Publications by Christophe Roussel

Heterogeneous Overhauser-DNP on H-1 dominated by scalar coupling in aqueous solution

Jean-Philippe Ansermet, Christophe Roussel, Jonas Milani, Felipe Andres Saenz Padilla

The Overhauser Dynamic Nuclear Polarization (O-DNP) of H-1 nuclei usually involves a dipolar coupling with the polarizing agent, whereas scalar coupling via hyperfine interactions are more common with C-13 nuclei. Here, we show a scalar-coupling dominated ...

WILEY2022

Blatter-type radicals as polarizing agents for electrochemical overhauser dynamic nuclear polarization

Jean-Philippe Ansermet, Christophe Roussel, Jonas Milani, Holger Frauenrath, Felipe Andres Saenz Padilla, Mika Antero Tamski

Overhauser dynamic nuclear polarization (O-DNP) refers to a microwave-assisted process where an unpaired electron's (e.g. a radical) spin polarization is transferred to surrounding nuclei in solution, thus increasing the nuclear magnetic resonance (NMR) si ...

Royal Society of Chemistry2022

Method for the preparation of a sample comprising highly polarized nuclear spins and uses and devices for such a method

Jean-Philippe Ansermet, Christophe Roussel, Jonas Milani, Mika Antero Tamski

Method for the preparation of a sample comprising highly polarized nuclear spins, comprising at least the following steps: a) bringing a polarization system, which using an electrochemical reaction can be converted into an EPR-active radical form thereof, ...

2021

Spin-dependent charge transfer at chiral electrodes probed by magnetic resonance

Jean-Philippe Ansermet, Christophe Roussel, Felix Blumenschein, Mika Antero Tamski

Chirality-induced spin selectivity is evidenced by exciting the spin resonance of radicals in an electrochemical cell where the working electrode is covered with a chiral self-assembled monolayer. Because the electron transfer to and from the paramagnetic ...

ROYAL SOC CHEMISTRY2020

Stabilization of p-GaAs electrode surfaces in organic solvent by bi-phenyl rings for spin dependent electron transfer studies

Jean-Philippe Ansermet, Christophe Roussel, Mika Antero Tamski

Biphenyl-4-thiol (B4t) functionalised p-GaAs photocathodes were compared to non-functionalised p-GaAs ones in the presence of methyl viologen cation radical (MV+•) as a redox mediator. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS ...

2020

Optimization of a Py-GC/MS method for silicone -based lubricants analysis

Christophe Roussel, Céline Burnier

Condom evidence can be analysed using several analytical techniques, such as FTIR, MALDI-MS or DART-TOF-MS, but the only one that was used on real samples for transfer and persistence studies in the context of sexual assault or rape cases was Py-GC/MS. How ...

2020

Electrochemical Overhauser dynamic nuclear polarization

Jean-Philippe Ansermet, Christophe Roussel, Jonas Milani, Mika Antero Tamski

Nuclear Magnetic Resonance (NMR) spectroscopy suffers from low sensitivity due to the low nuclear spin polarization obtained within practically achievable external magnetic fields. Dynamic Nuclear Polarization (DNP) refers to techniques that increase the N ...

2020

Quantification of THC in Cannabis plants by fast-HPLC-DAD: A promising method for routine analyses

Christophe Roussel, Céline Burnier

Nowadays, Gas Chromatography Mass Spectrometry (GC-MS) is mainly used in forensic sciences but suffers from limitations when the analysed compounds are thermally instable as it is the case for THC-A (Tetrahydrocannabinolic Acid) which is converted into Del ...

ELSEVIER SCIENCE BV2019

Probing charge transfer processes at p-GaAs electrodes under weak optical excitation

Jean-Philippe Ansermet, Christophe Roussel, Felix Blumenschein, Mika Antero Tamski

The p-GaAs photocathode/acetonitrile interface was characterised in the dark and with tens of mu W/cm(2) laser powers at 830 nm wavelength, using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Two redox mediators were used that p ...

2019

Thermal annihilation of photo-induced radicals following dynamic nuclear polarization to produce transportable frozen hyperpolarized 13C-substrates

Arnaud Comment, Giovanni Boero, Christophe Roussel, Tian Cheng, Andrea Capozzi

Hyperpolarization via dynamic nuclear polarization (DNP) is pivotal for boosting magnetic resonance imaging (MRI) sensitivity and dissolution DNP can be used to perform in vivo real-time 13C MRI. The type of applications is however limited by the relativel ...

Nature Publishing Group2017

Experimental and theoretical studies on electropolymerization of polar amino acids on platinum electrode

Christophe Roussel

The anodic oxidation of polar amino acids (L-serine, L-threonine, L-asparagine, and L-glutamine) in aqueous electrolyte on smooth platinum electrode was carried out by cyclic voltammetry coupled to electrochemical quartz crystal microbalance (EQCM). pH (zw ...

Elsevier2017

Preparation, kinetics, mechanism and properties of semi-transparent photocatalytic stable films active in dye degradation

Juan Kiwi, César Pulgarin, Christophe Roussel, Laura Victoria Suárez Murillo

The photocatalytic activity, mechanism and characterization of polyethylene-TiO2 films (PE-TiO2) during the discoloration/degradation of methylene blue (MB) are reported in this study. PE-TiO2 films were prepared at moderate temperatures (similar to 90 deg ...

Elsevier2016

Method for the generation of radicals for dynamic nuclear polarization and uses thereof for nmr, mrs and mri

Arnaud Comment, Christophe Roussel, Tim Rolf Eichhorn

A method for the preparation of a sample comprising highly polarized nuclear spins is proposed, comprising at least the following steps: a) provision of molecules with 1,2-dione structural units and/or molecules with 2,5-diene-1,4-dione structural units in ...

2016

Optimal Glass-Forming Solvent Brings Sublimation Dynamic Nuclear Polarization to 129Xe Hyperpolarization Biomedical Imaging Standards

Arnaud Comment, Christophe Roussel, Jean-Noël Hyacinthe, Andrea Capozzi

In addition to the dedicated spin exchange optical pumping (SEOP) technique, an alternative method to produce hyperpolarized xenon gas using dynamic nuclear polarization (DNP) followed by a sublimation procedure was proposed. The challenge associated with ...

American Chemical Society2015

Photoinduced Nonpersistent Radicals as Polarizing Agents for X-Nuclei Dissolution Dynamic Nuclear Polarization

Arnaud Comment, Jacques Van Der Klink, Giovanni Boero, Christophe Roussel, Tian Cheng, Tim Rolf Eichhorn, Jean-Noël Hyacinthe, Andrea Capozzi

Hyperpolarization via dissolution dynamic nuclear polarization (DNP) is a versatile method to dramatically enhance the liquid-state NMR signal of X-nuclei and can be used for performing metabolic and molecular imaging. It was recently demonstrated that ins ...

American Chemical Society2015

Standard addition strip for quantitative electrostatic spray ionization mass spectrometry analysis: Determination of caffeine in drinks

Hubert Girault, Christophe Roussel, Liang Qiao, Elena Tobolkina

Standard addition strips were prepared for the quantitative determination of caffeine in different beverages by electrostatic spray ionisation mass spectrometry (ESTASI-MS). The gist of this approach is to dry spots of caffeine solutions with different con ...

Elsevier2014

RF-plasma pretreatment of surfaces leading to TiO2 coatings with improved optical absorption and OH-radical production

Juan Kiwi, César Pulgarin, Christophe Roussel, Oualid Baghriche, Sami Rtimi

Evidence is presented for the RF pretreatment of polyester enhances the TiO2 coating generation of oxidative species/radicals under a low level actinic light irradiation. After 30 min RF-plasma pretreatment of the polyester samples, the fastest bacterial i ...

Elsevier2013

RF-plasma pretreatment of surfaces leading to TiO2 coatings with improved optical absorption and OH-radical production (vol 130, pg 65, 2013)

Juan Kiwi, César Pulgarin, Christophe Roussel, Oualid Baghriche, Sami Rtimi

Elsevier2013

Hyperpolarization of 129Xe by sublimation DNP using photo-activated radical precursors

Arnaud Comment, Christophe Roussel, François Lazeyras, Tim Rolf Eichhorn, Jean-Noël Hyacinthe, Najat Salameh, Andrea Capozzi

2013

Hyperpolarization without persistent radicals for in vivo real-time metabolic imaging

Arnaud Comment, Christophe Roussel, Mor-Miri Mishkovsky, Tian Cheng, Tim Rolf Eichhorn, Yuhei Takado, Jean-Noël Hyacinthe, Najat Salameh, Andrea Capozzi

Hyperpolarized substrates prepared via dissolution dynamic nuclear polarization have been proposed as magnetic resonance imaging (MRI) agents for cancer or cardiac failure diagnosis and therapy monitoring through the detection of metabolic impairments in v ...

National Academy of Sciences2013