223 research outputs found

    OO^\star-algebras and quantum dynamics: some existence results

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    We discuss the possibility of defining an algebraic dynamics within the settings of OO^\star-algebras. Compared with our previous results on this subject, the main improvement here is that we are not assuming the existence of some hamiltonian for the {\em full} physical system. We will show that, under suitable conditions, the dynamics can still be defined via some limiting procedure starting from a given {\em regularized sequence}

    SOME ASPECTS OF ENERGY SAVING OF BURDEN MATERIAL IN THE BLAST FURNACE

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    To determine the possibility of self-stabilization effect for burden surface texture and gas flow in operating blast furnace under the proper conditions was experimentally proved for the first time, as well as the reasons of the effect disruption

    Representable states on quasi-local quasi *-algebras

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    Continuing a previous analysis originally motivated by physics, we consider representable states on quasi-local quasi *-algebras, starting with examining the possibility for a {\em compatible} family of {\em local} states to give rise to a {\em global} state. Some properties of {\em local modifications} of representable states and some aspects of their asymptotic behavior are also considered.Comment: In press in Jpurnal of Mathematical Physic

    Assessment of interatomic potentials for atomistic analysis of static and dynamic properties of screw dislocations in W

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    Screw dislocations in bcc metals display non-planar cores at zero temperature which result in high lattice friction and thermally activated strain rate behavior. In bcc W, electronic structure molecular statics calculations reveal a compact, non-degenerate core with an associated Peierls stress between 1.7 and 2.8 GPa. However, a full picture of the dynamic behavior of dislocations can only be gained by using more efficient atomistic simulations based on semiempirical interatomic potentials. In this paper we assess the suitability of five different potentials in terms of static properties relevant to screw dislocations in pure W. As well, we perform molecular dynamics simulations of stress-assisted glide using all five potentials to study the dynamic behavior of screw dislocations under shear stress. Dislocations are seen to display thermally-activated motion in most of the applied stress range, with a gradual transition to a viscous damping regime at high stresses. We find that one potential predicts a core transformation from compact to dissociated at finite temperature that affects the energetics of kink-pair production and impacts the mechanism of motion. We conclude that a modified embedded-atom potential achieves the best compromise in terms of static and dynamic screw dislocation properties, although at an expense of about ten-fold compared to central potentials

    Temporally stable coherent states for infinite well and P\"oschl-Teller potentials

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    This paper is a direct illustration of a construction of coherent states which has been recently proposed by two of us (JPG and JK). We have chosen the example of a particle trapped in an infinite square-well and also in P\"oschl-Teller potentials of the trigonometric type. In the construction of the corresponding coherent states, we take advantage of the simplicity of the solutions, which ultimately stems from the fact they share a common SU(1,1) symmetry \`a la Barut--Girardello. Many properties of these states are then studied, both from mathematical and from physical points of view.Comment: 48 pages, 21 figure

    The influence of transition metal solutes on dislocation core structure and values of Peierls stress and barrier in tungsten

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    Several transition metals were examined to evaluate their potential for improving the ductility of tungsten. The dislocation core structure and Peierls stress and barrier of 1/21/2 screw dislocations in binary tungsten-transition metal alloys (W1x_{1-x}TMx_{x}) were investigated using first principles electronic structure calculations. The periodic quadrupole approach was applied to model the structure of 1/21/2 dislocation. Alloying with transition metals was modeled using the virtual crystal approximation and the applicability of this approach was assessed by calculating the equilibrium lattice parameter and elastic constants of the tungsten alloys. Reasonable agreement was obtained with experimental data and with results obtained from the conventional supercell approach. Increasing the concentration of a transition metal from the VIIIA group, i.e. the elements in columns headed by Fe, Co and Ni, leads to reduction of the CC^\prime elastic constant and increase of elastic anisotropy A=C44/CC_{44}/C^\prime. Alloying W with a group VIIIA transition metal changes the structure of the dislocation core from symmetric to asymmetric, similar to results obtained for W1x_{1-x}Rex_{x} alloys in the earlier work of Romaner {\it et al} (Phys. Rev. Lett. 104, 195503 (2010))\comments{\cite{WRECORE}}. In addition to a change in the core symmetry, the values of the Peierls stress and barrier are reduced. The latter effect could lead to increased ductility in a tungsten-based alloy\comments{\cite{WRECORE}}. Our results demonstrate that alloying with any of the transition metals from the VIIIA group should have similar effect as alloying with Re.Comment: 12 pages, 8 figures, 3 table

    NS1 Specific CD8(+) T-Cells with Effector Function and TRBV11 Dominance in a Patient with Parvovirus B19 Associated Inflammatory Cardiomyopathy

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    Background: Parvovirus B19 (B19V) is the most commonly detected virus in endomyocardial biopsies (EMBs) from patients with inflammatory cardiomyopathy (DCMi). Despite the importance of T-cells in antiviral defense, little is known about the role of B19V specific T-cells in this entity. Methodology and Principal Findings: An exceptionally high B19V viral load in EMBs (115,091 viral copies/mg nucleic acids), peripheral blood mononuclear cells (PBMCs) and serum was measured in a DCMi patient at initial presentation, suggesting B19V viremia. The B19V viral load in EMBs had decreased substantially 6 and 12 months afterwards, and was not traceable in PBMCs and the serum at these times. Using pools of overlapping peptides spanning the whole B19V proteome, strong CD8(+) T-cell responses were elicited to the 10-amico-acid peptides SALKLAIYKA (19.7% of all CD8(+) cells) and QSALKLAIYK (10%) and additional weaker responses to GLCPHCINVG (0.71%) and LLHTDFEQVM (0.06%). Real-time RT-PCR of IFN gamma secretion-assay-enriched T-cells responding to the peptides, SALKLAIYKA and GLCPHCINVG, revealed a disproportionately high T-cell receptor Vbeta (TRBV) 11 expression in this population. Furthermore, dominant expression of type-1 (IFN gamma, IL2, IL27 and Tbet) and of cytotoxic T-cell markers (Perforin and Granzyme B) was found, whereas gene expression indicating type-2 (IL4, GATA3) and regulatory T-cells (FoxP3) was low. Conclusions: Our results indicate that B19V Ag-specific CD8(+) T-cells with effector function are involved in B19V associated DCMi. In particular, a dominant role of TRBV11 and type-1/CTL effector cells in the T-cell mediated antiviral immune response is suggested. The persistence of B19V in the endomyocardium is a likely antigen source for the maintenance of CD8(+) T-cell responses to the identified epitopes

    Evolutionary History of Endogenous Human Herpesvirus 6 Reflects Human Migration out of Africa.

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    Human herpesvirus 6A and 6B (HHV-6) can integrate into the germline, and as a result, ∼70 million people harbor the genome of one of these viruses in every cell of their body. Until now, it has been largely unknown if 1) these integrations are ancient, 2) if they still occur, and 3) whether circulating virus strains differ from integrated ones. Here, we used next-generation sequencing and mining of public human genome data sets to generate the largest and most diverse collection of circulating and integrated HHV-6 genomes studied to date. In genomes of geographically dispersed, only distantly related people, we identified clades of integrated viruses that originated from a single ancestral event, confirming this with fluorescent in situ hybridization to directly observe the integration locus. In contrast to HHV-6B, circulating and integrated HHV-6A sequences form distinct clades, arguing against ongoing integration of circulating HHV-6A or "reactivation" of integrated HHV-6A. Taken together, our study provides the first comprehensive picture of the evolution of HHV-6, and reveals that integration of heritable HHV-6 has occurred since the time of, if not before, human migrations out of Africa

    Genomic expression profiling of human inflammatory cardiomyopathy (DCMi) suggests novel therapeutic targets

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    The clinical phenotype of human dilated cardiomyopathy (DCM) encompasses a broad spectrum of etiologically distinct disorders. As targeting of etiology-related pathogenic pathways may be more efficient than current standard heart failure treatment, we obtained the genomic expression profile of a DCM subtype characterized by cardiac inflammation to identify possible new therapeutic targets in humans. In this inflammatory cardiomyopathy (DCMi), a distinctive cardiac expression pattern not described in any previous study of cardiac disorders was observed. Two significantly altered gene networks of particular interest and possible interdependence centered around the cysteine-rich angiogenic inducer 61 (CYR61) and adiponectin (APN) gene. CYR61 overexpression, as in human DCMi hearts in situ, was similarly induced by inflammatory cytokines in vascular endothelial cells in vitro. APN was strongly downregulated in DCMi hearts and completely abolished cytokine-dependent CYR61 induction in vitro. Dysbalance between the CYR61 and APN networks may play a pathogenic role in DCMi and contain novel therapeutic targets. Multiple immune cell-associated genes were also deregulated (e.g., chemokine ligand 14, interleukin-17D, nuclear factors of activated T cells). In contrast to previous investigations in patients with advanced or end-stage DCM where etiology-related pathomechanisms are overwhelmed by unspecific processes, the deregulations detected in this study occurred at a far less severe and most probably fully reversible disease stage. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00109-006-0122-9 and is accessible for authorized users
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