Publications de Puneet Ahuja | EPFL Graph Search

Method for nuclear magnetic resonance (NMR) spectroscopy measurements using long-lived coherences (LLC)

Geoffrey Bodenhausen, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

A method for nuclear magnetic resonance (NMR) spectroscopy of a sample comprises preparation of the sample and carrying out an NMR spectroscopy measurement. Preparation includes excitation of long lived coherences (LLC) between the singlet state S0 and the ...

2013

Long-Lived States to Monitor Protein Unfolding by Proton NMR

Geoffrey Bodenhausen, Riddhiman Sarkar, Aurélien Bornet, Paul Romeo Vasos, Puneet Ahuja

The relaxation of long-lived states (LLS) corresponds to the slow return to statistical thermal equilibrium between symmetric and antisymmetric proton spin states. This process is remarkably sensitive to the presence of external spins and can be used to ob ...

Wiley-Blackwell2011

Hyperpolarizing Gases via Dynamic Nuclear Polarization and Sublimation

Arnaud Comment, Jean-Philippe Ansermet, Geoffrey Bodenhausen, François Lazeyras, Rolf Gruetter, Sami Jannin, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja, Pascal Miéville, Jean-Noël Hyacinthe

A high throughput method was designed to produce hyperpolarized gases by combining lowtemperature dynamic nuclear polarization with a sublimation procedure. It is illustrated by applications to 129Xe nuclear magnetic resonance in xenon gas, leading to a si ...

American Physical Society2010

Scavenging Free Radicals To Preserve Enhancement and Extend Relaxation Times in NMR using Dynamic Nuclear Polarization

Arnaud Comment, Geoffrey Bodenhausen, Sandrine Gerber, Rolf Gruetter, Sami Jannin, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja, Pascal Miéville, Mor-Miri Mishkovsky

Vitamin C for longer lifetimes: N-oxide radicals that are widely used for dynamic nuclear polarization can be reduced by scavengers such as sodium ascorbate (vitamin C) during the dissolution process, thus diminishing losses of polarization during the tran ...

Wiley-Blackwell2010

Applications of Long-Lived Spin States to High Resolution NMR Studies of Biomolecules

Puneet Ahuja

Slow dynamic processes, such as biomolecular folding/unfolding, macromolecular diffusion, etc., can be conveniently monitored by solution-state two-dimensional (2D) NMR spectroscopy, provided the inverse of their rate constants does not exceed the nuclear ...

EPFL2010

Diffusion Coefficients of Biomolecules Using Long-Lived Spin States

Geoffrey Bodenhausen, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

We report the first observation of long-lived states (LLS) having lifetimes TLLS that exceed the corresponding spin−lattice relaxation times T1 by more than a factor 6 in a protein. Slow diffusion coefficients characteristic of large biomolecules can be de ...

2009

Long-lived states to sustain hyperpolarized magnetization

Arnaud Comment, Jean-Philippe Ansermet, Geoffrey Bodenhausen, Sami Jannin, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

Major breakthroughs have recently been reported that can help overcome two inherent drawbacks of NMR: the lack of sensitivity and the limited memory of longitudinal magnetization. Dynamic nuclear polarization (DNP) couples nuclear spins to the large reserv ...

National Academy of Sciences2009

Long-lived States in Multiple-Spin Systems

Geoffrey Bodenhausen, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

Long-lived spin states are excited in molecules featuring more than two isolated coupled spins, including amino acids. The figure shows the exponential recovery with the longest time-constant in aspartic acid, T1max=5.842±0.004 s, and of the decay of the l ...

2009

Measurement of Slow Diffusion Coefficients of Molecules with Arbitrary Scalar Couplings via Long-Lived Spin States

Geoffrey Bodenhausen, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

New experiments are described for the determination of very slow diffusion constants by nuclear magnetic resonance (NMR) using long-lived (singlet) states. These experiments are suitable for molecules or conformations featuring a wide range of J-couplings. ...

2008

Extending the Scope of Singlet-State Spectroscopy

Geoffrey Bodenhausen, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

Different decoupling sequences are tested - using various shaped radio-frequency (RF) pulses - to achieve the longest possible lifetimes of singlet-state populations over the widest possible bandwidths, that is, ranges of offsets and relative chemical shif ...

2007

Molecular Properties Determined from Relaxation of Long-Lived Spin States

Geoffrey Bodenhausen, Riddhiman Sarkar, Paul Romeo Vasos, Puneet Ahuja

The populations of long-lived spin states, in particular, populations of singlet states that are comprised of antisymmetric combinations of product states, ∣αIβS⟩−∣βIαS⟩, are characterized by very long lifetimes because the dipole-dipole interaction betwee ...

2007