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"Developing methods for chemical sensing is of importance in broad ap­ plications, including food safety, healthcare, and ecology. The work herein describes an approach to chemical sensing by interfacial voltage. A test electrode is coated with a dielectric and a receptor. When the test electrode contacts an electrolyte, the receptor adsorbs an analyte from the electrolyte. The adsorption generates an interfacial voltage, a measurement of which reports the concentration of the an­ alyte. This design de-integrates two aspects of sensing: adsorption and detection. Consequently, the test electrode can be made of any elec­ tronic conductor. This flexibility enables sensors to be fabricated without microelectronic facilities. Several species of ions and organic molecules are detected, and a wearable chemical sensor worn on a fingertip is demonstrated. Needle-shaped electrodes are developed to test soft biological tissues. Chemical sensing by interfacial voltage holds promise for the development of ubiquitous sensing technology." 

Significance We develop temperature sensors on the basis of charges accumulated at the electrolyte/dielectric interface and dielectric/electrode interface. The accumulated charges make the temperature sensors self-powered, which simplifies circuit design and enables portable sensing. The sensors are stretchable, but deformation does not affect temperature sensing. The sensors have high sensitivity and fast response. They can be made small and transparent. Such temperature sensors open new possibilities to create human–machine interfaces and soft robots in healthcare and engineering. 

ABSTRACT Cropland redistribution to marginal land has been reported worldwide; however, the resulting impacts on environmental sustainability have not been investigated sufficiently. Here we investigated the environmental impacts of cropland redistribution in China. As a result of urbanization-induced loss of high-quality croplands in south China (∼8.5 t ha–1), croplands expanded to marginal lands in northeast (∼4.5 t ha–1) and northwest China (∼2.9 t ha–1) during 1990–2015 to pursue food security. However, the reclamation in these low-yield and ecologically vulnerable zones considerably undermined local environmental sustainability, for example increasing wind erosion (+3.47%), irrigation water consumption (+34.42%), fertilizer use (+20.02%) and decreasing natural habitats (−3.11%). Forecasts show that further reclamation in marginal lands per current policies would exacerbate environmental costs by 2050. The future cropland security risk will be remarkably intensified because of the conflict between food production and environmental sustainability. Our research suggests that globally emerging reclamation of marginal lands should be restricted and crop yield boost should be encouraged for both food security and environmental benefits.