Emulating the biological visual perception system typically requires a complex architecture including the integration of an artificial retina and optic nerves with various synaptic behaviors. ...However, self‐adaptive synaptic behaviors, which are frequently translated into visual nerves to adjust environmental light intensities, have been one of the serious challenges for the artificial visual perception system. Here, an artificial optoelectronic neuromorphic device array to emulate the light‐adaptable synaptic functions (photopic and scotopic adaptation) of the biological visual perception system is presented. By employing an artificial visual perception circuit including a metal chalcogenide photoreceptor transistor and a metal oxide synaptic transistor, the optoelectronic neuromorphic device successfully demonstrates diverse visual synaptic functions such as phototriggered short‐term plasticity, long‐term potentiation, and neural facilitation. More importantly, the environment‐adaptable perception behaviors at various levels of the light illumination are well reproduced by adjusting load transistor in the circuit, exhibiting the acts of variable dynamic ranges of biological system. This development paves a new way to fabricate an environmental‐adaptable artificial visual perception system with profound implications for the field of future neuromorphic electronics.
An optoelectronic neuromorphic device array exhibits neuromorphic behavior for mimicking the biological visual system. This device is fabricated by monolithically integrating a photovoltaic divider and ionotronic synaptic transistors with inorganic semiconductors, providing light‐adaptable artificial visual perception.
Wearable electronics are emerging as a platform for next‐generation, human‐friendly, electronic devices. A new class of devices with various functionality and amenability for the human body is ...essential. These new conceptual devices are likely to be a set of various functional devices such as displays, sensors, batteries, etc., which have quite different working conditions, on or in the human body. In these aspects, electronic textiles seem to be a highly suitable possibility, due to the unique characteristics of textiles such as being light weight and flexible and their inherent warmth and the property to conform. Therefore, e‐textiles have evolved into fiber‐based electronic apparel or body attachable types in order to foster significant industrialization of the key components with adaptable formats. Although the advances are noteworthy, their electrical performance and device features are still unsatisfactory for consumer level e‐textile systems. To solve these issues, innovative structural and material designs, and novel processing technologies have been introduced into e‐textile systems. Recently reported and significantly developed functional materials and devices are summarized, including their enhanced optoelectrical and mechanical properties. Furthermore, the remaining challenges are discussed, and effective strategies to facilitate the full realization of e‐textile systems are suggested.
Wearable electronics are emerging as a platform for next‐generation, human‐friendly, electronic devices. Consequently, a new class of devices with various functionality and amenability for the human body is essential. Here, reported and developed functional materials and devices are summarized, and the remaining challenges are discussed, suggesting effective strategies to facilitate the full realization of e‐textile systems.
A flexible and sensitive textile‐based pressure sensor is developed using highly conductive fibers coated with dielectric rubber materials. The pressure sensor exhibits superior sensitivity, very ...fast response time, and high stability, compared with previous textile‐based pressure sensors. By using a weaving method, the pressure sensor can be applied to make smart gloves and clothes that can control machines wirelessly as human–machine interfaces.
Passivation is a popular method to increase power conversion efficiency (PCE), reduce hysteresis related to surface traps and defects, and adjust mismatched energy levels. In this paper, an approach ...is reported using ammonium chloride (AC) to enhance passivation effects by controlling chlorine (Cl) and ammonium ions (NH4+) on the front and back side of tin oxides (SnO2). AC pre‐treatment is applied to indium tin‐oxide (ITO) prior to SnO2 deposition to advance the passivation approaches and compare the completely separated NH4+ and Cl passivation effects, and sole NH4+ is successfully isolated on the SnO2 surface, the counterpart of AC‐post‐treatment, generating ammonia (NH3) and Cl. It is demonstrated that multifunctional healing effects of NH4+ are ascribed from AC‐pre‐treatment being the basis of SnO2 crystallization and adjusting bifacial interface energy levels at ITO/SnO2 and SnO2/perovskite to enhance photo‐carrier transport. As calculated by density functional theory, how the change of the passivation agent from Cl to NH4+ more effectively suppresses non‐radiative recombination ascribed to hydrated SnO2 surface defects is explained. Consequently, enhancement of photo‐carrier transport significantly improves a superior open‐circuit voltage of 1.180 V and suppresses the hysteresis, which leads to the PCE of 22.25% in an AC‐pre‐treated device 3.000% higher than AC‐post‐treated devices.
Revealing the multifunctional effects of NH4+ through enhancing photo‐carrier dynamics compared to Cl, creates a self‐assembled surface trap state that causes non‐radiative recombination at the interface. The NH4+ pre‐treatment on indium tin‐oxide is an effective way to modify bifacial interfaces improving crystallinity and charge carrier transport, which leads to an increased power conversion efficiency and device stability in perovskite solar cells.
Artificial photonic synapses are emerging as a promising implementation to emulate the human visual cognitive system by consolidating a series of processes for sensing and memorizing visual ...information into one system. In particular, mimicking retinal functions such as multispectral color perception and controllable nonvolatility is important for realizing artificial visual systems. However, many studies to date have focused on monochromatic‐light‐based photonic synapses, and thus, the emulation of color discrimination capability remains an important challenge for visual intelligence. Here, an artificial multispectral color recognition system by employing heterojunction photosynaptic transistors consisting of ratio‐controllable mixed quantum dot (M‐QD) photoabsorbers and metal‐oxide semiconducting channels is proposed. The biological photoreceptor inspires M‐QD photoabsorbers with a precisely designed red (R), green (G), and blue (B)‐QD ratio, enabling full‐range visible color recognition with high photo‐to‐electric conversion efficiency. In addition, adjustable synaptic plasticity by modulating gate bias allows multiple nonvolatile‐to‐volatile memory conversion, leading to chromatic control in the artificial photonic synapse. To ensure the viability of the developed proof of concept, a 7 × 7 pixelated photonic synapse array capable of performing outstanding color image recognition based on adjustable wavelength‐dependent volatility conversion is demonstrated.
An artificial visual perception system that enables full‐range visible color recognition by employing heterojunction photosynaptic transistors consisting of precisely designed size‐mixed quantum dot photoabsorbers and amorphous In–Ga–Zn–O semiconducting channels is proposed. Moreover, this artificial photonic synapse shows chromatically controllable synaptic plasticity by gate field modulation, inducing multiple selective nonvolatile detection modes.
The combination of a neuromorphic architecture and photonic computing may open up a new era for computational systems owing to the possibility of attaining high bandwidths and the ...low‐computation‐power requirements. Here, the demonstration of photonic neuromorphic devices based on amorphous oxide semiconductors (AOSs) that mimic major synaptic functions, such as short‐term memory/long‐term memory, spike‐timing‐dependent plasticity, and neural facilitation, is reported. The synaptic functions are successfully emulated using the inherent persistent photoconductivity (PPC) characteristic of AOSs. Systematic analysis of the dynamics of photogenerated carriers for various AOSs is carried out to understand the fundamental mechanisms underlying the photoinduced carrier‐generation and relaxation behaviors, and to search for a proper channel material for photonic neuromorphic devices. It is found that the activation energy for the neutralization of ionized oxygen vacancies has a significant influence on the photocarrier‐generation and time‐variant recovery behaviors of AOSs, affecting the PPC behavior.
A brain‐inspired photonic neuromorphic device is demonstrated using an amorphous indium‐gallium‐zinc‐oxide film. By utilizing the persistent photoconductivity behavior, short‐term memory/long‐term memory, spike‐timing‐dependent plasticity, and neural facilitation are emulated, which are the important synaptic functions for learning and memory. This work may open up new possibilities to realize ultrafast and massive parallel synaptic computing systems based on photonic neuromorphic devices.
Pristine graphene quantum dots and graphene oxide quantum dots are synthesized by chemical exfoliation from the graphite nanoparticles with high uniformity in terms of shape (circle), size (less than ...4 nm), and thickness (monolayer). The origin of the blue and green photoluminescence of GQDs and GOQDs is attributed to intrinsic and extrinsic energy states, respectively.
In patients with acute myocardial infarction receiving potent antiplatelet therapy, the bleeding risk remains high during the maintenance phase. We sought data on a uniform unguided de-escalation ...strategy of dual antiplatelet therapy (DAPT) from ticagrelor to clopidogrel after acute myocardial infarction.
In this open-label, assessor-masked, multicentre, non-inferiority, randomised trial (TALOS-AMI), patients at 32 institutes in South Korea with acute myocardial infarction receiving aspirin and ticagrelor without major ischaemic or bleeding events during the first month after index percutaneous coronary intervention (PCI) were randomly assigned in a 1:1 ratio to a de-escalation (clopidogrel plus aspirin) or active control (ticagrelor plus aspirin) group. Unguided de-escalation without a loading dose of clopidogrel was adopted when switching from ticagrelor to clopidogrel. The primary endpoint was a composite of cardiovascular death, myocardial infarction, stroke, or bleeding type 2, 3, or 5 according to Bleeding Academic Research Consortium (BARC) criteria from 1 to 12 months. A non-inferiority test was done to assess the safety and efficacy of de-escalation DAPT compared with standard treatment. The hazard ratio (HR) for de-escalation versus active control group in a stratified Cox proportional hazards model was assessed for non-inferiority by means of an HR margin of 1·34, which equates to an absolute difference of 3·0% in the intention-to-treat population and, if significant, a superiority test was done subsequently. To ensure statistical robustness, additional analyses were also done in the per-protocol population. This trial is registered at ClinicalTrials.gov, NCT02018055.
From Feb 26, 2014, to Dec 31, 2018, from 2901 patients screened, 2697 patients were randomly assigned: 1349 patients to de-escalation and 1348 to active control groups. At 12 months, the primary endpoints occurred in 59 (4·6%) in the de-escalation group and 104 (8·2%) patients in the active control group (pnon-inferiority<0·001; HR 0·55 95% CI 0·40–0·76, psuperiority=0·0001). There was no significant difference in composite of cardiovascular death, myocardial infarction, or stroke between de-escalation (2·1%) and the active control group (3·1%; HR 0·69; 95% CI 0·42–1·14, p=0·15). Composite of BARC 2, 3, or 5 bleeding occurred less frequently in the de-escalation group (3·0% vs 5·6%, HR 0·52; 95% CI 0·35–0·77, p=0·0012).
In stabilised patients with acute myocardial infarction after index PCI, a uniform unguided de-escalation strategy significantly reduced the risk of net clinical events up to 12 months, mainly by reducing the bleeding events.
ChongKunDang Pharm, Medtronic, Abbott, and Boston Scientific.
Mimicking human skin sensation such as spontaneous multimodal perception and identification/discrimination of intermixed stimuli is severely hindered by the difficulty of efficient integration of ...complex cutaneous receptor‐emulating circuitry and the lack of an appropriate protocol to discern the intermixed signals. Here, a highly stretchable cross‐reactive sensor matrix is demonstrated, which can detect, classify, and discriminate various intermixed tactile and thermal stimuli using a machine‐learning approach. Particularly, the multimodal perception ability is achieved by utilizing a learning algorithm based on the bag‐of‐words (BoW) model, where, by learning and recognizing the stimulus‐dependent 2D output image patterns, the discrimination of each stimulus in various multimodal stimuli environments is possible. In addition, the single sensor device integrated in the cross‐reactive sensor matrix exhibits multimodal detection of strain, flexion, pressure, and temperature. It is hoped that his proof‐of‐concept device with machine‐learning‐based approach will provide a versatile route to simplify the electronic skin systems with reduced architecture complexity and adaptability to various environments beyond the limitation of conventional “lock and key” approaches.
A highly stretchable cross‐reactive sensor matrix for electronic‐skin applications is demonstrated, which can detect, classify, and discriminate various intermixed tactile and thermal stimuli based on machine learning. By adopting a learning algorithm based on the bag‐of‐words model, highly accurate classification of intermixed stimuli is achieved.
Abstract
All biological processes, living organisms, and ecosystems have evolved with the Sun that confers a 24-hour periodicity to life on Earth. Circadian rhythms arose from evolutionary needs to ...maximize daily organismal fitness by enabling organisms to mount anticipatory and adaptive responses to recurrent light-dark cycles and associated environmental changes. The clock is a conserved feature in nearly all forms of life, ranging from prokaryotes to virtually every cell of multicellular eukaryotes. The mammalian clock comprises transcription factors interlocked in negative feedback loops, which generate circadian expression of genes that coordinate rhythmic physiology. In this review, we highlight previous and recent studies that have advanced our understanding of the transcriptional architecture of the mammalian clock, with a specific focus on epigenetic mechanisms, transcriptomics, and 3-dimensional chromatin architecture. In addition, we discuss reciprocal ways in which the clock and metabolism regulate each other to generate metabolic rhythms. We also highlight implications of circadian biology in human health, ranging from genetic and environment disruptions of the clock to novel therapeutic opportunities for circadian medicine. Finally, we explore remaining fundamental questions and future challenges to advancing the field forward.
Graphical Abstract
Graphical Abstract
PDF