Singing requires exquisite coordination between the respiratory and phonatory systems to efficiently control glottal airflow. Asymptomatic singing students underwent pulmonary function testing (PFT), videostrobolaryngoscopic examination, and measures of glottal efficiency (maximum phonation time [MPT], glottal flow rate [GFR], and phonation quotient [PQ]) performed in both a sung and spoken tone. Pulmonary function and glottal efficiency values were within reported normative data for professional singers. However, sung tones were made with significantly higher GFR and PQ and lower PQ than spoken tones. The mean GFR was not related to the degree of glottal closure (by videostrobolaryngoscopy) or underlying pulmonary support. 相似文献
The photopolymerization of acrylated oligomers dispersed in an aqueous medium is successfully demonstrated using a simple continuous photoreactor designed with flexible tubing, which presents straightforward up‐scaling and maintenance features. The performance of the continuous photoreactor is assessed by varying the length of the tube exposed to ultraviolet light as well as the flow rate of the aqueous dispersion thr ough the reactor. The insoluble nature of the dispersed particles after in‐situ photo‐crosslinking is particularly suitable for the estimation of the actual number of polymerized particles from static and dynamic light scattering data. The procedure is discussed in detail. Along with the overall acrylate double bond conversion of the particles determined by infrared spectroscopy, an estimation of the average conversion per polymerized particle is provided as a function of the exposure time to ultraviolet light. The sub‐microscopic characterization by peak‐force tapping atomic force microscopy of the particles after photopolymerization is also presented.
