Session ThOB. There are 6 abstracts in this session.



Session: New Science, time: 08:30am-08:50am

Three-Spin Solid Effect and the Spin Diffusion Barrier in Amorphous Solids


Kong Ooi Tan1; Michael Mardini1; Chen Yang1; Jan Henrik Ardenkjaer-Larsen2; Robert Griffin1
1MIT, Cambridge, MA; 2Technical University of Denmark, Kgs Lyngby, DK
The solid effect (SE) is a DNP mechanism that hyperpolarizes the nuclei when the microwave offset matches the nuclear Larmor frequency. Here we report an enhancement of ~170 when the microwave offset matches twice the nuclear Larmor frequency, using trityl dispersed in a glycerol/water glassy matrix at 0.35 T and 80 K. A theoretical analysis and numerical simulations confirm that the effect is attributable to an electron-nuclei-nuclei system, i.e. a three-spin solid effect (TSSE). As the TSSE enhancement is sensitive to the electron-nuclear distances, we exploit this feature to probe the polarization transfer pathway from the radical to the bulk nuclei. In particular, our results show that the spin diffusion barrier is less than 6 Å.

Session: New Science, time: 08:50am-09:10am

Rotor-synchronous Non-CW DNP Under Magic-Angle Spinning


Asif Equbal; Kan Tagami; Songi Han
University of California, Santa Barbara, CA

CHIRP-DNP has improved the performance of CW-DNP by several fold for broad-line radical. However, its development is limited to Static-sample only. Here, the nuances of broadband, rotor-synchronized microwave irradiation for DNP will be explored, for the first time, under MAS- where DNP mechanism is very different from static case. Unlike under static conditions, CHIRP- irradiation becomes deleterious under MAS for bis-nitroxide radical (AMUPOL) owing to its very large electron spins energy modulations. However, CHIRP-irradiation can be successfully implemented for mixed-radical system by selectively manipulating the saturation profile of narrow-line radical. For tethered TempTriPol spin-system, CHIRP-DNP shows ~20% greater enhancement than CW-DNP at 10kHz spinning—an exciting proof of principle. Enhancement can be further improved by ~50% using sophisticated MW-pulse schemes, like WURST.

Session: New Science, time: 09:10am-09:30am

Generating, Storing and Transporting Hyperpolarization with HYPOP (Hyperpolarizing Porous Polymers)


Théo El Daraï1; Damien Montarnal2; Samuel Cousin1; Arianna Ferrari1; David Gajan1; Morgan Ceillier1; Olivier Cala1; Sami Jannin1
1CRMN Lyon, Villeurbanne, France; 2CPE Lyon, Villeurbanne, France
In our group, we have in the past years, been working at improving efficiency, compatibility, and repeatability of d-DNP, and it has led us to develop a new concept i) to dramatically extend hyperpolarization lifetimes from minutes to days and, ii) to enable transport to far distant MRI or NMR sites.

We are now generalizing this new concept by developing new hyperpolarizing solids such as hyperpolarizing porous polymers (HYPOP). These can be impregnated with arbitrary solutions that are then hyperpolarized efficiently and stored and transported over hours.

We will present a new epoxy-based polarizing material and show how the porosity and morphology can be tuned, and we will present DNP results on the very first generation of these new materials

Session: New Science, time: 09:30am-09:50am

A New Approach of Time-Ordered Exponential in NMR: the Path-Sum.     


Christian Bonhomme1; Pierre-Louis GISCARD2
1Sorbonne Universite, Paris, France; 2Université Littoral Côte d'Opale, Calais, FRANCE
In this contribution we introduce a new mathematical approach (named “path-sum”) to understand the dynamical behaviour of quantum systems driven by time-varying Hamiltonians with explicit applications to NMR. Path-sum arises from exact resummations of infinite families of system histories, which are discrete analogs to Feynman-diagrams. This novel theoretical approach is fundamentally different from standard Floquet-Magnus treatment and opens new avenues to obtain the time-ordered exponential (OE) in an exact and compact form. Several applications in NMR (including (1) Bloch-Siegert effect in two level systems ; (2) N-spins systems) will be highlighted.
 

Session: New Science, time: 09:50am-10:10am

Efficient Spin-Relayed Heteronuclear Long-Range Signal Amplification by Reversible Exchange


Roman Shchepin2; Jonathan Birchall1; Nikita Chukanov3, 4; Kirill Kovtunov3, 4; Igor Koptyug3, 4; Thomas Theis5; Warren S. Warren6; Juri Gelovani1; Boyd M. Goodson7; Matthew Rosen8; Yi-Fen Yen8; Wellington Pham2; Eduard Y. Chekmenev1, 9
1Wayne State University, Detroit, MI; 2Vanderbilt University (VUIIS), Nashville, TN; 3International Tomography Center, SB RAS, Novosibirsk, Russia; 4Novosibirsk State University, Novosibirsk, Russia; 5North Carolina State University, Raleigh, NC; 6Duke University, Durham, NC; 7Southern Illinois University, Carbondale, IL; 8MGH/A.A. Martinos Center, Boston, MA; 9Russian Academy of Sciences, Moscow, Russia
NMR hyperpolarization of uniformly 15N-labeled metronidazole-15N3 is demonstrated using SABRE-SHEATH (Signal Amplification by Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei). In this antibiotic, a 15NO2 group is hyperpolarized via spin relays created by 15N spins in metronidazole-15N3, and the polarization is transferred from parahydrogen-derived hydrides over six chemical bonds. In less than a minute of parahydrogen bubbling at ~0.4 microtesla, a high level of nuclear spin polarization P15N of ~16% is achieved on all three 15N sites of metronidazole-15N3 at up to ~41 mM concentration. At 1.4 T, the hyperpolarized state of the 15NO2 group persists for tens of minutes (T1~10 min), in part because its 15N spin has no detectable spin-spin couplings with protons of the molecule.

Session: New Science, time: 10:10am-10:30am

Studies of Biofilms in Yellowstone National Park and Violins of the Cremona Masters by Mobile NMR


Bernhard Bluemich1; Christian Rehorn1; Denis Jaschtschuk1; Michael Adams1; Sarah Codd2; Catherine Kirkland2; Brent Peyton2; Joseph Seymour2
1RWTH Aachen University, Aachen, Germany; 2Montana State University, Bozeman, MO
The NMR-MOUSE has been adapted to operate with a car battery and an electric generator in locations without access to the electric power grid. This enabled us to analyze the asphalt quality of roads and ancient frescoes in excavation sites nondestructively. Recently, this instrumentation has been employed to identify biofilms in Yellowstone National Park in search for life under extraordinary conditions. Moreover, depth profiles through the wood of precious violins made by the famous Cremona masters revealed hitherto unknown surface structures in the wood panels. The experimental conditions and the results from the biofilm and violin measurements will be reported.