Detection and Classification of Ignitable Liquid Residues in the Presence of Matrix Interferences by Using Direct Analysis in Real Time Mass Spectrometry.

Conventional Gas Chromatography-Mass Spectrometry (GC-MS) methods for the analysis of ignitable liquids (ILs) are usually time-consuming, and the data produced are difficult to interpret. A fast IL screening method using direct analysis in real time mass spectrometry (DART-MS) is proposed in this study. GC-MS, QuickStrip DART-MS, and thermal desorption DART-MS methods were used to analyze neat ILs and thermal desorption DART-MS without extraction was used to analyze ILs on five substrates (e.

A Watershed Analysis of Seasonal Concentration- and Loading-based Results for Escherichia coli in Inland Waters.

Fecal indicator bacteria, such as Escherichia coli, are frequently monitored in recreational waterbodies as indicators of potential fecal pathogen presence and exposure. The present watershed analysis investigated the influence of season on E. coli concentration (MPN/100 mL) and loading (MPN/day) measurements for inland waters at baseflow conditions.

Effects of Maternally-Transferred Methylmercury on Stress Physiology in Northern Water Snake (Nerodia sipedon) Neonates.

Biomagnification of methylmercury in aquatic systems can cause elevated tissue mercury (Hg) and physiological stress in top predators. Mercury is known to affect stress hormone levels in mammals, birds and fish. In this study, the effects of maternally-transferred methylmercury on the stress physiology of Northern Water Snake (Nerodia sipedon) neonates were tested.

The use of tetragnathid spiders as bioindicators of metal exposure at a coal ash spill site.

On 22 December 2008, a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Fuel Plant (TN, USA) failed, resulting in the largest coal ash spill in US history. The present study was designed to determine sediment metal concentrations at multiple site locations and to determine whether site-specific bioaccumulation of metals existed in tetragnathid spiders. Selenium and nickel were the only 2 metals to exceed the US Environmental Protection Agency sediment screening levels.

Trophic status and metal bioaccumulation differences in multiple fish species exposed to coal ash-associated metals.

On December 22, 2008 a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Plant near Kingston Tennessee USA failed and resulted in the largest coal ash spill in U.S. history.

Effects of silver nanoparticles on zebrafish (Danio rerio) and Escherichia coli (ATCC 25922): a comparison of toxicity based on total surface area versus mass concentration of particles in a model eukaryotic and prokaryotic system.

Silver nanoparticles (Ag NPs) have been classified as the most abundant NP found in commercial products. In the present study, zebrafish (Danio rerio) and bacteria (Escherichia coli; ATCC 25922) were used to test the size-dependent toxicological effects of Ag NPs, the effects of ionic silver versus Ag NPs, and Ag NP effects on mortality using mass concentration (mg/L) compared with total surface area (nm(2) /L). Several diameters of Ag NPs (20, 50, 110 nm) as well as AgNO(3) were chosen as experimental treatments.

Mercury speciation and biomagnification in the food web of Caddo Lake, Texas and Louisiana, USA, a subtropical freshwater ecosystem.

We studied the biomagnification of total mercury and methylmercury in a subtropical freshwater lake, Caddo Lake, Texas and Louisiana, USA. The present study is unique in that it not only included invertebrates (seven species) and fish (six species) but also an amphibian (one species), reptiles (three species), and mammals (three species). Nonfish vertebrates such as those included in the present study are often not included in assessments of trophic transfer of Hg.

Asparagine362 is essential for zinc binding and catalysis in the peptidase reaction of Saccharomyces cerevisiae leukotriene A₄ hydrolase.

Zinc metallopeptidases are ubiquitous enzymes with diverse cellular functions that can be found in most organisms. Leukotriene A₄ hydrolase (LTA4H; E.C.