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The cathodic stripping of Te in CH 2 Cl 2 with 0.1 M [N n Bu 4 ]Cl has been studied. In background electrolyte the cathodic stripping of Te behaves in the expected way. In contrast, when the stripping occurs in the [N n Bu 4 ] 2 [TeCl 6 ] plating solution, unusual voltammetry is observed. Microelectrode and EQCM studies show that cathodic stripping of Te in the plating solution occurs with the passage of very little charge and leads to the formation of Te(0) in solution due to a rapid reaction between the reduced Te(-II) species and the Te(IV) salt. As a result, the limiting current for reduction of the Te(IV) is unchanged with 4 electron reduction leading to the formation of Te(0) on the electrode at potentials positive of the Te cathodic stripping potential and Te(0) in solution at potentials negative of the Te cathodic stripping potential. The same behaviour is found when a Te(II) precursor is used in place of the Te(IV) salt. [ABSTRACT FROM AUTHOR]

Electrodeposition of elemental Te from [N n Bu 4 ] 2 [TeCl 6 ] in a weakly coordinating solvent, dichloromethane, has been investigated. The reduction of the Te(IV) complex to deposit Te shows a very large (> 1 V) overpotential on clean Pt macrodisc electrodes and microelectrodes that is significantly reduced once Te has been deposited on the electrode. Corresponding studies show that there is no significant overpotential for the deposition of Te from the Te(II) complex, [NEt 4 ] 2 [T e I 4 ], under the same conditions, suggesting that the barrier for electrodeposition from [TeCl 6 ]2− arises because of the instability of the intermediate Te(III) species. Density functional theory (DFT) calculations with the M06–2X density functional and treatment of solvation using the polarizable continuum model confirm that the possible Te(III) complexes, [TeCl 5 ]2−, [TeCl 4 ]− and [TeCl 3 ], are all unstable with respect to disproportionation, confirming that the Te(III) intermediate is a thermodynamic barrier to the electrodeposition of Te(0) from [TeCl 6 ]2−. We propose that this thermodynamic barrier is overcome for the reaction at the Te electrode surface by a catalytic mechanism in which the transient Lewis acidic [TeCl 5 ]− complex forms a Lewis acid/base adduct ([TeCl 5 ]− —Te surface) through p-orbital overlap with the Te on the electrode surface. This mechanism is shown to be consistent with the results of DFT calculations for the speciation equilibria for the Te(IV) chloride complexes and with the results of experiments at different chloride concentration. Our results suggest that Lewis acid/base adduct formation at the electrode surface may also play a role in electrodeposition of other p-block elements. [ABSTRACT FROM AUTHOR]

Electrochemical impedance measurements were made in the single supercritical phase of CO 2 with 11 wt% acetonitrile as the co-solvent at temperatures and pressures between 306 and 316 K and 15.5 and 20.2 MPa over the potential range from −0.45 to +0.75 V vs. Pt. Gold, platinum and glassy carbon electrodes were studied together with the effects of electrolyte concentration for [NBu 4 n ][BF 4 ]. Two other electrolytes, [NBu 4 n ][B{3,5-C 6 H 3 (CF 3 ) 2 } 4 ] and [NMe 4 ][BF 4 ], were also studied. We find that the impedance data can be described by a simple RC equivalent circuit where the uncompensated solution resistance is independent of the electrode potential and is consistent with earlier measurements for the electrolyte conductivity. The results for the double layer capacitance can be described by a simple Helmholtz layer model and are very similar to those found for similar electrolytes in non-aqueous solvents such as propylene carbonate. For glassy carbon the double layer capacitances show a parabolic like potential dependence which we attribute to the lower density of states near the Fermi level. [ABSTRACT FROM AUTHOR]

Abstract: Background: British Columbia (BC) introduced a school-based HPV vaccine program in September 2008. As part of the HPV vaccine program evaluation, we determined the type-specific HPV prevalence in a population-based sample of women presenting for routine cervical cancer screening in the province. Methods: From June 2010 to February 2011, a total of 1100 physicians from all health regions in BC were invited to return ten sequential cytobrushes used during routine office-based Pap screening to the Provincial Health Services Authority Laboratories for HPV type-specific testing. Client age was the only identifier provided. Specimens were screened by the Digene Hybrid Capture® 2 High-Risk (hr) HPV DNA Test (HC2). HC2 positive specimens were then genotyped using the Roche cobas® 4800 HPV Test, the Roche Linear Array (LA) HPV Genotyping Test and the Digene® HPV Genotyping LQ Test. Results: Overall, 12.2% of the 4330 specimens with valid HC2 results were hrHPV positive. Age range was 15–69 (median 39.0). By age group, the proportion HC2 hrHPV positive was: 15–19, 25.7%; 20–24, 33.2%; 25–29, 21.9%; 30–34, 12.6%; 35–39, 9.5%; 40–44, 8.4%; ≥45, 3.4%. Overall hrHPV prevalence was 10.1% by Roche cobas® 4800, 10.5% by Roche LA and 10.3% by Digene LQ. For HPV 16/18, rates by age group by Roche LA were: 15–19, 5.1%/2.8%; 20–24, 9.5%/3.9%; 25–29, 6.2%/1.0%; 30–34, 2.4%/1.7%; 35–39, 1.2%/1.0%; 40–44, 1.6%/0.2%; ≥45, 0.3%/0.2%. Similar HPV 16/18 rates were obtained with the Digene LQ and Roche cobas® 4800 methods. Agreement between the three genotyping methods for HPV 16 and 18 was high. Conclusions: Comparable to other evaluations, hrHPV positivity was highest among younger women and HPV 16 was the most frequent genotype detected. These baseline estimates will be useful for monitoring the effectiveness of the HPV vaccine in BC. Type-specific analyses repeated at regular intervals over time may determine whether the use of HPV vaccine results in hrHPV genotype replacement in the province. [Copyright &y& Elsevier]

Investigates the nutrient contribution of vegetables to the diets of individuals by using the food grouping system (FGS) of the Human Nutrition Information Service. Application of the FGS to data from the 1987-1988 nationwide food consumption survey; Vegetable content of six categories of mixed foods; Comparison of FGS values to the values derived from traditional methods.

Presents several letters on medical practices in Great Britain. Management of asymptomatic hepatitis C infection; Discussions on the sexual transmission of hepatitis C; Assessment of the community care services.