Acta Crystallogr B Struct Sci Cryst Eng Mater
April 2025
Pharmaceutical solid forms, like salts and cocrystals, play a crucial role in drug formulation. Despite differing mainly by a single hydrogen atom, the regulatory requirements set by the US Food and Drug Administration for these forms vary significantly. We previously developed a DFT-based computational method to distinguish salts from cocrystals.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
December 2024
The random-phase approximation (RPA) includes a subset of higher than second-order correlation-energy contributions, but stays in the same complexity class as the second-order Møller-Plesset perturbation theory (MP2) in both Gaussian-orbital and plane-wave codes. This makes RPA a promising ab initio electronic structure approach for the binding energies of molecular crystals. Still, some issues stand out in practical applications of RPA.
View Article and Find Full Text PDFJ Chem Theory Comput
December 2023
The projector-augmented wave (PAW) method is one of the approaches that are widely used to approximately treat core electrons and thus to speed up plane-wave basis set electronic structure calculations. However, PAW involves approximations, and it is thus important to understand how they affect the results. Tests of the precision of PAW data sets often use the properties of isolated atoms or atomic solids.
View Article and Find Full Text PDFFerrocene is perhaps the most popular and well-studied organometallic molecule, but our understanding of its structure and electronic properties has not changed for more than 70 years. In particular, all previous attempts of chemically oxidizing pure ferrocene by binding directly to the iron center have been unsuccessful, and no significant change in structure or magnetism has been reported. Using a metal organic framework host material, we were able to fundamentally change the electronic and magnetic structure of ferrocene to take on a never-before observed physically stretched/bent high-spin Fe(II) state, which readily accepts O from air, chemically oxidizing the iron from Fe(II) to Fe(III).
View Article and Find Full Text PDFThe relative energies of different phases or polymorphs of molecular solids can be small, less than a kilojoule/mol. A reliable description of such energy differences requires high-quality treatment of electron correlations, typically beyond that achievable by routinely applicable density functional theory (DFT) approximations. At the same time, high-level wave function theory is currently too computationally expensive.
View Article and Find Full Text PDFPrevalence of individual species, data evaluating their association with gastric pathology and comparison of accuracy of diagnostic techniques are limited. The aims of this study were to determine the prevalence of gastric species, their association with gastric pathology, and to compare diagnostic techniques. Gastric biopsies from 84 privately-owned dogs with chronic gastrointestinal signs were obtained endoscopically.
View Article and Find Full Text PDFThe many-body expansion (MBE) of energies of molecular clusters or solids offers a way to detect and analyze errors of theoretical methods that could go unnoticed if only the total energy of the system was considered. In this regard, the interaction between the methane molecule and its enclosing dodecahedral water cage, CH···(HO), is a stringent test for approximate methods, including density functional theory (DFT) approximations. Hybrid and semilocal DFT approximations behave erratically for this system, with three- and four-body nonadditive terms having neither the correct sign nor magnitude.
View Article and Find Full Text PDFPurpose: A national primary and secondary healthcare-level study in the Czech Republic has not yet been conducted to evaluate the prevalence of migraine. We analyzed the current treatment patterns (acute and prophylactic) in migraine patients and the number of migraine patients potentially eligible for treatment with recent calcitonin gene-related peptide (CGRP) pathway-targeted therapies.
Methods: This retrospective study utilized the Ministry of the Interior Health Insurance Fund claims database of the Czech Republic wherein every citizen is insured.
Various properties of water are affected by confinement as the space-filling of the water molecules is very different from bulk water. In our study, we challenged the creation of a stable system in which water molecules are permanently locked in nanodimensional graphene traps. For that purpose, we developed a technique, nitrocellulose-assisted transfer of graphene grown by chemical vapor deposition, which enables capturing of the water molecules below an atomically thin graphene membrane structured into a net of regular wrinkles with a lateral dimension of about 4 nm.
View Article and Find Full Text PDFAccurate theoretical methods are needed to correctly describe adsorption on solid surfaces or in porous materials. The random phase approximation (RPA) with singles corrections scheme and the second order Møller-Plesset perturbation theory (MP2) are two schemes, which offer high accuracy at affordable computational cost. However, there is little knowledge about their applicability and reliability for different adsorbates and surfaces.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2020
The random phase approximation (RPA) has received considerable interest in the field of modeling systems where noncovalent interactions are important. Its advantages over widely used density functional theory (DFT) approximations are the exact treatment of exchange and the description of long-range correlation. In this work, we address two open questions related to RPA.
View Article and Find Full Text PDFBackground: Chronic obstructive pulmonary disease (COPD) represents an illness with significant healthcare and societal impacts. Fixed combinations of long-acting beta-agonists (LABA) and inhaled corticosteroids have been used for COPD treatment as the standard of care for many years. A daily dose of indacaterol and glycopyrronium (IND/GLY) at 110/50 µg has recently been gaining attention due to its improved efficacy and tolerability versus the standard of care.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2018
Environ Sci Pollut Res Int
October 2017
Over the past decade, the environment has been polluted by a wide spectrum of exogenous chemicals and environmental analysis has become one of the most progressive parts of analytical research. The aim of this work was to determine the kinetics of natural degradation, and to identify the degradation products of the massively used estrogenic drug, 17-α-ethinylestradiol. The photodegradation, oxidation and thermostability conditions were selected according to ICH requirements for pharmaceutical stability testing.
View Article and Find Full Text PDFWe use the random phase approximation (RPA) method with the singles correlation energy contributions to calculate lattice energies of ten molecular solids. While RPA gives too weak binding, underestimating the reference data by 13.7% on average, much improved results are obtained when the singles are included at the GW singles excitations (GWSE) level, with average absolute difference to the reference data of only 3.
View Article and Find Full Text PDFBackground: Economic data pertaining to cystic fibrosis (CF), is limited in Europe generally, and completely lacking in Central and Eastern Europe. We performed an analysis of all direct costs associated with CF relative to key disease features and laboratory examinations.
Methods: A retrospective prevalence-based cost-of-illness (COI) study was performed in a representative cohort of 242 CF patients in the Czech Republic, which represents about 65 % of all Czech CF patients.
The random phase approximation to the correlation energy often yields highly accurate results for condensed matter systems. However, ways how to improve its accuracy are being sought and here we explore the relevance of singles contributions for prototypical solid state systems. We set out with a derivation of the random phase approximation using the adiabatic connection and fluctuation dissipation theorem, but contrary to the most commonly used derivation, the density is allowed to vary along the coupling constant integral.
View Article and Find Full Text PDF1. Purine cyclin-dependent kinase inhibitors have recently been recognised as promising candidates for the treatment of various cancers. While pharmacodynamic properties of these compounds are relatively well understood, their pharmacokinetics including possible interactions with placental transport systems have not been characterised to date.
View Article and Find Full Text PDFDinaciclib is a novel cyclin-dependent kinase inhibitor (CDKI) with significant activity against various cancers in vitro and in vivo. ABC efflux transporters play an important role in drug disposition and are responsible for multidrug resistance in cancer cells. Inhibitors and substrates of these transporters may participate in pharmacokinetic drug-drug interactions (DDIs) that alter drug disposition during pharmacotherapy.
View Article and Find Full Text PDFSalicylaldehyde isonicotinoyl hydrazone (SIH) is an intracellular iron chelator with well documented potential to protect against oxidative injury both in vitro and in vivo. However, it suffers from short biological half-life caused by fast hydrolysis of the hydrazone bond. Recently, a concept of boronate prochelators has been introduced as a strategy that might overcome these limitations.
View Article and Find Full Text PDFAntimicrobial resistance genes can be found in all ecosystems, including those where antibiotic selective pressure has never been exerted. We investigated resistance genes in a collection of faecal samples of wildlife (non-human primates, mice), people and domestic animals (dogs, cats) in Côte d'Ivoire; in the chimpanzee research area of Taï National Park (TNP) and adjacent villages. Single bacteria isolates were collected from antibiotic-containing agar plates and subjected to molecular analysis to detect Enterobacteriaceae isolates with plasmid-mediated genes of extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR).
View Article and Find Full Text PDFKnowledge about the intrinsic electronic properties of water is imperative for understanding the behaviour of aqueous solutions that are used throughout biology, chemistry, physics, and industry. The calculation of the electronic band gap of liquids is challenging, because the most accurate ab initio approaches can be applied only to small numbers of atoms, while large numbers of atoms are required for having configurations that are representative of a liquid. Here we show that a high-accuracy value for the electronic band gap of water can be obtained by combining beyond-DFT methods and statistical time-averaging.
View Article and Find Full Text PDFThe energetic barriers that atoms and molecules often experience when binding to surfaces are incredibly important to a myriad of chemical and physical processes. However, these barriers are difficult to describe accurately with current computer simulation approaches. Two prominent contemporary challenges faced by simulation are the role of van der Waals forces and nuclear quantum effects.
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