Interplay between magnetism and conductivity derived from spin-polarized donor radicals.

Tutorial review: to achieve molecule-based spintronic devices, an organic conducting magnet that exhibits both conductivity and magnetism in a cooperative manner must be constructed. As a building block for such new materials, a spin-polarized donor radical, which serves as a molecular "spin-filter" in its singly oxidized state, was designed and synthesized. The resistivity of ion radical salts of selenium-substituted, tetrathiafulvalene-based spin-polarized donor radicals decreased substantially in the presence of a magnetic field, thus indicating cooperative conductivity and magnetism.

Influence of magnetic field upon the conductance of a unicomponent crystal of a tetrathiafulvalene-based nitronyl nitroxide.

A spin-polarized donor, BTBN, which is a dibromotetrathiafulvalene derivative containing a nitronyl nitroxide group in a cross-conjugated manner, was prepared. Upon hole injection from an electrode, the neutral microcrystals of BTBN exhibited nonlinear I-V characteristics that were interpreted in terms of the space-charge-limited conduction (SCLC) mechanism. Moreover, the resistance of BTBN decreased upon application of a magnetic field below 30 K and exhibited a giant negative magnetoresistance of (R(H) - R(0))/R(0) = -76% at 2 K under 5 T.

Age-related changes in the human pulpal blood flow measured by laser Doppler flowmetry.

The purpose of this study was to examine the age-related changes in human pulpal blood flow (PBF). Recordings were taken from 22 clinically healthy upper central incisors in 22 healthy participants (age: 8-75 years). A Moor blood flow monitor (type MBF3D) was used to measure PBF; and subjects' electrocardiogram (ECG), mean blood pressure (BP) and heart rate (HR) were also recorded.