Functionalization of textile cotton fabric with reduced graphene oxide/MnO2/polyaniline based electrode for supercapacitor

In this work, a new cotton electrode has been synthesized by coating ternary materials of reduced graphene oxide (rGO), manganese dioxide (MnO2), and polyaniline (PANi) on textile cotton fabric. First, Graphene oxide was deposited on cotton fibers by a simple 'dip and dry' method and chemically reduced into rGO/cotton fabric. MnO2 nanoparticles were accumulated on rGO/cotton fabric by in situ chemical deposition method. PANi layer was coated on rGO/MnO2/cotton fabric by in situ oxidative polymerization technique. A thin PANi coating layer acts as a protective layer on rGO/MnO2/cotton fabric to restrain MnO2 nanoparticles and rGO from dissolution in H2SO4 acidic electrolyte. The specific surface area of cotton electrode was measured using the Brenauer-Emmett-Teller (BET) method. The cyclic voltammetry (CV) results show that the cotton electrode has good capacitive behavior. The ternary cotton electrode exhibits high specific capacitance values of 888 F g(-1) and 252 F g(-1) at a discharge current density of 1 A g(-1) and 25 A g(-1) in 1MH(2)SO(4) electrolyte solution. The high areal specific capacitance of 444 Fcm(-2) was achieved for as-fabricated electrode. Also, the cotton electrode retains around 70% of specific capacitance after 3000 cycles at charge-discharge current density of 15 A g(-1). The slow decrease in specific capacitance is observed with increased discharge current density which proves its excellent rate capability. These results of rGO/MnO2/PANi/cotton fabric electrode show that this can be an excellent electrode for supercapacitor in energy storage devices

Ionic partition and transport in multi-ionic channels: A Molecular Dynamics Simulation study of the OmpF bacterial porin

We performed all-atom molecular dynamics simulations studying the partition of ions and the ionic current through the bacterial porin OmpF and two selected mutants. The study is motivated by new interesting experimental findings concerning their selectivity and conductance behaviour at neutral pH. The mutations considered here are designed to study the effect of removal of negative charges present in the constriction zone of the wild type OmpF channel (which contains on one side a cluster with three positive residues and on the other side two negatively charged residues). Our results show that these mutations induce an exclusion of cations from the constriction zone of the channel, substantially reducing the flow of cations. In fact, the partition of ions inside the mutant channels is strongly inhomogeneous, with regions containing excess of cations and regions containing excess of anions. Interestingly, the overall number of cations inside the channel is larger than the number of anions in the two mutants, as in the OmpF wild type channel. We found that the differences in ionic charge inside these channels are justified by the differences in electric charge between the wild type OmpF and the mutants, following an electroneutral balance

Insights into anti-termination regulation of the hut operon in Bacillus subtilis: importance of the dual RNA-binding surfaces of HutP

The anti-termination protein, HutP, regulates the gene expression of the hut (histidine utilization) operon of Bacillus subtilis, by destabilizing the hut terminator RNA located upstream of the coding region encoding l-histidine degradation enzymes. On the basis of biochemical, in vivo and X-ray structural analyses, we now report that HutP uses its dual RNA-binding surfaces to access two XAG-rich regions (sites I and II) within the terminator RNA to mediate the destabilization process. In this process, HutP initiates destabilization at the 5′-end of its mRNA by binding to the first XAG-rich region (site I) and then accesses the second XAG-rich region (site II), located downstream of the stable G-C-rich segment of the terminator stem. By this action, HutP appears to disrupt the G-C-rich terminator stem, and thus prevents premature termination of transcription in the RNA segment preceding the regions encoding for the histidine degradation enzymes

Cold aqueous extracts of African marigold, Tagetes erecta for control tomato root knot nematode, Meloidogyne incognita

Cold aqueous extracts (20% w/v, 100 ml aliquots) of pre- and post-flowering whole plants, root and stem portions of Tagetes erecta were tested for their ability to control M. incognita in infested soil (10 kg) in pots planted with susceptible Lycopersicon esculentum. Plant height and leaf number were significantly greater in T. erecta treated L. esculentum than plants grown in untreated infested soils. Whole T. erecta plant extracts were more efficacious than stem extracts although both were more effective than root extracts and extracts from 40-day old plants were more efficacious than those from 70-day old plants. Root gall indices of L. esculentum treated with T. erecta plant extracts were significantly lower than untreated checks and comparable with carbofuran-treated plants. Similarly, fruit yield from plants treated with T. erecta extracts was significantly better than untreated checks and comparable with carbofuran-treated plants. The value of applying T. erecta extracts as an alternative to intercropping for farmers is discusse

Improved biosynthesis and characterization of silver nanoparticles using Laggera crispata (Vahl) Hepper and J.R.l Wood leaves extract

Biosynthesis of nanoparticles is attractive to researchers because some of the biologically active ingredients in the plants help in green synthesis. In this study, we have developed a single-step, cost-effective, and eco-friendly method for the synthesis of Silver nanoparticles (AgNPs) using the aqueous plant leaves extract of Laggera crispata (Vahl) Hpper and J.R.l Wood. AgNPs were biosynthesized using Laggera crispata (Vahl) Hpper and J.R.l Wood leaves extract as reducing, capping, and stabilizing agent. The AgNPs began to form just after the addition of aqueous extract of Laggera plant to the aqueous solution of Silver nitrate (AgNO3) at room temperature. The biosynthesized AgNPs were characterized by different techniques, such as Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), and UVVisible Spectroscopy. The absorption spectra obtained from UV-Visible spectroscopy showed a sharp Surface Plasmon Resonance (SPR) peak at 451 nm which confirmed the formation of AgNPs. The average particle size of AgNPs was 53 nm as determined by X-ray Diffraction measurement. The FTIR study showed characteristic peaks corresponding to the functional groups that act as capping and stabilizing agent to AgNPs

A Structural Study of Ion Permeation in OmpF Porin from Anomalous X‑ray Diffraction and Molecular Dynamics Simulations

OmpF, a multiionic porin from <i>Escherichia coli</i>, is a useful protypical model system for addressing general questions about electrostatic interactions in the confinement of an aqueous molecular pore. Here, favorable anion locations in the OmpF pore were mapped by anomalous X-ray scattering of Br^– ions from four different crystal structures and compared with Mg²⁺ sites and Rb⁺ sites from a previous anomalous diffraction study to provide a complete picture of cation and anion transfer paths along the OmpF channel. By comparing structures with various crystallization conditions, we find that anions bind in discrete clusters along the entire length of the OmpF pore, whereas cations find conserved binding sites with the extracellular, surface-exposed loops. Results from molecular dynamics simulations are consistent with the experimental data and help highlight the critical residues that preferentially contact either cations or anions during permeation. Analysis of these results provides new insights into the molecular mechanisms that determine ion selectivity in OmpF porin

Schizosaccharomyces pombe Dss1p Is a DNA Damage Checkpoint Protein That Recruits Rad24p, Cdc25p, and Rae1p to DNA Double-strand Breaks*

Schizosaccharomyces pombe Dss1p and its homologs function in multiple cellular processes including recombinational repair of DNA and nuclear export of messenger RNA. We found that Tap-tagged Rad24p, a member of the 14-3-3 class of proteins, co-purified Dss1p along with mitotic activator Cdc25p, messenger RNA export/cell cycle factor Rae1p, 19 S proteasomal factors, and recombination protein Rhp51p (a Rad51p homolog). Using chromatin immunoprecipitation, we found that Dss1p recruited Rad24p and Rae1p to the double-strand break (DSB) sites. Furthermore, Cdc25p also recruited to the DSB site, and its recruitment was dependent on Dss1p, Rad24p, and the protein kinase Chk1p. Following DSB, all nuclear Cdc25p was found to be chromatin-associated. We found that Dss1p and Rae1p have a DNA damage checkpoint function, and upon treatment with UV light Δdss1 cells entered mitosis prematurely with indistinguishable timing from Δrad24 cells. Taken together, these results suggest that Dss1p plays a critical role in linking repair and checkpoint factors to damaged DNA sites by specifically recruiting Rad24p and Cdc25p to the DSBs. We suggest that the sequestration of Cdc25p to DNA damage sites could provide a mechanism for S. pombe cells to arrest at G2/M boundary in response to DNA damage

A Structural Study of Ion Permeation in OmpF Porin from Anomalous X‑ray Diffraction and Molecular Dynamics Simulations

OmpF, a multiionic porin from <i>Escherichia coli</i>, is a useful protypical model system for addressing general questions about electrostatic interactions in the confinement of an aqueous molecular pore. Here, favorable anion locations in the OmpF pore were mapped by anomalous X-ray scattering of Br^– ions from four different crystal structures and compared with Mg²⁺ sites and Rb⁺ sites from a previous anomalous diffraction study to provide a complete picture of cation and anion transfer paths along the OmpF channel. By comparing structures with various crystallization conditions, we find that anions bind in discrete clusters along the entire length of the OmpF pore, whereas cations find conserved binding sites with the extracellular, surface-exposed loops. Results from molecular dynamics simulations are consistent with the experimental data and help highlight the critical residues that preferentially contact either cations or anions during permeation. Analysis of these results provides new insights into the molecular mechanisms that determine ion selectivity in OmpF porin