TREXIO: A file format and library for quantum chemistry.

TREXIO is an open-source file format and library developed for the storage and manipulation of data produced by quantum chemistry calculations. It is designed with the goal of providing a reliable and efficient method of storing and exchanging wave function parameters and matrix elements, making it an important tool for researchers in the field of quantum chemistry. In this work, we present an overview of the TREXIO file format and library. The library consists of a front-end implemented in the C programming language and two different back-ends: a text back-end and a binary back-end utilizing the hierarchical data format version 5 library, which enables fast read and write operations. It is compatible with a variety of platforms and has interfaces for Fortran, Python, and OCaml programming languages. In addition, a suite of tools have been developed to facilitate the use of the TREXIO format and library, including converters for popular quantum chemistry codes and utilities for validating and manipulating data stored in TREXIO files. The simplicity, versatility, and ease of use of TREXIO make it a valuable resource for researchers working with quantum chemistry data.

Fractional occupation numbers and self-interaction correction-scaling methods with the Fermi-Löwdin orbital self-interaction correction approach.

We present a new assessment of the Fermi-Löwdin orbital self-interaction correction (FLO-SIC) approach with an emphasis on its performance for predicting energies as a function of fractional occupation numbers (FONs) for various multielectron systems. Our approach is implemented in the massively parallelized NWChem quantum chemistry software package and has been benchmarked on the prediction of total energies, atomization energies, and ionization potentials of small molecules and relatively large aromatic systems. Within our study, we also derive an alternate expression for the FLO-SIC energy gradient expressed in terms of gradients of the Fermi-orbital eigenvalues and revisit how the FLO-SIC methodology can be seen as a constrained unitary transformation of the canonical Kohn-Sham orbitals. Finally, we conclude with calculations of energies as a function of FONs using various SIC-scaling methods to test the limits of the FLO-SIC formalism on a variety of multielectron systems. We find that these relatively simple scaling methods do improve the prediction of total energies of atomic systems as well as enhance the accuracy of energies as a function of FONs for other multielectron chemical species.

Real-time degradation dynamics of hydrated per- and polyfluoroalkyl substances (PFASs) in the presence of excess electrons.

Per- and polyfluoroalkyl substances (PFASs) are synthetic chemicals that are harmful to both the environment and human health. Using self-interaction-corrected Born-Oppenheimer molecular dynamics simulations, we provide the first real-time assessment of PFAS degradation in the presence of excess electrons. In particular, we show that the initial phase of the degradation involves the transformation of an alkane-type C-C bond into an alkene-type C[double bond, length as m-dash]C bond in the PFAS molecule, which is initiated by the trans elimination of fluorine atoms bonded to these adjacent carbon atoms.

Large-scale first principles configuration interaction calculations of optical absorption in aluminum clusters.

We report the linear optical absorption spectra of aluminum clusters Aln (n = 2-5) involving valence transitions, computed using the large-scale all-electron configuration interaction (CI) methodology. Several low-lying isomers of each cluster were considered, and their geometries were optimized at the coupled-cluster singles-doubles (CCSD) level of theory. With these optimized ground-state geometries, excited states of different clusters were computed using the multi-reference singles-doubles configuration-interaction (MRSDCI) approach, which includes electron correlation effects at a sophisticated level. These CI wave functions were used to compute the transition dipole matrix elements connecting the ground and various excited states of different clusters, and thus their photoabsorption spectra. The convergence of our results with respect to the basis sets, and the size of the CI expansion, was carefully examined. Our results were found to be significantly different as compared to those obtained using time-dependent density functional theory (TDDFT) [Deshpande et al. Phys. Rev. B: Condens. Matter Mater. Phys., 2003, 68, 035428]. When compared to the available experimental data for the isomers of Al2 and Al3, our results are in very good agreement as far as important peak positions are concerned. The contribution of configurations to many body wave functions of various excited states suggests that in most cases optical excitations involved are collective, and plasmonic in nature.

Effect of Integrated Survivorship Model on Physical Health for Breast Cancer Survivors in Rural Area.

OBJECTIVE: The objective of this study was to evaluate the effect of the integrated survivorship model on the physical health of breast cancer survivors in rural areas. METHODS:  Ninety-two patients who were breast cancer survivors were selected as per inclusion criteria and divided into two groups (control group and intervention group). The participants were randomly allotted to two groups of 46 each. A 12-minute walk test, assessment of quality of life, and difficulty in return to work were used as outcome measures. The integrated survivorship model was implemented in one group for 3 months while the other group was a supporting group and was involved in household activities only. Pre-assessment and post-assessment were taken to evaluate the effect of the integrated survivorship model. All the statistical analysis was done using SPSS statistical Software (version 23.0 for Windows; SPSS, Inc., Chicago, USA) and the results were obtained. RESULTS: The results revealed that the assessment of the 12-minute walk test, physical well-being, social/family well-being, functional well-being, and difficulty in returning to work showed extremely significant results in the intervention group with a p-value of less than 0.0001. Similarly, emotional well-being and additional concern domains showed significant results in the intervention group. Hence, the findings of this study revealed significance in post-assessment in all the outcome measures of the experimental group. CONCLUSION: The study showed that all the outcome measures such as the 12-minute walk test, assessment of quality of life, and difficulty in return to work were impaired in both groups before the study. The effect of the model showed a significant improvement in the intervention group after implementing the intervention.

Photo-induced degradation of PFASs: Excited-state mechanisms from real-time time-dependent density functional theory.

Per- and polyfluoroalkyl substances (PFASs) are hazardous, carcinogenic, and bioaccumulative contaminants found in drinking water sources. To mitigate and remove these persistent pollutants, recent experimental efforts have focused on photo-induced processes to accelerate their degradation; however, the mechanistic details of these promising degradation processes remain unclear. To shed crucial insight on these electronic-excited state processes, we present the first study of photo-induced degradation of explicitly-solvated PFASs using excited-state, real-time time-dependent density functional theory (RT-TDDFT) calculations. Furthermore, our large-scale RT-TDDFT calculations show that these photo-induced excitations can be highly selective by enabling a charge-transfer process that only dissociates the CF bond while keeping the surrounding water molecules intact. Collectively, the RT-TDDFT techniques used in this work (1) enable a new capability for probing photo-induced mechanisms that cannot be gleaned from conventional ground-state DFT calculations and (2) provide a rationale for understanding ongoing experiments that are actively exploring photo-induced degradation of PFASs and other environmental contaminants.

Evaluation of the Safety and Efficacy of Favipiravir in Adult Indian Patients with Mild-to-Moderate COVID-19 in a Real-World Setting.

Purpose: To evaluate the safety and efficacy of favipiravir, which is prescribed for the treatment of patients with mild-to-moderate coronavirus disease 2019 (COVID-19) in India. Patients and Methods: This was a prospective, open-label, multicenter, single-arm postmarketing study conducted in India. Patients with mild-to-moderate COVID-19 received favipiravir (3600 mg [1800 mg orally twice daily] on the first day, followed by 800 mg orally twice daily, up to a maximum of 14 days) as a part of their treatment. The primary endpoints were to evaluate the safety of favipiravir by assessing the number of adverse events (AEs) and treatment-related AEs. The secondary endpoints were to evaluate the efficacy of favipiravir by assessing time to clinical cure, rate of clinical cure, time to pyrexia resolution, rate of oxygen requirement, and all-cause mortality. Results: A total of 1083 patients were enrolled in this study from December 2020 to June 2021. Adverse events were reported in 129 patients (11.9%), 116 (10.7%) of whom had mild AEs. Dose modification or withdrawal of favipiravir treatment was reported in four patients (0.37%). The median time to clinical cure and pyrexia resolution was 7 and 4 days, respectively. A total of 1036 patients (95.8%) exhibited clinical cure by day 14. Oxygen support was required by 15 patients (1.4%). One death was reported, which was unrelated to favipiravir. Conclusion: In the real-world setting, favipiravir was well-tolerated, and no new safety signals were detected.

Anisotropic Interlayer Exciton in GeSe/SnS van der Waals Heterostructure.

Stacking two or more two-dimensional materials to form a heterostructure is becoming the most effective way to generate new functionalities for specific applications. Herein, using GW and Bethe-Salpeter equation simulations, we demonstrate the generation of linearly polarized, anisotropic intra- and interlayer excitonic bound states in the transition metal monochalcogenide (TMC) GeSe/SnS van der Waals heterostructure. The puckered structure of TMC results in the directional anisotropy in band structure and in the excitonic bound state. Upon the application of compressive/tensile biaxial strain dramatic variation (∓3%) in excitonic energies, the indirect-to-direct semiconductor transition and the red/blue shift of the optical absorption spectrum are observed. The variations in excitonic energies and optical band gap have been attributed to the change in effective dielectric constant and band dispersion upon the application of biaxial strain. The generation and control over the interlayer excitonic energies can find applications in optoelectronics and optical quantum computers and as a gain medium in lasers.

Improved band gaps and structural properties from Wannier-Fermi-Löwdin self-interaction corrections for periodic systems.

The accurate prediction of band gaps and structural properties in periodic systems continues to be one of the central goals of electronic structure theory. However, band gaps obtained from popular exchange-correlation (XC) functionals (such as LDA and PBE) are severely underestimated partly due to the spurious self-interaction error (SIE) inherent to these functionals. In this work, we present a new formulation and implementation of Wannier function-derived Fermi-Löwdin (WFL) orbitals for correcting the SIE in periodic systems. Since our approach utilizes a variational minimization of the self-interaction energy with respect to the Wannier charge centers (WCC), it is computationally more efficient than the HSE hybrid functional and other self-interaction corrections that require a large number of transformation matrix elements. Calculations on several (17 in total) prototypical molecular solids, semiconductors, and wide-bandgap materials show that our WFL self-interaction correction approach gives better band gaps and bulk moduli compared to semilocal functionals, largely due to the partial removal of self-interaction errors.

Pressure-Induced Topological Phase Transitions in CdGeSb2 and CdSnSb2.

Using first-principles calculations, we study the occurrence of topological quantum phase transitions (TQPTs) as a function of hydrostatic pressure in CdGeSb2 and CdSnSb2 chalcopyrites. At ambient pressure, both materials are topological insulators, having a finite band gap with inverted order of Sb-s and Sb-p x,p y orbitals of valence bands at the Γ point. Under hydrostatic pressure, the band gap reduces, and at the critical point of the phase transition, these materials turn into Dirac semimetals. Upon further increasing the pressure beyond the critical point, the band inversion is reverted, making them trivial insulators. This transition is also captured by the Lüttinger model Hamiltonian, which demonstrates the critical role played by pressure-induced anisotropy in frontier bands in driving the phase transitions. These theoretical findings of peculiar coexistence of multiple topological phases provide a realistic and promising platform for experimental realization of the TQPTs.

Multiple triple-point fermions in Heusler compounds.

Using the density functional theoretical calculations, we report a new set of topological semimetals X2YZ (X = {Cu, Rh, Pd, Ag, Au, Hg}, Y = {Li, Na, Sc, Zn, Y, Zr, Hf, La, Pr, Pm, Sm, Tb, Dy, Ho, Tm} and Z = {Mg, Al, Zn, Ga, Y, Ag, Cd, In, Sn, Ta, Sm}), which show the existence of multiple topological triple point fermions along four independent [Formula: see text] axes. These fermionic quasiparticles have no analogues elementary particle in the standard model. The angle-resolved photoemission spectroscopy is simulated to obtain the exotic topological surface states and the characteristic Fermi arcs. The inclusion of spin-orbit coupling splits the triple-point to two Dirac points. The triple-point fermions are exhibited on the easily cleavable (1 1 1) surface and are well separated from the surface [Formula: see text] point, allowing them to be resolved in the surface spectroscopic techniques. This intermediate linearly dispersive degeneracy between Weyl and Dirac points may offer prospective candidates for quantum transport applications.

Benchmarking Quantum Chemical Methods for Optical Absorption in Boron Wheels.

We benchmark various quantum chemical methods for calculating the optical absorption in planar boron wheel clusters. The geometries of neutral planar boron wheels B7, B8, and B9 clusters are optimized at the coupled-cluster singles doubles level of theory. The optical absorption spectra of these clusters are calculated using three wave-function-based methods, namely, configuration interaction singles, random phase approximation, and equation-of-motion coupled-cluster singles doubles (EOM-CCSD) as well as using a time-dependent density-functional-theory-based method using various hybrid and long-range-corrected exchange and correlation functionals. There is an ample variation in the optical absorption spectra computed using different density functionals. When compared to the EOM-CCSD spectrum, an excellent agreement is provided by CAM-B3LYP functional, followed by ωB97xD functional. PBE0, B3LYP, and B3PW91 functionals agree among each other. However, their spectra are red-shifted with respect to the EOM-CCSD counterpart. On the basis of the natural transition orbital analysis, the nature of optical excitation is also discussed.

Development and Validation of Chiral HPLC Method for Quantification of 3-(S)-Quinuclidinol in Pharmaceutically Important Precursor, 3-(R)-Quinuclidinol, by Precolumn Derivatization.

A sensitive and specific high-performance liquid chromatography (HPLC) method for the separation and quantification of 3-(S)-quinuclidinol in 3-(R)-quinuclidinol, precursor for active pharmaceutical ingredients (solifenacin, revatropate and talsaclidine), has been developed and validated by precolumn derivatization. Several chiral columns were tested in a normal phase system. Excellent enantioseparation with the resolution more than 11.4 was achieved on Chiralpak IC column using isocratic mobile phase consisting of n-hexane, ethanol, 2-propanol and diethylamine (80:8:12:0.4, v/v). The detection was carried out using UV detector at 230 nm. The influence of mobile phase composition, namely organic modifiers, additives, aliphatic alkanes and water content in mobile phase, on retention and enantioseparation was studied. Validation of the developed method including specificity, system suitability, limit of detection, limit of quantification, linearity, repeatability, intermediate precision, accuracy and solution stability was performed according to the International Conference on Harmonization guidelines. The advantage of the method is a good HPLC enantioseparation by precolumn derivatization using reaction mixture as sample, simpler UV detection, short analysis time (<30 min), and therefore this method is suitable option for routine quantification of 3-(S)-quinuclidinol in 3-(R)-quinuclidinol.

Rhino-orbital mucormycosis in diabetes mellitus.

Rhino-orbital mucormycosis is a rare but life threatening infection that generally occurs in patients with diabetes mellitus and other immune deficiency conditions. Rhino-orbital and Rhino-cerebral are two form of the disease. As such the condition is a medical emergency. Early recognition and treatment are essential because it may lead to death in few days. Fungal infection of nasal cavity is uncommon but is being seen with increasing frequency in patients with immune deficiency.