220 research outputs found
Lorentz-Invariant Interactions in Honeycomb Lattice with Hubbard Interaction
We derive Lorentz-invariant four-fermion interactions, including
Nambu-Jona-Lasinio type (NJL) and superconducting type, which are widely
studied in high-energy physics, from the Honeycomb lattice Hamiltonian with
Hubbard interaction. We investigate the phase transitions induced by these two
interactions and consider the effects of the chemical potential and magnetic
flux (Haldane mass term) on these phase transitions. We find that the chiral
excitation and superconductivity generated by the attractive interactions are
mainly controlled by the chemical potential, while the magnetic flux delimits
the domain of phase transition. Our analysis underscores the influence of the
initial topological state on the phase transitions, a facet largely overlooked
in prior studies. We present experimental protocols using cold atoms to verify
our theoretical results
Effects of ACE inhibition on endothelial progenitor cell mobilization and prognosis after acute myocardial infarction in type 2 diabetic patients
OBJECTIVE: We aimed to assess the chemotactic response of endothelial progenitor cells to angiotensin-converting enzyme inhibitors in T2DM patients after acute myocardial infarction, as well as the associated prognosis. METHODS: Sixty-eight T2DM patients with acute myocardial infarction were randomized to either receive or not receive daily oral perindopril 4 mg, and 36 non-diabetic patients with acute myocardial infarction were enrolled as controls. The numbers of circulating CD45−/low+CD34+CD133+KDR+ endothelial progenitor cells, as well as the stromal cell-derived factor-α and high-sensitivity C reactive protein levels, were measured before acute percutaneous coronary intervention and on days 1, 3, 5, 7, 14, and 28 after percutaneous coronary intervention. Patients were followed up for 6 months. Chinese Clinical Trial Registry: ChiCTR-TRC-12002599. RESULTS: T2DM patients had lower circulating endothelial progenitor cell counts, decreased plasma vascular endothelial growth factor and α levels, and higher plasma high-sensitivity C reactive protein levels compared with non-diabetic controls. After receiving perindopril, the number of circulating endothelial progenitor cells increased from day 3 to 7, as did the plasma levels of vascular endothelial growth factor and stromal cell-derived factor-α, compared with the levels in T2DM controls. Plasma high-sensitivity C reactive protein levels in the treated group decreased to the same levels as those in non-diabetic controls. Furthermore, compared with T2DM controls, the perindopril-treated T2DM patients had lower cardiovascular mortality and occurrence of heart failure symptoms (
Tempo-Spatial Patterns of Land Use Changes and Urban Development in Globalizing China: A Study of Beijing
This study examines the temporal and spatial changes in land use as a consequence of rapid urban development in the city of Beijing. Using a combination of techniques of remote sensing and GIS, the study identifies a substantial loss of plain dryland and a phenomenal expansion of urban construction land over the recent decade. Geographically, there is a clear shifting of urban construction land from the inner city to the outskirts as a consequence of suburbanization. The outward expansion of the ring-road system is found to be one of the most important driving forces explaining the temporal and spatial pattern of land use change. The uneven distribution of population stands as another factor with significant correlation with land use change. The application of the techniques of remote sensing and GIS can enhance the precision and comparability of research on land use change and urban transformation in China
1-CycloÂpropyl-6-fluoro-7-(4-nitroÂsoÂpiperazin-1-yl)-4-oxo-1,4-dihydroÂquinoline-3-carboxylic acid
The title compound, C17H17FN4O4, is a derivative of ciprofloxacin [1-cycloÂpropyl-6-fluoro-4-oxo-7-(1-piperazinÂyl)-1,4-dihydroÂquinoline-3-carboxylic acid]. The crystal packing is stabilized by interÂmolecular C—H⋯O hydrogen bonds together with π–π electron ring interÂactions [centroid–centroid separations between quinoline rings of 3.5864 (11) and 3.9339 (13) Å]. A strong intraÂmolecular O—H⋯O hydrogen bonds is present as well as an intraÂmolecular C—H⋯F interÂaction
Guided Policy Search for Sequential Multitask Learning
Policy search in reinforcement learning (RL) is a practical approach to interact directly with environments in parameter spaces, that often deal with dilemmas of local optima and real-time sample collection. A promising algorithm, known as guided policy search (GPS), is capable of handling the challenge of training samples using trajectory-centric methods. It can also provide asymptotic local convergence guarantees. However, in its current form, the GPS algorithm cannot operate in sequential multitask learning scenarios. This is due to its batch-style training requirement, where all training samples are collectively provided at the start of the learning process. The algorithm's adaptation is thus hindered for real-time applications, where training samples or tasks can arrive randomly. In this paper, the GPS approach is reformulated, by adapting a recently proposed, lifelong-learning method, and elastic weight consolidation. Specifically, Fisher information is incorporated to impart knowledge from previously learned tasks. The proposed algorithm, termed sequential multitask learning-GPS, is able to operate in sequential multitask learning settings and ensuring continuous policy learning, without catastrophic forgetting. Pendulum and robotic manipulation experiments demonstrate the new algorithms efficacy to learn control policies for handling sequentially arriving training samples, delivering comparable performance to the traditional, and batch-based GPS algorithm. In conclusion, the proposed algorithm is posited as a new benchmark for the real-time RL and robotics research community
Application of electrochemistry to single-molecule junctions: from construction to modulation
Abstract(#br)State-of-the-art molecular electronics focus on the measurement of electrical properties of materials at the single-molecule level. Experimentally, molecular electronics face two primary challenges. One challenge is the reliable construction of single-molecule junctions, and the second challenge is the arbitrary modulation of electron transport through these junctions. Over the past decades, electrochemistry has been widely adopted to meet these challenges, leading to a wealth of novel findings. This review starts from the application of electrochemical methods to the fabrication of nanogaps, which is an essential platform for the construction of single-molecule junctions. The utilization of electrochemistry for the modification of molecular junctions, including terminal..
Association of retinopathy with risk of all-cause and specific-cause mortality in the National Health and Nutrition Examination Survey, 2005 to 2008
ObjectiveThis study aimed to elucidate the relationship between retinopathy status or severity and the all-cause and specific-cause mortality risk based on the updated National Health and Nutrition Examination Survey (NHANES) database and 2019 Public Access Link mortality file.MethodsIn this prospective cohort study, a total of 6,797 participants aged over 40 years based on NHANES 2005–2008 were analyzed. The severity of retinopathy was classified into 4 grades-no retinopathy, mild non-proliferative retinopathy (NPR), moderate to severe NPR, and proliferative retinopathy (PR). Multiple covariate-adjusted Cox proportional hazards regression models and Fine and Gray competing risk regression models were used to assess the all-cause and cause-specific mortality risks, respectively. The propensity score matching (PSM) approach was also applied additionally to adequately balance between-group covariates to validate our findings.ResultsA final total of 4,808 participants representing 18,282,772 United States (US) non-hospitalized participants were included for analysis, 50.27% were male (n = 2,417), 55.32% were non-hispanic white (n = 2,660), and mean [SE] age, 56.10 [0.40] years. After a median follow-up of 12.24 years (interquartile range, 11.16–13.49 years), 1,164 participants died of all-cause mortality, of which 941 (80.84%) died without retinopathy and 223 (19.16%) died with retinopathy at baseline. The presence of retinopathy was associated with increased all-cause mortality, cardiovascular disease (CVD), and diabetes mellitus (DM)-specific mortality, and the results remain consistent after PSM. Severity analysis showed that only mild NPR was associated with an increased all-cause mortality risk (hazard ratio (HR) = 2.01; 95% confidence interval (CI), 1.00–4.03), while increased CVD and DM-specific mortality risk were associated with all grades of retinopathy and were exponentially greater with increasing retinopathy severity, and the trend test was also significant (P for trend 0.004 and 0.04, respectively).DiscussionOur findings suggest that the diagnosis of retinopathy is an independent risk factor for all-cause mortality in people over 40 years old. Retinopathy grading is significantly associated with the survival risk of patients with CVD or DM, it can be a valuable predictor in the stratified management and risk warning of CVD or DM patients, as well as in the monitoring of systemic vasculopathy status
- …