Facile fabrication of 3D Janus foams of electrospun cellulose nanofibers/rGO for high efficiency solar interface evaporation.

Solar-powered interfacial evaporation is one of the most efficient state-of-the-art technologies for producing clean water via desalination. Herein, we report a novel bio-based nanofibrous foam for high efficiency solar interface evaporation. To this end, a hybrid membrane of cellulose nanofibers/graphene oxide (GO) is first fabricated by electrospinning coupled with in situ layer-by-layer self-assembly technique. After that, the membrane is subjected to a foaming process in an aqueous NaBH4, which effectively transforms the 2D membrane into a 3D foam. This structure can improve the photothermal conversion efficiency and also facilitate the water transport at the gas-water interface. In the meantime, the GO is converted to the reduced GO (rGO) with a higher light absorption efficiency. Finally, one side of the foam is hydrophobically modified via spray-coating with a fluorocarbon resin (FR) to obtain the Janus type 3D foam, namely FR@EC/rGO. The resultant 3D foam combines the functions of solar energy absorption in the upper layer and water pumping capability in the lower layer. It exhibits an extraordinary solar vapor conversion efficiency of 94.2 % and a fast evaporation rate of 1.83 kg m-2 h-1, showing high potential in future seawater desalination.

Brain-Derived Neurotrophic Factor Regulates Differentiation of Stem Cells From Human Exfoliated Deciduous Teeth Through Growth Factor Receptor-Bound Protein 2-Extracellular Signal-Regulated Kinase Signaling Pathway.

OBJECTIVES: Stem cells from human exfoliated deciduous teeth are a population of multipotent mesenchymal stem cells that can self-renew and actively secrete a broad spectrum of trophic and immunomodulatory factors.Brain-derivedneurotrophic factor is able to induce stem cells to neural differentiation to repair the nervous system. However,the mechanism ofbrain-derivedneurotrophic factor-induced neural differentiation in stem cells from human exfoliated deciduous teeth remains unclear. MATERIALS AND METHODS: In this study, we focused on brain-derived neurotrophic factor and investigated its effects on neural differentiation in stem cells from human exfoliated deciduous teeth. We cultured stem cells from human exfoliated deciduous teeth under various different brain-derived neurotrophic factor concentrations. We then analyzed the effects of brain-derived neurotrophic factor to the neural differen-tiation and associated signaling pathways in stem cells from human exfoliated deciduous teeth. RESULTS: We demonstrated that a high concentration of brain-derived neurotrophic factor could induce neural differentiation in stem cells from human exfoliated deciduous teeth, and brain-derived neurotrophic factor also increased the expression levels of neural differentiation-related proteins in stem cells from human exfoliated deciduous teeth, which was associated with the suppression of growth factor receptor-bound protein 2/extracellular signal-regulated kinase 1 and 2 signaling pathways. CONCLUSIONS: Knockdown of growth factor receptor- bound protein 2 inhibited the neural differentiation of stem cells from human exfoliated deciduous teeth via changes in growth factor receptor-bound protein 2/extracellular signal-regulated kinase signaling pathways, but this phenotype could be rescued by overexpression of extracellular signal-regulated kinase. Our findings suggested that brain-derived neurotrophic factor can regulate the differentiation of stem cells from human exfoliated deciduous teeth through the growth factor receptor-bound protein 2/extracellular signal-regulated kinase signaling pathway.

A novel PET tracer 18F-deoxy-thiamine: synthesis, metabolic kinetics, and evaluation on cerebral thiamine metabolism status.

BACKGROUND: Some neuropsychological diseases are associated with abnormal thiamine metabolism, including Korsakoff-Wernicke syndrome and Alzheimer's disease. However, in vivo detection of the status of brain thiamine metabolism is still unavailable and needs to be developed. METHODS: A novel PET tracer of 18F-deoxy-thiamine was synthesized using an automated module via a two-step route. The main quality control parameters, such as specific activity and radiochemical purity, were evaluated by high-performance liquid chromatography (HPLC). Radiochemical concentration was determined by radioactivity calibrator. Metabolic kinetics and the level of 18F-deoxy-thiamine in brains of mice and marmosets were studied by micro-positron emission tomography/computed tomography (PET/CT). In vivo stability, renal excretion rate, and biodistribution of 18F-deoxy-thiamine in the mice were assayed using HPLC and γ-counter, respectively. Also, the correlation between the retention of cerebral 18F-deoxy-thiamine in 60 min after injection as represented by the area under the curve (AUC) and blood thiamine levels was investigated. RESULTS: The 18F-deoxy-thiamine was stable both in vitro and in vivo. The uptake and clearance of 18F-deoxy-thiamine were quick in the mice. It reached the max standard uptake value (SUVmax) of 4.61 ± 0.53 in the liver within 1 min, 18.67 ± 7.04 in the kidney within half a minute. The SUV dropped to 0.72 ± 0.05 and 0.77 ± 0.35 after 60 min of injection in the liver and kidney, respectively. After injection, kidney, liver, and pancreas exhibited high accumulation level of 18F-deoxy-thiamine, while brain, muscle, fat, and gonad showed low accumulation concentration, consistent with previous reports on thiamine distribution in mice. Within 90 min after injection, the level of 18F-deoxy-thiamine in the brain of C57BL/6 mice with thiamine deficiency (TD) was 1.9 times higher than that in control mice, and was 3.1 times higher in ICR mice with TD than that in control mice. The AUC of the tracer in the brain of marmosets within 60 min was 29.33 ± 5.15 and negatively correlated with blood thiamine diphosphate levels (r = - 0.985, p = 0.015). CONCLUSION: The 18F-deoxy-thiamine meets the requirements for ideal PET tracer for in vivo detecting the status of cerebral thiamine metabolism.