Failure to downregulate the BAF53a subunit of the SWI/SNF chromatin remodeling complex contributes to the differentiation block in rhabdomyosarcoma

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Flame propagation in random media

We introduce a phase-field model to describe the dynamics of a self-sustaining propagating combustion front within a medium of randomly distributed reactants. Numerical simulations of this model show that a flame front exists for reactant concentration $c > c^* > 0$, while its vanishing at $c^*$ is consistent with mean-field percolation theory. For $c > c^*$, we find that the interface associated with the diffuse combustion zone exhibits kinetic roughening characteristic of the Kardar-Parisi-Zhang equation.Comment: 4, LR541

Formulation and Evaluation of Pulsatile Drug Delivery System of Zafirlukast

 In the current scenario of pharmaceutical research much attention has been focused on patients health in terms of therapeutic efficacy and economical standards (price factor).The formulation design consist of core tablets designed by direct compression method. Core tablets were coated with an naturally occurring swelling agent (carbopol & Karaya gum). Evaluation studies were performed for prepared pulsatile tablets hardness. In in vitro release profile of 6 hours study in first 5 hours it shows minimum drug release and at the end of six hours rapid and transient release was observed. Stability studies proved that coating of tablets seems to decrease the effect of temperature and moisture on degradation of Zafirlukast. The pulsatile release has been achieved from tablet over a 7-8 hour period. &nbsp

Dynamics of driven interfaces near isotropic percolation transition

We consider the dynamics and kinetic roughening of interfaces embedded in uniformly random media near percolation treshold. In particular, we study simple discrete ``forest fire'' lattice models through Monte Carlo simulations in two and three spatial dimensions. An interface generated in the models is found to display complex behavior. Away from the percolation transition, the interface is self-affine with asymptotic dynamics consistent with the Kardar-Parisi-Zhang universality class. However, in the vicinity of the percolation transition, there is a different behavior at earlier times. By scaling arguments we show that the global scaling exponents associated with the kinetic roughening of the interface can be obtained from the properties of the underlying percolation cluster. Our numerical results are in good agreement with theory. However, we demonstrate that at the depinning transition, the interface as defined in the models is no longer self-affine. Finally, we compare these results to those obtained from a more realistic reaction-diffusion model of slow combustion.Comment: 7 pages, 9 figures, to appear in Phys. Rev. E (1998

Scaling, Propagation, and Kinetic Roughening of Flame Fronts in Random Media

We introduce a model of two coupled reaction-diffusion equations to describe the dynamics and propagation of flame fronts in random media. The model incorporates heat diffusion, its dissipation, and its production through coupling to the background reactant density. We first show analytically and numerically that there is a finite critical value of the background density, below which the front associated with the temperature field stops propagating. The critical exponents associated with this transition are shown to be consistent with mean field theory of percolation. Second, we study the kinetic roughening associated with a moving planar flame front above the critical density. By numerically calculating the time dependent width and equal time height correlation function of the front, we demonstrate that the roughening process belongs to the universality class of the Kardar-Parisi-Zhang interface equation. Finally, we show how this interface equation can be analytically derived from our model in the limit of almost uniform background density.Comment: Standard LaTeX, no figures, 29 pages; (to appear in J. Stat. Phys. vol.81, 1995). Complete file available at http://www.physics.helsinki.fi/tft/tft.html or anonymous ftp at ftp://rock.helsinki.fi/pub/preprints/tft

Anomalous Sliding Friction and Peak Effect near the Flux Lattice Melting Transition

Recent experiments have revealed a giant "peak effect" in ultrapure high $T_c$ superconductors. Moreover, the new data show that the peak effect coincides exactly with the melting transition of the underlying flux lattice. In this work, we show using dynamical scaling arguments that the friction due to the pinning centers acting on the flux lattice develops a singularity near a continuous phase transition and can diverge for many systems. The magnitude of the nonlinear sliding friction of the flux lattice scales with this atomistic friction. Thus, the nonlinear conductance should diverge for a true continuous transition in the flux lattice or peak at a weakly first order transition or for systems of finite size.Comment: 4 pages, to appear in Phys. Rev.

Marginal Pinning of Quenched Random Polymers

An elastic string embedded in 3D space and subject to a short-range correlated random potential exhibits marginal pinning at high temperatures, with the pinning length $L_c(T)$ becoming exponentially sensitive to temperature. Using a functional renormalization group (FRG) approach we find $L_c(T) \propto \exp[(32/\pi)(T/T_{\rm dp})^3]$, with $T_{\rm dp}$ the depinning temperature. A slow decay of disorder correlations as it appears in the problem of flux line pinning in superconductors modifies this result, $\ln L_c(T)\propto T^{3/2}$.Comment: 4 pages, RevTeX, 1 figure inserte

Numerical Studies of the Two Dimensional XY Model with Symmetry Breaking Fields

We present results of numerical studies of the two dimensional XY model with four and eight fold symmetry breaking fields. This model has recently been shown to describe hydrogen induced reconstruction on the W(100) surface. Based on mean-field and renormalization group arguments,we first show how the interplay between the anisotropy fields can give rise to different phase transitions in the model. When the fields are compatible with each other there is a continuous phase transition when the fourth order field is varied from negative to positive values. This transition becomes discontinuous at low temperatures. These two regimes are separated by a multicritical point. In the case of competing four and eight fold fields, the first order transition at low temperatures opens up into two Ising transitions. We then use numerical methods to accurately locate the position of the multicritical point, and to verify the nature of the transitions. The different techniques used include Monte Carlo histogram methods combined with finite size scaling analysis, the real space Monte Carlo Renormalization Group method, and the Monte Carlo Transfer Matrix method. Our numerical results are in good agreement with the theoretical arguments.Comment: 29 pages, HU-TFT-94-36, to appear in Phys. Rev. B, Vol 50, November 1, 1994. A LaTeX file with no figure

Using stable isotopes to assess surface water source dynamics and hydrological connectivity in a high-latitude wetland and permafrost influenced landscape

The research has been supported by the NERC/JPI SIWA project (NE/M019896/1); grant issued in accordance with Resolution of the Government of the Russian Federation No. 220 dated 9 April 2010, under Agreement No. 14.B25.31.0001 with Ministry of Education and Science of the Russian Federation dated 24 June 2013 (BIO-GEO-CLIM); grant RFBR No 17-05-00-348a; grant FCP “Kolmogorov” 14.587.21.0036, grant RNF No 15-17-1009, and grant RFBR No 17-55-16008. Stable water isotope data are available in the Natural Environment Research Council (NERC) Environmental Information Data Centre (EIDC) data repository (title: “Stable water isotopes in Western Siberian inland waters”, permanent identifier: https://doi.org/10.5285/ca17e364-638d-4949-befb-b18b3770aec6). We would like to acknowledge the Arctic-GRO and IAEA for their publicly available databases providing supporting data for our analyses. Stream flow data at Nikolskoe was provided by Sergey Vorobiev. Liliya Kovaleva is acknowledged for the artwork in Figure 9. We would like to thank the two anonymous reviewers and the handling editors for their constructive comments that improved the manuscript.Peer reviewedPublisher PD