A Novel PAMAM G3 Dendrimer-Based Foam with Polyether Polyol and Castor Oil Components as Drug Delivery System into Cancer and Normal Cells.

One of the intensively developed tools for cancer therapy is drug-releasing matrices. Polyamidoamine dendrimers (PAMAM) are commonly used as nanoparticles to increase the solubility, stability and retention of drugs in the human body. Most often, drugs are encapsulated in PAMAM cavities or covalently attached to their surface.

Upper Extremity Musculoskeletal Injuries Presenting to an Emergency Department Before and During the Initial COVID-19 Pandemic Surge.

Study Objective: The SARS-CoV-2 (COVID-19) pandemic significantly impacted emergency department volume and acuity. The Delta and Omicron variants contributed to additional surges. We describe the impact that the initial pandemic phase had on frequency and severity of typically non-life-threatening emergencies using upper extremity injuries as a model for other potentially emergent presentation as compared to pre-pandemic times.

The four-component DFT method for the calculation of the EPR g-tensor using a restricted magnetically balanced basis and London atomic orbitals.

Four-component relativistic treatments of the electron paramagnetic resonance g-tensor have so far been based on a common gauge origin and a restricted kinetically balanced basis. The results of such calculations are prone to exhibit a dependence on the choice of the gauge origin for the vector potential associated with uniform magnetic field and a related dependence on the basis set quality. In this work, this gauge problem is addressed by a distributed-origin scheme based on the London atomic orbitals, also called gauge-including atomic orbitals (GIAOs), which have proven to be a practical approach for calculations of other magnetic properties.

A free boratriptycene-type Lewis superacid.

Bicyclic pyrazabole-bridged ferrocenes with BH groups at their bridgehead positions were prepared from [Li(thf)][1,1'-fc(BH)] and pyrazole or 3,5-dimethylpyrazole in the presence of MeSiCl (1 or 1Me, respectively; 1,1'-fc = 1,1'-ferrocenylene); MeSiH and H are released as byproducts. Treatment of 1 or 1Me with 1 eq. of the hydride scavenger [PhC][B(CF)] afforded the borenium salts [2][B(CF)] (72%) and [2Me][B(CF)] (77%).

Clinical Response to Celiac Plexus Block Confirms the Neurogenic Etiology of Median Arcuate Ligament Syndrome.

Purpose: To evaluate the response of median arcuate ligament syndrome (MALS) symptoms, including postprandial pain, nausea, and vomiting, to celiac plexus block (CPB) and correlate the response with arterial anatomy.

Materials And Methods: In a single-institution, retrospective cohort of clinically diagnosed MALS patients, 96 patients (female, 75; male, 21; mean age, 27 years) underwent 103 computed tomography‒guided percutaneous CPB procedures. Imaging, procedural, and clinical reports were reviewed.

Doubly Occupied Pair Coupled Cluster F12 Approach.

Inspired by reports of the good performance of the doubly occupied pair coupled cluster (pCCD) theory in describing static electron correlation, we have introduced and implemented a variant thereof that includes single excitations and explicitly treats the dynamic electron correlation using the F12 methodology (pCCSD-F12). This drastically reduces the computation scaling with respect to the standard method using the full double-excitation operator (CCSD-F12). Slater-type geminals as a correlation factor, together with fixed cusp conditions, were used, which is known as the -ansatz.

4-Factor Prothrombin Complex Concentrate Administration via Intraosseous Access for Urgent Reversal of Warfarin.

Background: Vitamin K antagonist (VKA) reversal in patients with acute major bleeding and coagulopathy is an example of an urgent intervention in the emergency department. Intravenous (IV) prothrombin complex concentrate (PCC) may reverse VKA-induced coagulopathy in <30 min. In patients lacking IV access, effective PCC administration becomes problematic.

Assessment of Employee Susceptibility to Phishing Attacks at US Health Care Institutions.

Importance: Cybersecurity is an increasingly important threat to health care delivery, and email phishing is a major attack vector against hospital employees.

Objective: To describe the practice of phishing simulation and the extent to which health care employees are vulnerable to phishing simulations.

Design, Setting, And Participants: Retrospective, multicenter quality improvement study of a convenience sample of 6 geographically dispersed US health care institutions that ran phishing simulations from August 1, 2011, through April 10, 2018.

Implementation of the diagonalization-free algorithm in the self-consistent field procedure within the four-component relativistic scheme.

A recently developed Thouless-expansion-based diagonalization-free approach for improving the efficiency of self-consistent field (SCF) methods (Noga and Šimunek, J. Chem. Theory Comput.

An explicitly correlated Mukherjee's state specific coupled cluster method: development and pilot applications.

This paper reports development of the explicitly correlated variant of Mukherjee's state specific multireference coupled cluster method (MkCC-F12). The current implementation is restricted to conventional single and double excitations and to pseudo-double excitations related to the Slater Type Geminal (STG) correlation factor using the SP ansatz. The performance of the MkCCSD-F12 was tested on calculations of singlet methylene, dissociation curve of the fluorine molecule, and the BeH(2) insertion pathway.

Communication: convergence of anharmonic infrared intensities of hydrogen fluoride in traditional and explicitly correlated coupled cluster calculations.

It is shown that the convergence of anharmonic infrared spectral intensities with respect to the basis set size is much enhanced in explicitly correlated calculations as compared to traditional configuration interaction type wave function expansion. Explicitly correlated coupled cluster (CC) calculations using Slater-type geminal correlation factor (CC-F12) yield well-converged dipole derivatives and vibrational intensities for hydrogen fluoride with basis set involving f functions on the heavy atom. Combination of CC-F12 with singles, doubles, and non-iterative triples (CCSD(T)-F12) with small corrections due to quadruple excitations, core-electron correlation, and relativistic effects yields vibrational line positions, dipole moments, and transition dipole matrix elements in good agreement with the best experimental values.

Acceleration of self-consistent-field convergence by combining conventional diagonalization and a diagonalization-free procedure.

A new scheme that combines conventional matrix diagonalization with the recently proposed diagonalization-free algorithm has been developed to obtain the density matrix for the next self-consistent-field iteration from the Fock matrix of the current iteration. In this manner, the advantages of the two methods are combined. The more rapid convergence of the diagonalization-free algorithm for density matrices rather close to self consistence and the more robust convergence of the conventional matrix diagonalization further away from self-consistence.

Solving the Independent-Particle Model via Nonunitary Transformation Based on Variational Coupled Cluster Singles.

We propose an alternative new approach to obtain the Slater determinant ground state solution within an independent-particle approximation using the exponential ansatz for the wave function (Thouless theorem) and exact treatment in terms of variational coupled cluster singles. Although the resulting nonlinear equations formally represent nonterminating expansions, these can be reformulated to finite expansions in terms of the density matrix correction. The latter can be exactly calculated using a very simple recurrence relation within the occupied-occupied block, while the complementary occupied-virtual and virtual-virtual blocks are related and trivially obtained by subsequent matrix multiplications involving the amplitudes of the single-excitation operator.

Anharmonic vibrational analysis of water with traditional and explicitly correlated coupled cluster methods.

It is well known that the convergence of harmonic frequencies with respect to the basis set size in traditional correlated calculations is slow. We now report that the convergence of cubic and quartic force constants in traditional CCSD(T) calculations on H(2)O with Dunning's cc-pVXZ family of basis sets is also frustratingly slow. As an alternative, we explore the performance of R12-based explicitly correlated methods at the CCSD(T) level.

R12-calibrated H2O-H2 interaction: full dimensional and vibrationally averaged potential energy surfaces.

The potential energy surface of H(2)O-H(2) is of great importance for quantum chemistry as a test case for H(2)O-molecule interactions. It is also required for a detailed understanding of important astrophysical processes, namely, the collisional excitation of water, including the pumping of water masers and the formation of molecular hydrogen on icy interstellar dust grains. We have calculated the interaction for H(2)O-H(2) by performing both rigid-rotor (five-dimensional) and non-rigid-rotor (nine-dimensional) calculations using the coupled-cluster theory at the level of singles and doubles with perturbative corrections for triple excitations [CCSD(T)] with moderately large but thoroughly selected basis set.

Implementation of the CCSD(T)-F12 method using cusp conditions.

The explicitly-correlated coupled-cluster singles and doubles with perturbative triples method (CCSD(T)-F12) is implemented using the cusp conditions. Numerical tests for a set of 16 molecules have shown agreement of correlation energies within 1 mE(h) between the cusp-condition and fully-optimized CCSD(T)-F12 methods. Benchmark calculations on 13 chemical reactions with the cusp-condition CCSD(T)-F12 method reproduce experimental enthalpies within 2 kJ mol(-1).

Explicitly correlated coupled cluster F12 theory with single and double excitations.

Full explicitly correlated F12 coupled cluster theory with single and double excitations and with Slater-type geminal as a correlation factor is introduced and implemented within the standard approximation. The variant "C" that does not require integrals over the commutator between the kinetic operator and the correlation factor has been used. All the necessary integrals are analytically calculated.

Second order explicitly correlated R12 theory revisited: a second quantization framework for treatment of the operators' partitionings.

Second order R12 theory is presented and derived alternatively using the second quantized hole-particle formalism. We have shown that in order to ensure the strong orthogonality between the R12 and the conventional part of the wave function, the explicit use of projection operators can be easily avoided by an appropriate partitioning of the involved operators to parts which are fully describable within the computational orbital basis and complementary parts that involve imaginary orbitals from the complete orbital basis. Various Hamiltonian splittings are discussed and computationally investigated for a set of nine molecules and their atomization energies.

Convergence of third order correlation energy in atoms and molecules.

We have investigated the convergence of third order correlation energy within the hierarchies of correlation consistent basis sets for helium, neon, and water, and for three stationary points of hydrogen peroxide. This analysis confirms that singlet pair energies converge much slower than triplet pair energies. In addition, singlet pair energies with (aug)-cc-pVDZ and (aug)-cc-pVTZ basis sets do not follow a converging trend and energies with three basis sets larger than aug-cc-pVTZ are generally required for reliable extrapolations of third order correlation energies, making so the explicitly correlated R12 calculations preferable.

Density fitting of two-electron integrals in extended systems with translational periodicity: the Coulomb problem.

Density fitting approach to Coulomb integrals for infinite systems with translational periodicity is reformulated in direct space. Despite of the Coulomb infinite decay of some integrals, direct-space calculation is shown to be feasible. Moreover, we show that the direct-space ansatz is completely equivalent to our previous formulation in reciprocal space.

A full nine-dimensional potential-energy surface for hydrogen molecule-water collisions.

The hydrogen and water molecules are ubiquitous in the Universe. Their mutual collisions drive water masers and other line emission in various astronomical environments, notably molecular clouds and star-forming regions. We report here a full nine-dimensional interaction potential for H2O-H2 calibrated using high-accuracy, explicitly correlated wave functions.

Accurate quantum-chemical prediction of enthalpies of formation of small molecules in the gas phase.

The coupled-cluster approach, including single and double excitations and perturbative corrections for triple excitations, is capable of predicting molecular electronic energies and enthalpies of formation of small molecules in the gas phase with very high accuracy (specifically, with error bars less than 5 kJmol-1), provided that the electronic wavefunction is dominated by the Hartree-Fock configuration. This capability is illustrated by calculations on molecules containing O-H and O-F bonds, namely OH, FO, H2O, HOF, and F2O. To achieve this very high accuracy, it is imperative to account for electron-correlation effects in a quantitative manner, either by using explicitly correlated two-particle basis functions (R12 functions) or by extrapolating to the limit of a complete basis.