GradDFT. A software library for machine learning enhanced density functional theory.

Density functional theory (DFT) stands as a cornerstone method in computational quantum chemistry and materials science due to its remarkable versatility and scalability. Yet, it suffers from limitations in accuracy, particularly when dealing with strongly correlated systems. To address these shortcomings, recent work has begun to explore how machine learning can expand the capabilities of DFT: an endeavor with many open questions and technical challenges. In this work, we present GradDFT a fully differentiable JAX-based DFT library, enabling quick prototyping and experimentation with machine learning-enhanced exchange-correlation energy functionals. GradDFT employs a pioneering parametrization of exchange-correlation functionals constructed using a weighted sum of energy densities, where the weights are determined using neural networks. Moreover, GradDFT encompasses a comprehensive suite of auxiliary functions, notably featuring a just-in-time compilable and fully differentiable self-consistent iterative procedure. To support training and benchmarking efforts, we additionally compile a curated dataset of experimental dissociation energies of dimers, half of which contain transition metal atoms characterized by strong electronic correlations. The software library is tested against experimental results to study the generalization capabilities of a neural functional across potential energy surfaces and atomic species, as well as the effect of training data noise on the resulting model accuracy.

Association between axial length and level of education in elderly patients with cataracts unexposed to electronic devices in the first two decades of life / Associação entre diâmetro axial e nível educacional em pacientes idosos com catarata não expostos a dispositivos eletrônicos nas duas primeiras décadas de vida

ABSTRACT Purpose: To determine whether the axial length is associated with the education level in elderly patients with cataracts who were not exposed to electronic devices in the first two decades of life. Methods: This cross-sectional study was conducted in elderly patients with cataracts in Campinas, Brazil. Patients were divided into 2 groups: Group 1 included those who completed, at most, elementary school (including the illiterate and those who partially or totally attended elementary school), which corresponded to 12 years of schooling; Group 2 included, at least, high school graduates (including those who completed high school and those who partially or fully attended university). The sample was selected randomly with stratification for sex and age. The main outcome was the axial length. Results: The sample consisted of 472 elderly patients (236 per group) who underwent cataract surgery. There were 272 (57.6%) men and 200 (42.4%) women; the distribution was symmetrical between the two groups. The median age (IQR; range) was 66 (12; 50-89) years. The median axial length (IQR; range) was 22.82 (1.51; 20.34-28.71) mm in Group 1 and 23.32 (1.45; 20.51-31.34) mm in Group 2 (p<0.001). Conclusion: A greater axial length was associated with a higher level of education in elderly patients with cataracts, suggesting that myopization is related to an increase in activities requiring near-vision even before exposure to electronic devices.

RESUMO Objetivo: Determinar se o diâmetro axial está asso­ciado ao nível educacional em pacientes idosos com catarata que não foram expostos a dispositivos eletrônicos nas duas primeiras décadas de vida. Métodos: Este estudo transversal foi conduzido em pacientes idosos com catarata na cidade de Campinas, Brasil. Os Pacientes foram divididos em 2 grupos: no Grupo 1 foram incluídos aqueles que completaram, pelo menos, o ensino fundamental (incluindo analfabetos e aqueles com ensino fundamental completo ou incompleto), o que corresponde a 12 anos de escolaridade; no Grupo 2 foram incluídos indivíduos que, pelo menos, estudaram até o ensino médio (incluindo indivíduos com ensino médio completo e superior completo ou superior incompleto). A amostra foi selecionada aleatoriamente com estratificação por sexo e idade. O desfecho principal foi a medida do diâmetro axial. Resultados: A amostra foi constituída por 472 indivíduos que foram submetidos a cirurgia de catarata. Duzentos e trinta e seis indivíduos (50%) foram alocados no Grupo 1 e duzentos e trinta e seis indivíduos (50%) no Grupo 2. A mediana da idade (IIQ; intervalo) foi 66 (12; 50-89) anos. Duzentos e setenta e dois (57,6%) eram homens e duzentos (42,4%) mulheres, com distribuição simétrica entre os dois grupos. A mediana do diâmetro axial (IIQ; intervalo) foi 22,82 (1,51; 20,34-28,71) mm no Grupo 1 e 23,32 (1,45; 20,51-31,34) mm no Grupo 2 (p<0,001). Conclusão: Maiores medidas de diâmetro axial foram asso­ciadas a níveis educacionais mais elevados em pacientes idosos submetidos a cirurgia de catarata. Tal achado sugere que a miopização relacionada ao aumento de atividades que utilizam a visão de perto é fenômeno que ocorre antes mesmo da exposição a dispositivos eletrônicos.

Developing a Chemical and Structural Understanding of the Surface Oxide in a Niobium Superconducting Qubit.

Superconducting thin films of niobium have been extensively employed in transmon qubit architectures. Although these architectures have demonstrated improvements in recent years, further improvements in performance through materials engineering will aid in large-scale deployment. Here, we use information retrieved from secondary ion mass spectrometry and electron microscopy to conduct a detailed assessment of the surface oxide that forms in ambient conditions for transmon test qubit devices patterned from a niobium film. We observe that this oxide exhibits a varying stoichiometry with NbO and NbO2 found closer to the niobium film/oxide interface and Nb2O5 found closer to the surface. In terms of structural analysis, we find that the Nb2O5 region is semicrystalline in nature and exhibits randomly oriented grains on the order of 1-3 nm corresponding to monoclinic N-Nb2O5 that are dispersed throughout an amorphous matrix. Using fluctuation electron microscopy, we are able to map the relative crystallinity in the Nb2O5 region with nanometer spatial resolution. Through this correlative method, we observe that the highly disordered regions are more likely to contain oxygen vacancies and exhibit weaker bonds between the niobium and oxygen atoms. Based on these findings, we expect that oxygen vacancies likely serve as a decoherence mechanism in quantum systems.

Association between axial length and level of education in elderly patients with cataracts unexposed to electronic devices in the first two decades of life.

PURPOSE: To determine whether the axial length is associated with the education level in elderly patients with cataracts who were not exposed to electronic devices in the first two decades of life. METHODS: This cross-sectional study was conducted in elderly patients with cataracts in Campinas, Brazil. Patients were divided into 2 groups: Group 1 included those who completed, at most, elementary school (including the illiterate and those who partially or totally attended elementary school), which corresponded to 12 years of schooling; Group 2 included, at least, high school graduates (including those who completed high school and those who partially or fully attended university). The sample was selected randomly with stratification for sex and age. The main outcome was the axial length. RESULTS: The sample consisted of 472 elderly patients (236 per group) who underwent cataract surgery. There were 272 (57.6%) men and 200 (42.4%) women; the distribution was symmetrical between the two groups. The median age (IQR; range) was 66 (12; 50-89) years. The median axial length (IQR; range) was 22.82 (1.51; 20.34-28.71) mm in Group 1 and 23.32 (1.45; 20.51-31.34) mm in Group 2 (p<0.001). CONCLUSION: A greater axial length was associated with a higher level of education in elderly patients with cataracts, suggesting that myopization is related to an increase in activities requiring near-vision even before exposure to electronic devices.

Spatial Mapping of Electrostatic Fields in 2D Heterostructures.

In situ electron microscopy is an effective tool for understanding the mechanisms driving novel phenomena in 2D structures. However, due to practical challenges, it is difficult to address these technologically relevant 2D heterostructures with electron microscopy. Here, we use the differential phase contrast (DPC) imaging technique to build a methodology for probing local electrostatic fields during electrical operation with nanoscale spatial resolution in such materials. We find that, by combining a traditional DPC setup with a high-pass filter, we can largely eliminate electric fluctuations emanating from short-range atomic potentials. Using a method based on this filtering algorithm, a priori electric field expectations can be directly compared with experimentally derived values to readily identify inhomogeneities and potentially problematic regions. We use this platform to analyze the electric field and charge density distribution across layers of hBN and MoS2.

Degeneration Behavior of Cu Nanowires under Carbon Dioxide Environment: An In Situ/Operando Study.

Copper (Cu) is a catalyst broadly used in industry for hydrogenation of carbon dioxide, which has broad implications for environmental sustainability. An accurate understanding of the degeneration behavior of Cu catalysts under operando conditions is critical for uncovering the failure mechanism of catalysts and designing novel ones with optimized performance. Despite the widespread use of these materials, their failure mechanisms are not well understood because conventional characterization techniques lack the necessary time and spatial resolution to capture these complex behaviors. In order to overcome these challenges, we carried out transmission electron microscopy (TEM) with a specialized in situ gas environmental holder, which allows us to unravel the dynamic behavior of the Cu nanowires (NWs) in operando. The failure process of these nanoscale Cu catalysts under CO2 atmosphere were tracked and further rationalized based on our numerical modeling using phase-field methods.

To What Extent Do Physician Orders for Life-Sustaining Treatment (POLST) Reflect Patients' Preferences for Care at the End of Life?

OBJECTIVE: To assess whether medical orders within Physician Orders for Life-Sustaining Treatment (POLST) forms reflect patients' preferences for care at the end of life. DESIGN: This cross-sectional study assessed the agreement between medical orders in POLST forms and the free-form text documentation of an advance care planning conversation performed by an independent researcher during a single episode of hospitalization. SETTING AND PARTICIPANTS: Inpatients at a single public university hospital, aged 21 years or older, and for whom one of their attending physicians provided a negative answer to the following question: "Would I be surprised if this patient died in the next year?" Data collection occurred between October 2016 and September 2017. MEASURES: Agreement between medical orders in POLST forms and the free-form text documentation of an advance care planning conversation was measured by kappa statistics. RESULTS: Sixty-two patients were interviewed. Patients' median (interquartile range) age was 62 (56-70) years, and 21 patients (34%) were women. Overall, in 7 (11%) cases, disagreement in at least 1 medical order for life-sustaining treatment was found between POLST forms and the content of the independent advance care planning conversation. The kappa statistic for cardiopulmonary resuscitation was 0.92 [95% confidence interval (CI): 0.82-1.00]; for level of medical intervention, 0.90 (95% CI: 0.81-0.99); and for artificially administered nutrition, 0.87 (95% CI: 0.75-0.98). CONCLUSIONS AND IMPLICATIONS: The high level of agreement between medical orders in POLST forms and the documentation in an independent advance care planning conversation offers further support for the POLST paradigm. In addition, the finding that the agreement was not 100% underscores the need to confirm frequently that POLST medical orders accurately reflect patients' current values and preferences of care.

Safety and efficacy of intracameral moxifloxacin for prevention of post-cataract endophthalmitis: Randomized controlled clinical trial.

PURPOSE: To evaluate the safety and efficacy of intracameral (IC) 0.5% moxifloxacin in the prevention of post-cataract endophthalmitis. SETTING: University of Campinas, São Paulo, Brazil. DESIGN: Prospective randomized partially masked single-site clinical trial. METHODS: Patients who had phacoemulsification were randomized into two groups in block sizes of 4. Group A (moxifloxacin group) consisted of patients who received an IC injection of 0.03 mL (150 µg) of undiluted 0.5% moxifloxacin at the end of surgery. Group B (control group) consisted of patients who received no IC medication. The postoperative prescription for both groups consisted of 0.5% moxifloxacin and 0.1% dexamethasone. Patients were monitored for 6 weeks after surgery. The primary outcome was the incidence of acute endophthalmitis in each group. Secondary outcomes were corrected distance visual acuity (CDVA), endothelial cell density (ECD), intraocular pressure (IOP), and central corneal thickness (CCT). RESULTS: The study comprised 3640 eyes from 3640 patients. There were 1818 patients in Group A and 1822 patients in Group B. The incidence of endophthalmitis within 6 weeks of follow-up was 1 (0.05%) of 1818 eyes in the moxifloxacin group and 7 (0.38%) of 1822 eyes in the control group (P = .035). There was no significant difference in CDVA (P = .202), ECD (P = .482), IOP (P = .105), or CCT (P = .558). No ocular or systemic study-related adverse events were observed. CONCLUSIONS: The IC injection of undiluted 0.5% moxifloxacin can be safely applied as the last step of phacoemulsification. It was found to be effective in reducing the risk for endophthalmitis. This study represents the first controlled randomized clinical trial to evaluate the safety and efficacy of IC moxifloxacin in the prevention of post-cataract endophthalmitis.