The aim of this study was to investigate whether uric acid (UA) might exert neuroprotection via activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and regulating neurotrophic factors in the cerebral cortices after transient focal cerebral ischemia/reperfusion (FCI/R) in rats. UA was intravenously injected through the tail vein (16 mg/kg) 30 min after the onset of reperfusion in rats subjected to middle cerebral artery occlusion for 2 h. Neurological deficit score was performed to analyze neurological function at 24 h after reperfusion. Terminal deoxynucleotidyl transferase-mediated dNTP nick end labeling (TUNEL) staining and hematoxylin and eosin (HE) staining were used to detect histological injury of the cerebral cortex. Malondialdehyde (MDA), the carbonyl groups, and 8-hydroxyl-2′-deoxyguanosine (8-OHdG) levels were employed to evaluate oxidative stress. Nrf2 and its downstream antioxidant protein, heme oxygenase- (HO-) 1,were detected by western blot. Nrf2 DNA-binding activity was observed using an ELISA-based measurement. Expressions of BDNF and NGF were analyzed by immunohistochemistry. Our results showed that UA treatment significantly suppressed FCI/R-induced oxidative stress, accompanied by attenuating neuronal damage, which subsequently decreased the infarct volume and neurological deficit. Further, the treatment of UA activated Nrf2 signaling pathway and upregulated BDNF and NGF expression levels. Interestingly, the aforementioned effects of UA were markedly inhibited by administration of brusatol, an inhibitor of Nrf2. Taken together, the antioxidant and neuroprotective effects afforded by UA treatment involved the modulation of Nrf2-mediated oxidative stress and regulation of BDNF and NGF expression levels. Thus, UA treatment could be of interest to prevent FCI/R injury.

Hybrid carbon films composed of graphene film and porous carbon film may give full play to the advantages of both carbon materials, and have great potential for application in energy storage and conversion devices. Unfortunately, there are very few reports on fabrication of hybrid carbon films. Here we demonstrate a simple approach to fabricate free-standing sandwich-structured hybrid carbon film composed of porous amorphous carbon film and multilayer graphene film by chemical vapor deposition in a controllable and scalable way. Hybrid carbon films reveal good electrical conductivity, excellent flexibility, and good compatibility with substrate. Supercapacitors assembled by hybrid carbon films exhibit ultrahigh rate capability, wide frequency range, good capacitance performance, and high-power density. Moreover, this approach may provide a general path for fabrication of hybrid carbon materials with different structures by using different metals with high carbon solubility, and greatly expands the application scope of carbon materials.

A new and simple approach is proposed for the first time to fabricate free-standing amorphous carbon films (FS-ACFs) with controllable thickness by ambient pressure chemical vapor deposition (APCVD). The approach uses methane as the carbon source and Ni foil as the catalytic substrate, in which a large number of carbon atoms are trapped by controlling the experimental conditions during the APCVD growth process, and FS-ACFs are obtained by a simple corrosion of the Ni foil after APCVD growth.FS-ACFs having a uniform and continuous morphology with variable sizes over one hundred square centimeters and a controllable thickness of tens to hundreds of nanometers are synthesized by controlling the experimental conditions. Microstructure observations show that FS-ACFs have porous and transparent characteristics, which can be transferred or bent on different substrates, thus allowing for a variety of potential applications in electrochemistry. As a proof of concept, an electrochemical supercapacitor device directly assembled by using the FS-ACF exhibits an ultrashort time constant of 46 ms, a wide frequency range ($kHz) for capacitive feature, and a good capacitance performance with an area specific capacitance of 0.28 mF cm À2 at a scan rate of 50 mV s À1 . Furthermore, the FS-ACF-based supercapacitor shows a high power density with a maximum volumetric power density of 17.76 W cm À3 .

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