Sound scattering from two concentric fluid spheres (L)

The solution to the problem of plane wave and point source scattering by two concentric fluid spheres is derived. The effect of differences in sound speed, density, and absorption coefficient is taken into account. The scattered field is then found in the limit as the outer sphere becomes an infinitely thin shell and compared to the solution for a single fluid sphere for verification. A simulation is then performed using the concentric fluid sphere solution as an approximation to the human head and compared to the solution of a single fluid sphere with the properties of either bone or water. The solutions were found to be similar outside of the spheres but differ significantly inside the spheres.     

Electron spin density distribution in the polymer phase of CsC60: assignment of the NMR spectrum

We present high resolution 133Cs-13C double resonance NMR data and 13C-13C NMR correlation spectra of 13C enriched samples of the polymeric phase of CsC60. These data lead to a partial assignment of the lines in the 13C NMR spectrum of CsC60 to the carbon positions on the C60 molecule. A plausible completion of the assignment can be made on the basis of an ab initio calculation. The data support the view that the conduction electron density is concentrated at the C60 "equator," away from the interfullerene bonds.     

Detection of Liposome Lysis Utilizing an Enzyme–Substrate System

A novel optical reporter system was developed to verify encapsulation and subsequent release of a foreign molecule in liposomes. The protocol utilizes a single enzyme and substrate. We encapsulate o-nitrophenyl-β,d-galactopyranoside (ONPG) and measure its release by detecting the levels of o-nitrophenol created when the encapsulated ONPG is released and hydrolyzed by β-galactosidase. Using this method, liposome formation and subsequent lysis with Triton X-100 were verified. This new protocol eliminates the complications of multiple reaction enzyme detection methods, along with the chance for false negatives and unreliable data seen when using fluorescent particles as reporters.