21,767 research outputs found
Glass transition of binary mixtures of dipolar particles in two dimensions
We study the glass transition of binary mixtures of dipolar particles in two
dimensions within the framework of mode-coupling theory, focusing in particular
on the influence of composition changes. In a first step, we demonstrate that
the experimental system of K\"onig et al. [Eur. Phys. J. E 18, 287 (2005)] is
well described by point dipoles through a comparison between the experimental
partial structure factors and those from our Monte Carlo simulation. For such a
mixture of point particles we show that there is always a plasticization
effect, i.e. a stabilization of the liquid state due to mixing, in contrast to
binary hard disks. We demonstrate that the predicted plasticization effect is
in qualitative agreement with experimental results. Furthermore, also some
general properties of the glass transition lines are discussed.Comment: 12 pages, 8 figures, J. Non-Cryst. Solids (in print
Regulation and Function of the Caspase-1 in an Inflammatory Microenvironment.
The inflammasome is a complex of proteins that has a critical role in mounting an inflammatory response in reply to a harmful stimulus that compromises the homeostatic state of the tissue. The NLRP3 inflammasome, which is found in a wound-like environment, is comprised of three components: the NLRP3, the adaptor protein ASC and caspase-1. Interestingly, although ASC levels do not fluctuate, caspase-1 levels are elevated in both physiological and pathological conditions. Despite the observation that merely raising caspase-1 levels is sufficient to induce inflammation, the crucial question regarding the mechanism governing its expression is unexplored. We found that, in an inflammatory microenvironment, caspase-1 is regulated by NF-κB. Consistent with this association, the inhibition of caspase-1 activity parallels the effects on wound healing caused by the abrogation of NF-κB activation. Surprisingly, not only does inhibition of the NF-κB/caspase-1 axis disrupt the inflammatory phase of the wound-healing program, but it also impairs the stimulation of cutaneous epithelial stem cells of the proliferative phase. These data provide a mechanistic basis for the complex interplay between different phases of the wound-healing response in which the downstream signaling activity of immune cells can kindle the amplification of local stem cells to advance tissue repair
Fast Frictionless Expansion of an Optical Lattice
We investigate fast frictionless expansion of an optical lattice with
dynamically variable spacing (accordion lattice). We design an expansion
trajectory that yields a final state identical to the initial state up to an
irrelevant phase factor. We discuss the effect of additional force and
nonlinear interaction on the fast frictionless expansion.Comment: To be published in PL
Portfolio-based Planning: State of the Art, Common Practice and Open Challenges
In recent years the field of automated planning has significantly
advanced and several powerful domain-independent
planners have been developed. However, none of these systems
clearly outperforms all the others in every known
benchmark domain. This observation motivated the idea of
configuring and exploiting a portfolio of planners to perform
better than any individual planner: some recent planning systems
based on this idea achieved significantly good results in
experimental analysis and International Planning Competitions.
Such results let us suppose that future challenges of the
Automated Planning community will converge on designing
different approaches for combining existing planning algorithms.
This paper reviews existing techniques and provides an exhaustive
guide to portfolio-based planning. In addition, the
paper outlines open issues of existing approaches and highlights
possible future evolution of these techniques
Heart failure and sudden cardiac death in heritable thoracic aortic disease caused by pathogenic variants in the SMAD3 gene
Background: Predominant cardiovascular manifestations in the spectrum of Heritable Thoracic Aortic Disease include by default aortic root aneurysms- and dissections, which may be associated with aortic valve disease. Mitral- and tricuspid valve prolapse are other commonly recognized features. Myocardial disease, characterized by heart failure and/or malignant arrhythmias has been reported in humans and in animal models harboring pathogenic variants in the Fibrillin1 gene.
Methods: Description of clinical history of three cases from one family in Ghent (Belgium) and one family in St. Louis (US).
Results: We report on three cases from two families presenting end-stage heart failure (in two) and lethal arrhythmias associated with moderate left ventricular dilatation (in one). All three cases harbor a pathogenic variant in the SMAD3 gene, known to cause aneurysm osteoarthritis syndrome, Loeys-Dietz syndrome type 3 or isolated Heritable Thoracic Aortic Disease.
Conclusions: These unusual presentations warrant awareness for myocardial disease in patients harboring pathogenic variants in genes causing Heritable Thoracic Aortic Disease and indicate the need for prospective studies in larger cohorts
The diverse constructs use of activities of daily living measures in stroke randomized controlled trials in the years 2005–2009
Objective: To explore construct(s) (ability, capability, actual performance, and/or perceived difficulty) of activities of daily living measures that have been used in randomized controlled trials
The diverse constructs use of activities of daily living measures in stroke randomized controlled trials in the years 2005–2009
Objective: To explore construct(s) (ability, capability, actual performance, and/or perceived difficulty) of activities of daily living measures that have been used in randomized controlled trials
Structure and magnetism of Cr2BP3O12: Towards the quantum-classical crossover in a spin-3/2 alternating chain
Magnetic properties of the spin-3/2 Heisenberg system Cr2BP3O12 are
investigated by magnetic susceptibility chi(T) measurements, electron spin
resonance, neutron diffraction, and density functional theory (DFT)
calculations, as well as classical and quantum Monte Carlo (MC) simulations.
The broad maximum of chi(T) at 85K and the antiferromagnetic Weiss temperature
of 139 K indicate low-dimensional magnetic behavior. Below TN = 28 K, Cr2BP3O12
is antiferromagnetically ordered with the k = 0 propagation vector and an
ordered moment of 2.5 muB/Cr. DFT calculations, including DFT+U and hybrid
functionals, yield a microscopic model of spin chains with alternating
nearest-neighbor couplings J1 and J1' . The chains are coupled by two
inequivalent interchain exchanges of similar strength (~1-2 K), but different
sign (antiferromagnetic and ferromagnetic). The resulting spin lattice is
quasi-one-dimensional and not frustrated. Quantum MC simulations show excellent
agreement with the experimental data for the parameters J1 ~= 50 K and J1'/J1
~= 0.5. Therefore, Cr2BP3O12 is close to the gapless critical point (J1'/J1 =
0.41) of the spin-3/2 bond-alternating Heisenberg chain. The applicability
limits of the classical approximation are addressed by quantum and classical MC
simulations. Implications for a wide range of low-dimensional S = 3/2 materials
are discussed.Comment: Published version: 13 pages, 7 figures, 5 tables + Supplementary
informatio
Diacetylene bridged triphenylamines as hole transport materials for solid state dye sensitized solar cells
We have synthesized and characterized a series of triphenylamine-based hole-transport materials (HTMs), and studied their function in solid-state dye sensitized solar cells (ss-DSSCs). By increasing the electron-donating strength of functional groups (-H < -Me < -SMe < -OMe) we have systematically shifted the oxidation potential and ensuing photocurrent generation and open-circuit voltage of the solar cells. Correlating the electronic properties of the HTM to the device operation highlights a significant energy offset required between the Dye-HTM highest occupied molecular orbital (HOMO) energy levels. From this study, it is apparent that precise control and tuning of the oxidation potential is a necessity, and usually not achieved with most HTMs developed to date for ss-DSSCs. To significantly increase the efficiency of solid-state DSSCs understanding these properties, and implementing dye-HTM combinations to minimize the required HOMO offset is of central importance. © 2013 The Royal Society of Chemistry
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