Preprints  

We extend an approach for visualizing dynamics of quantum spin systems based on angular momentum probability (AMP) surfaces to visualizing coherences via angular momentum coherence (AMC) surfaces. AMP/AMC surfaces conveniently represent symmetries of density matrices and allow spotting their presence (orientation, alignment, etc.) or absence even when direct analysis of density matrices is not obvious. We apply novel visualization approach to represent relevant cases of 2-spin system dynamics.

This works examines the physics underlying double electron-electron resonance (DEER) spectroscopy, a magnetic-resonance method that provides nanoscale data about protein structure and conformations.

Egyptian mummies were covered with an enigmatic black organic matter. Its chemical composition is classically determined by molecular analysis methods, which are destructive by nature. In a new analytical approach based on ¹H and ¹⁴N magnetic resonance, we use V⁴⁺ ions, existing at trace level in this black matter, as an internal paramagnetic probes for a non-destructive exploration of the material. The results suggest that a common recipe was used for animal and human mummies of different ages.

We report in this article a multiscale approach for explaining why the transport of fluids in oil shales is so hindered. Thanks to nuclear and electronic magnetic resonances, we first demonstrate that the kerogen within the shale is capable of swelling in the presence of oil, second we show that this swelling is reversible and reveals the presence of vanadyl porphyrin by breaking magnetic interaction. The magnetic locking evidenced here helps understanding the very low mobility of hydrocarbons.

A straight forward rather accurate approach to extract quantitative restraints for the structure calculation of ligand-protein complexes is presented.

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.