Thomas Meyer

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Abstract We recently discovered increased expression of a cytoplasmic long noncoding RNA, lnc-FANCI-2, coinciding with cervical lesion progression from CIN1, CIN2-3 to cervical cancer.

Abstract Patients with an implantable cardioverter-defibrillator (ICD) often report psychological distress.

Substance Use Disorder (SUD) contributes to the early onset of age-related diseases and mortality. Although Accelerated Aging (AA) in people with SUD (pSUD) is a key factor in these outcomes, as indicated by changes in Epigenetic Clocks (EC), existing assessments of AA in pSUD primarily utilize ECs designed for non-brain tissues.

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Abstract We recently discovered increased expression of a long noncoding RNA, lnc-FANCI-2, coinciding with cervical lesion progression from CIN1, CIN2-3 to cervical cancer.

Abstract: The KLM approach to defeasible reasoning introduces a weakened form of implication into classical logic.

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Today, most of the commercially available Li-ion batteries use liquid electrolyte (a lithium salt dissolved in an organic solvent). Substituting liquid electrolyte by a solid-state one is considered as a highly promising way to increase electrochemical performances and safety of the next lithium battery generation. Indeed, composite solid-state electrolytes are designed to combine the positive features of polymer and ionic conductive ceramic electrolytes. Improving their critical properties such as ionic conductivity and processability is a crucial step required to be competitive with liquid electrolytes.My work focuses on understanding Li+ ions diffusion mechanisms occurring within solid-state electrolytes composed of poly(ethylene oxide) containing lithium bis(trifluoromethanesulfonyl)imide as lithium salt, and the garnet-type ceramic (Li6.4La3Zr1.4Ta0.6O12). To study lithium mobility, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and high-resolution solid-state nuclear magnetic resonance (ssNMR) are two complementary advanced techniques allowing studies based on lithium isotopic tracing. A chemical analysis by ToF-SIMS allows to determine at the surface 6Li isotopic abundance from intensities of 6Li+ and 7Li+ fragments at sub-micrometric scale. On the other hand, by probing the chemical environments of 6Li and 7Li nuclei by ssNMR allows to estimate 6Li abundance in bulk by combining 6Li and 7Li absolute integrals. Furthermore, lithium quantification is possible by using ssNMR. In this work, ToF-SIMS and ssNMR are combined together to develop robust methodologies based on the study of polymer electrolytes prepared with various 6Li abundances. Both data acquisition conditions and data processing are optimised, allowing 6Li abundance estimation of a solid lithiated material with a high precision of 1% and 2%, respectively.These methodologies are implemented to characterise Li+ ions diffusion (including self-diffusion) after applying a chronoamperometry or a chronopotentiometry (CP) sequence at 60° C on electrochemical systems. They are based on two geometries growing in complexity, namely in-plane and sandwich. A positive electrode in lithium enriched at 95.4% in 6Li and a negative electrode in lithium at natural isotopic abundance (7.6% of 6Li ) are used. The 6Li-foil induces 6Li+ ions diffusion throughout the device already containing lithium at natural isotopic abundance., Lithium dynamics effects can be investigated by detecting both isotopes. ssNMR characterisations prove that, after applying a CP sequence, 6Li+ ions diffuse throughout all the layers of a sandwich device because 6Li abundance estimation is higher than 6Li natural abundance. Finally, Li+ ions diffusion is thoroughly studied throughout a third device composed of a polymer electrolyte matrix containing a dispersion of ceramic particles. Such composite electrolyte could be implemented in commercial solid-state batteries. According to ssNMR characterisations, ceramic particles have a greater 6Li content than the polymer electrolyte matrix after applying a CP sequence. Furthermore, models of lithium isotopic exchanges are described. They take into account continuity equations solving non-equilibrium transport under voltage, and electrochemical transfers at interfaces. Implementing experimental results into numerical simulations enable to extract critical parameters such as Li+ ions self-diffusion coefficient in solid-state electrolytes or lithium transfer properties at interfaces. With the help of relevant physical models, strategies can be developed to improve solid-state electrolyte design.All these results obtained by using lithium isotopic tracing illustrate the strengths of the methodologies presented in this work. They provide new keys to a better understanding of Li+ ions diffusion pathways in these complex devices. Methodologies may also be adapted to investigate lithium dynamics in solid materials for other applications.