The challenges of developing neuromorphic vision systems inspired by the human eye come not only from how to recreate the flexibility, sophistication, and adaptability of animal systems, but also how ...to do so with computational efficiency and elegance. Similar to biological systems, these neuromorphic circuits integrate functions of image sensing, memory and processing into the device, and process continuous analog brightness signal in real-time. High-integration, flexibility and ultra-sensitivity are essential for practical artificial vision systems that attempt to emulate biological processing. Here, we present a flexible optoelectronic sensor array of 1024 pixels using a combination of carbon nanotubes and perovskite quantum dots as active materials for an efficient neuromorphic vision system. The device has an extraordinary sensitivity to light with a responsivity of 5.1 × 10
A/W and a specific detectivity of 2 × 10
Jones, and demonstrates neuromorphic reinforcement learning by training the sensor array with a weak light pulse of 1 μW/cm
.
•Structure-property relation of oxidized sodium alginate (OSA) was investigated.•Molecular weight of OSA is a key factor in improving properties of collagen fiber.•Effect of aldehyde group content ...was less obvious than that of molecular weight.
A series of periodate oxidized sodium alginate (OSA) were prepared as green polysaccharide-based crosslinkers. The molecular weight of OSA decreased, while their aldehyde group content increased with increasing dosage of sodium periodate. A typical OSA was further fractionated to four fractions by ethanol with a narrower molecular weight distribution. Then the crosslinking performances of OSAs/fractions on collagen fiber (CF) were investigated. DSC and SEM analyses showed that the thermal stability and dispersion degree of crosslinked CF was considerably enhanced with decreasing molecular weight of OSA. The effect of aldehyde group content of OSA on its crosslinking performance was less obvious than that of molecular weight, probably because the aldehyde group content in each OSA sample was higher than the amino group content of CF involved in the crosslinking reaction. In general, molecular weight of OSA plays a decisive role in improving properties of the crosslinked CF.
A bithiophene−alkyne‐based compound was synthesized and first utilized as a ligand for the selective hydrosilylation of allenes with primary and secondary phenylsilanes. It shows high selectivity ...towards the production of branched allylsilanes with a wide range of allenes. It is worth mentioning that the catalytic loading of the palladium can be reduced to 500 ppm. This work opens a new front of using bidentate thiophene ligand as a reaction promoter in transition‐metal‐catalyzed organic reaction.
The indoor air quality is of prime importance for human daily life and health, for which the adsorbents like zeolites and silica‐gels are widely used for air dehumidification and harmful gases ...capture. Herein, we develop a pore‐nanospace post‐engineering strategy to optimize the hydrophilicity, water‐uptake capacity and air‐purifying ability of metal‐organic frameworks (MOFs) with long‐term stability, offering an ideal candidate with autonomous multi‐functionality of moisture control and pollutants sequestration. Through variant tuning of organic‐linkers carrying hydrophobic and hydrophilic groups in the pore‐nanospaces of prototypical UiO‐67, a moderately hydrophilic MOF (UiO‐67‐4Me‐NH2‐38 %) with high thermal, hydrolytic and acid‐base stability is screened out, featuring S‐shaped water sorption isotherms exactly located in the recommended comfortable and healthy ranges of relative humidity for indoor ventilation (45 %–65 % RH) and adverse health effects minimization (40–60 % RH). Its exceptional attributes of water‐uptake working capacity/efficiency, contaminants removal, recyclability and regeneration promise a great potential in confined indoor environment application.
A moderately hydrophilic MOF of UiO‐67‐4Me‐NH2‐38 % with high thermal, hydrolytic and acid‐base stability has been obtained by a pore‐nanospace post‐engineering strategy, which shows ideal S‐shaped water‐sorption isotherm, high water‐uptake working capacity and efficiency in the ASHRAE recommended humidity range, and prior capture ability of harmful organic and inorganic vapors, providing a promising candidate for autonomous indoor humidity control and air purification.
Comprehensive Summary
By simplifying the π‐bridge unit, a nonfused ring electron acceptor (NFREA) BM‐2F was designed and synthesized with several high‐yield steps. The specific molecular structure ...features of BM‐2F are planar molecular backbone and out‐of‐plane side chain, which is favorable for charge transport and can suppress the over‐aggregation. BM‐2F based neat and blend films display obvious face‐on molecular orientation. Specially, D18:BM‐2F based blend film can form good bicontinuous interpenetrating network. More excitingly, a power conversion efficiency of 16.15% was achieved with D18:BM‐2F based photovoltaic devices, which is the highest one based on NFREAs. Our researches manifest that NFREA is a promising direction for low‐cost and high‐performance organic solar cells.
We designed a novel nonfused ring electron acceptor (BM‐2F), which can be obtained by four‐step high‐yield synthetic steps and is of 3D molecular structure. With D18 as polymer donor, the devices can afford a champion power conversion efficiency of 16.15% and display high FOM value, demonstrating great potential for future commercial application.
Humic substances (humics) are ubiquitous in terrestrial and aquatic environments where they can serve as electron acceptors for anaerobic oxidation of organic compounds. Methane is a powerful ...greenhouse gas, as well as the least reactive organic molecule. Anaerobic oxidation of methane (AOM) coupled to microbial reduction of various electron acceptors plays a crucial role in mitigating methane emissions. Here, we reported that humics could serve as terminal electron acceptors for AOM using enriched nitrate-reducing AOM microorganisms. AOM coupled to the reduction of humics was demonstrated based on the production of 13C-labelled carbon dioxide, and AOM activity was evaluated with different methane partial pressures and electron acceptor concentrations. After three-cycle reduction, both AOM activity and copy numbers of the archaea 16S rRNA and mcrA genes were the highest when anthraquinone-2,6-disulfonic acid and anthraquinone-2-sulfonic acid were electron acceptors. The high-throughput sequencing results suggested that ANME-2d were the dominant methane oxidation archaea after humics reduction, although the partner bacteria NC10 trended downward, other reported humics reduction bacteria (Geobactor and Anammox) appeared. The potential electron transfer models from ANME-2d to humics were proposed. These results enable a better understanding of available electron acceptors for AOM in natural environments and broaden our insight into the significant role of ANME-2d.
Display omitted
•Humics can serve as electron acceptors for anaerobic oxidation of methane (AOM).•AOM activity is the highest with AQDS and AQS after three-cycle reduction.•ANME-2d are the dominant methane oxidation archaea throughout the experiments.•Other reported humics reduction bacteria appear after three-cycle reduction.•The distinguishing electron transfer models between nitrate and humics reduction are proposed.
Spinal long-term potentiation (LTP) at C-fiber synapses is hypothesized to underlie chronic pain. However, a causal link between spinal LTP and chronic pain is still lacking. Here, we report that ...high-frequency stimulation (HFS; 100 Hz, 10 V) of the mouse sciatic nerve reliably induces spinal LTP without causing nerve injury. LTP-inducible stimulation triggers chronic pain lasting for more than 35 days and increases the number of calcitonin gene-related peptide (CGRP) terminals in the spinal dorsal horn. The behavioral and morphological changes can be prevented by blocking NMDA receptors, ablating spinal microglia, or conditionally deleting microglial brain-derived neurotrophic factor (BDNF). HFS-induced spinal LTP, microglial activation, and upregulation of BDNF are inhibited by antibodies against colony-stimulating factor 1 (CSF-1). Together, our results show that microglial CSF1 and BDNF signaling are indispensable for spinal LTP and chronic pain. The microglia-dependent transition of synaptic potentiation to structural alterations in pain pathways may underlie pain chronicity.
Display omitted
•HFS triggers synaptic plasticity of CGRP afferents and chronic pain•LTP-inducible HFS activates spinal microglia through CSF1 signaling•Microglial BDNF is essential for HFS-induced spinal LTP and chronic pain
Zhou et al. characterize chronic pain behaviors triggered by LTP-inducible HFS without nerve injury. They identify that HFS-induced LTP is accompanied by an increase in CGRP terminals in the spinal dorsal horn. Activation of neuronal CSF1-microglial BDNF signaling is indispensable for the synaptic and structural plasticity underlying HFS-induced chronic pain.
The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex-catalyzed homogeneous ...hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24 000 TON and 12 000 h–1 TOF) and excellent chemoselectivities with various aldehydes, ketones, imines, and even N-heteroarenes. The preference for 1,2-reduction over 1,4-reduction makes this method an efficient way to prepare allylic alcohols and amines. Meanwhile, efficient hydrogenation of the challenging N-heteroarenes is also furnished with excellent functional group tolerance. Mechanistic studies and control experiments demonstrated that a CoIH complex functions as a strong hydride donor in the catalytic cycle. Each cobalt intermediate on the catalytic cycle was characterized, and a plausible outer-sphere mechanism was proposed. Noteworthy, external inorganic base plays multiple roles in this reaction and functions in almost every step of the catalytic cycle.
Display omitted
•One iron catalyst showing multiple chemoselectivity.•General substrate scope (up to 56 example) and excellent selectivity (99% yield & selectivity)•High efficiency towards aldehydes ...(TONs up to 100,000)•Excellent functional group tolerance.
Hydrogenation of different types of unsaturated substrates with a single catalyst has always been a challenge for transition-metal-based catalysts. In this paper, an iron tetraphosphine complex shows high catalytic efficiency for selective hydrogenation of aldehydes, conjugated ketones and nitroarenes in the presence of other easily reduced functional groups like ketone, alkenyl, ester and alkynyl groups. The catalytic efficiency, chemoselectivity and robustness of this Fe/P2C‑PPh22NBn2 catalyst found its merit in the preparation of several important drug intermediates. A diamagnetic trans-iron dihydride complex formed under the reaction conditions was supposed to be an on-cycle catalytically active species. We are looking forward to the application of this method in pharmaceutical and fine chemical industries.
PDF
