Dispersion Energies with the i-DMFT Method.

The recently proposed i-DMFT method [Wang and Baerends, 013001 (2022)] has been proven to be ideally suited to recover strong static correlation in dissociating covalent bonds. Here, the application to van der Waals bonding is investigated using the prototype van der Waals systems triplet H and ground-state He. It is demonstrated that the i-DMFT orbitals are in this case essentially different from the natural orbitals, and the i-DMFT occupations differ substantially from the NO occupations.

Development of antibody levels and subsequent decline in individuals with vaccine induced and hybrid immunity to SARS-CoV-2.

Objectives: This study aimed to compare antibody trajectories among individuals with SARS-CoV-2 hybrid and vaccine-induced immunity.

Methods: Danish adults receiving three doses of BTN162b2 or mRNA-1237 were included prior to first vaccination (Day 0). SARS-CoV-2 anti-spike IgG levels were assessed before each vaccine dose, at Day 90, Day 180, 28 days after 3rd vaccination (Day 251), Day 365, and prior to 4th vaccination (Day 535).

Longitudinal Evaluation of Severe Acute Respiratory Syndrome Coronavirus 2 T-Cell Immunity Over 2 Years Following Vaccination and Infection.

Background: Within a year of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, vaccines inducing a robust humoral and cellular immune response were implemented worldwide. However, emergence of novel variants and waning vaccine-induced immunity led to implementation of additional vaccine boosters.

Methods: This prospective study evaluated the temporal profile of cellular and serological responses in a cohort of 639 SARS-CoV-2-vaccinated participants, of whom a large proportion experienced a SARS-CoV-2 infection.

Efficacy of cola ingestion for oesophageal food bolus impaction: open label, multicentre, randomised controlled trial.

Objective: To determine the efficacy and safety of cola in resolving complete oesophageal food bolus impaction.

Design: Open label, multicentre, randomised controlled trial.

Setting: Emergency departments of five Dutch hospitals at the secondary and tertiary level, between 22 December 2019 and 16 June 2022.

SARS-CoV-2 vaccine-induced antibodies protect against Omicron breakthrough infection.

SARS-CoV-2 Omicron quickly spread globally, also in regions with high vaccination coverage, emphasizing the importance of exploring the immunological requirements for protection against Omicron breakthrough infection. The test-negative matched case-control study (N = 964) characterized Omicron breakthrough infections in triple-vaccinated individuals from the ENFORCE cohort. Within 60 days before a PCR test spike-specific IgG levels were significantly lower in cases compared to controls (GMR [95% CI] for BA.

Omicron Variant-Specific Serological Imprinting Following BA.1 or BA.4/5 Bivalent Vaccination and Previous SARS-CoV-2 Infection: A Cohort Study.

Background: Continuous evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outpaces monovalent vaccine cross-protection to new viral variants. Consequently, bivalent coronavirus disease 2019 (COVID-19) vaccines including Omicron antigens were developed. The contrasting immunogenicity of the bivalent vaccines and the impact of prior antigenic exposure on new immune imprinting remains to be clarified.

Impact of age and comorbidities on SARS-CoV-2 vaccine-induced T cell immunity.

Background: Older age and chronic disease are important risk factors for developing severe COVID-19. At population level, vaccine-induced immunity substantially reduces the risk of severe COVID-19 disease and hospitalization. However, the relative impact of humoral and cellular immunity on protection from breakthrough infection and severe disease is not fully understood.

DFT exchange: sharing perspectives on the workhorse of quantum chemistry and materials science.

In this paper, the history, present status, and future of density-functional theory (DFT) is informally reviewed and discussed by 70 workers in the field, including molecular scientists, materials scientists, method developers and practitioners. The format of the paper is that of a roundtable discussion, in which the participants express and exchange views on DFT in the form of 302 individual contributions, formulated as responses to a preset list of 26 questions. Supported by a bibliography of 777 entries, the paper represents a broad snapshot of DFT, anno 2022.

Comparison of vaccine-induced antibody neutralization against SARS-CoV-2 variants of concern following primary and booster doses of COVID-19 vaccines.

The SARS-CoV-2 pandemic has, as of July 2022, infected more than 550 million people and caused over 6 million deaths across the world. COVID-19 vaccines were quickly developed to protect against severe disease, hospitalization and death. In the present study, we performed a direct comparative analysis of four COVID-19 vaccines: BNT162b2 (Pfizer/BioNTech), mRNA-1273 (Moderna), ChAdOx1 (Oxford/AstraZeneca) and Ad26.

Modeling the early stages of Alzheimer's disease by administering intracerebroventricular injections of human native Aβ oligomers to rats.

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease characterized by the accumulation of aggregated amyloid beta (Aβ) and hyperphosphorylated tau along with a slow decline in cognitive functions. Unlike advanced AD, the initial steps of AD pathophysiology have been poorly investigated, partially due to limited availability of animal models focused on the early, plaque-free stages of the disease. The aim of this study was to evaluate the early behavioral, anatomical and molecular alterations in wild-type rats following intracerebroventricular injections of human Aβ oligomers (AβOs).

Secondary Kinetic Peak in the Kohn-Sham Potential and Its Connection to the Response Step.

We consider a prototypical 1D model Hamiltonian for a stretched heteronuclear molecule and construct individual components of the corresponding KS potential, namely, the kinetic, the - 1, and the conditional potentials. These components show very special features, such as peaks and steps, in regions where the density is drastically low. Some of these features are quite well-known, whereas others, such as a secondary peak in the kinetic potential or a second bump in the conditional potential, are less or not known at all.

Chemical potential, derivative discontinuity, fractional electrons, jump of the Kohn-Sham potential, atoms as thermodynamic open systems, and other (mis)conceptions of the density functional theory of electrons in molecules.

Many references exist in the density functional theory (DFT) literature to the chemical potential of the electrons in an atom or a molecule. The origin of this notion has been the identification of the Lagrange multiplier = ∂/∂ in the Euler-Lagrange variational equation for the ground state density as the chemical potential of the electrons. We first discuss why the Lagrange multiplier in this case is an arbitrary constant and therefore cannot be a physical characteristic of an atom or molecule.

Self-Consistent-Field Method for Correlated Many-Electron Systems with an Entropic Cumulant Energy.

A self-consistent field method is presented within density matrix functional theory. The computational cost for a correlated many-electron calculation is reduced to that of the self-consistent-field Hartree-Fock method, while the accuracy still reaches that of sophisticated configuration interaction based methods. In this method, the two-electron cumulant energy is measured with an information entropy associated with the Fermi-Dirac distribution of the occupation numbers.

Origin of the Enhanced Binding Capability toward Axial Nitrogen Bases of Ni(II) Porphyrins Bearing Electron-Withdrawing Substituents: An Electronic Structure and Bond Energy Analysis.

Axial coordination to metalloporphyrins is important in many biological and catalytic processes. Experiments found the axial coordination of nitrogenous bases to nickel(II) porphyrins to be strongly favored by electron-withdrawing substituents such as perfluorophenyls at the meso carbon positions. Careful analysis of the electronic structure reveals that the natural explanation in terms of density change of the nickel(II) porphyrin system (in particular the metal), does not apply.

The Electron Affinity as the Highest Occupied Anion Orbital Energy with a Sufficiently Accurate Approximation of the Exact Kohn-Sham Potential.

Negative ions are not accurately represented in density functional approximations (DFAs) such as (semi)local density functionals (LDA or GGA or meta-GGA). This is caused by the much too high orbital energies (not negative enough) with these DFAs compared to the exact Kohn-Sham values. Negative ions very often have positive DFA HOMO energies, hence they are unstable.

Cola therapy for oesophageal food bolus impactions a case series.

Introduction: This retrospective case series describes the use of cola to immediately treat complete oesophageal food bolus obstructions in the emergency centre. Short of emergent endoscopy - which is invasive, expensive, not without adverse events, and often unavailable in low-resource settings - no other proven therapies exist to relieve oesophageal food impactions.

Methods: We performed a chart review of adults with complete oesophageal food bolus obstructions presenting to two Dutch emergency centres.

Density functional approximations for orbital energies and total energies of molecules and solids.

The relation of Kohn-Sham (KS) orbital energies to ionization energies and electron affinities is different in molecules and solids. In molecules, the local density approximation (LDA) and generalized gradient approximations (GGA) approximate the exact ionization energy (I) and affinity (A) rather well with self-consistently calculated (total energy based) I and A, respectively. The highest occupied molecular orbital (HOMO) energy and lowest unoccupied molecular orbital (LUMO) energy, however, differ significantly (by typically 4-6 eV) from these quantities, ϵ(mol)>-I(mol)≈-I(mol), ϵ(mol)<-A(mol)≈-A(mol).

Comparing dual energy CT and subtraction CT on a phantom: which one provides the best contrast in iodine maps for sub-centimetre details?

Objectives: To compare contrast-to-noise ratios (CNRs) and iodine discrimination thresholds on iodine maps derived from dual energy CT (DECT) and subtraction CT (SCT).

Methods: A contrast-detail phantom experiment was performed with 2 to 15 mm diameter tubes containing water or iodinated contrast concentrations ranging from 0.5 mg/mL to 20 mg/mL.

[Consult Online: digital resource for tropical doctors].

Consult Online is a Dutch telemedicine system for physicians who work in international healthcare and tropical medicine (formerly known as 'tropical doctors'). It provides specialist advice for complicated cases where local specialist services are lacking. Eighty-nine experts from 25 different specialties are available for advice via www.

A non-JKL density matrix functional for intergeminal correlation between closed-shell geminals from analysis of natural orbital configuration interaction expansions.

Almost all functionals that are currently used in density matrix functional theory have been created by some a priori ansatz that generates approximations to the second-order reduced density matrix (2RDM). In this paper, a more consistent approach is used: we analyze the 2RDMs (in the natural orbital basis) of rather accurate multi-reference configuration interaction expansions for several small molecules (CH, NH, HO, FH, and N) and use the knowledge gained to generate new functionals. The analysis shows that a geminal-like structure is present in the 2RDMs, even though no geminal theory has been applied from the onset.

[A Papua New Guinean with three foot ulcers].

A 25-year-old Papuan presented with three painless foot ulcers with undermined edges, induration and oedema. The appearance was typical for Buruli ulcer, which is caused by Mycobacterium ulcerans. A smear was positive for acid fast bacilli.

Paediatric procedural sedation and analgesia by emergency physicians in a country with a recent establishment of emergency medicine.

Objectives: Paediatric patients receive less procedural sedation and analgesia (PSA) in the emergency department compared with adults, especially in countries where emergency medicine is at an early stage of development. The objectives of this study were to evaluate the adverse events and efficacy of paediatric PSA in a country with a recent establishment of emergency medicine and to describe which factors aided implementation.

Methods: This is a prospective, multicentre, observational study of paediatric patients undergoing PSA by the first trained emergency physicians (EPs) in The Netherlands.

From the Kohn-Sham band gap to the fundamental gap in solids. An integer electron approach.

It is often stated that the Kohn-Sham occupied-unoccupied gap in both molecules and solids is "wrong". We argue that this is not a correct statement. The KS theory does not allow to interpret the exact KS HOMO-LUMO gap as the fundamental gap (difference (I - A) of electron affinity (A) and ionization energy (I), twice the chemical hardness), from which it indeed differs, strongly in molecules and moderately in solids.

Natural excitation orbitals from linear response theories: Time-dependent density functional theory, time-dependent Hartree-Fock, and time-dependent natural orbital functional theory.

Straightforward interpretation of excitations is possible if they can be described as simple single orbital-to-orbital (or double, etc.) transitions. In linear response time-dependent density functional theory (LR-TDDFT), the (ground state) Kohn-Sham orbitals prove to be such an orbital basis.