Fabrication of poly(vinyl alcohol)-polyaniline nanofiber/graphene hydrogel for high-performance coin cell supercapacitor

Electroactive polymer hydrogel offers several advantages for electrical devices, including straightforward synthesis, high conductivity, excellent redox behavior, structural robustness, and outstanding mechanical properties. Here, we report an efficient strategy for generating polyvinyl alcohol-polyaniline-multilayer graphene hydrogels (PVA-PANI-MLGHDGs)with excellent scalability and significantly improved mechanical, electrical, and electrochemical properties; the hydrogels were then utilized in coin cell supercapacitors. Production can proceed through the simple formation of boronate (-O-B-O-) bonds between PANI and PVA chains; strong intermolecular interactions between MLG, PANI, and PVA chains contribute to stronger and more rigid HDGs. We identified the optimal amount of PVA (5 wt.%) that produces a nanofiber-like PVA-PANI HDG with better charge transport properties than PANI HDGs produced by earlier approaches. The PVA-PANI-MLG HDG demonstrated superior tensile strength (8.10 MPa) and higher specific capacitance (498.9 F/cm2, 166.3 F/cm3, and 304.0 F/g) than PVA-PANI HDGs without MLG. The remarkable reliability of the PVA-PANI-MLG HDG was demonstrated by 92.6% retention after 3000 cycles of galvanostatic charge-discharge. The advantages of this HDG mean that a coin cell supercapacitor assembled using it is a promising energy storage device for mobile and miniaturized electronics. © 2020 by the authors.1

A pyrene–poly(acrylic acid)–polyrotaxane supramolecular binder network for high-performance silicon negative electrodes

Although being incorporated in commercial lithium‐ion batteries for a while, the weight portion of silicon monoxide (SiOx, x ≈ 1) is only less than 10 wt% due to the insufficient cycle life. Along this line, polymeric binders that can assist in maintaining the mechanical integrity and interfacial stability of SiOx electrodes are desired to realize higher contents of SiOx. Herein, a pyrene–poly(acrylic acid) (PAA)– polyrotaxane (PR) supramolecular network is reported as a polymeric binder for SiOx with 100 wt%. The noncovalent functionalization of a carbon coating layer on the SiOx is achieved by using a hydroxylated pyrene derivative via the π–π stacking interaction, which simultaneously enables hydrogen bonding interactions with the PR– PAA network through its hydroxyl moiety. Moreover, the PR's ring sliding while being crosslinked to PAA endows a high elasticity to the entire polymer network, effectively buffering the volume expansion of SiOx and largely mitigating the electrode swelling. Based on these extraordinary physicochemical properties of the pyrene–PAA–PR supramolecular binder, the robust cycling of SiOx electrodes is demonstrated at commercial levels of areal loading in both half‐cell and full‐cell configurations

Highly elastic polyrotaxane binders for mechanically stable lithium hosts in lithium‐metal batteries

Despite their unparalleled theoretical capacity, lithium‐metal anodes suffer from well‐ known indiscriminate dendrite growth and parasitic surface reactions. Conductive scaffolds with lithium uptake capacity are recently highlighted as promising lithium hosts, and carbon nanotubes (CNTs) are an ideal candidate for this purpose because of their capability of percolating a conductive network. However, CNT networks are prone to rupture easily due to a large tensile stress generated during lithium uptake– release cycles. Herein, CNT networks integrated with a polyrotaxane‐incorporated poly(acrylic acid) (PRPAA) binder via supramolecular interactions are reported, in which the ring‐sliding motion of the polyrotaxanes endows extraordinary stretchability and elasticity to the entire binder network. In comparison to a control sample with inelastic binder (i.e., poly(vinyl alcohol)), the CNT network with PRPAA binder can endure a large stress during repeated lithium uptake–release cycles, thereby enhancing the mechanical integrity of the corresponding electrode over battery cycling. As a result, the PRPAA‐incorporated CNT network exhibits substantially improved cyclability in lithium–copper asymmetric cells and full cells paired with olivine‐LiFePO4, indicating that high elasticity enabled by mechanically interlocked molecules such as polyrotaxanes can be a useful concept in advancing lithium‐metal batteries

Inhibition of parasite invasion by monoclonal antibody against epidermal growth factor-like domain of Plasmodium vivax merozoite surface protein 1 paralog

The Plasmodium vivax merozoite surface protein 1 paralog (PvMSP1P), which has epidermal growth factor (EGF)-like domains, was identified as a novel erythrocyte adhesive molecule. This EGF-like domain (PvMSP1P-19) elicited high level of acquired immune response in patients. Antibodies against PvMSP1P significantly reduced erythrocyte adhesion activity to its unknown receptor. To determine PvMSP1P-19-specific antibody function and B-cell epitopes in vivax patients, five monoclonal antibodies (mAbs) and 18-mer peptides were generated. The mAb functions were determined by erythrocyte-binding inhibition assay and invasion inhibition assay with P. knowlesi. B-cell epitopes of PvMSP1P-19 domains were evaluated by peptide microarray. The pvmsp1p-19 sequences showed limited polymorphism in P. vivax worldwide isolates. The 1BH9-A10 showed erythrocyte binding inhibitory by interaction with the N-terminus of PvMSP1P-19, while this mAb failed to recognize PkMSP1P-19 suggesting the species-specific for P. vivax. Other mAbs showed cross-reactivity with PkMSP1P-19. Among them, the 2AF4-A2 and 2AF4-A6 mAb significantly reduced parasite invasion through C-terminal recognition. The linear B-cell epitope in naturally exposed P. vivax patient was identified at three linear epitopes. In this study, PvMSP1P-19 N-terminal-specific 1BH9-A10 and C-terminal-specific 2AF4 mAbs showed functional activity for epitope recognition suggesting that PvMSP1P may be useful for vaccine development strategy for specific single epitope to prevent P. vivax invasion.Publisher PDFPeer reviewe

Chromosome-level genome assembly of a regenerable maize inbred line A188.

BACKGROUND The maize inbred line A188 is an attractive model for elucidation of gene function and improvement due to its high embryogenic capacity and many contrasting traits to the first maize reference genome, B73, and other elite lines. The lack of a genome assembly of A188 limits its use as a model for functional studies. RESULTS Here, we present a chromosome-level genome assembly of A188 using long reads and optical maps. Comparison of A188 with B73 using both whole-genome alignments and read depths from sequencing reads identify approximately 1.1 Gb of syntenic sequences as well as extensive structural variation, including a 1.8-Mb duplication containing the Gametophyte factor1 locus for unilateral cross-incompatibility, and six inversions of 0.7 Mb or greater. Increased copy number of carotenoid cleavage dioxygenase 1 (ccd1) in A188 is associated with elevated expression during seed development. High ccd1 expression in seeds together with low expression of yellow endosperm 1 (y1) reduces carotenoid accumulation, accounting for the white seed phenotype of A188. Furthermore, transcriptome and epigenome analyses reveal enhanced expression of defense pathways and altered DNA methylation patterns of the embryonic callus. CONCLUSIONS The A188 genome assembly provides a high-resolution sequence for a complex genome species and a foundational resource for analyses of genome variation and gene function in maize. The genome, in comparison to B73, contains extensive intra-species structural variations and other genetic differences. Expression and network analyses identify discrete profiles for embryonic callus and other tissues