Publications associées à Disentangling oil weathering using GCxGC. 2. Mass transfer calculations

Innovative Biomarkers for Obesity and Type 1 Diabetes Based on Bifidobacterium and Metabolomic Profiling

Stephan Morgenthaler, Paul Refinetti, Mariya Yuryevna Skvortsova

The role of Bifidobacterium species and microbial metabolites such as short-chain fatty acids (SCFAs) and human milk oligosaccharides in controlling intestinal inflammation and the pathogenesis of obesity and type 1 diabetes (T1D) has been largely studied ...

MDPI2024

Neurobiological and metabolic basis of motivation and effort-based decision-making - A human 1H-MRS, fMRI and machine learning study

Arthur Barakat

Motivation is a multifaceted phenomenon that we explore within the framework of decision-making. Through this cognitive process, actions are directed towards specific goals by performing a trade-off between the cost and benefit of an action. The dorsomedia ...

EPFL2024

Advancing Glycan Analysis: Cryogenic Ion Spectroscopy for Database-Driven Identification

Ali H Abikhodr

Glycans play a pivotal role in both physiological processes; however, the field of glycobiology remains relatively understudied within biochemistry. The intricate complexity of glycans, coupled with their abundance of isomeric forms, presents formidable ch ...

EPFL2023

Using Hadamard Transform Multiplexed IR Spectroscopy Together with a Segmented Ion Trap for the Identification of Mobility-Selected Isomers

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Ali H Abikhodr, Vasyl Yatsyna

The high isomeric complexity of glycans makes them particularly difficult to analyze. While ultra-high-resolution ion mobility spectrometry(IMS) can offer rapid baseline separation of many glycan isomers,their unambiguous identification remains a challengi ...

2023

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

Fragment ion-functional group relationships in organic aerosols using aerosol mass spectrometry and mid-infrared spectroscopy

Satoshi Takahama, Nikunj Dudani, Amir Yazdani, Imad El Haddad

Aerosol mass spectrometry (AMS) and mid-infrared spectroscopy (MIR) are two analytical methods for characterizing the chemical composition of OM. While AMS provides high-temporal-resolution bulk measurements, the extensive fragmentation during the electron ...

2022

Chemical characterization of organic aerosols with a focus on biomass burning and mid-infrared spectroscopy

Amir Yazdani

Aerosols play a significant role in the atmosphere through affecting the radiative budget, cloud condensation nuclei activity, and visibility. They also cause adverse health effects leading to premature deaths. A major fraction of aerosols is organic matte ...

EPFL2022

High-frequency gaseous and particulate chemical characterization using extractive electrospray ionization mass spectrometry (Dual-Phase-EESI-TOF)

Andrea Baccarini, Houssni Lamkaddam, Imad El Haddad, Mihnea Surdu

To elucidate the sources and chemical reaction pathways of organic vapors and particulate matter in the ambient atmosphere, real-time detection of both the gas and particle phase is needed. State-of-the-art techniques often suffer from thermal decompositio ...

COPERNICUS GESELLSCHAFT MBH2022

Standard-Free Quantification of Dicarboxylic Acids: Case Studies with Salt-Rich Effluents and Serum

Christian Ludwig, Daniil Salionov, Sasa Bjelic

The present study evaluates the ionization efficiency (IE) of linear and branched C2–C14 dicarboxylic acids (DCAs) by electrospray ionization (ESI) under different conditions. The influence of the concentration of organic modifier (MeOH); mobile phase addi ...

2022

Surface Analysis by Secondary Ion Mass Spectrometry (SIMS): Principles and Applications from Swiss Laboratories

Thomas Bovay, Lukas Baumgartner, Anders Meibom, Stéphane Laurent Escrig, Florent Olivier Vivien Plane

Secondary Ion Mass Spectrometry (SIMS) extracts chemical, elemental, or isotopic information about a localized area of a solid target by performing mass spectrometry on secondary ions sputtered from its surface by the impact of a beam of charged particles. ...

SWISS CHEMICAL SOC2022

Low-energy Electron Holography Microscope for Imaging of Single Molecules

Sven Alexander Szilagyi

Structure determination techniques are an essential tool to investigate and understand molecules, especially in biology, where functionality crucially depends on structure. The dominant high-resolution methods, such as transmission electron microscopy and ...

EPFL2022

Identification of Isomeric Biomolecules by Infrared Spectroscopy of Solvent-Tagged Ions

Oleg Boyarkine, Andrei Zviagin

The difference in functionality of many isomeric biomolecules requires their analytical identification for life science studies. We present a universal approach for quantitative identification of different small- to medium-sized isomeric biomolecules that ...

AMER CHEMICAL SOC2022

Gentle nano-electrospray ion source for reliable and efficient generation of microsolvated ions

Oleg Boyarkine, Vladimir Kopysov, Andrei Zviagin

We present herein the design of a nano-electrospray ion source capable of reliable generation of large quantities of microsolvated ions. The source is based on a triple molecular skimmer scheme and can be quickly tuned to generate bare ions or their ionic ...

AIP Publishing2022

Cryo-EM structure of native human thyroglobulin

Henning Paul-Julius Stahlberg

The thyroglobulin (TG) protein is essential to thyroid hormone synthesis, plays a vital role in the regulation of metabolism, development and growth and serves as intraglandular iodine storage. Its architecture is conserved among vertebrates. Synthesis of ...

Nature Research2022

Constraining the response factors of an extractive electrospray ionization mass spectrometer for near-molecular aerosol speciation

Yandong Tong, Julia Schmale, Imad El Haddad

Online characterization of aerosol composition at the near-molecular level is key to understanding chemical reaction mechanisms, kinetics, and sources under various atmospheric conditions. The recently developed extractive electrospray ionization time-of-f ...

2021

Multiphase transport and evaporative cooling in fuel cell gas diffusion layers

Sarah van Rooij

The use of evaporative cooling in the gas diffusion layer (GDL) of polymer electrolyte fuel cells has been proposed as a simple yet impactful solution to simultaneously provide the functionality of cell cooling, thanks to the dissipation of the latent heat ...

EPFL2021

Modelling and process optimization for biodiesel production from Nannochloropsis salina using artificial neural network

Edgard Gnansounou

In the present investigation, calcium oxide solid nanocatalyst derived from the egg shell and Nannochloropsis salina were used for the production of biodiesel. The morphological characteristics and functional groups of synthesized nanocatalyst was characte ...

Elsevier2021

Nighttime chemistry of biomass burning emissions in urban areas: A dual mobile chamber study

Athanasios Nenes, Spyros Pandis

Residential biomass burning for heating purposes is an important source of air pollutants during winter. Here we test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through oxidation of the emi ...

Copernicus GmbH2021

A gas phase approach for glycan analysis: Combining ultrahigh-resolution ion mobility spectrometry with cryogenic vibrational spectroscopy

Ahmed Ben Faleh

The last decades have been punctuated by the development of revolutionary analytical technologies that have enabled the analysis of biomolecular structures and unraveled the roles they play in biological systems. However, certain classes of biomolecules re ...

EPFL2021

An Experimental Setup for Heterogeneous Catalysis on Atomically Defined Metal Nanostructures

Jean-Guillaume De Groot

The main objective of this PhD thesis is to link the atomic scale structure to the catalytic properties of self-assembled nanostructures. The growth and characterization of these nanostructures was carried out in an ultra-high vacuum (UHV) chamber initiall ...

EPFL2021