Nonflammable Phosphate-Based Electrolyte for Safe and Stable Potassium Batteries Enabled by Optimized Solvation Effect.

Current potassium-ion batteries (PIBs) are limited in safety and lifetime owing to the lack of suitable electrolyte solutions. To address these issues, herein, we report an innovative non-flammable electrolyte design strategy that leverages an optimal moderate solvation phosphate-based solvent which strikes a balance between solvation capability and salt dissociation ability, leading to superior electrochemical performance. The formulated electrolyte simultaneously exhibits the advantages of low salt concentration (only 0.6 M), low viscosity, high ionic conductivity, high oxidative stability, and safety. Our electrolyte also promotes the formation of self-limiting inorganic-rich interphases at the anode surface, alongside robust cathode-electrolyte interphase on iron-based Prussian blue analogues, mitigating electrode/electrolyte side reactions and preventing Fe dissolution. Notably, the PIBs employing our electrolyte exhibit exceptional durability, with 80 % capacity retention after 2,000 cycles at high-voltage of 4.2 V in a coin cell. Impressively, in a larger scale pouch cell, it maintains over 81 % of its initial capacity after 1,400 cycles at 1 C-rate with high average Coulombic efficiency of 99.6 %. This work represents a significant advancement toward the realization of safe, sustainable, and high-performance PIBs.

Chloro-Functionalized Ether-Based Electrolyte for High-Voltage and Stable Potassium-Ion Batteries.

Ether-based electrolyte is beneficial to obtaining good low-temperature performance and high ionic conductivity in potassium ion batteries. However, the dilute ether-based electrolytes usually result in ion-solvent co-intercalation of graphite, poor cycling stability, and hard to withstand high voltage cathodes above 4.0 V. To address the aforementioned issues, an electron-withdrawing group (chloro-substitution) was introduced to regulate the solid-electrolyte interphase (SEI) and enhance the oxidative stability of ether-based electrolytes. The dilute (~0.91 M) chloro-functionalized ether-based electrolyte not only facilitates the formation of homogeneous dual halides-based SEI, but also effectively suppress aluminum corrosion at high voltage. Using this functionalized electrolyte, the K||graphite cell exhibits a stability of 700 cycles, the K||Prussian blue (PB) cell (4.3 V) delivers a stability of 500 cycles, and the PB||graphite full-cell reveals a long stability of 6000 cycles with a high average Coulombic efficiency of 99.98 %. Additionally, the PB||graphite full-cell can operate under a wide temperature range from -5 °C to 45 °C. This work highlights the positive impact of electrolyte functionalization on the electrochemical performance, providing a bright future of ether-based electrolytes application for long-lasting, wide-temperature, and high Coulombic efficiency PIBs and beyond.

Green Ether Electrolytes for Sustainable High-voltage Potassium Ion Batteries.

Ether-based electrolytes are promising for secondary batteries due to their good compatibility with alkali metal anodes and high ionic conductivity. However, they suffer from poor oxidative stability and high toxicity, leading to severe electrolyte decomposition at high voltage and biosafety/environmental concerns when electrolyte leakage occurs. Here, we report a green ether solvent through a rational design of carbon-chain regulation to elicit steric hindrance, such a structure significantly reducing the solvent's biotoxicity and tuning the solvation structure of electrolytes. Notably, our solvent design is versatile, and an anion-dominated solvation structure is favored, facilitating a stable interphase formation on both the anode and cathode in potassium-ion batteries. Remarkably, the green ether-based electrolyte demonstrates excellent compatibility with K metal and graphite anode and a 4.2 V high-voltage cathode (200 cycles with average Coulombic efficiency of 99.64 %). This work points to a promising path toward the molecular design of green ether-based electrolytes for practical high-voltage potassium-ion batteries and other rechargeable batteries.

Robust and accuracy calibration method for a binocular camera using a coding planar target.

High-accuracy binocular camera calibration is a vital basis of precise binocular vision 3D measurement. In this work, a high-precision and robust binocular camera calibration method based on a coding target is proposed. First, a coding target with the simple patterns is designed. Every corner on the coding target has a unique code number, which can make the identification of homonymous corners easier and more valuable, even if the target is partially occluded. The decoding of the coding target is rapid, robust, and accurate at a complex background. Subsequently, the zenith and azimuth angles are introduced in the proposed calibration method to study the effect of the orientation of the coding target on the stability of calibration results and improve the robustness of the calibration results. Finally, to fully utilize the 3D information of the calibration corners on the coding target, we combine the reprojection and 3D geometric constraints to propose a multi-constraint optimization method for refining the parameters of binocular camera and improving the accuracy of binocular camera calibration. The comparison experiments have been done to verify the performance of the proposed calibration method. The standard deviations of the intrinsic and extrinsic parameters are greatly decreased, compared with Zhang's method. The mean reprojection and 3D geometric errors calculated by the proposed method have a large reduction. And the application experiment furtherly validates the effectiveness of the proposed method.

High-precision and rapid binocular camera calibration method using a single image per camera.

This study proposes a precise and rapid binocular camera calibration (BCC) method based on a stereo target composed of 12 coded planar targets on which each calibration corner has a unique coded number. Unlike Zhang's method which requires numerous pairs of images in a binocular calibration process and fails to realize the matching of homonymous corners in the case of the incomplete target projection, the proposed method can implement an accurate BCC using a single calibration image per camera even in the case of target incompete projection. The proposed method greatly decreases the complexity of the calibration process. An optimization method based on multi-constraint is also presented to improve the accuracy of the BCC. The reprojection error and the 3D measurement errors are combined to evaluate the precision of the BCC more comprehensively. A binocular camera is calibrated by utilizing the proposed method and Zhang's method for comparison. The reprojection error and 3D measurement errors are remarkably reduced by applying the proposed method. The supplementary experiment further verifies the advantage of the proposed optimization method.

Polygalaxanthone III downregulates inflammation in the lipopolysaccharide-stimulated RAW264.7 macrophages: A quantibody array analysis.

Polygala japonica Houtt. (PJ), a member of the Polygala L. family that is suggested to exhibit detoxification properties in traditional Chinese medicine, is often used to treat upper respiratory tract infections. The anti-inflammatory effects of four main components of PJ (POL, PS-XLIX, PS-E, and PS-F) were examined using the LPS(0.3 µg·mL-1)-stimulated RAW264.7 macrophage model. The levels of NO, ROS, and iNOS were examined to analyze the anti-inflammatory activity of POL. Additionally, the levels of extracellular inflammation-related cytokines and chemokines were measured using quantibody array. The KEGG pathway analysis was performed to examine the anti-inflammatory mechanism of POL. The levels of NO in the POL-pretreated group were significantly downregulated when compared with those in the PS-E-pretreated, PS-F-pretreated, and PS-XLIX-pretreated groups. POL significantly inhibited the changes of iNOS, ROS, and inflammatory factors caused by LPS stimulation (p < 0.001). The expression levels of IL21 and GM-CSF were examined using qPCR, while those of JAK-STAT signaling pathway-related proteins in the LPS-stimulated RAW264.7 macrophages were analyzed using western blotting. POL significantly downregulated the expression of IL-21 and GM-CSF. The anti-inflammatory mechanism of POL is mediated through the JAK-STAT pathway. Thus, this study demonstrated that POL is an anti-inflammatory component of PJ and elucidated its mechanism.

Transmission of a Novel Genotype of Hepatitis E Virus from Bactrian Camels to Cynomolgus Macaques.

Hepatitis E virus (HEV) is zoonotic and a major cause of acute viral hepatitis worldwide. Recently, we identified a novel HEV genotype 8 (HEV8) in Bactrian camels in Xinjiang, China. However, the epidemiology, pathogenicity, and zoonotic potential of HEV8 are unclear. Here, we present the prevalence of HEV8 in China and investigate its pathogenicity and cross-species transmission in cynomolgus macaques. Fresh fecal and milk samples from Bactrian camels collected from four provinces/regions in China were screened for HEV RNA by reverse transcriptase PCR (RT-PCR). An HEV8-positive sample was used to inoculate two cynomolgus macaques to examine the potential for cross-species infection. The pathogenicity of HEV8 was analyzed by testing HEV markers and liver function during the study period and histopathology of liver biopsy specimens at 3, 13, and 25 weeks postinoculation. Extrahepatic replication was tested by using reverse transcriptase quantitative PCR (RT-qPCR) and immunofluorescence assays. The overall prevalence of HEV8 RNA in Chinese Bactrian camels was 1.4% (4/295), and positive samples were found in three different provinces/regions in China. Histopathology confirmed acute and chronic HEV8 infections in the two monkeys. Multiple tissues were positive for HEV RNA and ORF2 proteins. Renal pathology was observed in the monkey with chronic hepatitis. Whole-genome sequencing showed only 1 to 3 mutations in the HEV8 in the fecal samples from the two monkeys compared to that from the camel. HEV8 is circulating in multiple regions in China. Infection of two monkeys with HEV8 induced chronic and systemic infections, demonstrating the high potential zoonotic risk of HEV8.IMPORTANCE It is estimated that one-third of the world population have been exposed to hepatitis E virus (HEV). In developed countries and China, zoonotic HEV strains are responsible for almost all acute and chronic HEV infection cases. It is always of immediate interest to investigate the zoonotic potential of novel HEV strains. In 2016, we discovered a novel HEV genotype, HEV8, in Bactrian camels, but the epidemiology, zoonotic potential, and pathogenicity of the virus were unknown. In the present study, we demonstrated that HEV8 was circulating in multiple regions in China and was capable of infecting cynomolgus macaques, a surrogate for humans, posing high risk of zoonosis. Chronic hepatitis, systemic infection, and renal pathology were observed. Collectively, these data indicate that HEV8 exhibits a high potential for zoonotic transmission. Considering the importance of Bactrian camels as livestock animals, risk groups, such as camelid meat and milk consumers, should be screened for HEV8 infection.

Facilitating Phase Evolution for a High-Energy-Efficiency, Low-Cost O3-Type NaxCu0.18Fe0.3Mn0.52O2 Sodium Ion Battery Cathode.

The phase transition and lattice parameter evolution of O3 structure commonly occurs in O3-type sodium ion battery (SIB) cathodes, which might enlarge the voltage hysteresis and lower the energy efficiency. Given that the cost is one of the issues discouraging the application of SIBs in large-scale energy storage, here we focus on Co/Ni-free NaxCu0.18Fe0.3Mn0.52O2 (x = 0.8, 0.85, 0.9) and propose a convenient strategy to reduce the voltage hysteresis. It is found that when the Na content is 0.8, the highest energy efficiency of 95.4% after activation is achieved (2.5-4.0 V, 50 mA g-1, the 50th cycle), in addition to a satisfactory capacity retention (about 0.056% decay per cycle). The further characterizations reveal that Na0.8Cu0.18Fe0.3Mn0.52O2 owns a gentle O3-P3 phase transition process and does not undergo O3 phase lattice parameter evolution. The key point lies in the attainability of the O3/P3 composite of the material. This work will provide a simple strategy for the rational design of O3-type cathodes with a high energy efficiency and might offer inspiration to search for layered oxides with a higher O3/P3 critical Na content through element adjustments.

Identification of candidate synovial membrane biomarkers after Achyranthes aspera treatment for rheumatoid arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease whose main symptom is a heightened inflammatory response in synovial tissues. To verify the anti-arthritic activities of Achyranthes aspera and its possible therapy-related factors on the pathogenesis of RA, the saponins in A. aspera root were isolated and identified to treat the collagen-induced arthritis (CIA) rats. Phytochemical analysis isolated and identified methyl caffeate, 25-S-inokosterone, 25-S-inokosterone ß-D-glucopyranosyl 3-(O-ß-D-glucopyranosyloxy)-oleanolate, and ß-D-glucopyranosyl 3-(O-ß-D-galactopyranosyl (1→2)(O-ß-D-glucopyranosyloxy)-oleanolate as main compounds in the root of A. aspera. Proteomics was performed to determine the differentially expressed proteins in either inflamed or drug-treated synovium of CIA rats. Treatment resulted in dramatically decreased paw swelling, proliferation of inflammatory cells, and bone degradation. Fibrinogen, procollagen, protein disulfide-isomerase A3, and apolipoprotein A-I were all increased in inflamed synovial tissues and were found to decrease when administered drug therapy. Furthermore, Alpha-1-antiproteinase and manganese superoxide dismutase were both increased in drug-treated synovial tissues. The inhibition of RA progression shows that A. aspera is a promising candidate for future treatment of human arthritis. Importantly, the total saponins found within A. aspera are the active component. Finally, autoantigens such as fibrinogen and collagen could act as inducers of RA due to their aggravation of inflammation. Given this, it is possible that the vimentin and PDIA3 could be the candidate biomarkers specific to Achyranthes saponin therapy for rheumatoid arthritis in synovial membrane.

Development of a One Step Reverse Transcription-Loop-Mediated Isothermal Amplification System for a Highly Sensitive Detection of Rabbit Hepatitis E Virus.

BACKGROUND: Hepatitis E virus (HEV) is a major cause of acute viral hepatitis in areas with poor sanitation. Rabbit is one of important animal reservoirs of the virus. Reverse transcription-loop-mediated isothermal amplification (RT-LAMP) system is a novel nucleic acid amplification assay, for which the specificity and sensitivity are much higher than that of conventional PCR. However, previously reported RT-LAMP system cannot detect rabbit HEV, which was identified recently and seems to be another potential source of human HEV infection. METHODS: In this study, genotype 4 HEV strains and rabbit HEV strains were used to verify the applicability of the previously reported HEV RT-LAMP. A new specific one step RT-LAMP system was developed and evaluated to amplify rabbit HEV RNA. In order to test the sensitivity of the newly-developed assay, serial dilutions (from 5 x 103 to 5 x 10-1/µL) of the rabbit HEV RNA were used as template to be detected by RT-LAMP, real-time RTPCR, and nested RT-PCR. Specificity of the new assay was further evaluated using HAV, HBV, and HCV. With this new assay, 46 rabbit fecal samples were retrospectively investigated with real-time RT-PCR and nested RTPCR in parallel. RESULTS: The detection limit of this newly-developed RT-LAMP assay reached as low as 10 copies/reaction and no cross-reactivity was observed with other hepatitis viruses including hepatitis A, B, and C virus, which indicated that this assay has much higher sensitivity and specificity than that of nested RT-PCR and real time RT-PCR. Furthermore, among 46 rabbit fecal samples, there were four positive samples determined by those three assays and one positive sample only detected by HEV RT-LAMP and real-time RT-PCR. CONCLUSIONS: Using a combination of sensitivity, specificity, and evaluation of clinical samples, this study provides the first data on the usefulness of RT-LAMP in the diagnosis of rabbit HEV RNA.

Albuminuria is Suggested as a Potential Health Screening Biomarker for Senior Citizens and General Population with Hypertension or Diabetes in China.

BACKGROUND: To evaluate the possibility of albuminuria as a screening biomarker for seniors or general population with hypertension and diabetes. METHODS: 478 health check-up individuals were enrolled. Albumin to creatinine ratio (ACR) was calculated by testing urinary albumin and creatinine of spot urine sample. Each urine sample was also analyzed by the routine urine test in parallel with ACR. Potential risk factors associated with the presence of albuminuria were analyzed using independent t-test or chi-square test. RESULTS: The total prevalence of albuminuria was 11.9%, and women had a higher positive rate (14.0%) than men (10.6%). Ageing, fasting plasma glucose, and systolic blood pressure were significantly associated with the presence of albuminuria. Individuals are highly probable to have albuminuria when their routine urine test shows positive of urea glucose, red blood cells or urea protein. CONCLUSIONS: Albuminuria should be suggested as a potential health screening biomarker in senior citizens and general population with hypertension and diabetes.

Methods Comparison and Bias Estimation of Three Distinct Biochemistry Analytical Systems in One Clinical Laboratory Using Patient Samples.

BACKGROUND: In China, one laboratory usually owns more than one diagnostic device or reagent kit measuring the same analyte and this situation causes great troubles for quality control and traceability. To determine if the different devices yield equivalent results, the correlation coefficients and predicted bias between three distinct bio-chemistry analyzers in our lab were evaluated. METHODS: 40 analytes were detected and used to evaluate method performance and comparability of results between different analyzers. The Vitros5600 and Hitachi7170 analyzers were separately compared with the Cobas 8000 analyzer according to Clinical and Laboratory Standards Institute (CLSI) guideline (EP9-A2). Within-day and between-day imprecision of the three analytical systems were calculated in accordance with CLSI guidelines EP15-A2. RESULTS: Comparing the Hitachi7170 with Cobas8000 analyzer, except for calcium, magnesium, chloride ion (CL-), and carbon dioxide, the other 36 analytes were closely correlated (R2 > 0.95), while 4 of the 36 analytes' predicted bias exceeded the acceptable criteria. As for the Vitros5600 and Cobas8000, except for albumin, sodium ion (NA+), magnesium, and chloride (CL), the other 13 analytes were closely correlated (R2 > 0.95), while 5 of the 13 analytes' predicted bias exceeded the acceptable criteria. CONCLUSIONS: Significant differences for several analytes between distinct analyzers were found; for some analytes the predicted bias between dry chemical analyzer and conventional wet chemical analyzer can reach 30%, which is worthy of our concern. When one analyte was detected on more than one device, a strict method comparison study should be performed regularly. Reference intervals should be validated and transferred from the Cobas 8000 to Vitros5600 when the bias cannot be adjusted.

A bimetallic sulfide FeCoS4@rGO hybrid as a high-performance anode for potassium-ion batteries.

We synthesized a low metal-to-sulfur atomic ratio (0.5) FeCoS4, exhibiting high reversible specific capacity. Reduced graphene oxide was covered on the surface to improve the cycling stability and rate performance further. Density functional theory calculations show that composite materials can effectively increase the adsorption energy and enhance the diffusion kinetics.

Restructuring Electrolyte Solvation by a Partially and Weakly Solvating Cosolvent toward High-Performance Potassium-Ion Batteries.

Ether-based electrolytes are among the most important electrolytes for potassium-ion batteries (PIBs) due to their low polarization voltage and notable compatibility with potassium metal. However, their development is hindered by the strong binding between K+ and ether solvents, leading to [K+-solvent] cointercalation on graphite anodes. Herein, we propose a partially and weakly solvating electrolyte (PWSE) wherein the local solvation environment of the conventional 1,2-dimethoxyethane (DME)-based electrolyte is efficiently reconfigured by a partially and weakly solvating diethoxy methane (DEM) cosolvent. For the PWSE in particular, DEM partially participates in the solvation shell and weakens the chelation between K+ and DME, facilitating desolvation and suppressing cointercalation behavior. Notably, the solvation structure of the DME-based electrolyte is transformed into a more cation-anion-cluster-dominated structure, consequently promoting thin and stable solid-electrolyte interphase (SEI) generation. Benefiting from optimized solvation and SEI generation, the PWSE enables a graphite electrode with reversible K+ (de)intercalation (for over 1000 cycles) and K with reversible plating/stripping (the K||Cu cell with an average Coulombic efficiency of 98.72% over 400 cycles) and dendrite-free properties (the K||K cell operates over 1800 h). We demonstrate that rational PWSE design provides an approach to tailoring electrolytes toward stable PIBs.

Interfacial Biomacromolecular Engineering Toward Stable Ah-Level Aqueous Zinc Batteries.

Interfacial instability within aqueous zinc batteries (AZBs) spurs technical obstacles including parasitic side reactions and dendrite failure to reach the practical application standards. Here, an interfacial engineering is showcased by employing a bio- derived zincophilic macromolecule as the electrolyte additive (0.037 wt%), which features a long-chain configuration with laterally distributed hydroxyl and sulfate anion groups, and has the propensity to remodel the electric double layer of Zn anodes. Tailored Zn2+-rich compact layer is the result of their adaptive adsorption that effectively homogenizes the interfacial concentration field, while enabling a hybrid nucleation and growth mode characterized as nuclei-rich and space-confined dense plating. Further resonated with curbed corrosion and by-products, a dendrite-free deposition morphology is achieved. Consequently, the macromolecule-modified zinc anode delivers over 1250 times of reversible plating/stripping at a practical area capacity of 5 mAh cm-2, as well as a high zinc utilization rate of 85%. The Zn//NH4V4O10 pouch cell with the maximum capacity of 1.02 Ah can be steadily operated at 71.4 mA g-1 (0.25 C) with 98.7% capacity retained after 50 cycles, which demonstrates the scale-up capability and highlights a "low input and high return" interfacial strategy toward practical AZBs.

Rational Regulation of High-Voltage Stability in Potassium Layered Oxide Cathodes.

Layered oxide cathode materials may undergo irreversible oxygen loss and severe phase transitions during high voltage cycling and may be susceptible to transition metal dissolution, adversely affecting their electrochemical performance. Here, to address these challenges, we propose synergistic doping of nonmetallic elements and in situ electrochemical diffusion as potential solution strategies. Among them, the distribution of the nonmetallic element fluorine within the material can be regulated by doping boron, thereby suppressing manganese dissolution through surface enrichment of fluorine. Furthermore, in situ electrochemical diffusion of fluorine from the surface into the bulk of the materials after charging reduces the energy barrier of potassium ion diffusion while effectively inhibiting irreversible oxygen loss under high voltage. The modified K0.5Mn0.83Mg0.1Ti0.05B0.02F0.1O1.9 layered oxide cathode exhibits a high capacity of 147 mAh g-1 at 50 mA g-1 and a long cycle life of 2200 cycles at 500 mA g-1. This work demonstrates the efficacy of synergistic doping and in situ electrochemical diffusion of nonmetallic elements and provides valuable insights for optimizing rechargeable battery materials.

Plant Exosome-like Nanoparticles as Biological Shuttles for Transdermal Drug Delivery.

Exosomes act as emerging transdermal drug delivery vehicles with high deformability and excellent permeability, which can be used to deliver various small-molecule drugs and macromolecular drugs and increase the transdermal and dermal retention of drugs, improving the local efficacy and drug delivery compliance. At present, there are many studies on the use of plant exosome-like nanoparticles (PELNVs) as drug carriers. In this review, the source, extraction, isolation, and chemical composition of plant exosomes are reviewed, and the research progress on PELNVs as drug delivery systems in transdermal drug delivery systems in recent years has elucidated the broad application prospect of PELNVs.

Molecular characterization of a feruloyl-CoA 6'-hydroxylase involved in coumarin biosynthesis in Clematis terniflora DC.

Coumarin is an important secondary metabolite that affects plant physiology. It is a lactone of cis-o-hydroxycinnamic acid and widely exists in medicinal plants. Clematis terniflora DC. is a plant belonging to Ranunculaceae and is rich in variety of coumarins. Feruloyl-CoA 6'-hydroxylase has been reported as a key enzyme in the formation of coumarin basic skeleton only in some common plants, however, its evidence in other species is still lacking especially for the biosynthesis of coumarins in C. terniflora. In the present study, we identified a feruloyl-CoA 6'-hydroxylase CtF6'H in C. terniflora, and functional characterization indicated that CtF6'H could hydroxylate feruloyl-CoA to 6-hydroxyferuloyl-CoA. Furthermore, the expression level of CtF6'H was differed among different tissues in C. terniflora, while under UV-B radiation, the level of CtF6'H was increased in the leaves. Biochemical characteristics and subcellular location showed that CtF6'H was mainly present in the cytosol. The crystal structure of CtF6'H was simulated by homology modeling to predict the potential residues affecting enzyme activity. This study provides the additional evidence of feruloyl-CoA 6'-hydroxylase in different plant species and enriches our understanding of biosynthetic mechanism of coumarin in C. terniflora.

Bond modulation of MoSe2+x driving combined intercalation and conversion reactions for high-performance K cathodes.

The urgent demand for large-scale global energy storage systems and portable electronic devices is driving the need for considerable energy density and stable batteries. Here, Se atoms are introduced between MoSe2 layers (denoted as MoSe2+x ) by bond modulation to produce a high-performance cathode for potassium-ion batteries. The introduced Se atoms form covalent Se-Se bonds with the Se in MoSe2, and the advantages of bond modulation are as follows: (i) the interlayer spacing is enlarged which increases the storage space of K+; (ii) the system possesses a dual reaction mechanism, and the introduced Se can provide an additional conversion reaction when discharged to 0.5 V, which improves the capacity further; (iii) the Se atoms confined between MoSe2 layers do not give rise to the shuttle effect. MoSe2+x is compounded with rGO (MoSe2+x -rGO) as a cathode for potassium-ion batteries and displays an ultrahigh capacity (235 mA h g-1 at 100 mA g-1), a long cycle life (300 cycles at 100 mA g-1) and an extraordinary rate performance (135 mA h g-1 at 1000 mA g-1 and 89 mA h g-1 at 2000 mA g-1). Pairing the MoSe2+x -rGO cathode with graphite, the full cell delivers considerable energy density compared to other K cathode materials. The MoSe2+x -rGO cathode also exhibits excellent electrochemical performance for lithium-ion batteries. This study on bond modulation driving combined intercalation and conversion reactions offers new insights into the design of high-performance K cathodes.

Genes cloning, sequencing and function identification of recombinant polyphenol oxidase isozymes for production of monomeric theaflavins from Camellia sinensis.

Theaflavins (TFs) are important quality compounds in black tea with a variety of biological activities. However, direct extraction of TFs from black tea is inefficient and costly. Therefore, we cloned two PPO isozymes from Huangjinya tea, termed HjyPPO1 and HjyPPO3. Both isozymes oxidized corresponding catechin substrates for the formation of four TFs (TF1, TF2A, TF2B, TF3), and the optimal catechol-type catechin to pyrogallol-type catechin oxidation rate of both isozymes was 1:2. In particular, the oxidation efficiency of HjyPPO3 was higher than that of HjyPPO1. The optimum pH and temperature of HjyPPO1 were 6.0 and 35 °C, respectively, while those of HjyPPO3 were 5.5 and 30 °C, respectively. Molecular docking simulation indicated that the unique residue of HjyPPO3 at Phe260 was more positive and formed a π-π stacked structure with His108 to stabilize the active region. In addition, the active catalytic cavity of HjyPPO3 was more conducive for substrate binding by extensive hydrogen bonding.