Arsenic speciation: HPLC followed by ICP-MS or INAA

Sensitivities for the measurement of four arsenic species, As^III, As^V, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), in environmental waters and rice extracts by a new neutron activation analysis (NAA) method using pre-separation of the species by liquid chromatography were determined. A manual fraction collection was used to isolate the species, followed by instrumental neutron activation analysis procedures. The sensitivities determined for arsenic species in the samples varied from 1.21 to 1.47 ng per vial or about 30 μg·L⁻¹ in sample solutions which translates to about 900 ng arsenic per gram of rice for our HPLC-NAA experiments.     

The Effect of Speaking Context on Elicitation of Habitual Pitch

The purpose of this study was to investigate if there was an effect of speaking context on the elicitation of habitual pitch [speaking fundamental frequency (SFF)]. Six simulated speaking contexts were created (speaking during a voice evaluation, speaking in public, speaking to a peer, speaking to a superior, speaking to a subordinate, and speaking to a parent or spouse), and the SFF for 30 adult women with normal voice was compared across these contexts. A one-way analysis of variance (ANOVA) revealed a statistically significant (P < 0.001) effect of simulated speaking context on SFF, with post hoc analyses indicating a statistically significant difference in SFF while "speaking to a superior" (P < 0.001) and "speaking to a subordinate" (P < 0.001). Possible reasons for an effect of speaking context are discussed. Also, the implications of the use of varied speaking contexts when eliciting SFF are discussed, as is the possibility of an effect of speaking context on the elicitation of other clinically useful voice parameters.