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We construct a generalization of Widom’s model of microemulsions which permits the contact of polar and apolar material. This is necessary to explain the behavior of certain short chain amphiphilic systems. The same interactions have previously been proposed by Robledo, but the partition function which he derived from these interactions and discussed in detail in his paper (a partition function of a spin 1 Ising system) does not quite represent these interactions. We arrive at a spin 3/2 Ising model with nearest neighbor interactions. Robledo’s spin 1 form is recovered as an approximation whose range of validity is discussed. We particularly investigate the limit towards Widom’s model, the progression of Winsor microemulsion, and the question of retrograde solubility in the binary water–amphiphile subsystem, which has been advocated by Robledo. [ABSTRACT FROM AUTHOR]

We extend Widom’s Ising-like model of microemulsions on a simple cubic lattice by a new term which accounts for the Gaussian curvature energy of the oil–water interfaces. The new term distinguishes between different topologies of the interfaces and plays an important role in determining the microstructure of microemulsions on a scale larger or comparable to the persistence length provided that the microemulsion is dominated at all by curvature energies. We also speculate on its possible role for the breakdown of curvature energies in microemulsions. [ABSTRACT FROM AUTHOR]

We extend a previous calculation and comparison with experiment of the shape of the three-phase regime, of a ternary mixture of water, oil, and tenside, in the space of concentrations and temperature x, y, τ into the neighborhood of the three-phase regime. Apart from the two- and one-phase boundaries, we determine the behavior of the intensity of scattered light and the interfacial energies. The agreement with experimental data is reasonable. [ABSTRACT FROM AUTHOR]

Using a simple Landau free energy we determine the shape of the three-phase regime of a ternary mixture of water, oil, and tenside (microemulsion) in the space of concentrations and temperature x, y, τ. The boundaries at x=0 (equal water and oil) and y=1 (fixed tenside) are in excellent agreement with recent data of Kahlweit et al. and Shinoda et al. We also find satisfactory agreement for the temperature behavior of fluctuation phenomena such as the intensity of scattered light and the interfacial tensions. [ABSTRACT FROM AUTHOR]

Free and weakly interacting particles are described by a second-quantized nonlinear Schrödinger equation, or relativistic versions of it. They describe Gaussian random walks with collisions. By contrast, the fields of strongly interacting particles are governed by effective actions, whose extremum yields fractional field equations. Their particle orbits perform universal Lévy walks with heavy tails, in which rare events are much more frequent than in Gaussian random walks. Such rare events are observed in exceptionally strong windgusts, monster or rogue waves, earthquakes, and financial crashes. While earthquakes may destroy entire cities, the latter have the potential of devastating entire economies. [ABSTRACT FROM AUTHOR]

We show that a triangular lattice consisting of dipolar molecules pointing orthogonally to the plane undergoes a first-order defect melting transition. [ABSTRACT FROM AUTHOR]

Chronic inflammation increases the risk of cancer and many cancers, including prostate cancer, arise at sites of chronic inflammation. Inducible nitric oxide synthase (iNOS) is an enzyme dominantly expressed during inflammatory reactions. Although synthesis of high amounts of nitric oxide (NO) by iNOS has been demonstrated in pathophysiological processes, such as acute or chronic inflammation, autoimmune diseases or tumorigenesis, the role of iNOS activity in most of these diseases is poorly understood. Analysing prostate cancer biopsies by immunohistochemistry we found iNOS protein expression in tumor cells strongly paralleled by nitrotyrosine suggesting that iNOS is fully active. In vitro, NO inhibits androgen receptor-dependent promoter activity and prostate specific antigen production as well as DNA-binding activity of the androgen receptor (AR) in a concentration-dependent manner. Inhibition of the activity of androgen receptor-dependent reporter constructs is neither owing to diminished AR protein levels nor owing to an inhibition of its nuclear import. In addition, NO inhibits the proliferation of androgen receptor-positive prostate cancer cells significantly more efficiently than proliferation of androgen receptor-negative prostate cancer cells. In summary, our findings suggest that intratumoral iNOS activity favors development of prostate cancer cells that are able to proliferate androgen receptor-independently, thereby promoting prostate tumor progression.Oncogene (2007) 26, 1875–1884. doi:10.1038/sj.onc.1209984; published online 18 September 2006 [ABSTRACT FROM AUTHOR]

The partition function of a quantum statistical system in flat space can always be written as an integral over a classical Boltzmann factor exp[-βV[sup eff cl](x[sub 0])], where V[sup eff cl](x[sub 0]) is the so-called effective classical potential containing the effects of all quantum fluctuations. The variable of integration is the temporal path average [formula]. We show how to generalize this concept to paths q[sup μ](τ) in curved space with metric g[sub μν](q), and calculate perturbatively the high-temperature expansion of V[sup eff cl](q[sub 0]). The requirement of independence under coordinate transformations q[sup μ](τ)→ q′[sup μ](τ) introduces subtleties in the definition and treatment of the path average [formula], and covariance is achieved only with the help of a suitable Faddeev–Popov procedure. [ABSTRACT FROM AUTHOR]

Using variational perturbation theory, we calculate the shift in the critical temperature T[sub c] up to five loops to lowest order in the scattering length a and find [formula], where n is the particle density. Our result is slightly lower than the latest Monte Carlo result (1.32±0.02) an[sup 1/3]. [ABSTRACT FROM AUTHOR]

From a forward-backward path integral, we derive a master equation for the emission and absorption of gravitons by a massive quantum object in a heat bath of gravitons. Such an equation could describe the collapse phenomena of dense stars. We also present a useful approximate Langevin equation for such a system. [ABSTRACT FROM AUTHOR]

We show that the requirement of coordinate invariance of perturbatively defined quantum-mechanical path integrals in curved space leads to an extension of the theory of distributions by specifying unique rules for integrating products of distributions. The rules are derived by using equations of motion and partial integration, while keeping track of certain minimal features stemming from the unique definition of all singular integrals in 1 - ∈ dimensions. Our rules guarantee complete agreement with much more cumbersome calculations in 1 - ∈ dimensions where the limit ∈ → 0 is taken at the end. In contrast to our previous papers where we solved the same problem for an infinite time interval or zero temperature, we consider here the more involved case of finite-time or temperature amplitudes. [ABSTRACT FROM AUTHOR]

We set up a forward - backward path integral for a point particle in a bath of photons to derive a master equation for the density matrix which describes electromagnetic dissipation and decoherence. We also derive the associated Langevin equation. As an application, we recalculate the Wigner-Weisskopf formula for the natural line width of an atomic state at zero temperature and find, in addition, the temperature broadening caused by the decoherence term. Our master equation also yields the correct Lamb shift of atomic levels. The two equations may have applications to dilute interstellar gases or to few-particle systems in cavities. [ABSTRACT FROM AUTHOR]

In perturbative calculations of quantum-mechanical path integrals in curvilinear coordinates, one encounters Feynman diagrams involving multiple temporal integrals over products of distributions which are mathematically undefined. In addition, there are terms proportional to powers of Dirac $ \delta $-functions at the origin coming from the measure of path integration. We derive simple rules for dealing with such singular terms from the natural requirement of coordinate independence of the path integrals. [ABSTRACT FROM AUTHOR]

A stack of tensionless membranes with nonlinear curvature energy and vertical harmonic interaction is studied. At low temperatures, the system forms a lamellar phase. At a critical temperature, the stack disorders vertically in a melting-like transition. [ABSTRACT FROM AUTHOR]

We set up a field theoretical model based on Abelian Chern-Simons field theories to describe the topological entanglement of two polymers. The topological states of the system are distinguished using the link invariant of Gauss. The second topological moment of the two polymers , where m is the linking number, is exactly computed by field theoretical methods. The result is applied to estimate approximatively the mean square average of the linking number of a polymer P1 in a dilute solution with other polymers. [ABSTRACT FROM AUTHOR]

We argue that compatibility with elementary particle physics requires gravitational theories with torsion to be unable to distinguish between orbital angular momentum and spin. An important consequence of this principle is that spinless particles must move along autoparallel trajectories, not along geodesics. [ABSTRACT FROM AUTHOR]

Multiple fixation techniques have been developed for distal interphalangeal (DIP) joint arthrodesis. Delayed and nonunion rates varying from 0% to 20% have been reported. The senior author has refined a technique for DIP joint arthrodesis by using an intramedullary Kirschner wire and an interosseous wire for fusion of the DIP joint and interphalangeal (IP) joint of the thumb. In 24 joint arthrodeses in 19 patients, the nonunion rate was 4%, and the minor complication rate was 12%. The advantages of this technique include the absence of protruding hardware that would necessitate removal; consistency in achieving osteosynthesis, with a low nonunion rate; and technical simplicity. [ABSTRACT FROM AUTHOR]

We present a simpler and more powerful versionof the recently-discovered action principle for themotion of a spinless point particle in spacetimes withcurvature and torsion. The surprising feature of the new principle is that an action involving only the metric can produce an equation of motion witha torsion force, thus changing geodesics toautoparallels. This additional torsion force arises from a noncommutativity of variations with parameter derivatives of the paths due to the closure failure ofparallelograms in the presence of torsion. [ABSTRACT FROM AUTHOR]

We point out a possible mechanism by which smooth surfaces can become spiky as the constant of curvature stiffness falls below a certain critical value. This happens either in a single first-order transition, or in a sequence of two Kosterlitz-Thouless-like transitions. There may also be additional phases in which the spikes form a hexagonal solid-like array or a disordered liquid-like structure. Our discussion suggests that there exist smooth strings between quarks. [ABSTRACT FROM AUTHOR]

Discusses a technique for calculating functional determinants of second-order differential operators from Wronski Green functions. Computation of the periodic and antiperiodic boundary conditions without the knowledge of spectral properties; Derivation of formula for a harmonic oscillator with an arbitrary time-dependent frequency.

Objective and Design: ABT-299 is a prodrug that is converted by serum esterase to a potent platelet activating factor (PAF) antagonist (A-85783). In order to evaluate the pharmacological activity of this antagonist in man the effect of ABT-299 given to healthy volunteers on ex vivo PAF-induced β-thromboglobulin (β-TG) release in blood was assessed.¶ Subjects: 37 healthy male volunteers, age 18 to 40 (mean age of 23.6 years) and free of medication, participated in the study.¶ Treatment: Subjects were administered intravenously 0.8 mg, 2 mg, or 70 mg doses of ABT-299 (6–7 subjects per group) or placebo (9 subjects, pooled).¶ Methods: Peripheral blood taken over 12 h after dosing was used for ex vivo β-TG release and, in the case of the 70 mg dose, measurement of plasma drug concentration. Data were compared by Student's t-test.¶ Results: All three doses produced highly significant inhibition (p <0.005 compared to predose values) of PAF-induced β-TG release (units/ml plasma±SEM) 12 h after drug administration (54±14 vs. 405±51, n=8; 79±23 vs. 480±127, n=7; 21±10 vs. 327±72, n=6, respectively) whereas there was no significant difference in β-TG release in the placebo group (449±90 vs. 307±49, n=9). Inhibition was associated with the rapid appearance in plasma of A-85783 and the pyridine N-oxide metabolite of A-85783. Within 2 h, the plasma concentration of the metabolite exceeded that of the parent drug. Both the parent drug and the metabolite exhibited potent in vitro inhibition of PAF-induced β-TG release (A2 values of 4 and 1 nM respectively).¶ Conclusions: These studies are the first to illustrate the utility of the β-TG release assay for assessing ex vivo activity of PAF antagonists. These studies also demonstrate that the administration of ABT-299 to man results in potent, long lasting inhibition of PAF-mediated platelet activation, due in part to the pyridine- N-oxide metabolite, and support the potential therapeutic utility of this prodrug in treating PAF-mediated diseases. [ABSTRACT FROM AUTHOR]

In linear elasticity, the interaction energy between defects depends only on the total defect tensor and not on the particular composition in terms of the 6 + 6 components of the dislocation and disclination densities α( x) and θ( x), respectively. In momentum space, this energy is We show that higher gradients in the elastic energy give the additional defect energy where α ≡ (δ - ∂∂/∂)α. This removes the degeneracy for all 6 + 6 components of α and τ. The elastic constants are defined in the text. [ABSTRACT FROM AUTHOR]

We prove that a grand-canonical ensemble of random loops without spikes (i.e. without immediate backtrackcrs) obey a free disorder field theory with a mass parameter, on a simple cubic lattice, m = exp [ε/ T] − 2 D + (2 D − 1) exp [− ε/ T], where ε is the energy per link and D the spatial dimension. Thus the lines proliferate at a temperature T = ε/log(2 D−1) as one might naively expect. [ABSTRACT FROM AUTHOR]

We point out that the U lattice gauge theory and the recently developed theory of defect melting are closely related. They differ mainly by the positions of the « daggers » in the plaquette energy, i.e. U ( x) U ( x + i) U ( x + j) U ( x) is replaced by U ( x) U ( x + i) U ( x + j) U ( x). As a consequence, both theories have essentially the same mean-field approximation with a first-order transition at that level. In the gauge theory, this result is wrong and modified completely by fluctuations. Melting, on the other hand, is a first-order transition such that the mean-field result is in qualitative agreement with experiment. [ABSTRACT FROM AUTHOR]

We demonstrate that within our gauge theory of defects and stresses in three dimensions, disclinations play a crucial role in making the melting transition of first order. [ABSTRACT FROM AUTHOR]

We transform the Abelian Higgs model in three dimensions ( i.e. the Grinzburg-Landau theory) to a disorder field theory. The new fields describe the grand canonical ensemble of vortex lines in the superconductor and take a nonzero expectation in the normal state (signalizing their proliferation). The disorder theory allows for a simple determination of the tricritical point where the second-order phase transition changes to first. This happens for a Grinzburg-Landau parameter (= ratio of penetration depth to coherence length) K 0.8/√2. [ABSTRACT FROM AUTHOR]

We explicitly perform the infinitely many integrations in the path integral of an arbitrary time-dependent quantum-mechanical fluctuation problem whose Schrödinger equation is solvable. [ABSTRACT FROM AUTHOR]

We argue that local Higgs fields may correspond neither to pointlike particles nor to bound states of some more fundamental objects. Rather, they arise naturally in pure gauge theories as a convenient technical device for parametrizing line-like disorder. [ABSTRACT FROM AUTHOR]