We consider a model for ternary polymer mixtures with biand tri-functional monomers and solvent molecules embedded on a honeycomb lattice. We first show that the grand partition function of the model polymer mixture is equivalent to the partition function of an eight-vertex model on the same lattice. This equivalence transforms the model into an Ising model in a nonzero external magnetic field....

Sphingomyelin and cholesterol are membrane lipids that interact to form liquid-ordered phase believed to act as a platform for the organization of signaling proteins. We report analyses of synchrotron X-ray powder diffraction patterns recorded from aqueous dispersions of ternary mixtures of sphingomyelin and phosphatidylcholine from egg yolk and cholesterol to investigate how cholesterol distri...

In the weak-coupling limit, κ0 → ∞, the partition function of simplicial quantum gravity is dominated by an ensemble of triangulations with the ratio N0/ND close to the upper kinematic limit. For a combinatorial triangulation of the D–sphere this limit is 1/D. Defining an ensemble of maximal triangulations, i.e. triangulations that have the maximal possible number of vertices for a given volume...

Solid Phase Microextraction (SPME) uses a small volume of sorbent dispersed typically on the surface of small fibres, to isolate and concentrate analytes from sample matrix. After contact with sample, analytes are absorbed or adsorbed by the fibre phase (depending on the nature of the coating) until an equilibrium is reached in the system. The amount of an analyte extracted by the coating at eq...

In the framework of schematic hard spheres lattice models we discuss Edwards' Statistical Mechanics approach to granular media. As this approach appears to hold here to a very good approximation, by analytical calculations of Edwards' partition function at a mean field level we derive the system phase diagram and show that " jamming " corresponds to a phase transition from a " fluid " to a " gl...

We develop a new analytical equation of state for water based on the Song, Mason, and Ihm equation of state and Poole et al.’s simple model of the free energy of strong tetrahedral hydrogen bonds. Repulsive and attractive forces are modeled using a modification of the Weeks–Chandler– Anderson decomposition of the pair potential, with closed tetrahedral hydrogen bonds contributing both internal ...

Here we develop an explicitly covariant expression for the stationary phase approximation of a classical partition function based on geometric properties of the phase space. As an example of the utility of such an evaluation we show that in the case of the Hamiltonian ows generating conformal rescalings of the underlying geometry, the classical partition function is given exactly by the leading...

The two techniques aqueous two-phase partitioning and expanded bed adsorption that both are suitable for primary protein recovery were studied. Most of the work was focused on partition in aqueous two-phase systems and in particular on the possibility to effect the partition behaviour by fusion of short peptide tags or protein domains to the target protein. The partitioning of fusion proteins b...

Background and aims: A selective and sensitive high performance liquid chromatography-electrospray ionization mass spectrometry method has been established for determination of methotrexate in human plasma. Methods: Methotrexate was extracted from plasma with acetonitrile. The mobile phase consisted of acetonitrile-water-formic acid 74: 25: 1(v/v). Twenty...

Iran’s vast common natural gas resources and the necessity to extract and export it as Liquefied Natural Gas (LNG) to distances more than 3000Km opens a lucrative field for researchers to optimize LNG cycles. In this article heat integration in cryogenic cycles by determining interacycle partition temperature and optimizing refrigeration features like Subcooler, Presaturator, aftercooler, reboi...