Exogenous Vitamins K Exert Anti-Inflammatory Effects Dissociated from Their Role as Substrates for Synthesis of Endogenous MK-4 in Murine Macrophages Cell Line.

Vitamins K exert a range of activities that extend far beyond coagulation and include anti-inflammatory effects, but the mechanisms involved in anti-inflammatory action remain unclear. In the present study, we showed that various forms of exogenous vitamins-K1, K3, K2 (MK-4, MK-5, MK-6 and MK-7)-regulated a wide scope of inflammatory pathways in murine macrophages in vitro, including NOS-2, COX-2, cytokines and MMPs. Moreover, we demonstrated for the first time that macrophages are able to synthesise endogenous MK-4 on their own. Vitamins with shorter isoprenoid chains-K1, K3 and MK-5-exhibited stronger anti-inflammatory potential than vitamins with longer isoprenoid chains (MK-6 and MK-7) and simultaneously were preferably used as a substrate for MK-4 endogenous production. Most interesting, atorvastatin pretreatment inhibited endogenous MK-4 production but had no impact on the anti-inflammatory activity of vitamins K. In summary, our results demonstrate that macrophages are able to synthesise endogenous MK-4 using exogenous vitamins K, and statin inhibits this process. However, the anti-inflammatory effect of exogenous vitamins K was independent of endogenous MK-4 synthesis.

Continuous and discontinuous transitions between two types of capillary bridges on a beaded chain pulled out from a liquid.

Capillary bridges can be used for fabricating new materials and structures. Here, we describe theoretically and validate experimentally the mechanism of formation of capillary bridges during a process in which a beaded chain is being pulled out from a liquid with a planar surface. There are two types of capillary bridges present in this system, namely the sphere-planar liquid surface bridge initially formed between the spherical bead leaving the liquid bath and the initially planar liquid surface, and the sphere-sphere capillary bridge formed between neighbouring beads in the part of the chain above the liquid surface. During the process of pulling the chain out of the liquid, the sphere-planar liquid surface bridge transforms into the sphere-sphere bridge. We show that for monodisperse spherical beads comprising the chain, this transition can be either continuous or discontinuous. The transition is continuous when the diameter of the spherical beads is larger than the capillary length. Otherwise, the transition is discontinuous, likewise the capillary force acting on the chain.

Lateral critical Casimir force in two-dimensional inhomogeneous Ising strip. Exact results.

We consider two-dimensional Ising strip bounded by two planar, inhomogeneous walls. The inhomogeneity of each wall is modeled by a magnetic field acting on surface spins. It is equal to +h1 except for a group of N1 neighboring surface spins where it is equal to -h1. The inhomogeneities of the upper and lower wall are shifted with respect to each other by a lateral distance L. Using exact diagonalization of the transfer matrix, we study both the lateral and normal critical Casimir forces as well as magnetization profiles for different temperature regimes: below the wetting temperature, between the wetting and the critical temperature, and above the critical temperature. The lateral critical Casimir force acts in the direction opposite to the shift L, and the excess normal force is always attractive. Upon increasing the shift L we observe, depending on the temperature regime, three different scenarios of breaking of the capillary bridge of negative magnetization connecting the inhomogeneities of the walls across the strip. As long as there exists a capillary bridge in the system, the magnitude of the excess total critical Casimir force is almost constant, with its direction depending on L. By investigating the bridge morphologies we have found a relation between the point at which the bridge breaks and the inflection point of the force. We provide a simple argument that some of the properties reported here should also hold for different models of the strip with the same type of inhomogeneity.

Dynamics of a liquid film of arbitrary thickness perturbed by a nano-object.

We provide a theoretical description of the dynamics of a liquid film perturbed by a nano-object. Our analysis is based on the general dispersion relation for surface perturbations which is valid for films of arbitrary thickness. In the case of thin liquid films the lubrication approximation is retrieved. The relevant time scales are derived and related to the characteristic length scales present in the system. We show that the multi length-scale character of the interfacial deformation is reflected in a wide range of the time scales describing the dynamics of the liquid film. In the case of relaxation under the action of a time-independent perturbation the analytical approximations to the interface evolution are obtained in several time regimes. The case of a general time-dependent perturbation is studied within the point-force approximation which allows determination of the universal aspects of liquid film dynamics. This method is also used to describe the response of the liquid film to a periodic perturbation which simulates the dynamic mode of the tip of an atomic force microscope. It is shown that proper consideration of the thickness of the film leads to results which significantly differ from those obtained within the lubrication approximation even for relatively thin films.

Lateral critical Casimir force in 2D Ising strip with inhomogeneous walls.

We analyze the lateral critical Casimir force acting between two planar, chemically inhomogeneous walls confining an infinite 2D Ising strip of width M. The inhomogeneity of each of the walls has size N1; they are shifted by the distance L along the strip. Using the exact diagonalization of the transfer matrix, we calculate the lateral critical Casimir force and discuss its properties, in particular its scaling close to the 2D bulk critical point, as a function of temperature, surface magnetic field, and the geometric parameters M, N1, L. We determine the magnetization profiles which display the formation of the bridge joining the inhomogeneities on the walls and establish the relation between the characteristic properties of the lateral Casimir force and magnetization morphologies. We check numerically that breaking of the bridge is related to the inflection point of the lateral force.

Capillary-gravity waves on a liquid film of arbitrary depth: analysis of the wave resistance.

We discuss the wave resistance in the case of an externally perturbed viscous liquid film of arbitrary thickness. Emphasis is placed on the dependence of the wave resistance on the film thickness H, the length scale b characterizing the external perturbation, and its velocity V. In particular, the effectiveness of the mechanisms of capillary-gravity waves and the viscous dissipation localized in the vicinity of the perturbation are compared and discussed as functions of H and V. We show that, in general, the wave resistance is a nonmonotonous function of H with a maximum whose amplitude and position depend on b and V. In the case of small H the wave resistance depends on a parameter S proportional V/H(3). We find three different regimes of this parameter in which the wave resistance behaves like S(r) with the exponent r equal to 1, 1/3, and -1. These results are also obtained independently within the thin liquid film approximation. This allows us to assess the range of validity of the thin liquid film approximation in various cases, in particular its dependence on the perturbation length scale b.

Phase diagrams and solvation forces of a uniaxial ferromagnet in a slit--the double-parabola approach.

We obtain the phase diagrams of a uniaxial ferromagnet enclosed in a slit and analyse the properties of the solvation forces acting between the slit walls. Our analysis is based on the mean-field theory applied to the double-parabola Hamiltonian for a uniaxial ferromagnet in a slit, which allows us to derive several results in analytic form. In particular, the Kelvin law and the law describing the influence of the slit width on the position of the delocalization transition as compared to the wetting transition are derived and the corresponding critical exponent is evaluated. The influence of the thermodynamic state of the system on the properties of the solvation forces, in particular their discontinuous behaviour at coexistence lines, is discussed.

Casimir force induced by an imperfect Bose gas.

We present a study of the Casimir effect in an imperfect (mean-field) Bose gas contained between two infinite parallel plane walls. The derivation of the Casimir force follows from the calculation of the excess grand-canonical free energy density under periodic, Dirichlet, and Neumann boundary conditions with the use of the steepest descent method. In the one-phase region, the force decays exponentially fast when distance D between the walls tends to infinity. When the Bose-Einstein condensation point is approached, the decay length in the exponential law diverges with critical exponent ν(IMP) = 1, which differs from the perfect gas case where ν(P) = 1/2. In the two-phase region, the Casimir force is long range and decays following the power law D(-3), with the same amplitude as in the perfect gas.

Scaling of solvation force in two-dimensional Ising strips.

The solvation force for two-dimensional Ising strips is calculated via exact diagonalization of the transfer matrix in two cases: the symmetric case corresponds to identical surface fields and the antisymmetric case to exactly opposite surface fields. In the symmetric case the solvation force is always negative (attractive), while in the antisymmetric case the solvation force is positive (repulsive) at high temperatures and negative at low temperatures. It changes sign close to the critical wetting temperature characterizing the semi-infinite system. The properties of the solvation force are discussed, and the scaling function describing its dependence on temperature, surface field, and strip's width is proposed.