A facile method for synthesis of polyaniline nanospheres and effect of doping on their electrical conductivity

The synthesis of polyaniline (PANI) nanospheres by a simple template-free method has been described. The polymerization of aniline in aqueous medium was accomplished using ammonium persulfate without any protonic acid. The UV-vis spectrum of PANI nanospheres displayed the characteristic absorption peak of π-π* transition of the benzenoid ring at 355 nm. The oxidation state of PANI nanospheres was identified with FT-IR spectroscopy by comparing the two bands at 1582 (ring stretching in quinoid unit) and 1498 cm(-1) (ring stretching in bezenoid unit). The X-ray diffraction patterns demonstrated the low crystalline nature of PANI nanospheres. The morphology of PANI nanospheres was spherical and the mean diameter of nanospheres was found in the range of 3-12 nm. The thermal behavior of PANI nanospheres was studied by thermogravimetric analysis. The effect of doping of HCl and H(2)SO(4) on PANI nanospheres was studied by measuring the current as a function of time of exposure. The high electrical conductivity of 6×10(-2) S cm(-1) was obtained for PANI nanospheres at their optimum doping state by 100 ppm HCl.     

One-dimensional titanate nanotube materials: heterogeneous solid catalysts for sustainable synthesis of biofuel precursors/value-added chemicals—a review

Journal of Materials Science - One-dimensional (1D) titanate nanotubes materials (protonated titanate nanotube (HTNT) and sodium titanate nanotube (NaTNT)) have been reported as low-cost and...     

Deposition of silver nanoparticles on dendrimer functionalized multiwalled carbon nanotubes: synthesis, characterization and antimicrobial activity

The nanohybrids composed of silver nanoparticles and aromatic polyamide functionalized multiwalled carbon nanotubes (MWCNTs) is successfully synthesized and tested for their antibacterial activity against different pathogens. Prior to deposition of silver nanoparticles, acid treated MWCNTs (MWCNTs-COOH) were successively reacted with p-phenylenediamine and methylmethacrylate to form series of NH2-terminated aromatic polyamide dendrimers on the surface of MWCNTs through Michael addition and amidation. Existence of high abundance of amine groups on the surface of functionalized MWCNTs (f-MWCNTs) provided sites for formation of silver nanoparticles by the reduction of aqueous solution of AgNO3. The silver nanoparticles formed in the resulted f-MWCNTs-Ag nanohybrids were determined to be face centered cubic (fcc) symmetry. The structure and nature of f-MWCNTs and f-MWCNTs-Ag nanohybrids were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction analysis (XRD), Raman spectroscopy and thermogravimetric analysis (TGA). The dispersion state of f-MWCNTs and immobilization of silver nanoparticles on the surface of f-MWCNTs were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Elemental composition of f-MWCNTs-Ag nanohybrids was determined by energy dispersive X-ray spectroscopy (EDS). The antimicrobial activity of f-MWCNTs-Ag nanohybrids were estimated against E. coli, P. aeruginosa and S. aureu and compared with MWCNTs-COOH and f-MWCNTs. The results indicate that functionalization of MWCNTs with aromatic polyamide dendrimers and successive deposition of Ag nanoparticles could play an important role in the enhancement of antimicrobial activity.     

Botrytis cinerea Loss and Restoration of Virulence during In Vitro Culture Follows Flux in Global DNA Methylation

Pathogenic fungi can lose virulence after protracted periods of culture, but little is known of the underlying mechanisms. Here, we present the first analysis of DNA methylation flux at a single-base resolution for the plant pathogen B. cinerea and identify differentially methylated genes/genomic regions associated with virulence erosion during in vitro culture. Cultures were maintained for eight months, with subcultures and virulence testing every month. Methylation-sensitive amplified polymorphisms were performed at monthly intervals to characterise global changes to the pathogen’s genome during culture and also on DNA from mycelium inoculated onto Arabidopsis thaliana after eight months in culture. Characterisation of culture-induced epialleles was assessed by whole-genome re-sequencing and whole-genome bisulfite sequencing. Virulence declined with time in culture and recovered after inoculation on A. thaliana. Variation detected by methylation-sensitive amplified polymorphisms followed virulence changes during culture. Whole-genome (bisulfite) sequencing showed marked changes in global and local methylation during culture but no significant genetic changes. We imply that virulence is a non-essential plastic character that is at least partly modified by the changing levels of DNA methylation during culture. We hypothesise that changing DNA methylation during culture may be responsible for the high virulence/low virulence transition in B. cinerea and speculate that this may offer fresh opportunities to control pathogen virulence.     

Pd nanoparticles deposited on poly(lactic acid) grafted carbon nanotubes: synthesis, characterization and application in Heck C-C coupling reaction

Herein we described the synthesis of a novel f-CNTs-Pd nanocatalyst by covalent grafting of poly(lactic acid) (PLA) onto carbon nanotubes (CNTs) and subsequent deposition of Pd nanoparticles. Prior to grafting of PLA, CNTs were oxidized with a mixture of HNO(3)/H(2)SO(4) and successively activated with thionyl chloride. The PLA grafted CNTs (f-CNTs) were then used as platform for in-situ deposition of Pd nanoparticles. The formation of f-CNTs-Pd nanocatalyst was analyzed by UV-vis, FTIR and Raman spectroscopy, powder XRD, energy dispersive spectroscopy and thermogravimetric analysis. The morphologies of the nanocatalyst were characterized using scanning and transmission electron microscopes. The f-CNTs stabilized Pd nanoparticles are found to be more effective in the promotion of Heck cross-coupling reaction between aryl halides and n-butyl acrylate. The f-CNTs-Pd nanocatalyst was regenerated for three cycles of reaction without any significant loss in its activity.     

Cover Image,Volume 98, Issue 5

The cover image, by Oluyinka A. Olukosi et al., is based on the Research Article Peptide supplementation to nutrient‐adequate diets enhanced internal egg quality during storage in hens at peak production, DOI: 10.1002/jsfa.8661 . Photo Credit: Oluyinka A. Olukosi, Scotland's Rural College

     

Wax Variation in Some Nigerian Oil Wells in Delta Field

Oil samples from five wells in the Delta field were analyzed for their wax deposition tendencies. Reservoir aging effect on the wax content of the oil was studied. Similarly, the effect of the depth of the reservoir on wax content of the oil was examined. A table of the rheological properties of these oils was provided. The magnitude of the wax present in each hydrocarbon fractions in the crude oil was determined. The results obtained compare favorably with few published data.     

Outdoor Path Loss Predictions Based on Extreme Learning Machine

Wireless Personal Communications - In a typical outdoor environment, the propagation of radio waves is usually random in nature, to the extent that the characterization of the wireless...