Inhibited oxidase mimetic activity of palladium nanoplates by poisoning the active sites for thiocyanate detection.

In this work, a novel convenient colorimetric method for sensitive detection of thiocyanate (SCN-) has been developed based on its suppression of the oxidase-like activity of palladium square nanoplates on reduced graphene oxide (Pd SP@rGO). SCN- can be adsorbed onto the surface of Pd SP@rGO via binding with Pd atoms and blocks the active sites that mimic oxidase, thus inhibiting the corresponding chromogenic reaction of 3,3',5,5'-tetramethylbenzidine, which has been comprehensively revealed by the UV-vis spectra and X-ray photoelectron spectra. The color fading exhibits SCN- concentration-dependent behavior and can be easily recorded by either UV-vis spectroscopy or naked-eye observation. Therefore, both quantitative detection via measurement of the decrease in absorbance and visual detection of SCN- can be achieved. Owing to the intrinsic amplification of signals by the oxidase-like activity of Pd SP@rGO without resorting to unstable and destructive H2O2, this assay is straightforward, robust and sensitive enough for the detection of SCN- in real samples. Furthermore, an "INH" logic gate is rationally constructed based on the proposed colorimetric SCN- sensor.

Environmental governance in China: Interactions between the state and "nonstate actors".

In the West, limited government capacity to solve environmental problems has triggered the rise of a variety of "nonstate actors" to supplement government efforts or provide alternative mechanisms for addressing environmental issues. How does this development - along with our efforts to understand it - map onto environmental governance processes in China? China's efforts to address environmental issues reflect institutionalized governance processes that differ from parallel western processes in ways that have major consequences for domestic environmental governance practices and the governance of China "going abroad." China's governance processes blur the distinction between the state and other actors; the "shadow of the state" is a major factor in all efforts to address environmental issues. The space occupied by nonstate actors in western systems is occupied by shiye danwei ("public service units"), she hui tuanti ("social associations") and e-platforms, all of which have close links to the state. Meanwhile, international NGOs and multinational corporations are also significant players in China. As a result, the mechanisms of influence that produce effects in China differ in important ways from mechanisms familiar from the western experience. This conclusion has far-reaching implications for those seeking to address global environmental concerns, given the importance of China's growing economy and burgeoning network of trade relationships.

Prudently conduct the engineering and synthesis of the SARS-CoV-2 virus.

In response to the outbreak of COVID-19 that has been sweeping the world, scientists reconstructed the SARS-CoV-2 rapidly using a synthetic genomics platform, in order to accelerate therapeutics and vaccine development. However, given the dual-use nature of this technology, there exists a high biosecurity risk. This paper points out the potential risks of the engineering SARS-CoV-2 virus and puts forward 6 questions to this work. The authors emphasize that the two basic values of safety/security and intellectual freedom of research must be considered evenly. From the perspective of responsible development of biotechnology, this paper calls for a careful assessment to the risks of the technology, replacing risky technologies with safe ones. The risks of publication also need to be strictly assessed. The authors believe, in addition to enhancing the "self-government" and self-discipline of scientists and scientific communities, government supervision must be reinforced, laws and regulations should be improved, and global regulation framework ought to be constructed.