We propose an efficient simulation algorithm based on the dissipative particle dynamics (DPD) method for studying electrohydrodynamic phenomena in electrolyte fluids. The fluid flow is mimicked with DPD particles while the evolution of the concentration of the ionic species is described using Brownian pseudo particles. The method is designed especially for systems with high salt concentrations, as explicit treatment of the salt ions becomes computationally expensive. For illustration, we apply the method to electro-osmotic flow over patterned, superhydrophobic surfaces. The results are in good agreement with recent theoretical predictions.

Binary mixtures (A, B) of colloidal particles of different sizes in two dimensions may form crystals with square lattice structure (the A-particles occupying the white sites and the B-particles the black sites of a checkerboard). Confining such a system by two parallel 'walls' a distance D apart, long-range order in the direction parallel to the walls is stabilized by 'corrugated walls' that are commensurate with the lattice structure but destabilized by structureless 'hard walls', even if there is no misfit between the strip width D and the crystal lattice spacing. The crossover to quasi-one-dimensional behavior is studied by Monte Carlo simulations, analyzing Lindemann parameters and displacement correlation functions. When D is reduced and thus a misfit created, the stress in the crystal increases up to a critical value, at which the stress jumps to much smaller values due to the formation of an (almost periodic) crack pattern. These cracks typically have a width of several particle diameters, and are mostly disordered, although sometimes small domains with hexagonal order can be identified. At very large misfits, glass-like structures appear. We discuss various methods to characterize order and disorder in such systems.

The presence of an unusual innervation to the long head of the triceps brachii muscle, different as described in anatomical textbooks, may have clinical importance. The aim of this cadaveric study is to explore a possible contribution of the axillary nerve to the motor innervation of the long head of the triceps in a Puerto Rican population. We dissected the posterior cord of the brachial plexus in a supine position in embalmed cadavers, and the path of axillary nerve was followed to the quadrangular space. In a prone position, the posterior attachment of the deltoid muscle was cut to expose the long head of the triceps and its relation with the axillary nerve. After the dissection was carried out, many photographs were taken. The objective of this study was to clarify the motor innervation of the long head of the triceps brachii muscle because it has not been fully elucidated. The majority of anatomical textbooks state that the motor branch of the long head of the triceps brachii arises from the radial nerve. In our study, we found some specimens where the axillary nerve was innervating the long head of the triceps. It is very important to be aware about the presence of this variation in case the motor branch of the triceps muscle is used as a donor for nerve transfer. Recognizing this variation may also be important in radial nerve pathologies. In this clinical setting, muscle wasting would presumably be absent in the area innervated by the axillary nerve.