1,739 research outputs found
THE RELATIONSHIP BETWEEN SHOULDER PAIN AND SCAPULAR MOBILITY IN TEENAGE BASEBALL PLAYERS
The purpose of this study was to identify the relationship between shoulder pain and scapular mobility for teenage baseball players. Thirty-five teenage baseball players (shoulder pain, n=11; healthy, n=24) were recruited in this study. The lateral scapula slide test (LSST), which represented as scapular mobility, was used to measure the scapular position and symmetry under varying loads. The result of this study showed that there was a difference in distance from the superior angle of the scapula to the spinous process of T2 between the two groups at shoulder 90?abduction
Event-driven simulations of a plastic, spiking neural network
We consider a fully-connected network of leaky integrate-and-fire neurons
with spike-timing-dependent plasticity. The plasticity is controlled by a
parameter representing the expected weight of a synapse between neurons that
are firing randomly with the same mean frequency. For low values of the
plasticity parameter, the activities of the system are dominated by noise,
while large values of the plasticity parameter lead to self-sustaining activity
in the network. We perform event-driven simulations on finite-size networks
with up to 128 neurons to find the stationary synaptic weight conformations for
different values of the plasticity parameter. In both the low and high activity
regimes, the synaptic weights are narrowly distributed around the plasticity
parameter value consistent with the predictions of mean-field theory. However,
the distribution broadens in the transition region between the two regimes,
representing emergent network structures. Using a pseudophysical approach for
visualization, we show that the emergent structures are of "path" or "hub"
type, observed at different values of the plasticity parameter in the
transition region.Comment: 9 pages, 6 figure
Anomalous Transport in Sketched Nanostructures at the LaAlO3/SrTiO3 Interface
The oxide heterostructure LaAlO3/SrTiO3 supports a two-dimensional electron
liquid with a variety of competing phases including magnetism,
superconductivity and weak antilocalization due to Rashba spin-orbit coupling.
Further confinement of this 2D electron liquid to the quasi-one-dimensional
regime can provide insight into the underlying physics of this system and
reveal new behavior. Here we describe magnetotransport experiments on narrow
LaAlO3/SrTiO3 structures created by a conductive atomic force microscope
lithography technique. Four-terminal local transport measurements on
~10-nm-wide Hall bar structures yield longitudinal resistances that are
comparable to the resistance quantum h/e2 and independent of the channel
length. Large nonlocal resistances (as large as 10^4 ohms) are observed in some
but not all structures with separations between current and voltage that are
large compared to the 2D mean-free path. The nonlocal transport is strongly
suppressed by the onset of superconductivity below ~200 mK. The origin of these
anomalous transport signatures is not understood, but may arise from coherent
transport defined by strong spin-orbit coupling and/or magnetic interactions
Analytic mode-matching for acoustic scattering in three dimensional waveguides with flexible walls: Application to a triangular duct
This is the post-print version of the Article. The official published version can be accessed from the links below - Copyright @ 2012 ElsevierAn analytic mode-matching method suitable for the solution of problems involving scattering in three-dimensional waveguides with flexible walls is presented. Prerequisite to the development of such methods is knowledge of closed form analytic expressions for the natural fluidâstructure coupled waveforms that propagate in each duct section and the corresponding orthogonality relations. In this article recent theory [J.B. Lawrie, Orthogonality relations for fluidâstructural waves in a 3-D rectangular duct with flexible walls, Proc. R. Soc. A. 465 (2009) 2347â2367] is extended to construct the non-separable eigenfunctions for acoustic propagation in a three-dimensional rectangular duct with four flexible walls. For the special case in which the duct cross-section is square, the symmetrical nature of the eigenfunctions enables the eigenmodes for a right-angled, isosceles triangular duct with flexible hypotenuse to be deduced. The partial orthogonality relation together with other important properties of the triangular modes are discussed. A mode-matching solution to the scattering of a fluidâstructure coupled wave at the junction of two identical semi-infinite ducts of triangular cross-section is demonstrated for two different sets of âjunctionâ conditions
"Water-cycle" mechanism for writing and erasing nanostructures at the LaAlO3/SrTiO3 interface
Nanoscale control of the metal-insulator transition in LaAlO3/ SrTiO3
heterostructures can be achieved using local voltages applied by a conductive
atomic-force microscope probe. One proposed mechanism for the writing and
erasing process involves an adsorbed H2O layer at the top LaAlO3 surface. In
this picture, water molecules dissociates into OH- and H+ which are then
selectively removed by a biased AFM probe. To test this mechanism, writing and
erasing experiments are performed in a vacuum AFM using various gas mixtures.
Writing ability is suppressed in those environments where H2O is not present.
The stability of written nanostructures is found to be strongly associated with
the ambient environment. The self-erasure process in air can be strongly
suppressed by creating a modest vacuum or replacing the humid air with dry
inert gas. These experiments provide strong constraints for theories of both
the writing process as well as the origin of interfacial conductance.Comment: 11 pages, 3 figure
Microarray studies on effects of Pneumocystis carinii infection on global gene expression in alveolar macrophages
<p>Abstract</p> <p>Background</p> <p><it>Pneumocystis </it>pneumonia is a common opportunistic disease in AIDS patients. The alveolar macrophage is an important effector cell in the clearance of <it>Pneumocystis </it>organisms by phagocytosis. However, both the number and phagocytic activity of alveolar macrophages are decreased in <it>Pneumocystis </it>infected hosts. To understand how <it>Pneumocystis </it>inactivates alveolar macrophages, Affymetrix GeneChip<sup>ÂŽ </sup>RG-U34A DNA microarrays were used to study the difference in global gene expression in alveolar macrophages from uninfected and <it>Pneumocystis carinii</it>-infected Sprague-Dawley rats.</p> <p>Results</p> <p>Analyses of genes that were affected by <it>Pneumocystis </it>infection showed that many functions in the cells were affected. Antigen presentation, cell-mediated immune response, humoral immune response, and inflammatory response were most severely affected, followed by cellular movement, immune cell trafficking, immunological disease, cell-to-cell signaling and interaction, cell death, organ injury and abnormality, cell signaling, infectious disease, small molecular biochemistry, antimicrobial response, and free radical scavenging. Since rats must be immunosuppressed in order to develop <it>Pneumocystis </it>infection, alveolar macrophages from four rats of the same sex and age that were treated with dexamethasone for the entire eight weeks of the study period were also examined. With a filter of false-discovery rate less than 0.1 and fold change greater than 1.5, 200 genes were found to be up-regulated, and 144 genes were down-regulated by dexamethasone treatment. During <it>Pneumocystis </it>pneumonia, 115 genes were found to be up- and 137 were down-regulated with the same filtering criteria. The top ten genes up-regulated by <it>Pneumocystis </it>infection were Cxcl10, Spp1, S100A9, Rsad2, S100A8, Nos2, RT1-Bb, Lcn2, RT1-Db1, and Srgn with fold changes ranging between 12.33 and 5.34; and the top ten down-regulated ones were Lgals1, Psat1, Tbc1d23, Gsta1, Car5b, Xrcc5, Pdlim1, Alcam, Cidea, and Pkib with fold changes ranging between -4.24 and -2.25.</p> <p>Conclusions</p> <p>In order to survive in the host, <it>Pneumocystis </it>organisms change the expression profile of alveolar macrophages. Results of this study revealed that <it>Pneumocystis </it>infection affects many cellular functions leading to reduced number and activity of alveolar macrophages during <it>Pneumocystis </it>pneumonia.</p
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Myricetin, the main flavonoid in Syzygium cumini leaf, is a novel inhibitor of platelet thiol isomerases PDI and ERp5
Background: Flavonoids have been characterized as a prominent class of compounds to treat thrombotic diseases through the inhibition of thiol isomerases. Syzygium cumini is a flavonoid-rich medicinal plant that contains myricetin and gallic acid. Little is known about the potential anti-platelet properties of S. cumini and its constituent flavonoids.
Objective
To evaluate the anti-platelet effects and mechanism of action of a polyphenol-rich extract (PESc) from S. cumini leaf and its most prevalent polyphenols, myricetin and gallic acid.
Methods
PESc, myricetin and gallic acid were incubated with platelet-rich plasma and washed platelets to assess platelet aggregation and activation. In vitro platelet adhesion and thrombus formation as well as in vivo bleeding time were performed. Finally, myricetin was incubated with recombinant thiol isomerases to assess its potential to bind and inhibit these, whilst molecular docking studies predicted possible binding sites.
Results:
PESc decreased platelet activation and aggregation induced by different agonists. Myricetin exerted potent anti-platelet effects, whereas gallic acid did not. Myricetin reduced the ability of platelets to spread on collagen, form thrombi in vitro without affecting haemostasis in vivo. Fluorescence quenching studies suggested myricetin binds to different thiol isomerases with similar affinity, despite inhibiting only protein disulphide isomerase (PDI) and ERp5 reductase activities (IC50~3.5 ÎźM). Finally, molecular docking studies suggested myricetin formed non-covalent bonds with PDI and ERp5.
Conclusions:
PESc and its most abundant flavonoid myricetin strongly inhibit platelet function. Additionally, myricetin is a novel inhibitor of ERp5 and PDI, unveiling a new therapeutic perspective for the treatment of thrombotic disorders
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