Positioning of grid points for spanning potential energy surfaces-How much effort is really needed?

The positions of grid points for representing a multidimensional potential energy surface (PES) have a non-negligible impact on its accuracy and the associated computational effort for its generation. Six different positioning schemes were studied for PESs represented by n-mode expansions as needed for the accurate calculation of anharmonic vibrational frequencies by means of vibrational configuration interaction theory. A static approach, which has successfully been used in many applications, and five adaptive schemes based on Gaussian process regression have been investigated with respect to the number of necessary grid points and the accuracy of the fundamental modes for a small set of test molecules.

Geometry Optimization in Internal Coordinates Based on Gaussian Process Regression: Comparison of Two Approaches.

Geometry optimization based on Gaussian process regression (GPR) was extended to internal coordinates. We used delocalized internal coordinates composed of distances and several types of angles and compared two methods of including them. In both cases, the GPR surrogate surface is trained on geometries in internal coordinates.

Evaporation and Fragmentation of Organic Molecules in Strong Electric Fields Simulated with DFT.

Atom probe tomography allows us to measure the three-dimensional composition of materials with up to atomic resolution by evaporating the material using high electric fields. Initially developed for metals, it is increasingly used for covalently bound structures. To aid the interpretation of the obtained fragmentation pattern, we modeled the fragmentation and desorption of self-assembled monolayers of thiolate molecules on a gold surface in strong electrostatic fields using density functional theory.

Pregnancy-associated spontaneous coronary artery dissection: insights from a case series of 13 patients.

Aims: We sought to present a series of 13 pregnancy-associated spontaneous coronary artery dissection (P-SCAD), their angiographic and multimodal imaging findings, acute phase treatment, and outcomes.

Methods And Results: Between 2005 and 2015, 13 cases of P-SCAD were collected from a database of 11 tertiary hospitals. The mean age was 33.

The Impact of Cardiac Diseases during Pregnancy on Severe Maternal Morbidity and Mortality in Brazil.

Background: To evaluate maternal heart disease as a cause or complicating factor for severe morbidity in the setting of the Brazilian Network for Surveillance of Severe Maternal Morbidity.

Methods And Findings: Secondary data analysis of this multicenter cross-sectional study was implemented in 27 referral obstetric units in Brazil. From July 2009 to June 2010, a prospective surveillance was conducted among all delivery hospitalizations to identify cases of severe maternal morbidity (SMM), including Potentially Life-Threatening Conditions (PLTC) and Maternal Near Miss (MNM), using the new criteria established by the WHO.

Pregnancy follow-up and outcome in a patient with Takayasu's arteritis.

We describe here the pregnancy follow-up and outcome in a patient with Takayasu's arteritis, with a detailed account of the complications during gestation and delivery and the impact of the disease on the newborn's health.

[Transient ventricular dysfunction (Takotsubo cardiomyopathy)].

The patient was a male with myasthenia gravis, hospitalized with acute respiratory failure due to decompensation of the underlying disease. He evolved with findings suggestive of acute myocardial infarction, with electrocardiographic and enzymatic alterations compatible with that diagnosis. The patient underwent emergency coronary angiography, which showed no severe coronary obstruction, although his left ventricle had significant systolic dysfunction with characteristic alterations, on ventriculography, of the syndrome described as transient ventricular dysfunction or Takotsubo syndrome.