Abstracted/indexed

This work is discussing NMR experiments, which make use of coherent spin evolution at level-anti crossings. In this work, we provide a common description of such phenomena (hopefully, a reasonably simple one), which is illustrated by a number of examples from various subfields of NMR.

This work presents systematic methodological study of one of the types of the Nuclear Magnetic Resonance experiments that enables studying molecular dynamics on a millisecond time scale. A modification of a standard experiment was suggested that excludes possible artifacts and distortions. It has been demonstrated that the standard experiment reveals slow overall motion of proteins in a rigid crystal lattice, while the artefact-free experimental setup demonstrates that the proteins are rigid.

The sensitivity of magnetic resonance imaging can be increased by coupling of the less sensitive nuclear spins which are excited at radio-frequencies to unpaired electron spins of radicals which are excited at microwave frequencies. Here we demonstrate how an Fabry-Perot type microwave resonance structure can be used to significantly enhance the polarization transfer from electron to water proton nuclear spins under constant flow conditions for imaging applications at 1.5 T.

Through a series of DEER measurements on two Gd-rulers, with Gd-Gd distances of 2.1 and 6.0 nm, we show that artefacts commonly observed when measuring short distances can be eliminated by avoiding excitation of the central transition by both the pump and observer pulses. By using a wideband induction mode sample-holder at 94 GHz, we demonstrate that high quality DEER measurements will become possible using Gd spin labels at sub-uM concentrations, with implications for in-cell DEER measurements.

Here we demonstrate that Electron Spin Resonance (ESR) spectroscopy at millikelvin temperatures can be performed with a spectrometer comprised of a thin-film superconducting resonator and Josephson Parametric Amplifier (JPA) with sufficient bandwidth to detect Electron Spin Echo Envelope Modulation (ESEEM) while maintaining high spin-detection sensitivity.

Magnetic resonance detectors require a high degree of precision to be useful. Their design must e.g. carefully weigh field strength and field homogeneity, to find the best compromise. Here we show that inverse computational design is a viable method to find such a compromise. Apart from the electromagnetic field solution, the simulation program also determines the boundary between insulating and conducting material, and moves the material boundaries around until the compromise is best satisfied.

We have studied spin dynamics in nuclear spin systems at low magnetic fields, where “strong coupling” among nuclear spins of the same kind, here C-13, is expected. Such conditions are known to be favorable for coherent polarization transfer. However, to our surprise, interactions to other nuclei, here protons, lead to breakdown of the strong coupling conditions. By using a two-field NMR approach, we are able to manipulate low-field spin dynamics and reintroduce strong coupling.

With a pulsed dipolar EPR technique named Double Electron-Electron Resonance, we measure nanometer distances between spin labels attached to biomolecules. If more than one spin type is present (A and B), we can separately address AA, AB and BB distances via distinct spectroscopic channels, increasing the information content per sample. Here we investigate the appearance of unwanted channel crosstalks and suggest ways to identify and suppress them, thereby increasing signal fidelity.

Dipolar EPR spectroscopy methods such as DEER provide data on how proteins change shape, thus giving detailed insight into how proteins work. We present DeerLab, a comprehensive open-source software for completely and reliably analyzing the associated data. The software implements a series of theoretical and algorithmic innovations and thereby improves the quality and reproducibility of data analysis.

Nowadays, almost all MRI technique used in clinical applications are based on a Fourier transformation of the raw data. Alternative non-Fourier magnetic resonance imaging techniques can offer some advantages under certain conditions. SPatio-temporal ENcoding (SPEN) is a non-Fourier method that usually employs frequency-swept radio frequency pulses and can give good images in inhomogeneous magnetic fields. In this work we show how one can improve this technique by using quadratic gradients.