A 2D finite element model for shear wave propagation in biological soft tissues: Application to magnetic resonance elastography.

Dynamic elastography is a virtual palpation tool that aims at investigating the mechanical response of biological soft tissues in vivo. The objective of this study is to develop a finite element model (FEM) with low computational cost for reproducing realistically wave propagation for magnetic resonance elastography in heterogeneous soft tissues. Based on the first-order shear deformation theory for moderately thick structures, this model is developed and validated through comparison with analytical formulations of wave propagating in heterogeneous, viscoelastic infinite medium.

An automatic differentiation-based gradient method for inversion of the shear wave equation in magnetic resonance elastography: specific application in fibrous soft tissues.

Quantitative and accurate measurement of in vivo mechanical properties using dynamic elastography has been the scope of many research efforts over the past two decades. Most of the shear-wave-based inverse approaches for magnetic resonance elastography (MRE) make the assumption of isotropic viscoelasticity. In this paper, we propose a quantitative gradient method for inversion of the shear wave equation in anisotropic media derived from a full waveform description using analytical viscoelastic Green formalism and automatic differentiation.

Phase diagram of complex fluids using an efficient integral equation method.

We present an adaptive technique for the determination of the phase diagram of fluids within the integral equation theory. It enables an efficient and accurate systematic mapping of the thermodynamic space in order to construct the binodal and spinodal lines. Results are obtained with the thermodynamically consistent integral equation proposed by Sarkisov [J.

Direct excess entropy calculation for a Lennard-Jones fluid by the integral equation method.

The present work is devoted to the calculation of excess entropy by means of correlation functions, in the framework of integral equation theory. The tangent linear method is set up to get exact thermodynamic derivatives of the pair-correlation function, essential for the calculation of the physical quantities, as well as to carry out an optimization process for the achievement of thermodynamic consistency. The two-body entropy of the Lennard-Jones fluid is in very good agreement with the available molecular dynamics results, attesting the high degree of accuracy of the integral equation scheme.

Does nutritive and non-nutritive sucking reduce other oral behaviors and stimulate rest in calves?

After a milk meal, bucket-fed calves show non-nutritive oral activities, including cross-sucking, and this can discourage producers from rearing them in groups. Sucking is known to induce a quiet state in humans and rats. We examined if nutritive sucking affects non-nutritive oral activities in calves, if it reduces arousal (assessed through behavior and cardiac activity), and if sucking a dry teat can compensate for the lack of nutritive sucking.