Biomedical subjects

Warren S Warren

Publications and source records attributed to Warren S Warren.

2 recordsLinked to original sources

PubMed2003

Femtosecond phase-coherent two-dimensional spectroscopy.

Femtosecond phase-coherent two-dimensional (2D) spectroscopy has been experimentally demonstrated as the direct optical analog of 2D nuclear magnetic resonance. An acousto-optic pulse shaper created a collinear three-pulse sequence with well-controlled and variable interpulse delays and phases,which interacted with a model atomic system of rubidium vapor. The desired nonlinear polarization was selected by phase cycling (coadding experimental results obtained with different interpulse phases). This method may enhance our ability to probe the femtosecond structural dynamics of macromolecules.

Chemical Phenomena↗

PubMed2002

Magnetization structure contrast based on intermolecular multiple-quantum coherences.

In vivo and ex vivo MRI based on intermolecular multiple-quantum coherences (iMQC) is predicted to provide a fundamentally different source of contrast for MRI. This article investigates the dependence of image contrast upon the choice of correlation distance for a heterogeneous material. A closely packed array of parallel hollow cylinders was used to demonstrate signal intensity variations when the correlation distance becomes comparable to the gap size between the cylinders. The observed effects agree well with three-dimensional calculations of the time evolution of magnetization under the nonlinear Bloch equations.

Contrast Media↗