Static and dynamic structure of monomers, dimers and trimers of HgCl2 from density-functional calculations

We report relativistic density-functional calculations for the equilibrium structures and the vibrational frequencies of the (HgCl2)n molecules with n = 1 to 3, as part of a broad exploration of the potential energy landscape of these compounds that will later be used to develop their pseudoclassical interatomic force laws. The calculations are carried out both in a physical plane-waves-expansion approach and in a quantum-chemical localized-Gaussians-expansion approach, with mutually consistent results within their expected accuracy, and are supplemented by analysis of the bond type and of the valence-electrons localization. The relativistic results are also compared with those of analogous non-relativistic calculations. For the monomer and the dimer we find close agreement with the earlier results of Kaupp and von Schnering and of Donald, Hargittai and Hoffmann, and in particular for the mechanical-equilibrium shape of the dimer we confirm their prediction of a major symmetry-breaking distortion driven by relativistic effects. We find an analogous relativistic structural distortion for the trimer, leading to alternative mechanical-equilibrium shapes that can all be viewed as resulting from the direct addition of a monomer to a dimer. The basic ground-state structures of the trimer clearly are precursors to the unique crystal structure of HgCl2 as a lamellar crystal formed from stripes of Cl-Hg-Cl molecules

In silico validation of the autoinflammatory disease damage index

INTRODUCTION: Autoinflammatory diseases can cause irreversible tissue damage due to systemic inflammation. Recently, the Autoinflammatory Disease Damage Index (ADDI) was developed. The ADDI is the first instrument to quantify damage in familial Mediterranean fever, cryopyrin-associated periodic syndromes, mevalonate kinase deficiency and tumour necrosis factor receptor-associated periodic syndrome. The aim of this study was to validate this tool for its intended use in a clinical/research setting. METHODS: The ADDI was scored on paper clinical cases by at least three physicians per case, independently of each other. Face and content validity were assessed by requesting comments on the ADDI. Reliability was tested by calculating the intraclass correlation coefficient (ICC) using an 'observer-nested-within-subject' design. Construct validity was determined by correlating the ADDI score to the Physician Global Assessment (PGA) of damage and disease activity. Redundancy of individual items was determined with Cronbach's alpha. RESULTS: The ADDI was validated on a total of 110 paper clinical cases by 37 experts in autoinflammatory diseases. This yielded an ICC of 0.84 (95% CI 0.78 to 0.89). The ADDI score correlated strongly with PGA-damage (r=0.92, 95%\u2009CI 0.88 to 0.95) and was not strongly influenced by disease activity (r=0.395, 95%\u2009CI 0.21 to 0.55). After comments from disease experts, some item definitions were refined. The interitem correlation in all different categories was lower than 0.7, indicating that there was no redundancy between individual damage items. CONCLUSION: The ADDI is a reliable and valid instrument to quantify damage in individual patients and can be used to compare disease outcomes in clinical studies