Quantitative crawling wave sonoelastography of benign and malignant thyroid nodules.

Objective: The purpose of this study is to determine if crawling wave elastography, a novel sonoelastography technique, can be used to provide quantitative measurements of thyroid tissue shear velocity (a measure of tissue stiffness) and distinguish between benign and malignant thyroid nodules.

Study Design: Diagnostic test assessment.

Setting: Academic university.

Dissecting the spatial scales of mercury accumulation in Ontario lake sediment.

Total mercury concentration was analyzed in 171 lakes from pre-industrial (>30 cm depth; Hg(pre-industrial)) and present-day sediments (0.5-1 cm; Hg(present-day)). Numerous hot or cold spots of sediment mercury enrichment (Hg EF; Hg(pre-industrial)/Hg(present-day)) were evident as determined by local tests of autocorrelation, although in most cases, the maximum correlation among sites was not the nearest neighbor, indicating a strong influence of watershed characteristics.

Temporal analysis of net fluvial methylmercury loading in a dystrophic and a clear water lake.

The concentration of methylmercury (MeHg) in aquatic ecosystems is the net result of the highly dynamic abiotic and biotic processes of mercury methylation and demethylation. In this study, we conduct an examination of the net fluvial loading of methylmercury (MeHg(Net)=MeHg(Watershed)-MeHg(Lake outflow)) across a 3 year time frame in both a dystrophic lake and an oligotrophic lake. A significant portion of MeHg(Net) variance in both lakes could be attributed to a seasonal pattern (11.