MR method for measuring microscopic histologic soft tissue textures.

Purpose: Provide a direct, non-invasive diagnostic measure of microscopic tissue texture in the size scale between tens of microns and the much larger scale measurable by clinical imaging. This paper presents a method and data demonstrating the ability to measure these microscopic pathologic tissue textures (histology) in the presence of subject motion in an MR scanner. This size range is vital to diagnosing a wide range of diseases.

Improved quantum efficiency for electroluminescence in semiconducting polymers.

Some conjugated polymers have luminescence properties that are potentially useful for applications such as light-emitting diodes, whose performance is ultimately limited by the maximum quantum efficiency theoretically attainable for electroluminescence, ,. If the lowest-energy excited states are strongly bound excitons (electron-hole pairs in singlet or triplet spin states), this theoretical upper limit is only 25% of the corresponding quantum efficiency for photoluminescence: an electron in the π-band and a hole (or missing electron) in the π-band can form a triplet with spin multiplicity of three, or a singlet with spin multiplicity of one, but only the singlet will decay radiatively. But if the electron-hole binding energy is sufficiently weak, the ratio of the maximum quantum efficiencies for electroluminescence and photoluminescence can theoretically approach unity.