A 59-Cobalt NMR Investigation of the Hydrogen/Deuterium Exchange Kinetics in Cobalt(III) Complexes

Currently, the hydrogen/deuterium exchange kinetics in cobalt(III) complexes are being investigated. In the presence of deuterated solvents, (e.g. D2 0 and CH3CH20D) the amine hydrogens in the complexes are exchanged for deuteriums. For the hexaamminecobalt(III) ion, 19 isotopmers (H18D0 to HOD 18) are possible. For the tris(ethylenediammine)cobalt(III) ion, 13 isotopmers (HI 2D0 to HOD 12) are possible. Each hydrogen/deuteruim exchange causes a shift in the observed 59Co resonance of approximately 6 ppm. The rate constant of the hydrogen-deuterium exchange for the first H-D exchange has been determined as a function of solvent. When the chosen solvent is D20, the rate constant is 1.09 x 10° sec 1 for the hexaamminecobalt(III) ion. In methanol-d, the rate constant is 1.82 x 10 4 sec \u27. Electronic effects of ligands have also been investigated. Experimental conditions (e.g., observation frequencies and solution parameters) and the representative NMR spectra are presented

Children’s particulate matter exposure characterization as part of the new hampshire birth cohort study

As part of the New Hampshire Birth Cohort Study, children 3 to 5 years of age participated in a personal PM2.5 exposure study. This paper characterizes the personal PM2.5 exposure and protocol compliance measured with a wearable sensor. The MicroPEM™ collected personal continuous and integrated measures of PM2.5 exposure and compliance data on 272 children. PM2.5, black carbon (BC), and brown carbon tobacco smoke (BrC-ETS) exposure was measured from the filters. We per-formed a multivariate analysis of woodstove presence and other factors that influenced PM2.5, BC, and BrC exposures. We collected valid exposure data from 258 of the 272 participants (95%). Children wore the MicroPEM for an average of 46% of the 72-h period, and over 80% for a 2-day, 1-night period (with sleep hours counted as non-compliance for this study). Elevated PM2.5 exposures oc-curred in the morning, evening, and overnight. Median PM2.5, BC, and BrC-ETS concentrations were 8.1 μg/m3, 3.6 μg/m3, and 2.4 μg/m3. The combined BC and BrC-ETS mass comprised 72% of the PM2.5. Woodstove presence, hours used per day, and the primary heating source were associated with the children’s PM2.5 exposure and air filters were associated with reduced PM2.5 concentrations. Our findings suggest that woodstove smoke contributed significantly to this cohort’s PM2.5 expo-sure. The high sample validity and compliance rate demonstrated that the MicroPEM can be worn by young children in epidemiologic studies to measure their PM2.5 exposure, inform interventions to reduce the exposures, and improve children’s health

A Facile Synthesis of (\u3cem\u3etert\u3c/em\u3e-alkoxy)amines

Tertiary alcohols react with stoichiometric BF3·Et2O and N-hydroxyphthalimide to yield N-alkoxyphthalimides. Subsequent hydrazinolyses afford the title compounds

The agenda-setting power of fake news: A big data analysis of the online media landscape from 2014 to 2016

The definitive publisher-authenticated version: "Chris J Vargo, Lei Guo, Michelle A Amazeen. 2017. "The agenda-setting power of fake news: A big data analysis of the online media landscape from 2014 to 2016." New Media & Society, Vol 20, Issue 5, pp. 2028 - 2049" is available online at: https://doi.org/10.1177/1461444817712086.This study examines the agenda-setting power of fake news and fact-checkers who fight them through a computational look at the online mediascape from 2014 to 2016. Although our study confirms that content from fake news websites is increasing, these sites do not exert excessive power. Instead, fake news has an intricately entwined relationship with online partisan media, both responding and setting its issue agenda. In 2016, partisan media appeared to be especially susceptible to the agendas of fake news, perhaps due to the election. Emerging news media are also responsive to the agendas of fake news, but to a lesser degree. Fake news coverage itself is diverging and becoming more autonomous topically. While fact-checkers are autonomous in their selection of issues to cover, they were not influential in determining the agenda of news media overall, and their influence appears to be declining, illustrating the difficulties fact-checkers face in disseminating their corrections

Fucosylation and protein glycosylation create functional receptors for cholera toxin

Cholera toxin (CT) enters and intoxicates host cells after binding cell surface receptors using its B subunit (CTB). The ganglioside (glycolipid) GM1 is thought to be the sole CT receptor; however, the mechanism by which CTB binding to GM1 mediates internalization of CT remains enigmatic. Here we report that CTB binds cell surface glycoproteins. Relative contributions of gangliosides and glycoproteins to CTB binding depend on cell type, and CTB binds primarily to glycoproteins in colonic epithelial cell lines. Using a metabolically incorporated photocrosslinking sugar, we identified one CTB-binding glycoprotein and demonstrated that the glycan portion of the molecule, not the protein, provides the CTB interaction motif. We further show that fucosylated structures promote CTB entry into a colonic epithelial cell line and subsequent host cell intoxication. CTB-binding fucosylated glycoproteins are present in normal human intestinal epithelia and could play a role in cholera. DOI: http://dx.doi.org/10.7554/eLife.09545.00