The production of functionalized anilines by chemoselective hydrogenation of nitroarenes occupies an important position in the chemical industries. Recently, cobalt and nitrogen codoped carbon (Co–N–C) catalysts have been reported to show outstanding catalytic performance in this process, whereas the nature of their active sites is still at the center of intense debate. In this paper, based on the well-controlled experiments on four types of typical Co–N–C materials derived from different methodologies, several unusual generalities in the hydrogenation of nitroarenes are clearly revealed, including protic-solvent dependence, antipoisoning, acid resistance, and reversible deactivation. Further investigations indicate that the single-atom species Co–N x are the main active sites of the Co–N–C catalysts in this chemoselective hydrogenation process. The present work sheds light on the mechanism study on the metal–N–C catalysts and further contributes to the rational design of the high-performance single-atom catalysts.

No abstract

EuroSCORE II could predict mortality in the entire group and in the low-middle risk group, but not in the high-risk group, in which it underestimated mortality. SinoSCORE overestimated mortality rates in the entire group and in all subgroups. Risk models should be targeted to different heart diseases, and the statistical methods of established risk systems should be improved.

dWe developed a highly sensitive reverse transcription and multiplex real-time PCR (rtPCR) assay that can identify five viruses, including six genogroups, in a single reaction: norovirus genogroups I and II; sapovirus genogroups I, II, IV, and V; human rotavirus A; adenovirus serotypes 40 and 41; and human astrovirus. In comparison to monoplex rtPCR assays, the sensitivities and specificities of the multiplex rtPCR ranged from 75% to 100% and from 99% to 100%, respectively, evaluated on 812 clinical stool specimens.

This paper presents a logic of knowledge, belief and certainty, which allows us to explicitly express the knowledge, belief and certainty of an agent. A computationally grounded model, called interpreted KBC systems, is given for interpreting this logic. The relationships between knowledge, belief and certainty are explored. In particular, certainty entails belief; and to the agent what it is certain of appears to be the knowledge. To formalize those agents that are able to introspect their own belief and certainty, we identify a subclass of interpreted KBC systems, called introspective KBC systems. We provide sound and complete axiomatizations for the logics. We show that the validity problem for the interpreted KBC systems is PSPACE-complete, and the same problem for introspective KBC systems is co-NP complete, thus no harder than that of the propositional logic.