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Studying two-dimensional (2D) materials using transmission electron microscopy (TEM) is necessary and very important in many aspects. However, some 2D materials are not resistant to acids or alkalis, which are widely used in normal wet transfer techniques to transfer the exfoliated 2D nanosheets onto the TEM grids. On the other hand, dry stamping method can damage the holey carbon film on the TEM grids. In this article, we present a non-destructive, efficient, and widely applicable transfer method for preparing the TEM samples of the exfoliated 2D materials. Our method only uses the heat-release tape, PMMA, and blue Nitto tape. Neither acid nor alkali is involved in our method, therefore, impurities and damage can be avoided to the greatest extent. The method is also very efficient and can be accomplished in less than 30 min after the exfoliation of the 2D materials. This method is particularly useful for preparing the TEM samples of the 2D materials that are not resistant to acids and alkalis. The present method is also applicable to various 2D materials and various substrates. [ABSTRACT FROM AUTHOR]

α-In2Se3 has attracted increasing attention in recent years due to its excellent electrical and optical properties. Especially, attention has been paid to its peculiar ferroelectric and piezoelectric properties which most other two-dimensional (2D) materials do not possess. This paper presents the first measurement of the thickness-dependent band gaps of few-layer α-In2Se3 by electron energy loss spectroscopy (EELS). The band gap increases with decreasing film thickness which varies from 1.44 eV in a 48 nm thick area to 1.64 eV in an 8 nm thick area of the samples. Further, by combining the improved exchange-correlation potential and proper screening of the internal electric field in an advanced 2D electronic structure technique, we have been able to obtain the structural dependence of the band gap within density functional theory up to hundreds of atoms. This is also the first calculation of a similar type for 2D ferroelectric materials. Both experiment and theory suggest that the variation of the band gap of α-In2Se3 fits well with the quantum confinement model for 2D materials. [ABSTRACT FROM AUTHOR]

Antibiotic resistance has emerged as an imminent threat to public health. It is also increasingly recognized to be a heterogeneous phenomenon: a population of bacteria, found in vivo or in vitro , often consists of a mixture of cells that have different degrees of resistance to antibiotics. The conventional metric to measure antibiotic resistance based on an ensemble-average minimum inhibitory concentration (MIC) fails to characterize the heterogeneity present within a bacterial population. This work describes a droplet microfluidics method to encapsulate single cells from a population consisting of a mixture of antibiotic-sensitive and antibiotic-resistant bacteria. Co-encapsulating viability probe alamarBlue with the cells allows the use of fluorescent drops as a read-out for drops that contain live cells after their exposure to antibiotics. Enumerating the fluorescent drops thus gives the number of resistant cells in the population. Our method enables the quantitative phenotyping of heterogeneous resistance, or heteroresistance, with single-cell resolution. We show that it is possible to detect a resistant sub-population that comprises as low as 10 −6 of the entire population of cells. Such high resolution further allows us to measure the evolution of heteroresistance arising from the exposure of a homogeneous isogenic culture of susceptible cells to sub-lethal dosages of antibiotics. We demonstrate an application of this system to characterize genetic determinants of antimicrobial resistance emergence. The high resolution of phenotypic detection and quantification of minority variants demonstrated in this work has the potential to facilitate the elucidation of the mechanisms underlying heteroresistance. Such understanding will in turn inform the best practices for antibiotic use and containment of antimicrobial resistance in a wide range of settings from agriculture and aquaculture to disease management. Clinically, the ability to quantify and track the composition of a bacterial population will benefit the decision-making process in both the diagnosis and the treatment of bacterial infections, and will ultimately improve patient outcome and avert the spread of resistant populations. [ABSTRACT FROM AUTHOR]

Protein molecules were directly embeddedin metal–organicframeworks (MOFs) by a coprecipitation method. The protein moleculesmajorly embedded on the surface region of MOFs display high biologicalactivities. As a demonstration of the power of such materials, theresulting Cyt cembedded in ZIF-8 showed a 10-foldincrease in peroxidase activity compared to free Cyt cin solution and thus gave convenient, fast, and highly sensitivedetection of trace amounts of explosive organic peroxides in solution. [ABSTRACT FROM AUTHOR]

2D layered semiconductors with excellent light−matter interaction and atomic‐scale thickness have been envisioned as promising candidates for more than Moore and beyond Moore technologies. Here, for the first time, a multi‐functional platform is reported that is fabricated entirely from wrinkle‐free 2D ferroelectric semiconductor α‐In2Se3 integrated with a photodetector, reconfigurable logic switching, and visual perception processing functions. The intensity‐ and wavelength‐dependent resistance is used to demodulate broadband optical information into electrical signals and perform reconfigurable logic switching. Moreover, the platform offers dynamically modulated photosensitive visual sensing in different working modes at the pixel level. Using photo‐assisted piezoresponse force microscopy, the optical‐engineered ferroelectric polarization switch behavior is explored. The platform has excellent sensitivity to both optical and electrical stimuli and can respond to lights in the visible to short‐wavelength infrared region in volatile/non‐volatile manner under gate voltage modulation, with a response of 98 mA W−1 (to 1800 nm light), a current on/off ratio of over 106, and a high field‐effect mobility of 137.55 cm2 V−1 s−1. With its simple structure, unique photoelectric interaction, and controllable operating mechanism, the platform has the potential to simplify the complexity of neuromorphic computing circuitry systems, paving the way for high‐performance hybrid technologies suitable for artificial intelligence applications. [ABSTRACT FROM AUTHOR]