WorldWideScience

Sample records for muscle pattern formation

  1. Pattern Formation

    Science.gov (United States)

    Hoyle, Rebecca

    2006-03-01

    From the stripes of a zebra and the spots on a leopard's back to the ripples on a sandy beach or desert dune, regular patterns arise everywhere in nature. The appearance and evolution of these phenomena has been a focus of recent research activity across several disciplines. This book provides an introduction to the range of mathematical theory and methods used to analyse and explain these often intricate and beautiful patterns. Bringing together several different approaches, from group theoretic methods to envelope equations and theory of patterns in large-aspect ratio-systems, the book also provides insight behind the selection of one pattern over another. Suitable as an upper-undergraduate textbook for mathematics students or as a fascinating, engaging, and fully illustrated resource for readers in physics and biology, Rebecca Hoyle's book, using a non-partisan approach, unifies a range of techniques used by active researchers in this growing field. Accessible description of the mathematical theory behind fascinating pattern formation in areas such as biology, physics and materials science Collects recent research for the first time in an upper level textbook Features a number of exercises - with solutions online - and worked examples

  2. Patterns of superficial fibre formation in the European pearlfish (Rutilus frisii meidingeri) provide a general template for slow muscle development in teleost fish.

    Science.gov (United States)

    Stoiber, W; Haslett, J R; Goldschmid, A; Sänger, A M

    1998-06-01

    The debate about the pattern of muscle formation in teleost fish has recently been heightened in the literature. Here we examine superficial muscle development in the pearlfish, a cyprinid endemic to a small area of Central Europe, and uninfluenced by economic interest and breeding. Using light and electron microscopy, histochemistry and immunohistochemistry techniques, we report that: (1) Superficial fibre precursors originate close to the notochord, are part of the same cell population as the so-called muscle pioneer cells, and are transferred laterally to end up at the surface of the myotome. (2) Superficial fibre maturation is exceptionally rapid. Structural and enzymatic functionality is attained at a time when prospective deep fibres have not passed beyond the early myotube state. This strong contrast weakens as the embryo develops. (3) Apart from the muscle pioneers, the superficial fibres appear to be capable of functioning before they receive any direct innervation, implying that signals are transferred to these fibres via cell-to-cell junctions. We suggest that the capability of rapid superficial fibre maturation is a rather general feature among teleosts and may aid pre-hatch survival under a variable environment. Our results indicate that muscle formation in teleost fish may follow a common basic pattern that is open to considerable ontogenetic and phylogenetic modification in response to habitat conditions.

  3. Pattern Formation in Hydrozoa

    Science.gov (United States)

    Berking, Stefan

    The fresh water polyp Hydra is famous for its ability to regenerate missing structures. Even aggregates of single cells transform eventually into normally shaped animals. This indicates a communication within the tissue and within the aggregates which determines the spatial pattern of gene expression. Such pattern-forming systems are thought to play a decisive role in the control of self-organization during embryogenesis. Marine and fresh water hydrozoa appear to allow an access to such a system. Although the molecular components are still mostly unknown, the regulatory properties of the pattern-forming system are increasingly well understood, and this may help eventually to identify the components involved.

  4. Sarcomeric Pattern Formation by Actin Cluster Coalescence

    Science.gov (United States)

    Friedrich, Benjamin M.; Fischer-Friedrich, Elisabeth; Gov, Nir S.; Safran, Samuel A.

    2012-01-01

    Contractile function of striated muscle cells depends crucially on the almost crystalline order of actin and myosin filaments in myofibrils, but the physical mechanisms that lead to myofibril assembly remains ill-defined. Passive diffusive sorting of actin filaments into sarcomeric order is kinetically impossible, suggesting a pivotal role of active processes in sarcomeric pattern formation. Using a one-dimensional computational model of an initially unstriated actin bundle, we show that actin filament treadmilling in the presence of processive plus-end crosslinking provides a simple and robust mechanism for the polarity sorting of actin filaments as well as for the correct localization of myosin filaments. We propose that the coalescence of crosslinked actin clusters could be key for sarcomeric pattern formation. In our simulations, sarcomere spacing is set by filament length prompting tight length control already at early stages of pattern formation. The proposed mechanism could be generic and apply both to premyofibrils and nascent myofibrils in developing muscle cells as well as possibly to striated stress-fibers in non-muscle cells. PMID:22685394

  5. Sarcomeric pattern formation by actin cluster coalescence.

    Directory of Open Access Journals (Sweden)

    Benjamin M Friedrich

    Full Text Available Contractile function of striated muscle cells depends crucially on the almost crystalline order of actin and myosin filaments in myofibrils, but the physical mechanisms that lead to myofibril assembly remains ill-defined. Passive diffusive sorting of actin filaments into sarcomeric order is kinetically impossible, suggesting a pivotal role of active processes in sarcomeric pattern formation. Using a one-dimensional computational model of an initially unstriated actin bundle, we show that actin filament treadmilling in the presence of processive plus-end crosslinking provides a simple and robust mechanism for the polarity sorting of actin filaments as well as for the correct localization of myosin filaments. We propose that the coalescence of crosslinked actin clusters could be key for sarcomeric pattern formation. In our simulations, sarcomere spacing is set by filament length prompting tight length control already at early stages of pattern formation. The proposed mechanism could be generic and apply both to premyofibrils and nascent myofibrils in developing muscle cells as well as possibly to striated stress-fibers in non-muscle cells.

  6. Understanding Alliance Formation Patterns

    Science.gov (United States)

    2015-12-01

    agreement to open international markets because trade produces security externalities.”131 Gowa explains the necessity to maintain trade among allies by...alone.”135 They present empirical evidence to “ indicate that allies conduct more trade than do non-allies and that the formation of alliances tends to...states to control their trade flows.”138 Morrow et al. indicate that “joint democracy and the 133

  7. Pattern formations and oscillatory phenomena

    CERN Document Server

    Kinoshita, Shuichi

    2013-01-01

    Patterns and their formations appear throughout nature, and are studied to analyze different problems in science and make predictions across a wide range of disciplines including biology, physics, mathematics, chemistry, material science, and nanoscience. With the emergence of nanoscience and the ability for researchers and scientists to study living systems at the biological level, pattern formation research has become even more essential. This book is an accessible first of its kind guide for scientists, researchers, engineers, and students who require a general introduction to thi

  8. Mechanical tension and spontaneous muscle twitching precede the formation of cross-striated muscle in vivo.

    Science.gov (United States)

    Weitkunat, Manuela; Lindauer, Martina; Bausch, Andreas; Schnorrer, Frank

    2017-02-07

    Muscle forces are produced by repetitive stereotyped acto-myosin units called sarcomeres. Sarcomeres are chained into linear myofibrils spanning the entire muscle fiber. In mammalian body muscles, myofibrils are aligned laterally resulting in their typical cross-striated morphology. Despite this detailed textbook knowledge about the adult muscle structure, it is still unclear how cross-striated myofibrils are built in vivo Here, we investigate the morphogenesis of Drosophila abdominal muscles and establish them as in vivo model for cross-striated muscle development. Using live imaging, we find that long immature myofibrils lacking a periodic acto-myosin pattern are built simultaneously in the entire muscle fiber and then align laterally to mature cross-striated myofibrils. Interestingly, laser micro-lesion experiments demonstrate that mechanical tension precedes the formation of the immature myofibrils. Moreover, these immature myofibrils do generate spontaneous Ca(2+) dependent contractions in vivo, which when chemically blocked result in cross-striation defects. Together, these results suggest a myofibrillogenesis model, in which mechanical tension and spontaneous muscle twitchings synchronise the simultaneous self-organisation of different sarcomeric protein complexes to build highly regular cross-striated myofibrils spanning throughout large muscle fibers.

  9. Pattern formations and optimal packing.

    Science.gov (United States)

    Mityushev, Vladimir

    2016-04-01

    Patterns of different symmetries may arise after solution to reaction-diffusion equations. Hexagonal arrays, layers and their perturbations are observed in different models after numerical solution to the corresponding initial-boundary value problems. We demonstrate an intimate connection between pattern formations and optimal random packing on the plane. The main study is based on the following two points. First, the diffusive flux in reaction-diffusion systems is approximated by piecewise linear functions in the framework of structural approximations. This leads to a discrete network approximation of the considered continuous problem. Second, the discrete energy minimization yields optimal random packing of the domains (disks) in the representative cell. Therefore, the general problem of pattern formations based on the reaction-diffusion equations is reduced to the geometric problem of random packing. It is demonstrated that all random packings can be divided onto classes associated with classes of isomorphic graphs obtained from the Delaunay triangulation. The unique optimal solution is constructed in each class of the random packings. If the number of disks per representative cell is finite, the number of classes of isomorphic graphs, hence, the number of optimal packings is also finite.

  10. Magnetic Assisted Colloidal Pattern Formation

    Science.gov (United States)

    Yang, Ye

    Pattern formation is a mysterious phenomenon occurring at all scales in nature. The beauty of the resulting structures and myriad of resulting properties occurring in naturally forming patterns have attracted great interest from scientists and engineers. One of the most convenient experimental models for studying pattern formation are colloidal particle suspensions, which can be used both to explore condensed matter phenomena and as a powerful fabrication technique for forming advanced materials. In my thesis, I have focused on the study of colloidal patterns, which can be conveniently tracked in an optical microscope yet can also be thermally equilibrated on experimentally relevant time scales, allowing for ground states and transitions between them to be studied with optical tracking algorithms. In particular, I have focused on systems that spontaneously organize due to particle-surface and particle-particle interactions, paying close attention to systems that can be dynamically adjusted with an externally applied magnetic or acoustic field. In the early stages of my doctoral studies, I developed a magnetic field manipulation technique to quantify the adhesion force between particles and surfaces. This manipulation technique is based on the magnetic dipolar interactions between colloidal particles and their "image dipoles" that appear within planar substrate. Since the particles interact with their own images, this system enables massively parallel surface force measurements (>100 measurements) in a single experiment, and allows statistical properties of particle-surface adhesion energies to be extracted as a function of loading rate. With this approach, I was able to probe sub-picoNewton surface interactions between colloidal particles and several substrates at the lowest force loading rates ever achieved. In the later stages of my doctoral studies, I focused on studying patterns formed from particle-particle interaction, which serve as an experimental model of

  11. The formation of synapses in amphibian striated muscle during development.

    Science.gov (United States)

    Bennett, M R; Pettigrew, A G

    1975-10-01

    1. A study has been made of the formation of synapses in developing reinnervated and cross-reinnervated amphibian twitch muscles which receive either a focal (iliofibularis) or a distributed (sartorius) innervation from 'en plaque' nerve terminals using histological, ultrastructural and electrophysiological techniques. 2. During the development of the tadpole through metamorphosis to the adult frog, the sartorius myofibres increased in length at about twice the rate of the iliofibularis myofibres, due to a fast rate of growth at their insertions on to the pelvic tendon. 3. The short iliofibularis and sartorius myofibres of young tadpoles (800 mum long) possessed only a single synapse and the iliofibularis myofibres did not receive any further innervation during development. However the sartorius myofibres received further transient innervation on the new muscle laid down during development at the fast growing pelvic insertion, until the distance between the original synapse formed on the myofibres and the synapse at the pelvic end of the muscle was about 12 mm. 4. During development synapses possessed either skewed, multimodal, or unimodal m.e.p.p. amplitude-frequency distributions; the intervals between m.e.p.p.s. were not distributed randomly according to a Poisson process, as m.e.p.p.s. of similar amplitudes tended to be separated by very short intervals; the unit-size e.p.p. had a similar amplitude-frequency distribution as the m.e.p.p.s. if these had a unimodal distribution. 5. Reinnervation or cross-reinnervation of the sartorius and the iliofibularis muscles in adults or at a late stage of development simply reconstituted the normal focal and distributed innervation patterns of the muscles, as found in the control muscles of the contralateral and unoperated legs. 6. These observations on synapse formation in amphibia are consistent with the hypothesis that during development the axon making the initial synaptic contact on the muscle cells induces a property

  12. Pattern Formation and Complexity Emergence

    Science.gov (United States)

    Berezin, Alexander A.

    2001-03-01

    Success of nonlinear modelling of pattern formation and self-organization encourages speculations on informational and number theoretical foundations of complexity emergence. Pythagorean "unreasonable effectiveness of integers" in natural processes is perhaps extrapolatable even to universal emergence "out-of-nothing" (Leibniz, Wheeler). Because rational numbers (R = M/N) are everywhere dense on real axis, any digital string (hence any "book" from "Library of Babel" of J.L.Borges) is "recorded" infinitely many times in arbitrary many rationals. Furthermore, within any arbitrary small interval there are infinitely many Rs for which (either or both) integers (Ms and Ns) "carry" any given string of any given length. Because any iterational process (such as generation of fractal features of Mandelbrot Set) is arbitrary closely approximatable with rational numbers, the infinite pattern of integers expresses itself in generation of complexity of the world, as well as in emergence of the world itself. This "tunnelling" from Platonic World ("Platonia" of J.Barbour) to a real (physical) world is modern recast of Leibniz's motto ("for deriving all from nothing there suffices a single principle").

  13. Soleus muscle injury: sensitivity of ultrasound patterns

    Energy Technology Data Exchange (ETDEWEB)

    Balius, Ramon [Sport Catalan Council, Generalitat de Catalunya, Barcelona (Spain); Clinica CMI Diagonal, Barcelona (Spain); Rodas, Gil [F.C. Barcelona Medical Services, Barcelona (Spain); Pedret, Carles [Clinica CMI Diagonal, Barcelona (Spain); Clinica Mapfre de Medicina del Tenis, Sports Medicine and Imaging Department, Barcelona (Spain); Centre de Diagnostic per Imatge de Tarragona, Tarragona (Spain); Capdevila, Lluis [Universitat Autonoma de Barcelona, Laboratory of Sport Psychology, Barcelona (Spain); Alomar, Xavier [Clinica Creu Blanca, Barcelona (Spain); Bong, David A. [Instituto Poal de Reumatologia, Barcelona (Spain)

    2014-06-15

    To assess the sensitivity of ultrasound in detecting soleus muscle lesions diagnosed on magnetic resonance imaging (MRI) and to characterize their location, ultrasound pattern, and evolution. Ultrasound and MRI studies were performed between May 2009 and February 2013 on all patients who presented to the Medical Services Clinic of the Catalan Sport Council with the initial onset of sharp pain in the calf compatible with injury of the soleus muscle. An inter-observer ultrasound reliability study was also performed. A total of 55 cases of soleus injury were studied prospectively (22 with right leg involvement, 33 left) by ultrasound and MRI, which was utilized as the ''gold standard.'' In MRI studies, 24 cases (43.7 %) had myofascial injuries that were localized in the posterior aponeurosis (PMF) in 15 cases (27.3 %) and in the anterior aponeurosis (AMF) in 9 (16.4 %). Thirty-one cases (56.3 %) were musculotendinous injuries, with 9 cases (16.4 %) in the medial aponeurosis (MMT), 11 cases (20 %) in the lateral aponeurosis (LMT), and 11 cases (20 %) in the central tendon (CMT). In comparison to MRI, ultrasound was able to detect injury to the soleus in 27.2 % of cases. No injuries were detected by ultrasound alone. Posterior myofascial injuries were more likely to be detected by ultrasound than anterior myofascial injuries or all types of musculotendinous injuries. Ultrasound patterns for each type of injury were described. Ultrasound is not a sensitive technique for detecting and assessing soleus traumatic tears compared with MRI, although the sensitivity is enhanced by a thorough anatomically based ultrasound examination. Timing of the ultrasound examination may be of importance. Each type of soleus injury appears to have a characteristic ultrasound pattern based on a defect of connective expansions, the existence of small myofascial filiform collections, and the rarefaction of the fibrillar area. (orig.)

  14. Anisotropic assembly and pattern formation

    Science.gov (United States)

    von Brecht, James H.; Uminsky, David T.

    2017-01-01

    We investigate the role of anisotropy in two classes of individual-based models for self-organization, collective behavior and self-assembly. We accomplish this via first-order dynamical systems of pairwise interacting particles that incorporate anisotropic interactions. At a continuum level, these models represent the natural anisotropic variants of the well-known aggregation equation. We leverage this framework to analyze the impact of anisotropic effects upon the self-assembly of co-dimension one equilibrium structures, such as micelles and vesicles. Our analytical results reveal the regularizing effect of anisotropy, and isolate the contexts in which anisotropic effects are necessary to achieve dynamical stability of co-dimension one structures. Our results therefore place theoretical limits on when anisotropic effects can be safely neglected. We also explore whether anisotropic effects suffice to induce pattern formation in such particle systems. We conclude with brief numerical studies that highlight various aspects of the models we introduce, elucidate their phase structure and partially validate the analysis we provide.

  15. Patterning the dorsal longitudinal flight muscles (DLM) of Drosophila: insights from the ablation of larval scaffolds

    Science.gov (United States)

    Fernandes, J. J.; Keshishian, H.

    1996-01-01

    The six Dorsal Longitudinal flight Muscles (DLMs) of Drosophila develop from three larval muscles that persist into metamorphosis and serve as scaffolds for the formation of the adult fibers. We have examined the effect of muscle scaffold ablation on the development of DLMs during metamorphosis. Using markers that are specific to muscle and myoblasts we show that in response to the ablation, myoblasts which would normally fuse with the larval muscle, fuse with each other instead, to generate the adult fibers in the appropriate regions of the thorax. The development of these de novo DLMs is delayed and is reflected in the delayed expression of erect wing, a transcription factor thought to control differentiation events associated with myoblast fusion. The newly arising muscles express the appropriate adult-specific Actin isoform (88F), indicating that they have the correct muscle identity. However, there are frequent errors in the number of muscle fibers generated. Ablation of the larval scaffolds for the DLMs has revealed an underlying potential of the DLM myoblasts to initiate de novo myogenesis in a manner that resembles the mode of formation of the Dorso-Ventral Muscles, DVMs, which are the other group of indirect flight muscles. Therefore, it appears that the use of larval scaffolds is a superimposition on a commonly used mechanism of myogenesis in Drosophila. Our results show that the role of the persistent larval muscles in muscle patterning involves the partitioning of DLM myoblasts, and in doing so, they regulate formation of the correct number of DLM fibers.

  16. Patterns of age-associated degeneration differ in shoulder muscles

    Directory of Open Access Journals (Sweden)

    Yotam eRaz

    2015-12-01

    Full Text Available Shoulder complaints are common in the elderly and hamper daily functioning. These complaints are often caused by tears in the muscle-tendon units of the rotator cuff (RC. The four RC muscles stabilize the shoulder joint. While some RC muscles are frequently torn in shoulder complaints others remain intact. The pathological changes in RC muscles are poorly understood. We investigated changes in RC muscle pathology combining radiological and histological procedures. We measured cross sectional area (CSA and fatty infiltration from Magnetic Resonance Imaging with Arthrography in subjects without (N=294 and with (N=109 RC-tears. Normalized muscle CSA of the four RC muscles and the deltoid shoulder muscle were compared and age-associated patterns of muscle atrophy and fatty infiltration were constructed. We identified two distinct age-associated patterns: in the supraspinatus and subscapularis RC muscles CSAs continuously declined throughout adulthood, whereas in the infraspinatus and deltoid reduced CSA was prominent from midlife onwards. In the teres minor, CSA was unchanged with age. Most importantly, age-associated patterns were highly similar between subjects without RC tear and those with RC-tears. This suggests that extensive RC muscle atrophy during aging could contribute to RC pathology. We compared muscle pathology between torn infraspinatus and non-torn teres minor and the deltoid in two patients with a massive RC-tear. In the torn infraspinatus we found pronounced fatty droplets, an increase in extracellular collagen-1, a loss of myosin heavy chain-1 expression in myofibers and an increase in Pax7-positive cells. However, the adjacent intact teres minor and deltoid exhibited healthy muscle features. This suggests that satellite cells and the extracellular matrix may contribute to extensive muscle fibrosis in torn RC. We suggest that torn RC muscles display hallmarks of muscle aging whereas the teres minor could represent an aging

  17. Patterns of Age-Associated Degeneration Differ in Shoulder Muscles

    Science.gov (United States)

    Raz, Yotam; Henseler, Jan F.; Kolk, Arjen; Riaz, Muhammad; van der Zwaal, Peer; Nagels, Jochem; Nelissen, Rob G. H. H.; Raz, Vered

    2015-01-01

    Shoulder complaints are common in the elderly and hamper daily functioning. These complaints are often caused by tears in the muscle-tendon units of the rotator cuff (RC). The four RC muscles stabilize the shoulder joint. While some RC muscles are frequently torn in shoulder complaints others remain intact. The pathological changes in RC muscles are poorly understood. We investigated changes in RC muscle pathology combining radiological and histological procedures. We measured cross sectional area (CSA) and fatty infiltration from Magnetic Resonance Imaging with Arthrography (MRA) in subjects without (N = 294) and with (N = 109) RC-tears. Normalized muscle CSA of the four RC muscles and the deltoid shoulder muscle were compared and age-associated patterns of muscle atrophy and fatty infiltration were constructed. We identified two distinct age-associated patterns: in the supraspinatus and subscapularis RC muscles CSAs continuously declined throughout adulthood, whereas in the infraspinatus and deltoid reduced CSA was prominent from midlife onwards. In the teres minor, CSA was unchanged with age. Most importantly, age-associated patterns were highly similar between subjects without RC tear and those with RC-tears. This suggests that extensive RC muscle atrophy during aging could contribute to RC pathology. We compared muscle pathology between torn infraspinatus and non-torn teres minor and the deltoid in two patients with a massive RC-tear. In the torn infraspinatus we found pronounced fatty droplets, an increase in extracellular collagen-1, a loss of myosin heavy chain-1 expression in myofibers and an increase in Pax7-positive cells. However, the adjacent intact teres minor and deltoid exhibited healthy muscle features. This suggests that satellite cells and the extracellular matrix may contribute to extensive muscle fibrosis in torn RC. We suggest that torn RC muscles display hallmarks of muscle aging whereas the teres minor could represent an aging

  18. Patterns of Age-Associated Degeneration Differ in Shoulder Muscles.

    Science.gov (United States)

    Raz, Yotam; Henseler, Jan F; Kolk, Arjen; Riaz, Muhammad; van der Zwaal, Peer; Nagels, Jochem; Nelissen, Rob G H H; Raz, Vered

    2015-01-01

    Shoulder complaints are common in the elderly and hamper daily functioning. These complaints are often caused by tears in the muscle-tendon units of the rotator cuff (RC). The four RC muscles stabilize the shoulder joint. While some RC muscles are frequently torn in shoulder complaints others remain intact. The pathological changes in RC muscles are poorly understood. We investigated changes in RC muscle pathology combining radiological and histological procedures. We measured cross sectional area (CSA) and fatty infiltration from Magnetic Resonance Imaging with Arthrography (MRA) in subjects without (N = 294) and with (N = 109) RC-tears. Normalized muscle CSA of the four RC muscles and the deltoid shoulder muscle were compared and age-associated patterns of muscle atrophy and fatty infiltration were constructed. We identified two distinct age-associated patterns: in the supraspinatus and subscapularis RC muscles CSAs continuously declined throughout adulthood, whereas in the infraspinatus and deltoid reduced CSA was prominent from midlife onwards. In the teres minor, CSA was unchanged with age. Most importantly, age-associated patterns were highly similar between subjects without RC tear and those with RC-tears. This suggests that extensive RC muscle atrophy during aging could contribute to RC pathology. We compared muscle pathology between torn infraspinatus and non-torn teres minor and the deltoid in two patients with a massive RC-tear. In the torn infraspinatus we found pronounced fatty droplets, an increase in extracellular collagen-1, a loss of myosin heavy chain-1 expression in myofibers and an increase in Pax7-positive cells. However, the adjacent intact teres minor and deltoid exhibited healthy muscle features. This suggests that satellite cells and the extracellular matrix may contribute to extensive muscle fibrosis in torn RC. We suggest that torn RC muscles display hallmarks of muscle aging whereas the teres minor could represent an aging

  19. Separation vortices and pattern formation

    DEFF Research Database (Denmark)

    Andersen, Anders Peter; Bohr, Tomas; Schnipper, Teis

    2010-01-01

    In this paper examples are given of the importance of flow separation for fluid patterns at moderate Reynolds numbers—both in the stationary and in the time-dependent domain. In the case of circular hydraulic jumps, it has been shown recently that it is possible to generalise the Prandtl–Kármán–P...... results for the vortex patterns behind a flapping foil in a flowing soap film, which shows the interaction and competition between the vortices shed from the round leading edge (like the von Kármán vortex street) and those created at the sharp trailing edge.......-time evolution of the sand ripple pattern, which has the surprising features that it breaks the local sand conservation and has long-range interaction, features that can be underpinned by experiments. Very similar vortex dynamics takes place around oscillating structures such as wings and fins. Here, we present...

  20. Separation vortices and pattern formation

    DEFF Research Database (Denmark)

    Andersen, Anders Peter; Bohr, Tomas; Schnipper, Teis

    2010-01-01

    In this paper examples are given of the importance of flow separation for fluid patterns at moderate Reynolds numbers—both in the stationary and in the time-dependent domain. In the case of circular hydraulic jumps, it has been shown recently that it is possible to generalise the Prandtl–Kármán–P...... results for the vortex patterns behind a flapping foil in a flowing soap film, which shows the interaction and competition between the vortices shed from the round leading edge (like the von Kármán vortex street) and those created at the sharp trailing edge....

  1. Pattern formation in rotating fluids

    Science.gov (United States)

    Bühler, Karl

    2009-06-01

    Flows in nature and technology are often associated with specific structures and pattern. This paper deals with the development and behaviour of such flow pattern. Flow structures are important for the mass, momentum and energy transport. The behaviour of different flow pattern is used by engineers to obtain an efficient mass and energy consumption. Mechanical power is transmitted via the momentum of rotating machine parts. Therefore the physical and mathematical knowledge of these basic concepts is important. Theoretical and experimental investigations of principle experiments are described in the following. We start with the classical problem of the flow between two concentric cylinders where the inner cylinder rotates. Periodic instabilities occur which are called Taylor vortices. The analogy between the cylindrical gap flow, the heat transfer in a horizontal fluid layer exposed to the gravity field and the boundary layer flow along concave boundaries concerning their stability behaviour is addressed. The vortex breakdown phenomenon in a cylinder with rotating cover is also described. A generalization to spherical sectors leads then to investigations with different boundary conditions. The spherical gap flow exhibits interesting phenomena concerning the nonlinear character of the Navier-Stokes equations. Multiple solutions in the nonlinear regime give rise to different routes during the laminar-turbulent transition. The interaction of two rotating spheres results in flow structures with separation and stagnation lines. Experimental results are confirmed by numerical simulations.

  2. Muscle activation patterns in posttraumatic neck pain

    NARCIS (Netherlands)

    Nederhand, Marcus Johannes

    2003-01-01

    As an important consequence of our research, we question the relevance of the criteria of the WAD injury severity classification system. We showed that the musculoskeletal signs in WAD grade II are not characterized by muscle spasm, (i.e. increase of muscle activity), but rather by a decrease in mus

  3. Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

    Science.gov (United States)

    Bar-On, Lynn; Aertbeliën, Erwin; Molenaers, Guy; Desloovere, Kaat

    2014-01-01

    The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP) these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV) of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG) from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG) compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (pmuscles into activation patterns (pmuscles with different patterns react differently to treatment.

  4. Pattern formation with trapped ions

    CERN Document Server

    Lee, Tony E

    2010-01-01

    We propose an experiment to study collective behavior in a nonlinear medium of trapped ions. Using laser cooling and heating and an anharmonic trap potential, one can turn an ion into a nonlinear van der Pol-Duffing oscillator. A chain of ions interacting electrostatically has stable plane waves for all parameters. The system also behaves like an excitable medium, since a sufficiently large perturbation generates a travelling pulse. Small chains exhibit multistability and limit cycles. We account for noise from spontaneous emission in the amplitude equation and find that the patterns are observable for realistic experimental parameters. The tunability of ion traps makes them an exciting setting to study nonequilibrium statistical physics.

  5. Cellular Automaton Modeling of Pattern Formation

    NARCIS (Netherlands)

    Boerlijst, M.C.

    2006-01-01

    Book review Andreas Deutsch and Sabine Dormann, Cellular Automaton Modeling of Biological Pattern Formation, Characterization, Applications, and Analysis, Birkhäuser (2005) ISBN 0-8176-4281-1 331pp..

  6. Muscle activity pattern dependent pain development and alleviation

    DEFF Research Database (Denmark)

    Sjøgaard, Gisela; Søgaard, Karen

    2014-01-01

    during physical activities at leisure and sport the motor recruitment patterns are more dynamic including regularly relatively high muscle forces - also activating type 2 muscles fibers - as well as periods of full relaxation even of the type 1 muscle fibers. Such activity is unrelated to muscle pain......Muscle activity is for decades considered to provide health benefits irrespectively of the muscle activity pattern performed and whether it is during e.g. sports, transportation, or occupational work tasks. Accordingly, the international recommendations for public health-promoting physical activity...... do not distinguish between occupational and leisure time physical activity. However, in this body of literature, attention has not been paid to the extensive documentation on occupational physical activity imposing a risk of impairment of health - in particular musculoskeletal health in terms...

  7. Dimensionality of joint torques and muscle patterns for reaching

    Directory of Open Access Journals (Sweden)

    Marta eRusso

    2014-03-01

    Full Text Available Muscle activities underlying many motor behaviors can be generated by a small number of basic activation patterns with specific features shared across movement conditions. Such low-dimensionality suggests that the central nervous system (CNS relies on a modular organization to simplify control. However, the relationship between the dimensionality of muscle patterns and that of joint torques is not fixed, because of redundancy and non-linearity in mapping the former into the latter, and needs to be investigated. We compared the torques acting at four arm joints during fast reaching movements in different directions in the frontal and sagittal planes and the underlying muscle patterns. The dimensionality of the non-gravitational components of torques and muscle patterns in the spatial, temporal, and spatiotemporal domains was estimated by multidimensional decomposition techniques. The spatial organization of torques was captured by two or three generators, indicating that not all the available coordination patterns are employed by the CNS. A single temporal generator with a biphasic profile was identified, generalizing previous observations on a single plane. The number of spatiotemporal generators was equal to the product of the spatial and temporal dimensionalities and their organization was essentially synchronous. Muscle pattern dimensionalities were higher than torques dimensionalities but also higher than the minimum imposed by the inherent non-negativity of muscle activations. The spatiotemporal dimensionality of the muscle patterns was lower than the product of their spatial and temporal dimensionality, indicating the existence of specific asynchronous coordination patterns. Thus, the larger dimensionalities of the muscle patterns may be required for CNS to overcome the non-linearities of the musculoskeletal system and to flexibly generate endpoint trajectories with simple kinematic features using a limited number of building blocks.

  8. Pattern Formation in Driven Systems

    Science.gov (United States)

    Klymko, Katherine

    Model colloidal particles of two types, driven in opposite directions, will in two dimensions segregate into lanes, a phenomenon studied extensively by Lowen and co-workers [Dzubiella et al. Phys. Rev. E 65, 021402 (2002)]. We have simulated mixtures of oppositely-driven particles using three numerical protocols. We find that laning results from enhanced diffusion, in the direction perpendicular to the drive, of particles surrounded by particles of the opposite type, consistent with the observation of Vissers et al. [Soft Matter 7, 6, 2352 (2011)]. By comparing protocols we find that enhanced diffusion follows from a simple geometrical constraint: oppositely-driven particles must, in the time taken to encounter each other in the direction of the drive, diffuse in the perpendicular direction by about one particle diameter. This constraint implies that the effective lateral diffusion constant grows linearly with drive speed and as the square root of the packing fraction, a prediction supported by our numerics. By invoking an analogy between hard particles with environment-dependent mobilities and mutually attractive particles we argue that there exists an equilibrium system whose pattern-forming properties are similar to those of the driven system. Katherine Klymko acknowledges support from the NSF Graduate Research Fellowship.

  9. Blood drop patterns: Formation and applications.

    Science.gov (United States)

    Chen, Ruoyang; Zhang, Liyuan; Zang, Duyang; Shen, Wei

    2016-05-01

    The drying of a drop of blood or plasma on a solid substrate leads to the formation of interesting and complex patterns. Inter- and intra-cellular and macromolecular interactions in the drying plasma or blood drop are responsible for the final morphologies of the dried patterns. Changes in these cellular and macromolecular components in blood caused by diseases have been suspected to cause changes in the dried drop patterns of plasma and whole blood, which could be used as simple diagnostic tools to identify the health of humans and livestock. However, complex physicochemical driving forces involved in the pattern formation are not fully understood. This review focuses on the scientific development in microscopic observations and pattern interpretation of dried plasma and whole blood samples, as well as the diagnostic applications of pattern analysis. Dried drop patterns of plasma consist of intricate visible cracks in the outer region and fine structures in the central region, which are mainly influenced by the presence and concentration of inorganic salts and proteins during drying. The shrinkage of macromolecular gel and its adhesion to the substrate surface have been thought to be responsible for the formation of the cracks. Dried drop patterns of whole blood have three characteristic zones; their formation as functions of drying time has been reported in the literature. Some research works have applied engineering treatment to the evaporation process of whole blood samples. The sensitivities of the resultant patterns to the relative humidity of the environment, the wettability of the substrates, and the size of the drop have been reported. These research works shed light on the mechanisms of spreading, evaporation, gelation, and crack formation of the blood drops on solid substrates, as well as on the potential applications of dried drop patterns of plasma and whole blood in diagnosis.

  10. Patterns of experimentally induced pain in pericranial muscles

    DEFF Research Database (Denmark)

    Schmidt-Hansen, Peter Thede; Svensson, Peter; Jensen, Troels Staehelin

    2006-01-01

    Nociceptive mechanisms in the craniofacial muscle tissue are poorly understood. The pain pattern in individual pericranial muscles has not been described before. Experimental muscle pain was induced by standardized infusions of 0.2 ml 1 m hypertonic saline into six craniofacial muscles (masseter....... cervically innervated dermatomes (P pain patterns and pain sensitivity in different craniofacial muscles in healthy volunteers, which may be of importance for further research on different craniofacial pain conditions......., anterior temporalis, posterior temporalis, trapezius, splenius capitis and sternocleidomastoid) in 20 healthy subjects. The pressure pain thresholds (PPTs) were determined before and after infusions. The subjects continuously reported intensity of saline-induced pain on an electronic visual analogue scale...

  11. Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

    Directory of Open Access Journals (Sweden)

    Lynn Bar-On

    Full Text Available The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01. The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between

  12. Emergent pattern formation in an interstitial biofilm

    CERN Document Server

    Zachreson, Cameron; Whitchurch, Cynthia; Toth, Milos

    2016-01-01

    Collective behavior of bacterial colonies plays critical roles in adaptability, survivability, biofilm expansion and infection. We employ an individual-based model of an interstitial biofilm to study emergent pattern formation based on the assumptions that rod-shaped bacteria furrow through a viscous environment, and excrete extracellular polymeric substances which bias their rate of motion. Because the bacteria furrow through their environment, the substratum stiffness is a key control parameter behind the formation of distinct morphological patterns. By systematically varying this property (which we quantify with a stiffness coefficient {\\gamma}), we show that subtle changes in the substratum stiffness can give rise to a stable state characterized by a high degree of local order and long-range pattern formation. The ordered state exhibits characteristics typically associated with bacterial fitness advantages, even though it is induced by changes in environmental conditions rather than changes in biological ...

  13. Muscle synergy patterns as physiological markers of motor cortical damage.

    Science.gov (United States)

    Cheung, Vincent C K; Turolla, Andrea; Agostini, Michela; Silvoni, Stefano; Bennis, Caoimhe; Kasi, Patrick; Paganoni, Sabrina; Bonato, Paolo; Bizzi, Emilio

    2012-09-04

    The experimental findings herein reported are aimed at gaining a perspective on the complex neural events that follow lesions of the motor cortical areas. Cortical damage, whether by trauma or stroke, interferes with the flow of descending signals to the modular interneuronal structures of the spinal cord. These spinal modules subserve normal motor behaviors by activating groups of muscles as individual units (muscle synergies). Damage to the motor cortical areas disrupts the orchestration of the modules, resulting in abnormal movements. To gain insights into this complex process, we recorded myoelectric signals from multiple upper-limb muscles in subjects with cortical lesions. We used a factorization algorithm to identify the muscle synergies. Our factorization analysis revealed, in a quantitative way, three distinct patterns of muscle coordination-including preservation, merging, and fractionation of muscle synergies-that reflect the multiple neural responses that occur after cortical damage. These patterns varied as a function of both the severity of functional impairment and the temporal distance from stroke onset. We think these muscle-synergy patterns can be used as physiological markers of the status of any patient with stroke or trauma, thereby guiding the development of different rehabilitation approaches, as well as future physiological experiments for a further understanding of postinjury mechanisms of motor control and recovery.

  14. Pattern formation in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Parsek, Matthew R.; Tolker-Nielsen, Tim

    2008-01-01

    Bacteria are capable of forming elaborate multicellular communities called biofilms. Pattern formation in biofilms depends on cell proliferation and cellular migration in response to the available nutrients and other external cues, as well as on self-generated intercellular signal molecules...... and the production of an extracellular matrix that serves as a structural 'scaffolding' for the biofilm cells. Pattern formation in biofilms allows cells to position themselves favorably within nutrient gradients and enables buildup and maintenance of physiologically distinct subpopulations, which facilitates...... survival of one or more subpopulations upon environmental insult, and therefore plays an important role in the innate tolerance displayed by biofilms toward adverse conditions....

  15. Transverse optical and atomic pattern formation

    CERN Document Server

    Schmittberger, Bonnie L

    2016-01-01

    The study of transverse optical pattern formation has been studied extensively in nonlinear optics, with a recent experimental interest in studying the phenomenon using cold atoms, which can undergo real-space self-organization. Here, we describe our experimental observation of pattern formation in cold atoms, which occurs using less than 1 microWatt of applied power. We show that the optical patterns and the self-organized atomic structures undergo continuous symmetry-breaking, which is characteristic of non-equilibrium phenomena in a multimode system. To theoretically describe pattern formation in cold atoms, we present a self-consistent model that allows for tight atomic bunching in the applied optical lattice. We derive the nonlinear refractive index of a gas of multi-level atoms in an optical lattice, and we derive the threshold conditions under which pattern formation occurs. We show that, by using small detunings and sub-Doppler temperatures, one achieves two orders of magnitude reduced intensity thres...

  16. Pattern Formation in a Bacterial Colony Model

    Directory of Open Access Journals (Sweden)

    Xinze Lian

    2014-01-01

    Full Text Available We investigate the spatiotemporal dynamics of a bacterial colony model. Based on the stability analysis, we derive the conditions for Hopf and Turing bifurcations. Furthermore, we present novel numerical evidence of time evolution of patterns controlled by parameters in the model and find that the model dynamics exhibit a diffusion controlled formation growth to spots, holes and stripes pattern replication, which show that the bacterial colony model is useful in revealing the spatial predation dynamics in the real world.

  17. Chaotic Turing pattern formation in spatiotemporal systems

    Institute of Scientific and Technical Information of China (English)

    XIAO Jing-hua; LI Hai-hong; YANG Jun-zhong; HU Gang

    2006-01-01

    The problem of Turing pattern formation has attracted much attention in nonlinear science as well as physics,chemistry and biology.So far spatially ordered Turing patterns have been observed in stationary and oscillatory media only.In this paper we find that spatially ordered Turing patterns exist in chaotic extended systems.And chaotic Turing patterns are strikingly rich and surprisingly beautiful with their space structures.These findings are in sharp contrast with the intuition of pseudo-randomness of chaos.The richness and beauty of the chaotic Turing patterns are attributed to a large variety of symmetry properties realized by various types of self-organizations of partial chaos synchronizations.

  18. Fractals in Spatial Patterns of Vegetation Formations

    Institute of Scientific and Technical Information of China (English)

    SONG Zhiyuan; HUANG Daming; Masae Shiyomi; WANG Yusheng; Shigeo Takahashi; Hori Yoshimichi; Yasuo Yamamuru; CHEN Jun

    2006-01-01

    The spatial distribution patterns of species are always scale-dependent and spatially self-similar in ecological systems. In this work, vegetation distribution data collected from the vegetation map of the Xigazê region was analyzed using a box-counting method. The power law of the box-counting dimension (DB) across a range of scales (5-160 km) confirms the fractal patterns for most vegetation formations, while the fluctuations of the scale-specific DB among the different abundance groups indicate limitations of fractal coherence. The fractal method is shown to be a useful tool for measuring the distribution patterns of vegetation formations across scales, which provides important information for both species and habitat conservation, especially in landscape management.

  19. The growth patterns of three hindlimb muscles in the chicken.

    Science.gov (United States)

    Helmi, C; Cracraft, J

    1977-07-01

    This study was designed to investigate the growth patterns of three hindlimb muscles of the chicken relative to the functional-biomechanical demands of increasing body size. The biceps femoris, a bipennate non-postural muscle, grew relatively faster in terms of wet and dry weight than did the parallel-fibred adductor superficialis or the unipennate adductor profundus, both postural muscles. All three muscles exhibited positive allometry (relative to body weight) in muscle length but only biceps femoris and adductor profundus showed positive allometry in cross sectional area adductor superficialis having isometric growth in this parameter. In biceps femoris and adductor superficialis the lengths of the longest and shortest fasciculi grew at equal rates, whereas in adductor profundus the shortest fasciculi grew faster than the longest. We conclude that muscle weight alone is an insufficient indicator of changing function in growing muscle. Hence, growth studies should include other functionally relevant parameters such as cross sectional area, which is proportional to the force-producing capabilities of the muscle, or fibre (fasciculus) length, which is indicative of the absolute amount of stretching or shortening that is possible and of the contraction velocity.

  20. Pattern formation during C. elegans vulval induction.

    Science.gov (United States)

    Wang, M; Sternberg, P W

    2001-01-01

    Studies of C. elegans vulval development provide insights into the process of pattern formation during animal development. The invariant pattern of vulval precursor cell fates is specified by the integration of at least two signaling systems. Recent findings suggest that multiple, partially redundant mechanisms are involved in patterning the vulval precursor cells. The inductive signal activates the LET-60/RAS signaling pathway and induces the 1 degree fate, whereas the lateral signal mediated by LIN-12/Notch is required for specification of the 2 degrees fate. Several regulatory pathways antagonize the RAS signaling pathway and specify the non-vulval 3 degrees fate in the absence of induction. The temporal and spatial regulation of VPC competence and production of the inductive and the lateral signal are precisely coordinated to ensure the wild-type vulval pattern.

  1. Pattern formation in superdiffusion Oregonator model

    Science.gov (United States)

    Feng, Fan; Yan, Jia; Liu, Fu-Cheng; He, Ya-Feng

    2016-10-01

    Pattern formations in an Oregonator model with superdiffusion are studied in two-dimensional (2D) numerical simulations. Stability analyses are performed by applying Fourier and Laplace transforms to the space fractional reaction-diffusion systems. Antispiral, stable turing patterns, and travelling patterns are observed by changing the diffusion index of the activator. Analyses of Floquet multipliers show that the limit cycle solution loses stability at the wave number of the primitive vector of the travelling hexagonal pattern. We also observed a transition between antispiral and spiral by changing the diffusion index of the inhibitor. Project supported by the National Natural Science Foundation of China (Grant Nos. 11205044 and 11405042), the Research Foundation of Education Bureau of Hebei Province, China (Grant Nos. Y2012009 and ZD2015025), the Program for Young Principal Investigators of Hebei Province, China, and the Midwest Universities Comprehensive Strength Promotion Project.

  2. Pattern formation and functionality in swarm models

    CERN Document Server

    Rauch, E M; Chialvo, D R; Rauch, Erik M; Millonas, Mark M; Chialvo, Dante R

    1995-01-01

    We explore a simplified class of models we call swarms, which are inspired by the collective behavior of social insects. We perform a mean-field stability analysis and perform numerical simulations of the model. Several interesting types of behavior emerge in the vicinity of a second-order phase transition in the model, including the formation of stable lines of traffic flow, and memory reconstitution and bootstrapping. In addition to providing an understanding of certain classes of biological behavior, these models bear a generic resemblance to a number of pattern formation processes in the physical sciences.

  3. Changes in muscle recruitment patterns during skill acquisition.

    Science.gov (United States)

    Carson, R G; Riek, S

    2001-05-01

    The control of movement is predicated upon a system of constraints of musculoskeletal and neural origin. The focus of the present study was upon the manner in which such constraints are adapted or superseded during the acquisition of motor skill. Individuals participated in five experimental sessions, in which they attempted to produce abduction-adduction movements of the index finger in time with an auditory metronome. During each trial, the metronome frequency was increased in eight steps from an individually determined base frequency. Electromyographic (EMG) activity was recorded from first dorsal interosseous (FDI), first volar interosseous (FVI), flexor digitorum superficialis (FDS), and extensor digitorum communis (EDC) muscles. The movements produced on the final day of acquisition more accurately matched the required profile, and exhibited greater spatial and temporal stability, than those generated during initial performance. In the early stages of skill acquisition, an alternating pattern of activation in FDI and FVI was maintained, even at the highest frequencies. In contrast, as the frequency of movement was increased, activity in FDS and EDC was either tonic or intermittent. As learning proceeded, alterations in recruitment patterns were expressed primarily in the extrinsic muscles (EDC and FDS). These changes took the form of increases in the postural role of these muscles, shifts to phasic patterns of activation, or selective disengagement of these muscles. These findings suggest that there is considerable flexibility in the composition of muscle synergies, which is exploited by individuals during the acquisition of coordination.

  4. Emergent pattern formation in an interstitial biofilm

    Science.gov (United States)

    Zachreson, Cameron; Wolff, Christian; Whitchurch, Cynthia B.; Toth, Milos

    2017-01-01

    Collective behavior of bacterial colonies plays critical roles in adaptability, survivability, biofilm expansion and infection. We employ an individual-based model of an interstitial biofilm to study emergent pattern formation based on the assumptions that rod-shaped bacteria furrow through a viscous environment and excrete extracellular polymeric substances which bias their rate of motion. Because the bacteria furrow through their environment, the substratum stiffness is a key control parameter behind the formation of distinct morphological patterns. By systematically varying this property (which we quantify with a stiffness coefficient γ ), we show that subtle changes in the substratum stiffness can give rise to a stable state characterized by a high degree of local order and long-range pattern formation. The ordered state exhibits characteristics typically associated with bacterial fitness advantages, even though it is induced by changes in environmental conditions rather than changes in biological parameters. Our findings are applicable to a broad range of biofilms and provide insights into the relationship between bacterial movement and their environment, and basic mechanisms behind self-organization of biophysical systems.

  5. "Electromyographic pattern of masticatory muscles in altered dentition" Part II

    Directory of Open Access Journals (Sweden)

    H D Adhikari

    2011-01-01

    Full Text Available Aim : The aim of this study is to show that a change in occlusal contacting pattern of tooth has definite influence over the behavior of orofacial musculature, resulting deleterious effect on it. Keeping this in view, the electromyographic (EMG activity of temporalis and masseter muscles in rest position of mandible, maximum clenching and chewing, was studied in total 24 subjects--14 subjects with normal occlusion and rest 10 with normal occlusion and one tooth carious which was prepared to receive an inlay with high point. This high point or occlusal interference was introduced intentionally to have a change in occlusion or "altered dentition". The subjects were all male medical volunteers with average age group of 20 years. A particular variety of chewing substance - chewing gum was used in this study. No EMG activity was detected in the rest position of mandible. In maximum clenching, balanced type of activity was seen bilaterally in normal occlusion.Whereas in changed occlusion, an unbalanced type of muscle activity was seen in temporalis muscle during maximum clenching. There was an overall decrease in activity in both the muscles during maximum clenching and during chewing. This decrease in activity was statistically significant in most of the times. A non-specific pattern of muscle activity resembling spasm in skeletal muscle -- a state of "hyperactivity" was also found during chewing in presence of occlusal interference. This spasm-like activity may cause pain in the muscles of masticatory apparatus. All these abnormal types of behavior of muscle were abolished after removal of high point and establishing the previous normal occlusion. It is therefore, for the clinicians to understand the importance of establishing occlusal equilibrium in day to day practice.

  6. Are muscle activation patterns altered during shod and barefoot running with a forefoot footfall pattern?

    Science.gov (United States)

    Ervilha, Ulysses Fernandes; Mochizuki, Luis; Figueira, Aylton; Hamill, Joseph

    2016-09-14

    This study aimed to investigate the activation of lower limb muscles during barefoot and shod running with forefoot or rearfoot footfall patterns. Nine habitually shod runners were asked to run straight for 20 m at self-selected speed. Ground reaction forces and thigh and shank muscle surface electromyographic (EMG) were recorded. EMG outcomes (EMG intensity [iEMG], latency between muscle activation and ground reaction force, latency between muscle pairs and co-activation index between muscle pairs) were compared across condition (shod and barefoot), running cycle epochs (pre-strike, strike, propulsion) and footfall (rearfoot and forefoot) by ANOVA. Condition affected iEMG at pre-strike epoch. Forefoot and rearfoot strike patterns induced different EMG activation time patterns affecting co-activation index for pairs of thigh and shank muscles. All these timing changes suggest that wearing shoes or not is less important for muscle activation than the way runners strike the foot on the ground. In conclusion, the guidance for changing external forces applied on lower limbs should be pointed to the question of rearfoot or forefoot footfall patterns.

  7. Pattern Formation on Networks: from Localised Activity to Turing Patterns

    Science.gov (United States)

    McCullen, Nick; Wagenknecht, Thomas

    2016-06-01

    Networks of interactions between competing species are used to model many complex systems, such as in genetics, evolutionary biology or sociology and knowledge of the patterns of activity they can exhibit is important for understanding their behaviour. The emergence of patterns on complex networks with reaction-diffusion dynamics is studied here, where node dynamics interact via diffusion via the network edges. Through the application of a generalisation of dynamical systems analysis this work reveals a fundamental connection between small-scale modes of activity on networks and localised pattern formation seen throughout science, such as solitons, breathers and localised buckling. The connection between solutions with a single and small numbers of activated nodes and the fully developed system-scale patterns are investigated computationally using numerical continuation methods. These techniques are also used to help reveal a much larger portion of of the full number of solutions that exist in the system at different parameter values. The importance of network structure is also highlighted, with a key role being played by nodes with a certain so-called optimal degree, on which the interaction between the reaction kinetics and the network structure organise the behaviour of the system.

  8. Geometry-induced protein pattern formation.

    Science.gov (United States)

    Thalmeier, Dominik; Halatek, Jacob; Frey, Erwin

    2016-01-19

    Protein patterns are known to adapt to cell shape and serve as spatial templates that choreograph downstream processes like cell polarity or cell division. However, how can pattern-forming proteins sense and respond to the geometry of a cell, and what mechanistic principles underlie pattern formation? Current models invoke mechanisms based on dynamic instabilities arising from nonlinear interactions between proteins but neglect the influence of the spatial geometry itself. Here, we show that patterns can emerge as a direct result of adaptation to cell geometry, in the absence of dynamical instability. We present a generic reaction module that allows protein densities robustly to adapt to the symmetry of the spatial geometry. The key component is an NTPase protein that cycles between nucleotide-dependent membrane-bound and cytosolic states. For elongated cells, we find that the protein dynamics generically leads to a bipolar pattern, which vanishes as the geometry becomes spherically symmetrical. We show that such a reaction module facilitates universal adaptation to cell geometry by sensing the local ratio of membrane area to cytosolic volume. This sensing mechanism is controlled by the membrane affinities of the different states. We apply the theory to explain AtMinD bipolar patterns in [Formula: see text] EcMinDE Escherichia coli. Due to its generic nature, the mechanism could also serve as a hitherto-unrecognized spatial template in many other bacterial systems. Moreover, the robustness of the mechanism enables self-organized optimization of protein patterns by evolutionary processes. Finally, the proposed module can be used to establish geometry-sensitive protein gradients in synthetic biological systems.

  9. Muscle activation patterns in patients with recurrent shoulder instability

    Science.gov (United States)

    Jaggi, Anju; Noorani, Ali; Malone, Alex; Cowan, Joseph; Lambert, Simon; Bayley, Ian

    2012-01-01

    Purpose: The aim of this study is to present muscle patterns observed with the direction of instability in a series of patients presenting with recurrent shoulder instability. Materials and Methods: A retrospective review was carried out on shoulder instability cases referred for fine wire dynamic electromyography (DEMG) studies at a specialist upper limb centre between 1981 and 2003. An experienced consultant clinical neurophysiologist performed dual needle insertion into four muscles (pectoralis major (PM), latissimus dorsi (LD), anterior deltoid (AD) and infraspinatus (IS)) in shoulders that were suspected to have increased or suppressed activation of muscles that could be contributing to the instability. Raw EMG signals were obtained while subjects performed simple uniplanar movements of the shoulder. The presence or absence of muscle activation was noted and compared to clinical diagnosis and direction of instability. Results: A total of 140 (26.6%) shoulders were referred for fine wire EMG, and 131 studies were completed. Of the shoulders tested, 122 shoulders (93%) were identified as having abnormal patterns and nine had normal patterns. PM was found to be more active in 60% of shoulders presenting with anterior instability. LD was found to be more active in 81% of shoulders with anterior instability and 80% with posterior instability. AD was found to be more active in 22% of shoulders with anterior instability and 18% with posterior instability. IS was found to be inappropriately inactive in only 3% of shoulders with anterior instability but in 25% with posterior instability. Clinical assessment identified 93% of cases suspected to have muscle patterning, but the specificity of the clinical assessment was only correct in 11% of cases. Conclusion: The DEMG results suggest that increased activation of LD may play a role in both anterior and posterior shoulder instability; increased activation of PM may play a role in anterior instability. PMID:23493512

  10. Pattern formation in nanoporous titania templates.

    Science.gov (United States)

    Richter, C; Wu, Z; Menon, L

    2007-02-01

    We have carried out a systematic investigation into the formation of nanoscaled patterns in titania (TiO2) templates under dc anodization of Ti in HF acid. At lower acid concentrations (around 0.5 wt% HF) either pores or tubes form at the surface of anodized titanium foil. The pores or nanotubes are separated from the bottom Ti layer by a thin barrier layer of TiO2. The critical voltage where the transition from pores to tubes occurs has been determined. It is observed that the transition voltage shift towards higher voltages as acid concentration is increased, with pore formation disappearing altogether at high acid concentrations. We have also carried out a systematic investigation into the dependence of pore and tube parameters on the applied dc anodization voltage. Our results indicate that the barrier layer thickness, pore and tube length increase as a function of applied voltage.

  11. Excitable Pattern Formation in Inhomogeneous Systems

    Science.gov (United States)

    Prabhakara, Kaumudi; Gholami, Azam; Zykov, Vladimir; Bodenschatz, Eberhard

    2015-03-01

    On starvation, the amoebae Dictyostelium discoideum signal via the chemo-attractant cyclic adenosine monophosphate (cAMP). The amoebae sense cAMP through membrane receptors and produce their own cAMP. Simultaneously they produce a basal level of Phosphodiesterase, an enzyme that degrades cAMP. Soon a pattern of rotating spiral waves or circular waves is formed at the multi-cellular level. The causal reasons for the selection of one or the other pattern are still unclear. Here we report experimental and theoretical investigations of the pattern-formation of mixtures of cells starved for different times. The excitability of the amoebae depends on the starvation time due to time dependent gene expressions. Cells starved for longer times are known to exhibit increased excitability. We report phase maps of the patterns for mixtures of different combinations of excitability. Numerical simulations of a modified Kessler-Levine model allow us to explain the experimental results and provide new insights into the dynamical behavior of the system. This work is supported by the Max Planck Society.

  12. Mechanisms of nascent fiber formation during avian skeletal muscle hypertrophy

    Science.gov (United States)

    McCormick, K. M.; Schultz, E.

    1992-01-01

    This study examined two putative mechanisms of new fiber formation in postnatal skeletal muscle, namely longitudinal fragmentation of existing fibers and de novo formation. The relative contributions of these two mechanisms to fiber formation in hypertrophying anterior latissimus dorsi (ALD) muscle were assessed by quantitative analysis of their nuclear populations. Muscle hypertrophy was induced by wing-weighting for 1 week. All nuclei formed during the weighting period were labeled by continuous infusion of 5-bromo-2'-deoxyuridine (BrdU), a thymidine analog, and embryonic-like fibers were identified using an antibody to ventricular-like embryonic (V-EMB) myosin. The number of BrdU-labeled and unlabeled nuclei in V-EMB-positive fibers were counted. Wing-weighting resulted in significant muscle enlargement and the appearance of many V-EMB+ fibers. The majority of V-EMB+ fibers were completely independent of mature fibers and had a nuclear density characteristics of developing fibers. Furthermore, nearly 100% of the nuclei in independent V-EMB+ fibers were labeled. These findings strongly suggest that most V-EMB+ fibers were nascent fibers formed de novo during the weighting period by satellite cell activation and fusion. Nascent fibers were found primarily in the space between fascicles where they formed a complex anastomosing network of fibers running at angles to one another. Although wing-weighting induced an increase in the number of branched fibers, there was no evidence that V-EMB+ fibers were formed by longitudinal fragmentation. The location of newly formed fibers in wing-weighted and regenerating ALD muscle was compared to determine whether satellite cells in the ALD muscle were unusual in that, if stimulated to divide, they would form fibers in the inter- and intrafascicular space. In contrast to wing-weighted muscle, nascent fibers were always found closely associated with necrotic fibers. These results suggest that wing-weighting is not simply another

  13. Mechanisms of nascent fiber formation during avian skeletal muscle hypertrophy

    Science.gov (United States)

    McCormick, K. M.; Schultz, E.

    1992-01-01

    This study examined two putative mechanisms of new fiber formation in postnatal skeletal muscle, namely longitudinal fragmentation of existing fibers and de novo formation. The relative contributions of these two mechanisms to fiber formation in hypertrophying anterior latissimus dorsi (ALD) muscle were assessed by quantitative analysis of their nuclear populations. Muscle hypertrophy was induced by wing-weighting for 1 week. All nuclei formed during the weighting period were labeled by continuous infusion of 5-bromo-2'-deoxyuridine (BrdU), a thymidine analog, and embryonic-like fibers were identified using an antibody to ventricular-like embryonic (V-EMB) myosin. The number of BrdU-labeled and unlabeled nuclei in V-EMB-positive fibers were counted. Wing-weighting resulted in significant muscle enlargement and the appearance of many V-EMB+ fibers. The majority of V-EMB+ fibers were completely independent of mature fibers and had a nuclear density characteristics of developing fibers. Furthermore, nearly 100% of the nuclei in independent V-EMB+ fibers were labeled. These findings strongly suggest that most V-EMB+ fibers were nascent fibers formed de novo during the weighting period by satellite cell activation and fusion. Nascent fibers were found primarily in the space between fascicles where they formed a complex anastomosing network of fibers running at angles to one another. Although wing-weighting induced an increase in the number of branched fibers, there was no evidence that V-EMB+ fibers were formed by longitudinal fragmentation. The location of newly formed fibers in wing-weighted and regenerating ALD muscle was compared to determine whether satellite cells in the ALD muscle were unusual in that, if stimulated to divide, they would form fibers in the inter- and intrafascicular space. In contrast to wing-weighted muscle, nascent fibers were always found closely associated with necrotic fibers. These results suggest that wing-weighting is not simply another

  14. Motor Circuit-Specific Burst Patterns Drive Different Muscle and Behavior Patterns

    Science.gov (United States)

    Diehl, Florian; White, Rachel S.; Stein, Wolfgang

    2013-01-01

    In the isolated CNS, different modulatory inputs can enable one motor network to generate multiple output patterns. Thus far, however, few studies have established whether different modulatory inputs also enable a defined network to drive distinct muscle and movement patterns in vivo, much as they enable these distinctions in behavioral studies. This possibility is not a foregone conclusion, because additional influences present in vivo (e.g., sensory feedback, hormonal modulation) could alter the motor patterns. Additionally, rhythmic neuronal activity can be transformed into sustained muscle contractions, particularly in systems with slow muscle dynamics, as in the crab (Cancer borealis) stomatogastric system used here. We assessed whether two different versions of the biphasic (protraction, retraction) gastric mill (chewing) rhythm, triggered in the isolated stomatogastric system by the modulatory ventral cardiac neurons (VCNs) and postoesophageal commissure (POC) neurons, drive different muscle and movement patterns. One distinction between these rhythms is that the lateral gastric (LG) protractor motor neuron generates tonic bursts during the VCN rhythm, whereas its POC-rhythm bursts are divided into fast, rhythmic burstlets. Intracellular muscle fiber recordings and tension measurements show that the LG-innervated muscles retain the distinct VCN-LG and POC-LG neuron burst structures. Moreover, endoscope video recordings in vivo, during VCN-triggered and POC-triggered chewing, show that the lateral teeth protraction movements exhibit the same, distinct protraction patterns generated by LG in the isolated nervous system. Thus, the multifunctional nature of an identified motor network in the isolated CNS can be preserved in vivo, where it drives different muscle activity and movement patterns. PMID:23864688

  15. Spatiotemporal characteristics of muscle patterns for ball catching

    Directory of Open Access Journals (Sweden)

    Mattia eD'Andola

    2013-08-01

    Full Text Available What sources of information and what control strategies the CNS uses to perform movements that require accurate sensorimotor coordination, such as catching a flying ball, is still debated. Here we analyzed the EMG waveforms recorded from 16 shoulder and elbow muscles in six subjects during catching of balls projected frontally from a distance of 6 m and arriving at two different heights and with three different flight times (550, 650, 750 ms. We found that a large fraction of the variation in the muscle patterns was captured by two time-varying muscle synergies, coordinated recruitment of groups of muscles with specific activation waveforms, modulated in amplitude and shifted in time according to the ball’s arrival height and flight duration. One synergy was recruited with a short and fixed delay from launch time. Remarkably, a second synergy was recruited at a fixed time before impact, suggesting that it is timed according to an accurate time-to-contact estimation. These results suggest that the control of interceptive movements relies on a combination of reactive and predictive processes through the intermittent recruitment of time-varying muscle synergies. Knowledge of the dynamic effect of gravity and drag on the ball may be then implicitly incorporated in a direct mapping of visual information into a small number of synergy recruitment parameters.

  16. Pattern formation, logistics, and maximum path probability

    Science.gov (United States)

    Kirkaldy, J. S.

    1985-05-01

    The concept of pattern formation, which to current researchers is a synonym for self-organization, carries the connotation of deductive logic together with the process of spontaneous inference. Defining a pattern as an equivalence relation on a set of thermodynamic objects, we establish that a large class of irreversible pattern-forming systems, evolving along idealized quasisteady paths, approaches the stable steady state as a mapping upon the formal deductive imperatives of a propositional function calculus. In the preamble the classical reversible thermodynamics of composite systems is analyzed as an externally manipulated system of space partitioning and classification based on ideal enclosures and diaphragms. The diaphragms have discrete classification capabilities which are designated in relation to conserved quantities by descriptors such as impervious, diathermal, and adiabatic. Differentiability in the continuum thermodynamic calculus is invoked as equivalent to analyticity and consistency in the underlying class or sentential calculus. The seat of inference, however, rests with the thermodynamicist. In the transition to an irreversible pattern-forming system the defined nature of the composite reservoirs remains, but a given diaphragm is replaced by a pattern-forming system which by its nature is a spontaneously evolving volume partitioner and classifier of invariants. The seat of volition or inference for the classification system is thus transferred from the experimenter or theoretician to the diaphragm, and with it the full deductive facility. The equivalence relations or partitions associated with the emerging patterns may thus be associated with theorems of the natural pattern-forming calculus. The entropy function, together with its derivatives, is the vehicle which relates the logistics of reservoirs and diaphragms to the analog logistics of the continuum. Maximum path probability or second-order differentiability of the entropy in isolation are

  17. Scaling functional patterns of skeletal and cardiac muscles: New non-linear elasticity approach

    CERN Document Server

    Kokshenev, Valery B

    2009-01-01

    Responding mechanically to environmental requests, muscles show a surprisingly large variety of functions. The studies of in vivo cycling muscles qualified skeletal muscles into four principal locomotor patterns: motor, brake, strut, and spring. While much effort of has been done in searching for muscle design patterns, no fundamental concepts underlying empirically established patterns were revealed. In this interdisciplinary study, continuum mechanics is applied to the problem of muscle structure in relation to function. The ability of a powering muscle, treated as a homogenous solid organ, tuned to efficient locomotion via the natural frequency is illuminated through the non-linear elastic muscle moduli controlled by contraction velocity. The exploration of the elastic force patterns known in solid state physics incorporated in activated skeletal and cardiac muscles via the mechanical similarity principle yields analytical rationalization for locomotor muscle patterns. Besides the explanation of the origin...

  18. Leader Election Problem Versus Pattern Formation Problem

    CERN Document Server

    Dieudonné, Yoann; Villain, Vincent

    2009-01-01

    Leader election and arbitrary pattern formation are fundammental tasks for a set of autonomous mobile robots. The former consists in distinguishing a unique robot, called the leader. The latter aims in arranging the robots in the plane to form any given pattern. The solvability of both these tasks turns out to be necessary in order to achieve more complex tasks. In this paper, we study the relationship between these two tasks in the semi-synchronous model (SSM), wherein the robots are weak in several aspects. In particular, they have no direct means of communication. They cannot remember any previous observation nor computation performed in any previous step. Such robots are said to be oblivious. The robots are also uniform and anonymous, i.e, they all have the same program using no global parameter (such that an identity) allowing to differentiate any of them. Moreover, none of them share any kind of common coordinate mechanism or common sense of direction, except that they agree on a common handedness (chir...

  19. Effects of patterned topography on biofilm formation

    Science.gov (United States)

    Vasudevan, Ravikumar

    2011-12-01

    Bacterial biofilms are a population of bacteria attached to each other and irreversibly to a surface, enclosed in a matrix of self-secreted polymers, among others polysaccharides, proteins, DNA. Biofilms cause persisting infections associated with implanted medical devices and hospital acquired (nosocomial) infections. Catheter-associated urinary tract infections (CAUTIs) are the most common type of nosocomial infections accounting for up to 40% of all hospital acquired infections. Several different strategies, including use of antibacterial agents and genetic cues, quorum sensing, have been adopted for inhibiting biofilm formation relevant to CAUTI surfaces. Each of these methods pertains to certain types of bacteria, processes and has shortcomings. Based on eukaryotic cell topography interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, topographies tested so far have not included a systematic variation of size across basic topography shapes. In this study patterned topography was systematically varied in size and shape according to two approaches 1) confinement and 2) wetting. For the confinement approach, using scanning electron microscopy and confocal microscopy, orienting effects of tested topography based on staphylococcus aureus (s. aureus) (SH1000) and enterobacter cloacae (e. cloacae) (ATCC 700258) bacterial models were identified on features of up to 10 times the size of the bacterium. Psuedomonas aeruginosa (p. aeruginosa) (PAO1) did not show any orientational effects, under the test conditions. Another important factor in medical biofilms is the identification and quantification of phenotypic state which has not been discussed in the literature concerning bacteria topography characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference

  20. Objective computerized evaluation of normal patterns of facial muscles contraction.

    Science.gov (United States)

    Jorge Jr, Jose Jarjura; Pialarissi, Paulo Roberto; Borges, Godofredo Campos; Squella, Sara Agueda Fuenzalida; de Gouveia, Maria de Fátima; Saragiotto Jr, Jose Carlos; Gonçalves, Victor Ribeiro

    2012-04-01

    Different methods used to evaluate the movements of the face have many degrees of subjectivity and reliability. The authors discuss the ease of using these methods in clinical practice or their accuracy in scientific research. To obtain the standard for normal facial muscles movements using an objective method - the Vicon system. Light reflective markers were placed at points of interest on the face of 12 normal subjects. The movements were captured by cameras that sent the images to a computer. The points' displacements were measured between rest and maximum muscle contraction; and we calculated the means and the standard deviations (SD) were calculated. When smiling, the variation of the oral commissures was between 6.45 and 12.11 mm, mean of 9.28 mm and SD od 2.83; for lifting the eyebrow, it is between 6.0 and 13.08 mm, mean of 10.57 mm and SD of 2.51; for eyelids movement there was a variation of 6.89 and 11.29 mm, with a mean value of 9.09 mm and SD of 2.20; for the movement of wrinkling the forehead, the results showed a variation of 4.16 and 10.85 mm, with a mean value of 7.56 and SD of 3.29. The authors obtained normal patterns for facial muscle contraction.

  1. Stability on Adaptive NN Formation Control with Variant Formation Patterns and Interaction Topologies

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2008-03-01

    Full Text Available The formation task achieved by multiple robots is a tough issue in practice, because of the limitations of the sensing abilities and communicating functions among them. This paper investigates the decentralized formation control in case of parameter uncertainties, bounded disturbances, and variant interactions among robots. To design decentralized controller, a formation description is firstly proposed, which consists of two aspects in terms of formation pattern and interaction topology. Then the formation control using adaptive neural network (ANN is proposed based on the relative error derived from formation description. From the analysis on stability of the formation control under invariant/variant formation pattern and interaction topology, it is concluded that if formation pattern is of class Ck, k ≥1, and interaction graph is connected and changed with finite times, the convergence of the formation control is guaranteed, so that robots must form the formation described by the formation pattern.

  2. Stability on Adaptive NN Formation Control with Variant Formation Patterns and Interaction Topologies

    Directory of Open Access Journals (Sweden)

    Yangmin Li

    2008-11-01

    Full Text Available The formation task achieved by multiple robots is a tough issue in practice, because of the limitations of the sensing abilities and communicating functions among them. This paper investigates the decentralized formation control in case of parameter uncertainties, bounded disturbances, and variant interactions among robots. To design decentralized controller, a formation description is firstly proposed, which consists of two aspects in terms of formation pattern and interaction topology. Then the formation control using adaptive neural network (ANN is proposed based on the relative error derived from formation description. From the analysis on stability of the formation control under invariant/variant formation pattern and interaction topology, it is concluded that if formation pattern is of class kC, 1k≥ , and interaction graph is connected and changed with finite times, the convergence of the formation control is guaranteed, so that robots must form the formation described by the formation pattern.

  3. Pattern formation in rotating Bénard convection

    Science.gov (United States)

    Fantz, M.; Friedrich, R.; Bestehorn, M.; Haken, H.

    1992-12-01

    Using an extension of the Swift-Hohenberg equation we study pattern formation in the Bénard experiment close to the onset of convection in the case of rotating cylindrical fluid containers. For small Taylor numbers we emphasize the existence of slowly rotating patterns and describe behaviour exhibiting defect motion. Finally, we study pattern formation close to the Küppers-Lortz instability. The instability is nucleated at defects and proceeds through front propagation into the bulk patterns.

  4. Dislocated Tongue Muscle Attachment and Cleft Palate Formation.

    Science.gov (United States)

    Kouskoura, T; El Fersioui, Y; Angelini, M; Graf, D; Katsaros, C; Chiquet, M

    2016-04-01

    In Pierre Robin sequence, a retracted tongue due to micrognathia is thought to physically obstruct palatal shelf elevation and thereby cause cleft palate. However, micrognathia is not always associated with palatal clefting. Here, by using the Bmp7-null mouse model presenting with cleft palate and severe micrognathia, we provide the first causative mechanism linking the two. In wild-type embryos, the genioglossus muscle, which mediates tongue protrusion, originates from the rostral process of Meckel's cartilage and later from the mandibular symphysis, with 2 tendons positive for Scleraxis messenger RNA. In E13.5 Bmp7-null embryos, a rostral process failed to form, and a mandibular symphysis was absent at E17.5. Consequently, the genioglossus muscle fibers were diverted toward the lingual surface of Meckel's cartilage and mandibles, where they attached in an aponeurosis that ectopically expressed Scleraxis. The deflection of genioglossus fibers from the anterior-posterior toward the medial-lateral axis alters their direction of contraction and necessarily compromises tongue protrusion. Since this muscle abnormality precedes palatal shelf elevation, it is likely to contribute to clefting. In contrast, embryos with a cranial mesenchyme-specific deletion of Bmp7 (Bmp7:Wnt1-Cre) exhibited some degree of micrognathia but no cleft palate. In these embryos, a rostral process was present, indicating that mesenchyme-derived Bmp7 is dispensable for its formation. Moreover, the genioglossus appeared normal in Bmp7:Wnt1-Cre embryos, further supporting a role of aberrant tongue muscle attachment in palatal clefting. We thus propose that in Pierre Robin sequence, palatal shelf elevation is not impaired simply by physical obstruction by the tongue but by a specific developmental defect that leads to functional changes in tongue movements.

  5. Pattern formation by dewetting and evaporating sedimenting suspensions

    NARCIS (Netherlands)

    Habibi, M.; Moller, P.; Fall, A.; Rafaï, S.; Bonn, D.

    2012-01-01

    Pattern formation from drying droplets containing sedimenting particles and dewetting of thin films of such suspensions was studied. The dewetting causes the formation of finger-like patterns near the contact line which leave behind a deposit of branches. We find that the strikingly low speed of dew

  6. Patterns of connectivity of spinal interneurons with single muscle afferents.

    Science.gov (United States)

    Quevedo, J; Eguibar, J R; Lomeli, J; Rudomin, P

    1997-07-01

    A technique was developed to measure, in the anesthetized and paralyzed cat under artificial ventilation, changes of excitability to intraspinal stimulation simultaneously in two different afferent fibers or in two collaterals of the same afferent fiber. Intraspinal stimulation reduced the threshold of single muscle afferent fibers ending in the intermediate nucleus. This effect was seen with strengths below those required to activate the afferent fiber tested (1.5-12 microA), occurred at a short latency (1.5-2.0 ms), reached a maximum between 15 and 30 ms, and lasted up to 100 ms. The effects produced by graded stimulation applied at the shortest conditioning-testing stimulus time intervals increased by fixed steps, suggesting recruitment of discrete elements, most likely of last-order interneurons mediating primary afferent depolarization (PAD). The short-latency increases in excitability produced by the weakest effective intraspinal stimuli were usually detected only in the collateral closest to the stimulating micropipette, indicating that the stimulated interneurons mediating PAD have spatially restricted actions. The short-latency PAD produced by intraspinal stimuli, as well as the PAD produced by stimulation of the posterior biceps and semitendinosus (PBSt) nerve or by stimulation of the bulbar reticular formation (RF), was depressed 19-30 min after the i.v. injection of 0.5 mg/kg of picrotoxin, suggesting that all these effects were mediated by GABAergic mechanisms. The PAD elicited by stimulation of muscle and/or cutaneous nerves was depressed following the i.v. injection of (-)-baclofen, whereas the PAD elicited in the same collateral by stimulation of the RF was baclofen-resistant. The short-latency PAD produced by intraspinal stimulation was not always depressed by i.v. injections of (-)-baclofen. Baclofen-sensitive and baclofen-resistant monosynaptic PADs could be produced in different collaterals of the same afferent fiber. The results suggest that

  7. Regular pattern formation in real ecosystems

    NARCIS (Netherlands)

    Rietkerk, Max; Koppel, Johan van de

    2008-01-01

    Localized ecological interactions can generate striking large-scale spatial patterns in ecosystems through spatial self-organization. Possible mechanisms include oscillating consumer–resource interactions, localized disturbance-recovery processes and scale-dependent feedback. Despite abundant theore

  8. Sequential pattern formation governed by signaling gradients

    CERN Document Server

    Jörg, David J; Jülicher, Frank

    2016-01-01

    Rhythmic and sequential segmentation of the embryonic body plan is a vital developmental patterning process in all vertebrate species. However, a theoretical framework capturing the emergence of dynamic patterns of gene expression from the interplay of cell oscillations with tissue elongation and shortening and with signaling gradients, is still missing. Here we show that a set of coupled genetic oscillators in an elongating tissue that is regulated by diffusing and advected signaling molecules can account for segmentation as a self-organized patterning process. This system can form a finite number of segments and the dynamics of segmentation and the total number of segments formed depend strongly on kinetic parameters describing tissue elongation and signaling molecules. The model accounts for existing experimental perturbations to signaling gradients, and makes testable predictions about novel perturbations. The variety of different patterns formed in our model can account for the variability of segmentatio...

  9. Sequential pattern formation governed by signaling gradients

    Science.gov (United States)

    Jörg, David J.; Oates, Andrew C.; Jülicher, Frank

    2016-10-01

    Rhythmic and sequential segmentation of the embryonic body plan is a vital developmental patterning process in all vertebrate species. However, a theoretical framework capturing the emergence of dynamic patterns of gene expression from the interplay of cell oscillations with tissue elongation and shortening and with signaling gradients, is still missing. Here we show that a set of coupled genetic oscillators in an elongating tissue that is regulated by diffusing and advected signaling molecules can account for segmentation as a self-organized patterning process. This system can form a finite number of segments and the dynamics of segmentation and the total number of segments formed depend strongly on kinetic parameters describing tissue elongation and signaling molecules. The model accounts for existing experimental perturbations to signaling gradients, and makes testable predictions about novel perturbations. The variety of different patterns formed in our model can account for the variability of segmentation between different animal species.

  10. Pattern Formation in a Dusty Plasma System

    Institute of Scientific and Technical Information of China (English)

    黄峰; 叶茂福; 王龙; 江南

    2004-01-01

    A rich variety of dust patterns have been observed in a capacitively coupled rf discharge dusty plasma system. Dust particles are synthesized through chemical reaction of the filled gas mixture during discharge. Different patterns are formed in different stages of particle growth. In the early stage of particle growth, dust cloud can be formed by a large number of small particles, and its behavior appears to be fluid-like. Such interesting nonlinear phenomena as dust void and complex dust cloud patterns are observed in this stage. As dust particles grow, the particle size and structure can be controlled to follow two different routes. In one of the routes, the particles grow up in a ball-like shape and can be formed into regular lattice and cluster patterns.In the other, the particles grow up in a fractal shape.

  11. Regular pattern formation in real ecosystems

    NARCIS (Netherlands)

    Rietkerk, M.; Van de Koppel, J.

    2008-01-01

    Localized ecological interactions can generate striking large-scale spatial patterns in ecosystems through spatial self-organization. Possible mechanisms include oscillating consumer–resource interactions, localized disturbance-recovery processes and scale-dependent feedback. Despite abundant

  12. Pattern formations in chaotic spatio-temporal systems

    Indian Academy of Sciences (India)

    Ying Zhang; Shihong Wang; Jinhua Xiao; Hilda A Cerdeira; S Chen; Gang Hu

    2005-06-01

    Pattern formations in chaotic spatio-temporal systems modelled by coupled chaotic oscillators are investigated. We focus on various symmetry breakings and different kinds of chaos synchronization–desynchronization transitions, which lead to certain types of spontaneous spatial orderings and the emergence of some typical ordered patterns, such as rotating wave patterns with splay phase ordering (orientational symmetry breaking) and partially synchronous standing wave patterns with in-phase ordering (translational symmetry breaking). General pictures of the global behaviors of pattern formations and transitions in coupled chaotic oscillators are provided.

  13. Pattern formation in oscillatory media without lateral inhibition

    Science.gov (United States)

    Ali, Rehman; Harris, Jeremy; Ermentrout, Bard

    2016-07-01

    Spontaneous symmetry breaking instabilities are the most common mechanism for how biological, chemical, and physical systems produce spatial patterns. Beginning with Turing's original paper, so-called lateral inhibition—in which negative feedback has greater spread than positive feedback—has been the underlying mechanism for pattern formation in biological models. Despite this, there are many biological systems that exhibit pattern formation but do not have lateral inhibition. In this paper, we present an example of such a system that is able to generate robust patterns emerging from a spatially homogeneous state. In fact, patterns can arise when there is only spatial spread of the activator. Unlike classic Turing pattern formation, these patterns arise from a spatially homogeneous oscillation rather than from a constant steady state.

  14. Relation Between Muscle Activation Pattern and Pain : An Explorative Study in a Bassists Population

    NARCIS (Netherlands)

    Woldendorp, Kees H.; van de Werk, Pieter; Boonstra, Anne M.; Stewart, Roy E.; Otten, Egbert

    2013-01-01

    Objective: To explore the muscle activation patterns in relation to pain complaints in bassists studied during a musical task. This study was based on the assumption that pain complaints are caused by increased muscle activation during playing or relaxation and/or faster onset of fatigue of muscles.

  15. Relation Between Muscle Activation Pattern and Pain : An Explorative Study in a Bassists Population

    NARCIS (Netherlands)

    Woldendorp, Kees H.; van de Werk, Pieter; Boonstra, Anne M.; Stewart, Roy E.; Otten, Egbert

    Objective: To explore the muscle activation patterns in relation to pain complaints in bassists studied during a musical task. This study was based on the assumption that pain complaints are caused by increased muscle activation during playing or relaxation and/or faster onset of fatigue of muscles.

  16. Muscle wasting and the temporal gene expression pattern in a novel rat intensive care unit model

    Directory of Open Access Journals (Sweden)

    Llano-Diez Monica

    2011-12-01

    Full Text Available Abstract Background Acute quadriplegic myopathy (AQM or critical illness myopathy (CIM is frequently observed in intensive care unit (ICU patients. To elucidate duration-dependent effects of the ICU intervention on molecular and functional networks that control the muscle wasting and weakness associated with AQM, a gene expression profile was analyzed at time points varying from 6 hours to 14 days in a unique experimental rat model mimicking ICU conditions, i.e., post-synaptically paralyzed, mechanically ventilated and extensively monitored animals. Results During the observation period, 1583 genes were significantly up- or down-regulated by factors of two or greater. A significant temporal gene expression pattern was constructed at short (6 h-4 days, intermediate (5-8 days and long (9-14 days durations. A striking early and maintained up-regulation (6 h-14d of muscle atrogenes (muscle ring-finger 1/tripartite motif-containing 63 and F-box protein 32/atrogin-1 was observed, followed by an up-regulation of the proteolytic systems at intermediate and long durations (5-14d. Oxidative stress response genes and genes that take part in amino acid catabolism, cell cycle arrest, apoptosis, muscle development, and protein synthesis together with myogenic factors were significantly up-regulated from 5 to 14 days. At 9-14 d, genes involved in immune response and the caspase cascade were up-regulated. At 5-14d, genes related to contractile (myosin heavy chain and myosin binding protein C, regulatory (troponin, tropomyosin, developmental, caveolin-3, extracellular matrix, glycolysis/gluconeogenesis, cytoskeleton/sarcomere regulation and mitochondrial proteins were down-regulated. An activation of genes related to muscle growth and new muscle fiber formation (increase of myogenic factors and JunB and down-regulation of myostatin and up-regulation of genes that code protein synthesis and translation factors were found from 5 to 14 days. Conclusions Novel

  17. Pattern formation - Instabilities in sand ripples

    DEFF Research Database (Denmark)

    Hansen, J. L.; v. Hecke, M.; Haaning, A.

    2001-01-01

    Sand ripples are seen below shallow wavy water and are formed whenever water oscillates over a bed of sand. Here we analyse the instabilities that can upset this perfect patterning when the ripples are subjected to large changes in driving amplitude or frequency, causing them to deform both...

  18. Comparing investigation of pattern formation in glow and streamer DBD

    Science.gov (United States)

    Li, Ben; Ouyang, Jiting

    2016-11-01

    In this paper, we investigate the behaviors of patterns in dielectric barrier discharge (DBD) in glow and streamer regimes under different operating conditions (driving frequency and voltage) and external electric/magnetic field to explore the similarity and difference of pattern formation. It is found that patterns in both glow and streamer DBDs can be homogenized by decreasing the driving frequency to a low level. But filamentary streamers can still appear at low frequency when the voltage is much higher. With an additional lateral electric field, patterns in both regimes can be homogenized. However, an axial magnetic field makes the glow DBD homogeneous, while the streamer DBD decreases in filamentary size. In both regimes, dynamics and distribution of the space charges, rather than the surface charges, play the predominant role in the formation of DBD patterns. But the surface charges may also play an important role in pattern formation, especially in streamer DBD.

  19. Muscle co-contraction patterns in robot-mediated force field learning to guide specific muscle group training.

    Science.gov (United States)

    Pizzamiglio, Sara; Desowska, Adela; Shojaii, Pegah; Taga, Myriam; Turner, Duncan L

    2017-01-01

    Muscle co-contraction is a strategy of increasing movement accuracy and stability employed in dealing with force perturbation of movement. It is often seen in neuropathological populations. The direction of movement influences the pattern of co-contraction, but not all movements are easily achievable for populations with motor deficits. Manipulating the direction of the force instead, may be a promising rehabilitation protocol to train movement with use of a co-contraction reduction strategy. Force field learning paradigms provide a well described procedure to evoke and test muscle co-contraction. The aim of this study was to test the muscle co-contraction pattern in a wide range of arm muscles in different force-field directions utilising a robot-mediated force field learning paradigm of motor adaptation. Forty-two participants volunteered to participate in a study utilising robot-mediated force field motor adaptation paradigm with a clockwise or counter-clockwise force field. Kinematics and surface electromyography (EMG) of eight arm muscles were measured. Both muscle activation and co-contraction was earlier and stronger in flexors in the clockwise condition and in extensors in the counter-clockwise condition. Manipulating the force field direction leads to changes in the pattern of muscle co-contraction.

  20. Resolving Shifting Patterns of Muscle Energy Use in Swimming Fish

    Science.gov (United States)

    Gerry, Shannon P.; Ellerby, David J.

    2014-01-01

    Muscle metabolism dominates the energy costs of locomotion. Although in vivo measures of muscle strain, activity and force can indicate mechanical function, similar muscle-level measures of energy use are challenging to obtain. Without this information locomotor systems are essentially a black box in terms of the distribution of metabolic energy. Although in situ measurements of muscle metabolism are not practical in multiple muscles, the rate of blood flow to skeletal muscle tissue can be used as a proxy for aerobic metabolism, allowing the cost of particular muscle functions to be estimated. Axial, undulatory swimming is one of the most common modes of vertebrate locomotion. In fish, segmented myotomal muscles are the primary power source, driving undulations of the body axis that transfer momentum to the water. Multiple fins and the associated fin muscles also contribute to thrust production, and stabilization and control of the swimming trajectory. We have used blood flow tracers in swimming rainbow trout (Oncorhynchus mykiss) to estimate the regional distribution of energy use across the myotomal and fin muscle groups to reveal the functional distribution of metabolic energy use within a swimming animal for the first time. Energy use by the myotomal muscle increased with speed to meet thrust requirements, particularly in posterior myotomes where muscle power outputs are greatest. At low speeds, there was high fin muscle energy use, consistent with active stability control. As speed increased, and fins were adducted, overall fin muscle energy use declined, except in the caudal fin muscles where active fin stiffening is required to maintain power transfer to the wake. The present data were obtained under steady-state conditions which rarely apply in natural, physical environments. This approach also has potential to reveal the mechanical factors that underlie changes in locomotor cost associated with movement through unsteady flow regimes. PMID:25165858

  1. Resolving shifting patterns of muscle energy use in swimming fish.

    Directory of Open Access Journals (Sweden)

    Shannon P Gerry

    Full Text Available Muscle metabolism dominates the energy costs of locomotion. Although in vivo measures of muscle strain, activity and force can indicate mechanical function, similar muscle-level measures of energy use are challenging to obtain. Without this information locomotor systems are essentially a black box in terms of the distribution of metabolic energy. Although in situ measurements of muscle metabolism are not practical in multiple muscles, the rate of blood flow to skeletal muscle tissue can be used as a proxy for aerobic metabolism, allowing the cost of particular muscle functions to be estimated. Axial, undulatory swimming is one of the most common modes of vertebrate locomotion. In fish, segmented myotomal muscles are the primary power source, driving undulations of the body axis that transfer momentum to the water. Multiple fins and the associated fin muscles also contribute to thrust production, and stabilization and control of the swimming trajectory. We have used blood flow tracers in swimming rainbow trout (Oncorhynchus mykiss to estimate the regional distribution of energy use across the myotomal and fin muscle groups to reveal the functional distribution of metabolic energy use within a swimming animal for the first time. Energy use by the myotomal muscle increased with speed to meet thrust requirements, particularly in posterior myotomes where muscle power outputs are greatest. At low speeds, there was high fin muscle energy use, consistent with active stability control. As speed increased, and fins were adducted, overall fin muscle energy use declined, except in the caudal fin muscles where active fin stiffening is required to maintain power transfer to the wake. The present data were obtained under steady-state conditions which rarely apply in natural, physical environments. This approach also has potential to reveal the mechanical factors that underlie changes in locomotor cost associated with movement through unsteady flow regimes.

  2. Pattern formation in arrays of chemical oscillators

    Indian Academy of Sciences (India)

    Neeraj Kumar Kamal

    2012-05-01

    We describe a simple model mimicking diffusively coupled chemical micro-oscillators. We characterize the rich variety of dynamical states emerging from the model under variation of time delay in coupling, coupling strength and boundary conditions. The spatiotemporal patterns obtained include clustering, mixed dynamics, inhomogeneous steady states and amplitude death. Further, under delay in coupling, the model yields transitions from phase to antiphase oscillations, reminiscent of that observed in experiments [M Toiya et al, J. Chem. Lett. 1, 1241 (2010)].

  3. Changes in PAD patterns of group I muscle afferents after a peripheral nerve crush.

    Science.gov (United States)

    Enríquez, M; Jiménez, I; Rudomin, P

    1996-01-01

    In the anesthetized cat we have analyzed the changes in primary afferent depolarization (PAD) evoked in single muscle spindle and tendon organ afferents at different times after their axons were crushed in the periphery and allowed to regenerate. Medial gastrocnemius (MG) afferents were depolarized by stimulation of group I fibers in the posterior biceps and semitendinosus nerve (PBSt), as soon as 2 weeks after crushing their axons in the periphery, in some cases before they could be activated by physiological stimulation of muscle receptors. Two to twelve weeks after crushing the MG nerve, stimulation of the PBSt produced PAD in all MG fibers reconnected with presumed muscle spindles and tendon organs. The mean amplitude of the PAD elicited in afferent fibers reconnected with muscle spindles was increased relative to values obtained from Ia fibers in intact (control) preparations, but remained essentially the same in fibers reconnected with tendon organs. Quite unexpectedly, we found that, between 2 and 12 weeks after crushing the MG nerve, stimulation of the bulbar reticular formation (RF) produced PAD in most afferent fibers reconnected with muscle spindle afferents. The mean amplitude of the PAD elicited in these fibers was significantly increased relative to the PAD elicited in muscle spindle afferents from intact preparations (from 0.08 +/- 0.4 to 0.47 +/- 0.34 mV). A substantial recovery was observed between 6 months and 2.5 years after the peripheral nerve injury. Stimulation of the sural (SU) nerve produced practically no PAD in muscle spindles from intact preparations, and this remained so in those afferents reconnected with muscle spindles impaled 2-12 weeks after the nerve crush. The mean amplitude of the PAD produced in afferent fibers reconnected with tendon organs by stimulation of the PBSt nerve and of the bulbar RF remained essentially the same as the PAD elicited in intact afferents. However, SU nerve stimulation produced a larger PAD in afferents

  4. Shoulder muscle firing patterns during the windmill softball pitch.

    Science.gov (United States)

    Maffet, M W; Jobe, F W; Pink, M M; Brault, J; Mathiyakom, W

    1997-01-01

    The purpose of this study was to describe the activity of eight shoulder muscles during the windmill fast-pitch softball throw. Ten collegiate female pitchers were analyzed with intramuscular electromyography, high-speed cinematography, and motion analysis. The supraspinatus muscle fired maximally during arm elevation from the 6 to 3 o'clock position phase, centralizing the humeral head within the glenoid. The posterior deltoid and teres minor muscles acted maximally from the 3 to 12 o'clock position phase to continue arm elevation and externally rotate the humerus. The pectoralis major muscle accelerated the arm from the 12 o'clock position to ball release phase. The serratus anterior muscle characteristically acted to position the scapula for optimal glenohumeral congruency, and the subscapularis muscle functioned as an internal rotator and to protect the anterior capsule. Although the windmill softball pitch is overtly different from the baseball pitch, several surprising similarities were revealed. The serratus anterior and pectoralis major muscles work in synchrony and seem to have similar functions in both pitches. Although the infraspinatus and teres minor muscles are both posterior cuff muscles, they are characteristically uncoupled during the 6 to 3 o'clock position phase, with the infraspinatus muscle acting more independently below 90 degrees. Subscapularis muscle activity seems important in dynamic anterior glenohumeral stabilization and as an internal rotator in both the baseball and softball throws.

  5. THE CAPILLARY PATTERN IN HUMAN MASSETER MUSCLE DURING AGEING

    Directory of Open Access Journals (Sweden)

    Erika Cvetko

    2013-10-01

    Full Text Available The effect of ageing on the capillary network in skeletal muscles has produced conflicting results in both, human and animals studies. Some of the inconsistencies are due to non-comparable and biased methods that were applied on thin transversal sections, especially in muscles with complicated morphological structures, such as in human masseter muscle. We present a new immunohistochemical method for staining capillaries and muscle fibres in 100 µm thick sections as well as novel approach to 3D visualization of capillaries and muscle fibres. Applying confocal microscopy and virtual 3D stereological grids, or tracing capillaries in virtual reality, length of capillaries within a muscle volume or length of capillaries adjacent to muscle fibre per fibre length, fibre surface or fibre volume were evaluated in masseter muscle of young and old subjects by an unbiased approach. Our findings show that anatomic capillarity is well maintained in masseter muscle in old subjects; however, vascular remodelling occurs with age, which could be a response to changed muscle function and age-related muscle fibre type transformations.

  6. Embryogenesis, a process of pattern formation

    Institute of Scientific and Technical Information of China (English)

    Meng-Xiang SUN

    2011-01-01

    @@ Plant embryogenesis is traditionally defined as a develop-mental process from zygote to mature embryo, which has the potential to form a complete plant (Bhojwani, 1974; Hu,2005).In dicotyledonous species, the fertilized egg or zygote usually divides according to a stereotyped pattern and gives rise to an embryo that consists of an embryonic shoot,cotyledons, hypocotyls, and an embryonic root.Thus, the basic body plan of the plant is established during the embryogenesis.Interestingly, the shoot-leaf-stem structure,not including the root, is repeatedly photocopied as a basic unit throughout plant vegetative growth (Wolpert et al.,2002).

  7. Labyrinthine Instability and Pattern Formation in Ferrofluids

    CERN Document Server

    Harrison, Timothy J

    2012-01-01

    Ferrofluids suspended in liquids and constrained in quasi-two dimensional domains were exposed to transverse magnetic fields. The points of elliptical instability of nearly circular drops were measured and compared to the theoretical prediction using a fitting parameter. The data matched the predicted trend well for 3 different liquids used as suspensions; however, at extreme values of drop radius, there was a significant deviation from prediction. The angles at each node of the labyrinthine pattern, formed using high magnetic fields, were measured and compared with the prediction of 120 degrees. For the dense labyrinth the most common angles were between 135 degrees -144 degrees, suggesting interaction between arms were having a repelling effect causing angles to widen. For the less dense labyrinth the most frequent angle category decreased, supporting this hypothesis. In the experiments the area, which theoretically should be constant, was noticed to change and this encouraged an investigation into how the ...

  8. Pattern Formation and Quasicrystal Structure in Azobenzene Polymer Film

    Institute of Scientific and Technical Information of China (English)

    XU Ze-Da; CAI Zhi-Gang; ZHANG Ling-Zhi; LIU Yan-Fa; YANG Jie; SHE Wei-Long; ZHOU Jian-Ying

    2000-01-01

    Pattern formation in azobenzene polymer film by degenerate four-wave mixing is reported. Island arrays with specific patterns are analyzed with scanning electron microscopy and polarizing optical microscopy. It is demonstrated that the control of photo-induced nanostructure sized micropattern in the nonlinear organic film is possible by using properly polarized writing beams with the total incident power exceeding a certain threshold.

  9. The role of auxin signaling in early embryo pattern formation

    NARCIS (Netherlands)

    Smit, Margot E.; Weijers, Dolf

    2015-01-01

    Pattern formation of the early Arabidopsis embryo generates precursors to all major cell types, and is profoundly controlled by the signaling molecule auxin. Here we discuss recent milestones in our understanding of auxin-dependent embryo patterning. Auxin biosynthesis, transport and response mec

  10. Pattern formation in mutation of "Game of Life"

    Institute of Scientific and Technical Information of China (English)

    HUANG Wen-gao; PAN Zhi-geng

    2005-01-01

    This paper presents pattern formation in generalized cellular automata (GCA) by varying parameters of classic “game Experiments show the emergence of the self-organizing patterns that is analogous with life forms at the edge of chaos, which consist of certain nontrivial structure and go through periods of growth, maturity and death. We describe these experiments and discuss their potential as alternative way for creating artificial life and generative art, and as a new method for pattern genesis.

  11. Is Team Formation Gender Neutral? Evidence from Coauthorship Patterns

    OpenAIRE

    Boschini, Anne; Sjögren, Anna

    2006-01-01

    We investigate if voluntary team formation is gender neutral. To this end, we model team formation as a random matching process influenced by the agents' preferences for team size and gender composition and derive how team formation depends on the gender ratio in the population of prospective team mates. We then test if the coauthorship pattern in articles published 1991-2002 in three top Economics journals is gender neutral, exploiting the variation in female presence across subfields of Eco...

  12. On pattern formation in ferrocolloid convection

    Energy Technology Data Exchange (ETDEWEB)

    Bozhko, A [Department of Physics, Perm State University, Bukirev Str. 15, 614990 Perm (Russian Federation); Putin, G [Department of Physics, Perm State University, Bukirev Str. 15, 614990 Perm (Russian Federation); Tynjaelae, T [Department of Energy and Environmental Technology, Lappeenranta University of Technology, 53851 Lappeenranta (Finland); Meshin, M Dabagh [Department of Energy and Environmental Technology, Lappeenranta University of Technology, 53851 Lappeenranta (Finland); Jalali, P [Department of Energy and Environmental Technology, Lappeenranta University of Technology, 53851 Lappeenranta (Finland)

    2007-04-15

    Experimental studies and numerical simulations of stability of buoyancy-driven flows in a ferrocolloid for the cases of horizontal and inclined vertical orientation of a thin cylindrical cavity are performed. The influence of a homogeneous longitudinal magnetic field on convective instability and spatio-temporal patterns were also investigated. In the case of ferrocolloids the gradients of magnetic permeability may arise due to both temperature and particle concentration gradients. The particle mass flux in a classical form is summarized from the translation diffusion coefficient and the thermal diffusion ratio. However, the explanation for the observed self-oscillation regimes in magnetic fluid for the cavities of sufficiently large thickness is conditioned by the competition of density variations originating from the fluid thermal expansion and barometric sedimentation. The results prove that a uniform longitudinal magnetic field allows to control the stability and the shape of secondary convection motions at inclined orientation of layer. In a ferrocolloid the repeated transients involving localized roll convection and pure shear flow took place. Under action of uniform longitudinal magnetic field orientated perpendicular to flux velocity of shear motion on such long-wave transients can lead to complicated types of chaotic localized states or solitary vortices.

  13. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

    Science.gov (United States)

    Alves-Pinto, Ana; Blumenstein, Tobias; Turova, Varvara; Lampe, Renée

    2016-01-01

    Objective Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP). However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility. Methods Electromyographic (EMG) recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions. Results Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation pattern correlated significantly with the degree of spasticity. Conclusion This study confirmed the occurrence of altered lower leg muscle activation patterns in patients with CP during cycling on a recumbent ergometer. There is a need to develop feedback systems that can inform patients and therapists of an incorrect muscle activation during cycling and support the training

  14. Vascular tissue differentiation and pattern formation in plants.

    Science.gov (United States)

    Ye, Zheng-Hua

    2002-01-01

    Vascular tissues, xylem and phloem, are differentiated from meristematic cells, procambium, and vascular cambium. Auxin and cytokinin have been considered essential for vascular tissue differentiation; this is supported by recent molecular and genetic analyses. Xylogenesis has long been used as a model for study of cell differentiation, and many genes involved in late stages of tracheary element formation have been characterized. A number of mutants affecting vascular differentiation and pattern formation have been isolated in Arabidopsis. Studies of some of these mutants have suggested that vascular tissue organization within the bundles and vascular pattern formation at the organ level are regulated by positional information.

  15. Intra-session repeatability of lower limb muscles activation pattern during pedaling.

    Science.gov (United States)

    Dorel, Sylvain; Couturier, Antoine; Hug, François

    2008-10-01

    Assessment of intra-session repeatability of muscle activation pattern is of considerable relevance for research settings, especially when used to determine changes over time. However, the repeatability of lower limb muscles activation pattern during pedaling is not fully established. Thus, we tested the intra-session repeatability of the activation pattern of 10 lower limb muscles during a sub-maximal cycling exercise. Eleven triathletes participated to this study. The experimental session consisted in a reference sub-maximal cycling exercise (i.e. 150 W) performed before and after a 53-min simulated training session (mean power output=200+/-12 W). Repeatability of EMG patterns was assessed in terms of muscle activity level (i.e. RMS of the mean pedaling cycle and burst) and muscle activation timing (i.e. onset and offset of the EMG burst) for the 10 following lower limb muscles: gluteus maximus (GMax), semimembranosus (SM), Biceps femoris (BF), vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), gastrocnemius medianus (GM) and lateralis (GL), soleus (SOL) and tibialis anterior (TA). No significant differences concerning the muscle activation level were found between test and retest for all the muscles investigated. Only VM, SOL and TA showed significant differences in muscle activation timing parameters. Whereas ICC and SEM values confirmed this weak repeatability, cross-correlation coefficients suggest a good repeatability of the activation timing parameters for all the studied muscles. Overall, the main finding of this work is the good repeatability of the EMG pattern during pedaling both in term of muscle activity level and muscle activation timing.

  16. Coordination patterns of shoulder muscles during level-ground and incline wheelchair propulsion.

    Science.gov (United States)

    Qi, Liping; Wakeling, James; Grange, Simon; Ferguson-Pell, Martin

    2013-01-01

    The aim of this study was to investigate how the coordination patterns of shoulder muscles change with level-ground and incline wheelchair propulsion. Wheelchair kinetics and electromyography (EMG) activity of seven muscles were recorded with surface electrodes for 15 nondisabled subjects during wheelchair propulsion on a stationary ergometer and wooden ramp (4 degree slope). Kinetic data were measured by a SmartWheel. The kinetics variables and the onset, cessation, and duration of EMG activity from seven muscles were compared with paired t-tests for two sessions. Muscle coordination patterns across seven muscles were analyzed by principal component analysis. Push forces on the push rim and the percentage of push phase in the cycle increased significantly during incline propulsion. Propulsion condition and posture affected muscle coordination patterns. During incline propulsion, there was more intense and longer EMG activity of push muscles in the push phase and less EMG activity of the recovery muscles, which corresponded with the increased kinetic data total force output and longer push phase in the incline condition. This work establishes a framework for developing a performance feedback system for wheelchair users to better coordinate their muscle patterning activity.

  17. Thoracic posture, shoulder muscle activation patterns and isokinetic ...

    African Journals Online (AJOL)

    determined at 60°/sec by measuring the concentric and eccentric forces during internal rotation (IR) and ... muscle was observed prior to impact, compared with the pectoralis major ... tight shoulder internal rotators and adductors, high body mass and ..... EMG analysis of rugby players' scapulothoracic muscles is limited, but.

  18. Argon ion beam induced surface pattern formation on Si

    Energy Technology Data Exchange (ETDEWEB)

    Hofsäss, H.; Bobes, O.; Zhang, K. [2nd Institute of Physics, Faculty of Physics, University Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

    2016-01-21

    The development of self-organized surface patterns on Si due to noble gas ion irradiation has been studied extensively in the past. In particular, Ar ions are commonly used and the pattern formation was analyzed as function of ion incidence angle, ion fluence, and ion energies between 250 eV and 140 keV. Very few results exist for the energy regime between 1.5 keV and 10 keV and it appears that pattern formation is completely absent for these ion energies. In this work, we present experimental data on pattern formation for Ar ion irradiation between 1 keV and 10 keV and ion incidence angles between 50° and 75°. We confirm the absence of patterns at least for ion fluences up to 10{sup 18} ions/cm{sup 2}. Using the crater function formalism and Monte Carlo simulations, we calculate curvature coefficients of linear continuum models of pattern formation, taking into account contribution due to ion erosion and recoil redistribution. The calculations consider the recently introduced curvature dependence of the erosion crater function as well as the dynamic behavior of the thickness of the ion irradiated layer. Only when taking into account these additional contributions to the linear theory, our simulations clearly show that that pattern formation is strongly suppressed between about 1.5 keV and 10 keV, most pronounced at 3 keV. Furthermore, our simulations are now able to predict whether or not parallel oriented ripple patterns are formed, and in case of ripple formation the corresponding critical angles for the whole experimentally studied energies range between 250 eV and 140 keV.

  19. Laser-induced pattern formation from homogeneous polyisoprene solutions

    Institute of Scientific and Technical Information of China (English)

    Lin Dian-Yang; Li Ming; Wang Shu-Jie; Lü Zhi-Wei

    2008-01-01

    This paper reports that the pattern formation in homogeneous solutions of polyisoprene in toluene saturated with C60 induced by a continuous-wave visible laser is observed experimentally. The transmitted beam patterns change with the increase of the laser irradiation time. In the initial phase, the patterns with concentric ring-shaped structure are formed. In the end, the patterns become speckle-shaped. The incubation time of the transmitted beam widening is inversely proportional to the laser power density and solution concentration. The pattern formation results from the optical-field-induced refractive index changes in the solutions, but the mechanism of optical-field-induced refractive index changes in the polymer solutions needs to be further studied.

  20. The activity pattern of shoulder muscles in subjects with and without subacromial impingement

    DEFF Research Database (Denmark)

    Diederichsen, Louise Pyndt; Nørregaard, Jesper; Dyhre-Poulsen, Poul

    2009-01-01

    motion. In the symptomatic shoulder, there was a significantly greater EMG activity during abduction in the supraspinatus and latissimus muscles and less activity in serratus anterior compared to the healthy subjects. During external rotation, there was significantly less activity of the infraspinatus...... and serratus anterior muscles on the symptomatic side compared to the healthy subjects. On the asymptomatic side, the groups showed different muscle activity during external rotation. Our findings of an altered shoulder muscle activity pattern on both the symptomatic and asymptomatic side in patients indicate...... in patients with SI. The aim of the study was to determine and compare the activity pattern of the shoulder muscles in subjects with and without SI. Twenty-one subjects with SI and 20 healthy controls were included. Electromyography (EMG) was assessed from eight shoulder muscles from both shoulders during...

  1. The influence of wheelchair propulsion hand pattern on upper extremity muscle power and stress.

    Science.gov (United States)

    Slowik, Jonathan S; Requejo, Philip S; Mulroy, Sara J; Neptune, Richard R

    2016-06-14

    The hand pattern (i.e., full-cycle hand path) used during manual wheelchair propulsion is frequently classified as one of four distinct hand pattern types: arc, single loop, double loop or semicircular. Current clinical guidelines recommend the use of the semicircular pattern, which is based on advantageous levels of broad biomechanical metrics implicitly related to the demand placed on the upper extremity (e.g., lower cadence). However, an understanding of the influence of hand pattern on specific measures of upper extremity muscle demand (e.g., muscle power and stress) is needed to help make such recommendations, but these quantities are difficult and impractical to measure experimentally. The purpose of this study was to use musculoskeletal modeling and forward dynamics simulations to investigate the influence of the hand pattern used on specific measures of upper extremity muscle demand. The simulation results suggest that the double loop and semicircular patterns produce the most favorable levels of overall muscle stress and total muscle power. The double loop pattern had the lowest full-cycle and recovery-phase upper extremity demand but required high levels of muscle power during the relatively short contact phase. The semicircular pattern had the second-lowest full-cycle levels of overall muscle stress and total muscle power, and demand was more evenly distributed between the contact and recovery phases. These results suggest that in order to decrease upper extremity demand, manual wheelchair users should consider using either the double loop or semicircular pattern when propelling their wheelchairs at a self-selected speed on level ground.

  2. The variability of co-activation pattern of antagonist muscles in human infant crawling.

    Science.gov (United States)

    Xiong, Qi L; Wu, Xiao Y; Nong Xiao; Zeng, Si Y; Zheng, Xiao L; Di Wu; Hou, Wen S

    2016-08-01

    Infant crawling is part of normal human gross motor development, and a 4-beat gait that involves rhythmical flexion and extension of limbs and the underlying muscle co-activation of antagonist muscle around the joint. However, detection the co-activation pattern of antagonist muscle are sparse due to the general difficulty of measuring locomotion in human infants. In this paper, sEMG of antagonist muscles and the corresponding kinematics data of limbs were collected when infants were crawling on hands and knees at their self-selected speed. The infant's gross motor developmental status was assessed by the global Gross Motor Function Measure Scale (GMFM-88) as well. The method based on EMG-EMG plots was used to quantify the variability of co-activation pattern of antagonist muscle. After that, we observed that antagonist muscles of upper limb (triceps brachii and biceps brachii) showed less variability of co-activation pattern of muscles than lower limb(quadriceps femoris and hamstrings) during crawling, and this variability was also varied in different crawling phases (stance and swing). Furthermore, we found some varied behaviors in the co-activation patterns of antagonist muscles when gross motor developmental level increased. The preliminary work suggests that such adaptive changes may be related to the adjustment of neuromuscular in the early stage of gross motor development.

  3. Weakening iliopsoas muscle in healthy adults may induce stiff knee pattern

    Directory of Open Access Journals (Sweden)

    N. Ekin Akalan

    2016-12-01

    Conclusion: These findings verify that any treatment protocol that slows hip flexion during gait by weakening iliopsoas muscle may have great potential to produce SKG pattern combined with reduced gait velocity.

  4. Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders

    Directory of Open Access Journals (Sweden)

    Jia Fang

    2016-01-01

    Conclusions: The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders, and may aid in distinguishing between ALS and mimic disorders.

  5. Vegetation pattern formation of a water-biomass model

    Science.gov (United States)

    Wang, Xiaoli; Wang, Wendi; Zhang, Guohong

    2017-01-01

    In this paper, a mathematical model with diffusion and cross-diffusion is proposed to describe the interaction between the vegetation and the soil water. Based on the view of Turing pattern, we discuss the conditions of the diffusion-induced instability and the cross-diffusion-induced instability of a homogenous uniform steady state. We find that either a fast diffusion speed of water or a great hydraulic diffusivity due to the suction of roots may drive the instability of the homogenous steady state. Furthermore, we find that both the rain-fall rate and the infiltration feedback parameter can induce the transitions among the vegetation state, pattern formation and bare soil state. It is also found that the "terrain slope" may cause the instability of the homogenous steady state and drive the formation of periodic stripe pattern. Consequently, the diversity of dryland vegetation in reality can be explained as a result of pattern solutions of the model.

  6. On the mechanical theory for biological pattern formation

    Science.gov (United States)

    Bentil, D. E.; Murray, J. D.

    1993-02-01

    We investigate the pattern-forming potential of mechanical models in embryology proposed by Oster, Murray and their coworkers. We show that the presence of source terms in the tissue extracellular matrix and cell density equations give rise to spatio-temporal oscillations. An extension of one such model to include ‘biologically realistic long range effects induces the formation of stationary spatial patterns. Previous attempts to solve the full system were in one dimension only. We obtain solutions in one dimension and extend our simulations to two dimensions. We show that a single mechanical model alone is capable of generating complex but regular spatial patterns rather than the requirement of model interaction as suggested by Nagorcka et al. and Shaw and Murray. We discuss some biological applications of the models among which are would healing and formation of dermatoglyphic (fingerprint) patterns.

  7. Phyllotactic pattern formation in early stages of cactus ontogeny

    Directory of Open Access Journals (Sweden)

    Edyta M. Gola

    2011-01-01

    Full Text Available Representatives of the family Cactaceae are characterized by a wide range of phyllotaxis. To assess the origin of this diversity, early stages of phyllotactic pattern formation were examined in seedlings. The analysis of the sequence of areole initiation revealed intertribal differences. In seedlings from the Trichocereeae (Gymnocalycium, Rebutia and Notocacteae (Parodia tribes, two opposite cotyledonal areoles developed as the first elements of a pattern. Usually, next pair of areoles was initiated perpendicularly to cotyledonal areoles, starting the decussate pattern. This pattern was subsequently transformed into bijugate or into simple spiral phyllotaxis. In seedlings from the Cacteae tribe (Mammillaria and Thelocactus, cotyledonal areoles were never observed and the first areoles always appeared in the space between cotyledons. It was either areole pair (mainly in Mammillaria, starting a decussate pattern, or a single areole (mainly in Thelocactus quickly followed by areoles spirally arranged, usually in accordance with the main Fibonacci phyllotaxis. Differences in the initial stages of pattern formation do not fully explain the phyllotaxis diversity in mature cacti. Only two, the most common phyllotactic patterns occurred in the early development of studied seedlings, i.e. the main Fibonacci and the decussate pattern. Discrepancy in the range of phyllotactic spectra in seedlings and in mature plants suggests that phyllotaxis diversity emerges during further plant growth. Initial phyllotactic transformations, occurring already in the very early stages, indicate great plasticity of cactus growth and seem to support the hypothesis of the ontogenetic increase of phyllotaxis diversity due to transformations.

  8. What triggers the aerobic dive limit? Patterns of muscle oxygen depletion during dives of emperor penguins.

    Science.gov (United States)

    Williams, Cassondra L; Meir, Jessica U; Ponganis, Paul J

    2011-06-01

    The physiological basis of the aerobic dive limit (ADL), the dive duration associated with the onset of post-dive blood lactate elevation, is hypothesized to be depletion of the muscle oxygen (O(2)) store. A dual wavelength near-infrared spectrophotometer was developed and used to measure myoglobin (Mb) O(2) saturation levels in the locomotory muscle during dives of emperor penguins (Aptenodytes forsteri). Two distinct patterns of muscle O(2) depletion were observed. Type A dives had a monotonic decline, and, in dives near the ADL, the muscle O(2) store was almost completely depleted. This pattern of Mb desaturation was consistent with lack of muscle blood flow and supports the hypothesis that the onset of post-dive blood lactate accumulation is secondary to muscle O(2) depletion during dives. The mean type A Mb desaturation rate allowed for calculation of a mean muscle O(2) consumption of 12.4 ml O(2) kg(-1) muscle min(-1), based on a Mb concentration of 6.4 g 100 g(-1) muscle. Type B desaturation patterns demonstrated a more gradual decline, often reaching a mid-dive plateau in Mb desaturation. This mid-dive plateau suggests maintenance of some muscle perfusion during these dives. At the end of type B dives, Mb desaturation rate increased and, in dives beyond the ADL, Mb saturation often reached near 0%. Thus, although different physiological strategies may be used during emperor penguin diving, both Mb desaturation patterns support the hypothesis that the onset of post-dive lactate accumulation is secondary to muscle O(2) store depletion.

  9. Conserved and muscle-group-specific gene expression patterns shape postnatal development of the novel extraocular muscle phenotype.

    Science.gov (United States)

    Cheng, Georgiana; Merriam, Anita P; Gong, Bendi; Leahy, Patrick; Khanna, Sangeeta; Porter, John D

    2004-07-08

    Current models in skeletal muscle biology do not fully account for the breadth, causes, and consequences of phenotypic variation among skeletal muscle groups. The muscle allotype concept arose to explain frank differences between limb, masticatory, and extraocular (EOM) muscles, but there is little understanding of the developmental regulation of the skeletal muscle phenotypic range. Here, we used morphological and DNA microarray analyses to generate a comprehensive temporal profile for rat EOM development. Based upon coordinate regulation of morphologic/gene expression traits with key events in visual, vestibular, and oculomotor system development, we propose a model that the EOM phenotype is a consequence of extrinsic factors that are unique to its local environment and sensory-motor control system, acting upon a novel myoblast lineage. We identified a broad spectrum of differences between the postnatal transcriptional patterns of EOM and limb muscle allotypes, including numerous transcripts not traditionally associated with muscle fiber/group differences. Several transcription factors were differentially regulated and may be responsible for signaling muscle allotype specificity. Significant differences in cellular energetic mechanisms defined the EOM and limb allotypes. The allotypes were divergent in many other functional transcript classes that remain to be further explored. Taken together, we suggest that the EOM allotype is the consequence of tissue-specific mechanisms that direct expression of a limited number of EOM-specific transcripts and broader, incremental differences in transcripts that are conserved by the two allotypes. This represents an important first step in dissecting allotype-specific regulatory mechanisms that may, in turn, explain differential muscle group sensitivity to a variety of metabolic and neuromuscular diseases.

  10. Influence of different control strategies on muscle activation patterns in trunk muscles.

    Science.gov (United States)

    Hansen, Laura; Anders, Christoph

    2014-12-01

    Adequate training of the trunk muscles is essential to prevent low back pain. Although sit-ups are simple to perform, the perceived high effort is the reason why training the abdominal muscles is seldom continued over a longer period of time. It is well known that the abdominal muscles are inferior to the back muscles in terms of force, but this cannot explain the extreme difference in perceived effort between trunk flexion and extension tasks. Therefore, this study was aimed at the identification of control strategy influences on the muscular stress level. Thirty-nine subjects were investigated. The performed tasks were restricted to the sagittal plane and were implemented with simulated and realized tilt angles. Subjects were investigated in an upright position with their lower bodies fixed and their upper bodies free. Posture-controlled tasks involved graded forward and backward tilting, while force-controlled tasks involved the application of force based on a virtual tilt angle. The Surface EMG (SEMG) was taken from five trunk muscles on both sides. Control strategies seemed to have no systematic influence on the SEMG amplitudes of the back muscles. In contrast, the abdominal muscles exhibited significantly higher stress levels under posture-controlled conditions without relevantly increasing antagonistic co-activation of back muscles. The abdominal muscles' relative differences ranged from an average of 20% for the external oblique abdominal muscle to approximately 40% for the rectus abdominal muscle. The perceived high effort expended during sit-ups can now be explained by the posture-controlled contractions that are required.

  11. Dynamic formation of microenvironments at the myotendinous junction correlates with muscle fiber morphogenesis in zebrafish

    OpenAIRE

    Snow, Chelsi J.; Henry, Clarissa A.

    2008-01-01

    Muscle development involves the specification and morphogenesis of muscle fibers that attach to tendons. After attachment, muscles and tendons then function as an integrated unit to transduce force to the skeletal system and stabilize joints. The attachment site is the myotendinous junction, or MTJ, and is the primary site of force transmission. We find that attachment of fast-twitch myofibers to the MTJ correlates with the formation of novel microenvironments within the MTJ. The expression o...

  12. Spongiosa Primary Development: A Biochemical Hypothesis by Turing Patterns Formations

    Science.gov (United States)

    López-Vaca, Oscar Rodrigo; Garzón-Alvarado, Diego Alexander

    2012-01-01

    We propose a biochemical model describing the formation of primary spongiosa architecture through a bioregulatory model by metalloproteinase 13 (MMP13) and vascular endothelial growth factor (VEGF). It is assumed that MMP13 regulates cartilage degradation and the VEGF allows vascularization and advances in the ossification front through the presence of osteoblasts. The coupling of this set of molecules is represented by reaction-diffusion equations with parameters in the Turing space, creating a stable spatiotemporal pattern that leads to the formation of the trabeculae present in the spongy tissue. Experimental evidence has shown that the MMP13 regulates VEGF formation, and it is assumed that VEGF negatively regulates MMP13 formation. Thus, the patterns obtained by ossification may represent the primary spongiosa formation during endochondral ossification. Moreover, for the numerical solution, we used the finite element method with the Newton-Raphson method to approximate partial differential nonlinear equations. Ossification patterns obtained may represent the primary spongiosa formation during endochondral ossification. PMID:23193429

  13. Spongiosa Primary Development: A Biochemical Hypothesis by Turing Patterns Formations

    Directory of Open Access Journals (Sweden)

    Oscar Rodrigo López-Vaca

    2012-01-01

    Full Text Available We propose a biochemical model describing the formation of primary spongiosa architecture through a bioregulatory model by metalloproteinase 13 (MMP13 and vascular endothelial growth factor (VEGF. It is assumed that MMP13 regulates cartilage degradation and the VEGF allows vascularization and advances in the ossification front through the presence of osteoblasts. The coupling of this set of molecules is represented by reaction-diffusion equations with parameters in the Turing space, creating a stable spatiotemporal pattern that leads to the formation of the trabeculae present in the spongy tissue. Experimental evidence has shown that the MMP13 regulates VEGF formation, and it is assumed that VEGF negatively regulates MMP13 formation. Thus, the patterns obtained by ossification may represent the primary spongiosa formation during endochondral ossification. Moreover, for the numerical solution, we used the finite element method with the Newton-Raphson method to approximate partial differential nonlinear equations. Ossification patterns obtained may represent the primary spongiosa formation during endochondral ossification.

  14. Respiratory pattern changes produced by intercostal muscle/rib vibration.

    Science.gov (United States)

    Bolser, D C; Lindsey, B G; Shannon, R

    1988-06-01

    Large-amplitude vibration of the intercostal muscles/ribs has an inhibitory effect on inspiratory motor output. This effect has been attributed, in part, to the stimulation of intercostal muscle tendon organs. Intercostal muscle/rib vibration can also produce a decrease or increase in respiratory frequency. Studies were conducted 1) to determine whether, in addition to intercostal tendon organs, costovertebral joint mechanoreceptors (CVJR's) contribute to the inspiratory inhibitory effect of intercostal muscle/rib vibration (IMV) and 2) to explain the different respiratory frequency responses to IMV previously reported. Phrenic (C5) activity was monitored in paralyzed thoracotomized, artificially ventilated cats. Vibration (125 Hz) at amplitudes greater than 1,200 micron of one T6 intercostal space in decerebrated vagotomized rats reduced phrenic activity. This response was still present but weaker in some animals after denervation of the T6 intercostal muscles. Subsequent denervation of the T6 CVJR's by dorsal root sections eliminated this effect. Respiratory frequency decreased during simultaneous vibration (greater than 1,200 micron) of the T5 and T7 intercostal spaces in vagotomized cats. Respiratory frequency increased during IMV of two intercostal spaces (greater than 1,300 micron) in vagal intact cats. The use of different anesthetics (pentobarbital, allobarbital) did not alter these results. We conclude that CVJR's may contribute to the inhibitory effect of IMV on medullary inspiratory activity. The presence or absence of pulmonary vagal afferents can account for the different respiratory frequency responses to IMV, and different anesthetics did not influence these results.

  15. Variable optimization for the formation of three-dimensional self-organized heart muscle.

    Science.gov (United States)

    Khait, Luda; Hodonsky, Chani J; Birla, Ravi K

    2009-12-01

    Cardiac tissue-engineering research is focused on the development of functional three-dimensional (3D) heart muscle in vitro. These models allow the detailed study of critical events in organogenesis, such as the establishment of cell-cell communication and construction and modification of the extracellular matrix. We have previously described a model for 3D heart muscle, termed cardioids, formed by the spontaneous delamination of a cohesive monolayer of primary cells in the absence of any synthetic scaffolding material. In an earlier publication, we have shown that, upon electrical stimulation, cardioids generate a twitch force in the range of 200-300 microN, generate a specific force (twitch force normalized to total cross-sectional area) of 2-4 kN/m(2), and can be electrically paced at frequencies of up to 10 Hz without any notable fatigue. We have two objectives for the current study: model development and model optimization. Our model development efforts are focused on providing additional characterization of the cardioid model. In this study, we show for the first time that cardioids show a pattern of gene expression comparable to that of cells cultured in two dimensions on tissue culture plastic and normal mammalian heart muscle. Compared with primary cardiac cells cultured on tissue culture plastic, the expression of alpha-myosin heavy chain (MHC), beta-MHC, SERCA2, and phospholamban was significantly higher in cardioids. Our second objective, model optimization, is focused on evaluating the effect of several cell culture variables on cardioid formation and function. Specifically, we looked at the effect of plating density (1.0-4.0 x 10(6) cells per cardioid), concentration of two adhesion proteins (laminin at 0.2-2.0 microg/cm(2) and fibronectin at 1-10 microg/cm(2)), myocyte purity (using preplating times of 15 and 60 min), and ascorbic acid stimulation (1-100 microl/ml). For our optimization studies, we utilized twitch force in response to electrical

  16. Re-patterning of skeletal muscle energy metabolism by fat storage-inducing transmembrane protein 2.

    Science.gov (United States)

    Miranda, Diego A; Koves, Timothy R; Gross, David A; Chadt, Alexandra; Al-Hasani, Hadi; Cline, Gary W; Schwartz, Gary J; Muoio, Deborah M; Silver, David L

    2011-12-09

    Triacylglyceride stored in cytosolic lipid droplets (LDs) constitutes a major energy reservoir in most eukaryotes. The regulated turnover of triacylglyceride in LDs provides fatty acids for mitochondrial β-oxidation and ATP generation in physiological states of high demand for energy. The mechanisms for the formation of LDs in conditions of energy excess are not entirely understood. Fat storage-inducing transmembrane protein 2 (FIT2/FITM2) is the anciently conserved member of the fat storage-inducing transmembrane family of proteins implicated to be important in the formation of LDs, but its role in energy metabolism has not been tested. Here, we report that expression of FIT2 in mouse skeletal muscle had profound effects on muscle energy metabolism. Mice with skeletal muscle-specific overexpression of FIT2 (CKF2) had significantly increased intramyocellular triacylglyceride and complete protection from high fat diet-induced weight gain due to increased energy expenditure. Mass spectrometry-based metabolite profiling suggested that CKF2 skeletal muscle had increased oxidation of branched chain amino acids but decreased oxidation of fatty acids. Glucose was primarily utilized in CKF2 muscle for synthesis of the glycerol backbone of triacylglyceride and not for glycogen production. CKF2 muscle was ATP-deficient and had activated AMP kinase. Together, these studies indicate that FIT2 expression in skeletal muscle plays an unexpected function in regulating muscle energy metabolism and indicates an important role for lipid droplet formation in this process.

  17. Temperature Controlled Lateral Pattern Formation in Confined Polymer Thin Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao-li; David G. Bucknall

    2004-01-01

    The thermal induced topography change in a model system consisting of a polymer film on a Si substrate capped by a thin metal layer has been studied by using AFM. Regular lateral patterns over large areas were observed on the surface when the system was heated to a sufficiently high temperature. 2D-FFT analysis to the AFM images indicates that the patterns are isotropic and have well defined periodicities. The periodicities of the characteristic patterns are found to depend strongly on the annealing temperature. The study of the kinetics of the formation reveals that such a topography forms almost instantaneously once the critical temperature is reached. It is suggested that this wave-like surface morphology is driven by the thermal expansion coefficient mismatch of the different layers. This method for generating regular wave-like patterns could be used as a general method for patterning various organic materials into micro/nanostructures.

  18. Histochemical pattern of gastrocnemius muscle in fluoride toxicity syndrome

    Institute of Scientific and Technical Information of China (English)

    Shashi A; Bhushan B; Bhardwaj M

    2010-01-01

    Objective:To evaluate the effect of sodium fluoride (NaF) on cytochemical distribution of proteins, DNA, and RNA in the gastrocnemius muscle of rat in experimental fluorosis.Methods:Young Sprague Dawley albino rats were administered with NaF at 30, 45, and 75 mg/kg bw/day subcutaneously for 15 and 30 days, respectively. The control animals were given the vehicle (1cc deionized double distilled water/kg bw/day).Results: In the first phase of 15 days experimentation, the gastrocnemius muscle of rats intoxicated with NaF at 30, 45, and 75 mg /kg bw/ day showed decline in proteins includingαamino acids as compared to control. In the second phase of 30 days experimentation, the muscle fibers of rat showed elevation in sarcolemmal and sarcoplasmic proteins in 30 mg NaF dose group, and angulated fibers exhibited increase in sarcolemmal proteins in 45 mg NaF group. The marginal regions of angular and rim fibers showed deeply stained rings of sarcoplasmic proteins whereas the split fibers were faintly stained in rats treated with NaF at 75 mg/kg bw/day for 30 days. In rats treated with NaF at 30 mg/kg bw/day for 15 days, the hypertrophied peripheral muscle fibers contained more DNA, however the atrophied fibers had more RNA. In 45 mg NaF group, RNA was located in sarcolemmal regions, while DNA content decreased as compared to control. In 75 mg NaF group, the muscle fibers had dark and light staining regions of DNA and RNA. In the 30 days of experimentation, the DNA level decreased whereas RNA content increased in the gastrocnemius muscle fibers of the rat treated with NaF at 30 mg/kg bw/day. In treatment group with NaF at 45 mg/kg bw/day, the RNA content slightly declined in comparison to control, in all treatments for 15 days as well as in treatment group with NaF at 30 mg/kg bw/day for 30 days whereas the amount of DNA slightly increased as compared to treatment group with NaF at 75 mg/kg bw/day for 15 days. The highest dose group revealed elevated amount of RNA whereas

  19. Muscle Gene Expression Patterns in Human Rotator Cuff Pathology

    Science.gov (United States)

    Choo, Alexander; McCarthy, Meagan; Pichika, Rajeswari; Sato, Eugene J.; Lieber, Richard L.; Schenk, Simon; Lane, John G.; Ward, Samuel R.

    2014-01-01

    Background: Rotator cuff pathology is a common source of shoulder pain with variable etiology and pathoanatomical characteristics. Pathological processes of fatty infiltration, muscle atrophy, and fibrosis have all been invoked as causes for poor outcomes after rotator cuff tear repair. The aims of this study were to measure the expression of key genes associated with adipogenesis, myogenesis, and fibrosis in human rotator cuff muscle after injury and to compare the expression among groups of patients with varied severities of rotator cuff pathology. Methods: Biopsies of the supraspinatus muscle were obtained arthroscopically from twenty-seven patients in the following operative groups: bursitis (n = 10), tendinopathy (n = 7), full-thickness rotator cuff tear (n = 8), and massive rotator cuff tear (n = 2). Quantitative polymerase chain reaction (qPCR) was performed to characterize gene expression pathways involved in myogenesis, adipogenesis, and fibrosis. Results: Patients with a massive tear demonstrated downregulation of the fibrogenic, adipogenic, and myogenic genes, indicating that the muscle was not in a state of active change and may have difficulty responding to stimuli. Patients with a full-thickness tear showed upregulation of fibrotic and adipogenic genes; at the tissue level, these correspond to the pathologies most detrimental to outcomes of surgical repair. Patients with bursitis or tendinopathy still expressed myogenic genes, indicating that the muscle may be attempting to accommodate the mechanical deficiencies induced by the tendon tear. Conclusions: Gene expression in human rotator cuff muscles varied according to tendon injury severity. Patients with bursitis and tendinopathy appeared to be expressing pro-myogenic genes, whereas patients with a full-thickness tear were expressing genes associated with fatty atrophy and fibrosis. In contrast, patients with a massive tear appeared to have downregulation of all gene programs except inhibition of

  20. Altered motor unit discharge patterns in paretic muscles of stroke survivors assessed using surface electromyography

    Science.gov (United States)

    Hu, Xiaogang; Suresh, Aneesha K.; Rymer, William Z.; Suresh, Nina L.

    2016-08-01

    Objective. Hemispheric stroke survivors often show impairments in voluntary muscle activation. One potential source of these impairments could come from altered control of muscle, via disrupted motor unit (MU) firing patterns. In this study, we sought to determine whether MU firing patterns are modified on the affected side of stroke survivors, as compared with the analogous contralateral muscle. Approach. Using a novel surface electromyogram (EMG) sensor array, coupled with advanced template recognition software (dEMG) we recorded surface EMG signals over the first dorsal interosseous (FDI) muscle on both paretic and contralateral sides. Recordings were made as stroke survivors produced isometric index finger abductions over a large force range (20%-60% of maximum). Utilizing the dEMG algorithm, MU firing rates, recruitment thresholds, and action potential amplitudes were estimated for concurrently active MUs in each trial. Main results. Our results reveal significant changes in the firing rate patterns in paretic FDI muscle, in that the discharge rates, characterized in relation to recruitment force threshold and to MU size, were less clearly correlated with recruitment force than in contralateral FDI muscles. Firing rates in the affected muscle also did not modulate systematically with the level of voluntary muscle contraction, as would be expected in intact muscles. These disturbances in firing properties also correlated closely with the impairment of muscle force generation. Significance. Our results provide strong evidence of disruptions in MU firing behavior in paretic muscles after a hemispheric stroke, suggesting that modified control of the spinal motoneuron pool could be a contributing factor to muscular weakness in stroke survivors.

  1. Incremental Mining for Regular Frequent Patterns in Vertical Format

    Directory of Open Access Journals (Sweden)

    Vijay Kumar G

    2013-04-01

    Full Text Available In the real world database updates continuously in several online applications like super market, network monitoring, web administration, stock market etc. Frequent pattern mining is afundamental and essential area in data mining research. Not only occurrence frequency of a pattern but also occurrence behaviour of a pattern may be treated as important criteria to measure the interestingness of a pattern. A frequent pattern is said to be regular frequent if the occurrence behaviour is less than or equal to the user given regularity threshold. In incremental transactional databases the occurrence frequency and the occurrence behaviour of a pattern changes whenever a small set of new transactions are added to the database. It is undesirable to mine regular frequent patterns from the scratch. Thus proposes a new algorithm called RFPID (Regular Frequent Pattern Mining in Incremental Databases to mine regular frequent patterns in incremental transactional databases using vertical data format which requires only one database scan. The experimental results show our algorithm is efficient in both memory utilization and execution.

  2. Micron-scale pattern formation in prestressed polygonal films

    NARCIS (Netherlands)

    Annabattula, R. K.; Onck, P. R.

    2011-01-01

    In this paper we explore the spontaneous formation of micropatterns in thin prestressed polygonal films using finite element simulations. We study films with different size, thickness, and shape, including square, rectangular, pentagonal, and hexagonal films. Patterns form when the films release the

  3. Self-organized surface ripple pattern formation by ion implantation

    Science.gov (United States)

    Hofsäss, Hans; Zhang, Kun; Bobes, Omar

    2016-10-01

    Ion induced ripple pattern formation on solid surfaces has been extensively studied in the past and the theories describing curvature dependent ion erosion as well as redistribution of recoil atoms have been very successful in explaining many features of the pattern formation. Since most experimental studies use noble gas ion irradiation, the incorporation of the ions into the films is usually neglected. In this work we show that the incorporation or implantation of non-volatile ions also leads to a curvature dependent term in the equation of motion of a surface height profile. The implantation of ions can be interpreted as a negative sputter yield; and therefore, the effect of ion implantation is opposite to the one of ion erosion. For angles up to about 50°, implantation of ions stabilizes the surface, whereas above 50°, ion implantation contributes to the destabilization of the surface. We present simulations of the curvature coefficients using the crater function formalism and we compare the simulation results to the experimental data on the ion induced pattern formation using non-volatile ions. We present several model cases, where the incorporation of ions is a crucial requirement for the pattern formation.

  4. Effects of muscle pain induced by glutamate injections during sustained clenching on the contraction pattern of masticatory muscles.

    Science.gov (United States)

    Michelotti, Ambrosina; Cioffi, Iacopo; Rongo, Roberto; Borrelli, Roberta; Chiodini, Paolo; Svensson, Peter

    2014-01-01

    To evaluate the contraction pattern of masticatory muscles during sustained clenching tasks with or without experimental pain induced by glutamate injection into the masseter muscle. It was hypothesized that acute muscle pain could induce compensatory changes in the electromyographic (EMG) activity of the masticatory muscles. Fifteen volunteers (seven males, mean age ± SD = 29.7 ± 1.1 years; eight females, mean age ± SD = 23.5 ± 1.2 years) were recruited in a crossover experimental study. All subjects participated in two randomized 20-minute experimental sessions. Each subject was asked to clench at 25% of the maximum voluntary contraction (MVC). After 10 minutes, isotonic saline or glutamate was injected in random order into the right masseter. EMG activity (root mean square [RMS] and mean power frequency [MPF]) was assessed in the masseter and anterior temporalis muscles on both sides. Pain and fatigue were assessed by 0-10 numeric rating scales (NRS) every minute. Differences between conditions (isotonic saline vs glutamate) for all the outcome parameters were analyzed by using a mixed effect model. The EMG activity of the masticatory muscles and pain and fatigue scores were not dependent on isotonic saline/glutamate injection (all P > .05). The RMS in the temporalis and masseter muscles increased with time (right masseter P = 0.001, left masseter P = .004, right temporalis P = .22, left temporalis P = .006), whereas the MPF decreased (right masseter P = .0001, left masseter P muscles during a sustained clenching task. This finding strongly suggests the adaptive capacity of the stomatognathic system in the presence of acute nociceptive inputs.

  5. Magnetization Transfer MR Imaging to Monitor Muscle Tissue Formation during Myogenic in Vivo Differentiation of Muscle Precursor Cells.

    Science.gov (United States)

    Rottmar, Markus; Haralampieva, Deana; Salemi, Souzan; Eberhardt, Christian; Wurnig, Moritz C; Boss, Andreas; Eberli, Daniel

    2016-11-01

    Purpose To determine whether magnetization transfer (MT) magnetic resonance (MR) imaging may serve as a quantitative measure of the degree of fiber formation during differentiation of muscle precursor cells into engineered muscle tissue as a potential noninvasive monitoring tool in mice. Materials and Methods The study was approved by the local ethics committee (no. StV 01/2008) and the local Veterinary Office (license no. 99/2013). Human muscle progenitor cells (hMPCs) derived from rectus abdominis muscles were subcutaneously injected into CD-1 nude mice (CD-1 nude mice, Crl:CD1-Foxn1(nu); Charles River Laboratories, Wilmington, Mass) for development of muscle tissue. The mice underwent MR imaging examinations at 4.7 T at days 1, 3, 7, 14, 21, and 28 after cell transplantation by using a gradient-echo sequence with an MT prepulse and systematic variation of the off-resonance frequency (50-37 500 Hz) at an amplitude of 800°. Direct saturation was estimated from a Bloch equation simulation. The MT ratio (MTR) was correlated to immunohistochemistry findings, Western blot results, and results of myography. Data were analyzed by using one-way or two-way analysis of variance with the Sidak or Tukey multiple comparisons test. Results In the reference skeletal muscle, highest MT was found for 2500 Hz off-resonance frequency with an MTR ± standard deviation of 57.5% ± 3.5. The developing muscle tissue exhibited increasing MT values during the 28 days of myogenic in vivo differentiation and did not reach the values of native skeletal muscle. Mean values of MTR (2500 Hz) for hMPCs were 27.6% ± 6.3 (day 1), 24.7% ± 8.7 (day 3), 28.2% ± 5.7 (day 7), 35.9% ± 5.0 (day 14), 37.0% ± 7.9 (day 21), and 39.9% ± 8.1 (day 28). The results from MT MR imaging correlated qualitatively well with muscle tissue expression of specific skeletal markers, as well as muscle contractility. Conclusion MT MR imaging may be used to noninvasively monitor the process of myogenic in vivo

  6. Flow Visualization and Pattern Formation in Vertically Falling Liquid Films

    Science.gov (United States)

    Balakotaiah, Vemuri; Malamataris, Nikolaos

    2008-11-01

    Analytical results of a low-dimensional two equation h-q model and results of a direct numerical simulation of the transient two-dimensional Navier Stokes equations are presented for vertically falling liquid films along a solid wall. The numerical study aims at the elucidation of the hydrodynamics of the falling film. The analytical study aims at the calculation of the parameter space where pattern formation occurs for this flow. It has been found that when the wave amplitude exceeds a certain magnitude, flow reversal occurs in the film underneath the minimum of the waves [1]. The instantaneous vortical structures possess two hyperbolic points on the vertical wall and an elliptic point in the film. As the wave amplitude increases further, the elliptic point reaches the free surface of the film and two more hyperbolic points are formed in the free surface that replace the elliptic point. Between the two hyperbolic points on the free surface, the streamwise component of velocity is negative and the film is divided into asymmetric patterns of up and down flows. Depending on the value of the Kapitza number, these patterns are either stationary or oscillatory. Physical reasons for the influence of the Kapitza number on pattern formation are given. Movies are shown where the pattern formation is demonstrated. [1] N.A.Malamataris and V.Balakotaiah (2008), AIChE J., 54(7), p. 1725-1740

  7. Regenerating sprouts of axotomized cat muscle afferents express characteristic firing patterns to mechanical stimulation.

    Science.gov (United States)

    Johnson, R D; Munson, J B

    1991-12-01

    1. In cats, we studied the physiological properties of regenerating sprouts of muscle afferent fibers and compared them with sprouts from cutaneous afferent fibers. 2. Muscle nerves to the triceps surae and cutaneous sural nerves were axotomized in the popliteal fossa, and the proximal ends were inserted into nerve cuffs. Six days later, we recorded action potentials from single Groups I and II muscle and mostly Group II cutaneous afferents driven by mechanostimulation of the cuff. 3. Most muscle afferent sprouts (91%) had a regular slowly adapting discharge in response to sustained mechanical displacement of the cuff, particularly to sustained stretch stimuli, whereas most cutaneous afferents (92%) did not. Muscle afferents were more likely to have a spontaneous discharge and afterdischarge. 4. Group II muscle afferent sprouts had lower stretch thresholds and a higher incidence of spontaneous discharge compared with Group I fiber sprouts, whereas Group I fibers had a higher incidence of high-frequency afterdischarge to mechanical stimuli. 5. We conclude that, 6 days after axotomy, regenerating sprouts of muscle afferents, particularly Group II afferents, have become mechanosensitive in the absence of a receptor target and exhibit physiological properties similar to those found when innervating their native muscle but significantly different from sprouts of cutaneous afferents. Expression of these native muscle afferent firing patterns after the inappropriate reinnervation of hairy skin may be due to inherent properties of the muscle afferent fiber.

  8. Spontaneous pattern formation in broad-area lasers

    Science.gov (United States)

    Krents, Anton; Anchikov, Dmitry; Molevich, Nonna; Pakhomov, Anton

    2016-10-01

    The paper studies the spontaneous formation of nonlinear optical patterns in broad area lasers. Spatiotemporal transverse dynamics of the laser is described by the Maxwell-Bloch equations (MBE). The instability of the steady-state solution leads to pattern formation. Two different types of instabilities were observed analytically (Hopf and wave). 2D numerical simulation of the MBE with the random initial conditions has been performed using a split-step Fourier method and periodic boundary conditions. Hopf instability leads to homogeneous oscillations, spatiotemporal chaos and spiral waves. In the case of wave instability, the direct numerical simulation showed that space-time (periodic, quasi-periodic, or chaotic) modulation of the uniform profile is observed. The characteristic sizes of excited patterns are in good agreement with analytical predictions. The nonlinear interaction of four travelling waves forms a square optical vortex lattice similar to the vortex lattices observed in superconductors and Bose Einstein condensate.

  9. Dewetting-mediated pattern formation inside the coffee ring

    Science.gov (United States)

    Li, Weibin; Lan, Ding; Wang, Yuren

    2017-04-01

    The rearrangement of particles in the final stage of droplet evaporation has been investigated by utilizing differential interference contrast microscopy and the formation mechanism of a network pattern inside a coffee ring has been revealed. A tailored substrate with a circular hydrophilic domain is prepared to obtain thin liquid film containing monolayer particles. Real-time bottom-view images show that the evolution of a dry patch could be divided into three stages: rupture initiation, dry patch expansion, and drying of the residual liquid. A growing number of dry patches will repeat these stages to form the network patterns inside the ringlike stain. It can be shown that the suction effect promotes the rupture of the liquid film and the formation of the dry patch. The particle-assembling process is totally controlled by the liquid film dewetting and dominated by the surface tension of the liquid film, which eventually determine the ultimate deposition patterns.

  10. Noise induced pattern formation of oscillation growth in traffic flow

    CERN Document Server

    Tian, Junfang; Treiber, Martin

    2016-01-01

    Noise is able to induce diverse patterns in physical and interdisciplinary extended systems. This Letter investigates the role of noise in pattern formation of traffic flow, which is a typical self-driven system far from equilibrium. We demonstrate that noise is necessary to correctly describe the observed spatiotemporal dynamics of growing traffic oscillation in the car following process. A heuristic analysis qualitatively explains the concave growth of the oscillation amplitude along the vehicles of a platoon. Based on this analysis, we propose a simple car-following model containing indifference regions and acceleration noise described by Brownian motion which reproduces well the experimental and empirical observations. Our study indicates that noise might also play an important role in pattern formation in other biological or socio-economic systems that are subject to stochasticity.

  11. Pattern formation in oscillatory complex networks consisting of excitable nodes

    Science.gov (United States)

    Liao, Xuhong; Xia, Qinzhi; Qian, Yu; Zhang, Lisheng; Hu, Gang; Mi, Yuanyuan

    2011-05-01

    Oscillatory dynamics of complex networks has recently attracted great attention. In this paper we study pattern formation in oscillatory complex networks consisting of excitable nodes. We find that there exist a few center nodes and small skeletons for most oscillations. Complicated and seemingly random oscillatory patterns can be viewed as well-organized target waves propagating from center nodes along the shortest paths, and the shortest loops passing through both the center nodes and their driver nodes play the role of oscillation sources. Analyzing simple skeletons we are able to understand and predict various essential properties of the oscillations and effectively modulate the oscillations. These methods and results will give insights into pattern formation in complex networks and provide suggestive ideas for studying and controlling oscillations in neural networks.

  12. Role of Ryanodine Receptor Subtypes in Initiation and Formation of Calcium Sparks in Arterial Smooth Muscle: Comparison with Striated Muscle

    Directory of Open Access Journals (Sweden)

    Maik Gollasch

    2009-01-01

    Full Text Available Calcium sparks represent local, rapid, and transient calcium release events from a cluster of ryanodine receptors (RyRs in the sarcoplasmic reticulum. In arterial smooth muscle cells (SMCs, calcium sparks activate calcium-dependent potassium channels causing decrease in the global intracellular [Ca2+] and oppose vasoconstriction. This is in contrast to cardiac and skeletal muscle, where spatial and temporal summation of calcium sparks leads to global increases in intracellular [Ca2+] and myocyte contraction. We summarize the present data on local RyR calcium signaling in arterial SMCs in comparison to striated muscle and muscle-specific differences in coupling between L-type calcium channels and RyRs. Accordingly, arterial SMC Cav1.2 L-type channels regulate intracellular calcium stores content, which in turn modulates calcium efflux though RyRs. Downregulation of RyR2 up to a certain degree is compensated by increased SR calcium content to normalize calcium sparks. This indirect coupling between Cav1.2 and RyR in arterial SMCs is opposite to striated muscle, where triggering of calcium sparks is controlled by rapid and direct cross-talk between Cav1.1/Cav1.2 L-type channels and RyRs. We discuss the role of RyR isoforms in initiation and formation of calcium sparks in SMCs and their possible molecular binding partners and regulators, which differ compared to striated muscle.

  13. Interstitial and plasma adenosine stimulate nitric oxide and prostacyclin formation in human skeletal muscle

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Thaning, Pia;

    2010-01-01

    One major unresolved issue in muscle blood flow regulation is that of the role of circulating versus interstitial vasodilatory compounds. The present study determined adenosine-induced formation of NO and prostacyclin in the human muscle interstitium versus in femoral venous plasma to elucidate....... In young healthy humans, microdialysate was collected at rest, during arterial infusion of adenosine, and during interstitial infusion of adenosine through microdialysis probes inserted into musculus vastus lateralis. Muscle interstitial NO and prostacyclin increased with arterial and interstitial infusion...... levels. These findings provide novel insight into the role of adenosine in skeletal muscle blood flow regulation and vascular function by revealing that both interstitial and plasma adenosine have a stimulatory effect on NO and prostacyclin formation. In addition, both skeletal muscle and microvascular...

  14. Shoulder muscle recruitment patterns during a kayak stroke performed on a paddling ergometer.

    Science.gov (United States)

    Trevithick, Beverley A; Ginn, Karen A; Halaki, Mark; Balnave, Ronald

    2007-02-01

    Precise muscle co-ordination is required to maintain normal shoulder function and alterations in synchrony between shoulder muscles can result in loss of full range of movement and pain. Although shoulder pain in kayakers is high with 53% of elite international paddlers reporting shoulder injuries, little information is available regarding the pattern of shoulder muscle recruitment during paddling. The aim of this study was to investigate the normal recruitment pattern of shoulder muscles during the kayak stroke. Nine recreational paddlers without shoulder pain were examined. EMG data from eight shoulder muscles of the dominant arm were collected simultaneously with video data during simulated paddling on an ergometer. EMG data was normalized to time and peak amplitude. Intersubject consistency was evaluated using Pearson correlation analysis. The results of this study indicated a fair to high correlation in at least one phase of the kayak stroke in five of the muscles examined: upper trapezius, supraspinatus, latissimus dorsi, serratus anterior and rhomboid major. This normative data will enable comparisons with the shoulder muscle recruitment patterns in kayakers with shoulder pain in order to determine the role of altered motor control in the painful kayaking shoulder.

  15. The influence of specific training on trunk muscle recruitment patterns in healthy subjects during stabilization exercises.

    Science.gov (United States)

    Stevens, Veerle K; Coorevits, Pascal L; Bouche, Katie G; Mahieu, Nele N; Vanderstraeten, Guy G; Danneels, Lieven A

    2007-08-01

    Low back pain is a major problem involving high medical costs, therefore effective prevention strategies are essential. Stabilization exercises seem to facilitate the neuromuscular control of the lumbar spine and may be useful in prevention programs. To investigate whether specific lumbar stabilization training has an effect on muscle recruitment patterns in a healthy population, in the present study 30 subjects were recruited to perform two types of testing exercises, i.e. bridging exercises and exercises in four-point kneeling, both before and after training. Surface electromyographic data of different abdominal and back muscles were obtained. After training, analysis of the relative muscle activity levels (percentage of maximal voluntary isometric contraction) showed a higher activity of the local (segmental-stabilizing) abdominal muscles, but not of the local back muscles; minimal changes in global (torque-producing) muscle activity also occurred. Analysis of the local/global relative muscle activity ratios revealed higher ratios during all exercises after training, although not all differences were significant. These results indicate that muscle recruitment patterns can be changed in healthy subjects by means of a training program that focuses on neuromuscular control. Additional studies are needed to evaluate this type of training as a prevention strategy.

  16. The rotator cuff muscles have a direction specific recruitment pattern during shoulder flexion and extension exercises.

    Science.gov (United States)

    Wattanaprakornkul, Duangjai; Cathers, Ian; Halaki, Mark; Ginn, Karen A

    2011-09-01

    A recent study has shown that posterior rotator cuff (RC) muscles are recruited at significantly higher levels than the anterior RC during shoulder flexion. It was proposed that the mechanism whereby the posterior RC muscles were providing shoulder stability during flexion was to counterbalance potential anterior humeral head translation caused by flexion torque producing muscles. This hypothesis implies that anterior RC activity should be higher than posterior RC activity during extension to prevent posterior humeral head translation. As the normal recruitment pattern of the RC during extension has not been established, the purpose of this study was to examine this hypothesis by comparing shoulder muscle activation levels and recruitment patterns during flexion and extension exercises. Electromyographic (EMG) activity was recorded from 9 shoulder muscles in 15 volunteers. Flexion and extension exercises were performed in prone at 20%, 50%, and 70% of each participant's maximal load. A repeated measures ANOVA was used to determine differences between exercises, muscles and loads, while Pearson's correlation analysis was used to relate mean EMG patterns. During extension subscapularis and latissimus dorsi were activated at higher levels than during flexion; during flexion, supraspinatus, infraspinatus, deltoid, trapezius, and serratus anterior were more highly activated than during extension. In addition, the pattern of activity in each muscle did not vary with load. These results support the hypothesis that during flexion and extension the RC muscles are recruited in a direction specific manner to prevent potential antero-posterior humeral head translation caused by torque producing muscles. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  17. Liesegang patterns: Complex formation of precipitate in an electric field

    Indian Academy of Sciences (India)

    István Lagzi

    2005-02-01

    Formation of 1D Liesegang patterns was studied numerically in precipitation and reversible complex formation of precipitate scenarios in an electric field. The Ostwald’s supersaturation model reported by Büki, Kárpáti-Smidróczki and Zrínyi (BKZ model) was extended further. In the presence of an electric field the position of the first and the last bands () measured from the junction point of the outer and the inner electrolytes can be described by the function = 1 $_{}^{1/2}$ + 2 + 3 , where is the time elapsed until the nth band formation, 1, 2 and 3 are constants. The variation of the total number of bands with different electric field strengths () has a maximum. For higher one can observe a moving precipitation zone that becomes wider due to precipitation and reversible complex formation.

  18. A new mechanism for dendritic pattern formation in dense systems

    Science.gov (United States)

    Oikawa, Noriko; Kurita, Rei

    2016-06-01

    Patterns are often formed when particles cluster: Since patterns reflect the connectivity of different types of material, the emergence of patterns affects the physical and chemical properties of systems and shares a close relationship to their macroscopic functions. A radial dendritic pattern (RDP) is observed in many systems such as snow crystals, polymer crystals and biological systems. Although most of these systems are considered as dense particle suspensions, the mechanism of RDP formation in dense particle systems is not yet understood. It should be noted that the diffusion limited aggregation model is not applicable to RDP formation in dense systems, but in dilute particle systems. Here, we propose a simple model that exhibits RDP formation in a dense particle system. The model potential for the inter-particle interaction is composed of two parts, a repulsive and an attractive force. The repulsive force is applied to all the particles all the time and the attractive force is exerted only among particles inside a circular domain, which expands at a certain speed as a wave front propagating from a preselected centre. It is found that an RDP is formed if the velocity of the wave front that triggers the attractive interaction is of the same order of magnitude as the time scale defined by the aggregation speed.

  19. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

    Directory of Open Access Journals (Sweden)

    Alves-Pinto A

    2016-06-01

    Full Text Available Ana Alves-Pinto,1,* Tobias Blumenstein,1,* Varvara Turova,1 Renée Lampe1,2 1Research Unit of the Buhl-Strohmaier Foundation for Cerebral Palsy and Paediatric Neuroorthopaedics, Orthopaedic Department, Klinikum rechts der Isar, 2Markus Würth Professorship, Technical University of Munich, Munich, Germany *These authors contributed equally to this work Objective: Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP. However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility.Methods: Electromyographic (EMG recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions.Results: Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation

  20. Wavenumber Locking And Pattern Formation In Spatially Forced Systems

    Energy Technology Data Exchange (ETDEWEB)

    Hagberg, Aric [Los Alamos National Laboratory; Meron, Ehud [BEN-GURION UNIV; Manor, Rotem [BEN-GURION UNIV

    2008-01-01

    We study wavenumber locking and pattern formation resulting from weak spatially periodic one-dimensional forcing of two-dimensional systems. We consider systems that support stationary or traveling stripe patterns in the absence of the forcing, and assume that the one-dimensional forcing is aligned with the direction of the stripe patterns. When the forcing wavenumber is about twice as large as the wavenumber of the unforced system we find that the forcing can either select or stabilize a resonant stripe solution at half the forcing wavenumber, or create a new resonant solution. When the wavenumber mismatch is high we find that the wave-vector component of the pattern in the direction of the forcing can stilI lock at half the forcing wavenumber, but a wave-vector component in the orthogonal direction develops to compensate for the total wavenumber. As a result stationary two-dimensional rectangular and oblique patterns form. When the unforced system supports traveling waves resonant rectangular patterns remain stationary but the oblique patterns travel in a direction orthogonal to the traveling-waves.

  1. Perspective: network-guided pattern formation of neural dynamics.

    Science.gov (United States)

    Hütt, Marc-Thorsten; Kaiser, Marcus; Hilgetag, Claus C

    2014-10-05

    The understanding of neural activity patterns is fundamentally linked to an understanding of how the brain's network architecture shapes dynamical processes. Established approaches rely mostly on deviations of a given network from certain classes of random graphs. Hypotheses about the supposed role of prominent topological features (for instance, the roles of modularity, network motifs or hierarchical network organization) are derived from these deviations. An alternative strategy could be to study deviations of network architectures from regular graphs (rings and lattices) and consider the implications of such deviations for self-organized dynamic patterns on the network. Following this strategy, we draw on the theory of spatio-temporal pattern formation and propose a novel perspective for analysing dynamics on networks, by evaluating how the self-organized dynamics are confined by network architecture to a small set of permissible collective states. In particular, we discuss the role of prominent topological features of brain connectivity, such as hubs, modules and hierarchy, in shaping activity patterns. We illustrate the notion of network-guided pattern formation with numerical simulations and outline how it can facilitate the understanding of neural dynamics. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Clustering and Pattern Formation in Chemorepulsive Active Colloids.

    Science.gov (United States)

    Liebchen, Benno; Marenduzzo, Davide; Pagonabarraga, Ignacio; Cates, Michael E

    2015-12-18

    We demonstrate that migration away from self-produced chemicals (chemorepulsion) generates a generic route to clustering and pattern formation among self-propelled colloids. The clustering instability can be caused either by anisotropic chemical production, or by a delayed orientational response to changes of the chemical environment. In each case, chemorepulsion creates clusters of a self-limiting area which grows linearly with self-propulsion speed. This agrees with recent observations of dynamic clusters in Janus colloids (albeit not yet known to be chemorepulsive). More generally, our results could inform design principles for the self-assembly of chemorepulsive synthetic swimmers and/or bacteria into nonequilibrium patterns.

  3. Boundary-layer model of pattern formation in solidification

    Science.gov (United States)

    Ben-Jacob, E.; Goldenfeld, N.; Langer, J. S.; Schon, G.

    1984-01-01

    A model of pattern formation in crystal growth is proposed, and its analytic properties are investigated. The principal dynamical variables in this model are the curvature of the solidification front and the thickness (or heat content) of a thermal boundary layer, both taken to be functions of position along the interface. This model is mathematically much more tractable than the realistic, fully nonlocal version of the free-boundary problem, and still recaptures many of the features that seem essential for studying dendritic behavior, for example. Preliminary numerical solutions produce snowflakelike patterns similar to those seen in nature.

  4. Differential activity patterns in the masseter muscle under simulated clenching and grinding forces.

    Science.gov (United States)

    Schindler, H J; Türp, J C; Blaser, R; Lenz, J

    2005-08-01

    The aim of this study was to investigate (i) whether the masseter muscle shows differential activation under experimental conditions which simulate force generation during clenching and grinding activities; and (ii) whether there are (a) preferentially active muscle regions or (b) force directions which show enhanced muscle activation. To answer these questions, the electromyographic (EMG) activity of the right masseter muscle was recorded with five intramuscular electrodes placed in two deep muscle areas and in three surface regions. Intraoral force transfer and force measurement were achieved by a central bearing pin device equipped with three strain gauges (SG). The activity distribution in the muscle was recorded in four different mandibular positions (central, left, right, anterior). In each position, maximum voluntary contraction (MVC) was exerted in vertical, posterior, anterior, medial and lateral directions. The investigated muscle regions showed different amount of EMG activity. The relative intensity of the activation, with respect to other regions, changed depending on the task. In other words, the muscle regions demonstrated heterogeneous changes of the EMG pattern for the various motor tasks. The resultant force vectors demonstrated similar amounts in all horizontal bite directions. Protrusive force directions revealed the highest relative activation of the masseter muscle. The posterior deep muscle region seemed to be the most active compartment during the different motor tasks. The results indicate a heterogeneous activation of the masseter muscle under test conditions simulating force generation during clenching and grinding. Protrusively directed bite forces were accompanied by the highest activation in the muscle, with the posterior deep region as the most active area.

  5. Morphogenesis and pattern formation in biological systems experiments and models

    CERN Document Server

    Noji, Sumihare; Ueno, Naoto; Maini, Philip

    2003-01-01

    A central goal of current biology is to decode the mechanisms that underlie the processes of morphogenesis and pattern formation. Concerned with the analysis of those phenomena, this book covers a broad range of research fields, including developmental biology, molecular biology, plant morphogenesis, ecology, epidemiology, medicine, paleontology, evolutionary biology, mathematical biology, and computational biology. In Morphogenesis and Pattern Formation in Biological Systems: Experiments and Models, experimental and theoretical aspects of biology are integrated for the construction and investigation of models of complex processes. This collection of articles on the latest advances by leading researchers not only brings together work from a wide spectrum of disciplines, but also provides a stepping-stone to the creation of new areas of discovery.

  6. Femtosecond Laser Patterning of the Biopolymer Chitosan for Biofilm Formation

    Science.gov (United States)

    Estevam-Alves, Regina; Ferreira, Paulo Henrique Dias; Coatrini, Andrey C.; Oliveira, Osvaldo N.; Fontana, Carla Raquel; Mendonca, Cleber Renato

    2016-01-01

    Controlling microbial growth is crucial for many biomedical, pharmaceutical and food industry applications. In this paper, we used a femtosecond laser to microstructure the surface of chitosan, a biocompatible polymer that has been explored for applications ranging from antimicrobial action to drug delivery. The influence of energy density on the features produced on chitosan was investigated by optical and atomic force microscopies. An increase in the hydrophilic character of the chitosan surface was attained upon laser micromachining. Patterned chitosan films were used to observe Staphylococcus aureus (ATCC 25923) biofilm formation, revealing an increase in the biofilm formation in the structured regions. Our results indicate that fs-laser micromachining is an attractive option to pattern biocompatible surfaces, and to investigate basic aspects of the relationship between surface topography and bacterial adhesion. PMID:27548153

  7. Pattern formation and coexistence domains for a nonlocal population dynamics

    CERN Document Server

    da Cunha, J A R; Oliveira, F A

    2011-01-01

    In this communication we propose a most general equation to study pattern formation for one-species population and their limit domains in systems of length L. To accomplish this we include non-locality in the growth and competition terms where the integral kernels are now depend on characteristic length parameters alpha and beta. Therefore, we derived a parameter space (alpha,beta) where it is possible to analyze a coexistence curve alpha*=alpha*(\\beta) which delimits domains for the existence (or not) of pattern formation in population dynamics systems. We show that this curve has an analogy with coexistence curve in classical thermodynamics and critical phenomena physics. We have successfully compared this model with experimental data for diffusion of Escherichia coli populations.

  8. Closing the Loop: Integrating Body, Muscle and Environment with Locomotion Central Pattern Generators

    Science.gov (United States)

    2013-06-30

    simple closed-loop model in which a CPG produces a pattern of muscle activation which is modified by sensory feedback related to body curvature . (a...by a complex interaction of the neural circuits in the spinal cord and brain, the body, the muscles, sensory organs and the environment. With- out...feedback related to body curvature . 2.1 Computation of optimal feedback for the control of locomotion We have a developed a general method of computing

  9. Correlation between facial patterns and function of the masticatory muscles in girls and women.

    Science.gov (United States)

    Nakakawaji, Kenji; Kodachi, Kenji; Sakamoto, Teruo; Harazaki, Morihiro; Isshiki, Yasushige

    2002-05-01

    The relationship between maxillo-facial patterns and function of the masticatory muscles was evaluated using electromyography, in 16 women with functional normal occlusion and 16 girls with chronological normal occlusion half of them had the dolico facial pattern and the others had the brachyo facial pattern by Ricketts analysis. For the electromyography, loads of 1, 2, 3, 4, and 5 kg were applied to the mandible, and muscular activity waves were obtained from the masseter muscle and the anterior belly of the temporal muscle during isometric contraction by surface electrode induction. The median frequency value (MFV) in a frequency curve obtained by high-speed Fourier transform of the electromyographic waves was set to the evaluation index. The MFV at each applied load was higher in the adult brachyo facial pattern group than in the adult dolico facial pattern group in both the masseter and temporal muscles, whereas the differences in the MFV were slight in the child group at a 5% significance level. The child group showed approximately half the incidence of significant correlation coefficients in comparison with the adult group and a large standard deviation without marked differences in the facial patterns due to their individual differences in growth with a 5% significant level. The adult brachyo facial pattern group showed a high regression coefficient of the MFV in the masseter muscle according to the increase in the amount of the applied load. Although differences in the cooperative contraction patterns similar to those in the adult group were observed in both the child dolico and brachyo facial pattern groups, no marked significant differences were observed in the child group, who had large individual differences due to their immature growth.

  10. Is interindividual variability of EMG patterns in trained cyclists related to different muscle synergies?

    Science.gov (United States)

    Hug, François; Turpin, Nicolas A; Guével, Arnaud; Dorel, Sylvain

    2010-06-01

    Our aim was to determine whether muscle synergies are similar across trained cyclists (and thus whether the same locomotor strategies for pedaling are used), despite interindividual variability of individual EMG patterns. Nine trained cyclists were tested during a constant-load pedaling exercise performed at 80% of maximal power. Surface EMG signals were measured in 10 lower limb muscles. A decomposition algorithm (nonnegative matrix factorization) was applied to a set of 40 consecutive pedaling cycles to differentiate muscle synergies. We selected the least number of synergies that provided 90% of the variance accounted for VAF. Using this criterion, three synergies were identified for all of the subjects, accounting for 93.5+/-2.0% of total VAF, with VAF for individual muscles ranging from 89.9+/-8.2% to 96.6+/-1.3%. Each of these synergies was quite similar across all subjects, with a high mean correlation coefficient for synergy activation coefficients (0.927+/-0.070, 0.930+/-0.052, and 0.877+/-0.110 for synergies 1-3, respectively) and muscle synergy vectors (0.873+/-0.120, 0.948+/-0.274, and 0.885+/-0.129 for synergies 1-3, respectively). Despite a large consistency across subjects in the weighting of several monoarticular muscles into muscle synergy vectors, we found larger interindividual variability for another monoarticular muscle (soleus) and for biarticular muscles (rectus femoris, gastrocnemius lateralis, biceps femoris, and semimembranosus). This study demonstrated that pedaling is accomplished by the combination of the similar three muscle synergies among trained cyclists. The interindividual variability of EMG patterns observed during pedaling does not represent differences in the locomotor strategy for pedaling.

  11. Modelling Global Pattern Formations for Collaborative Learning Environments

    DEFF Research Database (Denmark)

    Grappiolo, Corrado; Cheong, Yun-Gyung; Khaled, Rilla;

    2012-01-01

    We present our research towards the design of a computational framework capable of modelling the formation and evolution of global patterns (i.e. group structures) in a population of social individuals. The framework is intended to be used in collaborative environments, e.g. social serious games...... and computer simulations of artificial societies. The theoretical basis of our research, together with current state of the art and future work, are briefly introduced....

  12. On pattern formation in the Gray-Scott model

    Institute of Scientific and Technical Information of China (English)

    Rui PENG; Ming-xin WANG

    2007-01-01

    In the paper, we investigate an elliptic system well-known as the Gray-Scott model and present some further results for positive solutions of this model. More precisely, we give the refined a priori estimates of positive solutions, and improve some previous results for the non-existence and existence of positive non-constant solutions as the parameters are varied, which imply some certain conditions where the pattern formation occurs or not.

  13. The muscle activation patterns of lower limb during stair climbing at different backpack load.

    Science.gov (United States)

    Yali, Han; Aiguo, Song; Haitao, Gao; Songqing, Zhu

    2015-01-01

    Stair climbing under backpack load condition is a challenging task. Understanding muscle activation patterns of lower limb during stair climbing with load furthers our understanding of the factors involved in joint pathology and the effects of treatment. At the same time, stair climbing under backpack load requires adjustments of muscle activations and increases joint moment compared to level walking, which with muscle activation patterns are altered as a result of using an assistive technology, such as a wearable exoskeleton leg for human walking power augmentation. Therefore, the aim of this study was to analyze lower limb muscles during stair climbing under different backpack load. Nine healthy volunteers ascended a four-step staircase at different backpack load (0 kg, 10 kg, 20 kg, 30 kg). Electromyographic (EMG) signals were recorded from four lower limb muscles (gastrocnemius, tibialis anterior, hamstring, rectus femoris). The results showed that muscle activation amplitudes of lower limb increase with increasing load during stair climbing, the maximum RMS of gastrocnemius are greater than tibialis anterior, hamstring and rectus femoris whether stair climbing or level walking under the same load condition. However, the maximum RMS of hamstring are smaller than gastrocnemius, tibialis anterior and rectus femoris. The study of muscle activation under different backpack load during stair climbing can be used to design biomechanism and explore intelligent control based on EMG for a wearable exoskeleton leg for human walking power augmentation.

  14. Effect of cadence regulation on muscle activation patterns during robot assisted gait: a dynamic simulation study.

    Science.gov (United States)

    Hussain, Shahid; Xie, Sheng Q; Jamwal, Prashant K

    2013-03-01

    Cadence or stride frequency is an important parameter being controlled in gait training of neurologically impaired subjects. The aim of this study was to examine the effects of cadence variation on muscle activation patterns during robot assisted unimpaired gait using dynamic simulations. A twodimensional (2-D) musculoskeletal model of human gait was developed considering eight major muscle groups along with existing ground contact force (GCF) model. A 2-D model of a robotic orthosis was also developed which provides actuation to the hip, knee and ankle joints in the sagittal plane to guide subjects limbs on reference trajectories. A custom inverse dynamics algorithm was used along with a quadratic minimization algorithm to obtain a feasible set of muscle activation patterns. Predicted patterns of muscle activations during slow, natural and fast cadence were compared and the mean muscle activations were found to be increasing with an increase in cadence. The proposed dynamic simulation provide important insight into the muscle activation variations with change in cadence during robot assisted gait and provide the basis for investigating the influence of cadence regulation on neuromuscular parameters of interest during robot assisted gait.

  15. An Analysis of Intrinsic and Extrinsic Hand Muscle EMG for Improved Pattern Recognition Control.

    Science.gov (United States)

    Adewuyi, Adenike A; Hargrove, Levi J; Kuiken, Todd A

    2016-04-01

    Pattern recognition control combined with surface electromyography (EMG) from the extrinsic hand muscles has shown great promise for control of multiple prosthetic functions for transradial amputees. There is, however, a need to adapt this control method when implemented for partial-hand amputees, who possess both a functional wrist and information-rich residual intrinsic hand muscles. We demonstrate that combining EMG data from both intrinsic and extrinsic hand muscles to classify hand grasps and finger motions allows up to 19 classes of hand grasps and individual finger motions to be decoded, with an accuracy of 96% for non-amputees and 85% for partial-hand amputees. We evaluated real-time pattern recognition control of three hand motions in seven different wrist positions. We found that a system trained with both intrinsic and extrinsic muscle EMG data, collected while statically and dynamically varying wrist position increased completion rates from 73% to 96% for partial-hand amputees and from 88% to 100% for non-amputees when compared to a system trained with only extrinsic muscle EMG data collected in a neutral wrist position. Our study shows that incorporating intrinsic muscle EMG data and wrist motion can significantly improve the robustness of pattern recognition control for application to partial-hand prosthetic control.

  16. Capillary-mediated interface perturbations: Deterministic pattern formation

    Science.gov (United States)

    Glicksman, Martin E.

    2016-09-01

    Leibniz-Reynolds analysis identifies a 4th-order capillary-mediated energy field that is responsible for shape changes observed during melting, and for interface speed perturbations during crystal growth. Field-theoretic principles also show that capillary-mediated energy distributions cancel over large length scales, but modulate the interface shape on smaller mesoscopic scales. Speed perturbations reverse direction at specific locations where they initiate inflection and branching on unstable interfaces, thereby enhancing pattern complexity. Simulations of pattern formation by several independent groups of investigators using a variety of numerical techniques confirm that shape changes during both melting and growth initiate at locations predicted from interface field theory. Finally, limit cycles occur as an interface and its capillary energy field co-evolve, leading to synchronized branching. Synchronous perturbations produce classical dendritic structures, whereas asynchronous perturbations observed in isotropic and weakly anisotropic systems lead to chaotic-looking patterns that remain nevertheless deterministic.

  17. Langmuir films of chiral lipid molecules and Pattern Formation .

    Science.gov (United States)

    Basnet, Prem; Mann, Elizabeth; Chaieb, Sahraoui

    2009-03-01

    Langmuir films of 1,2-bis(10,12 Tricosadiynoyl)-sn-Glycero-3-Phosphoethanolamine form spiral and target patterns when compressed between two movable barriers in a Langmuir trough above 30^0C, up to the chain-melting transition at ˜37^0C. The critical pressure, at which spirals appear, increases with temperature. The patterns themselves also depend on temperature, with single-armed spirals with many defects forming near 30^0C and defect-free target patterns at higher temperatures. The mechanism of spiral formation could be a competition among elasticity, chirality, and the boundary conditions at the core of the domains. Optical anisotropy and the growth rate of internal structures test this suggested mechanism. .

  18. A Model of Filamentous Cyanobacteria Leading to Reticulate Pattern Formation

    Directory of Open Access Journals (Sweden)

    Carlos Tamulonis

    2014-09-01

    Full Text Available The filamentous cyanobacterium, Pseudanabaena, has been shown to produce reticulate patterns that are thought to be the result of its gliding motility. Similar fossilized structures found in the geological record constitute some of the earliest signs of life on Earth. It is difficult to tie these fossils, which are billions of years old, directly to the specific microorganisms that built them. Identifying the physicochemical conditions and microorganism properties that lead microbial mats to form macroscopic structures can lead to a better understanding of the conditions on Earth at the dawn of life. In this article, a cell-based model is used to simulate the formation of reticulate patterns in cultures of Pseudanabaena. A minimal system of long and flexible trichomes capable of gliding motility is shown to be sufficient to produce stable patterns consisting of a network of streams. Varying model parameters indicate that systems with little to no cohesion, high trichome density and persistent movement are conducive to reticulate pattern formation, in conformance with experimental observations.

  19. Pattern Formation and Secondary Instabilities for Convection in Porous Media

    Science.gov (United States)

    Behringer, R. P.; Fiering, J.

    1996-11-01

    In recent work(Howle et al. Nature 362), 230 (1993); JFM to appear we showed that the pattern formation for convection in porous media could be studied by means of a simple shadowgraph if there is a line of sight through the medium which does not encounter curved fluid-medium interfaces. This work focused primarily on pattern formation near onset and was carried out in relatively small aspect ratios, Γ (the ratio of the horizontal dimension of the layer to the height, d). We present new studies with both higher Γ, and at high enough Rayleigh number R to encounter the secondary instabilities for the convection roll patterns. In a Γ = radius/d = 10.7 cylindrical experiment with a medium made from stacked bars, we find well aligned convection rolls with wavelength, λ in good agreement with theory. The alignment direction is determined by the periodic structure of the medium. In two other experiments, also with bar stackings for the medium, we have studied the secondary instabilities. The experiments have Γ = 4 and 8, respectively (with square planform), and consist of 8 and 4 layers of bars. In both cases, the instability is to cross rolls. In the Γ = 8 case, the strong symmetry of the system leads to heteroclinic orbits between different patterns.

  20. An analysis of motor unit firing pattern during sustained low force contraction in fatigued muscle.

    Science.gov (United States)

    Olsen, H B; Christensen, H; Søgaard, K

    2001-01-01

    In the present study motor unit (MU) firing pattern was analysed during long-term static contraction in order to see if fatigue would induce rotation of activity between different MU. Surface as well as intramuscular EMG were obtained from ten subjects during a sustained hand lift for 5 minutes after performance of a 30% MVC fatiguing contraction of the extensor carpi radialis muscle. A newly developed decomposition program constituted a powerful tool to obtain detailed knowledge of long term activity pattern of MU during low force contractions. Although the muscle was highly fatigued the majority of MU showed a continuous firing pattern after recruitment and no clear incidences of rotation were found for any of the subjects. Therefore, long term, low force contractions, as performed during many occupational work tasks, may involve continuous activation of the low threshold MU and this could have mechanical as well as metabolic implications for these muscle fibers.

  1. Fluctuations and Pattern Formation in Fluids with Competing Interactions

    Science.gov (United States)

    Imperio, A.; Pini, D.; Reatto, L.

    2007-08-01

    One of the most interesting phenomena in the soft-matter realm consists in the spontaneous formation of super-molecular structures (microphases) in condition of thermodynamic equilibrium. A simple mechanism responsible for this self-organization or pattern formation is based on the competition between attractive and repulsive forces with different length scales in the microscopic potential, typically, a short-range attraction against a longer-range repulsion. We analyse this problem by simulations in 2D fluids. We find that, as the temperature is lowered, liquid-vapor phase separation is inhibited by the competition between attraction and repulsion, and replaced by a transition to non-homogeneous phases. The structure of the fluid shows well defined signatures of the presence of both intra- and inter-cluster correlations. Even when the competition between attraction and repulsion is not so strong as to cause microphase formation, it still induces large density fluctuations in a wide region of the temperature-density plane. In this large-fluctuation regime, pattern formation can be triggered by a weak external modulating field.

  2. How to build transcriptional network models of mammalian pattern formation.

    Directory of Open Access Journals (Sweden)

    Chrissa Kioussi

    Full Text Available BACKGROUND: Genetic regulatory networks of sequence specific transcription factors underlie pattern formation in multicellular organisms. Deciphering and representing the mammalian networks is a central problem in development, neurobiology, and regenerative medicine. Transcriptional networks specify intermingled embryonic cell populations during pattern formation in the vertebrate neural tube. Each embryonic population gives rise to a distinct type of adult neuron. The homeodomain transcription factor Lbx1 is expressed in five such populations and loss of Lbx1 leads to distinct respecifications in each of the five populations. METHODOLOGY/PRINCIPAL FINDINGS: We have purified normal and respecified pools of these five populations from embryos bearing one or two copies of the null Lbx1(GFP allele, respectively. Microarrays were used to show that expression levels of 8% of all transcription factor genes were altered in the respecified pool. These transcription factor genes constitute 20-30% of the active nodes of the transcriptional network that governs neural tube patterning. Half of the 141 regulated nodes were located in the top 150 clusters of ultraconserved non-coding regions. Generally, Lbx1 repressed genes that have expression patterns outside of the Lbx1-expressing domain and activated genes that have expression patterns inside the Lbx1-expressing domain. CONCLUSIONS/SIGNIFICANCE: Constraining epistasis analysis of Lbx1 to only those cells that normally express Lbx1 allowed unprecedented sensitivity in identifying Lbx1 network interactions and allowed the interactions to be assigned to a specific set of cell populations. We call this method ANCEA, or active node constrained epistasis analysis, and think that it will be generally useful in discovering and assigning network interactions to specific populations. We discuss how ANCEA, coupled with population partitioning analysis, can greatly facilitate the systematic dissection of

  3. Nonlinear dynamics of pattern formation and pattern recognition in the rabbit olfactory bulb

    Science.gov (United States)

    Baird, Bill

    1986-10-01

    A mathematical model of the process of pattern recognition in the first olfactory sensory cortex of the rabbit is presented. It explains the formation and alteration of spatial patterns in neural activity observed experimentally during classical Pavlovian conditioning. On each inspiration of the animal, a surge of receptor input enters the olfactory bulb. EEG activity recorded at the surface of the bulb undergoes a transition from a low amplitude background state of temporal disorder to coherent oscillation. There is a distinctive spatial pattern of rms amplitude in this oscillation which changes reliably to a second pattern during each successful recognition by the animal of a conditioned stimulus odor. When a new odor is paired as conditioned stimulus, these patterns are replaced by new patterns that stabilize as the animal adapts to the new environment. I will argue that a unification of the theories of pattern formation and associative memory is required to account for these observations. This is achieved in a model of the bulb as a discrete excitable medium with spatially inhomogeneous coupling expressed by a connection matrix. The theory of multiple Hopf bifurcations is employed to find coupled equations for the amplitudes of competing unstable oscillatory modes. These may be created in the system by proper coupling and selectively evoked by specific classes of inputs. This allows a view of limit cycle attractors as “stored” fixed points of a gradient vector field and thereby recovers the more familiar dynamical systems picture of associative memory.

  4. Learning new gait patterns: Exploratory muscle activity during motor learning is not predicted by motor modules.

    Science.gov (United States)

    Ranganathan, Rajiv; Krishnan, Chandramouli; Dhaher, Yasin Y; Rymer, William Z

    2016-03-21

    The motor module hypothesis in motor control proposes that the nervous system can simplify the problem of controlling a large number of muscles in human movement by grouping muscles into a smaller number of modules. Here, we tested one prediction of the modular organization hypothesis by examining whether there is preferential exploration along these motor modules during the learning of a new gait pattern. Healthy college-aged participants learned a new gait pattern which required increased hip and knee flexion during the swing phase while walking in a lower-extremity robot (Lokomat). The new gait pattern was displayed as a foot trajectory in the sagittal plane and participants attempted to match their foot trajectory to this template. We recorded EMG from 8 lower-extremity muscles and we extracted motor modules during both baseline walking and target-tracking using non-negative matrix factorization (NMF). Results showed increased trajectory variability in the first block of learning, indicating that participants were engaged in exploratory behavior. Critically, when we examined the muscle activity during this exploratory phase, we found that the composition of motor modules changed significantly within the first few strides of attempting the new gait pattern. The lack of persistence of the motor modules under even short time scales suggests that motor modules extracted during locomotion may be more indicative of correlated muscle activity induced by the task constraints of walking, rather than reflecting a modular control strategy.

  5. T-tubule biogenesis and triad formation in skeletal muscle and implication in human diseases

    Directory of Open Access Journals (Sweden)

    Al-Qusairi Lama

    2011-07-01

    Full Text Available Abstract In skeletal muscle, the excitation-contraction (EC coupling machinery mediates the translation of the action potential transmitted by the nerve into intracellular calcium release and muscle contraction. EC coupling requires a highly specialized membranous structure, the triad, composed of a central T-tubule surrounded by two terminal cisternae from the sarcoplasmic reticulum. While several proteins located on these structures have been identified, mechanisms governing T-tubule biogenesis and triad formation remain largely unknown. Here, we provide a description of triad structure and plasticity and review the role of proteins that have been linked to T-tubule biogenesis and triad formation and/or maintenance specifically in skeletal muscle: caveolin 3, amphiphysin 2, dysferlin, mitsugumins, junctophilins, myotubularin, ryanodine receptor, and dihydhropyridine Receptor. The importance of these proteins in triad biogenesis and subsequently in muscle contraction is sustained by studies on animal models and by the direct implication of most of these proteins in human myopathies.

  6. Variations of lumbrical muscle innervation patterns in the hand, focusing on the dual innervation of the third lumbrical muscle.

    Science.gov (United States)

    Hur, Mi-Sun

    2017-02-01

    This study was conducted to clarify the innervation patterns of the lumbrical muscles by identifying the origin of the nerve fascicles innervating these muscles. The lumbricals in the hand were investigated in 50 specimens of embalmed Korean adult cadavers. Dual innervation of the third lumbrical was most frequently observed in 64.0%. The third lumbrical was innervated by a branch arising from the median nerve (MN) distal to site at which the superficial branch of the ulnar nerve (sUN) joins the MN in 34%. When separating and tracing the nerve fascicles from the MN distal to the communicating branch from the sUN to MN, the fascicles contained parts of the MN and sUN in 18% and part of the MN in 16%. These results will be helpful for accurate diagnoses, surgical procedures, and electrophysiological examinations in lesions of the MN and ulnar nerve in the hand. Muscle Nerve, 2016 Muscle Nerve 55: 160-165, 2017. © 2016 Wiley Periodicals, Inc.

  7. Shoulder joint stress and the formation of muscle disbalances suffered by tennis players

    OpenAIRE

    Průšová, Martina

    2011-01-01

    Title: Shoulder joint stress and the formation of muscle disbalances suffered by tennis players. Goals: Finding the correct cooperation of selected muscles during the initial stage of tennis service and discuss their impact and medical effects on the shoulder joint. Method: Kinematic analysis using the Qualisys Motion System, Electromyography Results: The shoulder joint stabilizes during the initial stage of service. The m. supraspinatus has a big significance in this motion. Key words: tenni...

  8. Arm position influences the activation patterns of trunk muscles during trunk range-of-motion movements.

    Science.gov (United States)

    Siu, Aaron; Schinkel-Ivy, Alison; Drake, Janessa Dm

    2016-10-01

    To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions.

  9. X-ray diffraction pattern from the flight muscle of Toxorhynchites towadensis reveals the specific phylogenic position of mosquito among Diptera.

    Science.gov (United States)

    Iwamoto, Hiroyuki

    2015-01-01

    The Diptera are a group of insects with only a single pair of wings (forewings), and are considered monophyletic (originating from a common ancestor). The flight muscle in Diptera has features not observed in other insects, such as the long Pro-Ala-rich peptide associated with tropomyosin, not with troponin-I as in other insects, and the formation of a superlattice by myosin filaments analogous to that in vertebrate skeletal muscle. Here we describe X-ray diffraction patterns from the flight muscle of a mosquito, Toxorhynchites towadensis (Culicidae), belonging to a primitive group of Diptera. The diffraction pattern indicates that myosin filaments in the flight muscle of this species do not form a superlattice. X-ray diffraction also shows meridional reflections that are not observed in other dipterans, but are present in the patterns from bumblebee (Hymenoptera) flight muscle. These observations suggest that the superlattice structure evolved after the common ancestor of Diptera had diverged from other insects. The flight muscle of mosquito may retain primitive structural features that are shared by Hymenoptera.

  10. Activation patterns in forearm muscles during archery shooting.

    Science.gov (United States)

    Ertan, H; Kentel, B; Tümer, S T; Korkusuz, F

    2003-02-01

    A contraction and relaxation strategy with regard to forearm muscles during the release of the bowstring has often been observed during archery, but has not well been described. The purpose of this study was to analyze this strategy in archers with different levels of expertise; elite, beginner and non-archers. Electromyography (EMG) activity of the M. flexor digitorum superficialis and the M. extensor digitorum were recorded at a sampling frequency of 500 Hz, together with a pulse synchronized with the clicker snap, for twelve shots by each subject. Raw EMG records, 1-s before and after the clicker pulse, were rectified, integrated and normalized. The data was then averaged for successive shots of each subject and later for each group. All subjects including non-archers developed an active contraction of the M. extensor digitorum and a gradual relaxation of the M. flexor digitorum superficialis with the fall of the clicker. In elite archers release started about 100 ms after the fall of the clicker, whereas in beginners and non-archers release started after about 200 and 300 ms, respectively. Non-archers displayed a preparation phase involving extensive extensor activity before the release of the bowstring, which was not observed in elite and beginner archers. In conclusion, archers released the bowstring by active contraction of the forearm extensors, whereas a clear relaxation of the forearm flexors affecting the release movement was not observed.

  11. Electromyographical Comparison of Muscle Activation Patterns Across Three Commonly Performed Kettlebell Exercises.

    Science.gov (United States)

    Lyons, Brian C; Mayo, Jerry J; Tucker, W Steven; Wax, Ben; Hendrix, Russell C

    2017-09-01

    Lyons, BC, Mayo, JJ, Tucker, WS, Wax, B, and Hendrix, RC. Electromyographical comparison of muscle activation patterns across 3 commonly performed kettlebell exercises. J Strength Cond Res 31(9): 2363-2370, 2017-The purpose of this study was to compare the muscle activation patterns of 3 different kettlebell (KB) exercises using electromyography (EMG). Fourteen resistance-trained subjects completed a 1-arm swing (Swing), 1-arm swing style snatch (Snatch), and a 1-arm clean (Clean) using a self-selected 8 to 10 repetition maximum load for each exercise. Trial sessions consisted of subjects performing 5 repetitions of each KB exercise. Mean EMG was used to assess the muscle activation of the biceps brachii, anterior deltoid, posterior deltoid, erector spinae (ES), vastus lateralis (VL), biceps femoris, contralateral external oblique (EO), and gluteus maximus during each lift using surface electrodes. The mean EMG was normalized using maximal voluntary contractions obtained from manual muscle testing. Repeated-measures analysis of variance revealed a significant difference in the muscle activation patterns of the ES (Swing > Snatch), EO (Snatch, Clean > Swing), and VL (Swing > Clean) across the 3 KB exercises. We conclude that although the KB Swing, Snatch, and Clean are total body exercises, they place different demands on the ES, contralateral EO, and the VL. Therefore, KBs represent an authentic alternative for lifters, and the Swing, Snatch, and Clean are not redundant exercises.

  12. Segmental variations in the patterns of somatic muscles: what roles for Hox?

    Science.gov (United States)

    Enriquez, Jonathan; Vincent, Alain

    2010-01-01

    Textbook drawings of human anatomy illustrate the diversity of body muscles that are essential for coordinated movements. The genetic and molecular bases of this muscle diversity remain, however, largely unknown. The rather simple Drosophila larval musculature--every (hemi)-segment of the Drosophila larva contains about 30 different somatic muscles, each composed of a single multinucleate syncitial fibre--makes it an ideal model to study this process. Each muscle displays its own identity which can be described as its specific position and orientation with respect to the dorso-ventral (D/V) and antero-posterior (A/P) axes, size (number of nuclei), attachment sites to the epidermis and innervations. Muscle specification is a multi-step process. Each muscle is seeded by a founder cell (FC). FCs display the unique property of being able to undergo multiple rounds of fusion with fusion competent myoblasts (FCMs). The current view is that muscle identity reflects the expression by each FC of a specific combination of "identity" transcription factors (iTFs) (reviews by [4, 5]). The transcriptional identity is propagated from the FC to nuclei of FCM recruited by the growing myofibre during the fusion process. FCs are born from the asymmetric division of progenitor cells which are themselves selected by Notch (N)-mediated lateral inhibition from promuscular clusters (equivalence groups of cells) specified at fixed positions within the somatic mesoderm; see Fig.2). The abdominal (A) A2 to A7 segments of the Drosophila embryo present the same muscle pattern, the thoracic (T) T2-T3 and A1 segments show variations of this pattern and the first thoracic segment (T1) and the eighth abdominal segment (A8) present fewer and more diversified muscles. While it is has long been shown that this diversification of the muscle pattern is determined by the autonomous function of homeotic genes in the mesoderm, the step at which segment-specific information carried by Hox proteins is

  13. The role of auxin signaling in early embryo pattern formation.

    Science.gov (United States)

    Smit, Margot E; Weijers, Dolf

    2015-12-01

    Pattern formation of the early Arabidopsis embryo generates precursors to all major cell types, and is profoundly controlled by the signaling molecule auxin. Here we discuss recent milestones in our understanding of auxin-dependent embryo patterning. Auxin biosynthesis, transport and response mechanisms interact to generate local auxin accumulation in the early embryo. New auxin-dependent reporters help identifying these sites, while atomic structures of transcriptional response mediators help explain the diverse outputs of auxin signaling. Key auxin outputs are control of cell identity and cell division orientation, and progress has been made towards understanding the cellular basis of each. Importantly, a number of studies have combined computational modeling and experiments to analyze the developmental role, genetic circuitry and molecular mechanisms of auxin-dependent cell division control.

  14. Fractal pattern formation in metallic ink sessile droplets

    Science.gov (United States)

    Hadj-Achour, Miloud; Brutin, David

    2014-11-01

    We report a fingering instability that occurs during the spreading and evaporation of a nanosuspension droplet. The patterns has a fractal structure similar to those reported by N. Shahidzadeh-Bonn et al. (2008) for salt crystallisation, during evaporation of saturated Na2SO4 on a hydrophilic surface. The fingering instability has been widely studied for both Newtonian and non-Newtonian fluids. However, we describe for the first time that a fingering instability is observed for the spreading of a nanosuspension sessile droplet. We demonstrate that in certain cases, the contact line evolves through different spreading regimes according to J. De Coninck et al. (2001) with an enhancement in the evaporation rate due the formation of the fractal patterns.

  15. Pattern Formation by Electrostatic Self-Organization of Membrane Proteins

    Science.gov (United States)

    Boedec, G.; Jaeger, M.; Homble, F.; Leonetti, M.

    2012-07-01

    The electric activity of biological cells and organs such as heart for example is at the origin of various phenomena of pattern formation. The electric membrane potential appears as the order parameter to characterize these spatiotemporal dynamics. A kind of patterns is characterized by a stationary spatial modulation of membrane potential along the cell, breaking a symmetry of the system. They are associated to transcellular currents. A mechanism proposed in literature is based on the coupling of the electric current produced by membrane proteins and their electrophoretic mobilities. Beyond its classical linear stability analysis, the numerical and theoretical analysis of this model offers a variety of spatiotemporal dynamics. Firstly, the background in the modelization of electric phenomena is recalled. Secondly, the analysis is focused on two nonlinear dynamics.

  16. The theory of pattern formation on directed networks.

    Science.gov (United States)

    Asllani, Malbor; Challenger, Joseph D; Pavone, Francesco Saverio; Sacconi, Leonardo; Fanelli, Duccio

    2014-07-31

    Dynamical processes on networks have generated widespread interest in recent years. The theory of pattern formation in reaction-diffusion systems defined on symmetric networks has often been investigated, due to its applications in a wide range of disciplines. Here we extend the theory to the case of directed networks, which are found in a number of different fields, such as neuroscience, computer networks and traffic systems. Owing to the structure of the network Laplacian, the dispersion relation has both real and imaginary parts, at variance with the case for a symmetric, undirected network. The homogeneous fixed point can become unstable due to the topology of the network, resulting in a new class of instabilities, which cannot be induced on undirected graphs. Results from a linear stability analysis allow the instability region to be analytically traced. Numerical simulations show travelling waves, or quasi-stationary patterns, depending on the characteristics of the underlying graph.

  17. Fatty acid pattern of lipids in normal and dystrophic human muscle.

    Science.gov (United States)

    Kunze, D; Reichmann, G; Egger, E; Olthoff, D; Döhler, K

    1975-11-21

    The fatty acid distribution of the main lipid fractions: triglycerides (TG), phosphatidylcholine (PCh), phosphatidylethanolamine (PE), and sphingomyelin (Sph) of muscle from 6 patients with progressive muscular dystrophy (p.m.d.), Duchenne, 8 to 12 years old was estimated and compared with normal controls of different age. In view of the results of several authors about varied fatty acid distribution in immature muscle a third group comprising samples of neonatal muscle was studied. 1. The fatty acid pattern of the lipid fractions TG, Sph, and PE from muscle of patients with p.m.d. shows no important variation in comparison to normal controls. In contrast to this the fatty acid distribution in PCh is extremely varied: the percentage of 18:2 is decreased and corrrespondingly the content of 18:1 is increased. In view of the high percentage (nearly 10%) in which linoleic acid is substituted by oleic acid in PCh, effects on the plasma membrane are to be expected. 2. The fatty acid pattern in neonatal muscle shows in narly all positions of the fractions TG, Sph, PE, and PCh a different distribution from normal or dystrophic muscle. In view of the most important variation in dystrophic muscle it must be stated that generally 18:2 is decreased. This deficit was replaced by an increase of all other fatty acids (not only at a substitution by 18:1 as given in p.m.d.). Therefore the diminished content of linoleic acid in PCh of neonatal and dystrophic muscle cannot be interpreted as expression of a corresponding or similar lipid metabolism in both tissues. The results were seen as signs of significant qualitative alterations especially of PCh in p.m.d. They were discussed as proof of our thesis that the basic defect in p.m.d. concerns the specific acylation of PCh with linoleic acid.

  18. Flow-Induced Control of Pattern Formation in Chemical Systems

    Science.gov (United States)

    Berenstein, Igal; Beta, Carsten

    Since Alan Turing's seminal paper in 1952, the study of spatio-temporal patterns that arise in systems of reacting and diffusing components has grown into an immense and vibrant realm of scientific research. This field includes not only chemical systems but spans many areas of science as diverse as cell and developmental biology, ecology, geosciences, or semiconductor physics. For several decades research in this field has concentrated on the vast variety of patterns that can emerge in reaction-diffusion systems and on the underlying instabilities. In the 1990s, stimulated by the pioneering work of Ott, Grebogi and Yorke, control of pattern formation arose as a new topical focus and gradually developed into an entire new field of research. On the one hand, research interests concentrated on control and suppression of undesired dynamical states, in particular on control of chaos. On the other hand, the design and engineering of particular space-time patterns became a major focus in this field that motivates ongoing scientific effort until today...

  19. Building better oscillators using nonlinear dynamics and pattern formation

    Indian Academy of Sciences (India)

    M C Cross; Eyal Kenig; John-Mark A Allen

    2015-03-01

    Frequency and time references play an essential role in modern technology and in living systems. The precision of self-sustained oscillations is limited by the effects of noise, which becomes evermore important as the sizes of the devices become smaller. In this paper, we review our recent theoretical results on using nonlinear dynamics and pattern formation to reduce the effects of noise and improve the frequency precision of oscillators, with particular reference to ongoing experiments on oscillators based on nanomechanical resonators. We discuss using resonator nonlinearity, novel oscillator architectures and the synchronization of arrays of oscillators, to improve the frequency precision.

  20. Biochemical and histochemical changes in energy supply enzyme pattern of muscles of the rat during old age.

    Science.gov (United States)

    Bass, A; Gutmann, E; Hanzlíková, V

    1975-01-01

    Senile muscles of the rat (28-36 months) show loss of overall activity of glycolytic and aerobic enzymes. However, there is a differential loss and shift of enzyme activity pattern in the three types of muscles. The extensor digitorum longus (EDL) and diaphragm show a decrease of ratios of glycolytic to aerobic-oxidative enzymes. This shift to a more oxidative type of metabolism is not observed in the soleus muscle. Decrease of enzyme activities is least marked in the diaphragm muscle. Biochemical analysis shows a trend to levelling out of metabolic differences between the different muscle types. This trend of 'dedifferentiation' is most marked when comparing EDL and soleus, least marked when comparing EDL and diaphragm muscle. The histochemical analysis shows a shift from the original mixed to a more uniform pattern of muscle fibres in the EDL and soleus muscle; this levelling-out of differences between enzymatic activities of different muscle fibres is not observed in the diaphragm muscle. Preferential atrophy and loss of ATPase activity in II muscle fibres in the soleus muscle and the occurrence of 'type grouping' are further characteristic features of senile muscle change. The findings show general (i.e. loss of enzyme activities) and differential trends of biochemical and histochemical enzyme changes in different types of muscles.

  1. Upper trapezius muscle activation patterns in neck–shoulder pain patients and healthy controls

    NARCIS (Netherlands)

    Voerman, G.E.; Vollenbroek-Hutten, M.M.R.; Hermens, H.J.

    2007-01-01

    This study aimed at investigating whether patients with neck–shoulder complaints from different aetiologies (work-related musculo-skeletal disorders, WMSD; whiplash associated disorders, WAD) show comparable muscle activation patterns, characterised by higher activation and lower relaxation levels o

  2. The effect of walking aids on muscle activation patterns during walking in stroke patients

    NARCIS (Netherlands)

    Buurke, Jaap; Hermens, Hermanus J.; Erren-Wolters, C.V.; Nene, A.V.

    2005-01-01

    The purpose of this study was to investigate changes in muscle activation patterns with respect to timing and amplitude that occur when subjects with stroke walk with and without a walking aid. This knowledge could help therapists in deciding whether or not patients should use a cane or quad stick w

  3. Association between facial growth pattern and facial muscle activity: A prospective cross-sectional study.

    Science.gov (United States)

    Alabdullah, Mohannad; Saltaji, Humam; Abou-Hamed, Hussein; Youssef, Mohamed

    2015-06-01

    To evaluate the relationship between facial growth pattern and electromyography (EMG) of facial muscles: anterior temporalis, masseter, buccinators, orbicularis oris, mentalis and anterior digastric. The sample consisted of 77 subjects aged between 18-28 years (mean age 21.10±2.03), with dental Class I relationship, normal overjet and overbite, balanced facial profile, no signs of temporomandibular disorders, and no previous orthodontic treatment. Facial growth pattern was determined on the lateral cephalograms according to the Björk sum (sum of the N-S-Ar, S-Ar-Go, and Ar-Go-Me angles) dividing the sample into three groups: horizontal facial pattern group (24 subjects), normal facial pattern group (41 subjects), and vertical facial pattern group (12 subjects). The EMG of anterior temporalis, masseter, buccinator, orbicularis oris, mentalis and anterior digastric muscles were examined for each patient in the rest position and in functional positions (central maximum intercuspation, chewing on right side, chewing on left side and swallowing). Mean values and standard deviation of EMG were obtained and compared between the three groups. At rest, the EMG of the masseter, orbicularis oris and anterior digastric were higher in the vertical facial pattern group compared with the other two groups, with a moderate positive correlation between the EMG of these muscles and the Björk sum (Pmuscles (Pmuscle activity and facial growth pattern. The findings suggest that the activity of masticatory and perioral muscles could play a role in the direction of the facial growth. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

  4. Control of Histamine-Producing Bacteria and Histamine Formation in Fish Muscle by Trisodium Phosphate.

    Science.gov (United States)

    Bjornsdottir-Butler, Kristin; Green, David P; Bolton, Greg E; McClellan-Green, Patricia D

    2015-06-01

    Scombrotoxin fish poisoning remains the primary cause of seafood poisoning outbreaks despite preventive guidelines. The purpose of this study was to investigate the use of pH for the control of growth and histamine formation by histamine-producing bacteria in fish muscle. We examined pH effects on growth and histamine formation in tuna fish infusion broth and in inoculated tuna and mahi-mahi fish muscle. Histamine production was significantly less for all bacterial strains at pH 8.5 compared to pH 5.5 in tuna fish infusion broth with no significant difference in growth. Elevated pH due to phosphate treatment of fish muscle tissues significantly reduced histamine formation with no effect on the growth of histamine-producing bacteria. This study revealed that phosphate treatment of mahi-mahi and tuna fish muscle resulted in significantly lower histamine production over 4 d of storage at 10 °C. Phosphate treatment of fish muscle may serve as a secondary barrier in addition to FDA recommended time and temperature controls for reducing public health concerns of scombrotoxin fish poisoning.

  5. Principles of branch formation and branch patterning in Hydrozoa.

    Science.gov (United States)

    Berking, Stefan

    2006-01-01

    The freshwater polyp Hydra produces buds which separate from the parent. Other Hydrozoa produce branches which remain connected to the parent, thus forming a colony. Some Hydrozoa grow by means of an organ that is like a shoot apical meristem. Others display a sympodial type of growth. In this article, I propose that these different types of branches are organized by a common pattern-forming system. This system has self-organizing properties. It causes branch tip formation and is kept active in the tip when the tip finally differentiates into a hypostome of a polyp. The system does not cause structure formation directly but rather, determines a tissue property called positional value, in such a way that a gradient of values forms in the tissue of the bud or branch. The local value determines the local morphodynamic processes, including differentiation of the hypostome (highest positional value), tentacles and basal disc and of the exoskeleton pattern along the shoot. A high positional value favors the onset of a new self-organizing process and by lateral inhibition, such a process prevents the initiation of a further process in its surroundings. Small quantitative differences in the range of the signals involved determine whether a bud or a branch forms and whether monopodial and sympodial growth follows.

  6. Pattern formation mechanisms in motility mutants of Myxococcus xanthus

    CERN Document Server

    Starruss, Joern; Jakovljevic, Vladimir; Sogaard-Andersen, Lotte; Deutsch, Andreas; Baer, Markus

    2016-01-01

    Formation of spatial patterns of cells is a recurring theme in biology and often depends on regulated cell motility. Motility of M. xanthus depends on two motility machineries: the S-engine and A-engine. Moving M. xanthus cells can organize into spreading colonies or spore-filled fruiting bodies depending on their nutritional status. To understand these two pattern formation processes and the contributions by the two motility machineries, as well as cell reversal, we analyze spatial self-organization in 3 strains: i) a mutant that moves unidirectionally without reversing by the A-motility system only, ii) a unidirectional mutant that is also equipped with the S-motility system, and iii) the wild-type that, in addition to the two motility systems, reverses its direction of movement. The mutant moving by the A-engine illustrates that collective motion in the form of large moving clusters can arise in gliding bacteria due to steric interactions of the rod-shaped cells, without the need of invoking any biochemica...

  7. Chemical Pattern Formation in Far-From Systems.

    Science.gov (United States)

    Pearson, John Evan

    The diffusive instability was proposed as a mechanism for pattern formation in chemical systems, in the context of biological morphogenesis, by Alan Turing in 1952. The instability gives rise to a chemical pattern with an intrinsic "chemical wavelength" that is independent of the system size. Since 1952, the diffusive instability, or Turing bifurcation, has been invoked to explain pattern formation in a variety of fields. To date there has been no unambiguous observation of such an instability. Model studies of the instability are usually carried out on systems containing two variables. Such works do not address issues that are of fundamental importance in experimental studies. How does one go about finding Turing bifurcations in systems with many parameters and for which the chemical kinetics are only partially known? What is the chemical wavelength? Turing bifurcations cannot occur in systems with all diffusion coefficients exactly equal. How unequal must the diffusion coefficients be for a system to undergo a Turing bifurcation?. Reacting and diffusing systems obey a partial -differential equation which is a sum of a diffusion term and a reaction term. Dropping the diffusion term results in an ordinary differential equation describing the reaction kinetics in a well-mixed system. In this dissertation it is shown that, for systems with an arbitrary number of variables, Turing bifurcations can occur with diffusion coefficients arbitrarily close to equal, provided the corresponding well-mixed system is sufficiently close to a point of coalescence of Hopf and saddle-node bifurcations. Since the bifurcation set can be obtained directly from experiments, one does not need a detailed microscopic theory of the reaction kinetics. Similarly, the chemical wavelength can be estimated from experimental measurements without knowledge of the reaction kinetics.

  8. Non-linear pattern formation in bone growth and architecture.

    Science.gov (United States)

    Salmon, Phil

    2014-01-01

    The three-dimensional morphology of bone arises through adaptation to its required engineering performance. Genetically and adaptively bone travels along a complex spatiotemporal trajectory to acquire optimal architecture. On a cellular, micro-anatomical scale, what mechanisms coordinate the activity of osteoblasts and osteoclasts to produce complex and efficient bone architectures? One mechanism is examined here - chaotic non-linear pattern formation (NPF) - which underlies in a unifying way natural structures as disparate as trabecular bone, swarms of birds flying, island formation, fluid turbulence, and others. At the heart of NPF is the fact that simple rules operating between interacting elements, and Turing-like interaction between global and local signals, lead to complex and structured patterns. The study of "group intelligence" exhibited by swarming birds or shoaling fish has led to an embodiment of NPF called "particle swarm optimization" (PSO). This theoretical model could be applicable to the behavior of osteoblasts, osteoclasts, and osteocytes, seeing them operating "socially" in response simultaneously to both global and local signals (endocrine, cytokine, mechanical), resulting in their clustered activity at formation and resorption sites. This represents problem-solving by social intelligence, and could potentially add further realism to in silico computer simulation of bone modeling. What insights has NPF provided to bone biology? One example concerns the genetic disorder juvenile Pagets disease or idiopathic hyperphosphatasia, where the anomalous parallel trabecular architecture characteristic of this pathology is consistent with an NPF paradigm by analogy with known experimental NPF systems. Here, coupling or "feedback" between osteoblasts and osteoclasts is the critical element. This NPF paradigm implies a profound link between bone regulation and its architecture: in bone the architecture is the regulation. The former is the emergent

  9. Pattern formation and mass transfer under stationary solutal Marangoni instability.

    Science.gov (United States)

    Schwarzenberger, Karin; Köllner, Thomas; Linde, Hartmut; Boeck, Thomas; Odenbach, Stefan; Eckert, Kerstin

    2014-04-01

    According to the seminal theory by Sternling and Scriven, solutal Marangoni convection during mass transfer of surface-active solutes may occur as either oscillatory or stationary instability. With strong support of Manuel G. Velarde, a combined initiative of experimental works, in particular to mention those of Linde, Wierschem and coworkers, and theory has enabled a classification of dominant wave types of the oscillatory mode and their interactions. In this way a rather comprehensive understanding of the nonlinear evolution of the oscillatory instability could be achieved. A comparably advanced state-of-the-art with respect to the stationary counterpart seemed to be out of reach a short time ago. Recent developments on both the numerical and experimental side, in combination with assessing an extensive number of older experiments, now allow one to draw a more unified picture. By reviewing these works, we show that three main building blocks exist during the nonlinear evolution: roll cells, relaxation oscillations and relaxation oscillations waves. What is frequently called interfacial turbulence results from the interaction between these partly coexisting basic patterns which may additionally occur in different hierarchy levels. The second focus of this review lies on the practical importance of such convection patterns concerning their influence on mass transfer characteristics. Particular attention is paid here to the interaction between Marangoni and buoyancy effects which frequently complicates the pattern formation even more. To shed more light on these dependencies, new simulations regarding the limiting case of stabilizing density stratification and vanishing buoyancy are incorporated.

  10. Deletion of Dicer in smooth muscle affects voiding pattern and reduces detrusor contractility and neuroeffector transmission.

    Directory of Open Access Journals (Sweden)

    Mardjaneh Karbalaei Sadegh

    Full Text Available MicroRNAs have emerged as important regulators of smooth muscle phenotype and may play important roles in pathogenesis of various smooth muscle related disease states. The aim of this study was to investigate the role of miRNAs for urinary bladder function. We used an inducible and smooth muscle specific Dicer knockout (KO mouse which resulted in significantly reduced levels of miRNAs, including miR-145, miR-143, miR-22, miR125b-5p and miR-27a, from detrusor preparations without mucosa. Deletion of Dicer resulted in a disturbed micturition pattern in vivo and reduced depolarization-induced pressure development in the isolated detrusor. Furthermore, electrical field stimulation revealed a decreased cholinergic but maintained purinergic component of neurogenic activation in Dicer KO bladder strips. The ultrastructure of detrusor smooth muscle cells was well maintained, and the density of nerve terminals was similar. Western blotting demonstrated reduced contents of calponin and desmin. Smooth muscle α-actin, SM22α and myocardin were unchanged. Activation of strips with exogenous agonists showed that depolarization-induced contraction was preferentially reduced; ATP- and calyculin A-induced contractions were unchanged. Quantitative real time PCR and western blotting demonstrated reduced expression of Cav1.2 (Cacna1c. It is concluded that smooth muscle miRNAs play an important role for detrusor contractility and voiding pattern of unrestrained mice. This is mediated in part via effects on expression of smooth muscle differentiation markers and L-type Ca(2+ channels in the detrusor.

  11. Muscle activation patterns in the Nordic hamstring exercise: Impact of prior strain injury.

    Science.gov (United States)

    Bourne, M N; Opar, D A; Williams, M D; Al Najjar, A; Shield, A J

    2016-06-01

    This study aimed to determine: (a) the spatial patterns of hamstring activation during the Nordic hamstring exercise (NHE); (b) whether previously injured hamstrings display activation deficits during the NHE; and (c) whether previously injured hamstrings exhibit altered cross-sectional area (CSA). Ten healthy, recreationally active men with a history of unilateral hamstring strain injury underwent functional magnetic resonance imaging of their thighs before and after six sets of 10 repetitions of the NHE. Transverse (T2) relaxation times of all hamstring muscles [biceps femoris long head (BFlh); biceps femoris short head (BFsh); semitendinosus (ST); semimembranosus (SM)] were measured at rest and immediately after the NHE and CSA was measured at rest. For the uninjured limb, the ST's percentage increase in T2 with exercise was 16.8%, 15.8%, and 20.2% greater than the increases exhibited by the BFlh, BFsh, and SM, respectively (P < 0.002 for all). Previously injured hamstring muscles (n = 10) displayed significantly smaller increases in T2 post-exercise than the homonymous muscles in the uninjured contralateral limb (mean difference -7.2%, P = 0.001). No muscles displayed significant between-limb differences in CSA. During the NHE, the ST is preferentially activated and previously injured hamstring muscles display chronic activation deficits compared with uninjured contralateral muscles. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Hydrodynamic approach to surface pattern formation by ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Mario, E-mail: marioc@upcomillas.es [Grupo Interdisciplinar de Sistemas Complejos (GISC) and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de Ingenieri a - ICAI, Universidad Pontificia Comillas, E-28015 Madrid (Spain); Cuerno, Rodolfo [Departamento de Matematicas and GISC, Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes (Spain)

    2012-02-15

    On the proper timescale, amorphous solids can flow. Solid flow can be observed macroscopically in glaciers or lead pipes, but it can also be artificially enhanced by creating defects. Ion Beam Sputtering (IBS) is a technique in which ions with energies in the 0.110 keV range impact against a solid target inducing defect creation and dynamics, and eroding its surface leading to formation of ordered nanostructures. Despite its technological interest, a basic understanding of nanopattern formation processes occurring under IBS of amorphizable targets has not been clearly established, recent experiments on Si having largely questioned knowledge accumulated during the last two decades. A number of interfacial equations have been proposed in the past to describe these phenomena, typically by adding together different contributions coming from surface diffusion, ion sputtering or mass redistribution, etc. in a non-systematic way. Here, we exploit the general idea of solids flowing due to ion impacts in order to establish a general framework into which different mechanisms (such as viscous flow, stress, diffusion, or sputtering) can be incorporated, under generic physical conservation laws. As opposed to formulating phenomenological interfacial equations, this approach allows to assess systematically the relevance and interplay of different physical mechanisms influencing surface pattern formation by IBS.

  13. Differences in activation patterns in elbow flexor muscles during isometric, concentric and eccentric contractions.

    Science.gov (United States)

    Nakazawa, K; Kawakami, Y; Fukunaga, T; Yano, H; Miyashita, M

    1993-01-01

    To investigate the relative activation of the synergistic muscles during three different types of muscle contraction, the electromyograms (EMG) of two elbow flexor muscles, the biceps brachii (BB) and the brachioradialis (BR), have been compared. To accomplish this eight healthy human subjects performed the following elbow flexions against the same load--concentric, eccentric and isometric contractions. The isometric contractions were performed at three elbow angles: 10, 45 and 90 degrees (0 degree equal to full extension). The EMG were recorded by bipolar surface electrodes, and the relative activation between the two muscles was evaluated as the quotient of mean EMG activities (BR/BB). For the isotonic elbow flexions, BR/BB were calculated at three angle divisions: 0-30 degrees, 30-60 degrees and 60-90 degrees. Results indicated that the relative activation of the BR during the concentric contractions was higher than that of the eccentric contraction, particularly at the extended elbow angles, i.e. the BR/BB of the concentric contractions for the elbow joint angles ranging from 0-30 degrees and 30-60 degrees were significantly greater (P contractions. During the isometric and eccentric contractions, the BR/BB at the flexed joint angles tended to be greater than those at the extended angles. In contrast, there were no angle-dependent BR/BB variations during the concentric elbow flexions. Further, changing patterns in the EMG power spectra due to the type of contraction were different between BB and BR. These results indicated that the activation pattern in the two elbow flexor muscles varied with the muscle contraction pattern.

  14. Formation of hydrogen peroxide and nitric oxide in rat skeletal muscle cells during contractions

    DEFF Research Database (Denmark)

    Silveira, Leonardo R.; Pereira-Da-Silva, Lucia; Juel, Carsten

    2003-01-01

    We examined intra- and extracellular H(2)O(2) and NO formation during contractions in primary rat skeletal muscle cell culture. The fluorescent probes DCFH-DA/DCFH (2,7-dichlorofluorescein-diacetate/2,7-dichlorofluorescein) and DAF-2-DA/DAF-2 (4,5-diaminofluorescein-diacetate/4,5-diaminofluoresce...

  15. Changes in gluteal muscle forces with alteration of footstrike pattern during running.

    Science.gov (United States)

    Vannatta, Charles Nathan; Kernozek, Thomas W; Gheidi, Naghmeh

    2017-08-09

    Gait retraining is a common form of treatment for running related injuries. Proximal factors at the hip have been postulated as having a role in the development of running related injuries. How altering footstrike affects hip muscles forces and kinematics has not been described. Thus, we aimed to quantify differences in hip muscle forces and hip kinematics that may occur when healthy runners are instructed to alter their foot strike pattern from their habitual rear-foot strike to a forefoot strike. This may gain insight on the potential etiology and treatment methods of running related lower extremity injury. Twenty-five healthy female runners completed a minimum of 10 running trials in a controlled laboratory setting under rear-foot strike and instructed forefoot strike conditions. Kinetic and kinematic data were used in an inverse dynamic based static optimization to estimate individual muscle forces during running. Within subject differences were investigated using a repeated measures multi-variate analysis of variance. Peak gluteus medius and minimus and hamstring forces were reduced while peak gluteus maximus force was increased when running with an instructed forefoot strike pattern. Peak hip adduction, hip internal rotation, and heel-COM distance were also reduced. Therefore, instructing habitual rearfoot strike runners to run with a forefoot strike pattern resulted in changes in peak gluteal and hamstring muscle forces and hip kinematics. These changes may be beneficial to the development and treatment of running related lower extremity injury. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Calpain 3 Expression Pattern during Gastrocnemius Muscle Atrophy and Regeneration Following Sciatic Nerve Injury in Rats

    Directory of Open Access Journals (Sweden)

    Ronghua Wu

    2015-11-01

    Full Text Available Calpain 3 (CAPN3, also known as p94, is a skeletal muscle-specific member of the calpain family that is involved in muscular dystrophy; however, the roles of CAPN3 in muscular atrophy and regeneration are yet to be understood. In the present study, we attempted to explain the effect of CAPN3 in muscle atrophy by evaluating CAPN3 expression in rat gastrocnemius muscle following reversible sciatic nerve injury. After nerve injury, the wet weight ratio and cross sectional area (CSA of gastrocnemius muscle were decreased gradually from 1–14 days and then recovery from 14–28 days. The active form of CAPN3 (~62 kDa protein decreased slightly on day 3 and then increased from day 7 to 14 before a decrease from day 14 to 28. The result of linear correlation analysis showed that expression of the active CAPN3 protein level was negatively correlated with muscle wet weight ratio. CAPN3 knockdown by short interfering RNA (siRNA injection improved muscle recovery on days 7 and 14 after injury as compared to that observed with control siRNA treatment. Depletion of CAPN3 gene expression could promote myoblast differentiation in L6 cells. Based on these findings, we conclude that the expression pattern of the active CAPN3 protein is linked to muscle atrophy and regeneration following denervation: its upregulation during early stages may promote satellite cell renewal by inhibiting differentiation, whereas in later stages, CAPN3 expression may be downregulated to stimulate myogenic differentiation and enhance recovery. These results provide a novel mechanistic insight into the role of CAPN3 protein in muscle regeneration after peripheral nerve injury.

  17. Hip flexor muscle size, strength and recruitment pattern in patients with acetabular labral tears compared to healthy controls.

    Science.gov (United States)

    Mendis, M Dilani; Wilson, Stephen J; Hayes, David A; Watts, Mark C; Hides, Julie A

    2014-10-01

    Acetabular labral tears are a source of hip pain and are considered to be a precursor to hip osteoarthritis. Hip flexor muscles contribute to hip joint stability and function but it is unknown if their size and function is altered in the presence of labral pathology. This study aimed to investigate hip flexor muscle size, strength and recruitment pattern in patients with hip labral pathology compared to control subjects. 12 subjects diagnosed with an unilateral acetabular labral tear were compared to 12 control subjects matched for age and gender. All subjects underwent magnetic resonance imaging (MRI) of their lumbo-pelvic region. Average muscle cross-sectional area (CSA) of the iliacus, psoas, iliopsoas, sartorius, tensor fascia latae and rectus femoris muscles were measured. Hip flexion strength was measured by an externally fixed dynamometer. Individual muscle recruitment pattern during a resisted hip flexion exercise task was measured by muscle functional MRI. Hip flexor muscle strength was found to be decreased in patients with labral pathology compared to control subjects (p muscle size (all p > 0.17) and recruitment pattern (all p > 0.53). Decreased hip flexor muscle strength may affect physical function in patients with hip labral pathology by contributing to altered gait patterns and functional tasks. Clinical rehabilitation of these patients may need to include strengthening exercises for the hip flexor muscles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Notch signalling is required for the formation of structurally stable muscle fibres in zebrafish.

    Directory of Open Access Journals (Sweden)

    Susana Pascoal

    Full Text Available BACKGROUND: Accurate regulation of Notch signalling is central for developmental processes in a variety of tissues, but its function in pectoral fin development in zebrafish is still unknown. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that core elements necessary for a functional Notch pathway are expressed in developing pectoral fins in or near prospective muscle territories. Blocking Notch signalling at different levels of the pathway consistently leads to the formation of thin, wavy, fragmented and mechanically weak muscles fibres and loss of stress fibres in endoskeletal disc cells in pectoral fins. Although the structural muscle genes encoding Desmin and Vinculin are normally transcribed in Notch-disrupted pectoral fins, their proteins levels are severely reduced, suggesting that weak mechanical forces produced by the muscle fibres are unable to stabilize/localize these proteins. Moreover, in Notch signalling disrupted pectoral fins there is a decrease in the number of Pax7-positive cells indicative of a defect in myogenesis. CONCLUSIONS/SIGNIFICANCE: We propose that by controlling the differentiation of myogenic progenitor cells, Notch signalling might secure the formation of structurally stable muscle fibres in the zebrafish pectoral fin.

  19. Lin-28 regulates oogenesis and muscle formation in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Vassilis Stratoulias

    Full Text Available Understanding the control of stem cell (SC differentiation is important to comprehend developmental processes as well as to develop clinical applications. Lin28 is a conserved molecule that is involved in SC maintenance and differentiation by regulating let-7 miRNA maturation. However, little is known about the in vivo function of Lin28. Here, we report critical roles for lin-28 during oogenesis. We found that let-7 maturation was increased in lin-28 null mutant fly ovaries. We showed that lin-28 null mutant female flies displayed reduced fecundity, due to defects in egg chamber formation. More specifically, we demonstrated that in mutant ovaries, the egg chambers fuse during early oogenesis resulting in abnormal late egg chambers. We also showed that this phenotype is the combined result of impaired germline SC differentiation and follicle SC differentiation. We suggest a model in which these multiple oogenesis defects result from a misregulation of the ecdysone signaling network, through the fine-tuning of Abrupt and Fasciclin2 expression. Our results give a better understanding of the evolutionarily conserved role of lin-28 on GSC maintenance and differentiation.

  20. Spontaneous pattern formation and pinning in the visual cortex

    Science.gov (United States)

    Baker, Tanya I.

    Bifurcation theory and perturbation theory can be combined with a knowledge of the underlying circuitry of the visual cortex to produce an elegant story explaining the phenomenon of visual hallucinations. A key insight is the application of an important set of ideas concerning spontaneous pattern formation introduced by Turing in 1952. The basic mechanism is a diffusion driven linear instability favoring a particular wavelength that determines the size of the ensuing stripe or spot periodicity of the emerging spatial pattern. Competition between short range excitation and longer range inhibition in the connectivity profile of cortical neurons provides the difference in diffusion length scales necessary for the Turing mechanism to occur and has been proven by Ermentrout and Cowan to be sufficient to explain the generation of a subset of reported geometric hallucinations. Incorporating further details of the cortical circuitry, namely that neurons are also weakly connected to other neurons sharing a particular stimulus orientation or spatial frequency preference at even longer ranges and the resulting shift-twist symmetry of the neuronal connectivity, improves the story. We expand this approach in order to be able to include the tuned responses of cortical neurons to additional visual stimulus features such as motion, color and disparity. We apply a study of nonlinear dynamics similar to the analysis of wave propagation in a crystalline lattice to demonstrate how a spatial pattern formed through the Turing instability can be pinned to the geometric layout of various feature preferences. The perturbation analysis is analogous to solving the Schrodinger equation in a weak periodic potential. Competition between the local isotropic connections which produce patterns of activity via the Turing mechanism and the weaker patchy lateral connections that depend on a neuron's particular set of feature preferences create long wavelength affects analogous to commensurate

  1. Validation of Hill-type muscle models in relation to neuromuscular recruitment and force-velocity properties: predicting patterns of in vivo muscle force.

    Science.gov (United States)

    Biewener, Andrew A; Wakeling, James M; Lee, Sabrina S; Arnold, Allison S

    2014-12-01

    We review here the use and reliability of Hill-type muscle models to predict muscle performance under varying conditions, ranging from in situ production of isometric force to in vivo dynamics of muscle length change and force in response to activation. Muscle models are frequently used in musculoskeletal simulations of movement, particularly when applied to studies of human motor performance in which surgically implanted transducers have limited use. Musculoskeletal simulations of different animal species also are being developed to evaluate comparative and evolutionary aspects of locomotor performance. However, such models are rarely validated against direct measures of fascicle strain or recordings of muscle-tendon force. Historically, Hill-type models simplify properties of whole muscle by scaling salient properties of single fibers to whole muscles, typically accounting for a muscle's architecture and series elasticity. Activation of the model's single contractile element (assigned the properties of homogenous fibers) is also simplified and is often based on temporal features of myoelectric (EMG) activation recorded from the muscle. Comparison of standard one-element models with a novel two-element model and with in situ and in vivo measures of EMG, fascicle strain, and force recorded from the gastrocnemius muscles of goats shows that a two-element Hill-type model, which allows independent recruitment of slow and fast units, better predicts temporal patterns of in situ and in vivo force. Recruitment patterns of slow/fast units based on wavelet decomposition of EMG activity in frequency-time space are generally correlated with the intensity spectra of the EMG signals, the strain rates of the fascicles, and the muscle-tendon forces measured in vivo, with faster units linked to greater strain rates and to more rapid forces. Using direct measures of muscle performance to further test Hill-type models, whether traditional or more complex, remains critical for

  2. Quantifying Contributions of Climate Feedbacks to Global Warming Pattern Formation

    Science.gov (United States)

    Song, X.; Zhang, G. J.; Cai, M.

    2013-12-01

    The ';';climate feedback-response analysis method'' (CFRAM) was applied to the NCAR CCSM3.0 simulation to analyze the strength and spatial distribution of climate feedbacks and to quantify their contributions to global and regional surface temperature changes in response to a doubling of CO2. Instead of analyzing the climate sensitivity, the CFRAM directly attributes the temperature change to individual radiative and non-radiative feedbacks. The radiative feedback decomposition is based on hourly model output rather than monthly mean data that are commonly used in climate feedback analysis. This gives a more accurate quantification of the cloud and albedo feedbacks. The process-based decomposition of non-radiative feedback enables us to understand the roles of GCM physical and dynamic processes in climate change. The pattern correlation, the centered root-mean-square (RMS) difference and the ratio of variations (represented by standard deviations) between the partial surface temperature change due to each feedback process and the total surface temperature change in CCSM3.0 simulation are examined to quantify the roles of each feedback process in the global warming pattern formation. The contributions of climate feedbacks to the regional warming are also discussed.

  3. Tree island pattern formation in the Florida Everglades

    Science.gov (United States)

    Carr, Joel; D'Odorico, P.; Engel, Victor C.; Redwine, Jed

    2016-01-01

    The Florida Everglades freshwater landscape exhibits a distribution of islands covered by woody vegetation and bordered by marshes and wet prairies. Known as “tree islands”, these ecogeomorphic features can be found in few other low gradient, nutrient limited freshwater wetlands. In the last few decades, however, a large percentage of tree islands have either shrank or disappeared in apparent response to altered water depths and other stressors associated with human impacts on the Everglades. Because the processes determining the formation and spatial organization of tree islands remain poorly understood, it is still unclear what controls the sensitivity of these landscapes to altered conditions. We hypothesize that positive feedbacks between woody plants and soil accretion are crucial to emergence and decline of tree islands. Likewise, positive feedbacks between phosphorus (P) accumulation and trees explain the P enrichment commonly observed in tree island soils. Here, we develop a spatially-explicit model of tree island formation and evolution, which accounts for these positive feedbacks (facilitation) as well as for long range competition and fire dynamics. It is found that tree island patterns form within a range of parameter values consistent with field data. Simulated impacts of reduced water levels, increased intensity of drought, and increased frequency of dry season/soil consuming fires on these feedback mechanisms result in the decline and disappearance of tree islands on the landscape.

  4. Ternary eutectic dendrites: Pattern formation and scaling properties

    Energy Technology Data Exchange (ETDEWEB)

    Rátkai, László; Szállás, Attila; Pusztai, Tamás [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest (Hungary); Mohri, Tetsuo [Center for Computational Materials Science, Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Gránásy, László, E-mail: granasy.laszlo@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest (Hungary); Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom)

    2015-04-21

    Extending previous work [Pusztai et al., Phys. Rev. E 87, 032401 (2013)], we have studied the formation of eutectic dendrites in a model ternary system within the framework of the phase-field theory. We have mapped out the domain in which two-phase dendritic structures grow. With increasing pulling velocity, the following sequence of growth morphologies is observed: flat front lamellae → eutectic colonies → eutectic dendrites → dendrites with target pattern → partitionless dendrites → partitionless flat front. We confirm that the two-phase and one-phase dendrites have similar forms and display a similar scaling of the dendrite tip radius with the interface free energy. It is also found that the possible eutectic patterns include the target pattern, and single- and multiarm spirals, of which the thermal fluctuations choose. The most probable number of spiral arms increases with increasing tip radius and with decreasing kinetic anisotropy. Our numerical simulations confirm that in agreement with the assumptions of a recent analysis of two-phase dendrites [Akamatsu et al., Phys. Rev. Lett. 112, 105502 (2014)], the Jackson-Hunt scaling of the eutectic wavelength with pulling velocity is obeyed in the parameter domain explored, and that the natural eutectic wavelength is proportional to the tip radius of the two-phase dendrites. Finally, we find that it is very difficult/virtually impossible to form spiraling two-phase dendrites without anisotropy, an observation that seems to contradict the expectations of Akamatsu et al. Yet, it cannot be excluded that in isotropic systems, two-phase dendrites are rare events difficult to observe in simulations.

  5. Patterns of trunk muscle activation during walking and pole walking using statistical non-parametric mapping.

    Science.gov (United States)

    Zoffoli, Luca; Ditroilo, Massimiliano; Federici, Ario; Lucertini, Francesco

    2017-09-09

    This study used surface electromyography (EMG) to investigate the regions and patterns of activity of the external oblique (EO), erector spinae longissimus (ES), multifidus (MU) and rectus abdominis (RA) muscles during walking (W) and pole walking (PW) performed at different speeds and grades. Eighteen healthy adults undertook W and PW on a motorized treadmill at 60% and 100% of their walk-to-run preferred transition speed at 0% and 7% treadmill grade. The Teager-Kaiser energy operator was employed to improve the muscle activity detection and statistical non-parametric mapping based on paired t-tests was used to highlight statistical differences in the EMG patterns corresponding to different trials. The activation amplitude of all trunk muscles increased at high speed, while no differences were recorded at 7% treadmill grade. ES and MU appeared to support the upper body at the heel-strike during both W and PW, with the latter resulting in elevated recruitment of EO and RA as required to control for the longer stride and the push of the pole. Accordingly, the greater activity of the abdominal muscles and the comparable intervention of the spine extensors supports the use of poles by walkers seeking higher engagement of the lower trunk region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders

    Science.gov (United States)

    Fang, Jia; Liu, Ming-Sheng; Guan, Yu-Zhou; Du, Hua; Li, Ben-Hong; Cui, Bo; Ding, Qing-Yun; Cui, Li-Ying

    2016-01-01

    Background: Amyotrophic lateral sclerosis (ALS) and some mimic disorders, such as distal-type cervical spondylotic amyotrophy (CSA), Hirayama disease (HD), and spinobulbar muscular atrophy (SBMA) may present with intrinsic hand muscle atrophy. This study aimed to investigate different patterns of small hand muscle involvement in ALS and some mimic disorders. Methods: We compared the abductor digiti minimi/abductor pollicis brevis (ADM/APB) compound muscle action potential (CMAP) ratios between 200 ALS patients, 95 patients with distal-type CSA, 88 HD patients, 43 SBMA patients, and 150 normal controls. Results: The ADM/APB CMAP amplitude ratio was significantly higher in the ALS patients (P SBMA patients was similar to that of the normal controls (P = 0.862). An absent APB CMAP and an abnormally high ADM/APB CMAP amplitude ratio (≥4.5) were observed exclusively in the ALS patients. Conclusions: The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders, and may aid in distinguishing between ALS and mimic disorders. PMID:26996473

  7. Muscle activation patterns of the upper and lower extremity during the windmill softball pitch.

    Science.gov (United States)

    Oliver, Gretchen D; Plummer, Hillary A; Keeley, David W

    2011-06-01

    Fast-pitch softball has become an increasingly popular sport for female athletes. There has been little research examining the windmill softball pitch in the literature. The purpose of this study was to describe the muscle activation patterns of 3 upper extremity muscles (biceps, triceps, and rhomboids [scapular stabilizers]) and 2 lower extremity muscles (gluteus maximus and medius) during the 5 phases of the windmill softball pitch. Data describing muscle activation were collected on 7 postpubescent softball pitchers (age 17.7 ± 2.6 years; height 169 ± 5.4 cm; mass 69.1 ± 5.4 kg). Surface electromyographic data were collected using a Myopac Jr 10-channel amplifier (RUN Technologies Scientific Systems, Laguna Hills, CA, USA) synchronized with The MotionMonitor™ motion capture system (Innovative Sports Training Inc, Chicago IL, USA) and presented as a percent of maximum voluntary isometric contraction. Gluteus maximus activity reached (196.3% maximum voluntary isometric contraction [MVIC]), whereas gluteus medius activity was consistent during the single leg support of phase 3 (101.2% MVIC). Biceps brachii activity was greatest during phase 4 of the pitching motion. Triceps brachii activation was consistently >150% MVIC throughout the entire pitching motion, whereas the scapular stabilizers were most active during phase 2 (170.1% MVIC). The results of this study indicate the extent to which muscles are activated during the windmill softball pitch, and this knowledge can lead to the development of proper preventative and rehabilitative muscle strengthening programs. In addition, clinicians will be able to incorporate strengthening exercises that mimic the timing of maximal muscle activation most used during the windmill pitching phases.

  8. Function-based discovery of significant transcriptional temporal patterns in insulin stimulated muscle cells.

    Science.gov (United States)

    Di Camillo, Barbara; Irving, Brian A; Schimke, Jill; Sanavia, Tiziana; Toffolo, Gianna; Cobelli, Claudio; Nair, K Sreekumaran

    2012-01-01

    Insulin action on protein synthesis (translation of transcripts) and post-translational modifications, especially of those involving the reversible modifications such as phosphorylation of various signaling proteins, are extensively studied but insulin effect on transcription of genes, especially of transcriptional temporal patterns remains to be fully defined. To identify significant transcriptional temporal patterns we utilized primary differentiated rat skeletal muscle myotubes which were treated with insulin and samples were collected every 20 min for 8 hours. Pooled samples at every hour were analyzed by gene array approach to measure transcript levels. The patterns of transcript levels were analyzed based on a novel method that integrates selection, clustering, and functional annotation to find the main temporal patterns associated to functional groups of differentially expressed genes. 326 genes were found to be differentially expressed in response to in vitro insulin administration in skeletal muscle myotubes. Approximately 20% of the genes that were differentially expressed were identified as belonging to the insulin signaling pathway. Characteristic transcriptional temporal patterns include: (a) a slow and gradual decrease in gene expression, (b) a gradual increase in gene expression reaching a peak at about 5 hours and then reaching a plateau or an initial decrease and other different variable pattern of increase in gene expression over time. The new method allows identifying characteristic dynamic responses to insulin stimulus, common to a number of genes and associated to the same functional group. The results demonstrate that insulin treatment elicited different clusters of gene transcript profile supporting a temporal regulation of gene expression by insulin in skeletal muscle cells.

  9. Function-based discovery of significant transcriptional temporal patterns in insulin stimulated muscle cells.

    Directory of Open Access Journals (Sweden)

    Barbara Di Camillo

    Full Text Available BACKGROUND: Insulin action on protein synthesis (translation of transcripts and post-translational modifications, especially of those involving the reversible modifications such as phosphorylation of various signaling proteins, are extensively studied but insulin effect on transcription of genes, especially of transcriptional temporal patterns remains to be fully defined. METHODOLOGY/PRINCIPAL FINDINGS: To identify significant transcriptional temporal patterns we utilized primary differentiated rat skeletal muscle myotubes which were treated with insulin and samples were collected every 20 min for 8 hours. Pooled samples at every hour were analyzed by gene array approach to measure transcript levels. The patterns of transcript levels were analyzed based on a novel method that integrates selection, clustering, and functional annotation to find the main temporal patterns associated to functional groups of differentially expressed genes. 326 genes were found to be differentially expressed in response to in vitro insulin administration in skeletal muscle myotubes. Approximately 20% of the genes that were differentially expressed were identified as belonging to the insulin signaling pathway. Characteristic transcriptional temporal patterns include: (a a slow and gradual decrease in gene expression, (b a gradual increase in gene expression reaching a peak at about 5 hours and then reaching a plateau or an initial decrease and other different variable pattern of increase in gene expression over time. CONCLUSION/SIGNIFICANCE: The new method allows identifying characteristic dynamic responses to insulin stimulus, common to a number of genes and associated to the same functional group. The results demonstrate that insulin treatment elicited different clusters of gene transcript profile supporting a temporal regulation of gene expression by insulin in skeletal muscle cells.

  10. Circular and longitudinal muscles shortening indicates sliding patterns during peristalsis and transient lower esophageal sphincter relaxation.

    Science.gov (United States)

    Patel, Nirali; Jiang, Yanfen; Mittal, Ravinder K; Kim, Tae Ho; Ledgerwood, Melissa; Bhargava, Valmik

    2015-09-01

    Esophageal axial shortening is caused by longitudinal muscle (LM) contraction, but circular muscle (CM) may also contribute to axial shortening because of its spiral morphology. The goal of our study was to show patterns of contraction of CM and LM layers during peristalsis and transient lower esophageal sphincter (LES) relaxation (TLESR). In rats, esophageal and LES morphology was assessed by histology and immunohistochemistry, and function with the use of piezo-electric crystals and manometry. Electrical stimulation of the vagus nerve was used to induce esophageal contractions. In 18 healthy subjects, manometry and high frequency intraluminal ultrasound imaging during swallow-induced esophageal contractions and TLESR were evaluated. CM and LM thicknesses were measured (40 swallows and 30 TLESRs) as markers of axial shortening, before and at peak contraction, as well as during TLESRs. Animal studies revealed muscular connections between the LM and CM layers of the LES but not in the esophagus. During vagal stimulated esophageal contraction there was relative movement between the LM and CM. Human studies show that LM-to-CM (LM/CM) thickness ratio at baseline was 1. At the peak of swallow-induced contraction LM/CM ratio decreased significantly (2). The pattern of contraction of CM and LM suggests sliding of the two muscles. Furthermore, the sliding patterns are in the opposite direction during peristalsis and TLESR.

  11. Comparative study of excitation patterns in the masseter muscle before and after orthognathic surgery.

    Science.gov (United States)

    Eckardt, L; Harzer, W; Schneevoigt, R

    1997-12-01

    This study was designed to inquire into changes occurring in the electromyographic activity throughout the masseter muscle after orthognathic surgical treatment of various bite anomalies. A total of 32 adult patients showing distinct class II (n = 15) or class III malocclusions (n = 17) were entered into the investigation. All patients had monopolar surface electromyograms of the masseter muscle taken prior to presurgical orthodontic treatment and after removal of their orthodontic appliances after surgery. Twenty eugnathic adult patients served as controls. Unlike bipolar lead readings, simultaneous sampling from 16 electrodes permits the registration of the overall excitation pattern in the entire muscle. Recordings were taken during clenching, chewing and protrusion of the lower jaw against a defined force. Comparison with preoperative EMGs proved postsurgical distribution of excitation in class 11 patients to approximate the excitation pattern of eugnathic patients. By contrast, correction in class III malocclusions produced a shift in excitation maxima in the sense of a cranial advance. Harmonization, as evident in class II patients, did not occur. The postoperative discords in masseter excitation patterns, as observed after correction of class III anomalies, are indicative of the risk of relapse and the prolonged phase of retention associated with these conditions.

  12. Effects of the foot strike pattern on muscle activity and neuromuscular fatigue in downhill trail running.

    Science.gov (United States)

    Giandolini, M; Horvais, N; Rossi, J; Millet, G Y; Morin, J-B; Samozino, P

    2017-08-01

    Minimizing musculo-skeletal damage and fatigue is considered paramount for performance in trail running. Our purposes were to investigate the effects of the foot strike pattern and its variability on (a) muscle activity during a downhill trail run and (b) immediate and delayed neuromuscular fatigue. Twenty-three runners performed a 6.5-km run (1264 m of negative elevation change). Electromyographic activity of lower-limb muscles was recorded continuously. Heel and metatarsal accelerations were recorded to identify the running technique. Peripheral and central fatigue was assessed in knee extensors (KE) and plantar flexors (PF) at Pre-, Post-, and 2 days post downhill run (Post2d). Anterior patterns were associated with (a) higher gastrocnemius lateralis activity and lower tibialis anterior and vastus lateralis activity during the run and (b) larger decreases in KE high-frequency stimulus-evoked torque Post and larger decrements in KE MVC Post2d. High patterns variability during the run was associated with (a) smaller decreases in KE Db100 Post and MVC Post2d and (b) smaller decreases in PF MVC Post and Post2d. Anterior patterns increase the severity of KE peripheral fatigue. However, high foot strike pattern variability during the run reduced acute and delayed neuromuscular fatigue in KE and PF. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. DAAM is required for thin filament formation and Sarcomerogenesis during muscle development in Drosophila.

    Science.gov (United States)

    Molnár, Imre; Migh, Ede; Szikora, Szilárd; Kalmár, Tibor; Végh, Attila G; Deák, Ferenc; Barkó, Szilvia; Bugyi, Beáta; Orfanos, Zacharias; Kovács, János; Juhász, Gábor; Váró, György; Nyitrai, Miklós; Sparrow, John; Mihály, József

    2014-02-01

    During muscle development, myosin and actin containing filaments assemble into the highly organized sarcomeric structure critical for muscle function. Although sarcomerogenesis clearly involves the de novo formation of actin filaments, this process remained poorly understood. Here we show that mouse and Drosophila members of the DAAM formin family are sarcomere-associated actin assembly factors enriched at the Z-disc and M-band. Analysis of dDAAM mutants revealed a pivotal role in myofibrillogenesis of larval somatic muscles, indirect flight muscles and the heart. We found that loss of dDAAM function results in multiple defects in sarcomere development including thin and thick filament disorganization, Z-disc and M-band formation, and a near complete absence of the myofibrillar lattice. Collectively, our data suggest that dDAAM is required for the initial assembly of thin filaments, and subsequently it promotes filament elongation by assembling short actin polymers that anneal to the pointed end of the growing filaments, and by antagonizing the capping protein Tropomodulin.

  14. DAAM is required for thin filament formation and Sarcomerogenesis during muscle development in Drosophila.

    Directory of Open Access Journals (Sweden)

    Imre Molnár

    2014-02-01

    Full Text Available During muscle development, myosin and actin containing filaments assemble into the highly organized sarcomeric structure critical for muscle function. Although sarcomerogenesis clearly involves the de novo formation of actin filaments, this process remained poorly understood. Here we show that mouse and Drosophila members of the DAAM formin family are sarcomere-associated actin assembly factors enriched at the Z-disc and M-band. Analysis of dDAAM mutants revealed a pivotal role in myofibrillogenesis of larval somatic muscles, indirect flight muscles and the heart. We found that loss of dDAAM function results in multiple defects in sarcomere development including thin and thick filament disorganization, Z-disc and M-band formation, and a near complete absence of the myofibrillar lattice. Collectively, our data suggest that dDAAM is required for the initial assembly of thin filaments, and subsequently it promotes filament elongation by assembling short actin polymers that anneal to the pointed end of the growing filaments, and by antagonizing the capping protein Tropomodulin.

  15. Formation of Nanoscale Bioimprints of Muscle Cells Using UV-Cured Spin-Coated Polymers

    Directory of Open Access Journals (Sweden)

    Fahmi Samsuri

    2009-01-01

    Full Text Available We report a nanoscale replication method suitable for biological specimens that has potential in single cell studies and in formation of 3D biocompatible scaffolds. Earlier studies using a heat-curable polydimethylsiloxane (PDMS or a UV-curable elastomer introduced Bioimprint replication to facilitate cell imaging. However, the replicating conditions for thermal polymerization are known to cause cell dehydration during curing. In this study, a UV-cured methacrylate copolymer was developed for use in creating replicas of living cells and was tested on rat muscle cells. Bioimprints of muscle cells were formed by spin coating under UV irradiation. The polymer replicas were then separated from the muscle cells and were analyzed under an Atomic Force Microscope (AFM, in tapping mode, because it has low tip-sample forces and thus will not destroy the fine structures of the imprint. The new polymer is biocompatible with higher replication resolution and has a faster curing process than other types of silicon-based organic polymers such as PDMS. High resolution images of the muscle cell imprints showed the micro-and nanostructures of the muscle cells, including cellular fibers and structures within the cell membranes. The AFM is able to image features at nanoscale resolution with the potential for recognizing abnormalities on cell membranes at early stages of disease progression.

  16. Endpoint force fluctuations reveal flexible rather than synergistic patterns of muscle cooperation.

    Science.gov (United States)

    Kutch, Jason J; Kuo, Arthur D; Bloch, Anthony M; Rymer, William Z

    2008-11-01

    We developed a new approach to investigate how the nervous system activates multiple redundant muscles by studying the endpoint force fluctuations during isometric force generation at a multi-degree-of-freedom joint. We hypothesized that, due to signal-dependent muscle force noise, endpoint force fluctuations would depend on the target direction of index finger force and that this dependence could be used to distinguish flexible from synergistic activation of the musculature. We made high-gain measurements of isometric forces generated to different target magnitudes and directions, in the plane of index finger metacarpophalangeal joint abduction-adduction/flexion-extension. Force fluctuations from each target were used to calculate a covariance ellipse, the shape of which varied as a function of target direction. Directions with narrow ellipses were approximately aligned with the estimated mechanical actions of key muscles. For example, targets directed along the mechanical action of the first dorsal interosseous (FDI) yielded narrow ellipses, with 88% of the variance directed along those target directions. It follows the FDI is likely a prime mover in this target direction and that, at most, 12% of the force variance could be explained by synergistic coupling with other muscles. In contrast, other target directions exhibited broader covariance ellipses with as little as 30% of force variance directed along those target directions. This is the result of cooperation among multiple muscles, based on independent electromyographic recordings. However, the pattern of cooperation across target directions indicates that muscles are recruited flexibly in accordance with their mechanical action, rather than in fixed groupings.

  17. Exercise-induced rib stress fractures: potential risk factors related to thoracic muscle co-contraction and movement pattern

    DEFF Research Database (Denmark)

    Vinther-Knudsen, Archibald; Kanstrup, I-L; Christiansen, E

    2006-01-01

    The etiology of exercise-induced rib stress fractures (RSFs) in elite rowers is unclear. The purpose of the study was to investigate thoracic muscle activity, movement patterns and muscle strength in elite rowers. Electromyographic (EMG) and 2-D video analysis were performed during ergometer rowi...

  18. Pattern Formation in Dewetting Nanoparticle/Polymer Bilayers

    Science.gov (United States)

    Esker, Alan; Paul, Rituparna; Karabiyik, Ufuk; Swift, Michael; Hottle, John

    2008-03-01

    Comprised of inorganic cores and flexible organic coronae with 1 -- 2 nm diameter monodisperse sizes, polyhedral oligomeric silsesquioxanes (POSS) are ideal model nanofillers. Our discovery that one POSS derivative, trisilanolphenyl-POSS (TPP), can form Langmuir-Blodgett (LB) films on hydrophobic substrates, allows us to create thin film bilayers of precisely controlled thickness and architecture. Work with poly(t-butylacrylate) (PtBA)/TPP bilayers reveals a two-step dewetting mechanism in which the upper TPP layer dewets first, followed by the formation of isolated holes with intricate, fractal, nanofiller aggregates. Like the PtBA/TPP bilayers, polystyrene (PS)/TPP bilayers also undergo a two-step dewetting mechanism. However, the upper TPP layer initially forms cracks that may arise from mismatches in thermal expansion coefficients. These cracks then serve as nucleation sites for complete dewetting of the entire bilayer. Understanding the rich diversity of surface patterns that can be formed from relatively simple processes is a key feature of this work.

  19. Gradient-driven diffusion and pattern formation in crowded mixtures

    Science.gov (United States)

    Nandigrami, Prithviraj; Grove, Brandy; Konya, Andrew; Selinger, Robin L. B.

    2017-02-01

    Gradient-driven diffusion in crowded, multicomponent mixtures is a topic of high interest because of its role in biological processes such as transport in cell membranes. In partially phase-separated solutions, gradient-driven diffusion affects microstructure, which in turn affects diffusivity; a key question is how this complex coupling controls both transport and pattern formation. To examine these mechanisms, we study a two-dimensional multicomponent lattice gas model, where "tracer" molecules diffuse between a source and a sink separated by a solution of sticky "crowder" molecules that cluster to form dynamically evolving obstacles. In the high-temperature limit, crowders and tracers are miscible, and transport may be predicted analytically. At intermediate temperatures, crowders phase separate into clusters that drift toward the tracer sink. As a result, steady-state tracer diffusivity depends nonmonotonically on both temperature and crowder density, and we observe a variety of complex microstructures. In the low-temperature limit, crowders rapidly aggregate to form obstacles that are kinetically arrested; if crowder density is near the percolation threshold, resulting tracer diffusivity shows scaling behavior with the same scaling exponent as the random resistor network model. Though highly idealized, this simple model reveals fundamental mechanisms governing coupled gradient-driven diffusion, phase separation, and microstructural evolution in crowded mixtures.

  20. Phasic bursts of the antagonistic jaw muscles during REM sleep mimic a coordinated motor pattern during mastication

    National Research Council Canada - National Science Library

    T. Kato; N. Nakamura; Y. Masuda; A. Yoshida; T. Morimoto; K. Yamamura; S. Yamashita; F. Sato

    2013-01-01

    .... In this study, jaw-closing and -opening muscle electromyographic (EMG) activities and jaw movements were quantified to characterize phenotypes of motor patterns during sleep in freely moving and head-restrained guinea pigs...

  1. The pattern of muscle involvement in ulnar neuropathy at the elbow

    Directory of Open Access Journals (Sweden)

    Dariush Eliaspour

    2012-01-01

    Full Text Available Objective: To determine the pattern of muscle involvement in patients with ulnar neuropathy at the elbow. Materials and Methods: This study evaluated all patients referred for upper limb electrodiagnostic study (EDX during 2007-2011 and included. patients with clinical signs and symptoms of ulnar neuropathy at the elbow. All patients had nerve conduction studies (NCS for ulnar neuropathy. Needle electromyography (EMG of four ulnar innervated muscles, flexor carpi ulnaris (FCU, flexor digitrom profoundus (FDP, first dorsal interosseous (FDI and abductor digiti minimi (ADM was evaluated. Results: During the study period 34 (23 males and 11 females patients were diagnosed with ulnar neuropathy at the elbow and three of them had bilateral involvement. Muscle involvement by EMG was as follows: FDI: 91.9%, ADM: 91.3%, FCU: 64.9% and FDP: 56.8%. Conclusion: In this study, EMG abnormalities of nerve damage were presented more commonly in the FCU muscle than in the FDP in patients with ulnar nerve lesion at the elbow.

  2. Biomathematical pattern of EMG signal propagation in smooth muscle of the non-pregnant porcine uterus

    Science.gov (United States)

    Domino, Malgorzata; Pawlinski, Bartosz; Gajewski, Zdzislaw

    2017-01-01

    Uterine contractions are generated by myometrial smooth muscle cells (SMCs) that comprise most of the myometrial layer of the uterine wall. Aberrant uterine motility (i.e., hypo- or hyper-contractility or asynchronous contractions) has been implicated in the pathogenesis of infertility due to the failure of implantation, endometriosis and abnormal estrous cycles. The mechanism whereby the non-pregnant uterus initiates spontaneous contractions remains poorly understood. The aim of the present study was to employ linear synchronization measures for analyzing the pattern of EMG signal propagation (direction and speed) in smooth muscles of the non-pregnant porcine uterus in vivo using telemetry recording system. It has been revealed that the EMG signal conduction in the uterine wall of the non-pregnant sow does not occur at random but it rather exhibits specific directions and speed. All detectable EMG signals moved along the uterine horn in both cervico-tubal and tubo-cervical directions. The signal migration speed could be divided into the three main types or categories: i. slow basic migration rhythm (SBMR); ii. rapid basic migration rhythm (RBMR); and iii. rapid accessory migration rhythm (RAMR). In conclusion, the EMG signal propagation in smooth muscles of the porcine uterus in vivo can be assessed using a linear synchronization model. Physiological pattern of the uterine contractile activity determined in this study provides a basis for future investigations of normal and pathologicall myogenic function of the uterus. PMID:28282410

  3. Impact of lumbar spine posture on thoracic spine motion and muscle activation patterns.

    Science.gov (United States)

    Nairn, Brian C; Drake, Janessa D M

    2014-10-01

    Complex motion during standing is typical in daily living and requires movement of both the thoracic and lumbar spine; however, the effects of lumbar spine posture on thoracic spine motion patterns remain unclear. Thirteen males moved to six positions involving different lumbar (neutral and flexed) and thoracic (flexed and twisted) posture combinations. The thoracic spine was partitioned into three segments and the range of motion from each posture was calculated. Electromyographical data were collected from eight muscles bilaterally. Results showed that with a flexed lumbar spine, the lower-thoracic region had 14.83 ° and 15.6 1 ° more flexion than the upper- and mid-thoracic regions, respectively. A flexed lumbar spine significantly reduced the mid-thoracic axial twist angle by 5.21 ° compared to maximum twist in the mid-thoracic region. Functional differences emerged across muscles, as low back musculature was greatest in maintaining flexed lumbar postures, while thoracic erector spinae and abdominals showed bilateral differences with greater activations to the ipsilateral side. Combined postures have been previously identified as potential injury modulators and bilateral muscle patterns can have an effect on loading pathways. Overall, changes in thoracic motion were modified by lumbar spine posture, highlighting the importance of considering a multi-segmented approach when analyzing trunk motion. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Pattern recognition control outperforms conventional myoelectric control in upper limb patients with targeted muscle reinnervation.

    Science.gov (United States)

    Hargrove, Levi J; Lock, Blair A; Simon, Ann M

    2013-01-01

    Pattern recognition myoelectric control shows great promise as an alternative to conventional amplitude based control to control multiple degree of freedom prosthetic limbs. Many studies have reported pattern recognition classification error performances of less than 10% during offline tests; however, it remains unclear how this translates to real-time control performance. In this contribution, we compare the real-time control performances between pattern recognition and direct myoelectric control (a popular form of conventional amplitude control) for participants who had received targeted muscle reinnervation. The real-time performance was evaluated during three tasks; 1) a box and blocks task, 2) a clothespin relocation task, and 3) a block stacking task. Our results found that pattern recognition significantly outperformed direct control for all three performance tasks. Furthermore, it was found that pattern recognition was configured much quicker. The classification error of the pattern recognition systems used by the patients was found to be 16% ±(1.6%) suggesting that systems with this error rate may still provide excellent control. Finally, patients qualitatively preferred using pattern recognition control and reported the resulting control to be smoother and more consistent.

  5. Robust conversion of marrow cells to skeletal muscle with formation of marrow-derived muscle cell colonies: A multifactorial process

    Energy Technology Data Exchange (ETDEWEB)

    Abedi, Mehrdad; Greer, Deborah A.; Colvin, Gerald A.; Demers, Delia A.; Dooner, Mark S.; Harpel, Jasha A.; Weier, Heinz-Ulrich G.; Lambert, Jean-Francois; Quesenberry, Peter J.

    2004-01-10

    Murine marrow cells are capable of repopulating skeletal muscle fibers. A point of concern has been the robustness of such conversions. We have investigated the impact of type of cell delivery, muscle injury, nature of delivered cell, and stem cell mobilizations on marrow to muscle conversion. We transplanted GFP transgenic marrow into irradiated C57BL/6 mice and then injured anterior tibialis muscle by cardiotoxin. One month after injury, sections were analyzed by standard and deconvolutional microscopy for expression of muscle and hematopietic markers. Irradiation was essential to conversion although whether by injury or induction of chimerism is not clear. Cardiotoxin and to a lesser extent PBS injected muscles showed significant number of GFP+ muscle fibers while uninjected muscles showed only rare GFP+ cells. Marrow conversion to muscle was increased by two cycles of G-CSF mobilization and to a lesser extent with G-CSF and steel or GM-CSF. Transplantation of female GFP to male C57 BL/6 and GFP to Rosa26 mice showed fusion of donor cells to recipient muscle. High numbers of donor derived muscle colonies and up to12 percent GFP positive muscle cells were seen after mobilization or direct injection. These levels of donor muscle chimerism approach levels which could be clinically significant in developing strategies for the treatment of muscular dystrophies. In summary, the conversion of marrow to skeletal muscle cells is based on cell fusion and is critically dependent on injury. This conversion is also numerically significant and increases with mobilization.

  6. Skeletal Muscle Regeneration on Protein-Grafted and Microchannel-Patterned Scaffold for Hypopharyngeal Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Zhisen Shen

    2013-01-01

    Full Text Available In the field of tissue engineering, polymeric materials with high biocompatibility like polylactic acid and polyglycolic acid have been widely used for fabricating living constructs. For hypopharynx tissue engineering, skeletal muscle is one important functional part of the whole organ, which assembles the unidirectionally aligned myotubes. In this study, a polyurethane (PU scaffold with microchannel patterns was used to provide aligning guidance for the seeded human myoblasts. Due to the low hydrophilicity of PU, the scaffold was grafted with silk fibroin (PU-SF or gelatin (PU-Gel to improve its cell adhesion properties. Scaffolds were observed to degrade slowly over time, and their mechanical properties and hydrophilicities were improved through the surface grafting. Also, the myoblasts seeded on PU-SF had the higher proliferative rate and better differentiation compared with those on the control or PU-Gel. Our results demonstrate that polyurethane scaffolds seeded with myoblasts hold promise to guide hypopharynx muscle regeneration.

  7. Skeletal muscle regeneration on protein-grafted and microchannel-patterned scaffold for hypopharyngeal tissue engineering.

    Science.gov (United States)

    Shen, Zhisen; Guo, Shanshan; Ye, Dong; Chen, Jingjing; Kang, Cheng; Qiu, Shejie; Lu, Dakai; Li, Qun; Xu, Kunjie; Lv, Jingjing; Zhu, Yabin

    2013-01-01

    In the field of tissue engineering, polymeric materials with high biocompatibility like polylactic acid and polyglycolic acid have been widely used for fabricating living constructs. For hypopharynx tissue engineering, skeletal muscle is one important functional part of the whole organ, which assembles the unidirectionally aligned myotubes. In this study, a polyurethane (PU) scaffold with microchannel patterns was used to provide aligning guidance for the seeded human myoblasts. Due to the low hydrophilicity of PU, the scaffold was grafted with silk fibroin (PU-SF) or gelatin (PU-Gel) to improve its cell adhesion properties. Scaffolds were observed to degrade slowly over time, and their mechanical properties and hydrophilicities were improved through the surface grafting. Also, the myoblasts seeded on PU-SF had the higher proliferative rate and better differentiation compared with those on the control or PU-Gel. Our results demonstrate that polyurethane scaffolds seeded with myoblasts hold promise to guide hypopharynx muscle regeneration.

  8. Referred Pain Patterns of the Infraspinatus Muscle Elicited by Deep Dry Needling and Manual Palpation.

    Science.gov (United States)

    Poveda-Pagán, Emilio J; Lozano-Quijada, Carlos; Segura-Heras, Jose V; Peral-Berna, María; Lumbreras, Blanca

    2017-03-07

    To identify the most common referred pain (ReP) pattern of the infraspinatus myofascial trigger point (MTrP) and compare its coincidence with the original ReP pattern, to verify whether there are any significant differences by sex and types of technique and to determine the observed signs and symptoms evoked by deep dry needling (DDN) and manual palpation (MPal). A cohort study of patients randomized to two different examination methods (July and August 2016). Students and staff recruited from Miguel Hernandez University (Southeast Spain). One hundred thirty-three participants (70.7% women) with shoulder complaints were randomly assigned to either an MPal (n = 67) or DDN group (n = 66). The same physiotherapist carried out the techniques on all participants, and the same protocol was followed for both the DDN and MPal groups. The physiotherapist did not ask participants about their pain features or other relevant issues. Local twitch response (LTR) and ReP assessed through a visual analogue scale and features of ReP of the infraspinatus muscle. The areas with the highest percentage of ReP were the front (area 3; 27.1%) and back (area 11; 21.1%) of the arm, anterior (area 4; 36.1%) and posterior (area 12; 42.1%) shoulder, and infraspinatus muscle area. DDN proved to be significantly easier than MPal in evoking an LTR (p ≤ 0.001). There were significant differences between sexes in zone 2 (p = 0.041) and no statistically significant differences were found by technique. The ReP pattern of the infraspinatus muscle coincides with the original pattern described by Travell and Simons, although the neck area should be questioned. The study found no significant differences in the ReP pattern by sex and when comparing MPal with DDN of MTrP of the infraspinatus muscle. DDN proved to be significantly easier than MPal in evoking an LTR.

  9. Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders

    Institute of Scientific and Technical Information of China (English)

    Jia Fang; Ming-Sheng Liu; Yu-Zhou Guan; Hua Du; Ben-Hong Li; Bo Cui; Qing-Yun Ding

    2016-01-01

    Background:Amyotrophic lateral sclerosis (ALS) and some mimic disorders,such as distal-type cervical spondylotic amyotrophy (CSA),Hirayama disease (HD),and spinobulbar muscular atrophy (SBMA) may present with intrinsic hand muscle atrophy.This study aimed to investigate different patterns of small hand muscle involvement in ALS and some mimic disorders.Methods:We compared the abductor digiti minimi/abductor pollicis brevis (ADM/APB) compound muscle action potential (CMAP) ratios between 200 ALS patients,95 patients with distal-type CSA,88 HD patients,43 SBMA patients,and 150 normal controls.Results:The ADM/APB CMAP amplitude ratio was significantly higher in the ALS patients (P < 0.001) than that in the normal controls.The ADM/APB CMAP amplitude ratio was significantly reduced in the patients with distal-type CSA (P < 0.001) and the HD patients (P < 0.001) compared with that in the normal controls.The patients with distal-type CSA had significantly lower APB CMAP amplitude than the HD patients (P =0.004).The ADM/APB CMAP amplitude ratio was significantly lower in the HD patients (P < 0.001) than that in the patients with distal-type CSA.The ADM/APB CMAP amplitude ratio of the SBMA patients was similar to that of the normal controls (P =0.862).An absent APB CMAP and an abnormally high ADM/APB CMAP amplitude ratio (>4.5) were observed exclusively in the ALS patients.Conclusions:The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders,and may aid in distinguishing between ALS and mimic disorders.

  10. Patterns of gene expression in atrophying skeletal muscles: response to food deprivation

    Science.gov (United States)

    Jagoe, R. Thomas; Lecker, Stewart H.; Gomes, Marcelo; Goldberg, Alfred L.

    2002-01-01

    During fasting and many systemic diseases, muscle undergoes rapid loss of protein and functional capacity. To define the transcriptional changes triggering muscle atrophy and energy conservation in fasting, we used cDNA microarrays to compare mRNAs from muscles of control and food-deprived mice. Expression of >94% of genes did not change, but interesting patterns emerged among genes that were differentially expressed: 1) mRNAs encoding polyubiquitin, ubiquitin extension proteins, and many (but not all) proteasome subunits increased, which presumably contributes to accelerated protein breakdown; 2) a dramatic increase in mRNA for the ubiquitin ligase, atrogin-1, but not most E3s; 3) a significant suppression of mRNA for myosin binding protein H (but not other myofibrillar proteins) and IGF binding protein 5, which may favor cell protein loss; 4) decreases in mRNAs for several glycolytic enzymes and phosphorylase kinase subunits, and dramatic increases in mRNAs for pyruvate dehydrogenase kinase 4 and glutamine synthase, which should promote glucose sparing and gluconeogenesis. During fasting, metallothionein mRNA increased dramatically, mRNAs for extracellular matrix components fell, and mRNAs that may favor cap-independent mRNA translation rose. Significant changes occurred in mRNAs for many growth-related proteins and transcriptional regulators. These transcriptional changes indicate a complex adaptive program that should favor protein degradation and suppress glucose oxidation in muscle. Similar analysis of muscles atrophying for other causes is allowing us to identify a set of atrophy-specific changes in gene expression.

  11. The mechanical power output of the pectoralis muscle of cockatiel (Nymphicus hollandicus): the in vivo muscle length trajectory and activity patterns and their implications for power modulation.

    Science.gov (United States)

    Morris, Charlotte R; Askew, Graham N

    2010-08-15

    In order to meet the varying demands of flight, pectoralis muscle power output must be modulated. In birds with pectoralis muscles with a homogeneous fibre type composition, power output can be modulated at the level of the motor unit (via changes in muscle length trajectory and the pattern of activation), at the level of the muscle (via changes in the number of motor units recruited), and at the level of the whole animal (through the use of intermittent flight). Pectoralis muscle length trajectory and activity patterns were measured in vivo in the cockatiel (Nymphicus hollandicus) at a range of flight speeds (0-16 m s(-1)) using sonomicrometry and electromyography. The work loop technique was used to measure the mechanical power output of a bundle of fascicles isolated from the pectoralis muscle during simulated in vivo length change and activity patterns. The mechanical power-speed relationship was U-shaped, with a 2.97-fold variation in power output (40-120 W kg(-1)). In this species, modulation of neuromuscular activation is the primary strategy utilised to modulate pectoralis muscle power output. Maximum in vivo power output was 22% of the maximum isotonic power output (533 W kg(-1)) and was generated at a lower relative shortening velocity (0.28 V(max)) than the maximum power output during isotonic contractions (0.34 V(max)). It seems probable that the large pectoralis muscle strains result in a shift in the optimal relative shortening velocity in comparison with the optimum during isotonic contractions as a result of length-force effects.

  12. Equine postanesthetic forelimb lameness: intracompartmental muscle pressure changes and biochemical patterns.

    Science.gov (United States)

    Lindsay, W A; McDonell, W; Bignell, W

    1980-12-01

    Intracompartmental muscle pressures were recorded from the right and left forelimbs (extensor carpi radialis, triceps brachii) of healthy horses maintained in left lateral recumbency while under deep halothane anesthesia for 180 to 240 minutes. Cardiac output, blood pressure, blood gases, and acid-base status were monitored throughout the anesthesia, and electrolyte levels (Ca2+, P+, K+, Cl-, Na+) and enzyme activities (aspartate aminotransferase (AST), creatine phosphokinase (CPK), and blood lactate) were monitored for 7 days. Postanesthetic forelimb lameness was produced in 5 of the 6 horses with this prolonged anesthetic regime. This lameness was associated with muscle plaque formation and clinical signs which were similar to the forelimb lameness sometimes seen in horses after surgical anesthesia. Plasma protein, serum calcium, plasma sodium, and blood urea nitrogen concentrations did not change, whereas significantly increased hematocrit, plasma potassium, and serum inorganic phosphate values were seen at the end of anesthesia, along with a decrease in plasma chloride values. Blood lactate, serum AST, and serum CPK activities were significantly high in the postanesthetic period, although the sequence of the changes differed. Intracompartmental muscle pressures were higher in the left forelimb adjacent to the floor (contact limb), and in the instance of the triceps of the contact limb, the pressures were sufficiently high (greater than 30 mm of Hg) that they may have compromised capillary blood flow. However, these high intracompartmental muscle pressures did not persist when positional changes of the horses were introduced at the end of the anesthetic period. There was no correlation between the severity of postanesthetic lameness and any of the measured values. The results demonstrate an experimentally induced postanesthetic lameness which was primarily related to the development of a myositis. Although the causative factors of this myositis may be multiple

  13. Dynamic formation of microenvironments at the myotendinous junction correlates with muscle fiber morphogenesis in zebrafish.

    Science.gov (United States)

    Snow, Chelsi J; Henry, Clarissa A

    2009-01-01

    Muscle development involves the specification and morphogenesis of muscle fibers that attach to tendons. After attachment, muscles and tendons then function as an integrated unit to transduce force to the skeletal system and stabilize joints. The attachment site is the myotendinous junction, or MTJ, and is the primary site of force transmission. We find that attachment of fast-twitch myofibers to the MTJ correlates with the formation of novel microenvironments within the MTJ. The expression or activation of two proteins involved in anchoring the intracellular cytoskeleton to the extracellular matrix, Focal adhesion kinase (Fak) and beta-dystroglycan is up-regulated. Conversely, the extracellular matrix protein Fibronectin (Fn) is down-regulated. This degradation of Fn as fast-twitch fibers attach to the MTJ results in Fn protein defining a novel microenvironment within the MTJ adjacent to slow-twitch, but not fast-twitch, muscle. Interestingly, however, Fak, laminin, Fn and beta-dystroglycan concentrate at the MTJ in mutants that do not have slow-twitch fibers. Taken together, these data elucidate novel and dynamic microenvironments within the MTJ and indicate that MTJ morphogenesis is spatially and temporally complex.

  14. Evidence of a central pattern generator regulating spermathecal muscle activity in Locusta migratoria and its coordination with oviposition.

    Science.gov (United States)

    da Silva, Rosa; Lange, Angela B

    2011-03-01

    Electrophysiological recordings were conducted to determine the control of spermathecal contractions during oviposition of interrupted egg-laying locusts, Locusta migratoria. Following transection of the central nervous system below the metathoracic ganglion, rhythmic patterned bursting was detected by extracellular recordings of the nerve N2B2 that innervates the muscles of the spermatheca. Subsequent transections at more posterior regions of the ventral nerve cord revealed more robust rhythmic bursting in N2B2. This rhythmic bursting pattern was found to be coordinated with bursting in the ventral opener nerve (N2B1) that innervates the ventral opener muscle. This muscle controls the ventral ovipositor valves. Electromyographic recordings from the spermathecal muscle and ventral opener muscle confirmed a rhythmic bursting pattern resulting in an increase in muscle activity. Taken together, the results indicate that there is probably a central pattern generator (CPG), which is regulated by descending inhibition, that controls the spermathecal muscle activity. This CPG appears to be located within the VIIth and VIIIth abdominal ganglia, and was found to integrate with the CPG that regulates oviposition digging in locusts. These results provide further insight into the intricate coordination and control of reproductive tissues underlying reproductive behaviours in locusts.

  15. Quantify work load and muscle functional activation patterns in neck-shoulder muscles of female sewing machine operators using surface electromyogram.

    Science.gov (United States)

    Zhang, Fei-Ruo; He, Li-Hua; Wu, Shan-Shan; Li, Jing-Yun; Ye, Kang-Pin; Wang, Sheng

    2011-11-01

    Work-related musculoskeletal disorders (WMSDs) have high prevalence in sewing machine operators employed in the garment industry. Long work duration, sustained low level work and precise hand work are the main risk factors of neck-shoulder disorders for sewing machine operators. Surface electromyogram (sEMG) offers a valuable tool to determine muscle activity (internal exposure) and quantify muscular load (external exposure). During sustained and/or repetitive muscle contractions, typical changes of muscle fatigue in sEMG, as an increase in amplitude or a decrease as a shift in spectrum towards lower frequencies, can be observed. In this paper, we measured and quantified the muscle load and muscular activity patterns of neck-shoulder muscles in female sewing machine operators during sustained sewing machine operating tasks using sEMG. A total of 18 healthy women sewing machine operators volunteered to participate in this study. Before their daily sewing machine operating task, we measured the maximal voluntary contractions (MVC) and 20%MVC of bilateral cervical erector spinae (CES) and upper trapezius (UT) respectively, then the sEMG signals of bilateral UT and CES were monitored and recorded continuously during 200 minutes of sustained sewing machine operating simultaneously which equals to 20 time windows with 10 minutes as one time window. After 200 minutes' work, we retest 20%MVC of four neck-shoulder muscles and recorded the sEMG signals. Linear analysis, including amplitude probability distribution frequency (APDF), amplitude analysis parameters such as roof mean square (RMS) and spectrum analysis parameter as median frequency (MF), were used to calculate and indicate muscle load and muscular activity of bilateral CES and UT. During 200 minutes of sewing machine operating, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezius (LUT) and right upper trapezius (RUT) were 6.78%MVE, 6.94%MVE, 6

  16. Magnitudes of gluteus medius muscle activation during standing hip joint movements in spiral-diagonal patterns using elastic tubing resistance.

    Science.gov (United States)

    Youdas, James W; Adams, Kady E; Bertucci, John E; Brooks, Koel J; Steiner, Meghan M; Hollman, John H

    2015-01-01

    The aim of this study was to simultaneously quantify electromyographic (EMG) activation levels (% maximum voluntary isometric contraction [MVIC]) within the gluteus medius muscles on both moving and stance limbs across the performance of four proprioceptive neuromuscular facilitation (PNF) spiral-diagonal patterns in standing using resistance provided by elastic tubing. Differential EMG activity was recorded from the gluteus medius muscle of 26 healthy participants. EMG signals were collected with surface electrodes at a sampling frequency of 1000 Hz during three consecutive repetitions of each spiral-diagonal movement pattern. Significant differences existed among the four-spiral-diagonal movement patterns (F3,75 = 19.8; p < 0.001). The diagonal two flexion [D2F] pattern produced significantly more gluteus medius muscle recruitment (50 SD 29.3% MVIC) than any of the other three patterns and the diagonal one extension [D1E] (39 SD 37% MVIC) and diagonal two extension [D2E] (35 SD 29% MVIC) patterns generated more gluteus medius muscle recruitment than diagonal one flexion [D1F] (22 SD 21% MVIC). From a clinical efficiency standpoint, a fitness professional using the spiral-diagonal movement pattern of D2F and elastic tubing with an average peak tension of about 9% body mass may be able to concurrently strengthen the gluteus medius muscle on both stance and moving lower limbs.

  17. Loss of Tropomodulin4 in the zebrafish mutant träge causes cytoplasmic rod formation and muscle weakness reminiscent of nemaline myopathy

    Directory of Open Access Journals (Sweden)

    Joachim Berger

    2014-12-01

    Full Text Available Nemaline myopathy is an inherited muscle disease that is mainly diagnosed by the presence of nemaline rods in muscle biopsies. Of the nine genes associated with the disease, five encode components of striated muscle sarcomeres. In a genetic zebrafish screen, the mutant träge (trg was isolated based on its reduction in muscle birefringence, indicating muscle damage. Myofibres in trg appeared disorganised and showed inhomogeneous cytoplasmic eosin staining alongside malformed nuclei. Linkage analysis of trg combined with sequencing identified a nonsense mutation in tropomodulin4 (tmod4, a regulator of thin filament length and stability. Accordingly, although actin monomers polymerize to form thin filaments in the skeletal muscle of tmod4trg mutants, thin filaments often appeared to be dispersed throughout myofibres. Organised myofibrils with the typical striation rarely assemble, leading to severe muscle weakness, impaired locomotion and early death. Myofibrils of tmod4trg mutants often featured thin filaments of various lengths, widened Z-disks, undefined H-zones and electron-dense aggregations of various shapes and sizes. Importantly, Gomori trichrome staining and the lattice pattern of the detected cytoplasmic rods, together with the reactivity of rods with phalloidin and an antibody against actinin, is reminiscent of nemaline rods found in nemaline myopathy, suggesting that misregulation of thin filament length causes cytoplasmic rod formation in tmod4trg mutants. Although Tropomodulin4 has not been associated with myopathy, the results presented here implicateTMOD4 as a novel candidate for unresolved nemaline myopathies and suggest that the tmod4trg mutant will be a valuable tool to study human muscle disorders.

  18. Loss of Tropomodulin4 in the zebrafish mutant träge causes cytoplasmic rod formation and muscle weakness reminiscent of nemaline myopathy.

    Science.gov (United States)

    Berger, Joachim; Tarakci, Hakan; Berger, Silke; Li, Mei; Hall, Thomas E; Arner, Anders; Currie, Peter D

    2014-12-01

    Nemaline myopathy is an inherited muscle disease that is mainly diagnosed by the presence of nemaline rods in muscle biopsies. Of the nine genes associated with the disease, five encode components of striated muscle sarcomeres. In a genetic zebrafish screen, the mutant träge (trg) was isolated based on its reduction in muscle birefringence, indicating muscle damage. Myofibres in trg appeared disorganised and showed inhomogeneous cytoplasmic eosin staining alongside malformed nuclei. Linkage analysis of trg combined with sequencing identified a nonsense mutation in tropomodulin4 (tmod4), a regulator of thin filament length and stability. Accordingly, although actin monomers polymerize to form thin filaments in the skeletal muscle of tmod4(trg) mutants, thin filaments often appeared to be dispersed throughout myofibres. Organised myofibrils with the typical striation rarely assemble, leading to severe muscle weakness, impaired locomotion and early death. Myofibrils of tmod4(trg) mutants often featured thin filaments of various lengths, widened Z-disks, undefined H-zones and electron-dense aggregations of various shapes and sizes. Importantly, Gomori trichrome staining and the lattice pattern of the detected cytoplasmic rods, together with the reactivity of rods with phalloidin and an antibody against actinin, is reminiscent of nemaline rods found in nemaline myopathy, suggesting that misregulation of thin filament length causes cytoplasmic rod formation in tmod4(trg) mutants. Although Tropomodulin4 has not been associated with myopathy, the results presented here implicateTMOD4 as a novel candidate for unresolved nemaline myopathies and suggest that the tmod4(trg) mutant will be a valuable tool to study human muscle disorders. © 2014. Published by The Company of Biologists Ltd.

  19. BMP9-Induced Osteogenetic Differentiation and Bone Formation of Muscle-Derived Stem Cells

    Directory of Open Access Journals (Sweden)

    Li Xiang

    2012-01-01

    Full Text Available Efficient osteogenetic differentiation and bone formation from muscle-derived stem cells (MDSCs should have potential clinical applications in treating nonunion fracture healing or bone defects. Here, we investigate osteogenetic differentiation ability of MDSCs induced by bone morphogenetic protein 9 (BMP9 in vitro and bone formation ability in rabbit radius defects repairing model. Rabbit's MDSCs were extracted by type I collagenase and trypsin methods, and BMP9 was introduced into MDSCs by infection with recombinant adenovirus. Effects of BMP9-induced osteogenetic differentiation of MDSCs were identified with alkaline phosphatase (ALP activity and expression of later marker. In stem-cell implantation assay, MDSCs have also shown valuable potential bone formation ability induced by BMP9 in rabbit radius defects repairing test. Taken together, our findings suggest that MDSCs are potentiated osteogenetic stem cells which can be induced by BMP9 to treat large segmental bone defects, nonunion fracture, and/or osteoporotic fracture.

  20. Unique formation of sciatic nerve below the piriformis muscle - a case report.

    Science.gov (United States)

    Patil, Jyothsna; Swamy, Ravindra S; Rao, Mohandas K G; Kumar, Naveen; Somayaji, S N

    2014-01-01

    Dorsal and ventral divisions of ventral rami of lower lumbar and sacral spinal nerve were found to pass ventral and dorsal to the piriformis muscle respectively. These divisions joined each other below the piriformis muscle to form sciatic nerve. This low formation of sciatic nerve was observed in distal part of left gluteal region of a 50-year-old male cadaver. The sciatic nerve thus formed passed caudally into back of thigh and divided into tibial and common peroneal nerves in the upper part of popliteal fossa. In addition, a communicating nerve from the sciatic nerve was found to join the common peroneal nerve in the popliteal fossa. Such variations may lead to piriformis syndrome or non-discogenic sciatica.

  1. Altered Expression Pattern of Molecular Factors Involved in Colonic Smooth Muscle Functions: An Immunohistochemical Study in Patients with Diverticular Disease

    Science.gov (United States)

    Mattii, Letizia; Ippolito, Chiara; Segnani, Cristina; Battolla, Barbara; Colucci, Rocchina; Dolfi, Amelio; Bassotti, Gabrio; Blandizzi, Corrado; Bernardini, Nunzia

    2013-01-01

    Background The pathogenesis of diverticular disease (DD) is thought to result from complex interactions among dietary habits, genetic factors and coexistence of other bowel abnormalities. These conditions lead to alterations in colonic pressure and motility, facilitating the formation of diverticula. Although electrophysiological studies on smooth muscle cells (SMCs) have investigated colonic motor dysfunctions, scarce attention has been paid to their molecular abnormalities, and data on SMCs in DD are lacking. Accordingly, the main purpose of this study was to evaluate the expression patterns of molecular factors involved in the contractile functions of SMCs in the tunica muscularis of colonic specimens from patients with DD. Methods and Findings By means of immunohistochemistry and image analysis, we examined the expression of Cx26 and Cx43, which are prominent components of gap junctions in human colonic SMCs, as well as pS368-Cx43, PKCps, RhoA and αSMA, all known to regulate the functions of gap junctions and the contractile activity of SMCs. The immunohistochemical analysis revealed significant abnormalities in DD samples, concerning both the expression and distribution patterns of most of the investigated molecular factors. Conclusion This study demonstrates, for the first time, that an altered pattern of factors involved in SMC contractility is present at level of the tunica muscularis of DD patients. Moreover, considering that our analysis was conducted on colonic tissues not directly affected by diverticular lesions or inflammatory reactions, it is conceivable that these molecular alterations may precede and predispose to the formation of diverticula, rather than being mere consequences of the disease. PMID:23437299

  2. The mechanism of pattern formation in the developing drosophila retina

    Institute of Scientific and Technical Information of China (English)

    SUN QiCheng

    2007-01-01

    The biological patterning of the drosophila retina in vivo has striking resemblance to liquid bubbles, in which the surface mechanics due to N-cadherin within a sub-group of retina cells can be mimicked by surface tension. In this work, the aggregating patterns were reasonably simplified into 2D clusters consisting of 2-6 identical bubbles confined within a shrinking boundary. By using a hybrid fluid dynamics model proposed for liquid foams, the aggregating process of 2-6 retina cells was studied. Assuming the minimal perimeter for patterning cells to be the condition of stability patterns, the stable converged patterns we simulated in this work are the same as the experimental observations. More importantly, a new pattern of 6 cells was obtained which was found physically more stable than the other two reported by Hayashi and Carthew[1]. Aggregating perimeters of cells, i.e. the surface energy, showed a good linear fit with the cell numbers.

  3. The mechanism of pattern formation in the developing drosophila retina

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The biological patterning of the drosophila retina in vivo has striking resemblance to liquid bubbles, in which the surface mechanics due to N-cadherin within a sub-group of retina cells can be mimicked by surface tension. In this work, the aggregating patterns were reasonably simplified into 2D clusters consisting of 2—6 identical bubbles confined within a shrinking boundary. By using a hybrid fluid dy-namics model proposed for liquid foams, the aggregating process of 2―6 retina cells was studied. Assuming the minimal perimeter for patterning cells to be the condition of stability patterns, the stable converged patterns we simulated in this work are the same as the experimental observations. More importantly, a new pattern of 6 cells was obtained which was found physically more stable than the other two reported by Hayashi and Carthew[1]. Aggregating perimeters of cells, i.e. the surface energy, showed a good linear fit with the cell numbers.

  4. Muscular dystrophy begins early in embryonic development deriving from stem cell loss and disrupted skeletal muscle formation.

    Science.gov (United States)

    Merrick, Deborah; Stadler, Lukas Kurt Josef; Larner, Dean; Smith, Janet

    2009-01-01

    Examination of embryonic myogenesis of two distinct, but functionally related, skeletal muscle dystrophy mutants (mdx and cav-3(-/-)) establishes for the first time that key elements of the pathology of Duchenne muscular dystrophy (DMD) and limb-girdle muscular dystrophy type 1C (LGMD-1c) originate in the disruption of the embryonic cardiac and skeletal muscle patterning processes. Disruption of myogenesis occurs earlier in mdx mutants, which lack a functional form of dystrophin, than in cav-3(-/-) mutants, which lack the Cav3 gene that encodes the protein caveolin-3; this finding is consistent with the milder phenotype of LGMD-1c, a condition caused by mutations in Cav3, and the earlier [embryonic day (E)9.5] expression of dystrophin. Myogenesis is severely disrupted in mdx embryos, which display developmental delays; myotube morphology and displacement defects; and aberrant stem cell behaviour. In addition, the caveolin-3 protein is elevated in mdx embryos. Both cav-3(-/-) and mdx mutants (from E15.5 and E11.5, respectively) exhibit hyperproliferation and apoptosis of Myf5-positive embryonic myoblasts; attrition of Pax7-positive myoblasts in situ; and depletion of total Pax7 protein in late gestation. Furthermore, both cav-3(-/-) and mdx mutants have cardiac defects. In cav-3(-/-) mutants, there is a more restricted phenotype comprising hypaxial muscle defects, an excess of malformed hypertrophic myotubes, a twofold increase in myonuclei, and reduced fast myosin heavy chain (FMyHC) content. Several mdx mutant embryo pathologies, including myotube hypotrophy, reduced myotube numbers and increased FMyHC, have reciprocity with cav-3(-/-) mutants. In double mutant (mdxcav-3(+/-)) embryos that are deficient in dystrophin (mdx) and heterozygous for caveolin-3 (cav-3(+/-)), whereby caveolin-3 is reduced to 50% of wild-type (WT) levels, these phenotypes are severely exacerbated: intercostal muscle fibre density is reduced by 71%, and Pax7-positive cells are depleted

  5. SDF-1 controls the muscle and blood vessel formation of the somite.

    Science.gov (United States)

    Abduelmula, Aisha; Huang, Ruijin; Pu, Qin; Tamamura, Hirokazu; Morosan-Puopolo, Gabriela; Brand-Saberi, Beate

    2016-01-01

    Stromal-cell-derived factor-1 (SDF-1), the only ligand of the chemokine receptor CXCR4, is involved in skeletal muscle development. However, its role in the proliferation, differentiation and migration of somite cells is not well understood. Here, we investigated its function during somite development in chicken embryos by using gain-of-function and loss-of-function experiments. Overexpression of SDF-1 was performed by electroporating SDF-1 constructs into the ventrolateral part of the somite, or by injecting SDF-1-expressing cells into the somites of stages HH14-16 chicken embryos. We found that enhanced SDF-1 signaling induced cell proliferation in the somite. This resulted in an increase in number of both myotomal and endothelial cells. In contrast, inhibition of SDF-1/CXCR4 signaling led to a reduction of myotomal cells. Injection of SDF-1 producing cells into the somite induced ectopic localization of myotomal cells in the sclerotome. Although many SDF-1-expressing somite cells colonized the limb, only a few of them developed into muscle cells. This resulted in a reduction of the limb muscle mass. This means that most myogenic progenitors were stopped on their migration towards the limb due to the high concentration of the SDF-1 signal in the somite. Most of the SDF-1-expressing somite cells found in the limb were of endothelial cell fate and they contributed to the increase in limb blood vessels. These results reveal that SDF-1 promotes the proliferation of both myogenic and angiogenic progenitor cells of the somite and controls myotome formation. Furthermore, SDF-1 controls muscle and blood vessel formation in the limb in different ways.

  6. Acute vascular endothelial growth factor expression during hypertrophy is muscle phenotype specific and localizes as a striated pattern within fibres.

    Science.gov (United States)

    Parvaresh, Kevin C; Huber, Ashley M; Brochin, Robert L; Bacon, Phoebe L; McCall, Gary E; Huey, Kimberly A; Hyatt, Jon-Philippe K

    2010-11-01

    Skeletal muscle hypertrophy requires the co-ordinated expression of locally acting growth factors that promote myofibre growth and concurrent adaptive changes in the microvasculature. These studies tested the hypothesis that vascular endothelial growth factor (VEGF) and heparin-binding epidermal growth factor (HB-EGF) expression are upregulated during the early stages of compensatory muscle growth induced by chronic functional overload (FO). Bilateral FO of the plantaris and soleus muscles was induced for 3 or 7 days in the hindlimbs of adult female Sprague-Dawley rats (n = 5 per group) and compared with control (non-FO) rats. Relative muscle mass (in mg (kg body weight)(-1)) increased by 18 and 24% after 3 days and by 20 and 33% after 7 days in the plantaris and soleus muscles, respectively. No differences in HB-EGF mRNA or protein were observed in either muscle of FO rats relative to control muscles. The VEGF mRNA was similar in the soleus muscles of FO and control rats, whereas a significant elevation occurred at 3 and 7 days of FO in the plantaris muscle. However, VEGF protein expression after 3 days of FO exhibited a differential response; expression in the soleus muscle decreased 1.6-fold, whereas that in the plantaris muscle increased 1.8-fold compared with the control muscle. After 7 days of FO, VEGF protein remained elevated within the plantaris muscle, but returned to basal levels in the soleus. Robust basal HB-EGF and VEGF protein expression was consistently seen in control muscles. In all groups, immunohistochemistry for VEGF protein displayed a distinct striated expression pattern within myofibres, with considerably less labelling in extracellular spaces. Constitutive expression of HB-EGF and VEGF in control myofibres is consistent with housekeeping roles for these growth factors in skeletal muscle tissue. However, the specific patterns of VEGF expression in these muscles during FO may reflect the chronic changes in neural recruitment between muscles

  7. Genome-wide DNA methylation patterns and transcription analysis in sheep muscle.

    Directory of Open Access Journals (Sweden)

    Christine Couldrey

    Full Text Available DNA methylation plays a central role in regulating many aspects of growth and development in mammals through regulating gene expression. The development of next generation sequencing technologies have paved the way for genome-wide, high resolution analysis of DNA methylation landscapes using methodology known as reduced representation bisulfite sequencing (RRBS. While RRBS has proven to be effective in understanding DNA methylation landscapes in humans, mice, and rats, to date, few studies have utilised this powerful method for investigating DNA methylation in agricultural animals. Here we describe the utilisation of RRBS to investigate DNA methylation in sheep Longissimus dorsi muscles. RRBS analysis of ∼1% of the genome from Longissimus dorsi muscles provided data of suitably high precision and accuracy for DNA methylation analysis, at all levels of resolution from genome-wide to individual nucleotides. Combining RRBS data with mRNAseq data allowed the sheep Longissimus dorsi muscle methylome to be compared with methylomes from other species. While some species differences were identified, many similarities were observed between DNA methylation patterns in sheep and other more commonly studied species. The RRBS data presented here highlights the complexity of epigenetic regulation of genes. However, the similarities observed across species are promising, in that knowledge gained from epigenetic studies in human and mice may be applied, with caution, to agricultural species. The ability to accurately measure DNA methylation in agricultural animals will contribute an additional layer of information to the genetic analyses currently being used to maximise production gains in these species.

  8. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    This work addresses the metal nanocluster growth process on prepatterned substrates, the development of atomistic simulation method with respect to an acceleration of the atomistic transition states, and the continuum model of the ion-beam inducing semiconductor surface pattern formation mechanism. Experimentally, highly ordered Ag nanocluster structures have been grown on pre-patterned amorphous SiO{sub 2} surfaces by oblique angle physical vapor deposition at room temperature. Despite the small undulation of the rippled surface, the stripe-like Ag nanoclusters are very pronounced, reproducible and well-separated. The first topic is the investigation of this growth process with a continuum theoretical approach to the surface gas condensation as well as an atomistic cluster growth model. The atomistic simulation model is a lattice-based kinetic Monte-Carlo (KMC) method using a combination of a simplified inter-atomic potential and experimental transition barriers taken from the literature. An effective transition event classification method is introduced which allows a boost factor of several thousand compared to a traditional KMC approach, thus allowing experimental time scales to be modeled. The simulation predicts a low sticking probability for the arriving atoms, millisecond order lifetimes for single Ag monomers and {approx}1 nm square surface migration ranges of Ag monomers. The simulations give excellent reproduction of the experimentally observed nanocluster growth patterns. The second topic specifies the acceleration scheme utilized in the metallic cluster growth model. Concerning the atomistic movements, a classical harmonic transition state theory is considered and applied in discrete lattice cells with hierarchical transition levels. The model results in an effective reduction of KMC simulation steps by utilizing a classification scheme of transition levels for thermally activated atomistic diffusion processes. Thermally activated atomistic movements

  9. Staufen1 impairs stress granule formation in skeletal muscle cells from myotonic dystrophy type 1 patients

    Science.gov (United States)

    Ravel-Chapuis, Aymeric; Klein Gunnewiek, Amanda; Bélanger, Guy; Crawford Parks, Tara E.; Côté, Jocelyn; Jasmin, Bernard J.

    2016-01-01

    Myotonic dystrophy (DM1) is caused by an expansion of CUG repeats (CUGexp) in the DMPK mRNA 3′UTR. CUGexp-containing mRNAs become toxic to cells by misregulating RNA-binding proteins. Here we investigated the consequence of this RNA toxicity on the cellular stress response. We report that cell stress efficiently triggers formation of stress granules (SGs) in proliferating, quiescent, and differentiated muscle cells, as shown by the appearance of distinct cytoplasmic TIA-1– and DDX3-containing foci. We show that Staufen1 is also dynamically recruited into these granules. Moreover, we discovered that DM1 myoblasts fail to properly form SGs in response to arsenite. This blockage was not observed in DM1 fibroblasts, demonstrating a cell type–specific defect. DM1 myoblasts display increased expression and sequestration of toxic CUGexp mRNAs compared with fibroblasts. Of importance, down-regulation of Staufen1 in DM1 myoblasts rescues SG formation. Together our data show that Staufen1 participates in the inhibition of SG formation in DM1 myoblasts. These results reveal that DM1 muscle cells fail to properly respond to stress, thereby likely contributing to the complex pathogenesis of DM1. PMID:27030674

  10. Synergists activation pattern of the quadriceps muscle differs when performing sustained isometric contractions with different EMG biofeedback.

    Science.gov (United States)

    Place, Nicolas; Matkowski, Boris; Martin, Alain; Lepers, Romuald

    2006-10-01

    The aims of the present study were to examine (1) endurance time and (2) activation pattern of vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) muscles during fatiguing isometric knee extensions performed with different EMG biofeedbacks. Thirteen men (27 +/- 5 year) volunteered to participate in three experimental sessions. Each session involved a submaximal isometric contraction held until failure at an EMG level corresponding to 40% maximal voluntary contraction torque (MVC), with visual EMG biofeedback provided for either (1) RF muscle (RF task), (2) VL and VM muscles (Vasti task) or (3) the sum of the VL, VM and RF muscles (Quadriceps task). EMG activity of VL, VM and RF muscles was recorded during each of the three tasks and further analyzed. Time to task failures and MVC loss (P 0.05) between the three sessions (182 s and approximately 28%, respectively) (P > 0.05). Moreover, the magnitude of central and peripheral fatigue was not different at failure of the three tasks. Activation pattern was similar for knee extensors at the beginning of each task (P > 0.05). However, RF EMG activity decreased (P pattern for the bi-articular RF muscle compared to the mono-articular vasti muscles during fatigue.

  11. Meta-analysis of muscle transcriptome data using the MADMuscle database reveals biologically relevant gene patterns

    Directory of Open Access Journals (Sweden)

    Teusan Raluca

    2011-02-01

    Full Text Available Abstract Background DNA microarray technology has had a great impact on muscle research and microarray gene expression data has been widely used to identify gene signatures characteristic of the studied conditions. With the rapid accumulation of muscle microarray data, it is of great interest to understand how to compare and combine data across multiple studies. Meta-analysis of transcriptome data is a valuable method to achieve it. It enables to highlight conserved gene signatures between multiple independent studies. However, using it is made difficult by the diversity of the available data: different microarray platforms, different gene nomenclature, different species studied, etc. Description We have developed a system tool dedicated to muscle transcriptome data. This system comprises a collection of microarray data as well as a query tool. This latter allows the user to extract similar clusters of co-expressed genes from the database, using an input gene list. Common and relevant gene signatures can thus be searched more easily. The dedicated database consists in a large compendium of public data (more than 500 data sets related to muscle (skeletal and heart. These studies included seven different animal species from invertebrates (Drosophila melanogaster, Caenorhabditis elegans and vertebrates (Homo sapiens, Mus musculus, Rattus norvegicus, Canis familiaris, Gallus gallus. After a renormalization step, clusters of co-expressed genes were identified in each dataset. The lists of co-expressed genes were annotated using a unified re-annotation procedure. These gene lists were compared to find significant overlaps between studies. Conclusions Applied to this large compendium of data sets, meta-analyses demonstrated that conserved patterns between species could be identified. Focusing on a specific pathology (Duchenne Muscular Dystrophy we validated results across independent studies and revealed robust biomarkers and new pathways of interest

  12. The Effects of Neuregulin on Synapse Formation in Primary Muscle/Nerve Co-Cultures

    Directory of Open Access Journals (Sweden)

    Jessica Walsh

    2007-06-01

    Full Text Available In development, motor neurons innervate maturing myotubes to form the neuromuscular junction (NMJ. During this process, the nerve terminal secretes a protein called neuregulin (NRG1. NRG1 acts as a signal which increases the number of acetylcholine receptors (AChRs on the postsynaptic membrane. NRG1 binds to receptors on the surface of the muscle, known as erbB receptors. The binding of NRG1 causes the erbB receptor to auto-phosphorylate (Fu, 1999. As a result, there is an increase in transcription of the gene for AchRs, integral membrane proteins that respond to the binding of the neurotransmitter acetylcholine. In order to study the effects of NRG1 on early stages of synapse formation, we prepared co-cultures of dissociated muscle cells from postnatal day 1 (P1 mice and neural tube explants from embryonic day 11 (E11 mice. Silicone chambers were created as a system for growing dissociated muscle cells and neuronal explants in co-culture (Loeb, 1999. ErbB inhibitor (PD 158780 was added to chambers prior to the formation of the NMJ. After one week the tissue was fixed and stained to visualize the synapses. Based on the results of two experiments, the chambers that were not treated with the inhibitor had an average of 10 times more AchR (+ contacts. Therefore, at the time point studied, it appears that NRG1 signaling through the erbB receptor tyrosine kinases is necessary for the formation of AchR (+ receptor contacts at the motor terminal in the post-synaptic membrane.

  13. Stabilization and destabilization effects of the electric field on stochastic precipitate pattern formation

    NARCIS (Netherlands)

    Lagzi, István; Izsák, Ferenc

    2004-01-01

    Stabilization and destabilization effects of an applied electric field on the Liesegang pattern formation in low concentration gradient were studied with numerical model simulations. In the absence of an electric field pattern formation exhibits increasingly stochastic behaviour as the initial conce

  14. Optical Pattern Formation in Cold Atoms: Explaining the Red-Blue Asymmetry

    Science.gov (United States)

    Schmittberger, Bonnie; Gauthier, Daniel

    2013-05-01

    The study of pattern formation in atomic systems has provided new insight into fundamental many-body physics and low-light-level nonlinear optics. Pattern formation in cold atoms in particular is of great interest in condensed matter physics and quantum information science because atoms undergo self-organization at ultralow input powers. We recently reported the first observation of pattern formation in cold atoms but found that our results were not accurately described by any existing theoretical model of pattern formation. Previous models describing pattern formation in cold atoms predict that pattern formation should occur using both red and blue-detuned pump beams, favoring a lower threshold for blue detunings. This disagrees with our recent work, in which we only observed pattern formation with red-detuned pump beams. Previous models also assume a two-level atom, which cannot account for the cooling processes that arise when beams counterpropagate through a cold atomic vapor. We describe a new model for pattern formation that accounts for Sisyphus cooling in multi-level atoms, which gives rise to a new nonlinearity via spatial organization of the atoms. This spatial organization causes a sharp red-blue detuning asymmetry, which agrees well with our experimental observations. We gratefully acknowledge the financial support of the NSF through Grant #PHY-1206040.

  15. Cortical excitability differences in hand muscles follow a split-hand pattern in healthy controls.

    Science.gov (United States)

    Menon, Parvathi; Kiernan, Matthew C; Vucic, Steve

    2014-06-01

    Differences in cortical and axonal excitability may underlie preferential atrophy of abductor pollicis brevis (APB) and first dorsal interosseous (FDI) in amyotrophic lateral sclerosis, termed the split-hand. Consequently, this study aimed to determine whether differences in excitability follow a split-hand pattern across the intrinsic hand muscles. Excitability studies were undertaken using threshold tracking techniques in 26 healthy controls with responses recorded over APB, FDI, and abductor digiti minimi. Short interval intracortical inhibition was significantly greater from the APB and FDI. In addition, motor evoked potential amplitude was greater, while cortical silent period was longer from APB and FDI. At a peripheral level, the strength-duration time constant was greater when recorded over APB. This study establishes that differences in cortical excitability follow the split-hand pattern in healthy controls, a finding potentially explained by evolution of specialized activity of APB/FDI in complex hand tasks. Muscle Nerve 49: 836-844, 2014. Copyright © 2014 Wiley Periodicals, Inc.

  16. Distribution patterns and predilection muscles of Trichinella zimbabwensis larvae in experimentally infected Nile crocodiles (Crocodylus niloticus Laurenti

    Directory of Open Access Journals (Sweden)

    Louis J. La Grange

    2014-02-01

    Full Text Available No controlled studies have been conducted to determine the predilection muscles of Trichinella zimbabwensis larvae in Nile crocodiles (Crocodylus niloticus or the influence of infection intensity on the distribution of the larvae in crocodiles. The distribution of larvae in muscles of naturally infected Nile crocodiles and experimentally infected caimans (Caiman crocodilus and varans (Varanus exanthematicus have been reported in literature. To determine the distribution patterns of T. zimbabwensis larvae and predilection muscles, 15 crocodiles were randomly divided into three cohorts of five animals each, representing high infection (642 larvae/kg of bodyweight average, medium infection (414 larvae/kg of bodyweight average and low infection (134 larvae/kg of bodyweight average cohorts. In the high infection cohort, high percentages of larvae were observed in the triceps muscles (26% and hind limb muscles (13%. In the medium infection cohort, high percentages of larvae were found in the triceps muscles (50%, sternomastoid (18% and hind limb muscles (13%. In the low infection cohort, larvae were mainly found in the intercostal muscles (36%, longissimus complex (27%, forelimb muscles (20% and hind limb muscles (10%. Predilection muscles in the high and medium infection cohorts were similar to those reported in naturally infected crocodiles despite changes in infection intensity. The high infection cohort had significantly higher numbers of larvae in the sternomastoid, triceps, intercostal, longissimus complex, external tibial flexor, longissimus caudalis and caudal femoral muscles (p < 0.05 compared with the medium infection cohort. In comparison with the low infection cohort, the high infection cohort harboured significantly higher numbers of larvae in all muscles (p < 0.05 except for the tongue. The high infection cohort harboured significantly higher numbers of larvae (p < 0.05 in the sternomastoid, triceps, intercostal, longissimus complex

  17. Simulations demonstrate a simple network to be sufficient to control branch point selection, smooth muscle and vasculature formation during lung branching morphogenesis

    Directory of Open Access Journals (Sweden)

    Géraldine Cellière

    2012-06-01

    Proper lung functioning requires not only a correct structure of the conducting airway tree, but also the simultaneous development of smooth muscles and vasculature. Lung branching morphogenesis is strongly stereotyped and involves the recursive use of only three modes of branching. We have previously shown that the experimentally described interactions between Fibroblast growth factor (FGF10, Sonic hedgehog (SHH and Patched (Ptc can give rise to a Turing mechanism that not only reproduces the experimentally observed wildtype branching pattern but also, in part counterintuitive, patterns in mutant mice. Here we show that, even though many proteins affect smooth muscle formation and the expression of Vegfa, an inducer of blood vessel formation, it is sufficient to add FGF9 to the FGF10/SHH/Ptc module to successfully predict simultaneously the emergence of smooth muscles in the clefts between growing lung buds, and Vegfa expression in the distal sub-epithelial mesenchyme. Our model reproduces the phenotype of both wildtype and relevant mutant mice, as well as the results of most culture conditions described in the literature.

  18. MicroRNA expression profiling in skeletal muscle reveals different regulatory patterns in high and low responders to resistance training.

    Science.gov (United States)

    Ogasawara, Riki; Akimoto, Takayuki; Umeno, Tokushi; Sawada, Shuji; Hamaoka, Takafumi; Fujita, Satoshi

    2016-04-01

    Large variability exists in muscle adaptive response to resistance exercise (RE) training between individuals. Recent studies have revealed a significant role for microRNAs (miRNAs) in skeletal muscle plasticity. In this study, we investigated how RE affects miRNA expression and whether the variability of muscle hypertrophy to RE training may be attributed to differential miRNA regulation in the skeletal muscle. To screen high and low responders to RE, we had 18 young men perform arm curl exercise training. After screening, all the men performed 12 wk of lower body RE training, but only the high or low responders participated in the acute RE test before training. Muscle biopsies were obtained from the vastus lateralis muscle at baseline, 3 h after acute RE, and after the training period. Total RNA was extracted from the skeletal muscle, and miRNA expression (800 miRNAs) was analyzed. RE training increased the cross-sectional area of the biceps brachii (-1.7-26.1%), quadriceps (2.2-16.8%), and hamstrings (1.6-18.4%). Eighty-five and 102 miRNAs were differentially expressed after acute and chronic RE, respectively (P muscle between high and low responders, indicating that the expression patterns of several miRNAs are altered by acute or chronic RE, and that miRNAs are involved in skeletal muscle adaptation to RE training.

  19. Convection-driven pattern formation in lawn grasses

    Science.gov (United States)

    Thompson, Sally; Daniels, Karen

    2009-11-01

    Spatial patterns of 'dead' lawn grass have often been ascribed to Turing-type reaction-diffusion processes related to water scarcity. We present an alternative hypothesis: that the air within the grass canopy is unstable to a convective instability, such that chill damage caused by falling cold air is responsible for the creation of brown and green bands of grass. This hypothesis is consistent with several features of small-scale vegetation patterns, including their length scale, rapid onset and transient nature. We find that the predictions of a porous medium convection model based are consistent with measurements made for a particular instance of lawn-patterning in North Carolina.

  20. The role of hydrological transience in peatland pattern formation

    Science.gov (United States)

    Morris, P. J.; Baird, A. J.; Belyea, L. R.

    2013-10-01

    The sloping flanks of peatlands are commonly patterned with non-random, contour-parallel stripes of distinct micro-habitats such as hummocks, lawns and hollows. Patterning seems to be governed by feedbacks among peatland hydrological processes, plant micro-succession, plant litter production and peat decomposition. An improved understanding of peatland patterning may provide important insights into broader aspects of the long-term development of peatlands and their likely response to future climate change. We recreated a cellular simulation model from the literature, as well as three subtle variants of the model, to explore the controls on peatland patterning. Our models each consist of three submodels, which simulate: peatland water tables in a gridded landscape, micro-habitat dynamics in response to water-table depths, and changes in peat hydraulic properties. We found that the strength and nature of simulated patterning was highly dependent on the degree to which water tables had reached a steady state in response to hydrological inputs. Contrary to previous studies, we found that under a true steady state the models predict largely unpatterned landscapes that cycle rapidly between contrasting dry and wet states, dominated by hummocks and hollows, respectively. Realistic patterning only developed when simulated water tables were still transient. Literal interpretation of the degree of hydrological transience required for patterning suggests that the model should be discarded; however, the transient water tables appear to have inadvertently replicated an ecological memory effect that may be important to peatland patterning. Recently buried peat layers may remain hydrologically active despite no longer reflecting current vegetation patterns, thereby highlighting the potential importance of three-dimensional structural complexity in peatlands to understanding the two-dimensional surface-patterning phenomenon. The models were highly sensitive to the assumed values

  1. [Retroperitoneal dedifferentiated liposarcoma extending into the iliocostal muscle and the quadratus lumborum muscle accompanied with bone formation: case report].

    Science.gov (United States)

    Matsuura, H; Sakurai, M; Arima, K

    2001-12-01

    A 72-year-old man with back pain on the left side was admitted. Imaging analysis revealed a retroperitoneal mass and a mass in the left iliocostal muscle and the left quadratus lumborum muscle. The two masses could not be resected en bloc, and were resected separately. The clinicopathological findings of these tumors revealed dedifferentiated liposarcoma. The primary dedifferentiated liposarcoma appeared to have originated from the retroperitoneal space extending into the iliocostal muscle and the quadratus lumborum muscle. Then the mass was thought to have formed accompanied with osteogenesis.

  2. Estimating dew formation in rice, using seasonally averaged diel patterns of weather variables

    OpenAIRE

    Luo, W.; Goudriaan, J.

    2004-01-01

    If dew formation cannot be measured it has to be estimated. Available simulation models for estimating dew formation require hourly weather data as input. However, such data are not available for places without an automatic weather station. In such cases the diel pattern of weather variables might be used to run the simulation model. To investigate the possibility of using diel patterns of weather variables to estimate dew formation, a field experiment was carried out from February to April 1...

  3. Modular genetic regulatory networks increase organization during pattern formation.

    Science.gov (United States)

    Mohamadlou, Hamid; Podgorski, Gregory J; Flann, Nicholas S

    2016-08-01

    Studies have shown that genetic regulatory networks (GRNs) consist of modules that are densely connected subnetworks that function quasi-autonomously. Modules may be recognized motifs that comprise of two or three genes with particular regulatory functions and connectivity or be purely structural and identified through connection density. It is unclear what evolutionary and developmental advantages modular structure and in particular motifs provide that have led to this enrichment. This study seeks to understand how modules within developmental GRNs influence the complexity of multicellular patterns that emerge from the dynamics of the regulatory networks. We apply an algorithmic complexity to measure the organization of the patterns. A computational study was performed by creating Boolean intracellular networks within a simulated epithelial field of embryonic cells, where each cell contains the same network and communicates with adjacent cells using contact-mediated signaling. Intracellular networks with random connectivity were compared to those with modular connectivity and with motifs. Results show that modularity effects network dynamics and pattern organization significantly. In particular: (1) modular connectivity alone increases complexity in network dynamics and patterns; (2) bistable switch motifs simplify both the pattern and network dynamics; (3) all other motifs with feedback loops increase multicellular pattern complexity while simplifying the network dynamics; (4) negative feedback loops affect the dynamics complexity more significantly than positive feedback loops.

  4. Formation Pattern Based on Modified Cell Decomposition Algorithm

    Directory of Open Access Journals (Sweden)

    Iswanto Iswanto

    2017-06-01

    Full Text Available The purpose of this paper is to present the shortest path algorithm for Quadrotor to make a formation quickly and avoid obstacles in an unknown area. There are three algorithms proposed in this paper namely fuzzy, cell decomposition, and potential field algorithms. Cell decomposition algorithm is an algorithm derived from graph theory used to create maps of robot formations. Fuzzy algorithm is an artificial intelligence control algorithm used for robot navigation. The merger of these two algorithms are not able to form an optimum formation because some Quadrotors which have been hovering should wait for the other Quadrotors which are unable to find the shortest distance to reach the formation quickly. The problem is that the longer time the multi Quadrotors take to make a formation, the more energy they use. It can be overcome by adding potential field algorithm. The algorithm is used to give values of weight to the path planning taken by the Quadrotors. The proposed algorithms have shown that multi Quadrotors can quickly make a formation because they are able to avoid various obstacles and find the shortest path so that the time required to get to the goal position is fast.

  5. Genetic analysis of blood vessel formation role of endothelial versus smooth muscle cells.

    Science.gov (United States)

    Carmeliet, P; Collen, D

    1997-11-01

    Formation of new blood vessels is vital during embryogenesis, essential for reproduction and wound healing during adulthood, and required to rescue tissue during ischemia. Neovascularization may, however, also contribute to the pathogenesis of several disorders, including tumorigenesis, diabetic vasculopathy, and chronic inflammation. Initially, blood vessels form as endothelium-lined channels by in situ differentiation of endothelial cells. Subsequently, they sprout and remodel into a highly organized and interconnected vascular network. During further maturation of the blood vessels, a sheet of primitive vascular smooth muscle cells surrounds the endothelium-lined channels, which controls endothelial cell function and provides structural support. Recent molecular analyses have identified candidate molecules that affect these processes. Their in vivo role has been further established by targeted gene manipulation in transgenic mice. This review highlights recent developments in the genetic analysis of blood vessel formation, as deduced from analysis of gene-inactivated mice. (Trends Cardiovasc Med 1997;7:271-281). © 1997, Elsevier Science Inc.

  6. Precocious locomotor behavior begins in the egg: development of leg muscle patterns for stepping in the chick.

    Directory of Open Access Journals (Sweden)

    Young U Ryu

    Full Text Available BACKGROUND: The chicken is capable of adaptive locomotor behavior within hours after hatching, yet little is known of the processes leading to this precocious skill. During the final week of incubation, chick embryos produce distinct repetitive limb movements that until recently had not been investigated. In this study we examined the leg muscle patterns at 3 time points as development of these spontaneous movements unfolds to determine if they exhibit attributes of locomotion reported in hatchlings. We also sought to determine whether the deeply flexed posture and movement constraint imposed by the shell wall modulate the muscle patterns. METHODOLOGY/PRINCIPAL FINDINGS: Synchronized electromyograms for leg muscles, force and video were recorded continuously from embryos while in their naturally flexed posture at embryonic day (E 15, E18 and E20. We tested for effects of leg posture and constraint by removing shell wall anterior to the foot. Results indicated that by E18, burst onset time distinguished leg muscle synergists from antagonists across a 10-fold range in burst frequencies (1-10 Hz, and knee extensors from ankle extensors in patterns comparable to locomotion at hatching. However, burst durations did not scale with step cycle duration in any of the muscles recorded. Despite substantially larger leg movements after shell removal, the knee extensor was the only muscle to vary its activity, and extensor muscles often failed to participate. To further clarify if the repetitive movements are likely locomotor-related, we examined bilateral coordination of ankle muscles during repetitive movements at E20. In all cases ankle muscles exhibited a bias for left/right alternation. CONCLUSIONS/SIGNIFICANCE: Collectively, the findings lead us to conclude that the repetitive leg movements in late stage embryos are locomotor-related and a fundamental link in the establishment of precocious locomotor skill. The potential importance of differences

  7. LAWS OF FORMATION MOVEMENT PATTERNS MANAGEMENT BODY IN PHASE OF FLIGHT IN ATHLETES

    Directory of Open Access Journals (Sweden)

    A. V. Razuvanova

    2016-01-01

    Full Text Available Materials and methods. Regularities of movement patterns in the body control the flight phase of the athletes on the example of the long jump were studied by methods of Motion Tracking and electromyography. The findings suggest that a significant difference of motor stereotypes underlying the performance of motor actions – the long jump – in different skill athletes.Results. In the initial phase (phase jumping differences between the groups are small - repulsion athletes perform in a similar manner, a core group of athletes with a more efficient use of the reserve of the work of the knee. The nature of the work the leg muscles in athletes of both groups in this phase is also not different. However, the further execution of motor actions in athletes of both groups occurs in different ways. Athletes of the control group did not perform virtually control the body in flight phase. This is evidenced primarily high tone muscles in the arms, back and neck throughout the flight phase. Movements are performed only in the knee and hip joints, and already in the phase of “hang-up” – the highest point of the flight path - these movements have focused on the preparation for landing.Conclusions. Athletes of the main group in the flight phase involve the full range of movements - flexion and extension are performed as in the shoulder and elbow joints, as well as in the neck and spine joints. All these movements are designed to increase the range of jumps - this contributes to the removal of the legs forward, and giving the body angular acceleration by the movement of legs and head. Preparation for landing is made directly before contact with the surface, but the very nature of the phase of flight allows the athlete to use the inertia of motion of the body as much as possible to lengthen the jump and thus facilitate shock absorption and retention of balance upon landing.Formation movement patterns in the body control the flight phase of the athletes

  8. Biological pattern formation: from basic mechanisms to complex structures

    Science.gov (United States)

    Koch, A. J.; Meinhardt, H.

    1994-10-01

    The reliable development of highly complex organisms is an intriguing and fascinating problem. The genetic material is, as a rule, the same in each cell of an organism. How then do cells, under the influence of their common genes, produce spatial patterns? Simple models are discussed that describe the generation of patterns out of an initially nearly homogeneous state. They are based on nonlinear interactions of at least two chemicals and on their diffusion. The concepts of local autocatalysis and of long-range inhibition play a fundamental role. Numerical simulations show that the models account for many basic biological observations such as the regeneration of a pattern after excision of tissue or the production of regular (or nearly regular) arrays of organs during (or after) completion of growth. Very complex patterns can be generated in a reproducible way by hierarchical coupling of several such elementary reactions. Applications to animal coats and to the generation of polygonally shaped patterns are provided. It is further shown how to generate a strictly periodic pattern of units that themselves exhibit a complex and polar fine structure. This is illustrated by two examples: the assembly of photoreceptor cells in the eye of Drosophila and the positioning of leaves and axillary buds in a growing shoot. In both cases, the substructures have to achieve an internal polarity under the influence of some primary pattern-forming system existing in the fly's eye or in the plant. The fact that similar models can describe essential steps in organisms as distantly related as animals and plants suggests that they reveal some universal mechanisms.

  9. Development-related expression patterns of protein-coding and miRNA genes involved in porcine muscle growth.

    Science.gov (United States)

    Wang, F J; Jin, L; Guo, Y Q; Liu, R; He, M N; Li, M Z; Li, X W

    2014-11-27

    Muscle growth and development is associated with remarkable changes in protein-coding and microRNA (miRNA) gene expression. To determine the expression patterns of genes and miRNAs related to muscle growth and development, we measured the expression levels of 25 protein-coding and 16 miRNA genes in skeletal and cardiac muscles throughout 5 developmental stages by quantitative reverse transcription-polymerase chain reaction. The Short Time-Series Expression Miner (STEM) software clustering results showed that growth-related genes were downregulated at all developmental stages in both the psoas major and longissimus dorsi muscles, indicating their involvement in early developmental stages. Furthermore, genes related to muscle atrophy, such as forkhead box 1 and muscle ring finger, showed unregulated expression with increasing age, suggesting a decrease in protein synthesis during the later stages of skeletal muscle development. We found that development of the cardiac muscle was a complex process in which growth-related genes were highly expressed during embryonic development, but they did not show uniform postnatal expression patterns. Moreover, the expression level of miR-499, which enhances the expression of the β-myosin heavy chain, was significantly different in the psoas major and longissimus dorsi muscles, suggesting the involvement of miR-499 in the determination of skeletal muscle fiber types. We also performed correlation analyses of messenger RNA and miRNA expression. We found negative relationships between miR-486 and forkhead box 1, and miR-133a and serum response factor at all developmental stages, suggesting that forkhead box 1 and serum response factor are potential targets of miR-486 and miR-133a, respectively.

  10. CDS Simulation and Pattern Formation of Phase Separation

    Institute of Scientific and Technical Information of China (English)

    ZhangjiLIU; MenCHENG; 等

    1998-01-01

    Several properties of the generation and evolution of phase separating patterns for binary material studied by CDS model are proposed.The main conclusions are(1) for alloys spinodal decomposition,the conceptions of “macro-pattern” and “micropattern” are posed by “black-and-white graph”and “gray-scale graph” respectively.We find that though the four forms of map f that represent the self-evolution of order parameter in a cell (lattice)are similar to each other in “macro-pattern”,there are evident differences in their micro-pattern,e.g.,some different fine netted sturctures in the black domain and the white domain are found by the micro-pattern.so that distinct mechanical and physical behaviors shall be obtained.(2) If the two constituteons of block copolymers are not symmetric (i.e.r≠0.5),a pattern called “grain-strip cross pattern is discovered,is the 0.43

  11. Eccentric muscle damage has variable effects on motor unit recruitment thresholds and discharge patterns in elbow flexor muscles.

    Science.gov (United States)

    Dartnall, Tamara J; Rogasch, Nigel C; Nordstrom, Michael A; Semmler, John G

    2009-07-01

    The purpose of this study was to determine the effect of eccentric muscle damage on recruitment threshold force and repetitive discharge properties of low-threshold motor units. Ten subjects performed four tasks involving isometric contraction of elbow flexors while electromyographic (EMG) data were recorded from human biceps brachii and brachialis muscles. Tasks were 1) maximum voluntary contraction (MVC); 2) constant-force contraction at various submaximal targets; 3) motor unit recruitment threshold task; and 4) minimum motor unit discharge rate task. These tasks were performed on three separate days before, immediately after, and 24 h after eccentric exercise of elbow flexor muscles. MVC force declined (42%) immediately after exercise and remained depressed (29%) 24 h later, indicative of muscle damage. Mean motor unit recruitment threshold for biceps brachii was 8.4+/-4.2% MVC, (n=34) before eccentric exercise, and was reduced by 41% (5.0+/-3.0% MVC, n=34) immediately after and by 39% (5.2+/-2.5% MVC, n=34) 24 h after exercise. No significant changes in motor unit recruitment threshold were observed in the brachialis muscle. However, for the minimum tonic discharge rate task, motor units in both muscles discharged 11% faster (10.8+/-2.0 vs. 9.7+/-1.7 Hz) immediately after (n=29) exercise compared with that before (n=32). The minimum discharge rate variability was greater in brachialis muscle immediately after exercise (13.8+/-3.1%) compared with that before (11.9+/-3.1%) and 24 h after exercise (11.7+/-2.4%). No significant changes in minimum discharge rate variability were observed in the biceps brachii motor units after exercise. These results indicate that muscle damage from eccentric exercise alters motor unit recruitment thresholds for >or=24 h, but the effect is not the same in the different elbow flexor muscles.

  12. A Broad Dynamical Model for Pattern Formation by Lateral Inhibition

    CERN Document Server

    Arcak, Murat

    2012-01-01

    Many patterning events in multi-cellular organisms rely on cell-to-cell contact signaling, such as the Notch pathway in metazoans. A particularly interesting phenomenon in this form of communication is lateral inhibition where a cell that adopts a particular fate inhibits its immediate neighbors from doing the same. Dynamical models are of great interest for understanding the circuit topologies involved in lateral inhibition and for predicting the associated patterns. Several simplified models have been employed for Notch signalling pathways in the literature. The objective of this paper is to present an abstract dynamical model that captures the essential features of lateral inhibition and to demonstrate with dynamical systems techniques that these features indeed lead to patterning.

  13. Mathematical study on robust tissue pattern formation in growing epididymal tubule.

    Science.gov (United States)

    Hirashima, Tsuyoshi

    2016-10-21

    Tissue pattern formation during development is a reproducible morphogenetic process organized by a series of kinetic cellular activities, leading to the building of functional and stable organs. Recent studies focusing on mechanical aspects have revealed physical mechanisms on how the cellular activities contribute to the formation of reproducible tissue patterns; however, the understanding for what factors achieve the reproducibility of such patterning and how it occurs is far from complete. Here, I focus on a tube pattern formation during murine epididymal development, and show that two factors influencing physical design for the patterning, the proliferative zone within the tubule and the viscosity of tissues surrounding to the tubule, control the reproducibility of epididymal tubule pattern, using a mathematical model based on experimental data. Extensive numerical simulation of the simple mathematical model revealed that a spatially localized proliferative zone within the tubule, observed in experiments, results in more reproducible tubule pattern. Moreover, I found that the viscosity of tissues surrounding to the tubule imposes a trade-off regarding pattern reproducibility and spatial accuracy relating to the region where the tubule pattern is formed. This indicates an existence of optimality in material properties of tissues for the robust patterning of epididymal tubule. The results obtained by numerical analysis based on experimental observations provide a general insight on how physical design realizes robust tissue pattern formation.

  14. Mathematical aspects of pattern formation in biological systems

    CERN Document Server

    Wei, Juncheng

    2013-01-01

    This monograph is concerned with the mathematical analysis of patterns which are encountered in biological systems. It summarises, expands and relates results obtained in the field during the last fifteen years. It also links the results to biological applications and highlights their relevance to phenomena in nature. Of particular concern are large-amplitude patterns far from equilibrium in biologically relevant models.The approach adopted in the monograph is based on the following paradigms:• Examine the existence of spiky steady states in reaction-diffusion systems and select as observabl

  15. Viscoelasticity and pattern formations in stock market indices

    Science.gov (United States)

    Gündüz, Güngör; Gündüz, Aydın

    2017-06-01

    The viscoelastic and thermodynamic properties of four stock indices, namely, DJI, Nasdaq-100, Nasdaq-Composite, and S&P were analyzed for a period of 30 years from 1986 to 2015. The asset values (or index) can be placed into Aristotelian `potentiality-actuality' framework by using scattering diagram. Thus, the index values can be transformed into vectorial forms in a scattering diagram, and each vector can be split into its horizontal and vertical components. According to viscoelastic theory, the horizontal component represents the conservative, and the vertical component represents the dissipative behavior. The related storage and the loss modulus of these components are determined and then work-like and heat-like terms are calculated. It is found that the change of storage and loss modulus with Wiener noise (W) exhibit interesting patterns. The loss modulus shows a featherlike pattern, whereas the storage modulus shows figurative man-like pattern. These patterns are formed due to branchings in the system and imply that stock indices do have a kind of `fine-order' which can be detected when the change of modulus values are plotted with respect to Wiener noise. In theoretical calculations it is shown that the tips of the featherlike patterns stay at negative W values, but get closer to W = 0 as the drift in the system increases. The shift of the tip point from W = 0 indicates that the price change involves higher number of positive Wiener number corrections than the negative Wiener. The work-like and heat-like terms also exhibit patterns but with different appearance than modulus patterns. The decisional changes of people are reflected as the arrows in the scattering diagram and the propagation path of these vectors resemble the path of crack propagation. The distribution of the angle between two subsequent vectors shows a peak at 90°, indicating that the path mostly obeys the crack path occurring in hard objects. Entropy mimics the Wiener noise in the evolution

  16. Distribution patterns and predilection muscles of Trichinella zimbabwensis larvae in experimentally infected Nile crocodiles (Crocodylus niloticus Laurenti).

    Science.gov (United States)

    La Grange, Louis J; Mukaratirwa, Samson

    2014-02-21

    No controlled studies have been conducted to determine the predilection muscles of Trichinella zimbabwensis larvae in Nile crocodiles (Crocodylus niloticus) or the influence of infection intensity on the distribution of the larvae in crocodiles. The distribution of larvae in muscles of naturally infected Nile crocodiles and experimentally infected caimans (Caiman crocodilus) and varans (Varanus exanthematicus) have been reported in literature. To determine the distribution patterns of T. zimbabwensis larvae and predilection muscles, 15 crocodiles were randomly divided into three cohorts of five animals each, representing high infection (642 larvae/kg of bodyweight average), medium infection (414 larvae/kg of bodyweight average) and low infection (134 larvae/kg of bodyweight average) cohorts. In the high infection cohort, high percentages of larvae were observed in the triceps muscles (26%) and hind limb muscles (13%). In the medium infection cohort, high percentages of larvae were found in the triceps muscles (50%), sternomastoid (18%) and hind limb muscles (13%). In the low infection cohort, larvae were mainly found in the intercostal muscles (36%), longissimus complex (27%), forelimb muscles (20%) and hind limb muscles (10%). Predilection muscles in the high and medium infection cohorts were similar to those reported in naturally infected crocodiles despite changes in infection intensity. The high infection cohort had significantly higher numbers of larvae in the sternomastoid, triceps, intercostal, longissimus complex, external tibial flexor, longissimus caudalis and caudal femoral muscles (p crocodiles. Results from this study show that, in Nile crocodiles, larvae of T. zimbabwensis appear first to invade predilection muscles closest to their release site in the small intestine before occupying those muscles situated further away. The recommendation for the use of masseter, pterygoid and intercostal muscles as sampling sites for the detection of T. zimbabwensis

  17. Difference in muscle activation patterns during high-speed versus standard-speed yoga: A randomized sequence crossover study.

    Science.gov (United States)

    Potiaumpai, Melanie; Martins, Maria Carolina Massoni; Wong, Claudia; Desai, Trusha; Rodriguez, Roberto; Mooney, Kiersten; Signorile, Joseph F

    2017-02-01

    To compare the difference in muscle activation between high-speed yoga and standard-speed yoga and to compare muscle activation of the transitions between poses and the held phases of a yoga pose. Randomized sequence crossover trial SETTING: A laboratory of neuromuscular research and active aging Interventions: Eight minutes of continuous Sun Salutation B was performed, at a high speed versus a standard-speed, separately. Electromyography was used to quantify normalized muscle activation patterns of eight upper and lower body muscles (pectoralis major, medial deltoids, lateral head of the triceps, middle fibers of the trapezius, vastus medialis, medial gastrocnemius, thoracic extensor spinae, and external obliques) during the high-speed and standard-speed yoga protocols. Difference in normalized muscle activation between high-speed yoga and standard-speed yoga. Normalized muscle activity signals were significantly higher in all eight muscles during the transition phases of poses compared to the held phases (pyoga across the entire session. Our results show that transitions from one held phase of a pose to another produces higher normalized muscle activity than the held phases of the poses and that overall activity is greater during highspeed yoga than standard-speed yoga. Therefore, the transition speed and associated number of poses should be considered when targeting specific improvements in performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Pattern formation in the bistable Gray-Scott model

    DEFF Research Database (Denmark)

    Mazin, W.; Rasmussen, K.E.; Mosekilde, Erik

    1996-01-01

    The paper presents a computer simulation study of a variety of far-from-equilibrium phenomena that can arise in a bistable chemical reaction-diffusion system which also displays Turing and Hopf instabilities. The Turing bifurcation curve and the wave number for the patterns of maximum linear grow...

  19. Pattern formation in the wake of triggered pushed fronts

    Science.gov (United States)

    Goh, Ryan; Scheel, Arnd

    2016-08-01

    Pattern-forming fronts are often controlled by an external stimulus which progresses through a stable medium at a fixed speed, rendering it unstable in its wake. By controlling the speed of excitation, such stimuli, or ‘triggers’, can mediate pattern forming fronts which freely invade an unstable equilibrium and control which pattern is selected. In this work, we analytically and numerically study when the trigger perturbs an oscillatory pushed free front. In such a situation, the resulting patterned front, which we call a pushed trigger front, exhibits a variety of phenomenon, including snaking, non-monotonic wave-number selection, and hysteresis. Assuming the existence of a generic oscillatory pushed free front, we use heteroclinic bifurcation techniques to prove the existence of trigger fronts in an abstract setting motivated by the spatial dynamics approach. We then derive a leading order expansion for the selected wave-number in terms of the trigger speed. Furthermore, we show that such a bifurcation curve is governed by the difference of certain strong-stable and weakly-stable spatial eigenvalues associated with the decay of the free pushed front. We also study prototypical examples of these phenomena in the cubic-quintic complex Ginzburg Landau equation and a modified Cahn-Hilliard equation.

  20. Size segregated ring pattern formation in particle impactors

    Science.gov (United States)

    Saylor, J. R.; Fredericks, S. A.

    2016-11-01

    Typical particle impactors consist of a nozzle that directs a particle laden flow onto a plate, and is designed to capture particles greater than a cutoff diameter. Connected in series as a cascade, with each impactor designed to have a progressively smaller cutoff diameter, the particle size distribution can be measured. Typical impactors utilize a nozzle-to-plate distance S that is on the order of one nozzle diameter W, S / W 1 , and give a nominally Gaussian particle deposition pattern on the plate. We explored conditions where S / W < < 1 and observed deposition patterns consisting of very fine rings. Moreover, we found that the ring diameter increased with decreasing particle diameter and the ring thickness increased with particle diameter. These results suggest a potential method for sizing particles by using the mature technology of impactors in a different way. Potential mechanisms for how these ring patterns are formed will be discussed. We note that prior studies have observed conditions where particle deposition patterns exhibited "halos". These halos appear less distinct than the rings we have observed, and it is unclear whether they are related.

  1. Fluctuation-Induced Pattern Formation in a Surface Reaction

    DEFF Research Database (Denmark)

    Starke, Jens; Reichert, Christian; Eiswirth, Markus

    2006-01-01

    Spontaneous nucleation, pulse formation, and propagation failure have been observed experimentally in CO oxidation on Pt(110) at intermediate pressures ($\\approx 10^{-2}$mbar). This phenomenon can be reproduced with a stochastic model which includes temperature effects. Nucleation occurs randomly...

  2. Spontaneous tunable Turing pattern formation for coherent high-power THz radiation

    CERN Document Server

    Huang, Shu-Wei; Yang, Shang-Hua; Yu, Mingbin; Kwong, Dim-Lee; Zelevinsky, T; Jarrahi, Mona; Wong, Chee Wei

    2016-01-01

    The spontaneous breaking of symmetry and homogeneity through dissipative pattern formation is a fundamental question in developmental biology, molecular biochemistry, mathematics and nonlinear physics. Self-organized patterns arise in nature, such as pigmentation in animals, tree branching fractals, Prigogine non-equilibrium chemical bifurcations, and are postulated by Turing to occur from diffusion-reaction driven instabilities. In spite of the spontaneous nature, these threshold-dependent patterns - when formed - can potentially be remarkably robust in the presence of noise. Here we report the spontaneous Turing pattern formation in chip-scale nonlinear oscillators, developing a precision frequency comb in the solid-state. The stationary Turing pattern is discretely tunable across 430 GHz on a THz carrier, with a sideband non-uniformity measured down to 1 part in 1.5x10^15. Local mode hybridizations in the nonlinear ring oscillator seeds the coherent pattern formation and phase matching, to obtain a record ...

  3. Quantum properties of transverse pattern formation in second-harmonic generation

    DEFF Research Database (Denmark)

    Bache, Morten; Scotto, P.; Zambrini, R.;

    2002-01-01

    We investigate the spatial quantum noise properties of the one-dimensional transverse pattern formation instability in intracavity second-harmonic generation. The Q representation of a quasi-probability distribution is implemented in terms of nonlinear stochastic Langevin equations. We study...... these equations through extensive numerical simulations and analytically in the linearized limit. Our study, made below and above the threshold of pattern formation, is guided by a microscopic scheme of photon interaction underlying pattern formation in second-harmonic generation. Close to the threshold...

  4. Magnolol inhibits migration of vascular smooth muscle cells via cytoskeletal remodeling pathway to attenuate neointima formation

    Energy Technology Data Exchange (ETDEWEB)

    Karki, Rajendra [Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City (United States); Department of Oriental Medicine Resources, Mokpo National University (Korea, Republic of); Kim, Seong-Bin [Jeollanamdo Development Institute for Korean Traditional Medicine, Jangheung gun, Jeollanamdo (Korea, Republic of); Kim, Dong-Wook, E-mail: dbkim@mokpo.ac.kr [Department of Oriental Medicine Resources, Mokpo National University (Korea, Republic of)

    2013-12-10

    Background: Increased proliferation and migration of vascular smooth muscle cells (VSMCs) contribute importantly to the formation of both atherosclerotic and restenotic lesions. The objective of this study was to investigate the effect of magnolol on VSMC migration. Methods: The proteolytic activity of matrix metalloproteinases (MMPs) in tumor necrosis factor alpha (TNF-α) stimulated VSMCs was performed by gelatin zymography. VSMC migration was assessed by wound healing and Boyden chamber methods. Collagen induced VSMC adhesion was determined by spectrofluorimeter and stress fibers formation was evaluated by fluorescence microscope. The expression of signaling molecules involved in stress fibers formation was determined by western blot. The phosphorylation of myosin light chain (MLC20) was determined by urea-glycerol polyacrylamide gel electrophoresis. Immunohistochemistry was performed to determine the expression of β1-integrin and collagen type I in the injured carotid arteries of rats on day 35 after vascular injury. Results: VSMC migration was strongly inhibited by magnolol without affecting MMPs expression. Also, magnolol inhibited β1-integrin expression, FAK phosphorylation and RhoA and Cdc42 activation to inhibit the collagen induced stress fibers formation. Moreover, magnolol inhibited the phosphorylation of MLC20. Our in vivo results showed that magnolol inhibited β1-integrin expression, collagen type I deposition and FAK phosphorylation in injured carotid arteries without affecting MMP-2 activity. Conclusions: Magnolol inhibited VSMC migration via inhibition of cytoskeletal remodeling pathway to attenuate neointima formation. General significance: This study provides a rationale for further evaluation of magnolol for the management of atherosclerosis and restenosis. - Highlights: • Magnolol strongly inhibited migration of VSMCs. • Magnolol inhibited stress fibers formation. • MLC20 phosphorylation was also inhibited by magnolol. • Anti

  5. Myostatin shows a specific expression pattern in pig skeletal and extraocular muscles during pre- and post-natal growth.

    Science.gov (United States)

    Patruno, Marco; Caliaro, Francesca; Maccatrozzo, Lisa; Sacchetto, Roberta; Martinello, Tiziana; Toniolo, Luana; Reggiani, Carlo; Mascarello, Francesco

    2008-02-01

    Myogenesis is driven by an extraordinary array of cellular signals that follow a common expression pattern among different animal phyla. Myostatin (mstn) is a secreted growth factor that plays a pivotal role in skeletal muscle mass regulation. The aim of the present study was to investigate mstn expression in a large mammal (the pig) in order to ascertain whether distinct expression changes of this factor might be linked to the fiber-type composition of the muscle examined and/or to specific developmental stages. To assess the expression pattern of mstn in relation to myogenic proliferative (Pax7 and MyoD) and differentiative (myogenin) markers, we evaluated muscles with different myosin heavy-chain compositions sampled during pre- and post-natal development and on myogenic cells isolated from the same muscles. Skeletal muscles showed higher levels of mRNA for mstn and all other genes examined during fetal development than after birth. The wide distribution of mstn was also confirmed by immunohistochemistry experiments supporting evidence for cytoplasmic staining in early fetal periods as well as the localization in type 1 fibers at the end of the gestation period. Extraocular muscles, in contrast, did not exhibit decreasing mRNA levels for mstn or other genes even in adult samples and expressed higher levels of both mstn mRNA and protein compared with skeletal muscles. Experiments carried out on myogenic cells showed that mstn mRNA levels decreased when myoblasts entered the differentiation program and that cells isolated at early post-natal stages maintained a high level of Pax7 expression. Our results showed that mstn had a specific expression pattern whose variations depended on the muscle type examined, thus supporting the hypothesis that at birth, porcine myogenic cells continue to be influenced by hyperplastic/proliferative mechanisms.

  6. Cricket fast bowling workload patterns as risk factors for tendon, muscle, bone and joint injuries.

    Science.gov (United States)

    Orchard, John W; Blanch, Peter; Paoloni, Justin; Kountouris, Alex; Sims, Kevin; Orchard, Jessica J; Brukner, Peter

    2015-08-01

    To assess workload-related risk factors for injuries to particular tissue types in cricket fast bowlers. 235 fast bowlers who bowled in 14600 player innings over a period of 15 years were followed in a prospective cohort risk factor study to compare overs bowled in each match (including preceding workload patterns) and injury risk in the 3-4 weeks subsequent to the match. Injuries were categorised according to the affected tissue type as either: bone stress, tendon injuries, muscle strain or joint injuries. Workload risk factors were examined using binomial logistic regression multivariate analysis, with a forward stepwise procedure requiring a significance of injuries, but high medium term (3-month workload) was protective. For bone stress injuries, high medium term workload and low career workload were risk factors. For joint injuries, high previous season and career workload were risk factors. There was little relationship between muscle injury and workload although high previous season workload was slightly protective. The level of injury risk for some tissue types varies in response to preceding fast bowling workload, with tendon injuries most affected by workload patterns. Workload planning may need to be individualised, depending on individual susceptibility to various injury types. This study supports the theory that tendons are at lowest risk with consistent workloads and susceptible to injury with sudden upgrades in workload. Gradual upgrades are recommended, particularly at the start of a bowler's career to reduce the risk of bone stress injury. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  7. Direct numerical simulation of pattern formation in subaqueous sediment

    CERN Document Server

    Kidanemariam, Aman G

    2014-01-01

    We present results of direct numerical simulation of incompressible fluid flow over a thick bed of mobile, spherically-shaped particles. The algorithm is based upon the immersed boundary technique for fluid-solid coupling and uses a soft-sphere model for the solid-solid contact. Two parameter points in the laminar flow regime are chosen, leading to the emergence of sediment patterns classified as `small dunes', while one case under turbulent flow conditions leads to `vortex dunes' with significant flow separation on the lee side. Wavelength, amplitude and propagation speed of the patterns extracted from the spanwise-averaged fluid-bed interface are found to be consistent with available experimental data. The particle transport rates are well represented by available empirical models for flow over a plane sediment bed in both the laminar and the turbulent regimes.

  8. Perspective: network-guided pattern formation of neural dynamics

    OpenAIRE

    Hütt, Marc-Thorsten; Kaiser, Marcus; Claus C Hilgetag

    2014-01-01

    The understanding of neural activity patterns is fundamentally linked to an understanding of how the brain's network architecture shapes dynamical processes. Established approaches rely mostly on deviations of a given network from certain classes of random graphs. Hypotheses about the supposed role of prominent topological features (for instance, the roles of modularity, network motifs or hierarchical network organization) are derived from these deviations. An alternative strategy could be to...

  9. Dynamic array generation and pattern formation for optical tweezers

    DEFF Research Database (Denmark)

    Mogensen, P.C.; Glückstad, J.

    2000-01-01

    The generalised phase contrast approach is used for the generation of optical arrays of arbitrary beam shape, suitable for applications in optical tweezers for the manipulation of biological specimens. This approach offers numerous advantages over current techniques involving the use of computer......-generated holograms or diffractive optical elements. We demonstrate a low-loss system for generating intensity patterns suitable for the trapping and manipulation of small particles or specimens....

  10. Probabilistic Analysis of Pattern Formation in Monotonic Self-Assembly.

    Science.gov (United States)

    Moore, Tyler G; Garzon, Max H; Deaton, Russell J

    2015-01-01

    Inspired by biological systems, self-assembly aims to construct complex structures. It functions through piece-wise, local interactions among component parts and has the potential to produce novel materials and devices at the nanoscale. Algorithmic self-assembly models the product of self-assembly as the output of some computational process, and attempts to control the process of assembly algorithmically. Though providing fundamental insights, these computational models have yet to fully account for the randomness that is inherent in experimental realizations, which tend to be based on trial and error methods. In order to develop a method of analysis that addresses experimental parameters, such as error and yield, this work focuses on the capability of assembly systems to produce a pre-determined set of target patterns, either accurately or perhaps only approximately. Self-assembly systems that assemble patterns that are similar to the targets in a significant percentage are "strong" assemblers. In addition, assemblers should predominantly produce target patterns, with a small percentage of errors or junk. These definitions approximate notions of yield and purity in chemistry and manufacturing. By combining these definitions, a criterion for efficient assembly is developed that can be used to compare the ability of different assembly systems to produce a given target set. Efficiency is a composite measure of the accuracy and purity of an assembler. Typical examples in algorithmic assembly are assessed in the context of these metrics. In addition to validating the method, they also provide some insight that might be used to guide experimentation. Finally, some general results are established that, for efficient assembly, imply that every target pattern is guaranteed to be assembled with a minimum common positive probability, regardless of its size, and that a trichotomy exists to characterize the global behavior of typical efficient, monotonic self-assembly systems

  11. Probabilistic Analysis of Pattern Formation in Monotonic Self-Assembly.

    Directory of Open Access Journals (Sweden)

    Tyler G Moore

    Full Text Available Inspired by biological systems, self-assembly aims to construct complex structures. It functions through piece-wise, local interactions among component parts and has the potential to produce novel materials and devices at the nanoscale. Algorithmic self-assembly models the product of self-assembly as the output of some computational process, and attempts to control the process of assembly algorithmically. Though providing fundamental insights, these computational models have yet to fully account for the randomness that is inherent in experimental realizations, which tend to be based on trial and error methods. In order to develop a method of analysis that addresses experimental parameters, such as error and yield, this work focuses on the capability of assembly systems to produce a pre-determined set of target patterns, either accurately or perhaps only approximately. Self-assembly systems that assemble patterns that are similar to the targets in a significant percentage are "strong" assemblers. In addition, assemblers should predominantly produce target patterns, with a small percentage of errors or junk. These definitions approximate notions of yield and purity in chemistry and manufacturing. By combining these definitions, a criterion for efficient assembly is developed that can be used to compare the ability of different assembly systems to produce a given target set. Efficiency is a composite measure of the accuracy and purity of an assembler. Typical examples in algorithmic assembly are assessed in the context of these metrics. In addition to validating the method, they also provide some insight that might be used to guide experimentation. Finally, some general results are established that, for efficient assembly, imply that every target pattern is guaranteed to be assembled with a minimum common positive probability, regardless of its size, and that a trichotomy exists to characterize the global behavior of typical efficient, monotonic

  12. Pattern Formation in Predator-Prey Model with Delay and Cross Diffusion

    Directory of Open Access Journals (Sweden)

    Xinze Lian

    2013-01-01

    Full Text Available We consider the effect of time delay and cross diffusion on the dynamics of a modified Leslie-Gower predator-prey model incorporating a prey refuge. Based on the stability analysis, we demonstrate that delayed feedback may generate Hopf and Turing instability under some conditions, resulting in spatial patterns. One of the most interesting findings is that the model exhibits complex pattern replication: the model dynamics exhibits a delay and diffusion controlled formation growth not only to spots, stripes, and holes, but also to spiral pattern self-replication. The results indicate that time delay and cross diffusion play important roles in pattern formation.

  13. Dewetting-mediated pattern formation in nanoparticle assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Stannard, Andrew, E-mail: andrew.stannard@nottingham.ac.uk [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2011-03-02

    The deposition of nanoparticles from solution onto solid substrates is a diverse subfield of current nanoscience research. Complex physical and chemical processes underpin the self-assembly and self-organization of colloidal nanoparticles at two-phase (solid-liquid, liquid-air) interfaces and three-phase (solid-liquid-air) contact lines. This review discusses key recent advances made in the understanding of nonequilibrium dewetting processes of nanoparticle-containing solutions, detailing how such an apparently simple experimental system can give rise to such a strikingly varied palette of two-dimensional self-organized nanoparticle array morphologies. Patterns discussed include worm-like domains, cellular networks, microscale rings, and fractal-like fingering structures. There remain many unresolved issues regarding the role of the solvent dewetting dynamics in assembly processes of this type, with a significant focus on how dewetting can be coerced to produce nanoparticle arrays with desirable characteristics such as long-range order. In addition to these topics, methods developed to control nanofluid dewetting through routes such as confining the geometries of drying solutions, depositing onto pre-patterned heterogeneous substrates, and post-dewetting pattern evolution via local or global manipulation are covered. (topical review)

  14. Nanoparticles dynamics on a surface: fractal pattern formation and fragmentation

    DEFF Research Database (Denmark)

    Dick, Veronika V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2010-01-01

    In this paper we review our recent results on the formation and the post-growth relaxation processes of nanofractals on surface. For this study we developed a method which describes the internal dynamics of particles in a fractal and accounts for their diffusion and detachment. We demonstrate...... that these kinetic processes determine the final shape of the islands on surface after post-growth relaxation. We consider different scenarios of fractal relaxation and analyze the time evolution of the island's morphology....

  15. Nanoparticles dynamics on a surface: fractal pattern formation and fragmentation

    DEFF Research Database (Denmark)

    Dick, Veronika V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2010-01-01

    In this paper we review our recent results on the formation and the post-growth relaxation processes of nanofractals on surface. For this study we developed a method which describes the internal dynamics of particles in a fractal and accounts for their diffusion and detachment. We demonstrate...... that these kinetic processes determine the final shape of the islands on surface after post-growth relaxation. We consider different scenarios of fractal relaxation and analyze the time evolution of the island's morphology....

  16. Influence of phase separation for surfactant driven pattern formation during ion beam erosion

    Energy Technology Data Exchange (ETDEWEB)

    Hofsaess, Hans; Zhang, Kun; Vetter, Ulrich; Bobes, Omar; Pape, Andre; Gehrke, Hans-Gregor; Broetzmann, Marc [II. Physikalisches Institut, Goettingen Univ. (Germany)

    2012-07-01

    We will present results on metal surfactant driven self-organized pattern formation on surfaces by ion beam erosion, with a focus on the role of phase separation for the initial steps of pattern formation. Si substrates were irradiated with 5 keV Xe ions at normal incidence and ion fluences up to 5.10{sup 17} Xe/cm{sup 2} under continuous deposition of surfactant atoms. In the absence of such surfactants uniform flat surfaces are obtained, while in the presence of Fe and Mo surfactants pronounced patterns like dots, combinations of dots and ripples with wavelengths around 100 nm are generated. The surfactant coverage and deposition direction determine the pattern type and the pattern orientation, respectively. A critical steady-state coverage for onset of dot formation and onset of ripple formation is in the range of 10{sup 15} and 5.10{sup 15} Xe/cm{sup 2}. The steady-state surface region consists of a thin amorphous metal silicide layer with high metal concentration in the ripple and dot regions. Pattern formation is explained by ion induced diffusion and phase separation of the initially flat amorphous silicide layer and subsequent ion beam erosion with composition dependent sputter yield. To investigate the role of initial phase separation we additionally compare the pattern formation for different other metal surfactants.

  17. On Pattern Formation Mechanisms for Lepidopteran Wing Patterns and Mammalian Coat Markings

    Science.gov (United States)

    Murray, J. D.

    1981-10-01

    The patterns on wings of Lepidoptera can be generated with a few pattern elements, but no mechanism has been suggested for producing them. I consider two of the basic patterns, namely, central symmetry and dependent patterns. A biochemically plausible model mechanism is proposed for generating major aspects of these patterns, based on a diffusing morphogen that activates a gene or colour-specific enzyme in a threshold manner to generate a stable heterogeneous spatial pattern. The model is applied to the determination stream hypothesis of Kuhn & von Engelhardt (Wilhelm Roux Arch. Entw Mech. Org. 130, 660 (1933)), and results from the model compared with their microcautery experiments on the pupal wing of Ephestia kuhniella. In the case of dependent patterns, results are compared with patterns on specific Papilionidae. For the same mechanism and a fixed set of parameters I demonstrate the important roles of geometry and scale on the spatial patterns obtained. The results and evidence presented here suggest the existence of diffusion fields of the order of several millimetres, which are very much larger than most embryonic fields. The existence of zones of polarizing activity is also indicated. Colour patterns on animals are considered to be genetically determined, but the mechanism is not known. I have previously suggested that a single mechanism that can exhibit an infinite variety of patterns is a candidate for that mechanism, and proposed that a reaction-diffusion system that can be diffusively driven unstable could be responsible for the laying down of the spacing patterns that generates the prepattern for animal coat markings. For illustrative purposes I consider a practical reaction mechanism, which exhibits substrate inhibition, and show that the geometry and scale of the domain (part of the epidermis) play a crucial role in the structural patterns that result. Patterns are obtained for a selection of geometries, and general features are related to the coat

  18. Ubiquitous expression of selenoprotein N transcripts in chicken tissues and early developmental expression pattern in skeletal muscles.

    Science.gov (United States)

    Zhang, Jiuli; Li, Jinlong; Zhang, Ziwei; Sun, Bo; Wang, Rihua; Jiang, Zhihui; Li, Shu; Xu, Shiwen

    2012-05-01

    Previous results revealed a ubiquitous expression pattern of selenoprotein N (SelN, SEPN1) in humans, zebrafish, and mouse, suggesting that it plays a potential role during the embryogenesis of these species. However, no information is known about the tissue distribution of SelN and mRNA expression analysis in the muscle tissues during development in birds. We analyzed the mRNA expression of SelN in 26 different tissues of 90-day-old chickens and the expression of SelN in the muscle tissues of 12-day-old chicken embryos and 15-month-old adult chickens by quantitative real-time PCR. The results showed that SelN transcripts were expressed widely in the chicken tissues. Moreover, the expression of SelN mRNA in skeletal muscles was present at a high level in whole embryos and at a lower level in postnatal stages. However, the expression of SelN mRNA in cardiac muscle showed a different expression pattern compared with skeletal muscles. Our data indicate that the expression of the SelN gene in chicken is ubiquitous, suggesting a role of SelN in the development of chick embryo skeletal muscles.

  19. Jamming and pattern formation in models of segregation

    Science.gov (United States)

    Rogers, Tim; McKane, Alan J.

    2012-04-01

    We investigate the Schelling model of social segregation, formulated as an intrinsically nonequilibrium system, in which the agents occupy districts (or patches) rather than sites on a grid. We show that this allows the equations governing the dynamical behavior of the model to be derived. Analysis of these equations reveals a jamming transition in the regime of low-vacancy density, and inclusion of a spatial dimension in the model leads to a pattern forming instability. Both of these phenomena exhibit unusual characteristics which may be studied through our approach.

  20. Pattern formation in a complex plasma in high magnetic fields.

    Science.gov (United States)

    Schwabe, M; Konopka, U; Bandyopadhyay, P; Morfill, G E

    2011-05-27

    Low-pressure room-temperature neon, argon, krypton, and air plasmas were studied in magnetic fields up to flux densities of 2.3 T. Filaments appeared parallel to the magnetic field lines, and patterns such as spirals and concentric circles formed in the perpendicular direction. We link these effects to the magnetization of the ions. We also used a layer of embedded microparticles as probes in the plasma. Their motion changed dramatically from a collective rotation of the whole ensemble in moderate magnetic fields to a rotation in several small vortices centered at the filaments. © 2011 American Physical Society

  1. Pattern Formation and Continuation in a Trineuron Ring with Delays

    Institute of Scientific and Technical Information of China (English)

    Shang Jiang GUO; Li Hong HUANG

    2007-01-01

    In this paper, we consider a single-directional ring of three neurons with delays. First, linear stability of the model is investigated by analyzing the associated characteristic transcendental equation. Next, we studied the local Hopf bifurcations and the spatio-temporal patterns of Hopf bifurcating periodic orbits. Basing on the normal form approach and the center manifold theory, we derive the formula for determining the properties of Hopf bifurcating periodic orbit, such as the direction of Hopf bifurcation. Finally, global existence conditions for Hopf bifurcating periodic orbits are derived by using degree theory methods.

  2. Pattern Formation and Growth Kinetics in Eutectic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Jing [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Growth patterns during liquid/solid phase transformation are governed by simultaneous effects of heat and mass transfer mechanisms, creation of new interfaces, jump of the crystallization units from liquid to solid and their rearrangement in the solid matrix. To examine how the above processes influence the scale of microstructure, two eutectic systems are chosen for the study: a polymeric system polyethylene glycol-p-dibromobenzene (PEG-DBBZ) and a simple molecular system succinonitrile (SCN)-camphor. The scaling law for SCN-camphor system is found to follow the classical Jackson-Hunt model of circular rod eutectic, where the diffusion in the liquid and the interface energy are the main physics governing the two-phase pattern. In contrast, a significantly different scaling law is observed for the polymer system. The interface kinetics of PEG phase and its solute concentration dependence thus have been critically investigated for the first time by directional solidification technique. A model is then proposed that shows that the two-phase pattern in polymers is governed by the interface diffusion and the interface kinetics. In SCN-camphor system, a new branch of eutectic, elliptical shape rodl, is found in thin samples where only one layer of camphor rods is present. It is found that the orientation of the ellipse can change from the major axis in the direction of the thickness to the direction of the width as the velocity and/or the sample thickness is decreased. A theoretical model is developed that predicts the spacing and orientation of the elliptical rods in a thin sample. The single phase growth patterns of SCN-camphor system were also examined with emphasis on the three-dimensional single cell and cell/dendrite transition. For the 3D single cell in a capillary tube, the entire cell shape ahead of the eutectic front can be described by the Saffmann-Taylor finger only at extremely low growth rate. A 3D directional solidification model is developed to

  3. Automated numerical simulation of biological pattern formation based on visual feedback simulation framework

    Science.gov (United States)

    Sun, Mingzhu; Xu, Hui; Zeng, Xingjuan; Zhao, Xin

    2017-01-01

    There are various fantastic biological phenomena in biological pattern formation. Mathematical modeling using reaction-diffusion partial differential equation systems is employed to study the mechanism of pattern formation. However, model parameter selection is both difficult and time consuming. In this paper, a visual feedback simulation framework is proposed to calculate the parameters of a mathematical model automatically based on the basic principle of feedback control. In the simulation framework, the simulation results are visualized, and the image features are extracted as the system feedback. Then, the unknown model parameters are obtained by comparing the image features of the simulation image and the target biological pattern. Considering two typical applications, the visual feedback simulation framework is applied to fulfill pattern formation simulations for vascular mesenchymal cells and lung development. In the simulation framework, the spot, stripe, labyrinthine patterns of vascular mesenchymal cells, the normal branching pattern and the branching pattern lacking side branching for lung branching are obtained in a finite number of iterations. The simulation results indicate that it is easy to achieve the simulation targets, especially when the simulation patterns are sensitive to the model parameters. Moreover, this simulation framework can expand to other types of biological pattern formation. PMID:28225811

  4. Dynamics of Surfactants Spreading on Gel-like Materials: Cracking and Pattern Formation

    CERN Document Server

    Spandagos, Constantine; Matar, Omar

    2010-01-01

    We study the dynamics of surfactants spreading on gels, paying particular attention to the pattern formation accompanying the flow. The latter results from gel-cracking, promoted by Marangoni stresses, and resemble starbursts.

  5. Pattern formation by temperature-gradient driven film instabilities in laterally confined geometries

    NARCIS (Netherlands)

    Nedelcu, M; Morariu, MD; Harkema, S; Voicu, NE; Steiner, U

    2005-01-01

    Film break-up driven by an electric field or temperature gradient typically exhibit a characteristic length scale. The presence of a lateral confinement significantly alters this pattern formation process.

  6. A survey on pattern formation of autonomous mobile robots: asynchrony, obliviousness and visibility

    Science.gov (United States)

    Yamauchi, Yukiko

    2013-12-01

    A robot system consists of autonomous mobile robots each of which repeats Look-Compute-Move cycles, where the robot observes the positions of other robots (Look phase), computes the track to the next location (Compute phase), and moves along the track (Move phase). In this survey, we focus on self-organization of mobile robots, especially their power of forming patterns. The formation power of a robot system is the class of patterns that the robots can form, and existing results show that the robot system's formation power is determined by their asynchrony, obliviousness, and visibility. We briefly survey existing results, with impossibilities and pattern formation algorithms. Finally, we present several open problems related to the pattern formation problem of mobile robots.

  7. [Family formation in Flanders: new patterns, different timing].

    Science.gov (United States)

    Lee, H Y; Rajulton, F; Wijewickrema, S; Lesthaeghe, R

    1987-01-01

    "The article presents a statistical study of the starting age and the speed of transitions in the process of family formation in Flanders. It contrasts two sets of generations, three groups according to educational achievement and three groups with differing religious practice. The methodology of shifted proportional hazard models is used and transition probabilities are fed into a semi-Markovian chain. Higher educational achievement results in later starting points, but not in a differing pace once started. By contrast, lower religious involvement speeds up the transitions to first sexual contact and premarital cohabitation, while it considerably retards the transition to parenthood among the generations born after 1950." (SUMMARY IN ENG AND FRE)

  8. Quantify work load and muscle functional activation patterns in neck-shoulder muscles of female sewing machine operators using surface electromyogram

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fei-ruo; HE Li-hua; WU Shan-shan; LI Jing-yun; YE Kang-pin; WANG Sheng

    2011-01-01

    Background Work-related musculoskeletal disorders (WMSDs) have high prevalence in sewing machine operators employed in the garment industry.Long work duration,sustained low level work and precise hand work are the main risk factors of neck-shoulder disorders for sewing machine operators.Surface electromyogram (sEMG) offers a valuable tool to determine muscle activity (internal exposure) and quantify muscular load (external exposure).During sustained and/or repetitive muscle contractions,typical changes of muscle fatigue in sEMG,as an increase in amplitude or a decrease as a shift in spectrum towards lower frequencies,can be observed.In this paper,we measured and quantified the muscle load and muscular activity patterns of neck-shoulder muscles in female sewing machine operators during sustained sewing machine operating tasks using sEMG.Methods A total of 18 healthy women sewing machine operators volunteered to participate in this study.Before their daily sewing machine operating task,we measured the maximal voluntary contractions (MVC) and 20%MVC of bilateral cervical erector spinae (CES) and upper trapezius (UT) respectively,then the sEMG signals of bilateral UT and CES were monitored and recorded continuously during 200 minutes of sustained sewing machine operating simultaneously which equals to 20 time windows with 10 minutes as one time window.After 200 minutes' work,we retest 20%MVC of four neck-shoulder muscles and recorded the sEMG signals.Linear analysis,including amplitude probability distribution frequency (APDF),amplitude analysis parameters such as roof mean square (RMS) and spectrum analysis parameter as median frequency (MF),were used to calculate and indicate muscle load and muscular activity of bilateral CES and UT.Results During 200 minutes of sewing machine operating,the median load for the left cervical erector spinae (LCES),right cervical erector spinae (RCES),left upper trapezius (LUT) and right upper trapezius (RUT) were 6.78%MVE,6.94

  9. Phosphatidylinositol 4,5-bisphosphate formation in rabbit skeletal and heart muscle membranes.

    Science.gov (United States)

    Varsányi, M; Messer, M; Brandt, N R; Heilmeyer, L M

    1986-08-14

    Incubation of rabbit skeletal muscle microsomes or isolated triads with gamma 32P-ATP/Mg2+ in the absence and in the presence of added phosphatidylinositol resulted in the formation of phosphatidylinositol 4-phosphate catalyzed by phosphatidylinositol kinase. When phosphatidylinositol 4-phosphate was added as exogenous substrate, phosphatidylinositol 4,5-bisphosphate was also formed demonstrating the presence of a membrane bound phosphatidylinositol 4-phosphate kinase. Triads were broken mechanically in a French press and separated on a continuous sucrose gradient. Incubation of these fractions with gamma 32P-ATP/Mg2+ resulted in a rapid labeling of phospholipid in a membrane fraction banding between transverse tubules and the terminal cisternae. Partial triad breakage and triad reformation experiments indicated that this phosphatidylinositol kinase was associated with T-tubules. When exogenous phosphatidylinositol 4-phosphate was employed as substrate phosphatidylinositol 4,5-bisphosphate and phosphatidic acid were formed, indicating the presence of all the enzymes of the polyphosphoinositide signaling system in this special membrane fraction. In contrast, heart muscle microsomes or plasma membranes can catalyze this reaction sequence from endogenous formed phosphatidylinositol 4-phosphate.

  10. Pattern formation and firing synchronization in networks of map neurons

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qingyun [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Duan Zhisheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Huang Lin [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Chen Guanrong [Department of Electronic Engineering, City University of Hong Kong, Hong Kong (China); Lu Qishao [School of Science, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)

    2007-10-15

    Patterns and collective phenomena such as firing synchronization are studied in networks of nonhomogeneous oscillatory neurons and mixtures of oscillatory and excitable neurons, with dynamics of each neuron described by a two-dimensional (2D) Rulkov map neuron. It is shown that as the coupling strength is increased, typical patterns emerge spatially, which propagate through the networks in the form of beautiful target waves or parallel ones depending on the size of networks. Furthermore, we investigate the transitions of firing synchronization characterized by the rate of firing when the coupling strength is increased. It is found that there exists an intermediate coupling strength; firing synchronization is minimal simultaneously irrespective of the size of networks. For further increasing the coupling strength, synchronization is enhanced. Since noise is inevitable in real neurons, we also investigate the effects of white noise on firing synchronization for different networks. For the networks of oscillatory neurons, it is shown that firing synchronization decreases when the noise level increases. For the missed networks, firing synchronization is robust under the noise conditions considered in this paper. Results presented in this paper should prove to be valuable for understanding the properties of collective dynamics in real neuronal networks.

  11. Radial-pattern formation in the polycarbonate substratum of recordable compact disks

    Science.gov (United States)

    Tanimura, M.; Ishikawa, I.; Tachibana, M.; Shinozaki, K.; Kojima, K.

    2001-09-01

    A radial pattern is found to form in the polycarbonate (PC) substratum of a recordable compact disk. Characteristic features of the pattern are that it is composed of about 80 needle-like regions, the shape of which closely resembles a thin film. In addition, white light is found to scatter at the needle-like region/matrix boundaries. This suggests that the PC substratum may have inferior transparency due to the formation of this pattern. Thus, it is important to understand the bifurcation of the radial-pattern formation from the viewpoint of materials science and engineering. Based on the mechanics of the PC viscous fluid, it has been found that the bifurcation of the pattern formation has a Reynolds number of about 10-3.

  12. Pattern formation in particle systems driven by color field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The structural evolution of systems with two kinds of particles driven in opposite directions, i.e., driven by a color field, is investigated by molecular dynamics simulations. Gaussian thermostat,a common treatment to restrict the thermal velocity of the particles in the systems, has been used so as to account for the dissipation of heat and allow the system to reach a steady state. It has been found that with the increase of the strngth of driving force (F), the system undergoes an obvious structural transition from an initially random mixing state to a state characterized by separate lanes and in each lane only one kind of particles exists. The analysis shows that the reason for the formation of lane structure is not only the increase of F but also the variation of particle friction coefficient. While using Ganssian thermostat the particle friction coefficient becomes a function of F. Increasing F leads to high particle friction coefficient and inevitably results in lane formation for strong enough driving force. When lifting the effect of F on friction coefficient and choosing a constant friction coefficient,our results show that for a given F there always exists a critical value of friction coefficient higher than which the system will develop into lane structure.

  13. Primary motor cortex neurons classified in a postural task predict muscle activation patterns in a reaching task.

    Science.gov (United States)

    Heming, Ethan A; Lillicrap, Timothy P; Omrani, Mohsen; Herter, Troy M; Pruszynski, J Andrew; Scott, Stephen H

    2016-04-01

    Primary motor cortex (M1) activity correlates with many motor variables, making it difficult to demonstrate how it participates in motor control. We developed a two-stage process to separate the process of classifying the motor field of M1 neurons from the process of predicting the spatiotemporal patterns of its motor field during reaching. We tested our approach with a neural network model that controlled a two-joint arm to show the statistical relationship between network connectivity and neural activity across different motor tasks. In rhesus monkeys, M1 neurons classified by this method showed preferred reaching directions similar to their associated muscle groups. Importantly, the neural population signals predicted the spatiotemporal dynamics of their associated muscle groups, although a subgroup of atypical neurons reversed their directional preference, suggesting a selective role in antagonist control. These results highlight that M1 provides important details on the spatiotemporal patterns of muscle activity during motor skills such as reaching.

  14. TIMP-1 Induces α-Smooth Muscle Actin in Fibroblasts to Promote Urethral Scar Formation

    Directory of Open Access Journals (Sweden)

    Yinglong Sa

    2015-04-01

    Full Text Available Background/Aims: Tissue inhibitor of metalloproteinases-1 (TIMP-1 has been reported to upregulate in urethral scar. However, the underlying molecular mechanisms remain undefined. Methods: Here, we studied levels of TIMP-1 and α-smooth muscle actin (α-SMA in the fibroblasts isolated from urethral scar tissues, compared to the fibroblasts isolated from normal urethra. Then we either overexpressed TIMP-1, or inhibited TIMP-1 by lentiviruses carrying a transgene or a short hairpin small interfering RNA for TIMP-1 in human fibroblasts. We examined the effects of modulation of TIMP-1 on α-SMA, and on epithelial-mesenchymal transition (EMT-related genes. We also studied the underlying mechanisms. Results: We detected significantly higher levels of TIMP-1 and α-smooth muscle actin (α-SMA in the fibroblasts isolated from urethral scar tissues, compared to the fibroblasts isolated from normal urethra. Moreover, the levels of TIMP-1 and α-SMA strongly correlated. Moreover, we found that TIMP-1 significantly increased levels of α-SMA, transforming growth factor β 1 (TGFβ1, Collagen I and some other key factors related to an enhanced EMT, suggesting that TIMP-1 may induce transformation of fibroblasts into myofibroblasts to promote tissue EMT to enhance the formation of urethral scar. Moreover, increases in TIMP-1 also induced an increase in fibroblast cell growth and cell invasion, in an ERK/MAPK-signaling-dependent manner. Conclusion: Our study thus highlights a pivotal role of TIMP-1 in urethral scar formation.

  15. Piperlongumine inhibits atherosclerotic plaque formation and vascular smooth muscle cell proliferation by suppressing PDGF receptor signaling

    Energy Technology Data Exchange (ETDEWEB)

    Son, Dong Ju [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Kim, Soo Yeon [Division of Life Science, Korea Basic Science Institute, Daejeon (Korea, Republic of); Han, Seong Su [University of Iowa Carver College of Medicine, Department of Pathology, Iowa City, IA (United States); Kim, Chan Woo [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Department of Bioinspired Science, Ehwa Womans University, Seoul (Korea, Republic of); Kumar, Sandeep [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Park, Byeoung Soo [Nanotoxtech Co., Ansan (Korea, Republic of); Lee, Sung Eun [Division of Applied Biology and Chemistry, Kyungpook National University, Daegu (Korea, Republic of); Yun, Yeo Pyo [College of Pharmacy, Chungbuk National University, Cheongju (Korea, Republic of); Jo, Hanjoong, E-mail: hjo@emory.edu [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Department of Bioinspired Science, Ehwa Womans University, Seoul (Korea, Republic of); Park, Young Hyun, E-mail: pyh012@sch.ac.kr [Department of Food Science and Nutrition, College of Natural Sciences, Soonchunhyang University, Asan (Korea, Republic of)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer Anti-atherogenic effect of PL was examined using partial carotid ligation model in ApoE KO mice. Black-Right-Pointing-Pointer PL prevented atherosclerotic plaque development, VSMCs proliferation, and NF-{kappa}B activation. Black-Right-Pointing-Pointer Piperlongumine reduced vascular smooth muscle cell activation through PDGF-R{beta} and NF-{kappa}B-signaling. Black-Right-Pointing-Pointer PL may serve as a new therapeutic molecule for atherosclerosis treatment. -- Abstract: Piperlongumine (piplartine, PL) is an alkaloid found in the long pepper (Piper longum L.) and has well-documented anti-platelet aggregation, anti-inflammatory, and anti-cancer properties; however, the role of PL in prevention of atherosclerosis is unknown. We evaluated the anti-atherosclerotic potential of PL in an in vivo murine model of accelerated atherosclerosis and defined its mechanism of action in aortic vascular smooth muscle cells (VSMCs) in vitro. Local treatment with PL significantly reduced atherosclerotic plaque formation as well as proliferation and nuclear factor-kappa B (NF-{kappa}B) activation in an in vivo setting. PL treatment in VSMCs in vitro showed inhibition of migration and platelet-derived growth factor BB (PDGF-BB)-induced proliferation to the in vivo findings. We further identified that PL inhibited PDGF-BB-induced PDGF receptor beta activation and suppressed downstream signaling molecules such as phospholipase C{gamma}1, extracellular signal-regulated kinases 1 and 2 and Akt. Lastly, PL significantly attenuated activation of NF-{kappa}B-a downstream transcriptional regulator in PDGF receptor signaling, in response to PDGF-BB stimulation. In conclusion, our findings demonstrate a novel, therapeutic mechanism by which PL suppresses atherosclerosis plaque formation in vivo.

  16. Lateral inhibition-induced pattern formation controlled by the size and geometry of the cell.

    Science.gov (United States)

    Seirin Lee, Sungrim

    2016-09-01

    Pattern formation in development biology is one of the fundamental processes by which cells change their functions. It is based on the communication of cells via intra- and intercellular dynamics of biochemicals. Thus, the cell is directly involved in biochemical interactions. However, many theoretical approaches describing biochemical pattern formation have usually neglected the cell's role or have simplified the subcellular process without considering cellular aspects despite the cell being the environment where biochemicals interact. On the other hand, recent experimental observations suggest that a change in the physical conditions of cell-to-cell contact can result in a change in cell fate and tissue patterning in a lateral inhibition system. Here we develop a mathematical model by which biochemical dynamics can be directly observed with explicitly expressed cell structure and geometry in higher dimensions, and reconsider pattern formation by lateral inhibition of the Notch-Delta signaling pathway. We explore how the physical characteristic of cell, such as cell geometry or size, influences the biochemical pattern formation in a multi-cellular system. Our results suggest that a property based on cell geometry can be a novel mechanism for symmetry breaking inducing cell asymmetry. We show that cell volume can critically influence cell fate determination and pattern formation at the tissue level, and the surface area of the cell-to-cell contact can directly affect the spatial range of patterning.

  17. Time rescaling and pattern formation in biological evolution.

    Science.gov (United States)

    Igamberdiev, Abir U

    2014-09-01

    Biological evolution is analyzed as a process of continuous measurement in which biosystems interpret themselves in the environment resulting in changes of both. This leads to rescaling of internal time (heterochrony) followed by spatial reconstructions of morphology (heterotopy). The logical precondition of evolution is the incompleteness of biosystem's internal description, while the physical precondition is the uncertainty of quantum measurement. The process of evolution is based on perpetual changes in interpretation of information in the changing world. In this interpretation the external biospheric gradients are used for establishment of new features of organization. It is concluded that biological evolution involves the anticipatory epigenetic changes in the interpretation of genetic symbolism which cannot generally be forecasted but can provide canalization of structural transformations defined by the existing organization and leading to predictable patterns of form generation.

  18. Developmental waves in myxobacteria: A distinctive pattern formation mechanism

    Science.gov (United States)

    Igoshin, Oleg A.; Neu, John; Oster, George

    2004-10-01

    In early stages of their development, starving myxobacteria organize their motion to produce a periodic pattern of traveling cell density waves. These waves arise from coordination of individual cell reversals by contact signaling when they collide. Unlike waves generated by reaction-diffusion instabilities, which annihilate on collision, myxobacteria waves appear to pass through one another unaffected. Here we analyze a mathematical model of these waves developed earlier [Igoshin , Proc. Natl. Acad. Sci. USA 98, 14 913 (2001)]. The mechanisms which generate and maintain the density waves are clearly revealed by tracing the reversal loci of individual cells. An evolution equation of reversal point density is derived in the weak-signaling limit. Linear stability analysis determines parameters favorable for the development of the waves. Numerical solutions demonstrate the stability of the fully developed nonlinear waves.

  19. Pattern formation due to non-linear vortex diffusion

    Science.gov (United States)

    Wijngaarden, Rinke J.; Surdeanu, R.; Huijbregtse, J. M.; Rector, J. H.; Dam, B.; Einfeld, J.; Wördenweber, R.; Griessen, R.

    Penetration of magnetic flux in YBa 2Cu 3O 7 superconducting thin films in an external magnetic field is visualized using a magneto-optic technique. A variety of flux patterns due to non-linear vortex diffusion is observed: (1) Roughening of the flux front with scaling exponents identical to those observed in burning paper including two distinct regimes where respectively spatial disorder and temporal disorder dominate. In the latter regime Kardar-Parisi-Zhang behavior is found. (2) Fractal penetration of flux with Hausdorff dimension depending on the critical current anisotropy. (3) Penetration as ‘flux-rivers’. (4) The occurrence of commensurate and incommensurate channels in films with anti-dots as predicted in numerical simulations by Reichhardt, Olson and Nori. It is shown that most of the observed behavior is related to the non-linear diffusion of vortices by comparison with simulations of the non-linear diffusion equation appropriate for vortices.

  20. Genetic oscillations. A Doppler effect in embryonic pattern formation.

    Science.gov (United States)

    Soroldoni, Daniele; Jörg, David J; Morelli, Luis G; Richmond, David L; Schindelin, Johannes; Jülicher, Frank; Oates, Andrew C

    2014-07-11

    During embryonic development, temporal and spatial cues are coordinated to generate a segmented body axis. In sequentially segmenting animals, the rhythm of segmentation is reported to be controlled by the time scale of genetic oscillations that periodically trigger new segment formation. However, we present real-time measurements of genetic oscillations in zebrafish embryos showing that their time scale is not sufficient to explain the temporal period of segmentation. A second time scale, the rate of tissue shortening, contributes to the period of segmentation through a Doppler effect. This contribution is modulated by a gradual change in the oscillation profile across the tissue. We conclude that the rhythm of segmentation is an emergent property controlled by the time scale of genetic oscillations, the change of oscillation profile, and tissue shortening.

  1. Pattern formation during electrodeposition of copper-antimony alloys

    Directory of Open Access Journals (Sweden)

    Vasil S. Kostov

    2016-04-01

    Full Text Available Aim of the present study is to establish the conditions of the electrolysis for the preparation of structured and unstressed purple-pink coatings of copper-antimony alloys, including their phase characterization. Also the task of the present investigation is, by changing drastically the metal content in the methanesulfonic electrolyte to find out the conditions of electrolysis where the self-organization of the different phases is expressed by higher-order structures - not only waves but also spirals and targets. The possibility to obtain copper-antimony alloy with up to 80 wt. % Sb from methanesulfonic acid is shown. The deposition rate, morphology and the phase composition of the obtained coatings are established. The phenomena of formation of spatio-temporal structures in this alloy are described.It is determined that the observed structures consist of Cu2Sb and Cu11Sb3 intermetallic phases.

  2. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization

    Directory of Open Access Journals (Sweden)

    Hans-Georg Braun

    2013-02-01

    Full Text Available The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO, molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness < 10 nm result from an interplay between dewetting patterns and diffusion limited growth pattern of ordered lamella growing within the dewetting areas. Besides structure formation of hydrophilic PEO molecules, n-alkylterminated (hydrophobic PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups.

  3. Estimating dew formation in rice, using seasonally averaged diel patterns of weather variables

    NARCIS (Netherlands)

    Luo, W.; Goudriaan, J.

    2004-01-01

    If dew formation cannot be measured it has to be estimated. Available simulation models for estimating dew formation require hourly weather data as input. However, such data are not available for places without an automatic weather station. In such cases the diel pattern of weather variables might

  4. Exploring Formative E-Assessment: Using Case Stories and Design Patterns

    Science.gov (United States)

    Daly, Caroline; Pachler, Norbert; Mor, Yishay; Mellar, Harvey

    2010-01-01

    This article presents key findings from a Joint Information Systems Committee-funded project, which aimed to identify existing practices where technologies contribute to formative assessment and identify processes that take place around formative assessment where technologies play a significant role. Using a design pattern methodology, the project…

  5. Rectus muscle excyclorotation and V-pattern strabismus: a quantitative appraisal of clinical relevance in syndromic craniosynostosis.

    Science.gov (United States)

    Dagi, Linda R; MacKinnon, Sarah; Zurakowski, David; Prabhu, Sanjay P

    2017-03-20

    V-pattern strabismus observed with syndromic craniosynostosis has been attributed to disparate causes. We compared severity of V pattern with degree of excyclorotation of rectus muscles to appraise significance of this proposed aetiology. 43 patients with Apert, Crouzon or Pfeiffer syndrome referred to Boston Children's Hospital Department of Ophthalmology were identified. 28 met inclusion criteria for retrospective cohort study, specifically: (1) sensorimotor measurements in minimum of seven cardinal gazes, (2) quantified fundus torsion and (3) orbital CT imaging sufficient to measure rectus muscle cyclorotation in coronal and quasicoronal planes, posteriorly (near orbital apex) and anteriorly (near pulleys). Patients were placed in one of four V-pattern severity groups. The most severe group demonstrated inability to elevate abducted eye above midline with characteristic 'seesaw' misalignment during horizontal saccades. Rectus muscle cyclorotation was measured by paediatric neuroradiologist blinded to group placement. Primary outcome was correlation of severity of V pattern with degree of excyclorotation. Secondary outcome was correlation of severity with craniosynostosis syndrome. Increasing severity of V pattern correlated with greater excyclorotation in anterior coronal (p=0.009), anterior quasicoronal (p=0.021), posterior coronal (p=0.014) and posterior quasicoronal (p=0.040) planes for moderate-to-severe V pattern. Even greater excyclorotation was associated with seesaw V pattern in anterior quasicoronal (p=0.004) and posterior quasicoronal (p=0.001) views. Highly significant association was found between Apert syndrome and severity of V pattern (p=0.004). Severity of V pattern is associated with magnitude of excyclorotation. More severe V pattern and seesaw strabismus noted with Apert syndrome may relate to distinctive orbital morphology. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please

  6. Inhibition of Smooth Muscle β-Catenin Hinders Neointima Formation After Vascular Injury.

    Science.gov (United States)

    Riascos-Bernal, Dario F; Chinnasamy, Prameladevi; Gross, Jordana N; Almonte, Vanessa; Egaña-Gorroño, Lander; Parikh, Dippal; Jayakumar, Smitha; Guo, Liang; Sibinga, Nicholas E S

    2017-05-01

    Smooth muscle cells (SMCs) contribute to neointima formation after vascular injury. Although β-catenin expression is induced after injury, whether its function is essential in SMCs for neointimal growth is unknown. Moreover, although inhibitors of β-catenin have been developed, their effects on SMC growth have not been tested. We assessed the requirement for SMC β-catenin in short-term vascular homeostasis and in response to arterial injury and investigated the effects of β-catenin inhibitors on vascular SMC growth. We used an inducible, conditional genetic deletion of β-catenin in SMCs of adult mice. Uninjured arteries from adult mice lacking SMC β-catenin were indistinguishable from controls in terms of structure and SMC marker gene expression. After carotid artery ligation, however, vessels from mice lacking SMC β-catenin developed smaller neointimas, with lower neointimal cell proliferation and increased apoptosis. SMCs lacking β-catenin showed decreased mRNA expression of Mmp2, Mmp9, Sphk1, and S1pr1 (genes that promote neointima formation), higher levels of Jag1 and Gja1 (genes that inhibit neointima formation), decreased Mmp2 protein expression and secretion, and reduced cell invasion in vitro. Moreover, β-catenin inhibitors PKF118-310 and ICG-001 limited growth of mouse and human vascular SMCs in a dose-dependent manner. SMC β-catenin is dispensable for maintenance of the structure and state of differentiation of uninjured adult arteries, but is required for neointima formation after vascular injury. Pharmacological β-catenin inhibitors hinder growth of human vascular SMCs. Thus, inhibiting β-catenin has potential as a therapy to limit SMC accumulation and vascular obstruction. © 2017 American Heart Association, Inc.

  7. Antioxidant Treatment Reduces Formation of Structural Cores and Improves Muscle Function in RYR1Y522S/WT Mice

    Directory of Open Access Journals (Sweden)

    Antonio Michelucci

    2017-01-01

    Full Text Available Central core disease (CCD is a congenital myopathy linked to mutations in the ryanodine receptor type 1 (RYR1, the sarcoplasmic reticulum Ca2+ release channel of skeletal muscle. CCD is characterized by formation of amorphous cores within muscle fibers, lacking mitochondrial activity. In skeletal muscle of RYR1Y522S/WT knock-in mice, carrying a human mutation in RYR1 linked to malignant hyperthermia (MH with cores, oxidative stress is elevated and fibers present severe mitochondrial damage and cores. We treated RYR1Y522S/WT mice with N-acetylcysteine (NAC, an antioxidant provided ad libitum in drinking water for either 2 or 6 months. Our results show that 2 months of NAC treatment starting at 2 months of age, when mitochondrial and fiber damage was still minimal, (i reduce formation of unstructured and contracture cores, (ii improve muscle function, and (iii decrease mitochondrial damage. The beneficial effect of NAC treatment is also evident following 6 months of treatment starting at 4 months of age, when structural damage was at an advanced stage. NAC exerts its protective effect likely by lowering oxidative stress, as supported by the reduction of 3-NT and SOD2 levels. This work suggests that NAC administration is beneficial to prevent mitochondrial damage and formation of cores and improve muscle function in RYR1Y522S/WT mice.

  8. Pattern formation induced by cross-diffusion in a predator-prey system

    Institute of Scientific and Technical Information of China (English)

    Sun Gui-Quan; Jin Zhen; Liu Quan-Xing; Li Li

    2008-01-01

    This paper considers the Holling-Tanner model for predator-prey with self and cross-diffusion.From the Turing theory,it is believed that there is no Turing pattern formation for the equal self-diffusion coefficients.However,combined with cross-diffusion,it shows that the system will exhibit spotted pattern by both mathematical analysis and numerical simulations.Furthermore,nsynchrony of the predator and the prey in the space.The obtained results show that cross-diffusion plays an important role on the pattern formation of the predator-prey system.

  9. Effect of glucocorticoid on prostaglandin E1 mediated cyclic AMP formation by vascular smooth muscle cells.

    Science.gov (United States)

    Yasunari, K; Kohno, M; Murakawa, K; Yokokawa, K; Takeda, T

    1988-12-01

    The effect of glucocorticoid on the prostaglandin E1 (PGE1)-mediated cyclic AMP (cAMP) formation by vascular smooth muscle cells (VSMC) from renal arteries (RA) was studied in rats. Dexamethasone (DEX) at concentrations ranging from 10(-10) to approximately 10(-8) mol/l dose-dependently potentiates the PGE1-mediated response. This facilitation began at 6 h and reached its maximum after 24 h of DEX administration. Aldosterone (10(-6) mol/l) did not affect the dose-response curve of PGE1. Inhibitors of protein and RNA synthesis blocked this glucocorticoid effect. The basal activity of adenylate cyclase in DEX-treated cells was twice as high as in control cells. Treatment of VSMC with DEX increased cholera toxin- and pertussis toxin-stimulated adenylate cyclase activity. DEX treatment also augments forskolin-stimulated adenylate cyclase activity. These results suggest that DEX increases PGE1-mediated cAMP formation of VSMC from RA through a mechanism that involves the induction of protein synthesis, and that the activation of the catalytic unit may play some role in this facilitating process.

  10. Trunk muscles activation pattern during walking in subjects with and without chronic low back pain: a systematic review.

    Science.gov (United States)

    Ghamkhar, Leila; Kahlaee, Amir Hossein

    2015-05-01

    The purpose of this study was to identify how activity patterns of trunk muscles change in chronic LBP during walking. TYPE: This was a systematic review ELSEVIER, Pro Quest, PubMed, Google scholar and MEDLINE electronic databases were explored for the period from the earliest researchable time to August 2014. Articles investigating patients with chronic LBP and analyzing trunk muscles with surface electromyography (EMG) during walking were included. All studies had a case-control design. Characteristics of the LBP patients, sample size, studied muscles and EMG parameters, and gait condition and velocity were investigated. Studies were rated as "A" to "E" (5 grades defined) based on study design and performance. Multifidus (MF), erector spinae (ES), external oblique (EO), and rectus abdominus (RA) muscle activity level were found to be increased in LBP subjects in comparison with controls. ES activity in subjects with LBP was found not to be as adaptive to walking velocity alterations as in healthy controls. Individuals with chronic LBP exhibit higher global trunk muscle activity. However, the activation pattern appears to vary depending on subphases of gait. It seems that increased walking velocity challenges the stability of the spine and the control system increases muscular activation and variability level to cope with this problem. Further standardized studies with subtyped LBP cases are needed to clarify the controversial findings. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  11. Formation of Self-Organized Anode Patterns in Arc Discharge Simulations

    CERN Document Server

    Trelles, Juan Pablo

    2013-01-01

    Pattern formation and self-organization are phenomena commonly observed experimentally in diverse types of plasma systems, including atmospheric-pressure electric arc discharges. However, numerical simulations reproducing anode pattern formation in arc discharges have proven exceedingly elusive. Time-dependent three-dimensional thermodynamic nonequilibrium simulations reveal the spontaneous formation of self-organized patterns of anode attachment spots in the free-burning arc, a canonical thermal plasma flow established by a constant DC current between an axi-symmetric electrodes configuration in the absence of external forcing. The number of spots, their size, and distribution within the pattern depend on the applied total current and on the resolution of the spatial discretization, whereas the main properties of the plasma flow, such as maximum temperatures, velocity, and voltage drop, depend only on the former. The sensibility of the solution to the spatial discretization stresses the computational require...

  12. Modular organization of muscle activity patterns in the leading and trailing limbs during obstacle clearance in healthy adults.

    Science.gov (United States)

    MacLellan, Michael J

    2017-07-01

    Human locomotor patterns require precise adjustments to successfully navigate complex environments. Studies suggest that the central nervous system may control such adjustments through supraspinal signals modifying a basic locomotor pattern at the spinal level. To explore this proposed control mechanism in the leading and trailing limbs during obstructed walking, healthy young adults stepped over obstacles measuring 0.1 and 0.2 m in height. Unobstructed walking with no obstacle present was also performed as a baseline. Full body three-dimensional kinematic data were recorded and electromyography (EMG) was collected from 14 lower limb muscles on each side of the body. EMG data were analyzed using two techniques: by mapping the EMG data to the approximate location of the motor neuron pools on the lumbosacral enlargement of the spinal cord and by applying a nonnegative matrix factorization algorithm to unilateral and bilateral muscle activations separately. Results showed that obstacle clearance may be achieved not only with the addition of a new activation pattern in the leading limb, but with a temporal shift of a pattern present during unobstructed walking in both the leading and trailing limbs. An investigation of the inter-limb coordination of these patterns suggested a strong bilateral linkage between lower limbs. These results highlight the modular organization of muscle activation in the leading and trailing limbs, as well as provide a mechanism of control when implementing a locomotor adjustment when stepping over an obstacle.

  13. Pattern formation in vibrated beds of dry and wet granular materials

    Science.gov (United States)

    Chuan Lim, Eldin Wee

    2014-01-01

    The Discrete Element Method was coupled with a capillary liquid bridge force model for computational studies of pattern formation in vibrated granular beds containing dry or wet granular materials. Depending on the vibration conditions applied, hexagonal, stripes, or cellular pattern was observed in the dry vibrated granular bed. In each of these cases, the same hexagonal, stripes, or cellular pattern was also observed in the spatial distribution of the magnitudes of particle-particle collision forces prior to the formation of the corresponding actual pattern in physical distributions of the particles. This seemed to suggest that the pattern formation phenomenon of vibrated granular bed systems might be the result of a two-dimensional Newton's cradle effect. In the presence of a small amount of wetness, these patterns were no longer formed in the vibrated granular beds under the same corresponding set of vibration conditions. Despite the relatively much weaker capillary forces arising from the simulated liquid bridges between particles compared with particle-particle collision forces, the spatial distributions of these collision forces, physical distributions of particles, as well as time profiles of average collision forces were altered significantly in comparison with the corresponding distributions and profiles observed for the dry vibrated granular beds. This seemed to suggest the presence of a two-dimensional Stokes' cradle effect in these wet vibrated granular bed systems which disrupted the formation of patterns in the wet granular materials that would have been observed in their dry counterparts.

  14. Impaired growth of denervated muscle contributes to contracture formation following neonatal brachial plexus injury.

    Science.gov (United States)

    Nikolaou, Sia; Peterson, Elizabeth; Kim, Annie; Wylie, Christopher; Cornwall, Roger

    2011-03-02

    The etiology of shoulder and elbow contractures following neonatal brachial plexus injury is incompletely understood. With use of a mouse model, the current study tests the novel hypothesis that reduced growth of denervated muscle contributes to contractures following neonatal brachial plexus injury. Unilateral brachial plexus injuries were created in neonatal mice by supraclavicular C5-C6 nerve root excision. Shoulder and elbow range of motion was measured four weeks after injury. Fibrosis, cross-sectional area, and functional length of the biceps, brachialis, and subscapularis muscles were measured over four weeks following injury. Muscle satellite cells were cultured from denervated and control biceps muscles to assess myogenic capability. In a comparison group, shoulder motion and subscapularis length were assessed following surgical excision of external rotator muscles. Shoulder internal rotation and elbow flexion contractures developed on the involved side within four weeks following brachial plexus injury. Excision of the biceps and brachialis muscles relieved the elbow flexion contractures. The biceps muscles were histologically fibrotic, whereas fatty infiltration predominated in the brachialis and rotator cuff muscles. The biceps and brachialis muscles displayed reduced cross-sectional and longitudinal growth compared with the contralateral muscles. The upper subscapularis muscle similarly displayed reduced longitudinal growth, with the subscapularis shortening correlating with internal rotation contracture. However, excision of the external rotators without brachial plexus injury caused no contractures or subscapularis shortening. Myogenically capable satellite cells were present in denervated biceps muscles despite impaired muscle growth in vivo. Injury of the upper trunk of the brachial plexus leads to impaired growth of the biceps and brachialis muscles, which are responsible for elbow flexion contractures, and impaired growth of the subscapularis

  15. Medial hamstring muscle activation patterns are affected 1-6 years after ACL reconstruction using hamstring autograft.

    Science.gov (United States)

    Arnason, Stefán Magni; Birnir, Bjartmar; Guðmundsson, Tómas Emil; Guðnason, Garðar; Briem, Kristín

    2014-05-01

    Although changes in hamstring muscle morphology after anterior cruciate ligament reconstruction (ACLR) using a semitendinosus autograft hamstrings-gracilis (HG) of the ipsilateral limb are recognized, alterations in muscle activation patterns have not been extensively studied. The purpose of this controlled laboratory trial was therefore to monitor muscle activation levels of the medial (MH) and lateral (LH) hamstring muscles in athletes who had undergone ACLR using a HG autograft and to contrast these to activation levels demonstrated by healthy controls. Surface electromyography (EMG) was sampled from bilateral hamstring muscles of 18 athletes 1-6 years after ACLR and 18 matched controls (CTRL) during the performance of two dissimilar exercises, both involving eccentric knee flexor activity. Peak normalized muscle activation levels were identified for MH and LH of both limbs during the performance of the Nordic Hamstring (NH) exercise and TRX) hamstring curl (TRX) exercise. A statistically significant limb by exercise interaction was found for peak activation levels of LH, due to significant interlimb differences in activation during the performance of the TRX exercise compared to more symmetrical activation during the NH (p exercise type (p = 0.025). Whereas CTRL group participants consistently favoured one limb over the other during the performance of both exercises, ACLR participants demonstrated dissimilar peak MH activation patterns between limbs during the performance of the NH exercise compared to the TRX. In light of these results and considering the surgical procedure, patients who undergo ACLR using a HG autograft from the ipsilateral limb may benefit from post-operative rehabilitation that involves muscle activation and strengthening specifically targeting the MH component.

  16. Muscle activity patterns and spinal shrinkage in office workers using a sit-stand workstation versus a sit workstation.

    Science.gov (United States)

    Gao, Ying; Cronin, Neil J; Pesola, Arto J; Finni, Taija

    2016-10-01

    Reducing sitting time by means of sit-stand workstations is an emerging trend, but further evidence is needed regarding their health benefits. This cross-sectional study compared work time muscle activity patterns and spinal shrinkage between office workers (aged 24-62, 58.3% female) who used either a sit-stand workstation (Sit-Stand group, n = 10) or a traditional sit workstation (Sit group, n = 14) for at least the past three months. During one typical workday, muscle inactivity and activity from quadriceps and hamstrings were monitored using electromyography shorts, and spinal shrinkage was measured using stadiometry before and after the workday. Compared with the Sit group, the Sit-Stand group had less muscle inactivity time (66.2 ± 17.1% vs. 80.9 ± 6.4%, p = 0.014) and more light muscle activity time (26.1 ± 12.3% vs. 14.9 ± 6.3%, p = 0.019) with no significant difference in spinal shrinkage (5.62 ± 2.75 mm vs. 6.11 ± 2.44 mm). This study provides evidence that working with sit-stand workstations can promote more light muscle activity time and less inactivity without negative effects on spinal shrinkage. Practitioner Summary: This cross-sectional study compared the effects of using a sit-stand workstation to a sit workstation on muscle activity patterns and spinal shrinkage in office workers. It provides evidence that working with a sit-stand workstation can promote more light muscle activity time and less inactivity without negative effects on spinal shrinkage.

  17. Exposure to Radiofrequency Radiation Emitted from Common Mobile Phone Jammers Alters the Pattern of Muscle Contractions: an Animal Model Study

    Directory of Open Access Journals (Sweden)

    Rafati A.

    2015-09-01

    Full Text Available Introduction: The rapid growth of wireless communication technologies has caused public concerns regarding the biological effects of electromagnetic radiations on human health. Some early reports indicated a wide variety of non-thermal effects of electromagnetic radiation on amphibians such as the alterations of the pattern of muscle extractions. This study is aimed at investigating the effects of exposure to radiofrequency (RF radiation emitted from mobile phone jammers on the pulse height of contractions, the time interval between two subsequent contractions and the latency period of frog’s isolated gastrocnemius muscle after stimulation with single square pulses of 1V (1 Hz. Materials and Methods: Frogs were kept in plastic containers in a room. Animals in the jammer group were exposed to radiofrequency (RF radiation emitted from a common Jammer at a distance of 1m from the jammer’s antenna for 2 hours while the control frogs were only sham exposed. Then animals were sacrificed and isolated gastrocnemius muscles were exposed to on/off jammer radiation for 3 subsequent 10 minute intervals. Isolated gastrocnemius muscles were attached to the force transducer with a string. Using a PowerLab device (26-T, the pattern of muscular contractions was monitored after applying single square pulses of 1V (1 Hz as stimuli. Results: The findings of this study showed that the pulse height of muscle contractions could not be affected by the exposure to electromagnetic fields. However, the latency period was effectively altered in RF-exposed samples. However, none of the experiments could show an alteration in the time interval between two subsequent contractions after exposure to electromagnetic fields. Conclusion: These findings support early reports which indicated a wide variety of non-thermal effects of electromagnetic radiation on amphibians including the effects on the pattern of muscle extractions.

  18. Cortical instability drives periodic supracellular actin pattern formation in epithelial tubes.

    Science.gov (United States)

    Hannezo, Edouard; Dong, Bo; Recho, Pierre; Joanny, Jean-François; Hayashi, Shigeo

    2015-07-14

    An essential question of morphogenesis is how patterns arise without preexisting positional information, as inspired by Turing. In the past few years, cytoskeletal flows in the cell cortex have been identified as a key mechanism of molecular patterning at the subcellular level. Theoretical and in vitro studies have suggested that biological polymers such as actomyosin gels have the property to self-organize, but the applicability of this concept in an in vivo setting remains unclear. Here, we report that the regular spacing pattern of supracellular actin rings in the Drosophila tracheal tubule is governed by a self-organizing principle. We propose a simple biophysical model where pattern formation arises from the interplay of myosin contractility and actin turnover. We validate the hypotheses of the model using photobleaching experiments and report that the formation of actin rings is contractility dependent. Moreover, genetic and pharmacological perturbations of the physical properties of the actomyosin gel modify the spacing of the pattern, as the model predicted. In addition, our model posited a role of cortical friction in stabilizing the spacing pattern of actin rings. Consistently, genetic depletion of apical extracellular matrix caused strikingly dynamic movements of actin rings, mirroring our model prediction of a transition from steady to chaotic actin patterns at low cortical friction. Our results therefore demonstrate quantitatively that a hydrodynamical instability of the actin cortex can trigger regular pattern formation and drive morphogenesis in an in vivo setting.

  19. Distribution patterns of fibre types in the triceps surae muscle group of chimpanzees and orangutans.

    Science.gov (United States)

    Myatt, Julia P; Schilling, Nadja; Thorpe, Susannah K S

    2011-04-01

    Different locomotor and postural demands are met partly due to the varying properties and proportions of the muscle fibre types within the skeletal muscles. Such data are therefore important in understanding the subtle relationships between morphology, function and behaviour. The triceps surae muscle group is of particular interest when studying our closest living relatives, the non-human great apes, as they lack a significant external Achilles tendon, crucial to running locomotion in humans and other cursorial species. The aim of this study, therefore, was to determine the proportions of type I (slow) and type II (fast) fibres throughout these muscles in chimpanzees and orangutans using immunohistochemistry. The orangutan had a higher proportion of type I fibres in all muscles compared with the chimpanzees, related to their slower, more controlled movements in their arboreal habitat. The higher proportion of type II fibres in the chimpanzees likely reflects a compromise between their need for controlled mobility when arboreal, and greater speed and power when terrestrial. Overall, the proportion of slow fibres was greater in the soleus muscle compared with the gastrocnemius muscles, and there was some evidence of proximal to distal and medial to lateral variations within some muscles. This study has shown that not only do orangutans and chimpanzees have very different muscle fibre populations that reflect their locomotor repertoires, but it also shows how the proportion of fibre types provides an additional mechanism by which the performance of a muscle can be modulated to suit the needs of a species.

  20. Role of the medial medullary reticular formation in relaying vestibular signals to the diaphragm and abdominal muscles

    Science.gov (United States)

    Mori, R. L.; Bergsman, A. E.; Holmes, M. J.; Yates, B. J.

    2001-01-01

    Changes in posture can affect the resting length of respiratory muscles, requiring alterations in the activity of these muscles if ventilation is to be unaffected. Recent studies have shown that the vestibular system contributes to altering respiratory muscle activity during movement and changes in posture. Furthermore, anatomical studies have demonstrated that many bulbospinal neurons in the medial medullary reticular formation (MRF) provide inputs to phrenic and abdominal motoneurons; because this region of the reticular formation receives substantial vestibular and other movement-related input, it seems likely that medial medullary reticulospinal neurons could adjust the activity of respiratory motoneurons during postural alterations. The objective of the present study was to determine whether functional lesions of the MRF affect inspiratory and expiratory muscle responses to activation of the vestibular system. Lidocaine or muscimol injections into the MRF produced a large increase in diaphragm and abdominal muscle responses to vestibular stimulation. These vestibulo-respiratory responses were eliminated following subsequent chemical blockade of descending pathways in the lateral medulla. However, inactivation of pathways coursing through the lateral medulla eliminated excitatory, but not inhibitory, components of vestibulo-respiratory responses. The simplest explanation for these data is that MRF neurons that receive input from the vestibular nuclei make inhibitory connections with diaphragm and abdominal motoneurons, whereas a pathway that courses laterally in the caudal medulla provides excitatory vestibular inputs to these motoneurons.

  1. Hypothetical way of pollen aperture patterning. 2. Formation of polycolpate patterns and pseudoaperture geometry.

    Science.gov (United States)

    Pozhidaev

    2000-05-01

    Deviant forms of polycolpate pollen, differing from the typical pattern in the number and arrangement of apertures, are found to be similar in distantly related dicotyledon taxa. The range of variation of common and deviant aperture patterns may be arranged as a continuous series, which may be described as a gradual and geometrically regular transformation of the deviant form with a meridional circular colpus to one of the common polycolpate conditions. Similar series have been observed in the taxa with colporate and pseudocolpate pollen. All possible spatial isomers and their mirror symmetrical variants of the deviant polycolpate and polypseudocolpate pollen have been predicted in terms of the suggested regularities of aperture multiplication. Some of them have been identified in the samples studied.

  2. Effect of substrate temperature on pattern formation of nanoparticles from volatile drops.

    Science.gov (United States)

    Parsa, Maryam; Harmand, Souad; Sefiane, Khellil; Bigerelle, Maxence; Deltombe, Raphaël

    2015-03-24

    This study investigates pattern formation during evaporation of water-based nanofluid sessile droplets placed on a smooth silicon surface at various temperatures. An infrared thermography technique was employed to observe the temperature distribution along the air-liquid interface of evaporating droplets. In addition, an optical interferometry technique is used to quantify and characterize the deposited patterns. Depending on the substrate temperature, three distinctive deposition patterns are observed: a nearly uniform coverage pattern, a "dual-ring" pattern, and multiple rings corresponding to "stick-slip" pattern. At all substrate temperatures, the internal flow within the drop builds a ringlike cluster of the solute on the top region of drying droplets, which is found essential for the formation of the secondary ring deposition onto the substrate for the deposits with the "dual-ring" pattern. The size of the secondary ring is found to be dependent on the substrate temperature. For the deposits with the rather uniform coverage pattern, the ringlike cluster of the solute does not deposit as a distinct secondary ring; instead, it is deformed by the contact line depinning. In the case of the "stick-slip" pattern, the internal flow behavior is complex and found to be vigorous with rapid circulating flow which appears near the edge of the drop.

  3. The Effects of Abdominal Hollowing in Lower-limb PNF Pattern Training on the Activation of Contralateral Muscles.

    Science.gov (United States)

    Yoo, Byungho; Park, Hankyu; Heo, Kwangjin; Lee, Joongsook; Lee, Jaeseok; Oh, Taeyoung; Han, Dongwook

    2013-10-01

    [Purpose] The purpose of this study was to determine the effects of abdominal hollowing during lower-limb proprioceptive neuromuscular facilitation (PNF) training on the activation of contralateral muscles. [Subjects] Twenty male college students without symptoms or signs of muscular or nervous disease participated in this experiment after signing a consent form. [Methods] All the subjects were measured with electromyography (EMG) in a muscle activation test before and after abdominal hollowing. In the PNF program, the lower-limb pattern of PNF training, was maintained for 5 seconds, followed by a 2-minute break. This was repeated three times. The resting time between sets was 30 minutes. Surface EMG (Keypoint, Medtronic Inc., USA) was used for the measurements, and the highest value of three measurements was used in the analysis. [Result] The results revealed a significant change in the muscular activation of the opposite-side lower limbs. The muscular activations of the vastus lateralis, tibialis anterior, semitendinosus and gastrocnemius were increased significantly after the abdominal hollowing. [Conclusion] The findings suggest that abdominal hollowing in PNF pattern training can be effective at promoting muscular activation of the contralateral muscles. To promote muscular activation of the opposite side in lower-limb PNF pattern training, abdominal hollowing should be considered to improve the effect of PNF pattern training.

  4. Maximum isometric knee flexor and extensor muscle contractions: normal patterns of torque versus time.

    Science.gov (United States)

    Murray, M P; Baldwin, J M; Gardner, G M; Sepic, S B; Downs, W J

    1977-06-01

    Isometric torque of the knee flexor and extensor muscles were recorded for 5 seconds at three knee joint positions. The subjects included healthy men in age groups from 20 to 35 and 45 to 65 years of age. The amplitudes and duration of peak torque and the time to peak torque were measured for each contraction. Peak torque was usually maintaned less than 0.1 second and never longer than 0.9 second. At each of the three angles, the mean extensor muscle torque was higher than the mean flexor muscle torque in both age groups, and the mean torque for both muscle group was higher among the younger than among the older man. The highest average torque was recorded at the knee angle of 60 degrees for the extensor muscles and 45 degrees for the flexor muscles, but this was not always a stereotyped response either for a given individual or among individuals.

  5. Upper trapezius muscle activity patterns during repetitive manual material handling and work with with a computer mouse.

    Science.gov (United States)

    Jensen, C; Finsen, L; Hansen, K; Christensen, H

    1999-10-01

    Firstly, upper trapezius EMG activity patterns were recorded on the dominant side of 6 industrial production workers and on the side operating a computer mouse of 14 computer-aided design (CAD) operators to study differences in acute muscular response related to the repetitiveness of the exposure. The work tasks were performed with median arm movement frequencies ranging from 5 min(-1) to 13 min(-1) and were characterized by work cycle times ranging from less than 30 sec to several days. However, the static and median EMG levels and EMG gap frequencies were similar for all work tasks indicating that shoulder muscle loads may be unaffected by large variations in arm movement frequencies and work cycle times. An exposure variation analyses (EVA) showed that the EMG activity patterns recorded during production work were more repetitive than during CAD work, whereas CAD work was associated with more static muscle activity patterns, both may be associated with a risk of developing musculoskeletal symptoms. Secondly, upper trapezius EMG activity patterns recorded on the mouse side of the CAD operators were compared with those recorded on the non-mouse side to study differences in muscular responses potentially related to the risk of developing shoulder symptoms which were more prevalent on the mouse side. The number of EMG gaps on the mouse side were significantly lower than the values for the upper trapezius on the non-mouse side indicating that more continuous activity was present in the upper trapezius muscle on the mouse side and EVA analyses showed a more repetitive muscle activity pattern on the mouse side. These findings may be of importance to explain differences in the prevalence of shoulder symptoms.

  6. The effect of ECG interference on pattern-recognition-based myoelectric control for targeted muscle reinnervated patients.

    Science.gov (United States)

    Hargrove, Levi; Zhou, Ping; Englehart, Kevin; Kuiken, Todd A

    2009-09-01

    Targeted muscle reinnervation has been introduced as an effective neural machine interface. In the case of a shoulder disarticulation patient, an effective site for a nerve transfer involves the pectoralis muscles, as these perform little useful function with a missing limb. Consequently, the myoelectric signals measured from the reinnervated muscles may be corrupted by a large amount of ECG interference. This paper investigates the effect of ECG upon the accuracy of a pattern-classification-based scheme for myoelectric control of powered upper limb prostheses. The results suggest that ECG interference, at levels typically encountered in a clinical measurement, has little effect upon classification accuracy, but can affect the estimate of myoelectric activity used to convey the velocity of motion (commonly referred to as proportional control). High-pass filtering at approximately 100 Hz appears to effectively mitigate the effect of ECG interference.

  7. Pattern formation and self-organization in plasmas interacting with surfaces

    Science.gov (United States)

    Trelles, Juan Pablo

    2016-10-01

    Pattern formation and self-organization are fascinating phenomena commonly observed in diverse types of biological, chemical and physical systems, including plasmas. These phenomena are often responsible for the occurrence of coherent structures found in nature, such as recirculation cells and spot arrangements; and their understanding and control can have important implications in technology, e.g. from determining the uniformity of plasma surface treatments to electrode erosion rates. This review comprises theoretical, computational and experimental investigations of the formation of spatiotemporal patterns that result from self-organization events due to the interaction of low-temperature plasmas in contact with confining or intervening surfaces, particularly electrodes. The basic definitions associated to pattern formation and self-organization are provided, as well as some of the characteristics of these phenomena within natural and technological contexts, especially those specific to plasmas. Phenomenological aspects of pattern formation include the competition between production/forcing and dissipation/transport processes, as well as nonequilibrium, stability, bifurcation and nonlinear interactions. The mathematical modeling of pattern formation in plasmas has encompassed from theoretical approaches and canonical models, such as reaction-diffusion systems, to drift-diffusion and nonequilibrium fluid flow models. The computational simulation of pattern formation phenomena imposes distinct challenges to numerical methods, such as high sensitivity to numerical approximations and the occurrence of multiple solutions. Representative experimental and numerical investigations of pattern formation and self-organization in diverse types of low-temperature electrical discharges (low and high pressure glow, dielectric barrier and arc discharges, etc) in contact with solid and liquid electrodes are reviewed. Notably, plasmas in contact with liquids, found in diverse

  8. Task-dependent spatial distribution of neural activation pattern in human rectus femoris muscle.

    Science.gov (United States)

    Watanabe, Kohei; Kouzaki, Motoki; Moritani, Toshio

    2012-04-01

    Compartmentalization of skeletal muscle by multiple motor nerve branches, named as neuromuscular compartment (NMC), has been demonstrated in animals as well as humans. While different functional roles among individual NMCs were reported in the animal studies, no studies have clarified the region-specific functional role within a muscle related with NMCs arrangement in human skeletal muscle. It was reported that the rectus femoris (RF) muscle is innervated by two nerve branches attached at proximal and distal parts of the muscle. The purpose of the present study is to clarify the possible region-specific functional role in the human RF muscle. Multi-channel surface electromyography (SEMG) were recorded from the RF muscle by using 128 electrodes during two different submaximal isometric contractions that the muscle contributes, i.e. isometric knee extension and hip flexion, at 20%, 40%, 60% and 80% of maximal voluntary contraction (MVC). Results indicated that the central locus activation for the amplitude map of SEMG during hip flexion located at more proximal region compared with that during knee extension. Significant higher normalized root mean square (RMS) values were observed at the proximal region during the hip flexion in comparison to those at middle and distal regions at 60% and 80% of MVC (pMVC (p<0.05). The results of the present study suggest possible region-specific functional role in the human RF muscle.

  9. Interfacial wave theory of pattern formation in solidification dendrites, fingers, cells and free boundaries

    CERN Document Server

    Xu, Jian-Jun

    2017-01-01

    This comprehensive work explores interfacial instability and pattern formation in dynamic systems away from the equilibrium state in solidification and crystal growth. Further, this significantly expanded 2nd edition introduces and reviews the progress made during the last two decades. In particular, it describes the most prominent pattern formation phenomena commonly observed in material processing and crystal growth in the framework of the previously established interfacial wave theory, including free dendritic growth from undercooled melt, cellular growth and eutectic growth in directional solidification, as well as viscous fingering in Hele-Shaw flow. It elucidates the key problems, systematically derives their mathematical solutions by pursuing a unified, asymptotic approach, and finally carefully examines these results by comparing them with the available experimental results. The asymptotic approach described here will be useful for the investigation of pattern formation phenomena occurring in a much b...

  10. Impact of degree mixing pattern on consensus formation in social networks

    Science.gov (United States)

    Liu, Xiao Fan; Tse, Chi Kong

    The consensus formation process in a social network is affected by a number of factors. This paper studies how the degree mixing pattern of a social network affects the consensus formation process. A social network of more than 50,000 nodes was sampled from the online social services website Twitter. Nodes in the Twitter user network are grouped by their in-degrees and out-degrees. A degree mixing correlation is proposed to measure the randomness of the mixing pattern for each degree group. The DeGroot model is used to simulate the consensus formation processes in the network. Simulation suggests that the non-random degree mixing pattern of social networks can slow down the rate of consensus.

  11. A Theoretical Model of Jigsaw-Puzzle Pattern Formation by Plant Leaf Epidermal Cells.

    Science.gov (United States)

    Higaki, Takumi; Kutsuna, Natsumaro; Akita, Kae; Takigawa-Imamura, Hisako; Yoshimura, Kenji; Miura, Takashi

    2016-04-01

    Plant leaf epidermal cells exhibit a jigsaw puzzle-like pattern that is generated by interdigitation of the cell wall during leaf development. The contribution of two ROP GTPases, ROP2 and ROP6, to the cytoskeletal dynamics that regulate epidermal cell wall interdigitation has already been examined; however, how interactions between these molecules result in pattern formation remains to be elucidated. Here, we propose a simple interface equation model that incorporates both the cell wall remodeling activity of ROP GTPases and the diffusible signaling molecules by which they are regulated. This model successfully reproduces pattern formation observed in vivo, and explains the counterintuitive experimental results of decreased cellulose production and increased thickness. Our model also reproduces the dynamics of three-way cell wall junctions. Therefore, this model provides a possible mechanism for cell wall interdigitation formation in vivo.

  12. On the dynamics of Liesegang-type pattern formation in a gaseous system

    Science.gov (United States)

    Ramírez-Álvarez, Elizeth; Montoya, Fernando; Buhse, Thomas; Rios-Herrera, Wady; Torres-Guzmán, José; Rivera, Marco; Martínez-Mekler, Gustavo; Müller, Markus F.

    2016-01-01

    Liesegang pattern formations are widely spread in nature. In spite of a comparably simple experimental setup under laboratory conditions, a variety of spatio-temporal structures may arise. Presumably because of easier control of the experimental conditions, Liesegang pattern formation was mainly studied in gel systems during more than a century. Here we consider pattern formation in a gas phase, where beautiful but highly complex reaction-diffusion-convection dynamics are uncovered by means of a specific laser technique. A quantitative analysis reveals that two different, apparently independent processes, both highly correlated and synchronized across the extension of the reaction cloud, act on different time scales. Each of them imprints a different structure of salt precipitation at the tube walls. PMID:27025405

  13. Wavelength Analysis of Interface between Two Miscible Solutions Observed in Formation of Fractal Pattern

    Science.gov (United States)

    Shimokawa, Michiko; Takami, Toshiya

    2014-04-01

    When a droplet of a higher-density solution (HDS) is placed on top of a lower-density solution (LDS), the HDS draws a fractal pattern on the surface of the LDS. Before the fractal pattern is formed, a stick-like pattern with a periodic structure emerges in a region surrounding the surface pattern due to interfacial instability. We experimentally measure the wavelength of this stick-like pattern. The wavelength increases with the volume of the HDS and is independent of the viscosities of the two solutions. To understand the stick generation, we propose a model of miscible viscous fingering whose boundary conditions are similar to those of the experiments. The wavelength obtained from the model agrees with the experimentally obtained wavelength. The formation of the fractal pattern is discussed by comparing it with the viscous fingering.

  14. Pattern formation in directional solidification under shear flow. I. Linear stability analysis and basic patterns.

    Science.gov (United States)

    Marietti, Y; Debierre, J M; Bock, T M; Kassner, K

    2001-06-01

    An asymptotic interface equation for directional solidification near the absolute stability limit is extended by a nonlocal term describing a shear flow parallel to the interface. In the long-wave limit considered, the flow acts destabilizing on a planar interface. Moreover, linear stability analysis suggests that the morphology diagram is modified by the flow near onset of the Mullins-Sekerka instability. Via numerical analysis, the bifurcation structure of the system is shown to change. Besides the known hexagonal cells, structures consisting of stripes arise. Due to its symmetry-breaking properties, the flow term induces a lateral drift of the whole pattern, once the instability has become active. The drift velocity is measured numerically and described analytically in the framework of a linear analysis. At large flow strength, the linear description breaks down, which is accompanied by a transition to flow-dominated morphologies which is described in the following paper. Small and intermediate flows lead to increased order in the lattice structure of the pattern, facilitating the elimination of defects. Locally oscillating structures appear closer to the instability threshold with flow than without.

  15. The Intersection of Theory and Application in Elucidating Pattern Formation in Developmental Biology.

    Science.gov (United States)

    Othmer, Hans G; Painter, Kevin; Umulis, David; Xue, Chuan

    2009-01-01

    We discuss theoretical and experimental approaches to three distinct developmental systems that illustrate how theory can influence experimental work and vice-versa. The chosen systems - Drosophila melanogaster, bacterial pattern formation, and pigmentation patterns - illustrate the fundamental physical processes of signaling, growth and cell division, and cell movement involved in pattern formation and development. These systems exemplify the current state of theoretical and experimental understanding of how these processes produce the observed patterns, and illustrate how theoretical and experimental approaches can interact to lead to a better understanding of development. As John Bonner said long ago'We have arrived at the stage where models are useful to suggest experiments, and the facts of the experiments in turn lead to new and improved models that suggest new experiments. By this rocking back and forth between the reality of experimental facts and the dream world of hypotheses, we can move slowly toward a satisfactory solution of the major problems of developmental biology.'

  16. The mechanism of Turing pattern formation in a positive feedback system with cross diffusion

    Science.gov (United States)

    Yang, Xiyan; Liu, Tuoqi; Zhang, Jiajun; Zhou, Tianshou

    2014-03-01

    In this paper, we analyze a reaction-diffusion (R-D) system with a double negative feedback loop and find cases where self diffusion alone cannot lead to Turing pattern formation but cross diffusion can. Specifically, we first derive a set of sufficient conditions for Turing instability by performing linear stability analysis, then plot two bifurcation diagrams that specifically identify Turing regions in the parameter phase plane, and finally numerically demonstrate representative Turing patterns according to the theoretical predictions. Our analysis combined with previous studies actually implies an interesting fact that Turing patterns can be generated not only in a class of monostable R-D systems where cross diffusion is not necessary but also in a class of bistable R-D systems where cross diffusion is necessary. In addition, our model would be a good candidate for experimentally testing Turing pattern formation from the viewpoint of synthetic biology.

  17. Performance analysis and optimal design for well patterns in anisotropic formations

    Institute of Scientific and Technical Information of China (English)

    Liu Yuetian

    2008-01-01

    The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation,fluid flow analysis,and reservoir development concepts.Anisotropy of permeability has reconstructive effects on well patterns.The originally designed flooding units are broken up,and new pattern units are made up of the wells that belong to different original units.The behavior possesses strong randomness,and leads to a complicated relationship among the injection and production wells,and unpredictable productivity of the formations.To prevent the break-up of well patterns,well lines should be either parallel or perpendicular to the maximum principal direction of the anisotropic permeability(i.e.the fracture direction).To optimize the development effects of anisotropic formations,the latitudinal and longitudinal well spacing of the well network are calculated from the principal values of the anisotropic permeability.

  18. Flight and seizure motor patterns in Drosophila mutants: simultaneous acoustic and electrophysiological recordings of wing beats and flight muscle activity.

    Science.gov (United States)

    Iyengar, Atulya; Wu, Chun-Fang

    2014-01-01

    Abstract Tethered flies allow studies of biomechanics and electrophysiology of flight control. We performed microelectrode recordings of spikes in an indirect flight muscle (the dorsal longitudinal muscle, DLMa) coupled with acoustic analysis of wing beat frequency (WBF) via microphone signals. Simultaneous electrophysiological recording of direct and indirect flight muscles has been technically challenging; however, the WBF is thought to reflect in a one-to-one relationship with spiking activity in a subset of direct flight muscles, including muscle m1b. Therefore, our approach enables systematic mutational analysis for changes in temporal features of electrical activity of motor neurons innervating subsets of direct and indirect flight muscles. Here, we report the consequences of specific ion channel disruptions on the spiking activity of myogenic DLMs (firing at ∼5 Hz) and the corresponding WBF (∼200 Hz). We examined mutants of the genes enconding: 1) voltage-gated Ca(2+) channels (cacophony, cac), 2) Ca(2+)-activated K(+) channels (slowpoke, slo), and 3) voltage-gated K(+) channels (Shaker, Sh) and their auxiliary subunits (Hyperkinetic, Hk and quiver, qvr). We found flight initiation in response to an air puff was severely disrupted in both cac and slo mutants. However, once initiated, slo flight was largely unaltered, whereas cac displayed disrupted DLM firing rates and WBF. Sh, Hk, and qvr mutants were able to maintain normal DLM firing rates, despite increased WBF. Notably, defects in the auxiliary subunits encoded by Hk and qvr could lead to distinct consequences, that is, disrupted DLM firing rhythmicity, not observed in Sh. Our mutant analysis of direct and indirect flight muscle activities indicates that the two motor activity patterns may be independently modified by specific ion channel mutations, and that this approach can be extended to other dipteran species and additional motor programs, such as electroconvulsive stimulation-induced seizures.

  19. Catalase overexpression in aortic smooth muscle prevents pathological mechanical changes underlying abdominal aortic aneurysm formation.

    Science.gov (United States)

    Maiellaro-Rafferty, Kathryn; Weiss, Daiana; Joseph, Giji; Wan, William; Gleason, Rudolph L; Taylor, W Robert

    2011-08-01

    The causality of the associations between cellular and mechanical mechanisms of abdominal aortic aneurysm (AAA) formation has not been completely defined. Because reactive oxygen species are established mediators of AAA growth and remodeling, our objective was to investigate oxidative stress-induced alterations in aortic biomechanics and microstructure during subclinical AAA development. We investigated the mechanisms of AAA in an angiotensin II (ANG II) infusion model of AAA in apolipoprotein E-deficient (apoE(-/-)) mice that overexpress catalase in vascular smooth muscle cells (apoE(-/-)xTg(SMC-Cat)). At baseline, aortas from apoE(-/-)xTg(SMC-Cat) exhibited increased stiffness and the microstructure was characterized by 50% more collagen content and less elastin fragmentation. ANG II treatment for 7 days in apoE(-/-) mice altered the transmural distribution of suprarenal aortic circumferential strain (quantified by opening angle, which increased from 130 ± 1° at baseline to 198 ± 8° after 7 days of ANG II treatment) without obvious changes in the aortic microstructure. No differences in aortic mechanical behavior or suprarenal opening angle were observed in apoE(-/-)xTg(SMC-Cat) after 7 days of ANG II treatment. These data suggest that at the earliest stages of AAA development H(2)O(2) is functionally important and is involved in the control of local variations in remodeling across the vessel wall. They further suggest that reduced elastin integrity at baseline may predispose the abdominal aorta to aneurysmal mechanical remodeling.

  20. Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

    Directory of Open Access Journals (Sweden)

    Huang Stephanie

    2012-08-01

    Full Text Available Abstract Background Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user’s nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. Methods We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. Results We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Conclusion Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee’s nervous system.

  1. Insular dentin formation pattern in human odontogenesis in relation to the scalloped dentino-enamel junction.

    Science.gov (United States)

    Radlanski, Ralf J; Renz, Herbert

    2007-01-01

    This study is a first report on the modality of early dentin formation in respect to the scalloped pattern of the dentino-enamel junction (DEJ). We applied scanning electron microscopy (SEM), transmission electron microscopy (TEM), histological serial sections, and three-dimensional (3D) reconstructions. TEM and SEM showed scallops and secondary scallops on the DEJ of deciduous dental primordia and on deciduous teeth with the enamel cap removed. This peculiar outline of the DEJ requires a specific dentin formation pattern; histological sections showed that dentin formation began at the brims of the scallops, seen as triangular spikes in serial sections. The dentin formation front was not uniform; instead, it was characterized by multiple, insular forming centers, as revealed by our 3D reconstructions. As thicker dentin layers formed, the islands became confluent. Factors are discussed, which may lead to crimpling of the inner enamel epithelium, and maintained as the scalloped pattern of the DEJ develops. Signaling patterns in accordance with the insular dentin formation are unknown so far.

  2. Hardware format pattern banks for the Associative memory boards in the ATLAS Fast Tracker Trigger System

    CERN Document Server

    Grewcoe, Clay James

    2014-01-01

    The aim of this project is to streamline and update the process of encoding the pattern bank to hardware format in the Associative memory board (AM) of the Fast Tracker (FTK) for the ATLAS detector. The encoding is also adapted to Gray code to eliminate possible misreadings in high frequency devices such as this one, ROOT files are used to store the pattern banks because of the compression utilized in ROOT.

  3. Topological analysis of the formation of Jet-Wake flow pattern in centrifugal impeller channel

    Institute of Scientific and Technical Information of China (English)

    ZHENG Qun; LIU Shun-long

    2004-01-01

    Topological analyses are carried out for the numerical results of internal flow field in centrifugal impeller. Topological rules of the singular point characteristics of the limiting streamline are derived and used to determine three dimensional separation patterns in centrifugal impeller and to verify the numerical results. The results reveal that the wake is saddle to nodal closed separation and the formation, its onset point and its developing process of Jet-Wake Flow pattern in centrifugal impeller are presented in this paper.

  4. Pattern Formation in a Vibrated Granular Layer on an Inclined Base

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-Dong; MIAO Guo-Qing

    2008-01-01

    We carry out the simulations of pattern formation in a two-dimensional vibrated granular layer on an inclined base by molecular dynamics.It is found that the maximum amplitude of the pattern is greater at the lower part than at the higher part of the base,and is proportional to the thickness of the layer.Meanwhile,the wavelength varies non-monotonically as the inclined angle of the base is increased.

  5. MRI findings, patterns of disease distribution, and muscle fat fraction calculation in five patients with Charcot-Marie-Tooth type 2 F disease

    Energy Technology Data Exchange (ETDEWEB)

    Gaeta, Michele; Mileto, Achille; Minutoli, Fabio; Settineri, Nicola; Donato, Rocco; Ascenti, Giorgio; Blandino, Alfredo [Policlinico ' ' G. Martino' ' , Dipartimento di Scienze Radiologiche, Messina (Italy); Mazzeo, Anna; Di Leo, Rita [Policlinico ' ' G. Martino' ' , Dipartimento di Neuroscienze, Scienze Psichiatriche ed Anestesiologiche, Messina (Italy)

    2012-05-15

    To describe the magnetic resonance imaging (MRI) pattern of muscle involvement and disease progression in five patients with late-onset Charcot-Marie-Tooth (CMT) disease type 2 F, due to a previously unknown mutation. Five patients (three males, two females) underwent MRI of the lower limbs to define the pattern of muscle involvement and evaluate the muscle fat fraction (MFF) of residual thigh muscle with gradient-echo (GRE) dual-echo dual-flip angle technique. Evaluation of fatty infiltration both by visual inspection and MFF calculation was performed. A proximal-to-distal gradient of muscle involvement was depicted in male patients with extensive muscle wasting of lower legs, less severe impairment of distal thigh muscles, and sparing of proximal thigh muscles. A peculiar phenotype finding was that no or only slight muscle abnormalities could be found in the two female patients. We described the pattern of muscle involvement and disease progression in a family with CMT disease type 2 F. GRE dual-echo dual-flip angle MRI technique is a valuable technique to obtain a rapid quantification of MFF. (orig.)

  6. Pattern Formation inside a Rotating Cylinder Partially Filled with Liquid and Granular Medium

    Directory of Open Access Journals (Sweden)

    Veronika Dyakova

    2014-01-01

    Full Text Available The paper focuses on the experimental study of the dynamics of liquid and granular medium in a rapidly rotating horizontal cylinder. In the cavity frame gravity field performs rotation and produces oscillatory liquid flow, which is responsible for the series of novel effects; the problem corresponds to “vibrational mechanics”—generation of steady flows and patterns by oscillating force field. The paper presents the initial results of experimental study of a novel pattern formation effect which is observed at the interface between fluid and sand and which takes the form of ripples extended along the axis of rotation. The initial results of experimental research of a novel effect of pattern formation at the interface between fluid and sand in the form of ripples extended along the axis of rotation are presented. The spatial period of the patterns is studied in dependence on liquid volume, viscosity, and rotation rate. The experimental study of long time dynamics of pattern formation manifests that regular ripples transform into a series of dunes within a few minutes or dozens of minutes. The variety of patterns is determined by the interaction of two types of liquid flows induced by gravity: oscillatory and steady azimuthal flows near the sand surface.

  7. Patterns of Hamstring Muscle Tears in the General Population: A Systematic Review.

    Directory of Open Access Journals (Sweden)

    Barbara Kuske

    Full Text Available Hamstring tears are well recognised in the sporting population. Little is known about these injuries in the general population.Evaluating the rates, patterns and risk factors of non-sporting hamstring tears, compared to sporting related hamstring tears.MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials (1989-2015.Studies reporting patients with a grade 2 or 3 hamstring muscle tear, identified clinically, confirmed by MRI imaging or direct visualisation during surgical exploration.144 sets of linked data were extracted for analysis. Most injuries were in males (81.3%, where mean age at injury was lower (30.2, 95% CI 29.1-31.3 than in females (35.4, 95% CI 32.4-38.4 p = 0.06. Key differences were found in the proportion of non-sporting injuries in patients under and over the age 40 (p = 0.001. The proportion of non-sporting injuries was significantly higher in females compared to males (25.9% female non-sporting injuries, versus 8.5% male; p = 0.02. Avulsions were more frequently reported in non-sporting activities (70.5%. The proportion of such injuries was notably higher in females, though this failed to meet significance (p = 0.124. Grouped by age category a bimodal distribution was noted, with the proportion of avulsions greater in younger (age 40 (p = 0.008. 86.8% of patients returned to pre-injury activity levels with a similar frequency across all study variables; age, activity (sporting vs non-sporting and injury type (avulsion vs tear.This review highlights a proportion of adults suffering grade 2 or 3 hamstring injuries from activities other than the classic sports trauma. The majority of these non-sporting injuries were avulsion injuries that clustered in older female and skeletally immature patients suggesting a potential link to bone mineral density.

  8. Patterns of Hamstring Muscle Tears in the General Population: A Systematic Review.

    Science.gov (United States)

    Kuske, Barbara; Hamilton, David F; Pattle, Sam B; Simpson, A Hamish R W

    2016-01-01

    Hamstring tears are well recognised in the sporting population. Little is known about these injuries in the general population. Evaluating the rates, patterns and risk factors of non-sporting hamstring tears, compared to sporting related hamstring tears. MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials (1989-2015). Studies reporting patients with a grade 2 or 3 hamstring muscle tear, identified clinically, confirmed by MRI imaging or direct visualisation during surgical exploration. 144 sets of linked data were extracted for analysis. Most injuries were in males (81.3%), where mean age at injury was lower (30.2, 95% CI 29.1-31.3) than in females (35.4, 95% CI 32.4-38.4) p = 0.06. Key differences were found in the proportion of non-sporting injuries in patients under and over the age 40 (p = 0.001). The proportion of non-sporting injuries was significantly higher in females compared to males (25.9% female non-sporting injuries, versus 8.5% male; p = 0.02). Avulsions were more frequently reported in non-sporting activities (70.5%). The proportion of such injuries was notably higher in females, though this failed to meet significance (p = 0.124). Grouped by age category a bimodal distribution was noted, with the proportion of avulsions greater in younger (age 40) (p = 0.008). 86.8% of patients returned to pre-injury activity levels with a similar frequency across all study variables; age, activity (sporting vs non-sporting) and injury type (avulsion vs tear). This review highlights a proportion of adults suffering grade 2 or 3 hamstring injuries from activities other than the classic sports trauma. The majority of these non-sporting injuries were avulsion injuries that clustered in older female and skeletally immature patients suggesting a potential link to bone mineral density.

  9. Temporal Pattern of the Repeated Bout Effect of Eccentric Exercise on Delayed-Onset Muscle Soreness

    Science.gov (United States)

    Cleary, Michelle A.; Kimura, Iris F.; Sitler, Michael R.; Kendrick, Zebulon V.

    2002-01-01

    Objective: To determine the temporal pattern of the repeated bout effect of eccentric exercise on perceived pain and muscular tenderness associated with delayed-onset muscle soreness (DOMS). Design and Setting: Subjects completed 2 identical eccentric exercise bouts separated by 6, 7, 8, or 9 weeks. The experiment was conducted in a biokinetics research laboratory. Subjects: Sixteen male and 15 female untrained subjects (age = 24.59 ± 4.42 years, height = 171.71 ± 7.81 cm, weight = 73.00 ± 11.20 kg). Measurements: Two physiologic characteristics of DOMS were measured immediately before and 0, 24, 48, and 72 hours after each eccentric exercise bout. Perceived pain was measured using a visual analog scale (VAS), and muscular tenderness was measured using a punctate tenderness gauge (PTG). Results: Two 4 × 2 × 5 (group × bout × time) analyses of variance with repeated measures on the bout and time factors were performed on the VAS and PTG data. Significant (P < .05) main effects were found for group, bout, and time for the VAS and the PTG data. No significant interactions were detected. Post hoc analysis revealed significantly less perceived pain for the 9-week group than the 8-week group. The 7-week group had significantly less and the 8-week group had significantly more muscular tenderness than any other group. Perceived pain and muscular tenderness were significantly less after exercise bout 2 than after exercise bout 1. All subjects had significantly less perceived pain and muscular tenderness pre-exercise than 0 and 24 hours after the eccentric exercise bouts. Conclusions: An effective prophylaxis for perceived pain and muscular tenderness associated with DOMS is the performance of an eccentric exercise bout 6 to 9 weeks before a similar exercise bout. PMID:12937441

  10. Pattern formation in reaction-diffusion systems: From spiral waves to turbulence

    Science.gov (United States)

    Davidsen, Joern

    2009-05-01

    Almost all systems we encounter in nature possess some sort of form or structure. In many cases, the structures arise from an initially unstructured state without the action of an agent that predetermines the pattern. Such self-organized structures emerge from cooperative interactions among the constituents of the system and often exhibit properties that are distinct from those of their constituent elements or molecules. For example, chemical waves in reaction-diffusion systems are at the core of a huge variety of physical, chemical, and biological processes. In (quasi) two-dimensional situations, spiral wave patterns are especially prevalent and determine the characteristics of processes such as surface catalytic oxidation reactions, contraction of the heart muscle, and various signaling mechanisms in biological systems. In this talk, I will review and discuss recent theoretical and experimental results regarding the dynamics, properties and stability of spiral waves and their three-dimensional analog (scroll waves). Special emphasis will be given to synchronization defect lines which generically arise in complex-oscillatory media, and the phenomenon of defect-mediated turbulence or filament turbulence where the dynamics of a pattern is dominated by the rapid motion, nucleation, and annihilation of spirals or scroll waves, respectively. The latter is of direct relevance in the context of ventricular fibrillation - a turbulent electrical wave activity that destroys the coherent contraction of the ventricular muscle and its main pumping function leading to sudden cardiac death.

  11. Pattern Formation in a Predator-Prey Model with Both Cross Diffusion and Time Delay

    Directory of Open Access Journals (Sweden)

    Boli Xie

    2014-01-01

    Full Text Available A predator-prey model with both cross diffusion and time delay is considered. We give the conditions for emerging Turing instability in detail. Furthermore, we illustrate the spatial patterns via numerical simulations, which show that the model dynamics exhibits a delay and diffusion controlled formation growth not only of spots and stripe-like patterns, but also of the two coexist. The obtained results show that this system has rich dynamics; these patterns show that it is useful for the diffusive predation model with a delay effect to reveal the spatial dynamics in the real model.

  12. Design of a diffractive optical element for pattern formation in a bilingual virtual keyboard

    Science.gov (United States)

    Manouchehri, Sohrab; Rahimi, Mojtaba; Oboudiat, Mohammad

    2016-03-01

    Pattern formation is one of the many applications of diffractive optical elements (DOEs) for display. Since DOEs have lightweight and slim nature compared to other optical devices, using them as image projection device in virtual keyboards is suggested. In this paper, we present an approach to designing elements that produce distinct intensity patterns, in the far field, for two wavelengths. These two patterns are images of bilingual virtual keyboard. To achieve this with DOEs is not simple, as they are inherently wavelength specific. Our technique is based on phase periodic characteristic of wavefront using iterative algorithm to design the phase profiles.

  13. Kir2.1 regulates rat smooth muscle cell proliferation, migration, and post-injury carotid neointimal formation

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Yong; Tang, Chengchun, E-mail: tangchengchun@medmail.com.cn; Wang, Qingjie; Wang, Dong; Yan, Gaoliang; Zhu, Boqian

    2016-09-02

    Phenotype switching of vascular smooth muscle cells (VSMC) from the contractile type to the synthetic type is a hallmark of vascular disorders such as atherosclerosis and restenosis after angioplasty. Inward rectifier K{sup +} channel 2.1 (Kir2.1) has been identified in VSMC. However, whether it plays a functional role in regulating cellular transformation remains obscure. In this study, we evaluated the role of Kir2.1 on VSMC proliferation, migration, phenotype switching, and post-injury carotid neointimal formation. Kir2.1 knockdown significantly suppressed platelet-derived growth factor BB-stimulated rat vascular smooth muscle cells (rat-VSMC) proliferation and migration. Deficiency in Kir2.1 contributed to the restoration of smooth muscle α-actin, smooth muscle 22α, and calponin and to a reduction in osteopontin expression in rat-VSMC. Moreover, the in vivo study showed that rat-VSMC switched to proliferative phenotypes and that knockdown of Kir2.1 significantly inhibited neointimal formation after rat carotid injury. Kir2.1 may be a potential therapeutic target in the treatment of cardiovascular diseases, such as atherosclerosis and restenosis following percutaneous coronary intervention.

  14. Motor unit recruitment patterns 2: the influence of myoelectric intensity and muscle fascicle strain rate.

    Science.gov (United States)

    Hodson-Tole, Emma F; Wakeling, James M

    2008-06-01

    To effectively meet the force requirements of a given movement an appropriate number and combination of motor units must be recruited between and within muscles. Orderly recruitment of motor units has been shown to occur in a wide range of skeletal muscles, however, alternative strategies do occur. Faster motor units are better suited to developing force rapidly, and produce higher mechanical power with greater efficiency at faster shortening strain rates than slower motor units. As the frequency content of the myoelectric signal is related to the fibre type of the active motor units, we hypothesised that, in addition to an association between myoelectric frequency and intensity, there would be a significant association between muscle fascicle shortening strain rate and myoelectric frequency content. Myoelectric and sonomicrometric data were collected from the three ankle extensor muscles of the rat hind limb during walking and running. Myoelectric signals were analysed using wavelet transformation and principal component analysis to give a measure of the signal frequency content. Sonomicrometric signals were analysed to give measures of muscle fascicle strain and strain rate. The relationship between myoelectric frequency and both intensity and muscle fascicle strain rate was found to change across the time course of a stride, with differences also occurring in the strength of the associations between and within muscles. In addition to the orderly recruitment of motor units, a mechanical strategy of motor unit recruitment was therefore identified. Motor unit recruitment is therefore a multifactorial phenomenon, which is more complex than typically thought.

  15. Patterns of spatial and temporal visceral arch muscle development in the Mexican axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Ericsson, Rolf; Olsson, Lennart

    2004-08-01

    Vertebrate head development is a classical topic that has received renewed attention during the last decade. Most reports use one of a few model organisms (chicken, mouse, zebrafish) and have focused on molecular mechanisms and the role of the neural crest, while cranial muscle development has received less attention. Here we describe cranial muscle differentiation and morphogenesis in the Mexican axolotl, Ambystoma mexicanum. To determine the onset of differentiation we use antibodies against desmin and optical sectioning using confocal laser scanning microscopy on whole-mount immunostained embryos. This technique makes it possible to document the cranial muscle in three dimensions while keeping the specimens intact. Desmin expression starts almost simultaneously in the first, second, and third visceral arch muscles (as in other amphibians studied). Muscle anlagen divide up early into the different elements which constitute the larval cranial musculature. We extend and refine earlier findings, e.g., by documenting a clear division between interhyoideus and interhyoideus posterior. The timing of cranial muscle differentiation differs among vertebrate groups, but seems to be constant within each group. This study provides a morphological foundation for further studies of muscle cell fate and early differentiation.

  16. Intramuscular nerve distribution patterns of anterior forearm muscles in children: a guide for botulinum toxin injection.

    Science.gov (United States)

    Yang, Fangjiu; Zhang, Xiaoming; Xie, Xiadan; Yang, Shengbo; Xu, Yan; Xie, Peng

    2016-01-01

    Botulinum toxin (BoNT) can relieve muscle spasticity by blocking axon terminals acetylcholine release at the motor endplate (MEP) and is the safest and most effective agent for the treatment of muscle spasticity in children with cerebral palsy. In order to achieve maximum effect with minimum effective dose of BoNT, one needs to choose an injection site as near to the MEP zone as possible. This requires a detailed understanding about the nerve terminal distributions within the muscles targeted for BoNT injection. This study focuses on BoNT treatment in children with muscle spasms caused by cerebral palsy. Considering the differences between children and adults in anatomy, we used child cadavers and measured both the nerve entry points and nerve terminal sense zones in three deep muscles of the anterior forearm: flexor digitorum profundus (FDP), flexor pollicis longus (FPL), and pronator quadratus (PQ). We measured the nerve entry points by using the forearm midline as a reference and demonstrated intramuscular nerve terminal dense zones by using a modified Sihler's nerve staining technique. The locations of the nerve entry points and that of the nerve terminal dense zones in the muscles were compared. We found that all nerve entry points are away from the corresponding intramuscular nerve terminal dense zones. Simply selecting nerve entry points as the sites for BoNT injection may not be an optimal choice for best effects in blocking muscle spasm. We propose that the location of the nerve terminal dense zones in each individual muscle should be used as the optimal target sites for BoNT injection when treating muscle spasms in children with cerebral palsy.

  17. Multi-target trapping in constrained environments using gene regulatory network-based pattern formation

    Directory of Open Access Journals (Sweden)

    Xingguang Peng

    2016-10-01

    Full Text Available Inspired by the morphogenesis of biological organisms, gene regulatory network-based methods have been used in complex pattern formation of swarm robotic systems. In this article, obstacle information was embedded into the gene regulatory network model to make the robots trap targets with an expected pattern while avoiding obstacles in a distributed manner. Based on the modified gene regulatory network model, an implicit function method was adopted to represent the expected pattern which is easily adjusted by adding extra feature points. Considering environmental constraints (e.g. tunnels or gaps in which robots must adjust their pattern to conduct trapping task, a pattern adaptation strategy was proposed for the pattern modeler to adaptively adjust the expected pattern. Also to trap multiple targets, a splitting pattern adaptation strategy was proposed for diffusively moving targets so that the robots can trap each target separately with split sub-patterns. The proposed model and strategies were verified through a set of simulation with complex environmental constraints and non-consensus movements of targets.

  18. Asymptotic Analysis in a Gas-Solid Combustion Model with Pattern Formation

    Institute of Scientific and Technical Information of China (English)

    Claude-Michel BRAUNER; Lina HU; Luca LORENZI

    2013-01-01

    The authors consider a free interface problem which stems from a gas-solid model in combustion with pattern formation.A third-order,fully nonlinear,self-consistent equation for the flame front is derived.Asymptotic methods reveal that the interface approaches a solution to the Kuramoto-Sivashinsky equation.Numerical results which illustrate the dynamics are presented.

  19. Phase-field modeling of microstructural pattern formation in alloys and geological veins

    OpenAIRE

    Ankit, Kumar

    2016-01-01

    With the advent of high performance computing, the application areas of the phase-field method, traditionally used to numerically model the phase transformation in metals and alloys, have now spanned into geoscience. A systematic investigation of the two distinct scientific problems in consideration suggest a strong influence of interfacial energy on the natural and induced pattern formation in diffusion-controlled regime.

  20. Global bifurcation analysis and pattern formation in homogeneous diffusive predator-prey systems

    Science.gov (United States)

    Wang, Jinfeng; Wei, Junjie; Shi, Junping

    2016-02-01

    The dynamics of a general diffusive predator-prey system is considered. Existence and nonexistence of non-constant positive steady state solutions are shown to identify the ranges of parameters of spatial pattern formation. Bifurcations of spatially homogeneous and nonhomogeneous periodic solutions as well as non-constant steady state solutions are studied.

  1. Patterned electrospun nanofiber matrices via localized dissolution: potential for guided tissue formation.

    Science.gov (United States)

    Jia, Chao; Yu, Dou; Lamarre, Marven; Leopold, Philip L; Teng, Yang D; Wang, Hongjun

    2014-12-23

    With the assistance of an ink-jet printer, solvent (the "ink") can be controllably and reproducibly printed onto electrospun nanofiber meshes (the "paper") to generate various micropatterns and subsequently guide distinct cellular organization and phenotype expression. In combination with the nanofiber-assisted layer-by-layer cell assembly, the patterned electrospun meshes will define an instructive microenvironment for guided tissue formation.

  2. Transverse Mode Structure and Pattern Formation in Oxide Confined Vertical Cavity Semiconductor Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Choquette, K.D.; Geib, K.M.; Hegarty, S.P.; Hou, H.Q.; Huyet, G.; McInerney, J.G.; Porta, P.

    1999-07-06

    We analyze the transverse profiles of oxide-confined vertical cavity laser diodes as a function of aperture size. For small apertures we demonstrate that thermal lensing can be the dominant effect in determining the transverse resonator properties. We also analyze pattern formation in lasers with large apertures where we observe the appearance of tilted waves.

  3. Variation in brachial plexus formation, branching pattern and relation with major vessels

    Directory of Open Access Journals (Sweden)

    G. Anwer Khan

    2014-08-01

    Conclusion: The present study carried out on adult human cadavers revealed some rare variations in the formation, branching pattern and relations of the brachial plexus. These variations are of clinical significance for the surgeons, radiologists and the anesthesiologists. [Int J Res Med Sci 2014; 2(4.000: 1591-1594

  4. Collective motion of cells mediates segregation and pattern formation in co-cultures.

    Directory of Open Access Journals (Sweden)

    Elod Méhes

    Full Text Available Pattern formation by segregation of cell types is an important process during embryonic development. We show that an experimentally yet unexplored mechanism based on collective motility of segregating cells enhances the effects of known pattern formation mechanisms such as differential adhesion, mechanochemical interactions or cell migration directed by morphogens. To study in vitro cell segregation we use time-lapse videomicroscopy and quantitative analysis of the main features of the motion of individual cells or groups. Our observations have been extensive, typically involving the investigation of the development of patterns containing up to 200,000 cells. By either comparing keratocyte types with different collective motility characteristics or increasing cells' directional persistence by the inhibition of Rac1 GTP-ase we demonstrate that enhanced collective cell motility results in faster cell segregation leading to the formation of more extensive patterns. The growth of the characteristic scale of patterns generally follows an algebraic scaling law with exponent values up to 0.74 in the presence of collective motion, compared to significantly smaller exponents in case of diffusive motion.

  5. Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation

    Directory of Open Access Journals (Sweden)

    Sabrina G. Sobel

    2009-01-01

    Full Text Available Imperfect mixing is a concern in industrial processes, everyday processes (mixing paint, bread machines, and in understanding salt water-fresh water mixing in ecosystems. The effects of imperfect mixing become evident in the unstirred ferroin-catalyzed Belousov-Zhabotinsky reaction, the prototype for chemical pattern formation. Over time, waves of oxidation (high ferriin concentration, blue propagate into a background of low ferriin concentration (red; their structure reflects in part the history of mixing in the reaction vessel. However, it may be difficult to separate mixing effects from reaction effects. We describe a simpler model system for visualizing density-driven pattern formation in an essentially unmixed chemical system: the reaction of pale yellow Fe3+ with colorless SCN− to form the blood-red Fe(SCN2+ complex ion in aqueous solution. Careful addition of one drop of Fe(NO33 to KSCN yields striped patterns after several minutes. The patterns appear reminiscent of Rayleigh-Taylor instabilities and convection rolls, arguing that pattern formation is caused by density-driven mixing.

  6. SIMULATION OF ELECTRICAL FIELD FOR THE FORMATION MECHANISM OF BIRD'S NEST PATTERNED STRUCTURES BY ELECTROSPINNING

    Institute of Scientific and Technical Information of China (English)

    Xiang-yu Ye; Yi-ning Jin; Xiao-jun Huang; Lei Luo; Zhi-kang Xu

    2013-01-01

    In our previous work,it was found that large Bird's Nest patterned nanofibrous membranes can be simply electrospun from chlorinated polypropylene solution doped with an ionic liquid,and a plausible formation mechanism of Bird's Nest patterned architectures was proposed.Here,we use Ansoft Maxwell version 12 software (3D,electrostatic solver) to simulate the electrical field distribution of the electrospirming setup,and to clarify the rationality of proposed formation mechanism.Calculation results clearly show that the introduction of charged nanofibrous bundles would produce a similar patterned electrical field distribution,which definitely confirms the important role of surface residual charges.The proposed mechanism can be well extended to other polymer systems including polystyrene,poly(acrylonitrile-co-acrylic acid) and chitosan/poly(ethvlene oxide).

  7. The effect of the signalling scheme on the robustness of pattern formation in development

    KAUST Repository

    Kang, H.-W.

    2012-03-21

    Pattern formation in development is a complex process which involves spatially distributed signals called morphogens that influence gene expression and thus the phenotypic identity of cells. Usually different cell types are spatially segregated, and the boundary between them may be determined by a threshold value of some state variable. The question arises as to how sensitive the location of such a boundary is to variations in properties, such as parameter values, that characterize the system. Here, we analyse both deterministic and stochastic reaction-diffusion models of pattern formation with a view towards understanding how the signalling scheme used for patterning affects the variability of boundary determination between cell types in a developing tissue.

  8. Concurrent assessments of lower limb loading patterns, mechanical muscle strength and functional performance in ACL-patients - A cross-sectional study

    DEFF Research Database (Denmark)

    Holsgaard-Larsen, Anders; Jensen, C; Mortensen, N H M

    2014-01-01

    Full recovery in muscle strength and functional performance may not be achieved after ACL-injury. Aim: The aim of this study is to investigate loading patterns during jumping, muscle function and functional performance in ACL-reconstructed patients and to investigate the origin of between-limb...

  9. Initial and treatment induced changes to muscle activation patterns in patients with adolescent idiopathic scoliosis compared to the frontal plane spinal configuration as measured with surface electromyography

    Institute of Scientific and Technical Information of China (English)

    Raymond Wiegand

    2005-01-01

    PURPOSE:The purpose of this study is to report paraspinal muscle activity patterns in adolescent idiopathic scoliosis (AIS)patients in comparison to the frontal plane spinal configuration and to report changes to the muscle activity resulting from a multi-factorial treatment program that includes chiropractic manipulation.

  10. Patterns of Lower Limb Muscle Activity in Young Boys During a One Foot Static Balance Task.

    Science.gov (United States)

    Layne, Charles S.; Abraham, Lawrence D.

    1987-01-01

    This study of 10 seven- to nine-year-old boys was undertaken to determine the electromyographic activity of four muscles in the supporting leg during one foot static balancing. Results are presented and analyzed. (Author/MT)

  11. Upper extremity kinematics and muscle activation patterns in subjects with facioscapulohumeral dystrophy

    NARCIS (Netherlands)

    Bergsma, A.; Murgia, A.; Cup, E.H.C.; Verstegen, P.P.; Meijer, K.; Groot, I.J.M. de

    2014-01-01

    OBJECTIVE: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. DESIGN: Exploratory case-control study. SETTING: A movement laboratory. PARTICIPANTS: Subjects

  12. Upper Extremity Kinematics and Muscle Activation Patterns in Subjects With Facioscapulohumeral Dystrophy

    NARCIS (Netherlands)

    Bergsma, Arjen; Murgia, Alessio; Cup, Edith H.; Verstegen, Paul P.; Meijer, Kenneth; de Groot, Imelda J.

    Objective: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. Design: Exploratory case-control study. Setting: A movement laboratory. Participants: Subjects

  13. Upper Extremity Kinematics and Muscle Activation Patterns in Subjects With Facioscapulohumeral Dystrophy

    NARCIS (Netherlands)

    Bergsma, Arjen; Murgia, Alessio; Cup, Edith H.; Verstegen, Paul P.; Meijer, Kenneth; de Groot, Imelda J.

    2014-01-01

    Objective: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. Design: Exploratory case-control study. Setting: A movement laboratory. Participants: Subjects (N=

  14. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization.

    Science.gov (United States)

    Braun, Hans-Georg; Meyer, Evelyn

    2013-02-05

    The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO), molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness PEO molecules, n-alkylterminated (hydrophobic) PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups.

  15. Characteristic muscle activity patterns during gait initiation in the healthy younger and older adults.

    Science.gov (United States)

    Khanmohammadi, Roya; Talebian, Saeed; Hadian, Mohammad Reza; Olyaei, Gholamreza; Bagheri, Hossein

    2016-01-01

    It is thought that gait initiation (GI) might be an optimal task for identifying postural control deficiencies. Thus, the aim of this study was to clarify the strategies adopted by older subjects during this task. 16 healthy younger and 15 healthy older adults participated in the study. Subjects were instructed to begin forward stepping with their dominant limb in response to an auditory stimulus. The mean muscle activity, co-contraction index, and intra-subject coefficients of variation (intra-subject CVs) of dominant limb muscles in different phases of GI were measured. The level of association between the co-contraction index and intra-subject CV of muscles was also explored. This study showed that in the anticipatory phase, the younger group had larger amplitudes and more intra-subject CVs than older the group, particularly for the tibialis anterior muscle. However, the co-contraction index was greater in older subjects relative to younger subjects. During the weight transition phase, tibialis anterior, semitendinosus and vastus lateralis muscles of older adults had a lower amplitude as compared to younger adults. However, during the locomotor phase, the activity of tibialis anterior was greater in comparison to younger adults. Also, during this phase, similar to the anticipatory phase, the co-contraction index between tibialis anterior and gastrocnemius muscles was greater in older subjects relative to younger subjects. Additionally, the larger co-contraction index of some muscles was associated with smaller intra-subject CV. These findings suggest that muscle behaviors are altered with aging and older adults employ different strategies in the different phases of GI as compared to younger adults.

  16. Dynamic DTI (dDTI) shows differing temporal activation patterns in post-exercise skeletal muscles.

    Science.gov (United States)

    Rockel, Conrad; Akbari, Alireza; Kumbhare, Dinesh A; Noseworthy, Michael D

    2017-04-01

    To assess post-exercise recovery of human calf muscles using dynamic diffusion tensor imaging (dDTI). DTI data (6 directions, b = 0 and 400 s/mm(2)) were acquired every 35 s from seven healthy men using a 3T MRI, prior to (4 volumes) and immediately following exercise (13 volumes, ~7.5 min). Exercise consisted of 5-min in-bore repetitive dorsiflexion-eversion foot motion with 0.78 kg resistance. Diffusion tensors calculated at each time point produced maps of mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and signal at b = 0 s/mm(2) (S0). Region-of-interest (ROI) analysis was performed on five calf muscles: tibialis anterior (ATIB), extensor digitorum longus (EDL) peroneus longus (PER), soleus (SOL), and lateral gastrocnemius (LG). Active muscles (ATIB, EDL, PER) showed significantly elevated initial MD post-exercise, while predicted inactive muscles (SOL, LG) did not (p exercise EDL S0 relative to other muscles across the majority of time points (p exercise-induced changes between muscles. These differences are suggested to be related to differences in fiber composition.

  17. Exercise training alters DNA methylation patterns in genes related to muscle growth and differentiation in mice.

    Science.gov (United States)

    Kanzleiter, Timo; Jähnert, Markus; Schulze, Gunnar; Selbig, Joachim; Hallahan, Nicole; Schwenk, Robert Wolfgang; Schürmann, Annette

    2015-05-15

    The adaptive response of skeletal muscle to exercise training is tightly controlled and therefore requires transcriptional regulation. DNA methylation is an epigenetic mechanism known to modulate gene expression, but its contribution to exercise-induced adaptations in skeletal muscle is not well studied. Here, we describe a genome-wide analysis of DNA methylation in muscle of trained mice (n = 3). Compared with sedentary controls, 2,762 genes exhibited differentially methylated CpGs (P 5%, coverage >10) in their putative promoter regions. Alignment with gene expression data (n = 6) revealed 200 genes with a negative correlation between methylation and expression changes in response to exercise training. The majority of these genes were related to muscle growth and differentiation, and a minor fraction involved in metabolic regulation. Among the candidates were genes that regulate the expression of myogenic regulatory factors (Plexin A2) as well as genes that participate in muscle hypertrophy (Igfbp4) and motor neuron innervation (Dok7). Interestingly, a transcription factor binding site enrichment study discovered significantly enriched occurrence of CpG methylation in the binding sites of the myogenic regulatory factors MyoD and myogenin. These findings suggest that DNA methylation is involved in the regulation of muscle adaptation to regular exercise training.

  18. Assignment and expression patterns of porcine muscle-specific isoform of phosphoglycerate mutase gene

    Institute of Scientific and Technical Information of China (English)

    Haifang Qiu; Shuhong Zhao; Xuewen Xu; Martine Yerle; Bang Liu

    2008-01-01

    It has been reported that the muscle-specific isoform (type M, PGAM2) of phosphoglycerate mutase (PGAM) is a housekeeping en-zyme; it catalyzes the conversion of 3-phospboglycerate into 2-phosphoglycerate in the glyeolysis process to release energy. It is encoded by the Pgam2 gene. In this study, the eDNA of the porcine Pgam2 was cloned. This gene contains an open reading frame of 765 bp en-coding a protein of 253 residues, and the predicted protein sequences share high similarity with other mammalians, 96% identity with humans, and 94% identity with mouse and rats. Pgam2 was mapped to SSC18q13-q21 by the RH panel. In this region, there are several QTLs, such as fat ratio, lean percentage, and diameter of muslce fiber, which affect meat production and quality. The reverse transcrip-tase-polymerase chain reaction revealed that the porcine Pgam2 gene was mainly expressed in the muscle tissue (skeletal muscle and cardiac muscle), and was expressed highly at skeletal muscle development stages (embryonic periods: 33, 65, and 90 days post-conception(dpe); postnatal pigs: 4 days and adult). This indicates that the Pgam2 gene plays an important role in muscle growth and development. In addition, it was demonstrated that PGAM2 locates both in cytoplasm and nuclei, and takes part in the glycometabolism process of cyto-plasm and nuclei.

  19. Block Co-Polymers for Nanolithography: Rapid Microwave Annealing for Pattern Formation on Substrates

    Directory of Open Access Journals (Sweden)

    Dipu Borah

    2015-03-01

    Full Text Available The integration of block copolymer (BCP self-assembled nanopattern formation as an alternative lithographic tool for nanoelectronic device fabrication faces a number of challenges such as defect densities, feature size, pattern transfer, etc. Key barriers are the nanopattern process times and pattern formation on current substrate stack layers such as hard masks (e.g., silicon nitride, Si3N4. We report a rapid microwave assisted solvothermal (in toluene environments self-assembly and directed self-assembly of a polystyrene-block-polydimethylsiloxane (PS-b-PDMS BCP thin films on planar and topographically patterned Si3N4 substrates. Hexagonally arranged, cylindrical structures were obtained and good pattern ordering was achieved. Factors affecting BCP self-assembly, notably anneal time and temperature, were studied and seen to have significant effects. Graphoepitaxy within the topographical structures provided long range, translational alignment of the patterns. The effect of surface topography feature size and spacing was investigated. The solvothermal microwave based technique used to provide periodic order in the BCP patterns showed significant promise and ordering was achieved in much shorter periods than more conventional thermal and solvent annealing methods. The implications of the work in terms of manufacturing technologies are discussed.

  20. The Developmental Genetics of Vertebrate Color Pattern Formation: Lessons from Zebrafish.

    Science.gov (United States)

    Irion, Uwe; Singh, Ajeet Pratap; Nüsslein-Volhard, Christiane

    2016-01-01

    Color patterns are prominent features of many animals; they are highly variable and evolve rapidly leading to large diversities even within a single genus. As targets for natural as well as sexual selection, they are of high evolutionary significance. The zebrafish (Danio rerio) has become an important model organism for developmental biology and biomedical research in general, and it is the model organism to study color pattern formation in vertebrates. The fish display a conspicuous pattern of alternating blue and golden stripes on the body and on the anal and tail fins. This pattern is produced by three different types of pigment cells (chromatophores) arranged in precise layers in the hypodermis of the fish. In this essay, we will summarize the recent advances in understanding the developmental and genetic basis for stripe formation in the zebrafish. We will describe the cellular events leading to the formation of stripes during metamorphosis based on long-term lineage imaging. Mutant analysis has revealed that a number of signaling pathways are involved in the establishment and maintenance of the individual pigment cells. However, the striped pattern itself is generated by self-organizing mechanisms requiring interactions between all three pigment cell types. The involvement of integral membrane proteins, including connexins and potassium channels, suggests that direct physical contacts between chromatophores are involved, and that the directed transport of small molecules or bioelectrical coupling is important for these interactions. This mode of patterning by transmitting spatial information between adjacent tissues within three superimposed cell layers is unprecedented in other developmental systems. We propose that variations in the patterns among Danio species are caused by allelic differences in the genes responsible for these interactions.

  1. The effect of age and knee osteoarthritis on muscle activation patterns and knee joint biomechanics during dual belt treadmill gait.

    Science.gov (United States)

    Rutherford, Derek; Baker, Matthew; Wong, Ivan; Stanish, William

    2017-06-01

    To compare a group of individuals with moderate medial compartment knee osteoarthritis (OA) to both an age-matched asymptomatic group of older adults and younger adults to determine whether differences in knee joint muscle activation patterns and joint biomechanics exist during gait between these three groups. 20 young adults, 20 older adults, and 40 individuals with moderate knee OA were recruited. Using standardized procedures, surface electromyograms were recorded from the vastus lateralis and medialis, rectus femoris and the medial and lateral hamstrings. All individuals walked on a dual belt instrumented treadmill while segment motions and ground reaction forces were recorded. Sagittal plane motion and net external sagittal and frontal plane moments were calculated. Discrete measures and principal component analyses extracted amplitude and temporal waveform features. Analysis of Variance models using Bonferroni corrections determined between and within group differences in these gait features (α=0.05). Individuals with knee OA have distinct biomechanics and muscle activation patterns when compared to age-matched asymptomatic adults and younger adults whereas differences between the young and older adults were few and included only measures of muscle activation amplitude. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. X-ray diffraction from flight muscle with a headless myosin mutation: implications for interpreting reflection patterns

    Science.gov (United States)

    Iwamoto, Hiroyuki; Trombitás, Károly; Yagi, Naoto; Suggs, Jennifer A.; Bernstein, Sanford I.

    2014-01-01

    Fruit fly (Drosophila melanogaster) is one of the most useful animal models to study the causes and effects of hereditary diseases because of its rich genetic resources. It is especially suitable for studying myopathies caused by myosin mutations, because specific mutations can be induced to the flight muscle-specific myosin isoform, while leaving other isoforms intact. Here we describe an X-ray-diffraction-based method to evaluate the structural effects of mutations in contractile proteins in Drosophila indirect flight muscle. Specifically, we describe the effect of the headless myosin mutation, Mhc10-Y97, in which the motor domain of the myosin head is deleted, on the X-ray diffraction pattern. The loss of general integrity of the filament lattice is evident from the pattern. A striking observation, however, is the prominent meridional reflection at d = 14.5 nm, a hallmark for the regularity of the myosin-containing thick filament. This reflection has long been considered to arise mainly from the myosin head, but taking the 6th actin layer line reflection as an internal control, the 14.5-nm reflection is even stronger than that of wild-type muscle. We confirmed these results via electron microscopy, wherein image analysis revealed structures with a similar periodicity. These observations have major implications on the interpretation of myosin-based reflections. PMID:25400584

  3. Colonic smooth muscle cells and colonic motility patterns as a target for irritable bowel syndrome therapy: mechanisms of action of otilonium bromide

    OpenAIRE

    Rychter, Jakub; Espín, Francisco; Gallego, Diana; Vergara, Patri; Jiménez, Marcel; Clavé, Pere

    2014-01-01

    Otilonium bromide (OB) is a spasmolytic compound of the family of quaternary ammonium derivatives and has been successfully used in the treatment of patients with irritable bowel syndrome (IBS) due to its specific pharmacodynamic effects on motility patterns in the human colon and the contractility of colonic smooth muscle cells. This article examines how. OB inhibits the main patterns of human sigmoid motility in vitro, which are spontaneous rhythmic phasic contractions, smooth muscle tone, ...

  4. Growth hormone mitigates loss of periosteal bone formation and muscle mass in disuse osteopenic rats

    DEFF Research Database (Denmark)

    Grubbe, M-C; Thomsen, Jesper Skovhus; Nyengaard, J R

    2014-01-01

    Growth hormone (GH) is a potent anabolic agent capable of increasing both bone and muscle mass. The aim was to investigate whether GH could counteract disuse-induced loss of bone and muscle mass in a rat model. Paralysis was induced by injecting 4 IU Botox (BTX) into the muscles of the right hind......BMD, -13%, Pmuscle mass (-69%, Pmuscle cell cross sectional area (CSA) (-73%, P... of periosteal BFR/BS (2-fold increase vs. BTX, Pmuscle mass (+29% vs. BTX, Pmuscle CSA (+11%, P=0.064). In conclusion, GH mitigates disuse...

  5. Genome-wide patterns of promoter sharing and co-expression in bovine skeletal muscle

    Directory of Open Access Journals (Sweden)

    Dalrymple Brian P

    2011-01-01

    Full Text Available Abstract Background Gene regulation by transcription factors (TF is species, tissue and time specific. To better understand how the genetic code controls gene expression in bovine muscle we associated gene expression data from developing Longissimus thoracis et lumborum skeletal muscle with bovine promoter sequence information. Results We created a highly conserved genome-wide promoter landscape comprising 87,408 interactions relating 333 TFs with their 9,242 predicted target genes (TGs. We discovered that the complete set of predicted TGs share an average of 2.75 predicted TF binding sites (TFBSs and that the average co-expression between a TF and its predicted TGs is higher than the average co-expression between the same TF and all genes. Conversely, pairs of TFs sharing predicted TGs showed a co-expression correlation higher that pairs of TFs not sharing TGs. Finally, we exploited the co-occurrence of predicted TFBS in the context of muscle-derived functionally-coherent modules including cell cycle, mitochondria, immune system, fat metabolism, muscle/glycolysis, and ribosome. Our findings enabled us to reverse engineer a regulatory network of core processes, and correctly identified the involvement of E2F1, GATA2 and NFKB1 in the regulation of cell cycle, fat, and muscle/glycolysis, respectively. Conclusion The pivotal implication of our research is two-fold: (1 there exists a robust genome-wide expression signal between TFs and their predicted TGs in cattle muscle consistent with the extent of promoter sharing; and (2 this signal can be exploited to recover the cellular mechanisms underpinning transcription regulation of muscle structure and development in bovine. Our study represents the first genome-wide report linking tissue specific co-expression to co-regulation in a non-model vertebrate.

  6. Formation mechanism of ordered stress-relief patterns in a free sustained Cu film system

    Institute of Scientific and Technical Information of China (English)

    Chen Miao-Gen; Xie Jian-Ping; Jin Jin-Sheng; Xia A-Gen; Ye Gao-Xiang

    2008-01-01

    A nearly free sustained copper (Cu) film system has been successfully fabricated by thermal evaporation deposition of Cu atoms on silicone oil surfaces,and a characteristic ordered pattern has been systematically studied.The ordered pattern,namely,band,is composed of a large number of parallel key-formed domains with different width w but nearly uniform length L;its characteristic values of ω and L are very susceptible to the growth period,deposition rate and nominal film thickness.The formation mechanism of the ordered patterns is well explained in terms of the relaxation of the internal stress in the films,which is related to the nearly zero adhesion of the solid-liquid interface.By using a two-time deposition method,it is confirmed that the ordered patterns really form in the vacuum chamber.

  7. Simultaneous formation of fine and large-area electrode patterns using screen-offset printing and its application to the patterning on adhesive materials

    Science.gov (United States)

    Nomura, Ken-ichi; Ushijima, Hirobumi; Nagase, Kazuro; Ikedo, Hiroaki; Mitsui, Ryosuke; Sato, Junya; Takahashi, Seiya; Nakajima, Shin-ichiro; Arai, Masahiro; Kurata, Yuji; Iwata, Shiro

    2016-03-01

    Additive-type printing techniques such as gravure-offset printing and screen printing are effective for low-cost and ecofriendly electrode pattern formation. Gravure-offset printing is effective for fine pattern formation with widths on the order of 10-20 µm, whereas screen printing is effective for the formation of large-area patterns. However, it is difficult to simultaneously form fine and large-area patterns using these printing techniques. In this study, we demonstrate that fine (minimum width of 15 µm) and medium- as well as large-area patterns can be formed simultaneously using our developed screen-offset printing technique, which is a combination of screen printing on a silicone blanket and transfer printing from the blanket to a substrate. Furthermore, we demonstrate the application of our method to printing on adhesive materials, which allows electrode formation without applying heat to the film substrate.

  8. [New formation of elastic fiber material in aortic defects covered with muscle flaps].

    Science.gov (United States)

    Klima, G; Papp, C

    1985-01-01

    The examination of the coverage of vascular defects with intercostal muscles showed during an observation period of 7 weeks the development of cartilage tissue with thick elastic fiber nettings running between the chondroma.

  9. Assessing altered motor unit recruitment patterns in paretic muscles of stroke survivors using surface electromyography

    Science.gov (United States)

    Hu, Xiaogang; Suresh, Aneesha K.; Rymer, William Z.; Suresh, Nina L.

    2015-12-01

    Objective. The advancement of surface electromyogram (sEMG) recording and signal processing techniques has allowed us to characterize the recruitment properties of a substantial population of motor units (MUs) non-invasively. Here we seek to determine whether MU recruitment properties are modified in paretic muscles of hemispheric stroke survivors. Approach. Using an advanced EMG sensor array, we recorded sEMG during isometric contractions of the first dorsal interosseous muscle over a range of contraction levels, from 20% to 60% of maximum, in both paretic and contralateral muscles of stroke survivors. Using MU decomposition techniques, MU action potential amplitudes and recruitment thresholds were derived for simultaneously activated MUs in each isometric contraction. Main results. Our results show a significant disruption of recruitment organization in paretic muscles, in that the size principle describing recruitment rank order was materially distorted. MUs were recruited over a very narrow force range with increasing force output, generating a strong clustering effect, when referenced to recruitment force magnitude. Such disturbances in MU properties also correlated well with the impairment of voluntary force generation. Significance. Our findings provide direct evidence regarding MU recruitment modifications in paretic muscles of stroke survivors, and suggest that these modifications may contribute to weakness for voluntary contractions.

  10. Formation and characteristics of patterns in atmospheric-pressure radio-frequency dielectric barrier discharge plasma

    Science.gov (United States)

    Yang, Lizhen; Liu, Zhongwei; Mao, Zhiguo; Li, Sen; Chen, Qiang

    2017-01-01

    The patterns in radio-frequency dielectric barrier discharge (RF DBD) are studied at atmospheric pressure of argon (Ar) or helium (He) mixed with nitrogen (N2) gas. When a small amount of N2 is mixed with He or Ar gas, discharge patterns are formed. In a N2/He gas mixture, besides the filament discharge that forms patterns, a glow background discharge is also observed, whereas only the filament discharge forms patterns in a N2/Ar gas mixture. The resolution of the hexagonal pattern as a function of applied power and gas flow rate is then explored. On the basis of spatial-temporal images taken using an intensified charge-coupled device (ICCD), we find that there is no interleaving of two transient hexagon sublattices in N2/Ar or N2/He plasma in RF DBD patterns, which are totally different from those in which surface charges dominated in the mid-frequency DBD plasma. This supports our hypothesis that the bulk charges dominate the pattern formation in RF DBD.

  11. Formation and all-optical control of optical patterns in semiconductor microcavities

    Science.gov (United States)

    Binder, R.; Tsang, C. Y.; Tse, Y. C.; Luk, M. H.; Kwong, N. H.; Chan, Chris K. P.; Leung, P. T.; Lewandowski, P.; Schumacher, Stefan; Lafont, O.; Baudin, E.; Tignon, J.

    2016-05-01

    Semiconductor microcavities offer a unique way to combine transient all-optical manipulation of GaAs quantum wells with the benefits of structural advantages of microcavities. In these systems, exciton-polaritons have dispersion relations with very small effective masses. This has enabled prominent effects, for example polaritonic Bose condensation, but it can also be exploited for the design of all-optical communication devices. The latter involves non-equilibrium phase transitions in the spatial arrangement of exciton-polaritons. We consider the case of optical pumping with normal incidence, yielding a spatially homogeneous distribution of exciton-polaritons in optical cavities containing the quantum wells. Exciton-exciton interactions can trigger instabilities if certain threshold behavior requirements are met. Such instabilities can lead, for example, to the spontaneous formation of hexagonal polariton lattices (corresponding to six-spot patterns in the far field), or to rolls (corresponding to two-spot far field patterns). The competition among these patterns can be controlled to a certain degree by applying control beams. In this paper, we summarize the theory of pattern formation and election in microcavities and illustrate the switching between patterns via simulation results.

  12. A new computational approach to simulate pattern formation in Paenibacillus dendritiformis bacterial colonies

    Science.gov (United States)

    Tucker, Laura Jane

    Under the harsh conditions of limited nutrient and hard growth surface, Paenibacillus dendritiformis in agar plates form two classes of patterns (morphotypes). The first class, called the dendritic morphotype, has radially directed branches. The second class, called the chiral morphotype, exhibits uniform handedness. The dendritic morphotype has been modeled successfully using a continuum model on a regular lattice; however, a suitable computational approach was not known to solve a continuum chiral model. This work details a new computational approach to solving the chiral continuum model of pattern formation in P. dendritiformis. The approach utilizes a random computational lattice and new methods for calculating certain derivative terms found in the model.

  13. Mechanisms of pattern formation in grazing-incidence ion bombardment of Pt(111)

    OpenAIRE

    Hansen, H; Redinger, A.; Messlinger, S.; Stoian, G.; Rosandi, Y.; Urbassek, H. M.; Linke, U.; Michely, T.

    2006-01-01

    Ripple patterns forming on Pt(111) due to 5 keV Ar+ grazing-incidence ion bombardment were investigated by scanning tunneling microscopy in a broad temperature range from 100 to 720 K and for ion fluences up to 3x10(20) ions/m(2). A detailed morphological analysis together with molecular dynamics simulations of single ion impacts allow us to develop atomic scale models for the formation of these patterns. The large difference in step edge versus terrace damage is shown to be crucial for rippl...

  14. Rhythmic pattern formations in gels and Matalon–Packter law: A fresh perspective

    Indian Academy of Sciences (India)

    Jacob George; Issac Paul; P A Varughese; George Varghese

    2003-06-01

    The periodic precipitation pattern formation in gelatinous media is interpreted as a moving boundary problem. The time law, spacing law and width law are revisited on the basis of the new scenario. The explicit dependence of the geometric structure on the initial concentrations of the reactants is derived. Matalon–Packter law, which relates the spacing coefficient with the initial concentrations is reformulated removing many ambiguities and impractical parameters. Experimental results are discussed to establish the significance of moving boundary concept in the diffusion controlled pattern forming systems.

  15. Effect of resistance training on neuromuscular junctions of young and aged muscles featuring different recruitment patterns.

    Science.gov (United States)

    Deschenes, Michael R; Sherman, E Grace; Roby, Mackenzie A; Glass, Emily K; Harris, M Brennan

    2015-03-01

    To examine the effects of aging on neuromuscular adaptations to resistance training (i.e., weight lifting), young (9 months of age) and aged (20 months of age) male rats either participated in a 7-week ladder climbing protocol with additional weight attached to their tails or served as controls (n = 10/group). At the conclusion, rats were euthanized and hindlimb muscles were quickly removed and frozen for later analysis. Longitudinal sections of the soleus and plantaris muscles were collected, and pre- and postsynaptic features of neuromuscular junctions (NMJs) were visualized with immunofluorescence staining procedures. Cross-sections of the same muscles were histochemically stained to determine myofiber profiles (fiber type and size). Statistical analysis was by two-way ANOVA (main effects of age and treatment) with significance set at P ≤ 0.05. Results revealed that training-induced remodeling of NMJs was evident only at the postsynaptic endplate region of soleus fast-twitch myofibers. In contrast, aging was associated with pre- and postsynaptic remodeling in fast- and slow-twitch myofibers of the plantaris. Although both the soleus and the plantaris muscles failed to display either training or aging-related alterations in myofiber size, aged plantaris muscles exhibited an increased expression of type I (slow-twitch) myofibers in conjunction with a reduced percentage of type II (fast-twitch) myofibers, suggesting early stages of sarcopenia. These data demonstrate the high degree of specificity of synaptic modifications made in response to exercise and aging and that the sparsely recruited plantaris is more vulnerable to the effects of aging than the more frequently recruited soleus muscle.

  16. Buckling patterns of gold thin films on silicon substrates: Formation of superimposed blisters

    Science.gov (United States)

    Colin, J.; Coupeau, C.; Durinck, J.; Grilhé, J.

    2009-06-01

    Buckling phenomena leading to the formation of superimposed blisters have been experimentally observed with the help of a confocal interferometric microscope onto the surface of gold thin films deposited on silicon substrates. Assuming that residual folding effects resulting from plastic deformation mechanisms take place in the film during its morphological evolution, different probable scenarios for the formation of the observed buckling patterns are elaborated in the framework of the Föppl-von Karman's theory of thin plates. Multi-step buckling with growing interface delamination is considered for the first scenario while a single or multi-step buckling at a given delamination width is assumed for the other ones.

  17. Pattern formation in spatially extended nonlinear systems: Toward a foundation for meaning in symbolic forms

    Science.gov (United States)

    DeMaris, David

    1998-07-01

    This paper brings together observations from a variety of fields to point toward what the author believes to be the most promising computational approach to the modeling of brain-like symbol formation, unifying perceptual and linguistic domains under a common computational physics. It brings Cassirer's Gestalt era evolutionary theory of language and symbolic thought to the attention of the situated cognition community, and describes how recent observations in experimental brain dynamics and computational approaches can be brought to bear on the problem. Research by the author and others in oscillatory network models of ambiguous perception with an attentional component is emphasised as a starting point for exploring increasingly complex pattern formation processes leading to simple forms of linguistic performance. These forms occupy a space between iconic representations and grammar. The dynamic pattern network framework suggests that to separate perception, representation or models and action in a realistic biophysics of situated organisms may be problematic.

  18. Turing Bifurcation and Pattern Formation of Stochastic Reaction-Diffusion System

    Directory of Open Access Journals (Sweden)

    Qianiqian Zheng

    2017-01-01

    Full Text Available Noise is ubiquitous in a system and can induce some spontaneous pattern formations on a spatially homogeneous domain. In comparison to the Reaction-Diffusion System (RDS, Stochastic Reaction-Diffusion System (SRDS is more complex and it is very difficult to deal with the noise function. In this paper, we have presented a method to solve it and obtained the conditions of how the Turing bifurcation and Hopf bifurcation arise through linear stability analysis of local equilibrium. In addition, we have developed the amplitude equation with a pair of wave vector by using Taylor series expansion, multiscaling, and further expansion in powers of small parameter. Our analysis facilitates finding regions of bifurcations and understanding the pattern formation mechanism of SRDS. Finally, the simulation shows that the analytical results agree with numerical simulation.

  19. Comparison of muscle activity patterns of transfemoral amputees and control subjects during walking

    NARCIS (Netherlands)

    Wentink, Eva C.; Prinsen, Eric C.; Rietman, Johan S.; Veltink, Peter H.

    2013-01-01

    Background Only few studies have looked at electromyography (EMG) during prosthetic gait. Differences in EMG between normal and prosthetic gait for stance and swing phase were never separately analyzed. These differences can give valuable information if and how muscle activity changes in prosthetic

  20. Agonist and Antagonist Muscle EMG Activity Pattern Changes with Skill Acquisition.

    Science.gov (United States)

    Engelhorn, Richard

    1983-01-01

    Using electromyography (EMG), researchers studied changes in the control of biceps and triceps brachii muscles that occurred as women college students learned two elbow flexion tasks. Data on EMG activity, angular kinematics, training, and angular displacement were analyzed. (Author/PP)

  1. Formation mechanism of dot-line square superlattice pattern in dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Weibo; Dong, Lifang, E-mail: donglfhbu@163.com, E-mail: pyy1616@163.com; Wang, Yongjie; Zhang, Xinpu [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); College of Quality and Technical Supervision, Hebei University, Baoding 071002 (China); Pan, Yuyang, E-mail: donglfhbu@163.com, E-mail: pyy1616@163.com [College of Quality and Technical Supervision, Hebei University, Baoding 071002 (China)

    2014-11-15

    We investigate the formation mechanism of the dot-line square superlattice pattern (DLSSP) in dielectric barrier discharge. The spatio-temporal structure studied by using the intensified-charge coupled device camera shows that the DLSSP is an interleaving of three different subpatterns in one half voltage cycle. The dot square lattice discharges first and, then, the two kinds of line square lattices, which form square grid structures discharge twice. When the gas pressure is varied, DLSSP can transform from square superlattice pattern (SSP). The spectral line profile method is used to compare the electron densities, which represent the amounts of surface charges qualitatively. It is found that the amount of surface charges accumulated by the first discharge of DLSSP is less than that of SSP, leading to a bigger discharge area of the following discharge (lines of DLSSP instead of halos of SSP). The spatial distribution of the electric field of the surface charges is simulated to explain the formation of DLSSP. This paper may provide a deeper understanding for the formation mechanism of complex superlattice patterns in DBD.

  2. Modeling and interpreting speckle pattern formation in swept-source optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Demidov, Valentin; Vitkin, I. Alex; Doronin, Alexander; Meglinski, Igor

    2017-03-01

    We report on the development of a unified Monte-Carlo based computational model for exploring speckle pattern formation in swept-source optical coherence tomography (OCT). OCT is a well-established optical imaging modality capable of acquiring cross-sectional images of turbid media, including biological tissues, utilizing back scattered low coherence light. The obtained OCT images include characteristic features known as speckles. Currently, there is a growing interest to the OCT speckle patterns due to their potential application for quantitative analysis of medium's optical properties. Here we consider the mechanisms of OCT speckle patterns formation for swept-source OCT approaches and introduce further developments of a Monte-Carlo based model for simulation of OCT signals and images. The model takes into account polarization and coherent properties of light, mutual interference of back-scattering waves, and their interference with the reference waves. We present a corresponding detailed description of the algorithm for modeling these light-medium interactions. The developed model is employed for generation of swept-source OCT images, analysis of OCT speckle formation and interpretation of the experimental results. The obtained simulation results are compared with selected analytical solutions and experimental studies utilizing various sizes / concentrations of scattering microspheres.

  3. Steady states and linear stability analysis of precipitation pattern formation at geothermal hot springs

    Science.gov (United States)

    Chan, Pak Yuen; Goldenfeld, Nigel

    2007-10-01

    A dynamical theory of geophysical precipitation pattern formation is presented and applied to irreversible calcium carbonate (travertine) deposition. Specific systems studied here are the terraces and domes observed at geothermal hot springs, such as those at Yellowstone National Park, and speleothems, particularly stalactites and stalagmites. The theory couples the precipitation front dynamics with shallow water flow, including corrections for turbulent drag and curvature effects. In the absence of capillarity and with a laminar flow profile, the theory predicts a one-parameter family of steady state solutions to the moving boundary problem describing the precipitation front. These shapes match the measured shapes near the vent at the top of observed travertine domes well. Closer to the base of the dome, the solutions deviate from observations and circular symmetry is broken by a fluting pattern, which we show is associated with capillary forces causing thin film break-up. We relate our model to that recently proposed for stalactite growth, and calculate the linear stability spectrum of both travertine domes and stalactites. Lastly, we apply the theory to the problem of precipitation pattern formation arising from turbulent flow down an inclined plane and identify a linear instability that underlies scale-invariant travertine terrace formation at geothermal hot springs.

  4. Self-Assembly, Pattern Formation and Growth Phenomena in Nano-Systems

    CERN Document Server

    Nepomnyashchy, Alexander A

    2006-01-01

    Nano-science and nano-technology are rapidly developing scientific and technological areas that deal with physical, chemical and biological processes that occur on nano-meter scale – one millionth of a millimeter. Self-organization and pattern formation play crucial role on nano-scales and promise new, effective routes to control various nano-scales processes. This book contains lecture notes written by the lecturers of the NATO Advanced Study Institute "Self-Assembly, Pattern Formation and Growth Phenomena in Nano-Systems" that took place in St Etienne de Tinee, France, in the fall 2004. They give examples of self-organization phenomena on micro- and nano-scale as well as examples of the interplay between phenomena on nano- and macro-scales leading to complex behavior in various physical, chemical and biological systems. They discuss such fascinating nano-scale self-organization phenomena as self-assembly of quantum dots in thin solid films, pattern formation in liquid crystals caused by light, self-organi...

  5. Antibiotic Resistance Pattern and Biofilm Formation Ability of Clinically Isolates of Salmonella enterica Serotype typhimurium

    Directory of Open Access Journals (Sweden)

    Hadi Ghasemmahdi

    2015-05-01

    Full Text Available Background: The emergence of antimicrobial-resistant bacteria with biofilm formation ability may be a major threat to public health and food safety and sanitation. Objectives: The aim of this study was to determine antibiotic resistance patterns and biofilm production characteristics of Salmonella typhimurium isolated from different species of birds. Materials and Methods: The antibiotic resistance patterns of 38 pre-identified isolates were screened by standard Kirby-Bauer disc-diffusion method performed on Mueller–Hinton agar to a panel of 17 antibiotics. The extent of biofilm formation was measured by Microtiter plate (MTP-based systems. Results: The highest antimicrobial resistance was detected against nalidixic acid (97%, followed by doxycycline (86%, colistin (84%, streptomycin (84% and tetracycline (84%. All isolates were sensitive to amikacin (100% and 97% and 95% of the isolates were sensitive to ceftazidime and ceftriaxone, respectively. Twenty one different antibiotic resistance patterns were observed among S. typhimurium isolates. According to the results of the microtitre plate biofilm assay, there was a wide variation in biofilm forming ability among S. typhimurium isolates. Most of the isolates (60.52% were not capable of producing biofilm, while 26.31%, 7.89%, and 5.26% isolates were weak, strong and moderate biofilm producers, respectively. Conclusions: It was concluded that nearly all S. typhimurium isolates revealed a high multiple antibiotic resistant with low biofilm forming capabilities which proposed low association between biofilm formation and antibiotic resistance of a major food important pathogen.

  6. Mosaic-pattern vegetation formation and dynamics driven by the water-wind crisscross erosion

    Science.gov (United States)

    Wu, Gao-Lin; Wang, Dong; Liu, Yu; Hao, Hong-Min; Fang, Nu-Fang; Shi, Zhi-Hua

    2016-07-01

    Theoretical explanations for vegetation pattern dynamic emphasized on banded pattern-forming systems on the dynamics of the spot pattern. In this context, we explore the patch pattern forming and development in the desertification land. We hypothesized that spatial heterogeneity of microtopography and soil properties with different patch sizes would determine vegetation pattern dynamics theory. The spatial heterogeneity of microtopography and soil properties with different patch sizes were studied. Differences between the inside and outside of the canopy of soil carbon content and soil total nitrogen content were significantly increasing with patches sizes. Sampling location across vegetation patch was the main factor controlling soil properties. Soil nutrient content and saturated hydraulic conductivity were the largest, while bulk density and the coarse sand content were the lowest at the sampling location of half-way between taproot and downslope edge of the canopy. The height of the mound relative to the adjacent soil interspace between shrubs increased as patches diameter increased at the upslope of the taproot. Hydrological and aeolian processes resulted in spatial distributions of soil moisture, nutrition properties, which lead to patch migrated to downslope rather than upslope. A conceptual model was integrated hydrological and nutrient facilitation and competition effects among the plant-soil in mosaic-pattern patch formation and succession process.

  7. ARGONAUTE1 acts in Arabidopsis root radial pattern formation independently of the SHR/SCR pathway.

    Science.gov (United States)

    Miyashima, Shunsuke; Hashimoto, Takashi; Nakajima, Keiji

    2009-03-01

    The formation of radially symmetric tissue patterns is one of the most basic processes in the development of vascular plants. In Arabidopsis thaliana, plant-specific GRAS-type transcription factors, SHORT-ROOT (SHR) and SCARECROW (SCR), are required for asymmetric cell divisions that separate two ground tissue cell layers, the endodermis and cortex, as well as for endodermal cell fate specification. While loss of SHR or SCR results in a single-layered ground tissue, radially symmetric cellular patterns are still maintained, suggesting that unknown regulatory mechanisms act independently of the SHR/SCR-dependent pathway. In this study, we identified a novel root radial pattern mutant and found that it is a new argonaute1 (ago1) allele. Multiple ago1 mutant alleles contained supernumerary ground tissue cell layers lacking a concentric organization, while expression patterns of SHR and SCR were not affected, revealing a previously unreported role for AGO1 in root ground tissue patterning. Analyses of ago1 scr double mutants demonstrated that the simultaneous loss of the two pathways caused a dramatic reduction in cellular organization and ground tissue identity as compared with the single mutants. Based on these results, we propose that highly symmetric root ground tissue patterns are maintained by the actions of two independent pathways, one using post-transcriptional regulation mediated by AGO1 and the other using the SHR/SCR transcriptional regulator.

  8. Localization and Pattern Formation in Quantum Physics. II. Waveletons in Quantum Ensembles

    CERN Document Server

    Fedorova, A N; Fedorova, Antonina N.; Zeitlin, Michael G.

    2005-01-01

    In this second part we present a set of methods, analytical and numerical, which can describe behaviour in (non) equilibrium ensembles, both classical and quantum, especially in the complex systems, where the standard approaches cannot be applied. The key points demonstrating advantages of this approach are: (i) effects of localization of possible quantum states; (ii) effects of non-perturbative multiscales which cannot be calculated by means of perturbation approaches; (iii) effects of formation of complex/collective quantum patterns from localized modes and classification and possible control of the full zoo of quantum states, including (meta) stable localized patterns (waveletons). We demonstrate the appearance of nontrivial localized (meta) stable states/patterns in a number of collective models covered by the (quantum)/(master) hierarchy of Wigner-von Neumann-Moyal-Lindblad equations, which are the result of ``wignerization'' procedure (Weyl-Wigner-Moyal quantization) of classical BBGKY kinetic hierarchy...

  9. Turing pattern formation in the chlorine dioxide-iodine- malonic acid reaction-diffusion system

    Science.gov (United States)

    Setayeshgar, Sima

    The formation of localized structures in the chlorine dioxide-idodine-malonic acid (CDIMA) reaction-diffusion system is investigated numerically using a realistic model of this system. We analyze the one-dimensional patterns formed along the gradients imposed by boundary feeds, and study their linear stability to symmetry- breaking perturbations (the Turing instability) in the plane transverse to these gradients. We establish that an often-invoked simple local linear analysis which neglects longitudinal diffusion is inappropriate for predicting the linear stability of these patterns. Using a fully nonuniform analysis, we investigate the structure of the patterns formed along the gradients and their stability to transverse Turing pattern formation as a function of the values of two control parameters: the malonic acid feed concentration and the size of the reactor in the dimension along the gradients. The results from this investigation are compared with existing experimental results. We also verify that the two-variable reduction of the chemical model employed in the linear stability analysis is justified. Finally, we present numerical solution of the CDIMA system in two dimensions which is in qualitative agreement with experiments. This result also confirms our linear stability analysis, while demonstrating the feasibility of numerical exploration of realistic chemical models.

  10. An Integrative Approach for Modeling and Simulation of Heterocyst Pattern Formation in Cyanobacteria Filaments

    Science.gov (United States)

    Torres-Sánchez, Alejandro; Gómez-Gardeñes, Jesús; Falo, Fernando

    2015-01-01

    Heterocyst differentiation in cyanobacteria filaments is one of the simplest examples of cellular differentiation and pattern formation in multicellular organisms. Despite of the many experimental studies addressing the evolution and sustainment of heterocyst patterns and the knowledge of the genetic circuit underlying the behavior of single cyanobacterium under nitrogen deprivation, there is still a theoretical gap connecting these two macroscopic and microscopic processes. As an attempt to shed light on this issue, here we explore heterocyst differentiation under the paradigm of systems biology. This framework allows us to formulate the essential dynamical ingredients of the genetic circuit of a single cyanobacterium into a set of differential equations describing the time evolution of the concentrations of the relevant molecular products. As a result, we are able to study the behavior of a single cyanobacterium under different external conditions, emulating nitrogen deprivation, and simulate the dynamics of cyanobacteria filaments by coupling their respective genetic circuits via molecular diffusion. These two ingredients allow us to understand the principles by which heterocyst patterns can be generated and sustained. In particular, our results point out that, by including both diffusion and noisy external conditions in the computational model, it is possible to reproduce the main features of the formation and sustainment of heterocyst patterns in cyanobacteria filaments as observed experimentally. Finally, we discuss the validity and possible improvements of the model. PMID:25816286

  11. Expression patterns of two potassium channel genes in skeletal muscle cells of patients with familial hypokalemic periodic paralysis.

    Science.gov (United States)

    Kim, June-Bum; Lee, Gyung-Min; Kim, Sung-Jo; Yoon, Dong-Ho; Lee, Young-Hyuk

    2011-01-01

    Familial hypokalemic periodic paralysis is an autosomal-dominant disorder characterized by episodic attacks of muscle weakness with hypokalemia. The combination of sarcolemmal depolarization and hypokalemia has been attributed to abnormalities of the potassium conductance governing the membrane potential; however, the molecular mechanism that causes hypokalemia has not yet been determined. To test the hypothesis that the expression patterns of delayed rectifier potassium channel genes in the skeletal muscle cells of patients with familial hypokalemic periodic paralysis differ from those in normal cells. We examined both mRNA and protein levels of two major delayed rectifier potassium channel genes KCNQ3 and KCNQ5 in the skeletal muscle cells from three patients with familial hypokalemic periodic paralysis and three healthy controls. When normal cells were exposed to 50 mM potassium buffer, which was used to induce depolarization, the KCNQ3 protein level significantly increased in the membrane fraction but decreased in the cytosolic fraction, whereas the opposite was true in patient cells. Abnormal subcellular distribution of the KCNQ3 protein was observed in patient cells. Our results suggest that the altered expression of KCNQ3 in patient cells exposed to high extracellular potassium levels could possibly hinder normal function of the channel protein. These findings may provide an important clue to understanding the molecular mechanism of familial hypokalemic periodic paralysis.

  12. Expression patterns of two potassium channel genes in skeletal muscle cells of patients with familial hypokalemic periodic paralysis

    Directory of Open Access Journals (Sweden)

    June-Bum Kim

    2011-01-01

    Full Text Available Background: Familial hypokalemic periodic paralysis is an autosomal-dominant disorder characterized by episodic attacks of muscle weakness with hypokalemia. The combination of sarcolemmal depolarization and hypokalemia has been attributed to abnormalities of the potassium conductance governing the membrane potential; however, the molecular mechanism that causes hypokalemia has not yet been determined. Aim: To test the hypothesis that the expression patterns of delayed rectifier potassium channel genes in the skeletal muscle cells of patients with familial hypokalemic periodic paralysis differ from those in normal cells. Material and Methods: We examined both mRNA and protein levels of two major delayed rectifier potassium channel genes KCNQ3 and KCNQ5 in the skeletal muscle cells from three patients with familial hypokalemic periodic paralysis and three healthy controls. Results: When normal cells were exposed to 50 mM potassium buffer, which was used to induce depolarization, the KCNQ3 protein level significantly increased in the membrane fraction but decreased in the cytosolic fraction, whereas the opposite was true in patient cells. Conclusion: Abnormal subcellular distribution of the KCNQ3 protein was observed in patient cells. Our results suggest that the altered expression of KCNQ3 in patient cells exposed to high extracellular potassium levels could possibly hinder normal function of the channel protein. These findings may provide an important clue to understanding the molecular mechanism of familial hypokalemic periodic paralysis.

  13. Quantitative Effects of Repeated Muscle Vibrations on Gait Pattern in a 5-Year-Old Child with Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Filippo Camerota

    2011-01-01

    Full Text Available Objective. To investigate quantitatively and objectively the effects of repeated muscle vibration (rMV of triceps surae on the gait pattern in a 5-year-old patient with Cerebral Palsy with equinus foot deformity due to calf spasticity. Methods. The patient was assessed before and one month after the rMV treatment using Gait Analysis. Results. rMV had positive effects on the patient's gait pattern, as for spatio-temporal parameters (the stance duration and the step length increased their values after the treatment and kinematics. The pelvic tilt reduced its anteversion and the hip reduced the high flexion evidenced at baseline; the knee and the ankle gained a more physiological pattern bilaterally. The Gillette Gait Index showed a significant reduction of its value bilaterally, representing a global improvement of the child's gait pattern. Conclusions. The rMV technique seems to be an effective option for the gait pattern improvement in CP, which can be used also in very young patient. Significant improvements were displayed in terms of kinematics at all lower limb joints, not only at the joint directly involved by the treatment (i.e., ankle and knee joints but also at proximal joints (i.e., pelvis and hip joint.

  14. THE IMPACT OF ERGOMETER DESIGN ON HIP AND TRUNK MUSCLE ACTIVITY PATTERNS IN ELITE ROWERS: AN ELECTROMYOGRAPHIC ASSESSMENT

    Directory of Open Access Journals (Sweden)

    Sara Horne

    2005-03-01

    Full Text Available This study used surface electromyography (sEMG to examine whether there were differences in hip and trunk muscle activation during the rowing cycle on two of the most widely used air braked ergometers: the Concept 2C and the Rowperfect. sEMG methods were used to record the muscle activity patterns from the right: m. Erector spinae (ES, m. Rectus Abdominus (RA, m. Rectus Femoris (RF and m. Biceps Femoris (BF for their contributions as agonist-antagonist pairs underlying hip and trunk extension/flexion. The sEMG activity patterns of these muscles were examined in six young male elite rowers completing a 2 minute set at a moderate training intensity (23 stroke·min-1 and 1:47.500 m-1 split time, 300W. The rowers closely maintained the required target pace through visual inspection of the standard LCD display of each ergometer. The measurements of duration of each rowing cycle and onset of each stroke during the test were recorded simultaneously with the sEMG activity through the additional instrumentation of a foot-pressure switch and handle accelerometry. There were no significant differences between the two ergometer designs in group means for: work rate (i.e., rowing speed and stroke rate, metabolic load as measured by mean heart rate, rowing cycle duration, or timing of the stroke in the cycle. 2-D motion analysis of hip and knee motion for the rowing cycle from the video footage taken during the test also revealed no significant differences in the joint range of motion between the ergometers. Ensemble average sEMG activity profiles based on 30+ strokes were obtained for each participant and normalised per 10% intervals of the cycle duration as well as for peak mean sEMG amplitude for each muscle. A repeated measures ANOVA on the sEMG activity per 10% interval for the four muscles contributing to hip and trunk motion during the rowing cycle revealed no significant differences between the Concept 2C and Rowperfect (F = 0.070, df = 1,5, p = 0

  15. A Preliminary Study on the Pattern, the Physiological Bases and the Molecular Mechanism of the Adductor Muscle Scar Pigmentation in Pacific Oyster Crassostrea gigas

    Directory of Open Access Journals (Sweden)

    Wenchao Yu

    2017-09-01

    Full Text Available The melanin pigmentation of the adductor muscle scar and the outer surface of the shell are among attractive features and their pigmentation patterns and mechanism still remains unknown in the Pacific oyster Crassostrea gigas. To study these pigmentation patterns, the colors of the adductor muscle scar vs. the outer surface of the shell on the same side were compared. No relevance was found between the colors of the adductor muscle scars and the corresponding outer surface of the shells, suggesting that their pigmentation processes were independent. Interestingly, a relationship between the color of the adductor muscle scars and the dried soft-body weight of Pacific oysters was found, which could be explained by the high hydroxyl free radical scavenging capacity of the muscle attached to the black adductor muscle scar. After the transcriptomes of pigmented and unpigmented adductor muscles and mantles were studied by RNAseq and compared, it was found that the retinol metabolism pathway were likely to be involved in melanin deposition on the adductor muscle scar and the outer surface of the shell, and that the different members of the tyrosinase or Cytochrome P450 gene families could play a role in the independent pigmentation of different organs.

  16. A pilot study using magnetic resonance imaging to determine the pattern of muscle group recruitment by rowers with different levels of experience

    Energy Technology Data Exchange (ETDEWEB)

    Green, R.A.R. [Radiology Dept. Royal National Orthopaedic Hospital Trust, Stanmore (United Kingdom); Wilson, D.J. [Radiology Dept., Nuffield Orthopaedic Centre NHS Trust, Oxford (United Kingdom)

    2000-04-01

    Objective. To determine whether it was possible using magnetic resonance imaging (MRI) to define the pattern of muscle recruitment in a specific sport (rowing) and to see whether there were differences in this pattern between athletes of different experience.Design and method. It has been shown that during vigorous exercise the water content of muscle increases transiently. This can be observed using MRI, where the prolonged T2 relaxation time of muscle can be demonstrated. In this study we have exploited the increase in signal seen in exercised muscle on short TI inversion recovery (STIR) sequences, to show how rowers of different experience use different muscle groups.Results. We have shown that trained athletes recruit selected muscle groups to carry out a given task, which they carry out more efficiently than untrained or less experienced athletes.Conclusion. We have provided the basis of potential research to refine training methods, in order to develop specific muscle groups in athletes, in the hope of achieving a higher level of performance at an earlier stage in their training. We have also defined a technique that may be of clinical value in cases of muscle dysfunction. (orig.)

  17. Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports.

    Science.gov (United States)

    Escamilla, Rafael F; Andrews, James R

    2009-01-01

    Understanding when and how much shoulder muscles are active during upper extremity sports is helpful to physicians, therapists, trainers and coaches in providing appropriate treatment, training and rehabilitation protocols to these athletes. This review focuses on shoulder muscle activity (rotator cuff, deltoids, pectoralis major, latissimus dorsi, triceps and biceps brachii, and scapular muscles) during the baseball pitch, the American football throw, the windmill softball pitch, the volleyball serve and spike, the tennis serve and volley, baseball hitting, and the golf swing. Because shoulder electromyography (EMG) data are far more extensive for overhead throwing activities compared with non-throwing upper extremity sports, much of this review focuses on shoulder EMG during the overhead throwing motion. Throughout this review shoulder kinematic and kinetic data (when available) are integrated with shoulder EMG data to help better understand why certain muscles are active during different phases of an activity, what type of muscle action (eccentric or concentric) occurs, and to provide insight into the shoulder injury mechanism. Kinematic, kinetic and EMG data have been reported extensively during overhead throwing, such as baseball pitching and football passing. Because shoulder forces, torques and muscle activity are generally greatest during the arm cocking and arm deceleration phases of overhead throwing, it is believed that most shoulder injuries occur during these phases. During overhead throwing, high rotator cuff muscle activity is generated to help resist the high shoulder distractive forces approximately 80-120% bodyweight during the arm cocking and deceleration phases. During arm cocking, peak rotator cuff activity is 49-99% of a maximum voluntary isometric contraction (MVIC) in baseball pitching and 41-67% MVIC in football throwing. During arm deceleration, peak rotator cuff activity is 37-84% MVIC in baseball pitching and 86-95% MVIC in football

  18. Muscle Patterning in Mouse and Human Abdominal Wall Development and Omphalocele Specimens of Humans

    OpenAIRE

    Nichol, Peter F.; Corliss, Robert F.; Yamada, Shigehito; SHIOTA, KOHEI; Saijoh, Yukio

    2012-01-01

    Human omphalocele is a congenital defect of the abdominal wall in which the secondary abdominal wall structures (muscle and connective tissue) in an area centered around the umbilicus are replaced by a translucent membranous layer of tissue. Histological examination of omphalocele development and moreover the staging of normal human abdominal wall development has never been described. We hypothesized that omphalocele is the result of an arrest in the secondary abdominal wall development and p...

  19. Patterns of anterior and posterior muscle chain interactions during high performance long-hang elements in gymnastics.

    Science.gov (United States)

    von Laßberg, Christoph; Rapp, Walter; Krug, Jürgen

    2014-06-01

    In a prior study with high level gymnasts we could demonstrate that the neuromuscular activation pattern during the "whip-like" leg acceleration phases (LAP) in accelerating movement sequences on high bar, primarily runs in a consecutive succession from the bar (punctum fixum) to the legs (punctum mobile). The current study presents how the neuromuscular activation is represented during movement sequences that immediately follow the LAP by the antagonist muscle chain to generate an effective transfer of momentum for performing specific elements, based on the energy generated by the preceding LAP. Thirteen high level gymnasts were assessed by surface electromyography during high performance elements on high bar and parallel bars. The results show that the neuromuscular succession runs primarily from punctum mobile towards punctum fixum for generating the transfer of momentum. Additionally, further principles of neuromuscular interactions between the anterior and posterior muscle chain during such movement sequences are presented. The findings complement the understanding of neuromuscular activation patterns during rotational movements around fixed axes and will help to form the basis of more direct and better teaching methods regarding earlier optimization and facilitation of the motor learning process concerning fundamental movement requirements. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Leg general muscle moment and power patterns in able-bodied subjects during recumbent cycle ergometry with ankle immobilization.

    Science.gov (United States)

    Szecsi, J; Straube, A; Fornusek, C

    2014-11-01

    Rehabilitation of persons with pareses commonly uses recumbent pedalling and a rigid pedal boot that fixes the ankle joint from moving. This study was performed to provide general muscle moments (GMM) and joint power data from able-bodied subjects performing recumbent cycling at two workloads. Twenty-six able-bodied subjects pedalled a stationary recumbent tricycle at 60 rpm during passive cycling and at two workloads (low 15 W and high 40 W per leg) while leg kinematics and pedal forces were recorded. GMM and power were calculated using inverse dynamic equations. During the high workload, the hip and knee muscles produced extensor/flexor moments throughout the extensions/flexions phases of the joints. For low workload, a prolonged (crank angle 0-258°) hip extension moment and a shortened range (350-150°) of knee extension moment were observed compared to the corresponding extension phases of each joint. The knee and hip joints generated approximately equal power. At the high workload the hip and knee extensors generated increased power in the propulsion phase. For the first time, this study provides GMM and power patterns for able-bodied subjects performing recumbent cycling with an immobilized ankle. The patterns showed greater similarities to upright cycling with a free ankle, than previously supposed.

  1. MFAP4 Promotes Vascular Smooth Muscle Migration, Proliferation and Accelerates Neointima Formation

    DEFF Research Database (Denmark)

    Schlosser, Anders; Pilecki, Bartosz; Hemstra, Line E.

    2016-01-01

    OBJECTIVE: Arterial injury stimulates remodeling responses that, when excessive, lead to stenosis. These responses are influenced by integrin signaling in vascular smooth muscle cells (VSMCs). Microfibrillar-associated protein 4 (MFAP4) is an integrin ligand localized to extracellular matrix fibers...

  2. Acylation of lysophosphatidylcholine and glycerolphosphate and fatty acid pattern in phosphatidylcholine and -ethanolamine in microsomes of normal and dystrophic human muscle.

    Science.gov (United States)

    Kunze, D; Rüstow, B; Kuksis, A; Myher, J J

    1986-02-01

    Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were isolated from microsomes obtained from normal and dystrophic human muscle and the fatty acid (FA) pattern estimated by GLC. In PC a decrease of the fatty acids of 16:0 and 18:2 and an increase of 18:0 and 18:1 was observed. In PE the decrease measured 18:2 and the increase 18:0 and 18:1. The acylation of lysophosphatidylcholine (LPC) and glycerol-3-phosphate (G3P) was measured in a microsomal system containing exogenously added LPC or G3P and labelled palmitic and oleic acid CoA esters. The incorporation of both labelled fatty acids in LPC-forming PC is reduced in dystrophic microsomes. On the other hand the acylation of glycerolphosphate and the formation of phosphatidic acid (PA) is greater in dystrophic microsomes when compared with normal controls. Possible correlations between the shifted FA pattern and the acylation rate by dystrophic microsomes measured in vitro in the two systems are discussed.

  3. Temporal patterns and behavioral characteristics of aggregation formation and spawning in the Bermuda chub ( Kyphosus sectatrix)

    Science.gov (United States)

    Nemeth, Richard S.; Kadison, Elizabeth

    2013-12-01

    Reef fish spawning aggregations are important life history events that occur at specific times and locations and represent the primary mode of reproduction for many species. This paper provides detailed descriptions of aggregation formation and mass spawning of the Bermuda chub ( Kyphosus sectatrix). Spawning coloration and gamete release of K. sectatrix were observed and filmed at the Grammanik Bank, a deep spawning aggregation site used by many different species located on the southern edge of the Puerto Rican shelf 10 km south of St. Thomas, US Virgin Islands. Underwater visual surveys using technical Nitrox and closed circuit re-breathers were conducted from December 2002 to March 2013 and documented spatial and temporal patterns of movement and aggregation formation along 1.5 km of mesophotic reef. The largest aggregations of K. sectatrix (>200 fish) were observed on the Grammanik Bank January to March from 0 to 11 d after the full moon with peak abundance from 60 to 80 d after the winter solstice across all survey years. Aggregation formation of K. sectatrix coincided with the spawning season of Nassau ( Epinephelus striatus) and yellowfin ( Mycteroperca venenosa) groupers. These spatial and temporal patterns of aggregation formation and spawning suggest that K. sectatrix, an herbivore, may also be a transient aggregating species. On several occasions, chubs were observed both pair spawning and mass spawning. Color patterns and behaviors associated with aggregation and spawning are described and compared to spawning characteristics observed in other species, many of which are similar but others that appear unique to K. sectatrix. This represents the first report of a kyphosid species aggregating to spawn and illuminates a portion of the poorly understood life history of the Bermuda chub.

  4. Dynamics of fast pattern formation in porous silicon by laser interference

    Energy Technology Data Exchange (ETDEWEB)

    Peláez, Ramón J.; Kuhn, Timo; Afonso, Carmen N. [Laser Processing Group, Instituto de Óptica, CSIC, Serrano 121, 28006 Madrid (Spain); Vega, Fidel [Departament d' Òptica i Optometria, UPC, Violinista Vellsolà 37, 08222 Terrasa (Spain)

    2014-10-20

    Patterns are fabricated on 290 nm thick nanostructured porous silicon layers by phase-mask laser interference using single pulses of an excimer laser (193 nm, 20 ns pulse duration). The dynamics of pattern formation is studied by measuring in real time the intensity of the diffraction orders 0 and 1 at 633 nm. The results show that a transient pattern is formed upon melting at intensity maxima sites within a time <30 ns leading to a permanent pattern in a time <100 ns upon solidification at these sites. This fast process is compared to the longer one (>1 μs) upon melting induced by homogeneous beam exposure and related to the different scenario for releasing the heat from hot regions. The diffraction efficiency of the pattern is finally controlled by a combination of laser fluence and initial thickness of the nanostructured porous silicon layer and the present results open perspectives on heat release management upon laser exposure as well as have potential for alternative routes for switching applications.

  5. The expansion of neighborhood and pattern formation on spatial prisoner's dilemma

    Science.gov (United States)

    Qian, Xiaolan; Xu, Fangqian; Yang, Junzhong; Kurths, Jürgen

    2015-04-01

    The prisoner's dilemma (PD), in which players can either cooperate or defect, is considered a paradigm for studying the evolution of cooperation in spatially structured populations. There the compact cooperator cluster is identified as a characteristic pattern and the probability of forming such pattern in turn depends on the features of the networks. In this paper, we investigate the influence of expansion of neighborhood on pattern formation by taking a weak PD game with one free parameter T, the temptation to defect. Two different expansion methods of neighborhood are considered. One is based on a square lattice and expanses along four directions generating networks with degree increasing with K = 4 m . The other is based on a lattice with Moore neighborhood and expanses along eight directions, generating networks with degree of K = 8 m . Individuals are placed on the nodes of the networks, interact with their neighbors and learn from the better one. We find that cooperator can survive for a broad degree 4 ≤ K ≤ 70 by taking a loose type of cooperator clusters. The former simple corresponding relationship between macroscopic patterns and the microscopic PD interactions is broken. Under a condition that is unfavorable for cooperators such as large T and K, systems prefer to evolve to a loose type of cooperator clusters to support cooperation. However, compared to the well-known compact pattern, it is a suboptimal strategy because it cannot help cooperators dominating the population and always corresponding to a low cooperation level.

  6. Mesoscopic study of the effects of gel concentration and materials on the formation of precipitation patterns.

    Science.gov (United States)

    Chen, Li; Kang, Qinjun; He, Ya-Ling; Tao, Wen-Quan

    2012-08-14

    A mesoscopic model based on the lattice Boltzmann method (LBM) is proposed to simulate the formation of Liesegang precipitation patterns and investigate the effects of gel on the morphology of the precipitates. In this model, nucleation is introduced on the basis of Ostwald's supersaturation theory, and subsequent crystal growth on the precipitate surface is simulated using a crystal growth model by taking into account the heterogeneous reaction on the surface of the precipitate. This model can capture the porous structures of the precipitates and can take into account the effects of the gel concentration and material by adjusting the gel porosity and nucleation threshold. The density of the precipitate nodes in the model is limited. A wide range of precipitation patterns is predicted under different gel concentrations, including regular bands, treelike patterns, and for the first time with numerical models, transition patterns between regular bands and treelike patterns. Both the spacing law and the width law are carefully investigated with different gel concentrations and gel materials, and the obtained α in the width law (w(n) ≈ x(n)(α), where x(n) and w(n) are the position and the width of the nth band, respectively) is in the range of 0.58-0.67, sandwiched by previously predicted ranges.

  7. On island landscape pattern of forests in Helan Mountain and its cause of formation

    Institute of Scientific and Technical Information of China (English)

    DENG; Hongbing; WANG; Yingming; ZHANG; Qiaoxian

    2006-01-01

    Based on the spatial information techniques such as RS, GIS, and GPS, the forest landscape patterns in the Helan Mountain, western China, were studied. The Landsat 5 TM data were used to classify the forest landscapes through RS digital cartography, and then, the landscape characteristics and landscape pattern were analyzed quantificationally. Furthermore, through spatial data collection and spatial analysis of the main disturbances in this area, the cause of landscape formation was studied. The results showed that the total 1177 forest landscape patches could be classified into 21 landscape types, and the forest landscape in the Helan Mountain was island pattern, which was encircled by deserta as matrix. The values of landscape diversity index and landscape fragmentation index were 2.61 and 0.43, respectively. In this area, the landscape pattern was clearly formed and continuously changed in response to geological processes, climate, activities of organisms, forest fire, desertification, human activities and so on. This landscape pattern had an obviously negative effect on the stability and ecosystem services of forests. So, scientific landscape planning and protection should be adopted to improve the sustainability of forest management in this area.

  8. The use of electromyography interference pattern analysis to determine muscle force of the deep digital flexor muscle in healthy and laminitic horses

    NARCIS (Netherlands)

    Wijnberg, I.D.; Hardeman, L C; van der Meij, B R; Back, Willem; Kolk, van der, J.H.

    2016-01-01

    BACKGROUND: In equine laminitis, the deep digital flexor muscle (DDFM) appears to have increased muscle force, but evidence-based confirmation is lacking. OBJECTIVES: The purpose of this study was to test if the DDFM of laminitic equines has an increased muscle force detectable by needle

  9. Two-dimensional pattern formation in ionic liquids confined between graphene walls.

    Science.gov (United States)

    Montes-Campos, Hadrián; Otero-Mato, José Manuel; Méndez-Morales, Trinidad; Cabeza, Oscar; Gallego, Luis J; Ciach, Alina; Varela, Luis M

    2017-09-20

    We perform molecular dynamics simulations of ionic liquids confined between graphene walls under a large variety of conditions (pure ionic liquids, mixtures with water and alcohols, mixtures with lithium salts and defective graphene walls). Our results show that the formation of striped and hexagonal patterns in the Stern layer can be considered as a general feature of ionic liquids at electrochemical interfaces, the transition between patterns being controlled by the net balance of charge in the innermost layer of adsorbed molecules. This explains previously reported experimental and computational results and, for the first time, why these pattern changes are triggered by any perturbation of the charge density at the innermost layer of the electric double layer (voltage and composition changes, and vacancies at the electrode walls, among others), which may help tuning electrode-ionic liquid interfaces. Using Monte Carlo simulations we show that such structures can be reproduced by a simple two-dimensional lattice model with only nearest-neighbour interactions, governed by highly screened ionic interactions and short-range and excluded volume interactions. We also show that the results of our simulations are consistent with those inferred from the Landau-Brazovskii theory of pattern formation in self-assembling systems. The presence of these patterns at the ionic liquid graphene-electrode interfaces may have a strong impact on the process of ionic transfer from the bulk mixtures to the electrodes, on the differential capacitance of the electrode-electrolyte double layer or on the rates of redox reactions at the electrodes, among other physicochemical properties, and is therefore an effect of great technological interest.

  10. Ca2+ uptake, Ca2+-ATPase activity, phosphoprotein formation and phosphate turnover in a microsomal fraction of smooth muscle.

    Science.gov (United States)

    Raeymaekers, L; Hasselbach, W

    1981-05-15

    Vesicles capable of phosphate-stimulated calcium uptake were isolated from the microsomal fraction of the smooth muscle of the pig stomach according to a previously described procedure which consists in increasing the density of the vesicles by loading them with calcium phosphate and isolating them by centrifugation [Raeymaekers, L., Agostini, B., and Hasselbach, W. (1981) Histochemistry, 70, 139--150]. These vesicles, which contain calcium phosphate deposits, are able to accumulate an additional amount of calcium. This calcium uptake is accompanied by calcium-stimulated ATPase activity and by the formation of an acid-stable phosphoprotein. The acid-denatured phosphoprotein is dephosphorylated by hydroxylamine, which indicates that an acylphosphate is formed. This phosphoprotein probably represents a phosphorylated transport intermediate similar to that seen with the Ca2+-ATPase of sarcoplasmic reticulum of skeletal muscle. As with the Ca2+-ATPase of sarcoplasmic reticulum vesicles, this vesicular fraction catalyses an exchange between inorganic phosphate and the gamma-phosphate of ATP (ATP-Pi exchange) which is dependent on the presence of intravesicular calcium, and an exchange of phosphate between ATP and ADP (ATP-ADP exchange). The results further indicate that the turnover rate of the calcium pump, calculated from the ratio of calcium-stimulated ATPase activity to the steady-state level of phosphoprotein, is similar to that of Ca2+-ATPase of sarcoplasmic reticulum of skeletal muscle.

  11. How the Propagation of Heat-Flux Modulations Triggers E × B Flow Pattern Formation

    Science.gov (United States)

    Kosuga, Yusuke

    2013-10-01

    Recently, a new class of E × B flow pattern, called an `` E × B staircase,'' was observed in a simulation study using the full- f flux driven GYSELA code. Here, E × B staircases are quasi-regular steady patterns of localized shear layers and temperature profile corrugations. The shear layers are interspaced between regions of turbulent avalanching of the size of several correlation length (~ 10Δc). In this work, a theory to describe the formation of such E × B staircases from a bath of stochastic avalanches is presented, based on analogy of staircase formation to jam formation in traffic flow. Namely, staircase formation is viewed as a heat flux ``jam'' that causes profile corrugation, which is analogous to a traffic jam that causes corrugations in the local car density in a traffic flow. To model such an effect in plasmas, a finite response time τ is introduced, during which instantaneous heat flux relaxes to the mean heat flux, determined by symmetry constraints. The response time introduced here is an analogue of drivers' response time in traffic flow dynamics. It is shown that the extended model describes a heat flux ``jam'' and profile corrugation, which appears as an instability, in analogy to the way a clustering instability leads to a traffic jam. Such local amplification of heat and profile corrugations can lead to the formation of E × B staircases. The scale length that gives the maximum growth rate falls in the mesoscale range and is comparable to the staircase step spacing. Present address: IAS and RIAM, Kyushu University, Japan.

  12. Pattern formation by a cell surface-associated morphogen in Myxococcus xanthus

    Science.gov (United States)

    Jelsbak, Lars; Søgaard-Andersen, Lotte

    2002-02-01

    In response to starvation, an unstructured population of identical Myxococcus xanthus cells rearranges into an asymmetric, stable pattern of multicellular fruiting bodies. Central to this pattern formation process are changes in organized cell movements from swarming to aggregation. Aggregation is induced by the cell surface-associated C-signal. To understand how aggregation is accomplished, we have analyzed how C-signal modulates cell behavior. We show that C-signal induces a motility response that includes increases in transient gliding speeds and in the duration of gliding intervals and decreases in stop and reversal frequencies. This response results in a switch in cell behavior from an oscillatory to a unidirectional type of behavior in which the net-distance traveled by a cell per minute is increased. We propose that the C-signal-dependent regulation of the reversal frequency is essential for aggregation and that the remaining C-signal-dependent changes in motility parameters contribute to aggregation by increasing the net-distance traveled by starving cells per minute. In our model for symmetry-breaking and aggregation, C-signal transmission is a local event involving direct contacts between cells that results in a global organization of cells. This pattern formation mechanism does not require a diffusible substance or other actions at a distance. Rather it depends on contact-induced changes in motility behavior to direct cells appropriately

  13. Clastic patterned ground in Lomonosov crater, Mars: examining fracture controlled formation mechanisms

    Science.gov (United States)

    Barrett, Alexander M.; Balme, Matthew R.; Patel, Manish R.; Hagermann, Axel

    2017-10-01

    The area surrounding Lomonosov crater on Mars has a high density of seemingly organised boulder patterns. These form seemingly sorted polygons and stripes within kilometre scale blockfields, patches of boulder strewn ground which are common across the Martian high latitudes. Several hypotheses have been suggested to explain the formation of clastic patterned ground on Mars. It has been proposed that these structures could have formed through freeze-thaw sorting, or conversely by the interaction of boulders with underlying fracture polygons. In this investigation a series of sites were examined to evaluate whether boulder patterns appear to be controlled by the distribution of underlying fractures and test the fracture control hypotheses for their formation. It was decided to focus on this suite of mechanisms as they are characterised by a clear morphological relationship, namely the presence of an underlying fracture network which can easily be evaluated over a large area. It was found that in the majority of examples at these sites did not exhibit fracture control. Although fractures were present at many sites there were very few sites where the fracture network appeared to be controlling the boulder distribution. In general these were not the sites with the best examples of organization, suggesting that the fracture control mechanisms are not the dominant geomorphic process organising the boulders in this area.

  14. Exploring the formation of focal adhesions on patterned surfaces using super-resolution imaging.

    Science.gov (United States)

    Chien, Fan-Ching; Kuo, Chiung Wen; Yang, Zong-Han; Chueh, Di-Yen; Chen, Peilin

    2011-10-17

    The formation of focal adhesions on various sizes of fibronectin patterns, ranging from 200 μm to 250 nm, was systematically investigated by total internal reflection fluorescence microscopy and super-resolution imaging. It was found that cells adhered to and spread on these micro/nanopatterns, forming focal adhesions. On a micrometer scale the shape of the focal adhesions was elongated. However, on the nanometer scale, the shape of focal adhesions became dotlike. To further explore the distribution of focal adhesion proteins formed on surfaces, a localization-based super-resolution imaging technique was employed in order to determine the position and density of vinculin proteins. A characteristic distance of 50 nm was found between vinculin molecules in the focal adhesions, which did not depend on the size of the fibronectin nanopatterns. This distance was found to be crucial for the formation of focal adhesions. In addition, the density of vinculin at the focal adhesions formed on the nanopatterns increased as the pattern size decreased. The density of the protein was found to be 425 ± 247, 584 ± 302, and 703 ± 305 proteins μm(-2) on the 600, 400, and 250 nm fibronectin patterns respectively. Whereas 226 ± 77 proteins μm(-2) was measured for the matured focal adhesions on homogeneous fibronectin coated substrates. The increase in vinculin density implies that an increase in mechanical load was applied to the focal adhesions formed on the smaller nanopatterns.

  15. Dissipative parametric modulation instability and pattern formation in nonlinear optical systems

    Science.gov (United States)

    Perego, A. M.; Tarasov, N.; Churkin, D. V.; Turitsyn, S. K.; Staliunas, K.

    2016-04-01

    We present the essential features of the dissipative parametric instability, in the universal complex Ginzburg- Landau equation. Dissipative parametric instability is excited through a parametric modulation of frequency dependent losses in a zig-zag fashion in the spectral domain. Such damping is introduced respectively for spectral components in the +ΔF and in the -ΔF region in alternating fashion, where F can represent wavenumber or temporal frequency depending on the applications. Such a spectral modulation can destabilize the homogeneous stationary solution of the system leading to growth of spectral sidebands and to the consequent pattern formation: both stable and unstable patterns in one- and in two-dimensional systems can be excited. The dissipative parametric instability provides an useful and interesting tool for the control of pattern formation in nonlinear optical systems with potentially interesting applications in technological applications, like the design of mode- locked lasers emitting pulse trains with tunable repetition rate; but it could also find realizations in nanophotonics circuits or in dissipative polaritonic Bose-Einstein condensates.

  16. Molecular dynamics of single-particle impacts predicts phase diagrams for large scale pattern formation.

    Science.gov (United States)

    Norris, Scott A; Samela, Juha; Bukonte, Laura; Backman, Marie; Djurabekova, Flyura; Nordlund, Kai; Madi, Charbel S; Brenner, Michael P; Aziz, Michael J

    2011-01-01

    Energetic particle irradiation can cause surface ultra-smoothening, self-organized nanoscale pattern formation or degradation of the structural integrity of nuclear reactor components. A fundamental understanding of the mechanisms governing the selection among these outcomes has been elusive. Here we predict the mechanism governing the transition from pattern formation to flatness using only parameter-free molecular dynamics simulations of single-ion impacts as input into a multiscale analysis, obtaining good agreement with experiment. Our results overturn the paradigm attributing these phenomena to the removal of target atoms via sputter erosion: the mechanism dominating both stability and instability is the impact-induced redistribution of target atoms that are not sputtered away, with erosive effects being essentially irrelevant. We discuss the potential implications for the formation of a mysterious nanoscale topography, leading to surface degradation, of tungsten plasma-facing fusion reactor walls. Consideration of impact-induced redistribution processes may lead to a new design criterion for stability under irradiation.

  17. Ordered nano-scale dimple pattern formation on a titanium alloy (Ti-6Al-4V

    Directory of Open Access Journals (Sweden)

    Yue Wang

    2012-09-01

    Full Text Available Due to the many applications of nanostructured surfaces – including in biomaterials – there is a strong interest in cost- and time-efficient methods for their fabrication. Previously, our group established a simple electrochemical method generating nanoscale patterns on large areas of a number of different metal surfaces. They consist of dimples that are around 6-10 nm deep and hexagonally closed packed with a tunable periodicity of around 50 nm. Ordering requires careful tuning of the surface chemistry, which makes the translation of these findings to multi-component alloys non-obvious. Here, we demonstrate for the first time that such a pattern can also be achieved on the surface of an alloy, namely Ti-6Al-4V. This alloy is of particular interest for biomedical implants. While dimple formation on the main component metals titanium and aluminum has previously been reported (albeit under conditions that differ from each other, we now also report dimple formation on pure vanadium surfaces to occur under very different conditions. Dimple formation occurs preferentially on the (dominant α-phase grains of the alloy. The size of dimples of the alloy material is subject to the electropolishing potential, electrolyte concentration and surface chemical composition, which gives us the opportunity to control the surface features. Since a main application of this alloy are biomedical implants, this level of control will be an important tool for accommodating cell growth.

  18. NFI-C2 temporal-spatial expression and cellular localization pattern during tooth formation.

    Science.gov (United States)

    Lamani, Ejvis; Gluhak-Heinrich, Jelica; MacDougall, Mary

    2015-12-01

    Currently, little is known regarding critical signaling pathways during later stages of tooth development, especially those associated with root formation. Nfi-c null mice, lacking molar roots, have implicated the transcription factor NFI-C as having an essential role in root development. Previously, we identified three NFI-C isoforms expressed in dental tissues with NFI-C2 being the major transcript. However, the expression pattern of the NFI-C2 protein is not characterized. In this study we performed in situ hybridization and immunohistochemistry using isoform specific probes. We show the production of a NFI-C2 peptide antibody, its characterization, the temporal-spatial expression pattern of the NFI-C2 protein during odontogenesis and sub-cellular localization in dental cells. Moderate NFI-C2 staining, as early as bud stage, was detected mostly in the condensing dental ectomesenchyme. This staining intensified within the dental pulp at later stages culminating in high expression in the dentin producing odontoblasts. The dental epithelium showed slight staining until cytodifferentiation of enamel organ into ameloblasts and stratum intermedium. During root formation NFI-C2 expression was high in the Hertwig's epithelial root sheath and later was found in the fully developed root and its supporting tissues. NFI-C2 cellular staining was cytosolic, associated with the Golgi, and nuclear. These data suggest a broader role for NFI-C during tooth formation than limited to root and periodontal ligament development. © 2015 Japanese Society of Developmental Biologists.

  19. How the propagation of heat-flux modulations triggers E × B flow pattern formation.

    Science.gov (United States)

    Kosuga, Y; Diamond, P H; Gürcan, O D

    2013-03-08

    We propose a novel mechanism to describe E×B flow pattern formation based upon the dynamics of propagation of heat-flux modulations. The E × B flows of interest are staircases, which are quasiregular patterns of strong, localized shear layers and profile corrugations interspersed between regions of avalanching. An analogy of staircase formation to jam formation in traffic flow is used to develop an extended model of heat avalanche dynamics. The extension includes a flux response time, during which the instantaneous heat flux relaxes to the mean heat flux, determined by symmetry constraints. The response time introduced here is the counterpart of the drivers' response time in traffic, during which drivers adjust their speed to match the background traffic flow. The finite response time causes the growth of mesoscale temperature perturbations, which evolve to form profile corrugations. The length scale associated with the maximum growth rate scales as Δ(2) ~ (v(thi)/λT(i))ρ(i)sqrt[χ(neo)τ], where λT(i) is a typical heat pulse speed, χ(neo) is the neoclassical thermal diffusivity, and τ is the response time of the heat flux. The connection between the scale length Δ(2) and the staircase interstep scale is discussed.

  20. GLUT11, but not GLUT8 or GLUT12, is expressed in human skeletal muscle in a fibre type-specific pattern

    DEFF Research Database (Denmark)

    Gaster, M; Handberg, A; Schürmann, A

    2004-01-01

    or amyotrophic lateral sclerosis (ALS) were studied. GLUT8 and 12 immunoreactivity was below detection level in both developing and adult muscle fibres. GLUT11 immunoreactivity, however, was present in slow-twitch muscle fibres, but not in fast twitch fibres. Since, in contrast, GLUT4 was expressed in all...... investigated muscle fibres, the pattern of expression of GLUT11 differs from that of GLUT4, suggesting a specialized function for GLUT11 with a regulation independent from that of GLUT4. Obesity, type-2 diabetes, training, conditions of de- and reinnervation (ALS) and regeneration (polymyositis) failed...... to induce GLUT8 or -12 expression. Likewise, the fibre type-dependent pattern of GLUT11 immunoreactivity was unaltered. However, some slow muscle fibres lose their GLUT11 immunoreactivity under regeneration. Our results indicate that GLUT11 immunoreactivity, in contrast to that of GLUT4, is expressed...

  1. Co-culture of vascular endothelial cells and smooth muscle cells by hyaluronic acid micro-pattern on titanium surface

    Science.gov (United States)

    Li, Jingan; Li, Guicai; Zhang, Kun; Liao, Yuzhen; Yang, Ping; Maitz, Manfred F.; Huang, Nan

    2013-05-01

    Micro-patterning as an effective bio-modification technique is increasingly used in the development of biomaterials with superior mechanical and biological properties. However, as of now, little is known about the simultaneous regulation of endothelial cells (EC) and smooth muscle cells (SMC) by cardiovascular implants. In this study, a co-culture system of EC and SMC was built on titanium surface by the high molecular weight hyaluronic acid (HMW-HA) micro-pattern. Firstly, the micro-pattern sample with a geometry of 25 μm wide HMW-HA ridges, and 25 μm alkali-activated Ti grooves was prepared by microtransfer molding (μTM) for regulating SMC morphology. Secondly, hyaluronidase was used to decompose high molecular weight hyaluronic acid into low molecular weight hyaluronic acid which could promote EC adhesion. Finally, the morphology of the adherent EC was elongated by the SMC micro-pattern. The surface morphology of the patterned Ti was imaged by SEM. The existence of high molecular weight hyaluronic acid on the modified Ti surface was demonstrated by FTIR. The SMC micro-pattern and EC/SMC co-culture system were characterized by immunofluorescence microscopy. The nitric oxide release test and cell retention calculation were used to evaluate EC function on inhibiting hyperplasia and cell shedding, respectively. The results indicate that EC in EC/SMC co-culture system displayed a higher NO release and cell retention compared with EC cultured alone. It can be suggested that the EC/SMC co-culture system possessed superiority to EC cultured alone in inhibiting hyperplasia and cell shedding at least in a short time of 24 h.

  2. Patterns of muscle activation during generalized tonic and tonic–clonic epileptic seizures

    DEFF Research Database (Denmark)

    Conradsen, Isa; Wolf, Peter; Sams, Thomas

    2011-01-01

    was recorded from the deltoid muscles, on both sides, during 63 seizures from 20 patients with epilepsy (10 with generalized tonic and 10 with tonic–clonic seizures). Twenty age‐ and gender‐matched normal controls simulated 100 generalized tonic seizures. To characterize the signal properties we calculated...... the root mean square (RMS) of the amplitudes, the median frequency (MF), and the coherence. Based on the spectrograms of both epileptic and simulated seizures, we chose to determine the relative spectral power (RP) in the higher (100–500 Hz) frequency domain. Key Findings: During the tonic seizures...

  3. Muscle involvement during intermittent contraction patterns with different target force feedback modes

    DEFF Research Database (Denmark)

    Sjøgaard, G; Jørgensen, L V; Ekner, D

    2000-01-01

    and following 30 min of intermittent contractions showed larger fatigue development with proprioceptive feedback than visual feedback. Also rating of perceived exertion increased more during proprioceptive feedback than visual feedback. This may in part be explained by small differences in the mechanics during...... timing and force level is generally not specified. DESIGN: Repeated measure design in which six subjects in randomized order performed two experimental conditions only differing in feedback mode. METHODS: Intermittent static elbow flexion was performed against either a fixed-force transducer (visual...... and consequently the development muscle fatigue and disorders....

  4. Active pauses induce more variable electromyographic pattern of the trapezius muscle activity during computer work

    DEFF Research Database (Denmark)

    Samani, Afshin; Holtermann, Andreas; Søgaard, Karen

    2009-01-01

    , with passive (relax) and active (30% maximum voluntary contraction of shoulder elevation) pauses given every 2 min at two different work paces (low/high). Bipolar SEMG from four parts of the trapezius muscle was recorded. The relative rest time was higher for the lower parts compared with the upper......The aim of this laboratory study was to evaluate effects of active and passive pauses and investigate the distribution of the trapezius surface electromyographic (SEMG) activity during computer mouse work. Twelve healthy male subjects performed four sessions of computer work for 10 min in one day...... of the trapezius (pactive pause compared with passive one (p

  5. Disappearing scales in carps: re-visiting Kirpichnikov's model on the genetics of scale pattern formation.

    Directory of Open Access Journals (Sweden)

    Laura Casas

    Full Text Available The body of most fishes is fully covered by scales that typically form tight, partially overlapping rows. While some of the genes controlling the formation and growth of fish scales have been studied, very little is known about the genetic mechanisms regulating scale pattern formation. Although the existence of two genes with two pairs of alleles (S&s and N&n regulating scale coverage in cyprinids has been predicted by Kirpichnikov and colleagues nearly eighty years ago, their identity was unknown until recently. In 2009, the 'S' gene was found to be a paralog of fibroblast growth factor receptor 1, fgfr1a1, while the second gene called 'N' has not yet been identified. We re-visited the original model of Kirpichnikov that proposed four major scale pattern types and observed a high degree of variation within the so-called scattered phenotype due to which this group was divided into two sub-types: classical mirror and irregular. We also analyzed the survival rates of offspring groups and found a distinct difference between Asian and European crosses. Whereas nude × nude crosses involving at least one parent of Asian origin or hybrid with Asian parent(s showed the 25% early lethality predicted by Kirpichnikov (due to the lethality of the NN genotype, those with two Hungarian nude parents did not. We further extended Kirpichnikov's work by correlating changes in phenotype (scale-pattern to the deformations of fins and losses of pharyngeal teeth. We observed phenotypic changes which were not restricted to nudes, as described by Kirpichnikov, but were also present in mirrors (and presumably in linears as well; not analyzed in detail here. We propose that the gradation of phenotypes observed within the scattered group is caused by a gradually decreasing level of signaling (a dose-dependent effect probably due to a concerted action of multiple pathways involved in scale formation.

  6. Disappearing scales in carps: re-visiting Kirpichnikov's model on the genetics of scale pattern formation.

    Science.gov (United States)

    Casas, Laura; Szűcs, Réka; Vij, Shubha; Goh, Chin Heng; Kathiresan, Purushothaman; Németh, Sándor; Jeney, Zsigmond; Bercsényi, Miklós; Orbán, László

    2013-01-01

    The body of most fishes is fully covered by scales that typically form tight, partially overlapping rows. While some of the genes controlling the formation and growth of fish scales have been studied, very little is known about the genetic mechanisms regulating scale pattern formation. Although the existence of two genes with two pairs of alleles (S&s and N&n) regulating scale coverage in cyprinids has been predicted by Kirpichnikov and colleagues nearly eighty years ago, their identity was unknown until recently. In 2009, the 'S' gene was found to be a paralog of fibroblast growth factor receptor 1, fgfr1a1, while the second gene called 'N' has not yet been identified. We re-visited the original model of Kirpichnikov that proposed four major scale pattern types and observed a high degree of variation within the so-called scattered phenotype due to which this group was divided into two sub-types: classical mirror and irregular. We also analyzed the survival rates of offspring groups and found a distinct difference between Asian and European crosses. Whereas nude × nude crosses involving at least one parent of Asian origin or hybrid with Asian parent(s) showed the 25% early lethality predicted by Kirpichnikov (due to the lethality of the NN genotype), those with two Hungarian nude parents did not. We further extended Kirpichnikov's work by correlating changes in phenotype (scale-pattern) to the deformations of fins and losses of pharyngeal teeth. We observed phenotypic changes which were not restricted to nudes, as described by Kirpichnikov, but were also present in mirrors (and presumably in linears as well; not analyzed in detail here). We propose that the gradation of phenotypes observed within the scattered group is caused by a gradually decreasing level of signaling (a dose-dependent effect) probably due to a concerted action of multiple pathways involved in scale formation.

  7. Disappearing scales in carps: Re-visiting Kirpichnikov's model on the genetics of scale pattern formation

    KAUST Repository

    Casas, Laura

    2013-12-30

    The body of most fishes is fully covered by scales that typically form tight, partially overlapping rows. While some of the genes controlling the formation and growth of fish scales have been studied, very little is known about the genetic mechanisms regulating scale pattern formation. Although the existence of two genes with two pairs of alleles (S&s and N&n) regulating scale coverage in cyprinids has been predicted by Kirpichnikov and colleagues nearly eighty years ago, their identity was unknown until recently. In 2009, the \\'S\\' gene was found to be a paralog of fibroblast growth factor receptor 1, fgfr1a1, while the second gene called \\'N\\' has not yet been identified. We re-visited the original model of Kirpichnikov that proposed four major scale pattern types and observed a high degree of variation within the so-called scattered phenotype due to which this group was divided into two sub-types: classical mirror and irregular. We also analyzed the survival rates of offspring groups and found a distinct difference between Asian and European crosses. Whereas nude x nude crosses involving at least one parent of Asian origin or hybrid with Asian parent(s) showed the 25% early lethality predicted by Kirpichnikov (due to the lethality of the NN genotype), those with two Hungarian nude parents did not. We further extended Kirpichnikov\\'s work by correlating changes in phenotype (scale-pattern) to the deformations of fins and losses of pharyngeal teeth. We observed phenotypic changes which were not restricted to nudes, as described by Kirpichnikov, but were also present in mirrors (and presumably in linears as well; not analyzed in detail here). We propose that the gradation of phenotypes observed within the scattered group is caused by a gradually decreasing level of signaling (a dosedependent effect) probably due to a concerted action of multiple pathways involved in scale formation. 2013 Casas et al.

  8. Pattern formation during the evaporation of a colloidal nanoliter drop: a numerical and experimental study

    CERN Document Server

    Bhardwaj, Rajneesh; Attinger, Daniel

    2010-01-01

    An efficient way to precisely pattern particles on solid surfaces is to dispense and evaporate colloidal drops, as for bioassays. The dried deposits often exhibit complex structures exemplified by the coffee ring pattern, where most particles have accumulated at the periphery of the deposit. In this work, the formation of deposits during the drying of nanoliter colloidal drops on a flat substrate is investigated numerically and experimentally. A finite-element numerical model is developed that solves the Navier-Stokes, heat and mass transport equations in a Lagrangian framework. The diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary condition for the evaporative flux at the droplet-air interface. Laplace stresses and thermal Marangoni stresses are accounted for. The particle concentration is tracked by solving a continuum advection-diffusion equation. Wetting line motion and the interaction of the free surface of the drop with the growing deposit are modeled based on crite...

  9. Polymer Wall Formation Using Liquid-Crystal/Polymer Phase Separation Induced on Patterned Polyimide Films

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    We could form lattice-shaped polymer walls in a liquid crystal (LC) layer through the thermal phase separation of an LC/polystyrene solution between substrates with polyimide films etched by short-wavelength ultraviolet irradiation using a photomask. The LC wetting difference between the polyimide and substrate surfaces caused the coalescence of growing LC droplets on patterned polyimide films with the progress of phase separation. Consequently, polymer walls were formed on substrate surface areas without polyimide films. The shape of the polymer wall formed became sharp with the use of rubbed polyimide films because the nucleation of growing LC droplets concentrated on the patterned polyimide films. It is thought that the increase in the alignment order of LC molecules in the solution near the rubbed polyimide films promotes the formation of LC molecular aggregation, which becomes the growth nuclei of LC droplets.

  10. Three dimensional simulations of pattern formation during high-pressure, freely localized microwave breakdown in air

    Energy Technology Data Exchange (ETDEWEB)

    Kourtzanidis, K., E-mail: Konstantinos.Kourtzanidis@onera.fr; Boeuf, J. P. [LAPLACE (Laboratoire Plasma et Conversion d' Energie), Université de Toulouse, UPS, INPT, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Rogier, F. [ONERA - The French Aerospace Lab, 2 Avenue édouard Belin, 31000 Toulouse (France)

    2014-12-15

    Recent experiments have demonstrated that a freely localized 100 GHz microwave discharge can propagate towards the microwave source with high speed, forming a complex pattern of self-organized filaments. We present three-dimensional simulations of the formation and propagation of such patterns that reveal more information on their nature and interaction with the electromagnetic waves. The developed three-dimensional Maxwell-plasma solver permits the study of different forms of incident field polarization. Results for linear and circular polarization of the wave are presented and comparisons with recent experiments show a good overall agreement. The three dimensional simulations provide a quantitative analysis of the parameters controlling the time and length scales of the strongly non-linear plasma dynamics and could be useful for potential microwave plasma applications such as aerodynamic flow and combustion control.

  11. Pattern Formation in a Cross-Diffusive Ratio-Dependent Predator-Prey Model

    Directory of Open Access Journals (Sweden)

    Xinze Lian

    2012-01-01

    Full Text Available This paper presents a theoretical analysis of evolutionary process that involves organisms distribution and their interaction of spatial distribution of the species with self- and cross-diffusion in a Holling-III ratio-dependent predator-prey model. The diffusion instability of the positive equilibrium of the model with Neumann boundary conditions is discussed. Furthermore, we present novel numerical evidence of time evolution of patterns controlled by self- and cross-diffusion in the model and find that the model dynamics exhibits a cross-diffusion controlled formation growth to spots, stripes, and spiral wave pattern replication, which show that reaction-diffusion model is useful to reveal the spatial predation dynamics in the real world.

  12. Formation of mixed and patterned self-assembled films of alkylphosphonates on commercially pure titanium surfaces

    Science.gov (United States)

    Rudzka, Katarzyna; Sanchez Treviño, Alda Y.; Rodríguez-Valverde, Miguel A.; Cabrerizo-Vílchez, Miguel A.

    2016-12-01

    Titanium is extensively employed in biomedical devices, in particular as implant. The self-assembly of alkylphosphonates on titanium surfaces enable the specific adsorption of biomolecules to adapt the implant response against external stimuli. In this work, chemically-tailored cpTi surfaces were prepared by self-assembly of alkylphosphonate molecules. By bringing together attributes of two grafting molecules, aqueous mixtures of two alkylphosphonates were used to obtain mixed self-assembled films. Single self-assembled films were also altered by laser abrasion to produce chemically patterned cpTi surfaces. Both mixed and patterned self-assembled films were confirmed by AFM, ESEM and X-ray photoelectron spectroscopy. Water contact angle measurements also revealed the composition of the self-assembly films. Chemical functionalization with two grafting phosphonate molecules and laser surface engineering may be combined to guide the bone-like formation on cpTi, and the future biological response in the host.

  13. Patterns formations in a diffusive ratio-dependent predator-prey model of interacting populations

    Science.gov (United States)

    Camara, B. I.; Haque, M.; Mokrani, H.

    2016-11-01

    The present investigation deals with the analysis of the spatial pattern formation of a diffusive predator-prey system with ratio-dependent functional response involving the influence of intra-species competition among predators within two-dimensional space. The appropriate condition of Turing instability around the interior equilibrium point of the present model has been determined. The emergence of complex patterns in the diffusive predator-prey model is illustrated through numerical simulations. These results are based on the existence of bifurcations of higher codimension such as Turing-Hopf, Turing-Saddle-node, Turing-Transcritical bifurcation, and the codimension- 3 ​Turing-Takens-Bogdanov bifurcation. The paper concludes with discussions of our results in ecology.

  14. Continuous fine pattern formation by screen-offset printing using a silicone blanket

    Science.gov (United States)

    Nomura, Ken-ichi; Kusaka, Yasuyuki; Ushijima, Hirobumi; Nagase, Kazuro; Ikedo, Hiroaki; Mitsui, Ryosuke; Takahashi, Seiya; Nakajima, Shin-ichiro; Iwata, Shiro

    2014-09-01

    Screen-offset printing combines screen-printing on a silicone blanket with transference of the print from the blanket to a substrate. The blanket absorbs organic solvents in the ink, and therefore, the ink does not disperse through the material. This prevents blurring and allows fine patterns with widths of a few tens of micrometres to be produced. However, continuous printing deteriorates the pattern’s shape, which may be a result of decay in the absorption abilities of the blanket. Thus, we have developed a new technique for refreshing the blanket by substituting high-boiling-point solvents present on the blanket surface with low-boiling-point solvents. We analyse the efficacy of this technique, and demonstrate continuous fine pattern formation for 100 screen-offset printing processes.

  15. Statistical analysis and modeling of collective cell motion and pattern formation

    Science.gov (United States)

    Czirok, Andras; Szabo, Andras

    2009-03-01

    Cell motility and its guidance through cell-cell contacts is instrumental in vasculogenesis and in several other morphogenic processes as well. During vasculogenesis multicellular sprouts invade rapidly into avascular areas, eventually creating an interconnected network pattern. Epithelial cell sheets migrate during organogenesis or wound healing. These phenomena were studied with time-lapse microscopy both in vivo and in vitro. Statistical analysis of cell trajectories reveals that motile confluent cultures may behave either as vortical fluids or as deforming elastic sheets. The observed flow fields and pattern formation can be explained by our generalized cellular Potts model -- representing cell polarization and self-propulsion, links between the cytoskeleton of adjacent cells as well as an asymmetric preferential attraction to the surface of adjacent cells.

  16. Mechanisms for spatio-temporal pattern formation in highway traffic models.

    Science.gov (United States)

    Wilson, R Eddie

    2008-06-13

    A key qualitative requirement for highway traffic models is the ability to replicate a type of traffic jam popularly referred to as a phantom jam, shock wave or stop-and-go wave. Despite over 50 years of modelling, the precise mechanisms for the generation and propagation of stop-and-go waves and the associated spatio-temporal patterns are in dispute. However, the increasing availability of empirical datasets, such as those collected from motorway incident detection and automatic signalling system (MIDAS) inductance loops in the UK or the next-generation simulation trajectory data (NGSIM) project in the USA, means that we can expect to resolve these questions definitively in the next few years. This paper will survey the essence of the competing explanations of highway traffic pattern formation and introduce and analyse a new mechanism, based on dynamical systems theory and bistability, which can help resolve the conflict.

  17. Pattern formation in a complex Swift-Hohenberg equation with phase bistability

    CERN Document Server

    de Valcárcel, Manuel Martínez-Quesada Germán J

    2016-01-01

    We study pattern formation in a complex Swift Hohenberg equation with phase-sensitive (parametric) gain. Such an equation serves as a universal order parameter equation describing the onset of spontaneous oscillations in extended systems submitted to a kind of forcing dubbed rocking when the instability is towards long wavelengths. Applications include two-level lasers and photorefractive oscillators. Under rocking, the original continuous phase symmetry of the system is replaced by a discrete one, so that phase bistability emerges. This leads to the spontaneous formation of phase-locked spatial structures like phase domains and dark-ring (phase-) cavity solitons. Stability of the homogeneous solutions is studied and numerical simulations are made covering all the dynamical regimes of the model, which turn out to be very rich. Formal derivations of the rocked complex Swift-Hohenberg equation, using multiple scale techniques, are given for the two-level laser and the photorefractive oscillator.

  18. E × B shear pattern formation by radial propagation of heat flux waves

    Energy Technology Data Exchange (ETDEWEB)

    Kosuga, Y., E-mail: kosuga@riam.kyushu-u.ac.jp [WCI Center for Fusion Theory, NFRI, Daejeon (Korea, Republic of); IAS and RIAM, Kyushu University, Fukuoka (Japan); Diamond, P. H. [WCI Center for Fusion Theory, NFRI, Daejeon (Korea, Republic of); CASS and CMTFO, University of California, San Diego, California 92093 (United States); Dif-Pradalier, G. [CEA, IRFM, Paul-lez-Durance Cedex (France); Gürcan, Ö. D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Palaiseau (France)

    2014-05-15

    A novel theory to describe the formation of E×B flow patterns by radially propagating heat flux waves is presented. A model for heat avalanche dynamics is extended to include a finite delay time between the instantaneous heat flux and the mean flux, based on an analogy between heat avalanche dynamics and traffic flow dynamics. The response time introduced here is an analogue of the drivers' response time in traffic dynamics. The microscopic foundation for the time delay is the time for mixing of the phase space density. The inclusion of the finite response time changes the model equation for avalanche dynamics from Burgers equation to a nonlinear telegraph equation. Based on the telegraph equation, the formation of heat flux jams is predicted. The growth rate and typical interval of jams are calculated. The connection of the jam interval to the typical step size of the E×B staircase is discussed.

  19. E × B shear pattern formation by radial propagation of heat flux wavesa)

    Science.gov (United States)

    Kosuga, Y.; Diamond, P. H.; Dif-Pradalier, G.; Gürcan, Ã.-. D.

    2014-05-01

    A novel theory to describe the formation of E ×B flow patterns by radially propagating heat flux waves is presented. A model for heat avalanche dynamics is extended to include a finite delay time between the instantaneous heat flux and the mean flux, based on an analogy between heat avalanche dynamics and traffic flow dynamics. The response time introduced here is an analogue of the drivers' response time in traffic dynamics. The microscopic foundation for the time delay is the time for mixing of the phase space density. The inclusion of the finite response time changes the model equation for avalanche dynamics from Burgers equation to a nonlinear telegraph equation. Based on the telegraph equation, the formation of heat flux jams is predicted. The growth rate and typical interval of jams are calculated. The connection of the jam interval to the typical step size of the E ×B staircase is discussed.

  20. Pattern formation in polymerising actin flocks: spirals, spots and waves without nonlinear chemistry

    CERN Document Server

    Goff, Thomas Le; Marenduzzo, Davide

    2016-01-01

    We propose a model solely based on actin treadmilling and polymerisation which describes many characteristic states of actin wave formation: spots, spirals and travelling waves. In our model, as in experiments on cell recovering motility following actin depolymerisation, we choose an isotropic low density initial condition; polymerisation of actin filaments then raises the density towards the Onsager threshold where they align. We show that this alignment, in turn, destabilizes the isotropic phase and generically induces transient actin spots or spirals as part of the dynamical pathway towards a polarized phase which can either be uniform or consist of a series of actin-wave trains (flocks). Our results uncover a universal route to actin wave formation in the absence of any system specific nonlinear biochemistry, and it may help understand the mechanism underlying the observation of actin spots and waves in vivo. They also suggest a minimal setup to design similar patterns in vitro.