In many real-world applications, data are often collected in the form of a stream, and thus the distribution usually changes in nature, which is referred to as
concept drift
in the literature. We ...propose a novel and effective approach to handle concept drift via model reuse, that is, reusing models trained on previous data to tackle the changes. Each model is associated with a weight representing its reusability towards current data, and the weight is adaptively adjusted according to the performance of the model. We provide both generalization and regret analysis to justify the superiority of our approach. Experimental results also validate its efficacy on both synthetic and real-world datasets.
Recent progress in biosensors have quantitively expanded current capabilities in exploratory research tools, diagnostics and therapeutics. This rapid pace in sensor development has been accentuated ...by vast improvements in data analysis methods in the form of machine learning and artificial intelligence that, together, promise fantastic opportunities in chronic sensing of biosignals to enable preventative screening, automated diagnosis, and tools for personalized treatment strategies. At the same time, the importance of widely accessible personal monitoring has become evident by recent events such as the COVID-19 pandemic. Progress in fully integrated and chronic sensing solutions is therefore increasingly important. Chronic operation, however, is not truly possible with tethered approaches or bulky, battery-powered systems that require frequent user interaction. A solution for this integration challenge is offered by wireless and battery-free platforms that enable continuous collection of biosignals. This review summarizes current approaches to realize such device architectures and discusses their building blocks. Specifically, power supplies, wireless communication methods and compatible sensing modalities in the context of most prevalent implementations in target organ systems. Additionally, we highlight examples of current embodiments that quantitively expand sensing capabilities because of their use of wireless and battery-free architectures.
•Overview of building blocks for wireless and battery-free biosignal sensing platforms.•Review of wireless powering, communication and sensing approaches.•Statistical analysis of system architectures of recent published work.•Summary of current advances based on sensing target organ system.
This paper reports intrinsically stretchable thin-film transistors (TFTs) and integrated logic circuits directly printed on elastomeric polydimethylsiloxane (PDMS) substrates. The printed devices ...utilize carbon nanotubes and a type of hybrid gate dielectric comprising PDMS and barium titanate (BaTiO3) nanoparticles. The BaTiO3/PDMS composite simultaneously provides high dielectric constant, superior stretchability, low leakage, as well as good printability and compatibility with the elastomeric substrate. Both TFTs and logic circuits can be stretched beyond 50% strain along either channel length or channel width directions for thousands of cycles while showing no significant degradation in electrical performance. This work may offer an entry into more sophisticated stretchable electronic systems with monolithically integrated sensors, actuators, and displays, fabricated by scalable and low-cost methods for real life applications.
Viruses interact with hundreds to thousands of proteins in mammals, yet adaptation against viruses has only been studied in a few proteins specialized in antiviral defense. Whether adaptation to ...viruses typically involves only specialized antiviral proteins or affects a broad array of virus-interacting proteins is unknown. Here, we analyze adaptation in ~1300 virus-interacting proteins manually curated from a set of 9900 proteins conserved in all sequenced mammalian genomes. We show that viruses (i) use the more evolutionarily constrained proteins within the cellular functions they interact with and that (ii) despite this high constraint, virus-interacting proteins account for a high proportion of all protein adaptation in humans and other mammals. Adaptation is elevated in virus-interacting proteins across all functional categories, including both immune and non-immune functions. We conservatively estimate that viruses have driven close to 30% of all adaptive amino acid changes in the part of the human proteome conserved within mammals. Our results suggest that viruses are one of the most dominant drivers of evolutionary change across mammalian and human proteomes.
It is a great challenge to substantially improve the practical performance of flexible thermoelectric modules due to the absence of air-stable n-type thermoelectric materials with high-power factor. ...Here an excellent flexible n-type thermoelectric film is developed, which can be conveniently and rapidly prepared based on the as-grown carbon nanotube continuous networks with high conductivity. The optimum n-type film exhibits ultrahigh power factor of ∼1,500 μW m
K
and outstanding stability in air without encapsulation. Inspired by the findings, we design and successfully fabricate the compact-configuration flexible TE modules, which own great advantages compared with the conventional π-type configuration modules and well integrate the superior thermoelectric properties of p-type and n-type carbon nanotube films resulting in a markedly high performance. Moreover, the research results are highly scalable and also open opportunities for the large-scale production of flexible thermoelectric modules.
Twisted bilayer graphene (tBLG) exhibits a host of innovative physical phenomena owing to the formation of moiré superlattice. Especially, the discovery of superconducting behavior has generated new ...interest in graphene. The growing studies of tBLG mainly focus on its physical properties, while the fabrication of high‐quality tBLG is a prerequisite for achieving the desired properties due to the great dependence on the twist angle and the interfacial contact. Here, the cutting‐edge preparation strategies and challenges of tBLG fabrication are reviewed. The advantages and disadvantages of chemical vapor deposition, epitaxial growth on silicon carbide, stacking monolayer graphene, and folding monolayer graphene methods for the fabrication of tBLG are analyzed in detail, providing a reference for further development of preparation methods. Moreover, the characterization methods of twist angle for the tBLG are presented. Then, the unique physicochemical properties and corresponding applications of tBLG, containing correlated insulating and superconducting states, ferromagnetic state, soliton, enhanced optical absorption, tunable bandgap, and lithium intercalation and diffusion, are described. Finally, the opportunities and challenges for fabricating high‐quality and large‐area tBLG are discussed, unique physical properties are displayed, and new applications inferred from its angle‐dependent features are explored, thereby impelling the commercialization of tBLG from laboratory to market.
The progress in fabrication of twisted bilayer graphene by the mainstream methods and the topological physical properties applied in different applications is comprehensively presented. The discovery of killer applications with suitable preparation method for twisted bilayer graphene is systematically discussed by listing the advantages and disadvantages of preparation methods and various applications.
Infrared imaging systems have wide range of military or civil applications and 2D nanomaterials have recently emerged as potential sensing materials that may outperform conventional ones such as ...HgCdTe, InGaAs, and InSb. As an example, 2D black phosphorus (BP) thin film has a thickness‐dependent direct bandgap with low shot noise and noncryogenic operation for visible to mid‐infrared photodetection. In this paper, the use of a single‐pixel photodetector made with few‐layer BP thin film for near‐infrared imaging applications is demonstrated. The imaging is achieved by combining the photodetector with a digital micromirror device to encode and subsequently reconstruct the image based on compressive sensing algorithm. Stationary images of a near‐infrared laser spot (λ = 830 nm) with up to 64 × 64 pixels are captured using this single‐pixel BP camera with 2000 times of measurements, which is only half of the total number of pixels. The imaging platform demonstrated in this work circumvents the grand challenges of scalable BP material growth for photodetector array fabrication and shows the efficacy of utilizing the outstanding performance of BP photodetector for future high‐speed infrared camera applications.
A near‐infrared camera using a single black phosphorus (BP) photodetector is reported. The imaging is achieved by combining the photodetector with a digital micromirror device to encode and subsequently reconstruct the image based on a compressive sensing algorithm. Stationary images of a near‐infrared laser spot with up to 64 × 64 pixels are successfully captured using this single‐pixel BP camera.
Species of the genus
Aconitum
are widely distributed in the north temperate region and have been used in traditional medicine since antiquity due to their biological activities. Phytochemical ...investigations of
Aconitum
species have revealed the presence of multiple active ingredients, including flavonoids, phenylpropanoids, phenolics and acids, terpenoids, and polysaccharides in addition to their diterpenoid alkaloids. These non-alkaloidal constituents show great research significance for their novel structures, broad bioactivities, and chemotaxonomical significance. This review addresses, for the first time, the non-alkaloidal constituents and their biological properties and their taxonomic significance for
Aconitum
plants to facilitate future research.
Multiple non-alkaloidal constituents from
Aconitum
showed great research significance for their novel structures, broad bioactivities and chemotaxonomical significance.
To increase the commercial prospects of metal halide perovskite solar cells, there is a need for simple, cost-effective, and generalized approaches that mitigate their intrinsic thermal instability. ...Here we show that 1,3,7-trimethylxanthine, a commodity chemical with two conjugated carboxyl groups better known by its common name caffeine, improves the performance and thermal stability of perovskite solar cells based on both MAPbI3 and CsFAMAPbI3 active layers. The strong interaction between caffeine and Pb2+ ions serves as a “molecular lock” that increases the activation energy during film crystallization, delivering a perovskite film with preferred orientation, improved electronic properties, reduced ion migration, and greatly enhanced thermal stability. Planar n-i-p solar cells based on caffeine-incorporated pure MAPbI3 perovskites, which are notoriously unstable, exhibit a champion-stabilized efficiency of 19.8% and retain over 85% of their efficiency under continuous annealing at 85°C in nitrogen.
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•Caffeine enhances both thermal stability and efficiency•The stabilized power conversion efficiency of 19.8% was realized•Thermally stable solar cells at 85°C for over 1,300 h were achieved
To overcome the barrier of the commercialization of metal halide perovskite solar cells, a simple, cost-effective, and generalized strategy that mitigates the intrinsic thermal instability is strongly needed. Here, caffeine is introduced to simultaneously enhance the efficiency and thermal stability of the solar cells based on various kinds of perovskite materials. The strong interaction between caffeine and Pb2+ ions serves as a “molecular lock” that increases the activation energy during film crystallization, delivering a perovskite film with preferred orientation, improved electronic properties, reduced ion migration, and greatly enhanced thermal stability. Ultimately, a champion-stabilized efficiency of 19.8% with 1,300 h thermal stability at 85°C in nitrogen was achieved.
“Perovskite is drinking coffee.” The perfect temperature to serve coffee is 85°C. The authors here introduced caffeine, which is the active material of coffee, into the active materials of the perovskite solar cells to enhance their performance and thermal stability under 85°C. A champion-stabilized efficiency of 19.8% with 1,300 h thermal stability at 85°C in nitrogen was achieved. This simple, cost-effective, and generalized strategy increases the commercial prospects of perovskite solar cells.
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