River phosphorus cycling during high flow may constrain Lake Erie cyanobacteria blooms.

Cyanobacterial harmful blooms have been increasing worldwide, due in part to excessive phosphorus (P) losses from agriculture-dominated watersheds. Unfortunately, cyanobacteria bloom management is often complicated by uncertainty associated with river P cycling. River P cycling mediates P exports during low flow but has been assumed to be unimportant during high flows.

Evolving management of HER2+ breast cancer brain metastases and leptomeningeal disease.

Patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer are at a particularly high risk of breast cancer brain metastasis (BCBM) and leptomeningeal disease (LMD). Improvements in systemic therapy have translated to improved survival for patients with HER2-positive BCBM and LMD. However, the optimal management of these cases is rapidly evolving and requires a multidisciplinary approach.

Recurrent High-Grade Invasive Mucoepidermoid Carcinoma of Larynx: A Case Report and Review of the Literature.

Recurrent invasive high-grade mucoepidermoid carcinoma of the larynx and hypopharynx is a rare occurrence. These tumors have been commonly associated with salivary gland tumors, most commonly the parotid gland. The patient usually presents with the following symptoms: hoarseness (if larynx is involved), or changes in voice character, sore throat, cough, odynophagia, dysphagia, otalgia, difficulty breathing, weight loss, lymphadenopathy.

Ecological succession among iron-oxidizing bacteria.

Despite over 125 years of study, the factors that dictate species dominance in neutrophilic iron-oxidizing bacterial (FeOB) communities remain unknown. In a freshwater wetland, we documented a clear ecological succession coupled with niche separation between the helical stalk-forming Gallionellales (for example, Gallionella ferruginea) and tubular sheath-forming Leptothrix ochracea. Changes in the iron-seep community were documented using microscopy and cultivation-independent methods.

Flow injection analysis of H2O2 in natural waters using acridinium ester chemiluminescence: method development and optimization using a kinetic model.

Chemiluminescence (CL) of acridinium esters (AE) has found widespread use in analytical chemistry. Using the mechanism of the reaction of H2O2 with 10-methyl-9-(p-formylphenyl)acridinium carboxylate trifluoromethanesulfonate and a modified flow injection system, the reaction rates of each step in the mechanism were evaluated and used in a kinetic model to optimize the analysis of H2O2. Operational parameters for a flow injection analysis system (reagent pH, flow rate, sample volume, PMT settings) were optimized using the kinetic model.

Carbon dioxide effects on luminol and 1,10-phenanthroline chemiluminescence.

Luminol and 1,10-phenanthroline are widely used chemiluminescent (CL) reagents for the analysis of a wide range of metals and inorganic and organic complexes. While the fundamental mechanism for luminol and 1,10-phenantholine chemiluminescence is understood, the analytical application of these reagents is largely empirical and often poorly described mechanistically. For example, CL signals observed from metal-luminol systems are strongly dependent on the pH of the sample, even though the final pH of the reaction mixture is controlled to a narrow range by a buffer.