Geoffrey Bodenhausen

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A new NMR method for the study of ligand protein interactions exploits the unusual lifetimes of long-lived states (LLSs). The new method provides better contrast between bound and free ligands and requires a protein-ligand ratio ca. 25 times lower than for ...

By analogy to heteronuclear systems, coherence can be transferred adiabatically in the rotating frame between two selected spins I and S belonging to a homonuclear network of scalar-coupled spins. In contrast to cross polarization with const. radiofrequency field amplitudes, the transfer function obtained with adiabatic methods depends in a monotonic, nonoscillatory manner on the duration of the transfer interval. The efficiency of the transfer does not depend on the magnitude of the scalar coupling const.

Despite the powerful spectroscopic information it provides, Nuclear Magnetic Resonance (NMR) spectroscopy suffers from a lack of sensitivity, especially when dealing with nuclei other than protons. Even though NMR can be applied in a straightforward manner when dealing with abundant protons of organic molecules, it is very challenging to address biomolecules in low concentration and/or many other nuclei of the periodic table that do not provide as intense signals as protons. Dynamic Nuclear Polarization (DN

Cross-correlated fluctuations of isotropic chem. shifts can provide evidence for slow motions in biomols. Slow side-chain dynamics have been investigated in 15N and 13C enriched ubiquitin by monitoring the relaxation of Ca-Cb two-spin coherences (Frueh et al., 2001). This method, which had hitherto been demonstrated only for protonated ubiquitin, has now been applied to both protonated and deuterated proteins. Deuteration reduces the dipole-dipole contributions to the DD/DD cross-correlation, thus facilitat

Proton-coupled 13C NMR spectra were studied by a technique which involves Fourier transformation of spin echo modulation. When the protons are strongly coupled, the "proton flip" version of this expt. generates a new form of 13C spectrum which is quite distinct from the multiplet structure of the conventional NMR spectrum. The transition frequencies and intensities are exactly sym. about the center frequency and some lines have neg. intensities. Exptl. spectra from the C2 site in pyridine are presented an

The allocation of resources for research is increasingly based on so-called ‘bibliometrics’. Scientists arenow deemed to be successful on the sole condition that their work be abundantly cited. This world-wide trendappears to enjoy support not only by gran ...

As a simple approach to 3-dimensional NMR spectroscopy a novel type of expt. is proposed in which the dimension is reduced from 3 to 2 by synchronous incrementation of evolution period t, and the mixing time tm parameters: tm = Kt1. Because of the concerted stretching of the pulse sequence, this expt. is referred to as accordion spectroscopy. The salient feature of the novel expt. is the accommodation of 2-dimensional information along a single time or frequency axis. In complete analogy to std. 2-dimension

Two novel schemes are described for cross polarization in NMR that make it possible to achieve an efficient transfer of polarization from abundant I spins to dil. S spins under high-speed magic angle spinning spectroscopy, which is useful for systems with large chem. shift anisotropies at high fields. The frequency of one of the RF carriers is modulated sinusoidally during spin-locking while the RF amplitude is kept const. It is shown by expt. that frequency modulation greatly attenuates the crit. character

A pulsed field gradient NMR (= nuclear magnetic resonance) method using stimulated echoes for determining the translational isotropic or anisotropic diffusion coefficient of a molecule or supramolecular assembly or the flow rate and direction of fluids containing such molecules is characterized in that the molecule or supramolecular assembly contains one or several isotopes (X) of non-zero nuclear spin other than protons having longitudinal relaxation times T1(X) that are longer than the longitudinal relaxa

Hyperpolarization is generated by dissolution dynamic nuclear polarization (d-DNP) using a polymer-based polarizing agent dubbed FLAP (filterable labeled agents for polarization). It consists of a thermo-responsive poly(N-isopropylacrylamide), also known a ...

At the interface between solid surfaces and cavities filled with gaseous or liq. Xe, the nuclear magnetization of 131Xe (S = 3/2) is subject to quadrupolar interactions which may lead to higher rank single-quantum coherences that can be described by tensor elements T2,+-1 and T3,+-1. This can be demonstrated by multiple-quantum filtered (MQF) NMR expts. In gaseous Xe on Pyrex surfaces, the primary source of such coherences is coherent evolution induced by a nonvanishing av. quadrupolar coupling. In this con

New amplitude-modulated radio-frequency pulses are proposed that allow one to achieve selective excitation, de-excitation, inversion, and refocusing of spin-1/2 systems in NMR. The rotation angles and axes are well defined over a chosen bandwidth, regardless of the initial conditions. These universal pulses are derived from the idea of Gaussian pulse cascades, but their design is guided by new principles. The amplitude profiles are optimized by calcg. the quaternions representing the propagators of the over

Longitudinal nuclear magnetic relaxation in coupled two-spin systems is discussed in terms of magnetization transfer modes, a generalization of the magnetization modes commonly used in the discussion of one-dimensional NMR relaxation expts. The symmetry properties of the transfer modes and their relationship to the elements to the usual Redfield relaxation matrix are discussed. Exptl. strategies for measuring the amplitudes of the transfer modes are discussed and various selective two-dimensional exchange (

The present invention concerns materials consisting in a porous and structured network, this network being at least in part formed by Si atoms, or Si atoms and metal atoms, linked to each other by oxy bridges, comprising organic molecules which include at ...

Chem. shifts and scalar coupling consts. were extd. by symmetry mapping of multiplets in 2-dimensional NMR spectra. The procedure relies on the fact that, in addn. to symmetry with respect to the centers of the multiplets, substructures embedded within the multiplets are partly sym. The recursive anal. is reliable even in the presence of accidental degeneracies, strong coupling, and broad lines as occur in macromols. With minor modifications, the algorithms can be used both for 2D correlation spectra (COSY)

In systems with homonuclear scalar couplings, the envelopes of spin echoes obtained with simple refocusing pulses or trains of such pulses are normally modulated so that it is difficult to extract transverse relaxation rates. It has been shown recently that echo modulations can be quenched by cumulative pulse errors that arise after applying a large number of refocusing pulses with moderate rf amplitudes. The resulting unmodulated decays allow one to extract apparent transverse relaxation rates. Early work

Frequency-modulated chirp pulses, for exciting multiple-quantum coherences over large bandwidths, can be considered as an alternative to composite pulses to combat the effects of large offsets and tilted effective fields. Refocusing of the phase dispersion of double-quantum coherence can be combined with suitable detection sequences to yield pure absorption 2-dimensional double-quantum spectra. The method of sym. excitation and detection by time-reversal may be applied to obtain t1-modulated longitudinal ma

A novel NMR method characterizes slow motions in proteins by multiple refocusing of double- and zero-quantum coherences of amide protons and nitrogen-15 nuclei. If both nuclei experience changes in their isotropic chem. shifts because of internal motions on slow time scales (ms-ms), this leads to a difference in the relaxation rates of double- and zero-quantum coherences. This is due to CSM/CSM (chem. shift modulation) cross-correlation effects that are related to the well-known chem. exchange contribution

The surface of gamma-alumina nanoparticles can be characterized by dynamic nuclear polarization (DNP) surface-enhanced NMR of Al-27. DNP is combined with cross-polarization and MQ-MAS to determine local symmetries of Al-27 sites at the surface. ...

A novel technique is described that allows one to measure cross-relaxation rates (Overhauser effects) between 2 selected nuclei in high-resoln. NMR. The 2 chosen sites are irradiated simultaneously with the sidebands of an amplitude-modulated radiofrequency field, so that their magnetization vectors are forced to undergo a simultaneous motion, which is referred to as synchronous nutation. From the time-dependence obsd. for different initial conditions, one may derive cross-relaxation rates, and hence det. i

Geoffrey Bodenhausen

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Boosting the Sensitivity of Ligand-Protein Screening by NMR of Long-Lived States

Adiabatic coherence transfer in magnetic resonance of homonuclear scalar-coupled systems

NMR of Insensitive Nuclei Enhanced by Dynamic Nuclear Polarization

Evidence of Slow Motions by Cross-Correlated Chemical Shift Modulation in Deuterated and Protonated Proteins

Proton-coupled carbon-13 J spectra in the presence of strong coupling. II

Bibliometrics as Weapons of Mass Citation - La bibliométrie comme arme de citation massive

The accordion experiment, a simple approach to three-dimensional NMR spectroscopy

Frequency-modulated cross-polarization for fast magic angle spinning NMR at high fields: relaxing the Hartmann-Hahn condition

SLOW DIFFUSION AND FLOW OF MOLECULES MEASURED BY PULSED FIELD GRADIENT NMR USING LONGITUDINAL MAGNETISATION OF NON-PROTON ISOTOPES

Filterable Agents for Hyperpolarization of Water, Metabolites, and Proteins

Probing Aerogels by Multiple Quantum Filtered 131Xe NMR Spectroscopy

Optimization of shaped selective pulses for NMR using a quaternion description of their overall propagators

Magnetization transfer modes in scalar-coupled spin systems investigated by selective two-dimensional nuclear magnetic resonance exchange experiments

Structured and porous materials particularly suitable as polarizing agents in dissolution dynamic nuclear polarization

Symmetry mapping and recursive reduction of multiplet patterns in nuclear magnetic resonance spectra obtained with two-dimensional correlation and multiple-quantum methods

Apparent transverse relaxation rates in systems with coupled carbon-13 spins

Multiple-quantum NMR with frequency-modulated chirp pulses

Evidence for slow motion in proteins by multiple refocusing of heteronuclear nitrogen/proton multiple quantum coherences in NMR

Dynamic nuclear polarization of quadrupolar nuclei using cross polarization from protons: surface-enhanced aluminium-27 NMR

Measurement of cross relaxation between two selected nuclei by synchronous nutation of magnetization in nuclear magnetic resonance