Significant improvements in cataract treatment and persistent inequalities in access to cataract surgery among older Poles from 2009 to 2019: results of the PolSenior and PolSenior2 surveys.

Background And Aims: Cataract is the leading cause of visual impairment and blindness among older adults worldwide, that can be corrected through surgical interventions. However, diagnosis and treatment bias can be observed, and it is a major issue for improving health policies. Therefore, we assessed a declared prevalence of cataract and the frequency of surgical treatment of this condition in the Polish population in the years 2009-2019.

Software for the frontiers of quantum chemistry: An overview of developments in the Q-Chem 5 package.

This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange-correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods.

Meniscus of a Magnetic Fluid in the Field of a Current-Carrying Wire: Three-Dimensional Numerical Simulations.

Three-dimensional calculations of the meniscus of a magnetic fluid placed around a current carrying vertical and cylindrical wire are presented. Based on the material properties of experimentally used magnetic fluids, the numerically determined menisci are compared with the experimentally measured ones reported by May. The comparison is made for a linear law of magnetisation as well as for the experimentally measured nonlinear magnetisation curve.

Retarding the growth of the Rosensweig instability unveils a new scaling regime.

Using a highly viscous magnetic fluid, the dynamics in the aftermath of the Rosensweig instability can be slowed down by more than 2000 times. In this way we expand the regime where the growth rate is predicted to scale linearly with the bifurcation parameter by six orders of magnitude, while this regime is tiny for standard ferrofluids and cannot be resolved experimentally there. We measure the growth of the pattern by means of a two-dimensional imaging technique, and find that the slopes of the growth and decay rates are not the same-a qualitative discrepancy with respect to the theoretical predictions.

Multi-state Approach to Chemical Reactivity in Fragment Based Quantum Chemistry Calculations.

We introduce a multistate framework for Fragment Molecular Orbital (FMO) quantum mechanical calculations and implement it in the context of protonated water clusters. The purpose of the framework is to address issues of nonuniqueness and dynamic fragmentation in FMO as well as other related fragment methods. We demonstrate that our new approach, Fragment Molecular Orbital Multistate Reactive Molecular Dynamics (FMO-MS-RMD), can improve energetic accuracy and yield stable molecular dynamics for small protonated water clusters undergoing proton transfer reactions.

Improving Generalized Born Models by Exploiting Connections to Polarizable Continuum Models. II. Corrections for Salt Effects.

A previous analytical investigation of the generalized Born (GB) implicit solvation model is extended to solvents of nonzero ionic strength. The GB model with salt effects (GB-SE) is shown to resemble the Debye-Hückel-like screening model (DESMO), a polarizable continuum model (PCM) that we have recently developed for salty solutions. DESMO may be regarded either as a generalization of the conductor-like PCM (C-PCM) that extends C-PCM to electrolyte solutions or alternatively as a generalization of Debye-Hückel theory to arbitrary cavity shapes.

Improving Generalized Born Models by Exploiting Connections to Polarizable Continuum Models. I. An Improved Effective Coulomb Operator.

We investigate the generalized Born (GB) implicit solvation model in comparison with polarizable continuum models (PCMs). We show that the GB model is intimately connected to the conductor-like PCM (C-PCM), a method that is accurate for high-dielectric solvents but less so for weakly polar and nonpolar solvents. The formal connection between C-PCM and the GB model suggests that C-PCM calculations place a limit on the accuracy that one should expect from GB models but also demonstrates that comparison of GB and C-PCM calculations directly interrogates the accuracy of the effective Coulomb operator that is used in the pairwise GB energy expression.

Patterns of thermomagnetic convection in magnetic fluids subjected to spatially modulated magnetic fields.

An analysis of thermomagnetic convection in a thin horizontal layer of magnetic fluid constrained horizontally by impermeable layers and subjected to a spatially and symmetrically modulated magnetic field is presented. The magnetic field as well as the temperature gradient are oriented vertically. For any nonzero magnetic field the base state is a convective one formed by a double vortex which reflects the symmetrical modulation.

A simple polarizable continuum solvation model for electrolyte solutions.

We propose a Debye-Hückel-like screening model (DESMO) that generalizes the familiar conductor-like screening model (COSMO) to solvents with non-zero ionic strength and furthermore provides a numerical generalization of the Debye-Hückel model that is applicable to non-spherical solute cavities. The numerical implementation of DESMO is based upon the switching/Gaussian (SWIG) method for smooth cavity discretization, which we have recently introduced in the context of polarizable continuum models (PCMs). This approach guarantees that the potential energy is a smooth function of the solute geometry and analytic gradients for DESMO are reported here.

A smooth, nonsingular, and faithful discretization scheme for polarizable continuum models: the switching/Gaussian approach.

Polarizable continuum models (PCMs) are a widely used family of implicit solvent models based on reaction-field theory and boundary-element discretization of the solute/continuum interface. An often overlooked aspect of these theories is that discretization of the interface typically does not afford a continuous potential energy surface for the solute. In addition, we show that discretization can lead to numerical singularities and violations of exact variational conditions.

Both intra- and interstrand charge-transfer excited states in aqueous B-DNA are present at energies comparable to, or just above, the (1)pipi* excitonic bright states.

Vertical electronic excitations in model systems representing single- and double-stranded B-DNA are characterized using electronic structure theory, including both time-dependent density functional theory (TD-DFT) and correlated wave function techniques. Previous TD-DFT predictions of charge-transfer (CT) states well below the optically bright (1)pipi* states are shown to be artifacts of the improper long-range behavior of standard density-functional exchange approximations, which we rectify here using a long-range correction (LRC) procedure. For nucleobase dimers (hydrogen-bonded or pi-stacked), TD-LRC-DFT affords vertical excitation energies in reasonable agreement with the wave function methods, not only for the (1)npi* and (1)pipi* states but also for the CT states, and qualitatively reproduces well-known base-stacking effects on the absorption spectrum of DNA.

Charge-transfer excited states in a pi-stacked adenine dimer, as predicted using long-range-corrected time-dependent density functional theory.

The lowest few electronic excitations of a pi-stacked adenine dimer in its B-DNA geometry are investigated, in the gas phase and in a water cluster, using a long-range-corrected version of time-dependent density functional theory (TD-DFT) that asymptotically incorporates Hartree-Fock exchange. Long-range correction is shown to eliminate the catastrophic underestimation of charge-transfer (CT) excitation energies that plagues conventional TD-DFT, at the expense of introducing one adjustable parameter, mu, that determines the length scale on which Hartree-Fock exchange is turned on. This parameter allows us to interpolate smoothly between hybrid density functionals and time-dependent Hartree-Fock theory.

Growth of surface undulations at the Rosensweig instability.

We investigate the growth of a pattern of liquid crests emerging in a layer of magnetic liquid when subjected to a magnetic field oriented normally to the fluid surface. After a steplike increase of the magnetic field, the temporal evolution of the pattern amplitude is measured by means of a Hall-sensor array. The extracted growth rate is compared with predictions from linear stability analysis by taking into account the proper nonlinear magnetization curve M(H) .

Simple Methods To Reduce Charge-Transfer Contamination in Time-Dependent Density-Functional Calculations of Clusters and Liquids.

Using as benchmarks a series of increasingly large hydrated uracil clusters, we examine the nature and extent of charge-transfer (CT) contamination in condensed-phase, time-dependent density-functional theory. These calculations are plagued by a large number of spurious CT excitations at energies comparable to (and sometimes below) the valence excitation energies, even when hybrid density functionals are used. Spurious states below the first nπ* and ππ* states of uracil are observed in clusters as small as uracil-(H2O)4.

Magnetic Soret effect: application of the ferrofluid dynamics theory.

The ferrofluid dynamics theory is applied to thermodiffusive problems in magnetic fluids in the presence of magnetic fields. The analytical form for the magnetic part of the chemical potential and the most general expression of the mass flux are given. By applying these results to experiments, global Soret coefficients in agreement with measurements are determined.

Oscillatory decay at the Rosensweig instability: experiment and theory.

Transient patterns of the Rosensweig instability are accessed with a pulse sequence. The critical scaling behavior of the oscillation frequency and of the propagation velocity of these patterns is experimentally investigated by switching the magnetic induction to subcritical values. The experimental findings are in good agreement with the linear theory, if the low viscosity and the finite thickness of the magnetic liquid layer are taken into account.

Faraday instability on viscous ferrofluids in a horizontal magnetic field: oblique rolls of arbitrary orientation.

A linear stability analysis of the free surface of a horizontally unbounded ferrofluid layer of arbitrary depth subjected to vertical vibrations and a horizontal magnetic field is performed. A nonmonotonic dependence of the stability threshold on the magnetic field is found at high frequencies of the vibrations. The reasons for the decrease of the critical acceleration amplitude caused by a horizontal magnetic field are discussed.