Spotlights Cite This: J. Phys. Chem. Lett. 2018, 9, 4130−4130
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Spotlights: Volume 9, Issue 14
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IMPACTS OF LIPASE ENZYME ON THE SURFACE PROPERTIES OF MARINE AEROSOLS Sea spray is a pleasant part of any beach vacation, adding volume to your hair, scenting your towel, and slightly warping your beach read. Of course, the less-romantic term “marine aerosol” is used by the scientists who study the role that this mist plays in the Earth’s climate. Schiffer et al. (10.1021/ acs.jpclett.8b01363) used surface adsorption Langmuir isotherms combined with all-atom explicit solvent molecular dynamics simulations to illuminate how lipase enzymes affect the chemical structure of atmospheric sea spray aerosols (SSAs), and by extension their climate-relevant properties. Lipases convert triacylglycerols and phospholipids into fatty acids, a molecular species with varying surface activities and tensions. Thus, the activity of lipase could alter the physicochemical properties of SSA surfaces, which in turn guide the climate-relevant impacts of these aerosols. The authors report three main findings: (1) Negatively charged lipid bilayers elicit concerted fluctuations in triacylglycerol lipase residues that are tuned by changes in bilayer lipid composition, or surface pressure, increasing or decreasing lipase activity; (2) lipase is more conformationally or structurally dynamic in neutral bilayers than in negatively charged lipid bilayers; and (3) the more dynamic the atoms of lipase are, the more the lipase destabilizes neighboring lipids. The results reveal how electrostatic interactions, pH, and surface pressure alter the chemistry of protein-containing lipid environments and thus can alter surface characteristics of a marine aerosol-like environment. The authors also provide insight into the mechanism of lipase lid closure and the role of lipid charge on protein dynamics.
state or a slowly growing bubble at a predetermined location and performed in situ imaging and analysis of the bubble’s microlayer from its origination to its evolution. The results show that the liquid−solid interaction plays an important role in the microlayer’s origin and that strong interactions can lead to the formation of a bubble with a completely wetted base. The microlayer thickness decreases in time as the bubble grows, eventually forming the contact line. The authors also determined the mechanism and energy required for contact line and microlayer movement.
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ORIGIN, EVOLUTION, AND MOVEMENT OF MICROLAYER IN POOL BOILING To the nonscientist, the term “pool boiling” might sound like the stuff of nightmares or summertime horror movies. A boiling pool would be undesirable in any backyard; fortunately, pool boiling is not going to ruin your next party. It is simply a form of boiling caused by a heating element being immersed in stagnant liquid. Boiling is one of the most widely used processes to transfer heat across a surface, with wide-ranging applications, from residential refrigerators to industrial boilers to the International Space Station. In fact, most electricity generation in the United States is through the use of steam turbines, which require boilers, so improvements in boiling heat transfer efficiency will lead to energy and cost savings. Zou et al. (10.1021/acs.jpclett.8b01646) used pool boiling to study the origin and evolution of the microlayer, a thin, multiscale liquid film present underneath a vapor bubble. The authors conducted in situ visualization of microsized vapor bubbles and molecular dynamics simulations of bubble nucleation. Microlayer is of great importance in pool boiling because extremely high heat flux and reduced pressure occur there; thus, the microlayer governs the overall bubble growth behavior. The authors used laser heating to create a steady © 2018 American Chemical Society
Published: July 19, 2018 4130
DOI: 10.1021/acs.jpclett.8b02163 J. Phys. Chem. Lett. 2018, 9, 4130−4130
