An idealized four-site ionic liquid model having characteristics approximating those of 1-butyl-3-methylimidazolium hexafluorophosphate ([Im(41)][PF(6)]) is introduced as a low-cost alternative to existing all-atom models for purposes of simulating solute-based dynamics over nanosecond and longer time scales. The structural and energetic properties of the model are in reasonable agreement with those of [Im(41)][PF(6)] and similar ionic liquids, but the dynamics are unrealistically slow. A temperature shift of approximately 100 K is required to produce agreement between the viscosity and diffusion coefficients of the model and experimental values. Several aspects of the ion dynamics such as subdiffusive translational motions, non-Gaussian van Hove distributions, and jumplike displacements in both positions and orientations, are similar to behavior observed in supercooled liquids. Translational diffusion coefficients and rotational correlation times show roughly the proportionalities to viscosity expected from hydrodynamic models, and slip hydrodynamic calculations provide reasonable accuracy in some cases. But anomalously high rotational diffusion coefficients which decouple from viscosity at low temperature are also observed. These anomalies are explained in terms of the prevalence of 180 degrees rotational jumps coupled to the presence of marked heterogeneity in rotational motions, especially about one molecular axis. Comparisons between the dynamics observed in the ionic liquid (IL) model and a neutral mixture (NM) counterpart help to explain the origins of the distinctive dynamics in ionic liquids compared to conventional solvents. The requirement for balancing electrostatic interactions in the IL leads to uniform and interleaved distributions of cations and anions resembling a distorted ionic lattice, similar to the structure of molten NaCl. The resistance to reorganizing this structure is what leads to the slow dynamics of ionic liquids. The coupling among large collections of ions is presumably responsible for the similarity of ionic liquids to supercooled conventional liquids.

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The results suggest that plasma level of D-dimer can give an additional contribution for the evaluation of the severity of CAP and its complications in children.

Paravalvular leak can complicate transcatheter aortic valve replacement with important prognostic implications. Correction of defects requires complex planning and execution. Multiple or irregular lesions, calcified annulus, and high sealing skirts on self-expandable devices are especially challenging. Such defects may be approximated using malleable vascular closure devices. ( Level of Difficulty: Intermediate. )

A best evidence topic was written according to a structured protocol. The question addressed was ‘Do patients with centrifugal flow HeartMate 3 (HM3) or HeartWare left ventricular assist device (HVAD) have better outcomes compared to those with the axial flow HeartMate II (HMII)?’ Altogether 1791 papers were found using the reported search, of which 21 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. In publications reporting on MOMENTUM 3 randomized control trial (RCT), HM3 had better outcomes compared to HMII with a lower rate of pump thrombosis (1.1% vs 15.7%), stroke events (10.1% vs 19.2%) and ischaemic stroke (6.3% vs 13.4%) at 2-year follow-up. Markers of quality of life and functional capacity were comparable between the 2 devices at 6 months. In publications reporting on ENDURANCE RCTs, compared to HMII, patients with HVAD had poorer outcomes with an increased rate of sepsis (23.6% vs 15.4%), stroke (29.7% vs 12.1%) and right heart failure (38.5% vs 26.8%) postoperatively. Outcomes were improved for the HVAD group in a more recent RCT where strict blood pressure control was instigated postoperatively. Outcomes from retrospective studies comparing HMII with HVAD varied, with some publications reporting higher rates of right ventricular assist device use (29% vs 15%), gastrointestinal bleeding (30% vs 0%), cerebrovascular accident (44% vs 10%), transient ischaemic attack (5% vs 2%) and higher cumulative risk of infection and haemorrhagic cerebrovascular accident with HVAD. This is not consistent across these studies, and 9 studies including a systematic review reported no difference in any outcomes. In conclusion, patients with centrifugal flow HM3 have better outcomes than those with axial flow HMII. Although there is some variability in outcomes in retrospective studies, patients with centrifugal flow HeartWare HVAD have similar outcomes to those with axial flow HMII when strict blood pressure control is instigated postoperatively. By inference, centrifugal flow HM3 would appear to be the superior device, although all conclusions are based on 1 large (industry-sponsored) RCT.