly comprised polyethylene, polystyrene and polypropylene particles. Variation within plastisphere communities on different polymer types was observed, but communities were primarily dominated by Cyanobacteria. This research reveals that the composition of plastisphere microbial communities in marine waters varies with season, geographical location and plastic substrate type. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  9. The development of the design method of nuclear piping system supported by elasto-plastic support structures (Part 1)

    International Nuclear Information System (INIS)

    Endo, R.; Murota, M.; Kawahata, J.-I.; Sato, T.; Mekomoto, Y.; Takayama, Y.; Kobayashi, H.; Hirose, J.

    1993-01-01

    The conventional aseismic design method of nuclear piping system is very conservative because of the accumulation of various safety factors in the design process, and nuclear piping systems are thought to have a large safety margin. Considering this situation, we promoted research to further rationalize nuclear power plants by reducing the amount of support structures and reducing the piping seismic response through vibration energy absorption resulting from the elasto-plastic behavior of piping support structures. The research has the following three stages. In the first stage, we select conventional piping support structures in Japanese light-water reactors that exhibit elasto-plastic behavior, and study the displacement dependency and the vibration frequency dependency on the stiffness and the energy absorption by testing their model. In the second stage, we make a piping test model with support structures whose characteristics have already been obtained, and perform vibration tests on a shaking table. In this way, we analyze the piping vibration characteristics by sinusoidal wave sweep tests and the piping response characteristics by seismic wave vibration tests, when the support structures are in an elasto-plastic condition. In the third stage, a general method is developed to evaluate the characteristics of the support structures obtained in the tests and it is applied to the evaluation of the characteristics of general support structures. A simplified analysis method is developed to evaluate the piping seismic response using the piping model test result. To expand the results mentioned above, we are developing a seismic design method of piping systems that allows support structures to have elasto-plastic behaviour. This paper reports the results of experiments conducted under the joint research program of Japanese electric power companies with support elements in the first stage and those with piping models in the second stage

  10. βCaMKII plays a nonenzymatic role in hippocampal synaptic plasticity and learning by targeting αCaMKII to synapses.

    Science.gov (United States)

    Borgesius, Nils Z; van Woerden, Geeske M; Buitendijk, Gabrielle H S; Keijzer, Nanda; Jaarsma, Dick; Hoogenraad, Casper C; Elgersma, Ype

    2011-07-13

    The calcium/calmodulin-dependent kinase type II (CaMKII) holoenzyme of the forebrain predominantly consists of heteromeric complexes of the αCaMKII and βCaMKII isoforms. Yet, in contrast to αCaMKII, the role of βCaMKII in hippocampal synaptic plasticity and learning has not been investigated. Here, we compare two targeted Camk2b mouse mutants to study the role of βCaMKII in hippocampal function. Using a Camk2b(-/-) mutant, in which βCaMKII is absent, we show that both hippocampal-dependent learning and Schaffer collateral-CA1 long-term potentiation (LTP) are highly dependent upon the presence of βCaMKII. We further show that βCaMKII is required for proper targeting of αCaMKII to the synapse, indicating that βCaMKII regulates the distribution of αCaMKII between the synaptic pool and the adjacent dendritic shaft. In contrast, localization of αCaMKII, hippocampal synaptic plasticity and learning were unaffected in the Camk2b(A303R) mutant, in which the calcium/calmodulin-dependent activation of βCaMKII is prevented, while the F-actin binding and bundling property is preserved. This indicates that the calcium/calmodulin-dependent kinase activity of βCaMKII is fully dispensable for hippocampal learning, LTP, and targeting of αCaMKII, but implies a critical role for the F-actin binding and bundling properties of βCaMKII in synaptic function. Together, our data provide compelling support for a model of CaMKII function in which αCaMKII and βCaMKII act in concert, but with distinct functions, to regulate hippocampal synaptic plasticity and learning.

  11. The development of design method of nuclear piping system supported by elasto-plastic support structures (part 2)

    International Nuclear Information System (INIS)

    Endo, R.; Murota, M.; Kawabata, J-I.; Hirose, J.; Nekomoto, Y.; Takayama, Y.; Kobayashi, H.

    1995-01-01

    The conventional seismic design method of nuclear piping system is very conservative because of the accumulation of various safety factors in the design process, and nuclear piping systems are thought to have a large safety margin. Considering this situations, research program was promoted to furthermore rationalize nuclear power plants by reducing the amount of support structures and reducing the piping's seismic response through vibration energy absorption resulting from the elasto-plastic behavior of piping support structures. The research had the following three stages. In the first stage, we selected conventional piping support structures in light-water reactors that exhibited elasto-plastic behavior, and studied the effect of displacement and the vibration frequency on the stiffness and on the energy absorption by testing these models. In the second stage, vibration tests were performed using piping models with support structures on shaking tables. The piping vibration characteristics were clarified by sinusoidal sweep tests and the piping response characteristics by seismic wave vibration tests when the support structures were in an elasto-plastic condition. In the third stage, a general method was developed to evaluate the characteristics of a variety of support structures in the tests. A simplified analysis method was also developed to evaluate the piping seismic response using the piping model test result. To expand the results mentioned above, we also established a new seismic design method of piping systems that allowed support structures to have elasto-plastic behavior. This paper reports the newly developed seismic design method based on the results of experiments conducted under the joint research program of Japanese electric power companies (The Japan Atomic Power Co., Hokkaido EPC, Tohoku EPC, Tokyo EPC, Chubu EPC, Hokuriku EPC, Kansai EPC, Chugoku EPC, Shikoku EPC, Kyushu EPC) and nuclear plant makers (Hitachi Ltd., Toshiba Co., MHI Ltd., HEC Ltd

  12. Orofacial Neuropathic Pain Leads to a Hyporesponsive Barrel Cortex with Enhanced Structural Synaptic Plasticity.

    Science.gov (United States)

    Thibault, Karine; Rivière, Sébastien; Lenkei, Zsolt; Férézou, Isabelle; Pezet, Sophie

    2016-01-01

    Chronic pain is a long-lasting debilitating condition that is particularly difficult to treat due to the lack of identified underlying mechanisms. Although several key contributing processes have been described at the level of the spinal cord, very few studies have investigated the supraspinal mechanisms underlying chronic pain. Using a combination of approaches (cortical intrinsic imaging, immunohistochemical and behavioural analysis), our study aimed to decipher the nature of functional and structural changes in a mouse model of orofacial neuropathic pain, focusing on cortical areas involved in various pain components. Our results show that chronic neuropathic orofacial pain is associated with decreased haemodynamic responsiveness to whisker stimulation in the barrel field cortex. This reduced functional activation is likely due to the increased basal neuronal activity (measured indirectly using cFos and phospho-ERK immunoreactivity) observed in several cortical areas, including the contralateral barrel field, motor and cingulate cortices. In the same animals, immunohistochemical analysis of markers for active pre- or postsynaptic elements (Piccolo and phospho-Cofilin, respectively) revealed an increased immunofluorescence in deep cortical layers of the contralateral barrel field, motor and cingulate cortices. These results suggest that long-lasting orofacial neuropathic pain is associated with exacerbated neuronal activity and synaptic plasticity at the cortical level.

  13. Experience-dependent plasticity in white matter microstructure: Reasoning training alters structural connectivity

    Directory of Open Access Journals (Sweden)

    Allyson P Mackey

    2012-08-01

    Full Text Available Diffusion tensor imaging (DTI techniques have made it possible to investigate white matter plasticity in humans. Changes in DTI measures, principally increases in fractional anisotropy (FA, have been observed following training programs as diverse as juggling, meditation, and working memory. Here, we sought to test whether three months of reasoning training could alter white matter microstructure. We recruited participants (n=23 who were enrolled in a course to prepare for the Law School Admission Test (LSAT, a test that places strong demands on reasoning skills, as well as age- and IQ-matched controls planning to take the LSAT in the future (n=22. DTI data were collected at two scan sessions scheduled three months apart. In trained participants but not controls, we observed decreases in radial diffusivity (RD in white matter connecting frontal cortices, and in mean diffusivity (MD within frontal and parietal lobe white matter. Further, participants exhibiting larger gains on the LSAT exhibited greater decreases in MD in the right internal capsule. In summary, reasoning training altered multiple measures of white matter structure in young adults. While the cellular underpinnings are unknown, these results provide evidence of experience-dependent white matter changes that may not be limited to myelination.

  14. Electrical, thermal and structural properties of plasticized waste cooking oil-based polyurethane solid polymer electrolyte

    Science.gov (United States)

    Huzaizi, Rahmatina Mohd; Tahir, Syuhada Mohd; Mahbor, Kamisah Mohamad

    2017-12-01

    Waste cooking oil-based polyol was synthesized using epoxidation and hydroxylation methods. The polyol was combined with 4,4-diphenylmethane diisocyanate to produce polyurethane (PU) to be used as polymer host in solid polymer electrolyte. 30 wt% LiClO4 was added as doping salt and two types of plasticizers were used; ethylene carbonate (PU-EC) and polyethylene glycol (PU-PEG). The SPE films were characterized using Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The highest conductivity achieved was 8.4 x 10-8 S cm-1 upon addition of 10 wt% EC. The XRD results showed a decrease of crystalline peaks in PU-EC and the increase in PU-PEG. DSC results revealed that the films; PU, PU-EC and PU-PEG had glass transition temperatures of 159.7, 106.0 and 179.7 °C, respectively. The results showed that the addition of EC increased the amorphous region and the free volume in the SPE structure, thus resulted in higher ionic conductivity.

  15. Model-Driven Analysis of Eyeblink Classical Conditioning Reveals the Underlying Structure of Cerebellar Plasticity and Neuronal Activity.

    Science.gov (United States)

    Antonietti, Alberto; Casellato, Claudia; D'Angelo, Egidio; Pedrocchi, Alessandra

    The cerebellum plays a critical role in sensorimotor control. However, how the specific circuits and plastic mechanisms of the cerebellum are engaged in closed-loop processing is still unclear. We developed an artificial sensorimotor control system embedding a detailed spiking cerebellar microcircuit with three bidirectional plasticity sites. This proved able to reproduce a cerebellar-driven associative paradigm, the eyeblink classical conditioning (EBCC), in which a precise time relationship between an unconditioned stimulus (US) and a conditioned stimulus (CS) is established. We challenged the spiking model to fit an experimental data set from human subjects. Two subsequent sessions of EBCC acquisition and extinction were recorded and transcranial magnetic stimulation (TMS) was applied on the cerebellum to alter circuit function and plasticity. Evolutionary algorithms were used to find the near-optimal model parameters to reproduce the behaviors of subjects in the different sessions of the protocol. The main finding is that the optimized cerebellar model was able to learn to anticipate (predict) conditioned responses with accurate timing and success rate, demonstrating fast acquisition, memory stabilization, rapid extinction, and faster reacquisition as in EBCC in humans. The firing of Purkinje cells (PCs) and deep cerebellar nuclei (DCN) changed during learning under the control of synaptic plasticity, which evolved at different rates, with a faster acquisition in the cerebellar cortex than in DCN synapses. Eventually, a reduced PC activity released DCN discharge just after the CS, precisely anticipating the US and causing the eyeblink. Moreover, a specific alteration in cortical plasticity explained the EBCC changes induced by cerebellar TMS in humans. In this paper, for the first time, it is shown how closed-loop simulations, using detailed cerebellar microcircuit models, can be successfully used to fit real experimental data sets. Thus, the changes of the

  16. Automatic Generation of Connectivity for Large-Scale Neuronal Network Models through Structural Plasticity.

    Science.gov (United States)

    Diaz-Pier, Sandra; Naveau, Mikaël; Butz-Ostendorf, Markus; Morrison, Abigail

    2016-01-01

    With the emergence of new high performance computation technology in the last decade, the simulation of large scale neural networks which are able to reproduce the behavior and structure of the brain has finally become an achievable target of neuroscience. Due to the number of synaptic connections between neurons and the complexity of biological networks, most contemporary models have manually defined or static connectivity. However, it is expected that modeling the dynamic generation and deletion of the links among neurons, locally and between different regions of the brain, is crucial to unravel important mechanisms associated with learning, memory and healing. Moreover, for many neural circuits that could potentially be modeled, activity data is more readily and reliably available than connectivity data. Thus, a framework that enables networks to wire themselves on the basis of specified activity targets can be of great value in specifying network models where connectivity data is incomplete or has large error margins. To address these issues, in the present work we present an implementation of a model of structural plasticity in the neural network simulator NEST. In this model, synapses consist of two parts, a pre- and a post-synaptic element. Synapses are created and deleted during the execution of the simulation following local homeostatic rules until a mean level of electrical activity is reached in the network. We assess the scalability of the implementation in order to evaluate its potential usage in the self generation of connectivity of large scale networks. We show and discuss the results of simulations on simple two population networks and more complex models of the cortical microcircuit involving 8 populations and 4 layers using the new framework.

  17. Characteristic structures and properties of nanostructured metals prepared by plastic deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2011-01-01

    This chapter focuses on describing the characteristic microstructures of nanostructured metals produced by plastic deformation to ultrahigh strains and their correlation with hardening by annealing and softening by deformation. The results suggest that optimising microstructure and the mechanical...

  18. A multi-scale model for structure-property relations of materials exhibiting martensite transformation plasticity

    NARCIS (Netherlands)

    Kouznetsova, V.; Balmachnov, A.; Geers, M.G.D.

    2009-01-01

    The remarkable mechanical properties of many advanced steels, e.g. metastable austenitic stainless steels, are related to their complex microstructural behaviour, resulting from the interaction between plastic deformation of the phases and the austenite to martensite phase transformation during

  19. Arsenic levels in wipe samples collected from play structures constructed with CCA-treated wood: Impact on exposure estimates

    Energy Technology Data Exchange (ETDEWEB)

    Barraj, Leila M. [Chemical Regulation and Food Safety, Exponent, Inc., Suite 1100, 1150 Connecticut Ave., NW, Washington, DC 20036 (United States)], E-mail: lbarraj@exponent.com; Scrafford, Carolyn G. [Chemical Regulation and Food Safety, Exponent, Inc., Suite 1100, 1150 Connecticut Ave., NW, Washington, DC 20036 (United States); Eaton, W. Cary [RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709 (United States); Rogers, Robert E.; Jeng, Chwen-Jyh [Toxcon Health Sciences Research Centre Inc., 9607 - 41 Avenue, Edmonton, Alberta, T6E 5X7 (Canada)

    2009-04-01

    Lumber treated with chromated copper arsenate (CCA) has been used in residential outdoor wood structures and playgrounds. The U.S. EPA has conducted a probabilistic assessment of children's exposure to arsenic from CCA-treated structures using the Stochastic Human Exposure and Dose Simulation model for the wood preservative scenario (SHEDS-Wood). The EPA assessment relied on data from an experimental study using adult volunteers and designed to measure arsenic in maximum hand and wipe loadings. Analyses using arsenic handloading data from a study of children playing on CCA-treated play structures in Edmonton, Canada, indicate that the maximum handloading values significantly overestimate the exposure that occurs during actual play. The objective of our paper is to assess whether the dislodgeable arsenic residues from structures in the Edmonton study are comparable to those observed in other studies and whether they support the conclusion that the values derived by EPA using modeled maximum loading values overestimate hand exposures. We compared dislodgeable arsenic residue data from structures in the playgrounds in the Edmonton study to levels observed in studies used in EPA's assessment. Our analysis showed that the dislodgeable arsenic levels in the Edmonton playground structures are similar to those in the studies used by EPA. Hence, the exposure estimates derived using the handloading data from children playing on CCA-treated structures are more representative of children's actual exposures than the overestimates derived by EPA using modeled maximum values. Handloading data from children playing on CCA-treated structures should be used to reduce the uncertainty of modeled estimates derived using the SHEDS-Wood model.

  20. Structural plasticity mediates distinct GAP-dependent GTP hydrolysis mechanisms in Rab33 and Rab5.

    Science.gov (United States)

    Majumdar, Soneya; Acharya, Abhishek; Prakash, Balaji

    2017-12-01

    The classical GTP hydrolysis mechanism, as seen in Ras, employs a catalytic glutamine provided in cis by the GTPase and an arginine supplied in trans by a GTPase activating protein (GAP). The key idea emergent from a large body of research on small GTPases is that GTPases employ a variety of different hydrolysis mechanisms; evidently, these variations permit diverse rates of GTPase inactivation, crucial for temporal regulation of different biological processes. Recently, we unified these variations and argued that a steric clash between active site residues (corresponding to positions 12 and 61 of Ras) governs whether a GTPase utilizes the cis-Gln or the trans-Gln (from the GAP) for catalysis. As the cis-Gln encounters a steric clash, the Rab GTPases employ the so-called dual finger mechanism where the interacting GAP supplies a trans-Gln for catalysis. Using experimental and computational methods, we demonstrate how the cis-Gln of Rab33 overcomes the steric clash when it is stabilized by a residue in the vicinity. In effect, this demonstrates how both cis-Gln- and trans-Gln-mediated mechanisms could operate in the same GTPase in different contexts, i.e. depending on the GAP that regulates its action. Interestingly, in the case of Rab5, which possesses a higher intrinsic GTP hydrolysis rate, a similar stabilization of the cis-Gln appears to overcome the steric clash. Taken together with the mechanisms seen for Rab1, it is evident that the observed variations in Rab and their GAP partners allow structural plasticity, or in other words, the choice of different catalytic mechanisms. © 2017 Federation of European Biochemical Societies.

  1. Structural and mechanical behaviour of severe plastically deformed high purity aluminium sheets processed by constrained groove pressing technique

    International Nuclear Information System (INIS)

    Satheesh Kumar, S.S.; Raghu, T.

    2014-01-01

    Highlights: • High purity aluminium sheets constrained groove pressed up to plastic strain of 5.8. • Microstructural evolution studied by TEM and X-ray diffraction profile analysis. • Ultrafine grained structure with grain size ∼900 nm achieved in sheets. • Yield strength increased by 5.3 times and tensile strength doubled after first pass. • Enhanced deformation homogeneity seen with increased accumulated plastic strain. - Abstract: High purity aluminium sheets (∼99.9%) are subjected to intense plastic straining by constrained groove pressing method successfully up to 5 passes thereby imparting an effective plastic strain of 5.8. Transmission electron microscopy studies of constrained groove pressed sheets divulged significant grain refinement and the average grain sizes obtained after five pass is estimated to be ∼0.9 μm. In addition to that, microstructural evolution of constrained groove pressed sheets is characterized by X-ray diffraction peak profile analysis employing Williamson–Hall method and the results obtained fairly concur with electron microscopy findings. The tensile behaviour evolution with increased straining indicates substantial improvement of yield strength by ∼5.3 times from 17 MPa to 90 MPa during first pass corroborated to grain refinement observed. Marginal increase in strengths is noticed during second pass followed by minor drop in strengths attributed to predominance of dislocation recovery is noticed in subsequent passes. Quantitative assessment of degree of deformation homogeneity using microhardness profiles reveal relatively better strain homogeneity at higher number of passes

  2. On the application of the dynamic plasticity theory for the treatment of reinforced concrete structures under transient loading

    International Nuclear Information System (INIS)

    Ammann, W.

    1983-01-01

    After a short introduction of the theory of dynamic plasticity, the possible applications of this theory on reinforced concrete structures under transient loading are discussed. Estimates can be obtained by relations giving lower and upper limits for dynamically loaded supporting beams. A procedure similar for the mode approximation method is described for the calculation of beams after a sudden failure of a support. (orig.) [de

  3. Structure from Motion (SfM) photogrammetry applied to historical imagery: plug & play?

    Science.gov (United States)

    Bakker, Maarten; Lane, Stuart N.

    2017-04-01

    The development of Structure from Motion (SfM) photogrammetry has led to a vast increase and expansion of geomorphological applications. Highly detailed Digital Elevation Models (DEMs) can be efficiently generated from a variety of platforms that cover a large range of spatial scales. For the application of DEMs in geomorphic change analysis, precision and spatial resolution are not of sole importance, but also their accuracy, temporal resolution and temporal coverage. The use of archival imagery may substantially lengthen temporal coverage, allowing quantification of annual to decadal scale landform change. Whilst archival photogrammetry is not new, a question arises as to how applicable SfM methods are as a more cost-effective and straightforward alternative to the conventional approach. Here, we studied a relatively extreme case where we applied SfM techniques to archival aerial imagery, to investigate the decadal evolution of a low relief braided river. The Borgne is an Alpine river in south-west Switzerland which is strongly affected by flow abstraction for hydropower, allowing the fairly straightforward application of photogrammetry on the near-dry river bed. For 8 sets of scanned historical aerial images in the period 1959-2005 we performed Ground Control Point (GCP) assisted bundle adjustment using both classical archival digital photogrammetry (used as a reference dataset) and SfM based photogrammetry. For the SfM method, no further data were used to constrain camera or exterior orientation parameters a priori, but instead we used these for a posteriori verification. The resulting densified point clouds were registered onto a reference surface based on stable areas, allowing the correction for any systematic error in DEMs that may arise from (random) error in the bundle adjustment. The obtained results show that the quality of the SfM based bundle adjustment is similar to that of the classical photogrammetric approach. Next to image scale, the quality is

  4. Elastic-plastic code in the static regime for two-dimensional structures

    International Nuclear Information System (INIS)

    Giuliani, S.

    1976-07-01

    The finite-element computer code STEP-2D, which was conceived as a numerical tool for basic research in fracture mechanics presently under way in the Materials Division of JRC Ispra is described. The code employs 8-node isoparametric elements for calculating elastic-plastic stress and strain distributions in 2-D geometries. The von Mises yield criterion is used. Material strain hardening is described by means of either the isotropic or the so-called 'overlay' model. An incremental solution is employed in the plastic range. The program has been written in Fortran IV and compiled on an IBM 370-165

  5. Elastic-plastic deformation of fiber composites with a tetragonal structure

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, E.IU.; Svistkova, L.A. (Permskii Politekhnicheskii Institut, Perm (USSR))

    1991-02-01

    Results of numerical solutions are presented for elastic-plastic problems concerning arbitrary loading of unidirectional composites in the transverse plane. The nucleation and evolution of microplastic zones in the matrix and the effect of this process on the macroscopic characteristics of the composite are discussed. Attention is also given to the effect of the fiber shape on the elastic-plastic deformation of the matrix and to deformation paths realized in simple microdeformation processes. The discussion is illustrated by results obtained for a composite consisting of a VT1-0 titanium alloy matrix reinforced by Ti-Mo fibers.

  6. [Application of biodegradable plastic film to reduce plastic film residual pollution in Chinese agriculture].

    Science.gov (United States)

    Yan, Changrong; He, Wenqing; Xue, Yinghao; Liu, Enke; Liu, Qin

    2016-06-25

    Plastic film has become an important agriculture production material in recent years. Over the past three decades, the amount and application area of plastic film have increased steadily, and in 2014, which are 1.4 million tons and more than 180 million hm² respectively. It plays a key role for ensuring the supply of agricultural goods in China. Meanwhile, plastic film residual pollution becomes more and more serious, and in some regions, the amount of plastic film residues has reached over 250 kg/hm². In part of the Northwest region, soil structure of farmland has been destroyed by plastic film residues and then crop growth and farming operations were suppressed. It is recognized as a good choice to replace plastic film with biodegradable plastic film, an effective measure to solve the plastic film residue pollution. Now, it is in a critical stage of study and assessment of biodegradable plastic film in China and fortunately some biodegradable plastic films show effects in the production of potatoes, peanuts and tobacco. Overall, a series of challenges has still been faced by the biodegradable plastic film, mainly including improving the quality of biodegradable plastic products, such as tensile strength, flexibility, improving the controllability of rupture and degradation, enhancing the ability of increasing soil temperature and preserving soil moisture, and to satisfy the demand of crops production with mulching. In addition, it is essential to reduce the cost of the biodegradable film and promote the application of biodegradable film on large-scale. With the development of biodegradable plastic technology and agricultural production environment, the application of the biodegradable film will have a good future.

  7. Finite element elasto-plastic analysis of thin walled structures of reinforced concrete as applied to reactor facilities

    International Nuclear Information System (INIS)

    Fujita, F.; Tsuboi, Y.

    1981-01-01

    The authors developed a new program of elasto-plastic analysis of reinforced concrete shells, in which the simplest model of shell element and an orthotropic constitutive relation are adopted, and verified its validity with reference to the results of model experiments of containers and box-wall structures with various loading conditions. For the two-dimensional stress-strain relationship of concrete, an orthotropic nonlinear formula proposed by one of the authors was adopted. For concrete, the octahedral shear failure and tension cut-off criteria were also imposed. The Kirchhoff-Love's assumptions were assumed to be valid for the whole range of the analysis and the layered approach of elasto-plastic stiffness evaluation. Derivation of the shell element is outlined with examination of its accuracy in elastic range and the assumption of elasto-plastic material property and the procedure of nonlinear analysis are described. As examples, the method is applied to the analysis of a cylindrical container and a box-wall structure. Comparison of the computed results with the corresponding experimental data indicates the applicability of the proposed method. (orig./HP)

  8. Plasticity detection and quantification in monopile support structures due to axial impact loading

    NARCIS (Netherlands)

    Meijers, P.C.; Tsouvalas, A.; Metrikine, A.

    2018-01-01

    Recent developments in the construction of offshore wind turbines have created the need for a method to detect whether a monopile foundation is plastically deformed during the installation procedure. Since measurements at the pile head are difficult to perform, a method based on measurements at a

  9. Modelling of the stiffness evolution of truss core structures damaged by plastic buckling

    Czech Academy of Sciences Publication Activity Database

    Šiška, Filip; Stratil, Luděk; Dlouhý, Ivo; Barnett, M.R.

    2015-01-01

    Roč. 100, AUG (2015), s. 1-11 ISSN 0168-874X R&D Projects: GA MŠk EE2.3.20.0197 Institutional support: RVO:68081723 Keywords : beam theory * plastic buckling * finite element * beam-columns * truss-coredlaminates Subject RIV: JI - Composite Materials Impact factor: 2.175, year: 2015

  10. A plastic stress intensity factor approach to turbine disk structural integrity assessment

    Directory of Open Access Journals (Sweden)

    V. Shlyannikov

    2016-07-01

    Full Text Available This study based on a new fracture mechanics parameter is concerned with assessing the integrity of cracked steam turbine disk which operate under startup-shutdown cyclic loading conditions. Damage accumulation and growth in service have occurred on the inner surface of slot fillet of key. In order to determine elastic-plastic fracture mechanics parameters full-size stress-strain state analysis of turbine disk was performed for a quote-elliptical part-through cracks under considering loading conditions. As a result distributions of elastic and plastic stress intensity factors along crack front in slot fillet of key of turbine disk depending on surface crack form are defined. An engineering approach to the prediction of carrying capacity of cracked turbine disk which is sensitive to the loading history at maintenance is proposed. The predictions of the rate of crack growth and residual lifetime of steam turbine disk are compared for elastic and elastic-plastic solutions. It is shown that the previously proposed elastic crack growth models provide overestimate the lifetime with respect to the present one. An advantage to use the plastic stress intensity factor to characterize the fracture resistance as the self-dependent unified parameter for a variety of turbine disk configurations rather than the magnitude of the elastic stress intensity factors alone is discussed.

  11. Structural evaluation method for class 1 vessels by using elastic-plastic finite element analysis in code case of JSME rules on design and construction

    International Nuclear Information System (INIS)

    Asada, Seiji; Hirano, Takashi; Nagata, Tetsuya; Kasahara, Naoto

    2008-01-01

    A structural evaluation method by using elastic-plastic finite element analysis has been developed and published as a code case of Rules on Design and Construction for Nuclear Power Plants (The First Part: Light Water Reactor Structural Design Standard) in the JSME Codes for Nuclear Power Generation Facilities. Its title is 'Alternative Structural Evaluation Criteria for Class 1 Vessels Based on Elastic-Plastic Finite Element Analysis' (NC-CC-005). This code case applies elastic-plastic analysis to evaluation of such failure modes as plastic collapse, thermal ratchet, fatigue and so on. Advantage of this evaluation method is free from stress classification, consistently use of Mises stress and applicability to complex 3-dimensional structures which are hard to be treated by the conventional stress classification method. The evaluation method for plastic collapse has such variation as the Lower Bound Approach Method, Twice-Elastic-Slope Method and Elastic Compensation Method. Cyclic Yield Area (CYA) based on elastic analysis is applied to screening evaluation of thermal ratchet instead of secondary stress evaluation, and elastic-plastic analysis is performed when the CYA screening criteria is not satisfied. Strain concentration factors can be directly calculated based on elastic-plastic analysis. (author)

  12. Determination of the structural changes by Raman and {sup 13}C CP/MAS NMR spectroscopy on native corn starch with plasticizers

    Energy Technology Data Exchange (ETDEWEB)

    Cozar, O. [Academy of Romanian Scientists, Splaiul Independentei 54, 050094, Bucharest, Romania and National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch (Romania); Filip, C.; Tripon, C. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Cioica, N.; Coţa, C.; Nagy, E. M. [National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch, RO-400458 Cluj-Napoca (Romania)

    2013-11-13

    The plasticizing - antiplasticizing effect of water and glycerol contents on native corn starch samples is investigated by FT-Raman and {sup 13}C CP/MAS NMR spectroscopy. The presence of both amorphous and crystalline structural phases was evidenced in pure native corn starch and also in the samples containing plasticizers. Among the crystalline starch structures, the A- and V- types were suggested by CP/MAS NMR spectra.

  13. Structuring collaboration scripts for mastership skills: Optimizing online group play on classroom dilemmas in teacher education

    NARCIS (Netherlands)

    Hummel, Hans; Geerts, Walter; Slootmaker, Aad; Kuipers, Derek; Westera, Wim

    2014-01-01

    Serious games can facilitate workplace learning, for instance when collaboration on solving professional problems is involved. The optimal structure in collaboration scripts for such games has appeared to be a key success factor. Free collaboration does not systematically produce effective

  14. The use of standardized patients in the plastic surgery residency curriculum: teaching core competencies with objective structured clinical examinations.

    Science.gov (United States)

    Davis, Drew; Lee, Gordon

    2011-07-01

    As of 2006, the Accreditation Council for Graduate Medical Education had defined six "core competencies" of residency education: interpersonal communication skills, medical knowledge, patient care, professionalism, practice-based learning and improvement, and systems-based practice. Objective structured clinical examinations using standardized patients are becoming effective educational tools, and the authors developed a novel use of the examinations in plastic surgery residency education that assesses all six competencies. Six plastic surgery residents, two each from postgraduate years 4, 5, and 6, participated in the plastic surgery-specific objective structured clinical examination that focused on melanoma. The examination included a 30-minute videotaped encounter with a standardized patient actor and a postencounter written exercise. The residents were scored on their performance in all six core competencies by the standardized patients and faculty experts on a three-point scale (1 = novice, 2 = moderately skilled, and 3 = proficient). Resident performance was averaged for each postgraduate year, stratified according to core competency, and scored from a total of 100 percent. Residents overall scored well in interpersonal communications skills (84 percent), patient care (83 percent), professionalism (86 percent), and practice-based learning (84 percent). Scores in medical knowledge showed a positive correlation with level of training (86 percent). All residents scored comparatively lower in systems-based practice (65 percent). The residents reported unanimously that the objective structured clinical examination was realistic and educational. The objective structured clinical examination provided comprehensive and meaningful feedback and identified areas of strengths and weakness for the residents and for the teaching program. The examination is an effective assessment tool for the core competencies and a valuable adjunct to residency training.

  15. Spatially resolved analysis of short-range structure perturbations in a plastically bent molecular crystal

    Science.gov (United States)

    Panda, Manas K.; Ghosh, Soumyajit; Yasuda, Nobuhiro; Moriwaki, Taro; Mukherjee, Goutam Dev; Reddy, C. Malla; Naumov, Panče

    2015-01-01

    The exceptional mechanical flexibility observed with certain organic crystals defies the common perception of single crystals as brittle objects. Here, we describe the morphostructural consequences of plastic deformation in crystals of hexachlorobenzene that can be bent mechanically at multiple locations to 360° with retention of macroscopic integrity. This extraordinary plasticity proceeds by segregation of the bent section into flexible layers that slide on top of each other, thereby generating domains with slightly different lattice orientations. Microscopic, spectroscopic and diffraction analyses of the bent crystal showed that the preservation of crystal integrity when stress is applied on the (001) face requires sliding of layers by breaking and re-formation of halogen-halogen interactions. Application of stress on the (100) face, in the direction where π···π interactions dominate the packing, leads to immediate crystal disintegration. Within a broader perspective, this study highlights the yet unrecognized extraordinary malleability of molecular crystals with strongly anisotropic supramolecular interactions.

  16. A plastic stress intensity factor approach to turbine disk structural integrity assessment

    OpenAIRE

    Shlyannikov, V.; Zakharov, A.; Yarullin, R.

    2016-01-01

    This study based on a new fracture mechanics parameter is concerned with assessing the integrity of cracked steam turbine disk which operate under startup-shutdown cyclic loading conditions. Damage accumulation and growth in service have occurred on the inner surface of slot fillet of key. In order to determine elastic-plastic fracture mechanics parameters full-size stress-strain state analysis of turbine disk was performed for a quote-elliptical part-through cracks under consider...

  17. Effect of Sorbitol Plasticizer on the Structure and Properties of Melt Processed Polyvinyl Alcohol Films.

    Science.gov (United States)

    Tian, Huafeng; Liu, Di; Yao, Yuanyuan; Ma, Songbai; Zhang, Xing; Xiang, Aimin

    2017-12-01

    Poly (vinyl alcohol) (PVA) possesses wide applications as food packaging materials, but is difficult to melt process for its strong inter/intra hydrogen bonding. In this work, flexible PVA films with different content of sorbitol plasticizers were prepared by melt processing with the assistance of water. And the influence of sorbitol plasticizer content on the crystallinity, optical transparency, water-retaining capability, mechanical properties, thermal stability and oxygen and water permeability were investigated. The results indicated that sorbitol dramatically improved the melt processing ability of PVA. Sorbitol could interact with PVA to form strong hydrogen bonding interactions, which would decrease the original hydrogen bonding of the matrix, resulting in the decrease of crystallinity degrees. The glass transition, melting and crystallization peak temperatures decreased with the increase of sorbitol. All the films exhibited fine optical transparency. The water retaining capability were improved with the increase of sorbitol. Especially, an increase in elongation at break and decrease in Young's modulus and tensile strength were observed indicating good plasticizing effect of sorbitol on PVA films. In addition, the PVA films prepared in this work exhibited fine barrier properties against oxygen and water, suggesting wide application potential as packaging materials. © 2017 Institute of Food Technologists®.

  18. Biodegradability of Plastics

    Directory of Open Access Journals (Sweden)

    Yutaka Tokiwa

    2009-08-01

    Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  19. Biodegradability of plastics.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  20. The Interplay between Real Money Trade and Narrative Structure in Massively Multiplayer Online Role-Playing Games

    Directory of Open Access Journals (Sweden)

    Byungchul Park

    2017-01-01

    Full Text Available A narrative structure is one of the main components to constitute the genre of Massively Multiplayer Online Role-Playing Games (MMORPGs. Meanwhile Real Money Trade (RMT enables a player to adjust an ex post level of challenge by skipping the narrative structure of a game. However, RMT may concurrently disturb a player who enjoys game following the narrative structure hierarchically. In pursuance of developing the knowledge about the relationship between RMT and the usage of MMORPG, we investigate the role of the strictness of predetermined narrative structure. We present the dual structure of societies to describe a player that arbitrarily decides to reside in a virtual society. Then we adopt the social nominalism to explain how individual motif of playing a game is expanded to the nature of game. Finally, we argue that a game with weakly predetermined narrative structure is more positively associated with RMT volume, since these games arouse a player’s sentiment of fun by relying more on their socially oriented motivation. With empirical evidence from the Korean MMORPGs market, we proved the hypothesis.

  1. Sodium Channel Voltage-Gated Beta 2 Plays a Vital Role in Brain Aging Associated with Synaptic Plasticity and Expression of COX5A and FGF-2.

    Science.gov (United States)

    XiYang, Yan-Bin; Wang, You-Cui; Zhao, Ya; Ru, Jin; Lu, Bing-Tuan; Zhang, Yue-Ning; Wang, Nai-Chao; Hu, Wei-Yan; Liu, Jia; Yang, Jin-Wei; Wang, Zhao-Jun; Hao, Chun-Guang; Feng, Zhong-Tang; Xiao, Zhi-Cheng; Dong, Wei; Quan, Xiong-Zhi; Zhang, Lian-Feng; Wang, Ting-Hua

    2016-03-01

    The role of sodium channel voltage-gated beta 2 (SCN2B) in brain aging is largely unknown. The present study was therefore designed to determine the role of SCN2B in brain aging by using the senescence-accelerated mice prone 8 (SAMP8), a brain senescence-accelerated animal model, together with the SCN2B transgenic mice. The results showed that SAMP8 exhibited impaired learning and memory functions, assessed by the Morris water maze test, as early as 8 months of age. The messenger RNA (mRNA) and protein expressions of SCN2B were also upregulated in the prefrontal cortex at this age. Treatment with traditional Chinese anti-aging medicine Xueshuangtong (Panax notoginseng saponins, PNS) significantly reversed the SCN2B expressions in the prefrontal cortex, resulting in improved learning and memory. Moreover, SCN2B knockdown transgenic mice were generated and bred to determine the roles of SCN2B in brain senescence. A reduction in the SCN2B level by 60.68% resulted in improvement in the hippocampus-dependent spatial recognition memory and long-term potential (LTP) slope of field excitatory postsynaptic potential (fEPSP), followed by an upregulation of COX5A mRNA levels and downregulation of fibroblast growth factor-2 (FGF-2) mRNA expression. Together, the present findings indicated that SCN2B could play an important role in the aging-related cognitive deterioration, which is associated with the regulations of COX5A and FGF-2. These findings could provide the potential strategy of candidate target to develop antisenescence drugs for the treatment of brain aging.

  2. Relationship between structural brainstem and brain plasticity and lower-limb training in spinal cord injury: a longitudinal pilot study

    Directory of Open Access Journals (Sweden)

    Michael eVilliger

    2015-05-01

    Full Text Available Rehabilitative training has shown to improve significantly motor outcomes and functional walking capacity in patients with incomplete spinal cord injury (iSCI. However, whether performance improvements during rehabilitation relate to brain plasticity or whether it is based on functional adaptation of movement strategies remain uncertain. This study assessed training improvement-induced structural brain plasticity in chronic iSCI patients using longitudinal MRI.We used tensor-based morphometry (TBM to analyze longitudinal brain volume changes associated with intensive virtual reality (VR-augmented lower limb training in nine traumatic iSCI patients. The MRI data was acquired before and after a 4-week training period (16-20 training sessions. Before training, voxel-based morphometry (VBM and voxel-based cortical thickness (VBCT assessed baseline morphometric differences in nine iSCI patients compared to 14 healthy controls. The intense VR-augmented training of limb control improved significantly balance, walking speed, ambulation, and muscle strength in patients. Retention of clinical improvements was confirmed by the 3-4 months follow-up. In patients relative to controls, reductions in VBM of white matter volume within the brainstem and cerebellum and VBCT showed cortical thinning in the primary motor cortex. Over time, TBM revealed significant improvement-induced increases in the left middle temporal and occipital gyrus, left temporal pole and fusiform gyrus, both hippocampi, cerebellum, corpus callosum, and brainstem in iSCI patients. This study demonstrates structural plasticity at the cortical and brainstem level as a consequence of VR-augmented training in iSCI patients. These structural changes may serve as neuroimaging biomarkers of VR-augmented lower limb neurorehabilitation in addition to performance measures to detect improvements in rehabilitative training.

  3. Relationship between structural brainstem and brain plasticity and lower-limb training in spinal cord injury: a longitudinal pilot study

    Science.gov (United States)

    Villiger, Michael; Grabher, Patrick; Hepp-Reymond, Marie-Claude; Kiper, Daniel; Curt, Armin; Bolliger, Marc; Hotz-Boendermaker, Sabina; Kollias, Spyros; Eng, Kynan; Freund, Patrick

    2015-01-01

    Rehabilitative training has shown to improve significantly motor outcomes and functional walking capacity in patients with incomplete spinal cord injury (iSCI). However, whether performance improvements during rehabilitation relate to brain plasticity or whether it is based on functional adaptation of movement strategies remain uncertain. This study assessed training improvement-induced structural brain plasticity in chronic iSCI patients using longitudinal MRI. We used tensor-based morphometry (TBM) to analyze longitudinal brain volume changes associated with intensive virtual reality (VR)-augmented lower limb training in nine traumatic iSCI patients. The MRI data was acquired before and after a 4-week training period (16–20 training sessions). Before training, voxel-based morphometry (VBM) and voxel-based cortical thickness (VBCT) assessed baseline morphometric differences in nine iSCI patients compared to 14 healthy controls. The intense VR-augmented training of limb control improved significantly balance, walking speed, ambulation, and muscle strength in patients. Retention of clinical improvements was confirmed by the 3–4 months follow-up. In patients relative to controls, VBM revealed reductions of white matter volume within the brainstem and cerebellum and VBCT showed cortical thinning in the primary motor cortex. Over time, TBM revealed significant improvement-induced volume increases in the left middle temporal and occipital gyrus, left temporal pole and fusiform gyrus, both hippocampi, cerebellum, corpus callosum, and brainstem in iSCI patients. This study demonstrates structural plasticity at the cortical and brainstem level as a consequence of VR-augmented training in iSCI patients. These structural changes may serve as neuroimaging biomarkers of VR-augmented lower limb neurorehabilitation in addition to performance measures to detect improvements in rehabilitative training. PMID:25999842

  4. Play Matters

    DEFF Research Database (Denmark)

    Sicart (Vila), Miguel Angel

    ? In Play Matters, Miguel Sicart argues that to play is to be in the world; playing is a form of understanding what surrounds us and a way of engaging with others. Play goes beyond games; it is a mode of being human. We play games, but we also play with toys, on playgrounds, with technologies and design......, but not necessarily fun. Play can be dangerous, addictive, and destructive. Along the way, Sicart considers playfulness, the capacity to use play outside the context of play; toys, the materialization of play--instruments but also play pals; playgrounds, play spaces that enable all kinds of play; beauty...

  5. The nano-structured battery plays extra time; La batterie nanostructuree joue les prolongations

    Energy Technology Data Exchange (ETDEWEB)

    Deroin, Ph.

    2005-06-01

    The Bell Labs of Lucent Technologies and the laboratories of mPhase company (Connecticut, USA) have developed a new architecture of battery cell based on nano-structured material which should lead to a 15 to 20 years lifetime without any significant discharge. In this structure, the electrolyte (zinc and ammonium chlorides) and the electrodes (Zn, MnO{sub 2}) are not in contact as long as the battery is not activated. A fluorocarbon hydrophobic coating (the 'nano-metric grass') ensures the separation between electrolyte and electrodes. This hydrophobic effect can be instantaneously cancelled by an electric pulse which provokes an electro-wetting effect allowing the migration of the electrolyte towards the electrodes. Short paper. (J.S.)

  6. Plastic Surgery

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Plastic Surgery KidsHealth / For Teens / Plastic Surgery What's in ... her forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word " ...

  7. CENP-W plays a role in maintaining bipolar spindle structure.

    Directory of Open Access Journals (Sweden)

    Agnieszka Kaczmarczyk

    Full Text Available The CENP-W/T complex was previously reported to be required for mitosis. HeLa cells depleted of CENP-W displayed profound mitotic defects, with mitotic timing delay, disorganized prometaphases and multipolar spindles as major phenotypic consequences. In this study, we examined the process of multipolar spindle formation induced by CENP-W depletion. Depletion of CENP-W in HeLa cells labeled with histone H2B and tubulin fluorescent proteins induced rapid fragmentation of originally bipolar spindles in a high proportion of cells. CENP-W depletion was associated with depletion of Hec1 at kinetochores. The possibility of promiscuous centrosomal duplication was ruled out by immunofluorescent examination of centrioles. However, centrioles were frequently observed to be abnormally split. In addition, a large proportion of the supernumerary poles lacked centrioles, but were positively stained with different centrosomal markers. These observations suggested that perturbation in spindle force distribution caused by defective kinetochores could contribute to a mechanical mechanism for spindle pole disruption. 'Spindle free' nocodazole arrested cells did not exhibit pole fragmentation after CENP-W depletion, showing that pole fragmentation is microtubule dependent. Inhibition of centrosome separation by monastrol reduced the incidence of spindle pole fragmentation, indicating that Eg5 plays a role in spindle pole disruption. Surprisingly, CENP-W depletion rescued the monopolar spindle phenotype of monastrol treatment, with an increased frequency of bipolar spindles observed after CENP-W RNAi. We overexpressed the microtubule cross-linking protein TPX2 to create spindle poles stabilized by the microtubule cross-linking activity of TPX2. Spindle pole fragmentation was suppressed in a TPX2-dependent fashion. We propose that CENP-W, by influencing proper kinetochore assembly, particularly microtubule docking sites, can confer spindle pole resistance to traction

  8. CENP-W Plays a Role in Maintaining Bipolar Spindle Structure

    Science.gov (United States)

    Kaczmarczyk, Agnieszka; Sullivan, Kevin F.

    2014-01-01

    The CENP-W/T complex was previously reported to be required for mitosis. HeLa cells depleted of CENP-W displayed profound mitotic defects, with mitotic timing delay, disorganized prometaphases and multipolar spindles as major phenotypic consequences. In this study, we examined the process of multipolar spindle formation induced by CENP-W depletion. Depletion of CENP-W in HeLa cells labeled with histone H2B and tubulin fluorescent proteins induced rapid fragmentation of originally bipolar spindles in a high proportion of cells. CENP-W depletion was associated with depletion of Hec1 at kinetochores. The possibility of promiscuous centrosomal duplication was ruled out by immunofluorescent examination of centrioles. However, centrioles were frequently observed to be abnormally split. In addition, a large proportion of the supernumerary poles lacked centrioles, but were positively stained with different centrosomal markers. These observations suggested that perturbation in spindle force distribution caused by defective kinetochores could contribute to a mechanical mechanism for spindle pole disruption. ‘Spindle free’ nocodazole arrested cells did not exhibit pole fragmentation after CENP-W depletion, showing that pole fragmentation is microtubule dependent. Inhibition of centrosome separation by monastrol reduced the incidence of spindle pole fragmentation, indicating that Eg5 plays a role in spindle pole disruption. Surprisingly, CENP-W depletion rescued the monopolar spindle phenotype of monastrol treatment, with an increased frequency of bipolar spindles observed after CENP-W RNAi. We overexpressed the microtubule cross-linking protein TPX2 to create spindle poles stabilized by the microtubule cross-linking activity of TPX2. Spindle pole fragmentation was suppressed in a TPX2-dependent fashion. We propose that CENP-W, by influencing proper kinetochore assembly, particularly microtubule docking sites, can confer spindle pole resistance to traction forces exerted

  9. Structure-property relation in HPMC polymer films plasticized with Sorbitol

    Science.gov (United States)

    Prakash, Y.; Somashekarappa, H.; Mahadevaiah, Somashekar, R.

    2013-06-01

    A correlation study on physical and mechanical properties of Hydroxy propyl-methylcellulose (HPMC) polymer films plasticized with different weight ratio of Sorbitol, prepared using solution casting method, was carried out using wide angle X-ray technique and universal testing machine. It is found that the crystallanity decreases as the concentration of Sorbitol increases up to a certain concentration and there afterwards increases. Measured Physical Properties like tensile strength decreases and elongation (%) increases indicating increase in the flexibility of the films. These observations confirm the correlation between microstructal parameters and mechanical properties of films. These films are suitable for packaging food products.

  10. Simplified elastic-plastic analysis of reinforced concrete structures - design method for self-restraining stress

    International Nuclear Information System (INIS)

    Aihara, S.; Atsumi, K.; Ujiie, K.; Satoh, S.

    1981-01-01

    Self-restraining stresses generate not only moments but also axial forces. Therefore the moment and force equilibriums of cross section are considered simultaneously, in combination with other external forces. Thus, under this theory, two computer programs are prepared for. Using these programs, the design procedures which considered the reduction of self-restraining stress, become easy if the elastic design stresses, which are separated normal stresses and self-restraining stresses, are given. Numerical examples are given to illustrate the application of the simplified elastic-plastic analysis and to study its effectiveness. First this method is applied to analyze an upper shielding wall in MARK-2 type's Reactor building. The results are compared with those obtained by the elastic-plastic analysis of Finite Element Method. From this comparison it was confirmed that the method described, had adequate accuracy for re-bar design. As a second example, Mat slab of Reactor building is analyzed. The quantity of re-bars calculated by this method, comes to about two third of re-bars less than those required when self-restraining stress is considered as normal stress. Also, the self-restraining stress reduction factor is about 0.5. (orig./HP)

  11. When Music and Long-Term Memory Interact: Effects of Musical Expertise on Functional and Structural Plasticity in the Hippocampus

    Science.gov (United States)

    Groussard, Mathilde; La Joie, Renaud; Rauchs, Géraldine; Landeau, Brigitte; Chételat, Gaël; Viader, Fausto; Desgranges, Béatrice; Eustache, Francis; Platel, Hervé

    2010-01-01

    The development of musical skills by musicians results in specific structural and functional modifications in the brain. Surprisingly, no functional magnetic resonance imaging (fMRI) study has investigated the impact of musical training on brain function during long-term memory retrieval, a faculty particularly important in music. Thus, using fMRI, we examined for the first time this process during a musical familiarity task (i.e., semantic memory for music). Musical expertise induced supplementary activations in the hippocampus, medial frontal gyrus, and superior temporal areas on both sides, suggesting a constant interaction between episodic and semantic memory during this task in musicians. In addition, a voxel-based morphometry (VBM) investigation was performed within these areas and revealed that gray matter density of the hippocampus was higher in musicians than in nonmusicians. Our data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity in the hippocampus. PMID:20957158

  12. When music and long-term memory interact: effects of musical expertise on functional and structural plasticity in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Mathilde Groussard

    Full Text Available The development of musical skills by musicians results in specific structural and functional modifications in the brain. Surprisingly, no functional magnetic resonance imaging (fMRI study has investigated the impact of musical training on brain function during long-term memory retrieval, a faculty particularly important in music. Thus, using fMRI, we examined for the first time this process during a musical familiarity task (i.e., semantic memory for music. Musical expertise induced supplementary activations in the hippocampus, medial frontal gyrus, and superior temporal areas on both sides, suggesting a constant interaction between episodic and semantic memory during this task in musicians. In addition, a voxel-based morphometry (VBM investigation was performed within these areas and revealed that gray matter density of the hippocampus was higher in musicians than in nonmusicians. Our data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity in the hippocampus.

  13. An Optimized Elasto-Plastic Subgrade Reaction For Modeling The Response Of A Nonlinear Foundation For A Structural Analysis

    Directory of Open Access Journals (Sweden)

    Ray Richard Paul

    2015-09-01

    Full Text Available Geotechnical and structural engineers are faced with a difficult task when their designs interact with each other. For complex projects, this is more the norm than the exception. In order to help bridge that gap, a method for modeling the behavior of a foundation using a simple elasto-plastic subgrade reaction was developed. The method uses an optimization technique to position 4-6 springs along a pile foundation to produce similar load deflection characteristics that were modeled by more sophisticated geotechnical finite element software. The methodology uses an Excel spreadsheet for accepting user input and delivering an optimized subgrade spring stiffness, yield, and position along the pile. In this way, the behavior developed from the geotechnical software can be transferred to the structural analysis software. The optimization is achieved through the solver add-in within Excel. Additionally, a beam on a nonlinear elastic foundation model is used to compute deflections of the optimized subgrade reaction configuration.

  14. When music and long-term memory interact: effects of musical expertise on functional and structural plasticity in the hippocampus.

    Science.gov (United States)

    Groussard, Mathilde; La Joie, Renaud; Rauchs, Géraldine; Landeau, Brigitte; Chételat, Gaël; Viader, Fausto; Desgranges, Béatrice; Eustache, Francis; Platel, Hervé

    2010-10-05

    The development of musical skills by musicians results in specific structural and functional modifications in the brain. Surprisingly, no functional magnetic resonance imaging (fMRI) study has investigated the impact of musical training on brain function during long-term memory retrieval, a faculty particularly important in music. Thus, using fMRI, we examined for the first time this process during a musical familiarity task (i.e., semantic memory for music). Musical expertise induced supplementary activations in the hippocampus, medial frontal gyrus, and superior temporal areas on both sides, suggesting a constant interaction between episodic and semantic memory during this task in musicians. In addition, a voxel-based morphometry (VBM) investigation was performed within these areas and revealed that gray matter density of the hippocampus was higher in musicians than in nonmusicians. Our data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity in the hippocampus.

  15. Ripples Make Waves: Binding Structured Activity and Plasticity in Hippocampal Networks

    Directory of Open Access Journals (Sweden)

    Josef H. L. P. Sadowski

    2011-01-01

    Full Text Available Establishing novel episodic memories and stable spatial representations depends on an exquisitely choreographed, multistage process involving the online encoding and offline consolidation of sensory information, a process that is largely dependent on the hippocampus. Each step is influenced by distinct neural network states that influence the pattern of activation across cellular assemblies. In recent years, the occurrence of hippocampal sharp wave ripple (SWR oscillations has emerged as a potentially vital network phenomenon mediating the steps between encoding and consolidation, both at a cellular and network level by promoting the rapid replay and reactivation of recent activity patterns. Such events facilitate memory formation by optimising the conditions for synaptic plasticity to occur between contingent neural elements. In this paper, we explore the ways in which SWRs and other network events can bridge the gap between spatiomnemonic processing at cellular/synaptic and network levels in the hippocampus.

  16. Development of a Quartz Crystal Microbalance Sensor Modified by Nano-Structured Polyaniline for Detecting the Plasticizer in Gaseous State

    Directory of Open Access Journals (Sweden)

    Hui XU

    2014-01-01

    Full Text Available A quartz crystal microbalance (QCM modified by a film of nano-structured polyaniline (nano-PANI is developed as a gas sensor for detecting the presence of the plasticizer, such as dibutyl phthalate (DBP in the ambient. Nano-PANI is prepared using a non-template method and the films are deposited using physical coating method. Scanning electron microscopy is used to characterize the nano-PANI film. The sensor response towards DBP is tested in a sealed gas chamber. The QCM resonant frequency shift is measured due to the absorption of DBP with different concentration ranging from 0.04 to 1.2 ppm. The experiment results show that the variation of the frequency is a linear function of DBP concentration and the sensitivity up to 54 Hz/ppm could be achieved by using the researched nano-PANI on QCM. To investigate the selectivity, the potential interfering analytes such as acetone, ethanol, acetaldehyde and formaldehyde are tested. And the mechanism hypothesis of the nano-PANI sensitive to the plasticizer is analyzed.

  17. Structural synthesis of electrical engineering complex’ control system of a plant for plastic shaping of the ceramic mixture

    Directory of Open Access Journals (Sweden)

    Galitskov Stanislav

    2017-01-01

    Full Text Available Production of ceramic bricks with the required strength imposes significant restrictions on the process control of plastic shaping of the ceramic mixture in the auger extruder. It is due to several factors. Firstly, the certain nonstationarity of rheological properties of the source raw materials necessitates the automatic task-oriented changes in combinations of such values as shear rate, ceramic mixture moisture and vacuum pressure in the vacuum chamber of the extruder. To solve this problem it is necessary to maintain a coordinated control of the relevant automatic control systems of the electrical engineering complex. The second problem is the lack of technical tools to measure the values of shear rate in the pressure head of the extruder. And finally, the third factor is a necessity for monitoring and modeling of operating steps in brick production – from shaping to finished product output, that is a necessity to assess the impact of drying and firing processes on the possibility to make bricks of specified strength. The paper considers structural synthesis of the electrical engineering complex’ control system for plastic shaping of the ceramic mixture, including the problem of coordinated control: of the vacuum pump’ electrical drive, of the solenoid valve for water dosing, of the belt feeder’ electrical drives, of the mixer and the auger, as well as the use of digital observers of technological controlled coordinates and models in further phases of brick production.

  18. A Method of Heat Exchange Structure Optimization of the Cricoid Plastic Parts

    Directory of Open Access Journals (Sweden)

    Dongpo Yang

    2014-01-01

    Full Text Available This paper research on the effect of heat transfer performance of ring wall structure change of ship water heater top cricoid hood. A method of equivalent conversion is applied on simplify the structure of finned tube heat exchanger, it distinct reduce the computational grid, and improve the simulation speed and accuracy. This method can be used to calculate the ventilation and heat transfer of that compact configuration type structure in the complex component. Changing the ring wall structure can improve heat transfer performance, based on the method of equivalent transformation, a new heat transfer structure is established.

  19. Low among-provenance differences in structural and functional plasticity in response to nutrients in saplings of the circum-Mediterranean tree Arbutus unedo L.

    Science.gov (United States)

    Santiso, Xabier; Retuerto, Rubén

    2015-10-01

    The Mediterranean region is an area of special interest for conservation where the incidence of multiple drivers of global change is expected to increase. One of the factors predicted to change is soil-nutrient availability, an essential factor for plant growth. Thus, study of the effects of variation in this parameter is especially relevant in species with a circum-Mediterranean distribution, such as Arbutus unedo L., in which the different provenances grow in different habitats, which must differ in nutritional conditions. We aimed to determine the effect of provenance on plasticity, to establish whether structural and morphological traits differ in the level of plasticity and to assess how nutrients affect the photosynthetic light response. In a common garden experiment, we studied seven provenances from the circum-Mediterranean range of A. unedo and established two nutrient treatments (low and high nutrient availability). We measured physiological and structural traits in 1-year-old sapling and determined a phenotypic plasticity index (PPI) to quantify the level of plasticity, whereas the radiation effects were tested by construction and analysis of light response curves. Interestingly, provenance did not explain a significant amount of variance, but the plasticity was four times higher for the structural traits than for the physiological traits. Therefore, the plasticity to nutrient availability will not favour or prevent the expansion or contraction of the range of any of these provenances of A. unedo. Furthermore, the structural plasticity demonstrated the ability of the strawberry tree to optimize resource allocation, whereas the physiology remained stable, thus avoiding extra expenditure. The study findings also suggest that increased availability of nutrients would improve the performance of the species during the Mediterranean summer, characterized by high irradiance. These abilities will be key to the survival of saplings of the species under the future

  20. Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones.

    Science.gov (United States)

    Munivrana, Goran; Petrinović, Lidija Zekan; Kondrič, Miran

    2015-09-29

    For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire) was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster) analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A) used in the phase of preparing one's own and disabling the opponent's attack; a group of technical-tactical elements (B) used in the phase of attack and counterattack; and a group of technical-tactical elements (C) used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts' scores.

  1. Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones

    Directory of Open Access Journals (Sweden)

    Munivrana Goran

    2015-09-01

    Full Text Available For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A used in the phase of preparing one’s own and disabling the opponent’s attack; a group of technical-tactical elements (B used in the phase of attack and counterattack; and a group of technical-tactical elements (C used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts’ scores.

  2. Structured Task versus Free Play: The Influence of Social Context on Parenting Quality, Toddlers' Engagement with Parents and Play Behaviors, and Parent-Toddler Language Use

    Science.gov (United States)

    Kwon, Kyong-Ah; Bingham, Gary; Lewsader, Joellen; Jeon, Hyun-Joo; Elicker, James

    2013-01-01

    Background: Little empirical research examines relations among the quality of both mothers' and fathers' social emotional and linguistic support of toddlers across multiple parent-child interaction contexts. Objective: The current study investigated the influence of parent gender (mother vs. father) and activity setting (structured task vs. free…

  3. A viscoplastic model with plasticity for dry clay. Application to underground structures

    International Nuclear Information System (INIS)

    Tchiyep Piepi, G.

    1995-10-01

    Stiff clays are generally encountered at a great depth (more than 300 m). These materials have a relatively low water content. A lot of industrial studies justify the recent interest borne by these materials. This work deals in particular with stiff clays able to answer to stresses by elastic, plastic and viscoplastic deformations. In the first part are given the experimental study and the modelling of the stiff clays mechanical behavior. In this part, considered materials are described as well as the tests carried out. The obtained results are discussed and a viscoplastic model with rupture is elaborated. The second part deals with the elaboration of an original semi analytical solution and of an algorithm implemented in GEOMEC91. The third part shows the influence of the model on the tunnel convergence at the moment of the support laying and by consequently on the stresses of this last one. The calculations results show a strong influence of the short-term cohesion on the tunnel convergence. (O.M.)

  4. Basal tissue structure in the earliest euconodonts: Testing hypotheses of developmental plasticity in euconodont phylogeny

    Science.gov (United States)

    Dong, X.-P.; Donoghue, P.C.J.; Repetski, J.E.

    2005-01-01

    The hypothesis that conodonts are vertebrates rests solely on evidence of soft tissue anatomy. This has been corroborated by microstructural, topological and developmental evidence of homology between conodont and vertebrate hard tissues. However, these conclusions have been reached on the basis of evidence from highly derived euconodont taxa and the degree to which they are representative of plesiomorphic euconodonts remains an open question. Furthermore, the range of variation in tissue types comprising the euconodont basal body has been used to establish a hypothesis of developmental plasticity early in the phylogeny of the clade, and a model of diminishing potentiality in the evolution of development systems. The microstructural fabrics of the basal tissues of the earliest euconodonts (presumed to be the most plesiomorphic) are examined to test these two hypotheses. It is found that the range of microstructural variation observed hitherto was already apparent among plesiomorphic euconodonts. Thus, established histological data are representative of the most plesiomorphic euconodonts. However, although there is evidence of a range in microstructural fabrics, these are compatible with the dentine tissue system alone, and the degree of variation is compatible with that seen in clades of comparable diversity. ?? The Palaeontological Association.

  5. Plasticity of the Binding Site of Renin: Optimized Selection of Protein Structures for Ensemble Docking.

    Science.gov (United States)

    Strecker, Claas; Meyer, Bernd

    2018-05-02

    Protein flexibility poses a major challenge to docking of potential ligands in that the binding site can adopt different shapes. Docking algorithms usually keep the protein rigid and only allow the ligand to be treated as flexible. However, a wrong assessment of the shape of the binding pocket can prevent a ligand from adapting a correct pose. Ensemble docking is a simple yet promising method to solve this problem: Ligands are docked into multiple structures, and the results are subsequently merged. Selection of protein structures is a significant factor for this approach. In this work we perform a comprehensive and comparative study evaluating the impact of structure selection on ensemble docking. We perform ensemble docking with several crystal structures and with structures derived from molecular dynamics simulations of renin, an attractive target for antihypertensive drugs. Here, 500 ns of MD simulations revealed binding site shapes not found in any available crystal structure. We evaluate the importance of structure selection for ensemble docking by comparing binding pose prediction, ability to rank actives above nonactives (screening utility), and scoring accuracy. As a result, for ensemble definition k-means clustering appears to be better suited than hierarchical clustering with average linkage. The best performing ensemble consists of four crystal structures and is able to reproduce the native ligand poses better than any individual crystal structure. Moreover this ensemble outperforms 88% of all individual crystal structures in terms of screening utility as well as scoring accuracy. Similarly, ensembles of MD-derived structures perform on average better than 75% of any individual crystal structure in terms of scoring accuracy at all inspected ensembles sizes.

  6. Fibre Bragg Grating Sensor Signal Post-processing Algorithm: Crack Growth Monitoring in Fibre Reinforced Plastic Structures

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2016-01-01

    A novel method to assess a crack growing/damage event in fibre reinforced plastic, using conventional single mode Fibre Bragg Grating sensors embedded in the host material is presented in this article. Three different damage mechanisms that can change the sensor output, longitudinal strain εxx......, transversal stress σyy;zz, and non-uniform strain εxx(xx), were identified. These damage mechanisms were identified during the experimental testing and linked with the sensor output using a digital image correlation technique. A dedicated algorithm to extract information from the reflected spectrum...... that enables crack detection was developed. Double Cantilever Beams specimens made with glass fibre and bonded with structural adhesive, were instrumented with a Fibre Bragg Grating array embedded in the host material, and tested using an experimental fracture procedure. This method was successfully validated...

  7. Determination of structural and mechanical properties, diffractometry, and thermal analysis of chitosan and hydroxypropylmethylcellulose (HPMC films plasticized with sorbitol

    Directory of Open Access Journals (Sweden)

    Jefferson Rotta

    2011-06-01

    Full Text Available In this work, the structural, mechanical, diffractometric, and thermal parameters of chitosan-hydroxypropylmethylcellulose (HPMC films plasticized with sorbitol were studied. Solutions of HPMC (2% w/v in water and chitosan (2% w/v in 2% acetic acid solution were prepared. The concentration of sorbitol used was 10% (w/w to both polymers. This solutions were mixed at different proportions (100/0; 70/30; 50/50; 30/70, and 0/100 of chitosan and HPMC, respectively, and 20 mL was cast in Petri dishes for further analysis of dried films. The miscibility of polymers was assessed by X-ray diffraction, scanning electronic microscopy (SEM, differential scanning calorimetry (DSC, and thermal gravimetric analysis (TGA. The results obtained indicate that the films are not fully miscible at a dry state despite the weak hydrogen bonding between the polymer functional groups.

  8. Method for detecting damage in carbon-fibre reinforced plastic-steel structures based on eddy current pulsed thermography

    Science.gov (United States)

    Li, Xuan; Liu, Zhiping; Jiang, Xiaoli; Lodewijks, Gabrol

    2018-01-01

    Eddy current pulsed thermography (ECPT) is well established for non-destructive testing of electrical conductive materials, featuring the advantages of contactless, intuitive detecting and efficient heating. The concept of divergence characterization of the damage rate of carbon fibre-reinforced plastic (CFRP)-steel structures can be extended to ECPT thermal pattern characterization. It was found in this study that the use of ECPT technology on CFRP-steel structures generated a sizeable amount of valuable information for comprehensive material diagnostics. The relationship between divergence and transient thermal patterns can be identified and analysed by deploying mathematical models to analyse the information about fibre texture-like orientations, gaps and undulations in these multi-layered materials. The developed algorithm enabled the removal of information about fibre texture and the extraction of damage features. The model of the CFRP-glue-steel structures with damage was established using COMSOL Multiphysics® software, and quantitative non-destructive damage evaluation from the ECPT image areas was derived. The results of this proposed method illustrate that damaged areas are highly affected by available information about fibre texture. This proposed work can be applied for detection of impact induced damage and quantitative evaluation of CFRP structures.

  9. Plastic deformation of single crystals of WSi2 with the C11b structure

    International Nuclear Information System (INIS)

    Ito, K.; Yano, T.; Nakamoto, T.; Inui, H.; Yamaguchi, M.

    1999-01-01

    The deformation behavior of single crystals of WSi 2 has been investigated as a function of crystal orientation in the temperature range from room temperature to 1500 C in compression. Single crystals of WSi 2 can be deformed only at high temperatures above 1100 C, in contrast to MoSi 2 in which plastic flow is possible even at room temperature. Four slip systems, {110} left-angle 111 right-angle, {011} left-angle 100 right-angle, {023} left-angle 100 right-angle and (001)left-angle 100 right-angle, are identified. While the former three slip systems are operative also in MoSi 2 , the (001)left-angle 100 right-angle slip is only operative in WSi 2 . The (001)left-angle 100 right-angle slip in WSi 2 is the alternative to {013} left-angle 331 right-angle slip in MoSi 2 since they are operative in the same orientation range. Slip on {110} left-angle 331 right-angle is hardly observed in WSi 2 . The values of critical resolved shear stress (CRSS) for the commonly observed slip systems are much higher in WSi 2 than in MoSi 2 with the largest difference for {110} left-angle 111 right-angle slip. The higher CRSS values in WSi 2 are not only due to the intrinsic difference in the deformation behavior but also due to the existence of numerous grown-in stacking faults on (001)

  10. Neural plasticity expressed in central auditory structures with and without tinnitus

    Directory of Open Access Journals (Sweden)

    Larry E Roberts

    2012-05-01

    Full Text Available Sensory training therapies for tinnitus are based on the assumption that, notwithstanding neural changes related to tinnitus, auditory training can alter the response properties of neurons in auditory pathways. To address this question, we investigated whether brain changes induced by sensory training in tinnitus sufferers and measured by EEG are similar to those induced in age and hearing loss matched individuals without tinnitus trained on the same auditory task. Auditory training was given using a 5 kHz 40-Hz amplitude-modulated sound that was in the tinnitus frequency region of the tinnitus subjects and enabled extraction of the 40-Hz auditory steady-state response (ASSR and P2 transient response known to localize to primary and nonprimary auditory cortex, respectively. P2 amplitude increased with training equally in participants with tinnitus and in control subjects, suggesting normal remodeling of nonprimary auditory regions in tinnitus. However, training-induced changes in the ASSR differed between the tinnitus and control groups. In controls ASSR phase advanced toward the stimulus waveform by about ten degrees over training, in agreement with previous results obtained in young normal hearing individuals. However, ASSR phase did not change significantly with training in the tinnitus group, although some participants showed phase shifts resembling controls. On the other hand, ASSR amplitude increased with training in the tinnitus group, whereas in controls this response (which is difficult to remodel in young normal hearing subjects did not change with training. These results suggest that neural changes related to tinnitus altered how neural plasticity was expressed in the region of primary but not nonprimary auditory cortex. Auditory training did not reduce tinnitus loudness although a small effect on the tinnitus spectrum was detected.

  11. Beneficial effects of benzodiazepine diazepam on chronic stress-induced impairment of hippocampal structural plasticity and depression-like behavior in mice.

    Science.gov (United States)

    Zhao, Yunan; Wang, Zhongli; Dai, Jianguo; Chen, Lin; Huang, Yufang; Zhan, Zhen

    2012-03-17

    Whether benzodiazepines (BZDs) have beneficial effects on the progress of chronic stress-induced impairment of hippocampal structural plasticity and major depression is uncertain. The present study designed four preclinical experiments to determine the effects of BZDs using chronic unpredictable stress model. In Experiment 1, several time course studies on behavior and hippocampus response to stress were conducted using the forced swim and tail suspension tests (FST and TST) as well as hippocampal structural plasticity markers. Chronic stress induced depression-like behavior in the FST and TST as well as decreased hippocampal structural plasticity that returned to normal within 3 wk. In Experiment 2, mice received p.o. administration of three diazepam dosages prior to each variate stress session for 4 wk. This treatment significantly antagonized the elevation of stress-induced corticosterone levels. Only low- (0.5mg/kg) and medium-dose (1mg/kg) diazepam blocked the detrimental effects of chronic stress. In Experiment 3, after 7 wk of stress sessions, daily p.o. diazepam administration during 1 wk recovery phase dose-dependently accelerated the recovery of stressed mice. In Experiment 4, 1 wk diazepam administration to control mice enhanced significantly hippocampal structural plasticity and induced an antidepressant-like behavioral effect, whereas 4 wk diazepam administration produced opposite effects. Hence, diazepam can slow the progress of chronic stress-induced detrimental consequences by normalizing glucocorticoid hormones. Considering the adverse effect of long-term diazepam administration on hippocampal plasticity, the preventive effects of diazepam may depend on the proper dose. Short-term diazepam treatment enhances hippocampal structural plasticity and is beneficial to recovery following chronic stress. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Optimisation by plastic deformation of structural and mechanical uranium alloys properties

    International Nuclear Information System (INIS)

    Prunier, Claude.

    1981-08-01

    Structural and mechanical properties evolution of rich and poor uranium alloys are investigated. Good usual properties are obtained with few metallic additions with a limited effect giving a fine and isotrope grain structure. Amelioration is observed with heat treatment from β and γ phases high temperature range. However, dynamic recrystallisation, related to hot working, is the better phenomena to maximize the usual mechanical and structural properties. So high temperature behaviour of rich and poor uranium alloys in α, β and γ crystalline structure is studied: - dynamic recrystallisation phenomena begins only in α, and β phases high temperature range; - high strength and brittle β phase shows a very large ductility above 700 deg C. Recrystallisation is a thermal actived phenomena localised at grain boundary, dependant with alloys concentration and crystalline structure. β phase activation energy and deformation rate for dynamic recrystallisation beginning are most important, than α and γ phases in relation with quadratic structure complexity. Both temperature and deformation rate are the main dynamic recrystallisation factors. Optimal usual mechanical and structural properties obtained by hot working (forging, milling) are sensible to hydrogen embrittlement [fr

  13. Mechanical and structural behaviour of uranium α, β, γ phases during plastic deformation

    International Nuclear Information System (INIS)

    Prunier, C.; Collot, C.

    1981-06-01

    High temperature behaviour of rich and poor uranium alloys in α, β and γ crystalline structures is studied: dynamic recrystallization phenomena begins only in α and β phases high temperature range, high strength and brittle β phase shows a very large ductility above 700 0 C. Dynamic recrystallization in γ phase rich alloys is observed only if large energy is available. Recrystallization is a thermal actived phenomena localised at grain boundary, dependant with alloy concentration and crystalline structure. β phase activation energy and deformation rate for dynamic recrystallization beginning are the most important in relation with structure complexity; both temperature and rate deformation are dynamic recrystallization factors [fr

  14. Strain gradient crystal plasticity: A continuum mechanics approach to modeling micro-structural evolution

    DEFF Research Database (Denmark)

    El-Naaman, Salim Abdallah; Nielsen, Kim Lau; Niordson, Christian Frithiof

    2015-01-01

    In agreement with dislocation theory, recent experiments show, both quantitatively and qualitatively, how geometrically necessary dislocations (GNDs) distribute in dislocation wall and cell structures. Hence, GND density fields are highly localized with large gradients and discontinuities occurring...

  15. Clarification on shear transformation zone size and its correlation with plasticity for Zr-based bulk metallic glass in different structural states

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.Q.; Huang, L. [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Huang, P., E-mail: huangping@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Xu, K.W. [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, F., E-mail: wangfei@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures Xi' an Jiaotong University, Xi' an 710049 (China); Lu, T.J. [State Key Laboratory for Strength and Vibration of Mechanical Structures Xi' an Jiaotong University, Xi' an 710049 (China); MOE Key Laboratory for Multifunctional Materials and Structures Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-11-20

    To clarify the real size of shear transformation zone (STZ) and its correlation with the plasticity of metallic glass, STZ sizes of a Zr-based bulk metallic glass (BMG) in three different structural states (as-cast, annealed and confining annealed) were examined using both rate-change and statistical methods upon nanoindentation. STZ sizes (less than 24 atoms) obtained by the statistical method approached the real STZ size of very few atoms, and showed no correlation with BMG plasticity. In sharp contrast, STZ sizes (hundreds of atoms) obtained by the rate-change method not only were much larger than the real STZ size but also exhibited a positive correlation with BMG plasticity. These discrepancies were discussed in terms of the structural evolution of BMGs upon nanoindentation.

  16. Intensely irradiated steel components: Plastic and fracture properties, and a new concept of structural design criteria for assuring the structural integrity

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kazuhiko, E-mail: suzuki.kazuhiko@jaea.go.j [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Jitsukawa, Shiro; Okubo, Nariaki [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Takada, Fumiki [Japan Atomic Energy Agency, Department of JMTR Operation, Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki-ken 311-1393 (Japan)

    2010-06-15

    In order to develop a systematic and reasonable concept assuring the structural integrity of components under intense neutron irradiation, two basic tensile properties, true stress-true strain (TS-TS) curves and fracture strain, were investigated on an austenitic stainless steel and martensitic steel. Application of Swift equation is confirmed to a large plastic strain range of TS-TS curves. Fracture strain epsilon{sub f} data were well correlated as epsilon{sub f} + epsilon{sub 0} = const. where epsilon{sub 0} is the pre-strain representing the irradiation hardening. Based on those formulations and available experimental information, several critical issues to be dealt with in developing the concept were identified possible reduction in ductility, significant change in mechanical properties, remarkable cyclic softening and other unique cyclic properties observed during a high-cycle fatigue testing, and the redundancy of the plastic collapse concept to bending. Existing structural codes are all based on the assumption that there will be no significant changes in mechanical properties during operation, and of high ductility. Therefore, a new concept for assuring structural integrity is required for application not only to components with high ductility but also components with reduced ductility. First, potential failure modes were identified, and a new and systematic concept was proposed for preventing these modes of failure, introducing a new concept of categorizing the loadings by stability of deformation process to fracture (as type F and M loadings). Based on the basic concept, a detailed concept of how to protect against ductile fracture was given, and loading type-dependent limiting parameters were set. Finally, application of the detailed concept was presented, especially on determination of loading type (in numerical approach, the formulation of TS-TS curves and fracture strain derived above are needed), and on how to determine the limiting parameters as

  17. Intensely irradiated steel components: Plastic and fracture properties, and a new concept of structural design criteria for assuring the structural integrity

    International Nuclear Information System (INIS)

    Suzuki, Kazuhiko; Jitsukawa, Shiro; Okubo, Nariaki; Takada, Fumiki

    2010-01-01

    In order to develop a systematic and reasonable concept assuring the structural integrity of components under intense neutron irradiation, two basic tensile properties, true stress-true strain (TS-TS) curves and fracture strain, were investigated on an austenitic stainless steel and martensitic steel. Application of Swift equation is confirmed to a large plastic strain range of TS-TS curves. Fracture strain ε f data were well correlated as ε f + ε 0 = const. where ε 0 is the pre-strain representing the irradiation hardening. Based on those formulations and available experimental information, several critical issues to be dealt with in developing the concept were identified possible reduction in ductility, significant change in mechanical properties, remarkable cyclic softening and other unique cyclic properties observed during a high-cycle fatigue testing, and the redundancy of the plastic collapse concept to bending. Existing structural codes are all based on the assumption that there will be no significant changes in mechanical properties during operation, and of high ductility. Therefore, a new concept for assuring structural integrity is required for application not only to components with high ductility but also components with reduced ductility. First, potential failure modes were identified, and a new and systematic concept was proposed for preventing these modes of failure, introducing a new concept of categorizing the loadings by stability of deformation process to fracture (as type F and M loadings). Based on the basic concept, a detailed concept of how to protect against ductile fracture was given, and loading type-dependent limiting parameters were set. Finally, application of the detailed concept was presented, especially on determination of loading type (in numerical approach, the formulation of TS-TS curves and fracture strain derived above are needed), and on how to determine the limiting parameters as allowable limits. Experiments were done to

  18. Dislocation structure evolution in 304L stainless steel and weld joint during cyclic plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hao; Jing, Hongyang; Zhao, Lei; Han, Yongdian; Lv, Xiaoqing [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300072 (China); Xu, Lianyong, E-mail: xulianyong@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300072 (China)

    2017-04-06

    Dislocation structures and their evolution of 304L stainless steel and weld metal made with ER308L stainless steel welding wire subjected to uniaxial symmetric strain-controlled loading and stress-controlled ratcheting loading were observed by transmission electron microscopy (TEM). The correlation between the cyclic response and the dislocation structure has been studied. The experiment results show that the cyclic behaviour of base metal and weld metal are different. The cyclic behaviour of the base metal consists of primary hardening, slight softening and secondary hardening, while the weld metal shows a short hardening within several cycles followed by the cyclic softening behaviour. The microscopic observations indicate that in base metal, the dislocation structures evolve from low density patterns to those with higher dislocation density during both strain cycling and ratcheting deformation. However, the dislocation structures of weld metal change oppositely form initial complicated structures to simple patterns and the dislocation density gradually decrease. The dislocation evolution presented during the strain cycling and ratcheting deformation is summarized, which can qualitatively explain the cyclic behaviour and the uniaxial ratcheting behaviour of two materials. Moreover, the dislocation evolution in the two types of tests is compared, which shows that the mean stress has an effect on the rate of dislocation evolution during the cyclic loading.

  19. Determination of dynamic characteristics of multi-layer carbon plastic structures of high-resolution scanner

    Directory of Open Access Journals (Sweden)

    В. Н. Маслей

    2017-10-01

    Full Text Available The comparative analysis results for the numerical determination of the dynamic characteristics of multi-layer carbon-fiber plates of the space vehicle scanner design by various types of finite element approximation of the physico-mechanical properties of the composite material are presented. Using the topological structure of the construction of reinforcing layers material in the plate package plane, experimental data for the elastic and mass characteristics of homogeneous carbon-fiber fibers, equivalent structural and orthotropic stiffness and elastic characteristics of the material of composite plates are determined.

  20. Effects of growth curve plasticity on size-structured population dynamics

    DEFF Research Database (Denmark)

    Zhang, Lai; Lin, Zhigui; Pedersen, Michael

    2011-01-01

    The physiological-structured population models assume that a fixed fraction of energy intake is utilized for individual growth and maintenance while the remaining for adult fertility. The assumption results in two concerns: energy loss for juveniles and a reproduction dilemma for adults. The dile...

  1. The Structural Plasticity of White Matter Networks Following Anterior Temporal Lobe Resection

    Science.gov (United States)

    Yogarajah, Mahinda; Focke, Niels K.; Bonelli, Silvia B.; Thompson, Pamela; Vollmar, Christian; McEvoy, Andrew W.; Alexander, Daniel C.; Symms, Mark R.; Koepp, Matthias J.; Duncan, John S.

    2010-01-01

    Anterior temporal lobe resection is an effective treatment for refractory temporal lobe epilepsy. The structural consequences of such surgery in the white matter, and how these relate to language function after surgery remain unknown. We carried out a longitudinal study with diffusion tensor imaging in 26 left and 20 right temporal lobe epilepsy…

  2. Neuroserpin and brain-derived neurotrophic factor in neuroendocrine and neuronal plasticity. Functional studies in (transgenic) Xenopus intermediate pituitary cells

    NARCIS (Netherlands)

    Rotteveel-de Groot, D.M. de

    2007-01-01

    The molecular mechanisms underlying neuronal plasticity, i.e. the capacity of the brain to continuously adapt its structural organization to new situations, remain largely unknown. In this thesis, we explored functional aspects of two proteins that presumably play a role in neuronal plasticity,

  3. Cortical and Subcortical Structural Plasticity Associated with the Glioma Volumes in Patients with Cerebral Gliomas Revealed by Surface-Based Morphometry

    Directory of Open Access Journals (Sweden)

    Jinping Xu

    2017-06-01

    Full Text Available Postlesional plasticity has been identified in patients with cerebral gliomas by inducing a large functional reshaping of brain networks. Although numerous non-invasive functional neuroimaging methods have extensively investigated the mechanisms of this functional redistribution in patients with cerebral gliomas, little effort has been made to investigate the structural plasticity of cortical and subcortical structures associated with the glioma volume. In this study, we aimed to investigate whether the contralateral cortical and subcortical structures are able to actively reorganize by themselves in these patients. The compensation mechanism following contralateral cortical and subcortical structural plasticity is considered. We adopted the surface-based morphometry to investigate the difference of cortical and subcortical gray matter (GM volumes in a cohort of 14 healthy controls and 13 patients with left-hemisphere cerebral gliomas [including 1 patients with World Health Organization (WHO I, 8 WHO II, and 4 WHO III]. The glioma volume ranges from 5.1633 to 208.165 cm2. Compared to healthy controls, we found significantly increased GM volume of the right cuneus and the left thalamus, as well as a trend toward enlargement in the right globus pallidus in patients with cerebral gliomas. Moreover, the GM volumes of these regions were positively correlated with the glioma volumes of the patients. These results provide evidence of cortical and subcortical enlargement, suggesting the usefulness of surface-based morphometry to investigate the structural plasticity. Moreover, the structural plasticity might be acted as the compensation mechanism to better fulfill its functions in patients with cerebral gliomas as the gliomas get larger.

  4. Evaluation of solid waste and plastic clay mixtures for structural ceramic use; Avaliacao de misturas de residuo solido com argila plastica para aplicacao em ceramica vermelha

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Neli Iloni Warpechowski da [Fundacao de Ciencia e Tecnologia (CIENTEC), Porto Alegre, RS (Brazil); Belo, Pedro [Ceramics Representacoes Comerciais Ltda, Porto Alegre, RS (Brazil)

    1996-07-01

    This work aims to verify the behaviour of the organic solid waste added by 10%, 15% and 20% in mixture in a plastic clay. It intends to emphasize the influence of the waste in the mixture. Technology tests have been carried out in the clay and mixtures to obtain possible uses in the structural ceramics. (author) 1 ref., 4 figs., 2 tabs.

  5. Playful Membership

    DEFF Research Database (Denmark)

    Åkerstrøm Andersen, Niels; Pors, Justine Grønbæk

    2014-01-01

    This article studies the implications of current attempts by organizations to adapt to a world of constant change by introducing the notion of playful organizational membership. To this end we conduct a brief semantic history of organizational play and argue that when organizations play, employees...... are expected to engage in playful exploration of alternative selves. Drawing on Niklas Luhmann's theory of time and decision-making and Gregory Bateson's theory of play, the article analyses three empirical examples of how games play with conceptions of time. We explore how games represent an organizational...

  6. Elasto-plastic response of multi-story shear wall structures

    International Nuclear Information System (INIS)

    Mizutani, M.; Yamazaki, F.

    1987-01-01

    A Monte Carlo simulation study is carried out. The relationship between the elastoplastic and linear response for multi-DOF systems is developed based on the results of the simulation study. Several 6-story shear wall structures are considered as structural models which represent typical nuclear power plant buildings. A bilinear force-displacement relationship is assumed for each story. A number of artificial earthquakes based on the Kanai-Tajimi power spectrum and trapezoidal envelope function are used as the input ground motion. The least square method is introduced for the purpose of evaluating the median relationship between the ductility factor and linear response from the simulated data and also evaluating the deviation from this median relationship. This relationship derived for the 6-story buildings is compared with the currently used energy absorption factor and the simulation results for Zion auxiliary building model. (orig./HP)

  7. Structural Plasticity of PAM Recognition by Engineered Variants of the RNA-Guided Endonuclease Cas9.

    Science.gov (United States)

    Anders, Carolin; Bargsten, Katja; Jinek, Martin

    2016-03-17

    The RNA-guided endonuclease Cas9 from Streptococcus pyogenes (SpCas9) forms the core of a powerful genome editing technology. DNA cleavage by SpCas9 is dependent on the presence of a 5'-NGG-3' protospacer adjacent motif (PAM) in the target DNA, restricting the choice of targetable sequences. To address this limitation, artificial SpCas9 variants with altered PAM specificities have recently been developed. Here we report crystal structures of the VQR, EQR, and VRER SpCas9 variants bound to target DNAs containing their preferred PAM sequences. The structures reveal that the non-canonical PAMs are recognized by an induced fit mechanism. Besides mediating sequence-specific base recognition, the amino acid substitutions introduced in the SpCas9 variants facilitate conformational remodeling of the PAM region of the bound DNA. Guided by the structural data, we engineered a SpCas9 variant that specifically recognizes NAAG PAMs. Taken together, these studies inform further development of Cas9-based genome editing tools. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Play, Playfulness, Creativity and Innovation

    Directory of Open Access Journals (Sweden)

    Patrick Bateson

    2014-05-01

    Full Text Available Play, as defined by biologists and psychologists, is probably heterogeneous. On the other hand, playfulness may be a unitary motivational state. Playful play as opposed to activities that merge into aggression is characterized by positive mood, intrinsic motivation, occurring in a protected context and easily disrupted by stress. Playful play is a good measure of positive welfare. It can occupy a substantial part of the waking-life of a young mammal or bird. Numerous functions for play have been proposed and they are by no means mutually exclusive, but some evidence indicates that those individual animals that play most are most likely to survive and reproduce. The link of playful play to creativity and hence to innovation in humans is strong. Considerable evidence suggests that coming up with new ideas requires a different mindset from usefully implementing a new idea.

  9. Buckling Modes of Structural Elements of Off-Axis Fiber-Reinforced Plastics

    Science.gov (United States)

    Paimushin, V. N.; Polyakova, N. V.; Kholmogorov, S. A.; Shishov, M. A.

    2018-05-01

    The structures of two types of unidirectional fiber-reinforced composites — with an ELUR-P carbon fiber tape, an XT-118 cold-cure binder with an HSE 180 REM prepreg, and a hot-cure binder — were investigated. The diameters of fibers and fiber bundles (threads) of both the types of composites were measured, and their mutual arrangement was examined both in the semifinished products (in the uncured state) and in the finished composites. The defects characteristic of both the types of binder and manufacturing technique were detected in the cured composites. Based on an analysis of the results obtained, linearized problems on the internal multiscale buckling modes of an individual fiber (with and without account of its interaction with the surrounding matrix) or of a fiber bundle are formulated. In the initial atate, these structural elements of the fibrous composites are in a subcritical (unperturbed) state under the action of shear stresses and tension (compression) in the transverse direction. Such an initial stress state is formed in them in tension and compression tests on flat specimens made of off-axis-reinforced composites with straight fibers. To formulate the problems, the equations derived earlier from a consistent variant of geometrically nonlinear equations of elasticity theory by reducing them to the one-dimensional equations of the theory of straight rods on the basis of a refined Timoshenko shear model with account of tensile-compressive strains in the transverse direction are used. It is shown that, in loading test specimens, a continuous rearrangement of composite structure can occur due to the realization and continuous change of internal buckling modes as the wave-formation parameter varies continuously, which apparently explain the decrease revealed in the tangential shear modulus of the fibrous composites with increasing shear strains.

  10. Spatial organization of plastic deformation in single crystals with different structure of slip dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Kunitsyna, T. S.; Teplyakova, L. A., E-mail: lat168@mail.ru; Koneva, N. A. [Tomsk State University of Architecture and Building, Tomsk, 634003 (Russian Federation); Poltaranin, M. A. [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    It is established that different structure of slip dislocation at the end of the linear hardening stage results in different distribution of dislocation charges in the volume of a single crystal. In the alloy with a near atomic order the slip of single dislocations leads to formation of planar structures—layers with the excess density of dislocations. In the alloy with long-range atomic order the slip of superdislocations brings the formation of the system of parallel rod-like charged dislocation linking.

  11. Texture and structure contribution to low-temperature plasticity enhancement of Mg-Al-Zn-Mn Alloy MA2-1hp after ECAP and annealing

    Science.gov (United States)

    Serebryany, V. N.; D'yakonov, G. S.; Kopylov, V. I.; Salishchev, G. A.; Dobatkin, S. V.

    2013-05-01

    Equal channel angular pressing (ECAP) in magnesium alloys due to severe plastic shear deformations provides both grain refinement and the slope of the initial basal texture at 40°-50° to the pressing direction. These changes in microstructure and texture contribute to the improvement of low-temperature plasticity of the alloys. Quantitative texture X-ray diffraction analysis and diffraction of backscattered electrons are used to study the main textural and structural factors responsible for enhanced low-temperature plasticity based on the example of magnesium alloy MA2-1hp of the Mg-Al-Zn-Mn system. The possible mechanisms of deformation that lead to this positive effect are discussed.

  12. Born with an ear for dialects? Structural plasticity in the expert phonetician brain.

    Science.gov (United States)

    Golestani, Narly; Price, Cathy J; Scott, Sophie K

    2011-03-16

    Are experts born with particular predispositions, or are they made through experience? We examined brain structure in expert phoneticians, individuals who are highly trained to analyze and transcribe speech. We found a positive correlation between the size of left pars opercularis and years of phonetic transcription training experience, illustrating how learning may affect brain structure. Phoneticians were also more likely to have multiple or split left transverse gyri in the auditory cortex than nonexpert controls, and the amount of phonetic transcription training did not predict auditory cortex morphology. The transverse gyri are thought to be established in utero; our results thus suggest that this gross morphological difference may have existed before the onset of phonetic training, and that its presence confers an advantage of sufficient magnitude to affect career choices. These results suggest complementary influences of domain-specific predispositions and experience-dependent brain malleability, influences that likely interact in determining not only how experience shapes the human brain but also why some individuals become engaged by certain fields of expertise.

  13. The CEASEMT system (Calculation and Analysis of Structures in Mechanics and Thermics). Program TRICO. Analysis of tridimensionnal structures made of shells and beams. Statics - Dynamics - Elasticity - Plasticity - Collapse - Large displacements

    International Nuclear Information System (INIS)

    Hoffmann, Alain; Jeanpierre, Francoise.

    1976-01-01

    The TRICO subroutine of the CEASEMT system is especially intended for elastic or plastic computation of structures made of thin shells and beams. TRICO involves the finite element method for shells and beams, and is also suitable for a dynamic structural analysis: eigenmode and eigenfrequency analysis, and analysis of the response to various sinusoidal excitations, or time dependent elastic and plastic loading. Structures may have various shapes composed of a number of materials. Data are distributed between different optional commands having a precise physical sense, corresponding to a sequential program. A dynamic memory control provides the adaptation of the size of the program to that of the problem to be solved [fr

  14. Plastics: Friend or foe?

    Directory of Open Access Journals (Sweden)

    O P Gupta

    2018-01-01

    Full Text Available Plastics has been playing a very significant role in our life. Being light weight, inexpensive and heving good insulating properties it is being used in all aspects of life, from clothes to contact lenses and from mobile phones to automobiles as well as in medical equipments, However it is not biodegradable, and while degrading to fragments it gets converted in to microplastics and nanoplastics The plastic waste is being recognized as an environmental hazard, since these micr- and nanoplastics find way from landfills to water and foods, It is said that we are not only using, but we are eating, drinking and even braething the plastics. These microplastics in body release certain hazardous chemicals and found to be disrupting functions of certain endocrine organs. Whether the rising prevalence of Diabetes, thyroid disorders or infirtility etc., are realated to the plastics?

  15. Change in emotional self-concept following socio-cognitive training relates to structural plasticity of the prefrontal cortex.

    Science.gov (United States)

    Lumma, Anna-Lena; Valk, Sofie L; Böckler, Anne; Vrtička, Pascal; Singer, Tania

    2018-04-01

    Self-referential processing is a key component of the emotional self-concept. Previous studies have shown that emotional self-referential processing is related to structure and function of cortical midline areas such as medial prefrontal cortex (mPFC), and that it can be altered on a behavioral level by specific mental training practices. However, it remains unknown how behavioral training-related change in emotional self-concept content relates to structural plasticity. To address this issue, we examined the relationship between training-induced change in participant's emotional self-concept measured through emotional word use in the Twenty Statement Test and change in cortical thickness in the context of a large-scale longitudinal mental training study called the ReSource Project . Based on prior behavioral findings showing increased emotional word use particularly after socio-cognitive training targeting perspective-taking capacities, this study extended these results by revealing that individual differences in the degree to which participants changed their emotional self-concept after training was positively related to cortical thickness change in right mPFC extending to dorsolateral PFC (dlPFC). Furthermore, increased self-related negative emotional word use after training was positively associated with cortical thickness change in left pars orbitalis and bilateral dlPFC. Our findings reveal training-related structural brain change in regions known to be involved in self-referential processing and cognitive control, and could indicate a relationship between restructuring of the emotional self-concept content as well as reappraisal of negative aspects and cortical thickness change. As such, our findings can guide the development of psychological interventions targeted to alter specific facets of the self-concept.

  16. Play Therapy

    Science.gov (United States)

    Lawver, Timothy; Blankenship, Kelly

    2008-01-01

    Play therapy is a treatment modality in which the therapist engages in play with the child. Its use has been documented in a variety of settings and with a variety of diagnoses. Treating within the context of play brings the therapist and the therapy to the level of the child. By way of an introduction to this approach, a case is presented of a six-year-old boy with oppositional defiant disorder. The presentation focuses on the events and interactions of a typical session with an established patient. The primary issues of the session are aggression, self worth, and self efficacy. These themes manifest themselves through the content of the child’s play and narration of his actions. The therapist then reflects these back to the child while gently encouraging the child toward more positive play. Though the example is one of nondirective play therapy, a wide range of variation exists under the heading of play therapy. PMID:19724720

  17. Plasticity characteristic obtained by indentation

    International Nuclear Information System (INIS)

    Mil'man, Yu.V.; Chugunova, S.I.; Goncharova, I.V.

    2011-01-01

    Methods for determination plasticity characteristic δH in the measurement of hardness and nanohardness are considered. Parameter δH characterizes the plasticity of a material by the part of plastic deformation in the total elastic-plastic deformation. The value of δH is defined for metals with different types of crystal lattice, covalent and partially covalent crystals, intermetallics, metallic glasses and quasicrystals. It is discussed the dependence of the plasticity characteristic δH on structural factors and temperature. Parameter δH allows to analyze and compare the plasticity of materials which are brittle at standard mechanical tests. The combination of hardness H, as the strength characteristic, and the plasticity characteristic δH makes possible the better characterization of mechanical behavior of materials than only the hardness H. The examples of plasticity characteristic δH application are represented.

  18. More fair play in an ultimatum game after resettlement in Zimbabwe: a field experiment and a structural model.

    Science.gov (United States)

    Kohler, Stefan

    2013-01-01

    Zimbabwean villagers of distinct background have resettled in government-organized land reforms for more than three decades. Against this backdrop, I assess the level of social cohesion in some of the newly established communities by estimating the average preferences for fairness in a structural model of bounded rationality. The estimations are based on behavioral data from an ultimatum game field experiment played by 234 randomly selected households in 6 traditional and 14 resettled villages almost two decades after resettlement. Equal or higher degrees of fairness are estimated in all resettlement schemes. In one, or arguably two, out of three distinct resettlement schemes studied, the resettled villagers exhibit significantly higher degrees of fairness (p ≤ 0.11) and rationality (p ≤ 0.04) than those who live in traditional villages. Overall, villagers appear similarly rational, but the attitude toward fairness is significantly stronger in resettled communities (p ≤ 0.01). These findings are consistent with the idea of an increased need for cooperation required in recommencement.

  19. ANALYSIS OF STRUCTURAL PLASTICITY IN THE HONEY BEE BRAIN USING THE CAVALIERI ESTIMATOR OF VOLUME AND THE DISECTOR METHOD

    Directory of Open Access Journals (Sweden)

    Sheena M Brown

    2011-05-01

    Full Text Available The antennal lobe of the worker honey bee has been used as a model system to address the origins of structural plasticity in the central nervous system. A combination of light and electron microscopy was used to determine total synapse number within an easily identifiable sub-unit of the antennal lobe neuropil, the T4-2(1 glomerulus. The Cavalieri method was applied at the light microscope level to determine a reference volume (Vref of this glomerulus. Using transmission electron microscopy, the physical disector was used to determine synaptic density (Nv within the T4-2(1 glomerulus. An estimate of the total synapse number N(syn was determined by; N(syn = V(ref Nv. Newly emerged, 4-day old,10-day old and forager-aged bees were analysed. Results showed that despite a significant increase in T4-2(1 volume with age, the total number of synapses in this glomerulus did not show a corresponding increase. Disturbingly, it is possible that huge variances within age groups, due to one or two outlying data points, could be masking the true trend of synapse number. This variance, the heterogeneous distribution of synapses within this glomerulus and the problems associated with reproducibility of synapse counts are discussed.

  20. Masticatory loading, function, and plasticity: a microanatomical analysis of mammalian circumorbital soft-tissue structures.

    Science.gov (United States)

    Jasarević, Eldin; Ning, Jie; Daniel, Ashley N; Menegaz, Rachel A; Johnson, Jeffrey J; Stack, M Sharon; Ravosa, Matthew J

    2010-04-01

    In contrast to experimental evidence regarding the postorbital bar, postorbital septum, and browridge, there is exceedingly little evidence regarding the load-bearing nature of soft-tissue structures of the mammalian circumorbital region. This hinders our understanding of pronounced transformations during primate origins, in which euprimates evolved a postorbital bar from an ancestor with the primitive mammalian condition where only soft tissues spanned the lateral orbital margin between frontal bone and zygomatic arch. To address this significant gap, we investigated the postorbital microanatomy of rabbits subjected to long-term variation in diet-induced masticatory stresses. Rabbits exhibit a masticatory complex and feeding behaviors similar to primates, yet retain a more primitive mammalian circumorbital region. Three cohorts were obtained as weanlings and raised on different diets until adult. Following euthanasia, postorbital soft tissues were dissected away, fixed, and decalcified. These soft tissues were divided into inferior, intermediate, and superior units and then dehydrated, embedded, and sectioned. H&E staining was used to characterize overall architecture. Collagen orientation and complexity were evaluated via picrosirius-red staining. Safranin-O identified proteoglycan content with additional immunostaining performed to assess Type-II collagen expression. Surprisingly, the ligament along the lateral orbital wall was composed of elastic fibrocartilage. A more degraded organization of collagen fibers in this postorbital fibrocartilage is correlated with increased masticatory forces due to a more fracture-resistant diet. Furthermore, the lack of marked changes in the extracellular composition of the lateral orbital wall related to tissue viscoelasticity suggests it is unlikely that long-term exposure to elevated masticatory stresses underlies the development of a bony postorbital bar. (c) 2010 Wiley-Liss, Inc.

  1. Structural and functional plasticity of the luteinizing hormone/choriogonadotrophin receptor.

    Science.gov (United States)

    Troppmann, Britta; Kleinau, Gunnar; Krause, Gerd; Gromoll, Jörg

    2013-01-01

    BACKGROUND In recent years it became evident that several types of the luteinizing hormone/choriogonadotrophin receptor (LHCGR) exist. In addition to the classical receptor type known in rodents, an LHCGR type containing an additional exon is present in primates and humans. This specific exon 6A introduces a hitherto unknown regulatory pathway of the LHCGR at the transcriptional level which can lead to the expression of an alternative protein covering the extracellular part only. Furthermore, an LHCGR type lacking exon 10 at the mRNA and protein levels has been described in the New World primate lineage, giving rise to an additional receptor type in which amino acids of the extracellular hinge region connecting the leucine-rich repeat domain and transmembrane domain are missing. METHODS Topic-related information was retrieved by systematic searches using Medline/PubMed. Structural homology models were retrieved from a glycoprotein hormone receptors web application and from recent publications. RESULTS In a novel approach, we combine functional aspects with three-dimensional properties of the LHCGR and the different receptor types to deduce causative relationships between these two parameters. On this basis, the physiological impact and patho-physiological consequences of the different LHCGR types are inferred. CONCLUSIONS The complex system of different LHCGR types and two corresponding hormones (LH and CG) represents a major challenge for future studies on selective hormone binding, signal transduction and receptor regulation. The presence of these naturally occurring LHCGR types requires re-examining of our present view on receptor function, experimental set-ups and data interpretation, but also offers new clinical approaches to interfere with LH/CG action in humans.

  2. Rheological and structural characterisation of film-forming solutions and biodegradable edible film made from kefiran as affected by various plasticizer types.

    Science.gov (United States)

    Ghasemlou, Mehran; Khodaiyan, Faramarz; Oromiehie, Abdulrasoul

    2011-11-01

    The rheological properties of kefiran film-forming solutions, as well as the structural characterisation of the resulting films, were investigated as a function of various plasticizer types. The behaviours of the storage (G') and loss (G″) moduli as a function of frequency were typical of gel-like material, with the G' higher than the G″. Kefiran-based films, which may find application as edible films, were prepared by a casting and solvent-evaporation method. Possible interaction between the adjacent chains in the kefiran polymer and various plasticizers was proven by Fourier-transform infrared spectroscopy (FT-IR). The crystallinity of plasticized kefiran film was also analysed using X-ray diffraction (XRD); this revealed an amorphous-crystalline structure. These results were explained by the film's microstructure, which was analysed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The present study has helped determine possible interactions of kefiran, plasticizer and water molecules in determining film properties. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Playful Literacy

    DEFF Research Database (Denmark)

    Froes, Isabel

    these practices, which compose the taxonomy of tablet play. My contribution lies in identifying and proposing a series of theoretical concepts that complement recent theories related to play and digital literacy studies. The data collected through observations informed some noteworthy aspects, including how...... with tablets’ physical and digital affordances shape children’s digital play. This thesis presents how young children’s current practices when playing with tablets inform digital experiences in Denmark and Japan. Through an interdisciplinary lens and a grounded theory approach, I have identified and mapped...... vocabulary in children’s digital play experiences. These early digital experiences set the rules for the playgrounds and assert digital tablets as twenty-first-century toys, shaping young children’s playful literacy....

  4. Effects of the molar mass of the matrix on electrical properties, structure and morphology of plasticized PANI-PMMA blends

    International Nuclear Information System (INIS)

    Gmati, Fethi; Fattoum, Arbi; Bohli, Nadra; Mohamed, Abdellatif Belhadj

    2008-01-01

    The effects of the molar mass of polymethylmethacrylate (PMMA) on electrical, structural and morphological properties of conductive polyaniline-polymethylmethacrylate blends have been studied. We have plasticized the PMMA matrix by using dioctyl phthalate (DioPh). Three different molar masses of PMMA, 15 000, 120 000 and 350 000 g mol -1 , have been used. The x-ray diffraction analysis showed amorphous structure for all our studied PANI-PMMA blend films. The SEM micrographs showed more aggregation with the lowest molar mass of PMMA matrix. The direct current (dc) and alternating current (ac) electrical conductivities have been investigated in the temperature range 20-300 K and frequency range 7-1 x 10 8 Hz. The results of this study indicate an increase of the conductivity when the molar mass of PMMA decreases. With the lowest molar mass of PMMA (15 000 g mol -1 ), we obtained the lowest percolation threshold (p c ∼0.3%). The dc conductivity is governed by Mott's three-dimensional variable range hopping (3D VRH) model; different Mott's parameters have been evaluated. At high frequencies, the ac conductivity follows the power law σ(ω,T) = A(T)ω s(T,ω) , which is characteristic for charge transport in disordered materials by hopping or tunnelling processes. The observed decrease in the frequency exponent s with increasing temperature suggests that the correlated barrier hopping (CBH) model best describes the ac conduction mechanism. All our blends are well described by the scaling law σ(ω)/σ dc = 1+(ω/ω c ) n with n∼0.51-0.52

  5. Playful Interaction

    DEFF Research Database (Denmark)

    2003-01-01

    The video Playful Interaction describes a future architectural office, and envisions ideas and concepts for playful interactions between people, materials and appliances in a pervasive and augmented working environment. The video both describes existing developments, technologies and designs...... as well as ideas not yet implemented such as playful modes of interaction with an augmented ball. Playful Interaction has been used as a hybrid of a vision video and a video prototype (1). Externally the video has been used to visualising our new ideas, and internally the video has also worked to inspire...

  6. Mediatized play

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    Children’s play must nowadays be understood as a mediatized field in society and culture. Media – understood in a very broad sense - holds severe explanatory power in describing and understanding the practice of play, since play happens both with, through and inspired by media of different sorts........ In this presentation the case of ‘playing soccer’ will be outlined through its different mediated manifestations, including soccer games and programs on TV, computer games, magazines, books, YouTube videos and soccer trading cards....

  7. Play Practices and Play Moods

    DEFF Research Database (Denmark)

    Karoff, Helle Skovbjerg

    2013-01-01

    The aim of this article is to develop a view of play as a relation between play practices and play moods based on an empirical study of children's everyday life and by using Bateson's term of ‘framing’ [(1955/2001). In Steps to an ecology of mind (pp. 75–80). Chicago: University of Chicago Press......], Schmidt's notion of ‘commonness’ [(2005). Om respekten. København: Danmarks Pædagogiske Universitets Forlag; (2011). On respect. Copenhagen: Danish School of Education University Press] and Heidegger's term ‘mood’ [(1938/1996). Time and being. Cornwall: Wiley-Blackwell.]. Play mood is a state of being...... in which we are open and ready, both to others and their production of meaning and to new opportunities for producing meaning. This play mood is created when we engage with the world during play practices. The article points out four types of play moods – devotion, intensity, tension and euphorica – which...

  8. Playing Shakespeare.

    Science.gov (United States)

    Bashian, Kathleen Ryniker

    1993-01-01

    Describes a yearlong project at 12 Catholic middle schools in the Diocese of Arlington, Virginia, to incorporate the plays of William Shakespeare into the curriculum. Teachers attended university lectures and directed students in performances of the plays. Concludes that Shakespeare can be understood and enjoyed by middle school students. (BCY)

  9. ‘White revolution’ to ‘white pollution’—agricultural plastic film mulch in China

    Science.gov (United States)

    Liu, E. K.; He, W. Q.; Yan, C. R.

    2014-09-01

    Plastic film mulching has played an important role in Chinese agriculture due to its soil warming and moisture conservation effects. With the help of plastic film mulch technology, grain and cash crop yields have increased by 20-35% and 20-60%, respectively. The area of plastic film coverage in China reached approximately 20 million hectares, and the amount of plastic film used reached 1.25 million tons in 2011. While producing huge benefits, plastic film mulch technology has also brought on a series of pollution hazards. Large amounts of residual plastic film have detrimental effects on soil structure, water and nutrient transport and crop growth, thereby disrupting the agricultural environment and reducing crop production. To control pollution, the Chinese government urgently needs to elevate plastic film standards. Meanwhile, research and development of biodegradable mulch film and multi-functional mulch recovery machinery will help promote effective control and management of residual mulch pollution.

  10. Change in the structure and properties of carbon fiber-reinforced plastic with a polysulfone matrix under the effect of gamma irradiation

    International Nuclear Information System (INIS)

    Arkhipov, A.A.; Korkhov, V.P.; Pudnik, V.V.; Rodin, Yu.P.

    1993-01-01

    This article presents the results of studying the change in the structure and properties of carbon fiber-reinforced plastic with a thermoplastic matrix -- aromatic polysulfone -- as a function of the absorbed dose of gamma radiation. In view of the presence in the polysulfone macromolecules and in carbon fibers of a large number of aromatic rings and double bonds providing high radiation resistance of the composite, irradiation was carried out up to large values of absorbed doses (10 9 rad). Specimens of orthogonally reinforced composite KTMU-1 with a thickness of 1.3 mm made from aromatic polysulfone PSF-150 and carbon ribbon that absorbed various gamma radiation dosages were used. It was found that structural transformations under the effect of gamma radiation did not have a substantial effect on the mechanical properties of carbon fiber-reinforced plastic. 2 refs., 3 figs., 3 tabs

  11. Attenuation of stress waves in single and multi-layered structures. [mitigation of elastic and plastic stress waves during spacecraft landing

    Science.gov (United States)

    Yang, J. C. S.; Tsui, C. Y.

    1972-01-01

    Analytical and experimental studies were made of the attenuation of the stress waves during passage through single and multilayer structures. The investigation included studies on elastic and plastic stress wave propagation in the composites and those on shock mitigating material characteristics such as dynamic stress-strain relations and energy absorbing properties. The results of the studies are applied to methods for reducing the stresses imposed on a spacecraft during planetary or ocean landings.

  12. A work criterion for plastic collapse

    International Nuclear Information System (INIS)

    Muscat, Martin; Mackenzie, Donald; Hamilton, Robert

    2003-01-01

    A new criterion for evaluating limit and plastic loads in pressure vessel design by analysis is presented. The proposed criterion is based on the plastic work dissipated in the structure as loading progresses and may be used for structures subject to a single load or a combination of multiple loads. Example analyses show that limit and plastic loads given by the plastic work criterion are robust and consistent. The limit and plastic loads are determined purely by the inelastic response of the structure and are not influenced by the initial elastic response: a problem with some established plastic criteria

  13. Plastic dosimeter

    International Nuclear Information System (INIS)

    Nagai, Shiro; Matsuda, Kohji.

    1988-01-01

    The report outlines major features and applications of plastic dosimeters. Some plastic dosimeters, including the CTA and PVC types, detect the response of the plastic material itself to radiations while others, such as pigment-added plastic dosimeters, contain additives as radiation detecting material. Most of these dosimeters make use of color centers produced in the dosimeter by radiations. The PMMA dosimeter is widely used in the field of radiation sterilization of food, feed and medical apparatus. The blue cellophane dosimeter is easy to handle if calibrated appropriately. The rad-color dosimeter serves to determine whether products have been irradiated appropriately. The CTA dosimeter has better damp proofing properties than the blue cellophane type. The pigment-added plastic dosimeter consists of a resin such as nylon, CTA or PVC that contains a dye. Some other plastic dosimeters are also described briefly. Though having many advantages, these plastic dosimeter have disadvantages as well. Some of their major disadvantages, including fading as well as large dependence on dose, temperature, humidity and anviroment, are discussed. (Nogami, K.)

  14. PLASTIC SURGERY

    African Journals Online (AJOL)

    Department of Plastic and Reconstructive Surgery Sefako Makgatho Health Science University, ... We report on a pilot study on the use of a circumareolar excision and the use of .... and 1 gynecomastia patient) requested reduction in NAC size.

  15. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  16. Postphenomenological Play

    DEFF Research Database (Denmark)

    Hammar, Emil

    This paper aims to identify an understanding of digital games in virtual environments by using Don Ihde’s (1990) postphenomenological approach to how technology mediates the world to human beings in conjunction with Hans-Georg Gadamer’s (1993) notion of play . Through this tentatively proposed am...... amalgamation of theories I point towards an alternative understanding of the relationship between play and game as not only dialectic, but also as socially and ethically relevant qua the design and implementation of the game as technology....

  17. Elastic plastic fracture mechanics

    International Nuclear Information System (INIS)

    Simpson, L.A.

    1978-07-01

    The application of linear elastic fracture mechanics (LEFM) to crack stability in brittle structures is now well understood and widely applied. However, in many structural materials, crack propagation is accompanied by considerable crack-tip plasticity which invalidates the use of LEFM. Thus, present day research in fracture mechanics is aimed at developing parameters for predicting crack propagation under elastic-plastic conditions. These include critical crack-opening-displacement methods, the J integral and R-curve techniques. This report provides an introduction to these concepts and gives some examples of their applications. (author)

  18. The structural-phenomenological description of plastic anisotropy of H-1 and H-2.5 alloys, subjected to reactors irradiation

    International Nuclear Information System (INIS)

    Yamshchikov, N.V.; Prasolov, P.F.; Lebedinskij, K.B.

    1990-01-01

    The structural-phenomenological model of anisotropic single hpc textured polycrystals is described. The formulation of the present model is assumed that the polycrystal is continuous three-dimensional collection of transversal crystallites, the plastic properties which Hill's yield criteria are described. This model is allowed to determine six parameters in the Hill's yield criteria for ortho tropic materials based on only of uniaxial tension test in three directions and crystallographic texture. Yield surfaces of zircaloy alloys at 293 K and 623 K, subjected to irradiation in the reactor with total exposition dose 10 20 n/cm 2 are determined. Strongly influence of irradiation on the plastic behaviour of H-1 and H-2,5 alloys is observed. 2 refs.; 3 figs.; 2 tables. (author)

  19. Recent development of a CEC'S elasto-plastic-creep cyclic benchmark programme relevant to LMFBR structural integrity

    International Nuclear Information System (INIS)

    Corsi, F.; Terzaghi, A.

    1984-01-01

    It's presented the programme of elasto-plastic benchmark calculations relevant to LMFBr, which started in 1977 with the support and coordination of the Commission of the European Communities (CEC) and the participation of nuclear engineering and manufacturing companies as well as nuclear research centers of France, Germany, Italy and the United Kingdom. (E.G.) [pt

  20. Playful Organizations

    DEFF Research Database (Denmark)

    Pors, Justine Grønbæk; Åkerstrøm Andersen, Niels

    2015-01-01

    intact. In its final sections, the article discusses what happens to conditions of decision-making when organisations do not just see undecidability as a given condition, but as a limited resource indispensable for change and renewal. The article advances discussions of organisational play by exploring...

  1. Clay Play

    Science.gov (United States)

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  2. Sweet Play

    Science.gov (United States)

    Leung, Shuk-kwan S.; Lo, Jane-Jane

    2010-01-01

    This article features Sweet play math, a "math by the month" activity that involves decorating and making sugar cubes. Teachers may want to substitute straws, paper squares, alphabet blocks, or such commercially made manipulatives as Unifix[R] cubes for the real sweets. Given no allergy concerns, teachers and students alike would enjoy some sweet…

  3. Group play

    DEFF Research Database (Denmark)

    Tychsen, Anders; Hitchens, Michael; Brolund, Thea

    2008-01-01

    Role-playing games (RPGs) are a well-known game form, existing in a number of formats, including tabletop, live action, and various digital forms. Despite their popularity, empirical studies of these games are relatively rare. In particular there have been few examinations of the effects of the v......Role-playing games (RPGs) are a well-known game form, existing in a number of formats, including tabletop, live action, and various digital forms. Despite their popularity, empirical studies of these games are relatively rare. In particular there have been few examinations of the effects...... of the various formats used by RPGs on the gaming experience. This article presents the results of an empirical study, examining how multi-player tabletop RPGs are affected as they are ported to the digital medium. Issues examined include the use of disposition assessments to predict play experience, the effect...... of group dynamics, the influence of the fictional game characters and the comparative play experience between the two formats. The results indicate that group dynamics and the relationship between the players and their digital characters, are integral to the quality of the gaming experience in multiplayer...

  4. Playing Teacher.

    Science.gov (United States)

    Gilbert, Juan E.

    The acceptance of animation technologies is increasing. Video games, such as Sony PlayStation (SONY, 2002), have become part of the culture for young people from kindergarten through undergraduate school. Animation technologies have been implemented into educational systems in the form of animated pedagogical agents (Johnson, 2000). The research…

  5. Aesthetic Play

    DEFF Research Database (Denmark)

    Bang, Jytte Susanne

    2012-01-01

    The present article explores the role of music-related artefacts and technologies in children’s lives. More specifically, it analyzes how four 10- to 11-year old girls use CDs and DVD games in their music-play activities and which developmental themes and potentials may accrue from such activitie...

  6. Water Play

    Science.gov (United States)

    Cline, Jane E.; Smith, Brandy A.

    2016-01-01

    The inclusion of activities to develop sensory awareness, spatial thinking, and physical dexterity, operationalized through hands-on science lessons such as water play, have long been part of early childhood education. This practical article addresses Next Generation Science Standards K-2 ETS1-3 and K-2 ETS1-2 by having four-year-old…

  7. Does Performance in Digital Reading Relate to Computer Game Playing? A Study of Factor Structure and Gender Patterns in 15-Year-Olds' Reading Literacy Performance

    Science.gov (United States)

    Rasmusson, Maria; Åberg-Bengtsson, Lisbeth

    2015-01-01

    Data from a Swedish PISA-sample were used (1) to identify a digital reading factor, (2) to investigate gender differences in this factor (if found), and (3) to explore how computer game playing might relate to digital reading performance and gender. The analyses were conducted with structural equation modeling techniques. In addition to an overall…

  8. Using a Social Science--Fictional Play to Teach about Global Capitalism and Macro-Structural Systems in Introduction to Sociology

    Science.gov (United States)

    Pelak, Cynthia Fabrizio; Duncan, Stacey

    2017-01-01

    This article explores the use of a social science-fictional play to teach macro-structural concepts related to global capitalism and surplus labor in a small and large Introduction to Sociology course. Relying on a cross-disciplinary and critical pedagogical approach that combines theory and practice to empower students to develop a critical…

  9. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  10. Playing facilitator

    DEFF Research Database (Denmark)

    Houmøller, Ellen; Marchetti, Emanuela

    2015-01-01

    event called InnoEvent, addressed to students in the fields of multimedia and healthcare. Being interested in studying games and role-play as tools to support independent learning in the field of design thinking and team-building, following Dewey’s (1938) theory of learning experience, we ran two...... workshops based on two classic role-play games: The Silent Game (Brandt, 2006) and The Six Thinking Hats (de Bono, 1985). These games were created to support students in learning design thinking in groups and are assigned positive values in literature, hence we expected a smooth process. However, our...... experience was rather characterized by conflictual negotiations with the students. Data from our observations and from interviews with group representatives show that the students took a discontinuous learning path, characterised by a false start, failure, and a thorough reconsideration of their work...

  11. Playing at Work: The Intersection of Race, Class, and Gender with Power Structures of Work and Production.

    Science.gov (United States)

    Corrado, Marisa; Glasberg, Davita Silfen; Merenstein, Beth; Peele, Melanie R.

    2000-01-01

    Focuses on an exercise where students were assigned social roles based on gender, class, and race and then selected division of labor and reward structures in order to explore inequality in work and production. Offers a review of literature on the power structure of work and production and an evaluation of the exercise. (CMK)

  12. The CEASEMT system (Computer analysis of the thermomechanical structure behavior). The TRICO code, for analysis of three-dimensional structures comprising shells and beams - Statics - Dynamics - Elasticity - Plasticity - Buckling - Large displacements

    International Nuclear Information System (INIS)

    1977-01-01

    The TRICO part of the CEA-SEMT system is concerned with the elasticity or plasticity computation of structures made of thin shells and beams. TRICO uses the finite element method for shells and beams. TRICO also allows the dynamic computing of structures: search for eigenmodes and eigenfrequencies or response to any sinusoidal excitation, response to time dependent loads (direct integration) in elasticity or plasticity. The mechanical structures can offer any shape and be composed of a number of materials. A special effort has been put on data input (read without any format), the data being arranged in optional commands with a precise physical sense corresponding to an order for the program. A dynamic control of the memory allows the size of the program to be adapted to that the problem to be processed. Results are printed on listing, or many be described on a magnetic tape [fr

  13. Crystal structures reveal metal-binding plasticity at the metallo-β-lactamase active site of PqqB from Pseudomonas putida

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Xiongying; Latham, John A.; Klema, Valerie J.; Evans III, Robert L.; Li, Chao; Klinman, Judith P.; Wilmot, Carrie M. (UMM); (UCB)

    2017-08-19

    PqqB is an enzyme involved in the biosynthesis of pyrroloquinoline quinone and a distal member of the metallo-β-lactamase (MBL) superfamily. PqqB lacks two residues in the conserved signature motif HxHxDH that makes up the key metal-chelating elements that can bind up to two metal ions at the active site of MBLs and other members of its superfamily. Here, we report crystal structures of PqqB bound to Mn2+, Mg2+, Cu2+, and Zn2+. These structures demonstrate that PqqB can still bind metal ions at the canonical MBL active site. The fact that PqqB can adapt its side chains to chelate a wide spectrum of metal ions with different coordination features on a uniform main chain scaffold demonstrates its metal-binding plasticity. This plasticity may provide insights into the structural basis of promiscuous activities found in ensembles of metal complexes within this superfamily. Furthermore, PqqB belongs to a small subclass of MBLs that contain an additional CxCxxC motif that binds a structural Zn2+. Our data support a key role for this motif in dimerization.

  14. Plastic condoms.

    Science.gov (United States)

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  15. Playing Possum

    Directory of Open Access Journals (Sweden)

    Enrico Euli

    2016-07-01

    Full Text Available Our society is drenched in the catastrophe; where the growth of financial crisis, environmental cataclysm and militarization represents its gaudiest and mortifying phenomena. Humans struggle with depression, sense of impotence, anguish towards a future considered a threat.  A possibility to keep us alive can be represented by the enhancement of our ability in ‘playing Possum’, an exercise of desisting and renitence: to firmly say ‘no’. To say no to a world that proposes just one way of being and living free, that imposes as the only unavoidable possible destiny.

  16. Playful Technology

    DEFF Research Database (Denmark)

    Johansen, Stine Liv; Eriksson, Eva

    2013-01-01

    In this paper, the design of future services for children in Danish public libraries is discussed, in the light of new challenges and opportunities in relation to new media and technologies. The Danish government has over the last few years initiated and described a range of initiatives regarding...... in the library, the changing role of the librarians and the library space. We argue that intertwining traditional library services with new media forms and engaging play is the core challenge for future design in physical public libraries, but also that it is through new media and technology that new...

  17. Sustainable Corporate Social Media Marketing Based on Message Structural Features: Firm Size Plays a Significant Role as a Moderator

    OpenAIRE

    Moon Young Kang; Byungho Park

    2018-01-01

    Social media has been receiving attention as a cost-effective tool to build corporate brand image and to enrich customer relationships. This phenomenon calls for more attention to developing a model that measures the impact of structural features, used in corporate social media messages. Based on communication science, this study proposes a model to measure the impact of three essential message structural features (interactivity, formality, and immediacy) in corporate social media on customer...

  18. Correlation between synaptic plasticity, associated proteins, and rehabilitation training in a rat model of cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Dan Yang; Qian Yu

    2008-01-01

    All motions provide sensory, motoric, and reflexive input to the central nervous system, as well as playing an important role in cerebral functional plasticity and compensation. Cerebral plasticity has become the theoretical basis of neurorehabilitation. Studies of cerebrovascular disease, in particular, demonstrate that regeneration is accompanied by multiple forms of plasticity, such as functional and structural, in different phases of stroke rehabilitation. This study was designed to measure synaptic plasticity and expression of associated proteins to analyze the effect of rehabilitation training on learning and memory in a rat model of cerebral infarction. Results suggest that rehabilitation training increases expression of nerve growth factor associated protein 43, brain-derived neurotrophic factor, and neural cell adhesion molecules, and also promotes cerebral functional plasticity.

  19. Magical Engineering Plastic

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gwang Ung

    1988-01-15

    This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

  20. Magical Engineering Plastic

    International Nuclear Information System (INIS)

    Kim, Gwang Ung

    1988-01-01

    This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

  1. Structural damages prevention of the ITER vacuum vessel and ports by elasto-plastic analysis with regards to RCC-MR

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Jean-Marc, E-mail: jean-marc.martinez@iter.org [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Jun, Chang Hoon; Portafaix, Christophe; Alekseev, Alexander; Sborchia, Carlo; Choi, Chang-Ho [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Albin, Vincent [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France); Borrelly, Stephane [Sogeti High Tech, RE2, 180 rue René Descartes, Le Millenium – Bat C, 13857 Aix en Provence (France); Cambazar, Magali [Assystem EOS, 117 rue Jacquard, 84120 Pertuis (France); Gaucher, Thomas [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France); Sfarni, Samir; Tailhardat, Olivier [Assystem EOS, 117 rue Jacquard, 84120 Pertuis (France)

    2015-10-15

    Highlights: • ITER vacuum vessel (VV) is a part of the first barrier to confine the plasma. • ITER VV as NPE necessitates a third party organization authorized by the French nuclear regulator to assure design, fabrication, and conformance testing and quality assurance, i.e. ANB. • Several types of damages have to be prevented in order to guarantee the structural integrity with regards to RCC-MR. • It is usual to employ non-linear analysis when the “classical” elastic analysis reaches its limit of linear application. • Several structural analyses were performed with many different global and local models of the whole ITER VV. - Abstract: Several types of damages have to be prevented in order to guarantee the structural integrity of a structure with regards to RCC-MR; the P-type damages which can result from the application to a structure of a steadily and regularly increasing loading or a constant loading and the S-type damages during operational loading conditions which can only result from repeated application of loadings associated to the progressive deformations and fatigue. Following RCC-MR, the S-type damages prevention has to be started only when the structural integrity is guaranteed against P-type damages. The verification of the last one on the ITER vacuum vessel and ports has been performed by limit analysis with elasto-(perfectly)plastic material behavior. It is usual to employ non-linear analysis when the “classical” elastic analysis reaches its limit of linear application. Some elasto-plastic analyses have been performed considering several cyclic loadings to evaluate also more realistic structural margins of the against S-type damages.

  2. Correlative STED and Atomic Force Microscopy on Live Astrocytes Reveals Plasticity of Cytoskeletal Structure and Membrane Physical Properties during Polarized Migration

    Directory of Open Access Journals (Sweden)

    Nathalie Rouach

    2017-04-01

    Full Text Available The plasticity of the cytoskeleton architecture and membrane properties is important for the establishment of cell polarity, adhesion and migration. Here, we present a method which combines stimulated emission depletion (STED super-resolution imaging and atomic force microscopy (AFM to correlate cytoskeletal structural information with membrane physical properties in live astrocytes. Using STED compatible dyes for live cell imaging of the cytoskeleton, and simultaneously mapping the cell surface topology with AFM, we obtain unprecedented detail of highly organized networks of actin and microtubules in astrocytes. Combining mechanical data from AFM with optical imaging of actin and tubulin further reveals links between cytoskeleton organization and membrane properties. Using this methodology we illustrate that scratch-induced migration induces cytoskeleton remodeling. The latter is caused by a polarization of actin and microtubule elements within astroglial cell processes, which correlates strongly with changes in cell stiffness. The method opens new avenues for the dynamic probing of the membrane structural and functional plasticity of living brain cells. It is a powerful tool for providing new insights into mechanisms of cell structural remodeling during physiological or pathological processes, such as brain development or tumorigenesis.

  3. THC alters alters morphology of neurons in medial prefrontal cortex, orbital prefrontal cortex, and nucleus accumbens and alters the ability of later experience to promote structural plasticity.

    Science.gov (United States)

    Kolb, Bryan; Li, Yilin; Robinson, Terry; Parker, Linda A

    2018-03-01

    Psychoactive drugs have the ability to alter the morphology of neuronal dendrites and spines and to influence later experience-dependent structural plasticity. If rats are given repeated injections of psychomotor stimulants (amphetamine, cocaine, nicotine) prior to being placed in complex environments, the drug experience interferes with the ability of the environment to increase dendritic arborization and spine density. Repeated exposure to Delta 9-Tetrahydrocannabinol (THC) changes the morphology of dendrites in medial prefrontal cortex (mPFC) and nucleus accumbens (NAcc). To determine if drugs other than psychomotor stimulants will also interfere with later experience-dependent structural plasticity we gave Long-Evans rats THC (0.5 mg/kg) or saline for 11 days before placing them in complex environments or standard laboratory caging for 90 days. Brains were subsequently processed for Golgi-Cox staining and analysis of dendritic morphology and spine density mPFC, orbital frontal cortex (OFC), and NAcc. THC altered both dendritic arborization and spine density in all three regions, and, like psychomotor stimulants, THC influenced the effect of later experience in complex environments to shape the structure of neurons in these three regions. We conclude that THC may therefore contribute to persistent behavioral and cognitive deficits associated with prolonged use of the drug. © 2017 Wiley Periodicals, Inc.

  4. Mixed plastics recycling technology

    CERN Document Server

    Hegberg, Bruce

    1995-01-01

    Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

  5. Pervasive plastic

    Science.gov (United States)

    2018-05-01

    Human manipulation of hydrocarbons — as fuel and raw materials for modern society — has changed our world and the indelible imprint we will leave in the rock record. Plastics alone have permeated our lives and every corner of our planet.

  6. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  7. Plastic deformation

    NARCIS (Netherlands)

    Sitter, de L.U.

    1937-01-01

    § 1. Plastic deformation of solid matter under high confining pressures has been insufficiently studied. Jeffreys 1) devotes a few paragraphs to deformation of solid matter as a preface to his chapter on the isostasy problem. He distinguishes two properties of solid matter with regard to its

  8. Independent mobility, perceptions of the built environment and children's participation in play, active travel and structured exercise and sport: the PEACH Project

    Directory of Open Access Journals (Sweden)

    Griew Pippa

    2010-02-01

    Full Text Available Abstract Background Independent mobility (IM and perceptions of the built environment may relate differentially to children's participation in various physical activity contexts. This cross-sectional study investigated whether independent mobility and perceptions of the built environment in boys and girls were related to physical activity in three different contexts (outdoor play, structured exercise/sport, active commuting. Methods Thirteen hundred and seven 10-11 year old boys and girls from 23 schools in a large UK city completed a computerised questionnaire. Independent variables in logistic regression analyses were weekly self-reported frequency of participation in outdoor play, structured exercise/sport and mode of travel home from school. Dependent variables were perceptions of the environment (aesthetics, nuisance, safety, social norm, constraint, play space, accessibility, local and area independent mobility and linear distance from home to school. Analyses were adjusted for body mass index, minutes of daylight after school, level of neighbourhood deprivation and pubertal status. Results For boys, local independent mobility (Local-IM was related to an increased likelihood of everyday participation in play (OR 1.58: 95% CI 1.19-2.10, structured exercise/sport (OR 1.42: 1.06-1.89 and active commuting (OR 1.40: 1.07-1.87 but was only related to active commuting for girls (OR1.49: 1.07-2.07. Boys and girls were more likely to report playing out every day if they had higher scores for Social Norm (Boys: OR 1.63 (1.12-2.37; Girls: OR 1.53 (1.01-2.31 and, for girls only, more positive perceptions of traffic safety (OR 1.63: 1.14-2.34. Easy access to a range of destinations was the dominant predictor for taking part in structured exercise/sport everyday (Boys: OR 1.62 (1.01-2.66; Girls: OR 1.65 (1.07-2.53. Shorter distance from home to school (OR 0.99: 0.98-0.99 and, for boys only, greater perceived accessibility (OR 1.87: 1.04-3.36 were

  9. High-Temperature Structural Analysis of a Small-Scale Prototype of a Process Heat Exchanger (IV) - Macroscopic High-Temperature Elastic-Plastic Analysis -

    International Nuclear Information System (INIS)

    Song, Kee Nam; Hong, Sung Deok; Park, Hong Yoon

    2011-01-01

    A PHE (Process Heat Exchanger) is a key component required to transfer heat energy of 950 .deg. C generated in a VHTR (Very High Temperature Reactor) to a chemical reaction that yields a large quantity of hydrogen. A small-scale PHE prototype made of Hastelloy-X was scheduled for testing in a small-scale gas loop at the Korea Atomic Energy Research Institute. In this study, as a part of the evaluation of the high-temperature structural integrity of the PHE prototype, high-temperature structural analysis modeling, and macroscopic thermal and elastic-plastic structural analysis of the PHE prototype were carried out under the gas-loop test conditions as a preliminary qwer123$ study before carrying out the performance test in the gas loop. The results obtained in this study will be used to design the performance test setup for the modified PHE prototype

  10. Comics and the Structure of Childhood Feeling: Sublimation and the Play of Pretending in Gilbert Hernandez's "Marble Season"

    Science.gov (United States)

    Lewkowich, David

    2016-01-01

    In this paper, I study the narrative structure of comics as a means to describe the ways that indeterminate modes of representation can allow the reader to imagine that which in childhood can never be fully expressed. Analyzing a number of panels from Gilbert Hernandez's graphic novel, "Marble Season," I describe a conceptual link…

  11. Progressive deformation of ultramafic rocks accompanied with deflection of layered structure and mylonitization culminating into a pseudotachylyte-bearing seismogenic fault - a field evidence of plastic instability

    Science.gov (United States)

    Ueda, T.; Obata, M.

    2011-12-01

    Plastic instability leading to rupture nucleation and propagetion (e.g. Hobbs et al.1986, Kelemen and Hirth, 2007) is an attractive hypothesis for deep earthquakes but lacked clear field evidences. 1D across-fault shear localization observed in some places (e.g. Jin et al.1998) is not clear if the deformation is directly related with seismicity. We present a clear field evidence of plastic instability as guided by pyroxenite/peridotite layering deflection structure (hereafter called LD structure, see figure) accompanied with mylonitization in spinel(Sp)-peridotite facies (P>~1GPa) in Balmuccia peridotite, Ivrea-Verbano Zone, Italy. The studied area contains abundant PST-bearing faults and N-S trending primary pyroxenite layers. Many faults in the area cut pyroxenite layers, but LD structure is found only in one place presented here. Many PSTs in the area have been (re)crystallized in Sp-peridotite facies, and have typically ultramylonitic texture (Ueda et al., 2008) with some injection veins. The fault with LD structure is situated in a fault system, which has two dominant attitudes with regional N-S extension. The shear strain of LD structure measured on outcrop surface is ~2.0. Near the fault, elongated Opx porphyroclasts (ellipses in figure) oblique to local layering are visible in peridotite. The dominant deformation textures are dynamic recrystallization in peridotite and kinking or undulatory extinction in pyroxenite. The mineral assemblages of the mylonite neoblast in the peridotite and the pyroxenite are Ol+Opx+Cpx+Sp+hornblende(Hbl), Cpx+Opx+Sp, respectively. Hbl typically occur only in neoblast. In the vicinity (several hundreds of micron) of the fault, dolomite(Dol) also occur in equilibrium with the assemblage above. The recrystallized grain sizes are 20-50 microns in peridotite and 10-30 microns in pyroxenite. The rarity of LD structure is consistent with general conception that deformation processes which lead to dynamic rupture initiation ought to be

  12. Cholesterol biosensor based on a plastic optical fibre with sol-gel: structural analysis and sensing properties

    Science.gov (United States)

    Razo-Medina, D. A.; Trejo-Durán, M.; Alvarado-Méndez, E.

    2018-02-01

    In this paper, we report the design and characterization of an optical fibre cholesterol biosensor by using sol-gel immobilization technique. The cholesterol enzyme is encapsulated inside of the sol-gel film onto an end of a plastic optical fibre. Two film deposition methods (Dip-Coating and Immersion) were studied. The morphology analysis and sensing properties permit us to determine the best film deposition to sense cholesterol concentration. The range of measured is 4.4-5.2 mM in real time and our results were validated by comparing them with other previously published results. The biosensor is portable, simple cheap, and easy to use.

  13. Sustainable Corporate Social Media Marketing Based on Message Structural Features: Firm Size Plays a Significant Role as a Moderator

    Directory of Open Access Journals (Sweden)

    Moon Young Kang

    2018-04-01

    Full Text Available Social media has been receiving attention as a cost-effective tool to build corporate brand image and to enrich customer relationships. This phenomenon calls for more attention to developing a model that measures the impact of structural features, used in corporate social media messages. Based on communication science, this study proposes a model to measure the impact of three essential message structural features (interactivity, formality, and immediacy in corporate social media on customers’ purchase intentions, mediated by brand attitude and corporate trust. Especially, social media platforms are believed to provide a good marketing platform for small and medium enterprises (SMEs by providing access to huge audiences at a very low cost. The findings from this study based on a structural equation model suggest that brand attitude and corporate trust have larger impacts on purchase intention for SMEs than large firms. This implies that SMEs with little to no presence in the market should pay more attention to building corporate trust and brand attitude for their sustainable growth.

  14. Secular trends in overweight and obesity among Icelandic adolescents: do parental education levels and family structure play a part?

    Science.gov (United States)

    Eidsdóttir, Sigridur Þ; Kristjánsson, Álfgeir l; Sigfúsdóttir, Inga D; Garber, Carol E; Allegrante, John P

    2013-06-01

    To investigate whether the secular trend in the increasing prevalence of overweight and obesity among 16- to 20-year-old adolescents in Iceland varied by levels of parental education and family structure. Odds ratios were calculated from repeated population-based, cross-sectional surveys comprising cohorts of 16- to 20-year-old Icelandic adolescents attending junior colleges in 1992 (n=4,922), 2004 (n=11,031), 2007 (n=11,229), and 2010 (n=11,388). Body mass index (BMI) was calculated from self-reported weight and height and categorised as normal weight or overweight and obese, and examined in relation to parental education level and family structure. The odds of being overweight increased by 2.62 and 1.71 for boys and girls respectively over each of the survey time points. The prevalence of overweight and obesity increased across all three subgroups (low, medium, and high) of parental education level. The probability of overweight across all years were consistently the highest for youths with parents in the low-education category followed by middle-educated and high-educated parental background (peducation backgrounds increased over time and was generally explained more by the fathers' education than by the mothers' education (pFamily structure was not associated with the prevalence of overweight and obesity in our data. Differences in parental levels of education are associated with accelerating trends in prevalence of overweight and obesity among 16- to 20-year-old adolescents in Iceland.

  15. Neural stem cells and neuro/gliogenesis in the central nervous system: understanding the structural and functional plasticity of the developing, mature, and diseased brain.

    Science.gov (United States)

    Yamaguchi, Masahiro; Seki, Tatsunori; Imayoshi, Itaru; Tamamaki, Nobuaki; Hayashi, Yoshitaka; Tatebayashi, Yoshitaka; Hitoshi, Seiji

    2016-05-01

    Neurons and glia in the central nervous system (CNS) originate from neural stem cells (NSCs). Knowledge of the mechanisms of neuro/gliogenesis from NSCs is fundamental to our understanding of how complex brain architecture and function develop. NSCs are present not only in the developing brain but also in the mature brain in adults. Adult neurogenesis likely provides remarkable plasticity to the mature brain. In addition, recent progress in basic research in mental disorders suggests an etiological link with impaired neuro/gliogenesis in particular brain regions. Here, we review the recent progress and discuss future directions in stem cell and neuro/gliogenesis biology by introducing several topics presented at a joint meeting of the Japanese Association of Anatomists and the Physiological Society of Japan in 2015. Collectively, these topics indicated that neuro/gliogenesis from NSCs is a common event occurring in many brain regions at various ages in animals. Given that significant structural and functional changes in cells and neural networks are accompanied by neuro/gliogenesis from NSCs and the integration of newly generated cells into the network, stem cell and neuro/gliogenesis biology provides a good platform from which to develop an integrated understanding of the structural and functional plasticity that underlies the development of the CNS, its remodeling in adulthood, and the recovery from diseases that affect it.

  16. Ropinirole and Pramipexole Promote Structural Plasticity in Human iPSC-Derived Dopaminergic Neurons via BDNF and mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Ginetta Collo

    2018-01-01

    Full Text Available The antiparkinsonian ropinirole and pramipexole are D3 receptor- (D3R- preferring dopaminergic (DA agonists used as adjunctive therapeutics for the treatment resistant depression (TRD. While the exact antidepressant mechanism of action remains uncertain, a role for D3R in the restoration of impaired neuroplasticity occurring in TRD has been proposed. Since D3R agonists are highly expressed on DA neurons in humans, we studied the effect of ropinirole and pramipexole on structural plasticity using a translational model of human-inducible pluripotent stem cells (hiPSCs. Two hiPSC clones from healthy donors were differentiated into midbrain DA neurons. Ropinirole and pramipexole produced dose-dependent increases of dendritic arborization and soma size after 3 days of culture, effects antagonized by the selective D3R antagonists SB277011-A and S33084 and by the mTOR pathway kinase inhibitors LY294002 and rapamycin. All treatments were also effective in attenuating the D3R-dependent increase of p70S6-kinase phosphorylation. Immunoneutralisation of BDNF, inhibition of TrkB receptors, and blockade of MEK-ERK signaling likewise prevented ropinirole-induced structural plasticity, suggesting a critical interaction between BDNF and D3R signaling pathways. The highly similar profiles of data acquired with DA neurons derived from two hiPSC clones underpin their reliability for characterization of pharmacological agents acting via dopaminergic mechanisms.

  17. plastic waste recycling

    African Journals Online (AJOL)

    Dr Ahmed

    incinerators is increasing around the world. Discarded plastic products ... Agency (EPA) estimated that the amount of plastics throw away is. 50 % greater in the ... The waste plastics were identified using the Society of the Plastic. Industry (SPI) ...

  18. Juvenile neurogenesis makes essential contributions to adult brain structure and plays a sex-dependent role in fear memories

    Directory of Open Access Journals (Sweden)

    Jesse Daniel Cushman

    2012-02-01

    Full Text Available Postnatal-neurogenesis (PNN contributes neurons to olfactory bulb (OB and dentate gyrus (DG throughout juvenile development, but the quantitative amount, temporal dynamics and functional roles of this contribution have not been defined. By using transgenic mouse models for cell lineage tracing and conditional cell ablation, we found that juvenile neurogenesis gradually increased the total number of granule neurons by approximately 40% in OB, and by 25% in DG, between two weeks and two months of age, and that total numbers remained stable thereafter. These findings indicate that the overwhelming majority of net postnatal neuronal addition in these regions occurs during the juvenile period and that adult neurogenesis contributes primarily to replacement of granule cells in both regions. Behavioral analysis in our conditional cell ablation mouse model showed that complete loss of PNN throughout both the juvenile and adult period produced a specific set of sex-dependent cognitive changes. We observed normal hippocampus-independent delay fear conditioning, but excessive generalization of fear to a novel auditory stimulus, which is consistent with a role for PNN in psychopathology. Standard contextual fear conditioning was intact, however, pre-exposure dependent contextual fear was impaired suggesting a specific role for PNN in incidental contextual learning. Contextual discrimination between two highly similar contexts was enhanced; suggesting either enhanced contextual pattern separation or impaired temporal integration. We also observed a reduced reliance on olfactory cues, consistent with a role for OB PNN in the efficient processing of olfactory information. Thus, juvenile neurogenesis adds substantively to the total numbers of granule neurons in OB and DG during periods of critical juvenile behavioral development, including weaning, early social interactions and sexual maturation, and plays a sex-dependent role in fear memories.

  19. Structured Parent-Child Observations Predict Development of Conduct Problems: the Importance of Parental Negative Attention in Child-Directed Play.

    Science.gov (United States)

    Fleming, Andrew P; McMahon, Robert J; King, Kevin M

    2017-04-01

    Structured observations of parent-child interactions are commonly used in research and clinical settings, but require additional empirical support. The current study examined the capacity of child-directed play, parent-directed play, and parent-directed chore interaction analogs to uniquely predict the development of conduct problems across a 6-year follow-up period. Parent-child observations were collected from 338 families from high-risk neighborhoods during the summer following the child's first-grade year. Participating children were 49.2 % female, 54.4 % white, and 45.6 % black, and had an average age of 7.52 years at the first assessment. Conduct problems were assessed via parent report and teacher report at five assessment points between first grade and seventh grade. Latent growth curve modeling was used to analyze predictors of conduct problem trajectory across this 6-year follow-up period. When race, sex, socioeconomic status, and maternal depressive symptoms were controlled, parental negative attention during child-directed play predicted higher levels of parent-reported conduct problems concurrently and after a 6-year follow-up period. Parental negative attention during child-directed play also predicted higher teacher-reported conduct problems 6 years later. Findings support the use of child-directed play and parent-directed chore analogs in predicting longitudinal development of conduct problems. The presence of parental negative attention during child-directed play appears to be an especially important predictor of greater conduct problems over time and across multiple domains. Additionally, the potential importance of task-incongruent behavior is proposed for further study.

  20. Structure and petroleum plays of the St. Lawrence Platform and Appalachians in southern Quebec : insights from interpretation of MRNQ seismic reflection data

    Energy Technology Data Exchange (ETDEWEB)

    Castonguay, S.; Lavoie, D. [Natural Resources Canada, Quebec, PQ (Canada). Geological Survey of Canada, Quebec Division; Dietrich, J. [Natural Resources Canada, Calgary, AB (Canada). Geological Survey of Canada; Laliberte, J.Y. [Ministere des Ressources naturelles et de la Faune du Quebec, Charlesbourg, QC (Canada). Direction generale des hydrocarbures et des biocarburants

    2010-09-15

    This paper presented the results of a study in which 3 regional seismic reflection lines originally acquired in 1978 were reprocessed and reinterpreted using current techniques and methodologies. The profiles cross the Chambly-Fortierville syncline and provide images of the St. Lawrence Platform and the Appalachian foreland thrust belt of southern Quebec, including one that spans the entire width of the southern Quebec Appalachians. Post-stack seismic data processing and time migration were used to improve the quality of the original seismic sections, allowing interpretations that provide new information on subsurface geology, such as the recognition of complex structural patterns in platform and foreland units, the presence of a triangle zone at the structural front, and the geometry of thrust slices of platform units and Appalachian thrust beds, as well as images of the internal Humber Zone, including back-thrust faults and mega thrust wedges. The Saint-Flavien natural gas-field and other potential targets in the St. Lawrence Platform and Appalachian Foreland are imaged in the seismic profiles. The study provided new insights into the structure, geological evolution, and petroleum potential of the St. Lawrence Platform and the Appalachian foreland thrust belt of southern Quebec, including a potential, previously unrecognized Ordovician hydrothermal dolomite play. The new subsurface interpretations give a clearer view of the major structure affecting the Utica Shale, providing new insights into the limits of the unconventional shale gas play in the St. Lawrence Platform. 53 refs., 8 figs.

  1. Durability of wood plastic composites manufactured from recycled plastic

    Directory of Open Access Journals (Sweden)

    Irina Turku

    2018-03-01

    Full Text Available The influence of accelerated weathering, xenon-arc light and freeze-thaw cycling on wood plastic composites extruded from a recycled plastic was studied. The results showed that, in general, weathering had a stronger impact on samples made from plastic waste compared to a sample made from virgin material. After weathering, the mechanical properties, tensile and flexural, were reduced by 2–30%, depending on the plastic source. Wettability of the samples was shown to play a significant role in their stability. Chemical analysis with infrared spectroscopy and surface observation with a scan electron microscope confirmed the mechanical test results. Incorporation of carbon black retained the properties during weathering, reducing the wettability of the sample, diminishing the change of mechanical properties, and improving color stability. Keywords: Environmental science, Mechanical engineering, Materials science

  2. Cholinergic Potentiation and Audiovisual Repetition-Imitation Therapy Improve Speech Production and Communication Deficits in a Person with Crossed Aphasia by Inducing Structural Plasticity in White Matter Tracts.

    Science.gov (United States)

    Berthier, Marcelo L; De-Torres, Irene; Paredes-Pacheco, José; Roé-Vellvé, Núria; Thurnhofer-Hemsi, Karl; Torres-Prioris, María J; Alfaro, Francisco; Moreno-Torres, Ignacio; López-Barroso, Diana; Dávila, Guadalupe

    2017-01-01

    Donepezil (DP), a cognitive-enhancing drug targeting the cholinergic system, combined with massed sentence repetition training augmented and speeded up recovery of speech production deficits in patients with chronic conduction aphasia and extensive left hemisphere infarctions (Berthier et al., 2014). Nevertheless, a still unsettled question is whether such improvements correlate with restorative structural changes in gray matter and white matter pathways mediating speech production. In the present study, we used pharmacological magnetic resonance imaging to study treatment-induced brain changes in gray matter and white matter tracts in a right-handed male with chronic conduction aphasia and a right subcortical lesion (crossed aphasia). A single-patient, open-label multiple-baseline design incorporating two different treatments and two post-treatment evaluations was used. The patient received an initial dose of DP (5 mg/day) which was maintained during 4 weeks and then titrated up to 10 mg/day and administered alone (without aphasia therapy) during 8 weeks (Endpoint 1). Thereafter, the drug was combined with an audiovisual repetition-imitation therapy (Look-Listen-Repeat, LLR) during 3 months (Endpoint 2). Language evaluations, diffusion weighted imaging (DWI), and voxel-based morphometry (VBM) were performed at baseline and at both endpoints in JAM and once in 21 healthy control males. Treatment with DP alone and combined with LLR therapy induced marked improvement in aphasia and communication deficits as well as in selected measures of connected speech production, and phrase repetition. The obtained gains in speech production remained well-above baseline scores even 4 months after ending combined therapy. Longitudinal DWI showed structural plasticity in the right frontal aslant tract and direct segment of the arcuate fasciculus with both interventions. VBM revealed no structural changes in other white matter tracts nor in cortical areas linked by these tracts. In

  3. Structural plasticity of Barley yellow dwarf virus-like cap-independent translation elements in four genera of plant viral RNAs.

    Science.gov (United States)

    Wang, Zhaohui; Kraft, Jelena J; Hui, Alice Y; Miller, W Allen

    2010-06-20

    The 3' untranslated regions (UTRs) of many plant viral RNAs contain cap-independent translation elements (3' CITEs). Among the 3' CITEs, the Barley yellow dwarf virus (BYDV)-like translation elements (BTEs) form a structurally variable and widely distributed group. Viruses in three genera were known to harbor 3' BTEs, defined by the presence of a 17-nt consensus sequence. To understand BTE function, knowledge of phylogenetically conserved structure is essential, yet the secondary structure has been determined only for the BYDV BTE. Here we show that Rose spring dwarf-associated luteovirus, and two viruses in a fourth genus, Umbravirus, contain functional BTEs, despite deviating in the 17nt consensus sequence. Structure probing by selective 2'-hydroxyl acylation and primer extension (SHAPE) revealed conserved and highly variable structures in BTEs in all four genera. We conclude that BTEs tolerate striking evolutionary plasticity in structure, while retaining the ability to stimulate cap-independent translation. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  4. Phenotypic plasticity in haptoral structures of Ligophorus cephali (Monogenea: Dactylogyridae) on the flathead mullet (Mugil cephalus): a geometric morphometric approach.

    Science.gov (United States)

    Rodríguez-González, Abril; Míguez-Lozano, Raúl; Llopis-Belenguer, Cristina; Balbuena, Juan Antonio

    2015-04-01

    Evaluating phenotypic plasticity in attachment organs of parasites can provide information on the capacity to colonise new hosts and illuminate evolutionary processes driving host specificity. We analysed the variability in shape and size of the dorsal and ventral anchors of Ligophorus cephali from Mugil cephalus by means of geometric morphometrics and multivariate statistics. We also assessed the morphological integration between anchors and between the roots and points in order to gain insight into their functional morphology. Dorsal and ventral anchors showed a similar gradient of overall shape variation, but the amount of localised changes was much higher in the former. Statistical models describing variations in shape and size revealed clear differences between anchors. The dorsal anchor/bar complex seems more mobile than the ventral one in Ligophorus, and these differences may reflect different functional roles in attachment to the gills. The lower residual variation associated with the ventral anchor models suggests a tighter control of their shape and size, perhaps because these anchors seem to be responsible for firmer attachment and their size and shape would allow more effective responses to characteristics of the microenvironment within the individual host. Despite these putative functional differences, the high level of morphological integration indicates a concerted action between anchors. In addition, we found a slight, although significant, morphological integration between roots and points in both anchors, which suggests that a large fraction of the observed phenotypic variation does not compromise the functional role of anchors as levers. Given the low level of genetic variation in our sample, it is likely that much of the morphological variation reflects host-driven plastic responses. This supports the hypothesis of monogenean specificity through host-switching and rapid speciation. The present study demonstrates the potential of geometric

  5. Imaging brain plasticity after trauma

    Institute of Scientific and Technical Information of China (English)

    Zhifeng Kou; Armin Iraji

    2014-01-01

    The brain is highly plastic after stroke or epilepsy;however, there is a paucity of brain plasticity investigation after traumatic brain injury (TBI). This mini review summarizes the most recent evidence of brain plasticity in human TBI patients from the perspective of advanced magnetic resonance imaging. Similar to other forms of acquired brain injury, TBI patients also demonstrat-ed both structural reorganization as well as functional compensation by the recruitment of other brain regions. However, the large scale brain network alterations after TBI are still unknown, and the ifeld is still short of proper means on how to guide the choice of TBI rehabilitation or treat-ment plan to promote brain plasticity. The authors also point out the new direction of brain plas-ticity investigation.

  6. Computational strain gradient crystal plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2014-01-01

    A numerical method for viscous strain gradient crystal plasticity theory is presented, which incorporates both energetic and dissipative gradient effects. The underlying minimum principles are discussed as well as convergence properties of the proposed finite element procedure. Three problems...... of plane crystal plasticity are studied: pure shear of a single crystal between rigid platens as well as plastic deformation around cylindrical voids in hexagonal close packed and face centered cubic crystals. Effective in-plane constitutive slip parameters for plane strain deformation of specifically...... oriented face centered cubic crystals are developed in terms of the crystallographic slip parameters. The effect on geometrically necessary dislocation structures introduced by plastic deformation is investigated as a function of the ratio of void radius to plasticity length scale....

  7. Contribution to the numerical study of concrete behaviour and of reinforced concrete structures submitted to coupled thermal and mechanical solicitations: a damageable thermo-elasto-plastic approach

    International Nuclear Information System (INIS)

    Nechnech, W.

    2000-12-01

    The aim of this research is the development of an Finite Element model for the analysis of reinforced concrete structures under thermal, mechanical loadings or any combination of them. An available synthesis of results on the concrete behavior under thermal solicitation is exposed. The different behavior of concrete that can be founded notably in thermo-mechanical analysis (Damage, unilateral phenomenon, thermo-mechanical interaction,...) are underlined. The various families of modeling are analyzed thereafter while underlining the important aspects of the behavior that each one can re-transcribe. A new thermo-plastic damage model for plain concrete subjected to combined thermal and cyclic loading is developed using the concept of plastic-work-hardening and stiffness degradation in continuum damage mechanics. Two damage variables are used: the first one for mechanical action and the second one for thermal action. Further, thermo-mechanical interaction strains have been introduced to describe the influence of mechanical loading on the physical process of thermal expansion of concrete. The constitutive relations for elastoplastic responses are decoupled from the degradation damage responses by using the effective stress concept. This method provides advantages in the numerical implementation. A simple and thermodynamically consistent scalar degradation model is introduced to simulate the effect of damage on elastic stiffness and its recovery during crack opening and closing. Efficient computational algorithms for the proposed model are subsequently explored and performance of this model is demonstrated with numerical examples. (author)

  8. A Lesson Plan to Develop Structured Discussion of the Benefits and Disadvantages of Selected Plastics Using the Product-Testing Method

    Science.gov (United States)

    Burmeister, Mareike; Eilks, Ingo

    2014-01-01

    People use many different products made from plastics every day. But conventional plastics such as polyvinyl chloride (PVC) do not always have a good reputation in society at large. Bioplastics such as thermoplastic starch (TPS) promise to be better alternatives but are they really better than conventional plastics? This article presents a new…

  9. Temporal changes of CB1 cannabinoid receptor in the basal ganglia as a possible structure-specific plasticity process in 6-OHDA lesioned rats.

    Directory of Open Access Journals (Sweden)

    Gabriela P Chaves-Kirsten

    Full Text Available The endocannabinoid system has been implicated in several neurobiological processes, including neurodegeneration, neuroprotection and neuronal plasticity. The CB1 cannabinoid receptors are abundantly expressed in the basal ganglia, the circuitry that is mostly affected in Parkinson's Disease (PD. Some studies show variation of CB1 expression in basal ganglia in different animal models of PD, however the results are quite controversial, due to the differences in the procedures employed to induce the parkinsonism and the periods analyzed after the lesion. The present study evaluated the CB1 expression in four basal ganglia structures, namely striatum, external globus pallidus (EGP, internal globus pallidus (IGP and substantia nigra pars reticulata (SNpr of rats 1, 5, 10, 20, and 60 days after unilateral intrastriatal 6-hydroxydopamine injections, that causes retrograde dopaminergic degeneration. We also investigated tyrosine hydroxylase (TH, parvalbumin, calbindin and glutamic acid decarboxylase (GAD expression to verify the status of dopaminergic and GABAergic systems. We observed a structure-specific modulation of CB1 expression at different periods after lesions. In general, there were no changes in the striatum, decreased CB1 in IGP and SNpr and increased CB1 in EGP, but this increase was not sustained over time. No changes in GAD and parvalbumin expression were observed in basal ganglia, whereas TH levels were decreased and the calbindin increased in striatum in short periods after lesion. We believe that the structure-specific variation of CB1 in basal ganglia in the 6-hydroxydopamine PD model could be related to a compensatory process involving the GABAergic transmission, which is impaired due to the lack of dopamine. Our data, therefore, suggest that the changes of CB1 and calbindin expression may represent a plasticity process in this PD model.

  10. What is behind the plastic strain rate?

    NARCIS (Netherlands)

    Hütter, M.; Grmela, M.; Öttinger, H.C.

    2009-01-01

    The plastic strain rate plays a central role in macroscopic models on elasto-viscoplasticity. In order to discuss the concept behind this quantity, we propose, first, a kinetic toy model to describe the dynamics of sliding layers representative of plastic deformation of single crystalline metals.

  11. Structural Analysis of Shipping Casks, Vol. 9. Energy Absorption Capabilities of Plastically Deformed Struts Under Specified Impact Loading Conditions (Thesis)

    International Nuclear Information System (INIS)

    Davis, F.C.

    2001-01-01

    The purpose of this investigation was to determine the energy absorption characteristics of plastically deformed inclined struts under impact loading. This information is needed to provide a usable method by which designers and analysts of shipping casks for radioactive or fissile materials can determine the energy absorption capabilities of external longitudinal fins on cylindrical casks under specified impact conditions. A survey of technical literature related to experimental determination of the dynamic plastic behavior of struts revealed no information directly applicable to the immediate problem, especially in the impact velocity ranges desired, and an experimental program was conducted to obtain the needed data. Mild-steel struts with rectangular cross sections were impacted by free-falling weights dropped from known heights. These struts or fin specimens were inclined at five different angles to simulate different angles of impact that fins on a shipping cask could experience under certain accident conditions. The resisting force of the deforming strut was measured and recorded as a function of time by using load cells instrumented with resistance strain gage bridges, signal conditioning equipment, an oscilloscope, and a Polaroid camera. The acceleration of the impacting weight was measured and recorded as a function of time during the latter portion of the testing program by using an accelerometer attached to the drop hammer, appropriate signal conditioning equipment, the oscilloscope, and the camera. A digital computer program was prepared to numerically integrate the force-time and acceleration-time data recorded during the tests to obtain deformation-time data. The force-displacement relationships were then integrated to obtain values of absorbed energy with respect to deformation or time. The results for various fin specimen geometries and impact angles are presented graphically, and these curves may be used to compute the energy absorption capacity of

  12. Fragile X Mental Retardation Protein and Dendritic Local Translation of the Alpha Subunit of the Calcium/Calmodulin-Dependent Kinase II Messenger RNA Are Required for the Structural Plasticity Underlying Olfactory Learning.

    Science.gov (United States)

    Daroles, Laura; Gribaudo, Simona; Doulazmi, Mohamed; Scotto-Lomassese, Sophie; Dubacq, Caroline; Mandairon, Nathalie; Greer, Charles August; Didier, Anne; Trembleau, Alain; Caillé, Isabelle

    2016-07-15

    In the adult brain, structural plasticity allowing gain or loss of synapses remodels circuits to support learning. In fragile X syndrome, the absence of fragile X mental retardation protein (FMRP) leads to defects in plasticity and learning deficits. FMRP is a master regulator of local translation but its implication in learning-induced structural plasticity is unknown. Using an olfactory learning task requiring adult-born olfactory bulb neurons and cell-specific ablation of FMRP, we investigated whether learning shapes adult-born neuron morphology during their synaptic integration and its dependence on FMRP. We used alpha subunit of the calcium/calmodulin-dependent kinase II (αCaMKII) mutant mice with altered dendritic localization of αCaMKII messenger RNA, as well as a reporter of αCaMKII local translation to investigate the role of this FMRP messenger RNA target in learning-dependent structural plasticity. Learning induces profound changes in dendritic architecture and spine morphology of adult-born neurons that are prevented by ablation of FMRP in adult-born neurons and rescued by an metabotropic glutamate receptor 5 antagonist. Moreover, dendritically translated αCaMKII is necessary for learning and associated structural modifications and learning triggers an FMRP-dependent increase of αCaMKII dendritic translation in adult-born neurons. Our results strongly suggest that FMRP mediates structural plasticity of olfactory bulb adult-born neurons to support olfactory learning through αCaMKII local translation. This reveals a new role for FMRP-regulated dendritic local translation in learning-induced structural plasticity. This might be of clinical relevance for the understanding of critical periods disruption in autism spectrum disorder patients, among which fragile X syndrome is the primary monogenic cause. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  13. A light-stimulated synaptic transistor with synaptic plasticity and memory functions based on InGaZnO_x–Al_2O_3 thin film structure

    International Nuclear Information System (INIS)

    Li, H. K.; Chen, T. P.; Liu, P.; Zhang, Q.; Hu, S. G.; Liu, Y.; Lee, P. S.

    2016-01-01

    In this work, a synaptic transistor based on the indium gallium zinc oxide (IGZO)–aluminum oxide (Al_2O_3) thin film structure, which uses ultraviolet (UV) light pulses as the pre-synaptic stimulus, has been demonstrated. The synaptic transistor exhibits the behavior of synaptic plasticity like the paired-pulse facilitation. In addition, it also shows the brain's memory behaviors including the transition from short-term memory to long-term memory and the Ebbinghaus forgetting curve. The synapse-like behavior and memory behaviors of the transistor are due to the trapping and detrapping processes of the holes, which are generated by the UV pulses, at the IGZO/Al_2O_3 interface and/or in the Al_2O_3 layer.

  14. Learning to learn - intrinsic plasticity as a metaplasticity mechanism for memory formation.

    Science.gov (United States)

    Sehgal, Megha; Song, Chenghui; Ehlers, Vanessa L; Moyer, James R

    2013-10-01

    "Use it or lose it" is a popular adage often associated with use-dependent enhancement of cognitive abilities. Much research has focused on understanding exactly how the brain changes as a function of experience. Such experience-dependent plasticity involves both structural and functional alterations that contribute to adaptive behaviors, such as learning and memory, as well as maladaptive behaviors, including anxiety disorders, phobias, and posttraumatic stress disorder. With the advancing age of our population, understanding how use-dependent plasticity changes across the lifespan may also help to promote healthy brain aging. A common misconception is that such experience-dependent plasticity (e.g., associative learning) is synonymous with synaptic plasticity. Other forms of plasticity also play a critical role in shaping adaptive changes within the nervous system, including intrinsic plasticity - a change in the intrinsic excitability of a neuron. Intrinsic plasticity can result from a change in the number, distribution or activity of various ion channels located throughout the neuron. Here, we review evidence that intrinsic plasticity is an important and evolutionarily conserved neural correlate of learning. Intrinsic plasticity acts as a metaplasticity mechanism by lowering the threshold for synaptic changes. Thus, learning-related intrinsic changes can facilitate future synaptic plasticity and learning. Such intrinsic changes can impact the allocation of a memory trace within a brain structure, and when compromised, can contribute to cognitive decline during the aging process. This unique role of intrinsic excitability can provide insight into how memories are formed and, more interestingly, how neurons that participate in a memory trace are selected. Most importantly, modulation of intrinsic excitability can allow for regulation of learning ability - this can prevent or provide treatment for cognitive decline not only in patients with clinical disorders but

  15. Learning to learn – intrinsic plasticity as a metaplasticity mechanism for memory formation

    Science.gov (United States)

    Sehgal, Megha; Song, Chenghui; Ehlers, Vanessa L.; Moyer, James R.

    2013-01-01

    “Use it or lose it” is a popular adage often associated with use-dependent enhancement of cognitive abilities. Much research has focused on understanding exactly how the brain changes as a function of experience. Such experience-dependent plasticity involves both structural and functional alterations that contribute to adaptive behaviors, such as learning and memory, as well as maladaptive behaviors, including anxiety disorders, phobias, and posttraumatic stress disorder. With the advancing age of our population, understanding how use-dependent plasticity changes across the lifespan may also help to promote healthy brain aging. A common misconception is that such experience-dependent plasticity (e.g., associative learning) is synonymous with synaptic plasticity. Other forms of plasticity also play a critical role in shaping adaptive changes within the nervous system, including intrinsic plasticity – a change in the intrinsic excitability of a neuron. Intrinsic plasticity can result from a change in the number, distribution or activity of various ion channels located throughout the neuron. Here, we review evidence that intrinsic plasticity is an important and evolutionarily conserved neural correlate of learning. Intrinsic plasticity acts as a metaplasticity mechanism by lowering the threshold for synaptic changes. Thus, learning-related intrinsic changes can facilitate future synaptic plasticity and learning. Such intrinsic changes can impact the allocation of a memory trace within a brain structure, and when compromised, can contribute to cognitive decline during the aging process. This unique role of intrinsic excitability can provide insight into how memories are formed and, more interestingly, how neurons that participate in a memory trace are selected. Most importantly, modulation of intrinsic excitability can allow for regulation of learning ability – this can prevent or provide treatment for cognitive decline not only in patients with clinical

  16. Effects of bursting dynamic features on the generation of multi-clustered structure of neural network with symmetric spike-timing-dependent plasticity learning rule

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui; Song, Yongduan; Xue, Fangzheng; Li, Xiumin, E-mail: xmli@cqu.edu.cn [Key Laboratory of Dependable Service Computing in Cyber Physical Society of Ministry of Education, Chongqing University, Chongqing 400044 (China); College of Automation, Chongqing University, Chongqing 400044 (China)

    2015-11-15

    In this paper, the generation of multi-clustered structure of self-organized neural network with different neuronal firing patterns, i.e., bursting or spiking, has been investigated. The initially all-to-all-connected spiking neural network or bursting neural network can be self-organized into clustered structure through the symmetric spike-timing-dependent plasticity learning for both bursting and spiking neurons. However, the time consumption of this clustering procedure of the burst-based self-organized neural network (BSON) is much shorter than the spike-based self-organized neural network (SSON). Our results show that the BSON network has more obvious small-world properties, i.e., higher clustering coefficient and smaller shortest path length than the SSON network. Also, the results of larger structure entropy and activity entropy of the BSON network demonstrate that this network has higher topological complexity and dynamical diversity, which benefits for enhancing information transmission of neural circuits. Hence, we conclude that the burst firing can significantly enhance the efficiency of clustering procedure and the emergent clustered structure renders the whole network more synchronous and therefore more sensitive to weak input. This result is further confirmed from its improved performance on stochastic resonance. Therefore, we believe that the multi-clustered neural network which self-organized from the bursting dynamics has high efficiency in information processing.

  17. Effects of bursting dynamic features on the generation of multi-clustered structure of neural network with symmetric spike-timing-dependent plasticity learning rule

    International Nuclear Information System (INIS)

    Liu, Hui; Song, Yongduan; Xue, Fangzheng; Li, Xiumin

    2015-01-01

    In this paper, the generation of multi-clustered structure of self-organized neural network with different neuronal firing patterns, i.e., bursting or spiking, has been investigated. The initially all-to-all-connected spiking neural network or bursting neural network can be self-organized into clustered structure through the symmetric spike-timing-dependent plasticity learning for both bursting and spiking neurons. However, the time consumption of this clustering procedure of the burst-based self-organized neural network (BSON) is much shorter than the spike-based self-organized neural network (SSON). Our results show that the BSON network has more obvious small-world properties, i.e., higher clustering coefficient and smaller shortest path length than the SSON network. Also, the results of larger structure entropy and activity entropy of the BSON network demonstrate that this network has higher topological complexity and dynamical diversity, which benefits for enhancing information transmission of neural circuits. Hence, we conclude that the burst firing can significantly enhance the efficiency of clustering procedure and the emergent clustered structure renders the whole network more synchronous and therefore more sensitive to weak input. This result is further confirmed from its improved performance on stochastic resonance. Therefore, we believe that the multi-clustered neural network which self-organized from the bursting dynamics has high efficiency in information processing

  18. Plastic scintillator

    International Nuclear Information System (INIS)

    Andreeshchev, E.A.; Kilin, S.F.; Kavyrzina, K.A.

    1978-01-01

    A plastic scintillator for ionizing radiation detectors with high time resolution is suggested. To decrease the scintillation pulse width and to maintain a high light yield, the 4 1 , 4 5 -dibromo-2 1 , 2 5 , 5 1 , 5 5 -tetramethyl-n-quinquiphenyl (Br 2 Me 4 Ph) in combination with n-terphenyl (Ph 3 ) or 2, 5-diphenyloxadiazol-1, 3, 4 (PPD) is used as a luminescent addition. Taking into consideration the results of a special study, it is shown, that the following ratio of ingradients is the optimum one: 3-4 mass% Ph 3 or 4-7 mas% PPD + 2-5 mass% Br 2 Me 4 Ph + + polymeric base. The suggested scintillator on the basis of polystyrene has the light yield of 0.23-0.26 arbitrary units and the scintillation pulse duration at half-height is 0.74-0.84 ns

  19. Effect of heat treatment and plastic deformation on the structure and the mechanical properties of nitrogen-bearing 04N9Kh2A steel

    Science.gov (United States)

    Blinov, V. M.; Bannykh, O. A.; Lukin, E. I.; Kostina, M. V.; Blinov, E. V.

    2014-11-01

    The effect of the conditions of heat treatment and plastic deformation on the structure and the mechanical properties of low-carbon martensitic nickel steel (9 wt % Ni) with an overequilibrium nitrogen content is studied. The limiting strain to failure of 04N9Kh2A steel is found to be 40% at a rolling temperature of 20°C and 80% at a rolling temperature of 900°C. Significant strengthening of the steel (σ0.2 = 1089 MPa) is obtained after rolling at a reduction of 40% at 20°C. The start and final temperatures of the α → γ transformation on heating and those of the γ → α transformation on cooling are determined by dilatometry. The specific features of the formation of the steel structure have been revealed as functions of the annealing and tempering temperatures. Electron-microscopic studies show that, after quenching from 850°C and tempering at 600°C for 1 h, the structure contains packet martensite with thin interlayers of retained austenite between martensite crystals. The strength of the nitrogen-bearing 04N9Kh2A steel after quenching from 850 and 900°C, cooling in water, and subsequent tempering at 500°C for 1 h is significantly higher than that of carboncontaining 0H9 steel used in cryogenic engineering.

  20. From Lobster Shells to Plastic Objects: A Bioplastics Activity

    Science.gov (United States)

    Hudson, Reuben; Glaisher, Samuel; Bishop, Alexandra; Katz, Jeffrey L.

    2015-01-01

    A multiple day activity for students to create large-scale plastic objects from the biopolymer chitin (major component of lobster, crab, and shrimp shells) is described. The plastic objects created are durable and made from benign materials, making them suitable for students to take home to play with. Since the student-created plastic objects are…

  1. Cholinergic Potentiation and Audiovisual Repetition-Imitation Therapy Improve Speech Production and Communication Deficits in a Person with Crossed Aphasia by Inducing Structural Plasticity in White Matter Tracts

    Directory of Open Access Journals (Sweden)

    Marcelo L. Berthier

    2017-06-01

    Full Text Available Donepezil (DP, a cognitive-enhancing drug targeting the cholinergic system, combined with massed sentence repetition training augmented and speeded up recovery of speech production deficits in patients with chronic conduction aphasia and extensive left hemisphere infarctions (Berthier et al., 2014. Nevertheless, a still unsettled question is whether such improvements correlate with restorative structural changes in gray matter and white matter pathways mediating speech production. In the present study, we used pharmacological magnetic resonance imaging to study treatment-induced brain changes in gray matter and white matter tracts in a right-handed male with chronic conduction aphasia and a right subcortical lesion (crossed aphasia. A single-patient, open-label multiple-baseline design incorporating two different treatments and two post-treatment evaluations was used. The patient received an initial dose of DP (5 mg/day which was maintained during 4 weeks and then titrated up to 10 mg/day and administered alone (without aphasia therapy during 8 weeks (Endpoint 1. Thereafter, the drug was combined with an audiovisual repetition-imitation therapy (Look-Listen-Repeat, LLR during 3 months (Endpoint 2. Language evaluations, diffusion weighted imaging (DWI, and voxel-based morphometry (VBM were performed at baseline and at both endpoints in JAM and once in 21 healthy control males. Treatment with DP alone and combined with LLR therapy induced marked improvement in aphasia and communication deficits as well as in selected measures of connected speech production, and phrase repetition. The obtained gains in speech production remained well-above baseline scores even 4 months after ending combined therapy. Longitudinal DWI showed structural plasticity in the right frontal aslant tract and direct segment of the arcuate fasciculus with both interventions. VBM revealed no structural changes in other white matter tracts nor in cortical areas linked by these

  2. Combined motor cortex and spinal cord neuromodulation promotes corticospinal system functional and structural plasticity and motor function after injury.

    Science.gov (United States)

    Song, Weiguo; Amer, Alzahraa; Ryan, Daniel; Martin, John H

    2016-03-01

    An important strategy for promoting voluntary movements after motor system injury is to harness activity-dependent corticospinal tract (CST) plasticity. We combine forelimb motor cortex (M1) activation with co-activation of its cervical spinal targets in rats to promote CST sprouting and skilled limb movement after pyramidal tract lesion (PTX). We used a two-step experimental design in which we first established the optimal combined stimulation protocol in intact rats and then used the optimal protocol in injured animals to promote CST repair and motor recovery. M1 was activated epidurally using an electrical analog of intermittent theta burst stimulation (iTBS). The cervical spinal cord was co-activated by trans-spinal direct current stimulation (tsDCS) that was targeted to the cervical enlargement, simulated from finite element method. In intact rats, forelimb motor evoked potentials (MEPs) were strongly facilitated during iTBS and for 10 min after cessation of stimulation. Cathodal, not anodal, tsDCS alone facilitated MEPs and also produced a facilitatory aftereffect that peaked at 10 min. Combined iTBS and cathodal tsDCS (c-tsDCS) produced further MEP enhancement during stimulation, but without further aftereffect enhancement. Correlations between forelimb M1 local field potentials and forelimb electromyogram (EMG) during locomotion increased after electrical iTBS alone and further increased with combined stimulation (iTBS+c-tsDCS). This optimized combined stimulation was then used to promote function after PTX because it enhanced functional connections between M1 and spinal circuits and greater M1 engagement in muscle contraction than either stimulation alone. Daily application of combined M1 iTBS on the intact side and c-tsDCS after PTX (10 days, 27 min/day) significantly restored skilled movements during horizontal ladder walking. Stimulation produced a 5.4-fold increase in spared ipsilateral CST terminations. Combined neuromodulation achieves optimal motor

  3. Toxicological Threats of Plastic

    Science.gov (United States)

    Plastics pose both physical (e.g., entanglement, gastrointestinal blockage, reef destruction) and chemical threats (e.g., bioaccumulation of the chemical ingredients of plastic or toxic chemicals sorbed to plastics) to wildlife and the marine ecosystem.

  4. Synaptic plasticity in drug reward circuitry.

    Science.gov (United States)

    Winder, Danny G; Egli, Regula E; Schramm, Nicole L; Matthews, Robert T

    2002-11-01

    Drug addiction is a major public health issue worldwide. The persistence of drug craving coupled with the known recruitment of learning and memory centers in the brain has led investigators to hypothesize that the alterations in glutamatergic synaptic efficacy brought on by synaptic plasticity may play key roles in the addiction process. Here we review the present literature, examining the properties of synaptic plasticity within drug reward circuitry, and the effects that drugs of abuse have on these forms of plasticity. Interestingly, multiple forms of synaptic plasticity can be induced at glutamatergic synapses within the dorsal striatum, its ventral extension the nucleus accumbens, and the ventral tegmental area, and at least some of these forms of plasticity are regulated by behaviorally meaningful administration of cocaine and/or amphetamine. Thus, the present data suggest that regulation of synaptic plasticity in reward circuits is a tractable candidate mechanism underlying aspects of addiction.

  5. Crack Detection in Fibre Reinforced Plastic Structures Using Embedded Fibre Bragg Grating Sensors: Theory, Model Development and Experimental Validation

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    properties. When applying this concept to different structures, sensor systems and damage types, a combination of damage mechanics, monitoring technology, and modelling is required. The primary objective of this article is to demonstrate such a combination. This article is divided in three main topics......: the damage mechanism (delamination of FRP), the structural health monitoring technology (fibre Bragg gratings to detect delamination), and the finite element method model of the structure that incorporates these concepts into a final and integrated damage-monitoring concept. A novel method for assessing...... by the end-user. Conjointly, a novel model for sensor output prediction (virtual sensor) was developed using this FBG sensor crack monitoring concept and implemented in a finite element method code. The monitoring method was demonstrated and validated using glass fibre double cantilever beam specimens...

  6. The effects of gestational stress and SSRI antidepressant treatment on structural plasticity in the postpartum brain - a translational model for postpartum depression

    Science.gov (United States)

    Haim, Achikam; Albin-Brooks, Christopher; Sherer, Morgan; Mills, Emily; Leuner, Benedetta

    2015-01-01

    Postpartum depression (PPD) is a common complication following childbirth experienced by one in every five new mothers. Although the neural basis of PPD remains unknown previous research in rats has shown that gestational stress, a risk factor for PPD, induces depressive-like behavior during the postpartum period. Moreover, the effect of gestational stress on postpartum mood is accompanied by structural modifications within the nucleus accumbens (NAc) and the medial prefrontal cortex (mPFC) – limbic regions that have been linked to PPD. Mothers diagnosed with PPD are often prescribed selective serotonin reuptake inhibitor (SSRI) antidepressant medications and yet little is known about their effects in models of PPD. Thus, here we investigated whether postpartum administration of Citalopram, an SSRI commonly used to treat PPD, would ameliorate the behavioral and morphological consequences of gestational stress. In addition, we examined the effects of gestational stress and postpartum administration of Citalopram on structural plasticity within the basolateral amygdala (BLA) which together with the mPFC and NAc forms a circuit that is sensitive to stress and is involved in mood regulation. Our results show that postpartum rats treated with Citalopram do not exhibit gestational stress-induced depressive-like behavior in the forced swim test. In addition, Citalopram was effective in reversing gestational stress-induced structural alterations in the postpartum NAc shell and mPFC. We also found that gestational stress increased spine density within the postpartum BLA, an effect which was not reversed by Citalopram treatment. Overall, these data highlight the usefulness of gestational stress as a valid and informative translational model for PPD. Furthermore, they suggest that structural alterations in the mPFC-NAc pathway may underlie stress-induced depressive-like behavior during the postpartum period and provide much needed information on how SSRIs may act in the

  7. A peptide mimetic targeting trans-homophilic NCAM binding sites promotes spatial learning and neural plasticity in the hippocampus

    DEFF Research Database (Denmark)

    Kraev, Igor; Henneberger, Christian; Rossetti, Clara

    2011-01-01

    The key roles played by the neural cell adhesion molecule (NCAM) in plasticity and cognition underscore this membrane protein as a relevant target to develop cognitive-enhancing drugs. However, NCAM is a structurally and functionally complex molecule with multiple domains engaged in a variety of ...

  8. The Neural Cell Adhesion Molecule-Derived Peptide FGL Facilitates Long-Term Plasticity in the Dentate Gyrus in Vivo

    Science.gov (United States)

    Dallerac, Glenn; Zerwas, Meike; Novikova, Tatiana; Callu, Delphine; Leblanc-Veyrac, Pascale; Bock, Elisabeth; Berezin, Vladimir; Rampon, Claire; Doyere, Valerie

    2011-01-01

    The neural cell adhesion molecule (NCAM) is known to play a role in developmental and structural processes but also in synaptic plasticity and memory of the adult animal. Recently, FGL, a NCAM mimetic peptide that binds to the Fibroblast Growth Factor Receptor 1 (FGFR-1), has been shown to have a beneficial impact on normal memory functioning, as…

  9. Compensatory plasticity: time matters

    Directory of Open Access Journals (Sweden)

    Latifa eLazzouni

    2014-06-01

    Full Text Available Plasticity in the human and animal brain is the rule, the base for development, and the way to deal effectively with the environment for making the most efficient use of all the senses. When the brain is deprived of one sensory modality, plasticity becomes compensatory: the exception that invalidates the general loss hypothesis giving the opportunity of effective change. Sensory deprivation comes with massive alterations in brain structure and function, behavioural outcomes, and neural interactions. Blind individuals do as good as the sighted and even more, show superior abilities in auditory, tactile and olfactory processing. This behavioural enhancement is accompanied with changes in occipital cortex function, where visual areas at different levels become responsive to non-visual information. The intact senses are in general used more efficiently in the blind but are also used more exclusively. New findings are disentangling these two aspects of compensatory plasticity. What is due to visual deprivation and what is dependent on the extended use of spared modalities? The latter seems to contribute highly to compensatory changes in the congenitally blind. Short term deprivation through the use of blindfolds shows that cortical excitability of the visual cortex is likely to show rapid modulatory changes after few minutes of light deprivation and therefore changes are possible in adulthood. However, reorganization remains more pronounced in the congenitally blind. Cortico-cortical pathways between visual areas and the areas of preserved sensory modalities are inhibited in the presence of vision, but are unmasked after loss of vision or blindfolding as a mechanism likely to drive cross-modal information to the deafferented visual cortex. Plasticity in the blind is also accompanied with neurochemical and morphological changes; both intrinsic connectivity and functional coupling at rest are altered but are likewise dependent on different sensory

  10. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  11. Designing Out the Play: Accessibility and Playfulness in Inclusive Play.

    Science.gov (United States)

    Holt, Raymond; Beckett, Angharad

    2017-01-01

    Play is an important part of child development, yet disabled children are often excluded from the opportunity to play, either due to lack of accessible toys and games, or social pressures. This paper presents a case study reflecting on the development of Button Bash: a switch accessible game intended to encourage inclusive play between disabled and non-disabled children. In particular, the paper focuses on how changes intended to make the game more accessible tended to make it less playful, and reflects on the relationship between playfulness and accessibility.

  12. Effect of ethylene carbonate as a plasticizer on CuI/PVA nanocomposite: Structure, optical and electrical properties

    Directory of Open Access Journals (Sweden)

    Shaimaa A. Mohamed

    2014-01-01

    Full Text Available Layers of ethylene carbonate (EC modified CuI/PVA polymer composites were prepared by growth of CuI nano-particles in an aqueous solution of PVA followed by casting at room temperature. The structural, thermal, optical, electrical and di-electrical characterization of polymer composites was investigated using different techniques. These investigations confirm the growth of CuI nano-particles and reduction of PVA crystallinity by increasing ethylene carbonate concentration. These results show that energy band gap and bulk conductivity increase while activation energy reduces with the increase of EC concentration in the composite. Moreover, the variation of the dielectric permittivity and dielectric loss with EC content are found to obey Debye dispersion relations.

  13. Microstructure, plastic deformation and strengthening mechanisms of an Al–Mg–Si alloy with a bimodal grain structure

    International Nuclear Information System (INIS)

    Shakoori Oskooie, M.; Asgharzadeh, H.; Kim, H.S.

    2015-01-01

    Highlights: • Al6063 with bimodal grain structures was fabricated by a powder metallurgy route. • The bimodal alloys showed a reasonable ductility together with a high strength. • Grain boundary strengthening was reduced at higher fraction of coarse grains. • The enhanced tensile ductility was attributed to crack blunting and delamination. - Abstract: Al6063 alloys with bimodal grain size distributions comprised of ultrafine-grained (UFG) and coarse-grained (CG) regions were produced via mechanical milling followed by hot extrusion. High-energy planetary ball milling for 22.5 h with a rotational speed of 350 rpm was employed for the synthesis of nanocrystalline Al6063 powders. The as-milled Al6063 powders were mixed with 15, 30, and 45 vol.% of the unmilled powders and then the powder mixtures were consolidated via extrusion at 450 °C with an extrusion ratio of 9:1. The microstructure of the bimodal extrudates was investigated using optical microscope, transmission electron microscope (TEM) and field emission scanning electron microscope equipped with an electron backscattered diffraction (EBSD) detector. The deformation behavior was investigated by means of uniaxial tensile tests. The bimodal Al6063 exhibited balanced mechanical properties, including high yield stress and ultimate tensile strength resulting from the UFG regions together with reasonable ductility attained from the CG areas. The fracture surfaces demonstrated a ductile fracture mode, in which the dimple size was correlated with the grain structure. The strengthening mechanisms are discussed based on the dislocation models and the functions of the CGs in the deformation behavior and ductility enhancement of bimodal Al6063 are explored

  14. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like...

  15. Structural plasticity of remote cortical brain regions is determined by connectivity to the primary lesion in subcortical stroke.

    Science.gov (United States)

    Cheng, Bastian; Schulz, Robert; Bönstrup, Marlene; Hummel, Friedhelm C; Sedlacik, Jan; Fiehler, Jens; Gerloff, Christian; Thomalla, Götz

    2015-09-01

    Cortical atrophy as demonstrated by measurement of cortical thickness (CT) is a hallmark of various neurodegenerative diseases. In the wake of an acute ischemic stroke, brain architecture undergoes dynamic changes that can be tracked by structural and functional magnetic resonance imaging studies as soon as 3 months after stroke. In this study, we measured changes of CT in cortical areas connected to subcortical stroke lesions in 12 patients with upper extremity paresis combining white-matter tractography and semi-automatic measurement of CT using the Freesurfer software. Three months after stroke, a significant decrease in CT of -2.6% (median, upper/lower boundary of 95% confidence interval -4.1%/-1.1%) was detected in areas connected to ischemic lesions, whereas CT in unconnected cortical areas remained largely unchanged. A cluster of significant cortical thinning was detected in the superior frontal gyrus of the stroke hemisphere using a surface-based general linear model correcting for multiple comparisons. There was no significant correlation of changes in CT with clinical outcome parameters. Our results show a specific impact of subcortical lesions on distant, yet connected cortical areas explainable by secondary neuro-axonal degeneration of distant areas.

  16. Introduction to Computational Plasticity

    International Nuclear Information System (INIS)

    Hartley, P

    2006-01-01

    The focus of the book on computational plasticity embodies techniques of relevance not only to academic researchers, but also of interest to industrialists engaged in the production of components using bulk or sheet forming processes. Of particular interest is the guidance on how to create modules for use with the commercial system Abaqus for specific types of material behaviour. The book is in two parts, the first of which contains six chapters, starting with microplasticity, but predominantly on continuum plasticity. The first chapter on microplasticty gives a brief description of the grain structure of metals and the existence of slip systems within the grains. This provides an introduction to the concept of incompressibility during plastic deformation, the nature of plastic yield and the importance of the critically resolved shear stress on the slip planes (Schmid's law). Some knowledge of the notation commonly used to describe slip systems is assumed, which will be familiar to students of metallurgy, but anyone with a more general engineering background may need to undertake additional reading to understand the various descriptions. Chapter two introduces one of several yield criteria, that normally attributed to von Mises (though historians of mechanics might argue over who was first to develop the theory of yielding associated with strain energy density), and its two or three-dimensional representation as a yield surface. The expansion of the yield surface during plastic deformation, its translation due to kinematic hardening and the Bauschinger effect in reversed loading are described with a direct link to the material stress-strain curve. The assumption, that the increment of strain is normal to the yield surface, the normality principle, is introduced. Uniaxial loading of an elastic-plastic material is used as an example in which to develop expressions to describe increments in stress and strain. The full presentation of numerous expressions, tensors and

  17. Identifying Structure-Property Relationships Through DREAM.3D Representative Volume Elements and DAMASK Crystal Plasticity Simulations: An Integrated Computational Materials Engineering Approach

    Science.gov (United States)

    Diehl, Martin; Groeber, Michael; Haase, Christian; Molodov, Dmitri A.; Roters, Franz; Raabe, Dierk

    2017-05-01

    Predicting, understanding, and controlling the mechanical behavior is the most important task when designing structural materials. Modern alloy systems—in which multiple deformation mechanisms, phases, and defects are introduced to overcome the inverse strength-ductility relationship—give raise to multiple possibilities for modifying the deformation behavior, rendering traditional, exclusively experimentally-based alloy development workflows inappropriate. For fast and efficient alloy design, it is therefore desirable to predict the mechanical performance of candidate alloys by simulation studies to replace time- and resource-consuming mechanical tests. Simulation tools suitable for this task need to correctly predict the mechanical behavior in dependence of alloy composition, microstructure, texture, phase fractions, and processing history. Here, an integrated computational materials engineering approach based on the open source software packages DREAM.3D and DAMASK (Düsseldorf Advanced Materials Simulation Kit) that enables such virtual material development is presented. More specific, our approach consists of the following three steps: (1) acquire statistical quantities that describe a microstructure, (2) build a representative volume element based on these quantities employing DREAM.3D, and (3) evaluate the representative volume using a predictive crystal plasticity material model provided by DAMASK. Exemplarily, these steps are here conducted for a high-manganese steel.

  18. Cognitive structure, flexibility, and plasticity in human multitasking-An integrative review of dual-task and task-switching research.

    Science.gov (United States)

    Koch, Iring; Poljac, Edita; Müller, Hermann; Kiesel, Andrea

    2018-06-01

    Numerous studies showed decreased performance in situations that require multiple tasks or actions relative to appropriate control conditions. Because humans often engage in such multitasking activities, it is important to understand how multitasking affects performance. In the present article, we argue that research on dual-task interference and sequential task switching has proceeded largely separately using different experimental paradigms and methodology. In our article we aim at organizing this complex set of research in terms of three complementary research perspectives on human multitasking. One perspective refers to structural accounts in terms of cognitive bottlenecks (i.e., critical processing stages). A second perspective refers to cognitive flexibility in terms of the underlying cognitive control processes. A third perspective emphasizes cognitive plasticity in terms of the influence of practice on human multitasking abilities. With our review article we aimed at highlighting the value of an integrative position that goes beyond isolated consideration of a single theoretical research perspective and that broadens the focus from single experimental paradigms (dual task and task switching) to favor instead a view that emphasizes the fundamental similarity of the underlying cognitive mechanisms across multitasking paradigms. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  19. Self-organization in Balanced State Networks by STDP and Homeostatic Plasticity.

    Directory of Open Access Journals (Sweden)

    Felix Effenberger

    2015-09-01

    Full Text Available Structural inhomogeneities in synaptic efficacies have a strong impact on population response dynamics of cortical networks and are believed to play an important role in their functioning. However, little is known about how such inhomogeneities could evolve by means of synaptic plasticity. Here we present an adaptive model of a balanced neuronal network that combines two different types of plasticity, STDP and synaptic scaling. The plasticity rules yield both long-tailed distributions of synaptic weights and firing rates. Simultaneously, a highly connected subnetwork of driver neurons with strong synapses emerges. Coincident spiking activity of several driver cells can evoke population bursts and driver cells have similar dynamical properties as leader neurons found experimentally. Our model allows us to observe the delicate interplay between structural and dynamical properties of the emergent inhomogeneities. It is simple, robust to parameter changes and able to explain a multitude of different experimental findings in one basic network.

  20. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  1. Three-legged platform in a plastic limit state

    Energy Technology Data Exchange (ETDEWEB)

    Lagoni, P

    1990-06-01

    This document provides structural description, formulars and a sample analysis of a platform supported by three piles and subject to loads that causes plastic deformation of the foundation (plastic limit state analysis). (au)

  2. Long-term fluoxetine treatment induces input-specific LTP and LTD impairment and structural plasticity in the CA1 hippocampal subfield.

    Directory of Open Access Journals (Sweden)

    Francisco J Rubio

    2013-05-01

    Full Text Available Antidepressant drugs are usually administered for long time for the treatment of major depressive disorder. However, they are also prescribed in several additional psychiatric conditions as well as during long term maintenance treatments. Antidepressants induce adaptive changes in several forebrain structures which include modifications at glutamatergic synapses. We recently found that repetitive administration of the selective serotonin reuptake inhibitor fluoxetine to naϊve adult male rats induced an increase of mature, mushroom-type dendritic spines in several forebrain regions. This was associated with an increase of GluA2-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPA-Rs in telencephalic postsynaptic densities. To unravel the functional significance of such a synaptic re-arrangement, we focused on glutamate neurotransmission in the hippocampus. We evaluated the effect of four weeks of treatment with 0.7 mg/kg of fluoxetine on long-term potentiation (LTP and long-term depression (LTD in the Schaffer collateral-CA1 synapses and the perforant path-CA1 synapses. Recordings in hippocampal slices revealed profound deficits in LTP and LTD at Schaffer collateral-CA1 synapses associated to increased spine density and enhanced presence of mushroom-type spines, as revealed by Golgi staining. However, the same treatment had neither an effect on spine morphology, nor on LTP and LTD at perforant path-CA1 synapses. Cobalt staining experiments revealed decreased AMPA-R Ca2+ permeability in the stratum radiatum together with increased GluA2-containing, Ca2+-impermeable AMPA-Rs. Therefore, 4 weeks of fluoxetine treatment promoted structural and functional adaptations in CA1 neurons in a pathway-specific manner that were selectively associated with impairment of activity-dependent plasticity at Schaffer collateral-CA1 synapses.

  3. Collagen type XI alpha1 may be involved in the structural plasticity of the vertebral column in Atlantic salmon (Salmo salar L.).

    Science.gov (United States)

    Wargelius, A; Fjelldal, P G; Nordgarden, U; Grini, A; Krossøy, C; Grotmol, S; Totland, G K; Hansen, T

    2010-04-01

    Atlantic salmon (Salmo salar L.) vertebral bone displays plasticity in structure, osteoid secretion and mineralization in response to photoperiod. Other properties of the vertebral bone, such as mineral content and mechanical strength, are also associated with common malformations in farmed Atlantic salmon. The biological mechanisms that underlie these changes in bone physiology are unknown, and in order to elucidate which factors might be involved in this process, microarray assays were performed on vertebral bone of Atlantic salmon reared under natural or continuous light. Eight genes were upregulated in response to continuous light treatment, whereas only one of them was upregulated in a duplicate experiment. The transcriptionally regulated gene was predicted to code for collagen type XI alpha1, a protein known to be involved in controlling the diameter of fibrillar collagens in mammals. Furthermore, the gene was highly expressed in the vertebrae, where spatial expression was found in trabecular and compact bone osteoblasts and in the chordoblasts of the notochordal sheath. When we measured the expression level of the gene in the tissue compartments of the vertebrae, the collagen turned out to be 150 and 25 times more highly expressed in the notochord and compact bone respectively, relative to the expression in the trabecular bone. Gene expression was induced in response to continuous light, and reduced in compressed vertebrae. The downregulation in compressed vertebrae was due to reduced expression in the compact bone, while expression in the trabecular bone and the notochord was unaffected. These data support the hypothesis that this gene codes for a presumptive collagen type XI alpha1, which may be involved in the regulatory pathway leading to structural adaptation of the vertebral architecture.

  4. A review of plastic waste biodegradation.

    Science.gov (United States)

    Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

    2005-01-01

    With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.

  5. Stacking fault tetrahedron induced plasticity in copper single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liang, E-mail: lz592@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Lu, Cheng, E-mail: chenglu@uow.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Tieu, Kiet; Su, Lihong; Zhao, Xing [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Pei, Linqing [Department of Mechanical Engineering, Chongqing University, Chongqing 400044 (China)

    2017-01-05

    Stacking fault tetrahedron (SFT) is the most common type of vacancy clustered defects in fcc metals and alloys, and can play an important role in the mechanical properties of metallic materials. In this study, molecular dynamics (MD) simulations were carried out to investigate the incipience of plasticity and the underlying atomic mechanisms in copper single crystals with SFT. Different deformation mechanisms of SFT were reported due to the crystal orientations and loading directions (compression and tension). The results showed that the incipient plasticity in crystals with SFT resulted from the heterogeneous dislocation nucleation from SFT, so the stress required for plastic deformation was less than that needed for perfect single crystals. Three crystal orientations ([1 0 0], [1 1 0] and [1 1 1]) were specified in this study because they can represent most of the typical deformation mechanisms of SFT. MD simulations revealed that the structural transformation of SFT was frequent under the applied loading; a metastable SFT structure and the collapse of SFT were usually observed. The structural transformation resulted in a different reduction of yield stress in compression and tension, and also caused a decreased or reversed compression/tension asymmetry. Compressive stress can result in the unfaulting of Frank loop in some crystal orientations. According to the elastic theory of dislocation, the process of unfaulting was closely related to the size of the dislocation loop and the stacking fault energy.

  6. Studies of elastic-plastic instabilities

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1999-01-01

    Analyses of plastic instabilities are reviewed, with focus on results in structural mechanics as well as continuum mechanics. First the basic theories for bifurcation and post-bifurcation behavior are briefly presented. Then, localization of plastic flow is discussed, including shear band formati...

  7. Play Therapy: A Review

    Science.gov (United States)

    Porter, Maggie L.; Hernandez-Reif, Maria; Jessee, Peggy

    2009-01-01

    This article discusses the current issues in play therapy and its implications for play therapists. A brief history of play therapy is provided along with the current play therapy approaches and techniques. This article also touches on current issues or problems that play therapists may face, such as interpreting children's play, implementing…

  8. Plastic deformation of 2D crumpled wires

    International Nuclear Information System (INIS)

    Gomes, M A F; Donato, C C; Brito, V P; Coelho, A S O

    2008-01-01

    When a single long piece of elastic wire is injected through channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper this packing process is investigated but using plastic wires which give rise to completely irreversible structures of different morphology. In particular, the plastic deformation from circular to oblate configurations of crumpled wires is experimentally studied, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility and very large deformations, scaling is still observed.

  9. Structure of Bacteroides thetaiotaomicron BT2081 at 2.05 Å resolution: the first structural representative of a new protein family that may play a role in carbohydrate metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Andrew P. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Abdubek, Polat [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (United States); Astakhova, Tamara [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (United States); Axelrod, Herbert L. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Bakolitsa, Constantina [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA (United States); Cai, Xiaohui [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (United States); Carlton, Dennis [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (United States); Chen, Connie [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (United States); Chiu, Hsiu-Ju [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Chiu, Michelle [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (United States); Clayton, Thomas [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (United States); Das, Debanu [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Deller, Marc C. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (United States); Duan, Lian; Ellrott, Kyle [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (United States); Farr, Carol L. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (United States); Feuerhelm, Julie; Grant, Joanna C. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (United States); Grzechnik, Anna; Han, Gye Won [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (United States); Jaroszewski, Lukasz [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (United States); Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA (United States); Jin, Kevin K. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Klock, Heath E.; Knuth, Mark W. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (United States); Kozbial, Piotr [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA (United States); Krishna, S. Sri [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (United States); Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA (United States); Kumar, Abhinav; Lam, Winnie W. [Joint Center for Structural Genomics, http://www.jcsg.org (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Marciano, David [Joint Center for Structural Genomics, http://www.jcsg.org (US); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (US); McMullan, Daniel [Joint Center for Structural Genomics, http://www.jcsg.org (US); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (US); Miller, Mitchell D. [Joint Center for Structural Genomics, http://www.jcsg.org (US); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (US); Morse, Andrew T. [Joint Center for Structural Genomics, http://www.jcsg.org (US); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (US); Nigoghossian, Edward [Joint Center for Structural Genomics, http://www.jcsg.org (US); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (US); Nopakun, Amanda [Joint Center for Structural Genomics, http://www.jcsg.org (US); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (US); Okach, Linda; Puckett, Christina [Joint Center for Structural Genomics, http://www.jcsg.org (US); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (US); Reyes, Ron [Joint Center for Structural Genomics, http://www.jcsg.org (US); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (US); Tien, Henry J. [Joint Center for Structural Genomics, http://www.jcsg.org (US); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (US); Trame, Christine B.; Bedem, Henry van den [Joint Center for Structural Genomics, http://www.jcsg.org (US); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (US); Weekes, Dana [Joint Center for Structural Genomics, http://www.jcsg.org (US); Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA (US); Wooten, Tiffany [Joint Center for Structural Genomics, http://www.jcsg.org (US); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (US); Xu, Qingping [Joint Center for Structural Genomics, http://www.jcsg.org (US); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (US); Hodgson, Keith O. [Joint Center for Structural Genomics, http://www.jcsg.org (US); Photon Science, SLAC National Accelerator Laboratory, Menlo Park, CA (US); Wooley, John [Joint Center for Structural Genomics, http://www.jcsg.org (US); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (US); Elsliger, Marc-André [Joint Center for Structural Genomics, http://www.jcsg.org (US); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (US); Deacon, Ashley M. [Joint Center for Structural Genomics, http://www.jcsg.org (US); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (US); Godzik, Adam [Joint Center for Structural Genomics, http://www.jcsg.org (US); Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA (US); Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA (US); Lesley, Scott A. [Joint Center for Structural Genomics, http://www.jcsg.org (US); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA (US); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (US); Wilson, Ian A., E-mail: wilson@scripps.edu [Joint Center for Structural Genomics, http://www.jcsg.org (US); Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA (US)

    2010-10-01

    The crystal structure of BT2081 from B. thetaiotaomicron reveals a two-domain protein with a putative carbohydrate-binding site in the C-terminal domain. BT2081 from Bacteroides thetaiotaomicron (GenBank accession code NP-810994.1) is a member of a novel protein family consisting of over 160 members, most of which are found in the different classes of Bacteroidetes. Genome-context analysis lends support to the involvement of this family in carbohydrate metabolism, which plays a key role in B. thetaiotaomicron as a predominant bacterial symbiont in the human distal gut microbiome. The crystal structure of BT2081 at 2.05 Å resolution represents the first structure from this new protein family. BT2081 consists of an N-terminal domain, which adopts a β-sandwich immunoglobulin-like fold, and a larger C-terminal domain with a β-sandwich jelly-roll fold. Structural analyses reveal that both domains are similar to those found in various carbohydrate-active enzymes. The C-terminal β-jelly-roll domain contains a potential carbohydrate-binding site that is highly conserved among BT2081 homologs and is situated in the same location as the carbohydrate-binding sites that are found in structurally similar glycoside hydrolases (GHs). However, in BT2081 this site is partially occluded by surrounding loops, which results in a deep solvent-accessible pocket rather than a shallower solvent-exposed cleft.

  10. Structure of Bacteroides thetaiotaomicron BT2081 at 2.05 Å resolution: the first structural representative of a new protein family that may play a role in carbohydrate metabolism

    International Nuclear Information System (INIS)

    Yeh, Andrew P.; Abdubek, Polat; Astakhova, Tamara; Axelrod, Herbert L.; Bakolitsa, Constantina; Cai, Xiaohui; Carlton, Dennis; Chen, Connie; Chiu, Hsiu-Ju; Chiu, Michelle; Clayton, Thomas; Das, Debanu; Deller, Marc C.; Duan, Lian; Ellrott, Kyle; Farr, Carol L.; Feuerhelm, Julie; Grant, Joanna C.; Grzechnik, Anna; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K.; Klock, Heath E.; Knuth, Mark W.; Kozbial, Piotr; Krishna, S. Sri; Kumar, Abhinav; Lam, Winnie W.; Marciano, David; McMullan, Daniel; Miller, Mitchell D.; Morse, Andrew T.; Nigoghossian, Edward; Nopakun, Amanda; Okach, Linda; Puckett, Christina; Reyes, Ron; Tien, Henry J.; Trame, Christine B.; Bedem, Henry van den; Weekes, Dana; Wooten, Tiffany; Xu, Qingping; Hodgson, Keith O.; Wooley, John; Elsliger, Marc-André; Deacon, Ashley M.; Godzik, Adam; Lesley, Scott A.; Wilson, Ian A.

    2010-01-01

    The crystal structure of BT2081 from B. thetaiotaomicron reveals a two-domain protein with a putative carbohydrate-binding site in the C-terminal domain. BT2081 from Bacteroides thetaiotaomicron (GenBank accession code NP-810994.1) is a member of a novel protein family consisting of over 160 members, most of which are found in the different classes of Bacteroidetes. Genome-context analysis lends support to the involvement of this family in carbohydrate metabolism, which plays a key role in B. thetaiotaomicron as a predominant bacterial symbiont in the human distal gut microbiome. The crystal structure of BT2081 at 2.05 Å resolution represents the first structure from this new protein family. BT2081 consists of an N-terminal domain, which adopts a β-sandwich immunoglobulin-like fold, and a larger C-terminal domain with a β-sandwich jelly-roll fold. Structural analyses reveal that both domains are similar to those found in various carbohydrate-active enzymes. The C-terminal β-jelly-roll domain contains a potential carbohydrate-binding site that is highly conserved among BT2081 homologs and is situated in the same location as the carbohydrate-binding sites that are found in structurally similar glycoside hydrolases (GHs). However, in BT2081 this site is partially occluded by surrounding loops, which results in a deep solvent-accessible pocket rather than a shallower solvent-exposed cleft

  11. Entrapment and near Miss: A Comparative Analysis of Psycho-Structural Elements in Gambling Games and Massively Multiplayer Online Role-Playing Games

    Science.gov (United States)

    Karlsen, Faltin

    2011-01-01

    While massively multiplayer online role-playing games like World of Warcraft are often accused of leading to excessive and harmful playing, the only gaming activity that is internationally recognized as a pathological disorder is excessive gambling. The present article seeks to establish empirical data on potential harmful online gaming through a…

  12. Structural and Functional Plasticity within the Nucleus Accumbens and Prefrontal Cortex Associated with Time-Dependent Increases in Food Cue-Seeking Behavior.

    Science.gov (United States)

    Dingess, Paige M; Darling, Rebecca A; Derman, Rifka C; Wulff, Shaun S; Hunter, Melissa L; Ferrario, Carrie R; Brown, Travis E

    2017-11-01

    Urges to consume food can be driven by stimuli in the environment that are associated with previous food experience. Identifying adaptations within brain reward circuits that facilitate cue-induced food seeking is critical for understanding and preventing the overconsumption of food and subsequent weight gain. Utilizing electrophysiological, biochemical, and DiI labeling, we examined functional and structural changes in the nucleus accumbens (NAc) and prefrontal cortex (PFC) associated with time-dependent increases in food craving ('incubation of craving'). Rats self-administered 60% high fat or chow 45 mg pellets and were then tested for incubation of craving either 1 or 30 days after training. High fat was chosen for comparison to determine whether palatability differentially affected incubation and/or plasticity. Rats showed robust incubation of craving for both food rewards, although responding for cues previously associated with high fat was greater than chow at both 1 and 30 days. In addition, previous experience with high-fat consumption reduced dendritic spine density in the PFC at both time points. In contrast, incubation was associated with an increase in NAc spine density and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated transmission at 30 days in both groups. Finally, incubation of craving for chow and high fat was accompanied by an increase in calcium-permeable and calcium-impermeable AMPARs, respectively. Our results suggest that incubation of food craving alters brain reward circuitry and macronutrient composition specifically induces cortical changes in a way that may facilitate maladaptive food-seeking behaviors.

  13. Motor cortical plasticity in Parkinson's disease.

    Science.gov (United States)

    Udupa, Kaviraja; Chen, Robert

    2013-09-04

    In Parkinson's disease (PD), there are alterations of the basal ganglia (BG) thalamocortical networks, primarily due to degeneration of nigrostriatal dopaminergic neurons. These changes in subcortical networks lead to plastic changes in primary motor cortex (M1), which mediates cortical motor output and is a potential target for treatment of PD. Studies investigating the motor cortical plasticity using non-invasive transcranial magnetic stimulation (TMS) have found altered plasticity in PD, but there are inconsistencies among these studies. This is likely because plasticity depends on many factors such as the extent of dopaminergic loss and disease severity, response to dopaminergic replacement therapies, development of l-DOPA-induced dyskinesias (LID), the plasticity protocol used, medication, and stimulation status in patients treated with deep brain stimulation (DBS). The influences of LID and DBS on BG and M1 plasticity have been explored in animal models and in PD patients. In addition, many other factors such age, genetic factors (e.g., brain derived neurotropic factor and other neurotransmitters or receptors polymorphism), emotional state, time of the day, physical fitness have been documented to play role in the extent of plasticity induced by TMS in human studies. In this review, we summarize the studies that investigated M1 plasticity in PD and demonstrate how these afore-mentioned factors affect motor cortical plasticity in PD. We conclude that it is important to consider the clinical, demographic, and technical factors that influence various plasticity protocols while developing these protocols as diagnostic or prognostic tools in PD. We also discuss how the modulation of cortical excitability and the plasticity with these non-invasive brain stimulation techniques facilitate the understanding of the pathophysiology of PD and help design potential therapeutic possibilities in this disorder.

  14. The Prism Plastic Calorimeter (PPC)

    CERN Multimedia

    2002-01-01

    This proposal supports two goals: \\\\ \\\\ First goal:~~Demonstrate that current, widely used plastic technologies allow to design Prism Plastic Calorimeter~(PPC) towers with a new ``liquid crystal'' type plastic called Vectra. It will be shown that this technique meets the requirements for a LHC calorimeter with warm liquids: safety, hermeticity, hadronic compensation, resolution and time response. \\\\ \\\\ Second goal:~~Describe how one can design a warm liquid calorimeter integrated into a LHC detector and to list the advantages of the PPC: low price, minimum of mechanical structures, minimum of dead space, easiness of mechanical assembly, accessibility to the electronics, possibility to recirculate the liquid. The absorber and the electronic being outside of the liquid and easily accessible, one has maximum flexibility to define them. \\\\ \\\\ The R&D program, we define here aims at showing the feasibility of these new ideas by building nine towers of twenty gaps and exposing them to electron and hadron beams.

  15. Wood-plastic combination

    International Nuclear Information System (INIS)

    Schaudy, R.

    1978-02-01

    A review on wood-plastic combinations is given including the production (wood and plastic component, radiation hardening, curing), the obtained properties, present applications and prospects for the future of these materials. (author)

  16. DESIGNERS’ KNOWLEDGE IN PLASTICS

    DEFF Research Database (Denmark)

    Eriksen, Kaare

    2013-01-01

    The Industrial designers’ knowledge in plastics materials and manufacturing principles of polymer products is very important for the innovative strength of the industry, according to a group of Danish plastics manufacturers, design students and practicing industrial designers. These three groups ...

  17. Design for Play

    DEFF Research Database (Denmark)

    Feder, Karen

    2017-01-01

    Abstract The purpose of the new Design for Play initiative is to inspire and educate designers to design for the future of play. To create “play ambassadors” equipped with excellent tools, methods, approaches and mind-sets to design for the playful human being in an ever-changing world. To teach...... and inspire children to grow up to be creative designers of their own life and the world around them. The Design for Play research team will study the interplay between people, processes and products in design for play and support the development of playful designers, playful solutions and playful experiences...

  18. Plasticity characteristic obtained by indentation

    International Nuclear Information System (INIS)

    Milman, Yu V

    2008-01-01

    A dimensionless parameter δ H = ε p /ε t (where ε p and ε t are the average values of plastic and total deformation of material on the contact area indenter-specimen) may be used as the plasticity characteristic of materials, which made it possible to characterize the plasticity of materials that are brittle in standard mechanical tests. δ H may be calculated from the values of microhardness HM, Young's modulus E and Poisson's ratio ν. In instrumented indentation the plasticity characteristic δ A = A p /A t (A p and A t are the work of plastic and total deformation during indentation) may be calculated. δ A ∼ δ H for materials with δ H > 0.5, i.e. for all metals and the majority of ceramic materials. In this case, the theoretical equation δ A ∼ δ H = 1-10.2 · (1 - ν - 2ν 2 )(HM/E) is satisfied in experiments with the Berkovich indenter. The influence of the temperature and structural parameters (dislocation density and grain size including nanostructured materials) on δ H is discussed

  19. Why do adult dogs 'play'?

    Science.gov (United States)

    Bradshaw, John W S; Pullen, Anne J; Rooney, Nicola J

    2015-01-01

    Among the Carnivora, play behaviour is usually made up of motor patterns characteristic of predatory, agonistic and courtship behaviour. Domestic dogs are unusual in that play is routinely performed by adults, both socially, with conspecifics and with humans, and also asocially, with objects. This enhanced playfulness is commonly thought to be a side effect of paedomorphosis, the perpetuation of juvenile traits into adulthood, but here we suggest that the functions of the different types of play are sufficiently distinct that they are unlikely to have arisen through a single evolutionary mechanism. Solitary play with objects appears to be derived from predatory behaviour: preferred toys are those that can be dismembered, and a complex habituation-like feedback system inhibits play with objects that are resistant to alteration. Intraspecific social play is structurally different from interspecific play and may therefore be motivationally distinct and serve different goals; for example, dogs often compete over objects when playing with other dogs, but are usually more cooperative when the play partner is human. The majority of dogs do not seem to regard competitive games played with a human partner as "dominance" contests: rather, winning possession of objects during games appears to be simply rewarding. Play may be an important factor in sociality, since dogs are capable of extracting social information not only from games in which they participate, but also from games that they observe between third parties. We suggest that the domestic dog's characteristic playfulness in social contexts is an adaptive trait, selected during domestication to facilitate both training for specific purposes, and the formation of emotionally-based bonds between dog and owner. Play frequency and form may therefore be an indicator of the quality of dog-owner relationships. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Fundamentals of the theory of plasticity

    CERN Document Server

    Kachanov, L M

    2004-01-01

    Intended for use by advanced engineering students and professionals, this volume focuses on plastic deformation of metals at normal temperatures, as applied to strength of machines and structures. 1971 edition.

  1. Play at Work

    DEFF Research Database (Denmark)

    Meier Sørensen, Bent; Spoelstra, Sverre

    2012-01-01

    The interest in organizational play is growing, both in popular business discourse and organization studies. As the presumption that play is dysfunctional for organizations is increasingly discarded, the existing positions may be divided into two camps; one proposes ‘serious play’ as an engine fo...... workplaces engage in play: play as a (serious) continuation of work, play as a (critical) intervention into work and play as an (uninvited) usurpation of work....

  2. Plastic crystal phases of simple water models

    International Nuclear Information System (INIS)

    Aragones, J. L.; Vega, C.

    2009-01-01

    We report the appearance of two plastic crystal phases of water at high pressure and temperature using computer simulations. In one of them the oxygen atoms form a body centered cubic structure (bcc) and in the other they form a face centered cubic structure (fcc). In both cases the water molecules were able to rotate almost freely. We have found that the bcc plastic crystal transformed into a fcc plastic crystal via a Martensitic phase transition when heated at constant pressure. We have performed the characterization and localization in the phase diagram of these plastic crystal phases for the SPC/E, TIP4P, and TIP4P/2005 water potential models. For TIP4P/2005 model free energy calculations were carried out for the bcc plastic crystal and fcc plastic crystal using a new method (which is a slight variation of the Einstein crystal method) proposed for these types of solid. The initial coexistence points for the SPC/E and TIP4P models were obtained using Hamiltonian Gibbs–Duhem integration. For all of these models these two plastic crystal phases appear in the high pressure and temperature region of the phase diagram. It would be of interest to study if such plastic crystal phases do indeed exist for real water. This would shed some light on the question of whether these models can describe satisfactorily the high pressure part of the phase diagram of water, and if not, where and why they fail.

  3. Plastic value chains

    DEFF Research Database (Denmark)

    Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

    2014-01-01

    Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example......, plastics from WEEE is chosen as a Nordic case study. The project aims to propose a number of improvements for this value chain together with representatives from Nordic stakeholders. Based on the experiences made, a guide for other plastic value chains shall be developed....

  4. Playing on the edge

    DEFF Research Database (Denmark)

    Cermak-Sassenrath, Daniel

    2018-01-01

    and specific ways. For instance, gambling for money, party and drinking games, professional play and show sports, art installations, violent and military propaganda computer games, pervasive/mobile gaming, live-action role playing, festivals, performances, and games such as Ghosting and Planking. It is argued......Everything gets more interesting, challenging, or intense the closer it gets to the edge, and so does play. How edgy can play become and still be play? Based on Huizinga’s notion of play, this chapter discusses how a wide range of playful activities pushes the boundaries of play in different...... that in concert with a number of characteristics that mark an activity as play, play is essentially a subjective perspective and individual decision of the player. Huizinga calls this attitude the play spirit, which informs a player’s actions and is in turn sustained by them. Edgy digital or mobile games do...

  5. Challenges in plastics recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann

    2015-01-01

    Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study...... was undertaken to investigate the factors affecting quality in plastics recycling. The preliminary results showed factors primarily influencing quality of plastics recycling to be polymer cross contamination, presence of additives, non-polymer impurities, and polymer degradation. Deprivation of plastics quality......, with respect to recycling, has been shown to happen throughout the plastics value chain, but steps where improvements may happen have been preliminary identified. Example of Cr in plastic samples analysed showed potential spreading and accumulation of chemicals ending up in the waste plastics. In order...

  6. Algorithm for the treatment of the material plastic anisotropy and its introduction into a non-linear structural analysis code (NOSA)

    Energy Technology Data Exchange (ETDEWEB)

    Toselli, G. [ENEA, Centro Ricerche Ezio Clementel, Bologna, (Italy). Dipt. Innovazione; Mirco, A. M. [Bologna Univ., Bologna (Italy). Dipt. di Matematica

    1999-07-01

    In this technical report the thesis of doctor's degree in Mathematics of A.M. Mirco is reported; it has been developed at ENEA research centre 'E. Clementel' in Bologna (Italy) in the frame of a collaboration between the section MACO (Applied Physics Division - Innovation Department) of ENEA at Bologna and the Department of Mathematics of the mathematical, physical and natural sciences faculty of Bologna University. Substantially, studies and research work, developed in these last years at MACO section, are here presented; they have led to the development of a constitutive model, based on Hill potential theory, for the treatment, in plastic field, of metal material anisotropy induced by previous workings and to the construction of the corresponding FEM algorithm for the non-linear structural analysis NOSA, oriented in particular to the numerical simulation of metal forming. Subsequently, an algorithm extension (proper object of the thesis), which has given, beyond a more rigorous formalization, also significant improvements. [Italian] In questo rapporto tecnico viene riportata la tesi di laurea in matematica di A. M. Mirco, tesi svolta presso il centro ricerche E. Clementel dell'ENEA di Bologna nell'ambito di un accordo di collaborazione fra la sezione MACO (Divisione Fisica Applicata - Dipartimento di Innovazione) dell'ENEA di Bologna ed il Dipartimento di matematica della facolta' di scienze matematiche, fisiche e naturali dell'universita' degli studi di Bologna. Sostanzialmente, vengono presentati gli studi ed il lavoro di ricerca, svolti in questi ultimi anni presso la sezione MACO, che hanno portato allo sviluppo di un modello costitutivo, basato sulla teoria del potenziale di Hill, per il trattamento in campo plastico, dell'anisotropia indotta da lavorazioni precedenti per un materiale metallico ed alla costruzione del corrispondente algoritmo basato sul metodo degli elementi finiti per il codice di analisi

  7. The Play of Psychotherapy

    Science.gov (United States)

    Marks-Tarlow, Terry

    2012-01-01

    The author reviews the role of play within psychotherapy. She does not discuss the formal play therapy especially popular for young children, nor play from the Jungian perspective that encourages the use of the sand tray with adults. Instead, she focuses on the informal use of play during psychotherapy as it is orchestrated intuitively. Because…

  8. Play Therapy. ERIC Digest.

    Science.gov (United States)

    Landreth, Garry; Bratton, Sue

    Play therapy is based on developmental principles and, thus, provides, through play, developmentally appropriate means of expression and communication for children. Therefore, skill in using play therapy is an essential tool for mental health professionals who work with children. Therapeutic play allows children the opportunity to express…

  9. The role of play

    NARCIS (Netherlands)

    Schouten, B.A.M.

    2011-01-01

    Play is seen as an activity that is fun, voluntary, offers escape, and is fundamentally exciting. Play is however, more than that; it is a working model of flexibility! There is a vital link between play, psychological development and learning. Moreover, the importance of play has gained importance

  10. [Survey of plasticizers in polyvinyl chloride toys].

    Science.gov (United States)

    Abe, Yutaka; Yamaguchi, Miku; Mutsuga, Motoh; Hirahara, Yoshichika; Kawamura, Yoko

    2012-01-01

    Plasticizers in 101 samples of polyvinyl chloride (PVC) toys on the Japanese market were surveyed. No phthalates were detected in designated toys, though bis(2-ethylhexyl)phthalate, diisononyl phthalate, diisobutyl phthalate, dibutyl phthalate, diisodecyl phthalate and benzyl butyl phthalate were detected in more than half of other toys. 2,2,4-Tributyl-1,3-pentanediol diisobutylate, o-acetyl tributyl citrate, adipates and diacetyl lauroyl glycerol, which are alternative plasticizers to phthalates, were detected. The results of structural analysis confirmed the presence of di(2-ethylhexyl)terephthalate, tributyl citrate, diisononyl 1,2-cyclohexanedicarboxylate and neopentyl glycol esters; these have not previonsly been reported in Japan. There appears to be a shift in plasticizers used for designated toys from phthalates to new plasticizers, and the number of different plasticizers is increasing.

  11. Plasticity of pressure-sensitive materials

    CERN Document Server

    Ochsner, Andreas

    2014-01-01

    Classical plasticity theory of metals is independent of the hydrostatic pressure. However, if the metal contains voids or pores or if the structure is composed of cells, this classical assumption is no more valid and the influence of the hydrostatic pressure must be incorporated in the constitutive description. Looking at the microlevel, metal plasticity is connected with the uniform planes of atoms organized with long-range order. Planes may slip past each other along their close-packed directions. The result is a permanent change of shape within the crystal and plastic deformation. The presence of dislocations increases the likelihood of planes slipping. Nowadays, the theory of pressure sensitive plasticity is successfully applied to many other important classes of materials (polymers, concrete, bones etc.) even if the phenomena on the micro-level are different to classical plasticity of metals. The theoretical background of this phenomenological approach based on observations on the macro-level is describe...

  12. Child's Play: Therapist's Narrative

    Science.gov (United States)

    Reddy, Rajakumari P.; Hirisave, Uma

    2014-01-01

    Play has been recognized as an essential component to children's healthy development. Schools of play therapy differ philosophically and technically, but they all embrace the therapeutic and developmental properties of play. This case report is an illustration of how a 6-year-old child with emotional disorder was facilitated to express concerns in child-centered play therapy. The paper discusses the therapist's narration of the child's play. PMID:24860228

  13. Pathological Plasticity in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Brandon S. Martin

    2012-01-01

    Full Text Available Deficits in neuronal plasticity are common hallmarks of many neurodevelopmental disorders. In the case of fragile-X syndrome (FXS, disruption in the function of a single gene, FMR1, results in a variety of neurological consequences directly related to problems with the development, maintenance, and capacity of plastic neuronal networks. In this paper, we discuss current research illustrating the mechanisms underlying plasticity deficits in FXS. These processes include synaptic, cell intrinsic, and homeostatic mechanisms both dependent on and independent of abnormal metabotropic glutamate receptor transmission. We place particular emphasis on how identified deficits may play a role in developmental critical periods to produce neuronal networks with permanently decreased capacity to dynamically respond to changes in activity central to learning, memory, and cognition in patients with FXS. Characterizing early developmental deficits in plasticity is fundamental to develop therapies that not only treat symptoms but also minimize the developmental pathology of the disease.

  14. The neural cell adhesion molecule-derived peptide FGL facilitates long-term plasticity in the dentate gyrus in vivo

    DEFF Research Database (Denmark)

    Dallérac, Glenn; Zerwas, Meike; Novikova, Tatiana

    2011-01-01

    The neural cell adhesion molecule (NCAM) is known to play a role in developmental and structural processes but also in synaptic plasticity and memory of the adult animal. Recently, FGL, a NCAM mimetic peptide that binds to the Fibroblast Growth Factor Receptor 1 (FGFR-1), has been shown to have...... a beneficial impact on normal memory functioning, as well as to rescue some pathological cognitive impairments. Whether its facilitating impact may be mediated through promoting neuronal plasticity is not known. The present study was therefore designed to test whether FGL modulates the induction...

  15. Alibis for Adult Play

    Science.gov (United States)

    2017-01-01

    The social meanings of play sit at odds with norms of responsible and productive adult conduct. To be “caught” playing as an adult therefore risks embarrassment. Still, many designers want to create enjoyable, nonembarrassing play experiences for adults. To address this need, this article reads instances of spontaneous adult play through the lens of Erving Goffman’s theory of the interaction order to unpack conditions and strategies for nonembarrassing adult play. It identifies established frames, segregated audiences, scripts supporting smooth performance, managing audience awareness, role distancing, and, particularly, alibis for play: Adults routinely provide alternative, adult-appropriate motives to account for their play, such as child care, professional duties, creative expression, or health. Once legitimized, the norms and rules of play themselves then provide an alibi for behavior that would risk being embarrassing outside play.

  16. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

  17. Our plastic age.

    Science.gov (United States)

    Thompson, Richard C; Swan, Shanna H; Moore, Charles J; vom Saal, Frederick S

    2009-07-27

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation.

  18. Our plastic age

    Science.gov (United States)

    Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation. PMID:19528049

  19. Endocannabinoid System and Synaptic Plasticity: Implications for Emotional Responses

    Directory of Open Access Journals (Sweden)

    María-Paz Viveros

    2007-01-01

    Full Text Available The endocannabinoid system has been involved in the regulation of anxiety, and proposed as an inhibitory modulator of neuronal, behavioral and adrenocortical responses to stressful stimuli. Brain regions such as the amygdala, hippocampus and cortex, which are directly involved in the regulation of emotional behavior, contain high densities of cannabinoid CB1 receptors. Mutant mice lacking CB1 receptors show anxiogenic and depressive-like behaviors as well as an altered hypothalamus pituitary adrenal axis activity, whereas enhancement of endocannabinoid signaling produces anxiolytic and antidepressant-like effects. Genetic and pharmacological approaches also support an involvement of endocannabinoids in extinction of aversive memories. Thus, the endocannabinoid system appears to play a pivotal role in the regulation of emotional states. Endocannabinoids have emerged as mediators of short- and long- term synaptic plasticity in diverse brain structures. Despite the fact that most of the studies on this field have been performed using in vitro models, endocannabinoid-mediated plasticity might be considered as a plausible candidate underlying some of the diverse physiological functions of the endogenous cannabinoid system, including developmental, affective and cognitive processes. In this paper, we will focus on the functional relevance of endocannabinoid-mediated plasticity within the framework of emotional responses. Alterations of the endocannabinoid system may constitute an important factor in the aetiology of certain neuropsychiatric disorders, and, in turn, enhancers of endocannabinoid signaling could represent a potential therapeutical tool in the treatment of both anxiety and depressive symptoms.

  20. On lower order strain gradient plasticity theories

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Hutchinson, J. W.

    2002-01-01

    By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter...

  1. Plasticity of the Axon Initial Segment

    DEFF Research Database (Denmark)

    Petersen, Anders Victor; Cotel, Florence; Perrier, Jean François

    2017-01-01

    of metabotropic receptors modulates the properties of ion channels expressed at the AIS within seconds and consequently produces fast adjustments of neuronal excitability. Recent results suggest that this plasticity plays important roles in physiological functions as diverse as memory formation, hearing...

  2. Plastic Pollution from Ships

    OpenAIRE

    Čulin, Jelena; Bielić, Toni

    2016-01-01

    The environmental impact of shipping on marine environment includes discharge of garbage. Plastic litter is of particular concern due to abundance, resistance to degradation and detrimental effect on marine biota. According to recently published studies, a further research is required to assess human health risk. Monitoring data indicate that despite banning plastic disposal at sea, shipping is still a source of plastic pollution. Some of the measures to combat the problem are discussed.

  3. ENVIRONMENTAL ISSUE-PLASTIC

    OpenAIRE

    Sunita Shakle

    2017-01-01

    Polythene is the most common plastic, the annual global production is approximately 60 million tones, and its primary use is in packing. Plastic bags pollute soil and waters and kill thousands of marine generalize plastic bags are not biodegradable they clog water ways, spoil the land scape and end up in landfills. Where they may take 1000 year or more to break down into ever smaller particals that continue to pollution the soil and water.

  4. Our plastic age

    OpenAIRE

    Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste pl...

  5. Methodology for plastic fracture - a progress report

    International Nuclear Information System (INIS)

    Wilkinson, J.P.D.; Smith, R.E.E.

    1977-01-01

    This paper describes the progress of a study to develop a methodology for plastic fracture. Such a fracture mechanics methodology, having application in the plastic region, is required to assess the margin of safety inherent in nuclear reactor pressure vessels. The initiation and growth of flaws in pressure vessels under overload conditions is distinguished by a number of unique features, such as large scale yielding, three-dimensional structural and flaw configurations, and failure instabilities that may be controlled by either toughness or plastic flow. In order to develop a broadly applicable methodology of plastic fracture, these features require the following analytical and experimental studies: development of criteria for crack initiation and growth under large scale yielding; the use of the finite element method to describe elastic-plastic behaviour of both the structure and the crack tip region; and extensive experimental studies on laboratory scale and large scale specimens, which attempt to reproduce the pertinent plastic flow and crack growth phenomena. This discussion centers on progress to date on the selection, through analysis and laboratory experiments, of viable criteria for crack initiation and growth during plastic fracture. (Auth.)

  6. Plasticity: modeling & computation

    National Research Council Canada - National Science Library

    Borja, Ronaldo Israel

    2013-01-01

    .... "Plasticity Modeling & Computation" is a textbook written specifically for students who want to learn the theoretical, mathematical, and computational aspects of inelastic deformation in solids...

  7. Synaptic Plasticity and Nociception

    Institute of Scientific and Technical Information of China (English)

    ChenJianguo

    2004-01-01

    Synaptic plasticity is one of the fields that progresses rapidly and has a lot of success in neuroscience. The two major types of synaptie plasticity: long-term potentiation ( LTP and long-term depression (LTD are thought to be the cellular mochanisms of learning and memory. Recently, accumulating evidence suggests that, besides serving as a cellular model for learning and memory, the synaptic plasticity involves in other physiological or pathophysiological processes, such as the perception of pain and the regulation of cardiovascular system. This minireview will focus on the relationship between synaptic plasticity and nociception.

  8. Plastics and health risks.

    Science.gov (United States)

    Halden, Rolf U

    2010-01-01

    By 2010, the worldwide annual production of plastics will surpass 300 million tons. Plastics are indispensable materials in modern society, and many products manufactured from plastics are a boon to public health (e.g., disposable syringes, intravenous bags). However, plastics also pose health risks. Of principal concern are endocrine-disrupting properties, as triggered for example by bisphenol A and di-(2-ethylhexyl) phthalate (DEHP). Opinions on the safety of plastics vary widely, and despite more than five decades of research, scientific consensus on product safety is still elusive. This literature review summarizes information from more than 120 peer-reviewed publications on health effects of plastics and plasticizers in lab animals and humans. It examines problematic exposures of susceptible populations and also briefly summarizes adverse environmental impacts from plastic pollution. Ongoing efforts to steer human society toward resource conservation and sustainable consumption are discussed, including the concept of the 5 Rs--i.e., reduce, reuse, recycle, rethink, restrain--for minimizing pre- and postnatal exposures to potentially harmful components of plastics.

  9. Children, Time, and Play

    DEFF Research Database (Denmark)

    Elkind, David; Rinaldi, Carla; Flemmert Jensen, Anne

    Proceedings from the conference "Children, Time, and Play". Danish University of Education, January 30th 2003.......Proceedings from the conference "Children, Time, and Play". Danish University of Education, January 30th 2003....

  10. Role-Playing Mitosis.

    Science.gov (United States)

    Wyn, Mark A.; Stegink, Steven J.

    2000-01-01

    Introduces a role playing activity that actively engages students in the learning process of mitosis. Students play either chromosomes carrying information, or cells in the cell membrane. (Contains 11 references.) (Author/YDS)

  11. Play the MRI Game

    Science.gov (United States)

    ... Teachers' Questionnaire MRI Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  12. Play the Tuberculosis Game

    Science.gov (United States)

    ... Questionnaire Tuberculosis Play Tuberculosis Experiments & Discoveries About the game Discover and experience some of the classic methods ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  13. Play the Electrocardiogram Game

    Science.gov (United States)

    ... and Work Teachers' Questionnaire Electrocardiogram Play the ECG Game About the game ECG is used for diagnosing heart conditions by ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  14. [Play therapy in hospital].

    Science.gov (United States)

    Gold, Katharina; Grothues, Dirk; Leitzmann, Michael; Gruber, Hans; Melter, Michael

    2012-01-01

    The following article presents an overview of current research studies on play therapy in the hospital. It highlights individual diagnoses for which play therapy has shown reasonable success. The aim of this review is to describe the current status of the scientific debate on play therapy for sick children in order to allow conclusions regarding the indications for which play therapy is or might be useful.

  15. The Pedagogy of Play

    Science.gov (United States)

    Giesbrecht, Sheila

    2012-01-01

    Play is important. Environmental educators Sobel and Louv write about the relationship between children and outside play and suggest that early transcendental experiences within nature allow children to develop empathetic orientations towards the natural world. Children who play out-of-doors develop an appreciation for the environment and…

  16. The play grid

    DEFF Research Database (Denmark)

    Fogh, Rune; Johansen, Asger

    2013-01-01

    In this paper we propose The Play Grid, a model for systemizing different play types. The approach is psychological by nature and the actual Play Grid is based, therefore, on two pairs of fundamental and widely acknowledged distinguishing characteristics of the ego, namely: extraversion vs. intro...

  17. Play the Mosquito Game

    Science.gov (United States)

    ... and Work Teachers' Questionnaire Malaria Play the Mosquito Game Play the Parasite Game About the games Malaria is one of the world's most common ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  18. Playing with the city

    DEFF Research Database (Denmark)

    Tosca, Susana; Marquez, Israel

    2017-01-01

    In this paper we introduce and describe the phenomenon of videogame street art as a specific kind of street art. We consider its materiality and significance, and conceptualize it in the light of a double manifestation of play: the playful appropriation of the city by the artist and the fact...... that street art encapsulates the act of playing videogames in a visual form. Digital play spills out of our computer screens and occupies the urban space with the explicit intention of involving spectators, who are invited to play in symbolic ways that actualize nostalgic memories of gaming and can be related...

  19. Affect and the computer game player: the effect of gender, personality, and game reinforcement structure on affective responses to computer game-play.

    Science.gov (United States)

    Chumbley, Justin; Griffiths, Mark

    2006-06-01

    Previous research on computer games has tended to concentrate on their more negative effects (e.g., addiction, increased aggression). This study departs from the traditional clinical and social learning explanations for these behavioral phenomena and examines the effect of personality, in-game reinforcement characteristics, gender, and skill on the emotional state of the game-player. Results demonstrated that in-game reinforcement characteristics and skill significantly effect a number of affective measures (most notably excitement and frustration). The implications of the impact of game-play on affect are discussed with reference to the concepts of "addiction" and "aggression."

  20. Playing with social identities

    DEFF Research Database (Denmark)

    Winther-Lindqvist, Ditte Alexandra

    2013-01-01

    as pretence, children’s play is understood as an activity involving rules of the social order (roles and positions) as well as identification processes (imagined situations). The theoretical argumentation builds on empirical examples obtained in two different Danish day-care centres. The chapter is informed...... by ethnographic observations and draws on illustrative examples with symbolic group play as well as game-play with rules (soccer) among 5 year old boys. Findings suggest that day-care children’s play, involves negotiation of roles, positioning and identification, and rules – and that these negotiations......This chapter offers support for Vygotsky’s claim that all play involves both an imagined situation as well as rules. Synthesising Schousboe’s comprehensive model of spheres of realities in playing (see Chapter 1, this volume) with Lev Vygotskys insight that all playing involve rules as well...

  1. Network evolution induced by asynchronous stimuli through spike-timing-dependent plasticity.

    Directory of Open Access Journals (Sweden)

    Wu-Jie Yuan

    Full Text Available In sensory neural system, external asynchronous stimuli play an important role in perceptual learning, associative memory and map development. However, the organization of structure and dynamics of neural networks induced by external asynchronous stimuli are not well understood. Spike-timing-dependent plasticity (STDP is a typical synaptic plasticity that has been extensively found in the sensory systems and that has received much theoretical attention. This synaptic plasticity is highly sensitive to correlations between pre- and postsynaptic firings. Thus, STDP is expected to play an important role in response to external asynchronous stimuli, which can induce segregative pre- and postsynaptic firings. In this paper, we study the impact of external asynchronous stimuli on the organization of structure and dynamics of neural networks through STDP. We construct a two-dimensional spatial neural network model with local connectivity and sparseness, and use external currents to stimulate alternately on different spatial layers. The adopted external currents imposed alternately on spatial layers can be here regarded as external asynchronous stimuli. Through extensive numerical simulations, we focus on the effects of stimulus number and inter-stimulus timing on synaptic connecting weights and the property of propagation dynamics in the resulting network structure. Interestingly, the resulting feedforward structure induced by stimulus-dependent asynchronous firings and its propagation dynamics reflect both the underlying property of STDP. The results imply a possible important role of STDP in generating feedforward structure and collective propagation activity required for experience-dependent map plasticity in developing in vivo sensory pathways and cortices. The relevance of the results to cue-triggered recall of learned temporal sequences, an important cognitive function, is briefly discussed as well. Furthermore, this finding suggests a potential

  2. Smart film actuators using biomass plastic

    International Nuclear Information System (INIS)

    Yoneyama, Satoshi; Tanaka, Nobuo

    2011-01-01

    This paper presents a novel smart film actuator based on the use of a biomass plastic as a piezoelectric film. Conventional polymeric smart sensors and actuators have been based upon synthetic piezoelectric polymer films such as PVDF. Almost all synthetic polymers are made from nearly depleted oil resources. In addition combustion of their materials releases carbon dioxide, thereby contributing to global warming. Thus at least two important sustainability principles are violated when employing synthetic polymers: avoiding depletable resources and avoiding ecosystem destruction. To overcome such problems, industrial plastic products made from synthetic polymers were developed to replace oil-based plastics with biomass plastics. This paper applies a biomass plastic with piezoelectricity such as poly-L-lactic acid (PLLA). As a result, PLLA film becomes a distributed parameter actuator per se, hence an environmentally conscious smart film actuator is developed. Firstly, this paper overviews the fundamental properties of piezoelectric synthetic polymers and biopolymers. The concept of carbon neutrality using biopolymers is mentioned. Then a two-dimensional modal actuator for exciting a specific structural mode is proposed. Furthermore, a biomass plastic-based cantilever beam with the capability of modal actuation is developed, the validity of the proposed smart film actuator based upon a biomass plastic being analytically as well as experimentally verified

  3. FairyPlay

    DEFF Research Database (Denmark)

    Toft, Herdis

    2018-01-01

    in a play culture where children recycle them in transmitted, transformed and transgressive modes. His fairy tales function as raw materials – trash – for play-production, and these contemporary children muddle, mingle, remix their formulas and elements with other materials and adjust them to a play context......Hans Christian Andersen is a cultural icon in the Danish community, and his fairy tales are canonized as treasured Danish cultural heritage. However, situated as they are today in a crosscultural mix between folklore, booklore and medialore, they also may be analysed as useful, treasured trash...... through improvisations. So they perform what we shall name FairyPlay - just like Hans Christian Andersen himself did. We show Hans Christian Andersen as an intimate connoisseur of play culture, a homo ludens, a trash-sculptor and a thing-finder, like Pippi Longstocking and like children in play. Examples...

  4. Insights into the structure-activity relationship of the anticancer compound ZJ-101, a derivative of marine natural product superstolide A: A role played by the lactone moiety.

    Science.gov (United States)

    Qiu, Haibo; Qian, Shan; Head, Sarah A; Liu, Jun O; Jin, Zhendong

    2016-10-01

    Compound ZJ-101, a structurally simplified analog of the marine natural product superstolide A, was previously developed in our laboratory. In the subsequent structure-activity relationship study, a new analog ZJ-109 was designed and synthesized to probe the importance of the lactone moiety of the molecule by replacing the lactone in ZJ-101 with a lactam. The biological evaluation showed that ZJ-109 is about 8-12 times less active against cancer cells in vitro than ZJ-101, suggesting that the lactone moiety of the molecule is important for its anticancer activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Thermal degradation and plasticizing mechanism of poly(vinyl chloride) plasticized with a novel cardanol derived plasticizer

    Science.gov (United States)

    Chen, J.; Nie, X. A.; Jiang, J. C.; Zhou, Y. H.

    2018-01-01

    A natural plasticizer cardanol derivatives glycidyl ether (CGE) was synthesized and employed as a plasticizer for the poly(vinyl chloride). The effect of CGE on thermal degradation of PVC films and its plasticizing mechanism were firstly reported. The molecular structure of CGE was characterized with Fourier transform infrared spectroscopy (FTIR). Thermal properties, degradation properties and compatibility of the PVC films were investigated by Differential scanning calorimeter analysis (DSC), Thermogravimetric analysis (TGA) and FTIR, respectively. Compared with the commercial plasticizers dioctylphthalate (DOP), CGE can endow PVC film with a decrease of 4.31 °C in glass transition temperature (Tg), an increase of 24.01 °C and 25.53 °C in 10% weight loss (T 10) and 50% weight loss (T 50) respectively, and a higher activetion energy of thermal degradation (Ea ).

  6. Why do Dolphins Play?

    Directory of Open Access Journals (Sweden)

    Stan A. Kuczaj

    2014-05-01

    Full Text Available Play is an important aspect of dolphin life, perhaps even an essential one. Play provides opportunities for dolphin calves to practice and perfect locomotor skills, including those involved in foraging and mating strategies and behaviors. Play also allows dolphin calves to learn important social skills and acquire information about the characteristics and predispositions of members of their social group, particularly their peers. In addition to helping dolphin calves learn how to behave, play also provides valuable opportunities for them to learn how to think. The ability to create and control play contexts enables dolphins to create novel experiences for themselves and their playmates under relatively safe conditions. The behavioral variability and individual creativity that characterize dolphin play yield ample opportunities for individual cognitive development as well as social learning, and sometimes result in innovations that are reproduced by other members of the group. Although adults sometimes produce innovative play, calves are the primary source of such innovations. Calves are also more likely to imitate novel play behaviors than are adults, and so calves contribute significantly to both the creation and transmission of novel play behaviors within a group. Not unexpectedly, then, the complexity of dolphin play increases with the involvement of peers. As a result, the opportunity to observe and/or interact with other dolphin calves enhances the effects of play on the acquisition and maintenance of flexible problem solving skills, the emergence and strengthening of social and communicative competencies, and the establishment of social relationships. It seems that play may have evolved to help young dolphins learn to adapt to novel situations in both their physical and social worlds, the beneficial result being a set of abilities that increases the likelihood that an individual survives and reproduces.

  7. Work Hard / Play Hard

    OpenAIRE

    Burrows, J.; Johnson, V.; Henckel, D.

    2016-01-01

    Work Hard / Play Hard was a participatory performance/workshop or CPD experience hosted by interdisciplinary arts atelier WeAreCodeX, in association with AntiUniversity.org. As a socially/economically engaged arts practice, Work Hard / Play Hard challenged employees/players to get playful, or go to work. 'The game changes you, you never change the game'. Employee PLAYER A 'The faster the better.' Employer PLAYER B

  8. The extrinsic influence of carbon fibre reinforced plastic laminates to ...

    Indian Academy of Sciences (India)

    The extrinsic influence of carbon fibre reinforced plastic laminates to strengthen steel structures ... The intrinsic advantages of strengthening the steel-based structures by the use of fibre reinforced plastic (FRP) material have ... Sadhana | News.

  9. Free riders play fair

    OpenAIRE

    Takikawa, Hirohide

    2012-01-01

    After the demise of the social contract theory, the argument from fair play, which employs the principle of fair play, has been widely acknowledged as one of the most promising ways of justifying political obligation. First, I articulate the most promising version of the principle of fair play. Then, I show that free riders play fair, that is, that their moral fault lies not in unfairness but in the violation of a rule by appealing to the example of three-in-a-boat. Finally, I conclude that e...

  10. Designing for Immediate Play

    DEFF Research Database (Denmark)

    Pichlmair, Martin; Mech, Lena; Sicart, Miguel Angel

    2017-01-01

    This paper is concerned with designing for immediate play, the experience that a player has when joining a game designed for being played without particular preparation. Museum games, urban games, casual sports, and ad-hoc multiplayer video games are kinds of games that facilitate immediate play...... offer using examples and expert opinions. While most practices and game examples mentioned in this paper are from non-digital games, a special focus is put on the role of technology in immediately playable experiences. Still, the examined design dimensions are independent of the technological foundation...... of the game. This paper provides a starting point for designing better immediate play situations....

  11. Late Modern Play Culture

    DEFF Research Database (Denmark)

    Karoff, Helle Skovbjerg

    2008-01-01

    and the Danish University of Education (among others) have been working with different kind of products, all referred to as PlAYWARE. Playware combines modern technology and knowledge about play culture in order to produce playful experiences for its players. This paper will exemplify how the concept of play can...... from one generation to the next. Because older children are no longer present as younger children grow up, the traditional "cultural leaders" are gone. They have taken with them much of the inspiration for play as well as important knowledge about how to organise a game. In that sense we can say...

  12. Global change and the evolution of phenotypic plasticity in plants.

    Science.gov (United States)

    Matesanz, Silvia; Gianoli, Ernesto; Valladares, Fernando

    2010-09-01

    Global change drivers create new environmental scenarios and selective pressures, affecting plant species in various interacting ways. Plants respond with changes in phenology, physiology, and reproduction, with consequences for biotic interactions and community composition. We review information on phenotypic plasticity, a primary means by which plants cope with global change scenarios, recommending promising approaches for investigating the evolution of plasticity and describing constraints to its evolution. We discuss the important but largely ignored role of phenotypic plasticity in range shifts and review the extensive literature on invasive species as models of evolutionary change in novel environments. Plasticity can play a role both in the short-term response of plant populations to global change as well as in their long-term fate through the maintenance of genetic variation. In new environmental conditions, plasticity of certain functional traits may be beneficial (i.e., the plastic response is accompanied by a fitness advantage) and thus selected for. Plasticity can also be relevant in the establishment and persistence of plants in novel environments that are crucial for populations at the colonizing edge in range shifts induced by climate change. Experimental studies show taxonomically widespread plastic responses to global change drivers in many functional traits, though there is a lack of empirical support for many theoretical models on the evolution of phenotypic plasticity. Future studies should assess the adaptive value and evolutionary potential of plasticity under complex, realistic global change scenarios. Promising tools include resurrection protocols and artificial selection experiments. © 2010 New York Academy of Sciences.

  13. Playfulness and Openness

    DEFF Research Database (Denmark)

    Marchetti, Emanuela; Petersson, Eva

    2011-01-01

    What does it mean to design a playful learning tool? What is needed for a learning tool to be perceived by potential users as playful? These questions emerged reflecting on a Participatory Design process aimed at enhancing museum-learning practice from the perspective of primary school children...

  14. Play framework cookbook

    CERN Document Server

    Reelsen, Alexander

    2015-01-01

    This book is aimed at advanced developers who are looking to harness the power of Play 2.x. This book will also be useful for professionals looking to dive deeper into web development. Play 2 .x is an excellent framework to accelerate your learning of advanced topics.

  15. Five recent play dates

    DEFF Research Database (Denmark)

    Abildgaard, Mette Simonsen; Birkbak, Andreas; Jensen, Torben Elgaard

    2017-01-01

    An advantage of the playground metaphor is that it comes with the activity of going out on ‘play dates’ and developing friendships. In such playful relationships, there is always something at stake, but the interaction is also fun and inherently exploratory. In the following, we take a tour of five...

  16. Communication in Symbolic Play.

    Science.gov (United States)

    Umek, Ljubica Marjanovic; Musek, Petra Lesnik; Kranjc, Simona

    2001-01-01

    Analyzed records of Slovene children's speech from a linguistic point of view and established differences in communication patterns with regard to the children's ages and the type of symbolic play. Found a shift in play from make-believe with regard to objects to roleplay related to social context. The older the child, the more language functions…

  17. Art of Play

    DEFF Research Database (Denmark)

    Froes, Isabel Cristina G.; Walker, Kevin

    2011-01-01

    Play is a key element in cultural development, according to the Dutch historian Johan Huizinga. Nowadays many of us interact with other people in online games and social networks, through multiple digital devices. But harnessing playful activities for museum learning is mostly undeveloped. In thi...

  18. Play your part

    CERN Document Server

    Ramsey, Gaynor

    1978-01-01

    Play your part is a collection of then situations in which students have to take on the roles of particular people and express their opinions, feelings or arguments about the situation. Play your part is intended for use with advanced students of English.

  19. Return to Play

    Science.gov (United States)

    Mangan, Marianne

    2013-01-01

    Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.

  20. MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY

    International Nuclear Information System (INIS)

    Lander, S. K.

    2016-01-01

    The activity of magnetars is believed to be powered by colossal magnetic energy reservoirs. We sketch an evolutionary picture in which internal field evolution in magnetars generates a twisted corona, from which energy may be released suddenly in a single giant flare, or more gradually through smaller outbursts and persistent emission. Given the ages of magnetars and the energy of their giant flares, we suggest that their evolution is driven by a novel mechanism: magnetic flux transport/decay due to persistent plastic flow in the crust, which would invalidate the common assumption that the crustal lattice is static and evolves only under Hall drift and Ohmic decay. We estimate the field strength required to induce plastic flow as a function of crustal depth, and the viscosity of the plastic phase. The star’s superconducting core may also play a role in magnetar field evolution, depending on the star’s spindown history and how rotational vortices and magnetic fluxtubes interact.

  1. Investigation on neutron/gamma discrimination phenomena in plastic scintillators

    International Nuclear Information System (INIS)

    Blanc, Pauline

    2014-01-01

    This PhD topic was born from misunderstandings and incomplete knowledge of the mechanism and relative effectiveness of neutron and gamma-ray (n/γ) discrimination between plastic scintillators compared to liquid scintillators. The shape of the light pulse these materials generate following interaction with an ionizing particle (predominantly recoil protons in the case of neutrons and electrons in the case of gamma-rays) is different in time in a way that depends on the detected particle (nature and energy). It is this fact that enables separation (PSD). The behavior in liquid scintillators has been extensively studied experimentally for practical applications. Only recently has it been shown that a weak separation can also be achieved using specially prepared plastics. The study of this system presents an open field and the understanding of both liquids and plastics with respect to their PSD properties is far from complete. This work is dedicated to exploring the fundamental photophysical phenomena at play in the generation of luminescence emission, following the interaction of ionizing radiation with organic scintillators. For this purpose, firstly a detailed literature review of the state-of-the-art has been conducted extending from 1960 to the present day. Secondly a complete characterization of the main scintillating materials has been conducted to define their fluorescence properties and the characteristics of their scintillation under irradiation. Thirdly a proton beam has been used to simulate recoil protons to quantify under controlled laboratory conditions their specific energy deposition in a plastic scintillator with PSD properties. The fourth part of this thesis is devoted to the study of PSD efficiency of scintillators as a function of their molecular structure. This investigation has led to a plastic scintillator prepared in our laboratory with good PSD properties and a patent submission. Finally, photophysical experiments were performed using a

  2. Influence of the film thickness on the structure, optical and electrical properties of ITO coatings deposited by sputtering at room temperature on glass and plastic substrates

    International Nuclear Information System (INIS)

    Guillén, C; Herrero, J

    2008-01-01

    Transparent and conductive indium tin oxide (ITO) films with thickness between 0.2 and 0.7 µm were deposited by sputtering at room temperature on glass and polyethylene terephthalate (PET) substrates. All films were polycrystalline, with crystallite size increasing and lattice distortion decreasing when the film thickness was increased. Besides, transmission in the near-infrared region is found to be decreasing and carrier concentration increasing when the film thickness was increased. For the same thickness, the lattice distortion is slightly lower and the carrier concentration higher for the layers grown on PET substrates. A direct relationship between the lattice distortion and the free carrier concentration has been established, applying to the films grown on glass and plastic substrates. By adjusting ITO coating thickness, sheet resistance below 15 Ω sq −1 and average visible transmittance about 90% have been achieved by sputtering at room temperature

  3. Stem cell plasticity.

    Science.gov (United States)

    Lakshmipathy, Uma; Verfaillie, Catherine

    2005-01-01

    The central dogma in stem cell biology has been that cells isolated from a particular tissue can renew and differentiate into lineages of the tissue it resides in. Several studies have challenged this idea by demonstrating that tissue specific cell have considerable plasticity and can cross-lineage restriction boundary and give rise to cell types of other lineages. However, the lack of a clear definition for plasticity has led to confusion with several reports failing to demonstrate that a single cell can indeed differentiate into multiple lineages at significant levels. Further, differences between results obtained in different labs has cast doubt on some results and several studies still await independent confirmation. In this review, we critically evaluate studies that report stem cell plasticity using three rigid criteria to define stem cell plasticity; differentiation of a single cell into multiple cell lineages, functionality of differentiated cells in vitro and in vivo, robust and persistent engraft of transplanted cells.

  4. Plastics and environment

    International Nuclear Information System (INIS)

    Avenas, P.

    1996-01-01

    Synthetic organic polymers, such as plastics, PVC, polyamides etc are considered less ecological than natural materials such as wood. Other artificial materials such as metals, glass or biodegradable plastics have also a better image than petroleum products. This short paper demonstrates that the manufacturing or the transport of every material uses energy and that the complete energy balance sheet of a plastic bottle, for instance, is more favourable than the one of a glass bottle. Plastic materials are also easily valorized and recycled and part of the energy spent during manufacturing can be recovered during incineration for district heating. During the life-cycle of such a synthetic material, the same petroleum quantity can be used twice which leads to less negative effects on the environment. Finally, the paper focusses on the problem of biodegradable materials which are not degradable when buried under several meters of wastes and which are a nuisance to recycling. (J.S.)

  5. Recycling of plastics

    Energy Technology Data Exchange (ETDEWEB)

    Kaminsky, W; Menzel, J; Sinn, H

    1976-01-01

    Considering the shortage of raw materials and environmental pollution, the recycling of plastic waste is a very important topic. Pilot plants for research in Funabashi Japan, Franklin (Ohio) U.S.A., and the R 80-process of Krauss Maffei, W. Germany, have demonstrated the possibility of reclaiming plastics from refuse. Old tires and waste from the plastic producing and manufacturing industries are readily available. The pyrolysis of plastic yields gaseous and liquid products, and the exploitation of this cracking reaction has been demonstrated by pilot plants in Japan and Great Britain. Further laboratory scale experiments are taking place in W. Germany. In continuous fluidized beds and in molten salts, polyethylene, polypropylene, polyvinylchloride, polystyrene and rubber are pyrolysed and better than 98 percent conversion is obtained. Up to 40 percent of the feed can be obtained as aromatic compounds, and a pilot plant is under construction. As a first step PVC-containing material can be almost quantitatively dehydrochlorinated.

  6. A Plastic Menagerie

    Science.gov (United States)

    Hadley, Mary Jane

    2010-01-01

    Bobble heads had become quite popular, depicting all sorts of sports figures, animals, and even presidents. In this article, the author describes how her fourth graders made bobble head sculptures out of empty plastic drink bottles. (Contains 1 online resource.)

  7. Art and Plastic Surgery.

    Science.gov (United States)

    Fernandes, Julio Wilson; Metka, Susanne

    2016-04-01

    The roots of science and art of plastic surgery are very antique. Anatomy, drawing, painting, and sculpting have been very important to the surgery and medicine development over the centuries. Artistic skills besides shape, volume, and lines perception can be a practical aid to the plastic surgeons' daily work. An overview about the interactions between art and plastic surgery is presented, with a few applications to rhinoplasty, cleft lip, and other reconstructive plastic surgeries. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

  8. On the formulation of higher gradient single and polycrystal plasticity

    International Nuclear Information System (INIS)

    Menzel, A.; Steinmann, P.

    1998-01-01

    This contribution aims in a geometrically linear formulation of higher gradient plasticity of single and polycrystalline material based on the continuum theory of dislocations and incompatibilities. Thereby, general continuum dislocation densities and incompatibilities are introduced from the viewpoint of continuum mechanics by considering the spatial closure failure of arbitrary line integrals of the displacement differential. Then these findings are translated to the plastic parts of the displacement gradient, the so called plastic distortion, and the plastic strain, respectively, within an elasto-plastic solid thus defining tensor fields of plastic dislocation densities and plastic incompatibilities. Next, in the case of single crystalline material the plastic dislocation density and in the case of polycrystalline material the plastic incompatibility are considered within the exploitation of the thermodynamical principle of positive dissipation. As a result, a phenomenological but physically motivated description of hardening is obtained, which incorporates for single crystals second spatial derivatives of the plastic deformation gradient and for polycrystals fourth spatial derivatives of the plastic strains into the yield condition. Moreover, these modifications mimic the characteristic structure of kinematic hardening, whereby the backstress obeys a nonlocal evolution law. (orig.)

  9. Playful Collaboration (Or Not)

    DEFF Research Database (Denmark)

    Bogers, Marcel; Sproedt, Henrik

    2012-01-01

    This article explores how playing games can be used to teach intangible social interaction across boundaries, in particular within open collaborative innovation. We present an exploratory case study of how students learned from playing a board game in a graduate course of the international...... and interdisciplinary Innovation and Business master's program in Denmark. We identify several important themes related to the process of learning through playing and the social dynamics of open collaborative innovation, while we also highlight possible caveats of “playing” and practicing open innovation. Our findings...

  10. DEVELOPMENT OF PLASTIC SURGERY.

    Science.gov (United States)

    Pećanac, Marija Đ

    2015-01-01

    Plastic surgery is a medical specialty dealing with corrections of defects, improvements in appearance and restoration of lost function. Ancient times. The first recorded account of reconstructive plastic surgery was found in ancient Indian Sanskrit texts, which described reconstructive surgeries of the nose and ears. In ancient Greece and Rome, many medicine men performed simple plastic cosmetic surgeries to repair damaged parts of the body caused by war mutilation, punishment or humiliation. In the Middle Ages, the development of all medical braches, including plastic surgery was hindered. New age. The interest in surgical reconstruction of mutilated body parts was renewed in the XVIII century by a great number of enthusiastic and charismatic surgeons, who mastered surgical disciplines and became true artists that created new forms. Modern era. In the XX century, plastic surgery developed as a modern branch in medicine including many types of reconstructive surgery, hand, head and neck surgery, microsurgery and replantation, treatment of burns and their sequelae, and esthetic surgery. Contemporary and future plastic surgery will continue to evolve and improve with regenerative medicine and tissue engineering resulting in a lot of benefits to be gained by patients in reconstruction after body trauma, oncology amputation, and for congenital disfigurement and dysfunction.

  11. Recycling of packing plastics

    International Nuclear Information System (INIS)

    Gintenreiter-Koegl, S.

    2001-05-01

    The ordinance on the avoidance of packaging waste was a serious intervention in the public and private waste management in Austria. Above all the high expenses for an overall packaging waste collection and the recycling of packaging plastics were criticized. The landfill ordinance comes into force in 2004 and this means another major change in the Austrian waste management system. In the course of this change the overall collection and the recycling and recovery of waste streams, especially of the high caloric plastics waste, have to be discussed again. The goal of this work was on the one hand to develop and adapt the hydrocracking process for the recovery of mixed plastics waste and to show a possible application in Austria. On the other hand the work shows the technical, ecological and economical conditions for packaging plastics recycling and recovery in order to find optimum applications for the processes and to examine their contribution to a sustainable development. A hydrocracking test plant for the processing of mixed plastic wastes was built and had been running for about three years. The tests were carried out successfully and the suitability of the technology for the recovery of packaging plastics could be shown. Results show at least a 35 % yield of fuel. The hydrocracking technology is quite common in the oil industries and therefore an integration on a refinery site is suggested. (author)

  12. Play vs. Procedures

    DEFF Research Database (Denmark)

    Hammar, Emil

    Through the theories of play by Gadamer (2004) and Henricks (2006), I will show how the relationship between play and game can be understood as dialectic and disruptive, thus challenging understandings of how the procedures of games determine player activity and vice versa. As such, I posit some...... analytical consequences for understandings of digital games as procedurally fixed (Boghost, 2006; Flannagan, 2009; Bathwaite & Sharp, 2010). That is, if digital games are argued to be procedurally fixed and if play is an appropriative and dialectic activity, then it could be argued that the latter affects...... and alters the former, and vice versa. Consequently, if the appointed procedures of a game are no longer fixed and rigid in their conveyance of meaning, qua the appropriative and dissolving nature of play, then understandings of games as conveying a fixed meaning through their procedures are inadequate...

  13. Social Media and the Plastic Surgery Patient.

    Science.gov (United States)

    Sorice, Sarah C; Li, Alexander Y; Gilstrap, Jarom; Canales, Francisco L; Furnas, Heather J

    2017-11-01

    Many plastic surgeons use social media as a marketing tool to attract and retain patients, but information about how patients use social media and their preferred types of plastic surgery posts have been lacking. To investigate patients' preferred social media networks and the type of posts they wished to see, a cross-sectional study was conducted in a single aesthetic practice of two plastic surgeons by surveying 100 consecutive patients. The age of the patients averaged 44.4 years (range, 17 to 78 years). Facebook had the greatest patient use and engagement, with YouTube second in use, and Instagram second in number of engaged users. Over half used Pinterest, but with little daily engagement. Only one-fourth used Snapchat, but the percentage of users who were highly engaged was second only to Facebook. The least popular network was Twitter, with the fewest patient users and least engagement. Social media played a minor role compared with the practice's Web site in both influencing patients to choose the practice and providing information on the day of the appointment. Patients most wanted to see posts on a plastic surgeon's social media platform related to practice information, before-and-after photographs, and contests. Articles about plastic surgery held the least interest. Among five types of Web site content, patients expressed most interest in before-and-after photographs. This study is the first to articulate the plastic surgery patient perspective regarding social media. The findings aim to help plastic surgeons maximize their influence on their target audience.

  14. Can play be defined?

    DEFF Research Database (Denmark)

    Eichberg, Henning

    2015-01-01

    Can play be defined? There is reason to raise critical questions about the established academic demand that at phenomenon – also in humanist studies – should first of all be defined, i.e. de-lineated and by neat lines limited to a “little box” that can be handled. The following chapter develops....... Human beings can very well understand play – or whatever phenomenon in human life – without defining it....

  15. Neuron-glia metabolic coupling and plasticity.

    Science.gov (United States)

    Magistretti, Pierre J

    2006-06-01

    The coupling between synaptic activity and glucose utilization (neurometabolic coupling) is a central physiological principle of brain function that has provided the basis for 2-deoxyglucose-based functional imaging with positron emission tomography (PET). Astrocytes play a central role in neurometabolic coupling, and the basic mechanism involves glutamate-stimulated aerobic glycolysis; the sodium-coupled reuptake of glutamate by astrocytes and the ensuing activation of the Na-K-ATPase triggers glucose uptake and processing via glycolysis, resulting in the release of lactate from astrocytes. Lactate can then contribute to the activity-dependent fuelling of the neuronal energy demands associated with synaptic transmission. An operational model, the 'astrocyte-neuron lactate shuttle', is supported experimentally by a large body of evidence, which provides a molecular and cellular basis for interpreting data obtained from functional brain imaging studies. In addition, this neuron-glia metabolic coupling undergoes plastic adaptations in parallel with adaptive mechanisms that characterize synaptic plasticity. Thus, distinct subregions of the hippocampus are metabolically active at different time points during spatial learning tasks, suggesting that a type of metabolic plasticity, involving by definition neuron-glia coupling, occurs during learning. In addition, marked variations in the expression of genes involved in glial glycogen metabolism are observed during the sleep-wake cycle, with in particular a marked induction of expression of the gene encoding for protein targeting to glycogen (PTG) following sleep deprivation. These data suggest that glial metabolic plasticity is likely to be concomitant with synaptic plasticity.

  16. Roles of the plasticity regions of Helicobacter pylori in gastroduodenal pathogenesis.

    Science.gov (United States)

    Yamaoka, Yoshio

    2008-05-01

    Putative virulence genes of Helicobacter pylori are generally classified into three categories: strain-specific genes, phase-variable genes and genes with variable structures/genotypes. Among these, there has recently been considerable interest in strain-specific genes found outside of the cag pathogenicity island, especially genes in the plasticity regions. Nearly half of the strain-specific genes of H. pylori are located in the plasticity regions in strains 26695 and J99. Strain HPAG1, however, seems to lack a typical plasticity region; instead it has 43 HPAG1-specific genes which are either undetectable or incompletely represented in the genomes of strains 26695 and J99. Recent studies showed that certain genes or combination of genes in this region may play important roles in the pathogenesis of H. pylori-associated gastroduodenal diseases. Most previous studies have focused on the plasticity region in strain J99 (jhp0914-jhp0961) and the jhp0947 gene and the duodenal ulcer promoting (dupA) gene are good candidate markers for gastroduodenal diseases although there are some paradoxical findings. The jhp0947 gene is reported to be associated with an increased risk of both duodenal ulcers and gastric cancers, whereas the dupA gene, which encompasses jhp0917 and jhp0918, is reported to be associated with an increased risk of duodenal ulcers and protection against gastric cancers. In addition, recent studies showed that approximately 10-30 % of clinical isolates possess a 16.3 kb type IV secretion apparatus (tfs3) in the plasticity region. Studies on the plasticity region have only just begun, and further investigation is necessary to elucidate the roles of genes in this region in gastroduodenal pathogenesis.

  17. The Role of Neuromodulators in Cortical Plasticity. A Computational Perspective

    Science.gov (United States)

    Pedrosa, Victor; Clopath, Claudia

    2017-01-01

    Neuromodulators play a ubiquitous role across the brain in regulating plasticity. With recent advances in experimental techniques, it is possible to study the effects of diverse neuromodulatory states in specific brain regions. Neuromodulators are thought to impact plasticity predominantly through two mechanisms: the gating of plasticity and the upregulation of neuronal activity. However, the consequences of these mechanisms are poorly understood and there is a need for both experimental and theoretical exploration. Here we illustrate how neuromodulatory state affects cortical plasticity through these two mechanisms. First, we explore the ability of neuromodulators to gate plasticity by reshaping the learning window for spike-timing-dependent plasticity. Using a simple computational model, we implement four different learning rules and demonstrate their effects on receptive field plasticity. We then compare the neuromodulatory effects of upregulating learning rate versus the effects of upregulating neuronal activity. We find that these seemingly similar mechanisms do not yield the same outcome: upregulating neuronal activity can lead to either a broadening or a sharpening of receptive field tuning, whereas upregulating learning rate only intensifies the sharpening of receptive field tuning. This simple model demonstrates the need for further exploration of the rich landscape of neuromodulator-mediated plasticity. Future experiments, coupled with biologically detailed computational models, will elucidate the diversity of mechanisms by which neuromodulatory state regulates cortical plasticity. PMID:28119596

  18. A Conservative Formulation for Plasticity

    Science.gov (United States)

    1992-01-01

    concepts that apply to a broad class of macroscopic models: plastic deformation and plastic flow rule. CONSERVATIVE PLASTICITY 469 3a. Plastic Defrrnation...temperature. We illustrate these concepts with a model that has been used to describe high strain-rate plastic flow in metals [11, 31, 32]. In the case...JOURDREN, AND P. VEYSSEYRE. Un Modele ttyperelastique- Plastique Euldrien Applicable aux Grandes Dtformations: Que/ques R~sultats 1-D. preprint, 1991. 2. P

  19. ECM remodeling and its plasticity

    Science.gov (United States)

    Feng, Jingchen; Jones, Christopher A. R.; Cibula, Matthew; Mao, Xiaoming; Sander, Leonard M.; Levine, Herbert; Sun, Bo

    The mechanical interactions between cells and Extracellular Matrix (ECM) are of great importance in many cellular processes. These interactions are reciprocal, i.e. contracting cells pull and reorganize the surrounding matrix, while the remodeled matrix feeds back to regulate cell activities. Recent experiments show in collagen gels with densely distributed cells, aligned fiber bundles are formed in the direction between neighboring cells. Fibers flow into the center region between contracting cell pairs in this process, which causes the concentration of fibers in the fiber bundles to become significantly enhanced. Using an extended lattice-based model, we show that viscoelasticity plays an essential role in ECM remodeling and contributes to the enhanced concentration in fiber bundles. We further characterize ECM plasticity within our model and verify our results with rheometer experiments.

  20. A novel U-bent plastic optical fibre local surface plasmon resonance sensor based on a graphene and silver nanoparticle hybrid structure

    International Nuclear Information System (INIS)

    Jiang, Shouzhen; Li, Zhe; Zhang, Chao; Gao, Saisai; Li, Zhen; Li, Chonghui; Yang, Cheng; Liu, Mei; Qiu, Hengwei; Liu, Yanjun

    2017-01-01

    In this work, we have presented a novel local surface plasmon resonance (LSPR) sensor based on the U-bent plastic optical fibre (U-POF). Firstly, a layer of discontinuous silver (Ag) thin film was deposited on the U-POF and then the Ag film was covered by a layer of cladding synthesized by polyvinyl alcohol (PVA), graphene and silver nanoparticles forming the PVA/G/AgNPs@Ag film. The normalized transmittance spectrum of the LSPR sensor have been collected in a range of the refractive index (RI) from 1.330 to 1.3657 in ethanol solution, and 700.3 nm/RIU sensitivity of the developed LSPR sensor has been demonstrated. By experiments, we demonstrated that the graphene could improve the sensitivity of the LSPR sensor and delay the oxidation process of the AgNPs effectively to keep the stability of the LSPR sensor. The LSPR sensor also exhibited good sensitivity and linearity in the detection of glucose solutions. This work shows that the developed LSPR sensor may have promising applications in biosensing. (paper)

  1. Strength analyses of containment steel liner at the plasticity instability

    International Nuclear Information System (INIS)

    Klyashchitskij, V.I.; Golyakov, V.I.; Kostylev, V.I.; Margolin, B.Z.

    2003-01-01

    The steel liner of NPP containment plays the important role of a leak-tight contour preventing the possible releases of radioactive substances beyond the boundaries of the reactor building. However, so far in many cases an assessment of strain-stress state of the liner having initial imperfections of the shape was made with approximate methods. A new methodology for the analysis of the liner at the plasticity instability was developed at Atomenergoproekt institute in cooperation with specialists from other agencies. The methodology is based on code 'Termit'. Assessment of the critical strain was made taking into account possible presence of one or two defects: construction undercut or crack-like defect in a weld. On the base of the real structure analyses under any combinations of quasi-static loads the algorithm was developed for the computation of the liner. (author)

  2. Numerical Investigation of Plastic Deformation in Two-turn Equal Channel Angular Extrusion

    Directory of Open Access Journals (Sweden)

    A. Mitsak

    2014-12-01

    Full Text Available There has been a number of investigations in recent years reporting on the structure and properties of materials deformed to super plastic deformation (SPD. During SPD new textures can be formed and abnormal characteristics are displayed, attracting a growing research interest.¶ Equal channel angular extrusion (ECAE is a method often used to obtain large plastic strains. However, according to experimental results, there is a large tensile stress in the sample during deformation, which may lead in some cases, to cracking in metallic alloys and large curvature in polymeric materials. In order to overcome these drawbacks, the ECAE process can be conducted at high temperatures. But this contributes significantly to a decreased level of plastic deformation induced in the sample. Hence, a tool with multi-pass seems to be a very appropriate solution. In this paper, a new geometry die composed of two elbows has been simulated by finite element method aiming to provide an insight into the mechanisms of deformation and to determine the optimum geometry of the tool. The numerical results show that the length and the section of the second channel play a significant role on the homogeneity of the plastic strain distribution. It has been found that good homogeneity was obtained when the second channel has the same section as that of the entrance and the exit channels and with a length equal to three times of its width.

  3. A light-stimulated synaptic transistor with synaptic plasticity and memory functions based on InGaZnO{sub x}–Al{sub 2}O{sub 3} thin film structure

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. K.; Chen, T. P., E-mail: echentp@ntu.edu.sg; Liu, P.; Zhang, Q. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Hu, S. G. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Liu, Y. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Lee, P. S. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2016-06-28

    In this work, a synaptic transistor based on the indium gallium zinc oxide (IGZO)–aluminum oxide (Al{sub 2}O{sub 3}) thin film structure, which uses ultraviolet (UV) light pulses as the pre-synaptic stimulus, has been demonstrated. The synaptic transistor exhibits the behavior of synaptic plasticity like the paired-pulse facilitation. In addition, it also shows the brain's memory behaviors including the transition from short-term memory to long-term memory and the Ebbinghaus forgetting curve. The synapse-like behavior and memory behaviors of the transistor are due to the trapping and detrapping processes of the holes, which are generated by the UV pulses, at the IGZO/Al{sub 2}O{sub 3} interface and/or in the Al{sub 2}O{sub 3} layer.

  4. The plasticity of clays

    Science.gov (United States)

    Group, F.F.

    1905-01-01

    (1) Sand injures plasticity little at first because the grains are suspended in a plastic mass. It is only when grains are abundant enough to come in contact with their neighbors, that the effect becomes serious, and then both strength and amount of possible flow are injured. (2) Certain rare organic colloids increase the plasticity by rendering the water viscous. (3) Fineness also tends to increase plasticity. (4) Plane surfaces (plates) increase the amount of possible flow. They also give a chance for lubrication by thinner films, thus increasing the friction of film, and the strength of the whole mass. The action of plates is thus twofold ; but fineness may be carried to such an extent as to break up plate-like grains into angular fragments. The beneficial effects of plates are also decreased by the fact that each is so closely surrounded by others in the mass. (5) Molecular attraction is twofold in increasing plasticity. As the attraction increases, the coherence and strength of the mass increase, and the amount of possible deformation before crumbling also increases. Fineness increases this action by requiring more water. Colloids and crystalloids in solution may also increase the attraction. It is thus seen to be more active than any other single factor.

  5. Plastics control paraffin buildup

    Energy Technology Data Exchange (ETDEWEB)

    1965-06-01

    Paraffin buildup in producing oil wells has been virtually eliminated by the use of plastic-coated sucker rods. The payout of the plasticing process is generally reached in less than a year, and the paraffin buildup may be inhibited for 10 yr or longer. Most of the plants applying plastic coatings to sucker rods are now fully automated, though a few still offer the hand-sprayed coating that some operators prefer. The several steps involved are described. The ideal plastic for the job is resistant to chemicals at high and low temperatures, flexible, has good adhesion, abrasion resistance, impact resistance, and a smooth glossy finish. The phenol aldehyde and epoxy resins presently offered by the industry fulfill these specifications very well; the multicoating and multibaking techniques improve their performance. Due to wide variations in the severity of the paraffin problem from one oil field to another, there is no general rule to estimate the possible savings from using plastic-coated sucker rods. The process, however, does appear to do a remarkable job in controlling paraffin buildup wherever it is a problem in producing oil by pump.

  6. Playing and gaming

    DEFF Research Database (Denmark)

    Karoff, Helle Skovbjerg; Ejsing-Duun, Stine; Hanghøj, Thorkild

    2013-01-01

    The paper develops an approach of playing and gaming activities through the perspective of both activities as mood activities . The point of departure is that a game - is a tool with which we, through our practices, achieve different moods. This based on an empirical study of children's everyday...... lives, where the differences emerge through actual practices, i.e. through the creation of meaning in the specific situations. The overall argument is that it is not that important whether it is a playing or a gaming activity - it is however crucial to be aware of how moods occur and what their optimal...... dimensions: practices and moods. Practice is the concept of all the doing in the activities. Moods are the particular concept of sense and feeling of being, which is what we are drawn to when we are playing or gaming....

  7. To play is necessary

    Directory of Open Access Journals (Sweden)

    Angela Vargas

    2008-05-01

    Full Text Available This work tries to contemplate on playing, leaving of the observations on the children's games accomplished during the apprenticeship and the articulation of those with some theoretical ones that have been dedicating if to the study of the game, of the childhood and of the Infantile Education. It was possible, through the apprenticeship registrations and of the observations to live many moments in that the two groups, 3A and 3B, they played incorporating objects and creating characters in your games. He/she gave way, we sought focar the game of the do-of-bill, contemplating on your importance for the children in the first childhood, and that possibilities she brings us in the amplification of the infantile experiences. Another important aspect in this article is to contemplate on the teacher's practice in the Infantile Education, and, through our observations on playing of the children noticed the teachers' involvement in the children's games.

  8. Reaction-diffusion-like formalism for plastic neural networks reveals dissipative solitons at criticality

    Science.gov (United States)

    Grytskyy, Dmytro; Diesmann, Markus; Helias, Moritz

    2016-06-01

    Self-organized structures in networks with spike-timing dependent synaptic plasticity (STDP) are likely to play a central role for information processing in the brain. In the present study we derive a reaction-diffusion-like formalism for plastic feed-forward networks of nonlinear rate-based model neurons with a correlation sensitive learning rule inspired by and being qualitatively similar to STDP. After obtaining equations that describe the change of the spatial shape of the signal from layer to layer, we derive a criterion for the nonlinearity necessary to obtain stable dynamics for arbitrary input. We classify the possible scenarios of signal evolution and find that close to the transition to the unstable regime metastable solutions appear. The form of these dissipative solitons is determined analytically and the evolution and interaction of several such coexistent objects is investigated.

  9. General game playing

    CERN Document Server

    Genesereth, Michael

    2014-01-01

    General game players are computer systems able to play strategy games based solely on formal game descriptions supplied at ""runtime"" (n other words, they don't know the rules until the game starts). Unlike specialized game players, such as Deep Blue, general game players cannot rely on algorithms designed in advance for specific games; they must discover such algorithms themselves. General game playing expertise depends on intelligence on the part of the game player and not just intelligence of the programmer of the game player.GGP is an interesting application in its own right. It is intell

  10. Motivation, Creativity, Play & Learning

    DEFF Research Database (Denmark)

    Petersson, Eva

    2005-01-01

    on their needs and desires. This paper presents results from SoundScapes body of research which is utilising technology in assistive (re)habilitation from Virtual Interactive Space (VIS); furthermore the paper describes what emerges in play scenarios that utilise enabling technology. The involved study exhibits...... implementation of robotic physical movement synchronously manipulated from sourced data movement information of a human. SoundScapes is a concept based on non-verbal communication and stimulation through interactive play with sounds and images, which is being realised in the production of a non-wearable sensor...

  11. Nicotinic mechanisms influencing synaptic plasticity in the hippocampus

    Institute of Scientific and Technical Information of China (English)

    Andon Nicholas PLACZEK; Tao A ZHANG; John Anthony DANI

    2009-01-01

    Nicotinic acetylcholine receptors (nAChRs) are expressed throughout the hippocampus, and nicotinic signaling plays an important role in neuronal function. In the context of learning and memory related behaviors associated with hippocampal function, a potentially significant feature of nAChR activity is the impact it has on synaptic plasticity. Synaptic plasticity in hippocampal neurons has long been considered a contributing cellular mechanism of learning and memory. These same kinds of cellular mechanisms are a factor in the development of nicotine addiction. Nicotinic signaling has been demonstrated by in vitro studies to affect synaptic plasticity in hippocampal neurons via multiple steps, and the signaling has also been shown to evoke synaptic plasticity in vivo. This review focuses on the nAChRs subtypes that contribute to hippocampal synaptic plasticity at the cellular and circuit level. It also considers nicotinic influences over long-term changes in the hippocampus that may contribute to addiction.

  12. [Involvement of aquaporin-4 in synaptic plasticity, learning and memory].

    Science.gov (United States)

    Wu, Xin; Gao, Jian-Feng

    2017-06-25

    Aquaporin-4 (AQP-4) is the predominant water channel in the central nervous system (CNS) and primarily expressed in astrocytes. Astrocytes have been generally believed to play important roles in regulating synaptic plasticity and information processing. However, the role of AQP-4 in regulating synaptic plasticity, learning and memory, cognitive function is only beginning to be investigated. It is well known that synaptic plasticity is the prime candidate for mediating of learning and memory. Long term potentiation (LTP) and long term depression (LTD) are two forms of synaptic plasticity, and they share some but not all the properties and mechanisms. Hippocampus is a part of limbic system that is particularly important in regulation of learning and memory. This article is to review some research progresses of the function of AQP-4 in synaptic plasticity, learning and memory, and propose the possible role of AQP-4 as a new target in the treatment of cognitive dysfunction.

  13. [The behavior of fiber-reinforced plastics during laser cutting].

    Science.gov (United States)

    Emmrich, M; Levsen, K; Trasser, F J

    1992-06-01

    The pattern of the organic emissions, which are produced by processing of fibre reinforced plastics (epoxy resins reinforced by aramid and glass fibres and phenol resins reinforced by aramid fibre) with laser beam was studied and the concentrations of the main components determined. Despite the application of plastic materials with different chemical structures, the observed patterns are very similar. Mainly aromatic hydrocarbons are emitted, especially benzene and toluene, as well as some heteroatom-containing aromatic hydrocarbons (e.g. phenol). By use of oxygen as process gas the emissions during cutting of glass fibre reinforced plastics can be reduced, while they will be constantly high with aramid fibre reinforced plastics.

  14. The plastic brain: neoliberalism and the neuronal self.

    Science.gov (United States)

    Pitts-Taylor, Victoria

    2010-11-01

    Neuroscience-based representations and practices of the brain aimed at lay populations present the brain in ways that both affirm biological determinism and also celebrate plasticity, or the brain's ability to change structure and function. Popular uses of neuroscientific theories of brain plasticity are saturated with a neoliberal vision of the subject. Against more optimistic readings of plasticity, I view the popular deployment of plasticity through the framework of governmentality. I describe how popular brain discourse on plasticity opens up the brain to personal techniques of enhancement and risk avoidance, and how it promotes a neuronal self. I situate brain plasticity in a context of biomedical neoliberalism, where the engineering and modification of biological life is positioned as essential to selfhood and citizenship.

  15. Investigation of the Structure, Optical and Electrical Properties of Lithium Perchlorate Doped Polyaniline Composite: Aloe Vera Used as a Bio-Plasticizer

    Science.gov (United States)

    Yesappa, L.; Niranjana, M.; Ashokkumar, S. P.; Vijeth, H.; Sharanappa, Chapi; Raghu, S.; Devendrappa, H.

    2017-12-01

    Bio-plasticizer based polyaniline (PANI)/lithium perchlorate (LiClO4) composites were synthesized by the facile in situ method. The composites were characterized using the Fourier transform infrared spectroscopy (FT-IR) to identify the chemical interactions. A band appeared at 1502 cm-1 due to the presence of the -H2CO- group and CH2 scissor mode vibration for the PAL15% composite. This considerable change in the morphology of LiClO4 homogeneous dispersion in a PANI matrix was investigated by scanning electron microscopy (SEM). The UV-Visible absorption (UV-Vis) showed 300-400 nm attributed to the π- π* transition and exhibited a red shift from 535 nm to 617 nm in the visible region, indicating a decrease in band gap. The variations in dielectric constant with the addition of lithium perchlorate (LiClO4) at different temperatures and in the frequency range of 20 Hz-1 MHz were assessed through impedance analysis. The temperature dependent electrical conductivity increased with increasing temperature as well as dopant concentration. High conductivity of 1.41 × 10-3 S/cm corresponding to activation energy of 0.02 eV and 2.95 eV optical band gap for 15 wt.% of LiClO4 concentration was observed. The cyclic voltammetry measurement revealed a typical rectangular shape of the integral area, suggesting that the composite has strong electrochemical strength and is a possible candidate for electrochemical super capacitor and solar cell applications.

  16. Play and Power

    DEFF Research Database (Denmark)

    The power of play, so central to psychoanalytic theory and practice, is conjoined to the social psychological or socio-politically coloured concept of power, giving rise to many fruitful discussions of how these concepts manifest themselves in clinical work with children, groups and adults...

  17. Play's Importance in School

    Science.gov (United States)

    Sandberg, Anette; Heden, Rebecca

    2011-01-01

    The purpose of this study is to contribute knowledge on and gain an understanding of elementary school teachers' perspectives on the function of play in children's learning processes. The study is qualitative with a hermeneutical approach and has George Herbert Mead as a theoretical frame of reference. Interviews have been carried out with seven…

  18. Play framework essentials

    CERN Document Server

    Richard-Foy, Julien

    2014-01-01

    This book targets Java and Scala developers who already have some experience in web development and who want to master Play framework quickly and efficiently. This book assumes you have a good level of knowledge and understanding of efficient Java and Scala code.

  19. Efficacy of play therapy

    African Journals Online (AJOL)

    User

    Life-skills of Children Under Difficult Circumstances: The. Case of Two ... Goodman's Strengths and Difficulties Questionnaire-a standardized instrument) were obtained from 17 ... From a developmental point of view, play ... preventing mild problems becoming worse, .... records) and a socially withdrawn child-for example ...

  20. The Activity of Play

    DEFF Research Database (Denmark)

    Pichlmair, Martin

    This paper presents Activity Theory as a framework for understanding the action of playing games with the intention of building a foundation for the creation of new game design tools and methods. Activity Theory, an epistemological framework rooted in Soviet psychology of the first half of the 20...

  1. stage/page/play

    DEFF Research Database (Denmark)

    context. Contributors: Per Brask, Dario Fo, Jette Barnholdt Hansen, Pil Hansen, Sven Åke Heed, Ulla Kallenbach, Sofie Kluge, Annelis Kuhlmann, Kela Kvam, Anna Lawaetz, Bent Flemming Nielsen, Franco Perrelli, Magnus Tessing Schneider, Antonio Scuderi. stage/page/play is published as a festschrift...

  2. Investigation into Plastic Cards

    Directory of Open Access Journals (Sweden)

    Neringa Stašelytė

    2015-03-01

    Full Text Available The article examines the strength of laminating plastic cards at different lamination temperatures. For investigation purposes, two types of plastic substrate and films have been used. Laminate strength has been tested (CMYK to establish the impact of colours on the strength of laminate. The paper compares inks supplied by two different producers. The colour characteristics of CIE L*a*b* space before and after the lamination process have been found. According to lamination strength and characteristics of the colours, the most suitable inks, temperature and films have been chosen.

  3. Joining by plastic deformation

    DEFF Research Database (Denmark)

    Mori, Ken-ichiro; Bay, Niels; Fratini, Livan

    2013-01-01

    As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating opportuni......As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating...

  4. Human Maternal Brain Plasticity: Adaptation to Parenting

    Science.gov (United States)

    Kim, Pilyoung

    2016-01-01

    New mothers undergo dynamic neural changes that support positive adaptation to parenting and the development of mother-infant relationships. In this article, I review important psychological adaptations that mothers experience during pregnancy and the early postpartum period. I then review evidence of structural and functional plasticity in human…

  5. BDNF-induced local protein synthesis and synaptic plasticity.

    Science.gov (United States)

    Leal, Graciano; Comprido, Diogo; Duarte, Carlos B

    2014-01-01

    Brain-derived neurotrophic factor (BDNF) is an important regulator of synaptic transmission and long-term potentiation (LTP) in the hippocampus and in other brain regions, playing a role in the formation of certain forms of memory. The effects of BDNF in LTP are mediated by TrkB (tropomyosin-related kinase B) receptors, which are known to be coupled to the activation of the Ras/ERK, phosphatidylinositol 3-kinase/Akt and phospholipase C-γ (PLC-γ) pathways. The role of BDNF in LTP is best studied in the hippocampus, where the neurotrophin acts at pre- and post-synaptic levels. Recent studies have shown that BDNF regulates the transport of mRNAs along dendrites and their translation at the synapse, by modulating the initiation and elongation phases of protein synthesis, and by acting on specific miRNAs. Furthermore, the effect of BDNF on transcription regulation may further contribute to long-term changes in the synaptic proteome. In this review we discuss the recent progress in understanding the mechanisms contributing to the short- and long-term regulation of the synaptic proteome by BDNF, and the role in synaptic plasticity, which is likely to influence learning and memory formation. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. The expression of plasticity-related genes in an acute model of stress is modulated by chronic desipramine in a time-dependent manner within medial prefrontal cortex.

    Science.gov (United States)

    Nava, Nicoletta; Treccani, Giulia; Müller, Heidi Kaastrup; Popoli, Maurizio; Wegener, Gregers; Elfving, Betina

    2017-01-01

    It is well established that stress plays a major role in the pathogenesis of neuropsychiatric diseases. Stress-induced alteration of synaptic plasticity has been hypothesized to underlie the morphological changes observed by neuroimaging in psychiatric patients in key regions such as hippocampus and prefrontal cortex (PFC). We have recently shown that a single acute stress exposure produces significant short-term alterations of structural plasticity within medial PFC. These alterations were partially prevented by previous treatment with chronic desipramine (DMI). In the present study we evaluated the effects of acute Foot-shock (FS)-stress and pre-treatment with the traditional antidepressant DMI on the gene expression of key regulators of synaptic plasticity and structure. Expression of Homer, Shank, Spinophilin, Densin-180, and the small RhoGTPase related gene Rac1 and downstream target genes, Limk1, Cofilin1 and Rock1 were investigated 1 day (1d), 7 d and 14d after FS-stress exposure. We found that DMI specifically increases the short-term expression of Spinophilin, as well as Homer and Shank family genes, and that both acute stress and DMI exert significant long-term effects on mRNA levels of genes involved in spine plasticity. These findings support the knowledge that acute FS stress and antidepressant treatment induce both rapid and sustained time-dependent alterations in structural components of synaptic plasticity in rodent medial PFC. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  7. Visual attentional load influences plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Hall, Michelle G; Lye, Hayley F; Sale, Martin V; Fenlon, Laura R; Carroll, Timothy J; Riek, Stephan; Mattingley, Jason B

    2012-05-16

    Neural plasticity plays a critical role in learning, memory, and recovery from injury to the nervous system. Although much is known about the physical and physiological determinants of plasticity, little is known about the influence of cognitive factors. In this study, we investigated whether selective attention plays a role in modifying changes in neural excitability reflecting long-term potentiation (LTP)-like plasticity. We induced LTP-like effects in the hand area of the human motor cortex using transcranial magnetic stimulation (TMS). During the induction of plasticity, participants engaged in a visual detection task with either low or high attentional demands. Changes in neural excitability were assessed by measuring motor-evoked potentials in a small hand muscle before and after the TMS procedures. In separate experiments plasticity was induced either by paired associative stimulation (PAS) or intermittent theta-burst stimulation (iTBS). Because these procedures induce different forms of LTP-like effects, they allowed us to investigate the generality of any attentional influence on plasticity. In both experiments reliable changes in motor cortex excitability were evident under low-load conditions, but this effect was eliminated under high-attentional load. In a third experiment we investigated whether the attentional task was associated with ongoing changes in the excitability of motor cortex, but found no difference in evoked potentials across the levels of attentional load. Our findings indicate that in addition to their role in modifying sensory processing, mechanisms of attention can also be a potent modulator of cortical plasticity.

  8. The Art of Playful Mobility in Museums

    DEFF Research Database (Denmark)

    Froes, Isabel Cristina G.; Walker, Kevin

    2012-01-01

    Many of us interact with other people in online games and social networks, through multiple digital devices. But harnessing playful and mobile activities for museum learning is mostly undeveloped. In this chapter we explore play as a structure to support visitor learning, drawing from internation...

  9. Elastic-plastic-creep analysis of shells

    International Nuclear Information System (INIS)

    Pai, D.H.

    1979-01-01

    This paper presents the recent experience of a designer/fabricator of nuclear heat transport components in the area of elastic-plastic-creep analysis of shell-like structures. A brief historical perspective is first given to highlight the evolution leading to the present industry practice. The ASME elevated temperature design criteria will be discussed followed by examples of actual computations performed to support the design/analysis and fabrication of a breeder reactor component in which a substantial amount of elastic-plastic-creep analysis was performed. Mathematical challenges encountered by the design analyst in these problems will be highlighted. Developmental needs and future trends will then be given

  10. Play or science?

    DEFF Research Database (Denmark)

    Lieberoth, Andreas; Pedersen, Mads Kock; Sherson, Jacob

    2015-01-01

    Crowdscience games may hold unique potentials as learning opportunities compared to games made for fun or education. They are part of an actual science problem solving process: By playing, players help scientists, and thereby interact with real continuous research processes. This mixes the two...... worlds of play and science in new ways. During usability testing we discovered that users of the crowdscience game Quantum Dreams tended to answer questions in game terms, even when directed explicitly to give science explanations. We then examined these competing frames of understanding though a mixed...... correlational and grounded theory analysis. This essay presents the core ideas of crowdscience games as learning opportunities, and reports how a group of players used “game”, “science” and “conceptual” frames to interpret their experience. Our results suggest that oscillating between the frames instead...

  11. Understanding Games as Played

    DEFF Research Database (Denmark)

    Leino, Olli Tapio

    2009-01-01

    Researchers interested in player’s experience would assumedly, across disciplines, agree that the goal behind enquiries into player’s experience is to understand the how games’ features end up affecting the player’s experience. Much of the contemporary interdisciplinary research into player......’s experience leans toward the empirical-scientific, in the forms (neuro)psychology, sociology and cognitive science, to name a few. In such approaches, for example demonstrating correlation between physiological symptoms and an in-game event may amount to ‘understanding’. However, the experience of computer...... game play is a viable topic also for computer game studies within the general tradition of humanities. In such context, the idea of ‘understanding an experience’ invites an approach focusing on the experienced significance of events and objects within computer game play. This focus, in turn, suggests...

  12. Ravens at Play

    Directory of Open Access Journals (Sweden)

    Deborah Bird Rose

    2011-09-01

    Full Text Available  ‘We were driving through Death Valley, an American-Australian and two Aussies, taking the scenic route from Las Vegas to Santa Cruz.’ This multi-voiced account of multispecies encounters along a highway takes up the challenge of playful and humorous writing that is as well deeply serious and theoretically provocative. Our travels brought us into what Donna Haraway calls the contact zone: a region of recognition and response. The contact zone is a place of significant questions: ‘Who are you, and so who are we? Here we are, and so what are we to become?’ Events were everything in this ecology of play, in which the movements of all the actors involved the material field in its entirety. We were brought into dances of approach and withdrawal, dances emerging directly, to paraphrase Brian Massumi, from the dynamic relation between a myriad of charged particles.

  13. Playful Collaboration (or Not)

    DEFF Research Database (Denmark)

    Bogers, Marcel

    2011-01-01

    This paper explores how games and play, which are deeply rooted in human beings as a way to learn and interact, can be used to teach certain concepts and practices related to open collaborative innovation. We discuss how playing games can be a source of creativity, imagination and fun, while it can...... also be conducive to deep learning. As such, a game can engage different dimensions of learning and embed elements of active, collaborative, cooperative and problem-based learning. Building on this logic, we present an exploratory case study of the use of a particular board game in a class of a course...... collaboration at the cost of individual performance and possible long-term collective performance as well....

  14. Play. Learn. Innovate

    DEFF Research Database (Denmark)

    Sproedt, Henrik

    study were to better understand the theoretical foundations and practical implications of complex social interaction in organizational innovation settings. As I did not find any existing models or hypotheses that I was interested in testing I set out to discover how I could grasp complex social...... evidence that play and games could be interesting perspectives to take in order to understand complex social interaction. I come to the conclusion that – in innovation settings – the social dynamics that affect the process are essentially about transformation of knowledge across boundaries. I propose......„Play. Learn. Innovate. – Grasping the Social Dynamics of Participatory Innovation“ the title of this thesis describes how the complex interplay of unexpected events led to some burning questions and eventually to this thesis, which one could call an innovation*1*. During several years...

  15. Creativity and Playfulness

    DEFF Research Database (Denmark)

    Ejsing-Duun, Stine; Skovbjerg, Helle Marie

    2015-01-01

    Abstract: This article explores how student behavior and interactions change when teachers use “producing games” as a primary pedagogical strategy (Papert, 1980; Ejsing-Duun and Karoff, 2014). Based on student and teacher actions and responses, as well as on students' production—observed during f...... fieldwork—this paper emphasizes the importance of understanding how students explore creativity and playfulness while producing in learning situations....

  16. Plastic flashtube chambers

    International Nuclear Information System (INIS)

    Frisken, W.R.

    1977-01-01

    A brief discussion is given of the use and operation of plastic flashtube chambers. Gas leaks, electric pulsing, the glow discharge, and readout methods are considered. Three distinct problems with high rate applications deal with resolving time, dead time, and polarization/neutralization of the chamber

  17. Plastic Surgery: Tackling Misconceptions

    African Journals Online (AJOL)

    will succeed. First impressions tend to last, and if young people's first impression of plastic surgeons is that they spend much of their time doing cosmetic surgery then this is a first impression that might be long ... Res 2014;4 Suppl S3:169‑70. Access this article online. Quick Response Code: Website: www.amhsr.org. DOI:.

  18. Biobased Plastics 2012

    NARCIS (Netherlands)

    Bolck, C.H.; Ravenstijn, J.; Molenveld, K.; Harmsen, P.F.H.

    2011-01-01

    Dit boek geeft inzicht in de huidige op de markt verkrijgbare biobased plastics en de te verwachten ontwikkelingen. Er wordt gekeken naar zowel thermoplastische als thermohardende materialen. Het boek biedt inzicht in de productie, verwerking en eigenschappen van de verschillende types. Daarnaast

  19. New plastic recycling technology

    Science.gov (United States)

    Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy de...

  20. Reliability of Plastic Slabs

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    1989-01-01

    In the paper it is shown how upper and lower bounds for the reliability of plastic slabs can be determined. For the fundamental case it is shown that optimal bounds of a deterministic and a stochastic analysis are obtained on the basis of the same failure mechanisms and the same stress fields....