2,453 research outputs found
Second Set of Spaces
This document describes the Gloss infrastructure supporting implementation of
location-aware services. The document is in two parts. The first part describes
software architecture for the smart space. As described in D8, a local
architecture provides a framework for constructing Gloss applications, termed
assemblies, that run on individual physical nodes, whereas a global
architecture defines an overlay network for linking individual assemblies. The
second part outlines the hardware installation for local sensing. This
describes the first phase of the installation in Strathclyde University
Mechanism, localization and cure of atrial arrhythmias occurring after a new intraoperative endocardial radiofrequency ablation procedure for atrial fibrillation
AbstractOBJECTIVESThe purpose of this study was to test a new pattern of radiofrequency ablation for atrial fibrillation (AFib) intended to optimize atrial activation, and to demonstrate the usefulness of catheter techniques for mapping and ablation of postoperative atrial arrhythmias.BACKGROUNDLinear radiofrequency lesions have been used to cure AFib, but the optimal pattern of lesions is unknown and postoperative tachyarrhythmias are common.METHODSA radial pattern of linear radiofrequency lesions (Star) was made using an endocardial open surgical approach in 25 patients. Postoperative arrhythmias were induced and characterized during electrophysiological studies in 15 patients.RESULTSThe AFib was abolished in most patients (91%), but atrial flutter (AFlut) occurred in 96% of patients postoperatively. At postoperative electrophysiological studies, 37 flutter morphologies were studied in 15 patients (46% spontaneous, cycle length [CL] 223 ± 25 ms). Seven mechanisms (lesions discontinuity, n = 6; focal mechanism, n = 1) of AFlut were characterized in six patients. In these cases, flutter was abolished using further catheter radiofrequency ablation. In the remaining cases, flutter was usually localized to an area involving the interatrial septum, but no critical isthmus was identified for ablation. After 16 ± 10 months, 15 patients (65%) were asymptomatic with (n = 3) or without (n = 12) antiarrhythmic medications. Eight (35%) patients had persistent arrhythmias. Postoperative atrial electrical activation was near physiological.CONCLUSIONSThe AFib may be abolished using a radial pattern of linear endocardial radiofrequency lesions, but postoperative AFlut is common even when lesions are made under optimal conditions. Endocardial mapping techniques can be used to characterize the flutter mechanisms, thus enabling subsequent successful catheter ablation
High-Resolution Patterned Cellular Constructs by Droplet-Based 3D Printing.
Bioprinting is an emerging technique for the fabrication of living tissues that allows cells to be arranged in predetermined three-dimensional (3D) architectures. However, to date, there are limited examples of bioprinted constructs containing multiple cell types patterned at high-resolution. Here we present a low-cost process that employs 3D printing of aqueous droplets containing mammalian cells to produce robust, patterned constructs in oil, which were reproducibly transferred to culture medium. Human embryonic kidney (HEK) cells and ovine mesenchymal stem cells (oMSCs) were printed at tissue-relevant densities (10(7) cells mL(-1)) and a high droplet resolution of 1 nL. High-resolution 3D geometries were printed with features of ≤200 μm; these included an arborised cell junction, a diagonal-plane junction and an osteochondral interface. The printed cells showed high viability (90% on average) and HEK cells within the printed structures were shown to proliferate under culture conditions. Significantly, a five-week tissue engineering study demonstrated that printed oMSCs could be differentiated down the chondrogenic lineage to generate cartilage-like structures containing type II collagen
Models of the SL9 Impacts II. Radiative-hydrodynamic Modeling of the Plume Splashback
We model the plume "splashback" phase of the SL9 collisions with Jupiter
using the ZEUS-3D hydrodynamic code. We modified the Zeus code to include gray
radiative transport, and we present validation tests. We couple the infalling
mass and momentum fluxes of SL9 plume material (from paper I) to a jovian
atmospheric model. A strong and complex shock structure results. The modeled
shock temperatures agree well with observations, and the structure and
evolution of the modeled shocks account for the appearance of high excitation
molecular line emission after the peak of the continuum light curve. The
splashback region cools by radial expansion as well as by radiation. The
morphology of our synthetic continuum light curves agree with observations over
a broad wavelength range (0.9 to 12 microns). A feature of our ballistic plume
is a shell of mass at the highest velocities, which we term the "vanguard".
Portions of the vanguard ejected on shallow trajectories produce a lateral
shock front, whose initial expansion accounts for the "third precursors" seen
in the 2-micron light curves of the larger impacts, and for hot methane
emission at early times. Continued propagation of this lateral shock
approximately reproduces the radii, propagation speed, and centroid positions
of the large rings observed at 3-4 microns by McGregor et al. The portion of
the vanguard ejected closer to the vertical falls back with high z-component
velocities just after maximum light, producing CO emission and the "flare" seen
at 0.9 microns. The model also produces secondary maxima ("bounces") whose
amplitudes and periods are in agreement with observations.Comment: 13 pages, 9 figures (figs 3 and 4 in color), accepted for Ap.J.
latex, version including full figures at:
http://oobleck.tn.cornell.edu/jh/ast/papers/slplume2-20.ps.g
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