We present a methodology to characterize a continuum-scale model of transport in porousmedia on the basis of pore-scale distributions of velocities computed in three-dimensional pore-space images. The methodology is tested against pore-scale simulations of flow and transport for a bead pack and a sandstone sample. We employ a double-continuum approach to describe transport inmobile and immobile...

OBJECTIVE This study investigates the effects of Nd:YAG laser irradiation combined with different irrigation protocols on the marginal seal of root fillings. BACKGROUND DATA Limited information exists regarding the effects of morphologic changes to root canal (RC) walls after Nd:YAG laser irradiation after smear-layer removal with EDTA on the sealing ability of root fillings. METHODS The 75...

To heal tissue defects, cells have to bridge gaps and generate new extracellular matrix (ECM). Macroporous scaffolds are frequently used to support the process of defect filling and thus foster tissue regeneration. Such biomaterials contain micro-voids (pores) that the cells fill with their own ECM over time. There is only limited knowledge on how pore geometry influences cell organization and ...

Spreading of a conservative solute in potential flow in a helical porous medium is dominated by the radial velocity distribution within the domain. Higher velocities at the inside of the helix compared to the outside leads to spreading that is balanced by transverse pore-scale dispersion. The angular moments of the concentration distribution exhibit the typical behavior of Taylor-Aris dispersio...

The mechanism of reversible electric breakdown of lipid membranes is studied. The following stages of the process of pore development are substantiated. Hydrophobic pores are formed in the lipid bilayer by spontaneous fluctuations. If these water-filled defects extend to a radius of 0.3 to 0.5 nm, a hydrophilic pore is formed by reorientation of the lipid molecules. This process is favoured by ...

The reconstruction of porous media is of great interest in a wide variety of fields, including earth science and engineering, biology, and medicine. To predict multiphase flow through geologically realistic porous media it is necessary to have a threedimensional (3D) representation of the pore space. Multiple-point statistics were used, based on two-dimensional (2D) thinsections as training ima...

A combined scanning electrochemical-atomic force microscope (SECM-AFM) has been used to probe the diffusional transport of target electroactive solutes in isolated nanopores of a track-etched membrane. A polycarbonate membrane (100-nm-diam pore size) hydrated with an electrolyte solution, containing a redox-active probe molecule, such as IrCl6(3-) or Fe(phen)3(2+), functions as the model membra...

The general theory for small dynamic motion superimposed upon large static deformation, or acoustoelasticity, is developed for isotropic fluid-filled poroelastic solids. Formulas are obtained for the change in acoustic wave speeds for arbitrary loading, both on the frame and the pore fluid. Specific experiments are proposed to find the complete set of third-order elastic moduli for an isotropic...

Ion channels catalyze ionic permeation across membranes via water-filled pores. To understand how changes in intracellular magnesium concentration regulate the influx of Mg2+ into cells, we examine early events in the relaxation of Mg2+ channel CorA toward its open state using massively-repeated molecular dynamics simulations conducted either with or without regulatory ions. The pore of CorA co...

The concept is easy to understand: A membrane with a single pore of appropriate size (diameter comparable to that of the molecule to detect) separates the two halves of an electrochemical cell. The cell is filled with an electrolyte, and a voltage is applied across the membrane. In the absence of any biomolecules in the solution, a steady flow of ions is measured as a constant current. As soon ...