Apoptosis, rather than neurogenesis, induces significant hippocampal-dependent learning and memory impairment in chronic low Cd2+ exposure.

Cadmium (Cd), a ubiquitous toxic heavy metal, with the intractable trait of low degradation, can induce multiple organ damage. Whereas, far less is known about its neurotoxicity and the specific mechanism in the chronic low Cd exposure. To investigate the chronic neurotoxicity of Cd2+ , we traced its effects for up to 30 months in mice which were exposed to Cd2+ by drinking the mimicking Cd-polluted water. We found the toxicity of chronic Cd exposure was a process associated with the transition from autophagy to apoptosis, and the switch of autophagy-apoptosis was Cd dose-dependent with the threshold of [Cd2+ ] 0.04 mg/L. Furthermore, JNK was found to be a hub molecule orchestrated the switch of autophagy-apoptosis by interacting with Sirt1 and p53. At last, the hippocampus-dependent learning and memory was damaged by continuous neuron apoptosis rather than deficit of neurogenesis. Therefore, elucidation of the effect, process, and potential molecular mechanism of the chronic low Cd2+ exposure is important for controlling of the environmental-pollutant Cd.

Microstructure and electrochemical performance of 3D hierarchical porous graphene/polyaniline composites.

Porous graphene materials show outstanding performance in energy storage field due to their unique microstructure and properties. To construct 3D hierarchical porous graphene and combine with conductive polyaniline is an effective way to realize high energy density and good cycling stability. The interlamellar macroporous structure of 3D graphene was constructed by polystyrene (PS) microspheres and nickel foam as double templates. The mesoporous structure was etched in 3D macroporous graphene sheets by potassium hydroxide (KOH) chemical activation. And 3D hierarchical porous graphene (3D-hpGr) composited with polyaniline (PANI) by in situ chemical oxidative polymerization to obtain 3D-hpGr/PANI composites. The effect of the introduction of 3D-hpGr on microstructure, morphology and electrochemical performance of the composites was investigated. PANI nanowire arrays successfully decorate the surface of the 3D-hpGr sheets when the amount of 3D-hpGr reaches 40% (wt%). The specific capacitance of 3D-hpGr/PANI40 reaches 573 F g-1 at 0.5 A g-1, much higher than that of pure PANI (419 F g-1). The retention ratio of 3D-hpGr/PANI40 retains 84% of its initial specific capacitance after 1000 cycles at 1.0 A g-1, and the cycling stability of all composites is higher than that of pure PANI (69%). The potential drop of 3D-hpGr/PANI composites decreases from 0.339 V to 0.139 V, and the energy density increases consequently. The energy density of 3D-hpGr/PANI40 reaches 31.2 W h kg-1 at the power density of 0.709 kW kg-1.