Preprints  

Investigations of metal-organic frameworks are presented. This substance class is of interest for applications in gas storage (hydrogen, methane), separation, catalysis and sensor technology. The properties of the material depend on the mobility of alkyl or alkyloxy side chains. We have determined that the side chain methylene groups move highly anisotropically with a relatively short correlation time. Furthermore we could improve the analysis procedure for the experiment used here.

Deuterium Metabolic Imaging (DMI) is a novel method to obtain images of dynamic metabolism in the living human brain. While DMI is generally simple and robust, small signals from deuterated skull lipids can distort the metabolic information within the brain. Here we use MRI-based information on brain and skull locations to remove lipid signals from DMI data. With an average 90 % lipid removal, DMI is used to generate distinct and artifact-free metabolic maps on patients with brain tumors.

In nuclear magnetic resonance, the magnetization of abundantly present nuclei contributes to the overall field felt by the same nuclei through intermolecular dipolar interactions. This has led to many surprising discoveries, such as multiple spin echoes and intermolecular cross-peaks in 2D spectroscopy. In this work, the effect of the dipolar field under continuous irradiation is investigated. Various methods to obtain intermolecular transfer of phase coherences are presented.

We recently freed the solid effect of dynamic nuclear polarization (DNP) from its classical, perturbative treatment by describing the relevant spin dynamics in time domain. This allows us to easily account for dynamical processes that modulate the spin interactions in liquids. Here we model the slow rotational diffusion of the polarizing agent, in addition to the translational diffusion of the spins described previously, and analyze DNP data from nitroxide spin-labels in lipid bilayers at 9.4 T.

The magic angle spinning (MAS) technique of solid state NMR requires samples to be rapidly rotated within a magnetic field. The rotation rate speed record is 150 kHz, or 9 million RPM, and hence MAS turbines hold the world rotation speed record for extended objects. The containers holding the samples are made of the strongest materials known, to be able to withstand the excessive centrifugal forces. To overcome the speed limit, this paper delineates a way to do so using an optical tweezers setup

Providing evidence that proteins are dynamical molecules is a major contribution of solution NMR to structural biology. But the classical experiments to measure dynamics can only be applied to small proteins. This is regretful, because larger proteins often display conformational changes in which dynamics plays a functional role. We show here that dynamic information can be extracted from HSQC NMR spectra using a computational approach. Such spectra are widely available also for larger proteins.

We show here that information about protein molecular dynamics can be directly extracted out of a single NMR spectrum. Understanding protein dynamics is essential to understanding its function, energetics and biology. We hope that this contribution helps bring this insight to a much broader application field and audience community than previously possible.

The demonstration of the Finite Pulse Radio Frequency Driven Recoupling experiment was firstly published over the past 20 years. Since it has become one of the used experiments. In this article we consider that experiment using other theoretical and simulated approaches with respect to the previous works. These approaches help us to understand more clearly the influence of each part of that experiment and to see how exactly the spin system is evaluated during it.

We recently added 2D NMR spectroscopy to the well-established techniques able to obtain information on the process of unfolding using resonances of residues in the hydrophobic core of a protein. We asked whether a detailed analysis of the individual stability curves could provide additional site-specific information. By monitoring both cold and heat denaturation of individual residues we convincingly demonstrate that the two unfolding processes are intrinsically different.

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.