Achieving Synergistic Improvement in Dielectric and Energy Storage Properties of All-Organic Poly(Methyl Methacrylate)-Based Copolymers Via Establishing Charge Traps

How to achieve synergistic improvement of permittivity(ε_(r))and breakdown strength(E_(b))is a huge challenge for polymer dielectrics.Here,for the first time,theπ-conjugated comonomer(MHT)can simultaneously promote theε_(r)and E_(b)of linear poly(methyl methacrylate)(PMMA)copolymers.The PMMA-based random copolymer films(P(MMA-co-MHT)),block copolymer films(PMMA-b-PMHT),and PMMA-based blend films were prepared to investigate the effects of sequential structure,phase separation structure,and modification method on dielectric and energy storage properties of PMMA-based dielectric films.As a result,the random copolymer P(MMA-coMHT)can achieve a maximumε_(r)of 5.8 at 1 kHz owing to the enhanced orientation polarization and electron polarization.Because electron injection and charge transfer are limited by the strong electrostatic attraction ofπ-conjugated benzophenanthrene group analyzed by the density functional theory(DFT),the discharge energy density value of P(MMA-co-PMHT)containing 1 mol%MHT units with the efficiency of 80%reaches15.00 J cm^(-3)at 872 MV m^(-1),which is 165%higher than that of pure PMMA.This study provides a simple and effective way to fabricate the high performance of polymer dielectrics via copolymerization with the monomer of P-type semi-conductive polymer.

Direct detection of a single[4Fe-4S]cluster in a tungsten-containing enzyme:Electrochemical conversion of CO_(2) into formate by formate dehydrogenase

The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.

Hydrogenase as the basis for green hydrogen production and utilization

Hydrogenase is a paradigm of highly efficient biocatalyst for H_(2) production and utilization evolved in nature. A dilemma is that despite the high activity and efficiency expected for hydrogenases as promising catalysts for the hydrogen economy, the poor oxygen tolerance and low yield of hydrogenases largely hinder their practical application. In these years, the enigmas surrounding hydrogenases regarding their structures, oxygen tolerance, mechanisms for catalysis, redox intermediates, and proton-coupled electron transfer schemes have been gradually elucidated;the schemes, which can well couple hydrogenases with other highly efficient(in)organic and biological catalysts to build novel reactors and drive valuable reactions, make it possible for hydrogenases to find their niches. To see how scientists put efforts to tackle this issue and design novel reactors in the fields where hydrogenases play crucial roles, in this review,recent advances were summarized, including different strategies for protecting enzyme molecules from oxygen, enzyme-based assembling systems for H_(2) evolution in the photoelectronic catalysis, enzymatic biofuel cells for H_(2) utilization and storage and the efficient electricity-hydrogen-carbohydrate cycle for high-purity hydrogen and biofuel automobiles. Limitations and future perspectives of hydrogenasebased applications in H_(2) production and utilization with great impact are discussed. In addition, this review also provides a new perspective on the use of biohydrogen in healthcare beyond energy.

Chromosome-scale assembly and evolution of the tetraploid Salvia splendens (Lamiaceae) genome

Polyploidization plays a key role in plant evolution,but the forces driving the fate of homoeologs in polyploid genomes,i.e.,paralogs resulting from a whole-genome duplication(WGD)event,remain to be elucidated.Here,we present a chromosome-scale genome assembly of tetraploid scarlet sage(Salvia splendens),one of the most diverse ornamental plants.We found evidence for three WGD events following an older WGD event shared by most eudicots(theγevent).A comprehensive,spatiotemporal,genome-wide analysis of homoeologs from the most recent WGD unveiled expression asymmetries,which could be associated with genomic rearrangements,transposable element proximity discrepancies,coding sequence variation,selection pressure,and transcription factor binding site differences.The observed differences between homoeologs may reflect the first step toward sub-and/or neofunctionalization.This assembly provides a powerful tool for understanding WGD and gene and genome evolution and is useful in developing functional genomics and genetic engineering strategies for scarlet sage and other Lamiaceae species.

Pressurized Synchronous Extraction of Volatile Oils, Total Flavonoids and Tannic Acid from Artemisia argyi

[Objectives] This study aimed to optimize the conditions for pressurized synchronous extraction of volatile oils, total flavonoids and tannic acid from Artemisia argyi .[Methods] Single factor experiments and orthogonal experiments were conducted.[Results] Pressurization had a significant effect on the extraction rate of chemical constituents of A. argyi . The optimal conditions for pressurized synchronous extraction of volatile oils, total flavonoids and tannic acid from A. argyi were as follows: solvent concentration of 70%, solid to liquid ratio of 1∶ 30 (g/mL), extraction pressure of 0.9 MPa, extraction time of 40 min and extraction temperature of 90 ℃. Under the optimal extraction conditions, the yields of volatile oils, total flavonoids and tannic acid were 0.852%, 4.66% and 6.79%, respectively.[Conclusions] Compared with other extraction methods, the pressurized assistant solvent extraction method can achieve the synchronous extraction of volatile oils, total flavonoids and tannic acid from A. argyi . The process is stable, short in extraction time, high in solvent utilization rate and ideal in extraction effect of the three components from A. argyi .

Construction of an intranasal drug delivery system with hypothalamus-targeting nanoparticles

Dysfunction of the hypothalamus is associated with endocrine imbalances,growth abnormalities,and reproductive disorders.However,there is a lack of targeted treatment strategies focused on the hypothalamus.In this study,we constructed a multifunctional nanocarrier system(S@ANP)to directly target the hypothalamic neurokinin receptor 3(NK3R)via an intranasal delivery strat-egy.This system could overcome the primary obstacles in drug delivery for hypothalamus-related diseases.Under the guidance of a modified(Trp7,β-Ala8)-neurokinin A(4-10)peptide with cysteine,nanoparticles encapsulated with SB222200,an NK3R inhibitor,were found to readily penetrate hypothalamic cells with substantial loading capacity,encapsulation efficiency,and sustained release in vitro.Moreover,intranasal delivery represents an optimal delivery strategy that allows for a significant reduction in oral dosage and enables nanoparti-cles to bypass the blood-brain barrier and target relevant parts of the brain.The mucolytic agent N-acetyl-L-cysteine(NAC)was loaded into the nanopar-ticles(S@ANP+NAC)to increase mucosal solubility and intranasal delivery efficiency.In vivo evaluations showed that S@ANP+NAC could effectively tar-get the hypothalamus and modulate NK3R-regulated hypothalamic functions in mice.Due to its high hypothalamic targeting efficiency and low toxicity,this intranasal nanoparticle drug delivery system may serve as a potential strategy for precision therapy of hypothalamic disorders.

Ferroelectric catalytic BaTiO3-based composite insoles topromote healing of infected wounds:Analysis ofantibacterial efficacy and angiogenesis

Our feet are often subjected to moist and warm environments,which can promote the growth of harmful bacteria and the development of severe infection in wounds located in the foot.As a result,there is a need for new and innovative strategies to safely sterilize feet,when shoes are worn,to prevent any potential foot-related diseases.In this paper,we have produced a non-destructive,biocompatible and convenient-to-use insole by embedding a BaTiO3(BT)ferroelectric material into a conventional polydimethylsilane(PDMS)insole material to exploit a ferroelectric catalytic effect to promote the antibacterial and healing of infected wounds via the ferroelectric charges generated during walking.The formation of reactive oxygen species generated through a ferroelectric catalytic effect in the PDMS-BT composite is shown to increase the oxidative stress on bacteria and decrease both the activity of bacteria and the rate of formation of bacterial biofilms.In addition,the ferroelectric field generated by the PDMS-BT insole can enhance the level of transforming growth factor-beta and CD31 by influencing the endogenous electric field of a wound,thereby promoting the proliferation,differentiation of fibroblasts and angiogenesis.This work therefore provides a new route for antimicrobial and tissue reconstruction by integrating a ferroelectric biomaterial into a shoe insole,with significant potential for health-related applications.

Multiple Effects Tailoring the Self-organization Behaviors of Triphenylene Side-chain Liquid Crystalline Polymers via Changing the Spacer Length

Long-alkyl tail triphenylene （TP） side-chain liquid crystalline polymers （SCLCPs） with different spacer length （P-m-TP, m = 2, 3, 4, 6, 8, which is the number of carbon atom in the flexible alkyl spacers） have been successfully synthesized via free radical polymerization. The differential scanning calorimetry （DSC）, polarized light microscopy （POM）, ultraviolet-visible spectroscopy （UV- Vis）, wide-angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） measurements were performed to investigate the influence of multiple effects on the self-organization behaviors of P-m-TP, including steric effect, decoupling effect and π-π stacking effect. The experimental results revealed that P-m-TP （m = 2, 3, 4） formed the columnar phase which was developed by the TP moieties and the main chain as a whole, suggesting that the side-chains had strong steric effect even though the number of spacer length （m） exceeded 4. In addition, the clearing points （Tis） of the polymers were above 300 ℃. When m = 6 and 8, the polymers displayed hexagonal columnar phase and exhibited the low Tis （91 and 80 ℃ respectively）, originating from the self-assembly of triphenylene due to the decoupling effect and π-π stacking effect. This work offers a viable and inspiring pathway to control the phase transition temperature and phase structure ofTP SCLCPs via simply tailoring the spacer length and increasing the alkyl tail length of TP.

Graphene oxide/gallium nanoderivative as a multifunctional modulator of osteoblastogenesis and osteoclastogenesis for the synergistic therapy of implant-related bone infection

Currently,implant-associated bacterial infections account for most hospital-acquired infections in patients suffering from bone fractures or defects.Poor osseointegration and aggravated osteolysis remain great challenges for the success of implants in infectious scenarios.Consequently,developing an effective surface modification strategy for implants is urgently needed.Here,a novel nanoplatform(GO/Ga)consisting of graphene oxide(GO)and gallium nanoparticles(GaNPs)was reported,followed by investigations of its in vitro antibacterial activity and potential bacterium inactivation mechanisms,cytocompatibility and regulatory actions on osteoblastogenesis and osteoclastogenesis.In addition,the possible molecular mechanisms underlying the regulatory effects of GO/Ga nanocomposites on osteoblast differentiation and osteoclast formation were clarified.Moreover,an in vivo infectious microenvironment was established in a rat model of implant-related femoral osteomyelitis to determine the therapeutic efficacy and biosafety of GO/Ga nanocomposites.Our results indicate that GO/Ga nanocomposites with excellent antibacterial potency have evident osteogenic potential and inhibitory effects on osteoclast differentiation by modulating the BMP/Smad,MAPK and NF-κB signaling pathways.The in vivo experiments revealed that the administration of GO/Ga nanocomposites significantly inhibited bone infections,reduced osteolysis,promoted osseointegration located in implant-bone interfaces,and resulted in satisfactory biocompatibility.In summary,this synergistic therapeutic system could accelerate the bone healing process in implant-associated infections and can significantly guide the future surface modification of implants used in bacteria-infected environments.

Van der Waals ferroelectric transistors:the all-round artificial synapses for high-precision neuromorphic computing

State number,operation power,dynamic range and conductance weight update linearity are key synaptic device performance metrics for high-accuracy and low-power-consumption neuromorphic com-puting in hardware.However,high linearity and low power consump-tion couldn’t be simultaneously achieved by most of the reported synaptic devices,which limits the performance of the hardware.This work demonstrates van der Waals(vdW)stacked ferroelectric field-effect transistors(FeFET)with single-crystalline ferroelectric nanoflakes.Ferroelectrics are of fine vdW interface and partial polar-ization switching of multi-domains under electric field pulses,which makes the FeFETs exhibit multi-state memory characteristics and ex-cellent synaptic plasticity.They also exhibit a desired linear conduc-tance weight update with 128 conductance states,a sufficiently high dynamic range of G_(max)/G_(min)>120,and a low power consumption of 10 fJ/spike using identical pulses.Based on such an all-round device,a two-layer artificial neural network was built to conduct Modified Na-tional Institute of Standards and Technology(MNIST)digital num-bers and electrocardiogram(ECG)pattern-recognition simulations,with the high accuracies reaching 97.6%and 92.4%,respectively.The remarkable performance demonstrates that vdW-FeFET is of obvious advantages in high-precision neuromorphic computing applications.

Optimized strain performance in <001>-textured Bi_(0.5)Na_(0.5)TiO_(3)-based ceramics with ergodic relaxor state and core-shell microstructure

Herein,a high strain of ~0.3% with a small hysteresis of 43% is achieved at a low electric field of 4 kV/mm in the highly <001>-textured 0.97(0.76Bi_(0.5)Na_(0.5)TiO_(3)-0.24SrTiO_(3))-0.03NaNbO_(3)(BNT-ST-0.03NN)ceramics with an ergodic relaxor(ER)state,leading to a large normalized strain(d_(33)^(*))of 720 pm/V.The introduction of NN templates into BNT-ST induces the grain orientation growth and enhances the ergodicity.The highly <001>-textured BNT-ST-0.03NN ceramics display a pure ergodic relaxor state with coexisted ferroelectric R3c and antiferroelectric P4bm polar nanoregions(PNRs)on nanoscale.Moreover,due to the incomplete interdiffusion between the NN template and BNT-ST matrix,the textured ceramics present a core-shell structure with the antiferroelectric NN core,and thus the BNT-based matrix owns more R3c PNRs relative to the homogeneous nontextured samples.The high <001> crystallographic texture and more R3c PNRs both facilitate the relaxor-to-ferroelectric transition,leading to the low-field-driven high strain,while the ergodic relaxor state ensures a small hysteresis.Furthermore,the d_(33)^(*)value remains high up to 518 pm/V at 100℃ with an ultra-low hysteresis of 6%.

Improved dielectric constant and energy density of P(VDF-HFP)composites using NBT-xST(x=0,0.10,0.26)whiskers

The high-performance energy-storage dielectric capacitors are increasingly important due to their wide applications in high power electronics.Here,we fabricated a novel P(VDF-HFP)-based capacitor with surface-modified NBT-xST(x?0,0.10,0.26)whiskers,denoted as Dop@NBT-xST/P(VDF-HFP).The influences of ST content,fillers’volume fraction and electric field on the dielectric properties and energy-storage performance of the composites were investigated systematically.The results show that the dielectric constant monotonously increased with the increase of ST content and fillers’volume fraction.The composite containing 10.0 vol%NBT-0.26STwhiskers possessed a dielectric constant of 39 at 1 kHz,which was 5.6 times higher than that of pure P(VDF-HFP).It was noticed that the D-E loops of the composites became thinner and thinner with the increase of ST content.Due to the reduced remnant polarization,the composite with 5.0 vol%NBT-0.26STwhiskers achieved a high energy density of 6.18 J/cm3 and energy efficiency of approximately 57%at a relatively low electric field of 200 kV/mm.This work indicated that NBT-0.26ST whisker is a kind of potential ceramic filler in fabricating the dielectric capacitor with high discharged energy density and energy efficiency.