34 research outputs found
Full quantum solutions to the resonant four-wave mixing of two single-photon wave packets
We analyze both analytically and numerically the resonant four-wave mixing of
two co-propagating single-photon wave packets. We present analytic expressions
for the two-photon wave function and show that soliton-type quantum solutions
exist which display a shape-preserving oscillatory exchange of excitations
between the modes. Potential applications including quantum information
processing are discussed.Comment: 7 pages, 3 figure
Quantum theory of resonantly enhanced four-wave mixing: mean-field and exact numerical solutions
We present a full quantum analysis of resonant forward four-wave mixing based
on electromagnetically induced transparency (EIT). In particular, we study the
regime of efficient nonlinear conversion with low-intensity fields that has
been predicted from a semiclassical analysis. We derive an effective nonlinear
interaction Hamiltonian in the adiabatic limit. In contrast to conventional
nonlinear optics this Hamiltonian does not have a power expansion in the fields
and the conversion length increases with the input power. We analyze the
stationary wave-mixing process in the forward scattering configuration using an
exact numerical analysis for up to input photons and compare the results
with a mean-field approach. Due to quantum effects, complete conversion from
the two pump fields into the signal and idler modes is achieved only
asymptotically for large coherent pump intensities or for pump fields in
few-photon Fock states. The signal and idler fields are perfectly quantum
correlated which has potential applications in quantum communication schemes.
We also discuss the implementation of a single-photon phase gate for continuous
quantum computation.Comment: 10 pages, 11 figure
IL-13 and IL-4, but not IL-5 nor IL-17A, induce hyperresponsiveness in isolated human small airways
BACKGROUND:Specific inflammatory pathways are indicated to contribute to severe asthma, but their individual involvement in the development of airway hyperresponsiveness remains unexplored. OBJECTIVE:This experimental study in human small bronchi aimed to provide insight into which of the type 2 and type 17 cytokines cause hyperresponsiveness of airway smooth muscle. METHODS:Explanted small bronchi isolated from human lung tissue and human airway smooth muscle cells were treated for 2 and 1 day(s), respectively, with 100 ng/mL of IL-4, IL-5, IL-13, or IL-17A, and contractile responses, Ca2+ mobilization, and receptor expression were assessed. RESULTS:Treatment with IL-13 increased the potency of histamine, carbachol, and leukotriene D4 as contractile agonists. IL-4, but not IL-5 or IL-17A, also increased the potency of histamine. In human airway smooth muscle cells, IL-13 and IL-4, but not IL-5 and IL-17A, enhanced the histamine-induced Ca2+ mobilization that was accompanied with increased mRNA expression of histamine H1 and cysteinyl leukotriene CysLT1 receptors. RNA sequencing of isolated bronchi confirmed the IL-13-mediated upregulation of H1 and CysLT1 receptors, without showing an alteration of muscarinic M3 receptors. Dexamethasone had no effects on IL-13-induced hyperresponsiveness in human bronchi, the increased Ca2+ mobilization, or the enhanced receptor expression. In contrast, antagonism of the common receptor for IL-13 and IL-4 by the biologic dupilumab prevented the effects of both IL-13 and IL-4 in human bronchi and human airway smooth muscle cells. CONCLUSIONS:The glucocorticoid-insensitive hyperrresponsiveness in isolated human airways induced by IL-13 and IL-4 provides further evidence that the IL-4Rα pathway should be targeted as a new strategy for the treatment of airway hyperresponsiveness in asthma.FWN â Publicaties zonder aanstelling Universiteit Leide
Magnetization of coupled spin clusters in Ladder Geometry
In this paper, we construct a class of spin-1/2 antiferromagnetic (AFM)
two-chain ladder models consisting of blocks of n-spin tetrahedral clusters
alternating with two-spin rungs. For n=4 and 6 and in extended parameter
regimes, the exact ground state of the ladder is shown to be a product of the
ground states of the rungs and the n-spin blocks, in both zero and finite
magnetic fields. In the latter case, magnetization/site (m) versus magenetic
field (h) plot exhibits well-defined magnetization plateaus.Comment: 9 pages, latex, 6 figures, To be published in Phys. Rev.
A numerical simulation analysis of the effect of the interface drag function on cluster evolution in a CFB riser gas-solid flow
Effect of photoperiod on locomotor activity, growth, feed efficiency and gonadal development of Nile tilapia
New records of Monstrilloida Sars, 1901 (Crustacea: Copepoda) from Rio Grande do Norte (northeastern coast of Brazil)
Effect of solute on the growth rate and the constitutional undercooling ahead of the advancing interface during solidification of an alloy and the implications for nucleation
A framework is presented for modeling the nucleation in the constitutionally supercooled liquid ahead of the advancing solid/liquid interface. The effects of temperature gradient, imposed velocity, slope of liquidus, and initial concentration have been taken into account in this model by considering the effect of interface retardation, which is caused by solute buildup at the interface. Furthermore, the effect of solute concentration on the chemical driving force for nucleation has been considered in this model. The model is used for describing the nucleation of Al-Si and Al-Cu alloys. It was found that the solute of Si has a significant impact on the chemical driving force for nucleation in AI-Si alloys whereas Cu has almost no effect in Al-Cu alloys