No abstract

No abstract

The magnetization generated by the interaction of stable radicals with photoexcited triplets in a viscous solution at room temperature was measured by light-induced Fourier transform electron paramagnetic resonance spectroscopy (FT-EPR). High and long-lived polarized magnetization (>100 µs in emission) is generated in the stable radical (R,γ-bisdiphenylene-β-phenylallyl) interacting with the photoexcited triplet state of free base, and Zn, tetraphenylporphyrin. Radical-triplet interaction was analyzed quantitatively employing a combined model of electron spin polarization transfer (ESPT) and radical-triplet pair mechanism (RTPM). The presented model allows calculating the radical polarization following an encounter with a thermal or nonthermal triplets. Moreover, an important conclusion from this study is that the generation of radical polarization via RTPM does not require efficient quenching of the photoexcited triplet.

The self-contained intravascular MRI catheter successfully identified TCFA and may prove to be an important diagnostic approach to determining the presence of lesions with increased risk of causing death or myocardial infarction.

A three-dimensional (3D) electron spin resonance (ESR) microimaging system, operating in pulse mode at 9GHz is presented. This microscope enables the acquisition of spatially resolved magnetic resonance signals of free-radicals in solid or liquid samples with a resolution of up to ∼3.5×7×11.4μm in 20min of acquisition. The detection sensitivity at room temperature is ∼1.2×109spins∕√Hz, which enables the measurement of ∼2×107 spins in each voxel after 60min of acquisition. The resolution and detection sensitivity are the best obtained so far for ESR at ambient conditions of temperature and pressure. This ESR microscope can be employed in the investigation of a variety of samples in the fields of botany, life sciences, and materials science.