2,667 research outputs found
Reweighting towards the chiral limit
We propose to perform fully dynamical simulations at small quark masses by
reweighting in the quark mass. This approach avoids some of the technical
difficulties associated with direct simulations at very small quark masses. We
calculate the weight factors stochastically, using determinant breakup and low
mode projection to reduce the statistical fluctuations. We find that the weight
factors fluctuate only moderately on nHYP smeared dynamical Wilson-clover
ensembles, and we could successfully reweight 16^4, (1.85fm)^4 volume
configurations from m_q = 20MeV to m_q = 5MeV quark masses, reaching the
epsilon-regime. We illustrate the strength of the method by calculating the low
energy constant F from the epsilon-regime pseudo-scalar correlator.Comment: 17 pages, 8 figure
Reduced Coulomb interaction in organic solar cells by the introduction of inorganic high-k nanostructured materials
In this article a concept is introduced, which allows for reduced Coulomb
interaction in organic solar cells and as such for enhanced power conversion
efficiencies. The concept is based on the introduction of electrically
insulating, nanostructured high-k materials into the organic matrix, which do
not contribute to the charge transport, however, effectively enhance the
permittivity of the organic active layer and thereby reduce the Coulomb
interaction. Using an analytical model it is demonstrated that even at a
distance of 20 nm to the organic / inorganic interface of the nanostructure,
the Coulomb interaction can be reduced by more than 15 %. The concept is
implemented using P3HT:PCBM solar cells with integrated high-k nanoparticles
(strontium titanate). It could be demonstrated that in comparison to a
reference cell without integrated nanoparticles, the power conversion
efficiencies could be improved by ~20 %.Comment: 11 pages, 7 figure
The matricellular functions of small leucine-rich proteoglycans (SLRPs)
The small leucine-rich proteoglycans (SLRPs) are biologically active components of the extracellular matrix (ECM), consisting of a protein core with leucine rich-repeat (LRR) motifs covalently linked to glycosaminoglycan (GAG) side chains. The diversity in composition resulting from the various combinations of protein cores substituted with one or more GAG chains along with their pericellular localization enables SLRPs to interact with a host of different cell surface receptors, cytokines, growth factors, and other ECM components, leading to modulation of cellular functions. SLRPs are capable of binding to: (i) different types of collagens, thereby regulating fibril assembly, organization, and degradation; (ii) Toll-like receptors (TLRs), complement C1q, and tumor necrosis factor-alpha (TNFα), regulating innate immunity and inflammation; (iii) epidermal growth factor receptor (EGF-R), insulin-like growth factor receptor (IGF-IR), and c-Met, influencing cellular proliferation, survival, adhesion, migration, tumor growth and metastasis as well as synthesis of other ECM components; (iv) low-density lipoprotein receptor-related protein (LRP-1) and TGF-β, modulating cytokine activity and fibrogenesis; and (v) growth factors such as bone morphogenic protein (BMP-4) and Wnt-I-induced secreted protein-1 (WISP-1), controlling cell proliferation and differentiation. Thus, the ability of SLRPs, as ECM components, to directly or indirectly regulate cell-matrix crosstalk, resulting in the modulation of various biological processes, aptly qualifies these compounds as matricellular proteins
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