In vivo MRI of hyperpolarized silicon-29 nanoparticles.

Purpose: The objective of the present work was to test the feasibility of in vivo imaging of hyperpolarized 50-nm silicon-29 (Si) nanoparticles.

Methods: Commercially available, crystalline 50-nm nanoparticles were hyperpolarized using dynamic polarization transfer via the endogenous silicon oxide-silicon defects without the addition of exogenous radicals. Phantom experiments were used to quantify the effect of sample dissolution and various surface coating on T and T relaxation.

Frequency-Chirped Magic Angle Spinning Dynamic Nuclear Polarization Combined with Electron Decoupling.

Magic angle spinning (MAS) dynamic nuclear polarization (DNP) increases the signal intensity of solid-state nuclear magnetic resonance. DNP typically uses continuous wave (CW) microwave irradiation close to the resonance frequency of unpaired electron spins. In this study, we demonstrate that frequency-chirped microwaves improve DNP performance under MAS.

Watch-sized 12 Tesla all-high-temperature-superconducting magnet.

We demonstrate the construction of 7 Tesla and 12 Tesla all high-temperature-superconducting (HTS) magnets, small enough to fit on your wrist. The size of the magnet reduces the cost of fabrication, decreases the fringe field to permit facile siting of magnets, and decreases the stored energy of high field magnets. These small HTS-based magnets are being developed for gyrotron microwave sources for use in high-field nuclear magnetic resonance applications.

Cryogenic-compatible spherical rotors and stators for magic angle spinning dynamic nuclear polarization.

Cryogenic magic angle spinning (MAS) is a standard technique utilized for dynamic nuclear polarization (DNP) in solid-state nuclear magnetic resonance (NMR). Here we describe the optimization and implementation of a stator for cryogenic MAS with 9.5 mm diameter spherical rotors, allowing for DNP experiments on large sample volumes.

Improving the sensitivity of MAS spheres using a 9.5 mm spherical shell with 219 μL sample volume spinning in a spherical solenoid coil.

Spherical rotors in magic angle spinning (MAS) nuclear magnetic resonance (NMR) experiments have potential advantages relative to cylindrical rotors in terms of ease of fabrication, low risk of rotor crash, easy sample exchange, and better microwave access. However, one major disadvantage so far of spherical rotors is poor NMR filling factor due to the small sample volume and large cylindrical radiofrequency (RF) coil. Here we present a novel NMR coil geometry in the form of a spherical coil.