Electronic structure simulations in the cloud computing environment.

The transformative impact of modern computational paradigms and technologies, such as high-performance computing (HPC), quantum computing, and cloud computing, has opened up profound new opportunities for scientific simulations. Scalable computational chemistry is one beneficiary of this technological progress. The main focus of this paper is on the performance of various quantum chemical formulations, ranging from low-order methods to high-accuracy approaches, implemented in different computational chemistry packages and libraries, such as NWChem, NWChemEx, Scalable Predictive Methods for Excitations and Correlated Phenomena, ExaChem, and Fermi-Löwdin orbital self-interaction correction on Azure Quantum Elements, Microsoft's cloud services platform for scientific discovery.

Symmetry breaking and self-interaction correction in the chromium atom and dimer.

Density functional approximations to the exchange-correlation energy can often identify strongly correlated systems and estimate their energetics through energy-minimizing symmetry-breaking. In particular, the binding energy curve of the strongly correlated chromium dimer is described qualitatively by the local spin density approximation (LSDA) and almost quantitatively by the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA), where the symmetry breaking is antiferromagnetic for both. Here, we show that a full Perdew-Zunger self-interaction-correction (SIC) to LSDA seems to go too far by creating an unphysical symmetry-broken state, with effectively zero magnetic moment but non-zero spin density on each atom, which lies ∼4 eV below the antiferromagnetic solution.

Deletion of the auxiliary α2δ1 voltage sensitive calcium channel subunit in osteocytes and late-stage osteoblasts impairs femur strength and load-induced bone formation in male mice.

Osteocytes sense and respond to mechanical force by controlling the activity of other bone cells. However, the mechanisms by which osteocytes sense mechanical input and transmit biological signals remain unclear. Voltage-sensitive calcium channels (VSCCs) regulate calcium (Ca2+) influx in response to external stimuli.

Orbital dependent complications for close vs well-separated electrons in diradicals.

We investigate two limits in open-shell diradical systems: O3, in which the interesting orbitals are in close proximity to one another, and (C21H13)2, where there is a significant spatial separation between the two orbitals. In accord with earlier calculations, we find that standard density-functional approximations do not predict the open-shell character for the former case but uniformly predict the open-shell character for the latter case. We trace the qualitatively incorrect behavior in O3 predicted by these standard density functional approximations to self-interaction error and use the Fermi-Löwdin-orbital-self-interaction-corrected formalism to determine accurate triplet, closed-shell singlet, and open-shell broken-spin-symmetry electronic configurations.

Use of FLOSIC for understanding anion-solvent interactions.

An Achille's heel of lower-rung density-functional approximations is that the highest-occupied-molecular-orbital energy levels of anions, known to be stable or metastable in nature, are often found to be positive in the worst case or above the lowest-unoccupied-molecular-orbital levels on neighboring complexes that are not expected to accept charge. A trianionic example, [Cr(C2O4)3]3-, is of interest for constraining models linking Cr isotope ratios in rock samples to oxygen levels in Earth's atmosphere over geological timescales. Here we describe how crowd sourcing can be used to carry out self-consistent Fermi-Löwdin-Orbital-Self-Interaction corrected calculations (FLOSIC) on this trianion in solution.

A Novel Simulation Model Significantly Improves Confidence in Canthotomy and Cantholysis Among Ophthalmology and Emergency Medicine Trainees.

Background: Orbital compartment syndrome is a potentially blinding eye condition. Timely diagnosis and treatment are paramount to optimize visual outcomes. Lateral canthotomy and cantholysis is the definitive management and a required competency for emergency physicians and ophthalmologists.

Comparative Density Functional Theory Study of Magnetic Exchange Couplings in Dinuclear Transition-Metal Complexes.

Multicenter transition-metal complexes (MCTMs) with magnetically interacting ions have been proposed as components for information-processing devices and storage units. For any practical application of MCTMs as magnetic units, it is crucial to characterize their magnetic behavior, and in particular, the isotropic magnetic exchange coupling, , between its magnetic centers. Due to the large size of typical MCTMs, density functional theory is the only practical electronic structure method for evaluating the coupling.

Developing a Quantitative Staffing to Workload Tool in an Ambulatory Setting.

Ambulatory staffing to workload based on visit volume in an outpatient setting is an elusive formula, and the literature describing such processes is limited. One health system tasked a multidisciplinary team with developing an ambulatory staffing to workload tool to meet the needs of staff, management, and leadership. The resultant tool includes an automated dashboard for determining staffing needs on the basis of quantified workload, prospective modeling, and historical dashboards to demonstrate actual staffing (full-time equivalents) to workload (outpatient volumes) compared with budget.

Downward quantum learning from element 118: Automated generation of Fermi-Löwdin orbitals for all atoms.

A new algorithm based on a rigorous theorem and quantum data computationally mined from element 118 guarantees automated construction of initial Fermi-Löwdin-Orbital (FLO) starting points for all elements in the Periodic Table. It defines a means for constructing a small library of scalable FLOs for universal use in molecular and solid-state calculations. The method can be systematically improved for greater efficiency and for applications to excited states such as x-ray excitations and optically silent excitations.

Density Matrix Implementation of the Fermi-Löwdin Orbital Self-Interaction Correction Method.

The Fermi-Löwdin orbital self-interaction correction (FLOSIC) method effectively provides a transformation from canonical orbitals to localized Fermi-Löwdin orbitals which are used to remove the self-interaction error in the Perdew-Zunger (PZ) framework. This transformation is solely determined by a set of points in space, called Fermi-Löwdin descriptors (FODs), and the occupied canonical orbitals or the density matrix. In this work, we provide a detailed workflow for the implementation of the FLOSIC method for removal of self-interaction error in DFT calculations in an orbital-by-orbital basis that takes advantage of the unitary invariant nature of the FLOSIC method.

Complex Fermi-Löwdin orbital self-interaction correction.

This paper introduces the use of complex Fermi orbital descriptors (FODs) in the Fermi-Löwdin self-interaction-corrected density functional theory (FLOSIC). With complex FODs, the Fermi-Löwdin orbitals (FLOs) that are used to evaluate the SIC correction to the total energy become complex. Complex FLO-SIC (cFLOSIC) calculations based on the local spin density approximation produce total energies that are generally lower than the corresponding energies found with FLOSIC restricted to real orbitals (rFLOSIC).

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.

Electromagnetic control of spin ordered Mn qubits: a density functional study.

[Mn3O(O2CMe)(dpd3/2)]2 is composed of two monomers each of which contain three Mn atoms at the vertices of an equilateral triangle. A full analysis of the electronic and magnetic structure of the dimer shows that each Mn atom carries a local spin of S = 2 while other spin states are energetically much higher. This result suggests application for conventional as well as quantum tasks.

A multiferroic molecular magnetic qubit.

The chiral FeO(NCH)(OCCH) molecular cation, with C symmetry, is composed of three six-fold coordinated spin-carrying Fe cations that form a perfect equilateral triangle. Experimental reports demonstrating the spin-electric effect in this system also identify the presence of a magnetic uniaxis and suggest that this molecule may be a good candidate for an externally controllable molecular qubit. Here, we demonstrate, using standard density-functional methods, that the spin-electric behavior of this molecule could be even more interesting as there are energetically competitive reference states associated with both high and low local spins (S = 5/2 vs S = 1/2) on the Fe ions.

Collaborative International Research in Clinical and Longitudinal Experience Study in NMOSD.

Objective: To develop a resource of systematically collected, longitudinal clinical data and biospecimens for assisting in the investigation into neuromyelitis optica spectrum disorder (NMOSD) epidemiology, pathogenesis, and treatment.

Methods: To illustrate its research-enabling purpose, epidemiologic patterns and disease phenotypes were assessed among enrolled subjects, including age at disease onset, annualized relapse rate (ARR), and time between the first and second attacks.

Results: As of December 2017, the Collaborative International Research in Clinical and Longitudinal Experience Study (CIRCLES) had enrolled more than 1,000 participants, of whom 77.

Magnetic Signatures of Hydroxyl- and Water-Terminated Neutral and Tetra-Anionic Mn -Acetate.

We investigate the energetics and magnetic signatures of the parent molecular magnet Mn -Acetate [Mn O (COOR) (H O) ] and a chemically decomposed version of this structure, in which the four water molecules are converted to hydroxyl groups and hydrogen molecules. We determine electron addition and water decomposition energetics for this water-containing molecule using density-functional methods and include the recent Fermi-Löwdin-Orbital self-interaction correction. We find that it only costs 0.

Theoretical studies of the vibrational properties of octahedrane (CH): A polyhedral caged hydrocarbon molecule.

The vibrational properties of octahedrane (CH) are calculated using density-functional theory employing two different computational methods: an all-electron Gaussian orbital approach and a Naval Research Laboratory-tight-binding scheme (NRL-TB) coupled with molecular dynamics (NRL-TBMD). Both approaches yield vibrational densities of states for octahedrane that are in good general agreement with each other. NRL Molecular Orbital Library can also provide accurate infrared and Raman spectra which can be analyzed and compared with experimental results, while NRL-TBMD can be conveniently scaled up for larger finite-temperature simulations.

Metastatic testicular Sertoli cell tumor in a free-ranging cryptorchid adult spotted seal Phoca largha in North Slope, Alaska, USA.

This case describes a metastatic Sertoli cell tumor (SCT) with lymphatic spread to the abdominal and thoracic lymph nodes, pancreas, and adrenal gland in an adult spotted seal Phoca largha. The neoplasm was composed of tubules lined by palisading neoplastic cells separated by a variably dense fibrous stroma. This pinniped was 1 of 2 cryptorchid seals and the sole case of genital neoplasia among 70 ice seals necropsied by the North Slope Borough from 2012 to 2017.

Improving the identification and treatment of depression in low-income primary care clinics: a qualitative study of providers in the VitalSign6 program.

Quality Problem: Despite its global burden and prevalence, Major Depressive Disorder often goes undetected and untreated, and is particularly pervasive in the primary care setting.

Initial Assessment: One in four Texans lack health insurance, and people with behavioral health disorders are disproportionately affected. It is possible to provide high-quality depression treatment in primary care settings with outcomes equal to those provided by specialty care.

An approach to value-based simulator selection: The creation and evaluation of the simulator value index tool.

Background: Currently there is no reliable, standardized mechanism to support health care professionals during the evaluation of and procurement processes for simulators. A tool founded on best practices could facilitate simulator purchase processes.

Methods: In a 3-phase process, we identified top factors considered during the simulator purchase process through expert consensus (n = 127), created the Simulator Value Index (SVI) tool, evaluated targeted validity evidence, and evaluated the practical value of this SVI.

Optimising workflow processes in an advanced medication dispensary.

The workload measurement of an inpatient hospital dispensary is critical to improve efficiency in the face of limited budgets. This single-centre pilot study used work sampling to observe and identify areas to improve efficiency of dispensing prescribed medications at one tertiary level acute care teaching hospital. Workload sampling was conducted at a 1096-bed hospital in Calgary, Alberta, Canada.

Symmetry Breaking within Fermi-Löwdin Orbital Self-Interaction Corrected Density Functional Theory.

Fermi-Löwdin orbital self-interaction corrected density functional theory (FLO-SIC DFT) is applied to CH, NO, O, and CH. In general our results indicate that FLO-SIC does favor symmetric setups for molecules with nontrivial chemical bonding. Further we discuss two types of possible symmetry breaking.

Long-Term Effect of the Type of Carotid Endarterectomy on Blood Pressure.

Background: The dissection of the carotid sinus nerve in eversion carotid endarterectomy (eCEA) has been hypothesized to cause an increase in postoperative blood pressure (BP). The objective of this study is to evaluate the effect of eCEA on BP and changes in BP medications over the course of year-long follow-up after eCEA compared with longitudinal incision carotid endarterectomy patch angioplasty (pCEA).

Methods: A retrospective review of patients who underwent CEA between July 1, 2009 and June 30, 2014 in the Vascular Surgery Department at The University of Iowa Hospital and Clinics was conducted.

Self-interaction corrections applied to Mg-porphyrin, C60, and pentacene molecules.

We have applied a recently developed method to incorporate the self-interaction correction through Fermi orbitals to Mg-porphyrin, C60, and pentacene molecules. The Fermi-Löwdin orbitals are localized and unitarily invariant to the Kohn-Sham orbitals from which they are constructed. The self-interaction-corrected energy is obtained variationally leading to an optimum set of Fermi-Löwdin orbitals (orthonormalized Fermi orbitals) that gives the minimum energy.