Optimized Basis Sets for the Environment in the Domain-Specific Basis Set Approach of the Incremental Scheme

Minimal basis sets, denoted DSBSenv, have been developed based on the segmented basis sets of Ahlrichs and co-workers for use as environmental basis set for the domain-specific basis set incremental scheme with the aim of decreasing the CPU requirements of the incremental scheme. The use of this minimal basis within explicitly correlated (F12) methods has been enabled by the optimization of matching auxiliary basis sets for use in density fitting of two-electron integrals and the resolution-of-the-identity. The accuracy of these auxiliary sets has been validated by calculations on a test set containing small- to medium-sized molecules. The errors due to density fitting are about two to four orders of magnitude smaller than the basis set incompleteness error of the DSBSenv orbital basis sets. Additional reductions in computational cost are tested with the reduced DSBSenv basis sets, where the highest angular momentum functions of the DSBSenv auxiliary basis sets have been removed. The optimized and reduced basis sets are used in the framework of the domain-specific basis set of the incremental scheme to decrease the computation time without significant loss of accuracy. The computation times and accuracy of the previously used environmental basis and that optimized in this work is validated with a test set of medium- to large-sized systems. The optimized and reduced DSBSenv basis sets decrease the CPU-time by about 15.4% and 19.4% compared to the old environmental basis and retains the accuracy in the absolute energy with a standard deviation of 0.99 and 1.06 kJ/mol, respectively

Effects of Attention-Deficit/Hyperactivity Disorder on Patients Undergoing Percutaneous Coronary Intervention Procedure: Insights from the National Inpatient Sample

Introduction: Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that can affect children and adults and is characterized by deficits in attention, self-regulation, and executive functioning. Symptoms can seriously affect daily functioning and may present as hyperactivity, inattentive behaviors, or a combination of both. There are data to suggest patients with ADHD suffer from increased rates of cardiovascular disease, however not much is known specifically regarding the relationship between ADHD and undergoing Percutaneous Coronary Intervention. We sought to examine this relationship in greater detail by perusing the national inpatient sample database to describe in-hospital trends and outcomes among these patients. Methods: Data were extracted from the National Inpatient Sample (NIS) Database for the years 2019 and 2020. The NIS was searched for hospitalizations of adult patients who underwent Percutaneous Coronary Intervention. Out of this Cohort, ADHD patients were identified. Multivariate logistic was used to adjust for confounders. Results: This study included 181,944 patients who underwent PCI procedure, of which 518 (0.3%) patients were diagnosed with ADHD. ADHD patients who underwent a PCI procedure had higher prevalence of hypertension (40.1%% Vs 35.7%% p Conclusion: In this nationally representative population‐based retrospective cohort study, ADHD was associated with worse outcomes including developing arrhythmia, acute kidney injury and congestive heart failure exacerbation among patients who underwent PCI. We did not find any statistical difference between the two groups when it came to mortality, length of stay and total hospital charges. This is most likely due to the small sample size of patients with ADHD undergoing PCI. More research is needed in this area

Effects of NSTEMI on Patients with Eating Disorders: Insights from the National Inpatient Sample

Introduction: Eating disorders (ED) such as bulimia and anorexia nervosa have detrimental implications on the health and wellbeing of children and young adults across the country. Cardiovascular implications are known to accompany these conditions, however there is a paucity of data looking specifically on the effects of NSTEMI on patients with these disorders. We sought to analyze this relationship further by examining these disorders within the national inpatient sample database to describe in-hospital trends and outcomes among those patients. Methods: Data were extracted from the National Inpatient Sample (NIS) Database for the years 2019 and 2020. The NIS was searched for hospitalizations of adult patients with eating disorder(s) with and without a concomitant diagnosis of NSTEMI using international classification of diseases-10th revision codes. Multivariate logistic was used to adjust for confounders. The primary outcome was inpatient mortality. Secondary outcomes were hospital length of stay (LOS), and total hospital charges (TOTHCG). SPSS software was used for statistical analysis. Results: This study included 16,889 patients who were diagnosed with eating disorders, of which only 56 (0.3%) patients were diagnosed with NSTEMI. ED patients with NSTEMI had higher prevalence of hypertension, diabetes mellitus and chronic kidney disease but not statistically different compared to patients with ED only. Multivariate regression showed that patients with both ED and NSTEMI had higher inpatient mortality compared to those with ED alone (OR 1.013, CI 1.011-1.015, p Conclusion: In this nationally representative population‐based retrospective cohort study, we concluded that ED patients hospitalized with NSTEMI have increased in-hospital mortality and worse outcomes. More research is needed in this area

Outcomes of Thoracic Endovascular Aortic Repair (TEVAR) Procedure in Octogenarians, Nonagenarians and Centenarians: A Population-Based Study

Introduction: Limited data exists for patients undergoing a thoracic endovascular aortic repair (TEVAR) procedure who are older than or equal to 80 years old (YO). This study sought to examine the national inpatient sample (NIS) database to describe in-hospital outcomes among these older patients. Methods: The NIS was searched for hospitalizations of adults who underwent a TEVAR procedure in 2019 and 2020. The study compared those aged 80 YO and over to those younger than 80 YO. The primary outcome was inpatient mortality. Secondary outcomes included hospital length of stay (LOS), and total hospital charges (TOTHCG). Results: This study included 696 patients who underwent TEVAR, of which 35 (5.02%) were 80 years or older. Patients who had a TEVAR and were 80 years and older had higher prevalence of hypertension (57.6% vs. 50.3%, p Conclusion: In this nationally representative population‐based study, aging was associated with higher mortality and worse outcomes among patients undergoing a TEVAR procedure

Sex Differences in Outcomes Among Patients Undergoing Thoracic Endovascular Aortic Repair (TEVAR) Procedure: A Retrospective Cohort Study

Introduction: There is limited data about sex differences in patients undergoing a thoracic endovascular aortic repair (TEVAR) procedure. This study sought to examine the national inpatient sample (NIS) database to describe in-hospital outcomes by gender. Methods: The NIS was searched for hospitalizations of adult patients who underwent TEVAR in 2019 and 2020. For this cohort, female patients were identified, and pregnant patients were excluded. The primary outcome was inpatient mortality. Secondary outcomes included hospital length of stay (LOS), and total hospital charges (TOTHCG). Results: This study included 696 patients who underwent TEVAR. 255 (36.6%) females were identified, of which, 7 were pregnant and excluded from the study. Female patients who underwent TEVAR had higher prevalence of obesity (30.6% vs. 24.3%, p \u3c0.001), smoking (28.1% vs. 22.3%, p \u3c0.001), and CKD (5.2% vs. 4.2%, p \u3c0.001). In-hospital mortality was higher among the female cohort (6.1% vs. 4.0%, p \u3c 0.001). On multivariable regression, females who underwent TEVAR were associated with higher odds of inpatient mortality (OR 1.210, 95% CI 1.091-1.342, p \u3c0.001). Additionally, patients who underwent TEVAR and had ventricular arrythmias pay significantly more TOTHCG ($600,004 vs.$462,216, P\u3c0.001) with longer LOS (23.5days vs. 15.7days, p \u3c0.001). On secondary analysis it has shown patients with ventricular arrhythmias who underwent TEVAR had higher odds of having acute kidney injury, developing shock, arrhythmias and congestive heart failure exacerbation. Conclusion: In this nationally representative population‐based retrospective cohort study, female patients were associated with higher mortality and worse outcomes among patients undergoing TEVAR procedure

Clinical Outcomes for VA-ECMO Patients Associated with Hyperlipidemia: An Analysis of the National Inpatient Sample

Introduction: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is considered the most advanced temporary life support which provides complete hemodynamic support in addition to gas exchange. There is limited data available on the impact of hyperlipidemia (HLD) on VA-ECMO patients. We sought to examine the national inpatient sample (NIS) database to describe in-hospital outcomes among these patients. Methods: The NIS was searched for hospitalizations of adult VA-ECMO patients with and without a concomitant diagnosis of HLD for the years 2019 and 2020. The primary outcome was inpatient mortality. Results:This study included 3,885 VA-ECMO patients, of which 1,082 (27.8%) patients had HLD. VA-ECMO patients with HLD had higher prevalence of hypertension (57.3% vs. 71.4%, p Conclusion: In this nationally representative population‐based retrospective cohort study, HLD was associated with higher mortality and worse outcomes among VA-ECMO patients

Incremental Scheme for Open-Shell Systems

In this thesis, the implementation of the incremental scheme for open-shell systems with unrestricted Hartree-Fock reference wave functions is described. The implemented scheme is tested within robustness and performance with respect to the accuracy in the energy and the computation times. New approaches are discussed to implement a fully automated incremental scheme in combination with the domain-specific basis set approximation. The alpha Domain Partitioning and Template Equalization are presented to handle unrestricted wave functions for the local correlation treatment. Both orbital schemes are analyzed with a test set of structures and reactions. As a further goal, the DSBSenv orbital basis sets and auxiliary basis sets are optimized to be used as environmental basis in the domain-specific basis set approach. The performance with respect to the accuracy and computation times is analyzed with a test set of structures and reactions. In another project, a scheme for the optimization of auxiliary basis sets for uranium is presented. This scheme was used to optimize the MP2Fit auxiliary basis sets for uranium. These auxiliary basis enable density fitting in quantum chemical methods and the application of the incremental scheme for systems containing uranium. Another project was the systematical analysis of the binding energies of four water dodecamers. The incremental scheme in combination with the CCSD(T) and CCSD(T)(F12*) method were used to calculate benchmark energies for these large clusters

First UHF Implementation of the Incremental Scheme for Open-Shell Systems

The incremental scheme makes it possible to compute CCSD­(T) correlation energies to high accuracy for large systems. We present the first extension of this fully automated black-box approach to open-shell systems using an Unrestricted Hartree–Fock (UHF) wave function, extending the efficient domain-specific basis set approach to handle open-shell references. We test our approach on a set of organic and metal organic structures and molecular clusters and demonstrate standard deviations from canonical CCSD­(T) values of only 1.35 kJ/mol using a triple ζ basis set. We find that the incremental scheme is significantly more cost-effective than the canonical implementation even for relatively small systems and that the ease of parallelization makes it possible to perform high-level calculations on large systems in a few hours on inexpensive computers. We show that the approximations that make our approach widely applicable are significantly smaller than both the basis set incompleteness error and the intrinsic error of the CCSD­(T) method, and we further demonstrate that incremental energies can be reliably used in extrapolation schemes to obtain near complete basis set limit CCSD­(T) reaction energies for large systems

Optimized Basis Sets for the Environment in the Domain-Specific Basis Set Approach of the Incremental Scheme

Minimal basis sets, denoted DSBSenv, based on the segmented basis sets of Ahlrichs and co-workers have been developed for use as environmental basis sets for the domain-specific basis set (DSBS) incremental scheme with the aim of decreasing the CPU requirements of the incremental scheme. The use of these minimal basis sets within explicitly correlated (F12) methods has been enabled by the optimization of matching auxiliary basis sets for use in density fitting of two-electron integrals and resolution of the identity. The accuracy of these auxiliary sets has been validated by calculations on a test set containing small- to medium-sized molecules. The errors due to density fitting are about 2–4 orders of magnitude smaller than the basis set incompleteness error of the DSBSenv orbital basis sets. Additional reductions in computational cost have been tested with the reduced DSBSenv basis sets, in which the highest angular momentum functions of the DSBSenv auxiliary basis sets have been removed. The optimized and reduced basis sets are used in the framework of the domain-specific basis set of the incremental scheme to decrease the computation time without significant loss of accuracy. The computation times and accuracy of the previously used environmental basis and that optimized in this work have been validated with a test set of medium- to large-sized systems. The optimized and reduced DSBSenv basis sets decrease the CPU time by about 15.4% and 19.4% compared with the old environmental basis and retain the accuracy in the absolute energy with standard deviations of 0.99 and 1.06 kJ/mol, respectively