25,880 research outputs found
Immune Modulation as a Treatment for Abdominal Aortic Aneurysms
In the United States, over 200,000 new patients are diagnosed with abdominal aortic aneurysm (AAA) each year. Consequently, over 40,000 highly morbid aortic reconstructions are performed each year to prevent aneurysm rupture, a catastrophic event associated with near-certain mortality. No pharmaceutical currently exists to slow aneurysm growth, but a 50% reduction in diameter growth per annum could halve the number of aortic reconstructions required. Therefore, successful use of cell therapy to modulate chronic inflammation hallmark to AAA to slow diameter expansion represents a potentially paradigm-altering treatment
Ordered Array of Single Au Adatoms with Remarkable Thermal Stability: Au/Fe3O4(001)
We present a Scanning Tunneling Microscopy (STM) investigation of gold
deposited at the magnetite Fe3O4(001) surface at room temperature. This surface
forms a reconstruction with (\surd2\times\surd2)R45{\deg} symmetry, where pairs
of Fe and neighboring O ions are slightly displaced laterally, forming
undulating rows with 'narrow' and 'wide' adsorption sites. At fractional
monolayer coverages, single Au adatoms adsorb exclusively at the narrow sites,
with no significant sintering up to annealing temperatures of 400 {\deg}C. The
strong preference for this site is possibly related to charge and orbital
ordering within the first subsurface layer of the reconstructed Fe3O4(001)
surface. Because of their high thermal stability, the ordered Au atoms at
Fe3O4(001)- (\surd2\times\surd2)R45{\deg} could provide useful for probing the
chemical reactivity of single atomic species.Comment: Duplicate entry, newer version at 1205.0915.
http://arxiv.org/abs/1205.091
Observation of topological transition of Fermi surface from a spindle-torus to a torus in large bulk Rashba spin-split BiTeCl
The recently observed large Rashba-type spin splitting in the BiTeX (X = I,
Br, Cl) bulk states due to the absence of inversion asymmetry and large charge
polarity enables observation of the transition in Fermi surface topology from
spindle-torus to torus with varying the carrier density. These BiTeX systems
with high spin-orbit energy scales offer an ideal platform for achieving
practical spintronic applications and realizing non-trivial phenomena such as
topological superconductivity and Majorana fermions. Here we use Shubnikov-de
Haas oscillations to investigate the electronic structure of the bulk
conduction band of BiTeCl single crystals with different carrier densities. We
observe the topological transition of the Fermi surface (FS) from a
spindle-torus to a torus. The Landau level fan diagram reveals the expected
non-trivial {\pi} Berry phase for both the inner and outer FSs. Angle-dependent
oscillation measurements reveal three-dimensional FS topology when the Fermi
level lies in the vicinity of the Dirac point. All the observations are
consistent with large Rashba spin-orbit splitting in the bulk conduction band.Comment: 28 pages, supplementary informatio
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