The calculation of the analytical second derivative matrix (Hessian) is the bottleneck for vibrational analysis in QM/MM systems when an electrostatic embedding scheme is employed. Even with a small number of QM atoms in the system, the presence of MM atoms increases the computational cost dramatically: the long-range Coulomb interactions require that additional coupled perturbed self-consisten...

Version 9 of the Amber simulation programs includes a new semi-empirical hybrid QM/MM functionality. This includes support for implicit solvent (generalized Born) and for periodic explicit solvent simulations using a newly developed QM/MM implementation of the particle mesh Ewald (PME) method. The code provides sufficiently accurate gradients to run constant energy QM/MM MD simulations for many...

An abelian surface A is called a QM-abelian surface if its endomorphism ring includes an order of an indefinite quaternion algebra, and a curve C of genus two is called a QM-curve if its jacobian variety is a QMabelian surface. We give a computational result about the distribution of the arguments of the eigenvalues of the Frobenius endomorphisms of QM-abelian surfaces modulo good primes, which...

OBJECTIVES The primary objective was to describe the current level of implementation of quality management (QM) structures and practices with Australian emergency departments. The secondary objective was to describe the level of association between the presence of QM structures and processes and the achievement of associated improvements. DESIGN Data were collected by mail-out of a structured...

We present results of fully 2D quantum-mechanical (QM) simulations of nanoscale MOSFET's. The validity of semiclassical transport models are first discussed. Then, QM effects on threshold voltage, subthreshold slope and short-channel performances are addressed. We show that QM effects significantly affect device performances in the nanoscale range.

We have carried out quantum mechanical (QM) and QM/MM (combined QM and molecular mechanics) calculations, as well as molecular dynamics (MD) simulations to study the binding of a series of six RAPTA (Ru(II)-arene-1,3,5-triaza-7-phosphatricyclo-[3.3.1.1] decane) complexes with different arene substituents to cathepsin B. The recently developed QM/MM-PBSA approach (QM/MM combined with Poisson-Bol...

The overwhelming majority of scientists still takes it for granted that classical mechanics (ClM) is nothing but a limiting case of quantum mechanics (QM). Although some physicists restrict this belief to a generalized QM as represented, e. g., by the algebra of observables, it will be shown in this contribution that the view of ClM as a mere sub-set of QM is nevertheless unfounded. The usual a...

A robust approach for dealing with electrostatic interactions for spherical boundary conditions has been implemented in the QM/MM framework. The development was based on the generalized solvent boundary potential (GSBP) method proposed by Im et al. [J. Chem. Phys. 114, 2924 (2001)], and the specific implementation was applied to the self-consistent-charge density-functional tight-binding approa...

Quality computational description of metalloproteins is a great challenge due to the vast span of time- and lengthscales characteristic of their existence. We present an efficient new method that allows for robust characterization of metalloproteins. It combines quantum mechanical (QM) description of the metal-containing active site, and extensive dynamics of the protein captured by discrete mo...

This paper studies numerical integration (or cubature) over the unit sphere S2 ⊂ R3 for functions in arbitrary Sobolev spaces Hs(S2), s > 1. We discuss sequences (Qm(n))n∈N of cubature rules, where (i) the rule Qm(n) uses m(n) points and is assumed to integrate exactly all (spherical) polynomials of degree ≤ n, and (ii) the sequence (Qm(n)) satisfies a certain local regularity property. This lo...