We screened for novel circuits in the mouse brain that promote wakefulness. Chemogenetic activation experiments and EEG recordings pointed to glutamatergic/nitrergic (NOS1) and GABAergic neurons in the VTA. Activating glutamatergic/NOS1 neurons, which were wake- and REM-sleep-active, produced wakefulness through projections to the nucleus accumbens and the lateral hypothalamus. Lesioning the glutamate cells impaired the consolidation of wakefulness. By contrast, activation of GABAergic VTA neurons elicited long-lasting NREM-like sleep resembling sedation. Lesioning these neurons produced an increase in wakefulness that persisted for at least 4 months. Surprisingly, these VTA GABAergic neurons were wake-and REM-sleep-active. We suggest that GABAergic VTA neurons may limit wakefulness by inhibiting the arousal-promoting VTA glutamatergic and/or dopaminergic neurons and through projections to the lateral hypothalamus. Thus, in addition to its contribution to goal- and reward-directed behaviours, the VTA has a role in regulating sleep and wakefulness.

Lipid incorporation from the ER to lipid droplets (LDs) influences LD growth and intracellular lipid homeostasis. Xu et al. identify Rab18 as an important regulator of LD dynamics: activated Rab18 binds to ER-associated proteins such as the NRZ complex and SNAREs. The Rab18-NRZ-SNARE complex tethers LDs to the ER, facilitating lipid incorporation and LD growth.

An efficient and selective four-electron plus four-proton (4e − ∕4H þ ) reduction of O 2 to water by decamethylferrocene and trifluoroacetic acid can be catalyzed by a synthetic analog of the heme a 3 ∕Cu B site in cytochrome c oxidase ( 6 LFeCu) or its Cu-free version ( 6 LFe) in acetone. A detailed mechanistic-kinetic study on the homogeneous catalytic system reveals spectroscopically detectable intermediates and that the rate-determining step changes from the O 2 -binding process at 25°C room temperature (RT) to the O-O bond cleavage of a newly observed Fe III -OOH species at lower temperature (−60°C). At RT, the rate of O 2 -binding to 6 LFeCu is significantly faster than that for 6 LFe, whereas the rates of the O-O bond cleavage of the Fe III -OOH species observed (−60°C) with either the 6 LFeCu or 6 LFe catalyst are nearly the same. Thus, the role of the Cu ion is to assist the heme and lead to faster O 2 -binding at RT. However, the proximate Cu ion has no effect on the O-O bond cleavage of the Fe III -OOH species at low temperature.heme/copper | dioxygen reduction | ferric hydroperoxo | kinetic mechanism | enzyme model

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The polymer-grafted magnetic composite particles have been synthesized and developed to harvest oil by use of their speical wettability. Different from gravity-driven oil-water separation, the prepared polymer brushes-grafted magnetic composite particles can act as solid-stabilizers that diffuse to the oil-water interfical region and effectively minimize the direct oil-water interfical area by volume exclusion, whereas the magnetic Fe3O4 core allows easy separation of Pickering emulsions from oil-water mixture under an external magnetic field. When the emulsions were heated from room temperature to 50 °C, the coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) acts as the driving force for the destabilization of the emulsion, thereby achieving the release of oil. The novel materials can be used in aspects of oil-water separation, inducing oil droplet transport and release of lipophilic substrates.