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Abstract Vapor sensors with both high sensitivity and broad detection range are technically challenging yet highly desirable for widespread chemical sensing applications in diverse environments. Generally, an increased surface‐to‐volume ratio can effectively enhance the sensitivity to low concentrations, but often with the trade‐off of a constrained sensing range. Here, an approach is demonstrated for NH₃sensor arrays with an unprecedentedly broad sensing range by introducing controllable steps on the surface of an n‐type single crystal. Step edges, serving as adsorption sites with electron‐deficient properties, are well‐defined, discrete, and electronically active. NH₃molecules selectively adsorb at the step edges and nearly eliminate known trap‐like character, which is demonstrated by surface potential imaging. Consequently, the strategy can significantly boost the sensitivity of two‐terminal NH₃resistance sensors on thin crystals with a few steps while simultaneously enhancing the tolerance on thick crystals with dense steps. Incorporation of these crystals into parallel sensor arrays results in ppb–to–% level detection range and a convenient linear relation between sheet conductance and semi‐log NH₃concentration, allowing for the precise localization of vapor leakage. In general, the results suggest new opportunities for defect engineering of organic semiconductor crystal surfaces for purposeful vapor or chemical sensing. 

Abstract Microbial strains with high genomic stability are particularly sought after for testing the quality of commercial microbiological products, such as biological media and antibiotics. Yet, using mutation–accumulation experiments and de novo assembled complete genomes based on Nanopore long-read sequencing, we find that the widely used quality-control strain Shewanella putrefaciens ATCC-8071, also a facultative pathogen, is a hypermutator, with a base-pair substitution mutation rate of 2.42 × 10−8 per nucleotide site per cell division, ∼146-fold greater than that of the wild-type strain CGMCC-1.6515. Using complementation experiments, we confirm that mutL dysfunction, which was a recent evolutionary event, is the cause for the high mutation rate of ATCC-8071. Further analyses also give insight into possible relationships between mutation and genome evolution in this important bacterium. This discovery of a well-known strain being a hypermutator necessitates screening the mutation rate of bacterial strains before any quality control or experiments. 

Rechargeable lithium–sulfur batteries have emerged as a viable technology for next generation electrochemical energy storage, and the sulfur cathode plays a critical role in determining the device performance. In this study, we prepared functional composites based on polypyrrole-coated MnO 2 nanotubes as a highly efficient sulfur host (sulfur mass loading 63.5%). The hollow interior of the MnO 2 nanotubes not only allowed for accommodation of volumetric changes of sulfur particles during the cycling process, but also confined the diffusion of lithium polysulfides by physical restriction and chemical adsorption, which minimized the loss of polysulfide species. In addition, the polypyrrole outer layer effectively enhanced the electrical conductivity of the cathode to facilitate ion and electron transport. The as-prepared MnO 2 -PPy-S composite delivered an initial specific capacity of 1469 mA h g −1 and maintained an extremely stable cycling performance, with a small capacity decay of merely 0.07% per cycle at 0.2C within 500 cycles, a high average coulombic efficiency of 95.7% and an excellent rate capability at 470 mA h g −1 at the current density of 3C. 

Abstract The discovery of photoacoustic laser streaming has opened up a new avenue to manipulate and drive fluids with light, but the necessity of an in situ “launch pad” has limited its utility in real‐world microfluidic applications due to both the size constraint and the complexity of fabrication. Here, it is demonstrated that 1) a versatile microfluidic pump can be materialized by using laser streaming from an optical fiber, and 2) laser streaming can be generated from a flat metal surface without any fabrication process. In the latter case, by focusing laser on the tip of a sewing needle tip, the needle can be turned into a micropump with controllable flow direction. Additionally, high‐speed imaging of the fluid motion and computational fluid dynamics simulations to confirm the photoacoustic principle of laser streaming are employed, and it is revealed that the streaming direction is determined by the direction of strongest intensity in the divergent ultrasound wavefront. Finally, the potential of laser streaming for microfluidic and optofluidic applications is demonstrated by successfully driving fluid inside a capillary tube.