8,821 research outputs found
Novel Method to Process Cystic Fibrosis Sputum for Determination of Oxidative State
Background: Induced sputum is the most commonly used method to analyze airway inflammation in cystic fibrosis (CF) patients ex vivo. Due to the complex matrix of the sample material, precise and reliable analysis of sputum constituents depends critically on preanalytical issues. Objectives: Here we compared the commonly used method for sputum processing by dithiothreitol (DTT) with a novel mechanical method in regard to basal cellular parameters, neutrophil markers and glutathione (GSH) levels. Methods: Sputum samples from CF patients were processed in parallel with or without the use of DTT. The key improvement of the mechanical method was the processing in many very small aliquots. Cellular and humoral markers were assessed and compared according to Bland-Altman. Results: Total cell count, cell viability, differential cell count, neutrophil elastase levels and flow cytometrically analyzed neutrophil markers (CD63, CD11b, DHR) did not differ between the two methods. Intracellular and extracellular GSH levels were significantly higher in DTT-treated samples (p = 0.002). Conclusion: The mechanical sputum-processing method presented had a similar yield of cells and fluids as the conventional DTT method and the advantage of omitting the introduction of reducing agents. This method allows a more reliable analysis of redox-dependent airway inflammation in sputum cells and fluid from CF patients than methods utilizing DTT. Copyright (C) 2009 S. Karger AG, Base
Cavity state preparation using adiabatic transfer
We show how to prepare a variety of cavity field states for multiple
cavities. The state preparation technique used is related to the method of
stimulated adiabatic Raman passage or STIRAP. The cavity modes are coupled by
atoms, making it possible to transfer an arbitrary cavity field state from one
cavity to another, and also to prepare non-trivial cavity field states. In
particular, we show how to prepare entangled states of two or more cavities,
such as an EPR state and a W state, as well as various entangled superpositions
of coherent states in different cavities, including Schrodinger cat states. The
theoretical considerations are supported by numerical simulations.Comment: 11 pages, 9 figures. Accepted in Phys. Rev.
Noise Properties of Superconducting Coplanar Waveguide Microwave Resonators
We have measured noise in thin-film superconducting coplanar waveguide
resonators. This noise appears entirely as phase noise, equivalent to a jitter
of the resonance frequency. In contrast, amplitude fluctuations are not
observed at the sensitivity of our measurement. The ratio between the noise
power in the phase and amplitude directions is large, in excess of 30 dB. These
results have important implications for resonant readouts of various devices
such as detectors, amplifiers, and qubits. We suggest that the phase noise is
due to two-level systems in dielectric materials.Comment: 4 pages, 3 figures, accepted for publication in Applied Physics
Letter
Spectrum of Andreev Bound States in a Molecule Embedded Inside a Microwave-Excited Superconducting Junction
Non-dissipative Josephson current through nanoscale superconducting
constrictions is carried by spectroscopically sharp energy states, so-called
Andreev bound states. Although theoretically predicted almost 40 years ago, no
direct spectroscopic evidence of these Andreev bound states exists to date. We
propose a novel type of spectroscopy based on embedding a superconducting
constriction, formed by a single-level molecule junction, in a microwave QED
cavity environment. In the electron-dressed cavity spectrum we find a polariton
excitation at twice the Andreev bound state energy, and a superconducting-phase
dependent ac Stark shift of the cavity frequency. Dispersive measurement of
this frequency shift can be used for Andreev bound state spectroscopy.Comment: Published version; 4+ pages, 3 figure
Characterization of cyclic nucleotide phosphodiesterase isoenzymes in the human ureter and their functional role in vitro
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