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Sample records for cerebellum granular layer

  1. Computational Architecture of the Granular Layer of Cerebellum-Like Structures.

    Bratby, Peter; Sneyd, James; Montgomery, John

    2017-02-01

    In the adaptive filter model of the cerebellum, the granular layer performs a recoding which expands incoming mossy fibre signals into a temporally diverse set of basis signals. The underlying neural mechanism is not well understood, although various mechanisms have been proposed, including delay lines, spectral timing and echo state networks. Here, we develop a computational simulation based on a network of leaky integrator neurons, and an adaptive filter performance measure, which allows candidate mechanisms to be compared. We demonstrate that increasing the circuit complexity improves adaptive filter performance, and relate this to evolutionary innovations in the cerebellum and cerebellum-like structures in sharks and electric fish. We show how recurrence enables an increase in basis signal duration, which suggest a possible explanation for the explosion in granule cell numbers in the mammalian cerebellum.

  2. A realistic large-scale model of the cerebellum granular layer predicts circuit spatio-temporal filtering properties

    Sergio Solinas

    2010-05-01

    Full Text Available The way the cerebellar granular layer transforms incoming mossy fiber signals into new spike patterns to be related to Purkinje cells is not yet clear. Here, a realistic computational model of the granular layer was developed and used to address four main functional hypotheses: center-surround organization, time-windowing, high-pass filtering in responses to spike bursts and coherent oscillations in response to diffuse random activity. The model network was activated using patterns inspired by those recorded in vivo. Burst stimulation of a small mossy fiber bundle resulted in granule cell bursts delimited in time (time windowing and space (center-surround by network inhibition. This burst-burst transmission showed marked frequency-dependence configuring a high-pass filter with cut-off frequency around 100 Hz. The contrast between center and surround properties was regulated by the excitatory-inhibitory balance. The stronger excitation made the center more responsive to 10-50 Hz input frequencies and enhanced the granule cell output (with spike occurring earlier and with higher frequency and number compared to the surround. Finally, over a certain level of mossy fiber background activity, the circuit generated coherent oscillations in the theta-frequency band. All these processes were fine-tuned by NMDA and GABA-A receptor activation and neurotransmitter vesicle cycling in the cerebellar glomeruli. This model shows that available knowledge on cellular mechanisms is sufficient to unify the main functional hypotheses on the cerebellum granular layer and suggests that this network can behave as an adaptable spatio-temporal filter coordinated by theta-frequency oscillations.

  3. Deleting the Arntl clock gene in the granular layer of the mouse cerebellum

    Bering, Tenna; Carstensen, Mikkel Bloss; Rath, Martin Fredensborg

    2017-01-01

    nucleus. It has been suggested that the cerebellar circadian oscillator is involved in food anticipation, but direct molecular evidence of the role of the circadian oscillator of the cerebellar cortex is currently unavailable. To investigate the hypothesis that the circadian oscillator of the cerebellum...... is involved in circadian physiology and food anticipation, we therefore by use of Cre-LoxP technology generated a conditional knockout mouse with the core clock gene Arntl deleted specifically in granule cells of the cerebellum, since expression of clock genes in the cerebellar cortex is mainly located...

  4. Activation of the CREB/c-Fos Pathway during Long-Term Synaptic Plasticity in the Cerebellum Granular Layer

    Daniela Gandolfi

    2017-06-01

    Full Text Available The induction of long-term potentiation and depression (LTP and LTD is thought to trigger gene expression and protein synthesis, leading to consolidation of synaptic and neuronal changes. However, while LTP and LTD have been proposed to play important roles for sensori-motor learning in the cerebellum granular layer, their association with these mechanisms remained unclear. Here, we have investigated phosphorylation of the cAMP-responsive element binding protein (CREB and activation of the immediate early gene c-Fos pathway following the induction of synaptic plasticity by theta-burst stimulation (TBS in acute cerebellar slices. LTP and LTD were localized using voltage-sensitive dye imaging (VSDi. At two time points following TBS (15 min and 120 min, corresponding to the early and late phases of plasticity, slices were fixed and processed to evaluate CREB phosphorylation (P-CREB and c-FOS protein levels, as well as Creb and c-Fos mRNA expression. High levels of P-CREB and Creb/c-Fos were detected before those of c-FOS, as expected if CREB phosphorylation triggered gene expression followed by protein synthesis. No differences between control slices and slices stimulated with TBS were observed in the presence of an N-methyl-D-aspartate receptor (NMDAR antagonist. Interestingly, activation of the CREB/c-Fos system showed a relevant degree of colocalization with long-term synaptic plasticity. These results show that NMDAR-dependent plasticity at the cerebellum input stage bears about transcriptional and post-transcriptional processes potentially contributing to cerebellar learning and memory consolidation.

  5. Apoptosis of Purkinje and granular cells of the cerebellum following chronic ethanol intake.

    Oliveira, Suelen A; Chuffa, Luiz Gustavo A; Fioruci-Fontanelli, Beatriz Aparecida; Lizarte Neto, Fermino Sanches; Novais, Paulo Cezar; Tirapelli, Luiz Fernando; Oishi, Jorge Camargo; Takase, Luiz Fernando; Stefanini, Maira Aparecida; Martinez, Marcelo; Martinez, Francisco Eduardo

    2014-12-01

    Ethanol alters motricity, learning, cognition, and cellular metabolism in the cerebellum. We evaluated the effect of ethanol on apoptosis in Golgi, Purkinje, and granule cells of the cerebellum in adult rats. There were two groups of 20 rats: a control group that did not consume ethanol and an experimental group of UChA rats that consumed ethanol at 10% (cerebellum of adult UChA rats.

  6. Molecular layer interneurons of the cerebellum: developmental and morphological aspects.

    Sotelo, Constantino

    2015-10-01

    During the past 25 years, our knowledge on the development of basket and stellate cells (molecular layer interneurons [MLIs]) has completely changed, not only regarding their origin from the ventricular zone, corresponding to the primitive cerebellar neuroepithelium, instead of the external granular layer, but above all by providing an almost complete account of the genetic regulations (transcription factors and other genes) involved in their differentiation and synaptogenesis. Moreover, it has been shown that MLIs' precursors (dividing neuroblasts) and not young postmitotic neurons, as in other germinal neuroepithelia, leave the germinative zone and migrate all along a complex and lengthy path throughout the presumptive cerebellar white matter, which provides suitable niches exerting epigenetic influences on their ultimate neuronal identities. Recent studies carried out on the anatomical-functional properties of adult MLIs emphasize the importance of these interneurons in regulating PC inhibition, and point out the crucial role played by electrical synaptic transmission between MLIs as well as ephaptic interactions between them and Purkinje cells at the pinceaux level, in the regulation of this inhibition.

  7. A hybrid model for the computationally-efficient simulation of the cerebellar granular layer

    Anna eCattani

    2016-04-01

    Full Text Available The aim of the present paper is to efficiently describe the membrane potential dynamics of neural populations formed by species having a high density difference in specific brain areas. We propose a hybrid model whose main ingredients are a conductance-based model (ODE system and its continuous counterpart (PDE system obtained through a limit process in which the number of neurons confined in a bounded region of the brain tissue is sent to infinity. Specifically, in the discrete model, each cell is described by a set of time-dependent variables, whereas in the continuum model, cells are grouped into populations that are described by a set of continuous variables.Communications between populations, which translate into interactions among the discrete and the continuous models, are the essence of the hybrid model we present here. The cerebellum and cerebellum-like structures show in their granular layer a large difference in the relative density of neuronal species making them a natural testing ground for our hybrid model. By reconstructing the ensemble activity of the cerebellar granular layer network and by comparing our results to a more realistic computational network, we demonstrate that our description of the network activity, even though it is not biophysically detailed, is still capable of reproducing salient features of neural network dynamics. Our modeling approach yields a significant computational cost reduction by increasing the simulation speed at least $270$ times. The hybrid model reproduces interesting dynamics such as local microcircuit synchronization, traveling waves, center-surround and time-windowing.

  8. The evolution of the vertebrate cerebellum: absence of a proliferative external granule layer in a basal ray-finned fish

    Butts, Thomas; Modrell, Melinda S.; Baker, Clare V. H.; Wingate, Richard J. T.

    2014-01-01

    The cerebellum represents one of the most morphologically variable structures in the vertebrate brain. To shed light on its evolutionary history, we have examined the molecular anatomy and proliferation of the developing cerebellum of the North American paddlefish, Polyodon spathula. Absence of an external proliferative cerebellar layer and the restriction of Atonal1 expression to the rhombic lip and valvular primordium demonstrate that transit amplification in a cerebellar external germinal ...

  9. Granular nanocrystalline zirconia electrolyte layers deposited on porous SOFC cathode substrates

    Seydel, Johannes; Becker, Michael; Ivers-Tiffee, Ellen; Hahn, Horst

    2009-01-01

    Thin granular yttria-stabilized zirconia (YSZ) electrolyte layers were prepared by chemical vapor synthesis and deposition (CVD/CVS) on a porous substoichiometric lanthanum-strontium-manganite (ULSM) solid oxide fuel cell cathode substrate. The substrate porosity was optimized with a screen printed fine porous buffer layer. Structural analysis by scanning electron microscopy showed a homogeneous, granular nanocrystalline layer with a microstructure that was controlled via reactor settings. The CVD/CVS gas-phase process enabled the deposition of crack-free granular YSZ films on porous ULSM substrates. The electrolyte layers characterized with impedance spectroscopy exhibited enhanced grain boundary conductivity.

  10. The emotional cerebellum.

    Strata, Piergiorgio

    2015-10-01

    Great attention has been given so far to cerebellar control of posture and of skilled movements despite the well-demonstrated interconnections between the cerebellum and the autonomic nervous system. Here is a review of the link between these two structures and a report on the recently acquired evidence for its involvement in the world of emotions. In rodents, the reversible inactivation of the vermis during the consolidation or the reconsolidation period hampers the retention of the fear memory trace. In this region, there is a long-term potentiation of both the excitatory synapses between the parallel fibres and the Purkinje cells and of the feed-forward inhibition mediated by molecular layer interneurons. This concomitant potentiation ensures the temporal fidelity of the system. Additional contacts between mossy fibre terminals and Golgi cells provide morphological evidence of the potentiation of another feed-forward inhibition in the granular layer. Imaging experiments show that also in humans the cerebellum is activated during mental recall of emotional personal episodes and during learning of a conditioned or unconditioned association involving emotions. The vermis participates in fear learning and memory mechanisms related to the expression of autonomic and motor responses of emotions. In humans, the cerebellar hemispheres are also involved at a higher emotional level. The importance of these findings is evident when considering the cerebellar malfunctioning in psychiatric diseases like autism and schizophrenia which are characterized behaviourally by emotion processing impairments.

  11. A robot conditioned reflex system modeled after the cerebellum.

    Albus, J. S.

    1972-01-01

    Reduction of a theory of cerebellar function to computer software for the control of a mechanical manipulator. This reduction is achieved by considering the cerebellum, along with the higher-level brain centers which control it, as a type of finite-state machine with input entering the cerebellum via mossy fibers from the periphery and output from the cerebellum occurring via Purkinje cells. It is hypothesized that the cerebellum learns by an error-correction system similar to Perceptron training algorithms. An electromechanical model of the cerebellum is then developed for the control of a mechanical arm. The problem of modeling the granular layer which selects the set of parallel fibers which are active at any instant of time is considered, and a relevance matrix is constructed to model the relative degree of influence which mossy fibers from the various joints have on the sets of granule cells unique to each joint.

  12. Influence of Subgrade and Unbound Granular Layers Stiffness on Fatigue Life of Hot Mix Asphalts - HMA

    Hugo A. Rondón-Quintana

    2013-11-01

    Full Text Available The mainly factors studied to predict fatigue life of hot mix asphalt-HMA in flexible pavements are the loading effect, type of test, compaction methods, design parameters of HMA (e.g., particle size and size distribution curve, fine content, type of bitumen and the variables associated with the environment (mainly moisture, temperature, aging. This study evaluated through a computer simulation, the influence of the granular layers and subgrade on the fatigue life of asphalt layers in flexible pavement structures. Mechanics parameters of granular layers of subgrade, base and subbase were obtained using the mathematical equations currently used for this purpose in the world. The emphasis of the study was the city of Bogotá, where the average annual temperature is 14°C and soils predominantly clay, generally experience CBR magnitudes between 1% and 4%. General conclusion: stiffness of the granular layers and subgrade significantly affect the fatigue resistance of HMA mixtures. Likewise, the use of different equations reported in reference literature in order to characterize granular layers may vary the fatigue life between 4.6 and 48.5 times, varying the thickness of the pavement layers in the design.

  13. The evolution of the vertebrate cerebellum: absence of a proliferative external granule layer in a non-teleost ray-finned fish

    Butts, Thomas; Modrell, Melinda Sue; Baker, Clare Victoria; Wingate, Richard JT

    2014-01-01

    The cerebellum represents one of the most morphologically variable structures in the vertebrate brain. To shed light on its evolutionary history, we have examined the molecular anatomy and proliferation of the developing cerebellum of the North American paddlefish, Polyodon spathula. Absence of an external proliferative cerebellar layer and the restriction of Atonal1 expression to the rhombic lip and valvular primordium demonstrate that transit amplification in a cerebellar external germinal ...

  14. INVESTIGATION OF INNER SHEAR RESISTANCE OF GEOGRIDS BUILT UNDER GRANULAR PROTECTION LAYERS AND RAILWAY BALLAST

    Sz. Fischer

    2015-10-01

    Full Text Available Purpose. Using adequate granular materials and layer structures in the railway super- and substructure is able to stabilise railway track geometry. For this purpose special behaviour of above materials has to be determined, e.g. inner shear resistance. Inner shear resistance of granular media with and without geogrid reinforcement in different depths is not known yet. Methodology. The author developed a special laboratory method to measure and define inner shear resistance of granular materials, it is called «multi-level shear box test». This method is adequate to determine inner shear resistance (pushing force vs. depth (distance from the «zero» surface. Two different granular materials: andesite railway ballast (31.5/63 mm and andesite railway protection layer material (0/56 mm, and seven different types of geogrids (GG1…GG7 were used during the tests. Findings. Values of inner shear resistance functions of andesite railway ballast without geogrid reinforcement and reinforced with different types of geogrids and andesite granular protection layer in function of the vertical distance from the geogrid plane were determined with multi-layer shear box tests when the material aggregation is uncompacted and compacted. Only the compacted sample was tested in case of the 0/56 mm protection layer. Cubic polynomial regression functions fitted on the mean values of the measurements are described graphically. Determination coefficients with values of R2>0.97 were resulted in all the cases of regression functions. Based on the polynomial regression functions fitted on the mean values of the test results, three increasing factors were determined in function of the distance measured from the geogrid. Increasing factor «A», «B» and «D». Originality. Multi-level shear box test, developed by the author, is certified unequivocally adequate for determining inner shear resistance of reinforced and unreinforced granular materials, e.g. railway ballast

  15. Formation of periodic and localized patterns in an oscillating granular layer.

    Aranson, I.; Tsimring, L. S.; Materials Science Division; Bar Ilan Univ.; Univ. of California at San Diego

    1998-02-01

    A simple phenomenological model for pattern formation in a vertically vibrated layer of granular particles is proposed. This model exhibits a variety of stable cellular patterns including standing rolls and squares as well as localized excitations (oscillons and worms), similar to recent experimental observations (Umbanhowar et al., 1996). The model is an order parameter equation for the parametrically excited waves coupled to the mass conservation law. The structure and dynamics of the solutions resemble closely the properties of patterns observed in the experiments.

  16. The cerebellar Golgi cell and spatiotemporal organization of granular layer activity

    Egidio eD‘Angelo

    2013-05-01

    Full Text Available The cerebellar granular layer has been suggested to perform a complex spatiotemporal reconfiguration of incoming mossy fiber signals. Central to this role is the inhibitory action exerted by Golgi cells over granule cells: Golgi cells inhibit granule cells through double feedforward and feedback inhibitory loops and generate a broad lateral inhibition that extends beyond the afferent synaptic field. This characteristic connectivity has recently been investigated in great detail and been correlated with specific functional properties of the neuron. These include theta-frequency pacemaking, network entrainment into coherent oscillations and phase resetting. Important advances have also been made in terms of determining the membrane and synaptic properties of the neuron, and clarifying the mechanisms of activation by input bursts. Moreover, voltage sensitive dye imaging and multi-electrode array recordings, combined with mathematical simulations based on realistic computational models, have improved our understanding of the impact of Golgi cell activity on granular layer circuit computations. These investigations have highlighted the critical role of Golgi cells in: generating dense clusters of granule cell activity organized in center-surround structures, implementing combinatorial operations on multiple mossy fiber inputs, regulating transmission gain and cut-off frequency, controlling spike timing and burst transmission, and determining the sign, intensity and extension of long-term synaptic plasticity at the mossy fiber-granule cell relay. This review considers recent advances in the field, highlighting the functional implications of Golgi cells for granular layer network computation and indicating new challenges for cerebellar research.

  17. Preparation and recording characteristics of granular-type perpendicular magnetic recording media with thin intermediate layer

    Shintaku, K.; Kiya, T.

    2008-01-01

    Granular-type media with thin Ru intermediate layer were prepared on a highly oriented high-B s FeCo soft underlayer (SUL). A CoPt-TiO 2 recording layer on a Ru intermediate layer of only 2 nm had high-crystal orientation, high H c of 6.5 kOe, and a high squareness ratio (SQ) of 0.99. The magnetic property of the SUL was also good. The recording performance was measured for the media with different Ru intermediate thicknesses by using a single-pole-type (SPT) head. The media had large reproduced output even for the Ru intermediate layer thickness of 2 nm

  18. Preparation and recording characteristics of granular-type perpendicular magnetic recording media with thin intermediate layer

    Shintaku, K. [Akita Research Institute of Advanced Technology, Akita Prefectural R and D Center, 4-21 Sanuki, Araya, Akita 010-1623 (Japan)], E-mail: shintaku@ait.pref.akita.jp; Kiya, T. [Akita Research Institute of Advanced Technology, Akita Prefectural R and D Center, 4-21 Sanuki, Araya, Akita 010-1623 (Japan)

    2008-11-15

    Granular-type media with thin Ru intermediate layer were prepared on a highly oriented high-B{sub s} FeCo soft underlayer (SUL). A CoPt-TiO{sub 2} recording layer on a Ru intermediate layer of only 2 nm had high-crystal orientation, high H{sub c} of 6.5 kOe, and a high squareness ratio (SQ) of 0.99. The magnetic property of the SUL was also good. The recording performance was measured for the media with different Ru intermediate thicknesses by using a single-pole-type (SPT) head. The media had large reproduced output even for the Ru intermediate layer thickness of 2 nm.

  19. Pyramid-like basket cells in the granular layer of the dentate gyrus in the rat.

    Seress, L

    1978-01-01

    Basket cells of the dentate gyrus were identified using Nissl (cresyl violet) staining. It has been found that the ratio between basket and granule cells is 1:150--210. Only a few glial cells, mainly astroglia, were found in the granular layer of the dentate gyrus. In accordance with earlier data it was found that the granule cells and glial cells originate mainly postnatally, but the basket cells, like the pyramidal cells of the hippocampus, originate prenatally. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:701192

  20. Ge clusters and wetting layers forming from granular films on the Si(001) surface

    Storozhevykh, M S; Arapkina, L V; Yuryev, V A

    2016-01-01

    The report studies the transformation of a Ge granular film deposited on the Si(001) surface at room temperature into a Ge/Si(001) heterostructure as a result of rapid heating and annealing at 600 °C. As a result of the short-term annealing at 600 °C in conditions of a closed system, the Ge granular film transforms into a usual wetting layer and Ge clusters with multimodal size distribution and Ge oval drops having the highest number density. After the long-term thermal treatment of the Ge film at the same temperature, Ge drops disappear; the large clusters increase their sizes at the expense of the smaller ones. The total density of Ge clusters on the surface drastically decreases. The wetting layer mixed c(4 x 2) + p(2 x 2) reconstruction transforms into a single c(4 x 2) one which is likely to be thermodynamically favoured. Pyramids or domes are not observed on the surface after any annealing. (paper)

  1. Experimental analysis of embryogenesis of cerebellum in rat. II. Morphogenetic malformations following x-ray irradiation on day 18 of gestation

    Das, G.D.

    1977-01-01

    Rat embryos of 18 days gestation were exposed in utero to 170 R of x-ray irradiation. Embryos were collected six hours, 1, 2, and 3 days after irradiation, and animals of 2-, 6-, 15- and 30-day-old postnatal age were sacrificed. Six hours after irradiation pyknosis of cells was noticed in the external granular layer along the posterior aspect of the cerebellum. Neuroblasts, destined to differentiate into Purkinje cells, were found arrested in their migratory path. During subsequent periods of embryogenesis the external granular layer was found recovered, and clustering of the neuroblasts were disorganized and fragmented. This abnormal clustering of neuroblasts was permanent, and the external granular layer followed the same abnormal pattern in its growth. During postnatal development the internal granular layer also was found to follow the abnormal pattern of Purkinje cell layer. Those abnormal developmental events were seen to lead to malformed folia in the anterior regions of the cerebellum. In addition to it the cerebellum of x-ray irradiated animals appeared smaller than the normal. Issues having a bearing on the differential radiosensitivity of different cells, factors determining the small size of the cerebellum, and cellular events determining the morphogenetic malformations are discussed

  2. Cerebellum developmental challenges: From morphology to molecular issues

    Andrei Cosma

    2017-06-01

    Full Text Available Introduction: It is known that, throughout the development of the nervous system, the cellular migratory routes are an important part of its expansion; therefore, the cerebellum is ‘sprinkled’ with cellular changes during its growth. The aim of this study was to analyse the morphological features of the cerebellum cells in all the layers, during its development. Material and methods: We examined 14 cases of human cerebellum, ranging between 1 to 12 months by histopathology and immunohistochemistry. Results: Haematoxylin and eosin staining method confirmed the age-linked migration of the cells from the external granular layer into the internal granular layer. Moreover, immunohistochemical evaluation using PROX1 and NFAP showed positivity for the Purkinje cells. However, these cells exposed negativity on NSE stained specimens. On the other hand, the transience of the EGL was analyzed using OCT3/4, which showed the migration of the EGL cells through the molecular layer to the IGL. Also, GFAP and NFAP proved to be a useful tool for the identification of the climbing fibres and the variation of their density connected the age of the patient. Conclusions: The human cerebellum undergoes different morphological and molecular changes throughout its evolution during embryogenesis. The markers used in our study have proved to present a differential, stage-dependant reactivity and appeared as useful tools for the identification of different cerebellar structures. Our study is a challenging attempt to understand the basics of cerebellar development at a morphological and molecular level and may bring new perspectives for a better approach of cerebellar associated pathologies.

  3. CEREBELLUM DEVELOPMENTAL CHALLENGES: FROM MORPHOLOGY TO MOLECULAR ISSUES

    Andrei Cosma ¹

    2017-10-01

    Full Text Available INTRODUCTION: It is known that, throughout the development of the nervous system, the cellular migratory routes are an important part of its expansion; therefore, the cerebellum is ‘sprinkled’ with cellular changes during its growth. The aim of this study was to analyse the morphological features of the cerebellum cells in all the layers, during its development. MATERIAL AND METHODS: We examined 14 cases of human cerebellum, ranging between 1 month to 12 years by histopathology and immunohistochemistry. RESULTS: Haematoxylin and eosin staining method confirmed the age-linked migration of the cells from the external granular layer into the internal granular layer. Moreover, immunohistochemical evaluation using PROX1 and NFAP showed positivity for the Purkinje cells. However, these cells exposed negativity on NSE stained specimens. On the other hand, the transience of the EGL was analysed using OCT3/4, which showed the migration of the EGL cells through the molecular layer to the IGL. Also, GFAP and NFAP proved to be a useful tool for the identification of the climbing fibres and the variation of their density connected the age of the patient. CONCLUSIONS: The human cerebellum undergoes different morphological and molecular changes throughout its evolution during embryogenesis. The markers used in our study have proved to present a differential, stage-dependant reactivity and appeared as useful tools for the identification of different cerebellar structures. Our study is a challenging attempt to understand the basics of cerebellar development at a morphological and molecular level and may bring new perspectives for a better approach of cerebellar associated pathologies.

  4. Developmental Anatomy of Cerebellum of Long-Tailed Macaque (Macaca fascicularis at the First Trimester of Gestation

    Tri Wahyu Pangestiningsih

    2014-11-01

    Full Text Available Long tailed macaque was one of animal models in biomedical research because it has  many similarities with humans, both anatomical and physiological properties. There were many research about cerebellum associated with its role in the coordination of muscle activity. Understanding of normal development of cerebellum long tailed macaque may help to understand about the development in human cerebellum and its abnormalities. Embryonic and fetal brain samples were obtained through caesarean section and were  then made for histological preparation stained with cresyl violet. Staining results were observed using a microscope with a digital camera. Images obtained are processed by graphics software Adobe Photoshop CS 8.0. Cerebellum Macaca fascicularis Ed40 showed the isthmus and rhombic lip that were composed of ventricular layer, mantle layer, and marginal layer. Cerebellum Macaca fascicularis Fd55 showed future lobes and future  fissures, but the cortex and medulla are not bounded clear. The cortex consisted of the external granular layer, neuroblast basket, and neuroblast stellate, while the  medulla consisted of neuroblast deep cerebellar nuclei. From this research, we concluded that neurons were on stage of proliferation and migration in the embryo aged 40 days, then differentiated and migrated to form cortex  cerebellum and deep cerebellar nuclei at the age of 55 days, but the development of the cerebellum was not fully completed yet.

  5. Granular flows on erodible layers: type and evolution of flow and deposit structures

    Crosta, G.; De Blasio, F.; De Caro, M.; Volpi, G.; Frattini, P.

    2012-04-01

    The interaction of a fast moving landslide mass with the basal layer over which movement takes place has been discussed in previous contributions. Nevertheless, the evolution of the structures within the moving mass and the erodible layer are still to be described in detail (Hungr and Evans, 2004; Crosta et al., 1992, 2006, 2009, 2011; Dufresne et al., 2010; Mangeney et al., 2010) and modeling results (Crosta et al., 2006, 2009, 2011; Mangeney et al., 2010). We present some of the results from a campaign of laboratory experiments aimed at studying the evolution of a granular flow at the impact with and during the successive spreading over a cohesionless erodible layer. We performed these test to study the processes and to collect data and evidences to compare them with the results of numerical simulations and to verify capabilities of numerical codes. The laboratory setup consists of an inclined slope and an horizontal sector where release and transport, and deposition take place, respectively. Materials used for the tests are: a uniform rounded siliceous sand (Hostun sand; 0.125-0.5 mm) commonly adopted in lab tests because free of scale effects, and a gravel made of angular elements (12 mm in ave. size). Both the materials have been tested in dry conditions. Different slope angles have been tested (40, 45, 50, 55, 50, 66°) as well as different thicknesses of the erodible layer (0, 0.5, 1, 2 cm) and volumes of the released material (1.5, 3, 5, 9.6 liters). Tests have been monitored by means of a high speed camera and the pre- and post-failure geometries have been surveyed by means of a laser scanner. Deposit description allowed also the computation of volumes and the characterization of the different structures developed and frozen into the deposit. Experiments allowed us to observe the extreme processes occurring during the movement and the mise en place of the deposits. In particular, we observe the formation of a clear wave-like feature developing during the

  6. Locating the origin of stick slip instabilities in sheared granular layers

    Korkolis, Evangelos; Niemeijer, André

    2017-04-01

    Acoustic emission (AE) monitoring is a non-invasive technique widely used to evaluate the state of materials and structures. We have developed a system that can locate the source of AE events associated with unstable sliding (stick-slip) of sheared granular layers during laboratory friction experiments. Our aim is to map the spatial distribution of energy release due to permanent microstructural changes, using AE source locations as proxies. This will allow us to determine the distribution of applied work in a granular medium, which will be useful in developing constitutive laws that describe the frictional behavior of such materials. The AE monitoring system is installed on a rotary shear apparatus. This type of apparatus is used to investigate the micromechanical processes responsible for the macroscopic frictional behavior of granular materials at large shear displacements. Two arrays of 8 piezoelectric sensors each are installed into the ring-shaped steel pistons that confine our samples. The sensors are connected to a high-speed, multichannel oscilloscope that can record full waveforms. The apparatus is also equipped with a system that continuously records normal and lateral (shear) loads and displacements, as well as pore fluid pressure. Thus, we can calculate the frictional and volumetric response of our granular aggregates, as well as the location of AE sources. Here, we report on the results of room temperature experiments on granular aggregates consisting of glass beads or segregated mixtures of glass beads and calcite, at up to 5 MPa normal stress and sliding velocities between 1 and 100 μm/s. Under these conditions, glass beads exhibit unstable sliding behavior accompanied by significant AE activity, whereas calcite exhibits stable sliding and produces no AEs. We recorded a range of unstable sliding behaviors, from fast, regular stick slip at high normal stress (> 4 MPa) and sliding velocities below 20 μm/s, to irregular stick slip at low normal

  7. Stimulus-dependent state transition between synchronized oscillation and randomly repetitive burst in a model cerebellar granular layer.

    Takeru Honda

    2011-07-01

    Full Text Available Information processing of the cerebellar granular layer composed of granule and Golgi cells is regarded as an important first step toward the cerebellar computation. Our previous theoretical studies have shown that granule cells can exhibit random alternation between burst and silent modes, which provides a basis of population representation of the passage-of-time (POT from the onset of external input stimuli. On the other hand, another computational study has reported that granule cells can exhibit synchronized oscillation of activity, as consistent with observed oscillation in local field potential recorded from the granular layer while animals keep still. Here we have a question of whether an identical network model can explain these distinct dynamics. In the present study, we carried out computer simulations based on a spiking network model of the granular layer varying two parameters: the strength of a current injected to granule cells and the concentration of Mg²⁺ which controls the conductance of NMDA channels assumed on the Golgi cell dendrites. The simulations showed that cells in the granular layer can switch activity states between synchronized oscillation and random burst-silent alternation depending on the two parameters. For higher Mg²⁺ concentration and a weaker injected current, granule and Golgi cells elicited spikes synchronously (synchronized oscillation state. In contrast, for lower Mg²⁺ concentration and a stronger injected current, those cells showed the random burst-silent alternation (POT-representing state. It is suggested that NMDA channels on the Golgi cell dendrites play an important role for determining how the granular layer works in response to external input.

  8. Granular and layered ferroelectric–ferromagnetic thin-film nanocomposites as promising materials with high magnetotransmission effect

    Akbashev, A.R. [Department of Materials Science, Moscow State University, 119992 Moscow (Russian Federation); Telegin, A.V., E-mail: telegin@imp.uran.ru [M.N. Miheev Institute of Metal Physics of Ural Branch of RAS, 620990 Ekaterinburg (Russian Federation); Kaul, A.R. [Department of Chemistry, Moscow State University, 119992 Moscow (Russian Federation); Sukhorukov, Yu.P. [M.N. Miheev Institute of Metal Physics of Ural Branch of RAS, 620990 Ekaterinburg (Russian Federation)

    2015-06-15

    Epitaxial thin films of granular and layered nanocomposites consisting of ferromagnetic perovskite Pr{sub 1–x}Sr{sub x}MnO{sub 3} and ferroelectric hexagonal LuMnO{sub 3} were grown on ZrO{sub 2}(Y{sub 2}O{sub 3}) substrates using metal-organic chemical vapor deposition (MOCVD). A self-organized growth of the granular composite took place in situ as a result of phase separation of the Pr–Sr–Lu–Mn–O system into the perovskite and hexagonal phases. Optical transmission measurements revealed a large negative magnetotransmission effect in the layered nanocomposite over a wide spectral and temperature range. The granular nanocomposite unexpectedly showed an even larger, but positive, magnetotransmission effect at room temperature. - Highlights: • Thin-film ferromagnetic–ferroelectric nanocomposites have been prepared by MOCVD. • Giant change of optical transparency of nanocomposites in magnetic field was detected. • Positive magnetotransmission in the granular nanocomposite was discovered in the IR. • Negative magnetotransmission in the layered nanocomposite was revealed in the IR. • Ferroelectric–ferromangetic nanocomposite is a promising material for optoelectronics.

  9. Granular and layered ferroelectric–ferromagnetic thin-film nanocomposites as promising materials with high magnetotransmission effect

    Akbashev, A.R.; Telegin, A.V.; Kaul, A.R.; Sukhorukov, Yu.P.

    2015-01-01

    Epitaxial thin films of granular and layered nanocomposites consisting of ferromagnetic perovskite Pr 1–x Sr x MnO 3 and ferroelectric hexagonal LuMnO 3 were grown on ZrO 2 (Y 2 O 3 ) substrates using metal-organic chemical vapor deposition (MOCVD). A self-organized growth of the granular composite took place in situ as a result of phase separation of the Pr–Sr–Lu–Mn–O system into the perovskite and hexagonal phases. Optical transmission measurements revealed a large negative magnetotransmission effect in the layered nanocomposite over a wide spectral and temperature range. The granular nanocomposite unexpectedly showed an even larger, but positive, magnetotransmission effect at room temperature. - Highlights: • Thin-film ferromagnetic–ferroelectric nanocomposites have been prepared by MOCVD. • Giant change of optical transparency of nanocomposites in magnetic field was detected. • Positive magnetotransmission in the granular nanocomposite was discovered in the IR. • Negative magnetotransmission in the layered nanocomposite was revealed in the IR. • Ferroelectric–ferromangetic nanocomposite is a promising material for optoelectronics

  10. Effect of x irradiation on the biochemical maturation of rat cerebellum: postnatal cell formation

    Patel, A.J.; Balazs, R.; Altman, J.; Anderson, W.J.

    1975-01-01

    Rat cerebellum was irradiated with 100 R daily doses from birth to 10 days of age, and the animals were studied during the next 13 days. The growth of the body and of the forebrain were little affected, but that of the cerebellum was severely retarded. This was primarily due to a depression in new cell acquisition which during the irradiation period was only about 10 percent of that in the controls. On the other hand, it seems that the development of cells formed prior to irradiation was little affected; at day 10, the average size and the RNA and protein contents of the cells were significantly higher than at birth and they were more than double the values observed in the control. However, cell formation was not irreversibly affected: in the fortnight after the termination of irradiation the rise in cell numbers was more than 80 percent of that occurring in the control rats. A relatively normal development of the cerebellar cortex was indicated by the finding that the molecular and the internal granular layers increased substantially in size during the postirradiation period. Further, by 23 days of age the external granular layer, which is a main germinal site in the cerebellum disappeared, as in controls, and the concentration of DNA (packing density of cells) and the cellular contents of RNA and protein were normal. However, restitution was not complete: at 23 days of age, in comparison with controls, the weight of the cerebellum was 60 percent and the reduction in the total number of cells (-40 percent) was similar to the reduction in size of the internal granular layer, which contains the highest concentration of nerve cells in the cerebellum. (U.S.)

  11. Double-layered perpendicular magnetic recording media of granular-type FePt-MgO films

    Zhang Zhengang; Singh, Amarendra K.; Yin Jinhua; Perumal, A.; Suzuki, Takao

    2005-01-01

    The recording performance of double-layered granular-type FePt-MgO perpendicular magnetic recording media fabricated onto glass discs by sputtering is investigated. The (0 0 1)-textured FePt granular films are obtained by annealing FePt/MgO multilayers. Three different multilayer structures are compared in their magnetic properties and recording SNR performances. To evaluate thermal stability property of these granular-type FePt disks, the time-dependent magnetic force microscope (MFM) signal from the written bits on one of these disks is recorded in the temperature range 25-200 degree sign C. The signal decay at high observation temperature is interpreted based on the temperature dependence of magnetic anisotropy (K u )

  12. Movement of beta-irradiated epidermal basal cells to the spinous-granular layers in the absence of cell division

    Etoh, H.; Taguchi, Y.H.; Tabachnick, J.

    1975-01-01

    Guinea-pig epidermis was irradiated with 3000 rad of beta rays 1 hr after two injections of [ 3 H]thymidine 5 hr apart (labeled cells in S phase and G 2 phase) or 18 hr after injection (labeled early G 1 cells). In nonirradiated epidermis labeled basal cells divided within 24 hr with daughter cells remaining in the basal layer, and approximately 50 percent of the labeled cells moved into the spinal layer by the 3rd day. Cell division in nonirradiated epidermis diluted the number of silver grains/nucleus, and lightly labeled cells were found in the granular layer by day 7. Beta irradiation inhibited cell division but it did not slow the rate of transit (ca 8 days) of irradiated labeled cells from basal to granular layer, some of these remaining heavily labeled. Although cell division may play some role in upward movement of basal cells in normal epidermis detachment of a basal cell from the basement membrane and its transit to the granular layer is unimpaired in the absence of cell division. These findings suggest that some radioresistant metabolic function(s), not cell division, is responsible for upward movement of basal cells. (auth)

  13. Study of the damage induced by radiations with different linear energy transfer in the nerve cells of the rat cerebellum

    Krasavin, E.A.; Mashinskaya, T.E.; Ryzhov, N.I.

    1978-01-01

    The increase in space flight duration suggests the study of damage induced by high-fluxes of ionizing radiations in the tissues of the nervous system of the man. The quantitative and qualitative changes in the cerebellar granular cells of the rats of early postnatal period, affected by 25 and 50 MeV protons, 180 kV X-rays and Co 60 gamma-rays have been studied. It has been found that the radiosensitivity of neurons in different compartments of the cerebellar cortex varies significantly. Radiosensitivity of the inner and outer granular layers of the cerebellum to irradiation with 25 MeV protons was similar

  14. High-pass filtering and dynamic gain regulation enhance vertical bursts transmission along the mossy fiber pathway of cerebellum

    Jonathan Mapelli

    2010-05-01

    Full Text Available Signal elaboration in the cerebellum mossy fiber input pathway presents controversial aspects, especially concerning gain regulation and the spot-like (rather than beam-like appearance of granular-to-molecular layer transmission. By using voltage-sensitive dye (VSD imaging in rat cerebellar slices (Mapelli et al., 2010, we found that mossy fiber bursts optimally excited the granular layer above ~50 Hz and the overlaying molecular layer above ~100 Hz, thus generating a cascade of high-pass filters. NMDA receptors enhanced transmission in the granular, while GABA-A receptors depressed transmission in both the granular and molecular layer. Burst transmission gain was controlled through a dynamic frequency-dependent involvement of these receptors. Moreover, while high-frequency transmission was enhanced along vertical lines connecting the granular to molecular layer, no high-frequency enhancement was observed along the parallel fiber axis in the molecular layer. This was probably due to the stronger effect of Purkinje cell GABA-A receptor-mediated inhibition occurring along the parallel fibers than along the granule cell axon ascending branch. The consequent amplification of burst responses along vertical transmission lines could explain the spot-like activation of Purkinje cells observed following punctuate stimulation in vivo .

  15. Transcriptome differentiation along the dorso-ventral axis in laser-captured microdissected rat hippocampal granular cell layer

    Christensen, T.; Bisgaard, C.F.; Nielsen, Henrik Bjørn

    2010-01-01

    Several findings suggest a functional and anatomical differentiation along the dorso-ventral axis of the hippocampus. Lesion studies in rats have indicated that the dorsal hippocampus preferentially plays a role in spatial learning and memory, while the ventral hippocampus is involved in anxiety...... and ventral granular cell layer with a false discovery rate below 5% and with a relative change in gene expression level of 20% or more. From this pool of genes 45 genes were more than two-fold regulated, 13 genes being dorsally enriched and 32 genes being ventrally enriched. Moreover, cluster analysis based...

  16. Stability of stones in the top layer of a granular filter : Literature survey

    Hofland, B.

    2000-01-01

    In order to understand the processes involved in damaging a granular filter, the behaviour of the separate particles it is made of must be known. The hydrodynamic forces on the particles are very important for understanding this behaviour. These forces have been examined by many researchers. Chapter

  17. The effect of capped layer thickness on switching behavior in perpendicular CoCrPt based coupled granular/continuous media

    Li, W.M.; Lim, W.K.; Shi, J.Z.; Ding, J.

    2013-01-01

    A systematic investigation of magnetic switching behavior of CoCrPt based capped media (perpendicularly coupled granular/continuous (CGC) media consisting of granular CoCrPt:SiO 2 TiO 2 Ta 2 O 5 /capped CoCrPt(B)) is performed by varying the thickness of the capped layer from 0 to 9 nm. The microscopic structures of CGC media with different thickness of capped layer are examined by transmission electron microscope. We find out that CoCrPt magnetic grains are separated by nonmagnetic oxide grain boundaries. Grain size and grain boundary are about 8.9 nm and 2 nm, respectively. The nonmagnetic oxide grain boundaries in the granular layer do not disappear immediately at the interface between the granular and capped layers. The amorphous grain boundary phase in the granular layer propagates to the top surface of the capped layer. After capping with the CoCrPt(B) layer, the grain size at the surface of CGC structure increases and the grain boundary decreases. Both coercivity and intergranular exchange coupling of the CGC media are investigated by Polar magneto-optic Kerr effect magnetometer and alternating gradient force magnetometer. Although H c apparently decreases at thicker capped layer, no obvious variation of macroscopic switching field distribution (SFD/H c ) is observed. We separate intrinsic switching field distribution from intergranular interactions. The investigation of reduced intrinsic SFD/H c and increased hysteresis loop slope at coercivity, suggests that improvement of absolute switching field distribution (SFD) is caused by both strong intergranular exchange coupling and uniform grain size. Micromagnetic simulation results further verify our conclusion that the capped layer in CGC media is not uniformly continuous but has some granular nature. However, grains in the CoCrPt(B) capped layer is not absolutely isolated, strong exchange coupling exists between grains. - Highlights: • In CGC media, CoCrPt magnetic grains are separated by nonmagnetic oxide

  18. AβPP/PS1 Transgenic Mice Show Sex Differences in the Cerebellum Associated with Aging.

    Ordoñez-Gutierrez, Lara; Fernandez-Perez, Ivan; Herrera, Jose Luis; Anton, Marta; Benito-Cuesta, Irene; Wandosell, Francisco

    2016-09-06

    Cerebellar pathology has been related to presenilin 1 mutations in certain pedigrees of familial Alzheimer's disease. However, cerebellum tissue has not been intensively analyzed in transgenic models of mutant presenilins. Furthermore, the effect of the sex of the mice was not systematically analyzed, despite the fact that important gender differences in the evolution of the disease in the human population have been described. We analyzed whether the progression of amyloidosis in a double transgenic mouse, AβPP/PS1, is susceptible to aging and differentially affects males and females. The accumulation of amyloid in the cerebellum differentially affects males and females of the AβPP/PS1 transgenic line, which was found to be ten-fold higher in 15-month-old females. Amyloid-β accumulation was more evident in the molecular layer of the cerebellum, but glia reaction was only observed in the granular layer of the older mice. The sex divergence was also observed in other neuronal, survival, and autophagic markers. The cerebellum plays an important role in the evolution of the pathology in this transgenic mouse model. Sex differences could be crucial for a complete understanding of this disease. We propose that the human population could be studied in this way. Sex-specific treatment strategies in human populations could show a differential response to the therapeutic approach.

  19. Quantification of cell death in developing cerebellum by a 14C tracer method

    Griffin, W.S.; Woodward, D.J.; Chanda, R.

    1978-01-01

    To study the question of whether or not cell death contributes significantly to normal or stressed postnatal brain development in a way which is biochemically quantifiable, we carried out an experiment to assess the amount of cell death in developing cerebellum. By measuring the loss of DNA content and the loss of 14 C from labelled thymidine previously incorporated into the DNA fraction (DNAF) in X-irradiated neonatal animals, shown by histological methods to have cell death to the degree of degranulating the external granular layer (EGL), we showed that when cells die both label and DNA content are greatly decreased in the cerebellum. Experiments on both normal and malnourished animals showed that cell death does not contribute significantly to cerebellar development in either malnutrition-stressed or normal animals. Here, we present a biochemical tool for assessing cell death and evidence that cell death does not contribute significantly to cerebellar development

  20. Cerebellum - function (image)

    The cerebellum processes input from other areas of the brain, spinal cord and sensory receptors to provide precise timing ... the skeletal muscular system. A stroke affecting the cerebellum may cause dizziness, nausea, balance and coordination problems.

  1. Effects of a whole body gamma irradiation on GABA repartition in infant rats cerebellum and hippocampal formation

    Menetrier, F.; Vernois, Y.; Court, L.

    1992-01-01

    'Full-Text:' Thirteen-day-old rats were exposed to a single dose of 4 or 0,5 Gy of gamma at a dose rate of 0,25 Gy/min and were killed about 5h after. Fixation was achieved in situ using glutaraldehyde. For GABA immunocytochemistry transversal sections were incubated with antiserum against GABA, then with PAP and revealed with diaminobenzidine. Proliferative layers are still observed in the infant rat cerebellum (external granular layer) and hippocampal formation (subgranular layer of the dentate gyrus). When irradiation occurs a high percent of these two layers cells are pycnotic. In the normal cerebellum, no immunostaining is observed in external granular layer cell bodies. The only labelled structures are few cytoplasmic expansions coming from subjacent layers. When irradiated, a strong GABA staining appears around pycnotic cells as a network with labelled meshes. GABA staining and pycnotic cells were more especially important when the irradiation increases. Further studies are needed to specify the nature of labelled meshes. In the normal hippocampal formation, subgranular cells are not GABA stained. Staining occurs in cells which are not granule cells. They are scattered throughout cell layers of the dentate gyrus with predominance in the hilus. After irradiation, GABA repartition is not modified. After a 4 Gy whole body gamma irradiation, the inhibitory GABA system is not injured. Other amino-acid neurotransmitters such as Glutamate could be modified. (author)

  2. Microtubule-Associated Proteins in Mesial Temporal Lobe Epilepsy with and without Psychiatric Comorbidities and Their Relation with Granular Cell Layer Dispersion

    Ludmyla Kandratavicius

    2013-01-01

    Full Text Available Background. Despite strong association between epilepsy and psychiatric comorbidities, biological substrates are unknown. We have previously reported decreased mossy fiber sprouting in mesial temporal lobe epilepsy (MTLE patients with psychosis and increased in those with major depression. Microtubule associated proteins (MAPs are essentially involved in dendritic and synaptic sprouting. Methods. MTLE hippocampi of subjects without psychiatric history, MTLE + major depression, and MTLE + interictal psychosis derived from epilepsy surgery and control necropsies were investigated for neuronal density, granular layer dispersion, and MAP2 and tau immunohistochemistry. Results. Altered MAP2 and tau expression in MTLE and decreased tau expression in MTLE with psychosis were found. Granular layer dispersion correlated inversely with verbal memory scores, and with MAP2 and tau expression in the entorhinal cortex. Patients taking fluoxetine showed increased neuronal density in the granular layer and those taking haloperidol decreased neuronal density in CA3 and subiculum. Conclusions. Our results indicate relations between MAPs, granular layer dispersion, and memory that have not been previously investigated. Differential MAPs expression in human MTLE hippocampi with and without psychiatric comorbidities suggests that psychopathological states in MTLE rely on differential morphological and possibly neurochemical backgrounds. This clinical study was approved by our institution’s Research Ethics Board (HC-FMRP no. 1270/2008 and is registered under the Brazilian National System of Information on Ethics in Human Research (SISNEP no. 0423.0.004.000-07.

  3. Highly (002) textured large grain bcc Cr{sub 80}Mn{sub 20} seed layer on Cr{sub 50}Ti{sub 50} amorphous layer for FePt-C granular film

    Jeon, Seong-Jae, E-mail: jsjigst@ecei.tohoku.ac.jp; Saito, Shin [Department of Electronic Engineering, Tohoku University, 6-6-05 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Hinata, Shintaro [Department of Electronic Engineering, Tohoku University, 6-6-05 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Japan Society for the Promotion of Science Research Fellow (PD), 5-3-1, Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Takahashi, Migaku [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2015-05-07

    Effect of bcc Cr{sub 80}Mn{sub 20} seed layer and Cr{sub 50}Ti{sub 50} amorphous texture inducing layer on the heteroepitaxy system in FePt-C granular film was studied by introducing a new concept of the layered structure. The concept suggested that the large grain seed layer in which the crystallographic texture was initially formed on an amorphous layer in the layered structure can reduce the angular distribution of (002) c-axis crystal orientation in the FePt-C granular film owing to heteroepitaxial growth. Structure analysis by X-ray diffraction revealed that (1) when the substrate heating temperature was elevated from 300 °C to 500 °C, grain size in the seed layer increased from 9.8 nm to 11.6 nm, and then decreased with further increasing the substrate temperature. The reduction of the grain size over 500 °C corresponds to the crystallization of the amorphous texture inducing layer, (2) when the grain size increased from 9.8 nm to 11.6 nm, the angular distribution of the (002) orientation in the seed layer dramatically decreased from 13.7° to 4.1°. It was shown that the large grain seed layer increased the perpendicular hysteresis in FePt-C granular film.

  4. Granular flow

    Mitarai, Namiko; Nakanishi, Hiizu

    2012-01-01

    Granular material is a collection of macroscopic particles that are visible with naked eyes. The non-equilibrium nature of the granular materials makes their rheology quite different from that of molecular systems. In this minireview, we present the unique features of granular materials focusing...... on the shear flow of dry granular materials and granule-liquid mixture....

  5. CEMS and XRD studies on changing shape of iron nano-particles by irradiation of Au ions of Fe-implanted Al2O3 granular layer

    Kato, T.; Wakabayashi, H.; Hashimoto, M.; Toriyama, T.; Taniguchi, S.; Hayashi, N.; Sakamoto, I.

    2007-01-01

    In order to observe an inverse Ostwald ripening of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers, 3 MeV Au ions were irradiated to Fe nano-particles in these layers with doses of 0.5x and 1.5x10 16 ions/cm 2 . It was found by Conversion Electron Mossbauer Spectroscopy (CEMS) that the inverse Ostwald ripening occurred by fractions of percentages and the magnetic anisotropy of Fe nano-particles was induced to the direction of Au ion beam, i.e. perpendicular to the granular plane. The average crystallite diameters of Fe nano-particles for Au ions unirradiated and irradiated samples were measured using Scherrer's formula from FWHM of Fe (110) X-ray Diffraction (XRD) patterns obtained by 2θ and 2θ/θ methods. It was confirmed that the average crystallite diameters of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers were extended by Au ions irradiation. (author)

  6. Reduction of intergranular exchange coupling and grain size for high Ku CoPt-based granular media: Metal-oxide buffer layer and multiple oxide boundary materials

    Kim Kong Tham

    2018-05-01

    Full Text Available Investigation of magnetic properties and microstructure of granular media with various multiple oxides as the grain boundary material is reported. Saturation magnetization (Ms, uniaxial magnetocrystalline anisotropy (Ku, and magnetic grain diameter (GD of the granular media show linear correlation with volume weighted average for melting point (Tm of each oxides (Tmave. Ku of magnetic grains (Kugrain shows a trade-off relation with GD that it is a big challenge to satisfy both high Kugrain and small GD by only controlling Tmave. To obtain a granular medium with appropriate Kugrain, GD, and low degree of intergranular exchange coupling, the combination of Tmave control of grain boundary material by mixing oxides and employment of a buffer layer are required. Here the degree of intergranular exchange coupling is estimated from the slope of M-H loop at around coercivity (α. By applying this technique, a typical granular medium with Kugrain of 1.0×107 erg/cm3, GD of 5.1 nm, and α of 1.2 is realized.

  7. Reduction of intergranular exchange coupling and grain size for high Ku CoPt-based granular media: Metal-oxide buffer layer and multiple oxide boundary materials

    Tham, Kim Kong; Kushibiki, Ryosuke; Kamada, Tomonari; Hinata, Shintaro; Saito, Shin

    2018-05-01

    Investigation of magnetic properties and microstructure of granular media with various multiple oxides as the grain boundary material is reported. Saturation magnetization (Ms), uniaxial magnetocrystalline anisotropy (Ku), and magnetic grain diameter (GD) of the granular media show linear correlation with volume weighted average for melting point (Tm) of each oxides (Tmave). Ku of magnetic grains (Kugrain) shows a trade-off relation with GD that it is a big challenge to satisfy both high Kugrain and small GD by only controlling Tmave. To obtain a granular medium with appropriate Kugrain, GD, and low degree of intergranular exchange coupling, the combination of Tmave control of grain boundary material by mixing oxides and employment of a buffer layer are required. Here the degree of intergranular exchange coupling is estimated from the slope of M-H loop at around coercivity (α). By applying this technique, a typical granular medium with Kugrain of 1.0×107 erg/cm3, GD of 5.1 nm, and α of 1.2 is realized.

  8. Cellular commitment in the developing cerebellum

    Marzban, Hassan; Del Bigio, Marc R.; Alizadeh, Javad; Ghavami, Saeid; Zachariah, Robby M.; Rastegar, Mojgan

    2014-01-01

    The mammalian cerebellum is located in the posterior cranial fossa and is critical for motor coordination and non-motor functions including cognitive and emotional processes. The anatomical structure of cerebellum is distinct with a three-layered cortex. During development, neurogenesis and fate decisions of cerebellar primordium cells are orchestrated through tightly controlled molecular events involving multiple genetic pathways. In this review, we will highlight the anatomical structure of human and mouse cerebellum, the cellular composition of developing cerebellum, and the underlying gene expression programs involved in cell fate commitments in the cerebellum. A critical evaluation of the cell death literature suggests that apoptosis occurs in ~5% of cerebellar cells, most shortly after mitosis. Apoptosis and cellular autophagy likely play significant roles in cerebellar development, we provide a comprehensive discussion of their role in cerebellar development and organization. We also address the possible function of unfolded protein response in regulation of cerebellar neurogenesis. We discuss recent advancements in understanding the epigenetic signature of cerebellar compartments and possible connections between DNA methylation, microRNAs and cerebellar neurodegeneration. Finally, we discuss genetic diseases associated with cerebellar dysfunction and their role in the aging cerebellum. PMID:25628535

  9. Cellular Commitment in the Developing Cerebellum

    Hassan eMarzban

    2015-01-01

    Full Text Available The mammalian cerebellum is located in the posterior cranial fossa and is critical for motor coordination and non-motor functions including cognitive and emotional processes. The anatomical structure of cerebellum is distinct with a three-layered cortex. During development, neurogenesis and fate decisions of cerebellar primordium cells are orchestrated through tightly controlled molecular events involving multiple genetic pathways. In this review, we will highlight the anatomical structure of human and mouse cerebellum, the cellular composition of developing cerebellum, and the underlying gene expression programs involved in cell fate commitments in the cerebellum. A critical evaluation of the cell death literature suggests that apoptosis occurs in ~5% of cerebellar cells, most shortly after mitosis. Apoptosis and cellular autophagy likely play significant roles in cerebellar development, we provide a comprehensive discussion of their role in cerebellar development and organization. We also address the possible function of unfolded protein response in regulation of cerebellar neurogenesis. We discuss recent advancements in understanding the epigenetic signature of cerebellar compartments and possible connections between DNA methylation, microRNAs and cerebellar neurodegeneration. Finally, we then discuss genetic diseases associated with cerebellar dysfunction and their role in the aging cerebellum.

  10. Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons.

    Alp, Murat; Cucinotta, Francis A

    2018-03-01

    Exposure to heavy-ion radiation during cancer treatment or space travel may cause cognitive detriments that have been associated with changes in neuron morphology and plasticity. Observations in mice of reduced neuronal dendritic complexity have revealed a dependence on radiation quality and absorbed dose, suggesting that microscopic energy deposition plays an important role. In this work we used morphological data for mouse dentate granular cell layer (GCL) neurons and a stochastic model of particle track structure and microscopic energy deposition (ED) to develop a predictive model of high-charge and energy (HZE) particle-induced morphological changes to the complex structures of dendritic arbors. We represented dendrites as cylindrical segments of varying diameter with unit aspect ratios, and developed a fast sampling method to consider the stochastic distribution of ED by δ rays (secondary electrons) around the path of heavy ions, to reduce computational times. We introduce probabilistic models with a small number of parameters to describe the induction of precursor lesions that precede dendritic snipping, denoted as snip sites. Predictions for oxygen ( 16 O, 600 MeV/n) and titanium ( 48 Ti, 600 MeV/n) particles with LET of 16.3 and 129 keV/μm, respectively, are considered. Morphometric parameters to quantify changes in neuron morphology are described, including reduction in total dendritic length, number of branch points and branch numbers. Sholl analysis is applied for single neurons to elucidate dose-dependent reductions in dendritic complexity. We predict important differences in measurements from imaging of tissues from brain slices with single neuron cell observations due to the role of neuron death through both soma apoptosis and excessive dendritic length reduction. To further elucidate the role of track structure, random segment excision (snips) models are introduced and a sensitivity study of the effects of the modes of neuron death in predictions

  11. Dose response relationship of disturbed migration of Purkinje cells in the cerebellum due to X-irradiation

    Darmanto, W.; Inouye, Minoru; Hayasaka, Shizu; Takagishi, Yoshiko; Aolad, H.; Murata, Yoshiharu

    1998-01-01

    Pregnant rats were exposed to 2.0, 2.25 or 2.5 Gy X-irradiation on gestation day 21. Pups were sacrificed 12 hr after exposure, and on postnatal day 5 (P5), P7 and P9. Their cerebella were observed immunohistochemically using anti-inositol 1,4,5 triphosphate (IP3) receptor antibody to identify Purkinje cells. These cells were disturbed to migrate and remained in the internal granular layer and white matter of the cerebellum. They had short dendrites, and some showed an abnormal direction of dendrites in rats exposed to 2.25 or 2.5 Gy. Alignment of Purkinje cells was also disturbed when examined either on P5, P7 or P9 especially by doses of 2.25 and 2.5 Gy. There was a relationship between X-ray doses and the number of cells piling up in the Purkinje cell layer of the cerebellum. The dose-response relationship with the number of ectopic Purkinje cells was noted in the anterior lobes of the cerebellum. (author)

  12. MicroRNAs Promote Granule Cell Expansion in the Cerebellum Through Gli2.

    Constantin, Lena; Wainwright, Brandon J

    2015-12-01

    MicroRNAs (miRNAs) are important regulators of cerebellar function and homeostasis. Their deregulation results in cerebellar neuronal degeneration and spinocerebellar ataxia type 1 and contributes to medulloblastoma. Canonical miRNA processing involves Dicer, which cleaves precursor miRNAs into mature double-stranded RNA duplexes. In order to address the role of miRNAs in cerebellar granule cell precursor development, loxP-flanked exons of Dicer1 were conditionally inactivated using the granule cell precursor-specific Atoh1-Cre recombinase. A reduction of 87% in Dicer1 transcript was achieved in this conditional Dicer knockdown model. Although knockdown resulted in normal survival, mice had disruptions to the cortical layering of the anterior cerebellum, which resulted from the premature differentiation of granule cell precursors in this region during neonatal development. This defect manifested as a thinner external granular layer with ectopic mature granule cells, and a depleted internal granular layer. We found that expression of the activator components of the Hedgehog-Patched pathway, the Gli family of transcription factors, was perturbed in conditional Dicer knockdown mice. We propose that loss of Gli2 mRNA mediated the anterior-restricted defect in conditional Dicer knockdown mice and, as proof of principle, were able to show that miR-106b positively regulated Gli2 mRNA expression. These findings confirm the importance of miRNAs as positive mediators of Hedgehog-Patched signalling during granule cell precursor development.

  13. X-ray-induced cell death by apoptosis in the immature rat cerebellum

    Harmon, B.V.; Allan, D.J.

    1988-01-01

    The cells of the external granular layer (EGL) of the developing cerebellum are known to be particularly sensitive to radiation. In the past, changes induced in this layer by irradiation have been referred to by non-specific terms such as pyknotic cells and the mode of cell death has been assumed to be necrosis. However, in published light micrographs of these dying cells, the appearance is suggestive of apoptosis, a distinctive mode of cell death which occurs spontaneously in normal adult and embryonic tissues and can also be triggered by certain pathological stimuli. This light and transmission electron microscopic study of control and irradiated (7 h post-irradiation) rat cerebellum from 18 day fetuses and 5 day-old neonates showed that the cell death was effected by apoptosis. The apoptosis was markedly enhanced by x-irradiation and quantification of the cell death in the EGL of 5 day-old rats exposed to 4, 8, 25, 100, and 400 cGy x-irradiation demonstrated that there was a positive dose response relationship. The extent of cell death by apoptosis which was 0.2% in control, ranged from 0.8% after 4 cGy to 62.3% after 400 cGy x-irradiation. The recognition that cell death by apoptosis can be a major component of x-irradiation damage has important implications for radiobiological studies

  14. Cerebellum and apraxia.

    Mariën, Peter; van Dun, Kim; Verhoeven, Jo

    2015-02-01

    As early as the beginning of the nineteenth century, a variety of nonmotor cognitive and affective impairments associated with cerebellar pathology were occasionally documented. A causal link between cerebellar disease and nonmotor cognitive and affective disorders has, however, been dismissed for almost two centuries. During the past decades, the prevailing view of the cerebellum as a mere coordinator of autonomic and somatic motor function has changed fundamentally. Substantial progress has been made in elucidating the neuroanatomical connections of the cerebellum with the supratentorial association cortices that subserve nonmotor cognition and affect. Furthermore, functional neuroimaging studies and neurophysiological and neuropsychological research have shown that the cerebellum is crucially involved in modulating cognitive and affective processes. This paper presents an overview of the clinical and neuroradiological evidence supporting the view that the cerebellum plays an intrinsic part in purposeful, skilled motor actions. Despite the increasing number of studies devoted to a further refinement of the typology and anatomoclinical configurations of apraxia related to cerebellar pathology, the exact underlying pathophysiological mechanisms of cerebellar involvement remain to be elucidated. As genuine planning, organization, and execution disorders of skilled motor actions not due to motor, sensory, or general intellectual failure, the apraxias following disruption of the cerebrocerebellar network may be hypothetically considered to form part of the executive cluster of the cerebellar cognitive affective syndrome (CCAS), a highly influential concept defined by Schmahmann and Sherman (Brain 121:561-579, 1998) on the basis of four symptom clusters grouping related neurocognitive and affective deficits (executive, visuospatial, affective, and linguistic impairments). However, since only a handful of studies have explored the possible role of the cerebellum in

  15. Granular patterns

    Aranson, Igor S

    2009-01-01

    This title presents a review of experiments and novel theoretical concepts needed to understand the mechanisms of pattern formation in granular materials. An effort is made to connect concepts and ideas developed in granular physics with new emergent fields, especially in biology, such as cytoskeleton dynamics.

  16. Theta-frequency resonance at the cerebellum input stage improves spike-timing on the millisecond time-scale

    Daniela eGandolfi

    2013-04-01

    Full Text Available The neuronal circuits of the brain are thought to use resonance and oscillations to improve communication over specific frequency bands (Llinas, 1988; Buzsaki, 2006. However, the properties and mechanism of these phenomena in brain circuits remain largely unknown. Here we show that, at the cerebellum input stage, the granular layer generates its maximum response at 5-7 Hz both in vivo following tactile sensory stimulation of the whisker pad and in acute slices following mossy fiber-bundle stimulation. The spatial analysis of granular layer activity performed using voltage-sensitive dye (VSD imaging revealed 5-7 Hz resonance covering large granular layer areas. In single granule cells, resonance appeared as a reorganization of output spike bursts on the millisecond time-scale, such that the first spike occurred earlier and with higher temporal precision and the probability of spike generation increased. Resonance was independent from circuit inhibition, as it persisted with little variation in the presence of the GABAA receptor blocker, gabazine. However, circuit inhibition reduced the resonance area more markedly at 7 Hz. Simulations with detailed computational models suggested that resonance depended on intrinsic granule cells ionic mechanisms: specifically, Kslow (M-like and KA currents acted as resonators and the persistent Na current and NMDA current acted as amplifiers. This form of resonance may play an important role for enhancing coherent spike emission from the granular layer when theta-frequency bursts are transmitted by the cerebral cortex and peripheral sensory structures during sensory-motor processing, cognition and learning.

  17. Immunohistochemical detection of autophagy-related microtubule-associated protein 1 light chain 3 (LC3) in the cerebellums of dogs naturally infected with canine distemper virus.

    Kabak, Y B; Sozmen, M; Yarim, M; Guvenc, T; Karayigit, M O; Gulbahar, M Y

    2015-01-01

    We investigated the expression of microtubule-associated protein 1 light chain 3 (LC3) protein in the cerebellums of dogs infected with canine distemper virus (CDV) using immunohistochemistry to detect autophagy. The cerebellums of 20 dogs infected with CDV were used. Specimens showing demyelination of white matter were considered to have an acute infection, whereas specimens showing signs of severe perivascular cuffing and demyelination of white matter were classified as having chronic CDV. Cerebellar sections were immunostained with CDV and LC3 antibodies. The cytoplasm of Purkinje cells, granular layer cells, motor neurons in large cerebellar ganglia and some neurons in white matter were positive for the LC3 antibody in both the control and CDV-infected dogs. In the infected cerebellums, however, white matter was immunostained more intensely, particularly the neurons and gemistocytic astrocytes in the demyelinated areas, compared to controls. Autophagy also was demonstrated in CDV-positive cells using double immunofluorescence staining. Our findings indicate that increased autophagy in the cerebellum of dogs naturally infected with CDV may play a role in transferring the virus from cell to cell.

  18. A comparison of effects between accelerated heavy ion irradiation and X-irradiation on the development of rat cerebellum

    Inouye, Minoru; Hayasaka, Shizu; Murata, Yoshiharu; Takahashi, Sentaro; Kubota, Yoshihisa

    1999-01-01

    The purpose of this experiment is to compare the effects of 290 MeV/u carbon-ion irradiation and X-irradiation on the development of rat cerebellum. Pregnant rats were exposed to carbon-ion beams at a single dose of 1.5 Gy on day 19.0 of gestation. Other groups of pregnant rats were exposed to X-rays on day 19.0 at single doses of 1.5, 2.0 and 2.5 Gy. Their fetuses were removed 8 hr after exposure, and an acute effect examined microscopically for cell death in the external granular layer of the cerebellum. Other dams were allowed to give birth and rear their litters. The offspring were sacrificed at 6 weeks of age, and their cerebella were examined for foliar malformation. The results showed that the effect of 1.5 Gy carbon-ion irradiation on the development of cerebellum was stronger than that of 1.5 Gy X-irradiation and similar to 2.0-2.5 Gy X-irradiation. (author)

  19. The volume of Purkinje cells decreases in the cerebellum of acrylamide-intoxicated rats, but no cells are lost

    Larsen, Jytte Overgaard; Tandrup, T; Braendgaard, H

    1994-01-01

    The effects of acrylamide intoxication on the numbers of granule and Purkinje cells and the volume of Purkinje cell perikarya have been evaluated with stereological methods. The analysis was carried out in the cerebella of rats that had received a dose of 33.3 mg/kg acrylamide, twice a week, for 7.......5 weeks. The total numbers of cerebellar granule and Purkinje cells were estimated using the optical fractionator and the mean volume of the Purkinje cell perikarya was estimated with the vertical rotator technique. The volumes of the molecular layer, the granular cell layer and the white matter were...... estimated using the Cavalieri principle. The mean weight of the cerebellum of the intoxicated rats was 7% lower than that of the control rats (2P = 0.001). The numbers of the Purkinje cells and granule cells were the same in both groups, but the mean volume of the perikarya of the Purkinje cells...

  20. Localizing genes to cerebellar layers by classifying ISH images.

    Lior Kirsch

    Full Text Available Gene expression controls how the brain develops and functions. Understanding control processes in the brain is particularly hard since they involve numerous types of neurons and glia, and very little is known about which genes are expressed in which cells and brain layers. Here we describe an approach to detect genes whose expression is primarily localized to a specific brain layer and apply it to the mouse cerebellum. We learn typical spatial patterns of expression from a few markers that are known to be localized to specific layers, and use these patterns to predict localization for new genes. We analyze images of in-situ hybridization (ISH experiments, which we represent using histograms of local binary patterns (LBP and train image classifiers and gene classifiers for four layers of the cerebellum: the Purkinje, granular, molecular and white matter layer. On held-out data, the layer classifiers achieve accuracy above 94% (AUC by representing each image at multiple scales and by combining multiple image scores into a single gene-level decision. When applied to the full mouse genome, the classifiers predict specific layer localization for hundreds of new genes in the Purkinje and granular layers. Many genes localized to the Purkinje layer are likely to be expressed in astrocytes, and many others are involved in lipid metabolism, possibly due to the unusual size of Purkinje cells.

  1. From cell extracts to fish schools to granular layers: the universal hydrodynamics of self-driven systems

    Ramaswamy, Sriram

    2007-03-01

    Collections of self-driven or ``active'' particles are now recognised as a distinct kind of nonequilibrium matter, and an understanding of their phases, hydrodynamics, mechanical response, and correlations is a vital and rapidly developing part of the statistical physics of soft-matter systems far from equilibrium. My talk will review our recent results, from theory, simulation and experiment, on order, fluctuations, and flow instabilities in collections of active particles, in suspension or on a solid surface. Our work, which began by adapting theories of flocking to include the hydrodynamics of the ambient fluid, provides the theoretical framework for understanding active matter in all its diversity: contractile filaments in cell extracts, crawling or dividing cells, collectively swimming bacteria, fish schools, and agitated monolayers of orientable granular particles.

  2. Spreading of a granular droplet

    Clement, Eric; Sanchez, Ivan; Raynaud, Franck; Lanuza, Jose; Andreotti, Bruno; Aranson, Igor

    2008-03-01

    The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the``granular droplet'') and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

  3. Impairment of DNA synthesis in Gunn rat cerebellum.

    Yamada, N; Sawasaki, Y; Nakajima, H

    1977-05-06

    Brain DNA synthesis was developmentally investigated in Gunn rat with marked cerebellar hypoplasia due to hereditary hyperbilirubinemia. In this mutant rat, the Purkinje cell was nearly selectively affected in the cerebellar cortex by bilirubin. The impaired DNA synthesis was observed in homozygous (jj) Gunn rat cerebellum, in which the DNA content and [3H]thymidine incorporation rate into DNA decreased after 10 days of age compared to those in the heterozygous (Jj)littermate. In contrast, these impairments were not found in the non-cerebellar parts of the brain and liver of jj Gunn rat. The activity of cerebellar thymidine kinase in jj Gunn rat decreased from a very early stae, being 80% of Jj rat at 6 days, and 50% at 10 days of age. The enzyme activity was not affected in the non-cerebellar parts of the brain. Although bilirubin competitively inhibited cerebellar thymidine kinase activity in vitro (15% at 10(-5) M), such bilirubin level was found to be about 1000-fold that in vivo. Moreover, photo-degradation of bilirubin in jj cerebellum exhibited no improvement in thymidine kinase activity, and the presence of an enzyme inactivator was not suggested in jj cerebellum. These results seem to indicate that the induction of thymidine kinase might be affected in jj Gunn rat cerebellum. The possibility that the impaired DNA synthesis in the external granular cells in jj cerebellum may be due to Purkinje cell damage is discussed.

  4. Neuropathologic features in the hippocampus and cerebellum of three older men with fragile X syndrome

    Greco Claudia M

    2011-02-01

    Full Text Available Abstract Background Fragile X syndrome (FXS is the most common inherited form of intellectual disability, and is the most common single-gene disorder known to be associated with autism. Despite recent advances in functional neuroimaging and our understanding of the molecular pathogenesis, only limited neuropathologic information on FXS is available. Methods Neuropathologic examinations were performed on post-mortem brain tissue from three older men (aged 57, 64 and 78 years who had received a clinical or genetic diagnosis of FXS. In each case, physical and cognitive features were typical of FXS, and one man was also diagnosed with autism. Guided by reports of clinical and neuroimaging abnormalities of the limbic system and cerebellum of individuals with FXS, the current analysis focused on neuropathologic features present in the hippocampus and the cerebellar vermis. Results Histologic and immunologic staining revealed abnormalities in both the hippocampus and cerebellar vermis. Focal thickening of hippocampal CA1 and irregularities in the appearance of the dentate gyrus were identified. All lobules of the cerebellar vermis and the lateral cortex of the posterior lobe of the cerebellum had decreased numbers of Purkinje cells, which were occasionally misplaced, and often lacked proper orientation. There were mild, albeit excessive, undulations of the internal granular cell layer, with patchy foliar white matter axonal and astrocytic abnormalities. Quantitative analysis documented panfoliar atrophy of both the anterior and posterior lobes of the vermis, with preferential atrophy of the posterior lobule (VI to VII compared with age-matched normal controls. Conclusions Significant morphologic changes in the hippocampus and cerebellum in three adult men with FXS were identified. This pattern of pathologic features supports the idea that primary defects in neuronal migration, neurogenesis and aging may underlie the neuropathology reported in FXS.

  5. Neuropathologic features in the hippocampus and cerebellum of three older men with fragile X syndrome

    2011-01-01

    Background Fragile X syndrome (FXS) is the most common inherited form of intellectual disability, and is the most common single-gene disorder known to be associated with autism. Despite recent advances in functional neuroimaging and our understanding of the molecular pathogenesis, only limited neuropathologic information on FXS is available. Methods Neuropathologic examinations were performed on post-mortem brain tissue from three older men (aged 57, 64 and 78 years) who had received a clinical or genetic diagnosis of FXS. In each case, physical and cognitive features were typical of FXS, and one man was also diagnosed with autism. Guided by reports of clinical and neuroimaging abnormalities of the limbic system and cerebellum of individuals with FXS, the current analysis focused on neuropathologic features present in the hippocampus and the cerebellar vermis. Results Histologic and immunologic staining revealed abnormalities in both the hippocampus and cerebellar vermis. Focal thickening of hippocampal CA1 and irregularities in the appearance of the dentate gyrus were identified. All lobules of the cerebellar vermis and the lateral cortex of the posterior lobe of the cerebellum had decreased numbers of Purkinje cells, which were occasionally misplaced, and often lacked proper orientation. There were mild, albeit excessive, undulations of the internal granular cell layer, with patchy foliar white matter axonal and astrocytic abnormalities. Quantitative analysis documented panfoliar atrophy of both the anterior and posterior lobes of the vermis, with preferential atrophy of the posterior lobule (VI to VII) compared with age-matched normal controls. Conclusions Significant morphologic changes in the hippocampus and cerebellum in three adult men with FXS were identified. This pattern of pathologic features supports the idea that primary defects in neuronal migration, neurogenesis and aging may underlie the neuropathology reported in FXS. PMID:21303513

  6. The cerebellum and psychiatric disorders

    Joseph ePhillips

    2015-05-01

    Full Text Available The cerebellum has been considered for a long time to play a role solely in motor coordination. However, studies over the past two decades have shown that the cerebellum also plays a key role in many motor, cognitive, and emotional processes. In addition, studies have also shown that the cerebellum is implicated in many psychiatric disorders including attention deficit hyperactivity disorder, autism spectrum disorders, schizophrenia, bipolar disorder, major depressive disorder and anxiety disorders. In this review, we discuss existing studies reporting cerebellar dysfunction in various psychiatric disorders. We will also discuss future directions for studies linking the cerebellum to psychiatric disorders.

  7. Cerebellum and personality traits.

    Petrosini, Laura; Cutuli, Debora; Picerni, Eleonora; Laricchiuta, Daniela

    2015-02-01

    Personality traits are multidimensional traits comprising cognitive, emotional, and behavioral characteristics, and a wide array of cerebral structures mediate individual variability. Differences in personality traits covary with brain morphometry in specific brain regions. A cerebellar role in emotional and affective processing and on personality characteristics has been suggested. In a large sample of healthy subjects of both sexes and differently aged, the macro- and micro-structural variations of the cerebellum were correlated with the scores obtained in the Temperament and Character Inventory (TCI) by Cloninger. Cerebellar volumes were associated positively with Novelty Seeking scores and negatively with Harm Avoidance scores. Given the cerebellar contribution in personality traits and emotional processing, we investigated the cerebellar involvement even in alexithymia, construct of personality characterized by impairment in cognitive, emotional, and affective processing. Interestingly, the subjects with high alexithymic traits had larger volumes in the bilateral Crus 1. The cerebellar substrate for some personality dimensions extends the relationship between personality and brain areas to a structure up to now thought to be involved mainly in motor and cognitive functions, much less in emotional processes and even less in personality individual differences. The enlarged volumes of Crus 1 in novelty seekers and alexithymics support the tendency to action featuring both personality constructs. In fact, Novelty Seeking and alexithymia are rooted in behavior and inescapably have a strong action component, resulting in stronger responses in the structures more focused on action and embodiment, as the cerebellum is.

  8. Induction of brain CYP2E1 by chronic ethanol treatment and related oxidative stress in hippocampus, cerebellum, and brainstem

    Zhong, Yanjun; Dong, Guicheng; Luo, Haiguang; Cao, Jie; Wang, Chang; Wu, Jianyuan; Feng, Yu-Qi; Yue, Jiang

    2012-01-01

    Ethanol is one of the most commonly abused substances, and oxidative stress is an important causative factor in ethanol-induced neurotoxicity. Cytochrome P450 2E1 (CYP2E1) is involved in ethanol metabolism in the brain. This study investigates the role of brain CYP2E1 in the susceptibility of certain brain regions to ethanol neurotoxicity. Male Wistar rats were intragastrically treated with ethanol (3.0 g/kg, 30 days). CYP2E1 protein, mRNA expression, and catalytic activity in various brain regions were respectively assessed by immunoblotting, quantitative quantum dot immunohistochemistry, real-time RT-PCR, and LC–MS. The generation of reactive oxygen species (ROS) was analyzed using a laser confocal scanning microscope. The hippocampus, cerebellum, and brainstem were selectively damaged after ethanol treatment, indicated by both lactate dehydrogenase (LDH) activity and histopathological analysis. Ethanol markedly increased the levels of CYP2E1 protein, mRNA expression, and activity in the hippocampus and cerebellum. CYP2E1 protein and activity were significantly increased by ethanol in the brainstem, with no change in mRNA expression. ROS levels induced by ethanol paralleled the enhanced CYP2E1 proteins in the hippocampus, granular layer and white matter of cerebellum as well as brainstem. Brain CYP2E1 activity was positively correlated with the damage to the hippocampus, cerebellum, and brainstem. These results suggest that the selective sensitivity of brain regions to ethanol neurodegeneration may be attributed to the regional and cellular-specific induction of CYP2E1 by ethanol. The inhibition of CYP2E1 levels may attenuate ethanol-induced oxidative stress via ROS generation.

  9. An Evaluation of the Resilient Modulus and Permanent Deformation of Unbound Mixtures of Granular Materials and Rubber Particles from Scrap Tyres to Be Used in Subballast Layers

    Hidalgo Sgnes, C.

    2016-07-01

    Over the last years rubber from scrap tyres has been reused in different civil works such as road embankments and railway platforms due to its resilient properties, low degradation and vibration attenuation. Unfortunately, this issue is still scarce. For instance, in Spain about 175.000 tonnes of scrap tyres were collected in 2014, of which only 0.6% were reused in civil works. Aiming to contribute to the reutilisation of large quantities of this waste material, this paper focuses on the analysis of unbound mixtures of granular materials with different percentages of rubber particles to be used as subballast layers. Mixtures are tested under cyclic triaxial tests so as to obtain their resilient modulus and evaluate their permanent deformations. It is found that as the rubber content increases, the resilient modulus decreases and the permanent deformation increases. Taking into account the usual loads transmitted to the subballast layer, the optimum rubber content that does not compromise the behaviour of the mixture is set in a range between 2.5% and 5% in terms of weight. (Author)

  10. Regional functionality of the cerebellum

    Witter, Laurens; De Zeeuw, Chris I

    2015-01-01

    Over the recent years, advances in brain imaging, optogenetics and viral tracing have greatly advanced our understanding of the cerebellum and its connectivity. It has become clear that the cerebellum can be divided into functional units, each connected with particular brain areas involved in

  11. Measurement of Biocolloid Collision Efficiencies for Granular Activated Carbon by Use of a Two-Layer Filtration Model

    Paramonova, Ekaterina; Zerfoss, Erica L.; Logan, Bruce E.

    2006-01-01

    Point-of-use filters containing granular activated carbon (GAC) are an effective method for removing certain chemicals from water, but their ability to remove bacteria and viruses has been relatively untested. Collision efficiencies (α) were determined using clean-bed filtration theory for two bacteria (Raoutella terrigena 33257 and Escherichia coli 25922), a bacteriophage (MS2), and latex microspheres for four GAC samples. These GAC samples had particle size distributions that were bimodal, but only a single particle diameter can be used in the filtration equation. Therefore, consistent with previous reports, we used a particle diameter based on the smallest diameter of the particles (derived from the projected areas of 10% of the smallest particles). The bacterial collision efficiencies calculated using the filtration model were high (0.8 ≤ α ≤ 4.9), indicating that GAC was an effective capture material. Collision efficiencies greater than unity reflect an underestimation of the collision frequency, likely as a result of particle roughness and wide GAC size distributions. The collision efficiencies for microspheres (0.7 ≤ α ≤ 3.5) were similar to those obtained for bacteria, suggesting that the microspheres were a reasonable surrogate for the bacteria. The bacteriophage collision efficiencies ranged from ≥0.2 to ≤0.4. The predicted levels of removal for 1-cm-thick carbon beds ranged from 0.8 to 3 log for the bacteria and from 0.3 to 1.0 log for the phage. These tests demonstrated that GAC can be an effective material for removal of bacteria and phage and that GAC particle size is a more important factor than relative stickiness for effective particle removal. PMID:16885264

  12. The Sleeping Cerebellum.

    Canto, Cathrin B; Onuki, Yoshiyuki; Bruinsma, Bastiaan; van der Werf, Ysbrand D; De Zeeuw, Chris I

    2017-05-01

    We sleep almost one-third of our lives and sleep plays an important role in critical brain functions like memory formation and consolidation. The role of sleep in cerebellar processing, however, constitutes an enigma in the field of neuroscience; we know little about cerebellar sleep-physiology, cerebro-cerebellar interactions during sleep, or the contributions of sleep to cerebellum-dependent memory consolidation. Likewise, we do not understand why cerebellar malfunction can lead to changes in the sleep-wake cycle and sleep disorders. In this review, we evaluate how sleep and cerebellar processing may influence one another and highlight which scientific routes and technical approaches could be taken to uncover the mechanisms underlying these interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. A fluidized layer of granular material used for the separation of particulate impurities in drinking water treatment

    Pivokonský, Martin; Bubáková, Petra; Hnaťuková, Petra; Knesl, Bohuslav

    2011-01-01

    Roč. 59, č. 2 (2011), s. 95-106 ISSN 0042-790X R&D Projects: GA AV ČR IAA200600902 Institutional research plan: CEZ:AV0Z20600510 Keywords : aggregation * destabilization * fluidized layer * separation * water treatment Subject RIV: BK - Fluid Dynamics Impact factor: 0.340, year: 2011

  14. Aggregation capability of a fluidised layer of granular material during treatment of water with high DOC and low alkalinity

    Pivokonský, Martin; Pivokonská, Lenka; Tomášková, Hana

    2008-01-01

    Roč. 8, č. 1 (2008), s. 9-17 ISSN 1606-9749 R&D Projects: GA ČR GA103/07/1016 Institutional research plan: CEZ:AV0Z20600510 Keywords : water treatment * aggregation * fluidised layer * agitation Subject RIV: BK - Fluid Dynamics

  15. Dependence of magnetic properties on ferromagnetic layer thickness in trilayer Co/Ge/Co films with granular semiconducting spacer

    Patrin, G.S.; Lee, C.-G.; Turpanov, I.A.; Zharkov, S.M.; Velikanov, D.A.; Maltsev, V.K.; Li, L.A.; Lantsev, V.V.

    2006-01-01

    We have investigated the magnetic properties of trilayer films of Co-Ge-Co. At a fixed thickness of germanium of 3.5 nm, the formation and distribution of metastable amorphous and cubic phases depends on the thickness of the ferromagnetic layer. The portion of the stable hexagonal phase is affected, too. Possible mechanisms for forming the observed magnetic structure are discussed

  16. METHOD FOR DETERMINATION OF THERMAL CHARACTERISTICS OF THE LAYER OF GRANULAR MEDIA WITH ELEMENTS OF PULSED THERMAL NDT

    Y. V. Shokina

    2015-01-01

    Full Text Available At the Department of Food Production of Murmansk State Technical University (MSTU was developed a method of producing smoke fuel using infrared energy supply. The method provides a stable temperature pyrolysis of wood fuel is less than 400 ° C. Kinetic of the heating layer of fuel (wooden chips is affected by chip's density and moisture content. The method of calculating of the optimum modes of smoke produce, which is based on a system of differential equations of heat and mass transfer in the IR smoke generator, was previously proposed. The system of equations includes thermal characteristics (TC of the fuel layer (e.g. specific heat, thermal conductivity, thermal diffusivity. The exact definition of these characteristics affect the accuracy of the experimental calculation of optimal process conditions with use of the developed software. A definition of layer's TC by a method with elements of pulsed thermal NDT. The use of thermal imager is proposed for measuring the temperature of the irritated surface of the porous wooden chip's lawyer.

  17. Increase of the blocking temperature of Fe–Ag granular multilayers with increasing number of the layers

    Balogh, Judit [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Kaptás, Dénes, E-mail: kaptas.denes@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Kiss, László F. [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Dézsi, István [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Nakanishi, Akio [Department of Physics, Shiga University of Medical Science, Shiga 520-2192 (Japan); Devlin, Eamonn; Vasilakaki, Marianna; Margaris, George; Trohidou, Kalliopi N. [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, Aghia Paraskevi, 15310 Athens (Greece)

    2016-03-01

    Multilayers of 0.4 nm Fe and 5 nm Ag with repetition number, n=1, 2, 5, 10 and 20 were prepared by vacuum evaporation onto Si wafer. The blocking temperature was determined by measuring the field cooled and zero field cooled magnetization curves with a SQUID magnetometer and it was found to increase by almost an order of magnitude from around 20 K for the single Fe layer sample up to around 160 K for n=20. Significant increase of the average size of the superparamagnetic Fe grains by increasing the number of the Fe layers was excluded by conversion electron Mössbauer spectroscopy measurements of the paramagnetic state. The role of the dipole–dipole interactions and their interplay with the out-of-plain magnetic anisotropy in the variation of the blocking temperature has been investigated by Monte-Carlo simulations. - Highlights: • Multilayers of [0.4 nm Fe/5 nm Ag]{sub n} (n=1,2,5,10, and 20) were grown over Si. • Large increase of the superparamagnetic blocking temperature up to n=10 is observed. • The average Fe grain size does not change in the subsequent layers. • Perpendicular anisotropy enhances the dipolar coupling and the blocking temperature.

  18. Spike timing regulation on the millisecond scale by distributed synaptic plasticity at the cerebellum input stage: a simulation study

    Jesus A Garrido

    2013-05-01

    Full Text Available The way long-term synaptic plasticity regulates neuronal spike patterns is not completely understood. This issue is especially relevant for the cerebellum, which is endowed with several forms of long-term synaptic plasticity and has been predicted to operate as a timing and a learning machine. Here we have used a computational model to simulate the impact of multiple distributed synaptic weights in the cerebellar granular layer network. In response to mossy fiber bursts, synaptic weights at multiple connections played a crucial role to regulate spike number and positioning in granule cells. The weight at mossy fiber to granule cell synapses regulated the delay of the first spike and the weight at mossy fiber and parallel fiber to Golgi cell synapses regulated the duration of the time-window during which the first-spike could be emitted. Moreover, the weights of synapses controlling Golgi cell activation regulated the intensity of granule cell inhibition and therefore the number of spikes that could be emitted. First spike timing was regulated with millisecond precision and the number of spikes ranged from 0 to 3. Interestingly, different combinations of synaptic weights optimized either first-spike timing precision or spike number, efficiently controlling transmission and filtering properties. These results predict that distributed synaptic plasticity regulates the emission of quasi-digital spike patterns on the millisecond time scale and allows the cerebellar granular layer to flexibly control burst transmission along the mossy fiber pathway.

  19. Sensitivity difference between anterior and posterior lobes of rat cerebellum to prenatal exposure to 2.5 Gy X-irradiation. A histological study

    Darmanto, W.; Hayasaka, Shizu; Takagishi, Yoshiko; Aolad, H.M.; Inouye, Minoru

    1997-01-01

    We investigated the histological differences in abnormality between anterior lobes (vermian lobules II, III and culmen IV, V) and posterior lobes (lobules IX, X) of the rat cerebellum following prenatal exposure to X-irradiation. Pregnant rats were exposed to 2.5 Gy X-irradiation at gestation day-21 (GD-21), and pups were sacrificed from birth through 15 days of age. Their cerebella were examined histologically and immunohistochemically for glial fibrillary acidic protein in Bergmann fibers. Extensive cell death was found in the external granular layer (EGL) of the cerebellum on the day of birth. In the anterior lobes, the number of cell deaths was higher than in the posterior lobes. During 5 days after birth, the recovery of EGL was earlier in the posterior lobes than in the anterior lobes. Seven days after birth, Bergmann fibers were more irregular in the anterior lobes than in the posterior lobes. The number of Purkinje cells in ectopic locations was higher in the anterior lobes than in the posterior lobes. The EGL and migrating Purkinje cells showed different responses to X-irradiation in the anterior than in the posterior lobes of the cerebellum. (author)

  20. The cerebellum mediates conflict resolution.

    Schweizer, Tom A; Oriet, Chris; Meiran, Nachshon; Alexander, Michael P; Cusimano, Michael; Stuss, Donald T

    2007-12-01

    Regions within the frontal and parietal cortex have been implicated as important neural correlates for cognitive control during conflict resolution. Despite the extensive reciprocal connectivity between the cerebellum and these putatively critical cortical areas, a role for the cerebellum in conflict resolution has never been identified. We used a task-switching paradigm that separates processes related to task-set switching and the management of response conflict independent of motor processing. Eleven patients with chronic, focal lesions to the cerebellum and 11 healthy controls were compared. Patients were slower and less accurate in conditions involving conflict resolution. In the absence of response conflict, however, tasks-witching abilities were not impaired in our patients. The cerebellum may play an important role in coordinating with other areas of cortex to modulate active response states. These results are the first demonstration of impaired conflict resolution following cerebellar lesions in the presence of an intact prefrontal cortex.

  1. The Cerebellum and Its Wrapping Meninge: Developmental Interplay between Two Major Structures.

    Catala, Martin

    2017-10-01

    Meninges have long been considered as a protective and supportive tissue for the central nervous system. Nevertheless, new developmental roles are now attributed to them. The meninges that surround the cerebellum come from the cephalic mesoderm. They are essential for the cerebellum to develop normally. They induce and maintain the basal lamina and glia limitans. In the absence of these structures, the external granular cells of the cerebellum migrate aberrantly and penetrate the subarachnoid space. The molecules involved in the recognition between the cerebellar primordium and the basal lamina belong to two groups in humans: dystroglycan and laminin on the one hand, and GPR56 and collagen III on the other. Finally, molecules secreted by the meninges and acting on the cerebellum begin to be demonstrated; such is the case of SDF1 secreted under the action of FOXC1. Georg Thieme Verlag KG Stuttgart · New York.

  2. Consensus Paper: Cerebellum and Emotion.

    Adamaszek, M; D'Agata, F; Ferrucci, R; Habas, C; Keulen, S; Kirkby, K C; Leggio, M; Mariën, P; Molinari, M; Moulton, E; Orsi, L; Van Overwalle, F; Papadelis, C; Priori, A; Sacchetti, B; Schutter, D J; Styliadis, C; Verhoeven, J

    2017-04-01

    Over the past three decades, insights into the role of the cerebellum in emotional processing have substantially increased. Indeed, methodological refinements in cerebellar lesion studies and major technological advancements in the field of neuroscience are in particular responsible to an exponential growth of knowledge on the topic. It is timely to review the available data and to critically evaluate the current status of the role of the cerebellum in emotion and related domains. The main aim of this article is to present an overview of current facts and ongoing debates relating to clinical, neuroimaging, and neurophysiological findings on the role of the cerebellum in key aspects of emotion. Experts in the field of cerebellar research discuss the range of cerebellar contributions to emotion in nine topics. Topics include the role of the cerebellum in perception and recognition, forwarding and encoding of emotional information, and the experience and regulation of emotional states in relation to motor, cognitive, and social behaviors. In addition, perspectives including cerebellar involvement in emotional learning, pain, emotional aspects of speech, and neuropsychiatric aspects of the cerebellum in mood disorders are briefly discussed. Results of this consensus paper illustrate how theory and empirical research have converged to produce a composite picture of brain topography, physiology, and function that establishes the role of the cerebellum in many aspects of emotional processing.

  3. Gene transfer to the cerebellum.

    Louboutin, Jean-Pierre; Reyes, Beverly A S; Van Bockstaele, Elisabeth J; Strayer, David S

    2010-12-01

    There are several diseases for which gene transfer therapy to the cerebellum might be practicable. In these studies, we used recombinant Tag-deleted SV40-derived vectors (rSV40s) to study gene delivery targeting the cerebellum. These vectors transduce neurons and microglia very effectively in vitro and in vivo, and so we tested them to evaluate gene transfer to the cerebellum in vivo. Using a rSV40 vector carrying human immunodeficiency virus (HIV)-Nef with a C-terminal FLAG epitope, we characterized the distribution, duration, and cell types transduced. Rats received test and control vectors by stereotaxic injection into the cerebellum. Transgene expression was assessed 1, 2, and 4 weeks later by immunostaining of serial brain sections. FLAG epitope-expressing cells were seen, at all times after vector administration, principally detected in the Purkinje cells of the cerebellum, identified as immunopositive for calbindin. Occasional microglial cells were tranduced; transgene expression was not detected in astrocytes or oligodendrocytes. No inflammatory or other reaction was detected at any time. Thus, SV40-derived vectors can deliver effective, safe, and durable transgene expression to the cerebellum.

  4. The effects of early hypo- and hyperthyroidism on the development of rat cerebellar cortex. III. Kinetics of cell proliferation in the external granular layer.

    Lauder, J M

    1977-04-22

    The effects of early hypo- and hyperthyroidism on the rates of cell acquisition and proliferation have been studied in the external granular layer (EGL) of the developing rat cerebellar cortex at 10 days of age using quantitative autoradiographic methods. Both altered thyroid states reduce the rate of cell acquisition in the EGL, but appear to do so for different reasons. Hyperthyroidism shortens the average length of the cell cycle by decreasing the duration of the pre-DNA synthetic phase (G1), indicating that excess thyroxine may exert a direct effect on the EGL. This action involves the early onset of neuronal differentiation (cessation of proliferation)46 which presumably leads to the observed decrease in the rate of cell acquisition (increased doubling time). Such differentiating cells do not, however, leave the proliferative zone or the EGL prematurely, resulting in a reduced labeling index, mitotic index, and growth fraction as non-dividing cells dilute the proliferating cell population. Hypothyroidism, on the other hand, leads to no significant change in the length of the cell cycle or in the mitotic index, but causes a decreased labeling index and growth fraction, as well as a reduced rate of cell acquisition (increased doubling time). No significant change in the amount of cell death in the EGL could be found to explain this apparent discrepancy between the rate of cell proliferation (cell cycle length) and cell acqusiition. The answer to this puzzle appears to lie in the mitotic index, which is not affected to the same extent as the labeling index, although it is also slightly reduced. If cells were to remain longer in mitosis, this could result in a decreased labeling index and growth fraction but nearly normal mitotic index and cell cycle length (as measured using the % labeled mitoses method), since those cells dropping out of the cycling population would be counted as mitoses...

  5. The Cerebellum and Neurodevelopmental Disorders.

    Stoodley, Catherine J

    2016-02-01

    Cerebellar dysfunction is evident in several developmental disorders, including autism, attention deficit-hyperactivity disorder (ADHD), and developmental dyslexia, and damage to the cerebellum early in development can have long-term effects on movement, cognition, and affective regulation. Early cerebellar damage is often associated with poorer outcomes than cerebellar damage in adulthood, suggesting that the cerebellum is particularly important during development. Differences in cerebellar development and/or early cerebellar damage could impact a wide range of behaviors via the closed-loop circuits connecting the cerebellum with multiple cerebral cortical regions. Based on these anatomical circuits, behavioral outcomes should depend on which cerebro-cerebellar circuits are affected. Here, we briefly review cerebellar structural and functional differences in autism, ADHD, and developmental dyslexia, and discuss clinical outcomes following pediatric cerebellar damage. These data confirm the prediction that abnormalities in different cerebellar subregions produce behavioral symptoms related to the functional disruption of specific cerebro-cerebellar circuits. These circuits might also be crucial to structural brain development, as peri-natal cerebellar lesions have been associated with impaired growth of the contralateral cerebral cortex. The specific contribution of the cerebellum to typical development may therefore involve the optimization of both the structure and function of cerebro-cerebellar circuits underlying skill acquisition in multiple domains; when this process is disrupted, particularly in early development, there could be long-term alterations of these neural circuits, with significant impacts on behavior.

  6. Granular flows in constrained geometries

    Murthy, Tejas; Viswanathan, Koushik

    Confined geometries are widespread in granular processing applications. The deformation and flow fields in such a geometry, with non-trivial boundary conditions, determine the resultant mechanical properties of the material (local porosity, density, residual stresses etc.). We present experimental studies of deformation and plastic flow of a prototypical granular medium in different nontrivial geometries- flat-punch compression, Couette-shear flow and a rigid body sliding past a granular half-space. These geometries represent simplified scaled-down versions of common industrial configurations such as compaction and dredging. The corresponding granular flows show a rich variety of flow features, representing the entire gamut of material types, from elastic solids (beam buckling) to fluids (vortex-formation, boundary layers) and even plastically deforming metals (dead material zone, pile-up). The effect of changing particle-level properties (e.g., shape, size, density) on the observed flows is also explicitly demonstrated. Non-smooth contact dynamics particle simulations are shown to reproduce some of the observed flow features quantitatively. These results showcase some central challenges facing continuum-scale constitutive theories for dynamic granular flows.

  7. Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum

    Inouye, Minoru; Yamamura, Hideki; Nakano, Atsuhiro.

    1995-01-01

    Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 μmol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 μg/g at the time of irradiation and remaining at more than 40 μg/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositide-mediated signaling systems regulate radiation-induced apoptosis. (author)

  8. Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum.

    Inouye, M; Yamamura, H; Nakano, A

    1995-09-01

    Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 mumol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 micrograms/g at the time of irradiation and remaining at more than 40 micrograms/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositidemediated signaling systems regulate radiation-induced apoptosis.

  9. Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum

    Inouye, Minoru; Yamamura, Hideki [Nagoya Univ. (Japan). Research Inst. of Environmental Medicine; Nakano, Atsuhiro

    1995-09-01

    Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 {mu}mol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 {mu}g/g at the time of irradiation and remaining at more than 40 {mu}g/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositide-mediated signaling systems regulate radiation-induced apoptosis. (author).

  10. Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons.

    Martí, Joaquín; Santa-Cruz, M C; Serra, Roger; Hervás, José P

    2016-11-01

    The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.

  11. Does the cerebellum initiate movement?

    Thach, W T

    2014-02-01

    Opinion is divided on what the exact function of the cerebellum is. Experiments are summarized that support the following views: (1) the cerebellum is a combiner of multiple movement factors; (2) it contains anatomically fixed permanent focal representation of individual body parts (muscles and segments) and movement modes (e.g., vestibular driven vs. cognitive driven); (3) it contains flexible changing representations/memory of physical properties of the body parts including muscle strength, segment inertia, joint viscosity, and segmental interaction torques (dynamics); (4) it contains mechanisms for learning and storage of the properties in item no. 3 through trial-and-error practice; (5) it provides for linkage of body parts, motor modes, and motordynamics via the parallel fiber system; (6) it combines and integrates the many factors so as to initiate coordinated movements of the many body parts; (7) it is thus enabled to play the unique role of initiating coordinated movements; and (8) this unique causative role is evidenced by the fact that: (a) electrical stimulation of the cerebellum can initiate compound coordinated movements; (b) in naturally initiated compound movements, cerebellar discharge precedes that in downstream target structures such as motor cerebral cortex; and (c) cerebellar ablation abolishes the natural production of compound movements in the awake alert individuals.

  12. Trace element distribution in the rat cerebellum

    Kwiatek, W.M.; Long, G.J.; Pounds, J.G.; Reuhl, K.R.; Hanson, A.L.; Jones, K.W.

    1989-10-01

    Spatial distributions and concentrations of trace elements (TE) in the brain are important because TE perform catalytic structural functions in enzymes which regulate brain function and development. We have investigated the distributions of TE in rat cerebellum. Structures were sectioned and analyzed by the Synchrotron Radiation Induced X-ray Emission (SRIXE) method using the NSLS X-26 white-light microprobe facility. Advantages important for TE analysis of biological specimens with x-ray microscopy include short time of measurement, high brightness and flux, good spatial resolution, multielemental detection, good sensitivity, and non-destructive irradiation. Trace elements were measured in thin rat brain sections of 20-micrometers thickness. The analyses were performed on sample volumes as small as 0.2 nl with Minimum Detectable Limits (MDL) of 50 ppb wet weight for Fe, 100 ppb wet weight for Cu, and Zn, and 1 ppM wet weight for Pb. The distribution of TE in the molecular cell layer, granule cell layer and fiber tract of rat cerebella was investigated. Both point analyses and two-dimensional semi-quantitative mapping of the TE distribution in a section were used

  13. Granular Leidenfrost effect: Experiment and theory of floating particle clusters

    Eshuis, Peter; Eshuis, P.G.; van der Meer, Roger M.; van der Weele, J.P.; Lohse, Detlef

    2005-01-01

    Granular material is vertically vibrated in a 2D container: above a critical shaking strength, and for a sufficient number of beads, a crystalline cluster is elevated and supported by a dilute gaseous layer of fast beads underneath. We call this phenomenon the granular Leidenfrost effect. The

  14. Serotonergic control of the developing cerebellum

    Oostland, M.

    2013-01-01

    The work described in this thesis gives insights in the mechanism behind the serotonergic control of the cerebellum during postnatal development. The findings present a powerful role for serotonin in the physiology of the developing cerebellum. The effects of the serotonergic control extend both

  15. Mosaic Expression of Thyroid Hormone Regulatory Genes Defines Cell Type-Specific Dependency in the Developing Chicken Cerebellum.

    Delbaere, Joke; Van Herck, Stijn L J; Bourgeois, Nele M A; Vancamp, Pieter; Yang, Shuo; Wingate, Richard J T; Darras, Veerle M

    2016-12-01

    The cerebellum is a morphologically unique brain structure that requires thyroid hormones (THs) for the correct coordination of key cellular events driving its development. Unravelling the interplay between the multiple factors that can regulate intracellular TH levels is a key step to understanding their role in the regulation of these cellular processes. We therefore investigated the regional/cell-specific expression pattern of TH transporters and deiodinases in the cerebellum using the chicken embryo as a model. In situ hybridisation revealed expression of the TH transporters monocarboxylate transporter 8 (MCT8) and 10 (MCT10), L-type amino acid transporter 1 (LAT1) and organic anion transporting polypeptide 1C1 (OATP1C1) as well as the inactivating type 3 deiodinase (D3) in the fourth ventricle choroid plexus, suggesting a possible contribution of the resulting proteins to TH exchange and subsequent inactivation of excess hormone at the blood-cerebrospinal fluid barrier. Exclusive expression of LAT1 and the activating type 2 deiodinase (D2) mRNA was found at the level of the blood-brain barrier, suggesting a concerted function for LAT1 and D2 in the direct access of active T 3 to the developing cerebellum via the capillary endothelial cells. The presence of MCT8 mRNA in Purkinje cells and cerebellar nuclei during the first 2 weeks of embryonic development points to a potential role of this transporter in the uptake of T 3 in central neurons. At later stages, together with MCT10, detection of MCT8 signal in close association with the Purkinje cell dendritic tree suggests a role of both transporters in TH signalling during Purkinje cell synaptogenesis. MCT10 was also expressed in late-born cells in the rhombic lip lineage with a clear hybridisation signal in the outer external granular layer, indicating a potential role for MCT10 in the proliferation of granule cell precursors. By contrast, expression of D3 in the first-born rhombic lip-derived population may

  16. The Granular Blasius Problem: High inertial number granular flows

    Tsang, Jonathan; Dalziel, Stuart; Vriend, Nathalie

    2017-11-01

    The classical Blasius problem considers the formation of a boundary layer through the change at x = 0 from a free-slip to a no-slip boundary beneath an otherwise steady uniform flow. Discrete particle model (DPM) simulations of granular gravity currents show that a similar phenomenon exists for a steady flow over a uniformly sloped surface that is smooth upstream (allowing slip) but rough downstream (imposing a no-slip condition). The boundary layer is a region of high shear rate and therefore high inertial number I; its dynamics are governed by the asymptotic behaviour of the granular rheology as I -> ∞ . The μ(I) rheology asserts that dμ / dI = O(1 /I2) as I -> ∞ , but current experimental evidence is insufficient to confirm this. We show that `generalised μ(I) rheologies', with different behaviours as I -> ∞ , all permit the formation of a boundary layer. We give approximate solutions for the velocity profile under each rheology. The change in boundary condition considered here mimics more complex topography in which shear stress increases in the streamwise direction (e.g. a curved slope). Such a system would be of interest in avalanche modelling. EPSRC studentship (Tsang) and Royal Society Dorothy Hodgkin Fellowship (Vriend).

  17. HYPERELASTIC MODELS FOR GRANULAR MATERIALS

    Humrickhouse, Paul W; Corradini, Michael L

    2009-01-29

    A continuum framework for modeling of dust mobilization and transport, and the behavior of granular systems in general, has been reviewed, developed and evaluated for reactor design applications. The large quantities of micron-sized particles expected in the international fusion reactor design, ITER, will accumulate into piles and layers on surfaces, which are large relative to the individual particle size; thus, particle-particle, rather than particle-surface, interactions will determine the behavior of the material in bulk, and a continuum approach is necessary and justified in treating the phenomena of interest; e.g., particle resuspension and transport. The various constitutive relations that characterize these solid particle interactions in dense granular flows have been discussed previously, but prior to mobilization their behavior is not even fluid. Even in the absence of adhesive forces between particles, dust or sand piles can exist in static equilibrium under gravity and other forces, e.g., fluid shear. Their behavior is understood to be elastic, though not linear. The recent “granular elasticity” theory proposes a non-linear elastic model based on “Hertz contacts” between particles; the theory identifies the Coulomb yield condition as a requirement for thermodynamic stability, and has successfully reproduced experimental results for stress distributions in sand piles. The granular elasticity theory is developed and implemented in a stand- alone model and then implemented as part of a finite element model, ABAQUS, to determine the stress distributions in dust piles subjected to shear by a fluid flow. We identify yield with the onset of mobilization, and establish, for a given dust pile and flow geometry, the threshold pressure (force) conditions on the surface due to flow required to initiate it. While the granular elasticity theory applies strictly to cohesionless granular materials, attractive forces are clearly important in the interaction of

  18. Spatiotemporal expression of chondroitin sulfate sulfotransferases in the postnatal developing mouse cerebellum.

    Ishii, Maki; Maeda, Nobuaki

    2008-08-01

    Chondroitin sulfate (CS) proteoglycans are major components of the cell surface and the extracellular matrix in the developing brain and bind to various proteins via CS chains in a CS structure-dependent manner. This study demonstrated the expression pattern of three CS sulfotransferase genes, dermatan 4-O-sulfotransferase (D4ST), uronyl 2-O-sulfotransferase (UST), and N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST), in the mouse postnatal cerebellum. These sulfotransferases are responsible for the biosynthesis of oversulfated structures in CS chains such as B, D, and E units, which constitute the binding sites for various heparin-binding proteins. Real-time reverse transcription-polymerase chain reaction analysis indicated that the expression of UST increased remarkably during cerebellar development. The amounts of B and D units, which are generated by UST activity, in the cerebellar CS chains also increased during development. In contrast, the expression of GalNAc4S-6ST and its biosynthetic product, E unit, decreased during postnatal development. In situ hybridization experiments revealed the levels of UST and GalNAc4S-6ST mRNAs to correlate inversely in many cells including Purkinje cells, granule cells in the external granular layer, and inhibitory interneurons. In these neurons, the expression of UST increased and that of GalNAc4S-6ST decreased during development and/or maturation. D4ST was also expressed by many neurons, but its expression was not simply correlated with development, which might contribute to the diversification of CS structures expressed by distinct neurons. These results suggest that the CS structures of various cerebellar neurons change during development and such changes of CS are involved in the regulation of various signaling pathways.

  19. Factors influencing the density of aerobic granular sludge.

    Winkler, M.K.; Kleerebezem, R.; Strous, M.; Chandran, K.; Loosdrecht, M.C. van

    2013-01-01

    In the present study, the factors influencing density of granular sludge particles were evaluated. Granules consist of microbes, precipitates and of extracellular polymeric substance. The volume fractions of the bacterial layers were experimentally estimated by fluorescent in situ hybridisation

  20. CERES: A new cerebellum lobule segmentation method.

    Romero, Jose E; Coupé, Pierrick; Giraud, Rémi; Ta, Vinh-Thong; Fonov, Vladimir; Park, Min Tae M; Chakravarty, M Mallar; Voineskos, Aristotle N; Manjón, Jose V

    2017-02-15

    The human cerebellum is involved in language, motor tasks and cognitive processes such as attention or emotional processing. Therefore, an automatic and accurate segmentation method is highly desirable to measure and understand the cerebellum role in normal and pathological brain development. In this work, we propose a patch-based multi-atlas segmentation tool called CERES (CEREbellum Segmentation) that is able to automatically parcellate the cerebellum lobules. The proposed method works with standard resolution magnetic resonance T1-weighted images and uses the Optimized PatchMatch algorithm to speed up the patch matching process. The proposed method was compared with related recent state-of-the-art methods showing competitive results in both accuracy (average DICE of 0.7729) and execution time (around 5 minutes). Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Dissecting the links between cerebellum and dystonia.

    Malone, Ailish; Manto, Mario; Hass, Chris

    2014-12-01

    Dystonia is a common movement disorder characterized by sustained muscle contractions. These contractions generate twisting and repetitive movements or typical abnormal postures, often exacerbated by voluntary movement. Dystonia can affect almost all the voluntary muscles. For several decades, the discussion on the pathogenesis has been focused on basal ganglia circuits, especially striatal networks. So far, although dystonia has been observed in some forms of ataxia such as dominant ataxias, the link between the cerebellum and dystonia has remained unclear. Recent human studies and experimental data mainly in rodents show that the cerebellum circuitry could also be a key player in the pathogenesis of some forms of dystonia. In particular, studies based on behavioral adaptation paradigm shed light on the links between dystonia and cerebellum. The spectrum of movement disorders in which the cerebellum is implicated is continuously expanding, and manipulation of cerebellar circuits might even emerge as a candidate therapy in the coming years.

  2. Kinetic Monte Carlo simulations of the effect of the exchange control layer thickness in CoPtCrB/CoPtCrSiO granular media

    Almudallal, Ahmad M.; Mercer, J. I.; Whitehead, J. P.; Plumer, M. L.; van Ek, J.

    2018-05-01

    A hybrid Landau Lifshitz Gilbert/kinetic Monte Carlo algorithm is used to simulate experimental magnetic hysteresis loops for dual layer exchange coupled composite media. The calculation of the rate coefficients and difficulties arising from low energy barriers, a fundamental problem of the kinetic Monte Carlo method, are discussed and the methodology used to treat them in the present work is described. The results from simulations are compared with experimental vibrating sample magnetometer measurements on dual layer CoPtCrB/CoPtCrSiO media and a quantitative relationship between the thickness of the exchange control layer separating the layers and the effective exchange constant between the layers is obtained. Estimates of the energy barriers separating magnetically reversed states of the individual grains in zero applied field as well as the saturation field at sweep rates relevant to the bit write speeds in magnetic recording are also presented. The significance of this comparison between simulations and experiment and the estimates of the material parameters obtained from it are discussed in relation to optimizing the performance of magnetic storage media.

  3. The Cerebellum, Sensitive Periods, and Autism

    Wang, Samuel S.-H.; Kloth, Alexander D.; Badura, Aleksandra

    2014-01-01

    Cerebellar research has focused principally on adult motor function. However, the cerebellum also maintains abundant connections with nonmotor brain regions throughout postnatal life. Here we review evidence that the cerebellum may guide the maturation of remote nonmotor neural circuitry and influence cognitive development, with a focus on its relationship with autism. Specific cerebellar zones influence neocortical substrates for social interaction, and we propose that sensitive-period disruption of such internal brain communication can account for autism's key features. PMID:25102558

  4. Granular gas dynamics

    Brilliantov, Nikolai

    2003-01-01

    While there is not yet any general theory for granular materials, significant progress has been achieved for dilute systems, also called granular gases. The contributions in this book address both the kinetic approach one using the Boltzmann equation for dissipative gases as well as the less established hydrodynamic description. The last part of the book is devoted to driven granular gases and their analogy with molecular fluids. Care has been taken so as to present the material in a pedagogical and self-contained way and this volume will thus be particularly useful to nonspecialists and newcomers to the field.

  5. Cell-type-specific expression of NFIX in the developing and adult cerebellum.

    Fraser, James; Essebier, Alexandra; Gronostajski, Richard M; Boden, Mikael; Wainwright, Brandon J; Harvey, Tracey J; Piper, Michael

    2017-07-01

    Transcription factors from the nuclear factor one (NFI) family have been shown to play a central role in regulating neural progenitor cell differentiation within the embryonic and post-natal brain. NFIA and NFIB, for instance, promote the differentiation and functional maturation of granule neurons within the cerebellum. Mice lacking Nfix exhibit delays in the development of neuronal and glial lineages within the cerebellum, but the cell-type-specific expression of this transcription factor remains undefined. Here, we examined the expression of NFIX, together with various cell-type-specific markers, within the developing and adult cerebellum using both chromogenic immunohistochemistry and co-immunofluorescence labelling and confocal microscopy. In embryos, NFIX was expressed by progenitor cells within the rhombic lip and ventricular zone. After birth, progenitor cells within the external granule layer, as well as migrating and mature granule neurons, expressed NFIX. Within the adult cerebellum, NFIX displayed a broad expression profile, and was evident within granule cells, Bergmann glia, and interneurons, but not within Purkinje neurons. Furthermore, transcriptomic profiling of cerebellar granule neuron progenitor cells showed that multiple splice variants of Nfix are expressed within this germinal zone of the post-natal brain. Collectively, these data suggest that NFIX plays a role in regulating progenitor cell biology within the embryonic and post-natal cerebellum, as well as an ongoing role within multiple neuronal and glial populations within the adult cerebellum.

  6. Dynamic Deformation and Collapse of Granular Columns

    Uenishi, K.; Tsuji, K.; Doi, S.

    2009-12-01

    Large dynamic deformation of granular materials may be found in nature not only in the failure of slopes and cliffs — due to earthquakes, rock avalanches, debris flows and landslides — but also in earthquake faulting itself. Granular surface flows often consist of solid grains and intergranular fluid, but the effect of the fluid may be usually negligible because the volumetric concentration of grains is in many cases high enough for interparticle forces to dominate momentum transport. Therefore, the investigation of dry granular flow of a mass might assist in further understanding of the above mentioned geophysical events. Here, utilizing a high-speed digital video camera system, we perform a simple yet fully-controlled series of laboratory experiments related to the collapse of granular columns. We record, at an interval of some microseconds, the dynamic transient granular mass flow initiated by abrupt release of a tube that contains dry granular materials. The acrylic tube is partially filled with glass beads and has a cross-section of either a fully- or semi-cylindrical shape. Upon sudden removal of the tube, the granular solid may fragment under the action of its own weight and the particles spread on a rigid horizontal plane. This study is essentially the extension of the previous ones by Lajeunesse et al. (Phys. Fluids 2004) and Uenishi and Tsuji (JPGU 2008), but the striped layers of particles in a semi-cylindrical tube, newly introduced in this contribution, allow us to observe the precise particle movement inside the granular column: The development of slip lines inside the column and the movement of particles against each other can be clearly identified. The major controlling parameters of the spreading dynamics are the initial aspect ratio of the granular (semi-)cylindrical column, the frictional properties of the horizontal plane (substrate) and the size of beads. We show the influence of each parameter on the average flow velocity and final radius

  7. Granular computing: perspectives and challenges.

    Yao, JingTao; Vasilakos, Athanasios V; Pedrycz, Witold

    2013-12-01

    Granular computing, as a new and rapidly growing paradigm of information processing, has attracted many researchers and practitioners. Granular computing is an umbrella term to cover any theories, methodologies, techniques, and tools that make use of information granules in complex problem solving. The aim of this paper is to review foundations and schools of research and to elaborate on current developments in granular computing research. We first review some basic notions of granular computing. Classification and descriptions of various schools of research in granular computing are given. We also present and identify some research directions in granular computing.

  8. Effects of perinatal hypo- and hyperthyroidism on the levels of nerve growth factor and its low-affinity receptor in cerebellum.

    Figueiredo, B C; Otten, U; Strauss, S; Volk, B; Maysinger, D

    1993-04-16

    Deficits or excesses of thyroid hormones during critical periods of mammalian cerebellar development can lead to profound biochemical and morphological abnormalities in this system. The goal of this study was to investigate the effects of perinatal hypo- and hyperthyroidism on the ontogeny of nerve growth factor (NGF) and its low-affinity receptor (p75NGFR) in the rat cerebellum. The concentration of NGF and of p75NGFR immunoreactivity (IR) were measured, several days after birth, in cerebella of rats which had received propylthiouracil (PTU) or thyroxine. NGF concentration was markedly enhanced only on postnatal day 2 (P2) in hyperthyroid rats, whereas in hypothyroid (PTU-treated) rats NGF values were similar to age-matched controls. These observations suggest that thyroid hormone affects NGF synthesis during early periods of cerebellar development. In Purkinje cells of control animals, p75NGFR IR peaked at P10. In hypothyroid rats, the expression of p75NGFR was retarded, peaking at P15, whereas in hyperthyroid rats it was advanced, peaking at P8. The increased p75NGFR IR found in Purkinje cell bodies and the delayed disappearance of p75NGFR IR from the external granular layer of hypothyroid rats suggest different roles for thyroid hormone in the developing cerebellum. We conclude that p75NGFR and NGF are independently regulated by thyroid hormone during critical periods of cerebellar development. The effect of thyroid hormone deficiency on p75NGFR content in Purkinje cells may involve complex mechanisms such as impaired efficiency of axonal transport.

  9. Intelligent Network Management and Functional Cerebellum Synthesis

    Loebner, Egon E.

    1989-01-01

    Transdisciplinary modeling of the cerebellum across histology, physiology, and network engineering provides preliminary results at three organization levels: input/output links to central nervous system networks; links between the six neuron populations in the cerebellum; and computation among the neurons of the populations. Older models probably underestimated the importance and role of climbing fiber input which seems to supply write as well as read signals, not just to Purkinje but also to basket and stellate neurons. The well-known mossy fiber-granule cell-Golgi cell system should also respond to inputs originating from climbing fibers. Corticonuclear microcomplexing might be aided by stellate and basket computation and associate processing. Technological and scientific implications of the proposed cerebellum model are discussed.

  10. RETRACTED: Granular and intergranular conduction in La1.32Sr1.68Mn2O7 layered manganite system

    Narjis, A.; El kaaouachi, A.; Dlimi, S.; Biskupski, G.; Daoudi, E.; Errai, M.; Sybous, A.; Limouny, L.

    2013-01-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal ( (http://www.elsevier.com/locate/withdrawalpolicy)). This article has been retracted at the request of the Editors. The authors have plagiarized part of a paper that had already appeared in J. Appl. Phys. 106, 093709 (2009); (10.1063/1.3256182) (6 pages): Title: Effects of pressure on charge transport and magnetic properties of La1.32Sr1.68Mn2O7 layered manganite by M. Kumaresavanji, M. S. Reis, Y. T. Xing, and M. B. Fontes. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process

  11. Effects of Ethanol on the Cerebellum: Advances and Prospects.

    Luo, Jia

    2015-08-01

    Alcohol abuse causes cerebellar dysfunction and cerebellar ataxia is a common feature in alcoholics. Alcohol exposure during development also impacts the cerebellum. Children with fetal alcohol spectrum disorder (FASD) show many symptoms associated specifically with cerebellar deficits. However, the cellular and molecular mechanisms are unclear. This special issue discusses the most recent advances in the study of mechanisms underlying alcoholinduced cerebellar deficits. The alteration in GABAA receptor-dependent neurotransmission is a potential mechanism for ethanol-induced cerebellar dysfunction. Recent advances indicate ethanol-induced increases in GABA release are not only in Purkinje cells (PCs), but also in molecular layer interneurons and granule cells. Ethanol is shown to disrupt the molecular events at the mossy fiber - granule cell - Golgi cell (MGG) synaptic site and granule cell parallel fibers - PCs (GPP) synaptic site, which may be responsible for ethanol-induced cerebellar ataxia. Aging and ethanol may affect the smooth endoplasmic reticulum (SER) of PC dendrites and cause dendritic regression. Ethanol withdrawal causes mitochondrial damage and aberrant gene modifications in the cerebellum. The interaction between these events may result in neuronal degeneration, thereby contributing to motoric deficit. Ethanol activates doublestranded RNA (dsRNA)-activated protein kinase (PKR) and PKR activation is involved ethanolinduced neuroinflammation and neurotoxicity in the developing cerebellum. Ethanol alters the development of cerebellar circuitry following the loss of PCs, which could result in modifications of the structure and function of other brain regions that receive cerebellar inputs. Lastly, choline, an essential nutrient is evaluated for its potential protection against ethanol-induced cerebellar damages. Choline is shown to ameliorate ethanol-induced cerebellar dysfunction when given before ethanol exposure.

  12. Impact of granular drops

    Marston, J. O.

    2013-07-15

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  13. Impact of granular drops

    Marston, J. O.; Mansoor, Mohammad M.; Thoroddsen, Sigurdur T

    2013-01-01

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  14. Fracture surfaces of granular pastes.

    Mohamed Abdelhaye, Y O; Chaouche, M; Van Damme, H

    2013-11-01

    Granular pastes are dense dispersions of non-colloidal grains in a simple or a complex fluid. Typical examples are the coating, gluing or sealing mortars used in building applications. We study the cohesive rupture of thick mortar layers in a simple pulling test where the paste is initially confined between two flat surfaces. After hardening, the morphology of the fracture surfaces was investigated, using either the box counting method to analyze fracture profiles perpendicular to the mean fracture plane, or the slit-island method to analyze the islands obtained by cutting the fracture surfaces at different heights, parallel to the mean fracture plane. The fracture surfaces were shown to exhibit scaling properties over several decades. However, contrary to what has been observed in the brittle or ductile fracture of solid materials, the islands were shown to be mass fractals. This was related to the extensive plastic flow involved in the fracture process.

  15. De rijping van het cerebellum; a study of the postnatal development of the rat cerebellum.

    Ebels, E.J.

    1969-01-01

    Chapter I: INTRODUCTION In this investigation the development of the rat cerebellum from 0 -30 days after birth is studied morphologically, by means of enzymchistochemistry and electronmicroscopy. Enzymchistochemistry and electronmicroscopy were chosen because changes in enzyme content or enzyme

  16. Autism spectrum disorders and neuropathology of the cerebellum

    Hampson, David R.; Blatt, Gene J.

    2015-01-01

    The cerebellum contains the largest number of neurons and synapses of any structure in the central nervous system. The concept that the cerebellum is solely involved in fine motor function has become outdated; substantial evidence has accumulated linking the cerebellum with higher cognitive functions including language. Cerebellar deficits have been implicated in autism for more than two decades. The computational power of the cerebellum is essential for many, if not most of the processes ...

  17. Granular Cell Tumor

    1). Her packed cell volume was 40%, she was system, gastro-intestinal tract, brain, heart, and negative to human immunodeficiency virus. 2 female reproductive . ... histocytes and neurons at various times. They granules. The granules are probably of lysosmal were consequently termed granular cell origin and contain ...

  18. The effects of heavy ion particles on the developing murine cerebellum, with special reference to cell death

    Kinoshita, Chikako; Yaoi, Takeshi; Fushiki, Shinji; Nojima, Kumie

    2003-01-01

    We report here the effects of heavy ion beams on postnatal mouse cerebellar development, with reference to cell death. Eight-day-old B6C3F1 mice were irradiated with single doses of 0.1, 0.25, 0.5, 1.0, and 2.0 Gy, using a carbon beam of 290 MeV delivered from a heavy ion medical accelerator in Chiba (HIMAC). To compare the effects of X-rays with those of accelerated carbon ions, 8-day-old mice were exposed to X-rays single doses of 0.1, 0.25, 0.5, 1.0, and 2.0 Gy, respectively. Pups were fixed at 1, 6, 12 and 24 hr after exposure to HIMAC beams or X-rays. Four-μm-thick parasagittal sections of the cerebella were processed for hematoxylin-eosin staining as well as for staining with the TUNEL (terminal dUTP nick-end labeling) technique. The density of fragmented nuclei in the external granular layer increased with time, peaking at 6 hr after exposure, in both the HIMAC and X-irradiated groups. In the HIMAC groups, the density was significantly higher in those animals exposed to 0.25 Gy or more compared to 0 Gy, whereas in the X-irradiated groups it was significantly higher in those mice exposed to 0.5 Gy or more. Electron microscopic examinations revealed chromatin condensation in the cell nuclei in the HIMAC groups. This is the first in vivo evidence that apoptotic cell death is induced in developing mouse cerebellum after exposure to heavy ion particles. The difference in the frequency of dying cells between exposure to heavy ion particles and to X-rays may reflect the high linear energy transfer (LET) associated with a heavy ion beam. (author)

  19. The three layers of adaptation granularity

    Cristea, A.I.; Calvi, L.; Brusilovsky, P.; Corbett, A.; Rosis, de F.

    2003-01-01

    In spite of the interest in AHS, there are not as many applications as could be expected. We have previously pinpointed the problem to rely on the difficulty of AHS authoring. Adaptive features that have been successfully introduced and implemented until now are often too fine grained, and an author

  20. Spontaneous anaplasia in pilocytic astrocytoma of cerebellum.

    Lach, B; Al Shail, E; Patay, Z

    2003-06-01

    We report a cystic cerebellar astrocytoma with a mural nodule that contained an additional focus of astrocytoma with the histological features of anaplasia, and showed up to 48% of aneuploid and 3% S-phase cells on flow cytometry. This focus was detectable on the enhanced, as well as non-enhanced T1 and T2 images. This appears to be the first case of pilocytic astrocytoma of cerebellum with focal anaplasia detected on histological and radiological studies.

  1. Neuroimmune regulation of neurophysiology in the cerebellum.

    Gruol, Donna L

    2013-06-01

    Recent studies have established the existence of an innate immune system in the central nervous system (CNS) and implicated a critical role for this system in both normal and pathological processes. Astrocytes and microglia, normal components of the CNS, are the primary cell types that comprise the innate immune system of the CNS. Basic to their role during normal and adverse conditions is the production of neuroimmune factors such as cytokines and chemokines, which are signaling molecules that initiate or coordinate downstream cellular actions. During adverse conditions, cytokines and chemokines function in defensive and repair. However, if expression of these factors becomes dysregulated, abnormal CNS function can result. Both neurons and glial cells of the CNS express receptors for cytokines and chemokines, but the biological consequence of receptor activation has yet to be fully resolved. Our studies show that neuroadaptive changes are produced in primary cultures of rat cerebellar cells chronically treated with the cytokine interleukin-6 (IL-6) and in the cerebellum of transgenic mice that chronically express elevated levels of IL-6 in the CNS. In the cerebellum in culture and in vivo, the neuroadaptive changes included alterations in the level of expression of proteins involved in gene expression, signal transduction, and synaptic transmission. Associated with these changes were alterations in neuronal function. A comparison of results from the cultured cerebellar cells and cerebellum of the transgenic mice indicated that the effects of IL-6 can vary across neuronal types. However, alterations in mechanisms involved in Ca(2+) homeostasis were observed in all cell types studied. These results indicate that modifications in cerebellar function are likely to occur in disorders associated with elevated levels of IL-6 in the cerebellum.

  2. Maternal exposure of rats to nicotine via infusion during gestation produces neurobehavioral deficits and elevated expression of glial fibrillary acidic protein in the cerebellum and CA1 subfield in the offspring at puberty

    Abdel-Rahman, Ali; Dechkovskaia, Anjelika M.; Sutton, Jazmine M.; Chen, Wei-Chung; Guan, Xiangrong; Khan, Wasiuddin A.; Abou-Donia, Mohamed B.

    2005-01-01

    Maternal smoking during pregnancy is known to be a significant contributor to developmental neurological health problems in the offspring. In animal studies, nicotine treatment via injection during gestation has been shown to produce episodic hypoxia in the developing fetus. Nicotine delivery via mini osmotic pump, while avoiding effects due to hypoxia-ischemia, it also provides a steady level of nicotine in the plasma. In the present study timed-pregnant Sprague-Dawley rats (300-350 g) were treated with nicotine (3.3 mg/kg, in bacteriostatic water via s.c. implantation of mini osmotic pump) from gestational days (GD) 4-20. Control animals were treated with bacteriostatic water via s.c. implantation of mini osmotic pump. Offspring on postnatal day (PND) 30 and 60, were evaluated for changes in the ligand binding for various types of nicotinic acetylcholine receptors and neuropathological alterations. Neurobehavioral evaluations for sensorimotor functions, beam-walk score, beam-walk time, incline plane and grip time response were carried out on PND 60 offspring. Beam-walk time and forepaw grip time showed significant impairments in both male and female offspring. Ligand binding densities for [ 3 H]epibatidine, [ 3 H]cytisine and [ 3 H]α-bungarotoxin did not show any significant changes in nicotinic acetylcholine receptors subtypes in the cortex at PND 30 and 60. Histopathological evaluation using cresyl violet staining showed significant decrease in surviving Purkinje neurons in the cerebellum and a decrease in surviving neurons in the CA1 subfield of hippocampus on PND 30 and 60. An increase in glial fibrillary acidic protein (GFAP) immuno-staining was observed in cerebellum white matter as well as granular cell layer of cerebellum and the CA1 subfield of hippocampus on PND 30 and 60 of both male and female offspring. These results indicate that maternal exposure to nicotine produces significant neurobehavioral deficits, a decrease in the surviving neurons and an

  3. Distrofia corneal granular

    Alexeide de la C Castillo Pérez

    Full Text Available Las distrofias corneales constituyen un conjunto de enfermedades que presentan, en su mayoría, una baja incidencia y se caracterizan por acúmulo de material hialino o amiloide que disminuyen la transparencia corneal. La distrofia granular es una enfermedad autosómica dominante que presenta opacidades grises en el estroma superficial central de la córnea y se hacen visibles en la primera y segunda décadas de la vida, lo que provoca disminución de la visión más significativa cerca de los 40 años de edad. Presentamos dos casos clínicos de distrofia granular en pacientes hermanos de diferentes sexos, quienes acudieron a la consulta y refirieron visión nublada. El estudio de la historia familiar nos ayuda en el correcto diagnóstico y la biomicroscopia constituye el elemento más importante.

  4. Visuomotor cerebellum in human and nonhuman primates.

    Voogd, Jan; Schraa-Tam, Caroline K L; van der Geest, Jos N; De Zeeuw, Chris I

    2012-06-01

    In this paper, we will review the anatomical components of the visuomotor cerebellum in human and, where possible, in non-human primates and discuss their function in relation to those of extracerebellar visuomotor regions with which they are connected. The floccular lobe, the dorsal paraflocculus, the oculomotor vermis, the uvula-nodulus, and the ansiform lobule are more or less independent components of the visuomotor cerebellum that are involved in different corticocerebellar and/or brain stem olivocerebellar loops. The floccular lobe and the oculomotor vermis share different mossy fiber inputs from the brain stem; the dorsal paraflocculus and the ansiform lobule receive corticopontine mossy fibers from postrolandic visual areas and the frontal eye fields, respectively. Of the visuomotor functions of the cerebellum, the vestibulo-ocular reflex is controlled by the floccular lobe; saccadic eye movements are controlled by the oculomotor vermis and ansiform lobule, while control of smooth pursuit involves all these cerebellar visuomotor regions. Functional imaging studies in humans further emphasize cerebellar involvement in visual reflexive eye movements and are discussed.

  5. Microservices: Granularity vs. Performance

    Shadija, Dharmendra; Rezai, Mo; Hill, Richard

    2017-01-01

    Microservice Architectures (MA) have the potential to increase the agility of software development. In an era where businesses require software applications to evolve to support emerging software requirements, particularly for Internet of Things (IoT) applications, we examine the issue of microservice granularity and explore its effect upon application latency. Two approaches to microservice deployment are simulated; the first with microservices in a single container, and the second with micr...

  6. Right Lateral Cerebellum Represents Linguistic Predictability.

    Lesage, Elise; Hansen, Peter C; Miall, R Chris

    2017-06-28

    Mounting evidence indicates that posterolateral portions of the cerebellum (right Crus I/II) contribute to language processing, but the nature of this role remains unclear. Based on a well-supported theory of cerebellar motor function, which ascribes to the cerebellum a role in short-term prediction through internal modeling, we hypothesize that right cerebellar Crus I/II supports prediction of upcoming sentence content. We tested this hypothesis using event-related fMRI in male and female human subjects by manipulating the predictability of written sentences. Our design controlled for motor planning and execution, as well as for linguistic features and working memory load; it also allowed separation of the prediction interval from the presentation of the final sentence item. In addition, three further fMRI tasks captured semantic, phonological, and orthographic processing to shed light on the nature of the information processed. As hypothesized, activity in right posterolateral cerebellum correlated with the predictability of the upcoming target word. This cerebellar region also responded to prediction error during the outcome of the trial. Further, this region was engaged in phonological, but not semantic or orthographic, processing. This is the first imaging study to demonstrate a right cerebellar contribution in language comprehension independently from motor, cognitive, and linguistic confounds. These results complement our work using other methodologies showing cerebellar engagement in linguistic prediction and suggest that internal modeling of phonological representations aids language production and comprehension. SIGNIFICANCE STATEMENT The cerebellum is traditionally seen as a motor structure that allows for smooth movement by predicting upcoming signals. However, the cerebellum is also consistently implicated in nonmotor functions such as language and working memory. Using fMRI, we identify a cerebellar area that is active when words are predicted and

  7. Type-2 fuzzy granular models

    Sanchez, Mauricio A; Castro, Juan R

    2017-01-01

    In this book, a series of granular algorithms are proposed. A nature inspired granular algorithm based on Newtonian gravitational forces is proposed. A series of methods for the formation of higher-type information granules represented by Interval Type-2 Fuzzy Sets are also shown, via multiple approaches, such as Coefficient of Variation, principle of justifiable granularity, uncertainty-based information concept, and numerical evidence based. And a fuzzy granular application comparison is given as to demonstrate the differences in how uncertainty affects the performance of fuzzy information granules.

  8. Mathematical models of granular matter

    Mariano, Paolo; Giovine, Pasquale

    2008-01-01

    Granular matter displays a variety of peculiarities that distinguish it from other appearances studied in condensed matter physics and renders its overall mathematical modelling somewhat arduous. Prominent directions in the modelling granular flows are analyzed from various points of view. Foundational issues, numerical schemes and experimental results are discussed. The volume furnishes a rather complete overview of the current research trends in the mechanics of granular matter. Various chapters introduce the reader to different points of view and related techniques. New models describing granular bodies as complex bodies are presented. Results on the analysis of the inelastic Boltzmann equations are collected in different chapters. Gallavotti-Cohen symmetry is also discussed.

  9. The cerebellum and cognition: evidence from functional imaging studies.

    Stoodley, Catherine J

    2012-06-01

    Evidence for a role of the human cerebellum in cognitive functions comes from anatomical, clinical and neuroimaging data. Functional neuroimaging reveals cerebellar activation during a variety of cognitive tasks, including language, visual-spatial, executive, and working memory processes. It is important to note that overt movement is not a prerequisite for cerebellar activation: the cerebellum is engaged during conditions which either control for motor output or do not involve motor responses. Resting-state functional connectivity data reveal that, in addition to networks underlying motor control, the cerebellum is part of "cognitive" networks with prefrontal and parietal association cortices. Consistent with these findings, regional differences in activation patterns within the cerebellum are evident depending on the task demands, suggesting that the cerebellum can be broadly divided into functional regions based on the patterns of anatomical connectivity between different regions of the cerebellum and sensorimotor and association areas of the cerebral cortex. However, the distinct contribution of the cerebellum to cognitive tasks is not clear. Here, the functional neuroimaging evidence for cerebellar involvement in cognitive functions is reviewed and related to hypotheses as to why the cerebellum is active during such tasks. Identifying the precise role of the cerebellum in cognition-as well as the mechanism by which the cerebellum modulates performance during a wide range of tasks-remains a challenge for future investigations.

  10. How granular vortices can help understanding rheological and mixing properties of dense granular flows

    Rognon Pierre

    2017-01-01

    Full Text Available Dense granular flows exhibit fascinating kinematic patterns characterised by strong fluctuations in grain velocities. In this paper, we analyse these fluctuations and discuss their possible role on macroscopic properties such as effective viscosity, non-locality and shear-induced diffusion. The analysis is based on 2D experimental granular flows performed with the stadium shear device and DEM simulations. We first show that, when subjected to shear, grains self-organised into clusters rotating like rigid bodies. The average size of these so-called granular vortices is found to increase and diverge for lower inertial numbers, when flows decelerate and stop. We then discuss how such a microstructural entity and its associated internal length scale, possibly much larger than a grain, may be used to explain two important properties of dense granular flows: (i the existence of shear-induced diffusion of grains characterised by a shear-rate independent diffusivity and (ii the development of boundary layers near walls, where the viscosity is seemingly lower than the viscosity far from walls.

  11. Using a Time Granularity Table for Gradual Granular Data Aggregation

    Iftikhar, Nadeem; Pedersen, Torben Bach

    2010-01-01

    solution for data reduction based on gradual granular data aggregation. With the gradual granular data aggregation mechanism, older data can be made coarse-grained while keeping the newest data fine-grained. For instance, when data is 3 months old aggregate to 1 minute level from 1 second level, when data...... and improve query performance, especially on resource-constrained systems with limited storage and query processing capabilities. A number of data reduction solutions have been developed, however an effective solution particularly based on gradual data reduction is missing. This paper presents an effective...... is 6 months old aggregate to 2 minutes level from 1 minute level and so on. The proposed solution introduces a time granularity based data structure, namely a relational time granularity table that enables long term storage of old data by maintaining it at different levels of granularity and effective...

  12. The cerebellum for jocks and nerds alike.

    Popa, Laurentiu S; Hewitt, Angela L; Ebner, Timothy J

    2014-01-01

    Historically the cerebellum has been implicated in the control of movement. However, the cerebellum's role in non-motor functions, including cognitive and emotional processes, has also received increasing attention. Starting from the premise that the uniform architecture of the cerebellum underlies a common mode of information processing, this review examines recent electrophysiological findings on the motor signals encoded in the cerebellar cortex and then relates these signals to observations in the non-motor domain. Simple spike firing of individual Purkinje cells encodes performance errors, both predicting upcoming errors as well as providing feedback about those errors. Further, this dual temporal encoding of prediction and feedback involves a change in the sign of the simple spike modulation. Therefore, Purkinje cell simple spike firing both predicts and responds to feedback about a specific parameter, consistent with computing sensory prediction errors in which the predictions about the consequences of a motor command are compared with the feedback resulting from the motor command execution. These new findings are in contrast with the historical view that complex spikes encode errors. Evaluation of the kinematic coding in the simple spike discharge shows the same dual temporal encoding, suggesting this is a common mode of signal processing in the cerebellar cortex. Decoding analyses show the considerable accuracy of the predictions provided by Purkinje cells across a range of times. Further, individual Purkinje cells encode linearly and independently a multitude of signals, both kinematic and performance errors. Therefore, the cerebellar cortex's capacity to make associations across different sensory, motor and non-motor signals is large. The results from studying how Purkinje cells encode movement signals suggest that the cerebellar cortex circuitry can support associative learning, sequencing, working memory, and forward internal models in non

  13. Granular corneal dystrophy

    Castillo Pérez, Alexeide de la C; Vilches Lescaille, Daysi; Noriega, Justo Luis; Martínez Balido, Daneel; León Balbón, Bárbaro Ramón; León Bernal, Danysleidi

    2015-01-01

    Las distrofias corneales constituyen un conjunto de enfermedades que presentan, en su mayoría, una baja incidencia y se caracterizan por acúmulo de material hialino o amiloide que disminuyen la transparencia corneal. La distrofia granular es una enfermedad autosómica dominante que presenta opacidades grises en el estroma superficial central de la córnea y se hacen visibles en la primera y segunda décadas de la vida, lo que provoca disminución de la visión más significativa cerca de los 40 año...

  14. Sinking a Granular Raft

    Protière, Suzie; Josserand, Christophe; Aristoff, Jeffrey M.; Stone, Howard A.; Abkarian, Manouk

    2017-03-01

    We report experiments that yield new insights on the behavior of granular rafts at an oil-water interface. We show that these particle aggregates can float or sink depending on dimensionless parameters taking into account the particle densities and size and the densities of the two fluids. We characterize the raft shape and stability and propose a model to predict its shape and maximum length to remain afloat. Finally we find that wrinkles and folds appear along the raft due to compression by its own weight, which can trigger destabilization. These features are characteristics of an elastic instability, which we discuss, including the limitations of our model.

  15. Use of rubber shreds to enhance attenuation of railway sub-ballast layers made of unbound aggregates; Uso de partículas de caucho para mejorar la capacidad de atenuación de capas granulares de subbalasto en ferrocarriles

    Hidalgo-Signes, C.; Garzón-Roca, J.; Grima-Palop, J.M.; Insa-Franco, R.

    2017-07-01

    One of the approaches for solving the problem of induced vibrations in railways is by slightly modifying the materials that form the track. A study is presented of the attenuation capacity of mixes composed of granular soil and rubber shreds when used as sub-ballast (the layer located immediately below the ballast layer). Rubber shreds are obtained from scrap tyres, a troublesome waste material whose reuse and recycling is necessary. A series of mixes of granular soil and rubber shreds with rubber contents of between 1% and 10% are submitted to hammer impact tests to study their response to dynamic excitation. Results reveal that mixing rubber shreds with granular soil increases damping ratios, thus demonstrating the potential of the proposed mixes for attenuating vibration. [Spanish] Una de las posibles formas de resolver el problema de las vibraciones inducidas por el ferrocarril es llevando a cabo una ligera modificación de los materiales que forman la vía. En este artículo, se presenta un estudio de la capacidad de atenuación de mezclas compuestas por zahorras y partículas de caucho para ser usadas como sub-balasto (capa localizada bajo el balasto). Las partículas de caucho se obtienen a partir de neumáticos fuera de uso, un material problemático cuya reutilización y reciclaje es cada vez más necesario. Las mezclas de zahorra-caucho, con un contenido entre el 1% y 10%, se someten a una serie de ensayos dinámicos mediante impacto con martillo, estudiando su respuesta frente a la excitación dinámica. Los resultados revelan que la mezcla de partículas de caucho con zahorras aumenta el coeficiente de amortiguamiento, lo que muestra el potencial que poseen las mezclas propuestas para la atenuación de vibraciones.

  16. The effect of trichlorfon and methylazoxymethanol on the development of guinea pig cerebellum

    Mehl, Anna; Schanke, Tore M.; Torvik, Ansgar; Fonnum, Frode

    2007-01-01

    The pesticide trichlorfon (125 mg/kg on days 42-44 in gestation) gives hypoplasia of Brain of the offspring without any significant reduction in their body weights. The hypoplasia may be caused by trichlorfon itself or by its metabolite dichlorvos. This period of development coincides with the growth spurt period of guinea pig brain. The largest changes occurred in the cerebellum. Electron microscopic examination of the cerebellar cortex showed increased apoptotic death of cells in the granule cell layer after trichlorfon treatment. A reduction in thickness of the external germinal layer of the cerebellar cortex and an elevated amount of pyknotic and karyorrhexic cells in the granule cell layer was found. There was a significant reduction in choline esterase, choline acetyltransferase and glutamate decarboxylase activities in the cerebellum. Methylazoxymethanol (15 mg/kg body weight, day 43) was examined for comparison and caused similar hypoplasia of the guinea pig cerebellum, but did also induce a reduction in body weight. Trichloroethanol, the main metabolite of trichlorfon, did not give brain hypoplasia

  17. Functionally heterogenous ryanodine receptors in avian cerebellum.

    Sierralta, J; Fill, M; Suárez-Isla, B A

    1996-07-19

    The functional heterogeneity of the ryanodine receptor (RyR) channels in avian cerebellum was defined. Heavy endoplasmic reticulum microsomes had significant levels of ryanodine and inositol 1,4,5-trisphosphate binding. Scatchard analysis and kinetic studies indicated the existence of at least two distinct ryanodine binding sites. Ryanodine binding was calcium-dependent but was not significantly enhanced by caffeine. Incorporation of microsomes into planar lipid bilayers revealed ion channels with pharmacological features (calcium, magnesium, ATP, and caffeine sensitivity) similar to the RyR channels found in mammalian striated muscle. Despite a wide range of unitary conductances (220-500 picosiemens, symmetrical cesium methanesulfonate), ryanodine locked both channels into a characteristic slow gating subconductance state, positively identifying them as RyR channels. Two populations of avian RyR channels were functionally distinguished by single channel calcium sensitivity. One population was defined by a bell-shaped calcium sensitivity analogous to the skeletal muscle RyR isoform (type I). The calcium sensitivity of the second RyR population was sigmoidal and analogous to the cardiac muscle RyR isoform (type II). These data show that there are at least two functionally distinct RyR channel populations in avian cerebellum. This leads to the possibility that these functionally distinct RyR channels are involved in different intracellular calcium signaling pathways.

  18. The Cerebellum and Premenstrual Dysphoric Disorder.

    Rapkin, Andrea J; Berman, Steven M; London, Edythe D

    2014-01-01

    The cerebellum constitutes ten percent of brain volume and contains the majority of brain neurons. Although it was historically viewed primarily as processing motoric computations, current evidence supports a more comprehensive role, where cerebro-cerebellar feedback loops also modulate various forms of cognitive and affective processing. Here we present evidence for a role of the cerebellum in premenstrual dysphoric disorder (PMDD), which is characterized by severe negative mood symptoms during the luteal phase of the menstrual cycle. Although a link between menstruation and cyclical dysphoria has long been recognized, neuroscientific investigations of this common disorder have only recently been explored. This article reviews functional and structural brain imaging studies of PMDD and the similar but less well defined condition of premenstrual syndrome (PMS). The most consistent findings are that women with premenstrual dysphoria exhibit greater relative activity than other women in the dorsolateral prefrontal cortex and posterior lobules VI and VII of the neocerebellum. Since both brain areas have been implicated in emotional processing and mood disorders, working memory and executive functions, this greater activity probably represents coactivation within a cerebro-cerebellar feedback loop regulating emotional and cognitive processing. Some of the evidence suggests that increased activity within this circuit may preserve cerebellar structure during aging, and possible mechanisms and implications of this finding are discussed.

  19. The cerebellum and decision making under uncertainty.

    Blackwood, Nigel; Ffytche, Dominic; Simmons, Andrew; Bentall, Richard; Murray, Robin; Howard, Robert

    2004-06-01

    This study aimed to identify the neural basis of probabilistic reasoning, a type of inductive inference that aids decision making under conditions of uncertainty. Eight normal subjects performed two separate two-alternative-choice tasks (the balls in a bottle and personality survey tasks) while undergoing functional magnetic resonance imaging (fMRI). The experimental conditions within each task were chosen so that they differed only in their requirement to make a decision under conditions of uncertainty (probabilistic reasoning and frequency determination required) or under conditions of certainty (frequency determination required). The same visual stimuli and motor responses were used in the experimental conditions. We provide evidence that the neo-cerebellum, in conjunction with the premotor cortex, inferior parietal lobule and medial occipital cortex, mediates the probabilistic inferences that guide decision making under uncertainty. We hypothesise that the neo-cerebellum constructs internal working models of uncertain events in the external world, and that such probabilistic models subserve the predictive capacity central to induction. Copyright 2004 Elsevier B.V.

  20. Friction dependence of shallow granular flows from discrete particle simulations

    Thornton, Anthony Richard; Weinhart, Thomas; Luding, Stefan; Bokhove, Onno

    2011-01-01

    A shallow-layer model for granular flows is completed with a closure relation for the macroscopic bed friction or basal roughness obtained from micro-scale discrete particle simulations of steady flows. We systematically vary the bed friction by changing the contact friction coefficient between

  1. Large granular lymphocyte leukemia

    Terra, Bruno; Maia, Amanda M.

    2010-01-01

    O presente estudo tem como objetivo o estabelecimento de fundamentação teórica atualizada baseada em revisão bibliográfica sobre a leucemia de grandes linfócitos granulares (LGLG), doença onco-hematológica, que, devido à sua relativa raridade, é pouco conhecida e subdiagnosticada. A LGLG é caracterizada pela proliferação clonal de linfócitos T ou NK na medula óssea e/ou no sangue periférico. Dentre as manifestações clínico-laboratoriais, podem ocorrer citopenias (anemia e/ou neutropenia e/ou ...

  2. Morphometric Studies Of The Cerebellum And Forebrain Of The ...

    Morphometric studies were undertaken using the brains of six African giant rats. The mean of weights and lengths (tip of the olfactory bulb to the caudal border of the cerebellum) were observed tobe 4.88 0.183g and 4.40 0.193g, respectively. Similarly, the mean weight and length of the cerebellum and the forebrain ...

  3. Multiple sclerosis impairs regional functional connectivity in the cerebellum

    Dogonowski, Anne-Marie; Andersen, Kasper Winther; Madsen, Kristoffer Hougaard

    2013-01-01

    in the cerebellum in MS. This might be caused by a functional disruption of cortico-ponto-cerebellar and spino-cerebellar inputs, since patients with higher lesion load in the left cerebellar peduncles showed a stronger reduction in cerebellar homogeneity. In patients, two clusters in the left posterior cerebellum...

  4. Consensus Paper: The Cerebellum's Role in Movement and Cognition

    Koziol, Leonard F.; Budding, Deborah; Andreasen, Nancy; D'Arrigo, Stefano; Bulgheroni, Sara; Imamizu, Hiroshi; Ito, Masao; Manto, Mario; Marvel, Cherie; Parker, Krystal; Pezzulo, Giovanni; Ramnani, Narender; Riva, Daria; Schmahmann, Jeremy; Vandervert, Larry; Yamazaki, Tadashi

    2014-01-01

    While the cerebellum's role in motor function is well recognized, the nature of its concurrent role in cognitive function remains considerably less clear. The current consensus paper gathers diverse views on a variety of important roles played by the cerebellum across a range of cognitive and emotional functions. This paper considers the cerebellum in relation to neurocognitive development, language function, working memory, executive function, and the development of cerebellar internal control models and reflects upon some of the ways in which better understanding the cerebellum's status as a “supervised learning machine” can enrich our ability to understand human function and adaptation. As all contributors agree that the cerebellum plays a role in cognition, there is also an agreement that this conclusion remains highly inferential. Many conclusions about the role of the cerebellum in cognition originate from applying known information about cerebellar contributions to the coordination and quality of movement. These inferences are based on the uniformity of the cerebellum's compositional infrastructure and its apparent modular organization. There is considerable support for this view, based upon observations of patients with pathology within the cerebellum. PMID:23996631

  5. Role of cerebellum in deglutition and deglutition disorders.

    Rangarathnam, Balaji; Kamarunas, Erin; McCullough, Gary H

    2014-12-01

    The objective of this review is to gather available evidence regarding the role of the cerebellum in swallowing-related functions. We reviewed literature on cerebellar functions related to healthy swallowing, patterns of dysphagia in individuals with cerebellar lesions, and the role of the cerebellum in therapeutic intervention of neurogenic dysphagia since 1980. A collective understanding of these studies suggests that both hemispheres of the cerebellum, predominantly the left, participate in healthy swallowing. Also, it appears that the cerebellum contributes to specific physiological functions within the entire act of swallowing, but this is not clearly understood. The understanding of patterns of dysphagia in cerebellar lesions remains ambiguous with equivocal results across a small number of studies. The cerebellum appears to be involved in oral exercises for dysphagia in the relationship between oral movements in such exercises, and deglutition remains uncertain. There is increasing evidence to suggest successful use of transcranial magnetic stimulation of the cerebellum to improve neuromotor control of swallowing. Future studies should address activation of the cerebellum with swallowing of different consistencies and tastes in healthy adults to gain better insights. Studies should also investigate dynamics of neural activation during different stages of recovery from dysphagia following strokes to cortical centers to determine if the cerebellum plays a compensatory role during instances of increased neural demands.

  6. How the cerebellum may monitor sensory information for spatial representation

    Rondi-Reig, Laure; Paradis, Anne-Lise; Lefort, Julie M.; Babayan, Benedicte M.; Tobin, Christine

    2014-01-01

    The cerebellum has already been shown to participate in the navigation function. We propose here that this structure is involved in maintaining a sense of direction and location during self-motion by monitoring sensory information and interacting with navigation circuits to update the mental representation of space. To better understand the processing performed by the cerebellum in the navigation function, we have reviewed: the anatomical pathways that convey self-motion information to the cerebellum; the computational algorithm(s) thought to be performed by the cerebellum from these multi-source inputs; the cerebellar outputs directed toward navigation circuits and the influence of self-motion information on space-modulated cells receiving cerebellar outputs. This review highlights that the cerebellum is adequately wired to combine the diversity of sensory signals to be monitored during self-motion and fuel the navigation circuits. The direct anatomical projections of the cerebellum toward the head-direction cell system and the parietal cortex make those structures possible relays of the cerebellum influence on the hippocampal spatial map. We describe computational models of the cerebellar function showing that the cerebellum can filter out the components of the sensory signals that are predictable, and provides a novelty output. We finally speculate that this novelty output is taken into account by the navigation structures, which implement an update over time of position and stabilize perception during navigation. PMID:25408638

  7. Thermal conductivity of granular materials

    Buyevich, Yu A

    1974-01-01

    Stationary heat transfer in a granular material consisting of a continuous medium containing spherical granules of other substances is considered under the assumption that the spatial distribution of granules is random. The effective thermal conductivity characterizing macroscopic heat transfer in such a material is expressed as a certain function of the conductivities and volume fractions of the medium and dispersed substances. For reasons of mathematical analogy, all the results obtained for the thermal conductivity are valid while computing the effective diffusivity of some admixture in granular materials as well as for evaluation of the effective electric conductivity or the mean dielectric and magnetic permeabilities of granular conductors and dielectrics. (23 refs.)

  8. The cerebellum: a neuronal learning machine?

    Raymond, J. L.; Lisberger, S. G.; Mauk, M. D.

    1996-01-01

    Comparison of two seemingly quite different behaviors yields a surprisingly consistent picture of the role of the cerebellum in motor learning. Behavioral and physiological data about classical conditioning of the eyelid response and motor learning in the vestibulo-ocular reflex suggests that (i) plasticity is distributed between the cerebellar cortex and the deep cerebellar nuclei; (ii) the cerebellar cortex plays a special role in learning the timing of movement; and (iii) the cerebellar cortex guides learning in the deep nuclei, which may allow learning to be transferred from the cortex to the deep nuclei. Because many of the similarities in the data from the two systems typify general features of cerebellar organization, the cerebellar mechanisms of learning in these two systems may represent principles that apply to many motor systems.

  9. Near-Infrared Confocal Laser Reflectance Cytoarchitectural Imaging of the Substantia Nigra and Cerebellum in the Fresh Human Cadaver.

    Cheyuo, Cletus; Grand, Walter; Balos, Lucia L

    2017-01-01

    Cytoarchitectural neuroimaging remains critical for diagnosis of many brain diseases. Fluorescent dye-enhanced, near-infrared confocal in situ cellular imaging of the brain has been reported. However, impermeability of the blood-brain barrier to most fluorescent dyes limits clinical utility of this modality. The differential degree of reflectance from brain tissue with unenhanced near-infrared imaging may represent an alternative technique for in situ cytoarchitectural neuroimaging. We assessed the utility of unenhanced near-infrared confocal laser reflectance imaging of the cytoarchitecture of the cerebellum and substantia nigra in 2 fresh human cadaver brains using a confocal near-infrared laser probe. Cellular images based on near-infrared differential reflectance were captured at depths of 20-180 μm from the brain surface. Parts of the cerebellum and substantia nigra imaged using the probe were subsequently excised and stained with hematoxylin and eosin for histologic correlation. Near-infrared reflectance imaging revealed the 3-layered cytoarchitecture of the cerebellum, with Purkinje cells appearing hyperreflectant. In the substantia nigra, neurons appeared hyporeflectant with hyperreflectant neuromelanin cytoplasmic inclusions. Cytoarchitecture of the cerebellum and substantia nigra revealed on near-infrared imaging closely correlated with the histology on hematoxylin-eosin staining. We showed that unenhanced near-infrared reflectance imaging of fresh human cadaver brain can reliably identify and distinguish neurons and detailed cytoarchitecture of the cerebellum and substantia nigra. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Functional imaging and the cerebellum: recent developments and challenges. Editorial.

    Habas, Christophe

    2012-06-01

    Recent neuroimaging developments allow a better in vivo characterization of the structural and functional connectivity of the human cerebellum. Ultrahigh fields, which considerably increase spatial resolution, enable to visualize deep cerebellar nuclei and cerebello-cortical sublayers. Tractography reconstructs afferent and efferent pathway of the cerebellum. Resting-state functional connectivity individualizes the prewired, parallel close-looped sensorimotor, cognitive, and affective networks passing through the cerebellum. These results are un agreement with activation maps obtained during stimulation functional neuroimaging or inferred from neurological deficits due to cerebellar lesions. Therefore, neuroimaging supports the hypothesis that cerebellum constitutes a general modulator involved in optimizing mental performance and computing internal models. However, the great challenges will remain to unravel: (1) the functional role of red and bulbar olivary nuclei, (2) the information processing in the cerebellar microcircuitry, and (3) the abstract computation performed by the cerebellum and shared by sensorimotor, cognitive, and affective domains.

  11. The cerebellum for jocks and nerds alike

    Laurentiu ePopa

    2014-06-01

    Full Text Available Historically the cerebellum has been implicated in the control of movement. However, the cerebellum’s role in non-motor functions, including cognitive and emotional processes, has also received increasing attention. Starting from the premise that the uniform architecture of the cerebellum underlies a common mode of information processing, this review examines recent electrophysiological findings on the motor signals encoded in the cerebellar cortex and then relates these signals to observations in the non-motor domain. Simple spike firing of individual Purkinje cells encodes performance errors, both predicting upcoming errors as well as providing feedback about those errors. Further, this dual temporal encoding of prediction and feedback involves a change in the sign of the simple spike modulation. Therefore, Purkinje cell simple spike firing both predicts and responds to feedback about a specific parameter, consistent with computing sensory prediction errors in which the predictions about the consequences of a motor command are compared with the feedback resulting from the motor command execution. These new findings are in contrast with the historical view that complex spikes encode errors. Evaluation of the kinematic coding in the simple spike discharge shows the same dual temporal encoding, suggesting this is a common mode of signal processing in the cerebellar cortex. Decoding analyses show the considerable accuracy of the predictions provided by Purkinje cells across a range of times. Further, individual Purkinje cells encode linearly and independently a multitude of signals, both kinematic and performance errors. Therefore, the cerebellar cortex’s capacity to make associations across different sensory, motor and non-motor signals is large. The results from studying how Purkinje cells encode movement signals suggest that the cerebellar cortex circuitry can support associative learning, sequencing, working memory, and forward internal

  12. Disinfection of bacteria attached to granular activated carbon.

    LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

    1984-01-01

    Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

  13. Granular flows: fundamentals and applications

    Cleary, Paul W.

    DEM allows the prediction of complex industrial and geophysical particle flows. The importance of particle shape is demonstrated through a series of simple examples. Shape controls resistance to shear, the magnitude of collision stress, dilation and the angle of repose. We use a periodic flow of a bed of particles to demonstrate the different states of granular matter, the generation of dilute granular flow when granular temperature is high and the flow dependent nature of the granular thermodynamic boundary conditions. A series of industrial case studies examines how DEM can be used to understand and improve processes such as separation, mixing, grinding, excavation, hopper discharge, metering and conveyor interchange. Finally, an example of landslide motion over real topography is presented.

  14. Superconductivity in inhomogeneous granular metals

    McLean, W.L.

    1980-01-01

    A model of elongated metal ellipsoids imbedded in a granular metal is treated by an effective medium approach to explain the observed temperature dependence of the normal-state conductivity of superconducting granular aluminum. Josephson tunneling is thus still required to account for the superconductivity. The model predicts the same kind of contrasting behavior on opposite sides of the metal-insulator transition as is found in the recent scaling treatment of Anderson localization

  15. Grain scale observations of stick-slip dynamics in fluid saturated granular fault gouge

    Johnson, P. A.; Dorostkar, O.; Guyer, R. A.; Marone, C.; Carmeliet, J.

    2017-12-01

    We are studying granular mechanics during slip. In the present work, we conduct coupled computational fluid dynamics (CFD) and discrete element method (DEM) simulations to study grain scale characteristics of slip instabilities in fluid saturated granular fault gouge. The granular sample is confined with constant normal load (10 MPa), and sheared with constant velocity (0.6 mm/s). This loading configuration is chosen to promote stick-slip dynamics, based on a phase-space study. Fluid is introduced in the beginning of stick phase and characteristics of slip events i.e. macroscopic friction coefficient, kinetic energy and layer thickness are monitored. At the grain scale, we monitor particle coordination number, fluid-particle interaction forces as well as particle and fluid kinetic energy. Our observations show that presence of fluids in a drained granular fault gouge stabilizes the layer in the stick phase and increases the recurrence time. In saturated model, we observe that average particle coordination number reaches higher values compared to dry granular gouge. Upon slip, we observe that a larger portion of the granular sample is mobilized in saturated gouge compared to dry system. We also observe that regions with high particle kinetic energy are correlated with zones of high fluid motion. Our observations highlight that spatiotemporal profile of fluid dynamic pressure affects the characteristics of slip instabilities, increasing macroscopic friction coefficient drop, kinetic energy release and granular layer compaction. We show that numerical simulations help characterize the micromechanics of fault mechanics.

  16. Linking Essential Tremor to the Cerebellum: Neurochemical Evidence.

    Marin-Lahoz, Juan; Gironell, Alexandre

    2016-06-01

    The pathophysiology and the exact anatomy of essential tremor (ET) is not well known. One of the pillars that support the cerebellum as the main anatomical locus in ET is neurochemistry. This review examines the link between neurochemical abnormalities found in ET and cerebellum. The review is based on published data about neurochemical abnormalities described in ET both in human and in animal studies. We try to link those findings with cerebellum. γ-aminobutyric acid (GABA) is the main neurotransmitter involved in the pathophysiology of ET. There are several studies about GABA that clearly points to a main role of the cerebellum. There are few data about other neurochemical abnormalities in ET. These include studies with noradrenaline, glutamate, adenosine, proteins, and T-type calcium channels. One single study reveals high levels of noradrenaline in the cerebellar cortex. Another study about serotonin neurotransmitter results negative for cerebellum involvement. Finally, studies on T-type calcium channels yield positive results linking the rhythmicity of ET and cerebellum. Neurochemistry supports the cerebellum as the main anatomical locus in ET. The main neurotransmitter involved is GABA, and the GABA hypothesis remains the most robust pathophysiological theory of ET to date. However, this hypothesis does not rule out other mechanisms and may be seen as the main scaffold to support findings in other systems. We clearly need to perform more studies about neurochemistry in ET to better understand the relations among the diverse systems implied in ET. This is mandatory to develop more effective pharmacological therapies.

  17. Granular Superconductors and Gravity

    Noever, David; Koczor, Ron

    1999-01-01

    As a Bose condensate, superconductors provide novel conditions for revisiting previously proposed couplings between electromagnetism and gravity. Strong variations in Cooper pair density, large conductivity and low magnetic permeability define superconductive and degenerate condensates without the traditional density limits imposed by the Fermi energy (approx. 10(exp -6) g cu cm). Recent experiments have reported anomalous weight loss for a test mass suspended above a rotating Type II, YBCO superconductor, with a relatively high percentage change (0.05-2.1%) independent of the test mass' chemical composition and diamagnetic properties. A variation of 5 parts per 104 was reported above a stationary (non-rotating) superconductor. In experiments using a sensitive gravimeter, bulk YBCO superconductors were stably levitated in a DC magnetic field and exposed without levitation to low-field strength AC magnetic fields. Changes in observed gravity signals were measured to be less than 2 parts in 108 of the normal gravitational acceleration. Given the high sensitivity of the test, future work will examine variants on the basic magnetic behavior of granular superconductors, with particular focus on quantifying their proposed importance to gravity.

  18. The Effect of Spaceflight on the Ultrastructure of the Cerebellum

    Holstein, Gay R.; Martinelli, Giorgio P.

    2003-01-01

    In weightlessness, astronauts and cosmonauts may experience postural illusions as well as motion sickness symptoms known as the space adaptation syndrome. Upon return to Earth, they have irregularities in posture and balance. The adaptation to microgravity and subsequent re-adaptation to Earth occurs over several days. At the cellular level, a process called neuronal plasticity may mediate this adaptation. The term plasticity refers to the flexibility and modifiability in the architecture and functions of the nervous system. In fact, plastic changes are thought to underlie not just behavioral adaptation, but also the more generalized phenomena of learning and memory. The goal of this experiment was to identify some of the structural alterations that occur in the rat brain during the sensory and motor adaptation to microgravity. One brain region where plasticity has been studied extensively is the cerebellar cortex-a structure thought to be critical for motor control, coordination, the timing of movements, and, most relevant to the present experiment, motor learning. Also, there are direct as well as indirect connections between projections from the gravity-sensing otolith organs and several subregions of the cerebellum. We tested the hypothesis that alterations in the ultrastructural (the structure within the cell) architecture of rat cerebellar cortex occur during the early period of adaptation to microgravity, as the cerebellum adapts to the absence of the usual gravitational inputs. The results show ultrastructural evidence for neuronal plasticity in the central nervous system of adult rats after 24 hours of spaceflight. Qualitative studies conducted on tissue from the cerebellar cortex (specifically, the nodulus of the cerebellum) indicate that ultrastructural signs of plasticity are present in the cerebellar zones that receive input from the gravity-sensing organs in the inner ear (the otoliths). These changes are not observed in this region in cagematched

  19. Blurring the boundary between rapid granular flow and dense granular flow regimes: Evidence from DEM simulations

    Tripathi, Anurag; Prasad, Mahesh; Kumar, Puneet

    2017-11-01

    The saturation of the effective friction coefficient for granular flows at high inertial numbers has been assumed widely by researchers, despite little simulation/experimental evidence. In contrast, a recent simulation study of plane shear flows by Mandal and Khakhar, suggests that the effective friction coefficient becomes maximum and then starts to decrease with increase in the inertial number for I > 0.5 . In order to investigate whether such a dip at higher inertial numbers is indeed a feature of granular rheology, we perform DEM simulations of chute flow of highly inelastic disks. We show that steady, fully developed flows are possible at inclinations much higher than those normally reported in literature. At such high inclinations, the flow is characterised by a significant slip at the base; the height of the layer increases by more than 300 % and kinetic energy of the layer increases by nearly 5 orders of magnitude. We observe, for the first time, steady chute flows at inertial number I 2 and show that the dip at higher inertial numbers can be observed in case of chute flow as well. The predictions of modified μ - I rheology, however, seem to remain valid in the bulk of the layer for packing fractions as low as 0.2. AT acknowledges the funding obtained from IIT Kanpur through the initiation Grant for this study.

  20. Active Inference and Learning in the Cerebellum.

    Friston, Karl; Herreros, Ivan

    2016-09-01

    This letter offers a computational account of Pavlovian conditioning in the cerebellum based on active inference and predictive coding. Using eyeblink conditioning as a canonical paradigm, we formulate a minimal generative model that can account for spontaneous blinking, startle responses, and (delay or trace) conditioning. We then establish the face validity of the model using simulated responses to unconditioned and conditioned stimuli to reproduce the sorts of behavior that are observed empirically. The scheme's anatomical validity is then addressed by associating variables in the predictive coding scheme with nuclei and neuronal populations to match the (extrinsic and intrinsic) connectivity of the cerebellar (eyeblink conditioning) system. Finally, we try to establish predictive validity by reproducing selective failures of delay conditioning, trace conditioning, and extinction using (simulated and reversible) focal lesions. Although rather metaphorical, the ensuing scheme can account for a remarkable range of anatomical and neurophysiological aspects of cerebellar circuitry-and the specificity of lesion-deficit mappings that have been established experimentally. From a computational perspective, this work shows how conditioning or learning can be formulated in terms of minimizing variational free energy (or maximizing Bayesian model evidence) using exactly the same principles that underlie predictive coding in perception.

  1. The cerebellum on the rise in human emotion

    Schutter, D.J.L.G.; Honk, J. van

    2005-01-01

    For decennia the cerebellum has largely been excluded from scientific enquiry beyond motor function. However, the intimate afferent and efferent connections to the midbrain and limbic system provide for the neuroanatomical foundation of cerebellar involvement in emotion and emotional disorders.

  2. Prefrontal control of cerebellum-dependent associative motor learning.

    Chen, Hao; Yang, Li; Xu, Yan; Wu, Guang-yan; Yao, Juan; Zhang, Jun; Zhu, Zhi-ru; Hu, Zhi-an; Sui, Jian-feng; Hu, Bo

    2014-02-01

    Behavioral studies have demonstrated that both medial prefrontal cortex (mPFC) and cerebellum play critical roles in trace eyeblink conditioning. However, little is known regarding the mechanism by which the two brain regions interact. By use of electrical stimulation of the caudal mPFC as a conditioned stimulus, we show evidence that persistent outputs from the mPFC to cerebellum are necessary and sufficient for the acquisition and expression of a trace conditioned response (CR)-like response. Specifically, the persistent outputs of caudal mPFC are relayed to the cerebellum via the rostral part of lateral pontine nuclei. Moreover, interfering with persistent activity by blockade of the muscarinic Ach receptor in the caudal mPFC impairs the expression of learned trace CRs. These results suggest an important way for the caudal mPFC to interact with the cerebellum during associative motor learning.

  3. Boundary effects in a quasi-two-dimensional driven granular fluid.

    Smith, N D; Smith, M I

    2017-12-01

    The effect of a confining boundary on the spatial variations in granular temperature of a driven quasi-two-dimensional layer of particles is investigated experimentally. The radial drop in the relative granular temperature ΔT/T exhibits a maximum at intermediate particle numbers which coincides with a crossover from kinetic to collisional transport of energy. It is also found that at low particle numbers, the distributions of radial velocities are increasingly asymmetric as one approaches the boundary. The radial and tangential granular temperatures split, and in the tails of the radial velocity distribution there is a higher population of fast moving particles traveling away rather than towards the boundary.

  4. Autism spectrum disorders and neuropathology of the cerebellum.

    Hampson, David R; Blatt, Gene J

    2015-01-01

    The cerebellum contains the largest number of neurons and synapses of any structure in the central nervous system. The concept that the cerebellum is solely involved in fine motor function has become outdated; substantial evidence has accumulated linking the cerebellum with higher cognitive functions including language. Cerebellar deficits have been implicated in autism for more than two decades. The computational power of the cerebellum is essential for many, if not most of the processes that are perturbed in autism including language and communication, social interactions, stereotyped behavior, motor activity and motor coordination, and higher cognitive functions. The link between autism and cerebellar dysfunction should not be surprising to those who study its cellular, physiological, and functional properties. Postmortem studies have revealed neuropathological abnormalities in cerebellar cellular architecture while studies on mouse lines with cell loss or mutations in single genes restricted to cerebellar Purkinje cells have also strongly implicated this brain structure in contributing to the autistic phenotype. This connection has been further substantiated by studies investigating brain damage in humans restricted to the cerebellum. In this review, we summarize advances in research on idiopathic autism and three genetic forms of autism that highlight the key roles that the cerebellum plays in this spectrum of neurodevelopmental disorders.

  5. Autism Spectrum Disorders and Neuropathology of the Cerebellum

    David R Hampson

    2015-11-01

    Full Text Available The cerebellum contains the largest number of neurons and synapses of any structure in the central nervous system. The concept that the cerebellum is solely involved in fine motor function has become outdated; substantial evidence has accumulated linking the cerebellum with higher cognitive functions including language. Cerebellar deficits have been implicated in autism for more than two decades. The computational power of the cerebellum is essential for many, if not most of the processes that are perturbed in autism including language and communication, social interactions, stereotyped behavior, motor activity and motor coordination, and higher cognitive functions. The link between autism and cerebellar dysfunction should not be surprising to those who study its cellular, physiological, and functional properties. Postmortem studies have revealed neuropathological abnormalities in cerebellar cellular architecture while studies on mouse lines with cell loss or mutations in single genes restricted to cerebellar Purkinje cells have also strongly implicated this brain structure in contributing to the autistic phenotype. This connection has been further substantiated by studies investigating brain damage in humans restricted to the cerebellum. In this review, we summarize advances in research on idiopathic autism and three genetic forms of autism that highlight the key roles that the cerebellum plays in this spectrum of neurodevelopmental disorders.

  6. Why granular media are thermal after all

    Liu, Mario; Jiang, Yimin

    2017-06-01

    Two approaches exist to account for granular behavior. The thermal one considers the total entropy, which includes microscopic degrees of freedom such as phonons; the athermal one (as with the Edward entropy) takes grains as elementary. Granular solid hydrodynamics (GSH) belongs to the first, DEM, granular kinetic theory and athermal statistical mechanics (ASM) to the second. A careful discussion of their conceptual differences is given here. Three noteworthy insights or results are: (1) While DEM and granular kinetic theory are well justified to take grains as elementary, any athermal entropic consideration is bound to run into trouble. (2) Many general principles are taken as invalid in granular media. Yet within the thermal approach, energy conservation and fluctuation-dissipation theorem remain valid, granular temperatures equilibrate, and phase space is well explored in a grain at rest. Hence these are abnormalities of the athermal approximation, not of granular media as such. (3) GSH is a wide-ranged continuum mechanical description of granular dynamics.

  7. Chronic lithium treatment with or without haloperidol fails to affect the morphology of the rat cerebellum

    Licht, R W; Larsen, Jytte Overgaard; Smith, D

    2003-01-01

    We used unbiased stereological principles to determine whether long-term administration of lithium at human therapeutic levels, with or without haloperidol, affects the number or sizes of cerebellar Purkinje cells or the volume of histological layers in the rat cerebellum. Twenty-eight rats were...... randomly divided into three groups, receiving either no treatment, lithium, or lithium combined with haloperidol. The serum lithium levels ranged from 0.50 to 0.77 mmol/l. Haloperidol was given at a daily dose of 1 mg/kg. After 30 weeks of treatment, the animals were killed and the cerebelli were...

  8. Electromagnetic response of a highly granular hadronic calorimeter

    Adloff, C.; Blaha, J.; Blaising, J.J. [Savoie Univ., CNRS/IN2P3, Annecy-le-Vieux (FR). Lab. d' Annecy-le-Vieux de Physique des Particules] (and others)

    2010-12-15

    The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the hadronic calorimeter, one option is a highly granular sampling calorimeter with steel as absorber and scintillator layers as active material. High granularity is obtained by segmenting the scintillator into small tiles individually read out via silicon photo-multipliers (SiPM). A prototype has been built, consisting of thirty-eight sensitive layers, segmented into about eight thousand channels. In 2007 the prototype was exposed to positrons and hadrons using the CERN SPS beam, covering a wide range of beam energies and incidence angles. The challenge of cell equalization and calibration of such a large number of channels is best validated using electromagnetic processes. The response of the prototype steel-scintillator calorimeter, including linearity and uniformity, to electrons is investigated and described. (orig.)

  9. Electromagnetic response of a highly granular hadronic calorimeter

    Adloff, C.; Blaha, J.; Blaising, J.J.

    2010-12-01

    The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the hadronic calorimeter, one option is a highly granular sampling calorimeter with steel as absorber and scintillator layers as active material. High granularity is obtained by segmenting the scintillator into small tiles individually read out via silicon photo-multipliers (SiPM). A prototype has been built, consisting of thirty-eight sensitive layers, segmented into about eight thousand channels. In 2007 the prototype was exposed to positrons and hadrons using the CERN SPS beam, covering a wide range of beam energies and incidence angles. The challenge of cell equalization and calibration of such a large number of channels is best validated using electromagnetic processes. The response of the prototype steel-scintillator calorimeter, including linearity and uniformity, to electrons is investigated and described. (orig.)

  10. Traffic and Granular Flow '11

    Buslaev, Alexander; Bugaev, Alexander; Yashina, Marina; Schadschneider, Andreas; Schreckenberg, Michael; TGF11

    2013-01-01

    This book continues the biannual series of conference proceedings, which has become a classical reference resource in traffic and granular research alike. It addresses new developments at the interface between physics, engineering and computational science. Complex systems, where many simple agents, be they vehicles or particles, give rise to surprising and fascinating phenomena.   The contributions collected in these proceedings cover several research fields, all of which deal with transport. Topics include highway, pedestrian and internet traffic, granular matter, biological transport, transport networks, data acquisition, data analysis and technological applications. Different perspectives, i.e. modeling, simulations, experiments and phenomenological observations, are considered.

  11. The cerebellum after trauma: Resting-state functional connectivity of the cerebellum in posttraumatic stress disorder and its dissociative subtype.

    Rabellino, Daniela; Densmore, Maria; Théberge, Jean; McKinnon, Margaret C; Lanius, Ruth A

    2018-04-17

    The cerebellum plays a key role not only in motor function but also in affect and cognition. Although several psychopathological disorders have been associated with overall cerebellar dysfunction, it remains unclear whether different regions of the cerebellum contribute uniquely to psychopathology. Accordingly, we compared seed-based resting-state functional connectivity of the anterior cerebellum (lobule IV-V), of the posterior cerebellum (Crus I), and of the anterior vermis across posttraumatic stress disorder (PTSD; n = 65), its dissociative subtype (PTSD + DS; n = 37), and non-trauma-exposed healthy controls (HC; n = 47). Here, we observed decreased functional connectivity of the anterior cerebellum and anterior vermis with brain regions involved in somatosensory processing, multisensory integration, and bodily self-consciousness (temporo-parietal junction, postcentral gyrus, and superior parietal lobule) in PTSD + DS as compared to PTSD and HC. Moreover, the PTSD + DS group showed increased functional connectivity of the posterior cerebellum with cortical areas related to emotion regulation (ventromedial prefrontal and orbito-frontal cortex, subgenual anterior cingulum) as compared to PTSD. By contrast, PTSD showed increased functional connectivity of the anterior cerebellum with cortical areas associated with visual processing (fusiform gyrus), interoceptive awareness (posterior insula), memory retrieval, and contextual processing (hippocampus) as compared to HC. Finally, we observed decreased functional connectivity between the posterior cerebellum and prefrontal regions involved in emotion regulation, in PTSD as compared to HC. These findings not only highlight the crucial role of each cerebellar region examined in the psychopathology of PTSD but also reveal unique alterations in functional connectivity distinguishing the dissociative subtype of PTSD versus PTSD. © 2018 Wiley Periodicals, Inc.

  12. Uniform shock waves in disordered granular matter

    Gómez, L.R.; Turner, A.M.; Vitelli, V.

    2012-01-01

    The confining pressure P is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates

  13. Stretched exponentials and power laws in granular avalanching

    Head, D. A.; Rodgers, G. J.

    1999-02-01

    We introduce a model for granular surface flow which exhibits both stretched exponential and power law avalanching over its parameter range. Two modes of transport are incorporated, a rolling layer consisting of individual particles and the overdamped, sliding motion of particle clusters. The crossover in behaviour observed in experiments on piles of rice is attributed to a change in the dominant mode of transport. We predict that power law avalanching will be observed whenever surface flow is dominated by clustered motion.

  14. Granular neural networks, pattern recognition and bioinformatics

    Pal, Sankar K; Ganivada, Avatharam

    2017-01-01

    This book provides a uniform framework describing how fuzzy rough granular neural network technologies can be formulated and used in building efficient pattern recognition and mining models. It also discusses the formation of granules in the notion of both fuzzy and rough sets. Judicious integration in forming fuzzy-rough information granules based on lower approximate regions enables the network to determine the exactness in class shape as well as to handle the uncertainties arising from overlapping regions, resulting in efficient and speedy learning with enhanced performance. Layered network and self-organizing analysis maps, which have a strong potential in big data, are considered as basic modules,. The book is structured according to the major phases of a pattern recognition system (e.g., classification, clustering, and feature selection) with a balanced mixture of theory, algorithm, and application. It covers the latest findings as well as directions for future research, particularly highlighting bioinf...

  15. Regional expression and ultrastructural localization of EphA7 in the hippocampus and cerebellum of adult rat.

    Amegandjin, Clara A; Jammow, Wafaa; Laforest, Sylvie; Riad, Mustapha; Baharnoori, Moogeh; Badeaux, Frédérique; DesGroseillers, Luc; Murai, Keith K; Pasquale, Elena B; Drolet, Guy; Doucet, Guy

    2016-08-15

    EphA7 is expressed in the adult central nervous system (CNS), where its roles are yet poorly defined. We mapped its distribution using in situ hybridization (ISH) and immunohistochemistry (IHC) combined with light (LM) and electron microscopy (EM) in adult rat and mouse brain. The strongest ISH signal was in the hippocampal pyramidal and granule cell layers. Moderate levels were detected in habenula, striatum, amygdala, the cingulate, piriform and entorhinal cortex, and in cerebellum, notably the Purkinje cell layer. The IHC signal distribution was consistent with ISH results, with transport of the protein to processes, as exemplified in the hippocampal neuropil layers and weakly stained pyramidal cell layers. In contrast, in the cerebellum, the Purkinje cell bodies were the most strongly immunolabeled elements. EM localized the cell surface-expression of EphA7 essentially in postsynaptic densities (PSDs) of dendritic spines and shafts, and on some astrocytic leaflets, in both hippocampus and cerebellum. Perikaryal and dendritic labeling was mostly intracellular, associated with the synthetic and trafficking machineries. Immunopositive vesicles were also observed in axons and axon terminals. Quantitative analysis in EM showed significant differences in the frequency of labeled elements between regions. Notably, labeled dendrites were ∼3-5 times less frequent in cerebellum than in hippocampus, but they were individually endowed with ∼10-40 times higher frequencies of PSDs, on their shafts and spines. The cell surface localization of EphA7, being preferentially in PSDs, and in perisynaptic astrocytic leaflets, provides morphologic evidence that EphA7 plays key roles in adult CNS synaptic maintenance, plasticity, or function. J. Comp. Neurol. 524:2462-2478, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  16. Dynamics of crater formations in immersed granular materials

    Varas, G.; Vidal, V.; Géminard, J.

    2009-12-01

    Craters are part of the widespread phenomena observed in nature. Among the main applications to natural phenomena, aside from meteorite impact craters, are the formation and growth of volcanic edifices, by successive ejecta emplacement and/or erosion. The time evolution and dynamics play a crucial role here, as the competition between volcanic-jet mass-flux (degassing and ejecta) and crater-size evolution may control directly the eruptive regime. Crater morphology in dry granular material has been extensively studied, both experimentally and theoretically. Most of these studies investigate the final, steady crater shape resulting from the collision of solid bodies with the material surface and scaling laws are derived. In immersed granular material, craters generated by an underwater vortex ring, or underwater impact craters generated by landslide, have been reported. In a previous experimental study, Gostiaux et al. [Gran. Matt., 2002] have investigated the dynamics of air flowing through an immersed granular layer. They reported that, depending on the flow rate, the system exhibits two qualitatively different regimes: At small flow rate, the bubbling regime during which bubbles escape the granular layer independently one from another; At large flow rate, the open-channel regime which corresponds to the formation of a channel crossing the whole thickness of the granular bed through which air escapes almost continuously. At intermediate flow rate, a spontaneous alternation between these two regimes is observed. Here, we report the dynamics of crater formations at the free surface of an immersed granular bed, locally crossed by an ascending gas flow. We reproduce the experimental conditions of Gostiaux et al. (2002) in two dimensions: In a vertical Hele-Shaw cell, the crater consists of two sand piles which develop around the location of the gas emission. We observe that the typical size of the crater increases logarithmically with time, independently of the gas

  17. Consensus paper: Language and the cerebellum: an ongoing enigma.

    Mariën, Peter; Ackermann, Herman; Adamaszek, Michael; Barwood, Caroline H S; Beaton, Alan; Desmond, John; De Witte, Elke; Fawcett, Angela J; Hertrich, Ingo; Küper, Michael; Leggio, Maria; Marvel, Cherie; Molinari, Marco; Murdoch, Bruce E; Nicolson, Roderick I; Schmahmann, Jeremy D; Stoodley, Catherine J; Thürling, Markus; Timmann, Dagmar; Wouters, Ellen; Ziegler, Wolfram

    2014-06-01

    In less than three decades, the concept "cerebellar neurocognition" has evolved from a mere afterthought to an entirely new and multifaceted area of neuroscientific research. A close interplay between three main strands of contemporary neuroscience induced a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Indeed, the wealth of current evidence derived from detailed neuroanatomical investigations, functional neuroimaging studies with healthy subjects and patients and in-depth neuropsychological assessment of patients with cerebellar disorders shows that the cerebellum has a cardinal role to play in affective regulation, cognitive processing, and linguistic function. Although considerable progress has been made in models of cerebellar function, controversy remains regarding the exact role of the "linguistic cerebellum" in a broad variety of nonmotor language processes. This consensus paper brings together a range of different viewpoints and opinions regarding the contribution of the cerebellum to language function. Recent developments and insights in the nonmotor modulatory role of the cerebellum in language and some related disorders will be discussed. The role of the cerebellum in speech and language perception, in motor speech planning including apraxia of speech, in verbal working memory, in phonological and semantic verbal fluency, in syntax processing, in the dynamics of language production, in reading and in writing will be addressed. In addition, the functional topography of the linguistic cerebellum and the contribution of the deep nuclei to linguistic function will be briefly discussed. As such, a framework for debate and discussion will be offered in this consensus paper.

  18. Acoustic waves in granular materials

    Mouraille, O.J.P.; Luding, Stefan

    2008-01-01

    Dynamic simulations with discrete elements are used to obtain more insight into the wave propagation in dense granular media. A small perturbation is created on one side of a dense, static packing and examined during its propagation until it arrives at the opposite side. The influence of

  19. Sidewall-friction-driven ordering transition in granular channel flows: Implications for granular rheology

    Mandal, Sandip; Khakhar, D. V.

    2017-11-01

    We report a transition from a disordered state to an ordered state in the flow of nearly monodisperse granular matter flowing in an inclined channel with planar slide walls and a bumpy base, using discrete element method simulations. For low particle-sidewall friction coefficients, the flowing particles are disordered, however, for high sidewall friction, an ordered state is obtained, characterized by a layering of the particles and hexagonal packing of the particles in each layer. The extent of ordering, quantified by the local bond-orientational order parameter, varies in the cross section of the channel, with the highest ordering near the sidewalls. The flow transition significantly affects the local rheology—the effective friction coefficient is lower, and the packing fraction is higher, in the ordered state compared to the disordered state. A simple model, incorporating the extent of local ordering, is shown to describe the rheology of the system.

  20. Sidewall-friction-driven ordering transition in granular channel flows: Implications for granular rheology.

    Mandal, Sandip; Khakhar, D V

    2017-11-01

    We report a transition from a disordered state to an ordered state in the flow of nearly monodisperse granular matter flowing in an inclined channel with planar slide walls and a bumpy base, using discrete element method simulations. For low particle-sidewall friction coefficients, the flowing particles are disordered, however, for high sidewall friction, an ordered state is obtained, characterized by a layering of the particles and hexagonal packing of the particles in each layer. The extent of ordering, quantified by the local bond-orientational order parameter, varies in the cross section of the channel, with the highest ordering near the sidewalls. The flow transition significantly affects the local rheology-the effective friction coefficient is lower, and the packing fraction is higher, in the ordered state compared to the disordered state. A simple model, incorporating the extent of local ordering, is shown to describe the rheology of the system.

  1. Granular boycott effect: How to mix granulates

    Duran, J.; Mazozi, T.

    1999-11-01

    Granular material can display the basic features of the Boycott effect in sedimentation. A simple experiment shows that granular material falls faster in an inclined tube than in a vertical tube, in analogy with the Boycott effect. As long as the inclination of the tube is above the avalanche threshold, descent of granular material in the tube causes internal convection which in turn results in an efficient mixture of the granular components. By contrast, as in analogous experiments in two dimensions, a vertical fall of granular material occurs via successive block fragmentation, resulting in poor mixing.

  2. Implications of Lateral Cerebellum in Proactive Control of Saccades.

    Kunimatsu, Jun; Suzuki, Tomoki W; Tanaka, Masaki

    2016-06-29

    Although several lines of evidence establish the involvement of the medial and vestibular parts of the cerebellum in the adaptive control of eye movements, the role of the lateral hemisphere of the cerebellum in eye movements remains unclear. Ascending projections from the lateral cerebellum to the frontal and parietal association cortices via the thalamus are consistent with a role of these pathways in higher-order oculomotor control. In support of this, previous functional imaging studies and recent analyses in subjects with cerebellar lesions have indicated a role for the lateral cerebellum in volitional eye movements such as anti-saccades. To elucidate the underlying mechanisms, we recorded from single neurons in the dentate nucleus of the cerebellum in monkeys performing anti-saccade/pro-saccade tasks. We found that neurons in the posterior part of the dentate nucleus showed higher firing rates during the preparation of anti-saccades compared with pro-saccades. When the animals made erroneous saccades to the visual stimuli in the anti-saccade trials, the firing rate during the preparatory period decreased. Furthermore, local inactivation of the recording sites with muscimol moderately increased the proportion of error trials, while successful anti-saccades were more variable and often had shorter latency during inactivation. Thus, our results show that neuronal activity in the cerebellar dentate nucleus causally regulates anti-saccade performance. Neuronal signals from the lateral cerebellum to the frontal cortex might modulate the proactive control signals in the corticobasal ganglia circuitry that inhibit early reactive responses and possibly optimize the speed and accuracy of anti-saccades. Although the lateral cerebellum is interconnected with the cortical eye fields via the thalamus and the pons, its role in eye movements remains unclear. We found that neurons in the caudal part of the lateral (dentate) nucleus of the cerebellum showed the increased

  3. Linking Essential Tremor to the Cerebellum: Physiological Evidence.

    Filip, Pavel; Lungu, Ovidiu V; Manto, Mario-Ubaldo; Bareš, Martin

    2016-12-01

    Essential tremor (ET), clinically characterized by postural and kinetic tremors, predominantly in the upper extremities, originates from pathological activity in the dynamic oscillatory network comprising the majority of nodes in the central motor network. Evidence indicates dysfunction in the thalamus, the olivocerebellar loops, and intermittent cortical engagement. Pathology of the cerebellum, a structure with architecture intrinsically predisposed to oscillatory activity, has also been implicated in ET as shown by clinical, neuroimaging, and pathological studies. Despite electrophysiological studies assessing cerebellar impairment in ET being scarce, their impact is tangible, as summarized in this review. The electromyography-magnetoencephalography combination provided the first direct evidence of pathological alteration in cortico-subcortical communication, with a significant emphasis on the cerebellum. Furthermore, complex electromyography studies showed disruptions in the timing of agonist and antagonist muscle activation, a process generally attributed to the cerebellum. Evidence pointing to cerebellar engagement in ET has also been found in electrooculography measurements, cerebellar repetitive transcranial magnetic stimulation studies, and, indirectly, in complex analyses of the activity of the ventral intermediate thalamic nucleus (an area primarily receiving inputs from the cerebellum), which is also used in the advanced treatment of ET. In summary, further progress in therapy will require comprehensive electrophysiological and physiological analyses to elucidate the precise mechanisms leading to disease symptoms. The cerebellum, as a major node of this dynamic oscillatory network, requires further study to aid this endeavor.

  4. Consensus paper: the role of the cerebellum in perceptual processes.

    Baumann, Oliver; Borra, Ronald J; Bower, James M; Cullen, Kathleen E; Habas, Christophe; Ivry, Richard B; Leggio, Maria; Mattingley, Jason B; Molinari, Marco; Moulton, Eric A; Paulin, Michael G; Pavlova, Marina A; Schmahmann, Jeremy D; Sokolov, Arseny A

    2015-04-01

    Various lines of evidence accumulated over the past 30 years indicate that the cerebellum, long recognized as essential for motor control, also has considerable influence on perceptual processes. In this paper, we bring together experts from psychology and neuroscience, with the aim of providing a succinct but comprehensive overview of key findings related to the involvement of the cerebellum in sensory perception. The contributions cover such topics as anatomical and functional connectivity, evolutionary and comparative perspectives, visual and auditory processing, biological motion perception, nociception, self-motion, timing, predictive processing, and perceptual sequencing. While no single explanation has yet emerged concerning the role of the cerebellum in perceptual processes, this consensus paper summarizes the impressive empirical evidence on this problem and highlights diversities as well as commonalities between existing hypotheses. In addition to work with healthy individuals and patients with cerebellar disorders, it is also apparent that several neurological conditions in which perceptual disturbances occur, including autism and schizophrenia, are associated with cerebellar pathology. A better understanding of the involvement of the cerebellum in perceptual processes will thus likely be important for identifying and treating perceptual deficits that may at present go unnoticed and untreated. This paper provides a useful framework for further debate and empirical investigations into the influence of the cerebellum on sensory perception.

  5. Ablation of BRaf impairs neuronal differentiation in the postnatal hippocampus and cerebellum.

    Verena Pfeiffer

    Full Text Available This study focuses on the role of the kinase BRaf in postnatal brain development. Mice expressing truncated, non-functional BRaf in neural stem cell-derived brain tissue demonstrate alterations in the cerebellum, with decreased sizes and fuzzy borders of the glomeruli in the granule cell layer. In addition we observed reduced numbers and misplaced ectopic Purkinje cells that showed an altered structure of their dendritic arborizations in the hippocampus, while the overall cornus ammonis architecture appeared to be unchanged. In male mice lacking BRaf in the hippocampus the size of the granule cell layer was normal at postnatal day 12 (P12 but diminished at P21, as compared to control littermates. This defect was caused by a reduced ability of dentate gyrus progenitor cells to differentiate into NeuN positive granule cell neurons. In vitro cell culture of P0/P1 hippocampal cells revealed that BRaf deficient cells were impaired in their ability to form microtubule-associated protein 2 positive neurons. Together with the alterations in behaviour, such as autoaggression and loss of balance fitness, these observations indicate that in the absence of BRaf all neuronal cellular structures develop, but neuronal circuits in the cerebellum and hippocampus are partially disturbed besides impaired neuronal generation in both structures.

  6. Discrete element modeling of triggered slip in faults with granular gouge: application to dynamic earthquake triggering

    Ferdowsi, B.

    2014-01-01

    Recent seismological observations based on new, more sensitive instrumentation show that seismic waves radiated from large earthquakes can trigger other earthquakes globally. This phenomenon is called dynamic earthquake triggering and is well-documented for over 30 of the largest earthquakes worldwide. Granular materials are at the core of mature earthquake faults and play a key role in fault triggering by exhibiting a rich nonlinear response to external perturbations. The stick-slip dynamics in sheared granular layers is analogous to the seismic cycle for earthquake fault systems. In this research effort, we characterize the macroscopic scale statistics and the grain-scale mechanisms of triggered slip in sheared granular layers. We model the granular fault gouge using three dimensional discrete element method simulations. The modeled granular system is put into stick-slip dynamics by applying a conning pressure and a shear load. The dynamic triggering is simulated by perturbing the spontaneous stick-slip dynamics using an external vibration applied to the boundary of the layer. The influences of the triggering consist in a frictional weakening during the vibration interval, a clock advance of the next expected large slip event and long term effects in the form of suppression and recovery of the energy released from the granular layer. Our study suggests that above a critical amplitude, vibration causes a significant clock advance of large slip events. We link this clock advance to a major decline in the slipping contact ratio as well as a decrease in shear modulus and weakening of the granular gouge layer. We also observe that shear vibration is less effective in perturbing the stick-slip dynamics of the granular layer. Our study suggests that in order to have an effective triggering, the input vibration must also explore the granular layer at length scales about or less than the average grain size. The energy suppression and the subsequent recovery and increased

  7. Role of the cerebellum in reaching movements in humans. II. A neural model of the intermediate cerebellum.

    Schweighofer, N; Spoelstra, J; Arbib, M A; Kawato, M

    1998-01-01

    The cerebellum is essential for the control of multijoint movements; when the cerebellum is lesioned, the performance error is more than the summed errors produced by single joints. In the companion paper (Schweighofer et al., 1998), a functional anatomical model for visually guided arm movement was proposed. The model comprised a basic feedforward/feedback controller with realistic transmission delays and was connected to a two-link, six-muscle, planar arm. In the present study, we examined the role of the cerebellum in reaching movements by embedding a novel, detailed cerebellar neural network in this functional control model. We could derive realistic cerebellar inputs and the role of the cerebellum in learning to control the arm was assessed. This cerebellar network learned the part of the inverse dynamics of the arm not provided by the basic feedforward/feedback controller. Despite realistically low inferior olive firing rates and noisy mossy fibre inputs, the model could reduce the error between intended and planned movements. The responses of the different cell groups were comparable to those of biological cell groups. In particular, the modelled Purkinje cells exhibited directional tuning after learning and the parallel fibres, due to their length, provide Purkinje cells with the input required for this coordination task. The inferior olive responses contained two different components; the earlier response, locked to movement onset, was always present and the later response disappeared after learning. These results support the theory that the cerebellum is involved in motor learning.

  8. Circadian Clock Proteins and Melatonin Receptors in Neurons and Glia of the Sapajus apella Cerebellum

    Leila M. Guissoni Campos

    2018-02-01

    Full Text Available Oscillations of brain proteins in circadian rhythms are important for determining several cellular and physiological processes in anticipation of daily and seasonal environmental rhythms. In addition to the suprachiasmatic nucleus, the primary central oscillator, the cerebellum shows oscillations in gene and protein expression. The variety of local circuit rhythms that the cerebellar cortex contains influences functions such as motivational processes, regulation of feeding, food anticipation, language, and working memory. The molecular basis of the cerebellar oscillator has been demonstrated by “clock gene” expression within cells of the cerebellar layers. Genetic and epidemiological evidence suggests that disruption of circadian rhythms in humans can lead to many pathological conditions. Despite this importance, data about clock gene and protein expression in the cerebellum of diurnal (day-active species, specifically primates, is currently poorly explored, mainly in regard to cellular identity, as well as the relationship with other molecules also involved in cerebellar functions. These studies could contribute to clarification of the possible mechanisms behind cerebellar rhythmicity. Considering that calcium binding proteins (CaBPs play crucial roles in preserving and modulating cerebellar functions and that clock gene expression can be controlled by afferent projections or paracrine circadian signals such as the hormone melatonin, the present study aimed to describe cellular identities, distribution patterns and day/night expression changes in PER1, PER2, CaBPs, and MT1 and MT2 melatonin receptors in the cerebellar cortex of a diurnal primate using conventional fluorescence and peroxidase-antiperoxidase immunocytochemical techniques. PER1 and PER2 immunoreactive (IR cells were observed in the Purkinje cells of the cerebellum, and MT1 and MT2 receptors were localized around Purkinje cells in the Pj layer in Bergmann cells. This identity

  9. Consensus Paper: Language and the Cerebellum: an Ongoing Enigma

    Mariën, Peter; Ackermann, Herman; Adamaszek, Michael; Barwood, Caroline H. S.; Beaton, Alan; Desmond, John; De Witte, Elke; Fawcett, Angela J.; Hertrich, Ingo; Küper, Michael; Leggio, Maria; Marvel, Cherie; Molinari, Marco; Murdoch, Bruce E.; Nicolson, Roderick I.; Schmahmann, Jeremy D.; Stoodley, Catherine J.; Thürling, Markus; Timmann, Dagmar; Wouters, Ellen; Ziegler, Wolfram

    2014-01-01

    In less than three decades, the concept “cerebellar neurocognition” has evolved from a mere afterthought to an entirely new and multifaceted area of neuroscientific research. A close interplay between three main strands of contemporary neuroscience induced a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Indeed, the wealth of current evidence derived from detailed neuroanatomical investigations, functional neuroimaging studies with healthy subjects and patients and in-depth neuropsychological assessment of patients with cerebellar disorders shows that the cerebellum has a cardinal role to play in affective regulation, cognitive processing, and linguistic function. Although considerable progress has been made in models of cerebellar function, controversy remains regarding the exact role of the “linguistic cerebellum” in a broad variety of nonmotor language processes. This consensus paper brings together a range of different viewpoints and opinions regarding the contribution of the cerebellum to language function. Recent developments and insights in the nonmotor modulatory role of the cerebellum in language and some related disorders will be discussed. The role of the cerebellum in speech and language perception, in motor speech planning including apraxia of speech, in verbal working memory, in phonological and semantic verbal fluency, in syntax processing, in the dynamics of language production, in reading and in writing will be addressed. In addition, the functional topography of the linguistic cerebellum and the contribution of the deep nuclei to linguistic function will be briefly discussed. As such, a framework for debate and discussion will be offered in this consensus paper. PMID:24318484

  10. Where did the motor function of the cerebellum come from?

    Coco, Marinella; Perciavalle, Vincenzo

    2015-01-01

    Until the end of 18th century, the role of the cerebellum remained obscure. The turning point occurred when Luigi Galvani showed that muscle contraction is due to electricity and Alessandro Volta produced the battery, an apparatus based on the pairing of silver and zinc plates separated by brine soaked paper disks, capable to generate electricity. Luigi Rolando, at beginning of 19th century, was impressed by these two observations. He thought that, since the brain generates the movement, it must contain a device generating electricity. As a battery, it should be formed by overlapping disks and the cerebellum for Rolando seemed to be the right structure for such a characteristic laminar organization. He argued that, if the cerebellum is the battery that produces electricity for muscle activity, its removal would produce paralysis. Consequently, Rolando removed the cerebellum in a young goat and observed that the animal, before dying, could no longer stand up. He concluded that the cerebellum is a motor structure as it generates the electricity which produces the movement. The conclusions of Rolando were criticized by Marie-Jean-Pierre Flourens who observed that animals undergoing cerebellectomy were still able to move, even if with problems of balance. Flourens concluded that the role of the cerebellum "is to put in order or to coordinate movements wanted by certain parts of the nervous system, excited by others". It was necessary to wait up to 1891 when Luigi Luciani, observing a dog survived the cerebellectomy, described a triad of symptoms (asthenia, atony and astasis), unquestionably of cerebellar origin.

  11. The evolution of cerebellum structure correlates with nest complexity.

    Hall, Zachary J; Street, Sally E; Healy, Susan D

    2013-01-01

    Across the brains of different bird species, the cerebellum varies greatly in the amount of surface folding (foliation). The degree of cerebellar foliation is thought to correlate positively with the processing capacity of the cerebellum, supporting complex motor abilities, particularly manipulative skills. Here, we tested this hypothesis by investigating the relationship between cerebellar foliation and species-typical nest structure in birds. Increasing complexity of nest structure is a measure of a bird's ability to manipulate nesting material into the required shape. Consistent with our hypothesis, avian cerebellar foliation increases as the complexity of the nest built increases, setting the scene for the exploration of nest building at the neural level.

  12. Arterial territories of human brain: brainstem and cerebellum

    Tatu, L.; Moulin, T.; Bogousslavsky, J.; Duvernoy, H.

    1997-01-01

    The development of neuroimaging has allowed clinicians to improve clinico-anatomic correlations in patients with strokes. Brainstem and cerebellum structures are well delineated on MRI, but there is a lack of standardization in their arterial supply. We present a system of 12 brainstem and cerebellum axial sections, depicting the dominant arterial territories and the most important anatomic structures. These sections may be used as a practical tool to determine arterial territories on MRI, and may help establish consistent clinico-anatomic correlations in patients with brainstem and cerebellar ischemic strokes. (authors)

  13. Bubbling in vibrated granular films.

    Zamankhan, Piroz

    2011-02-01

    With the help of experiments, computer simulations, and a theoretical investigation, a general model is developed of the flow dynamics of dense granular media immersed in air in an intermediate regime where both collisional and frictional interactions may affect the flow behavior. The model is tested using the example of a system in which bubbles and solid structures are produced in granular films shaken vertically. Both experiments and large-scale, three-dimensional simulations of this system are performed. The experimental results are compared with the results of the simulation to verify the validity of the model. The data indicate evidence of formation of bubbles when peak acceleration relative to gravity exceeds a critical value Γ(b). The air-grain interfaces of bubblelike structures are found to exhibit fractal structure with dimension D=1.7±0.05.

  14. Strain localisation in granular media

    Desrues , Jacques

    1984-01-01

    This study is devoted to strain localisation in Granular materials. Both experimental and theoretical results have been obtained.The first part of the thesis is a review of the methods and theories about rupture in sols mechanics and more generally, in solid mechanics. The classical framework of Shear Band analysis is presented, and the main results available for different classes of materials are discussed.The second part describes an experimental study of strain localisation in sand specime...

  15. Paediatric laryngeal granular cell tumour

    Dauda Ayuba

    2009-01-01

    Full Text Available Granular cell tumour (GCT affecting the larynx is not common, especially in children. Most cases are apt to be confused with respiratory papilloma and may even be mistaken for a malignant neoplasia. We present a case of laryngeal GCT in a 12-year-old child to emphasize that the tumour should be regarded in the differential of growths affecting the larynx in children.

  16. Using a million cell simulation of the cerebellum: network scaling and task generality.

    Li, Wen-Ke; Hausknecht, Matthew J; Stone, Peter; Mauk, Michael D

    2013-11-01

    Several factors combine to make it feasible to build computer simulations of the cerebellum and to test them in biologically realistic ways. These simulations can be used to help understand the computational contributions of various cerebellar components, including the relevance of the enormous number of neurons in the granule cell layer. In previous work we have used a simulation containing 12000 granule cells to develop new predictions and to account for various aspects of eyelid conditioning, a form of motor learning mediated by the cerebellum. Here we demonstrate the feasibility of scaling up this simulation to over one million granule cells using parallel graphics processing unit (GPU) technology. We observe that this increase in number of granule cells requires only twice the execution time of the smaller simulation on the GPU. We demonstrate that this simulation, like its smaller predecessor, can emulate certain basic features of conditioned eyelid responses, with a slight improvement in performance in one measure. We also use this simulation to examine the generality of the computation properties that we have derived from studying eyelid conditioning. We demonstrate that this scaled up simulation can learn a high level of performance in a classic machine learning task, the cart-pole balancing task. These results suggest that this parallel GPU technology can be used to build very large-scale simulations whose connectivity ratios match those of the real cerebellum and that these simulations can be used guide future studies on cerebellar mediated tasks and on machine learning problems. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Impact Compaction of a Granular Material

    Fenton, Gregg; Asay, Blaine; Todd, Steve; Grady, Dennis

    2017-06-01

    The dynamic behavior of granular materials has importance to a variety of engineering applications. Although, the mechanical behavior of granular materials have been studied extensively for several decades, the dynamic behavior of these materials remains poorly understood. High-quality experimental data are needed to improve our general understanding of granular material compaction physics. This paper describes how an instrumented plunger impact system can be used to measure the compaction process for granular materials at high and controlled strain rates and subsequently used for computational modelling. The experimental technique relies on a gas-gun driven plunger system to generate a compaction wave through a volume of granular material. This volume of material has been redundantly instrumented along the bed length to track the progression of the compaction wave, and the piston displacement is measured with Photon Doppler Velocimetry (PDV). Using the gathered experimental data along with the initial material tap density, a granular material equation of state can be determined.

  18. Granular packing as model glass formers

    Wang Yujie

    2017-01-01

    Static granular packings are model hard-sphere glass formers. The nature of glass transition has remained a hotly debated issue. We review recent experimental progresses in using granular materials to study glass transitions. We focus on the growth of glass order with five-fold symmetry in granular packings and relate the findings to both geometric frustration and random first-order phase transition theories. (paper)

  19. Oscillations, Timing, Plasticity, and Learning in the Cerebellum.

    Cheron, G; Márquez-Ruiz, J; Dan, B

    2016-04-01

    The highly stereotyped, crystal-like architecture of the cerebellum has long served as a basis for hypotheses with regard to the function(s) that it subserves. Historically, most clinical observations and experimental work have focused on the involvement of the cerebellum in motor control, with particular emphasis on coordination and learning. Two main models have been suggested to account for cerebellar functioning. According to Llinás's theory, the cerebellum acts as a control machine that uses the rhythmic activity of the inferior olive to synchronize Purkinje cell populations for fine-tuning of coordination. In contrast, the Ito-Marr-Albus theory views the cerebellum as a motor learning machine that heuristically refines synaptic weights of the Purkinje cell based on error signals coming from the inferior olive. Here, we review the role of timing of neuronal events, oscillatory behavior, and synaptic and non-synaptic influences in functional plasticity that can be recorded in awake animals in various physiological and pathological models in a perspective that also includes non-motor aspects of cerebellar function. We discuss organizational levels from genes through intracellular signaling, synaptic network to system and behavior, as well as processes from signal production and processing to memory, delegation, and actual learning. We suggest an integrative concept for control and learning based on articulated oscillation templates.

  20. New roles for the cerebellum in health and disease

    Stacey L Reeber

    2013-11-01

    Full Text Available The cerebellum has a well-established role in maintaining motor coordination and studies of cerebellar learning suggest that it does this by recognizing neural patterns, which it uses to predict optimal movements. Serious damage to the cerebellum impairs this learning and results in a set of motor disturbances called ataxia. However, recent work implicates the cerebellum in cognition and emotion, and it has been argued that cerebellar dysfunction contributes to non-motor conditions such as autism spectrum disorders. Based on human and animal model studies, two major questions arise. Does the cerebellum contribute to non-motor as well as motor diseases, and if so, how does altering its function contribute to such diverse symptoms? The architecture and connectivity of cerebellar circuits may hold the answers to these questions. An emerging view is that cerebellar defects can trigger motor and non-motor neurological conditions by globally influencing brain function. Furthermore, during development cerebellar circuits may play a role in wiring events necessary for higher cognitive functions such as social behavior and language. We discuss genetic, electrophysiological, and behavioral evidence that implicates Purkinje cell dysfunction as a major culprit in several diseases and offer a hypothesis as to how canonical cerebellar functions might be at fault in non-motor as well as motor diseases.

  1. In vivo three-photon imaging of deep cerebellum

    Wang, Mengran; Wang, Tianyu; Wu, Chunyan; Li, Bo; Ouzounov, Dimitre G.; Sinefeld, David; Guru, Akash; Nam, Hyung-Song; Capecchi, Mario R.; Warden, Melissa R.; Xu, Chris

    2018-02-01

    We demonstrate three-photon microscopy (3PM) of mouse cerebellum at 1 mm depth by imaging both blood vessels and neurons. We compared 3PM and 2PM in the mouse cerebellum for imaging green (using excitation sources at 1300 nm and 920 nm, respectively) and red fluorescence (using excitation sources at 1680 nm and 1064 nm, respectively). 3PM enabled deeper imaging than 2PM because the use of longer excitation wavelength reduces the scattering in biological tissue and the higher order nonlinear excitation provides better 3D localization. To illustrate these two advantages quantitatively, we measured the signal decay as well as the signal-to-background ratio (SBR) as a function of depth. We performed 2-photon imaging from the brain surface all the way down to the area where the SBR reaches 1, while at the same depth, 3PM still has SBR above 30. The segmented decay curve shows that the mouse cerebellum has different effective attenuation lengths at different depths, indicating heterogeneous tissue property for this brain region. We compared the third harmonic generation (THG) signal, which is used to visualize myelinated fibers, with the decay curve. We found that the regions with shorter effective attenuation lengths correspond to the regions with more fibers. Our results indicate that the widespread, non-uniformly distributed myelinated fibers adds heterogeneity to mouse cerebellum, which poses additional challenges in deep imaging of this brain region.

  2. Cerebellum, Language, and Cognition in Autism and Specific Language Impairment

    Hodge, Steven M.; Makris, Nikos; Kennedy, David N.; Caviness, Verne S., Jr.; Howard, James; McGrath, Lauren; Steele, Shelly; Frazier, Jean A.; Tager-Flusberg, Helen; Harris, Gordon J.

    2010-01-01

    We performed cerebellum segmentation and parcellation on magnetic resonance images from right-handed boys, aged 6-13 years, including 22 boys with autism [16 with language impairment (ALI)], 9 boys with Specific Language Impairment (SLI), and 11 normal controls. Language-impaired groups had reversed asymmetry relative to unimpaired groups in…

  3. Linking Essential Tremor to the Cerebellum: Clinical Evidence.

    Benito-León, Julián; Labiano-Fontcuberta, Andrés

    2016-06-01

    Essential tremor (ET) might be a family of diseases unified by the presence of kinetic tremor, but also showing etiological, pathological, and clinical heterogeneity. In this review, we will describe the most significant clinical evidence, which suggests that ET is linked to the cerebellum. Data for this review were identified by searching PUBMED (January 1966 to May 2015) crossing the terms "essential tremor" (ET) and "cerebellum," which yielded 201 entries, 11 of which included the term "cerebellum" in the article title. This was supplemented by articles in the author's files that pertained to this topic. The wide spectrum of clinical features of ET that suggest that it originates as a cerebellar or cerebellar outflow problem include the presence of intentional tremor, gait and balance abnormalities, subtle features of dysarthria, and oculomotor abnormalities, as well as deficits in eye-hand coordination, motor learning deficits, incoordination during spiral drawing task, abnormalities in motor timing and visual reaction time, impairment of social abilities, improvement in tremor after cerebellar stroke, efficacy of deep brain stimulation (which blocks cerebellar outflow), and cognitive dysfunction. It is unlikely, however, that cerebellar dysfunction, per se, fully explains ET-associated dementia, because the cognitive deficits that have been described in patients with cerebellar lesions are generally mild. Overall, a variety of clinical findings suggest that in at least a sizable proportion of patients with ET, there is an underlying abnormality of the cerebellum and/or its pathways.

  4. The Cerebellum and Language: Evidence from Patients with Cerebellar Degeneration

    Stoodley, Catherine J.; Schmahmann, Jeremy D.

    2009-01-01

    Clinical and imaging studies suggest that the cerebellum is involved in language tasks, but the extent to which slowed language production in cerebellar patients contributes to their poor performance on these tasks is not clear. We explored this relationship in 18 patients with cerebellar degeneration and 16 healthy controls who completed measures…

  5. Editorial: The Cerebellum: Not Just an Anatomical Structure ...

    Evidences from cognitive studies further suggest that cerebellar pathology may be associated with alterations mainly in mental function, instead of motor processes. These pools of evidences continue to attract a sizeable number of researches into the neuroanatomy, neurobiology and neurobehavioral role of the cerebellum ...

  6. File list: InP.Neu.20.AllAg.Cerebellum [Chip-atlas[Archive

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  7. File list: Pol.Neu.10.AllAg.Cerebellum [Chip-atlas[Archive

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  8. File list: ALL.Neu.10.AllAg.Cerebellum [Chip-atlas[Archive

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  9. File list: ALL.Neu.50.AllAg.Cerebellum [Chip-atlas[Archive

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  10. File list: His.Neu.50.AllAg.Cerebellum [Chip-atlas[Archive

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  11. File list: InP.Neu.05.AllAg.Cerebellum [Chip-atlas[Archive

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  14. File list: Pol.Neu.50.AllAg.Cerebellum [Chip-atlas[Archive

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  15. File list: InP.Neu.10.AllAg.Cerebellum [Chip-atlas[Archive

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  16. File list: ALL.Neu.20.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available ALL.Neu.20.AllAg.Cerebellum hg19 All antigens Neural Cerebellum SRX1096823,SRX99829...5 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.20.AllAg.Cerebellum.bed ...

  17. File list: DNS.Neu.20.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available DNS.Neu.20.AllAg.Cerebellum mm9 DNase-seq Neural Cerebellum SRX191026,SRX191022,SRX...685872,SRX685874 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Neu.20.AllAg.Cerebellum.bed ...

  18. File list: Pol.Neu.05.AllAg.Cerebellum [Chip-atlas[Archive

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  19. File list: InP.Neu.50.AllAg.Cerebellum [Chip-atlas[Archive

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  20. File list: DNS.Neu.50.AllAg.Cerebellum [Chip-atlas[Archive

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  1. File list: DNS.Neu.05.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available DNS.Neu.05.AllAg.Cerebellum mm9 DNase-seq Neural Cerebellum SRX191026,SRX191022,SRX...685872,SRX685874,SRX685876 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Neu.05.AllAg.Cerebellum.bed ...

  2. File list: ALL.Neu.20.AllAg.Cerebellum [Chip-atlas[Archive

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  3. File list: Pol.Neu.20.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available Pol.Neu.20.AllAg.Cerebellum mm9 RNA polymerase Neural Cerebellum SRX062952,SRX14381...7,SRX026426,SRX026423,SRX026425,SRX026424 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.20.AllAg.Cerebellum.bed ...

  4. File list: DNS.Neu.10.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available DNS.Neu.10.AllAg.Cerebellum mm9 DNase-seq Neural Cerebellum SRX191026,SRX191022,SRX...685872,SRX685874,SRX685876 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Neu.10.AllAg.Cerebellum.bed ...

  5. File list: ALL.Neu.05.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available ALL.Neu.05.AllAg.Cerebellum mm9 All antigens Neural Cerebellum SRX191026,SRX062950,...X669237,SRX150265,SRX019017,SRX685922,SRX685924,SRX150262,SRX685876,SRX150263 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.05.AllAg.Cerebellum.bed ...

  6. File list: ALL.Neu.05.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available ALL.Neu.05.AllAg.Cerebellum hg19 All antigens Neural Cerebellum SRX998295,SRX109682...3 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.05.AllAg.Cerebellum.bed ...

  7. Theoretical model of granular compaction

    Ben-Naim, E. [Los Alamos National Lab., NM (United States); Knight, J.B. [Princeton Univ., NJ (United States). Dept. of Physics; Nowak, E.R. [Univ. of Illinois, Urbana, IL (United States). Dept. of Physics]|[Univ. of Chicago, IL (United States). James Franck Inst.; Jaeger, H.M.; Nagel, S.R. [Univ. of Chicago, IL (United States). James Franck Inst.

    1997-11-01

    Experimental studies show that the density of a vibrated granular material evolves from a low density initial state into a higher density final steady state. The relaxation towards the final density follows an inverse logarithmic law. As the system approaches its final state, a growing number of beads have to be rearranged to enable a local density increase. A free volume argument shows that this number grows as N = {rho}/(1 {minus} {rho}). The time scale associated with such events increases exponentially e{sup {minus}N}, and as a result a logarithmically slow approach to the final state is found {rho} {infinity} {minus}{rho}(t) {approx_equal} 1/lnt.

  8. NMR experiments on a three-dimensional vibrofluidized granular medium

    Huan, Chao; Yang, Xiaoyu; Candela, D.; Mair, R. W.; Walsworth, R. L.

    2004-04-01

    A three-dimensional granular system fluidized by vertical container vibrations was studied using pulsed field gradient NMR coupled with one-dimensional magnetic resonance imaging. The system consisted of mustard seeds vibrated vertically at 50 Hz, and the number of layers Nl⩽4 was sufficiently low to achieve a nearly time-independent granular fluid. Using NMR, the vertical profiles of density and granular temperature were directly measured, along with the distributions of vertical and horizontal grain velocities. The velocity distributions showed modest deviations from Maxwell-Boltzmann statistics, except for the vertical velocity distribution near the sample bottom, which was highly skewed and non-Gaussian. Data taken for three values of Nl and two dimensionless accelerations Γ=15,18 were fitted to a hydrodynamic theory, which successfully models the density and temperature profiles away from the vibrating container bottom. A temperature inversion near the free upper surface is observed, in agreement with predictions based on the hydrodynamic parameter μ which is nonzero only in inelastic systems.

  9. Storage and discharge of a granular fluid

    Pacheco-Martinez, Hector; van Gerner, H.J.; Ruiz-Suarez, J.C.

    2008-01-01

    Experiments and computational simulations are carried out to study the behavior of a granular column in a silo whose walls are able to vibrate horizontally. The column is brought to a steady fluidized state and it behaves similar to a hydrostatic system. We study the dynamics of the granular

  10. Characterization of Unbound Granular Materials for Pavements

    Araya, A.A.

    2011-01-01

    This research is focused on the characterization of the mechanical behavior of unbound granular road base materials (UGMs). An extensive laboratory investigation is described, in which various methods for determination of the mechanical properties of granular materials are examined for their

  11. Periurethral granular cell tumor: a case report

    Kim, Jeong Kon; Choi, Hyo Gyeong; Cho, Kyoung Sik

    1998-01-01

    Granular cell tumors are uncommon soft tissue tumors which arise as solitary or multiple masses. Lesions commonly arise in the head, neck, and chest wall, but can occur in any part of the body. To our knowledge, periurethral granular cell tumor has not been previously reported. We report one such case

  12. Viscosity evolution of anaerobic granular sludge

    Pevere, A.; Guibaud, G.; Hullebusch, van E.D.; Lens, P.N.L.; Baudu, M.

    2006-01-01

    The evolution of the apparent viscosity at steady shear rate of sieved anaerobic granular sludge (20¿315 ¿m diameter) sampled from different full-scale anaerobic reactors was recorded using rotation tests. The ¿limit viscosity¿ of sieved anaerobic granular sludge was determined from the apparent

  13. Electrical transport properties in Fe-Cr nanocluster-assembled granular films

    Wang, Xiong-Zhi; Wang, Lai-Sen; Zhang, Qin-Fu; Liu, Xiang; Xie, Jia; Su, A.-Mei; Zheng, Hong-Fei; Peng, Dong-Liang

    2017-09-01

    The Fe100-xCrx nanocluster-assembled granular films with Cr atomic fraction (x) ranging from 0 to 100 were fabricated by using a plasma-gas-condensation cluster deposition system. The TEM characterization revealed that the uniform Fe clusters were coated with a Cr layer to form a Fe-Cr core-shell structure. Then, the as-prepared Fe100-xCrx nanoclusters were randomly assembled into a granular film in vacuum environments with increasing the deposition time. Because of the competition between interfacial resistance and shunting effect of Cr layer, the room temperature resistivity of the Fe100-xCrx nanocluster-assembled granular films first increased and then decreased with increasing the Cr atomic fraction (x), and revealed a maximum of 2 × 104 μΩ cm at x = 26 at.%. The temperature-dependent longitudinal resistivity (ρxx), magnetoresistance (MR) effect and anomalous Hall effect (AHE) of these Fe100-xCrx nanocluster-assembled granular films were also studied systematically. As the x increased from 0 to 100, the ρxx of all samples firstly decreased and then increased with increasing the measuring temperature. The dependence of ρxx on temperature could be well addressed by a mechanism incorporated for the fluctuation-induced-tunneling (FIT) conduction process and temperature-dependent scattering effect. It was found that the anomalous Hall effect (AHE) had no legible scaling relation in Fe100-xCrx nanocluster-assembled granular films. However, after deducting the contribution of tunneling effect, the scaling relation was unambiguous. Additionally, the Fe100-xCrx nanocluster-assembled granular films revealed a small negative magnetoresistance (MR), which decreased with the increase of x. The detailed physical mechanism of the electrical transport properties in these Fe100-xCrx nanocluster-assembled granular films was also studied.

  14. RETRACTED: Granular and intergranular conduction in La{sub 1.32}Sr{sub 1.68}Mn{sub 2}O{sub 7} layered manganite system

    Narjis, A., E-mail: NARJIS78@gmail.com [Research Group ESNPS, Physics department, University Ibn Zohr, Faculty of Sciences, B.P 8106, Hay Dakhla, 80000 Agadir (Morocco); El kaaouachi, A.; Dlimi, S. [Research Group ESNPS, Physics department, University Ibn Zohr, Faculty of Sciences, B.P 8106, Hay Dakhla, 80000 Agadir (Morocco); Biskupski, G. [Laboratoire de Spectroscopie Hertzienne LSH, Bâtiment P5, Université des Sciences et Technologies, de Lille I 59 655 Villeneuve d’Ascq Cedex (France); Daoudi, E.; Errai, M.; Sybous, A.; Limouny, L. [Research Group ESNPS, Physics department, University Ibn Zohr, Faculty of Sciences, B.P 8106, Hay Dakhla, 80000 Agadir (Morocco)

    2013-06-15

    This article has been retracted: please see Elsevier Policy on Article Withdrawal ( (http://www.elsevier.com/locate/withdrawalpolicy)). This article has been retracted at the request of the Editors. The authors have plagiarized part of a paper that had already appeared in J. Appl. Phys. 106, 093709 (2009); (10.1063/1.3256182) (6 pages): Title: Effects of pressure on charge transport and magnetic properties of La1.32Sr1.68Mn2O7 layered manganite by M. Kumaresavanji, M. S. Reis, Y. T. Xing, and M. B. Fontes. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  15. Traffic and Granular Flow ’03

    Luding, Stefan; Bovy, Piet; Schreckenberg, Michael; Wolf, Dietrich

    2005-01-01

    These proceedings are the fifth in the series Traffic and Granular Flow, and we hope they will be as useful a reference as their predecessors. Both the realistic modelling of granular media and traffic flow present important challenges at the borderline between physics and engineering, and enormous progress has been made since 1995, when this series started. Still the research on these topics is thriving, so that this book again contains many new results. Some highlights addressed at this conference were the influence of long range electric and magnetic forces and ambient fluids on granular media, new precise traffic measurements, and experiments on the complex decision making of drivers. No doubt the “hot topics” addressed in granular matter research have diverged from those in traffic since the days when the obvious analogies between traffic jams on highways and dissipative clustering in granular flow intrigued both c- munities alike. However, now just this diversity became a stimulating feature of the ...

  16. Traffic and Granular Flow’05

    Pöschel, Thorsten; Kühne, Reinhart; Schreckenberg, Michael; Wolf, Dietrich

    2007-01-01

    The conference series Tra?c and Granular Flow has been established in 1995 and has since then been held biannually. At that time, the investigation of granular materials and tra?c was still somewhat exotic and was just starting to become popular among physicists. Originally the idea behind this conference series was to facilitate the c- vergence of the two ?elds, inspired by the similarities of certain phenomena and the use of similar theoretical methods. However, in recent years it has become clear that probably the di?erences between the two systems are much more interesting than the similarities. Nevertheless, the importance of various interrelations among these ?elds is still growing. The workshop continues to o?er an opportunity to stimulate this interdisciplinary research. Over the years the spectrum of topics has become much broader and has included also problems related to topics ranging from social dynamics to - ology. The conference manages to bring together people with rather di?erent background, r...

  17. Centrifuge modelling of granular flows

    Cabrera, Miguel Angel; Wu, Wei

    2015-04-01

    A common characteristic of mass flows like debris flows, rock avalanches and mudflows is that gravity is their main driving force. Gravity defines the intensity and duration of the main interactions between particles and their surrounding media (particle-particle, particle-fluid, fluid-fluid). At the same time, gravity delimits the occurrence of phase separation, inverse segregation, and mass consolidation, among other phenomena. Therefore, in the understanding of the flow physics it is important to account for the scaling of gravity in scaled models. In this research, a centrifuge model is developed to model free surface granular flows down an incline at controlled gravity conditions. Gravity is controlled by the action of an induced inertial acceleration field resulting from the rotation of the model in a geotechnical centrifuge. The characteristics of the induced inertial acceleration field during flow are discussed and validated via experimental data. Flow heights, velocity fields, basal pressure and impact forces are measured for a range of channel inclinations and gravity conditions. Preliminary results enlighten the flow characteristics at variable gravity conditions and open a discussion on the simulation of large scale processes at a laboratory scale. Further analysis on the flow physics brings valuable information for the validation of granular flows rheology.

  18. Cohesion-Induced Stabilization in Stick-Slip Dynamics of Weakly Wet, Sheared Granular Fault Gouge

    Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

    2018-03-01

    We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8,000 spherical particles with a polydisperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces between wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with 2 orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior; we show, however, that at low confining stresses, the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.

  19. A granular refillable filter for glas-flows contaminated by radioactive impurities

    Bonn, J.W.

    1975-01-01

    Description is given of a granular charcoal refillable filter adapted to adsorb the radioactive impurities of a gaseous flow. That flow comprises a number of filtering layers, the consumed charcoal of which can be discharged by a pneumatic device without exposing the personnel to radioactivity. This can be applied to emergency devices in nuclear facilities [fr

  20. Design and Prototyping of a High Granularity Scintillator Calorimeter

    Zutshi, Vishnu

    2016-01-01

    A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

  1. Design and Prototyping of a High Granularity Scintillator Calorimeter

    Zutshi, Vishnu [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics

    2016-03-27

    A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

  2. Targeting the Cerebellum by Noninvasive Neurostimulation: a Review.

    van Dun, Kim; Bodranghien, Florian; Manto, Mario; Mariën, Peter

    2017-06-01

    Transcranial magnetic and electric stimulation of the brain are novel and highly promising techniques currently employed in both research and clinical practice. Improving or rehabilitating brain functions by modulating excitability with these noninvasive tools is an exciting new area in neuroscience. Since the cerebellum is closely connected with the cerebral regions subserving motor, associative, and affective functions, the cerebello-thalamo-cortical pathways are an interesting target for these new techniques. Targeting the cerebellum represents a novel way to modulate the excitability of remote cortical regions and their functions. This review brings together the studies that have applied cerebellar stimulation, magnetic and electric, and presents an overview of the current knowledge and unsolved issues. Some recommendations for future research are implemented as well.

  3. Quantification of 5-hydroxytryptamine1A receptors in the cerebellum of normal and x-irradiated rats during postnatal development

    Matthiessen, L.; Daval, G.; Bailly, Y.; Gozlan, H.; Hamon, M.; Verge, D.

    1992-01-01

    5-Hydroxytryptamine 1A receptors were studied in rats during the first postnatal month in the normal cerebellum and in the granule cell-deprived cerebellum produced by X-irradiation at postnatal day 5. Quantitative autoradiographic studies on sagittal sections of cerebellar vermis, using [ 125 1]BH-8-MeO-N-PAT as radioligand or specific anti-receptor antibodies, revealed that 5-hydroxytryptamine 1A receptors existed in the molecular/Purkinje cell layer but at variable density from one lobule to another. Thus, in both normal and X-irradiated rats, the posterior lobules were more heavily labelled than the anterior ones, and the density of 5-hydroxytryptamine 1A sites decreased progressively in all the cerebellar folia down to hardly detectable levels at postnatal day 21. However, the intensity of labelling remained higher at postnatal day 8 and postnatal day 12 in X-irradiated rats than in age-paired controls. Measurements of [ 3 H]8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] specific binding to membranes from whole cerebellum confirmed that the density of 5-hydroxytryptamine 1A sites per mg membrane protein (B max ) was higher in X-irradiated animals than in age-paired controls. However, on a ''per cerebellum'' basis, no significant difference could be detected between the total number of 5-hydroxytryptamine 1A sites, which progressively increased in both control and X-irradiated animals during the first postnatal month. These results therefore show that 5-hydroxytryptamine 1A receptors are not located on developing granule cells. (author)

  4. MR diffusion histology and micro-tractography reveal mesoscale features of the human cerebellum.

    Dell'Acqua, Flavio; Bodi, Istvan; Slater, David; Catani, Marco; Modo, Michel

    2013-12-01

    After 140 years from the discovery of Golgi's black reaction, the study of connectivity of the cerebellum remains a fascinating yet challenging task. Current histological techniques provide powerful methods for unravelling local axonal architecture, but the relatively low volume of data that can be acquired in a reasonable amount of time limits their application to small samples. State-of-the-art in vivo magnetic resonance imaging (MRI) methods, such as diffusion tractography techniques, can reveal trajectories of the major white matter pathways, but their correspondence with underlying anatomy is yet to be established. Hence, a significant gap exists between these two approaches as neither of them can adequately describe the three-dimensional complexity of fibre architecture at the level of the mesoscale (from a few millimetres to micrometres). In this study, we report the application of MR diffusion histology and micro-tractography methods to reveal the combined cytoarchitectural organisation and connectivity of the human cerebellum at a resolution of 100-μm (2 nl/voxel volume). Results show that the diffusion characteristics for each layer of the cerebellar cortex correctly reflect the known cellular composition and its architectural pattern. Micro-tractography also reveals details of the axonal connectivity of individual cerebellar folia and the intra-cortical organisation of the different cerebellar layers. The direct correspondence between MR diffusion histology and micro-tractography with immunohistochemistry indicates that these approaches have the potential to complement traditional histology techniques by providing a non-destructive, quantitative and three-dimensional description of the microstructural organisation of the healthy and pathological tissue.

  5. A role for cerebellum in the hereditary dystonia DYT1

    Fremont, Rachel; Tewari, Ambika; Angueyra, Chantal; Khodakhah, Kamran

    2017-01-01

    DYT1 is a debilitating movement disorder caused by loss-of-function mutations in torsinA. How these mutations cause dystonia remains unknown. Mouse models which have embryonically targeted torsinA have failed to recapitulate the dystonia seen in patients, possibly due to differential developmental compensation between rodents and humans. To address this issue, torsinA was acutely knocked down in select brain regions of adult mice using shRNAs. TorsinA knockdown in the cerebellum, but not in the basal ganglia, was sufficient to induce dystonia. In agreement with a potential developmental compensation for loss of torsinA in rodents, torsinA knockdown in the immature cerebellum failed to produce dystonia. Abnormal motor symptoms in knockdown animals were associated with irregular cerebellar output caused by changes in the intrinsic activity of both Purkinje cells and neurons of the deep cerebellar nuclei. These data identify the cerebellum as the main site of dysfunction in DYT1, and offer new therapeutic targets. DOI: http://dx.doi.org/10.7554/eLife.22775.001 PMID:28198698

  6. Functional relationship between the cerebrum and cerebellum in normal subjects

    Hanyu, Haruo; Arai, Hisayuki; Hatano, Nobuyoshi; Abe, Shinei; Katsunuma, Hideyo

    1991-01-01

    To determine whether a functional relationship between the cerebrum and cerebellum exists in normal subjects, the correlation between asymmetry in cerebral blood flow and asymmetry in cerebellar blood flow was investigated. Twenty-one healthy right-handed subjects were studied using SPECT with N-isopropyl-p-( 123 I)iodoamphetamine while in a resting state. The asymmetry index (AI) for both the cerebral and cerebellar hemisphere was calculated as follows. AI=right side - left side/right side + left side/200 (%). A negative correlation was found between AI in the cerebellum and AI in the cerebrum. Especially, AI in the cerebellar hemisphere was significantly correlated with AIs in the upper frontal cortex (r=-0.58, p<0.01), middle frontal cortex (r=-0.55, p<0.02), lower frontal cortex (r=-0.49, p<0.05), and mean cerebral hemisphere (r=-0.52, p<0.02). These results suggest the existence of a functional relationship between the cerebral hemisphere and the contralateral cerebellar hemisphere in the resting state of normal subjects. We strongly suspect that the frontal cortex exert an influence on the function in the contralateral cerebellum, probably due to a transneuronal mechanism, mainly through the corticopontocerebellar pathway. (author)

  7. Nitric oxide in the rat cerebellum after hypoxia/ischemia.

    Rodrigo, José; Fernández, Ana Patricia; Alonso, David; Serrano, Julia; Fernández-Vizarra, Paula; Martínez-Murillo, Ricardo; Bentura, María Luisa; Martinez, Alfredo

    2004-01-01

    Nitric oxide is a regulatory biological substance and an important intracellular messenger that acts as a specific mediator of various neuropathological disorders. In mammals and invertebrates, nitric oxide is synthesized from L-arginine in the central and peripheral neural structures by the endothelial, neuronal and inducible enzymatic isoforms of nitric oxide synthase. Nitric oxide may affect the function of various neurotransmitter-specific systems, and is involved in neuromodulation, reproductive function, immune response, and regulation of the cerebral blood circulation. This makes nitric oxide the main candidate in brain responses to brain ischemia/hypoxia. The cerebellum has been reported to be the area of the brain that has the highest nitric oxide synthase activity and the highest concentration of glutamate and aspartate. By glutamate receptors and physiological action of nitric oxide, cyclic guanisine-5'-monophosphate may be rapidly increased. The cerebellum significantly differs with respect to ischemia and hypoxia, this response being directly related to the duration and intensity of the injury. The cerebellum could cover the eventual need for nitric oxide during the hypoxia, boosting the nitric oxide synthase activity, but overall ischemia would require de novo protein synthesis, activating the inducible nitric oxide synthase to cope with the new situation. The specific inhibitors of nitric oxide synthesis show neuroprotective effects.

  8. Effect of Maternal Diabetes on Cerebellum Histomorphometry in Neonatal Rats

    Z Khaksar

    2010-04-01

    Full Text Available Introduction: In pregnant mothers, maternal diabetes occurs when pancreas can't produce enough insulin resulting in increased blood glucose levels in the mother and subsequently in the fetus. This investigation was conducted to evaluate the effects of maternal diabetes on cerebellum of offspring of diabetic mothers (ODM, which was carried out at the veterinary faculty of Shiraz University in 2007-2008. Methods: This was an experimental study that included sixteen normal adult female rats divided in two groups. Diabetes was induced in one group by Alloxan agent. Both groups became pregnant by natural mating . At 7, 14, 21 and 28 days after birth, the cerebellum of all offsprings were collected and the weight of neonates was also measured. After producing histological slides, Olympus BX51 microscope and ‍‍‍‍‍‍‍ Olysia softwarwere used. Various histological parameters used included gray and white matters thicknesses (µ, the number of cells in gray and white matter separately per unit and the ratio of gray matter to white matter. Results: Cerebellar parameters decreased in ODM as compared to the control group. The body weight of ODM was significantly more than that of the control group (p< 0.05. Conclusions: Maternal hyperglycaemia exhibited deleterious effects on cerebellum during fetal life, which remained persistent during postneonatal period. Maternal diabetes also resulted in reduction of number of cells and thicknesses of both gray and white matter.

  9. Aerofractures in Confined Granular Media

    Eriksen, Fredrik K.; Turkaya, Semih; Toussaint, Renaud; Måløy, Knut J.; Flekkøy, Eirik G.

    2015-04-01

    We will present the optical analysis of experimental aerofractures in confined granular media. The study of this generic process may have applications in industries involving hydraulic fracturing of tight rocks, safe construction of dams, tunnels and mines, and in earth science where phenomena such as mud volcanoes and sand injectites are results of subsurface sediment displacements driven by fluid overpressure. It is also interesting to increase the understanding the flow instability itself, and how the fluid flow impacts the solid surrounding fractures and in the rest of the sample. Such processes where previously studied numerically [Niebling 2012a, Niebling 2012b] or in circular geometries. We will here explore experimentally linear geometries. We study the fracturing patterns that form when air flows into a dense, non-cohesive porous medium confined in a Hele-Shaw cell - i.e. into a packing of dry 80 micron beads placed between two glass plates separated by ~1mm. The cell is rectangular and fitted with a semi-permeable boundary to the atmosphere - blocking beads but not air - on one short edge, while the other three edges are impermeable. The porous medium is packed inside the cell between the semi-permeable boundary and an empty volume at the sealed side where the air pressure can be set and kept at a constant overpressure (1-2bar). Thus, for the air trapped inside the cell to release the overpressure it has to move through the solid. At high enough overpressures the air flow deforms the solid and increase permeability in some regions along the air-solid interface, which results in unstable flow and aerofracturing. Aerofractures are thought to be an analogue to hydrofractures, and an advantage of performing aerofracturing experiments in a Hele-Shaw cell is that the fracturing process can easily be observed in the lab. Our experiments are recorded with a high speed camera with a framerate of 1000 frames per second. In the analysis, by using various image

  10. Granular metamaterials for vibration mitigation

    Gantzounis, G.; Serra-Garcia, M.; Homma, K.; Mendoza, J. M.; Daraio, C.

    2013-09-01

    Acoustic metamaterials that allow low-frequency band gaps are interesting for many practical engineering applications, where vibration control and sound insulation are necessary. In most prior studies, the mechanical response of these structures has been described using linear continuum approximations. In this work, we experimentally and theoretically address the formation of low-frequency band gaps in locally resonant granular crystals, where the dynamics of the system is governed by discrete equations. We investigate the quasi-linear behavior of such structures. The analysis shows that a stopband can be introduced at about one octave lower frequency than in materials without local resonances. Broadband and multi-frequency stopband characteristics can also be achieved by strategically tailoring the non-uniform local resonance parameters.

  11. Shear failure of granular materials

    Degiuli, Eric; Balmforth, Neil; McElwaine, Jim; Schoof, Christian; Hewitt, Ian

    2012-02-01

    Connecting the macroscopic behavior of granular materials with the microstructure remains a great challenge. Recent work connects these scales with a discrete calculus [1]. In this work we generalize this formalism from monodisperse packings of disks to 2D assemblies of arbitrarily shaped grains. In particular, we derive Airy's expression for a symmetric, divergence-free stress tensor. Using these tools, we derive, from first-principles and in a mean-field approximation, the entropy of frictional force configurations in the Force Network Ensemble. As a macroscopic consequence of the Coulomb friction condition at contacts, we predict shear failure at a critical shear stress, in accordance with the Mohr-Coulomb failure condition well known in engineering. Results are compared with numerical simulations, and the dependence on the microscopic geometric configuration is discussed. [4pt] [1] E. DeGiuli & J. McElwaine, PRE 2011. doi: 10.1103/PhysRevE.84.041310

  12. Mechanics of a granular skin

    Karmakar, Somnath; Sane, Anit; Bhattacharya, S.; Ghosh, Shankar

    2017-04-01

    Magic sand, a hydrophobic toy granular material, is widely used in popular science instructions because of its nonintuitive mechanical properties. A detailed study of the failure of an underwater column of magic sand shows that these properties can be traced to a single phenomenon: the system self-generates a cohesive skin that encapsulates the material inside. The skin, consisting of pinned air-water-grain interfaces, shows multiscale mechanical properties: they range from contact-line dynamics in the intragrain roughness scale, to plastic flow at the grain scale, all the way to sample-scale mechanical responses. With decreasing rigidity of the skin, the failure mode transforms from brittle to ductile (both of which are collective in nature) to a complete disintegration at the single-grain scale.

  13. Storage and discharge of a granular fluid.

    Pacheco-Martinez, Hector; van Gerner, Henk Jan; Ruiz-Suárez, J C

    2008-02-01

    Experiments and computational simulations are carried out to study the behavior of a granular column in a silo whose walls are able to vibrate horizontally. The column is brought to a steady fluidized state and it behaves similar to a hydrostatic system. We study the dynamics of the granular discharge through openings at the bottom of the silo in order to search for a Torricelli-like behavior. We show that the flow rate scales with the wall induced shear rate, and at high rates, the granular bed indeed discharges similar to a viscous fluid.

  14. Energy decay in a granular gas collapse

    Almazán, Lidia; Serero, Dan; Pöschel, Thorsten; Salueña, Clara

    2017-01-01

    An inelastic hard ball bouncing repeatedly off the ground comes to rest in finite time by performing an infinite number of collisions. Similarly, a granular gas under the influence of external gravity, condenses at the bottom of the confinement due to inelastic collisions. By means of hydrodynamical simulations, we find that the condensation process of a granular gas reveals a similar dynamics as the bouncing ball. Our result is in agreement with both experiments and particle simulations, but disagrees with earlier simplified hydrodynamical description. Analyzing the result in detail, we find that the adequate modeling of pressure plays a key role in continuum modeling of granular matter. (paper)

  15. On inconsistency in frictional granular systems

    Alart, Pierre; Renouf, Mathieu

    2018-04-01

    Numerical simulation of granular systems is often based on a discrete element method. The nonsmooth contact dynamics approach can be used to solve a broad range of granular problems, especially involving rigid bodies. However, difficulties could be encountered and hamper successful completion of some simulations. The slow convergence of the nonsmooth solver may sometimes be attributed to an ill-conditioned system, but the convergence may also fail. The prime aim of the present study was to identify situations that hamper the consistency of the mathematical problem to solve. Some simple granular systems were investigated in detail while reviewing and applying the related theoretical results. A practical alternative is briefly analyzed and tested.

  16. Shock waves in weakly compressed granular media.

    van den Wildenberg, Siet; van Loo, Rogier; van Hecke, Martin

    2013-11-22

    We experimentally probe nonlinear wave propagation in weakly compressed granular media and observe a crossover from quasilinear sound waves at low impact to shock waves at high impact. We show that this crossover impact grows with the confining pressure P0, whereas the shock wave speed is independent of P0-two hallmarks of granular shocks predicted recently. The shocks exhibit surprising power law attenuation, which we model with a logarithmic law implying that shock dissipation is weak and qualitatively different from other granular dissipation mechanisms. We show that elastic and potential energy balance in the leading part of the shocks.

  17. Nonlocal rheological properties of granular flows near a jamming limit.

    Aranson, Igor S; Tsimring, Lev S; Malloggi, Florent; Clément, Eric

    2008-09-01

    We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology. The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.

  18. Granular-relational data mining how to mine relational data in the paradigm of granular computing ?

    Hońko, Piotr

    2017-01-01

    This book provides two general granular computing approaches to mining relational data, the first of which uses abstract descriptions of relational objects to build their granular representation, while the second extends existing granular data mining solutions to a relational case. Both approaches make it possible to perform and improve popular data mining tasks such as classification, clustering, and association discovery. How can different relational data mining tasks best be unified? How can the construction process of relational patterns be simplified? How can richer knowledge from relational data be discovered? All these questions can be answered in the same way: by mining relational data in the paradigm of granular computing! This book will allow readers with previous experience in the field of relational data mining to discover the many benefits of its granular perspective. In turn, those readers familiar with the paradigm of granular computing will find valuable insights on its application to mining r...

  19. Bedrock erosion by sliding wear in channelized granular flow

    Hung, C. Y.; Stark, C. P.; Capart, H.; Smith, B.; Maia, H. T.; Li, L.; Reitz, M. D.

    2014-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Bedrock wear can be separated into impact and sliding wear processes. Here we focus on sliding wear. We have conducted experiments with a 40-cm-diameter grainflow-generating rotating drum designed to simulate dry channelized debris flows. To generate sliding erosion, we placed a 20-cm-diameter bedrock plate axially on the back wall of the drum. The rotating drum was half filled with 2.3-mm-diameter grains, which formed a thin grain-avalanching layer with peak flow speed and depth close to the drum axis. The whole experimental apparatus was placed on a 100g-ton geotechnical centrifuge and, in order to scale up the stress level, spun to a range of effective gravity levels. Rates and patterns of erosion of the bedrock plate were mapped after each experiment using 3d micro-photogrammetry. High-speed video and particle tracking were employed to measure granular flow dynamics. The resulting data for granular velocities and flow geometry were used to estimate impulse exchanges and forces on the bedrock plate. To address some of the complexities of granular flow under variable gravity levels, we developed a continuum model framed around a GDR MiDi rheology. This model allowed us to scale up boundary forcing while maintaining the same granular flow regime, and helped us to understand important aspects of the flow dynamics including e.g. fluxes of momentum and kinetic energy. In order to understand the detailed processes of boundary forcing, we performed numerical simulations with a new contact dynamics model. This model confirmed key aspects of our continuum model and provided information on second-order behavior such as fluctuations in the forces acting on the wall. By combining these measurements and theoretical analyses, we have developed and calibrated a constitutive model for sliding wear that is a threshold function of

  20. Statistical and visual probing of evolving granular assemblies

    Smith, Laurence M.

    2002-01-01

    The majority of processes in the chemical and allied industries involve the storage and conveyancing of granular material, the physics of which is still not particularly well understood. Whilst some non-invasive techniques have been developed, much experimental work unfortunately interferes with the fields being investigated. For this reason and in conjunction with increasing computing power, there has been an increase in simulation based studies. Granular dynamics simulations, being based upon inter-particle interaction laws, give the potential to investigate assemblies at the 'micro-level' and have been successful in modelling process conditions in a number of granular flow situations. To date, most analyses of these simulations are essentially static in nature involving 'time snapshots'. However, in a granular dynamics simulation there is a wealth of data available on a time referenced basis which has the potential to allow a quantitative analysis of the dynamics of assembly evolution. This dissertation describes the development and application of a toolkit for post-simulation analysis. However, the utilities within the toolkit would be equally applicable to large experimental data sets should such data sets exist. The application of the toolset focuses largely on the dynamics of heap evolution in both 2D and 3D with some supportive 3D work on hopper discharge. A major part of the work involves the application of time series techniques (including the wavelet transform) in the context of variable coupling during avalanching. Segregation by self-diffusion receives particular attention and a new mechanism is proposed by which segregation by particle size takes place in the boundary layer of a low impact feed heap displaying a clear velocity gradient during discrete avalanching. Periodic lateral surging is shown to enforce mixing for a high impact feed, a phenomenon which appears to switch off below a certain feed impact. Segregation by self-diffusion is also shown

  1. Cell-Targeted Optogenetics and Electrical Microstimulation Reveal the Primate Koniocellular Projection to Supra-granular Visual Cortex.

    Klein, Carsten; Evrard, Henry C; Shapcott, Katharine A; Haverkamp, Silke; Logothetis, Nikos K; Schmid, Michael C

    2016-04-06

    Electrical microstimulation and more recently optogenetics are widely used to map large-scale brain circuits. However, the neuronal specificity achieved with both methods is not well understood. Here we compare cell-targeted optogenetics and electrical microstimulation in the macaque monkey brain to functionally map the koniocellular lateral geniculate nucleus (LGN) projection to primary visual cortex (V1). Selective activation of the LGN konio neurons with CamK-specific optogenetics caused selective electrical current inflow in the supra-granular layers of V1. Electrical microstimulation targeted at LGN konio layers revealed the same supra-granular V1 activation pattern as the one elicited by optogenetics. Taken together, these findings establish a selective koniocellular LGN influence on V1 supra-granular layers, and they indicate comparable capacities of both stimulation methods to isolate thalamo-cortical circuits in the primate brain. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Multi-Anode Photomultplier (MAPMT) readout for High Granularity Calorimeters

    Mkrtchyan, Tigran; The ATLAS collaboration

    2017-01-01

    Hadron calorimeter high performance in jet sub-structure measurements can be achieved for objects with $p_{T}$ greater than 1 TeV if the readout geometry is finely segmented in $\\Delta\\eta \\times \\Delta\\phi$. A feasibility study to increase the readout granularity of TileCal, the central hadron calorimeter of the ATLAS detector, is presented. We show a preliminary study exploring the possibility to increase by a factor 4 the present readout granularity of the inner layer cells of TileCal (0.1->0.025 in $\\Delta\\eta$) and to split into two layers the intermediate section of TileCal. The proposed solution is designed to cope with mechanical and readout bandwidth and power constraints. Assuming that the mechanics of the Tile modules cannot be changed, Multi-Anode PMTs with same boundary geometry of the present single-anode PMTs are considered to readout WLS bers, ideally one per pixel, carrying the signals from the individual scintillating tiles of each detector cells. The discussed challenges of the design are: ...

  3. Spatial correlations in compressible granular flows

    van Noije, T.P.C.; Ernst, M.H.; Brito, R.

    The clustering instability in freely evolving granular fluids manifests itself in the density-density correlation function and structure factor. These functions are calculated from fluctuating hydrodynamics. As time increases, the structure factor of density fluctuations develops a maximum, which

  4. Granular Gases: Probing the Boundaries of Hydrodynamics

    Goldhirsch, I.

    1999-01-01

    The dissipative nature of the particle interactions in granular systems renders granular gases mesoscopic and bearing some similarities to regular gases in the ''continuum transition regime'' where shear rates and/or thermal gradients are very large). The following properties of granular gases support the above claim: (i). Mean free times are of the same order as macroscopic time scales (inverse shear rates); (ii). Mean free paths can be macroscopic and comparable to the system's dimensions; (iii). Typical flows are supersonic; (iv). Shear rates are typically ''large''; (v). Stress fields are scale (resolution) dependent; (vi). Burnett and super-Burnett corrections to both the constitutive relations and the boundary conditions are of importance; (vii). Single particle distribution functions can be far from Gaussian. It is concluded that while hydrodynamic descriptions of granular gases are relevant, they are probing the boundaries of applicability of hydrodynamics and perhaps slightly beyond

  5. Advanced Granular System Modeling, Phase I

    National Aeronautics and Space Administration — Spaceports of the future will utilize new granular materials in unique applications including insulation for cryogenic tanks and Lunar regolith processing for usable...

  6. Resistance capability of microaerobic granular sludge for ...

    enoh

    2012-02-08

    Feb 8, 2012 ... The resistance capability to pH shock of microaerobic granular sludge for pentachlorophenol (PCP) ... process with chlorine gas in pulp and paper, leather and spinning ... nitrifying bacteria in the aerobic zone, and then trans-.

  7. Microbiological aspects of granular methanogenic sludge

    Dolfing, J.

    1987-01-01

    The settling characteristics of anaerobic sludge are enhanced by the formation of microbial conglomerates. Various types of conglomerates having different structures, were distinguished in the present study, viz. granules, pellets and flocs (chapter 1). Granular methanogenic sludge, often

  8. NMR Measurements of Granular Flow and Compaction

    Fukushima, Eiichi

    1998-03-01

    Nuclear magnetic resonance (NMR) can be used to measure statistical distributions of granular flow velocity and fluctuations of velocity, as well as spatial distributions of particulate concentration, flow velocity, its fluctuations, and other parameters that may be derived from these. All measurements have been of protons in liquid-containing particles such as mustard seeds or pharmaceutical pills. Our favorite geometry has been the slowly rotating partially filled rotating drum with granular flow taking place along the free surface of the particles. All the above-mentioned parameters have been studied as well as a spatial distribution of particulate diffusion coefficients, energy dissipation due to collisions, as well as segregation of non-uniform mixtures of granular material. Finally, we describe some motions of granular material under periodic vibrations.

  9. Uniform shock waves in disordered granular matter.

    Gómez, Leopoldo R; Turner, Ari M; Vitelli, Vincenzo

    2012-10-01

    The confining pressure P is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates continuously decreases as the confining pressure decreases, completely vanishing at the jamming-unjamming transition. This anomalous behavior suggests that the transport of energy at low pressures should not be dominated by phonons. In this work we use simulations and theory to show how the response of granular systems becomes increasingly nonlinear as pressure decreases. In the low-pressure regime the elastic energy is found to be mainly transported through nonlinear waves and shocks. We numerically characterize the propagation speed, shape, and stability of these shocks and model the dependence of the shock speed on pressure and impact intensity by a simple analytical approach.

  10. Kinetic Theory of Granular Gases

    Trizac, Emmanuel [Center of Theoretical Biological Physics, UC San Diego, La Jolla, CA 92093-0374 (United States); Laboratoire de Physique Theorique et Modeles Statistiques, Campus Universitaire, 91405 Orsay (France)

    2005-11-25

    Granular gases are composed of macroscopic bodies kept in motion by an external energy source such as a violent shaking. The behaviour of such systems is quantitatively different from that of ordinary molecular gases: due to the size of the constituents, external fields have a stronger effect on the dynamics and, more importantly, the kinetic energy of the gas is no longer a conserved quantity. The key role of the inelasticity of collisions has been correctly appreciated for about fifteen years, and the ensuing consequences in terms of phase behaviour or transport properties studied in an increasing and now vast body of literature. The purpose of this book is to help the newcomer to the field in acquiring the essential theoretical tools together with some numerical techniques. As emphasized by the authors-who were among the pioneers in the domain- the content could be covered in a one semester course for advanced undergraduates, or it could be incorporated in a more general course dealing with the statistical mechanics of dissipative systems. The book is self-contained, clear, and avoids mathematical complications. In order to elucidate the main physical ideas, heuristic points of views are sometimes preferred to a more rigorous route that would lead to a longer discussion. The 28 chapters are short; they offer exercises and worked examples, solved at the end of the book. Each part is supplemented with a relevant foreword and a useful summary including take-home messages. The editorial work is of good quality, with very few typographical errors. In spite of the title, kinetic theory stricto sensu is not the crux of the matter covered. The authors discuss the consequences of the molecular chaos assumption both at the individual particle level and in terms of collective behaviour. The first part of the book addresses the mechanics of grain collisions. It is emphasized that considering the coefficient of restitution {epsilon} -a central quantity governing the

  11. Kinetic Theory of Granular Gases

    Trizac, Emmanuel

    2005-01-01

    Granular gases are composed of macroscopic bodies kept in motion by an external energy source such as a violent shaking. The behaviour of such systems is quantitatively different from that of ordinary molecular gases: due to the size of the constituents, external fields have a stronger effect on the dynamics and, more importantly, the kinetic energy of the gas is no longer a conserved quantity. The key role of the inelasticity of collisions has been correctly appreciated for about fifteen years, and the ensuing consequences in terms of phase behaviour or transport properties studied in an increasing and now vast body of literature. The purpose of this book is to help the newcomer to the field in acquiring the essential theoretical tools together with some numerical techniques. As emphasized by the authors-who were among the pioneers in the domain- the content could be covered in a one semester course for advanced undergraduates, or it could be incorporated in a more general course dealing with the statistical mechanics of dissipative systems. The book is self-contained, clear, and avoids mathematical complications. In order to elucidate the main physical ideas, heuristic points of views are sometimes preferred to a more rigorous route that would lead to a longer discussion. The 28 chapters are short; they offer exercises and worked examples, solved at the end of the book. Each part is supplemented with a relevant foreword and a useful summary including take-home messages. The editorial work is of good quality, with very few typographical errors. In spite of the title, kinetic theory stricto sensu is not the crux of the matter covered. The authors discuss the consequences of the molecular chaos assumption both at the individual particle level and in terms of collective behaviour. The first part of the book addresses the mechanics of grain collisions. It is emphasized that considering the coefficient of restitution ε -a central quantity governing the inelasticity of

  12. Granular materials flow like complex fluids

    Kou, Binquan; Cao, Yixin; Li, Jindong; Xia, Chengjie; Li, Zhifeng; Dong, Haipeng; Zhang, Ang; Zhang, Jie; Kob, Walter; Wang, Yujie

    2017-11-01

    Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they `relax', becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax

  13. Small-signal analysis of granular semiconductors

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey, E-mail: aapo.varpula@tkk.f [Department of Micro and Nanosciences, Aalto University, PO Box 13500, FI-00076 Aalto, Espoo (Finland)

    2010-11-01

    The small-signal ac response of granular n-type semiconductors is calculated analytically using the drift-diffusion theory when electronic trapping at grain boundaries is present. An electrical equivalent circuit (EEC) model of a granular n-type semiconductor is presented. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is very good in a broad frequency range at low dc bias voltages.

  14. Small-signal analysis of granular semiconductors

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey

    2010-01-01

    The small-signal ac response of granular n-type semiconductors is calculated analytically using the drift-diffusion theory when electronic trapping at grain boundaries is present. An electrical equivalent circuit (EEC) model of a granular n-type semiconductor is presented. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is very good in a broad frequency range at low dc bias voltages.

  15. Granular cell tumor: An uncommon benign neoplasm

    Tirthankar Gayen

    2015-01-01

    Full Text Available Granular cell tumor is a distinctly rare neoplasm of neural sheath origin. It mainly presents as a solitary asymptomatic swelling in the oral cavity, skin, and rarely internal organs in the middle age. Histopathology is characteristic, showing polyhedral cells containing numerous fine eosinophilic granules with indistinct cell margins. We present a case of granular cell tumor on the back of a 48-year-old woman which was painful, mimicking an adnexal tumor.

  16. A constitutive law for dense granular flows.

    Jop, Pierre; Forterre, Yoël; Pouliquen, Olivier

    2006-06-08

    A continuum description of granular flows would be of considerable help in predicting natural geophysical hazards or in designing industrial processes. However, the constitutive equations for dry granular flows, which govern how the material moves under shear, are still a matter of debate. One difficulty is that grains can behave like a solid (in a sand pile), a liquid (when poured from a silo) or a gas (when strongly agitated). For the two extreme regimes, constitutive equations have been proposed based on kinetic theory for collisional rapid flows, and soil mechanics for slow plastic flows. However, the intermediate dense regime, where the granular material flows like a liquid, still lacks a unified view and has motivated many studies over the past decade. The main characteristics of granular liquids are: a yield criterion (a critical shear stress below which flow is not possible) and a complex dependence on shear rate when flowing. In this sense, granular matter shares similarities with classical visco-plastic fluids such as Bingham fluids. Here we propose a new constitutive relation for dense granular flows, inspired by this analogy and recent numerical and experimental work. We then test our three-dimensional (3D) model through experiments on granular flows on a pile between rough sidewalls, in which a complex 3D flow pattern develops. We show that, without any fitting parameter, the model gives quantitative predictions for the flow shape and velocity profiles. Our results support the idea that a simple visco-plastic approach can quantitatively capture granular flow properties, and could serve as a basic tool for modelling more complex flows in geophysical or industrial applications.

  17. The therapeutic potential of the cerebellum in schizophrenia

    Krystal Lynn Parker

    2014-09-01

    Full Text Available The cognitive role of the cerebellum is critically tied to its distributed connections throughout the brain. Accumulating evidence from anatomical, structural and functional imaging, and lesion studies advocate a cognitive network involving indirect connections between the cerebellum and non-motor areas in the prefrontal cortex. Cerebellar stimulation dynamically influences activity in several regions of the frontal cortex and effectively improves cognition in schizophrenia. In this manuscript, we summarize current literature on the cingulocerebellar circuit and we introduce a method to interrogate this circuit combining opotogenetics, neuropharmacology, and electrophysiology in awake-behaving animals while minimizing incidental stimulation of neighboring cerebellar nuclei. We propose the novel hypothesis that optogenetic cerebellar stimulation can restore aberrant frontal activity and rescue impaired cognition in schizophrenia. We focus on how a known cognitive region in the frontal cortex, the anterior cingulate, is influenced by the cerebellum. This circuit is of particular interest because it has been confirmed using tracing studies, neuroimaging reveals its role in cognitive tasks, it is conserved from rodents to humans, and diseases such as schizophrenia and autism appear in its aberrancy. Novel tract tracing results presented here provide support for how these two areas communicate. The primary pathway involves a disynaptic connection between the cerebellar dentate nuclei and the anterior cingulate cortex. Secondarily, the pathway from cerebellar fastigial nuclei to the ventral tegmental area, which supplies dopamine to the prefrontal cortex, may play a role as schizophrenia characteristically involves dopamine deficiencies. We hope that the hypothesis described here will inspire new therapeutic strategies targeting currently untreatable cognitive impairments in schizophrenia.

  18. Linking Essential Tremor to the Cerebellum: Neuropathological Evidence.

    Louis, Elan D

    2016-06-01

    A fundamental question about essential tremor (ET) is whether its associated pathological changes and disease mechanisms are linkable to a specific brain region. To that end, recent tissue-based studies have made significant strides in elucidating changes in the ET brain. Emerging from these studies is increasing neuropathological evidence linking ET to the cerebellum. These studies have systematically identified a broad range of structural, degenerative changes in the ET cerebellum, spanning across all Purkinje cell compartments. These include the dendritic compartment (where there is an increase in number of Purkinje cell dendritic swellings, a pruning of the dendritic arbor, and a reduction in spine density), the cell body (where, aside from reductions in Purkinje cell linear density in some studies, there is an increase in the number of heterotopic Purkinje cell soma), and the axonal compartment (where a plethora of changes in axonal morphology have been observed, including an increase in the number of thickened axonal profiles, torpedoes, axonal recurrent collaterals, axonal branching, and terminal axonal sprouting). Additional changes, possibly due to secondary remodeling, have been observed in neighboring neuronal populations. These include a hypertrophy of basket cell axonal processes and changes in the distribution of climbing fiber-Purkinje cell synapses. These changes all distinguish ET from normal control brains. Initial studies further indicate that the profile (i.e., constellation) of these changes may separate ET from other diseases of the cerebellum, thereby serving as a disease signature. With the discovery of these changes, a new model of ET has arisen, which posits that it may be a neurodegenerative disorder centered in the cerebellar cortex. These newly emerging neuropathological studies pave the way for anatomically focused, hypothesis-driven, molecular mechanistic studies of disease pathogenesis.

  19. The human cerebellum: a review of physiologic neuroanatomy.

    Roostaei, Tina; Nazeri, Arash; Sahraian, Mohammad Ali; Minagar, Alireza

    2014-11-01

    The cerebellum resides in the posterior cranial fossa dorsal to the brainstem and has diverse connections to the cerebrum, brain stem, and spinal cord. It is anatomically and physiologically divided into distinct functional compartments and is composed of highly regular arrays of neuronal units, each sharing the same basic cerebellar microcircuitry. Its circuitry is critically involved in motor control and motor learning, and its role in nonmotor cognitive and affective functions is becoming increasingly recognized. This article describes the cerebellar gross and histologic neuroanatomy in relation to its function, and the relevance of cerebellar circuitry and firing patterns to motor learning. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. CDKL5 knockout leads to altered inhibitory transmission in the cerebellum of adult mice.

    Sivilia, S; Mangano, C; Beggiato, S; Giuliani, A; Torricella, R; Baldassarro, V A; Fernandez, M; Lorenzini, L; Giardino, L; Borelli, A C; Ferraro, L; Calzà, L

    2016-06-01

    Mutations in the X-linked cyclin-dependent kinase-like 5 gene (CDKL5) are associated to severe neurodevelopmental alterations including motor symptoms. In order to elucidate the neurobiological substrate of motor symptoms in CDKL5 syndrome, we investigated the motor function, GABA and glutamate pathways in the cerebellum of CDKL5 knockout female mice. Behavioural data indicate that CDKL5-KO mice displayed impaired motor coordination on the Rotarod test, and altered steps, as measured by the gait analysis using the CatWalk test. A higher reduction in spontaneous GABA efflux, than that in glutamate, was observed in CDKL5-KO mouse cerebellar synaptosomes, leading to a significant increase of spontaneous glutamate/GABA efflux ratio in these animals. On the contrary, there were no differences between groups in K(+) -evoked GABA and glutamate efflux. The anatomical analysis of cerebellar excitatory and inhibitory pathways showed a selective defect of the GABA-related marker GAD67 in the molecular layer in CDKL5-KO mice, while the glutamatergic marker VGLUT1 was unchanged in the same area. Fine cerebellar structural abnormalities such as a reduction of the inhibitory basket 'net' estimated volume and an increase of the pinceau estimated volume were also observed in CDKL5-KO mice. Finally, the BDNF mRNA expression level in the cerebellum, but not in the hippocampus, was reduced compared with WT animals. These data suggest that CDKL5 deletion during development more markedly impairs the establishment of a correct GABAergic cerebellar network than that of glutamatergic one, leading to the behavioural symptoms associated with CDKL5 mutation. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  1. Experimentally determined distribution of granular-flow characteristics in collisional bed load transport

    Matoušek Václav

    2018-01-01

    Full Text Available A series of laboratory experiments on turbulent open-channel two-phase flow in a form of intense bed load transport is reported. Measurements in a laboratory tilting flume included camera based imaging techniques to identify the structure of the flow at the local level. Obtained experimental distributions of two-phase flow related parameters - granular velocity, concentration, and temperature - across a collisional transport layer are discussed. The results are analysed together with additional measured quantities (discharges of mixture and grains, flow depth, bed slope etc. Our major goal is to evaluate the distribution of granular stresses across the transport layer with a special attention paid to the interface between the transport layer and the bed. Furthermore, comparisons are discussed between the experimental results and predictions produced by suitable kinetic-theory based models.

  2. Current Opinions and Areas of Consensus on the Role of the Cerebellum in Dystonia.

    Shakkottai, Vikram G; Batla, Amit; Bhatia, Kailash; Dauer, William T; Dresel, Christian; Niethammer, Martin; Eidelberg, David; Raike, Robert S; Smith, Yoland; Jinnah, H A; Hess, Ellen J; Meunier, Sabine; Hallett, Mark; Fremont, Rachel; Khodakhah, Kamran; LeDoux, Mark S; Popa, Traian; Gallea, Cécile; Lehericy, Stéphane; Bostan, Andreea C; Strick, Peter L

    2017-04-01

    A role for the cerebellum in causing ataxia, a disorder characterized by uncoordinated movement, is widely accepted. Recent work has suggested that alterations in activity, connectivity, and structure of the cerebellum are also associated with dystonia, a neurological disorder characterized by abnormal and sustained muscle contractions often leading to abnormal maintained postures. In this manuscript, the authors discuss their views on how the cerebellum may play a role in dystonia. The following topics are discussed: The relationships between neuronal/network dysfunctions and motor abnormalities in rodent models of dystonia. Data about brain structure, cerebellar metabolism, cerebellar connections, and noninvasive cerebellar stimulation that support (or not) a role for the cerebellum in human dystonia. Connections between the cerebellum and motor cortical and sub-cortical structures that could support a role for the cerebellum in dystonia. Overall points of consensus include: Neuronal dysfunction originating in the cerebellum can drive dystonic movements in rodent model systems. Imaging and neurophysiological studies in humans suggest that the cerebellum plays a role in the pathophysiology of dystonia, but do not provide conclusive evidence that the cerebellum is the primary or sole neuroanatomical site of origin.

  3. Microfluidics of soft granular gels

    Nixon, Ryan; Bhattacharjee, Tapomoy; Sawyer, W. Gregory; Angelini, Thomas E.

    Microfluidic methods for encapsulating cells and particles typically involve drop making with two immiscible fluids. The main materials constraint in this approach is surface tension, creating inherent instability between the two fluids. We can eliminate this instability by using miscible inner and outer phases. This is achieved by using granular micro gels which are chemically miscible but physically do not mix. These microgels are yield stress materials, so they flow as solid plugs far from shear gradients, and fluidize where gradients are generated - near an injection nozzle for example. We have found that tuning the yield stress of the material by varying polymer concentration, device performance can be controlled. The solid like behavior of the gel allows us to produces infinitely stable jets that maintain their integrity and configuration over long distances and times. These properties can be combined and manipulated to produce discrete particulate bunches of an inner phase, flowing inside of an outer phase, well enough even to print a Morse code message suspended within flow chambers about a millimeter in diameter moving at millimeters a second.

  4. COMPORTAMIENTO RESILIENTE DE MATERIALES GRANULARES EN PAVIMENTOS FLEXIBLES: ESTADO DEL CONOCIMIENTO RESILIENT BEHAVIOR OF GRANULAR MATERIALS IN FLEXIBLE PAVEMENTS: STATE OF THE ART

    Hugo Alexander Rondón Quintana

    2007-07-01

    Full Text Available Los vehículos que circulan sobre una estructura de pavimento inducen ciclos de carga y descarga que generan dentro de las capas granulares deformaciones recuperables (resilientes y permanentes (plásticas. La ingeniería de pavimentos ha venido desarrollando estudios desde la década de los 60 con el fin de intentar comprender el comportamiento elastoplástico que experimentan materiales granulares cuando conforman capas de base y subbase en estructuras flexibles. La mayor parte de las investigaciones que se han realizado en esta área se han concentrado en estudiar su comportamiento resiliente. El estado del conocimiento de estudios desarrollados para medir la respuesta resiliente y la deformación permanente en materiales granulares es presentado en dos artículos por separado. En este primer artículo se presenta la forma como ha sido estudiado el comportamiento resiliente de materiales granulares y se discuten los factores que influyen en dicho comportamiento. Al final del artículo se presenta la evolución de las ecuaciones matemáticas desarrolladas a partir de resultados de estudios teóricos y experimentales. Un estado del conocimiento sobre el fenómeno de deformación permanente es presentado en un segundo artículo.When vehicles move on a pavement structure, they induce load cycles that generate resilient and permanent strains inside granular layers. Since the 60's, pavement engineering has developed studies in order to understand the elasto-plastic behavior that granular materials experiment on base and sub-base layers of flexible pavements. Most of the researches that have been made in this area have concentrated in studying their resilient behavior. A state of the art about the behavior of granular materials in flexible pavements is presented in two separate papers. This first paper tries on resilient stress-strain characteristics of such materials. The mathematical equations found in the literature to predict the resilient

  5. Role of association cortices and cerebellum during motor consolidation process

    Nagata, Ken; Wright, David K.; Box, Georgia A.

    2008-01-01

    Positron emission tomography (PET) studies of cerebral circulation activated during the first (naive) and second (learned) visual-motor tasks were performed to confirm the hypothesis that activated brain regions are different before and after the motor work. Subjects were 30 normal healthy right-handed volunteers (av. age 21 y), who had the first 10 tasks of cursor tracing (regular tracing, rt), as rapidly and accurately as possible, along the given star features and then second 15 tasks of tracing with the cursor with inverse polarity (mirror tracing, mt). During the tasks, PET images were obtained at 7th and 9th rt, and 10 times (1st-15th) during mt, with the high-resolution positron camera (HEADTOME V) to measure the cerebral blood flow after intravenous 15 O-water and were processed into 3D for statistics. At the 1st mt (under the most unfamiliar condition), stimulated were the right frontal and supplementary motor areas and temporal lobe, bilateral centriciput lobe, anterior cingulated gyrus, and left cerebellum hemisphere. Under the learned condition (at 15th mt), the primary motor area, lingual gyrus, cuneus, anterior cuneus, occipital lobe involving posterior cingulated gyrus and left cerebellum hemisphere were activated. Thus the hypothesis above was confirmed: reconfirmation of the brain plasticity. (R.T.)

  6. The cerebellum: a new key structure in the navigation system

    Christelle eRochefort

    2013-03-01

    Full Text Available Early investigations of cerebellar function focused on motor learning, in particular on eyeblink conditioning and adaptation of the vestibulo-ocular reflex, and led to the general view that cerebellar Long Term Depression (LTD at parallel fiber-Purkinje cell synapses is the neural correlate of cerebellar motor learning. Thereafter, while the full complexity of cerebellar plasticities was being unraveled, cerebellar involvement in more cognitive tasks - including spatial navigation - was further investigated. However, cerebellar implication in spatial navigation remains a matter of debate because motor deficits frequently associated with cerebellar damage often prevent the dissociation between its role in spatial cognition from its implication in motor function. Here, we review recent findings from behavioral and electrophysiological analyses of cerebellar mutant mouse models, which show that the cerebellum might participate in the construction of hippocampal spatial representation map (i.e. place cells and thereby in goal-directed navigation. These recent advances in cerebellar research point toward a model in which computation from the cerebellum could be required for spatial representation and would involve the integration of multi-source self-motion information to: 1 transform the reference frame of vestibular signals and 2 distinguish between self- and externally-generated vestibular signals. We eventually present herein anatomical and functional connectivity data supporting a cerebello-hippocampal interaction. Whilst a direct cerebello-hippocampal projection has been suggested, recent investigations rather favor a multi-synaptic pathway involving posterior parietal and retrosplenial cortices, two regions critically involved in spatial navigation.

  7. Intrinsic connectivity networks within cerebellum and beyond in eating disorders.

    Amianto, F; D'Agata, F; Lavagnino, L; Caroppo, P; Abbate-Daga, G; Righi, D; Scarone, S; Bergui, M; Mortara, P; Fassino, S

    2013-10-01

    Cerebellum seems to have a role both in feeding behavior and emotion regulation; therefore, it is a region that warrants further neuroimaging studies in eating disorders, severe conditions that determine a significant impairment in the physical and psychological domain. The aim of this study was to examine the cerebellum intrinsic connectivity during functional magnetic resonance imaging resting state in anorexia nervosa (AN), bulimia nervosa (BN), and healthy controls (CN). Resting state brain activity was decomposed into intrinsic connectivity networks (ICNs) using group spatial independent component analysis on the resting blood oxygenation level dependent time courses of 12 AN, 12 BN, and 10 CN. We extracted the cerebellar ICN and compared it between groups. Intrinsic connectivity within the cerebellar network showed some common alterations in eating disordered compared to healthy subjects (e.g., a greater connectivity with insulae, vermis, and paravermis and a lesser connectivity with parietal lobe); AN and BN patients were characterized by some peculiar alterations in connectivity patterns (e.g., greater connectivity with the insulae in AN compared to BN, greater connectivity with anterior cingulate cortex in BN compared to AN). Our data are consistent with the presence of different alterations in the cerebellar network in AN and BN patients that could be related to psychopathologic dimensions of eating disorders.

  8. Linking Essential Tremor to the Cerebellum-Neuroimaging Evidence.

    Cerasa, Antonio; Quattrone, Aldo

    2016-06-01

    Essential tremor (ET) is the most common pathological tremor disorder in the world, and post-mortem evidence has shown that the cerebellum is the most consistent area of pathology in ET. In the last few years, advanced neuroimaging has tried to confirm this evidence. The aim of the present review is to discuss to what extent the evidence provided by this field of study may be generalised. We performed a systematic literature search combining the terms ET with the following keywords: MRI, VBM, MRS, DTI, fMRI, PET and SPECT. We summarised and discussed each study and placed the results in the context of existing knowledge regarding the cerebellar involvement in ET. A total of 51 neuroimaging studies met our search criteria, roughly divided into 19 structural and 32 functional studies. Despite clinical and methodological differences, both functional and structural imaging studies showed similar findings but without defining a clear topography of neurodegeneration. Indeed, the vast majority of studies found functional and structural abnormalities in several parts of the anterior and posterior cerebellar lobules, but it remains to be established to what degree these neural changes contribute to clinical symptoms of ET. Currently, advanced neuroimaging has confirmed the involvement of the cerebellum in pathophysiological processes of ET, although a high variability in results persists. For this reason, the translation of this knowledge into daily clinical practice is again partially limited, although new advanced multivariate neuroimaging approaches (machine-learning) are proving interesting changes of perspective.

  9. The Effect of Gallic Acid on Histopathologic Evaluation of Cerebellum in Valproic Acid-Induced Autism Animal Models

    Parvin Samimi

    2016-06-01

    Full Text Available Autism spectrum disorder (ASD is counted as a worldwide public health problem. The possible causes of ASD are reactive oxygen species and free radicals. So, this study is aimed to evaluate the effects of Gallic acid, as an effective antioxidant, on histopathologic disorder of the cerebellum in valproic acid-induced autism animal models. 30 pregnant female rats were randomly divided into 5 groups, including: control, autism (or VAP and experimental 1, 2 and 3. Using a gavage needle, Gallic acid administered orally until about2 months of age. After the end of the treatment period, the rats were anesthetized with ether and their cerebellar tissues were removed for histopathologic studies. A significant decrease in the number of Purkinje and granular cells was observed in this study in VAP group compared to the control group (P≤0.05. A trend toward improvement was observed in the groups received 100 and 200 mg/kg of Gallic acid (P≤0.05. The results of this research revealed that Gallic acid reduces the side effects caused by valproic acid on cerebellar tissue of autistic rats. So, it should be considered for therapeutic goals.

  10. Cerebellum: from Fundamentals to Translational Approaches. The Seventh International Symposium of the Society for Research on the Cerebellum.

    Manto, Mario; Mariën, Peter

    2016-02-01

    In terms of cerebellar research and ataxiology, a most fascinating period is currently going on. Numerous academic groups are now focusing their innovative research on the so-called little brain, hidden at the bottom of our brain. Indeed, its unique anatomical features make the cerebellum a wonderful window to address major questions about the central nervous system. The seventh international symposium of the SRC was held in Brussels at the Palace of Academies from May 8 to 10, 2015. The main goal of this dense symposium was to gather in a 2-day meeting senior researchers of exceptional scientific quality and talented junior scientists from all over the world working in the multidisciplinary field of cerebellar research. Fundamental and clinical researchers shared the latest knowledge and developments in this rapidly growing field. New ideas, addressed in a variety of inspiring talks, provoked a vivid debate. Advances in genetics, development, electrophysiology, neuroimaging, neurocognition and affect, as well as in the cerebellar ataxias and the controversies on the roles and functions of the cerebellum were presented. The Ferdinando Rossi lecture and the key-note lecture were delivered by Jan Voogd and Chris De Zeeuw, respectively. Contacts between researchers of different neuroscientific disciplines established a robust basis for novel trends and promising new cooperations between researchers and their centers spread all over the world.

  11. Granular Materials and Risks In ISRU

    Behringer, Robert P.; Wilkinson, R. Allen

    2004-01-01

    Working with soil, sand, powders, ores, cement and sintered bricks, excavating, grading construction sites, driving off-road, transporting granules in chutes and pipes, sifting gravel, separating solids from gases, and using hoppers are so routine that it seems straightforward to execute these operations on the Moon and Mars as we do on Earth. We discuss how little these processes are understood and point out the nature of trial-and-error practices that are used in today's massive over-design. Nevertheless, such designs have a high failure rate. Implementation and extensive incremental scaling up of industrial processes are routine because of the inadequate predictive tools for design. We present a number of pragmatic scenarios where granular materials play a role, the risks involved, what some of the basic issues are, and what understanding is needed to greatly reduce the risks. This talk will focus on a particular class of granular flow issues, those that pertain to dense materials, their physics, and the failure problems associated with them. In particular, key issues where basic predictability is lacking include stability of soils for the support of vehicles and facilities, ability to control the flow of dense materials (jamming and flooding/unjamming at the wrong time), the ability to predict stress profiles (hence create reliable designs) for containers such as bunkers or silos. In particular, stress fluctuations, which are not accounted for in standard granular design models, can be very large as granular materials flows, and one result is frequent catastrophic failure of granular devices.

  12. Collapse of tall granular columns in fluid

    Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves

    2017-06-01

    Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

  13. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

    Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M.E.; Zeltzer, G.; Do, H.; Yen, B.K.; Best, M.E.

    2001-01-01

    We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18 Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18 Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording

  14. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

    Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M. E.; Zeltzer, G.; Do, H.; Yen, B. K.; Best, M. E.

    2001-10-01

    We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording.

  15. Electronics and triggering challenges for the CMS High Granularity Calorimeter

    Lobanov, A.

    2018-02-01

    The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0.2 fC-10 pC), low noise (~2000 e- to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (~20 mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing the data from the HGCAL imposes equally large challenges on the off-detector electronics, both for the hardware and incorporated algorithms. We present an overview of the complete electronics architecture, as well as the performance of prototype components and algorithms.

  16. Electronics and triggering challenges for the CMS High Granularity Calorimeter

    Lobanov, Artur

    2017-01-01

    The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0-10 pC), low noise (~2000e- to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (~10mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing all the data from the HGCAL imposes equally large ch...

  17. Partitioning of fresh crude oil between floating, dispersed and sediment phases: Effect of exposure order to dispersant and granular materials.

    Boglaienko, Daria; Tansel, Berrin

    2016-06-15

    When three or more high and low energy substrates are mixed, wetting order can significantly affect the behavior of the mixture. We analyzed the phase distribution of fresh floating Louisiana crude oil into dispersed, settled and floating phases depending on the exposure sequence to Corexit 9500A (dispersant) and granular materials. In the experiments artificial sea water at salinity 34‰ was used. Limestone (2.00-0.300 mm) and quartz sand (0.300-0.075 mm) were used as the natural granular materials. Dispersant Corexit 9500A increased the amount of dispersed oil up to 33.76 ± 7.04%. Addition of granular materials after the dispersant increased dispersion of oil to 47.96 ± 1.96%. When solid particles were applied on the floating oil before the dispersant, oil was captured as oil-particle aggregates and removed from the floating layer. However, dispersant addition led to partial release of the captured oil, removing it from the aggregated form to the dispersed and floating phases. There was no visible oil aggregation with the granular materials when quartz or limestone was at the bottom of the flask before the addition of oil and dispersant. The results show that granular materials can be effective when applied from the surface for aggregating or dispersing oil. However, the granular materials in the sediments are not effective neither for aggregating nor dispersing floating oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Contact force structure and force chains in 3D sheared granular systems

    Mair, Karen; Jettestuen, Espen; Abe, Steffen

    2010-05-01

    Faults often exhibit accumulations of granular debris, ground up to create a layer of rock flour or fault gouge separating the rigid fault walls. Numerical simulations and laboratory experiments of sheared granular materials, suggest that applied loads are preferentially transmitted across such systems by transient force networks that carry enhanced forces. The characterisation of such features is important since their nature and persistence almost certainly influence the macroscopic mechanical stability of these systems and potentially that of natural faults. 3D numerical simulations of granular shear are a valuable investigation tool since they allow us to track individual particle motions, contact forces and their evolution during applied shear, that are difficult to view directly in laboratory experiments or natural fault zones. In characterising contact force distributions, it is important to use global structure measures that allow meaningful comparisons of granular systems having e.g. different grain size distributions, as may be expected at different stages of a fault's evolution. We therefore use a series of simple measures to characterise the structure, such as distributions and correlations of contact forces that can be mapped onto a force network percolation problem as recently proposed by Ostojic and coworkers for 2D granular systems. This allows the use of measures from percolation theory to both define and characterise the force networks. We demonstrate the application of this method to 3D simulations of a sheared granular material. Importantly, we then compare our measure of the contact force structure with macroscopic frictional behaviour measured at the boundaries of our model to determine the influence of the force networks on macroscopic mechanical stability.

  19. Shp2-Dependent ERK Signaling Is Essential for Induction of Bergmann Glia and Foliation of the Cerebellum

    Li, Kairong; Leung, Alan W.; Guo, Qiuxia; Yang, Wentian

    2014-01-01

    Folding of the cortex and the persistence of radial glia (RG)-like cells called Bergmann glia (BG) are hallmarks of the mammalian cerebellum. Similar to basal RG in the embryonic neocortex, BG maintain only basal processes and continuously express neural stem cell markers. Past studies had focused on the function of BG in granule cell migration and how granule cell progenitors (GCP) regulate cerebellar foliation. The molecular control of BG generation and its role in cerebellar foliation are less understood. Here, we have analyzed the function of the protein tyrosine phosphatase Shp2 in mice by deleting its gene Ptpn11 in the entire cerebellum or selectively in the GCP lineage. Deleting Ptpn11 in the entire cerebellum by En1-cre blocks transformation of RG into BG but preserves other major cerebellar cell types. In the absence of BG, inward invagination of GCP persists but is uncoupled from the folding of the Purkinje cell layer and the basement membrane, leading to disorganized lamination and an absence of cerebellar folia. In contrast, removing Ptpn11 in the GCP lineage by Atoh1-cre has no effect on cerebellar development, indicating that Shp2 is not cell autonomously required in GCP. Furthermore, we demonstrate that Ptpn11 interacts with Fgf8 and is essential for ERK activation in RG and nascent BG. Finally, expressing constitutively active MEK1 rescues BG formation and cerebellar foliation in Shp2-deficient cerebella. Our results demonstrate an essential role of Shp2 in BG specification via fibroblast growth factor/extracellular signal-regulated protein kinase signaling, and reveal a crucial function of BG in organizing cerebellar foliation. PMID:24431450

  20. Vygotsky Meets Neuroscience: The Cerebellum and the Rise of Culture through Play

    Vandervert, Larry

    2017-01-01

    The author suggests the brain's cerebellum and cerebral cortex are the origin of culture and considers the cerebellar models that came to constitute culture to be derived specifically from play. He summarizes recent research on the behavioral, cognitive, and affective evolution of the cerebellum and the cerebral cortex that shows the development…

  1. Evolutionary mechanisms that generate morphology and neural-circuit diversity of the cerebellum.

    Hibi, Masahiko; Matsuda, Koji; Takeuchi, Miki; Shimizu, Takashi; Murakami, Yasunori

    2017-05-01

    The cerebellum is derived from the dorsal part of the anterior-most hindbrain. The vertebrate cerebellum contains glutamatergic granule cells (GCs) and gamma-aminobutyric acid (GABA)ergic Purkinje cells (PCs). These cerebellar neurons are generated from neuronal progenitors or neural stem cells by mechanisms that are conserved among vertebrates. However, vertebrate cerebella are widely diverse with respect to their gross morphology and neural circuits. The cerebellum of cyclostomes, the basal vertebrates, has a negligible structure. Cartilaginous fishes have a cerebellum containing GCs, PCs, and deep cerebellar nuclei (DCNs), which include projection neurons. Ray-finned fish lack DCNs but have projection neurons termed eurydendroid cells (ECs) in the vicinity of the PCs. Among ray-finned fishes, the cerebellum of teleost zebrafish has a simple lobular structure, whereas that of weakly electric mormyrid fish is large and foliated. Amniotes, which include mammals, independently evolved a large, foliated cerebellum, which contains massive numbers of GCs and has functional connections with the dorsal telencephalon (neocortex). Recent studies of cyclostomes and cartilaginous fish suggest that the genetic program for cerebellum development was already encoded in the genome of ancestral vertebrates. In this review, we discuss how alterations of the genetic and cellular programs generated diversity of the cerebellum during evolution. © 2017 Japanese Society of Developmental Biologists.

  2. Interactions between Prefrontal Cortex and Cerebellum Revealed by Trace Eyelid Conditioning

    Kalmbach, Brian E.; Ohyama, Tatsuya; Kreider, Joy C.; Riusech, Frank; Mauk, Michael D.

    2009-01-01

    Eyelid conditioning has proven useful for analysis of learning and computation in the cerebellum. Two variants, delay and trace conditioning, differ only by the relative timing of the training stimuli. Despite the subtlety of this difference, trace eyelid conditioning is prevented by lesions of the cerebellum, hippocampus, or medial prefrontal…

  3. Wet granular matter a truly complex fluid

    Herminghaus, Stephan

    2013-01-01

    This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter and keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. Readership: For the young and advanced researcher entering the field of wet granular matter.

  4. 11th Traffic and Granular Flow Conference

    Daamen, Winnie

    2016-01-01

    The Conference on Traffic and Granular Flow brings together international researchers from different fields ranging from physics to computer science and engineering to discuss the latest developments in traffic-related systems. Originally conceived to facilitate new ideas by considering the similarities of traffic and granular flow, TGF'15, organised by Delft University of Technology, now covers a broad range of topics related to driven particle and transport systems. Besides the classical topics of granular flow and highway traffic, its scope includes data transport (Internet traffic), pedestrian and evacuation dynamics, intercellular transport, swarm behaviour and the collective dynamics of other biological systems. Recent advances in modelling, computer simulation and phenomenology are presented, and prospects for applications, for example to traffic control, are discussed. The conference explores the interrelations between the above-mentioned fields and offers the opportunity to stimulate interdisciplinar...

  5. Granular Silo collapse: an experimental study

    Clement, Eric; Gutierriez, Gustavo; Boltenhagen, Philippe; Lanuza, Jose

    2008-03-01

    We present an experimental work that develop some basic insight into the pre-buckling behavior and the buckling transition toward plastic collapse of a granular silo. We study different patterns of deformation generated on thin paper cylindrical shells during granular discharge. We study the collapse threshold for different bed height, flow rates and grain sizes. We compare the patterns that appear during the discharge of spherical beads, with those obtained in the axially compressed cylindrical shells. When the height of the granular column is close to the collapse threshold, we describe a ladder like pattern that rises around the cylinder surface in a spiral path of diamond shaped localizations, and develops into a plastic collapsing fold that grows around the collapsing silo.

  6. Statistical mechanics of dense granular media

    Coniglio, A; Fierro, A; Nicodemi, M; Ciamarra, M Pica; Tarzia, M

    2005-01-01

    We discuss some recent results on the statistical mechanics approach to dense granular media. In particular, by analytical mean field investigation we derive the phase diagram of monodisperse and bidisperse granular assemblies. We show that 'jamming' corresponds to a phase transition from a 'fluid' to a 'glassy' phase, observed when crystallization is avoided. The nature of such a 'glassy' phase turns out to be the same as found in mean field models for glass formers. This gives quantitative evidence for the idea of a unified description of the 'jamming' transition in granular media and thermal systems, such as glasses. We also discuss mixing/segregation transitions in binary mixtures and their connections to phase separation and 'geometric' effects

  7. Glioblastoma multiforme of the cerebellum: description of three cases.

    Luccarelli, G

    1980-01-01

    Only 43 cases of glioblastoma multiforme of the cerebellum have been reported in the literature. This report is based on the findings of 3 cerebellar glioblastomas in a review of 1,206 consecutive confirmed cases of glioblastoma operated on between 1947 and 1977 at the Istituto Neurologico of Milan, giving an incidence of 0.24%. Clinical features are similar to those of any other fast-growing subtentorial tumour. Neuroradiological studies, including CAT, are of little help in predicting the exact nature of these tumours before surgery. A correct diagnosis can be reached only by microscopic examination. Histological patterns appear in no way to differ from those of cerebral glioblastoma. The biological behaviour of these tumours is in all respects identical to that of glioblastoma of cerebral hemispheres.

  8. Wavelet analysis of MR functional data from the cerebellum

    Karen, Romero Sánchez; Vásquez Reyes Marcos, A.; González Gómez Dulce, I.; Hernández López, Javier M.; Silvia, Hidalgo Tobón; Pilar, Dies Suarez; Eduardo, Barragán Pérez; Benito, De Celis Alonso

    2014-01-01

    The main goal of this project was to create a computer algorithm based on wavelet analysis of BOLD signals, which automatically diagnosed ADHD using information from resting state MR experiments. Male right handed volunteers (infants with ages between 7 and 11 years old) were studied and compared with age matched controls. Wavelet analysis, which is a mathematical tool used to decompose time series into elementary constituents and detect hidden information, was applied here to the BOLD signal obtained from the cerebellum 8 region of all our volunteers. Statistical differences between the values of the a parameters of wavelet analysis was found and showed significant differences (p<0.02) between groups. This difference might help in the future to distinguish healthy from ADHD patients and therefore diagnose ADHD

  9. Wavelet analysis of MR functional data from the cerebellum

    Karen, Romero Sánchez, E-mail: alphacentauri-hp@hotmail.com, E-mail: marcos-vaquezr@hotmail.com, E-mail: isabeldgg@hotmail.com; Vásquez Reyes Marcos, A., E-mail: alphacentauri-hp@hotmail.com, E-mail: marcos-vaquezr@hotmail.com, E-mail: isabeldgg@hotmail.com; González Gómez Dulce, I., E-mail: alphacentauri-hp@hotmail.com, E-mail: marcos-vaquezr@hotmail.com, E-mail: isabeldgg@hotmail.com; Hernández López, Javier M., E-mail: javierh@fcfm.buap.mx [Faculty of Physics and Mathematics, BUAP, Puebla, Pue (Mexico); Silvia, Hidalgo Tobón, E-mail: shidbon@gmail.com [Infant Hospital of Mexico, Federico Gómez, Mexico DF. Mexico and Physics Department, Universidad Autónoma Metropolitana. Iztapalapa, Mexico DF. (Mexico); Pilar, Dies Suarez, E-mail: pilydies@yahoo.com, E-mail: neurodoc@prodigy.net.mx; Eduardo, Barragán Pérez, E-mail: pilydies@yahoo.com, E-mail: neurodoc@prodigy.net.mx [Infant Hospital of Mexico, Federico Gómez, Mexico DF. (Mexico); Benito, De Celis Alonso, E-mail: benileon@yahoo.com [Faculty of Physics and Mathematics, BUAP, Puebla, Pue. Mexico and Foundation for Development Carlos Sigüenza. Puebla, Pue. (Mexico)

    2014-11-07

    The main goal of this project was to create a computer algorithm based on wavelet analysis of BOLD signals, which automatically diagnosed ADHD using information from resting state MR experiments. Male right handed volunteers (infants with ages between 7 and 11 years old) were studied and compared with age matched controls. Wavelet analysis, which is a mathematical tool used to decompose time series into elementary constituents and detect hidden information, was applied here to the BOLD signal obtained from the cerebellum 8 region of all our volunteers. Statistical differences between the values of the a parameters of wavelet analysis was found and showed significant differences (p<0.02) between groups. This difference might help in the future to distinguish healthy from ADHD patients and therefore diagnose ADHD.

  10. Controlling mixing and segregation in time periodic granular flows

    Bhattacharya, Tathagata

    Segregation is a major problem for many solids processing industries. Differences in particle size or density can lead to flow-induced segregation. In the present work, we employ the discrete element method (DEM)---one type of particle dynamics (PD) technique---to investigate the mixing and segregation of granular material in some prototypical solid handling devices, such as a rotating drum and chute. In DEM, one calculates the trajectories of individual particles based on Newton's laws of motion by employing suitable contact force models and a collision detection algorithm. Recently, it has been suggested that segregation in particle mixers can be thwarted if the particle flow is inverted at a rate above a critical forcing frequency. Further, it has been hypothesized that, for a rotating drum, the effectiveness of this technique can be linked to the probability distribution of the number of times a particle passes through the flowing layer per rotation of the drum. In the first portion of this work, various configurations of solid mixers are numerically and experimentally studied to investigate the conditions for improved mixing in light of these hypotheses. Besides rotating drums, many studies of granular flow have focused on gravity driven chute flows owing to its practical importance in granular transportation and to the fact that the relative simplicity of this type of flow allows for development and testing of new theories. In this part of the work, we observe the deposition behavior of both mono-sized and polydisperse dry granular materials in an inclined chute flow. The effects of different parameters such as chute angle, particle size, falling height and charge amount on the mass fraction distribution of granular materials after deposition are investigated. The simulation results obtained using DEM are compared with the experimental findings and a high degree of agreement is observed. Tuning of the underlying contact force parameters allows the achievement

  11. 76 FR 8774 - Granular Polytetrafluoroethylene Resin From Japan

    2011-02-15

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-386 (Third Review)] Granular Polytetrafluoroethylene Resin From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five... revocation of the antidumping duty order on granular polytetrafluoroethylene resin from Japan would be likely...

  12. Cerebellum and cognition in multiple sclerosis: the fall status matters.

    Kalron, Alon; Allali, Gilles; Achiron, Anat

    2018-04-01

    Cerebellar volume has been linked with cognitive performances in MS; however, the association in terms of fall status has never been compared. Therefore, the objective of the current study was to compare cognitive performance with cerebellar volume between MS fallers and non-fallers. The cross-sectional study included 140 PwMS (96 women). MRI volumetric analysis was based on the FreeSurfer image analysis suite. Volumes of the cerebellar gray and white matter were identified as the region of interest. Cognitive function included scores obtained from a computerized cognitive battery of tests. The sample was divided into fallers and non-fallers. MS fallers demonstrated a lower global cognitive performance and reduced gray and white matter cerebellar volumes compared to non-fallers. A significant association was found between total gray and white matter cerebellar volume and visual spatial subdomain (P value = 0.044 and 0.032, respectively) in the non-fallers group. The association remained significant after controlling for the total cranial volume and neurological disability (P value = 0.026 and 0.047, respectively). A relationship was found between the visual spatial score and the left gray matter cerebellum volume; R 2  = 0.44, P value = 0.021. We believe that a unique relationship exists between the cerebellum structure and cognitive processing according to fall history in PwMS and should be considered when investigating the association between brain functioning and cognitive performances in MS.

  13. CEREBELLUM: LINKS BETWEEN DEVELOPMENT, DEVELOPMENTAL DISORDERS AND MOTOR LEARNING

    Mario U Manto

    2012-01-01

    Full Text Available The study of the links and interactions between development and motor learning has noticeable implications for the understanding and management of neurodevelopmental disorders. This is particularly relevant for the cerebellum which is critical for sensorimotor learning. The olivocerebellar pathway is a key pathway contributing to learning of motor skills. Its developmental maturation and remodelling are being unravelled. Advances in genetics have led to major improvements in our appraisal of the genes involved in cerebellar development, especially studies in mutant mice. Cerebellar neurogenesis is compartmentalized in relationship with neurotransmitter fate. The Engrailed-2 gene is a major actor of the specification of cerebellar cell types and late embryogenic morphogenesis. Math1, expressed by the rhombic lip (RL, is required for the genesis of glutamatergic neurons. Mutants deficient for the transcription factor Ptf1a display a lack of Purkinje cells and gabaergic interneurons. Rora gene contributes to the developmental signalling between granule cells and Purkinje neurons. The expression profile of SHH (Sonic hedgehog in postnatal stages determines the final size/shape of the cerebellum. Genes affecting the development impact upon the physiological properties of the cerebellar circuits. For instance, receptors are developmentally regulated and their action interferes directly with developmental processes. Another field of research which is expanding relates to very preterm neonates. They are at risk for cerebellar lesions, which may themselves impair the developmental events. Very preterm neonates often show sensori-motor deficits, highlighting another major link between impaired development and learning deficiencies. Pathways playing a critical role in cerebellar development are likely to become therapeutical targets for several neurodevelopmental disorders.

  14. Surface instabilities in shock loaded granular media

    Kandan, K.; Khaderi, S. N.; Wadley, H. N. G.; Deshpande, V. S.

    2017-12-01

    The initiation and growth of instabilities in granular materials loaded by air shock waves are investigated via shock-tube experiments and numerical calculations. Three types of granular media, dry sand, water-saturated sand and a granular solid comprising PTFE spheres were experimentally investigated by air shock loading slugs of these materials in a transparent shock tube. Under all shock pressures considered here, the free-standing dry sand slugs remained stable while the shock loaded surface of the water-saturated sand slug became unstable resulting in mixing of the shocked air and the granular material. By contrast, the PTFE slugs were stable at low pressures but displayed instabilities similar to the water-saturated sand slugs at higher shock pressures. The distal surfaces of the slugs remained stable under all conditions considered here. Eulerian fluid/solid interaction calculations, with the granular material modelled as a Drucker-Prager solid, reproduced the onset of the instabilities as seen in the experiments to a high level of accuracy. These calculations showed that the shock pressures to initiate instabilities increased with increasing material friction and decreasing yield strain. Moreover, the high Atwood number for this problem implied that fluid/solid interaction effects were small, and the initiation of the instability is adequately captured by directly applying a pressure on the slug surface. Lagrangian calculations with the directly applied pressures demonstrated that the instability was caused by spatial pressure gradients created by initial surface perturbations. Surface instabilities are also shown to exist in shock loaded rear-supported granular slugs: these experiments and calculations are used to infer the velocity that free-standing slugs need to acquire to initiate instabilities on their front surfaces. The results presented here, while in an idealised one-dimensional setting, provide physical understanding of the conditions required to

  15. Study of the granular electromagnetic calorimeter with PPDs and scintillator strips for ILC

    Kotera, Katsushige, E-mail: coterra@azusa.shinshu-u.ac.j [Shinshu University, Asahi 3-1-1, Matsumoto 390-8621 (Japan)

    2011-02-01

    A prototype module of a fine-granular electromagnetic calorimeter has been constructed by the CALICE collaboration and tested in the period August-September 2008 at the FNAL meson beam test facility. The calorimeter is one of the proposed concepts for a highly granular electromagnetic calorimeter for the International Linear Collider (ILC) experiment, which is designed to have an effective 10 mmx10 mm lateral segmentation using 10 mmx45 mm scintillator strips. The strips in the 15 odd layers are orthogonal with respect to those in the 15 even layers. A total of 2160 strip scintillators are individually read out using a Pixelated Photon Detector (PPD) or MPPC. As a preliminary result of the first stage analysis, we obtain a relative energy resolution for single electrons of {sigma}{sub E}/E=(15.15{+-}0.03)%/{radical}(E{sub beam}(GeV))+(1.44{+-}0.02)%, the quoted uncertainties are purely statistical.

  16. Magnetism and magnetoresistance from different origins in Co/ZnO:Al granular films

    Quan, Zhiyong, E-mail: quanzy@sxnu.edu.cn; Liu, Xia; Song, Zhilin; Xu, Xiaohong, E-mail: xuxh@dns.sxnu.edu.cn

    2016-12-01

    Co/ZnO:Al granular films were made on glass substrates by sequential magnetron sputter deposition of ultrathin Co layer and ZnO:Al layer at room temperature. The as-deposited films consist of superparamagnetic Co particles dispersed in ZnO:Al (~2% Al) semiconductor matrix. Distinguished magnetoresistance effect at room temperature was obtained in the as-deposited films, which obviously reduced after annealing due to the growth of Co particles. The size of important magnetic particles was analyzed by Langevin function for hysteresis loops and magnetoresistance curves at room temperature. It was found that small magnetic particle contribute to magnetoresistance behavior and large particles dominate the room temperature magnetism in Co/ZnO:Al granular films.

  17. Comparison and analysis of membrane fouling between flocculent sludge membrane bioreactor and granular sludge membrane bioreactor.

    Wang Jing-Feng

    Full Text Available The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs, two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates.

  18. Anaerobic granular sludge and biofilm reactors

    Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye

    2003-01-01

    by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

  19. Anisotropy in cohesive, frictional granular media

    Luding, Stefan

    2005-01-01

    The modelling of cohesive, frictional granular materials with a discrete particle molecular dynamics is reviewed. From the structure of the quasi-static granular solid, the fabric, stress, and stiffness tensors are determined, including both normal and tangential forces. The influence of the material properties on the flow behaviour is also reported, including relations between the microscopic attractive force and the macroscopic cohesion as well as the dependence of the macroscopic friction on the microscopic contact friction coefficient. Related to the dynamics, the anisotropy of both structure and stress are exponentially approaching the maximum

  20. International Workshop on Traffic and Granular Flow

    Herrmann, Hans; Schreckenberg, Michael; Wolf, Dietrich; Social, Traffic and Granular Dynamics

    2000-01-01

    "Are there common phenomena and laws in the dynamic behavior of granular materials, traffic, and socio-economic systems?" The answers given at the international workshop "Traffic and Granular Flow '99" are presented in this volume. From a physical standpoint, all these systems can be treated as (self)-driven many-particle systems with strong fluctuations, showing multistability, phase transitions, non-linear waves, etc. The great interest in these systems is due to several unexpected new discoveries and their practical relevance for solving some fundamental problems of today's societies. This includes intelligent measures for traffic flow optimization and methods from "econophysics" for stabilizing (stock) markets.

  1. Granular contact dynamics using mathematical programming methods

    Krabbenhoft, K.; Lyamin, A. V.; Huang, J.

    2012-01-01

    granular contact dynamics formulation uses an implicit time discretization, thus allowing for large time steps. Moreover, in the limit of an infinite time step, the general dynamic formulation reduces to a static formulation that is useful in simulating common quasi-static problems such as triaxial tests...... is developed and it is concluded that the associated sliding rule, in the context of granular contact dynamics, may be viewed as an artifact of the time discretization and that the use of an associated flow rule at the particle scale level generally is physically acceptable. (C) 2012 Elsevier Ltd. All rights...

  2. Tracing Thermal Creep Through Granular Media

    Steinpilz, Tobias; Teiser, Jens; Koester, Marc; Schywek, Mathias; Wurm, Gerhard

    2017-08-01

    A temperature gradient within a granular medium at low ambient pressure drives a gas flow through the medium by thermal creep. We measured the resulting air flow for a sample of glass beads with particle diameters between 290 μ m and 420 μ m for random close packing. Ambient pressure was varied between 1 Pa and 1000 Pa. The gas flow was quantified by means of tracer particles during parabolic flights. The flow varies systematically with pressure between 0.2 cm/s and 6 cm/s. The measured flow velocities are in quantitative agreement to model calculations that treat the granular medium as a collection of linear capillaries.

  3. Granular cells Tumor in the gastrointestinal tract

    Castano LL, Rodrigo; Gaitan B, Maria H; Juliao E, Fabian

    2005-01-01

    Granular cells tumors are ubiquitous lesions in the gastrointestinal tract, are rare and asymptomatic and they are generally an incidental discovery at gastroduodenoscopy or colonoscopy. In the gastrointestinal tract they are more frequently located in the esophagus, right colon and rectum, stomach, appendix, small intestine or biliopancreatic tract. This article describes three patients with four tumors of granular cells in rectum, esophagus (2 lesions) and appendix. It becomes special emphasis in their neural origin, their benign behavior that justifies the endoscopic resections or limited surgical excisions and the necessity of a pursuit for the possibility, although little, of malignant transformation

  4. The cerebellum and visual perceptual learning: evidence from a motion extrapolation task.

    Deluca, Cristina; Golzar, Ashkan; Santandrea, Elisa; Lo Gerfo, Emanuele; Eštočinová, Jana; Moretto, Giuseppe; Fiaschi, Antonio; Panzeri, Marta; Mariotti, Caterina; Tinazzi, Michele; Chelazzi, Leonardo

    2014-09-01

    Visual perceptual learning is widely assumed to reflect plastic changes occurring along the cerebro-cortical visual pathways, including at the earliest stages of processing, though increasing evidence indicates that higher-level brain areas are also involved. Here we addressed the possibility that the cerebellum plays an important role in visual perceptual learning. Within the realm of motor control, the cerebellum supports learning of new skills and recalibration of motor commands when movement execution is consistently perturbed (adaptation). Growing evidence indicates that the cerebellum is also involved in cognition and mediates forms of cognitive learning. Therefore, the obvious question arises whether the cerebellum might play a similar role in learning and adaptation within the perceptual domain. We explored a possible deficit in visual perceptual learning (and adaptation) in patients with cerebellar damage using variants of a novel motion extrapolation, psychophysical paradigm. Compared to their age- and gender-matched controls, patients with focal damage to the posterior (but not the anterior) cerebellum showed strongly diminished learning, in terms of both rate and amount of improvement over time. Consistent with a double-dissociation pattern, patients with focal damage to the anterior cerebellum instead showed more severe clinical motor deficits, indicative of a distinct role of the anterior cerebellum in the motor domain. The collected evidence demonstrates that a pure form of slow-incremental visual perceptual learning is crucially dependent on the intact cerebellum, bearing the notion that the human cerebellum acts as a learning device for motor, cognitive and perceptual functions. We interpret the deficit in terms of an inability to fine-tune predictive models of the incoming flow of visual perceptual input over time. Moreover, our results suggest a strong dissociation between the role of different portions of the cerebellum in motor versus

  5. Terminal velocity of liquids and granular materials dispersed by a high explosive

    Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

    2018-04-01

    The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass (M/C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/C ratio, with larger M/C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

  6. Terminal velocity of liquids and granular materials dispersed by a high explosive

    Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

    2018-05-01

    The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass ( M/ C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/ C ratio, with larger M/ C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

  7. Size invariance of the granular Rayleigh-Taylor instability.

    Vinningland, Jan Ludvig; Johnsen, Øistein; Flekkøy, Eirik G; Toussaint, Renaud; Måløy, Knut Jørgen

    2010-04-01

    The size scaling behavior of the granular Rayleigh-Taylor instability [J. L. Vinningland, Phys. Rev. Lett. 99, 048001 (2007)] is investigated experimentally, numerically, and theoretically. An upper layer of grains displaces a lower gap of air by organizing into dense fingers of falling grains separated by rising bubbles of air. The dependence of these structures on the system and grain sizes is investigated. A spatial measurement of the finger structures is obtained by the Fourier power spectrum of the wave number k. As the size of the grains increases the wave number decreases accordingly which leaves the dimensionless product of wave number and grain diameter, dk, invariant. A theoretical interpretation of the invariance, based on the scaling properties of the model equations, suggests a gradual breakdown of the invariance for grains smaller than approximately 70 microm or greater than approximately 570 microm in diameter.

  8. Advances in studies of dense volcanic granular flows

    Bursik, M [University of Buffalo, SUNY, Buffalo, NY 14260 (United States); Patra, A [University of Buffalo, SUNY, Buffalo, NY 14260 (United States); Pitman, E B [University of Buffalo, SUNY, Buffalo, NY 14260 (United States); Nichita, C [University of Buffalo, SUNY, Buffalo, NY 14260 (United States); Macias, J L [Universidad Nacional Autonoma de Mexico, Coyoacan, Mexico D F (Mexico); Saucedo, R [Universidad Nacional Autonoma de Mexico, Coyoacan, Mexico D F (Mexico); Girina, O [Institute of Volcanic Geology and Geochemistry, Russian Academy of Sciences, Petropavlovsk-Kamchatskii (Russian Federation)

    2005-02-01

    The collapse and decrepitation of a lava dome at the summit of a volcano generally results in the generation of dense granular flows, often referred to as block and ash flows. As the dome particles propagate from the source, they break apart by internal pressure as well as collision. The propagation of block and ash flows can be simulated to some accuracy with a depth averaged numerical model of the equations of continuity and momentum for a material with a frictional resistance. However, important features of such flows, such as the influence of remote stress through force chains, erosion of the volcano substrate, and shock formation and pressurization upon particle break up are poorly understood. In the near future, the influence of these factors will be incorporated into depth averaged models. Various numerical techniques based on particles will some day yield results that can be compared not only with bulk flow properties, but to the internal layering of block and ash flow deposits.

  9. Flow of Dense Granular Suspensions on an Inclined Plane

    Bonnoit, C.; Lanuza, J.; Lindner, A.; Clément, E.

    2008-07-01

    We investigate the flow behavior of dense granular suspensions, by the use of an inclined plane. The suspensions are prepared at high packing fractions and consist of spherical non-Brownian particles density matched with the suspending fluid. On the inclined plane, we perform a systematic study of the surface velocity as a function of the layer thickness for various flow rates and tilt angles. We perform measurements on a classical rheometer (parallel-plate rheometer) that is shown to be in good agreement with existing models, up to a volume fraction of 50%. Comparing these results, we show that the flow on an inclined plane can, up to a volume fraction of 50%, indeed be described by a purely viscous model in agreement with the results from classical rheometry.

  10. Evaluation of the relative biological effectiveness of carbon ion beams in the cerebellum using the rat organotypic slice culture system

    Yoshida, Yukari; Katoh, Hiroyuki; Nakano, Takashi; Suzuki, Yoshiyuki; Al-Jahdari, Wael S.; Shirai, Katsuyuki; Hamada, Nobuyuki; Funayama, Tomoo; Sakashita, Tetsuya; Kobayashi, Yasuhiko

    2012-01-01

    The purpose of this study was to clarify the relative biological effectiveness (RBE) values of carbon ion (C) beams in normal brain tissues, a rat organotypic slice culture system was used. The cerebellum was dissected from 10-day-old Wistar rats, cut parasagittally into approximately 600-μm-thick slices and cultivated using a membrane-based culture system with a liquid-air interface. Slices were irradiated with 140 kV X-rays and 18.3 MeV/amu C-beams (linear energy transfer=108 keV/μm). After irradiation, the slices were evaluated histopathologically using hematoxylin and eosin staining, and apoptosis was quantified using the TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay. Disorganization of the external granule cell layer (EGL) and apoptosis of the external granule cells (EGCs) were induced within 24 h after exposure to doses of more than 5 Gy from C-beams and X-rays. In the early postnatal cerebellum, morphological changes following exposure to C-beams were similar to those following exposure to X-rays. The RBEs values of C-beams using the EGL disorganization and the EGC TUNEL index endpoints ranged from 1.4 to 1.5. This system represents a useful model for assaying the biological effects of radiation on the brain, especially physiological and time-dependent phenomena. (author)

  11. Experiments and characterization of low-frequency oscillations in a granular column

    Oyarte Gálvez, Loreto; Rivas, Nicolás; van der Meer, Devaraj

    2018-04-01

    The behavior of a vertically vibrated granular bed is reminiscent of a liquid in that it exhibits many phenomena such as convection and Faraday-like surface waves. However, when the lateral dimensions of the bed are confined such that a quasi-one-dimensional geometry is formed, the only phenomena that remain are bouncing bed and the granular Leidenfrost effect. This permits the observation of the granular Leidenfrost state for a wide range of energy injection parameters and more specifically allows for a thorough characterization of the low-frequency oscillation (LFO) that is present in this state. In both experiments and particle simulations we determine the LFO frequency from the power spectral density of the center-of-mass signal of the grains, varying the amplitude and frequency of the driving, the particle diameter, and the number of layers in the system. We thus find that the LFO frequency (i) is inversely proportional to the fast inertial timescale and (ii) decorrelates with a typical decay time proportional to the slow dissipative timescale in the system. The latter is consistent with the view that the LFO is driven by the inherent noise that is present in the granular Leidenfrost state with a low number of particles.

  12. Granular Gas in a Periodic Lattice

    Dorbolo, S.; Brandenbourger, M.; Damanet, F.; Dister, H.; Ludewig, F.; Terwagne, D.; Lumay, G.; Vandewalle, N.

    2011-01-01

    Glass beads are placed in the compartments of a horizontal square grid. This grid is then vertically shaken. According to the reduced acceleration [image omitted] of the system, the granular material exhibits various behaviours. By counting the number of beads in each compartment after shaking, it is possible to define three regimes. At low…

  13. Pion showers in highly granular calorimeters

    New results on properties of hadron showers created by pion beam at 8–80 GeV in high granular electromagnetic and hadron calorimeters are presented. Data were used for the first time to investigate the separation of the neutral and charged hadron showers. The result is important to verify the prediction of the PFA ...

  14. Anomalous infrared absorption in granular superconductors

    Carr, G.L.; Garland, J.C.; Tanner, D.B.

    1983-01-01

    Granular superconductors are shown to have a far-infrared absorption that is larger when the samples are superconducting than when they are normal. By constrast, theoretical models for these materials predict that when the samples become superconducting, the absorption should decrease

  15. Vortex jamming in superconductors and granular rheology

    Yoshino, Hajime; Nogawa, Tomoaki; Kim, Bongsoo

    2009-01-01

    We demonstrate that a highly frustrated anisotropic Josephson junction array (JJA) on a square lattice exhibits a zero-temperature jamming transition, which shares much in common with those in granular systems. Anisotropy of the Josephson couplings along the horizontal and vertical directions plays roles similar to normal load or density in granular systems. We studied numerically static and dynamic response of the system against shear, i.e. injection of external electric current at zero temperature. Current-voltage curves at various strength of the anisotropy exhibit universal scaling features around the jamming point much as do the flow curves in granular rheology, shear-stress versus shear-rate. It turns out that at zero temperature the jamming transition occurs right at the isotropic coupling and anisotropic JJA behaves as exotic fragile vortex matter: it behaves as a superconductor (vortex glass) in one direction, whereas it is a normal conductor (vortex liquid) in the other direction even at zero temperature. Furthermore, we find a variant of the theoretical model for the anisotropic JJA quantitatively reproduces universal master flow-curves of the granular systems. Our results suggest an unexpected common paradigm stretching over seemingly unrelated fields-the rheology of soft materials and superconductivity.

  16. Random packing of colloids and granular matter

    Wouterse, A.

    2008-01-01

    This thesis deals with the random packing of colloids and granular matter. A random packing is a stable disordered collection of touching particles, without long-range positional and orientational order. Experimental random packings of particles with the same shape but made of different materials

  17. Deposition and shaking of dry granular piles

    Hasan, M.

    2003-01-01

    A friction force model describing reversible stick-slip transition during contact has been developed with the special purpose to simulate the deposition of granular material. A test with a mass on a conveyor belt kept in position by a spring shows that a numerical simulation of the dynamics of such

  18. ENGINEERING BULLETIN: GRANULAR ACTIVATED CARBON TREATMENT

    Granular activated carbon (GAC) treatment is a physicochemical process that removes a wide variety of contaminants by adsorbing them from liquid and gas streams [1, p. 6-3]. This treatment is most commonly used to separate organic contaminants from water or air; however, it can b...

  19. Velocity distributions in dilute granular systems

    van Zon, J.S.; Mac Kintosh, F.C.

    2005-01-01

    We investigate the idea that velocity distributions in granular gases are determined mainly by η, the coefficient of restitution and q, which measures the relative importance of heating (or energy input) to collisions. To this end, we study by numerical simulation the properties of inelastic gases

  20. Granular cell tumour of the urinary bladder

    Christoph von Klot

    2012-04-01

    Full Text Available With only 16 cases reported in the literature, the mostly benign granular cell tumour of the urinary bladder is exceptionally rare. We present the case of a 68-year old patient with one of these lesions demonstrating our histological findings including several immunohistochemical stainings used to differentiate between other more common entities.

  1. Nonlinear coherent structures in granular crystals

    Chong, C.; Porter, Mason A.; Kevrekidis, P. G.; Daraio, C.

    2017-10-01

    The study of granular crystals, which are nonlinear metamaterials that consist of closely packed arrays of particles that interact elastically, is a vibrant area of research that combines ideas from disciplines such as materials science, nonlinear dynamics, and condensed-matter physics. Granular crystals exploit geometrical nonlinearities in their constitutive microstructure to produce properties (such as tunability and energy localization) that are not conventional to engineering materials and linear devices. In this topical review, we focus on recent experimental, computational, and theoretical results on nonlinear coherent structures in granular crystals. Such structures—which include traveling solitary waves, dispersive shock waves, and discrete breathers—have fascinating dynamics, including a diversity of both transient features and robust, long-lived patterns that emerge from broad classes of initial data. In our review, we primarily discuss phenomena in one-dimensional crystals, as most research to date has focused on such scenarios, but we also present some extensions to two-dimensional settings. Throughout the review, we highlight open problems and discuss a variety of potential engineering applications that arise from the rich dynamic response of granular crystals.

  2. The critical current of granular superconductor

    Ignat'ev, V.K.

    1998-01-01

    A mechanism of hyper vortex pinning in granular superconductors is proposed to describe the field dependence of the critical current density and pinning potential. The results are in a good agreement with the experiment. The model represents the peak effect and the percolation mechanism of conductivity in ceramic superconductors

  3. The Contribution of the Cerebellum in the Hierarchial Development of the Self.

    Ceylan, Mehmet Emin; Dönmez, Aslıhan; Ülsalver, Barış Önen

    2015-12-01

    What distinguishes human beings from other living organisms is that a human perceives himself as a "self". The self is developed hierarchially in a multi-layered process, which is based on the evolutionary maturation of the nervous system and patterns according to the rules and demands of the external world. Many researchers have attempted to explain the different aspects of the self, as well as the related neural substrates. In this paper, we first review the previously proposed ideas regarding the neurobiology of the self. We then suggest a new hypothesis regarding the hierarchial self, which proposes that the self is developed at three stages: subjective, objective, and reflective selves. In the second part, we attempt to answer the question "Why do we need a self?" We therefore explain that different parts of the self developed in an effort to identify stability in space, stability against constantly changing objects, and stability against changing cognitions. Finally, we discuss the role of the cerebellum as the neural substrate for the self.

  4. Radiation induced cerebellum impairments in Swiss albino mice and its modulation by dietary Prunus domestica

    Sharma, Garima; Sisodia, Rashmi

    2012-01-01

    To study the biochemical, quantitative histopathological and behavioural changes after 5 Gy whole body irradiation and its modulation by supplementation of Prunus domestica extract (PDE) for 15 consecutive days on male Swiss albino. For this study healthy mice from an inbred colony were divided into five groups: (i) Control; (ii) PDE treated - mice in this group were orally supplemented with PDE (400 mg/kg body weight (bw)/day) once daily for 15 consecutive days; (iii) Irradiated-mice were whole body exposed to 5 Gy irradiated; (iv) PDE + irradiated-mice in this group were orally supplemented PDE for 15 days (once a day) prior to irradiation; and (v) irradiated+PDE -mice in this group were administered PDE orally for 15 days (once a day) consequently after irradiation. Marked radiation induced changes in the amount of cerebellar lipid peroxidation (LPO), glutathione (GSH), protein, superoxide dismutase (SOD), catalase and histopathological changes (molecular layer, granular layer and purkinje cell numbers) could be significantly ameliorated supplementation of PDE prior/post irradiation. Radiation induced deficits in learning and memory were also significantly ameliorated. PDE was found to have strong radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and also showed in vitro radioprotective activity. The result of present study showed that prior/post-supplementation of Prunus domestica has radioprotective potential as well as neuroprotective properties against the radiation. (author)

  5. Emotion and Theory of Mind in Schizophrenia-Investigating the Role of the Cerebellum.

    Mothersill, Omar; Knee-Zaska, Charlotte; Donohoe, Gary

    2016-06-01

    Social cognitive dysfunction, including deficits in facial emotion recognition and theory of mind, is a core feature of schizophrenia and more strongly predicts functional outcome than neurocognition alone. Although traditionally considered to play an important role in motor coordination, the cerebellum has been suggested to play a role in emotion processing and theory of mind, and also shows structural and functional abnormalities in schizophrenia. The aim of this systematic review was to investigate the specific role of the cerebellum in emotion and theory of mind deficits in schizophrenia using previously published functional neuroimaging studies. PubMed and PsycINFO were used to search for all functional neuroimaging studies reporting altered cerebellum activity in schizophrenia patients during emotion processing or theory of mind tasks, published until December 2014. Overall, 14 functional neuroimaging studies were retrieved. Most emotion studies reported lower cerebellum activity in schizophrenia patients relative to healthy controls. In contrast, the theory of mind studies reported mixed findings. Altered activity was observed across several posterior cerebellar regions involved in emotion and cognition. Weaker cerebellum activity in schizophrenia patients relative to healthy controls during emotion processing may contribute to blunted affect and reduced ability to recognise emotion in others. This research could be expanded by examining the relationship between cerebellum function, symptomatology and behaviour, and examining cerebellum functional connectivity in patients during emotion and theory of mind tasks.

  6. The organization of the human cerebellum estimated by intrinsic functional connectivity

    Krienen, Fenna M.; Castellanos, Angela; Diaz, Julio C.; Yeo, B. T. Thomas

    2011-01-01

    The cerebral cortex communicates with the cerebellum via polysynaptic circuits. Separate regions of the cerebellum are connected to distinct cerebral areas, forming a complex topography. In this study we explored the organization of cerebrocerebellar circuits in the human using resting-state functional connectivity MRI (fcMRI). Data from 1,000 subjects were registered using nonlinear deformation of the cerebellum in combination with surface-based alignment of the cerebral cortex. The foot, hand, and tongue representations were localized in subjects performing movements. fcMRI maps derived from seed regions placed in different parts of the motor body representation yielded the expected inverted map of somatomotor topography in the anterior lobe and the upright map in the posterior lobe. Next, we mapped the complete topography of the cerebellum by estimating the principal cerebral target for each point in the cerebellum in a discovery sample of 500 subjects and replicated the topography in 500 independent subjects. The majority of the human cerebellum maps to association areas. Quantitative analysis of 17 distinct cerebral networks revealed that the extent of the cerebellum dedicated to each network is proportional to the network's extent in the cerebrum with a few exceptions, including primary visual cortex, which is not represented in the cerebellum. Like somatomotor representations, cerebellar regions linked to association cortex have separate anterior and posterior representations that are oriented as mirror images of one another. The orderly topography of the representations suggests that the cerebellum possesses at least two large, homotopic maps of the full cerebrum and possibly a smaller third map. PMID:21795627

  7. Alternative kynurenic acid synthesis routes studied in the rat cerebellum

    Tonali eBlanco Ayala

    2015-05-01

    Full Text Available Kynurenic acid (KYNA, an astrocyte-derived, endogenous antagonist of α7 nicotinic acetylcholine and excitatory amino acid receptors, regulates glutamatergic, GABAergic, cholinergic and dopaminergic neurotransmission in several regions of the rodent brain. Synthesis of KYNA in the brain and elsewhere is generally attributed to the enzymatic conversion of L-kynurenine (L-KYN by kynurenine aminotransferases (KATs. However, alternative routes, including KYNA formation from D-kynurenine (D-KYN by D-amino acid oxidase (DAAO and the direct transformation of kynurenine to KYNA by reactive oxygen species (ROS, have been demonstrated in the rat brain. Using the rat cerebellum, a region of low KAT activity and high DAAO activity, the present experiments were designed to examine KYNA production from L-KYN or D-KYN by KAT and DAAO, respectively, and to investigate the effect of ROS on KYNA synthesis. In chemical combinatorial systems, both L-KYN and D-KYN interacted directly with peroxynitrite (ONOO- and hydroxyl radicals (OH•, resulting in the formation of KYNA. In tissue homogenates, the non-specific KAT inhibitor aminooxyacetic acid (AOAA; 1 mM reduced KYNA production from L-KYN and D-KYN by 85.1 ± 1.7% and 27.1 ± 4.5%, respectively. Addition of DAAO inhibitors (benzoic acid, kojic acid or 3-methylpyrazole-5-carboxylic acid; 5 µM each attenuated KYNA formation from L-KYN and D-KYN by ~35% and ~66%, respectively. ONOO- (25 µM potentiated KYNA production from both L-KYN and D-KYN, and these effects were reduced by DAAO inhibition. AOAA attenuated KYNA production from L-KYN + ONOO- but not from D-KYN + ONOO-. In vivo, extracellular KYNA levels increased rapidly after perfusion of ONOO- and, more prominently, after subsequent perfusion with L-KYN or D-KYN (100 µM. Taken together, these results suggest that different mechanisms are involved in KYNA production in the rat cerebellum, and that, specifically, DAAO and ROS can function as alternative routes

  8. Microstructural and magnetic properties of L10 FePt-C (0 0 1) textured nanocomposite films grown on different intermediate layers

    Chen, J S; Chow, G M; Lim, B C; Hu, J F; Ding, Y F; Ju, G

    2008-01-01

    The FePt : C films with different volume fractions of carbon and different thicknesses were epitaxially grown on a CrRu(2 0 0) underlayer with Pt and MgO intermediate layers. The magnetic properties and microstructure of these FePt : C films were investigated. The FePt : C films grown on the Pt intermediate layer consisted of a continuous layer of FePt, with overlying granular FePt grains, while the FePt : C films grown on the MgO intermediate layer consisted of granular FePt : C layers with overlying granular grains. The formation of the overlying granular FePt grains was attributed to carbon diffusion to the surface which resulted in the second nucleation of FePt. The different interface energies and surface energies of FePt on Pt and MgO intermediate layers caused the formation of an initial continuous FePt layer on the Pt intermediate layer and initial granular FePt layers on the MgO intermediate layer. The coupling between the continuous FePt layer or the granular FePt layer and the overlying granular FePt grains resulted in simultaneous magnetization reversal and thus strong exchange coupling in FePt : C films.

  9. The control of a manipulator by a computer model of the cerebellum.

    Albus, J. S.

    1973-01-01

    Extension of previous work by Albus (1971, 1972) on the theory of cerebellar function to an application of a computer model of the cerebellum to manipulator control. Following a discussion of the cerebellar function and of a perceptron analogy of the cerebellum, particularly in regard to learning, an electromechanical model of the cerebellum is considered in the form of an IBM 1800 computer connected to a Rancho Los Amigos arm with seven degrees of freedom. It is shown that the computer memory makes it possible to train the arm on some representative sample of the universe of possible states and to achieve satisfactory performance.

  10. File list: His.Neu.20.AllAg.Cerebellum [Chip-atlas[Archive

    Full Text Available His.Neu.20.AllAg.Cerebellum mm9 Histone Neural Cerebellum SRX545939,SRX026427,SRX062951,SRX085450,SRX026429,SRX545929,SRX026428,SRX026430,SRX545934,SRX545933,SRX545924,SRX545923,SRX545926,SRX545940,SRX545936,SRX545935,SRX545938,SRX545937,SRX545928,SRX112921,SRX185818,SRX026433,SRX545930,SRX545925,SRX545927,SRX022870,SRX022871,SRX998311,SRX026434,SRX026432,SRX026431,SRX185811,SRX085441,SRX062950,SRX022869,SRX022868 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.20.AllAg.Cerebellum.bed ...

  11. The critical role of Golgi cells in regulating spatio-temporal integration and plasticity at the cerebellum input stage

    2008-07-01

    Full Text Available After the discovery at the end of the 19th century (Golgi, 1883, the Golgi cell was precisely described by S.R. y Cajal (see Cajal, 1987, 1995 and functionally identified as an inhibitory interneuron 50 years later by J.C. Eccles and colleagues (Eccles e al., 1967. Then, its role has been casted by Marr (1969 within the Motor Learning Theory as a codon size regulator of granule cell activity. It was immediately clear that Golgi cells had to play a critical role, since they are the main inhibitory interneuron of the granular layer and control activity of as many as 100 millions granule cells. In vitro, Golgi cells show pacemaking, resonance, phase-reset and rebound-excitation in the theta-frequency band. These properties are likely to impact on their activity in vivo, which shows irregular spontaneous beating modulated by sensory inputs and burst responses to punctuate stimulation followed by a silent pause. Moreover, investigations have given insight into Golgi cells connectivity within the cerebellar network and on their impact on the spatio-temporal organization of activity. It turns out that Golgi cells can control both the temporal dynamics and the spatial distribution of information transmitted through the cerebellar network. Moreover, Golgi cells regulate the induction of long-term synaptic plasticity at the mossy fiber - granule cell synapse. Thus, the concept is emerging that Golgi cells are of critical importance for regulating granular layer network activity bearing important consequences for cerebellar computation as a whole.

  12. The Effect of Salvia Rhytidea Extract on the Number of Cells of Different Layers of Cerebellar Cortex Following Ischemia Reperfusion in Rats

    M Farahmand

    2016-09-01

    Full Text Available Background & aim: Salvia has anti-oxidant oxygen free radicals which are generated during the interruption and reestablishment of ischemia reperfusion.  The aim of study was to investigate the effect of Salvia Rhytidea extract on the number of cells of different layers of cerebellar cortex following ischemia reperfusion in rats. Methods: In the present experimental study, 35 adult male rats were randomly divided into 7 groups of 5: Group 1 (control-: Sampling without ischemia. Group 2 (control +: Cerebellar ischemia with administration of normal saline. Group 3(sham: Manipulation without ischemia with normal saline administration. Group 4   received (3.2 mg/kg aqueous and alcoholic Salvia extract 2 hours after ischemia. Group 5 received 50 mg/kg silymarin drug, 2 hours after ischemia. Group 6 received 3.2 mg/kg aqueous and alcoholic Salvia extract 72, 48, 24 and 0 h before ischemia and group 7 received silymarin drug (50 mg/kg, 0, 24, 48, and 72, hrs. before ischemia. 24 hrs. following reperfusion, the rats were euthanized and samples of the cerebellum were obtained. By using routine histological technique, the sections were stained by H&E. The measurement of cell count in cerebellar cortex were accomplished. Data were evaluated with One-Way ANOVA and Tukey diagnostic tests. Results: A significant decrease was observed in the number of neural cells in granular layer in the non-treated ischemia group and in the groups which received Salvia extract and silymarin, two hours after the ischemia (p< 0.05. No significant decrease was observed in the number of cells of this layer in the groups which received salvia extract before ischemia. But regarding the cell number of molecular and purkinje layers in above groups, no significant difference was observed compared to the control group (P˃0.05. However, no significant differences was seen in the number of cells layers compared to the control group (P˃0.05. Conclusion: Finally, administration of

  13. Cerebellum engages in automation of verb-generation skill.

    Yang, Zhi; Wu, Paula; Weng, Xuchu; Bandettini, Peter A

    2014-03-01

    Numerous studies have shown cerebellar involvement in item-specific association, a form of explicit learning. However, very few have demonstrated cerebellar participation in automation of non-motor cognitive tasks. Applying fMRI to a repeated verb-generation task, we sought to distinguish cerebellar involvement in learning of item-specific noun-verb association and automation of verb generation skill. The same set of nouns was repeated in six verb-generation blocks so that subjects practiced generating verbs for the nouns. The practice was followed by a novel block with a different set of nouns. The cerebellar vermis (IV/V) and the right cerebellar lobule VI showed decreased activation following practice; activation in the right cerebellar Crus I was significantly lower in the novel challenge than in the initial verb-generation task. Furthermore, activation in this region during well-practiced blocks strongly correlated with improvement of behavioral performance in both the well-practiced and the novel blocks, suggesting its role in the learning of general mental skills not specific to the practiced noun-verb pairs. Therefore, the cerebellum processes both explicit verbal associative learning and automation of cognitive tasks. Different cerebellar regions predominate in this processing: lobule VI during the acquisition of item-specific association, and Crus I during automation of verb-generation skills through practice.

  14. Consensus Paper: Pathological Role of the Cerebellum in Autism

    Fatemi, S. Hossein; Aldinger, Kimberly A.; Ashwood, Paul; Bauman, Margaret L.; Blaha, Charles D.; Blatt, Gene J.; Chauhan, Abha; Chauhan, Ved; Dager, Stephen R.; Dickson, Price E.; Estes, Annette M.; Goldowitz, Dan; Heck, Detlef H.; Kemper, Thomas L.; King, Bryan H.; Martin, Loren A.; Millen, Kathleen J.; Mittleman, Guy; Mosconi, Matthew W.; Persico, Antonio M.; Sweeney, John A.; Webb, Sara J.; Welsh, John P.

    2013-01-01

    There has been significant advancement in various aspects of scientific knowledge concerning the role of cerebellum in the etiopathogenesis of autism. In the current consensus paper, we will observe the diversity of opinions regarding the involvement of this important site in the pathology of autism. Recent emergent findings in literature related to cerebellar involvement in autism are discussed, including: cerebellar pathology, cerebellar imaging and symptom expression in autism, cerebellar genetics, cerebellar immune function, oxidative stress and mitochondrial dysfunction, GABAergic and glutamatergic systems, cholinergic, dopaminergic, serotonergic, and oxytocin related changes in autism, motor control and cognitive deficits, cerebellar coordination of movements and cognition, gene-environment interactions, therapeutics in autism and relevant animal models of autism. Points of consensus include presence of abnormal cerebellar anatomy, abnormal neurotransmitter systems, oxidative stress, cerebellar motor and cognitive deficits, and neuroinflammation in subjects with autism. Undefined areas or areas requiring further investigation include lack of treatment options for core symptoms of autism, vermal hypoplasia and other vermal abnormalities as a consistent feature of autism, mechanisms underlying cerebellar contributions to cognition, and unknown mechanisms underlying neuroinflammation. PMID:22370873

  15. [Pulmonary nocardiasis with abscesses spreading to cerebrum, cerebellum and orbits].

    Borchers, M; von der Mülbe, B; Teikemeier, F; Theegarten, D

    2006-05-12

    A 71-year-old woman presented with suspected tuberculosis. She reported having productive coughs, unwanted weight loss and subfebrile temperature in the preceding 3 months. She was known to have chronic obstructive pulmonary disease treated with corticoids given systemically and by inhalation. She was a heavy smoker. Computed tomography revealed a left apical lung abscess. In the further course of the disease magnetic resonance imaging of the head demonstrated multiple abscesses in both cerebral hemispheres and an abscess, 3.4 cm in diameter, in the right side of the cerebellum, as well as a intra-orbital tumor on the right. Needle aspirate of the eyeball grew Nocardia farcinica. Over 3 weeks antimicrobial treatment was given with imipenem and amikacin, followed by oral cotrimoxazole for 12 months. The abscesses completely regressed and after 12 months no recurrence was demonstrated either radiologically or clinically. Although nocardiasis is rare in Germany it must be included in the differential diagnosis of pneumonia with abscesses. This is especially so if acid-fast bacilli are found. As the resistance pattern of N. farcinica to antibiotics varies, early treatment is essential with antibiotics to which it is sensitive.

  16. Switching On Depression and Potentiation in the Cerebellum

    Andrew R. Gallimore

    2018-01-01

    Full Text Available Long-term depression (LTD and long-term potentiation (LTP in the cerebellum are important for motor learning. However, the signaling mechanisms controlling whether LTD or LTP is induced in response to synaptic stimulation remain obscure. Using a unified model of LTD and LTP at the cerebellar parallel fiber-Purkinje cell (PF-PC synapse, we delineate the coordinated pre- and postsynaptic signaling that determines the direction of plasticity. We show that LTP is the default response to PF stimulation above a well-defined frequency threshold. However, if the calcium signal surpasses the threshold for CaMKII activation, then an ultrasensitive “on switch” activates an extracellular signal-regulated kinase (ERK-based positive feedback loop that triggers LTD instead. This postsynaptic feedback loop is sustained by another, trans-synaptic, feedback loop that maintains nitric oxide production throughout LTD induction. When full depression is achieved, an automatic “off switch” inactivates the feedback loops, returning the network to its basal state and demarcating the end of the early phase of LTD.

  17. Consensus paper: pathological role of the cerebellum in autism.

    Fatemi, S Hossein; Aldinger, Kimberly A; Ashwood, Paul; Bauman, Margaret L; Blaha, Charles D; Blatt, Gene J; Chauhan, Abha; Chauhan, Ved; Dager, Stephen R; Dickson, Price E; Estes, Annette M; Goldowitz, Dan; Heck, Detlef H; Kemper, Thomas L; King, Bryan H; Martin, Loren A; Millen, Kathleen J; Mittleman, Guy; Mosconi, Matthew W; Persico, Antonio M; Sweeney, John A; Webb, Sara J; Welsh, John P

    2012-09-01

    There has been significant advancement in various aspects of scientific knowledge concerning the role of cerebellum in the etiopathogenesis of autism. In the current consensus paper, we will observe the diversity of opinions regarding the involvement of this important site in the pathology of autism. Recent emergent findings in literature related to cerebellar involvement in autism are discussed, including: cerebellar pathology, cerebellar imaging and symptom expression in autism, cerebellar genetics, cerebellar immune function, oxidative stress and mitochondrial dysfunction, GABAergic and glutamatergic systems, cholinergic, dopaminergic, serotonergic, and oxytocin-related changes in autism, motor control and cognitive deficits, cerebellar coordination of movements and cognition, gene-environment interactions, therapeutics in autism, and relevant animal models of autism. Points of consensus include presence of abnormal cerebellar anatomy, abnormal neurotransmitter systems, oxidative stress, cerebellar motor and cognitive deficits, and neuroinflammation in subjects with autism. Undefined areas or areas requiring further investigation include lack of treatment options for core symptoms of autism, vermal hypoplasia, and other vermal abnormalities as a consistent feature of autism, mechanisms underlying cerebellar contributions to cognition, and unknown mechanisms underlying neuroinflammation.

  18. Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease)

    Uki, Jiro; Kanda, Shinji; Asakura, Ken; Takeda, Fumikazu

    1985-01-01

    A case of dysplastic gangliocytoma of the cerebellum, or Lhermitte-Duclos disease, is reported along with its CT findings, and the cases so far reported in the literature are reviewed. This is the 50th case report since the first description in 1920. This 61-year-old female had suffered from right hemifacial spasms for more than 20 years and from bilateral tinnitus with auditory disturbances for two years. Four years before admission, she underwent gastric resection and cancer chemotherapy for gastric cancer. Plain craniograms showed a thinned and ballooned occipital squama on the right side. Vertebral angiograms revealed a large tumor stain, with early venous filling, in the right posterior fossa. A CT scan showed a large, low-density mass, with small calcified areas in it, in the right posterior fossa. A postcontrast CT scan revealed no contrast enhancement, except for dilated vascular enhancement, within the tumor. No hydrocephalus was observed. Metrizamide CT cisternography revealed a huge intraaxial mass compressing the brain stem. (J.P.N.)

  19. Ethanol Neurotoxicity in the Developing Cerebellum: Underlying Mechanisms and Implications

    Ambrish Kumar

    2013-06-01

    Full Text Available Ethanol is the main constituent of alcoholic beverages that exerts toxicity to neuronal development. Ethanol affects synaptogenesis and prevents proper brain development. In humans, synaptogenesis takes place during the third trimester of pregnancy, and in rodents this period corresponds to the initial few weeks of postnatal development. In this period neuronal maturation and differentiation begin and neuronal cells start migrating to their ultimate destinations. Although the neuronal development of all areas of the brain is affected, the cerebellum and cerebellar neurons are more susceptible to the damaging effects of ethanol. Ethanol’s harmful effects include neuronal cell death, impaired differentiation, reduction of neuronal numbers, and weakening of neuronal plasticity. Neuronal development requires many hormones and growth factors such as retinoic acid, nerve growth factors, and cytokines. These factors regulate development and differentiation of neurons by acting through various receptors and their signaling pathways. Ethanol exposure during development impairs neuronal signaling mechanisms mediated by the N-methyl-d-aspartate (NMDA receptors, the retinoic acid receptors, and by growth factors such as brain-derived neurotrophic factor (BDNF, insulin-like growth factor 1 (IGF-I, and basic fibroblast growth factor (bFGF. In combination, these ethanol effects disrupt cellular homeostasis, reduce the survival and migration of neurons, and lead to various developmental defects in the brain. Here we review the signaling mechanisms that are required for proper neuronal development, and how these processes are impaired by ethanol resulting in harmful consequences to brain development.

  20. Rheology of confined granular flows: scale invariance, glass transition, and friction weakening.

    Richard, P; Valance, A; Métayer, J-F; Sanchez, P; Crassous, J; Louge, M; Delannay, R

    2008-12-12

    We study fully developed, steady granular flows confined between parallel flat frictional sidewalls using numerical simulations and experiments. Above a critical rate, sidewall friction stabilizes the underlying heap at an inclination larger than the angle of repose. The shear rate is constant and independent of inclination over much of the flowing layer. In the direction normal to the free surface, the solid volume fraction increases on a scale equal to half the flowing layer depth. Beneath a critical depth at which internal friction is invariant, grains exhibit creeping and intermittent cage motion similar to that in glasses, causing gradual weakening of friction at the walls.

  1. Quantification of 5-hydroxytryptamine[sub 1A] receptors in the cerebellum of normal and x-irradiated rats during postnatal development

    Matthiessen, L; Daval, G; Bailly, Y [Pierre et Marie Curie Univ., Paris (France). Centre National de la Recherche Scientifique, UA; Gozlan, H; Hamon, M; Verge, D [INSERM, Paris (France). Lab. de Neurobiologie Cellulaire et Fonctionnelle

    1992-11-01

    5-Hydroxytryptamine[sub 1A] receptors were studied in rats during the first postnatal month in the normal cerebellum and in the granule cell-deprived cerebellum produced by X-irradiation at postnatal day 5. Quantitative autoradiographic studies on sagittal sections of cerebellar vermis, using [[sup 125]1]BH-8-MeO-N-PAT as radioligand or specific anti-receptor antibodies, revealed that 5-hydroxytryptamine[sub 1A] receptors existed in the molecular/Purkinje cell layer but at variable density from one lobule to another. Thus, in both normal and X-irradiated rats, the posterior lobules were more heavily labelled than the anterior ones, and the density of 5-hydroxytryptamine[sub 1A] sites decreased progressively in all the cerebellar folia down to hardly detectable levels at postnatal day 21. However, the intensity of labelling remained higher at postnatal day 8 and postnatal day 12 in X-irradiated rats than in age-paired controls. Measurements of [[sup 3]H]8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] specific binding to membranes from whole cerebellum confirmed that the density of 5-hydroxytryptamine[sub 1A] sites per mg membrane protein (B[sub max]) was higher in X-irradiated animals than in age-paired controls. However, on a ''per cerebellum'' basis, no significant difference could be detected between the total number of 5-hydroxytryptamine[sub 1A] sites, which progressively increased in both control and X-irradiated animals during the first postnatal month. These results therefore show that 5-hydroxytryptamine[sub 1A] receptors are not located on developing granule cells. (author).

  2. TMS Over the Cerebellum Interferes with Short-term Memory of Visual Sequences.

    Ferrari, C; Cattaneo, Z; Oldrati, V; Casiraghi, L; Castelli, F; D'Angelo, E; Vecchi, T

    2018-04-30

    Growing evidence suggests that the cerebellum is not only involved in motor functions, but it significantly contributes to sensory and cognitive processing as well. In particular, it has been hypothesized that the cerebellum identifies recurrent serial events and recognizes their violations. Here we used transcranial magnetic stimulation (TMS) to shed light on the role of the cerebellum in short-term memory of visual sequences. In two experiments, we found that TMS over the right cerebellar hemisphere impaired participants' ability to recognize the correct order of appearance of geometrical stimuli varying in shape and/or size. In turn, cerebellar TMS did not affect recognition of highly familiar short sequences of letters or numbers. Overall, our data suggest that the cerebellum is involved in memorizing the order in which (concatenated) stimuli appear, this process being important for sequence learning.

  3. A functional MRI study of somatotopic representation of somatosensory stimulation in the cerebellum

    Takanashi, M.; Abe, K.; Yanagihara, T.; Sakoda, S. [Dept. of Neurology D4, Osaka Univ. Graduate School of Medicine, Suita City, Osaka (Japan); Tanaka, H.; Hirabuki, N.; Nakamura, H.; Fujita, N. [Dept. of Radiology, Osaka Univ. Graduate School of Medicine, Suita City, Osaka (Japan)

    2003-03-01

    Somatotopic representation in the cerebral cortex of somatosensory stimulation has been widely reported, but that in the cerebellum has not. We investigated the latter in the human cerebellum by functional MRI (fMRI). Using a 1.5 tesla imager, we obtained multislice blood oxygen level-dependent fMRI with single-shot gradient-echo echoplanar imaging in seven right-handed volunteers during electrical stimulation of the left index finger and big toe. In the anterior and posterior cerebellum, activated pixels for the index finger were separate from those for the toe. This suggests that somatosensory stimulation of different parts of the body may involve distinct areas of in the cerebellum as well as the cerebral cortex. (orig.)

  4. A functional MRI study of somatotopic representation of somatosensory stimulation in the cerebellum

    Takanashi, M.; Abe, K.; Yanagihara, T.; Sakoda, S.; Tanaka, H.; Hirabuki, N.; Nakamura, H.; Fujita, N.

    2003-01-01

    Somatotopic representation in the cerebral cortex of somatosensory stimulation has been widely reported, but that in the cerebellum has not. We investigated the latter in the human cerebellum by functional MRI (fMRI). Using a 1.5 tesla imager, we obtained multislice blood oxygen level-dependent fMRI with single-shot gradient-echo echoplanar imaging in seven right-handed volunteers during electrical stimulation of the left index finger and big toe. In the anterior and posterior cerebellum, activated pixels for the index finger were separate from those for the toe. This suggests that somatosensory stimulation of different parts of the body may involve distinct areas of in the cerebellum as well as the cerebral cortex. (orig.)

  5. Selective survival of β1-adenergic receptors in rat cerebellum following neonatal X-irradiation

    Minneman, K.P.; Pittman, R.N.; Wolfe, B.B.; Molinoff, P.B.

    1981-01-01

    To investigate the cellular localization of β 1 - and β 2 -adrenergic receptors, the effects of intermittent neonatal X-irradiation focused on the cerebellum were determined on the densities of the two subtypes of β-adrenergic receptor. This treatment destroys the late-maturing cerebellar interneurons including the granule, basket and stellate cells. The total number of β 2 -adrenergic receptors per cerebellum was reduced by 81-83% in 6- and 12-week-old X-irradiated rats. However, the number of β 1 -adrenergic receptors per cerebellum in 6- and 12-week-old X-irradiated rats was not significantly different from that in control animals. The results suggest that β 2 receptors in the rat cerebellum are primarily associated with the small interneurons destroyed by neonatal X-irradiation. The β 1 receptors may be located on a cell population which is unaffected by this treatment, possibly on cerebellar Purkinje cells. (Auth.)

  6. The cerebellum: its role in language and related cognitive and affective functions.

    De Smet, Hyo Jung; Paquier, Philippe; Verhoeven, Jo; Mariën, Peter

    2013-12-01

    The traditional view on the cerebellum as the sole coordinator of motor function has been substantially redefined during the past decades. Neuroanatomical, neuroimaging and clinical studies have extended the role of the cerebellum to the modulation of cognitive and affective processing. Neuroanatomical studies have demonstrated cerebellar connectivity with the supratentorial association areas involved in higher cognitive and affective functioning, while functional neuroimaging and clinical studies have provided evidence of cerebellar involvement in a variety of cognitive and affective tasks. This paper reviews the recently acknowledged role of the cerebellum in linguistic and related cognitive and behavioral-affective functions. In addition, typical cerebellar syndromes such as the cerebellar cognitive affective syndrome (CCAS) and the posterior fossa syndrome (PFS) will be briefly discussed and the current hypotheses dealing with the presumed neurobiological mechanisms underlying the linguistic, cognitive and affective modulatory role of the cerebellum will be reviewed. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Psychophysiological interaction between superior temporal gyrus (STG) and cerebellum: An fMRI study

    Yusoff, A. N.; Teng, X. L.; Ng, S. B.; Hamid, A. I. A.; Mukari, S. Z. M.

    2016-03-01

    This study aimed to model the psychophysiological interaction (PPI) between the bilateral STG and cerebellum (lobule VI and lobule VII) during an arithmetic addition task. Eighteen young adults participated in this study. They were instructed to solve single-digit addition tasks in quiet and noisy backgrounds during an fMRI scan. Results showed that in both hemispheres, the response in the cerebellum was found to be linearly influenced by the activity in STG (vice-versa) for both in-quiet and in-noise conditions. However, the influence of the cerebellum on STG seemed to be modulated by noise. A two-way PPI model between STG and cerebellum is suggested. The connectivity between the two regions during a simple addition task in a noisy condition is modulated by the participants’ higher attention to perceive.

  8. Neuro-protective effects of Crocin on brain and cerebellum tissues in ...

    ... make the neurons and astrocytes more sensitive against oxidative damage. ... Malondialdehyde (MDA), glutathione (GSH), blood glucose, HbA1c levels and ... appearence of the cerebrum and cerebellum were normal in the control group.

  9. NMR studies of granular media and two-phase flow in porous media

    Yang, Xiaoyu

    This dissertation describes two experimental studies of a vibrofluidized granular medium and a preliminary study of two-phase fluid flow in a porous medium using Nuclear Magnetic Resonance (NMR). The first study of granular medium is to test a scaling law of the rise in center of mass in a three-dimensional vibrofluidized granular system. Our granular system consisted of mustard seeds vibrated vertically at 40 Hz from 0g to 14g. We used Magnetic Resonance Imaging (MRI) to measure density profile in vibrated direction. We observed that the rise in center of mass scaled as nu 0alpha/Nlbeta with alpha = 1.0 +/- 0.2 and beta = 0.5 +/- 0.1, where nu 0 is the vibration velocity and Nl is the number of layers of grains in the container. A simple theory was proposed to explain the scaling exponents. In the second study we measured both density and velocity information in the same setup of the first study. Pulsed Field Gradient (PFG)-NMR combined with MRI was used to do this measurement. The granular system was fully fluidized at 14.85g 50 Hz with Nl ≤ 4. The velocity distributions at horizontal and vertical direction at different height were measured. The distributions were nearly-Gaussian far from sample bottom and non-Gaussian near sample bottom. Granular temperature profiles were calculated from the velocity distributions. The density and temperature profile were fit to a hydrodynamic theory. The theory agreed with experiments very well. A temperature inversion near top was also observed and explained by additional transport coefficient from granular hydrodynamics. The third study was the preliminary density measurement of invading phase profile in a two-phase flow in porous media. The purpose of this study was to test an invasion percolation with gradient (IPG) theory in two-phase flow of porous media. Two phases are dodecane and water doped with CuSO4. The porous medium was packed glass beads. The front tail width sigma and front width of invading phase were

  10. Constitutive law of dense granular matter

    Hatano, Takahiro

    2010-01-01

    The frictional properties of dense granular matter under steady shear flow are investigated using numerical simulation. Shear flow tends to localize near the driving boundary unless the coefficient of restitution is close to zero and the driving velocity is small. The bulk friction coefficient is independent of shear rate in dense and slow flow, whereas it is an increasing function of shear rate in rapid flow. The coefficient of restitution affects the friction coefficient only in such rapid flow. Contrastingly, in dense and slow regime, the friction coefficient is independent of the coefficient of restitution and mainly determined by the elementary friction coefficient and the rotation of grains. It is found that the mismatch between the vorticity of flow and the angular frequency of grains plays a key role to the frictional properties of sheared granular matter.

  11. An automata model of granular materials

    Gutt, G.M.; Haff, P.K.

    1990-01-01

    In this paper a new modeling technique (the Lattice Grain Model) is presented for the simulation of two-dimensional granular systems involving large numbers of grains. These granular systems may include both high shear rate regions as well as static plugs of grains and cannot easily be handled within the framework of existing continuum theories such as soil mechanics. The Lattice Grain Model (LGrM) is similar to the Lattice Gas Model (LBM). This allows large simulations to be programmed onto a hypercube concurrent processor in a straightforward manner. However, it differs from LBM in that it includes the inelastic collisions and volume-filling properties of macroscopic grains. Examples to be presented will include Couette flow, flow through an hourglass, and gravity-driven flows around obstacles

  12. Submammary Granular Parakeratosis Treated With Mastopexy.

    Nelson, Garrett; Lien, Mary H; Messina, Jane L; Ranjit, Sonali; Fenske, Neil Alan

    2017-08-01

    Granular parakeratosis, originally named axillary granular parakeratosis, is an uncommon disease with an unclear etiology. It is thought to result from defective processing of profillagrin to fillagrin, causing retention of keratohyaline granules in the epidermis. A myriad of causative factors has been proposed, including friction, moisture, heat, and contact irritants such as deodorants. We present a case in the inframammary area that resolved with mastopexy, further supporting the role of friction, moisture, and heat. Furthermore, we present electron microscopic evidence demonstrating non-degraded keratohyaline granules upon epidermal maturation. This entity, we believe, is reactive and represents a protective response of the body to moisture and heat. J Drugs Dermatol. 2017;16(8):810-812..

  13. Granular flow down a flexible inclined plane

    Sonar Prasad

    2017-01-01

    Full Text Available Discrete and continuous systems are commonly studied individually, but seldom together. Indeed, granular flows are typically studied through flows over a rigid base. Here, we investigate the behaviour of granular flows over an inclined, flexible base. The flexible base is modeled as a rigid platform mounted on springs and has one degree of freedom. The base vibrations are introduced by the flow. We simulate such flows through a discrete element method and compare with experiments. We find that a flexible base increased the upper limit of the inclination up to which a steady flow is possible by at least 3 degrees. This stabilized zone may have important implications in applications such as conveyor belts and chutes.

  14. Memory effect in uniformly heated granular gases

    Trizac, E.; Prados, A.

    2014-07-01

    We evidence a Kovacs-like memory effect in a uniformly driven granular gas. A system of inelastic hard particles, in the low density limit, can reach a nonequilibrium steady state when properly forced. By following a certain protocol for the drive time dependence, we prepare the gas in a state where the granular temperature coincides with its long time value. The temperature subsequently does not remain constant but exhibits a nonmonotonic evolution with either a maximum or a minimum, depending on the dissipation and on the protocol. We present a theoretical analysis of this memory effect at Boltzmann-Fokker-Planck equation level and show that when dissipation exceeds a threshold, the response can be called anomalous. We find excellent agreement between the analytical predictions and direct Monte Carlo simulations.

  15. Tumor of granular cells of esophagus

    Gonzalez Fabian, Licet; Diaz Anaya, Amnia; Perez de la Torre, Georgina

    2010-01-01

    Granular cells tumors are rare and asymptomatic lesions and by general, it is an incidental finding en high or low endoscopy. They were described for the first time by Abrikossoff in 1926. The more frequent locations are the buccal mucosa, dermis and subcutaneous cellular tissue, most of these tumors has a benign origin. This is the case of a woman aged 44 with a pyrosis history from a year ago; by high endoscopy it is noted a 8 mm lesion distal to esophagus and confirmed by histological study of granular cells tumor. Elective treatment of this lesion is the endoscopic polypectomy. Despite that the malign potential is low; we suggested a close clinical and endoscopic follow-up.

  16. Traffic and Granular Flow ’07

    Chevoir, François; Gondret, Philippe; Lassarre, Sylvain; Lebacque, Jean-Patrick; Schreckenberg, Michael

    2009-01-01

    This book covers several research fields, all of which deal with transport. Three main topics are treated: road traffic, granular matter, and biological transport. Different points of view, i.e. modelling, simulations, experiments, and phenomenological observations, are considered. Sub-topics include: highway or urban vehicular traffic (dynamics of traffic, macro/micro modelling, measurements, data analysis, security issues, psychological issues), pedestrian traffic, animal traffic (e.g. social insects), collective motion in biological systems (molecular motors...), granular flow (dense flows, intermittent flows, solid/liquid transition, jamming, force networks, fluid and solid friction), networks (biological networks, urban traffic, the internet, vulnerability of networks, optimal transport networks) and cellular automata applied to the various aforementioned fields.

  17. Evaluating Energy Flux in Vibrofluidized Granular Bed

    N. A. Sheikh

    2013-01-01

    Full Text Available Granular flows require sustained input of energy for fluidization. A level of fluidization depends on the amount of heat flux provided to the flow. In general, the dissipation of the grains upon interaction balances the heat inputs and the resultant flow patterns can be described using hydrodynamic models. However, with the increase in packing fraction, the heat fluxes prediction of the cell increases. Here, a comparison is made for the proposed theoretical models against the MD simulations data. It is observed that the variation of packing fraction in the granular cell influences the heat flux at the base. For the elastic grain-base interaction, the predictions vary appreciably compared to MD simulations, suggesting the need to accurately model the velocity distribution of grains for averaging.

  18. Granularity controlled irradiation response of cuprate superconductors

    Mishra, N.C.; Behera, D.; Mohanty, T.; Mohanta, D.; Kanjilal, D.; Mehta, G.K.; Pinto, R.

    1999-01-01

    Confining to an energy range where ions can neither create defects through elastic energy loss nor they can create defects through latent track formation, we study the effect of 140 MeV Si-ion irradiation in YBa 2 Cu 3 O 7-x (YBCO). We show that the evolution of superconducting and normal state properties in such situation is largely governed by the initial defects structure, particularly the grain boundary characteristics of the YBCO system. Both intra- and inter-granular defect structure in films of two batches were made widely different by having Ag as composite and substituent in one and by aging the other prior to irradiation. Evolution of the resistivity vs temperature characteristics in these films with ion fluence reveals the importance of Ag in bringing about both inter- and intra-granular modifications and making the films insensitive to ion irradiation

  19. Mathematics and Mechanics of Granular Materials

    Hill, James M

    2005-01-01

    Granular or particulate materials arise in almost every aspect of our lives, including many familiar materials such as tea, coffee, sugar, sand, cement and powders. At some stage almost every industrial process involves a particulate material, and it is usually the cause of the disruption to the smooth running of the process. In the natural environment, understanding the behaviour of particulate materials is vital in many geophysical processes such as earthquakes, landslides and avalanches. This book is a collection of current research from some of the major contributors in the topic of modelling the behaviour of granular materials. Papers from every area of current activity are included, such as theoretical, numerical, engineering and computational approaches. This book illustrates the numerous diverse approaches to one of the outstanding problems of modern continuum mechanics.

  20. Slow creep in soft granular packings.

    Srivastava, Ishan; Fisher, Timothy S

    2017-05-14

    Transient creep mechanisms in soft granular packings are studied numerically using a constant pressure and constant stress simulation method. Rapid compression followed by slow dilation is predicted on the basis of a logarithmic creep phenomenon. Characteristic scales of creep strain and time exhibit a power-law dependence on jamming pressure, and they diverge at the jamming point. Microscopic analysis indicates the existence of a correlation between rheology and nonaffine fluctuations. Localized regions of large strain appear during creep and grow in magnitude and size at short times. At long times, the spatial structure of highly correlated local deformation becomes time-invariant. Finally, a microscale connection between local rheology and local fluctuations is demonstrated in the form of a linear scaling between granular fluidity and nonaffine velocity.

  1. Characterization of beta-adrenergic receptors in synaptic membranes from rat cerebral cortex and cerebellum

    Lautens, L.

    1986-01-01

    Beta-adrenergic receptor ligand binding sites have been characterized in synaptic membranes from rat cerebral cortex and cerebellum using radioligand binding techniques. The equilibrium and kinetic properties of binding were assessed. The binding sites were non-interacting and exhibited two states of agonist binding which were sensitive to guanyl nucleotide. Synaptic membranes from cerebral cortex contained an equal number of beta 1 - and beta 2 -receptors; membranes from cerebellum possessed more beta 2 -than beta 1 -receptors. Photoaffinity labeling experiments revealed two different beta-adrenergic receptor polypeptides, R 1 and R 2 (and possibly a third, R 3 ) in synaptic membranes. The ratios of incorporation of photoaffinity label into R 1 : 2 were approximately 1:1 (cerebral cortex) and 5:1 (cerebellum). Photoaffinity labeling of R 1 and R 2 was inhibited equally well by both agonist and antagonist in synaptic membranes from cerebellum; whereas agonist was a less potent inhibitor in membranes from cerebral cortex. Both subtypes of beta-adrenergic receptors exhibited the same apparent molecular weight in synaptic membranes from cerebral cortex. The beta-adrenergic receptors in synaptic membranes from cerebral cortex and cerebellum were glycoproteins which exhibited the same apparent molecular weight after exposure to endoglycosidase F. The partial proteolytic digest maps of photoaffinity labeled beta-adrenergic receptors from rat cerebral cortex, cerebellum, lung and heart were compared

  2. Quantifying Cerebellum Grey Matter and White Matter Perfusion Using Pulsed Arterial Spin Labeling

    Xiufeng Li

    2014-01-01

    Full Text Available To facilitate quantification of cerebellum cerebral blood flow (CBF, studies were performed to systematically optimize arterial spin labeling (ASL parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM and white matter (WM, and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1 mL/100 g/min for GM and 27.6 ± 4.5 mL/100 g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values.

  3. Quantifying cerebellum grey matter and white matter perfusion using pulsed arterial spin labeling.

    Li, Xiufeng; Sarkar, Subhendra N; Purdy, David E; Briggs, Richard W

    2014-01-01

    To facilitate quantification of cerebellum cerebral blood flow (CBF), studies were performed to systematically optimize arterial spin labeling (ASL) parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM) and white matter (WM), and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1 mL/100 g/min for GM and 27.6 ± 4.5 mL/100 g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values.

  4. Quantifying Cerebellum Grey Matter and White Matter Perfusion Using Pulsed Arterial Spin Labeling

    Li, Xiufeng; Sarkar, Subhendra N.; Purdy, David E.; Briggs, Richard W.

    2014-01-01

    To facilitate quantification of cerebellum cerebral blood flow (CBF), studies were performed to systematically optimize arterial spin labeling (ASL) parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM) and white matter (WM), and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1 mL/100 g/min for GM and 27.6 ± 4.5 mL/100 g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values. PMID:24949416

  5. Functional imaging of the cerebellum and basal ganglia during predictive motor timing in early Parkinson's disease.

    Husárová, Ivica; Lungu, Ovidiu V; Mareček, Radek; Mikl, Michal; Gescheidt, Tomáš; Krupa, Petr; Bareš, Martin

    2014-01-01

    The basal ganglia and the cerebellum have both emerged as important structures involved in the processing of temporal information. We examined the roles of the cerebellum and striatum in predictive motor timing during a target interception task in healthy individuals (HC group; n = 21) and in patients with early Parkinson's disease (early stage PD group; n = 20) using functional magnetic resonance imaging. Despite having similar hit ratios, the PD failed more often than the HC to postpone their actions until the right moment and to adapt their behavior from one trial to the next. We found more activation in the right cerebellar lobule VI in HC than in early stage PD during successful trials. Successful trial-by-trial adjustments were associated with higher activity in the right putamen and lobule VI of the cerebellum in HC. We conclude that both the cerebellum and striatum are involved in predictive motor timing tasks. The cerebellar activity is associated exclusively with the postponement of action until the right moment, whereas both the cerebellum and striatum are needed for successful adaptation of motor actions from one trial to the next. We found a general ''hypoactivation'' of basal ganglia and cerebellum in early stage PD relative to HC, indicating that even in early stages of the PD there could be functional perturbations in the motor system beyond striatum. Copyright © 2011 by the American Society of Neuroimaging.

  6. Contributions of the cerebellum to disturbed central processing of visceral stimuli in irritable bowel syndrome.

    Rosenberger, Christina; Thürling, Markus; Forsting, Michael; Elsenbruch, Sigrid; Timmann, Dagmar; Gizewski, Elke R

    2013-04-01

    There is evidence to support that the cerebellum contributes to the neural processing of both emotions and painful stimuli. This could be particularly relevant in conditions associated with chronic abdominal pain, such as the irritable bowel syndrome (IBS), which are often also characterized by affective disturbances. We aimed to test the hypothesis that in IBS, symptoms of anxiety and depression modulate brain activation during visceral stimulation within the cerebellum. We reanalyzed a previous data set from N = 15 female IBS patients and N = 12 healthy women with a specific focus on the cerebellum using advanced normalization methods. Rectal distension-induced brain activation was measured with functional magnetic resonance imaging using non-painful and painful rectal distensions. Symptoms of anxiety and depression, assessed with the Hospital Anxiety and Depression scale, were correlated with cerebellar activation within IBS patients. Within IBS, depression scores were associated with non-painful distension-induced activation in the right cerebellum primarily in Crus II and lobule VIIIb, and additionally in Crus I. Depression scores were also associated with painful distension-induced activation predominantly in vermal lobule V with some extension to the intermediate cerebellum. Anxiety scores correlated significantly with non-painful induced activation in Crus II. Symptoms of anxiety and depression, which are frequently found in chronic pain conditions like IBS, modulate activation during visceral sensory signals not only in cortical and subcortical brain areas but also in the cerebellum.

  7. Moving Forward: Age Effects on the Cerebellum Underlie Cognitive and Motor Declines

    Bernard, Jessica A.; Seidler, Rachael D.

    2014-01-01

    Though the cortical contributions to age-related declines in motor and cognitive performance are well-known, the potential contributions of the cerebellum are less clear. The diverse functions of the cerebellum make it an important structure to investigate in aging. Here, we review the extant literature on this topic. To date, there is evidence to indicate that there are morphological age differences in the cerebellum that are linked to motor and cognitive behavior. Cerebellar morphology is often as good as -- or even better -- at predicting performance than the prefrontal cortex. We also touch on the few studies using functional neuroimaging and connectivity analyses that further implicate the cerebellum in age-related performance declines. Importantly, we provide a conceptual framework for the cerebellum influencing age differences in performance, centered on the notion of degraded internal models. The evidence indicating that cerebellar age differences associate with performance highlights the need for additional work in this domain to further elucidate the role of the cerebellum in age differences in movement control and cognitive function. PMID:24594194

  8. Cerebellar nicotinic cholinergic receptors are intrinsic to the cerebellum: implications for diverse functional roles.

    Turner, Jill R; Ortinski, Pavel I; Sherrard, Rachel M; Kellar, Kenneth J

    2011-12-01

    Although recent studies have delineated the specific nicotinic subtypes present in the mammalian cerebellum, very little is known about their location or function within the cerebellum. This is of increased interest since nicotinic receptors (nAChRs) in the cerebellum have recently been implicated in the pathology of autism spectrum disorders. To begin to better understand the roles of these heteromeric nAChRs in the cerebellar circuitry and their therapeutic potential as targets for drug development, we used various chemical and stereotaxic lesion models in conjunction with slice electrophysiology to examine how specific heteromeric nAChR subtypes may influence the surrounding cerebellar circuitry. Using subunit-specific immunoprecipitation of radiolabeled nAChRs in the cerebella following N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride, p-chloroamphetamine, and pendunculotomy lesions, we show that most, if not all, cerebellar nicotinic receptors are present in cells within the cerebellum itself and not in extracerebellar afferents. Furthermore, we demonstrate that the β4-containing, but not the β2-containing, nAChRs intrinsic to the cerebellum can regulate inhibitory synaptic efficacy at two major classes of cerebellar neurons. These tandem findings suggest that nAChRs may present a potential drug target for disorders involving the cerebellum.

  9. Fuzzy batch controller for granular materials

    Zamyatin Nikolaj; Smirnov Gennadij; Fedorchuk Yuri; Rusina Olga

    2018-01-01

    The paper focuses on batch control of granular materials in production of building materials from fluorine anhydrite. Batching equipment is intended for smooth operation and timely feeding of supply hoppers at a required level. Level sensors and a controller of an asynchronous screw drive motor are used to control filling of the hopper with industrial anhydrite binders. The controller generates a required frequency and ensures required productivity of a feed conveyor. Mamdani-type fuzzy infer...

  10. Arching Structures in Granular Sedimentary Deposits

    Kulaviak, Lukáš; Hladil, Jindřich; Růžička, Marek; Drahoš, Jiří; Saint-Lary, L.

    2013-01-01

    Roč. 246, SEP (2013), s. 269-277 ISSN 0032-5910 R&D Projects: GA ČR GA104/07/1110; GA AV ČR IAAX00130702; GA MŠk(CZ) LG11014 Institutional support: RVO:67985858 ; RVO:67985831 Keywords : wet granulars * deposit * arching structure Subject RIV: CI - Industrial Chemistry, Chemical Engineering; DB - Geology ; Mineralogy (GLU-S) Impact factor: 2.269, year: 2013

  11. Seismic wave propagation in granular media

    Tancredi, Gonzalo; López, Francisco; Gallot, Thomas; Ginares, Alejandro; Ortega, Henry; Sanchís, Johnny; Agriela, Adrián; Weatherley, Dion

    2016-10-01

    Asteroids and small bodies of the Solar System are thought to be agglomerates of irregular boulders, therefore cataloged as granular media. It is a consensus that many asteroids might be considered as rubble or gravel piles.Impacts on their surface could produce seismic waves which propagate in the interior of these bodies, thus causing modifications in the internal distribution of rocks and ejections of particles and dust, resulting in a cometary-type comma.We present experimental and numerical results on the study of propagation of impact-induced seismic waves in granular media, with special focus on behavior changes by increasing compression.For the experiment, we use an acrylic box filled with granular materials such as sand, gravel and glass spheres. Pressure inside the box is controlled by a movable side wall and measured with sensors. Impacts are created on the upper face of the box through a hole, ranging from free-falling spheres to gunshots. We put high-speed cameras outside the box to record the impact as well as piezoelectic sensors and accelerometers placed at several depths in the granular material to detect the seismic wave.Numerical simulations are performed with ESyS-Particle, a software that implements the Discrete Element Method. The experimental setting is reproduced in the numerical simulations using both individual spherical particles and agglomerates of spherical particles shaped as irregular boulders, according to rock models obtained with a 3D scanner. The numerical experiments also reproduces the force loading on one of the wall to vary the pressure inside the box.We are interested in the velocity, attenuation and energy transmission of the waves. These quantities are measured in the experiments and in the simulations. We study the dependance of these three parameters with characteristics like: impact speed, properties of the target material and the pressure in the media.These results are relevant to understand the outcomes of impacts in

  12. Simulation of 2D Granular Hopper Flow

    Li, Zhusong; Shattuck, Mark

    2012-02-01

    Jamming and intermittent granular flow are big problems in industry, and the vertical hopper is a canonical example of these difficulties. We simulate gravity driven flow and jamming of 2D disks in a vertical hopper and compare with identical companion experiments presented in this session. We measure and compare the flow rate and probability for jamming as a function of particle properties and geometry. We evaluate the ability of standard Hertz-Mindlin contact mode to quantitatively predict the experimental flow.

  13. Spatial correlations in compressible granular flows

    Van Noije, T. P. C.; Ernst, M. H.; Brito López, Ricardo

    1998-01-01

    The clustering instability in freely evolving granular fluids manifests itself in the density-density correlation function and structure factor. These functions are calculated from fluctuating hydrodynamics. As time increases, the structure factor of density fluctuations develops a maximum, which shifts to smaller wave numbers (growing correlation length). Furthermore, the inclusion of longitudinal velocity fluctuations changes long-range correlations in the flow field qualitatively and exten...

  14. Deformación permanente de materiales granulares en pavimentos flexibles: estado del conocimiento Permanent strain of granular materials in flexible pavements: state of the art

    Hugo Alexánder Rondón

    2009-01-01

    Full Text Available Diversos estudios han sido desarrollados en el área de los pavimentos para comprender el comportamiento elastoplástico que experimentan materiales granulares bajo carga cíclica. Este es el segundo de dos artículos que presentan el estado del conocimiento de investigaciones desarrolladas en esta área. Basado en una amplia revisión bibliográfica, este artículo da cuenta de la forma como ha sido estudiado el fenómeno de deformación permanente en materiales granulares empleados para conformar capas de base y sub-base de estructuras de pavimentos flexibles. Además, se exponen y se discuten los factores que afectan la resistencia a la deformación permanente y la evolución de las ecuaciones matemáticas desarrolladas para predecir la deformación que experimentan estos materiales bajo carga cíclica. Un estado del conocimiento sobre el comportamiento resiliente de estos materiales es presentado en el primer artículo (Rondón y Reyes, 2007.Several studies have been conducted in pavement field for trying to understand the elastoplastic behavior experienced by granular materials under a cyclic load. This is the second out of two articles which show state-of-the-art of researches conducted in this field. Based on a wide literature review, this article accounts for the way how permanent strain phenomenon has been studied in granular materials used for creating base and sub-base layers of flexible pavement structures. Besides, this article displays and discusses factors which affect resistance to permanent strain and evolution of mathematical equations developed for predicting that strain experienced by these materials under a cyclic load. A state-of-the-art about resilient behavior of these materials has been presented in the first article (Rondón and Reyes, 2007.

  15. Small solar system bodies as granular systems

    Hestroffer, Daniel; Campo Bagatín, Adriano; Losert, Wolfgang; Opsomer, Eric; Sánchez, Paul; Scheeres, Daniel J.; Staron, Lydie; Taberlet, Nicolas; Yano, Hajime; Eggl, Siegfried; Lecomte, Charles-Edouard; Murdoch, Naomi; Radjai, Fahrang; Richardson, Derek C.; Salazar, Marcos; Schwartz, Stephen R.; Tanga, Paolo

    2017-06-01

    Asteroids and other Small Solar System Bodies (SSSBs) are currently of great scientific and even industrial interest. Asteroids exist as the permanent record of the formation of the Solar System and therefore hold many clues to its understanding as a whole, as well as insights into the formation of planetary bodies. Additionally, SSSBs are being investigated in the context of impact risks for the Earth, space situational awareness and their possible industrial exploitation (asteroid mining). In all these aspects, the knowledge of the geophysical characteristics of SSSB surface and internal structure are of great importance. Given their size, constitution, and the evidence that many SSSBs are not simple monoliths, these bodies should be studied and modelled as self-gravitating granular systems in general, or as granular systems in micro-gravity environments in particular contexts. As such, the study of the geophysical characteristics of SSSBs is a multi-disciplinary effort that lies at the crossroads between Granular Mechanics, Celestial Mechanics, Soil Mechanics, Aerospace Engineering and Computer Sciences.

  16. Iodine Gas Trapping using Granular Porous Bismuth

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Mansung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    {sup 129}I is a radionuclide with a very long half-life of 1.57 Χ 10{sup 7} years and has negative health effects to the human body. Therefore, the emission of {sup 129}I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous {sup 129}I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing {sup 129}I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping {sup 129}I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling.

  17. Iodine Gas Trapping using Granular Porous Bismuth

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il; Yim, Mansung

    2014-01-01

    129 I is a radionuclide with a very long half-life of 1.57 Χ 10 7 years and has negative health effects to the human body. Therefore, the emission of 129 I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous 129 I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing 129 I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping 129 I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling

  18. Propulsion via flexible flapping in granular media

    Peng, Zhiwei; Ding, Yang; Pietrzyk, Kyle; Elfring, Gwynn; Pak, On Shun

    2017-11-01

    Biological locomotion in nature is often achieved by the interaction between a flexible body and its surrounding medium. The interaction of a flexible body with granular media is less understood compared with viscous fluids partially due to its complex rheological properties. In this work, we explore the effect of flexibility on granular propulsion by considering a simple mechanical model in which a rigid rod is connected to a torsional spring that is under a displacement actuation using a granular resistive force theory. Through a combined numerical and asymptotic investigation, we characterize the propulsive dynamics of such a flexible flapper in relation to the actuation amplitude and spring stiffness, and we compare these dynamics with those observed in a viscous fluid. In addition, we demonstrate that the maximum possible propulsive force can be obtained in the steady propulsion limit with a finite spring stiffness and large actuation amplitude. These results may apply to the development of synthetic locomotive systems that exploit flexibility to move through complex terrestrial media. Funding for Z.P. and Y.D. was partially provided by NSFC 394 Grant No. 11672029 and NSAF-NSFC Grant No. U1530401.

  19. Rough – Granular Computing knowledge discovery models

    Mohammed M. Eissa

    2016-11-01

    Full Text Available Medical domain has become one of the most important areas of research in order to richness huge amounts of medical information about the symptoms of diseases and how to distinguish between them to diagnose it correctly. Knowledge discovery models play vital role in refinement and mining of medical indicators to help medical experts to settle treatment decisions. This paper introduces four hybrid Rough – Granular Computing knowledge discovery models based on Rough Sets Theory, Artificial Neural Networks, Genetic Algorithm and Rough Mereology Theory. A comparative analysis of various knowledge discovery models that use different knowledge discovery techniques for data pre-processing, reduction, and data mining supports medical experts to extract the main medical indicators, to reduce the misdiagnosis rates and to improve decision-making for medical diagnosis and treatment. The proposed models utilized two medical datasets: Coronary Heart Disease dataset and Hepatitis C Virus dataset. The main purpose of this paper was to explore and evaluate the proposed models based on Granular Computing methodology for knowledge extraction according to different evaluation criteria for classification of medical datasets. Another purpose is to make enhancement in the frame of KDD processes for supervised learning using Granular Computing methodology.

  20. "EGM" (Electrostatics of Granular Matter): A Space Station Experiment to Examine Natural Particulate Systems

    Marshall, J.; Sauke, T.; Buehler, M.; Farrell, W.; Green, R.; Birchenough, A.

    1999-09-01

    A granular-materials experiment is being developed for a 2002 launch for Space Station deployment. The experiment is funded by NASA HQ and managed through NASA Lewis Research Center. The experiment will examine electrostatic aggregation of coarse granular materials with the goals of (a) obtaining proof for an electrostatic dipole model of grain interactions, and (b) obtaining knowledge about the way aggregation affects the behavior of natural particulate masses: (1) in unconfined dispersions (clouds such as nebulae, aeolian dust palls, volcanic plumes), (2) in semi-confined, self-loaded masses as in fluidized flows (pyroclastic surges, avalanches) and compacted regolith, or (3) in semi-confined non-loaded masses as in dust layers adhering to solar cells or space suits on Mars. The experiment addresses both planetary/astrophysical issues as well as practical concerns for human exploration of Mars or other solar system bodies. Additional information is contained in the original.

  1. Linking Essential Tremor to the Cerebellum-Animal Model Evidence.

    Handforth, Adrian

    2016-06-01

    In this review, we hope to stimulate interest in animal models as opportunities to understand tremor mechanisms within the cerebellar system. We begin by considering the harmaline model of essential tremor (ET), which has ET-like anatomy and pharmacology. Harmaline induces the inferior olive (IO) to burst fire rhythmically, recruiting rhythmic activity in Purkinje cells (PCs) and deep cerebellar nuclei (DCN). This model has fostered the IO hypothesis of ET, which postulates that factors that promote excess IO, and hence PC complex spike synchrony, also promote tremor. In contrast, the PC hypothesis postulates that partial PC cell loss underlies tremor of ET. We describe models in which chronic partial PC loss is associated with tremor, such as the Weaver mouse, and others with PC loss that do not show tremor, such as the Purkinje cell degeneration mouse. We postulate that partial PC loss with tremor is associated with terminal axonal sprouting. We then discuss tremor that occurs with large lesions of the cerebellum in primates. This tremor has variable frequency and is an ataxic tremor not related to ET. Another tremor type that is not likely related to ET is tremor in mice with mutations that cause prolonged synaptic GABA action. This tremor is probably due to mistiming within cerebellar circuitry. In the final section, we catalog tremor models involving neurotransmitter and ion channel perturbations. Some appear to be related to the IO hypothesis of ET, while in others tremor may be ataxic or due to mistiming. In summary, we offer a tentative framework for classifying animal action tremor, such that various models may be considered potentially relevant to ET, subscribing to IO or PC hypotheses, or not likely relevant, as with mistiming or ataxic tremor. Considerable further research is needed to elucidate the mechanisms of tremor in animal models.

  2. Shear test on viscoelastic granular material using Contact Dynamics simulations

    Quezada, Juan Carlos; Sagnol, Loba; Chazallon, Cyrille

    2017-06-01

    By means of 3D contact dynamic simulations, the behavior of a viscoelastic granular material under shear loading is investigated. A viscoelastic fluid phase surrounding the solid particles is simulated by a contact model acting between them. This contact law was implemented in the LMGC90 software, based on the Burgers model. This model is able to simulate also the effect of creep relaxation. To validate the proposed contact model, several direct shear tests were performed, experimentally and numerically using the Leutner device. The numerical samples were created using spheres with two particle size distribution, each one identified for two layers from a road structure. Our results show a reasonable agreement between experimental and numerical data regarding the strain-stress evolution curves and the stress levels measured at failure. The proposed model can be used to simulate the mechanical behavior of multi-layer road structure and to study the influence of traffic on road deformation, cracking and particles pull-out induced by traffic loading.

  3. Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

    Mat Saad, Azlina; Aini Dahalan, Farrah; Ibrahim, Naimah; Yasina Yusuf, Sara; Aqlima Ahmad, Siti; Khalil, Khalilah Abdul

    2018-03-01

    Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic - anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

  4. The role of fluid viscosity in an immersed granular collapse

    Yang, Geng Chao; Kwok, Chung Yee; Sobral, Yuri Dumaresq

    2017-06-01

    Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM) and discrete element method (DEM). It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.

  5. The role of fluid viscosity in an immersed granular collapse

    Yang Geng Chao

    2017-01-01

    Full Text Available Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM and discrete element method (DEM. It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.

  6. Tunneling magnetoresistance in granular cermet films with particle size distribution

    Vovk, A.Ya.; Golub, V.O.; Malkinski, L.; Kravets, A.F.; Pogorily, A.M.; Shypil', O.V.

    2004-01-01

    The correlation between tunneling magnetoresistance (TMR) and field sensitivity (dMR/dH) for granular films (Co 50 Fe 50 ) x -(Al 2 O 3 ) 1-x was studied. The position of TMR maximum is shifted towards the lower x in the higher applied magnetic fields. Such a behavior was observed for metal granular nanocomposites but is first reported for granular cermets. However the highest dMR/dH was found for the compositions just below the percolation threshold

  7. A hydrodynamic model for granular material flows including segregation effects

    Gilberg, Dominik; Klar, Axel; Steiner, Konrad

    2017-06-01

    The simulation of granular flows including segregation effects in large industrial processes using particle methods is accurate, but very time-consuming. To overcome the long computation times a macroscopic model is a natural choice. Therefore, we couple a mixture theory based segregation model to a hydrodynamic model of Navier-Stokes-type, describing the flow behavior of the granular material. The granular flow model is a hybrid model derived from kinetic theory and a soil mechanical approach to cover the regime of fast dilute flow, as well as slow dense flow, where the density of the granular material is close to the maximum packing density. Originally, the segregation model has been formulated by Thornton and Gray for idealized avalanches. It is modified and adapted to be in the preferred form for the coupling. In the final coupled model the segregation process depends on the local state of the granular system. On the other hand, the granular system changes as differently mixed regions of the granular material differ i.e. in the packing density. For the modeling process the focus lies on dry granular material flows of two particle types differing only in size but can be easily extended to arbitrary granular mixtures of different particle size and density. To solve the coupled system a finite volume approach is used. To test the model the rotational mixing of small and large particles in a tumbler is simulated.

  8. Intrauterine Growth Restriction Alters the Postnatal Development of the Rat Cerebellum.

    McDougall, Annie R A; Wiradjaja, Vanny; Azhan, Aminath; Li, Anqi; Hale, Nadia; Wlodek, Mary E; Hooper, Stuart B; Wallace, Megan J; Tolcos, Mary

    2017-01-01

    Intrauterine growth restriction (IUGR) is a major cause of antenatal brain injury. We aimed to characterize cerebellar deficits following IUGR and to investigate the potential underlying cellular and molecular mechanisms. At embryonic day 18, pregnant rats underwent either sham surgery (controls; n = 23) or bilateral uterine vessel ligation to restrict blood flow to fetuses (IUGR; n = 20). Offspring were collected at postnatal day 2 (P2), P7, and P35. Body weights were reduced at P2, P7, and P35 in IUGR offspring (p < 0.05) compared with controls. At P7, the width of the external granule layer (EGL) was 30% greater in IUGR than control rats (p < 0.05); there was no difference in the width of the proliferative zone or in the density of Ki67-positive cells in the EGL. Bergmann glia were disorganized at P7 and P35 in IUGR pups, and by P35, there was a 10% decrease in Bergmann glial fiber density (p < 0.05) compared with controls. At P7, trophoblast antigen-2 (Trop2) mRNA and protein levels in the cerebellum were decreased by 88 and 40%, respectively, and astrotactin 1 mRNA levels were increased by 20% in the IUGR rats (p < 0.05) compared with controls; there was no difference in ASTN1 protein. The expressions of other factors known to regulate cerebellar development (astrotactin 2, brain-derived neurotrophic factor, erb-b2 receptor tyrosine kinase 4, neuregulin 1, sonic hedgehog and somatostatin) were not different between IUGR and control rats at P7 or P35. These data suggest that damage to the migratory scaffold (Bergmann glial fibers) and alterations in the genes that influence migration (Trop2 and Astn1) may underlie the deficits in postnatal cerebellar development following IUGR. © 2017 S. Karger AG, Basel.

  9. Effect of low frequency rTMS stimulation over lateral cerebellum: a FDG PET study

    Yoon, Eun Jin; Cho, Sang Soo; Bang, Soong Ae; Park, Hyun Soo; Kim, Sang Eun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2007-07-01

    Several lines of evidence suggested the involvement of cerebellum in cognitive function as well as motor function. Because of the measurement difficulty of functional connectivity, little is known about the underlying mechanism involvement of cerebellum in motor and cognitive function in living human brain. To understand the role of cerebellum within the neural network, we investigated the changes of neuronal activity elicited by the cerebellar repetitive transcranial magnetic stimulation (rTMS). 11 right-handed normal volunteers (age: 23.4{+-}2.5 y;6 males) were studied with FDG PET under two conditions; sham and 1Hz rTMS over left lateral cerebellum. With 10 min inter-block interval, three blocks of rTMS were started with the intravenous injection of [18F]FDG. In each block, 5min rTMS were delivered with an intensity of 90% of the resting motor threshold (RMT). Sham rTMS was delivered with same protocol but the coil was positioned perpendicular to the target area with 50% RMT. PET scans were acquired immediately after the rTMS stimulation. Sham and 1Hz rTMS images compared using paired t-test with SPM2. Inhibited neuronal activity compare to the sham condition were revealed in the stimulated left lateral cerebellum and orbitofrontal gyrus and right motor related areas (S1, SMA and posterior parietal cortex). While enhanced neuronal activity compare to the sham condition were revealed in the bilateral inferior frontal gyri including Broca's area and superior temporal gyrus including primary auditory cortex. Bilateral middle temporal, left precentral and right middle occipital gyri were also showed enhanced neuronal activity. This result showed that rTMS over left lateral cerebellum modulate direct vicinity of the targeted region and a large network of remote interconnected contralateral motor and ipsilateral language related brain regions. Present result provide evidence that cerebellum may contribute to language related cognitive function as well as motor

  10. Effect of low frequency rTMS stimulation over lateral cerebellum: a FDG PET study

    Yoon, Eun Jin; Cho, Sang Soo; Bang, Soong Ae; Park, Hyun Soo; Kim, Sang Eun

    2007-01-01

    Several lines of evidence suggested the involvement of cerebellum in cognitive function as well as motor function. Because of the measurement difficulty of functional connectivity, little is known about the underlying mechanism involvement of cerebellum in motor and cognitive function in living human brain. To understand the role of cerebellum within the neural network, we investigated the changes of neuronal activity elicited by the cerebellar repetitive transcranial magnetic stimulation (rTMS). 11 right-handed normal volunteers (age: 23.4±2.5 y;6 males) were studied with FDG PET under two conditions; sham and 1Hz rTMS over left lateral cerebellum. With 10 min inter-block interval, three blocks of rTMS were started with the intravenous injection of [18F]FDG. In each block, 5min rTMS were delivered with an intensity of 90% of the resting motor threshold (RMT). Sham rTMS was delivered with same protocol but the coil was positioned perpendicular to the target area with 50% RMT. PET scans were acquired immediately after the rTMS stimulation. Sham and 1Hz rTMS images compared using paired t-test with SPM2. Inhibited neuronal activity compare to the sham condition were revealed in the stimulated left lateral cerebellum and orbitofrontal gyrus and right motor related areas (S1, SMA and posterior parietal cortex). While enhanced neuronal activity compare to the sham condition were revealed in the bilateral inferior frontal gyri including Broca's area and superior temporal gyrus including primary auditory cortex. Bilateral middle temporal, left precentral and right middle occipital gyri were also showed enhanced neuronal activity. This result showed that rTMS over left lateral cerebellum modulate direct vicinity of the targeted region and a large network of remote interconnected contralateral motor and ipsilateral language related brain regions. Present result provide evidence that cerebellum may contribute to language related cognitive function as well as motor control

  11. Potassium Bromate-induced Changes in the Adult Mouse Cerebellum Are Ameliorated by Vanillin.

    Ben Saad, Hajer; Driss, Dorra; Jaballi, Imen; Ghozzi, Hanen; Boudawara, Ons; Droguet, Michael; Magné, Christian; Nasri, Monsef; Zeghal, Khaled Mounir; Hakim, Ahmed; Ben Amara, Ibtissem

    2018-02-01

    The current study aimed to elucidate the effect of vanillin on behavioral changes, oxidative stress, and histopathological changes induced by potassium bromate (KBrO3), an environmental pollutant, in the cerebellum of adult mice. The animals were divided into four groups: group 1 served as a control, group 2 received KBrO3, group 3 received KBrO3 and vanillin, and group 4 received only vanillin. We then measured behavioral changes, oxidative stress, and molecular and histological changes in the cerebellum. We observed significant behavioral changes in KBrO3-exposed mice. When investigating redox homeostasis in the cerebellum, we found that mice treated with KBrO3 had increased lipid peroxidation and protein oxidation in the cerebellum. These effects were accompanied by decreased Na+-K+ and Mg2+ ATPase activity and antioxidant enzyme gene expression when compared to the control group. Additionally, there was a significant increase in cytokine gene expression in KBrO3-treated mice. Microscopy revealed that KBrO3 intoxication resulted in numerous degenerative changes in the cerebellum that were substantially ameliorated by vanillin supplementation. Co-administration of vanillin blocked the biochemical and molecular anomalies induced by KBrO3. Our results demonstrate that vanillin is a potential therapeutic agent for oxidative stress associated with neurodegenerative diseases. Copyright © 2018 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  12. The pedunculopontine tegmental nucleus as a motor and cognitive interface between the cerebellum and basal ganglia

    Fumika Mori

    2016-11-01

    Full Text Available As an important component of ascending activating systems, brainstem cholinergic neurons in the pedunculopontine tegmental nucleus (PPTg are involved in the regulation of motor control (locomotion, posture and gaze and cognitive processes (attention, learning, and memory. The PPTg is highly interconnected with several regions of the basal ganglia, and one of its key functions is to regulate and relay activity from the basal ganglia. Together, they have been implicated in the motor control system (such as voluntary movement initiation or inhibition, and modulate aspects of executive function (such as motivation. In addition to its intimate connection with the basal ganglia, projections from the PPTg to the cerebellum have been recently reported to synaptically activate the deep cerebellar nuclei. Classically, the cerebellum and basal ganglia were regarded as forming separated anatomical loops that play a distinct functional role in motor and cognitive behavioral control. Here, we suggest that the PPTg may also act as an interface device between the basal ganglia and cerebellum. As such, part of the therapeutic effect of PPTg deep brain stimulation to relieve gait freezing and postural instability in advanced Parkinson’s disease patients might also involve modulation of the cerebellum. We review the anatomical position and role of the PPTg in the pathway of basal ganglia and cerebellum in relation to motor control, cognitive function, and Parkinson’s disease.

  13. The Pedunculopontine Tegmental Nucleus as a Motor and Cognitive Interface between the Cerebellum and Basal Ganglia.

    Mori, Fumika; Okada, Ken-Ichi; Nomura, Taishin; Kobayashi, Yasushi

    2016-01-01

    As an important component of ascending activating systems, brainstem cholinergic neurons in the pedunculopontine tegmental nucleus (PPTg) are involved in the regulation of motor control (locomotion, posture and gaze) and cognitive processes (attention, learning and memory). The PPTg is highly interconnected with several regions of the basal ganglia, and one of its key functions is to regulate and relay activity from the basal ganglia. Together, they have been implicated in the motor control system (such as voluntary movement initiation or inhibition), and modulate aspects of executive function (such as motivation). In addition to its intimate connection with the basal ganglia, projections from the PPTg to the cerebellum have been recently reported to synaptically activate the deep cerebellar nuclei. Classically, the cerebellum and basal ganglia were regarded as forming separated anatomical loops that play a distinct functional role in motor and cognitive behavioral control. Here, we suggest that the PPTg may also act as an interface device between the basal ganglia and cerebellum. As such, part of the therapeutic effect of PPTg deep brain stimulation (DBS) to relieve gait freezing and postural instability in advanced Parkinson's disease (PD) patients might also involve modulation of the cerebellum. We review the anatomical position and role of the PPTg in the pathway of basal ganglia and cerebellum in relation to motor control, cognitive function and PD.

  14. The cerebro-cerebellum: Could it be loci of forward models?

    Ishikawa, Takahiro; Tomatsu, Saeka; Izawa, Jun; Kakei, Shinji

    2016-03-01

    It is widely accepted that the cerebellum acquires and maintain internal models for motor control. An internal model simulates mapping between a set of causes and effects. There are two candidates of cerebellar internal models, forward models and inverse models. A forward model transforms a motor command into a prediction of the sensory consequences of a movement. In contrast, an inverse model inverts the information flow of the forward model. Despite the clearly different formulations of the two internal models, it is still controversial whether the cerebro-cerebellum, the phylogenetically newer part of the cerebellum, provides inverse models or forward models for voluntary limb movements or other higher brain functions. In this article, we review physiological and morphological evidence that suggests the existence in the cerebro-cerebellum of a forward model for limb movement. We will also discuss how the characteristic input-output organization of the cerebro-cerebellum may contribute to forward models for non-motor higher brain functions. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  15. Generalized role for the cerebellum in encoding internal models: evidence from semantic processing.

    Moberget, Torgeir; Gullesen, Eva Hilland; Andersson, Stein; Ivry, Richard B; Endestad, Tor

    2014-02-19

    The striking homogeneity of cerebellar microanatomy is strongly suggestive of a corresponding uniformity of function. Consequently, theoretical models of the cerebellum's role in motor control should offer important clues regarding cerebellar contributions to cognition. One such influential theory holds that the cerebellum encodes internal models, neural representations of the context-specific dynamic properties of an object, to facilitate predictive control when manipulating the object. The present study examined whether this theoretical construct can shed light on the contribution of the cerebellum to language processing. We reasoned that the cerebellum might perform a similar coordinative function when the context provided by the initial part of a sentence can be highly predictive of the end of the sentence. Using functional MRI in humans we tested two predictions derived from this hypothesis, building on previous neuroimaging studies of internal models in motor control. First, focal cerebellar activation-reflecting the operation of acquired internal models-should be enhanced when the linguistic context leads terminal words to be predictable. Second, more widespread activation should be observed when such predictions are violated, reflecting the processing of error signals that can be used to update internal models. Both predictions were confirmed, with predictability and prediction violations associated with increased blood oxygenation level-dependent signal in the posterior cerebellum (Crus I/II). Our results provide further evidence for cerebellar involvement in predictive language processing and suggest that the notion of cerebellar internal models may be extended to the language domain.

  16. The mystery of the cerebellum: clues from experimental and clinical observations.

    Lawrenson, Charlotte; Bares, Martin; Kamondi, Anita; Kovács, Andrea; Lumb, Bridget; Apps, Richard; Filip, Pavel; Manto, Mario

    2018-01-01

    The cerebellum has a striking homogeneous cytoarchitecture and participates in both motor and non-motor domains. Indeed, a wealth of evidence from neuroanatomical, electrophysiological, neuroimaging and clinical studies has substantially modified our traditional view on the cerebellum as a sole calibrator of sensorimotor functions. Despite the major advances of the last four decades of cerebellar research, outstanding questions remain regarding the mechanisms and functions of the cerebellar circuitry. We discuss major clues from both experimental and clinical studies, with a focus on rodent models in fear behaviour, on the role of the cerebellum in motor control, on cerebellar contributions to timing and our appraisal of the pathogenesis of cerebellar tremor. The cerebellum occupies a central position to optimize behaviour, motor control, timing procedures and to prevent body oscillations. More than ever, the cerebellum is now considered as a major actor on the scene of disorders affecting the CNS, extending from motor disorders to cognitive and affective disorders. However, the respective roles of the mossy fibres, the climbing fibres, cerebellar cortex and cerebellar nuclei remains unknown or partially known at best in most cases. Research is now moving towards a better definition of the roles of cerebellar modules and microzones. This will impact on the management of cerebellar disorders.

  17. Arrangement and Applying of Movement Patterns in the Cerebellum Based on Semi-supervised Learning.

    Solouki, Saeed; Pooyan, Mohammad

    2016-06-01

    Biological control systems have long been studied as a possible inspiration for the construction of robotic controllers. The cerebellum is known to be involved in the production and learning of smooth, coordinated movements. Therefore, highly regular structure of the cerebellum has been in the core of attention in theoretical and computational modeling. However, most of these models reflect some special features of the cerebellum without regarding the whole motor command computational process. In this paper, we try to make a logical relation between the most significant models of the cerebellum and introduce a new learning strategy to arrange the movement patterns: cerebellar modular arrangement and applying of movement patterns based on semi-supervised learning (CMAPS). We assume here the cerebellum like a big archive of patterns that has an efficient organization to classify and recall them. The main idea is to achieve an optimal use of memory locations by more than just a supervised learning and classification algorithm. Surely, more experimental and physiological researches are needed to confirm our hypothesis.

  18. Sensors for the CMS High Granularity Calorimeter

    Maier, Andreas Alexander

    2017-01-01

    The CMS experiment is currently developing high granularity calorimeter endcapsfor its HL-LHC upgrade. The design foresees silicon sensors as the active material for the high radiation region close to the beampipe. Regions of lower radiation are additionally equipped with plastic scintillator tiles. This technology is similar to the calorimeter prototypes developed in the framework of the Linear Collider by the CALICE collaboration. The current status of the silicon sensor development is presented. Results of single diode measurements are shown as well as tests of full 6-inch hexagonal sensor wafers. A short summary of test beam results concludes the article.

  19. Modelling of dc characteristics for granular semiconductors

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey

    2010-01-01

    The dc characteristics of granular n-type semiconductors are calculated analytically with the drift-diffusion theory. Electronic trapping at the grain boundaries (GBs) is taken into account. The use of quadratic and linear GB potential profiles in the calculation is compared. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is excellent in a large voltage range. The results show that electronic trapping at the GBs has a remarkable effect on the highly nonlinear I-V characteristics of the material.

  20. Modelling of dc characteristics for granular semiconductors

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey, E-mail: aapo.varpula@tkk.f [Department of Micro and Nanosciences, Aalto University, PO Box 13500, FI-00076 Aalto, Espoo (Finland)

    2010-11-01

    The dc characteristics of granular n-type semiconductors are calculated analytically with the drift-diffusion theory. Electronic trapping at the grain boundaries (GBs) is taken into account. The use of quadratic and linear GB potential profiles in the calculation is compared. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is excellent in a large voltage range. The results show that electronic trapping at the GBs has a remarkable effect on the highly nonlinear I-V characteristics of the material.

  1. Special relativity induced by granular space

    Jizba, Petr; Scardigli, Fabio

    2013-01-01

    We show that the special relativistic dynamics, when combined with quantum mechanics and the concept of superstatistics, can be interpreted as arising from two interlocked non-relativistic stochastic processes that operate at different energy scales. This framework leads to Feynman amplitudes that are, in the Euclidean regime, identical to the transition probability of a Brownian particle propagating through a granular space. For illustration we consider the dynamics and the propagator of a Klein-Gordon particle. Implications for deformed special relativity, quantum field theory, quantum gravity and cosmology are also discussed. (orig.)

  2. Brine Transport Experiments in Granular Salt

    Jordan, Amy B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Caporuscio, Florie Andre [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-06

    To gain confidence in the predictive capability of numerical models, experimental validation must be performed to ensure that parameters and processes are correctly simulated. The laboratory investigations presented herein aim to address knowledge gaps for heat-generating nuclear waste (HGNW) disposal in bedded salt that remain after examination of prior field and laboratory test data. Primarily, we are interested in better constraining the thermal, hydrological, and physicochemical behavior of brine, water vapor, and salt when moist salt is heated. The target of this work is to use run-of-mine (RoM) salt; however during FY2015 progress was made using high-purity, granular sodium chloride.

  3. Unifying Suspension and Granular flows near Jamming

    DeGiuli Eric

    2017-01-01

    Full Text Available Rheological properties of dense flows of hard particles are singular as one approaches the jamming threshold where flow ceases, both for granular flows dominated by inertia, and for over-damped suspensions. Concomitantly, the lengthscale characterizing velocity correlations appears to diverge at jamming. Here we review a theoretical framework that gives a scaling description of stationary flows of frictionless particles. Our analysis applies both to suspensions and inertial flows of hard particles. We report numerical results in support of the theory, and show the phase diagram that results when friction is added, delineating the regime of validity of the frictionless theory.

  4. Shock propagation in locally driven granular systems

    Joy, Jilmy P.; Pathak, Sudhir N.; Das, Dibyendu; Rajesh, R.

    2017-09-01

    We study shock propagation in a system of initially stationary hard spheres that is driven by a continuous injection of particles at the origin. The disturbance created by the injection of energy spreads radially outward through collisions between particles. Using scaling arguments, we determine the exponent characterizing the power-law growth of this disturbance in all dimensions. The scaling functions describing the various physical quantities are determined using large-scale event-driven simulations in two and three dimensions for both elastic and inelastic systems. The results are shown to describe well the data from two different experiments on granular systems that are similarly driven.

  5. On the velocity distributions of granular gases

    Polito, A.M.M.; Rocha Filho, T.M.; Figueiredo, A.

    2009-01-01

    We present a new approach to determine velocity distributions in granular gases to improve the Sonine polynomial expansion of the velocity distribution function, at higher inelasticities, for the homogeneous cooling regime of inelastic hard spheres. The perturbative consistency is recovered using a new set of dynamical variables based on the characteristic function and we illustrate our approach by computing the first four Sonine coefficients for moderate and high inelasticities. The analytical coefficients are compared with molecular dynamics simulations results and with a previous approach by Huthmann et al.

  6. Density-wave fronts on the brink of wet granular condensation

    Huang, Kai; Zippelius, Andreas; Sand lab @ University of Bayreuth Team

    2017-11-01

    From sand dunes to Faraday heaping, driven granular matter, i.e., large agglomeration of macroscopic particles, is rich pattern forming system. When a granular material is partially wet (e.g., wet sand on the beach), a different pattern forming scenario arises due to the cohesive particle-particle interactions. Here, we focus on the formation of density-wave fronts in an oscillated wet granular layer undergoing a gas-liquid-like transition. The threshold of the instability is governed by the amplitude of the vertical vibrations. Fronts, which are curved into a spiral shape, propagate coherently along the circular rim of the container with leading edges. They are stable beyond a critical distance from the container center. Based on the measurement of the critical distance and the rotation frequency, we propose a model for the pattern formation by considering the competition between the time scale for the collapse of cohesive particles and that of the energy injection resisting this process. Deutsche Forschungsgemeinschaft (Grant No. HU1939 4-1).

  7. A Grey Wolf Optimizer for Modular Granular Neural Networks for Human Recognition

    Daniela Sánchez

    2017-01-01

    Full Text Available A grey wolf optimizer for modular neural network (MNN with a granular approach is proposed. The proposed method performs optimal granulation of data and design of modular neural networks architectures to perform human recognition, and to prove its effectiveness benchmark databases of ear, iris, and face biometric measures are used to perform tests and comparisons against other works. The design of a modular granular neural network (MGNN consists in finding optimal parameters of its architecture; these parameters are the number of subgranules, percentage of data for the training phase, learning algorithm, goal error, number of hidden layers, and their number of neurons. Nowadays, there is a great variety of approaches and new techniques within the evolutionary computing area, and these approaches and techniques have emerged to help find optimal solutions to problems or models and bioinspired algorithms are part of this area. In this work a grey wolf optimizer is proposed for the design of modular granular neural networks, and the results are compared against a genetic algorithm and a firefly algorithm in order to know which of these techniques provides better results when applied to human recognition.

  8. Biosorption of Acid Yellow 17 from aqueous solution by non-living aerobic granular sludge

    Gao Jingfeng; Zhang Qian; Su Kai; Chen Ranni; Peng Yongzhen

    2010-01-01

    Batch biosorption experiments were carried out for the removal of Acid Yellow 17 from aqueous solution using non-living aerobic granular sludge as an effective biosorbent. The effects of solution pH value, biosorbent dosage, initial Acid Yellow 17 concentration, NaCl concentration and temperature on the biosorption were investigated. The experimental results indicate that this process was highly dependent on pH value and the pH value of 2.0 was favorable. The Temkin isotherm was more applicable for describing the biosorption equilibrium at the whole concentration range than the Freundlich and Langmuir isotherm. The results of kinetics study show that the pseudo-second-order model fitted to the experimental data well. Both intraparticle diffusion and boundary layer diffusion might affect the biosorption rate. Thermodynamic studies demonstrate that the biosorption process was spontaneous and exothermic. The FTIR analysis before and after Acid Yellow 17 binding indicated that functional groups such as amine, hydroxyl, carboxyl and either on the non-living aerobic granular sludge would be the active binding sites for the biosorption of the studied dye. These results show that non-living aerobic granular sludge could be effectively used as a low-cost and alternative biosorbent for the removal of Acid Yellow 17 dye from wastewater.

  9. Seawater-based wastewater accelerates development of aerobic granular sludge: A laboratory proof-of-concept.

    Li, Xiling; Luo, Jinghai; Guo, Gang; Mackey, Hamish R; Hao, Tianwei; Chen, Guanghao

    2017-05-15

    This study aimed to develop an aerobic granular sludge process for the efficient treatment of highly saline wastewater and understand the granulation process in a seawater-based multi-ion matrix. Five identical sequencing batch airlift reactors (SBARs) are used to treat synthetic saline sewage with different proportions of real seawater (0%-100%). The results confirm that aerobic granular sludge can be successfully developed with various proportions of seawater up to 100% and show that seawater not only significantly accelerates granulation but also generates stronger granular structures than does freshwater. The increased presence of gel-forming alginate-like exopolysaccharides in the granules explains why a greater proportion of seawater leads to higher density and improves the cohesive strength of the granules. SEM-EDX analysis further revealed substantial presence of both Ca 2+ and Mg 2+ phosphate in the granule core as well as in the outer layers providing extra bridging forces in addition to alginate-like exopolysaccharides for accelerating the granule formation and maintaining the structure. It is hoped that this work could explore another approach for saline sewage treatment and bring some clues for the mystery of granulation mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Preliminary morphological and morphometric study of rat cerebellum following sodium arsenite exposure during rapid brain growth (RBG) period

    Dhar, Pushpa; Mohari, Nivedita; Mehra, Raj D.

    2007-01-01

    The effects of arsenic exposure during rapid brain growth (RBG) period were studied in rat brains with emphasis on the Purkinje cells of the cerebellum. The RBG period in rats extends from postnatal day 4 (PND 4) to postnatal day 10 (PND 10) and is reported to be highly vulnerable to environmental insults. Mother reared Wistar rat pups were administered intraperitoneal injections (i.p.) of sodium arsenite (aqueous solution) in doses of 1.0, 1.5 and 2.0 mg/kg body weight (bw) to groups II, III and IV (n = 6 animals/group) from PND 4 to 10 (sub acute). Control animals (group I) received distilled water by the same route. On PND 11, the animals were perfusion fixed with 4% paraformaldehyde in 0.1 M phosphate buffer (PB) with pH 7.4. The cerebellum obtained from these animals was post-fixed and processed for paraffin embedding. Besides studying the morphological characteristics of Purkinje cells in cresyl violet (CV) stained paraffin sections (10 μm), morphometric analysis of Purkinje cells was carried out using Image Analysis System (Image Proplus software version 4.5) attached to Nikon Microphot-FX microscope. The results showed that on PND 11, the Purkinje cells were arranged in multiple layers extending from Purkinje cell layer (PL) to outer part of granule cell layer (GL) in experimental animals (contrary to monolayer arrangement within PL in control animals). Also, delayed maturation (well defined apical cytoplasmic cones and intense basal basophilia) was evident in Purkinje cells of experimental animals on PND 11. The mean Purkinje cell nuclear area was significantly increased in the arsenic treated animals compared to the control animals. The observations of the present study (faulty migration, delayed maturation and alteration in nuclear area measurements of Purkinje cells subsequent to arsenic exposure) thus provided the morphological evidence of structural alterations subsequent to arsenite induced developmental neurotoxicity which could be presumed to be

  11. Origin of the resistivity minima in granular superconductors

    Simanek, E.

    1982-01-01

    The recently observed minima in the temperature dependence of the electrical resistivity of a granular superconductor are explained with use of a percolation model of a disordered granular array, which takes into account the electrostatic charging energy. The thermally activated tunneling of Cooper pairs is shown to play an important role in the interpretation of the experimental data on tin films

  12. Granular motor in the non-Brownian limit

    Oyarte Galvez, Loreto Alejandra; van der Meer, Roger M.

    2016-01-01

    In this work we experimentally study a granular rotor which is similar to the famous Smoluchowski–Feynman device and which consists of a rotor with four vanes immersed in a granular gas. Each side of the vanes can be composed of two different materials, creating a rotational asymmetry and turning

  13. Nonlinear instability and convection in a vertically vibrated granular bed

    Shukla, P.; Ansari, I.H.; van der Meer, Roger M.; Lohse, Detlef; Alam, M.

    2014-01-01

    The nonlinear instability of the density-inverted granular Leidenfrost state and the resulting convective motion in strongly shaken granular matter are analysed via a weakly nonlinear analysis of the hydrodynamic equations. The base state is assumed to be quasi-steady and the effect of harmonic

  14. USE OF GRANULAR GRAPHITE FOR ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE

    Granular graphite is a potential electrode material for the electrochemical remediation of refractory chlorinated organic compounds such as trichloroethylene (TCE). However, the use of granular graphite can complicate the experimental results. On one hand, up to 99% of TCE was re...

  15. Surface effects in the acetylation of granular potato starch

    Steeneken, P.A.M.; Woortman, A.J.J.

    2008-01-01

    The occurrence of surface effects in the acetylation of granular potato starch with acetic anhydride to degrees of substitution 0.04-0.2 was studied by two different approaches. The first approach involved the fractionation of granular starch acetates into five different size classes and analysis of

  16. Long-range interactions in dilute granular systems

    Müller, M.K

    2008-01-01

    In this thesis, on purpose, we focussed on the most challenging, longest ranging potentials. We analyzed granular media of low densities obeying 1/r long-range interaction potentials between the granules. Such systems are termed granular gases and differ in their behavior from ordinary gases by

  17. Influence of granular strontium chloride as additives on some ...

    Influence of granular strontium chloride as additives on some electrical and mechanical properties for pure polyvinyl alcohol. A B Elaydy M Hafez ... Keywords. Polyvinyl-alcohol (PVA); granular strontium chloride, SrCl2; a.c. electrical conductivity; dielectric constant; dielectric loss; Young's modulus; creep relaxation curve.

  18. Large mid-esophageal granular cell tumor: benign versus malignant

    Prarthana Roselil Christopher

    2015-06-01

    Full Text Available Granular cell tumors are rare soft tissue neoplasms, among which only 2% are malignant, arising from nervous tissue. Here we present a case of a large esophageal granular cell tumor with benign histopathological features which metastasized to the liver, but showing on positron emission tomography-computerized tomography standardized uptake value suggestive of a benign lesion.

  19. Adsorption Study of Cobalt on Treated Granular Activated Carbon

    Y. V. Hete; S. B. Gholase; R. U. Khope

    2012-01-01

    This study is carried out for the removal of cobalt from aqueous solution using granular activated carbon in combination with p-nitro benzoic acid at temperature 25±1 °C. The adsorption isotherm of cobalt on granular activated carbon has been determined and the data fitted reasonably well to the Langmuir and Freundlich isotherm for activated carbon.

  20. Adsorption Study of Cobalt on Treated Granular Activated Carbon

    Y. V. Hete

    2012-01-01

    Full Text Available This study is carried out for the removal of cobalt from aqueous solution using granular activated carbon in combination with p-nitro benzoic acid at temperature 25±1 °C. The adsorption isotherm of cobalt on granular activated carbon has been determined and the data fitted reasonably well to the Langmuir and Freundlich isotherm for activated carbon.

  1. Density-Driven segregation in Binary and Ternary Granular Systems

    Windows-Yule, Kit; Parker, David

    2015-01-01

    We present a first experimental study of density-induced segregation within a three-dimensional, vibrofluidised, ternary granular system. Using Positron Emission Particle Tracking (PEPT), we study the steady-state particle distributions achieved by binary and ternary granular beds under a variety of

  2. Fast voltage-sensitive dye imaging of excitatory and inhibitory synaptic transmission in the rat granular retrosplenial cortex.

    Nixima, Ken'ichi; Okanoya, Kazuo; Ichinohe, Noritaka; Kurotani, Tohru

    2017-09-01

    Rodent granular retrosplenial cortex (GRS) has dense connections between the anterior thalamic nuclei (ATN) and hippocampal formation. GRS superficial pyramidal neurons exhibit distinctive late spiking (LS) firing property and form patchy clusters with prominent apical dendritic bundles. The aim of this study was to investigate spatiotemporal dynamics of signal transduction in the GRS induced by ATN afferent stimulation by using fast voltage-sensitive dye imaging in rat brain slices. In coronal slices, layer 1a stimulation, which presumably activated thalamic fibers, evoked propagation of excitatory synaptic signals from layers 2-4 to layers 5-6 in a direction perpendicular to the layer axis, followed by transverse signal propagation within each layer. In the presence of ionotropic glutamate receptor antagonists, inhibitory responses were observed in superficial layers, induced by direct activation of inhibitory interneurons in layer 1. In horizontal slices, excitatory signals in deep layers propagated transversely mainly from posterior to anterior via superficial layers. Cortical inhibitory responses upon layer 1a stimulation in horizontal slices were weaker than those in the coronal slices. Observed differences between coronal and horizontal planes suggest anisotropy of the intracortical circuitry. In conclusion, ATN inputs are processed differently in coronal and horizontal planes of the GRS and then conveyed to other cortical areas. In both planes, GRS superficial layers play an important role in signal propagation, which suggests that superficial neuronal cascade is crucial in the integration of multiple information sources. NEW & NOTEWORTHY Superficial neurons in the rat granular retrosplenial cortex (GRS) show distinctive late-spiking (LS) firing property. However, little is known about spatiotemporal dynamics of signal transduction in the GRS. We demonstrated LS neuron network relaying thalamic inputs to deep layers and anisotropic distribution of

  3. Statistical shape (ASM) and appearance (AAM) models for the segmentation of the cerebellum in fetal ultrasound

    Reyes López, Misael; Arámbula Cosío, Fernando

    2017-11-01

    The cerebellum is an important structure to determine the gestational age of the fetus, moreover most of the abnormalities it presents are related to growth disorders. In this work, we present the results of the segmentation of the fetal cerebellum applying statistical shape and appearance models. Both models were tested on ultrasound images of the fetal brain taken from 23 pregnant women, between 18 and 24 gestational weeks. The accuracy results obtained on 11 ultrasound images show a mean Hausdorff distance of 6.08 mm between the manual segmentation and the segmentation using active shape model, and a mean Hausdorff distance of 7.54 mm between the manual segmentation and the segmentation using active appearance model. The reported results demonstrate that the active shape model is more robust in the segmentation of the fetal cerebellum in ultrasound images.

  4. Differentiating Patients with Parkinson's Disease from Normal Controls Using Gray Matter in the Cerebellum.

    Zeng, Ling-Li; Xie, Liang; Shen, Hui; Luo, Zhiguo; Fang, Peng; Hou, Yanan; Tang, Beisha; Wu, Tao; Hu, Dewen

    2017-02-01

    Parkinson's disease (PD) is one of the most common neurodegenerative disorders in the world. Previous studies have focused on the basal ganglia and cerebral cortices. To date, the cerebellum has not been systematically investigated in patients with PD. In the current study, 45 probable PD patients and 40 age- and gender-matched healthy controls underwent structural magnetic resonance imaging, and we used support vector machines combining with voxel-based morphometry to explore the cerebellar structural changes in the probable PD patients relative to healthy controls. The results revealed that the gray matter alterations were primarily located within the cerebellar Crus I, implying a possible important role of this region in PD. Furthermore, the gray matter alterations in the cerebellum could differentiate the probable PD patients from healthy controls with accuracies of more than 95 % (p cerebellum in the clinical diagnosis of PD.

  5. MR measurement of normal brainstem cerebellum and corpus callosum on midsagittal section

    Kogame, Saeko; Sawa, S.; Inoue, Yuichi; Fukuda, Teruo; Tada, Takuji; Shakudo, Miyuki; Yahata, Kunifumi; Shimizu, Hiroshi; Onoyama, Yasuhito.

    1989-01-01

    The dimensions of the brainstem, cerebellum and corpus callosum were measured on magnetic resonance (MR) images with sagittal spin-echo sequence. Eighty-two normal adults (average 49.6 years old) were measured. The mesencephalic, pontine or cerebellar diamaters and lengths could be measured more accurately and reproducibly than medullary diameter and length. The anterio-posterior diameter of the pons and the cerebellum was 23.2±1.4 mm and 26.4±2.5 mm respectively. The length of the pons and the cerebellum was 27.8±2 mm and 45.8±3.5 mm respectively. We have observed focal thinning at the body of corpus callosum in 73%. This narrowing is almost unquestionably a normal variant. (author)

  6. Alcohol exposure decreases CREB binding protein expression and histone acetylation in the developing cerebellum.

    Weixiang Guo

    Full Text Available Fetal alcohol exposure affects 1 in 100 children making it the leading cause of mental retardation in the US. It has long been known that alcohol affects cerebellum development and function. However, the underlying molecular mechanism is unclear.We demonstrate that CREB binding protein (CBP is widely expressed in granule and Purkinje neurons of the developing cerebellar cortex of naïve rats. We also show that exposure to ethanol during the 3(rd trimester-equivalent of human pregnancy reduces CBP levels. CBP is a histone acetyltransferase, a component of the epigenetic mechanism controlling neuronal gene expression. We further demonstrate that the acetylation of both histone H3 and H4 is reduced in the cerebellum of ethanol-treated rats.These findings indicate that ethanol exposure decreases the expression and function of CBP in the developing cerebellum. This effect of ethanol may be responsible for the motor coordination deficits that characterize fetal alcohol spectrum disorders.

  7. Critical phenomenon of granular flow on a conveyor belt.

    De-Song, Bao; Xun-Sheng, Zhang; Guang-Lei, Xu; Zheng-Quan, Pan; Xiao-Wei, Tang; Kun-Quan, Lu

    2003-06-01

    The relationship between the granular wafer movement on a two-dimensional conveyor belt and the size of the exit together with the velocity of the conveyor belt has been studied in the experiment. The result shows that there is a critical speed v(c) for the granular flow when the exit width d is fixed (where d=R/D, D being the diameter of a granular wafers). When vv(c), the flow rate Q is described as Q=Crho(v)(beta)(d-k)(3/2). These are the effects of the interaction among the granular wafers and the change of the states of the granular flow due to the changing of the speed or the exit width d.

  8. Lizard locomotion in heterogeneous granular media

    Schiebel, Perrin; Goldman, Daniel

    2014-03-01

    Locomotion strategies in heterogeneous granular environments (common substrates in deserts), are relatively unexplored. The zebra-tailed lizard (C. draconoides) is a useful model organism for such studies owing to its exceptional ability to navigate a variety of desert habitats at impressive speed (up to 50 body-lengths per second) using both quadrapedal and bidepal gaits. In laboratory experiments, we challenge the lizards to run across a field of boulders (2.54 cm diameter glass spheres or 3.8 cm 3D printed spheres) placed in a lattice pattern and embedded in a loosely packed granular medium of 0.3 mm diameter glass particles. Locomotion kinematics of the lizard are recorded using high speed cameras, with and without the scatterers. The data reveals that unlike the lizard's typical quadrupedal locomotion using a diagonal gait, when scatterers are present the lizard is most successful when using a bipedal gait, with a raised center of mass (CoM). We propose that the kinematics of bipedal running in conjunction with the lizard's long toes and compliant hind foot are the keys to this lizard's successful locomotion in the presence of such obstacles. NSF PoLS

  9. Wrinkles, folds, and plasticity in granular rafts

    Jambon-Puillet, Etienne; Josserand, Christophe; Protière, Suzie

    2017-09-01

    We investigate the mechanical response of a compressed monolayer of large and dense particles at a liquid-fluid interface: a granular raft. Upon compression, rafts first wrinkle; then, as the confinement increases, the deformation localizes in a unique fold. This characteristic buckling pattern is usually associated with floating elastic sheets, and as a result, particle laden interfaces are often modeled as such. Here, we push this analogy to its limits by comparing quantitative measurements of the raft morphology to a theoretical continuous elastic model of the interface. We show that, although powerful to describe the wrinkle wavelength, the wrinkle-to-fold transition, and the fold shape, this elastic description does not capture the finer details of the experiment. We describe an unpredicted secondary wavelength, a compression discrepancy with the model, and a hysteretic behavior during compression cycles, all of which are a signature of the intrinsic discrete and frictional nature of granular rafts. It suggests also that these composite materials exhibit both plastic transition and jamming dynamics.

  10. Large granular lymphocytic leukaemia pathogenesis and management.

    Dearden, Claire

    2011-02-01

    The WHO classification recognises three distinct disorders of large granular lymphocytes: T-cell large granular lymphocytic leukaemia (T-LGL), chronic lymphoproliferative disorders of NK-cells (CLPD-NK) and agressive NK-cell leukaemia. Despite the different cell of origin, there is considerable overlap between T-LGL and CLPD-NK in terms of clinical presentation and therapy. Many patients are asymptomatic and do not require treatment. Therapy, with immunosuppressant agents such as low dose methotrexate or ciclosporin, is usually indicated to correct cytopenias. In contrast, aggressive NK-cell leukaemia and the rare CD56(+) aggressive T-LGL leukaemia follow a fulminant clinical course, affect younger individuals and require more intensive combination chemotherapy followed by allogeneic stem cell transplant in eligible patients. The relative rarity of these disorders means that there have been few clinical trials to inform management. However, there is now considerable interest in the pathogenesis of the chronic LGL leukaemias and this has stimulated early trials to evaluate novel agents which target the dysregulated apoptotic pathways characteristic of this disease. © 2010 Blackwell Publishing Ltd.

  11. Characterizing granular networks using topological metrics

    Dijksman, Joshua A.; Kovalcinova, Lenka; Ren, Jie; Behringer, Robert P.; Kramar, Miroslav; Mischaikow, Konstantin; Kondic, Lou

    2018-04-01

    We carry out a direct comparison of experimental and numerical realizations of the exact same granular system as it undergoes shear jamming. We adjust the numerical methods used to optimally represent the experimental settings and outcomes up to microscopic contact force dynamics. Measures presented here range from microscopic through mesoscopic to systemwide characteristics of the system. Topological properties of the mesoscopic force networks provide a key link between microscales and macroscales. We report two main findings: (1) The number of particles in the packing that have at least two contacts is a good predictor for the mechanical state of the system, regardless of strain history and packing density. All measures explored in both experiments and numerics, including stress-tensor-derived measures and contact numbers depend in a universal manner on the fraction of nonrattler particles, fNR. (2) The force network topology also tends to show this universality, yet the shape of the master curve depends much more on the details of the numerical simulations. In particular we show that adding force noise to the numerical data set can significantly alter the topological features in the data. We conclude that both fNR and topological metrics are useful measures to consider when quantifying the state of a granular system.

  12. Collisional model for granular impact dynamics.

    Clark, Abram H; Petersen, Alec J; Behringer, Robert P

    2014-01-01

    When an intruder strikes a granular material from above, the grains exert a stopping force which decelerates and stops the intruder. Many previous studies have used a macroscopic force law, including a drag force which is quadratic in velocity, to characterize the decelerating force on the intruder. However, the microscopic origins of the force-law terms are still a subject of debate. Here, drawing from previous experiments with photoelastic particles, we present a model which describes the velocity-squared force in terms of repeated collisions with clusters of grains. From our high speed photoelastic data, we infer that "clusters" correspond to segments of the strong force network that are excited by the advancing intruder. The model predicts a scaling relation for the velocity-squared drag force that accounts for the intruder shape. Additionally, we show that the collisional model predicts an instability to rotations, which depends on the intruder shape. To test this model, we perform a comprehensive experimental study of the dynamics of two-dimensional granular impacts on beds of photoelastic disks, with different profiles for the leading edge of the intruder. We particularly focus on a simple and useful case for testing shape effects by using triangular-nosed intruders. We show that the collisional model effectively captures the dynamics of intruder deceleration and rotation; i.e., these two dynamical effects can be described as two different manifestations of the same grain-scale physical processes.

  13. A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

    Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys

    2015-04-01

    We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the

  14. Effects of Cinnamon Extract on Cerebellum Histomorphometry in Diabetic Rats’ Fetus

    AR Rafati

    2013-10-01

    Full Text Available Abstract Background & aim: In pregnant women, maternal diabetes occurs when the pancreas does not produce enough insulin, so glucose increases in the mother's blood and the blood of the fetus therefore causing many complications in children. The aim of this study was to evaluate the effects of cinnamon on morphometric histologic changes on fetal cerebellum of diabetic rats at days 18 and 20. Methods: In this study, 32 healthy female Wistar rats were prepared and randomly divided into four groups, normal control, diabetic, healthy subjects treated with cinnamon and cinnamon extract-treated diabetic groups. Diabetic groups were subjected by intraperitoneal of streptozotocin. All groups were charged with natural mating and they received a dose of 60 mg/ kg of cinnamon at the first day off pregnancy. After formation of the nervous system, in the eighteenth and twentieth day of pregnancy, the mother of the four mice were anesthetized and the fetus was removed for sampling. The histological slides were prepared and various parameters were studied in the cerebellum. Data were analyzed using one-way ANOVA and Duncan test. Results: The thickness of gray matter, and the gray matter white cells in the cerebellum of diabetic rats compared to other groups tested at days of18 and 20 and embryonic cells in the white matter of the cerebellum at day 18 was significantly decreased (p< 0.05. Conclusion: Administration of cinnamon extract reduces mothers’ blood sugar levels therefore preventing the complications of diabetes on the fetal cerebellum. Key words: cinnamon extract, Diabetes, cerebellum, Rat.

  15. CD44-positive cells are candidates for astrocyte precursor cells in developing mouse cerebellum.

    Cai, Na; Kurachi, Masashi; Shibasaki, Koji; Okano-Uchida, Takayuki; Ishizaki, Yasuki

    2012-03-01

    Neural stem cells are generally considered to be committed to becoming precursor cells before terminally differentiating into either neurons or glial cells during neural development. Neuronal and oligodendrocyte precursor cells have been identified in several areas in the murine central nervous system. The presence of astrocyte precursor cells (APCs) is not so well understood. The present study provides several lines of evidence that CD44-positive cells are APCs in the early postnatal mouse cerebellum. In developing mouse cerebellum, CD44-positive cells, mostly located in the white matter, were positive for the markers of the astrocyte lineage, but negative for the markers of mature astrocytes. CD44-positive cells were purified from postnatal cerebellum by fluorescence-activated cell sorting and characterized in vitro. In the absence of any signaling molecule, many cells died by apoptosis. The surviving cells gradually expressed glial fibrillary acidic protein, a marker for mature astrocytes, indicating that differentiation into mature astrocytes is the default program for these cells. The cells produced no neurospheres nor neurons nor oligodendrocytes under any condition examined, indicating these cells are not neural stem cells. Leukemia inhibitory factor greatly promoted astrocytic differentiation of CD44-positive cells, whereas bone morphogenetic protein 4 (BMP4) did not. Fibroblast growth factor-2 was a potent mitogen for these cells, but was insufficient for survival. BMP4 inhibited activation of caspase-3 and greatly promoted survival, suggesting a novel role for BMP4 in the control of development of astrocytes in cerebellum. We isolated and characterized only CD44 strongly positive large cells and discarded small and/or CD44 weakly positive cells in this study. Further studies are necessary to characterize these cells to help determine whether CD44 is a selective and specific marker for APCs in the developing mouse cerebellum. In conclusion, we succeeded in

  16. An intact action-perception coupling depends on the integrity of the cerebellum.

    Christensen, Andrea; Giese, Martin A; Sultan, Fahad; Mueller, Oliver M; Goericke, Sophia L; Ilg, Winfried; Timmann, Dagmar

    2014-05-07

    It is widely accepted that action and perception in humans functionally interact on multiple levels. Moreover, areas originally suggested to be predominantly motor-related, as the cerebellum, are also involved in action observation. However, as yet, few studies provided unequivocal evidence that the cerebellum is involved in the action perception coupling (APC), specifically in the integration of motor and multisensory information for perception. We addressed this question studying patients with focal cerebellar lesions in a virtual-reality paradigm measuring the effect of action execution on action perception presenting self-generated movements as point lights. We measured the visual sensitivity to the point light stimuli based on signal detection theory. Compared with healthy controls cerebellar patients showed no beneficial influence of action execution on perception indicating deficits in APC. Applying lesion symptom mapping, we identified distinct areas in the dentate nucleus and the lateral cerebellum of both hemispheres that are causally involved in APC. Lesions of the right ventral dentate, the ipsilateral motor representations (lobules V/VI), and most interestingly the contralateral posterior cerebellum (lobule VII) impede the benefits of motor execution on perception. We conclude that the cerebellum establishes time-dependent multisensory representations on different levels, relevant for motor control as well as supporting action perception. Ipsilateral cerebellar motor representations are thought to support the somatosensory state estimate of ongoing movements, whereas the ventral dentate and the contralateral posterior cerebellum likely support sensorimotor integration in the cerebellar-parietal loops. Both the correct somatosensory as well as the multisensory state representations are vital for an intact APC.

  17. Review and outlook: from single nanoparticles to self-assembled monolayers and granular GMR sensors

    Alexander Weddemann

    2010-11-01

    Full Text Available This paper highlights recent advances in synthesis, self-assembly and sensing applications of monodisperse magnetic Co and Co-alloyed nanoparticles. A brief introduction to solution phase synthesis techniques as well as the magnetic properties and aspects of the self-assembly process of nanoparticles will be given with the emphasis placed on selected applications, before recent developments of particles in sensor devices are outlined. Here, the paper focuses on the fabrication of granular magnetoresistive sensors by the employment of particles themselves as sensing layers. The role of interparticle interactions is discussed.

  18. Fast spot-based multiscale simulations of granular drainage

    Rycroft, Chris H.; Wong, Yee Lok; Bazant, Martin Z.

    2009-05-22

    We develop a multiscale simulation method for dense granular drainage, based on the recently proposed spot model, where the particle packing flows by local collective displacements in response to diffusing"spots'" of interstitial free volume. By comparing with discrete-element method (DEM) simulations of 55,000 spheres in a rectangular silo, we show that the spot simulation is able to approximately capture many features of drainage, such as packing statistics, particle mixing, and flow profiles. The spot simulation runs two to three orders of magnitude faster than DEM, making it an appropriate method for real-time control or optimization. We demonstrateextensions for modeling particle heaping and avalanching at the free surface, and for simulating the boundary layers of slower flow near walls. We show that the spot simulations are robust and flexible, by demonstrating that they can be used in both event-driven and fixed timestep approaches, and showing that the elastic relaxation step used in the model can be applied much less frequently and still create good results.

  19. Controlling wave propagation through nonlinear engineered granular systems

    Leonard, Andrea

    We study the fundamental dynamic behavior of a special class of ordered granular systems in order to design new, structured materials with unique physical properties. The dynamic properties of granular systems are dictated by the nonlinear, Hertzian, potential in compression and zero tensile strength resulting from the discrete material structure. Engineering the underlying particle arrangement of granular systems allows for unique dynamic properties, not observed in natural, disordered granular media. While extensive studies on 1D granular crystals have suggested their usefulness for a variety of engineering applications, considerably less attention has been given to higher-dimensional systems. The extension of these studies in higher dimensions could enable the discovery of richer physical phenomena not possible in 1D, such as spatial redirection and anisotropic energy trapping. We present experiments, numerical simulation (based on a discrete particle model), and in some cases theoretical predictions for several engineered granular systems, studying the effects of particle arrangement on the highly nonlinear transient wave propagation to develop means for controlling the wave propagation pathways. The first component of this thesis studies the stress wave propagation resulting from a localized impulsive loading for three different 2D particle lattice structures: square, centered square, and hexagonal granular crystals. By varying the lattice structure, we observe a wide range of properties for the propagating stress waves: quasi-1D solitary wave propagation, fully 2D wave propagation with tunable wave front shapes, and 2D pulsed wave propagation. Additionally the effects of weak disorder, inevitably present in real granular systems, are investigated. The second half of this thesis studies the solitary wave propagation through 2D and 3D ordered networks of granular chains, reducing the effective density compared to granular crystals by selectively placing wave

  20. Granular flow in a rotating drum: Experiments and theory

    Hung, C. Y.; Stark, C. P.; Capart, H.; Li, L.; Smith, B.; Grinspun, E.

    2015-12-01

    Erosion at the base of a debris flow fundamentally controls how large the flow will become and how far it will travel. Experimental observations of this important phenomenon are rather limited, and this lack has led theoretical treatments to making ad hoc assumptions about the basal process. In light of this, we carried out a combination of laboratory experiments and theoretical analysis of granular flow in a rotating drum, a canonical example of steady grain motion in which entrainment rates can be precisely controlled. Our main result is that basal sediment is entrained as the velocity profile adjusts to imbalance in the flow of kinetic energy.Our experimental apparatus consisted of a 40cm-diameter drum, 4cm-deep, half-filled with 2.3mm grains. Rotation rates varied from 1-70 rpm. We varied the effective scale by varying effective gravity from 1g to 70g on a geotechnical centrifuge. The field of grain motion was recorded using high-speed video and mapped using particle tracking velocimetry. In tandem we developed a depth-averaged theory using balance equations for mass, momentum and kinetic energy. We assumed a linearized GDR Midi granular rheology [da Cruz, 2005] and a Coulomb friction law along the sidewalls [Jop et al., 2005]. A scaling analysis of our equations yields a dimensionless "entrainment number" En, which neatly parametrizes the flow geometry in the drum for a wide range of variables, e.g., rotation rate and effective gravity. At low En, the flow profile is planar and kinetic energy is balanced locally in the flow layer. At high En, the flow profile is sigmoidal (yin-yang shaped) and the kinetic energy is dominated by longitudinal, streamwise transfer. We observe different scaling behavior under each of these flow regimes, e.g., between En and kinetic energy, surface slope and flow depth. Our theory correctly predicts their scaling exponents and the value of En at which the regime transition takes place. We are also able to make corrections for

  1. Evaluation of interlayer ferromagnetic coupling for stacked media by adding reference layer

    Tham, K K; Saito, S; Itagaki, N; Hinata, S; Takahashi, M; Hasegawa, D

    2011-01-01

    The trial for quantitative evaluation of interlayer ferromagnetic coupling between granular and cap layer in stacked media is reported. The evaluation is realized by analyzing M-H loop of stacked media with another reference layer added on the cap layer. The reference layer is antiferromagnetically coupled with the cap layer through non-magnetic spacer layer. In this experiment, Rh which leads to antiferromagnetic coupling constant along film normal direction of around 2 erg/cm 2 was used as non-magnetic spacer layer. According to the evaluation result done by this method, when thickness of the spacer Pd layer between granular layer and cap layer is increased to 1.1 nm, ferromagnetic coupling constant is weakened to 7.2 erg/cm 2 which results in reduction of saturation field.

  2. Theta synchronization between medial prefrontal cortex and cerebellum is associated with adaptive performance of associative learning behavior

    Chen, Hao; Wang, Yi-jie; Yang, Li; Sui, Jian-feng; Hu, Zhi-an; Hu, Bo

    2016-01-01

    Associative learning is thought to require coordinated activities among distributed brain regions. For example, to direct behavior appropriately, the medial prefrontal cortex (mPFC) must encode and maintain sensory information and then interact with the cerebellum during trace eyeblink conditioning (TEBC), a commonly-used associative learning model. However, the mechanisms by which these two distant areas interact remain elusive. By simultaneously recording local field potential (LFP) signals from the mPFC and the cerebellum in guinea pigs undergoing TEBC, we found that theta-frequency (5.0–12.0 Hz) oscillations in the mPFC and the cerebellum became strongly synchronized following presentation of auditory conditioned stimulus. Intriguingly, the conditioned eyeblink response (CR) with adaptive timing occurred preferentially in the trials where mPFC-cerebellum theta coherence was stronger. Moreover, both the mPFC-cerebellum theta coherence and the adaptive CR performance were impaired after the disruption of endogenous orexins in the cerebellum. Finally, association of the mPFC -cerebellum theta coherence with adaptive CR performance was time-limited occurring in the early stage of associative learning. These findings suggest that the mPFC and the cerebellum may act together to contribute to the adaptive performance of associative learning behavior by means of theta synchronization. PMID:26879632

  3. On the submerging of a spherical intruder into granular beds

    Wu Chuan-Yu

    2017-01-01

    Full Text Available Granular materials are complex systems and their mechanical behaviours are determined by the material properties of individual particles, the interaction between particles and the surrounding media, which are still incompletely understood. Using an advanced discrete element method (DEM, we simulate the submerging process of a spherical projectile (an intruder into granular materials of various properties with a zero penetration velocity (i.e. the intruder is touching the top surface of the granular bed and released from stationary and examine its settling behaviour. By systematically changing the density and size of the intruder and the particle density (i.e. the density of the particles in the granular bed, we find that the intruder can sink deep into the granular bed even with a zero penetration velocity. Furthermore, we confirm that under certain conditions the granular bed can behave like a Newtonian liquid and the submerging intruder can reach a constant velocity, i.e. the terminal velocity, identical to the settling of a sphere in a liquid, as observed experimentally. A mathematical model is also developed to predict the maximum penetration depth of the intruder. The model predictions are compared with experimental data reported in the literature,good agreement was obtained, demonstrating the model can accurately predict the submerging behaviour of the intruder in the granular media.

  4. Consideration of reinforcement mechanism in the short fiber mixing granular materials by granular element simulations

    Mori, Kentaro; Kaneko, Kenji; Hashizume, Yutaka

    2017-06-01

    The short fiber mixing method is well known as one of the method to improve the strength of gran- ular soils in geotechnical engineering. Mechanical properties of the short fiber mixing granular materials are influenced by many factors, such as the mixture ratio of the short fiber, the material of short fiber, the length, and the orientation. In particular, the mixture ratio of the short fibers is very important in mixture design. In the past study, we understood that the strength is reduced by too much short fiber mixing by a series of tri-axial compression experiments. Namely, there is "optimum mixture ratio" in the short fiber mixing granular soils. In this study, to consider the mechanism of occurrence of the optimum mixture ratio, we carried out the numerical experiments by granular element method. As the results, we can understand that the strength decrease when too much grain-fiber contact points exist, because a friction coefficient is smaller than the grain-grain contact points.

  5. Information granularity, big data, and computational intelligence

    Chen, Shyi-Ming

    2015-01-01

    The recent pursuits emerging in the realm of big data processing, interpretation, collection and organization have emerged in numerous sectors including business, industry, and government organizations. Data sets such as customer transactions for a mega-retailer, weather monitoring, intelligence gathering, quickly outpace the capacities of traditional techniques and tools of data analysis. The 3V (volume, variability and velocity) challenges led to the emergence of new techniques and tools in data visualization, acquisition, and serialization. Soft Computing being regarded as a plethora of technologies of fuzzy sets (or Granular Computing), neurocomputing and evolutionary optimization brings forward a number of unique features that might be instrumental to the development of concepts and algorithms to deal with big data. This carefully edited volume provides the reader with an updated, in-depth material on the emerging principles, conceptual underpinnings, algorithms and practice of Computational Intelligenc...

  6. Multiple impacts in dissipative granular chains

    Nguyen, Ngoc Son

    2014-01-01

    The extension of collision models for single impacts between two bodies, to the case of multiple impacts (which take place when several collisions occur at the same time in a multibody system) is a challenge in Solid Mechanics, due to the complexity of such phenomena, even in the frictionless case. This monograph aims at presenting the main multiple collision rules proposed in the literature. Such collisions typically occur in granular materials, the simplest of which are made of chains of aligned balls. These chains are used throughout the book to analyze various multiple impact rules which extend the classical Newton (kinematic restitution), Poisson (kinetic restitution) and Darboux-Keller (energetic or kinetic restitution) approaches for impact modelling. The shock dynamics in various types of chains of aligned balls (monodisperse, tapered, decorated, stepped chains) is carefully studied and shown to depend on several parameters: restitution coefficients, contact stiffness ratios, elasticity coefficients (...

  7. Fuzzy batch controller for granular materials

    Zamyatin Nikolaj

    2018-01-01

    Full Text Available The paper focuses on batch control of granular materials in production of building materials from fluorine anhydrite. Batching equipment is intended for smooth operation and timely feeding of supply hoppers at a required level. Level sensors and a controller of an asynchronous screw drive motor are used to control filling of the hopper with industrial anhydrite binders. The controller generates a required frequency and ensures required productivity of a feed conveyor. Mamdani-type fuzzy inference is proposed for controlling the speed of the screw that feeds mixture components. As related to production of building materials based on fluoride anhydrite, this method is used for the first time. A fuzzy controller is proven to be effective in controlling the filling level of the supply hopper. In addition, the authors determined optimal parameters of the batching process to ensure smooth operation and production of fluorine anhydrite materials of specified properties that can compete with gypsum-based products.

  8. Capturing gas in soft granular media

    MacMinn, Chris; Lee, Jeremy; Xu, Feng; Lee, Sungyon

    2017-11-01

    Bubble migration through soft granular materials involves a strong coupling between the bubble dynamics and the deformation of the material. This process is relevant to a variety of natural and industrial systems, from fluidized-bed reactors to the migration and venting of biogenic gas in sediments. Here, we study this process experimentally by injecting air into a quasi-2D, liquid-saturated packing of soft particles and measuring the morphology of the bubbles as they invade and then rise due to buoyancy. By systematically varying the confining stress, we show that the competition between buoyancy, capillarity, and elasticity leads to complex bubble-migration dynamics that transition from fluidization to pathway opening to pore invasion, with a strong and surprising impact on the amount of air trapped in the system. The authors are grateful for support from the Royal Society (IE150885), the John Fell Oxford University Press Research Fund, and the Maurice Lubbock Memorial Fund.

  9. Defining and testing a granular continuum element

    Rycroft, Chris H.; Kamrin, Ken; Bazant, Martin Z.

    2007-12-03

    Continuum mechanics relies on the fundamental notion of amesoscopic volume "element" in which properties averaged over discreteparticles obey deterministic relationships. Recent work on granularmaterials suggests a continuum law may be inapplicable, revealinginhomogeneities at the particle level, such as force chains and slow cagebreaking. Here, we analyze large-scale Discrete-Element Method (DEM)simulations of different granular flows and show that a "granularelement" can indeed be defined at the scale of dynamical correlations,roughly three to five particle diameters. Its rheology is rather subtle,combining liquid-like dependence on deformation rate and solid-likedependence on strain. Our results confirm some aspects of classicalplasticity theory (e.g., coaxiality of stress and deformation rate),while contradicting others (i.e., incipient yield), and can guide thedevelopment of more realistic continuum models.

  10. Particle filtration in consolidated granular systems

    Schwartz, L.M.; Wilkinson, D.J.; Bolsterli, M.; Hammond, P.

    1993-01-01

    Grain-packing algorithms are used to model the mechanical trapping of dilute suspensions of particles by consolidated granular media. We study the distribution of filtrate particles, the formation of a damage zone (internal filter cake), and the transport properties of the host--filter-cake composite. At the early stages of filtration, our simulations suggest simple relationships between the structure of the internal filter cake and the characteristics of the underlying host matrix. These relationships are then used to describe the dynamics of the filtration process. Depending on the grain size and porosity of the host matrix, calculated filtration rates may either be greater than (spurt loss) or less than (due to internal clogging) those predicted by standard surface-filtration models

  11. Transient response in granular bounded heap flows

    Xiao, Hongyi; Ottino, Julio M.; Lueptow, Richard M.; Umbanhowar, Paul B.

    2017-11-01

    Heap formation, a canonical granular flow, is common in industry and is also found in nature. Here, we study the transition between steady flow states in quasi-2D bounded heaps by suddenly changing the feed rate from one fixed value to another. During the transition, in both experiments and discrete element method simulations, an additional wedge of flowing particles propagates over the rising free surface. The downstream edge of the wedge - the wedge front - moves downstream with velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The transient flux profile during the entire transition is well modeled by a diffusion-like equation derived from local mass balance and a local linear relation between the flux and the surface slope. Scalings for the transient kinematics during the flow transitions are developed based on the flux profiles. Funded by NSF Grant CBET-1511450.

  12. Granular Segregation by an Oscillating Ratchet Mechanism

    Igarashi, A.; Horiuchi, Ch.

    2004-01-01

    We report on a method to segregate granular mixtures which consist of two kinds of particles by an oscillating ''ratchet'' mechanism. The segregation system has an asymmetrical sawtooth-shaped base which is vertically oscillating. Such a ratchet base produces a directional current of particles owing to its transport property. It is a counterintuitive and interesting phenomenon that a vertically vibrated base transports particles horizontally. This system is studied with numerical simulations, and it is found that we can apply such a system to segregation of mixtures of particles with different properties (radius or mass). Furthermore, we find out that an appropriate inclination of the ratchet-base makes the quality of segregation high. (author)

  13. Solitary Wave Interactions in Granular Media

    WEN Zhen-Ying; WANG Shun-Jin; ZHANG Xiu-Ming; LI Lei

    2007-01-01

    We numerically study the interactions of solitary waves in granular media, by considering a chain of beads, which repel upon contact via the Hertz-type potential, V ∝δn, with 5/2 ≤n≤3 and δ≥0,δbeing the bead-bead overlap. There are two collision types of solitary waves, overtaking collision and head-on collision, in the chain of beads. Our quantitative results show that after collision the large solitary wave gains energy and the small one loses energy for overtaking type while the large one loses energy, and the small one gains energy for head-on type. The scattering effects decrease with n for overtaking collision whereas increase with n for head-on collision.

  14. Two methods to measure granular gas temperature

    Chastaing, J.-Y.; Géminard, J.-C.; Naert, A.

    2017-07-01

    Grains are vibrated so as to achieve a granular gas, here regarded as an archetype of a dissipative non equilibrium steady state (NESS). We report on two distinct and concordant experimental measures of the system effective temperature. To do so, a blade fastened to the shaft of a small DC-motor, immersed in the grains, behaves as a driven 1D Brownian rotator, which is used as both actuator and sensor simultaneously. On the one hand, the Gallavotti-Cohen fluctuation theorem, which involves a measure of the asymmetry of the energy exchanges between the rotator and the NESS reservoir, provides a first effective temperature. On the other hand, the fluctuation-dissipation theorem, which involves the relation between the spontaneous fluctuations and the response to a weak perturbation, defines a second, independent, effective temperature. Both methods, even though they are based on drastically different ideas, give nicely concordant results.

  15. Thermal energy storage in granular deposits

    Ratuszny, Paweł

    2017-10-01

    Energy storage technology is crucial for the development of the use of renewable energy sources. This is a substantial constraint, however it can, to some extent, be solved by storing energy in its various forms: electrical, mechanical, chemical and thermal. This article presents the results of research in thermal properties of granular deposits. Correlation between temperature changes in the stores over a period of time and their physical properties has been studied. The results of the research have practical application in designing thermal stores based on bulk materials and ground deposits. Furthermore, the research results are significant for regeneration of the lower ground sources for heat pumps and provide data for designing ground heat exchangers for ventilation systems.

  16. Frictional granular mechanics: A variational approach

    Holtzman, R.; Silin, D.B.; Patzek, T.W.

    2009-10-16

    The mechanical properties of a cohesionless granular material are evaluated from grain-scale simulations. Intergranular interactions, including friction and sliding, are modeled by a set of contact rules based on the theories of Hertz, Mindlin, and Deresiewicz. A computer generated, three-dimensional, irregular pack of spherical grains is loaded by incremental displacement of its boundaries. Deformation is described by a sequence of static equilibrium configurations of the pack. A variational approach is employed to find the equilibrium configurations by minimizing the total work against the intergranular loads. Effective elastic moduli are evaluated from the intergranular forces and the deformation of the pack. Good agreement between the computed and measured moduli, achieved with no adjustment of material parameters, establishes the physical soundness of the proposed model.

  17. Sorption of metaldehyde using granular activated carbon

    S. Salvestrini

    2017-09-01

    Full Text Available In this work, the ability of granular activated carbon (GAC to sorb metaldehyde was evaluated. The kinetic data could be described by an intra-particle diffusion model, which indicated that the porosity of the sorbent strongly influenced the rate of sorption. The analysis of the equilibrium sorption data revealed that ionic strength and temperature did not play any significant role in the metaldehyde uptake. The sorption isotherms were successfully predicted by the Freundlich model. The GAC used in this paper exhibited a higher affinity and sorption capacity for metaldehyde with respect to other GACs studied in previous works, probably as a result of its higher specific surface area and high point of zero charge.

  18. NMRI Measurements of Flow of Granular Mixtures

    Nakagawa, Masami; Waggoner, R. Allen; Fukushima, Eiichi

    1996-01-01

    We investigate complex 3D behavior of granular mixtures in shaking and shearing devices. NMRI can non-invasively measure concentration, velocity, and velocity fluctuations of flows of suitable particles. We investigate origins of wall-shear induced convection flow of single component particles by measuring the flow and fluctuating motion of particles near rough boundaries. We also investigate if a mixture of different size particles segregate into their own species under the influence of external shaking and shearing disturbances. These non-invasive measurements will reveal true nature of convecting flow properties and wall disturbance. For experiments in a reduced gravity environment, we will design a light weight NMR imager. The proof of principle development will prepare for the construction of a complete spaceborne system to perform experiments in space.

  19. Pneumatic fractures in Confined Granular Media

    Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik; Turkaya, Semih

    2016-04-01

    We will present our ongoing study of the patterns formed when air flows into a dry, non-cohesive porous medium confined in a horizontal Hele-Shaw cell. This is an optically transparent system consisting of two glass plates separated by 0.5 to 1 mm, containing a packing of dry 80 micron beads in between. The cell is rectangular and has an air-permeable boundary (blocking beads) at one short edge, while the other three edges are completely sealed. The granular medium is loosely packed against the semi-permeable boundary and fills about 80 % of the cell volume. This leaves an empty region at the sealed side, where an inlet allows us to set and maintain the air at a constant overpressure (0.1 - 2 bar). For the air trapped inside the cell to relax its overpressure it has to move through the deformable granular medium. Depending on the applied overpressure and initial density of the medium, we observe a range of different behaviors such as seepage through the pore-network with or without an initial compaction of the solid, formation of low density bubbles with rearrangement of particles, granular fingering/fracturing, and erosion inside formed channels/fractures. The experiments are recorded with a high-speed camera at a framerate of 1000 images/s and a resolution of 1024x1024 pixels. We use various image processing techniques to characterize the evolution of the air invasion patterns and the deformations in the surrounding material. The experiments are similar to deformation processes in porous media which are driven by pore fluid overpressure, such as mud volcanoes and hydraulic or pneumatic (gas-induced) fracturing, and the motivation is to increase the understanding of such processes by optical observations. In addition, this setup is an experimental version of the numerical models analyzed by Niebling et al. [1,2], and is useful for comparison with their results. In a directly related project [3], acoustic emissions from the cell plate are recorded during

  20. Unjamming a granular hopper by vibration

    Janda, A.; Maza, D.; Garcimartín, A.; Kolb, E.; Lanuza, J.; Clément, E.

    2009-07-01

    We present an experimental study of the outflow of a hopper continuously vibrated by a piezoelectric device. Outpouring of grains can be achieved for apertures much below the usual jamming limit observed for non-vibrated hoppers. Granular flow persists down to the physical limit of one grain diameter, a limit reached for a finite vibration amplitude. For the smaller orifices, we observe an intermittent regime characterized by alternated periods of flow and blockage. Vibrations do not significantly modify the flow rates both in the continuous and the intermittent regime. The analysis of the statistical features of the flowing regime shows that the flow time significantly increases with the vibration amplitude. However, at low vibration amplitude and small orifice sizes, the jamming time distribution displays an anomalous statistics.

  1. Viscoinertial regime of immersed granular flows

    Amarsid, L.; Delenne, J.-Y.; Mutabaruka, P.; Monerie, Y.; Perales, F.; Radjai, F.

    2017-07-01

    By means of extensive coupled molecular dynamics-lattice Boltzmann simulations, accounting for grain dynamics and subparticle resolution of the fluid phase, we analyze steady inertial granular flows sheared by a viscous fluid. We show that, for a broad range of system parameters (shear rate, confining stress, fluid viscosity, and relative fluid-grain density), the frictional strength and packing fraction can be described by a modified inertial number incorporating the fluid effect. In a dual viscous description, the effective viscosity diverges as the inverse square of the difference between the packing fraction and its jamming value, as observed in experiments. We also find that the fabric and force anisotropies extracted from the contact network are well described by the modified inertial number, thus providing clear evidence for the role of these key structural parameters in dense suspensions.

  2. Hyperstaticity and loops in frictional granular packings

    Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.

    2009-06-01

    The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.

  3. Steady state of tapped granular polygons

    Carlevaro, Carlos M; Pugnaloni, Luis A

    2011-01-01

    The steady state packing fraction of a tapped granular bed is studied for different grain shapes via a discrete element method. Grains are monosized regular polygons, from triangles to icosagons. Comparisons with disc packings show that the steady state packing fraction as a function of the tapping intensity presents the same general trends in polygon packings. However, better packing fractions are obtained, as expected, for shapes that can tessellate the plane (triangles, squares and hexagons). In addition, we find a sharp transition for packings of polygons with more than 13 vertices signaled by a discontinuity in the packing fraction at a particular tapping intensity. Density fluctuations for most shapes are consistent with recent experimental findings in disc packing; however, a peculiar behavior is found for triangles and squares

  4. Experimental observations of granular debris flows

    Ghilardi, P.

    2003-04-01

    Various tests are run using two different laboratory flumes with rectangular cross section and transparent walls. The grains used in a single experiment have an almost constant grain sizes; mean diameter ranges from 5 mm to 20 mm. In each test various measurements are taken: hydrograms, velocity distribution near the transparent walls and on the free surface, average flow concentration. Concentration values are measured taking samples. Velocity distributions are obtained from movies recorded by high speed video cameras capable of 350 frames per second; flow rates and depth hydrograms are computed from the same velocity distributions. A gate is installed at the beginning of one of the flumes; this gate slides normally to the bed and opens very quickly, reproducing a dam-break. Several tests are run using this device, varying channel slope, sediment concentration, initial mixture thickness before the gate. Velocity distribution in the flume is almost constant from left to right, except for the flow sections near the front. The observed discharges and velocities are less than those given by a classic dam break formula, and depend on sediment concentration. The other flume is fed by a mixture with constant discharge and concentration, and is mainly used for measuring velocity distributions when the flow is uniform, with both rigid and granular bed, and to study erosion/deposition processes near debris flow dams or other mitigation devices. The equilibrium slope of the granular bed is very close to that given by the classical equilibrium formulas for debris flow. Different deposition processes are observed depending on mixture concentration and channel geometry.

  5. Respiratory Neuron Activity in the Mesencephalon, Diencephalon and Cerebellum of the Carp

    Ballintijn, C.M.; Luiten, P.G.M.; Jüch, P.J.W.

    1979-01-01

    The functional properties, localization and connections of neurons with a respiratory-rhythmic firing pattern in the mesencephalon, diencephalon and cerebellum of the carp were studied. Some neurons acquire respiratory rhythm only as a side effect of respiration via sensory stimulation by movements

  6. REPETITIVE TMS ON LEFT CEREBELLUM AFFECTS IMPULSIVITY IN BORDERLINE PERSONALITY DISORDER : A PILOT STUDY

    Giulia Zelda De Vidovich

    2016-12-01

    Full Text Available The borderline personality disorder (BPD is characterized by a severe pattern of instability in emotional regulation, interpersonal relationships, identity, and impulse control. These functions are related to the prefrontal cortex (PFC, and since PFC shows a rich anatomical connectivity with the cerebellum, the functionality of the cerebellar-PFC axis may impact on BPD. In this study we investigated the potential involvement of cerebello-thalamo-cortical connections in impulsive reactions through a pre/post stimulation design. BPD patients (n=8 and healthy controls (HC; n=9 performed an Affective Go/No-Go task (AGN assessing information processing biases for positive and negative stimuli before and after repetitive transcranial magnetic stimulation (rTMS; 1 Hz/10 min, 80% RMT over the left lateral cerebellum. The AGN task consisted of four blocks requiring associative capacities of increasing complexity. BPD patients performed significantly worse than the HC, especially when cognitive demands was high (3rd and 4th block, but their performace approached that of HC after rTMS (rTMS was almost ineffective in HC. The more evident effect of rTMS in complex associative tasks might have occurred since the cerebellum is deeply involved in integration and coordination of different stimuli. We hypothesize that, in BPD patients, cerebello-thalamo-cortical communication is altered, resulting in emotional dysregulation and disturbed impulse control. The rTMS over the left cerebellum might have interfered with existing functional connections exerting a facilitating effect on PFC control.

  7. Cerebellum segmentation in MRI using atlas registration and local multi-scale image descriptors

    van der Lijn, F.; de Bruijne, M.; Hoogendam, Y.Y.

    2009-01-01

    We propose a novel cerebellum segmentation method for MRI, based on a combination of statistical models of the structure's expected location in the brain and its local appearance. The appearance model is obtained from a k-nearest-neighbor classifier, which uses a set of multi-scale local image...

  8. Monitoring the native phosphorylation state of plasma membrane proteins from a single mouse cerebellum

    Schindler, J.; Ye, J. Y.; Jensen, Ole Nørregaard

    2013-01-01

    Neuronal processing in the cerebellum involves the phosphorylation and dephosphorylation of various plasma membrane proteins such as AMPA or NMDA receptors. Despite the importance of changes in phosphorylation pattern, no global phospho-proteome analysis has yet been performed. As plasma membrane...

  9. Information to cerebellum on spinal motor networks mediated by the dorsal spinocerebellar tract

    Stecina, Katinka; Fedirchuk, Brent; Hultborn, Hans

    2013-01-01

    of peripheral sensory input to the cerebellum in general, and during rhythmic movements such as locomotion and scratch. In contrast, the VSCT was seen as conveying a copy of the output of spinal neuronal circuitry, including those circuits generating rhythmic motor activity (the spinal central pattern generator...

  10. The anatomy of fear learning in the cerebellum : A systematic meta-analysis

    Lange, Iris; Kasanova, Zuzana; Goossens, Liesbet; Leibold, Nicole; De Zeeuw, Chris I; van Amelsvoort, Therese; Schruers, Koen

    2015-01-01

    Recent neuro-imaging studies have implicated the cerebellum in several higher-order functions. Its role in human fear conditioning has, however, received limited attention. The current meta-analysis examines the loci of cerebellar contributions to fear conditioning in healthy subjects, thus mapping,

  11. Localization and functional roles of corticotropin-releasing factor receptor type 2 in the cerebellum

    Gounko, Natalia V.; Gramsbergen, Albert; van der Want, Johannes J. L.

    The corticotropin-releasing factor (CRF) type 2 receptor has three splice variants alpha, beta, and gamma. In the rodent brain only CRF-R2 alpha is present. In the cerebellum, CRF-R2 alpha has two different isoforms: a full-length form (fl) and truncated (tr). Both forms CRF-R2 have a unique

  12. A single episode of neonatal seizures alters the cerebellum of immature rats

    Lomoio, S.; Necchi, D.; Mareš, Vladislav; Scherini, E.

    2011-01-01

    Roč. 93, č. 1 (2011), s. 17-24 ISSN 0920-1211 Institutional research plan: CEZ:AV0Z50110509 Keywords : metrazol seizures * cerebellum * Purkinje cells * GluR2/3 * GLT1 Subject RIV: FH - Neurology Impact factor: 2.290, year: 2011

  13. Deficient PKR in RAX/PKR Association Ameliorates Ethanol-Induced Neurotoxicity in the Developing Cerebellum.

    Li, Hui; Chen, Jian; Qi, Yuanlin; Dai, Lu; Zhang, Mingfang; Frank, Jacqueline A; Handshoe, Jonathan W; Cui, Jiajun; Xu, Wenhua; Chen, Gang

    2015-08-01

    Ethanol-induced neuronal loss is closely related to the pathogenesis of fetal alcohol spectrum disorders. The cerebellum is one of the brain areas that are most sensitive to ethanol. The mechanism underlying ethanol neurotoxicity remains unclear. Our previous in vitro studies have shown that the double-stranded RNA (dsRNA)-activated protein kinase (PKR) regulates neuronal apoptosis upon ethanol exposure and ethanol activates PKR through association with its intracellular activator RAX. However, the role of PKR and its interaction with RAX in vivo have not been investigated. In the current study, by utilizing N-PKR-/- mice, C57BL/6J mice with a deficient RAX-binding domain in PKR, we determined the critical role of RAX/PKR association in PKR-regulated ethanol neurotoxicity in the developing cerebellum. Our data indicate that while N-PKR-/- mice have a similar BAC profile as wild-type mice, ethanol induces less brain/body mass reduction as well as cerebellar neuronal loss. In addition, ethanol promotes interleukin-1β (IL-1β) secretion, and IL-1β is a master cytokine regulating inflammatory response. Importantly, ethanol-promoted IL-1β secretion is inhibited in the developing cerebellum of N-PKR-/- mice. Thus, RAX/PKR interaction and PKR activation regulate ethanol neurotoxicity in the developing cerebellum, which may involve ethanol-induced neuroinflammation. Further, PKR could be a possible target for pharmacological intervention to prevent or treat fetal alcohol spectrum disorder (FASD).

  14. Overexpression of mutant ataxin-3 in mouse cerebellum induces ataxia and cerebellar neuropathology.

    Nóbrega, Clévio; Nascimento-Ferreira, Isabel; Onofre, Isabel; Albuquerque, David; Conceição, Mariana; Déglon, Nicole; de Almeida, Luís Pereira

    2013-08-01

    Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is a fatal, dominant neurodegenerative disorder caused by the polyglutamine-expanded protein ataxin-3. Clinical manifestations include cerebellar ataxia and pyramidal signs culminating in severe neuronal degeneration. Currently, there is no therapy able to modify disease progression. In the present study, we aimed at investigating one of the most severely affected brain regions in the disorder--the cerebellum--and the behavioral defects associated with the neuropathology in this region. For this purpose, we injected lentiviral vectors encoding full-length human mutant ataxin-3 in the mouse cerebellum of 3-week-old C57/BL6 mice. We show that circumscribed expression of human mutant ataxin-3 in the cerebellum mediates within a short time frame--6 weeks, the development of a behavioral phenotype including reduced motor coordination, wide-based ataxic gait, and hyperactivity. Furthermore, the expression of mutant ataxin-3 resulted in the accumulation of intranuclear inclusions, neuropathological abnormalities, and neuronal death. These data show that lentiviral-based expression of mutant ataxin-3 in the mouse cerebellum induces localized neuropathology, which is sufficient to generate a behavioral ataxic phenotype. Moreover, this approach provides a physiologically relevant, cost-effective and time-effective animal model to gain further insights into the pathogenesis of MJD and for the evaluation of experimental therapeutics of MJD.

  15. The Cerebellum Generates Motor-to-Auditory Predictions: ERP Lesion Evidence

    Knolle, Franziska; Schroger, Erich; Baess, Pamela; Kotz, Sonja A.

    2012-01-01

    Forward predictions are crucial in motor action (e.g., catching a ball, or being tickled) but may also apply to sensory or cognitive processes (e.g., listening to distorted speech or to a foreign accent). According to the "internal forward model," the cerebellum generates predictions about somatosensory consequences of movements. These predictions…

  16. A case of illusory own-body perceptions after transcranial magnetic stimulation of the cerebellum

    Schutter, D.J.L.G.; Kammers, M.P.M.; Enter, D.; Honk, E.J. van

    2006-01-01

    Illusory own-body perceptions are 'body in space' misinterpretations of the brain and belong to the class of out-of-body experiences wherein the angular gyrus seems importantly implicated. In the present study additional cerebellum involvement in illusory own-body perceptions was investigated in a

  17. The cerebellum in Alzheimer's disease: evaluating its role in cognitive decline.

    Jacobs, Heidi I L; Hopkins, David A; Mayrhofer, Helen C; Bruner, Emiliano; van Leeuwen, Fred W; Raaijmakers, Wijnand; Schmahmann, Jeremy D

    2018-01-01

    The cerebellum has long been regarded as essential only for the coordination of voluntary motor activity and motor learning. Anatomical, clinical and neuroimaging studies have led to a paradigm shift in the understanding of the cerebellar role in nervous system function, demonstrating that the cerebellum appears integral also to the modulation of cognition and emotion. The search to understand the cerebellar contribution to cognitive processing has increased interest in exploring the role of the cerebellum in neurodegenerative and neuropsychiatric disorders. Principal among these is Alzheimer's disease. Here we review an already sizeable existing literature on the neuropathological, structural and functional neuroimaging studies of the cerebellum in Alzheimer's disease. We consider these observations in the light of the cognitive deficits that characterize Alzheimer's disease and in so doing we introduce a new perspective on its pathophysiology and manifestations. We propose an integrative hypothesis that there is a cerebellar contribution to the cognitive and neuropsychiatric deficits in Alzheimer's disease. We draw on the dysmetria of thought theory to suggest that this cerebellar component manifests as deficits in modulation of the neurobehavioural deficits. We provide suggestions for future studies to investigate this hypothesis and, ultimately, to establish a comprehensive, causal clinicopathological disease model. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Gating of Long-Term Potentiation by Nicotinic Acetylcholine Receptors at the Cerebellum Input Stage

    F. Prestori (Francesca); C. Bonardi (Claudia); L. Mapelli (Lisa); P. Lombardo (Paola); R. Goselink (Rianne); M.E. de Stefano (Maria Egle); D. Gandolfi (Daniela); J. Mapelli (Jonathan); D. Bertrand (Daniel); M. Schonewille (Martijn); C.I. de Zeeuw (Chris); E. D'Angelo (Egidio)

    2013-01-01

    textabstractThe brain needs mechanisms able to correlate plastic changes with local circuit activity and internal functional states. At the cerebellum input stage, uncontrolled induction of long-term potentiation or depression (LTP or LTD) between mossy fibres and granule cells can saturate synaptic

  19. The role of the cerebellum in the regulation of language functions.

    Starowicz-Filip, Anna; Chrobak, Adrian Andrzej; Moskała, Marek; Krzyżewski, Roger M; Kwinta, Borys; Kwiatkowski, Stanisław; Milczarek, Olga; Rajtar-Zembaty, Anna; Przewoźnik, Dorota

    2017-08-29

    The present paper is a review of studies on the role of the cerebellum in the regulation of language functions. This brain structure until recently associated chiefly with motor skills, visual-motor coordination and balance, proves to be significant also for cognitive functioning. With regard to language functions, studies show that the cerebellum determines verbal fluency (both semantic and formal) expressive and receptive grammar processing, the ability to identify and correct language mistakes, and writing skills. Cerebellar damage is a possible cause of aphasia or the cerebellar mutism syndrome (CMS). Decreased cerebellocortical connectivity as well as anomalies in the structure of the cerebellum are emphasized in numerous developmental dyslexia theories. The cerebellum is characterized by linguistic lateralization. From the neuroanatomical perspective, its right hemisphere and dentate nucleus, having multiple cerebellocortical connections with the cerebral cortical language areas, are particularly important for language functions. Usually, language deficits developed as a result of a cerebellar damage have subclinical intensity and require applying sensitive neuropsychological diagnostic tools designed to assess higher verbal functions.

  20. The role of the cerebellum in schizophrenia: from cognition to molecular pathways

    Peyman Yeganeh-Doost

    2011-01-01

    Full Text Available Beside its role in motor coordination, the cerebellum is involved in cognitive function such as attention, working memory, verbal learning, and sensory discrimination. In schizophrenia, a disturbed prefronto-thalamo-cerebellar circuit has been proposed to play a role in the pathophysiology. In addition, a deficit in the glutamatergic N-methyl-D-aspartate (NMDAf receptor has been hypothesized. The risk gene neuregulin 1 may play a major role in this process. We demonstrated a higher expression of the NMDA receptor subunit 2D in the right cerebellar regions of schizophrenia patients, which may be a secondary upregulation due to a dysfunctional receptor. In contrast, the neuregulin 1 risk variant containing at least one C-allele was associated with decreased expression of NMDA receptor subunit 2C, leading to a dysfunction of the NMDA receptor, which in turn may lead to a dysfunction of the gamma amino butyric acid (GABA system. Accordingly, from post-mortem studies, there is accumulating evidence that GABAergic signaling is decreased in the cerebellum of schizophrenia patients. As patients in these studies are treated with antipsychotics long term, we evaluated the effect of long-term haloperidol and clozapine treatment in an animal model. We showed that clozapine may be superior to haloperidol in restoring a deficit in NMDA receptor subunit 2C expression in the cerebellum. We discuss the molecular findings in the light of the role of the cerebellum in attention and cognitive deficits in schizophrenia.