Atomically dispersed metal‐nitrogen sites show great prospect for the oxygen reduction reaction (ORR), whereas the unsatisfactory adsorption‐desorption behaviors of oxygenated intermediates on the metal centers impede improvement of the ORR performance. We propose a new conceptual strategy of introducing sacrificial bonds to remold the local coordination of Fe−Nx sites, via controlling the dynamic transformation of the Fe−S bonds in the Fe−N−C single‐atom catalyst. Spectroscopic and theoretical results reveal that the selective cleavage of the sacrificial Fe−S bonds induces the incorporation of the electron‐withdrawing oxidized sulfur on the Fe centers. The newly functionalized moieties endow the catalyst with superior ORR activity and remarkable stability, owing to the reduced electron localization around the Fe centers facilitating the desorption of ORR intermediates. These findings provide a unique perspective for precisely controlling the coordination structure of single‐atom materials to optimize their activity.
China has over the last two decades been committed to creating a strategic partnership with Latin American states by persistently extending its economic and political involvement in the continent. China's efforts in this regard reflect not only its desire to intensify its economic cooperation and political relations with nations in Latin America, but also its strategic goals of creating its own sphere of influence in the region and enhancing its ‘hard’ and ‘soft’ power in order to elevate China's status at the systemic level. With access to Latin American markets, resources and investment destinations, China may sustain its economic and social progress that bases its long cherished dream of restoring its past glory of fuqiang (wealth and power) and rise as a global power capable of reshaping the current world system. The enormous economic benefits deriving from their economic cooperation and trade may persuade Latin American nations to accept the basic premise of China's economic strategy: that China's rise is not a threat, but an opportunity to gain wealth and prosperity. This will help China gain more ‘soft’ power in and leverage over its economic partners in Latin America, and thereby help it to rise in the global power hierarchy.
A palladium-catalyzed intramolecular isoindolinone-forming aminooxygenation of alkenes with 1 atm of oxygen as oxidant is reported. A variety of functionalized alkenes and carboxylic acids can be used, and high yields were observed. Preliminary mechanistic studies revealed that the aminooxygenation products were formed through the oxidation of a C-Pd(II) species using a strong oxidant, peroxide, which is generated in situ from a Pd(OAc)2/bpy/O2/HOAc catalytic system.
In this paper, we study the local exact boundary controllability of entropy solutions to a class linearly degenerate hyperbolic systems of conservation laws with constant multiplicity. The authors prove the two-sided boundary controllability, one-sided boundary controllability and two-sided controllability with less controls, by applying the strategy used in [9] originally for classical solutions with essential modifications. Our constructive method is based on the well-posedness of semi-global solutions constructed by the limit of ε-approximate front tracking solutions to the mixed initial-boundary value problem with general nonlinear boundary conditions and some further properties on both ε-approximate front tracking solutions and entropy solutions, which are obtained in [10] and [12].
This paper proposes an alternative perspective on service quality management (SQM) based on the ecosystem of complex and dynamic service environments. First, the ways in which systems thinking and core principles of Quality Management evolved are analysed in order to understand the past, present and the future. Then, by analysing the theories, models and applications of SQM systems and business ecosystems, the paper proposes a framework model for a service ecosystem. The proposed service ecosystem is based on value co-creation that can be utilised to manage service quality and to increase innovability. Through two case studies, the differences between the traditional approach to SQM and the application of ecosystem theory to SQM are compared and reflected. The case studies indicate that ecosystem theory can be used to manage service quality and to achieve success in value co-creation through new innovative practices.
In the past eight years, Chinese main newspapers have significantly increased the number of cancer-related reports and paid more attention to women's cancers.
Background: Acquired dysphagia is common in patients with tracheal intubation and neurological disease, leading to increased mortality. This study aimed to ascertain the risk factors and develop a prediction model for acquired dysphagia in patients after neurosurgery.Methods: A multicenter prospective observational study was performed on 293 patients who underwent neurosurgery. A standardized swallowing assessment was performed bedside within 24 h of extubation, and logistic regression analysis with a best subset selection strategy was performed to select predictors. A nomogram model was then established and verified.Results: The incidence of acquired dysphagia in our study was 23.2% (68/293). Among the variables, days of neurointensive care unit (NICU) stay [odds ratio (OR), 1.433; 95% confidence interval (CI), 1.141–1.882; P = 0.005], tracheal intubation duration (OR, 1.021; CI, 1.001–1.062; P = 0.175), use of a nasogastric feeding tube (OR, 9.131; CI, 1.364–62.289; P = 0.021), and Acute Physiology and Chronic Health Evaluation (APACHE)-II C score (OR, 1.709; CI, 1.421–2.148; P < 0.001) were selected as risk predictors for dysphagia and included in the nomogram model. The area under the receiver operating characteristic curve was 0.980 (CI, 0.965–0.996) in the training set and 0.971 (0.937–1) in the validation set, with Brier scores of 0.045 and 0.056, respectively.Conclusion: Patients who stay longer in the NICU, have a longer duration of tracheal intubation, require a nasogastric feeding tube, and have higher APACHE-II C scores after neurosurgery are likely to develop dysphagia. This developed model is a convenient and efficient tool for predicting the development of dysphagia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.