Food and water resources are closely interconnected through economic supply chains. Existing studies have identified critical sectors as either direct water users or food consumers indirectly driving upstream water uses. However, sectors acting as intermediate transmission centres in the virtual water network driven by final food demand are overlooked. Production efficiency improvement of these critical transmission sectors (i.e., using less upstream inputs to produce unitary output) could indirectly reduce water uses of the whole supply chains. Taking China as the case, this study identifies critical transmission sectors for food-water nexus at the provincial level, based on an environmentally-extended multi-regional input-output model and the concept of betweenness. Results show that the agricultural products sectors in Shandong, Heilongjiang, and Hubei are the top three transmission sectors. They transmit 4.6, 4.1, and 3.0 billion m³ of embodied water resources, respectively. Some important transmission sectors, such as the cotton in Xinjiang and chemical industry in Jiangsu, cannot be identified by production-based and consumption-based methods. Results also highlight the necessity of strengthening inter-regional and inter-sectoral cooperation, because partial critical transmission sectors are not located in the demand provinces. Betweenness-based results can provide additional hotspots for developing sector-oriented policies for the synergistic management of food and water resources.

The identification of CN– in water, seeds, and biological systems has, because of its high toxicity, attracted the increasing attention of many chemical industry researchers. In the work, a novel highly selective and reversible sensor, MMY, was shown to recognize CN– effectively. The color and fluorescent changes verified the interaction of MMY with CN–, and the fluorescence lifetime of MMY was also changed upon addition of CN–. A mode of interaction of MMY with CN– based on the results of various experiments was speculated. The LOD of MMY toward CN– was 9.4 × 10–¹⁰ M, lower than the concentration of CN– deemed acceptable by the WHO (World Health Organization) and the U.S. EPA (United States Environmental Protection Agency). MMY showed good reversibility and reusability for detecting CN–. In addition, test slips and silica plates were both earned by ourselves, which were able to recognize CN– qualitatively. Additionally, MMY could recognize CN– in tap water quantitatively with the use of a smartphone APP. Interestingly, MMY was also used to detect CN– in seeds. It was valid to image CN– in Caenorhabditis elegans and mice with a vivid “turn-on” fluorescence. MMY thus can circulate in the bloodstream.