1,544 research outputs found
Kidney injury molecule-1 expression in transplant biopsies is a sensitive measure of cell injury
Kidney injury molecule-1 (KIM-1) is a specific histological biomarker for diagnosing early tubular injury on renal biopsies. In this study, KIM-1 expression was quantitated in renal transplant biopsies by immunohistochemistry and correlated with renal function. None of the 25 protocol biopsies showed detectable tubular injury on histologic examination, yet 28% had focal positive KIM-1 expression. Proximal tubule KIM-1 expression was present in all biopsies from patients with histological changes showing acute tubular damage and deterioration of kidney function. In this group, higher KIM-1 staining predicted a better outcome with improved blood urea nitrogen (BUN), serum creatinine, and estimated glomerular filtration rate (eGFR) over an ensuing 18 months. KIM-1 was expressed focally in affected tubules in 92% of kidney biopsies from patients with acute cellular rejection. By contrast, there was little positive staining for Ki-67, a cell proliferation marker, in any of the groups. KIM-1 expression significantly correlated with serum creatinine and BUN, and inversely with the eGFR on the biopsy day. Our study shows that KIM-1 staining sensitively and specifically identified proximal tubular injury and correlated with the degree of renal dysfunction. KIM-1 expression is more sensitive than histology for detecting early tubular injury, and its level of expression in transplant biopsies may indicate the potential for recovery of kidney function
Preparation of polarization entangled mixed states of two photons
We propose a scheme for preparing arbitrary two photons polarization
entangled mixed states via controlled location decoherence. The scheme uses
only linear optical devices and single-mode optical fibers, and may be feasible
in experiment within current optical technology.Comment: 3 pages, 5 figs. The article has been rewritten. Discussion about
experiment are added. To appear in Phys. Rev.
Frozen thermal fluctuations in adsorbate-induced step restructuring
Ammonia adsorbed on a Pt(443) surface causes meandering of the initially straight edges at 300 K. Based on density-functional theory calculations and on kinetic Monte Carlo simulations it is shown that the meandering is not an equilibrium structure stabilized by the larger adsorption energy of ammonia at step and kink sites. Rather the meandering has to be interpreted as a frozen thermal fluctuation caused by ammonia which strongly reduces the stiffness of the step edges at intermediate ammonia coverages
Relaxation kinetics in two-dimensional structures
We have studied the approach to equilibrium of islands and pores in two
dimensions. The two-regime scenario observed when islands evolve according to a
set of particular rules, namely relaxation by steps at low temperature and
smooth at high temperature, is generalized to a wide class of kinetic models
and the two kinds of structures. Scaling laws for equilibration times are
analytically derived and confirmed by kinetic Monte Carlo simulations.Comment: 6 pages, 7 figures, 1 tabl
Entanglement in the One-dimensional Kondo Necklace Model
We discuss the thermal and magnetic entanglement in the one-dimensional Kondo
necklace model. Firstly, we show how the entanglement naturally present at zero
temperature is distributed among pairs of spins according to the strength of
the two couplings of the chain, namely, the Kondo exchange interaction and the
hopping energy. The effect of the temperature and the presence of an external
magnetic field is then investigated, being discussed the adjustment of these
variables in order to control the entanglement available in the system. In
particular, it is indicated the existence of a critical magnetic field above
which the entanglement undergoes a sharp variation, leading the ground state to
a completely unentangled phase.Comment: 8 pages, 13 EPS figures. v2: four references adde
Entanglement Sudden Death in Band Gaps
Using the pseudomode method, we evaluate exactly time-dependent entanglement
for two independent qubits, each coupled to a non-Markovian structured
environment. Our results suggest a possible way to control entanglement sudden
death by modifying the qubit-pseudomode detuning and the spectrum of the
reservoirs. Particularly, in environments structured by a model of a
density-of-states gap which has two poles, entanglement trapping and prevention
of entanglement sudden death occur in the weak-coupling regime
Quantum teleportation of light beams
We experimentally demonstrate quantum teleportation for continuous variables
using squeezed-state entanglement. The teleportation fidelity for a real
experimental system is calculated explicitly, including relevant imperfection
factors such as propagation losses, detection inefficiencies and phase
fluctuations. The inferred fidelity for input coherent states is F = 0.61 +-
0.02, which when corrected for the efficiency of detection by the output
observer, gives a fidelity of 0.62. By contrast, the projected result based on
the independently measured entanglement and efficiencies is 0.69. The
teleportation protocol is explained in detail, including a discussion of
discrepancy between experiment and theory, as well as of the limitations of the
current apparatus.Comment: 17 pages, 19 figures, submitted to PR
Optimal discrimination of mixed quantum states involving inconclusive results
We propose a generalized discrimination scheme for mixed quantum states. In
the present scenario we allow for certain fixed fraction of inconclusive
results and we maximize the success rate of the quantum-state discrimination.
This protocol interpolates between the Ivanovic-Dieks-Peres scheme and the
Helstrom one. We formulate the extremal equations for the optimal positive
operator valued measure describing the discrimination device and establish a
criterion for its optimality. We also devise a numerical method for efficient
solving of these extremal equations.Comment: 5 pages, 1 figur
Modular Equations and Distortion Functions
Modular equations occur in number theory, but it is less known that such
equations also occur in the study of deformation properties of quasiconformal
mappings. The authors study two important plane quasiconformal distortion
functions, obtaining monotonicity and convexity properties, and finding sharp
bounds for them. Applications are provided that relate to the quasiconformal
Schwarz Lemma and to Schottky's Theorem. These results also yield new bounds
for singular values of complete elliptic integrals.Comment: 23 page
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