Rapid Screening and Quantification of PFAS Enabled by SPME-DART-MS.

Per- and polyfluoroalkyl substances (PFAS), an emerging class of toxic anthropogenic chemicals persistent in the environment, are currently regulated at the low part-per-trillion level worldwide in drinking water. Quantification and screening of these compounds currently rely primarily on liquid chromatography hyphenated to mass spectrometry (LC-MS). The growing need for quicker and more robust analysis in routine monitoring has been, in many ways, spearheaded by the advent of direct ambient mass spectrometry (AMS) technologies.

Calcium-Ion Binding Mediates the Reversible Interconversion of Cis and Trans Peroxido Dicopper Cores.

Coupled dinuclear copper oxygen cores (Cu O ) featured in type III copper proteins (hemocyanin, tyrosinase, catechol oxidase) are vital for O transport and substrate oxidation in many organisms. μ-1,2-cis peroxido dicopper cores ( P) have been proposed as key structures in the early stages of O binding in these proteins; their reversible isomerization to other Cu O cores are directly relevant to enzyme function. Despite the relevance of such species to type III copper proteins and the broader interest in the properties and reactivity of bimetallic P cores in biological and synthetic systems, the properties and reactivity of P Cu O species remain largely unexplored.

Grand challenges in the nitrogen cycle.

In this Viewpoint, we address some of the limitations within our current understanding of the complex chemistry of the enzymes used in the Nitrogen Cycle. Further understanding of these chemical processes will play a large role in limiting the anthropogenic effects on our environment.

COVID-19, Personal Protective Equipment, and Human Performance.

Clinicians who care for patients infected with coronavirus disease 2019 (COVID-19) must wear a full suite of personal protective equipment, including an N95 mask or powered air purifying respirator, eye protection, a fluid-impermeable gown, and gloves. This combination of personal protective equipment may cause increased work of breathing, reduced field of vision, muffled speech, difficulty hearing, and heat stress. These effects are not caused by individual weakness; they are normal and expected reactions that any person will have when exposed to an unusual environment.