Efficient tuning of the Pt nano-particle mono-dispersion on Vulcan XC-72R by selective pre-treatment and electrochemical evaluation of hydrogen oxidation and oxygen reduction reactions

The effect of chemical pre-treatment of the carbon support used for deposition of Pt nano-particles is reported. Data on particle size, distribution and their electocatalytic activity toward hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) are reported. Vulcan XC-72R carbon was pre-treated with 5% HNO₃, 0.07 M H₃PO₄, 0.2 M KOH and 10% H₂O₂. The properties of carbon supports were studied by N₂ adsorption and X-ray photoelectron spectroscopy (XPS). Chemical reduction with ethylene glycol (EG) was used to synthesize Pt on carbon supports and the differences in catalyst morphology were characterized using CO chemisorption, X-ray diffraction, energy dispersive X-ray analysis and transmission electron microscope techniques. The electrocatalytic activity of Pt/C catalysts toward HOR and ORR was examined by cyclic voltammetry (CV) on a rotating ring-disk electrode (RRDE) and compared with E-Tek Pt/C. The ORR was predominantly involved via four-electron process with the first electron transfer being the rate-determining step. However, the specific activity and mass activity were greatly influenced by the pre-treatment employed.     

Experimental Study on the Activities of Al and Ca in Ferrosilicon

Metallurgical and Materials Transactions B - Experiments were carried out to determine the activities of Al and Ca in liquid ferrosilicon (with about 50 wt pct Si) at...     

Biodiversity of Bacteriocin-Producing Lactic Acid Bacteria from Mexican Regional Cheeses and their Contribution to Milk Fermentation

The aim of this work was to examine the biodiversity of bacteriocin-producing lactic acid bacteria from homemade cheeses produced in Veracruz (México) and assess their contribution as adjunct cultures in dairy products. Ninety-three presumptive bacteriocinogenic strains were detected by direct antagonism assays and 29 of them were active against Enterococcus faecalis NRRL-B537, Listeria innocua 062 AST, or Listeria monocytogenes ATCC19115 by the well diffusion test using cell-free supernatants, adjusted to pH 6.0 to exclude inhibition by organic acids. Positive isolates were identified by partial sequencing of the 16s rDNA as Pediococcus acidilactici (four isolates), Enterococcus faecium (17 isolates), Lactobacillus plantarum (six isolates) and Lactobacillus fermentum (two isolates). RAPD-PCR discriminated seven groups with a 50% similarity and revealed the presence of the same isolates. The coding genes for the synthesis of plantaricin EF, plantaricin JK, plantaricin N, plantaricin NC8 and the inducing peptide plantaricin A were detected by PCR in L. plantarum. Similarly, enterocin P and pediocin PA-1 genes were amplified from Enterococcus and Pediococcus genomic DNA, respectively. Overall, co-culturing of bacteriocin producing Lactobacillus and Pediococcus strains with the dairy starter Lactococcus lactis IPLA947 did not interfere with milk acidification. Lactose consumption, acidification rate and production of lactic acid were unchanged. Nonetheless, higher levels of acetic acid, ethanol and succinic acid were detected depending on the strain. Our results demonstrate the diversity of bacteriocinogenic species in homemade Mexican cheeses which may be used as adjunct cultures to enhancing safety of this well-appreciated cheese while providing a richer range of metabolites.     

A dimensional analysis of creativity and mental illness: Do anxiety and depression symptoms predict creative cognition, creative accomplishments, and creative self-concepts?

The link, if any, between creativity and mental illness is one of the most controversial topics in modern creativity research. The present research assessed the relationships between anxiety and depression symptom dimensions and several facets of creativity: divergent thinking, creative self-concepts, everyday creative behaviors, and creative accomplishments. Latent variable models estimated effect sizes and their confidence intervals. Overall, measures of anxiety, depression, and social anxiety predicted little variance in creativity. Few models explained more than 3% of the variance, and the effect sizes were small and inconsistent in direction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Playing prosocial video games increases empathy and decreases schadenfreude.

Past research provided abundant evidence that exposure to violent video games increases aggressive tendencies and decreases prosocial tendencies. In contrast, research on the effects of exposure to prosocial video games has been relatively sparse. The present research found support for the hypothesis that exposure to prosocial video games is positively related to prosocial affect and negatively related to antisocial affect. More specifically, two studies revealed that playing a prosocial (relative to a neutral) video game increased interpersonal empathy and decreased reported pleasure at another's misfortune (i.e., schadenfreude). These results lend further credence to the predictive validity of the General Learning Model (Buckley & Anderson, 2006) for the effects of media exposure on social tendencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Logic-embedded vectors for intracellular partitioning, endosomal escape, and exocytosis of nanoparticles

A new generation of nanocarriers, logic-embedded vectors (LEVs), is endowed with the ability to localize components at multiple intracellular sites, thus creating an opportunity for synergistic control of redundant or dual-hit pathways. LEV encoding elements include size, shape, charge, and surface chemistry. In this study, LEVs consist of porous silicon nanocarriers, programmed for cellular uptake and trafficking along the endosomal pathway, and surface-tailored iron oxide nanoparticles, programmed for endosomal sorting and partitioning of particles into unique cellular locations. In the presence of persistent endosomal localization of silicon nanocarriers, amine-functionalized nanoparticles are sorted into multiple vesicular bodies that form novel membrane-bound compartments compatible with cellular secretion, while chitosan-coated nanoparticles escape from endosomes and enter the cytosol. Encapsulation within the porous silicon matrix protects these nanoparticle surface-tailored properties, and enhances endosomal escape of chitosan-coated nanoparticles. Thus, LEVs provide a mechanism for shielded transport of nanoparticles to the lesion, cellular manipulation at multiple levels, and a means for targeting both within and between cells.     

Drug delivery: Logic‐Embedded Vectors for Intracellular Partitioning,Endosomal Escape,and Exocytosis of Nanoparticles (Small 23/2010)

A new generation of nanocarriers, logic‐embedded vectors (LEVs), is endowed with the ability to localize components at multiple intracellular sites, thus creating an opportunity for synergistic control of redundant or dual‐hit pathways. LEV encoding elements include size, shape, charge, and surface chemistry. In this study, LEVs consist of porous silicon nanocarriers, programmed for cellular uptake and trafficking along the endosomal pathway, and surface‐tailored iron oxide nanoparticles, programmed for endosomal sorting and partitioning of particles into unique cellular locations. In the presence of persistent endosomal localization of silicon nanocarriers, amine‐functionalized nanoparticles are sorted into multiple vesicular bodies that form novel membrane‐bound compartments compatible with cellular secretion, while chitosan‐coated nanoparticles escape from endosomes and enter the cytosol. Encapsulation within the porous silicon matrix protects these nanoparticle surface‐tailored properties, and enhances endosomal escape of chitosan‐coated nanoparticles. Thus, LEVs provide a mechanism for shielded transport of nanoparticles to the lesion, cellular manipulation at multiple levels, and a means for targeting both within and between cells.