311 research outputs found

    Toward the use of similarity theory in two-phase choked flows

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    Comparison of two phase choked flows in normalized coordinates were made between pure components and available data using a reference fluid to compute the thermophysical properties. The results are favorable. Solution of the governing equations for two LNG mixtures show some possible similarities between the normalized choked flows of the two mixtures, but the departures from the pure component loci are significant

    Tumour necrosis factor-α up-regulates macrophage migration inhibitory factor expression in endometrial stromal cells via the nuclear transcription factor NF-κB

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    BACKGROUND: A series of controlled changes including proliferation, secretion and menstrual shedding occur in the human endometrium during every normal menstrual cycle. Macrophage migration inhibitory factor (MIF), a multifunctional cytokine with numerous proinflammatory, immunomodulatory and angiogenic properties, appears to be expressed in the human endometrium and to follow a regulated cycle phase-dependent expression, but the mechanisms underlying endometrial MIF expression remain to be fully elucidated. METHODS AND RESULTS: Results from enzyme-linked immunosorbent assay (ELISA) demonstrated a significant dose- and time-dependent increase in MIF secretion by human endometrial cells in response to tumour necrosis factor-alpha (TNF-α) (0.1-100 ng/ml). This increase was also observed at the mRNA level as shown by reverse transcription (RT)-PCR. Curcumin (10−8 mol/l), a known nuclear factor (NF)-κB inhibitor, inhibited the TNF-α-induced pIκB phosphorylation as shown by western blotting, NF-κB translocation into the nucleus as shown by electrophoretic mobility shift assay, and MIF synthesis and secretion as measured by ELISA and RT-PCR. The expression of a dominant-negative NF-κB inhibitor (IκB) significantly decreased the TNF-α-induced MIF promoter activity as analysed by transient cell transfection. CONCLUSIONS: These results indicate clearly that TNF-α up-regulates the expression of MIF in endometrial stromal cells. This took place possibly through NF-κB activation, and may play an important role in the physiology of the human endometriu

    Master crossover functions for the one-component fluid "subclass"

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    Introducing three well-defined dimensionless numbers, we establish the link between the scale dilatation method able to estimate master (i.e. unique) singular behaviors of the one-component fluid "subclass" and the universal crossover functions recently estimated [Garrabos and Bervillier, Phys. Rev. E 74, 021113 (2006)] from the bounded results of the massive renormalization scheme applied to the..

    Critical Viscosity Exponent for Fluids: What Happend to the Higher Loops

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    We arrange the loopwise perturbation theory for the critical viscosity exponent xηx_{\eta}, which happens to be very small, as a power series in xηx_{\eta} itself and argue that the effect of loops beyond two is negligible. We claim that the critical viscosity exponent should be very closely approximated by xη=815π2(1+83π2)0.0685x_{\eta}=\frac{8}{15 \pi^2}(1+\frac{8}{3 \pi^2})\simeq 0.0685.Comment: 9 pages and 3 figure

    Existence of a critical point in the phase diagram of the ideal relativistic neutral Bose gas

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    We explore the phase transitions of the ideal relativistic neutral Bose gas confined in a cubic box, without assuming the thermodynamic limit nor continuous approximation. While the corresponding non-relativistic canonical partition function is essentially a one-variable function depending on a particular combination of temperature and volume, the relativistic canonical partition function is genuinely a two-variable function of them. Based on an exact expression of the canonical partition function, we performed numerical computations for up to hundred thousand particles. We report that if the number of particles is equal to or greater than a critical value, which amounts to 7616, the ideal relativistic neutral Bose gas features a spinodal curve with a critical point. This enables us to depict the phase diagram of the ideal Bose gas. The consequent phase transition is first-order below the critical pressure or second-order at the critical pressure. The exponents corresponding to the singularities are 1/2 and 2/3 respectively. We also verify the recently observed `Widom line' in the supercritical region.Comment: 1+25 pages, 6 B/W figures: Comment on the Widom line added. Minor improvement. Version to appear in `New Journal of Physics

    Thermodynamic characteristics of the classical n-vector magnetic model in three dimensions

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    The method of calculating the free energy and thermodynamic characteristics of the classical n-vector three-dimensional (3D) magnetic model at the microscopic level without any adjustable parameters is proposed. Mathematical description is perfomed using the collective variables (CV) method in the framework of the ρ4\rho^4 model approximation. The exponentially decreasing function of the distance between the particles situated at the N sites of a simple cubic lattice is used as the interaction potential. Explicit and rigorous analytical expressions for entropy,internal energy, specific heat near the phase transition point as functions of the temperature are obtained. The dependence of the amplitudes of the thermodynamic characteristics of the system for T>TcT>T_c and T<TcT<T_c on the microscopic parameters of the interaction potential are studied for the cases n=1,2,3n=1,2,3 and nn\to\infty. The obtained results provide the basis for accurate analysis of the critical behaviour in three dimensions including the nonuniversal characteristics of the system.Comment: 25 pages, 5 figure

    Free Energy Minimizers for a Two--Species Model with Segregation and Liquid-Vapor Transition

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    We study the coexistence of phases in a two--species model whose free energy is given by the scaling limit of a system with long range interactions (Kac potentials) which are attractive between particles of the same species and repulsive between different species.Comment: 32 pages, 1 fig, plain tex, typeset twic

    Communication: Analytic continuation of the virial series through the critical point using parametric approximants

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    The mathematical structure imposed by the thermodynamic critical point motivates an approximant that synthesizes two theoretically sound equations of state: the parametric and the virial. The former is constructed to describe the critical region, incorporating all scaling laws; the latter is an expansion about zero density, developed from molecular considerations. The approximant is shown to yield an equation of state capable of accurately describing properties over a large portion of the thermodynamic parameter space, far greater than that covered by each treatment alone
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