The plane-wave primary reflection response from an impedance gradient interface.

A weak scattering model that allows prediction of the one-dimensional acoustic plane wave primary reflection response from an impedance gradient interface is described. The velocity and density gradient profiles are represented by a smooth approximation to the Heaviside function of the Fermi-Dirac distribution type. The profiles are described by the velocities and densities at minus and plus infinity, the reference depth of the gradient interface, and its smoothness.

Characterization of interface reflection coefficients using a finite-difference injection technique.

In this paper, a numerical wave field injection technique for characterizing the reflection coefficient of a planar medium interface is proposed. By injecting recorded wave field quantities into a three-dimensional (3D) finite-difference calculation, two key objectives are addressed: first, the recorded wave field is separated into its incident and reflected constituents without the need of spatial Fourier transforms or a temporal separation of incident and reflected parts in the recorded data. Second, the separated constituents are independently extrapolated to the location of the reflecting interface to determine its reflecting properties.

Physical exercise for cancer patients with advanced disease: a randomized controlled trial.

Background: Physical exercise can improve cancer patients' functioning and reduce their symptom levels. A randomized, controlled trial was launched to test the hypothesis that physical exercise reduces fatigue and improves physical performance in cancer patients with advanced and incurable disease.

Methods: Cancer patients (n = 231) with a life expectancy ≤2 years were randomized to a physical exercise group (PEG, n = 121) or a control usual care group (UCG, n = 110).

The testosterone binding mechanism of an antibody derived from a naïve human scFv library.

A testosterone binding scFv antibody was isolated from a naïve human library with a modest size of 10(8) clones. The crystal structure of the Fab fragment form of the 5F2 antibody clone complexed with testosterone determined at 1.5 Å resolution shows that the hapten is bound deeply in the antibody binding pocket.