Flexible Perfluoropolyethers-Functionalized CNTs-Based UHMWPE Composites: A Study on Hydrogen Evolution, Conductivity and Thermal Stability

Flexible conductive composites based on ultra-high molecular weight polyethylene (UHMWPE) filled with multi-walled carbon nanotubes (CNTs) modified by perfluoropolyethers (PFPEs) were produced. The bonding of PFPE chains, added in 1:1 and 2:1 weight ratios, on CNTs influences the dispersion of nanotubes in the UHMWPE matrix due to the non-polar nature of the polymer, facilitating the formation of nanofillers-rich conductive pathways and improving composites' electrical conductivity (two to five orders of magnitude more) in comparison to UHMWPE-based nanocomposites obtained with pristine CNTs. Electrochemical atomic force microscopy (EC-AFM) was used to evaluate the morphological changes during cyclic voltammetry (CV). The decrease of the overpotential for hydrogen oxidation peaks in samples containing PFPE-functionalized CNTs and hydrogen production (approximately -1.0 V vs. SHE) suggests that these samples could find application in fuel cell technology as well as in hydrogen storage devices. Carbon black-containing composites were prepared for comparative study with CNTs containing nanocomposites

Flexible Perfluoropolyethers-Functionalized CNTs-Based UHMWPE Composites: A Study on Hydrogen Evolution, Conductivity and Thermal Stability

Flexible conductive composites based on ultra-high molecular weight polyethylene (UHMWPE) filled with multi-walled carbon nanotubes (CNTs) modified by perfluoropolyethers (PFPEs) were produced. The bonding of PFPE chains, added in 1:1 and 2:1 weight ratios, on CNTs influences the dispersion of nanotubes in the UHMWPE matrix due to the non-polar nature of the polymer, facilitating the formation of nanofillers-rich conductive pathways and improving composites’ electrical conductivity (two to five orders of magnitude more) in comparison to UHMWPE-based nanocomposites obtained with pristine CNTs. Electrochemical atomic force microscopy (EC-AFM) was used to evaluate the morphological changes during cyclic voltammetry (CV). The decrease of the overpotential for hydrogen oxidation peaks in samples containing PFPE-functionalized CNTs and hydrogen production (approximately −1.0 V vs. SHE) suggests that these samples could find application in fuel cell technology as well as in hydrogen storage devices. Carbon black-containing composites were prepared for comparative study with CNTs containing nanocomposites

Efficacy and safety of aripiprazole in the treatment of bipolar disorder: a systematic review

Abstract BACKGROUND: The current article is a systematic review concerning the efficacy and safety of aripiprazole in the treatment of bipolar disorder. METHODS: A systematic Medline and repositories search concerning the usefulness of aripiprazole in bipolar disorder was performed, with the combination of the words 'aripiprazole' and 'bipolar'. RESULTS: The search returned 184 articles and was last updated on 15 April 2009. An additional search included repositories of clinical trials and previous systematic reviews specifically in order to trace unpublished trials. There were seven placebo-controlled randomised controlled trials (RCTs), six with comparator studies and one with add-on studies. They assessed the usefulness of aripiprazole in acute mania, acute bipolar depression and during the maintenance phase in comparison to placebo, lithium or haloperidol. CONCLUSION: Aripiprazole appears effective for the treatment and prophylaxis against mania. The data on bipolar depression are so far negative, however there is a need for further study at lower dosages. The most frequent adverse effects are extrapyramidal signs and symptoms, especially akathisia, without any significant weight gain, hyperprolactinaemia or laboratory test changes

NAFION stabilized silver nanoparticles modified electrodes: characterization and use in electroanalysis

Spherical silver nanoparticles (10-30 nm) were synthesized modifying a published procedure1, and confirmed by TEM and UV-vis analysis. The Ag nanoparticles were used to modify Glassy Carbon (GC) Electrodes depositing onto the GC support a suspension of the nanomaterials in Nafion\uae. Electrodes were morphologically characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Stability in air and in solution and repeatability were evaluated and their electrochemical properties, compared with those of bare glassy carbon and Nafion-modified glassy carbon electrodes, were studied with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) measurements, using [Ru(NH3)6]Cl3 as model probe molecule. The modified electrodes show promising electroanalytical performances with very high current densities, probably due to the increase of the effective surface area, to a formation of a random array of nanoparticles on the Nafion\uae three-dimensional substrate with intermediate diffusional behaviour between planar and convergent2-3, and to a very small double layer capacitance. Applications exploiting the electrocatalytic properties of Ag for the detection of a model simple chlorinated compound (dichloromethane) and a more complex organic chlorinated compound (halothane) are presented. References [1] Z. Shervani, Y. Ikushima, M. Sato, H. Kawanami, Y. Hakuta, T. Yokoyama, T. Nagase, H. Kuneida, K. Aramaki, Colloid Polym Sci, (2008), 286, 403. [2] F.W. Campbell, R.G. Compton, Anal Bioanal Chem, (2010), 396, 241. [3] S.J. Xing, H. Xu, J.S. Chen, G.Y. Shi, L.T. Jin, J Electroanal Chem, (2011), 652, 60

Selection of moxifloxacin-resistant Staphylococcus aureus compared with five other fluoroquinolones

Fluoroquinolone-resistant mutants were selected from Staphylococcus aureus NCTC 8532 (F77), and two GrlA mutants of F77 (F193 and F194) with moxifloxacin, sparfloxacin, ofloxacin, grepafloxacin, levofloxacin and trovafloxacin. For mutants selected from F77, moxifloxacin, grepafloxacin and sparfloxacin selected preferentially for mutations in gyrA (Glu-88→Lys). Ofloxacin and trovafloxacin selected most commonly for mutations in grlA, conferring substitutions for Ser-80. Three mutants of F77 were shown to have substitutions in both GrlA (Phe-80) and GyrA (Lys-88). Of the mutants selected from F193 (GrlA Phe-80), restriction fragment length polymorphism analysis of gyrA showed that 76/94 had a mutation at codon 84; those analysed in detail all had the substitution Ser→Leu. Two mutants selected with grepafloxacin contained the substitution Lys-88. One mutant selected with trovafloxacin contained a novel mutation in gyrA substituting Gly-82→Cys. Of the mutants selected from F194 (GrlA Tyr-80), 6/8 had a mutation in gyrA codon 84; of which three contained Leu. The MICs of most agents for mutants selected from F193 and F194 were similar, irrespective of the mutation selected. No mutants had any changes in grlB, and only one had a mutation in gyrB giving rise to the novel substitution Asp-437→His. The mutations arising in first-step mutants were influenced by the fluoroquinolone used for selection. The phenotypes and genotypes of second-step mutants, derived from mutants with existing mutations in grlA, were similar, regardless of the selecting antibiotic

Repeated Evolutionary Changes of Leaf Morphology Caused by Mutations to a Homeobox Gene

SummaryElucidating the genetic basis of morphological changes in evolution remains a major challenge in biology [1–3]. Repeated independent trait changes are of particular interest because they can indicate adaptation in different lineages or genetic and developmental constraints on generating morphological variation [4–6]. In animals, changes to “hot spot” genes with minimal pleiotropy and large phenotypic effects underlie many cases of repeated morphological transitions [4–8]. By contrast, only few such genes have been identified from plants [8–11], limiting cross-kingdom comparisons of the principles of morphological evolution. Here, we demonstrate that the REDUCED COMPLEXITY (RCO) locus [12] underlies more than one naturally evolved change in leaf shape in the Brassicaceae. We show that the difference in leaf margin dissection between the sister species Capsella rubella and Capsella grandiflora is caused by cis-regulatory variation in the homeobox gene RCO-A, which alters its activity in the developing lobes of the leaf. Population genetic analyses in the ancestral C. grandiflora indicate that the more-active C. rubella haplotype is derived from a now rare or lost C. grandiflora haplotype via additional mutations. In Arabidopsis thaliana, the deletion of the RCO-A and RCO-B genes has contributed to its evolutionarily derived smooth leaf margin [12], suggesting the RCO locus as a candidate for an evolutionary hot spot. We also find that temperature-responsive expression of RCO-A can explain the phenotypic plasticity of leaf shape to ambient temperature in Capsella, suggesting a molecular basis for the well-known negative correlation between temperature and leaf margin dissection