646 research outputs found
Optical properties of two-dimensional honeycomb crystals graphene, silicene, germanene, and tinene from first principles
No full textWe compute the optical conductivity of 2D honeycomb crystals beyond the usual Dirac-cone approximation. The calculations are mainly based on the independent-quasiparticle approximation of the complex dielectric function for optical interband transitions. The full band structures are taken into account. In the case of silicene, the influence of excitonic effects is also studied. Special care is taken to derive converged spectra with respect to the number of k points in the Brillouin zone and the number of bands. In this way both the real and imaginary parts of the optical conductivity are correctly described for small and large frequencies. The results are applied to predict the optical properties reflection, transmission and absorption in a wide range of photon energies. They are discussed in the light of the available experimental data
Multilateralism or Regionalism? Trade Policy Options for the European Union. CEPS Paperback. December 2005
No full textRegional trade agreements play an ever-increasing role in world trade, accounting for more than 50% of global transactions today. Recently such large players as the US, Japan and many emerging countries have begun to conclude multiple bilateral trade agreements. At the same time, the EU, being a pioneer of this strategy, has declared a moratorium on new regional trade negotiations. Meanwhile, negotiations within the Doha Development Agenda are dragging along, without producing any tangible results from the EU’s perspective. This new report, by Guido Glania (Federation of German Industries) and Jürgen Matthes (Cologne Institute for Economic Research), takes up and enriches the large body of academic research to highlight the multifaceted effects of regional trade agreements and draws on the authors’ practical experience to outline the strategic options for EU trade policy. The report points out what is new about this most recent phase of regionalism and analyses the differentiated effects on economic welfare and trade transaction costs. A particular focus lies in the multiple impacts of regionalism on the WTO and the multilateral trading order. Against this background, the options for EU trade policy are examined with a particular focus on the possible merits of plurilateral approaches within the WTO
The bcl, NF kappa B and p53/p21(WAF1) systems are involved in spontaneous apoptosis and in the anti-apoptotic effect of TGF-beta or TNF-alpha on activated hepatic stellate cells
No full textActivated hepatic stellate cells (HSC) are thought to play a pivotal role in development of liver fibrosis which takes place in chronic liver diseases. Previous studies have shown that "activated" rat HSC undergo spontaneous apoptosis probably through the CD95/CD95L pathway. TGF-beta as well as TNF-alpha reduced spontaneous apoptosis and CD95L expression. The aim of this study was to investigate the possible mechanisms responsible for the spontaneous apoptosis and for the anti-apoptotic effect of TGF-beta and TNF-alpha on activated HSC. While bcl-2, bax, NF kappaB and p53 gene expression were spontaneously upregulated, bcl-x(L) and p21(WAF1) gene expression decreased and I kappaB remained unchanged during the activation process in vitro. TGF-P as well as TNF-a induced activation of NF kappaB and upregulated bcl-x(L). The latter was inhibited by overexpression of I kappaB. By suppressing spontaneous apoptosis TGF-beta as well as TNF-alpha inhibited p53 gene expression while that of the p21(WAF1) gene was increased. We conclude that TGF-beta as well as TNF-alpha may act as surviving factors for activated rat HSC not only through reduction of CD95L gene expression but also by upregulating the anti-apoptotic factors NF kappaB, bcl-x(L) and p21(WAF1) and by downregulating the proapoptotic factor p53. The interaction with these factors may lead to the generation of new antifibrotic drugs
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No full textVorlageform des Erscheinungsvermerks: Bey Matthes Welack gedruckt.|| ANNO M.D.LXXXVI.|| [Wittenberg]Leyser, Polykarp: Predigt bei traurigem Begängnis der ... Frauen ... Anna, gebornen aus königlichem Stammen Dänemark ... s. k. f. Ehegemahlin. (VD16 L 1463
Correction to: The relative risk of second primary cancers in Switzerland: a population-based retrospective cohort study
No full textFollowing publication of the original article: Feller A, Matthes KL, Bordoni A, et al. The relative risk of second primary cancers in Switzerland: a population-based retrospective cohort study. BMC Cancer. 2020;20:51. doi: 10.1186/s12885-019-6452-0.
An error was reported in the author group
A Boltzmann-type Approach to the Formation of Wealth Distribution Curves
No full textKinetic market models have been proposed recently to account for the redistribution of wealth in simple market economies. These models allow to develop a qualitative theory, which is based on methods borrowed from the kinetic theory of rarefied gases. The aim of these notes is to present a unifying approach to the study of the evolution of wealth in the large- time regime. The considered models are divided into two classes: the first class is such that the society’s mean wealth is conserved, while for models of the second class, the mean wealth grows or decreases exponentially in time. In both cases, it is possible to classify the most important feature of the steady (or self-similar, respectively) wealth distributions, namely the fatness of the Pareto tail. We shall also discuss the tails’ dynamical stability in terms of the model parameters. Our results are derived by means of a qualitative analysis of the associated homogeneous Boltzmann equations. The key tools are suitable metrics for probability measures, and a concise description of the evolution of moments. A recent extension to economies, in which different groups of agents interact, is presented in detail. We conclude with numerical experiments that confirm the theo- retical predictions.
Weak Completeness of Coalgebraic Dynamic Logics
No full textWe present a coalgebraic generalisation of Fischer and Ladner’s Propositional Dynamic Logic (PDL) and Parikh’s Game Logic (GL). In earlier work, we proved a generic strong completeness result for coalgebraic dynamic logics without iteration. The coalgebraic semantics of such programs is given by a monad T, and modalities are interpreted via a predicate lifting l whose transpose is a monad morphism from T to the neighbourhood monad. In this paper, we show that if the monad T carries a complete semilattice structure, then we can define an iteration construct, and suitable notions of diamond-likeness and box-likeness of predicate-liftings which allows for the definition of an axiomatisation parametric in T, l and a chosen set of pointwise program operations. As our main result, we show that if the pointwise operations are “negation-free” and Kleisli composition left-distributes over the induced join on Kleisli arrows, then this axiomatisation is weakly complete with respect to the class of standard models. As special instances, we recover the weak completeness of PDL and of dual-free Game Logic. As a modest new result we obtain completeness for dual-free GL extended with intersection (demonic choice) of games.Engineering, Systems and ServicesTechnology, Policy and Managemen
Effect of MANT-nucleotides on L-type calcium currents in murine cardiomyocytes
No full textMembranous adenylyl cyclases play a major role in G-protein-coupled receptor signalling and regulate various cellular responses, such as cardiac contraction. Cardiac apoptosis and development of cardiac dysfunction is prevented in mice lacking AC 5, a predominant isoform in the heart. In the search for a potent and selective AC 5 inhibitor, we recently identified 2'(3')-methylanthraniloyl-inosine-5'-triphosphate(MANT-ITP) as the most potent AC 5 inhibitor with a K (i) of 13 nM. Therefore, AC inhibition of MANT-ITP was assessed in ventricular cardiomyocytes and compared to three other MANT-nucleotides to evaluate its effect on cardiac signalling. Basal and isoproterenol-induced L-type calcium currents (I (Ca,L)) in murine ventricular cardiomyocytes were recorded by whole-cell patch-clamp technique, using four different MANT-nucleotides. The effects of the MANT-nucleotides on I (Ca,L) were unexpectedly complex. All MANT-nucleotides exhibited an inhibitory effect on basal I (Ca,L). Additionally, several MANT-nucleotides, i.e., MANT-ITP gamma S, MANT-ATP, and MANT-ITP, caused a strong initial increase in basal I (Ca,L) within the first 2.5 min that appeared to be unrelated to AC 5 inhibition. However, we detected a significant reduction on isoproterenol-induced I (Ca,L) with MANT-ITP, supporting the notion that AC 5 plays an important role in agonist-stimulated activation of I (Ca,L). Collectively, MANT-nucleotides are useful tools for the characterization of recombinant ACs, for fluorescence studies and crystallography, but in intact cardiomyocytes, caution must be exerted since MANT-nucleotides apparently possess additional effects than AC 5 inhibition, limiting their usefulness as tools for intact cell studies
Spontaneous Aggregation of the Insulin-Derived Steric Zipper Peptide VEALYL Results in Different Aggregation Forms with Common Features
No full textAbstractRecently, several short peptides have been shown to self-assemble into amyloid fibrils with generic cross-β spines, so-called steric zippers, suggesting common underlying structural features and aggregation mechanisms. Understanding these mechanisms is a prerequisite for designing fibril-binding compounds and inhibitors of fibril formation. The hexapeptide VEALYL, corresponding to the residues B12-17 of full-length insulin, has been identified as one of these short segments. Here, we analyzed the structures of multiple, morphologically different (fibrillar, microcrystal-like, oligomeric) [13C,15N]VEALYL samples by solid-state nuclear magnetic resonance complemented with results from molecular dynamics simulations. By performing NHHC/CHHC experiments, we could determine that the β-strands within a given sheet of the amyloid-like fibrils formed by the insulin hexapeptide VEALYL are stacked in an antiparallel manner, whereas the sheet-to-sheet packing arrangement was found to be parallel. Experimentally observed secondary chemical shifts for all aggregate forms, as well as ∅ and ψ backbone torsion angles calculated with TALOS, are indicative of β-strand conformation, consistent with the published crystal structure (PDB ID: 2OMQ). Thus, we could demonstrate that the structural features of all the observed VEALYL aggregates are in agreement with the previously observed homosteric zipper spine packing in the crystalline state, suggesting that several distinct aggregate morphologies share the same molecular architecture
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