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Modulating the electronic structure of atomically dispersed active sites is promising to boost catalytic activity but is challenging to achieve. Here we show a cooperative Ni single‐atom‐on‐nanoparticle catalyst (NiSA/NP) prepared via direct solid‐state pyrolysis, where Ni nanoparticles donate electrons to Ni(i)−N−C sites via a network of carbon nanotubes, achieving a high CO current density of 346 mA cm−2 at −0.5 V vs RHE in an alkaline flow cell. When coupled with a NiFe‐based anode in a zero‐gap membrane electrolyzer, the catalyst delivers an industrially relevant CO current density of 310 mA cm−2 at a low cell voltage of −2.3 V, corresponding to an overall energy efficiency of 57 %. The superior CO2 electroreduction performance is attributed to the enhanced adsorption of key intermediate COOH* on the electron‐rich Ni single atoms, as well as a high density of active sites. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor (VEGF) had neuroprotective effects on dopaminergic (DA) neurons. In order to overcome the gastrointestinal digestion and bioaccessibility, VEGF was encapsulated with poly‐lactic‐co‐glycolic acid nanospheres (NS) in order to prevent the VEGF degradation until its release. The caudal administration of VEGF and NS encapsulated VEGF at different doses (1.0, 10.0, and 100.0 ng/ml) on the rats with Parkinson's disease lesion was evaluated. Intravenous injected VEGF at the dose of 1 ng/ml displayed the strongest neuroprotective effect than other groups as well as the stereotaxic group. The NS encapsulated with VEGF can pass through blood–brain barrier and protect the DA neurons. There was no significant difference between intravenous injection method and stereotaxic method, while the first method is simpler and convenient. Injection of NS encapsulated with VEGF may become a valuable neurorescuing therapeutic approach for Parkinson's disease. [ABSTRACT FROM AUTHOR]

Foam flooding is a promising technique for enhancing oil recovery, but the foam instability limits its application. This study investigates the properties of foam stabilized by silica (SiO2) nanoparticles combined with hexylamine. Surface dilational rheology, contact angle, and adsorption measurements have been performed and correlated with the foam stability. The results show that the SiO2/hexylamine dispersion induces a synergistic effect on the foam stability at intermediate hexylamine concentrations. The most stable foam was obtained with the most hydrophobic particles. The dilational viscoelasticity and the adsorption amount followed the same trend as that of foam stability. As a plugging agent, the SiO2/hexylamine foam could block the core with the maximum pressure peak at approximately 0.85 MPa. Moreover, our results indicate that the foam stability, dilational viscoelasticity, and roughness of the bubble surface together might contribute to better plugging performance in porous media. [ABSTRACT FROM AUTHOR]

Foam stabilized by a surfactant has been used successfully for mobility control during enhanced oil recovery processes, but the stability of the foam limits its application. Aqueous foams prepared from dispersions of partially hydrophobic silicon dioxide (SiO2) nanoparticles and sodium dodecyl sulfate (SDS) anionic surfactant were studied and the injection behavior of foams stabilized by a solution of SDS or dispersion of SiO2/SDS were analyzed for comparison. Foam stability increased with increasing nanoparticle concentration although the feasibility of producing a foam (foamability) followed the opposite trend. The surface tension and interfacial dilatational rheological properties were affected by the addition of SiO2 nanoparticles. When 0.05 wt % SiO2 was added to the solution of SDS, the system's dilatational elasticity increased significantly, but not the dilatational viscosity. The sweep efficiency to dead end was very small, and the SiO2/SDS foam could displace more residual oil in the dead end than that in the SDS foam. The differential pressure could increase to 0.58 MPa when SDS foam was injected, but for the SiO2/SDS foam it could increase to 1.7 MPa. The SiO2/SDS foam exhibited better profile control performance than that of the SDS foam. When subsequent water was injected for 3.5 pore volumes, the flow rate of the high-permeability sand pack could still be maintained at 1.0 mL min−1, which suggested that the SiO2/SDS foam had a better resistance to water flushing. Additionally, the foam volume should also be considered, especially for a SiO2 concentration of >1.5 wt %. SiO2/SDS foam can reduce the residual oil saturation clearly, and the enhanced oil recovery and final oil recovery can reach 36.90 and 69.57 %, respectively. [ABSTRACT FROM AUTHOR]

Recent studies suggest that dihydroartemisinin (DHA), a derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua L., has anticancer properties. Due to poor water solubility, poor oral activity, and a short plasma half-life, large doses of DHA have to be injected to achieve the necessary bioavailability. This study examined increasing DHA bioavailability by encapsulating DHA within gelatin (GEL) or hyaluronan (HA) nanoparticles via an electrostatic field system. Observations from transmission electron microscopy show that DHA in GEL and HA nanoparticles formed GEL/DHA and HA/DHA aggregates that were approximately 30-40 nm in diameter. The entrapment efficiencies for DHA were approximately 13 and 35% for the GEL/DHA and HA/DHA aggregates, respectively. The proliferation of A549 cells was inhibited by the GEL/DHA and HA/DHA aggregates. Fluorescent annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) staining displayed low background staining with annexin V-FITC or PI on DHA-untreated cells. In contrast, annexin V-FITC and PI stains dramatically increased when the cells were incubated with GEL/DHA and HA/DHA aggregates. These results suggest that DHA-aggregated GEL and HA nanoparticles exhibit higher anticancer proliferation activities than DHA alone in A549 cells most likely due to the greater aqueous dispersion after hydrophilic GEL or HA nanoparticles aggregation. These results demonstrate that DHA can aggregate with nanoparticles in an electrostatic field environment to form DHA nanosized aggregates. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 455-462, 2014. [ABSTRACT FROM AUTHOR]

Organic fluorescent dyes have attracted wide interest because of their high photoluminescence quantum efficiencies. However, there are several application limitations arising from their hydrophobicity, poor dispersity and large particle sizes. These problems can be improved by preparing nanoparticles with a small size. Herein, we present a continuous approach to efficiently prepare an aqueous nanodispersion of water‐insoluble organic fluorescent dye Nile red (NR) with monodispersed and uniform nanoparticles (35 nm) by high‐gravity antisolvent precipitation in a rotating packed bed (RPB). In contrast, NR nanodispersions prepared using a traditional batch stirred tank (ST) had a broad size distribution (20–150 nm). Due to its small size effect and good dispersity in water, the RPB nanodispersion displayed significantly increased saturation solubility and much stronger fluorescent intensity compared to raw NR, and was obviously superior to the ST counterpart. Furthermore, NR nanodispersions were mixed with ink to draw fluorescent patterns on paper for counterfeit labeling. [ABSTRACT FROM AUTHOR]