Role of Strain and Ligand Effects in the Modification of the Electronic and Chemical Properties of Bimetallic Surfaces

Periodic density functional calculations are used to illustrate how the combination of strain and ligand effects modify the electronic and surface chemical properties of Ni, Pd, and Pt monolayers supported on other transition metals. Strain and the ligand effects are shown to change the width of the surface d band, which subsequently moves up or down in energy to maintain a constant band filling. Chemical properties such as the dissociative adsorption energy of hydrogen are controlled by changes induced in the average energy of the d band by modification of the d-band width

Systematic Computational and Experimental Investigation of Lithium-Ion Transport Mechanisms in Polyester-Based Polymer Electrolytes

Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds via a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials

Orbital interactions and chemical reactivity of metal particles and metal surfaces

A review is presented with 101 refs. on chem. bonding to metal surfaces and small metal particles demonstrating the power of symmetry concepts to predict changes in chem. bonding. Ab-initio calcns. of chemisorption to small particles, as well as semiempirical extended Hueckel calcns. applied to the study of the reactivity of metal slabs are reviewed. On small metal particles, classical notions of electron promotion and hybridization are found to apply. The surroundings of a metal atom (ligands in complexes, other metal atoms at surfaces), affect bonding and reactivity through the prehybridization they induce. A factor specific for large particles and surfaces is the required localization of electrons on the atoms involved in the metal surface bond. At the surface, the bond energy is found to relate to the grou8p orbital local d. of states at the Fermi level. The use of this concept is extensively discussed and illustrated for chemisorption of CO and dissocn. of NO on metal surfaces. A discussion is given of the current decompn. schemes of bond energies and related concepts (exchange (Pauli)-repulsion, polarization, charge transfer). The role of non-orthogonality of fragment orbitals and of kinetic and potential energy for Pauli repulsion and (orbital) polarization is analyzed. Numerous examples are discussed to demonstrate the impact of those concepts on chem. bonding theor

Immuno-metabolic profile of patients with psychotic disorders and metabolic syndrome. Results from the FACE-SZ cohort

Background: Metabolic syndrome (MetS) is a highly prevalent and harmful medical disorder often comorbid with psychosis where it can contribute to cardiovascular complications. As immune dysfunction is a key shared component of both MetS and schizophrenia (SZ), this study investigated the relationship between immune alterations and MetS in patients with SZ, whilst controlling the impact of confounding clinical characteristics including psychiatric symptoms and comorbidities, history of childhood maltreatment and psychotropic treatments. Method: A total of 310 patients meeting DSM-IV criteria for SZ or schizoaffective disorders (SZA), with or without MetS, were systematically assessed and included in the FondaMental Advanced Centers of Expertise for Schizophrenia (FACE-SZ) cohort. Detailed clinical characteristics of patients, including psychotic symptomatology, psychiatric comorbidities and history of childhood maltreatment were recorded and the serum levels of 18 cytokines were measured. A penalized regression method was performed to analyze associations between inflammation and MetS, whilst controlling for confounding factors. Results: Of the total sample, 25% of patients had MetS. Eight cytokines were above the lower limit of detection (LLOD) in more than 90% of the samples and retained in downstream analysis. Using a conservative Variable Inclusion Probability (VIP) of 75%, we found that elevated levels of interleukin (IL)-6, IL-7, IL-12/23 p40 and IL-16 and lower levels of tumor necrosis factor (TNF)-α were associated with MetS. As for clinical variables, age, sex, body mass index (BMI), diagnosis of SZ (not SZA), age at the first episode of psychosis (FEP), alcohol abuse, current tobacco smoking, and treatment with antidepressants and anxiolytics were all associated with MetS. Conclusion: We have identified five cytokines associated with MetS in SZ suggesting that patients with psychotic disorders and MetS are characterized by a specific “immuno-metabolic” profile. This may help to design tailored treatments for this subgroup of patients with both psychotic disorders and MetS, taking one more step towards precision medicine in psychiatry. © 2022 The AuthorsImmuno-Génétique, Inflammation, retro-Virus, Environnement : de l'étiopathogénie des troubles psychotiques aux modèles animauxRéseau d'Innovation sur les Voies de Signalisation en Sciences de la Vi