2002-2017 anthropogenic emissions data for air quality modeling over the United States.

The United States Environmental Protection Agency (US EPA) has developed a set of annual North American emissions data for multiple air pollutants across 18 broad source categories for 2002 through 2017. The sixteen new annual emissions inventories were developed using consistent input data and methods across all years. When a consistent method or tool was not available for a source category, emissions were estimated by scaling data from the EPA's 2017 National Emissions Inventory with scaling factors based on activity data and/or emissions control information.

A reinterpretation of neutron scattering experiments on a lipidated Ras peptide using replica exchange molecular dynamics.

The Ras family of proteins plays crucial roles in a variety of cell signaling networks where they have the function of a molecular switch. Their particular medical relevance arises from mutations in these proteins that are implicated in ~30% of human cancers. The various Ras proteins exhibit a high degree of homology in their soluble domains but extremely high variability in the membrane anchoring regions that are crucial for protein function and are the focus of this study.

Backbone conformational flexibility of the lipid modified membrane anchor of the human N-Ras protein investigated by solid-state NMR and molecular dynamics simulation.

The lipid modified human N-Ras protein, implicated in human cancer development, is of particular interest due to its membrane anchor that determines the activity and subcellular location of the protein. Previous solid-state NMR investigations indicated that this membrane anchor is highly dynamic, which may be indicative of backbone conformational flexibility. This article aims to address if a dynamic exchange between three structural models exist that had been determined previously.

Molecular dynamics simulation study of correlated motions in phospholipid bilayer membranes.

A 100 ns simulation of a fluid phase dioleoylphosphatidylcholine bilayer, consisting of 288 lipid molecules at full hydration, has been studied to describe in detail the lateral translational motion of individual lipid molecules. Analysis of the simulation trajectories suggests that correlated motion between neighboring lipid molecules is an important aspect of lipid dynamics. The correlation among neighboring lipids within a monolayer is substantial and surprisingly long-ranged with a decay length of approximately 25 A.

Structure and dynamics of a fluid phase bilayer on a solid support as observed by a molecular dynamics computer simulation.

Simulations of a 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine lipid bilayer interacting with a solid surface of hydroxylated nanoporous amorphous silica have been carried out over a range of lipid-solid substrate distances. The porous solid surface allowed the water layer to dynamically adjust its thickness, maintaining equal pressures above and below the membrane bilayer. Qualitative estimates of the force between the surfaces leads to an estimated lipid-silicon distance in very good agreement with the results of neutron scattering experiments.