12,485 research outputs found
The unique rapid variabilities of the iron K line profiles in NGC 4151
We present a detailed analysis of the iron K line variabilities in
NGC 4151 by using long ASCA observation data obtained in May 1995. Despite the
relatively small amplitude variations in the continuum flux, the iron K
line flux and profile show dramatic variations. Particularly, the line profile
changes from single peak to seeming double peaks and back in time scales of a
few 10 sec. The seemingly double-peaked profiles can be well interpreted as
line emission from a Keplerian ring around a massive black hole. An absorption
line at around 5.9 keV is also marginnaly detected. We discussed current Fe K
line models, but none of them can well explain the observed line and continuum
variations.Comment: 18 pages, latex, 3 figures, ApJ accepte
Vortex solutions in axial or chiral coupled non-relativistic spinor- Chern-Simons theory
The interaction of a spin 1/2 particle (described by the non-relativistic
"Dirac" equation of L\'evy-Leblond) with Chern-Simons gauge fields is studied.
It is shown, that similarly to the four dimensional spinor models, there is a
consistent possibility of coupling them also by axial or chiral type currents.
Static self dual vortex solutions together with a vortex-lattice are found with
the new couplings.Comment: Plain TEX, 10 page
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Distinct ligand binding sites in integrin alpha3beta1 regulate matrix adhesion and cell-cell contact.
The integrin alpha3beta1 mediates cellular adhesion to the matrix ligand laminin-5. A second integrin ligand, the urokinase receptor (uPAR), associates with alpha3beta1 via a surface loop within the alpha3 beta-propeller (residues 242-246) but outside the laminin binding region, suggesting that uPAR-integrin interactions could signal differently from matrix engagement. To explore this, alpha3-/- epithelial cells were reconstituted with wild-type (wt) alpha3 or alpha3 with Ala mutations within the uPAR-interacting loop (H245A or R244A). Wt or mutant-bearing cells showed comparable expression and adhesion to laminin-5. Cells expressing wt alpha3 and uPAR dissociated in culture, with increased Src activity, up-regulation of SLUG, and down-regulation of E-cadherin and gamma-catenin. Src kinase inhibition or expression of Src 1-251 restored the epithelial phenotype. The H245A and R244A mutants were unaffected by coexpression of uPAR. We conclude that alpha3beta1 regulates both cell-cell contact and matrix adhesion, but through distinct protein interaction sites within its beta-propeller. These studies reveal an integrin- and Src-dependent pathway for SLUG expression and mesenchymal transition
Conductance Characteristics between a Normal Metal and a Superconductor Carrying a Supercurrent
The low-temperature conductance (G) characteristics between a normal metal
and a clean superconductor (S) carrying a supercurrent parallel to the
interface is theoretically investigated. Increasing causes lowering and
broadening of (1) coherence peaks of s-wave S, and d-wave S at (100) contact,
(2) midgap-states-induced zero-bias conductance peak for d-wave S at (110)
contact, and (3) Andreev-reflection-induced enhancement of within the gap
near the metallic-contact limit. Novel features found include a current-induced
central peak and a three-humped structure at intermediate barrier strength,
etc.Comment: 4 pages, 4 figure
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