2,310 research outputs found

    Re-equilibration after quenches in athermal martensites:Conversion-delays for vapour to liquid domain-wall phases

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    Entropy barriers and ageing states appear in martensitic structural-transition models, slowly re-equilibrating after temperature quenches, under Monte Carlo dynamics. Concepts from protein folding and ageing harmonic oscillators turn out to be useful in understanding these nonequilibrium evolutions. We show how the athermal, non-activated delay time for seeded parent-phase austenite to convert to product-phase martensite, arises from an identified entropy barrier in Fourier space. In an ageing state of low Monte Carlo acceptances, the strain structure factor makes constant-energy searches for rare pathways, to enter a Brillouin zone `golf hole' enclosing negative energy states, and to suddenly release entropically trapped stresses. In this context, a stress-dependent effective temperature can be defined, that re-equilibrates to the quenched bath temperature.Comment: 11 pages, 12 figures. Under process with Phys. Rev. B (2015

    4-Keto-4,5,6,7-tetrahydrooxindoles & 1 -carboxymethylene-2-anilino-l-cyclohexen-6-ones with potential antiinflammatory activity

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    l-Aryl-4-oxo-4,5,6,7-tetrahydroindoles (1-16) have been synthesised by the condensation of cyclohexane-l,3-dione-2-acetic esters with anilines. Hydrolysis of 1-16 affords the corresponding acids( 17-32), bearing resemblance to the nonsteroidal antiinflammatory agent, diclofenac 38. Some members of both classes show antiinflammatory activity in the carragenin oedema test and analgesic activity in mouse writhing test, but are devoid of prostaglandin synthetase inhibiting property. Among these, 1-carboxymethylene-2-(4-trifluoromeihylanilino)-l-cyclohexen-6-one (20) has marginal activity in the chronic adjuvant arthritis model of inflammation

    Techniques for Evaluating the Fit of Removable and Fixed Prosthesis

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    The importance of an accurately fitting fixed prosthesis or a removable prosthesis is essential for the success of the restoration. Ill-fitting prosthesis may cause mechanical failures of the prosthesis, implant systems, or biologic complications of the surrounding tissue. There are several causes related to improper seating of the prosthesis. Some of which can be corrected and the others need to be repeated. Hence the clinician must carefully evaluate the adaptation of the prosthesis using the clinical techniques and combination of the available materials and evaluation methods to optimize the fit of prosthesis. This article reviews the various clinical methods that have been suggested for evaluating the fit of the fixed and removable prosthesis

    X - Ray Flares and Their Connection With Prompt Emission in GRBs

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    We use a wavelet technique to investigate the time variations in the light curves from a sample of GRBs detected by Fermi and Swift. We focus primarily on the behavior of the flaring region of Swift-XRT light curves in order to explore connections between variability time scales and pulse parameters (such as rise and decay times, widths, strengths, and separation distributions) and spectral lags. Tight correlations between some of these temporal features suggest a common origin for the production of X-ray flares and the prompt emission.Comment: 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 15 in eConf Proceedings C130414

    Forecasting Stock Time-Series using Data Approximation and Pattern Sequence Similarity

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    Time series analysis is the process of building a model using statistical techniques to represent characteristics of time series data. Processing and forecasting huge time series data is a challenging task. This paper presents Approximation and Prediction of Stock Time-series data (APST), which is a two step approach to predict the direction of change of stock price indices. First, performs data approximation by using the technique called Multilevel Segment Mean (MSM). In second phase, prediction is performed for the approximated data using Euclidian distance and Nearest-Neighbour technique. The computational cost of data approximation is O(n ni) and computational cost of prediction task is O(m |NN|). Thus, the accuracy and the time required for prediction in the proposed method is comparatively efficient than the existing Label Based Forecasting (LBF) method [1].Comment: 11 page

    Sensory organ like response determines the magnetism of zigzag-edged honeycomb nanoribbons

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    We present an analytical theory for the magnetic phase diagram for zigzag edge terminated honeycomb nanoribbons described by a Hubbard model with an interaction parameter U . We show that the edge magnetic moment varies as ln U and uncover its dependence on the width W of the ribbon. The physics of this owes its origin to the sensory organ like response of the nanoribbons, demonstrating that considerations beyond the usual Stoner-Landau theory are necessary to understand the magnetism of these systems. A first order magnetic transition from an anti-parallel orientation of the moments on opposite edges to a parallel orientation occurs upon doping with holes or electrons. The critical doping for this transition is shown to depend inversely on the width of the ribbon. Using variational Monte-Carlo calculations, we show that magnetism is robust to fluctuations. Additionally, we show that the magnetic phase diagram is generic to zigzag edge terminated nanostructures such as nanodots. Furthermore, we perform first principles modeling to show how such magnetic transitions can be realized in substituted graphene nanoribbons.Comment: 5 pages, 5 figure

    Gamma-Ray Bursts: Temporal Scales and the Bulk Lorentz Factor

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    For a sample of Swift and Fermi GRBs, we show that the minimum variability timescale and the spectral lag of the prompt emission is related to the bulk Lorentz factor in a complex manner: For small Γ\Gamma's, the variability timescale exhibits a shallow (plateau) region. For large Γ\Gamma's, the variability timescale declines steeply as a function of Γ\Gamma (δTΓ4.05±0.64\delta T\propto\Gamma^{-4.05\pm0.64}). Evidence is also presented for an intriguing correlation between the peak times, tp_p, of the afterglow emission and the prompt emission variability timescale.Comment: Accepted for publication in Ap

    The modulatory effect of septilin on cytotoxicity of cisplatin in a human breast adenocarcinoma cell line

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    Cisplatin (Csp) is a recurrently used chemotherapeutic drug but its use is inadequate due to undesirable adverse effects. In search of alternative medicine more attention has been given to phytochemicals. Septilin (Spt), a polyherbal drug and its therapeutic potential is huge but there is a scarcity of studies on its cytotoxic potential on cancer cells. The current study was designed to examine the effects of Spt in combination with Csp on human breast adenocarcinoma (MCF-7) and normal human breast epithelial (MCF-10A) cell lines. Cell viability for Spt treated cells was studied using MTT assay. IC50 value of Csp on MCF-7 cells was found to be 10 μg/mL at 24 h. This dose was further used to study the combined effects of Csp with Spt on MCF-7 and MCF-10A cell lines. Maximum cytotoxicity of Spt on MCF-7 cells was observed at Spt 5 μg/mL. The mechanism of Spt induced cytotoxicity was studied using apoptosis assay. Spt did not show any cytotoxic effects on MCF-10 A normal human breast epithelial cells, indicating Spt has no effect on normal cells. Our findings suggest that Spt can be used in combination with an anticancer drug Csp to increase its efficacy and/or to minimize its side effects on normal cells
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