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Hippocampal neurogenesis plays an important role in the onset and treatment of depressive disorders. Previous studies suggest that paeoniflorin could be used as an antidepressant for treating rats subjected to chronic unpredictable stress. In this study, the effects of paeoniflorin on neurogenesis in the hippocampus dentate gyrus and potential mechanism of action are further investigated in chronic unpredictable stress-induced rat. Results suggest that paeoniflorin markedly increased both sucrose consumption and the number of 5-bromo-2-deoxyuridine-positive cells in the dentate gyrus of chronic unpredictable stress-induced rats, and the ratio of co-expressed 5-bromo-2-deoxyuridine and glial fibrillary acidic protein-positive cells, but exerted no significant effect on the ratio of co-expressed 5-bromo-2-deoxyuridine and neuronal nuclei-positive cells. Compared with the vehicle group, a significant increase was detected in the number of brain-derived neurotrophic factor-positive cells and the expression of brain-derived neurotrophic factor mRNA in the hippocampus of the paeoniflorin-treated group. According to the results, paeoniflorin promoted neural stem cell proliferation, their differentiation into astrocytes, and neurogenesis in the hippocampal dentate gyrus of chronic unpredictable stress-induced rats. Apart from enhancing the protein expression and gene transcription of brain-derived neurotrophic factor, it also activated the expression of tropomyosin receptor kinase B (a high-affinity receptor of brain-derived neurotrophic factor). This suggests that paeoniflorin might promote neurogenesis in the hippocampus dentate gyrus of chronic unpredictable stress-induced rats and act as an antidepressant by regulating the brain-derived neurotrophic factor-tropomyosin receptor kinase B signaling pathway.

For promoting the preparation and application of graphene-based composite materials, graphene/nickel composite coating and pure nickel coating were prepared on the surface of carbon steel substrate by electrodeposition method. The morphology of coating was observed and analyzed by scanning electron microscope (SEM), and the phase of the coating was analyzed by X-ray diffractometer (XRD). The mechanical properties of the coating were evaluated by hardness tester. Results showed that the introduction of graphene refined the nickel based crystal grains for graphene/nickel composite coating under the same preparation conditions. Due to the higher conductivity of the graphene than the Ni, Ni ions tended to be preferably deposited on the surface of the graphene sheets during electrodeposition process, leading to formation of bumps, while pure Ni coating without graphene exhibited a smooth and flat surface and a coarse grain structure. XRD results showed that no phase transformation occurred during electrodeposition process, and the addition of graphene resulted in the smaller crystal grains and the denser surface microstructure of deposited Ni. Raman spectrum results indicated that the smaller the deposition current, the greater the intensity ratio of 2D peak to G peak of deposited graphene, and the better the dispersion effect. Moreover, the hardness of the nickel coating with graphene was significantly higher than that of the coating without graphene, and the highest hardness could reach about 530 HV4.9 N. The above results showed that the electrodeposition method could be an effective way to introduce graphene in the metal substrate as the second phase to prepare high-performance graphene/metal composite materials.

Numerosity perception is a process involving several stages of visual processing. This study investigated whether distinct mechanisms exist in numerosity adaptation under different awareness conditions to characterize how numerosity perception occurs at each stage. The status of awareness was controlled by masking conditions, in which monoptic and dichoptic masking were proposed to influence different levels of processing. Numerosity adaptation showed significant aftereffects when the participants were aware (monoptic masking) and unaware (dichoptic masking) of adaptors. The interocular transfer for numerosity adaptation was distinct under the different awareness conditions. Adaptation was primarily binocular when participants were aware of stimuli and was purely monocular when participants were unaware of adaptors. Moreover, numerosity adaptation was significantly reduced when the adaptor dots were clustered into chunks with awareness, whereas clustering had no effect on unaware adaptation. These results show that distinct mechanisms exist in numerosity processing under different awareness conditions. It is suggested that awareness is crucial to numerosity cognition. With awareness, grouping (by clustering) influences numerosity coding through altered object representations, which involves higher-level cognitive processing. [ABSTRACT FROM AUTHOR]