29,463 research outputs found
A Novel Long-term, Multi-Channel and Non-invasive Electrophysiology Platform for Zebrafish.
Zebrafish are a popular vertebrate model for human neurological disorders and drug discovery. Although fecundity, breeding convenience, genetic homology and optical transparency have been key advantages, laborious and invasive procedures are required for electrophysiological studies. Using an electrode-integrated microfluidic system, here we demonstrate a novel multichannel electrophysiology unit to record multiple zebrafish. This platform allows spontaneous alignment of zebrafish and maintains, over days, close contact between head and multiple surface electrodes, enabling non-invasive long-term electroencephalographic recording. First, we demonstrate that electrographic seizure events, induced by pentylenetetrazole, can be reliably distinguished from eye or tail movement artifacts, and quantifiably identified with our unique algorithm. Second, we show long-term monitoring during epileptogenic progression in a scn1lab mutant recapitulating human Dravet syndrome. Third, we provide an example of cross-over pharmacology antiepileptic drug testing. Such promising features of this integrated microfluidic platform will greatly facilitate high-throughput drug screening and electrophysiological characterization of epileptic zebrafish
Micro Balloon Actuators for Aerodynamic Control
A robust, large-force, large-deflection micro balloon actuator for aerodynamic (manoeuvring) control of transonic aircraft has been developed. Using a novel process, high yield linear arrays of silicone balloons on a robust silicon substrate have been fabricated that can deflect vertically in excess of one mm. Balloon actuators have been tested under cyclic conditions to assess reliability. The actuators have been characterized in a wind tunnel to assess their suitability as aerodynamic control surfaces and flight-tested on a jet fighter to assess their resistance to varied temperatures and pressures at high velocity
A new approach for shaping of dual-reflector antennas
The shaping of 2-D dual-reflector antenna systems to generate a prescribed distribution with uniform phase at the aperture of the second reflector is examined. This method is based on the geometrical nature of Cassegrain and Gregorian dual-reflector antennas. The method of syntheses satisfies the principles of geometrical optics which are the foundations of dual-reflector designs. Instead of setting up differential equations or heuristically designing the subreflector, a set of algebraic equations is formulated and solved numerically to obtain the desired surfaces. The caustics of the reflected rays from the subreflector can be obtained and examined. Several examples of 2-D dual-reflector shaping are shown to validate the study. Geometrical optics and physical optics are used to calculate the scattered fields from the reflectors
SELF-DUAL ANYONS IN UNIFORM BACKGROUND FIELDS
We study relativistic self-dual Chern-Simons-Higgs systems in the presence of
uniform background fields that explicitly break CTP. A rich, but discrete
vacuum structure is found when the gauge symmetry is spontaneously broken,
while the symmetric phase can have an infinite vacuum degeneracy at tree level.
The latter is due to the proliferation of neutral solitonic states that cost
zero energy. Various novel self-dual solitons, such as these, are found in both
the symmetric and the asymmetric phases. Also by considering a similar system
on a two-sphere and the subsequent large sphere limit, we isolate sensible and
finite expressions for the conserved angular and linear momenta, which satisfy
anomalous commutation relations. We conclude with a few remarks on unresolved
issues.Comment: LaTeX, 20 pages, 4 uuencoded figures included
Bogomol'nyi equations for solitons in Maxwell-Chern-Simons gauge theories with the magnetic moment interaction term
Without assuming rotational invariance, we derive Bogomol'nyi equations for
the solitons in the abelian Chern-Simons gauge theories with the anomalous
magnetic moment interaction. We also evaluate the number of zero modes around a
static soliton configuration.Comment: 9 pages, Revtex, SNUTP-94/6
Higgs compositeness in gauge theories --- Resymplecticisation, scale setting and topology
As part of an ongoing programme to study gauge theories as
potential realisations of composite Higgs models, we consider the case of
on the lattice, both as a pure gauge theory, and with two
Dirac fermion flavors in the fundamental representation. In order to compare
results between these two cases and maintain control of lattice artefacts, we
make use of the gradient flow to set the scale of the simulations. We present
some technical aspects of the simulations, including preliminary results for
the scale setting in the two cases and results for the topological charge
history.Comment: 8 pages, 6 figures; talk presented at the 35th International
Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai
- …