Publications associées à NMR diffusion and relaxation studies of the encapsulation of fragrances by amphiphilic multiarm star block copolymers

Valence can control the nonexponential viscoelastic relaxation of multivalent reversible gels

Gels made of telechelic polymers connected by reversible cross-linkers are a versatile design platform for biocompatible viscoelastic materials. Their linear response to a step strain displays a fast, near-exponential relaxation when using low-valence cros ...

Amer Assoc Advancement Science2024

Magnetism of Single Surface Adsorbed Atoms Studied with Radio-Frequency STM

Clément Marie Soulard

This thesis investigates the magnetic properties of single atoms and molecules adsorbed on thin magnesium oxide decoupling layers, grown on a silver single crystal. To address these systems experimentally, we use a low temperature scanning tunneling micros ...

EPFL2024

Scaling Description of Dynamical Heterogeneity and Avalanches of Relaxation in Glass-Forming Liquids

Ali Tahaei, Matthieu Wyart

We provide a theoretical description of dynamical heterogeneities in glass-forming liquids, based on the premise that relaxation occurs via local rearrangements coupled by elasticity. In our framework, the growth of the dynamical correlation length e and o ...

American Physical Society2023

Fast, Broad-Band Magnetic Resonance Spectroscopy with Diamond Widefield Relaxometry

Hoda Shirzad, Mayeul Sylvain Chipaux

We present an alternative to conventional Electron the use of bulky magnets and magnetron equipment, we use the photoluminescence of an ensemble of Nitrogen-Vacancy centers at the surface of a diamond. Monitoring their relaxation time (or T1), we detected ...

AMER CHEMICAL SOC2023

Dynamic nuclear polarisation of 1H in Gd-doped In(OH)3

David Lyndon Emsley, Michael Allan Hope, Amrit Venkatesh, Yuxuan Zhang

Dynamic nuclear polarisation (DNP) of solids doped with high-spin metal ions, such as Gd3+, is a useful strategy to enhance the nuclear magnetic resonance (NMR) sensitivity for these samples. Spin diffusion can relay polarisation throughout a sample, which ...

Academic Press Inc - Elsevier Science2023

Deuterated TEKPol Biradicals and the Spin-Diffusion Barrier in MAS DNP

Dominik Józef Kubicki, David Lyndon Emsley, Yu Rao, Amrit Venkatesh, Federico De Biasi

The sensitivity of NMR spectroscopy is considerably enhanced by dynamic nuclear polarization (DNP). In DNP polarization is transferred from unpaired electrons of a polarizing agent to nearby proton spins. In solids, this transfer is followed by the transpo ...

Wiley-VCH Verlag GmbH2023

Robust gamma-aminobutyric acid and energy metabolism measurements by proton and phosphorus magnetic resonance spectroscopy and fingerprinting

Songi Lim

Magnetic resonance spectroscopy (MRS) is the only technique that can detect endogenous metabolites directly and non-invasively in vivo. It allows to identify different metabolites and analyze the dynamic neurochemical processes in the brain, skeletal muscl ...

EPFL2023

Diffusion timescale conundrum in contact metamorphism: Oxygen isotope and trace element profiles in dolomite

Lukas Baumgartner, Anders Meibom, Stéphane Laurent Escrig, Florence Bégué

Successful application of diffusion chronometry is based on detailed knowledge of diffusion parameters obtained from laboratory experiments, which also need to be upscaled to be applied to natural samples. While generally applicable, several examples of di ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Atomic scale volume and grain boundary diffusion elucidated by in situ STEM

Johann Michler, Amit Sharma, Laszlo Pethö, Xavier Maeder

Diffusion is one of the most important phenomena studied in science ranging from physics to biology and, in abstract form, even in social sciences. In the field of materials science, diffusion in crystalline solids is of particular interest as it plays a p ...

Nature Portfolio2023

Nonparametric estimation for SDE with sparsely sampled paths: An FDA perspective

Victor Panaretos, Neda Mohammadi Jouzdani

We consider the problem of nonparametric estimation of the drift and diffusion coefficients of a Stochastic Differential Equation (SDE), based on n independent replicates {Xi(t) : t is an element of [0 , 1]}13 d B(t), where alpha is an element of {0 , 1} a ...

Elsevier2024

A diamond spin qubit scanning probe microscope

Dinesh Kevin Mathais Pinto

The properties of a physical system only exist in relation to its environment. This thesis presents the development of a novel spin qubit scanning probe microscope operating over a wide range of environmental conditions. The qubit, which sits at the heart ...

EPFL2023

H-1 Detected Relayed Dynamic Nuclear Polarization

David Lyndon Emsley, Pierrick Berruyer, Andrea Bertarello, Moreno Lelli

Recently, it has been shown that methods based on the dynamics of 1 H nuclear hyperpolarization in magic angle spinning (MAS) NMR experiments can be used to determine mesoscale structures in complex materials. However, these methods suffer from low sensiti ...

2022

Magnetic Resonance and Hyperpolarization Methods for Perovskite Photovoltaics

Aditya Mishra

Solid-state NMR can provide information about the atomic-level microstructure and dynamics in materials as it directly probes the local nuclear environment. In the last decade, halide perovskites have drawn intense interest because of their intriguing opto ...

EPFL2022

Simulating Microswimmers Under Confinement With Dissipative Particle (Hydro) Dynamics

Ignacio Pagonabarraga Mora

In this work we study microwimmers, whether colloids or polymers, embedded in bulk or in confinement. We explicitly consider hydrodynamic interactions and simulate the swimmers via an implementation inspired by the squirmer model. Concerning the surroundin ...

FRONTIERS MEDIA SA2022

Oxygen diffusion in garnet: Experimental calibration and implications for timescales of metamorphic processes and retention of primary O isotopic signatures

Anders Meibom, Stéphane Laurent Escrig

Knowledge of oxygen diffusion in garnet is crucial for a correct interpretation of oxygen isotope signatures in natural samples. A series of experiments was undertaken to determine the diffusivity of oxygen in garnet, which remains poorly constrained. The ...

MINERALOGICAL SOC AMER2022

Hyperpolarization of inorganic solids

Snaedis Björgvinsdóttir

Solid-state NMR can provide information about the atomic level structure and dynamics of materials. It directly probes symmetry and structure at nuclear sites, and is especially useful for investigation of disordered or amorphous solids that lack long rang ...

EPFL2020

Non-exponential magnetic relaxation in magnetic nanoparticles for hyperthermia

Ferenc Simon, Bence Gábor Márkus

Magnetic nanoparticle based hyperthermia emerged as a potential tool for treating malignant tumours. The efficiency of the method relies heavily on the knowledge of magnetic properties of the samples; in particular, knowledge of the frequency dependent com ...

2021

Endogenous O-17 Dynamic Nuclear Polarization of Gd-Doped CeO2 from 100 to 370 K

David Lyndon Emsley, Snaedis Björgvinsdóttir, Georges Guévork Jean-Jacques Menzildjian, Michael Allan Hope, Bowen Zhang, Moreno Lelli, Zhuoran Wang

O-17 NMR is an invaluable tool to study the structure and dynamics of oxide materials but remains challenging to apply in many systems. Even with isotopic enrichment, studies of samples with low masses and/or concentrations of the active species, such as t ...

2021

A Strategy to Conjugate Bioactive Fragments to Cytotoxic Diiron Bis(cyclopentadienyl) Complexes

Paul Joseph Dyson, Mouna Hadiji, Silvia Schoch, Sarah Alexandra Pais Pereira

A series of bioactive molecules were synthesized from the condensation of aspirin or chlorambucil with terminal alkynes bearing alcohol or amine substituents. Insertion of the resulting alkynes into the iron-carbyne bond of readily accessible diiron bis(cy ...

AMER CHEMICAL SOC2021

Scaling analyses for hyperpolarization transfer across a spin-diffusion barrier and into bulk solid media

Arthur César Pinon, David Lyndon Emsley, Bradley Floyd Chmelka

By analogy to heat and mass transfer film theory, a general approach is introduced for determining hyperpolarization transfer rates between dilute electron spins and a surrounding nuclear ensemble. These analyses provide new quantitative relationships for ...

2021