Na2.5 Cr0.5 Zr0.5 Cl6 : A New Halide-Based Fast Sodium-Ion Conductor.

All-solid-state batteries employing solid electrolytes (SEs) have received widespread attention due to their high safety. Recently, lithium halides are intensively investigated as promising SEs while their sodium counterparts are less studied. Herein, a new sodium-ion conductor with a chemical formula of Na2.5 Cr0.5 Zr0.5 Cl6 is reported, which exhibits high room temperature ionic conductivity of 0.1 mS cm-1 with low migration energy barrier of ≈0.41 eV. Na2.5 Cr0.5 Zr0.5 Cl6 has a Fm-3m structure with 41.67 mol.% of cationic vacancies owing to the occupation of Cr (8.33 mol.%) and Zr (8.33 mol.%) ions at Na sites. Supercell calculations show that the lowest columbic energy configuration has Cr/Zr/V (where V is the vacancy) clusters in the structure. Nonetheless, the clusters have mixed effects on the sodium ion conduction pathway, based on the Bond Valence Energy Landscape calculation. A global 3D Na-ion transport percolation network can be revealed in the lowest energy supercell. Effective pathways are connected through the NaCl6 and VCl6 nodes. Besides, Raman spectroscopy and 23 Na solid-state nuclear magnetic resonance spectroscopy further prove the tunable structure of the SEs with different Cr to Zr ratios. The optimization between the concentration of Na+ and vacancies is crucial to create an improved network of Na+ diffusion channels.

Self-Assembled Molecules with Asymmetric Backbone for Highly Stable Binary Organic Solar Cells with 19.7 % Efficiency.

The hole-transporting material (HTM), poly (3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT : PSS), is the most widely used material in the realization of high-efficiency organic solar cells (OSCs). However, the stability of PEDOT : PSS-based OSCs is quite poor, arising from its strong acidity and hygroscopicity. In addition, PEDOT : PSS has an absorption in the infrared region and high highest occupied molecular orbital (HOMO) energy level, thus limiting the enhancement of short-circuit current density (Jsc) and open-circuit voltage (Voc), respectively. Herein, two asymmetric self-assembled molecules (SAMs), namely BrCz and BrBACz, were designed and synthesized as HTM in binary OSCs based on the well-known system of PM6 : Y6, PM6 : eC9, PM6 : L8-BO, and D18 : eC9. Compared with BrCz, BrBACz shows larger dipole moment, deeper work function and lower surface energy. Moreover, BrBACz not only enhances photon harvesting in the active layer, but also minimizes voltage losses as well as improves interface charge extraction/ transport. Consequently, the PM6 : eC9-based binary OSC using BrBACz as HTM exhibits a champion efficiency of 19.70 % with a remarkable Jsc of 29.20 mA cm-2 and a Voc of 0.856 V, which is a record efficiency for binary OSCs so far. In addition, the unencapsulated device maintains 95.0 % of its original efficiency after 1,000 hours of storage at air ambient, indicating excellent long-term stability.

Evaluation of Cathode Electrodes in Lithium-Ion Battery: Pitfalls and the Befitting Counter Electrode.

Boosting energy density and reducing the cost of lithium-ion batteries are critical to accelerating their applications in transportation and grid energy storage. Battery design with increasing electrode thickness is an effective way to combine higher energy density and lower cost. However, the evaluation of electrodes with increased thickness is challenging and requires more attention. Here, some pitfalls are to be avoided and a reasonable evaluation strategy is provided for cathode electrodes regarding the choice of counter electrode. Though as the most common counter electrode, lithium metal anode is actually not suitable for evaluating cycling performance, which exhibits fast cell capacity decline, especially, in the case of areal capacity higher than 2 mAh cm-2 . Two commercial anode materials, graphite and Li4 Ti5 O12 (LTO) as the potential alternatives, are systematically evaluated and compared, demonstrating LTO as the more suitable choice. The thick cathode electrode coupled with LTO exhibits excellent rate capability, stable cycling performance, and easy interpretation of charge/discharge profile. The relationship between cell balance and battery performance is further analyzed in detail. This strategy enables a reasonable evaluation of the cathode electrodes and advances the designing of thick electrode.

Multi-Wavelength-Recognizable Memristive Devices via Surface Plasmon Resonance Effect for Color Visual System.

Photoelectric memristor has attracted many attentions thanks to their promising potential in optical communication chips and artificial vision systems. However, the implementation of an artificial visual system based on memristive devices remains a considerable challenge because most photoelectric memristors cannot recognize color. Herein, multi-wavelength recognizable memristive devices based on silver(Ag) nanoparticles (NPs) and porous silicon oxide (SiOx ) nanocomposites are presented. Rely on the effects of localized surface plasmon resonance (LSPR) and optical excitation of Ag NPs in SiOx , the set voltage of the device can be gradually reduced. Moreover, the current overshoot problem is alleviated to suppress conducting filament overgrowth after visible light irradiation with different wavelengths, resulting in diverse low resistance states (LRS). Taking advantage of the characteristics of controlled switching voltage and LRS resistance distribution, color image recognition is finally realized in the present work. X-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (C-AFM) show that the light irradiation plays an important role on resistive switching (RS) process: the photo-assisted Ag ionization leads to a significant reduction of set voltage and overshoot current. This work provides an effective method toward the development of multi-wavelength-recognizable memristive devices for future artificial color vision system.

Asymmetric Bio-epoxidation of Unactivated Alkenes.

Optically active epoxides play important roles in pharmaceutical, agricultural and fine chemical syntheses. There are many chiral medications with pharmacodynamic activity in nature that can be synthesized by chiral epoxides. In recent years, researchers have developed a variety of biocatalysts for the asymmetric epoxidation of alkenes, which use oxygen or hydrogen peroxide as eco-friendly and low-cost oxidants, to provide better chemo-, regio- and stereoselectivity under moderate reaction conditions. In this paper, the advances, opportunities and challenges of the asymmetric epoxidation of unactive alkenes by biocatalyst are reviewed.

Polyoxometalate-Viologen Thermochromic Hybrids for Organic Amine Detectors and Memristors with Temperature-Regulating Resistance Switching Characteristics.

There are relatively few reports on the combination of viologen and polyoxometalates (POMs). Herein, we successfully synthesized three viologen-POM-based compounds by in situ transformation of ligands under hydrothermal conditions, namely, {MII(1,4-cby)2[H2(γ-Mo8O26)]}·nH2O (1: M = Ni, n = 4; 2: M = Co, n = 6), and [NiII(1,3-cby)(H2O)4(ß-Mo8O26)0.5]·2H2O (3) (1,4-cby·Cl = 1-(4-carboxy-benzyl)-[4,4']bipyridinyl-1-ium, 1,3-cby·Cl = 1-(3-carboxy-benzyl)-[4,4']bipyridinyl-1-ium). Isostructural compounds 1 and 2 exhibit two-dimensional (2D) layer structures with POMs as linking nodes, while compound 3 shows a one-dimensional (1D) metal-organic chain with dissociative POM anions. When the temperature increases, compounds 1-3 show good reversible thermochromism properties and also have a fluorescence quenching effect. Moreover, compounds 1-3 can also be used as detectors for organic amines, especially in the atmosphere of ammonia, ethylenediamine, and diethylamine with an obvious discoloration effect. In addition, compound 1 was used as a material for the preparation of memristors with superior properties (distinct temperature-adjusted resistive switching properties). It shows bipolar resistive switching (RS) behavior at different temperatures of 20, 50, and 100 °C. The results show that the 1-based memristor has good thermal stability, which is important for high-temperature environment applications. It also shows that crystalline viologen-POM-based compounds are ideal candidates for making memristors.

Detection of Cytb Point Mutation (G143A) that Confers High-Level Resistance to Pyraclostrobin in Glomerella cingulata Using LAMP Method.

Glomerella leaf spot (GLS) caused by Glomerella cingulata is a newly emerging disease that results in severe defoliation and fruit spots in apples. In China, the compound of pyraclostrobin and tebuconazole was registered to control GLS in 2018 and has achieved excellent control efficiency. In this study, we showed that the high-level resistant isolates of G. cingulata to pyraclostrobin, caused by the point mutation at codon 143 (GGT→GCT, G143A) in the cytochrome b gene, has appeared in apple orchards in Shandong Province in 2020, and the resistance frequency was 4.8%. Based on the genotype of the resistant isolates, we developed a loop-mediated isothermal amplification (LAMP) assay for detection of the pyraclostrobin resistance. The LAMP assay was demonstrated to have good specificity, sensitivity, and repeatability, and it exhibited high accuracy in detecting pyraclostrobin resistance in the field. This study reported the resistance status of GLS to pyraclostrobin in Shandong Province and developed a molecular tool for the detection of pyraclostrobin resistance, which is of practical significance for the scientific control of GLS.

Gradient Graphdiyne Induced Copper and Oxygen Vacancies in Cu0.95 V2 O5 Anodes for Fast-Charging Lithium-Ion Batteries.

Vacancies can significantly affect the performance of metal oxide materials. Here, a gradient graphdiyne (GDY) induced Cu/O-dual-vacancies abundant Cu0.95 V2 O5 @GDY heterostructure material has been prepared as a competitive fast-charging anode material. Cu0.95 V2 O5 self-catalyzes the growth of gradient GDY with rich alkyne-alkene complex in the inner layer and rich alkyne bonds in the outer layer, leading to the formation of Cu and O vacancies in Cu0.95 V2 O5 . The synergistic effect of vacancies and gradient GDY results in the electron redistribution at the hetero-interface to drive the generation of a built-in electric field. Thus, the Li-ion transport kinetics, electrochemical reaction reversibility and Li storage sites of Cu0.95 V2 O5 are greatly enhanced. The Cu0.95 V2 O5 @GDY anodes show excellent fast-charging performance with high capacities and negligible capacity decay for 10 000 cycles and 20 000 cycles at extremely high current densities of 5 A g-1 and 10 A g-1 , respectively. Over 30 % of capacity can be delivered in 35 seconds.

Nanoarchitectonics on Electrosynthesis and Assembly of Conjugated Metallopolymers.

In contrast to edge-on and face-on orientations, end-on uniaxial conjugated polymers have the theoretical possibility of providing a macroscopic crystalline film. However, their fabrication is insurmountable due to sluggishly thermodynamic equilibrium states. Herein, we report the programmatic pathway to fabricate nanoarchitectonics on end-on uniaxial conjugated metallopolymers by surface-initiated simultaneous electrosynthesis and assembly. Self-assembled monolayer (SAM) with bottom-up oriented electroactive molecules as a temple allows orientation, stacking, and reactive addition of monomers triggered by switching alternative redox reactions as well as crystallization of small molecules. Repeating the same reaction can repair the unreactive site on the SAM and dynamically and statistically ensure maximum iterative coverage with ideal linear coefficients between optical or electrical responses and iterative times. The resulting nanoarchitectonics on uniaxially assembled end-on polymers over centimeter-sized areas have a subnanometer-uniform morphology and exhibit ultrahigh modulus as well as an inorganic indium tin oxides and the highest conductance among conjugated molecular monolayers. Their memristive devices provide quantitative electrical and optical responses as a function of molecular length, bias, and iterative junctions. Precise processing of nanoarchitectonics as an electrically assisted assembly or printing technique can present sophisticated optoelectric functions and dimensional batch-to-batch consistency for micro-sized organic materials and electronics.

Enzymatic approaches to site-selective oxidation of quinoline and derivatives.

Enzyme-mediated oxidation has been a green and efficient strategy for preparation of derivative chemicals from quinoline and its structural analogues. Herein, we report the progress made to date in enzymatic methods to oxidation of the pyridine moieties of quinoline and its structural analogues 1,2,3,4-tetrahydroquinoline, isoquinoline and 1,2,3,4-tetrahydroisoquinoline, including whole cell- and isolated enzyme-based transformations. In addition, methods to tune the site selectivity of the course of enzymatic transformation are also addressed, in particular the protein engineering approaches.

Combined photoredox/engineered P450 enzymatic direct dioxygen-functionalization of arylalkanes to chiral acyloins.

To date, the examples of difunctionalization of alkanes to directly incorporate two functional groups are very limited. In this study, we combined photoorgano redox catalysis and P450 biocatalysts to obtain dioxygen-functionalization of α/ß-C-H bonds of arylalkanes in a straightforward manner. The synthesis of enantiomerically chiral acyloins through a one-pot two-step photoredox/P450-catalyzed cascade reaction is described. Two P450 mutants with stereocomplementary bio-oxidation were obtained using mutagenesis technology and were able to asymmetrically hydroxylate ketones to acyloins with excellent ee values, which were further proved to be efficient on a wide range of substrates. Moreover, a photoredox synthesis of ketones in situ was developed by the direct carbonylation of aromatic methyl C-H bonds and subsequently combined with the aerobic P450-biocatalytic enantioselective hydroxylation of intermediate ketones, thus providing a green and sustainable approach towards optically pure acyloins.

Multienzyme Redox System with Cofactor Regeneration for Cyclic Deracemization of Sulfoxides.

Optically pure sulfoxides are noteworthy compounds applied in a wide range of industrial fields; however, the biocatalytic deracemization of racemic sulfoxides is challenging. Herein, a high-enantioselective methionine sulfoxide reductase A (MsrA) was combined with a low-enantioselective styrene monooxygenase (SMO) for the cyclic deracemization of sulfoxides. Enantiopure sulfoxides were obtained in >90 % yield and with >90 % enantiomeric excess (ee) through dynamic "selective reduction and non-selective oxidation" cycles. The cofactors of MsrA and SMO were subsequently regenerated by the cascade catalysis of three auxiliary enzymes through the consumption of low-cost D-glucose. Moreover, this "one-pot, one-step" cyclic deracemization strategy exhibited a wide substrate scope toward various aromatic, heteroaromatic, alkyl and thio-alkyl sulfoxides. This system proposed an efficient strategy for the green synthesis of chiral sulfoxide.

Zeolite-Based Memristive Synapse with Ultralow Sub-10-fJ Energy Consumption for Neuromorphic Computation.

The development of neuromorphic computation faces the appreciable challenge of implementing hardware with energy consumption on the level of a femtojoule per synaptic event to be comparable with the energy consumption of human brain. Controllable ultrathin conductive filaments are needed to achieve such extremely low energy consumption in memristive synapses but their formation is difficult to control owing to their stochastic morphology and unexpected overgrowth. Herein, a zeolite-based memristive synapse is demonstrated for the first time, in which Ag exchange in the sub-nanometer pore closely resembles synaptic Ca2+ dynamics across biomembrane channel. Particularly, the confined ultrasmall pore and low Ag ion migration barrier give the zeolite-based memristive synapse ultralow energy consumption below 10 fJ per synaptic spike, on par with the biological counterpart. Experimental results reveal that the gradual memristive effect is attributed to the dimension modulation of Ag clusters. In addition to emulating inherent cognitive functions through electrical stimulations, the experience-dependent transition of short-term plasticity to long-term plasticity using a chemical modulation method is achieved by treating the initial Ag quantity as a learning experience. The proposed memristors can be used to develop highly efficient memristive neural networks and are considered as a candidate for application in neuromorphic computation.

CSN6 inhibition suppresses pancreatic adenocarcinoma metastasis via destabilizing the c-Fos protein.

Deubiquitinase (DUB) can reverse the ubiquitin signal, and participate in virtually all aspects of cancer progression. Thus, DUB represents an attractive target for development of anticancer drugs. However, little is known about DUB which can be used as drug targets. Here, we found that the constitutive photomorphogenic 9 (COP9) signalosome complex subunit 6 (COPS6/CSN6), a DUB belongs to JAMM/MPN domain-associated metallopeptidases(JAMMs) class, was highly expressed in pancreatic adenocarcinoma(PAAD) tissues. High expression of CSN6 was associated with tumor TNM stage and metastasis in PAAD patients. Moreover, we demonstrated that CSN6 promoted invasion and metastasis through regulating forkhead box protein A1 (FOXA1) in PAAD cells. Re-expression of FOXA1 rescued the decreased invasion and metastasis caused by CSN6 knockdown, whereas inhibition of FOXA1 alleviated the pro-metastasis effect induced by CSN6 overexpression. Further, CSN6 regulated the expression of FOXA1 via c-Fos in PAAD cells. Mechanistically, CSN6 stabilized c-Fos protein by binding to it and decreasing its ubiquitination. Our work identified CSN6 as a targeting-permissible deubiquitinase, and CSN6 inhibition maybe a potential treatment strategy for PAAD.

Graphdiyne Interface Engineering: Highly Active and Selective Ammonia Synthesis.

A freestanding 3D graphdiyne-cobalt nitride (GDY/Co2 N) with a highly active and selective interface is fabricated for the electrochemical nitrogen reduction reaction (ECNRR). Density function theory calculations reveal that the interface-bonded GDY contributes an unique p-electronic character to optimally modify the Co-N compound surface bonding, which generates as-observed superior electronic activity for NRR catalysis at the interface region. Experimentally, at atmospheric pressure and room temperature, the electrocatalyst creates a new record of ammonia yield rate (Y NH 3 ) and Faradaic efficiency (FE) of 219.72 µg h-1 mgcat. -1 and 58.60 %, respectively, in acidic conditions, higher than reported electrocatalysts. Such a catalyst is promising to generate new concepts, new knowledge, and new phenomena in electrocatalytic research, driving rapid development in the field of electrocatalysis.

Biodegradable Natural Pectin-Based Flexible Multilevel Resistive Switching Memory for Transient Electronics.

Transient electronics that can physically vanish in solution can offer opportunities to address the ecological challenges for dealing with the rapidly growing electronic waste. As one important component, it is desirable that memory devices combined with the transient feature can also be developed as secrecy information storage systems besides the above advantage. Resistive switching (RS) memory is one of the most promising technologies for next-generation memory. Herein, the biocompatible pectin extracted from natural orange peel is introduced to fabricate RS memory devices (Ag/pectin/indium tin oxides (ITO)), which exhibit excellent RS characteristics, such as forming free characteristic, low operating voltages (≈1.1 V), fast switching speed (<70 ns), long retention time (>104 s), and multilevel RS behaviors. The device performance is not degraded after 104 bending cycles, which will be beneficial for flexible memory applications. Additionally, instead of using acid solution, the Ag/pectin/ITO memory device can be dissolved rapidly in deionized water within 10 min thanks to the good solubility arising from ionization of its carboxylic groups, which shows promising application for green electronics. The present biocompatible memory devices based on natural pectin suggest promising material candidates toward enabling high-density secure information storage systems applications, flexible electronics, and green electronics.

Boosting the Reversibility of Sodium Metal Anode via Heteroatom-Doped Hollow Carbon Fibers.

Sodium (Na) metal anodes stand out with their remarkable capacity and natural abundance. However, the dendritic Na growth, infinite dimensional changes, and low Coulombic efficiency (CE) present key bottlenecks plaguing practical applications. Here, heteroatom-doped (nitrogen, sulfur) hollow carbon fibers (D-HCF) are rationally synthesized as a nucleation-assisting host to enable a highly reversible Na metal. The "sodiophilic" functional groups introduced by the heteroatom-doping and large surface area (≈1052 m2 g-1 ) synchronously contribute to a homogenous plating morphology with dissipated local current density. High "sodiophilicity" of the D-HCF is confirmed by first-principle calculations and experimental results, where strong adsorption energy of -3.52 eV with low Na+ nucleation overpotential of 3.2 mV at 0.2 mA cm-2 is realized. As such, highly reversible plating/stripping is achieved at 1.0 mA cm-2 with average CE approximating 99.52% over 600 cycles. The as-assembled Na@D-HCF symmetric cells exhibit a prolonged lifetime for 1000 h. A full-cell paired with Na3 V2 (PO4 )3 cathode further demonstrates stable electrochemical behavior for 200 cycles at 1 C along with excellent rate performance (102 mAh g-1 at 5 C). The results clearly show the effectiveness of the D-HCF in manipulating Na+ deposition and thus the significance of nucleation control in realizing dendrite-free metal anodes.

Photocatalytic Reduction of Graphene Oxide-TiO2 Nanocomposites for Improving Resistive-Switching Memory Behaviors.

Graphene oxide (GO)-based resistive-switching (RS) memories offer the promise of low-temperature solution-processability and high mechanical flexibility, making them ideally suited for future flexible electronic devices. The RS of GO can be recognized as electric-field-induced connection/disconnection of nanoscale reduced graphene oxide (RGO) conducting filaments (CFs). Instead of operating an electrical FORMING process, which generally results in high randomness of RGO CFs due to current overshoot, a TiO2 -assisted photocatalytic reduction method is used to generate RGO-domains locally through controlling the UV irradiation time and TiO2 concentration. The elimination of the FORMING process successfully suppresses the RGO overgrowth and improved RS memory characteristics are achieved in graphene oxide-TiO2 (Go-TiO2 ) nanocomposites, including reduced SET voltage, improved switching variability, and increased switching speed. Furthermore, the room-temperature process of this method is compatible with flexible plastic substrates and the memory cells exhibit excellent flexibility. Experimental results evidence that the combined advantages of reducing the oxygen-migration barrier and enhancing the local-electric-field with RGO-manipulation are responsible for the improved RS behaviors. These results offer valuable insight into the role of RGO-domains in GO memory devices, and also, this mild photoreduction method can be extended to the development of carbon-based flexible electronics.

A novel and simple spectrophotometric method for detection of nitrite in water.

A novel and simple spectrophotometric method is developed for the determination of nitrite in water by using the self-coupling diazotization reagent 2-amino-6-chlorobenzoic acid and UV light illumination. The method only involves one reagent and one step, which can be easily applied to the determination of nitrite and tolerates many foreign anions' effects under acidic conditions.

Enhancement of Exciton Emission from Multilayer MoS2 at High Temperatures: Intervalley Transfer versus Interlayer Decoupling.

It is very important to obtain a deeper understand of the carrier dynamics for indirect-bandgap multilayer MoS2 and to make further improvements to the luminescence efficiency. Herein, an anomalous luminescence behavior of multilayer MoS2 is reported, and its exciton emission is significantly enhanced at high temperatures. Temperature-dependent Raman studies and electronic structure calculations reveal that this experimental observation cannot be fully explained by a common mechanism of thermal-expansion-induced interlayer decoupling. Instead, a new model involving the intervalley transfer of thermally activated carriers from Λ/Γ point to K point is proposed to understand the high-temperature luminescence enhancement of multilayer MoS2 . Steady-state and transient-state fluorescence measurements show that both the lifetime and intensity of the exciton emission increase relatively to increasing temperature. These two experimental evidences, as well as a calculation of carrier population, provide strong support for the proposed model.