BACKGROUND
The mesolimbic reward system plays a critical role in modulating nociception; however, its underlying molecular, cellular, and neural circuitry mechanisms remain unknown.
METHODS
Chronic constrictive injury (CCI) of the sciatic nerve was used to model neuropathic pain. Projection-specific in vitro recordings in mouse brain slices and in vivo recordings from anesthetized animals were used to measure firing of dopaminergic (DA) neurons in the ventral tegmental area (VTA). The role of VTA–nucleus accumbens (NAc) circuitry in nociceptive regulation was assessed using optogenetic and pharmacological manipulations, and the underlying molecular mechanisms were investigated by Western blotting, enzyme-linked immunosorbent assays, and conditional knockdown techniques.
RESULTS
c-Fos expression in and firing of contralateral VTA–NAc DA neurons were elevated in CCI mice, and optogenetic inhibition of these neurons reversed CCI-induced thermal hyperalgesia. CCI increased the expression of brain-derived neurotrophic factor (BDNF) protein but not mRNA in the contralateral NAc. This increase was reversed by pharmacological inhibition of VTA DA neuron activity, which induced an antinociceptive effect that was neutralized by injecting exogenous BDNF into the NAc. Moreover, inhibition of BDNF synthesis in the VTA with anisomycin or selective knockdown of BDNF in the VTA–NAc pathway were antinociceptive in CCI mice.
CONCLUSIONS
These results reveal a novel mechanism of nociceptive modulation in the mesolimbic reward circuitry and provide new insight into the neural circuits involved in the processing of nociceptive information.
Vertical sandwich-like architectures of Fe2P@rGO were constructed and performed well in terms of excellent HER activity and high stability simultaneously.
Photocatalytic nitrogen (N2) fixation suffers from low efficiency due to the difficult activation of the strongly nonpolar NN bond. In this study, a Ru–Co bimetal center is constructed at the interface of Ru/CoSx with S‐vacancy on graphitic carbon nitride nanosheets (Ru‐Vs‐CoS/CN). Upon adsorption, the two N atoms in N2 are bridged to the Ru–Co center, and the asymmetrical electron donation from Ru and Co atoms to N2 adsorbate highly polarized NN bond to double bond order. The plasmonic electric‐field‐enhancement effect enables the Ru/CoSx interface to boost the generation of energetic electrons. The Schottky barrier between Ru and CoSx endows the interface with electron transfer from CoSx to Ru. The Ru‐end bound N at the Ru–Co center is preferentially hydrogenated. As a result, the Ru‐Vs‐CoS/CN photocatalyst shows an NH3 production rate of up to 0.438 mmol g−1 h−1, reaching a high apparent quantum efficiency of 1.28% at 400 nm and solar‐to‐ammonia efficiency of 0.042% in pure water under AM1.5G light irradiation.
Thermal barrier coatings (TBCs) can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat. However, the continuous pursuit of a higher operating temperature leads to degradation, delamination, and premature failure of the top coat. Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems. In this paper, the latest progress of some new ceramic materials is first reviewed. Then, a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion. Finally, new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar, columnar, and nanostructure inclusions. The latest developments of ceramic top coat will be presented in terms of material selection, structural design, and failure mechanism, and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance, better thermal insulation, and longer lifetime.
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