À ma famille passée, présente et future 5 Table of contents Abbreviations 6 Abstract 7 Publication list 8 Introduction 9 Stable isotopes 11 General considerations 11 Definitions 12 Mechanisms of isotope fractionation 13 1) Physical fractionations 13 2) Chemical fractionations 14 Isotopomers 16 Measurements of isotope and isotopomer abundance 17 1) IRMS 17 3) FTIR 19 2) NMR 19 Climate change 23 ...

Many upcoming and proposed missions to ocean worlds such as Europa, Enceladus, Titan aim evaluate their habitability the existence of potential life on these moons. These will suffer from communication challenges technology limitations. We review investigate applicability data science unsupervised machine learning (ML) techniques isotope ratio mass spectrometry (IRMS) volatile laboratory analog...

Rationale Ecologists increasingly determine the ?15N values of amino acids (AA) in animal tissue; “source” AA typically exhibit minor variation between diet and consumer, while “trophic” have increased consumers. Thus, trophic-source offsets (i.e., ?15NT-S) reflect trophic position a food web. However, even variations ?15Nsource may influence magnitude offset that represents step, known as disc...

Rationale Sulfur isotope analysis of organic sulfur-containing molecules has previously been hindered by challenging preparatory chemistry and analytical requirements for large sample sizes. The natural-abundance sulfur isotopic compositions the amino acids, cysteine methionine, have therefore not yet investigated despite potential utility in biomedicine, ecology, oceanography, biogeochemistry,...

Rationale The dual isotope ratio analysis, carbon (?13C value) and hydrogen (?2H value), of methane (CH4) is a valuable tracer tool within range areas scientific investigation, not least wetland ecology, microbiology, CH4 source identification the tracing geological leakages thermogenic in groundwater. Traditional methods collecting, purification, separating analysing for ?13C ?2H determination...

Stable isotope tracer methodologies are becoming increasingly widespread in metabolic research; yet a number of factors restrict their implementation, such as, i.v infusions, multiple cannulae, tissue samples, and significant cost. We recently validated the sensitivity of the orally administered stable isotope tracer deuterium oxide (D2O) for quantifying day-to-day changes in muscle protein syn...