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The electrochemical CO 2 reduction reaction to produce CO is one of the most promising pathways to eliminate CO 2 emissions and store intermittent energy sources. However, the most critical usage of CO is via mixing with H 2 to form syngas, which is a crucial feedstock for many value-added chemicals. Therefore, producing syngas with a suitable CO/H 2 ratio in a one-step reaction is desirable in the CO 2 RR process. To achieve this end, dual single-atom sites supported by the nitrogen-doped carbon show great potential. Herein, we show that a dual single-atom catalyst with BiÀ N 4 and ZnÀ N 4 units is efficient for generating syngas with tunable CO/H 2 ratios (0.20 to 2.92), which is of great significance to downstream industrial production. Moreover, this work highlights the potential to control the CO/H 2 ratios for efficient syngas production using the coexisting single-atom sites.

Populus euphratica is a dominant tree in riparian ecosystems in arid areas of northwest China, but it fails to regenerate in these systems. This study evaluates causes for the failure of sexual and asexual regeneration of this species in the wild. P. euphratica disperses as many as 85743 seeds/m2 during summer, and the seeds germinate to 92.0% in distilled water and to 60.8% on silt. However, very few seeds (3.6%) can germinate on unflooded soil. The seed-rain season is prolonged by temporal variability in seed dispersal among individuals, which ensures that seedling emergence can occur during favorable conditions (i.e., floods and rainfall). As a result of water shortage and river channeling due to water usage and altered river flows, there are no safe sites on river banks for seed germination, which has led to the failure of P. euphratica to regenerate from seed. Root suckers of P. euphratica were present in 86% of the forest gaps investigated. However, extensive grazing has destroyed many of them and thus has reduced this form of regeneration. This research suggests that human activities are resulting in the failure of P. euphratica to regenerate. Changes in land management such as reduced use of concrete canals in Populus forests and/or reduced sheep grazing in these areas may promote their regeneration.

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Enterohaemorrhagic E. coli (EHEC) O157:H7 is a primary food-borne bacterial pathogen capable of causing life-threatening human infections which poses a serious challenge to public health worldwide. Intimin, the bacterial outer-membrane protein, plays a key role in the initiating process of EHEC infection. This activity is dependent upon translocation of the intimin receptor (Tir), the intimin binding partner of the bacteria-encoded host cell surface protein. Intimin has attracted considerable attention due to its potential function as an antibacterial drug target. Here, we report the crystal structure of the Tir-binding domain of intimin (Int188) from E. coli O157:H7 at 2.8 Å resolution, together with a mutant (IntN916Y) at 2.6 Å. We also built the structural model of EHEC intimin-Tir complex and analyzed the key binding residues. It suggested that the binding pattern of intimin and Tir between EHEC and Enteropathogenic E. coli (EPEC) adopt a similar mode and they can complement with each other. Detailed structural comparison indicates that there are four major points of structural variations between EHEC and EPEC intimins: one in Domain I (Ig-like domain), the other three located in Domain II (C-type lectin-like domain). These variations result in different binding affinities. These findings provide structural insight into the binding pattern of intimin to Tir and the molecular mechanism of EHEC O157: H7.