Efficient and Selective CO2 Reduction to Formate on Pd-Doped Pb3 (CO3 )2 (OH)2 : Dynamic Catalyst Reconstruction and Accelerated CO2 Protonation.

Exploring catalyst reconstruction under the electrochemical condition is critical to understanding the catalyst structure-activity relationship as well as to design effective electrocatalysts. Herein, a PbF2 nanocluster is synthesized and its self-reconstruction under the CO2 reduction condition is investigated. F- leaching, CO2 -saturated environment, and application of a cathodic potential induce self-reconstruction of PbF2 to Pb3 (CO3 )2 (OH)2 , which effectively catalyze the CO2 reduction to formate. The in situ formed Pb3 (CO3 )2 (OH)2 discloses >80% formate Faradaic efficiencies (FEs) across a broad range of potentials and achieves a maximum formate FE of ≈90.1% at -1.2 V versus reversible hydrogen electrode (RHE). Kinetic studies show that the CO2 reduction reaction (CO2 RR) on the Pb3 (CO3 )2 (OH)2 is rate-limited at the CO2 protonation step, in which proton is supplied by bicarbonate (HCO3 - ) in the electrolyte. To improve the CO2 RR kinetics, the Pb3 (CO3 )2 (OH)2 is further doped with Pd (4 wt%) to enhance its HCO3 - adsorption, which leads to accelerated protonation of CO2 . Therefore, the Pd-Pb3 (CO3 )2 (OH)2 (4 wt%) reveals higher formate FEs of >90% from -0.8 to -1.2 V versus RHE and reaches a maximum formate FE of 96.5% at -1.2 V versus RHE with a current density of ≈13 mA cm-2 .

Hand gesture monitoring using fiber-optic curvature sensors.

A hand gesture monitoring system based on fiber-optic curvature sensors is developed. A glove is used as a carrier to support the monitoring system. According to the freedom of the hand joint, the layout of the sensors is established. An untreated fiber is introduced as a reference signal. The division operation between the sensing signal and reference signal is regarded as the monitoring result, which can reduce the monitoring error produced by external unstable factors. The experimental results show that the measurement errors are within the range of ±π/36 and ±π/75, respectively, when measuring the joint bending and abduction angle, which indicates the feasibility of the proposed monitoring system.

[Effects of Artesunate Combined with Arsenious Acid on Proliferation and Apoptosis of Multiple Myeloma Cells via PI3K/AKT Signaling Pathway].

OBJECTIVE: To investigate the effect of artesunate and arsenous acid and their combination on the proliferation and apoptosis of human multiple myeloma cells and their mechanism. METHODS: Human multiple myeloma cell line RPMI 8226 cells were cultured and treated with 0, 1, 2, 4, 8 nmol/L arsenous acid and 0, 40, 80, 160, 320 µmol/L artesunate, respectively. The inhibition of cell growth was detected by CCK-8 assay. The apoptosis rate was detected by flow cytometry. QPCR was used to detect the mRNA expression of cell proliferation and apoptosis-related factors. The expression of cell proliferation, apoptosis-related factors and PI3K/AKT pathway protein were detected by Western blot. RESULTS: CCK-8 assay showed that the growth of multiple myeloma cells was inhibited by arsenous acid and artesunate. The IC50 of arsenous acid was 1.96 nmol/L, and artesunate was 153.96 µmol/L. Flow cytometry showed that arsenous acid, artesunate, and their combination could significantly increase the apoptosis of multiple myeloma cells. QPCR and Western blot showed that the arsenous acid, artesunate, and their combination treatment could inhibit the expression of mRNA and protein of cell proliferation-related factors interleukin-6 and vascular endothelial growth factor (P<0.05), inhibit apoptosis-related factor BCL-xl and promote the expression of mRNA and protein of Bax (P<0.05), and reduce the protein expression of p-PI3K and p-AKT in PI3K/AKT signaling pathway (P<0.05). Moreover, the combination effect of the two drugs on cell apoptosis and the above mentioned factors was obviously stronger than that of the two drugs alone. CONCLUSION: Artesunate combined with arsenous acid inhibits proliferation and promotes apoptosis of tumor cells through PI3K/AKT signaling pathway, and is superior to the effect of two drugs alone.

Photocatalytic water reduction and study of the formation of Fe(i)Fe(0) species in diiron catalyst systems.

Noble-metal-free systems with bio-inspired diiron dithiolate mimics of the [FeFe]-hydrogenase active site, namely, [(µ-pdt)Fe(2) (CO)(5) L] [pdt=propanedithiolate; L=P(CH(2) OH)(3) (1), P(CH(3) )(3) (2)], as water reduction catalysts with xanthene dyes as photosensitizers and triethylamine as a sacrificial electron donor were studied for visible-light-driven water reduction to hydrogen. These systems display good catalytic activities with the efficiencies in hydrogen evolution of up to 226 turnovers for 1, if Eosin Y was used as the photosensitizer in an environmentally benign solvent (EtOH/H(2) O) after 15 h of irradiation (λ>450 nm) under optimal conditions. Under all of the conditions adopted, 1 that has a water soluble phosphine ligand, P(CH(2) OH)(3) displayed a higher efficiency than 2, which bears a PMe(3) ligand. The photoinduced electron transfer in the systems was studied using fluorescence, transient absorption, time-resolved UV/Vis, and in situ electron paramagnetic resonance (EPR) spectroscopy. A new electron-transfer mechanism is proposed for hydrogen evolution by these iron-based photocatalytic systems.

Photochemical H2 with noble-metal-free molecular devices comprising a porphyrin photosensitizer and a cobaloxime catalyst.

Among three noble-metal-free molecular devices (1-3) containing a porphyrin photosensitizer and a cobaloxime catalyst, the one with a zinc porphyrin unit displayed apparently higher efficiency for photoinduced H(2) production than complex 2 with a magnesium porphyrin and 3 with a free-base porphyrin, possibly due to the formation of a TEAZnPor-Co triad in solution.

Investigation of the wetting behavior of coal tar in three phase systems and its modification by poloxamine block copolymeric surfactants.

The removal of dense nonaqueous phase liquid mixtures (DNAPLs) from rocks and subsurface soils is an ongoing remedial challenge. Very often the wetting preferences of the system are not altered by exposure to the DNAPL. However, there are systems where the wetting properties of the solid phase have been altered from strongly water wetting by exposure to the DNAPL. In these cases some technique is necessary for reducing the work of adhesion between the DNAPL and the mineral surface. The focus of this report is the problems posed by coal tar in unconsolidated sands. It is shown that coal tar can alter the wetting properties of quartz, the principal component of sands, and is thus capable of adhering to the surface. In this investigation the ability of several members of the poloxamine family of polymeric surfactants to aid in the removal of coal tar from sand was evaluated. The poloxamines are tetrafunctional block copolymeric surfactants, which contain four poly(ethylene oxide)-block-poly(propylene oxide) chains joined to a central ethylenediamine moiety via the nitrogen atoms. Contact angle measurements of coal tar on a quartz surface immersed in aqueous surfactant solution and the interfacial tension between coal tar and aqueous surfactant solution have been measured. Coal tar/water interfacial tensions are reduced to values in the region of 2 mN m(-1) at surfactant concentrations of approximately 0.1 w/v %. Poloxamine surfactant impact on the static contact angle is more complex. In some cases the polymeric surfactants alter the wetting behavior from strongly water wetting to weakly water wetting. However, other poloxamines appear to have little if any impact on the contact angle, which remains strongly water wetting. The foregoing measurements have then been used to calculate the work of adhesion of the coal tar to quartz and the results qualitatively compared with the concentration of surfactant solution required to visually demonstrate the complete de-adhesion of coal tar to the quartz. It is shown that at surfactant concentrations below the critical micelle concentration (cmc) of the surfactant, the work of adhesion can be reduced sufficiently to ensure complete removal of coal tar from both quartz and sand.