Development of a Transferable Reactive Force Field of P/H Systems: Application to the Chemical and Mechanical Properties of Phosphorene

ReaxFF provides a method to model reactive chemical systems in large-scale molecular dynamics simulations. Here, we developed ReaxFF parameters for phosphorus and hydrogen to give a good description of the chemical and mechanical properties of pristine and defected black phosphorene. ReaxFF for P/H is transferable to a wide range of phosphorus and hydrogen containing systems including bulk black phosphorus, blue phosphorene, edge-hydrogenated phosphorene, phosphorus clusters and phosphorus hydride molecules. The potential parameters were obtained by conducting unbiased global optimization with respect to a set of reference data generated by extensive ab initio calculations. We extend ReaxFF by adding a 60{\deg} correction term which significantly improves the description of phosphorus clusters. Emphasis has been put on obtaining a good description of mechanical response of black phosphorene with different types of defects. Compared to nonreactive SW potential [1], ReaxFF for P/H systems provides a huge improvement in describing the mechanical properties the pristine and defected black phosphorene and the thermal stability of phosphorene nanotubes. A counterintuitive phenomenon is observed that single vacancies weaken the black phosphorene more than double vacancies with higher formation energy. Our results also show that mechanical response of black phosphorene is more sensitive to defects for the zigzag direction than for the armchair direction. Since ReaxFF allows straightforward extensions to the heterogeneous systems, such as oxides, nitrides, ReaxFF parameters for P/H systems build a solid foundation for the reactive force field description of heterogeneous P systems, including P-containing 2D van der Waals heterostructures, oxides, etc

Increased circulating obestatin in patients with chronic obstructive pulmonary disease

BACKGROUND: Some peptides, which regulate the metabolic balance, are thought to play important roles in nutritional disorders and systemic inflammation in COPD. Treatment of rats with obestatin decreased body-weight gain. Obestatin was also found to be correlated with inflammation in rheumatoid arthritis. The aims of this study were to investigate the level of circulating obestatin in COPD and to analyze the relationship among obestatin and nutritional status, and systemic inflammation. METHODS: 32 COPD patients with BMI less than 20 kg/m(2) and 22 normal controls were included. Body composition was estimated using “foot-to-foot” BIA technology. Circulating obestatin was determined with enzyme-linked immunosorbent assay. Pulmonary function, TNF-α and C reactive protein were also measured. RESULTS: The level of circulating obestatin was higher in COPD with underweight than that in normal control (5562.75 ± 3435.43 pg/ml in COPD, 3663.90 ± 2313.95 pg/ml in controls, p = 0.028). BMI, Waist circumference, hip circumference, bodyFAT and FAT% in COPD group were lower than those in normal control. Positive correlation was found among circulating C reactive protein, TNF-α and obestatin. There was no significant correlation among BMI, pulmonary function and obestatin. CONCLUSIONS: This study shows that circulating obestatin is higher in underweight COPD patients, and positively correlated to systemic inflammation, but not to nutritional status

Association between cognitive impairment and risk of atrial fibrillation: The Atherosclerosis Risk in Communities study

Background: Atrial fibrillation (AF) is reportedly a risk factor for cognitive impairment. Interestingly, recent studies have emphasized that impaired cognition is probably an initiating factor of cardiovascular disease. Thus, we aimed to explore the association between impaired cognition and the risk of AF, and clarify the potential mechanisms. Methods: Participants of visit 2 (1991–1993) in the Atherosclerosis Risk in Communities study were included. Global cognition z-scores and factor scores were calculated using the word fluency, delayed word recall, and digit symbol substitution tests. AF incidents were diagnosed by electrocardiography and inpatient records. The association of cognitive decline with AF risk and left atrial volume index (LAVI) was explored using Cox proportional hazards and linear regression models, respectively. Results: During the median follow-up of 18.2 ± 6.2 years, 2056/11,675 (17.6%) participants developed AF. Participants in the lowest quartile of global cognition z- and factor scores had a higher risk of AF (hazard ratio [HR]: 1.271, 95% confidence interval [CI]: 1.094–1.477, p = 0.002; HR: 1.305, 95% CI: 1.110–1.535, p = 0.001, respectively) than those in the highest quartile. Global cognition z- and factor scores were negatively correlated with the LAVI (B: –0.411, 95% CI: –0.749 to –0.074, p = 0.017; B: –0.425, 95% CI: –0.833 to –0.017, p = 0.041, respectively). Conclusions: Cognitive decline is significantly associated with a higher risk of AF, with atrial remodeling being a potential mechanism. Our results extend previous findings of the brain-heart axis and indicate the effects of cognitive injury on cardiac function and structure. Registration: URL: https://www.clinicaltrials.gov; unique identifier: NCT0000513

KwaiYiiMath: Technical Report

Recent advancements in large language models (LLMs) have demonstrated remarkable abilities in handling a variety of natural language processing (NLP) downstream tasks, even on mathematical tasks requiring multi-step reasoning. In this report, we introduce the KwaiYiiMath which enhances the mathematical reasoning abilities of KwaiYiiBase1, by applying Supervised Fine-Tuning (SFT) and Reinforced Learning from Human Feedback (RLHF), including on both English and Chinese mathematical tasks. Meanwhile, we also constructed a small-scale Chinese primary school mathematics test set (named KMath), consisting of 188 examples to evaluate the correctness of the problem-solving process generated by the models. Empirical studies demonstrate that KwaiYiiMath can achieve state-of-the-art (SOTA) performance on GSM8k, CMath, and KMath compared with the similar size models, respectively.Comment: technical report. arXiv admin note: text overlap with arXiv:2306.16636 by other author