Device Exchange to HeartMate 3 LVAD: Impact of Previous Pump Model on Clinical Outcomes.

Background: We describe our clinical experience performing device exchange from a HeartMate II (HM2) or HVAD to a HeartMate 3 (HM3) left ventricular assist device.

Methods: A single-center retrospective study was performed of all patients (N = 14) who underwent a left ventricular assist device exchange from HM2 (n = 7) or HVAD (n = 7) to HM3 between October 2018 and October 2021. The primary outcome was 1-year overall survival, and secondary outcomes included adverse events through discharge.

Coarse-grained protein-protein stiffnesses and dynamics from all-atom simulations.

Large protein assemblies, such as virus capsids, may be coarse-grained as a set of rigid units linked by generalized (rotational and stretching) harmonic springs. We present an ab initio method to obtain the elastic parameters and overdamped dynamics for these springs from all-atom molecular-dynamics simulations of one pair of units at a time. The computed relaxation times of this pair give a consistency check for the simulation, and we can also find the corrective force needed to null systematic drifts.

Irreversible growth model for virus capsid assembly.

We model the spontaneous assembly of a capsid (a virus' closed outer shell) from many copies of identical units, using entirely irreversible steps and only information local to the growing edge. Our model is formulated in terms of (i) an elastic Hamiltonian with stretching and bending stiffness and a spontaneous curvature, and (ii) a set of rate constants for the addition of new units or bonds. An ensemble of highly irregular capsids is generated, unlike the well-known icosahedrally symmetric viruses, but (we argue) plausible as a way to model the irregular capsids of retroviruses such as HIV.