Much of the recent research on homogeneous alkane oxidation has focused on the use of transition metal catalysts. Here, we report that the electrophilic main-group cations thallium(III) and lead(IV) stoichiometrically oxidize methane, ethane, and propane, separately or as a one-pot mixture, to corresponding alcohol esters in trifluoroacetic acid solvent. Esters of methanol, ethanol, ethylene glycol, isopropanol, and propylene glycol are obtained with greater than 95% selectivity in concentrations up to 1.48 molar within 3 hours at 180°C. Experiment and theory support a mechanism involving electrophilic carbon-hydrogen bond activation to generate metal alkyl intermediates. We posit that the comparatively high reactivity of these d(10) main-group cations relative to transition metals stems from facile alkane coordination at vacant sites, enabled by the overall lability of the ligand sphere and the absence of ligand field stabilization energies in systems with filled d-orbitals.

This study compared dual-task visual RT and verbal RT measures of listening effort in the child population. Overall, verbal RTs appear more sensitive than dual-task visual RTs to the negative effects of SNR and hearing loss. The current findings extend the literature on listening effort in the pediatric population by demonstrating that, even for speech that is accurately recognized, school-age CHL show a greater processing speed decrement than their normal-hearing counterparts, a decrement that could have a negative impact on learning and academic achievement in the classroom.

Objectives The goal of this study was to evaluate how digital noise reduction (DNR) impacts listening effort and judgment of sound clarity in children with normal hearing. It was hypothesized that, when two DNR algorithms differing in signal-to-noise ratio (SNR) output are compared, the algorithm which provides the greatest improvement in overall output SNR will reduce listening effort and receive a better clarity rating from child listeners. A secondary goal was to evaluate the relation between the inversion method measurements and listening effort with DNR processing. Design Twenty-four children with normal hearing (ages 7-12 years) participated in a speech recognition task in which consonant-vowel-consonant nonwords were presented in broadband background noise. Test stimuli were recorded through two hearing aids with DNR-off and DNR-on at 0 dB and +5 dB input SNR. Stimuli were presented to listeners and verbal response time (VRT) and phoneme recognition scores were measured. The underlying assumption was that an increase in VRT reflects an in increase in listening effort. Children rated the sound clarity for each condition. The two commercially available HAs were chosen based on: 1) an inversion technique which was used to quantify the magnitude of change in SNR with the activation of DNR, and 2) a measure of magnitude-squared coherence which was used to ensure that DNR in both devices preserved the spectrum. Results One device provided a greater improvement in overall output SNR than the other. Both DNR algorithms resulted in minimal spectral distortion as measured using coherence. For both devices, VRT decreased for the DNR-on condition suggesting that listening effort decreased with DNR in both devices. Clarity ratings were also better in the DNR-on condition for both devices. The device showing the greatest improvement in output SNR with DNR engaged improved phoneme recognition scores. The magnitude of this improved phoneme recognition was not accurately predicted with measurements of output SNR. Measured output SNR varied in the ability to predict other outcomes. Conclusions Overall, results suggest that DNR effectively reduces listening effort and improves subjective clarity ratings in children with normal hearing but that these improvements are not necessarily related to the output SNR improvements or preserved speech spectra provided by the DNR.

Purpose The primary purposes of this study were to examine the effects of hearing loss and respondent type (self- vs. parent-proxy report) on subjective fatigue in children. We also examined associations between child-specific factors and fatigue ratings. Method Subjective fatigue was assessed using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (PedsQL-MFS; Varni, Burwinkle, Katz, Meeske, & Dickinson, 2002). We compared self- and parent-proxy ratings from 60 children with hearing loss (CHL) and 43 children with normal hearing (CNH). The children ranged in age from 6 to 12 years. Results School-age CHL experienced more overall and cognitive fatigue than CNH, although the differences were smaller than previously reported. Parent-proxy report was not strongly associated with child self-report, and parents tended to underestimate their child's fatigue, particularly sleep/rest fatigue. Language ability was also associated with subjective fatigue. For CHL and CNH, as language abilities increased, cognitive fatigue decreased. Conclusions School-age CHL experience more subjective fatigue than CNH. The poor association between parent-proxy and child reports suggests that the parent-proxy version of the PedsQL-MFS should not be used in isolation when assessing fatigue in school-age children. Future research should examine how language abilities may modulate fatigue and its potential academic consequences in CHL.