Self-interaction error overbinds water clusters but cancels in structural energy differences.

We gauge the importance of self-interaction errors in density functional approximations (DFAs) for the case of water clusters. To this end, we used the Fermi-Löwdin orbital self-interaction correction method (FLOSIC) to calculate the binding energy of clusters of up to eight water molecules. Three representative DFAs of the local, generalized gradient, and metageneralized gradient families [i.e., local density approximation (LDA), Perdew-Burke-Ernzerhof (PBE), and strongly constrained and appropriately normed (SCAN)] were used. We find that the overbinding of the water clusters in these approximations is not a density-driven error. We show that, while removing self-interaction error does not alter the energetic ordering of the different water isomers with respect to the uncorrected DFAs, the resulting binding energies are corrected toward accurate reference values from higher-level calculations. In particular, self-interaction-corrected SCAN not only retains the correct energetic ordering for water hexamers but also reduces the mean error in the hexamer binding energies to less than 14 meV/[Formula: see text] from about 42 meV/[Formula: see text] for SCAN. By decomposing the total binding energy into many-body components, we find that large errors in the two-body interaction in SCAN are significantly reduced by self-interaction corrections. Higher-order many-body errors are small in both SCAN and self-interaction-corrected SCAN. These results indicate that orbital-by-orbital removal of self-interaction combined with a proper DFA can lead to improved descriptions of water complexes.

Self-interaction correction in water-ion clusters.

We study the importance of self-interaction errors in density functional approximations for various water-ion clusters. We have employed the Fermi-Löwdin orbital self-interaction correction (FLOSIC) method in conjunction with the local spin-density approximation, Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA), and strongly constrained and appropriately normed (SCAN) meta-GGA to describe binding energies of hydrogen-bonded water-ion clusters, i.e., water-hydronium, water-hydroxide, water-halide, and non-hydrogen-bonded water-alkali clusters. In the hydrogen-bonded water-ion clusters, the building blocks are linked by hydrogen atoms, although the links are much stronger and longer-ranged than the normal hydrogen bonds between water molecules because the monopole on the ion interacts with both permanent and induced dipoles on the water molecules. We find that self-interaction errors overbind the hydrogen-bonded water-ion clusters and that FLOSIC reduces the error and brings the binding energies into closer agreement with higher-level calculations. The non-hydrogen-bonded water-alkali clusters are not significantly affected by self-interaction errors. Self-interaction corrected PBE predicts the lowest mean unsigned error in binding energies (≤50 meV/H2O) for hydrogen-bonded water-ion clusters. Self-interaction errors are also largely dependent on the cluster size, and FLOSIC does not accurately capture the subtle variation in all clusters, indicating the need for further refinement.

Exploring and enhancing the accuracy of interior-scaled Perdew-Zunger self-interaction correction.

The Perdew-Zunger self-interaction correction (PZ-SIC) improves the performance of density functional approximations for the properties that involve significant self-interaction error (SIE), as in stretched bond situations, but overcorrects for equilibrium properties where SIE is insignificant. This overcorrection is often reduced by local scaling self-interaction correction (LSIC) of the PZ-SIC to the local spin density approximation (LSDA). Here, we propose a new scaling factor to use in an LSIC-like approach that satisfies an additional important constraint: the correct coefficient of the atomic number Z in the asymptotic expansion of the exchange-correlation (xc) energy for atoms. LSIC and LSIC+ are scaled by functions of the iso-orbital indicator zσ, which distinguishes one-electron regions from many-electron regions. LSIC+ applied to the LSDA works better for many equilibrium properties than LSDA-LSIC and the Perdew, Burke, and Ernzerhof generalized gradient approximation (GGA), and almost close to the strongly constrained and appropriately normed (SCAN) meta-GGA. LSDA-LSIC and LSDA-LSIC+, however, fail to predict interaction energies involving weaker bonds, in sharp contrast to their earlier successes. It is found that more than one set of localized SIC orbitals can yield a nearly degenerate energetic description of the same multiple covalent bond, suggesting that a consistent chemical interpretation of the localized orbitals requires a new way to choose their Fermi orbital descriptors. To make a locally scaled down SIC to functionals beyond the LSDA requires a gauge transformation of the functional's energy density. The resulting SCAN-sdSIC, evaluated on SCAN-SIC total and localized orbital densities, leads to an acceptable description of many equilibrium properties including the dissociation energies of weak bonds.

Understanding social workers' hidden roles in medication safety for older adults: A qualitative study.

Older adults are vulnerable to risks associated with medications. This study explores the roles of Social Workers in facilitating medication safety for older adults. Eight social workers from federally qualified health centers participated in a case-based and interactive medication safety curriculum. They participated in an in-depth, semi-structured interview to explore their roles and strategies in assisting older adults and caregivers with medication management. Findings were transcribed and analyzed. Six themes characterizing social workers' roles in medication management were identified: a) Referral: matching patients and medication-related resources within the health-care system and community; b) Communication: connecting providers, patients, caregivers, and support system; c) Access to medicine: addressing unique needs of each patient to foster their ability to obtain their medicines; d) Social Determinants of Health: investigating the social challenges of each patient and facilitating specific medication management approaches to meet identified needs; e) Engagement: engaging patients in co-developing a treatment plan; f) Caregiver Support: preparing caregivers to assist in medication management. Social workers are trained and well positioned to provide a multi-faceted approach to improve medication management for older adults. Their unique perspectives and skills are important in addressing the complex challenges of medication management.

Simple hydrogenic estimates for the exchange and correlation energies of atoms and atomic ions, with implications for density functional theory.

Exact density functionals for the exchange and correlation energies are approximated in practical calculations for the ground-state electronic structure of a many-electron system. An important exact constraint for the construction of approximations is to recover the correct non-relativistic large-Z expansions for the corresponding energies of neutral atoms with atomic number Z and electron number N = Z, which are correct to the leading order (-0.221Z5/3 and -0.021Z ln Z, respectively) even in the lowest-rung or local density approximation. We find that hydrogenic densities lead to Ex(N, Z) ≈ -0.354N2/3Z (as known before only for Z ≫ N ≫ 1) and Ec ≈ -0.02N ln N. These asymptotic estimates are most correct for atomic ions with large N and Z ≫ N, but we find that they are qualitatively and semi-quantitatively correct even for small N and N ≈ Z. The large-N asymptotic behavior of the energy is pre-figured in small-N atoms and atomic ions, supporting the argument that widely predictive approximate density functionals should be designed to recover the correct asymptotics. It is shown that the exact Kohn-Sham correlation energy, when calculated from the pure ground-state wavefunction, should have no contribution proportional to Z in the Z → ∞ limit for any fixed N.

A step in the direction of resolving the paradox of Perdew-Zunger self-interaction correction. II. Gauge consistency of the energy density at three levels of approximation.

The Perdew-Zunger (PZ) self-interaction correction (SIC) was designed to correct the one-electron limit of any approximate density functional for the exchange-correlation (xc) energy, while yielding no correction to the exact functional. Unfortunately, it spoils the slowly varying (in space) limits of the uncorrected approximate functionals, where those functionals are right by construction. The right limits can be restored by locally scaling down the energy density of the PZ SIC in many-electron regions, but then a spurious correction to the exact functional would be found unless the self-Hartree and exact self-xc terms of the PZ SIC energy density were expressed in the same gauge. Only the local density approximation satisfies the same-gauge condition for the energy density, which explains why the recent local-scaling SIC is found here to work excellently for atoms and molecules only with this basic approximation and not with the more advanced generalized gradient approximations (GGAs) and meta-GGAs, which lose the Hartree gauge via simplifying integrations by parts. The transformation of energy density that achieves the Hartree gauge for the exact xc functional can also be applied to approximate functionals. Doing so leads to a simple scaled-down self-interaction correction that is typically much more accurate than PZ SIC in tests for many molecular properties (including equilibrium bond lengths). The present work unambiguously shows that the largest errors of PZ SIC applied to standard functionals at three levels of approximation can be removed by restoring their correct slowly varying density limits. It also confirms the relevance of these limits to atoms and molecules.

Stretched or noded orbital densities and self-interaction correction in density functional theory.

Semilocal approximations to the density functional for the exchange-correlation energy of a many-electron system necessarily fail for lobed one-electron densities, including not only the familiar stretched densities but also the less familiar but closely related noded ones. The Perdew-Zunger (PZ) self-interaction correction (SIC) to a semilocal approximation makes that approximation exact for all one-electron ground- or excited-state densities and accurate for stretched bonds. When the minimization of the PZ total energy is made over real localized orbitals, the orbital densities can be noded, leading to energy errors in many-electron systems. Minimization over complex localized orbitals yields nodeless orbital densities, which reduce but typically do not eliminate the SIC errors of atomization energies. Other errors of PZ SIC remain, attributable to the loss of the exact constraints and appropriate norms that the semilocal approximations satisfy, suggesting the need for a generalized SIC. These conclusions are supported by calculations for one-electron densities and for many-electron molecules. While PZ SIC raises and improves the energy barriers of standard generalized gradient approximations (GGAs) and meta-GGAs, it reduces and often worsens the atomization energies of molecules. Thus, PZ SIC raises the energy more as the nodality of the valence localized orbitals increases from atoms to molecules to transition states. PZ SIC is applied here, in particular, to the strongly constrained and appropriately normed (SCAN) meta-GGA, for which the correlation part is already self-interaction-free. This property makes SCAN a natural first candidate for a generalized SIC.

Effect of Dynamical Motion in ab Initio Calculations of Solid-State Nuclear Magnetic and Nuclear Quadrupole Resonance Spectra.

Solid-state nuclear magnetic resonance (SSNMR) and nuclear quadrupole resonance (NQR) spectra provide detailed information about the electronic and atomic structure of solids. Modern ab initio methods such as density functional theory (DFT) can be used to calculate NMR and NQR spectra from first-principles, providing a meaningful avenue to connect theory and experiment. Prediction of SSNMR and NQR spectra from DFT relies on accurate calculation of the electric field gradient (EFG) tensor associated with the potential of electrons at the nuclear centers. While static calculations of EFGs are commonly seen in the literature, the effects of dynamical motion of atoms in molecules and solids have been less explored. In this study, we develop a method to calculate EFGs of solids while taking into account the dynamics of atoms through DFT-based molecular dynamics simulations. The method we develop is general, in the sense that it can be applied to any material at any desired temperature and pressure. Here, we focus on application of the method to NaNO2 and study in detail the EFGs of 14N, 17O, and 23Na. We find in the cases of 14N and 17O that the dynamical motion of the atoms can be used to calculate mean EFGs that are in closer agreement with experiments than those of static calculations. For 23Na, we find a complex behavior of the EFGs when atomic motion is incorporated that is not at all captured in static calculations. In particular, we find a distribution of EFGs that is influenced strongly by the local (changing) bond environment, with a pattern that reflects the coordination structure of 23Na. We expect the methodology developed here to provide a path forward for understanding materials in which static EFG calculations do not align with experiments.

COVID-19 disease trajectories among nursing home residents.

INTRODUCTION: Older adults are at greater risk of both infection with and mortality from COVID-19. Many U.S. nursing homes have been devastated by the COVID-19 pandemic, yet little has been described regarding the typical disease course in this population. The objective of this study is to describe and identify patterns in the disease course of nursing home residents infected with COVID-19. SETTING AND METHODS: This is a case series of 74 residents with COVID-19 infection in a nursing home in central Indiana between March 28 and June 17, 2020. Data were extracted from the electronic medical record and from nursing home medical director tracking notes from the time of the index infection through August 31, 2020. The clinical authorship team reviewed the data to identify patterns in the disease course of the residents. RESULTS: The most common symptoms were fever, hypoxia, anorexia, and fatigue/malaise. The duration of symptoms was extended, with an average of over 3 weeks. Of those infected 25 died; 23 of the deaths were considered related to COVID-19 infection. A subset of residents with COVID-19 infection experienced a rapidly progressive, fatal course. DISCUSSION/CONCLUSIONS: Nursing home residents infected with COVID-19 from the facility we studied experienced a prolonged disease course regardless of the severity of their symptoms, with implications for the resources needed to care for and support of these residents during active infection and post-disease. Future studies should combine data from nursing home residents across the country to identify the risk factors for disease trajectories identified in this case series.

Caregiver-Based Interventions to Optimize Medication Safety in Vulnerable Elderly Adults: A Systematic Evidence-Based Review.

OBJECTIVES: To study the effect of caregiver-focused interventions to support medication safety in older adults with chronic disease. DESIGN: Systematic review. SETTING: Studies published before January 31, 2017, searched using Ovid Medline, PubMed, EMBASE, Scopus, CINAHL, PsycINFO, and Google Scholar. PARTICIPANTS: Caregivers with or without a care recipient. MEASUREMENTS: Inclusion criteria: interventions focused on caregivers aiming to improve medication safety. Studies not focusing on older adults, not evaluating medication safety, failing to include caregivers, or without a comparison group were excluded. RESULTS: The initial search revealed 1,311 titles. Eight studies met inclusion criteria. The strategies used in randomized trials were a home-based medication review and adherence assessment by a clinical pharmacist (2 home visits 6-8 weeks apart, with pharmacist and physician meeting independently) that found no difference in nonelective hospital admissions (p=.8) but fewer medications (p=.03); a 19-minute educational DVD and an hour-long medication education and training that improved caregiver satisfaction (p<.04); a medication education and adherence intervention (2-3 home visits per care recipient and caregiver dyad over 8 weeks) that found no difference in knowledge, administration, or accessibility of medications (p=.29); and a collaborative case management program (16-month program of assessment, meeting, and monthly follow-up telephone calls) that reduced perceived caregiver burden (p=.03). Quasi-experimental trials included collaborative care transitional coaches, an outpatient collaborative care model, and education and training programs. Of these, educational interventions showed improvements in self-efficacy, confidence, and preparedness. The collaborative care intervention reduced rehospitalizations (p=.04) and improved quality-of-care outcomes. CONCLUSION: Although some interventions improved caregiver medication knowledge and self-efficacy, effects on clinical outcomes and healthcare use were insufficiently studied. Two studies implementing collaborative care models with medication management components showed potential for improvement in quality of clinical care and reductions in healthcare visits and warrant further study with respect to medication safety. J Am Geriatr Soc 66:2128-2135, 2018.

Incidence of cholinesterase inhibitor therapy initiation among hospitalized patients.

BACKGROUND: Initiation of cholinesterase inhibitor (ChEI) therapy for delirium during hospitalization is ineffective and may be associated with increased morbidity and mortality. OBJECTIVE: To describe the incidence of initiating ChEI therapy during hospitalization. DESIGN: A retrospective cross-sectional study. SETTING: A tertiary-care academic medical center. PATIENTS: Inpatient admissions from September 2010 through March 2011 with ChEI administration. INTERVENTION: None. MEASUREMENTS: Incidence of ChEI exposure, initiation of ChEI therapy, initiation of antipsychotics and benzodiazepines, infection, in-hospital mortality, and hospital length of stay. RESULTS: The incidence of adult admissions with ChEI exposure and ChEI initiation was 23.2 (95% confidence interval: 21.2-25.4) and 2 (95% confidence interval 1.5-2.8) per 1000 admissions, respectively. Of 476 admissions receiving ChEI, 9% (n = 42) initiated therapy during the hospital stay and 91% (n = 434) continued on previously started therapy. Patients initiated on ChEI therapy frequently had infection (20 of 42) and were commonly initiated on antipsychotics (14 of 42) and benzodiazepines (13 of 42). Patients were hospitalized for a median of 2 days (interquartile range, 1-4) before initiation of ChEI and were exposed to therapy for a median of 3 days (interquartile range, 2-6). Of the 41 patients discharged from the hospital, 90% (n = 37) had orders to continue the ChEI postdischarge. CONCLUSIONS: Despite a lack of evidence to support the practice, 9% of patients who received ChEI therapy were initiated during the inpatient setting. These patients were not routinely screened for delirium and frequently received treatments associated with delirium.

Initiation of cholinesterase inhibitors in an inpatient setting.

We examined initiation of cholinesterase inhibitors (ChEIs) to determine whether ChEIs were being newly prescribed without sufficient evaluation for dementia and/or delirium and to explore whether there are differences in outcomes, such as mortality, hospital readmission rates, and duration of hospitalization, between patients newly started on ChEI and those who continued such medications prior to admission. Patients hospitalized in fiscal year 2008 and prescribed ChEI were identified. We reviewed electronic medical records. Of 282 patients, 15.6% (44) were new-starts and 84.4% (238) were continuations. Median length of stay was 16 days in new-starts versus 6 days in continuations (P < .05). Of new-starts, 38.6% were also treated of infection. Chart review additionally suggested possible treatment of delirium by initiation of benzodiazepines and antipsychotics in 11.4% and 22.7% of new-starts, respectively. We observed a substantive practice of initiating ChEIs in hospitalized elderly patients at risk of delirium. Although there was no difference in the 30-day mortality or readmission rates, new-starts were more likely to have a longer hospital stay than continuation patients.

The implications of increasing age on erectile dysfunction.

Erectile dysfunction (ED) has long been correlated with psychological well-being. More recently, an understanding has developed of ED being, in some cases, a vascular condition of the penile artery. Given the narrowness of the penile artery, a small amount of atherosclerosis may result in ED before any other manifestations are evident, making ED a useful marker for other vascular conditions with potentially greater clinical implications. In light of this, possible underreporting of ED takes on added significance. A questionnaire regarding ED prevalence and management was distributed for self-administration to men in the waiting room of primary care clinics; the data were analyzed with a focus on the relationship between ED and age. The study had a remarkable response rate of >95%. The prevalence of ED in the ≥70-year age-group was 77%, compared with 61% in the 40- to 69-year age-group (p = .0001). ED correlated linearly with age (R(2) = .80, p < .0001). Among those who had ED, more than half had not discussed it with any provider; the likelihood of discussing ED did increase with the reported severity of symptoms (p < .0001). Older men had more severe ED than younger men (p < .0001). Furthermore, 72% of men with a history of ED were never treated. Younger men were more likely to be treated than older men (p = .004). Given the potential implications of underreporting ED, and the willingness of the men in this study to complete the questionnaire, further work may be merited on new models for ED assessment and follow-up.