The photochemistry of 2-phenylselenophene and 2-phenyltellurophene

2-Phenylselenophene is found to yield a mixture of 3-phenylselenophene, phenylvinylacetylene (PVA) and selenium upon irradiation. Photolysis of 2-phenyltellurophene produces only PVA and tellurium. Deuterium labeling studies revealed that PVA did not arise from a unimolecular reaction but involved hydrogen abstraction from solvent. These results are interpreted within an extension of van Tamelen's general mechanism for the photochemistry of aromatic heterocyclopentadienes.     

Disentangling the effects of phonation and articulation: Hemispheric asymmetries in the auditory N1m response of the human brain

Background  

The cortical activity underlying the perception of vowel identity has typically been addressed by manipulating the first and second formant frequency (F1 & F2) of the speech stimuli. These two values, originating from articulation, are already sufficient for the phonetic characterization of vowel category. In the present study, we investigated how the spectral cues caused by articulation are reflected in cortical speech processing when combined with phonation, the other major part of speech production manifested as the fundamental frequency (F0) and its harmonic integer multiples. To study the combined effects of articulation and phonation we presented vowels with either high (/a/) or low (/u/) formant frequencies which were driven by three different types of excitation: a natural periodic pulseform reflecting the vibration of the vocal folds, an aperiodic noise excitation, or a tonal waveform. The auditory N1m response was recorded with whole-head magnetoencephalography (MEG) from ten human subjects in order to resolve whether brain events reflecting articulation and phonation are specific to the left or right hemisphere of the human brain.