Naturally occurring anthocyanin indicators
have been used for many
years to introduce science students to acid–base concepts.
A classroom activity has been developed that uses naturally occurring
anthocyanins to monitor the pH changes associated with the fermentation
of red cabbage to sauerkraut by lactic acid bacteria. Through the
activity and related discussion, students are introduced to the scientific
method, basic laboratory practices, acid–base chemistry, chemical
and physical changes, fermentation, and microbiology. Although this
activity and accompanying assignments are designed for students ages
6–12, the activity is adaptable to students of all ages and
backgrounds.
Elemental mercury (Hg 0 ) contamination in artisanal and small-scale gold mining (ASGM) communities is widespread, and Hg 0 -contaminated tailings are often reprocessed with cyanide ( − CN) to extract residual gold remaining after amalgamation. Hg 0 reacts with − CN under aerobic conditions to produce Hg(CN) 4 2− and other Hg(CN) n n−2 complexes. The production of solvated Hg(CN) n n−2 complexes increases upon agitation in the presence of synthetic and authentic Hg 0 -contaminated tailings that aid in dispersing the Hg 0 , increasing its reactive surface area. Adult rats were exposed to various concentrations of Hg(CN) 2 , and accumulation in organs and tissues was quantified using direct mercury analysis. The primary site of Hg(CN) 2 accumulation was the kidney, although accumulation was also detected in the liver, spleen, and blood. Little accumulation was observed in the brain, suggesting that Hg(CN) 2 complexes do not cross the blood−brain barrier. Renal tissue was particularly sensitive to the effects of Hg(CN) 2 , with pathological changes observed at low concentrations. Hg(CN) 2 complexes are handled by mammalian systems in a manner similar to other inorganic species of Hg, yet appear to be more toxic to organ systems. The findings from this study are the first to show that Hg(CN) 2 complexes are highly stable complexes that can lead to cellular injury and death in mammalian organ systems.
We present a case of an iris sphincter tear with iridodialysis, mydriasis, and hyphema secondary to a traumatic injury from a bungee cord. The correlation between the mechanism of injury and physical exam findings as well as the emergency department evaluation and management are discussed.
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