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In this Perspective article, we introduce a new framework for the global non-equilibrium thermodynamics of stationary states. This theory uses the spatial distributions of temperature, density, velocity, and other variables in stationary states as its input. It outputs the global state parameters to describe the system's energy exchange with the environment. The number of state parameters is determined solely by the type of substance in the system and external potentials, regardless of the number of boundary conditions, fluxes within the system, or its specific geometry. The theory offers a second law of non-equilibrium thermodynamics for stationary states, predicting the direction of spontaneous processes between them. When all macroscopic fluxes reach zero, the theory reduces to equilibrium thermodynamics. [ABSTRACT FROM AUTHOR]

We study the surface tension of electrolyte solutions at the air/water and oil/water interfaces. Employing field-theoretical methods and considering short-range interactions of anions with the surface, we expand the Helmholtz free energy to first order in a loop expansion and calculate the excess surface tension. Our approach is self-consistent and yields an analytical prediction that reunites the Onsager-Samaras pioneering result (which does not agree with experimental data), with the ionic specificity of the Hofmeister series. We obtain analytically the surface-tension dependence on the ionic strength, ionic size and ion-surface interaction, and show consequently that the Onsager-Samaras result is consistent with the one-loop correction beyond the mean-field result. Our theory fits well a wide range of concentrations for different salts using one fit parameter, reproducing the reverse Hofmeister series for anions at the air/water and oil/water interfaces. [ABSTRACT FROM AUTHOR]

Following the publication of Freund's work on entropic pressure (Freund L., Proc. Natl. Acad. Sci. U.S.A., 110 (2013) 2047), which states that the undulation pressure for a biomembrane confined between two parallel rigid walls decays linearly with wall separation (d), different contradictory views on the pressure law evolved; some supporting Helfrich's prediction that the entropic pressure scales as . Attempts were made to resolve this stark contradiction by distinct groups of researchers. In this work, using dissipative particle dynamics simulations it has been shown for the first time that the height fluctuations are suppressed by wall confinement. An analysis of the fluctuation spectrum reveals that the entropic loss manifests as a membrane tension for a membrane that conserves its local area, and this fact is confirmed by the rise in stresses with an increase in wall confinement. Furthermore, we theorize a pressure law, which interestingly is congruous with Freund's prediction that the entropic pressure scales as . [ABSTRACT FROM AUTHOR]

The passage of DNA through a nanopore can be effectively decomposed into two distinct phases, docking and actual translocation. In experiments each phase is characterized by a distinct current signature which allows the discrimination of the two events. However, at low voltages a clear distinction of the two phases is lost. By using numerical simulations we clarify how the current signature associated to the docking events depends on the applied voltage. The simulations show that at small voltage the DNA globule enhances the pore conductance due to an enrichment of charge carriers. At high voltage, the globule drains substantial charge carriers from the pore region, thereby reducing the overall conductance. The results provide a new interpretation to the experimental data on conductance and show how docking interferes with the translocation signal, of potential interest for sequencing applications. [ABSTRACT FROM AUTHOR]

Despite the fact that the magnitude of surface slip, which may occur for a liquid flowing past a solid wall, was quantified by different experimental techniques, the microscopic origin of this effect remains unclear. In the present article we present a neutron reflectivity study for a Newtonian liquid, hexadecane, in contact with solid walls at rest and under shear. In this system slip is not explained by a depleted liquid layer. [ABSTRACT FROM AUTHOR]