Recherche

Afficher tous les résultats pour

Accueil

Personne

Sami Jannin

Cette personne n’est plus à l’EPFL

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (61)

Low-temperature cross polarization in view of enhancing dissolution Dynamic Nuclear Polarization in NMR

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet

Dynamic Nuclear Polarization (DNP) induced by saturation of ESR transitions of TEMPO at 1.2 K and 3.35 T is characterized by build-up rates that are typically 5 times faster for protons than for the carboxylic carbon-13 in acetate. We show that cross polar ...

Elsevier2011

Ultra High-Resolution NMR: Sustained Induction Decays of Long-Lived Coherences

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet

Long-lived coherences (LLCs) in homonuclear pairs of chemically inequivalent spins can be excited and sustained during protracted radio frequency irradiation periods that alternate with brief windows for signal observation. Fourier transformation of the su ...

2011

A spinning thermometer to monitor microwave heating and glass transitions in dynamic nuclear polarization

Geoffrey Bodenhausen, Sandrine Gerber, Sami Jannin, Pascal Miéville, Marc Anthony Caporini

As previously demonstrated by Thurber and Tycko, the peak position of Br-79 in potassium bromide (KBr) allows one to determine the temperature of a spinning sample. We propose to adapt the original design by using a compact KBr tablet placed at the bottom ...

Wiley-Blackwell2011

Three-field NMR to preserve hyperpolarized proton magnetization as long-lived states in moderate magnetic fields

Geoffrey Bodenhausen, Sami Jannin, Aurélien Bornet

This communication describes a three-field experiment where inequivalent scalar coupled spin pairs are hyperpolarized at 3.35 T and 1.2 K by dynamic nuclear polarization (DNP), rapidly transferred to high field (7 T) to prepare a suitable initial condition ...

Elsevier2011

Method for nmr spectrometry or mri measurement using dissolution dynamic nuclear polarization (dnp) with scavenging of free radicals

Geoffrey Bodenhausen, Sami Jannin, Pascal Miéville

PROBLEM TO BE SOLVED: To provide a method for extending longitudinal relaxation time and transverse relaxation time in nuclear magnetic resonance (NMR), while removing free radicals from hyperpolarized solution. SOLUTION: A method for preparing samples for ...

2011

Fractional Spin-Labeling of Polymers for Enhancing NMR Sensitivity by Solvent-Free Dynamic Nuclear Polarization

Andrzej Sienkiewicz, Geoffrey Bodenhausen, Sandrine Gerber, Sami Jannin, Françoise Borcard, Pascal Miéville, Marc Anthony Caporini

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

Feasibility of in vivo N-15 MRS detection of hyperpolarized N-15 labeled choline in rats

Arnaud Comment, Rolf Gruetter, Sami Jannin, Ruud van Heeswijk, Fiodar Kurdzesau, Cristina Ramona Cudalbu

The increase of total choline in tumors has become an important biomarker in cancer diagnosis. Choline and choline metabolites can be measured in vivo and in vitro using multinuclear MRS. Recent in vivo C-13 MRS studies using labeled substrates enhanced vi ...

2010

Kinetics of Yttrium-Ligand Complexation Monitored Using Hyperpolarized 89Y as a Model for Gadolinium in Contrast Agents

Geoffrey Bodenhausen, Lothar Helm, Sami Jannin, Pascal Miéville

Hyperpolarization by dissolution dynamic nuclear polarization (DNP) enhances Y-89 spin magnetization by 3 to 4 orders of magnitude and provides a way to monitor yttrium-ligand complexation "on the fly" by means of Y-89 NMR. In this communication, we show a ...

American Chemical 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

Dynamic nuclear polarization techniques for magnetic resonance imaging and particles targets experiments

Sami Jannin

Within a collaboration with the Sample Environment and Polarised Targets (SEPT) group at Paul Scherrer Institut (PSI), we developed two Dynamic Nuclear Polarization (DNP) machines operating at ~ 1 K. The first one is working at an electron spin resonance f ...

EPFL2009

Hyperpolarized Lithium-6 as a Sensor of Nanomolar Contrast Agents

Arnaud Comment, Jacques Van Der Klink, Chiara Perazzolo, Rolf Gruetter, Sami Jannin, Ruud van Heeswijk, Fiodar Kurdzesau, Cristina Ramona Cudalbu

Lithium is widely used in psychotherapy. The Li-6 isotope has a long intrinsic longitudinal relaxation time T-1 on the order of minutes, making it an ideal candidate for hyperpolarization experiments. In the present study we demonstrated that lithium-6 can ...

Wiley-Blackwell2009

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

Proton NMR of15N-choline metabolites enhanced by dynamic nuclear polarization

Arnaud Comment, Geoffrey Bodenhausen, Rolf Gruetter, Sami Jannin, Riddhiman Sarkar, Paul Romeo Vasos

(Figure Presented) Chemical shifts of protons can report on metabolic transformations such as the conversion of choline to phosphocholine. To follow such processes in vivo, magnetization can be enhanced by dynamic nuclear polarization (DNP). We have hyperp ...

2009

Dynamic nuclear polarization of small labelled molecules in frozen water-alcohol solutions

Arnaud Comment, Jacques Van Der Klink, Sami Jannin, Fiodar Kurdzesau

In recent years methods of creating 'hyperpolarized' substances have gained considerable attention in biomedical magnetic resonance and dynamic nuclear polarization (DNP) is one of the most promising, especially for imaging applications. Here we present re ...

2008

A 140 GHz prepolarizer for dissolution dynamic nuclear polarization

Arnaud Comment, Jacques Van Der Klink, Sami Jannin, Fiodar Kurdzesau

Apart from their very classical use to build polarized targets for particle physics, the methods of dynamic nuclear polarization (DNP) have more recently found application for sensitivity enhancement in high-resolution NMR, both in the solid and in the liq ...

2008

In Vivo Detection of Hyperpolarized 15N Choline in the Rat

Arnaud Comment, Chiara Perazzolo, Rolf Gruetter, Sami Jannin, Ruud van Heeswijk, Fiodar Kurdzesau, Cristina Ramona Cudalbu

2008

Principles of operation of a DNP prepolarizer coupled to a rodent MRI scanner

Arnaud Comment, Jacques Van Der Klink, Rolf Gruetter, Sami Jannin, Fiodar Kurdzesau

A dynamic nuclear polarization prepolarizer was developed and coupled to a 9.4 T rodent magnetic resonance imaging scanner in order to perform in vivo hyperpolarization experiments. In the present paper, emphasis is put on methods and hardware performance ...

2008

Producing over 100 ml of highly concentrated hyperpolarized solution by means of dissolution DNP

Arnaud Comment, Jacques Van Der Klink, Sami Jannin, Ruud van Heeswijk, Fiodar Kurdzesau

New low-temperature inserts compatible with an existing hyperpolarizer were developed to dynamically polarize nuclei in large samples. The performance of the system was tested on 8 ml glassy frozen solutions containing 13C-labeled molecules and doped with ...

Academic Press Inc - Elsevier Science2008

Design and performance of a DNP prepolarizer coupled to a rodent MRI scanner

Arnaud Comment, Jacques Van Der Klink, Rolf Gruetter, Sami Jannin, Fiodar Kurdzesau

For most of the last forty years, the techniques of Dynamic Nuclear Polarization (DNP) have been confined to particle-physics laboratories building polarized targets, but recently it has been shown that samples similar to a solid target can be transformed ...

2007

Page 3 sur 4