70 research outputs found
Statistical field theories deformed within different calculi
Within framework of basic-deformed and finite-difference calculi, as well as
deformation procedures proposed by Tsallis, Abe, and Kaniadakis to be
generalized by Naudts, we develop field-theoretical schemes of statistically
distributed fields. We construct a set of generating functionals and find their
connection with corresponding correlators for basic-deformed,
finite-difference, and Kaniadakis calculi. Moreover, we introduce pair of
additive functionals, whose expansions into deformed series yield both Green
functions and their irreducible proper vertices. We find as well formal
equations, governing by the generating functionals of systems which possess a
symmetry with respect to a field variation and are subjected to an arbitrary
constrain. Finally, we generalize field-theoretical schemes inherent in
concrete calculi in the Naudts spirit.Comment: 12 pages, 3 figure
Analytical and numerical studies of creation probabilities of hierarchical trees
We consider the creation conditions of diverse hierarchical trees both
analytically and numerically. A connection between the probabilities to create
hierarchical levels and the probability to associate these levels into a united
structure is studied. We argue that a consistent probabilistic picture requires
the use of deformed algebra. Our consideration is based on the study of the
main types of hierarchical trees, among which both regular and degenerate ones
are studied analytically, while the creation probabilities of Fibonacci,
scale-free and arbitrary trees are determined numerically.Comment: 6 pages, 3 figure
Noise induced oscillations in non-equilibrium steady state systems
We consider effect of stochastic sources upon self-organization process being
initiated with creation of the limit cycle. General expressions obtained are
applied to the stochastic Lorenz system to show that departure from equilibrium
steady state can destroy the limit cycle at certain relation between
characteristic scales of temporal variation of principle variables. Noise
induced resonance related to the limit cycle is found to appear if the fastest
variations displays a principle variable, which is coupled with two different
degrees of freedom or more.Comment: 11 pages, 4 figures. Submitted to Physica Script
Phase field modelling voids nucleation and growth in binary systems
We present a comprehensive study of voids formation, nucleation and growth in
a prototype model of binary alloys subjected to irradiation by using a combined
approach based on phase field and rate theories. It is shown that voids
formation is caused by interaction of irradiation-produced vacancies through
elastic deformation of a lattice and vacancy coupling with composition field of
the alloy. Phase diagrams illustrating the formation of states related to solid
solution, phase decomposition, and patterning are obtained. Formation of voids
from supersaturated ensemble of vacancies is accompanied by composition
rearrangement of alloy components. It was found that elastic inhomogeneity
leading to the formation of anisotropic precipitates in an initially prepared
binary alloy results in the formation of a void super-lattice under
irradiation. It was shown that voids nucleate and grow with dose according to
diffusion controlled precipitation processes, where universal dynamics of voids
growth is revealed. Estimations of main quantitative and statistical
characteristics of voids by using material parameters relevant to most of
alloys and steels give good agreement with experimental observations.Comment: 21 pages, 10 figure
Response of Merkel cell polyomavirus-positive Merkel cell carcinoma xenografts to a survivin inhibitor
Merkel cell carcinoma (MCC) is a neuroendocrine skin cancer associated with high mortality. Merkel cell polyomavirus (MCV), discovered in 2008, is associated with ∼80% of MCC. The MCV large tumor (LT) oncoprotein upregulates the cellular oncoprotein survivin through its conserved retinoblastoma protein-binding motif. We confirm here that YM155, a survivin suppressor, is cytotoxic to MCV-positive MCC cells in vitro at nanomolar levels. Mouse survival was significantly improved for NOD-Scid-Gamma mice treated with YM155 in a dose and duration dependent manner for 3 of 4 MCV-positive MCC xenografts. One MCV-positive MCC xenograft (MS-1) failed to significantly respond to YM155, which corresponds with in vitro dose-response activity. Combination treatment of YM155 with other chemotherapeutics resulted in additive but not synergistic cell killing of MCC cell lines in vitro. These results suggest that survivin targeting is a promising therapeutic approach for most but not all MCV-positive MCCs. © 2013 Dresang et al
High viral load of Merkel cell polyomavirus DNA sequences in Langerhans cell sarcoma tissues.
International audienceBACKGROUND: Langerhans cell (LC) sarcoma (LCS) is a high-grade neoplasm with overtly malignant cytologic features and an LC phenotype. We very recently suggested that LC behaves as a reservoir for common dermotropic Merkel cell polyomavirus (MCPyV) and determined the relationship between LC histiocytosis (LCH), which has an underlining oncogenic capacity, and MCPyV as a trigger for a reactive process rather than a neoplastic process. We propose LC to be a reservoir for MCPyV and hypothesize that some LCS subtypes may be related to the MCPyV agent. FINDINGS: We examined seven LCS tissues using multiplex quantitative PCR (Q-PCR) and immunohistochemistry with anti MCPyV large-T (LT) antigen antibody. High viral loads of MCPyV DNA sequences (viral load = relative levels of MCPyV) were detected (0.328-0.772 copies/cell (Merkel cell carcinoma (MCC) = 1.0)) using Q-PCR in 43% (3/7) tissues, but LT antigen expression was not observed (0/7). CONCLUSIONS: Frequent MCPyV-DNA amplification suggests that LCS in some patients may be related to MCPyV infection. Moreover, the higher viral load of LCS (median, 0.453 copies/cell) than low load of LCH (0.003, median of 12 cases) (P < 0.01) may suggest a virally induced tumorigenic process in some LCS. Although the absence of LT antigen expression may indicate a different role for MCPyV in this pathology, some subtypes of LCS may develop in the background of MCPyV-infected LC. To the best of our knowledge, this is the first report on the relationship between MCPyV and LCS. The recent discovery of MCPyV opened new therapeutic avenues for MCC. These data open novel possibilities for therapeutic interventions against LCS
Translation initiation and its deregulation during tumorigenesis
Regulation of protein synthesis at the level of translation initiation is fundamentally important for the control of cell proliferation under normal physiological conditions. Conversely, misregulation of protein synthesis is emerging as a major contributory factor in cancer development. Most bulk protein synthesis is initiated via recognition of the mRNA 5′ cap and subsequent recognition of the initiator AUG codon by a directional scanning mechanism. However, several key regulators of tumour development are translated by a cap-independent pathway. Here we review eukaryotic translation initiation, its regulation and the ways in which this regulation can break down during tumorigenesis
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