Akin I.,Sb Ankara Diskapi Yildirim Beyazit Education And Research Hospital |
Caner G.,SB |
Olgun L.,SB |
Guiraud J.,University Claude Bernard Lyon 1 |
And 15 more authors.
Cochlear Implants International | Year: 2012
Objectives: The aims of this study were to collect data on electrically evoked compound action potential (eCAP) and electrically evoked stapedius reflex thresholds (eSRT) in HiResolution TM cochlear implant (CI) users, and to explore the relationships between these objective measures and behavioural measures of comfort levels (M-levels). Methods: A prospective study on newly implanted subjects was designed. The eCAP was measured intraoperatively and at first fitting through neural response imaging (NRI), using the SoundWave TM fitting software. The eSRT was measured intra-operatively by visual monitoring of the stapes, using both singleelectrode stimulation and speech bursts (four electrodes stimulated at the same time). Measures of M-levels were performed according to standard clinical practice and collected at first fitting, 3 and 6 months of CI use. Results: One hundred seventeen subjects from 14 centres, all implanted unilaterally with a HiResolution CII Bionic Ear ® or HiRes 90K ®, were included in the study. Speech burst stimulation elicited a significantly higher eSRT success rate than single-electrode stimulation, 84 vs. 64% respectively. The NRI success rate was 81% intra-operatively, significantly increasing to 96% after 6 months. Fitting guidelines were defined on the basis of a single NRI measurement. Correlations, analysis of variance, and multiple regression analysis were applied to generate a predictive model for the M-levels. Discussion: Useful insights were produced into the behaviour of objective measures according to time, electrode location, and fitting parameters. They may usefully assist in programming the CI when no reliable feedback is obtained through standard behavioural procedures. © W.S. Maney & Son Ltd 2012.
Rengifo-Herrera J.A.,SB |
Solar Energy | Year: 2010
Nitrogen and sulfur co-doped and N-doped TiO2 anatase TKP 102 (Tayca) were prepared by manual grinding with thiourea and urea, respectively, and annealing at 400 °C. Both materials showed visible-light absorption as measured by Diffuse Reflectance Spectroscopy (DRS). Interstitial N-doping, anionic and cationic S-doping was found when the TiO2 was doped with thiourea while TiO2 doped with urea showed only the presence of interstitial N-doping as measured by X-ray Photo-electron Spectroscopy (XPS). The N content on the surface of N-doped TKP 102 photocatalyst was 2.85 at.% and higher than the N content in the N, S co-doped TiO2 photocatalyst (0.6 at.%). The photocatalytic activity of the doped catalysts was tested using phenol and Escherichia coli as chemical and biological targets, respectively, using N, S co-doped, N-doped TiO2, undoped Degussa P-25 and undoped TKP 102 powders under simulated solar light. It was found that undoped Degussa P-25 was the photocatalyst with the highest photocatalytic activity towards phenol oxidation and E. coli inactivation. N, S co-doped powders showed almost the same photocatalytic activity as undoped TKP 102 while N-doped TKP 102 was the less active photocatalyst probably due the N impurities on the TiO2 acting as recombination centers. © 2009 Elsevier Ltd. All rights reserved.
Rengifo-Herrera J.A.,SB |
Pierzchala K.,Ecole Polytechnique Federale de Lausanne |
Sienkiewicz A.,Ecole Polytechnique Federale de Lausanne |
Forro L.,Ecole Polytechnique Federale de Lausanne |
And 3 more authors.
Journal of Physical Chemistry C | Year: 2010
An efficient, visible light active, N, S-codoped TiO2-based photocatalyst was prepared by reacting thiourea with nanoparticulate anatase TiO2. Commercial anatase powders were manually ground with thiourea and annealed at 400 °C in two crucibles with different surface-to-volume ratios (S/V ) 20 and 1.5) to prepare two N, S-codoped TiO2 materials. The differentiated aeration conditions during the catalyst annealing on the crucibles allowed for different amounts of O2 to reach the catalyst surface. The first material, with S/V = 20, herein referred to as D-TKP 102-A, was clear beige colored. The second material, with S/V = 1.5, herein referred to as D-TKP 102-B, was darker and revealed a markedly lower efficiency in Escherichia coli inactivation. The D-TKP 102-A powder presented visible light absorption due to the nitrogen (N) and sulfur (S) doping. X-ray photoelectron spectroscopy signals for this catalyst were observed for N 1s peaks at binding energies of 399.2 and 400.7 eV due to interstitial N-doping or Ti-O-N species. The S 2p were due to SO4 -2 signals with BE >168 eV and signals at 162.8 and 167.2 eV due to anionic and cationic S-doping, respectively. By fast kinetic spectroscopy, the decay of the electron induced by pulsed light at λ = 450 nm (∼8 ns/laser pulse) was followed for the D-TKP 102-A catalyst. Undoped D-TKP 102 catalyst did not promote the electron in the visible range, and consequently no signal decay could be observed in the latter case. Low-temperature electron spin resonance measurements at 8 K provided evidence for electrons trapped in shallow traps, such as oxygen vacancies, Vo, induced by N, S doped on D-TKP 102-A. The ESR measurements implementing the reactive scavenging with singlet oxygen scavenger, TMP-OH, revealed the production of singlet oxygen (1O2). © 2010 American Chemical Society.