Understanding the origin of formation and active sites of oxygen evolution reaction (OER) cocatalysts is highly required for solar photoelectrochemical (PEC) devices that generate hydrogen efficiently from water. Herein, we employed a simple pH‐modulated method for in situ growth of FeNi oxyhydroxide ultrathin layers on BiVO4 photoanodes, resulting in one of the highest currently known PEC activities of 5.8 mA cm−2 (1.23 VRHE, AM 1.5 G) accompanied with an excellent stability. More importantly, both comparative experiments and density functional theory (DFT) studies clearly reveal that the selective formation of Bi−O−Fe interfacial bonds mainly contributes the enhanced OER activities, while the construction of V−O−Ni interfacial bonds effectively restrains the dissolution of V5+ ions and promotes the OER stability. Thereby, the synergy between iron and nickel of FeNi oxyhydroxides significantly improved the PEC water oxidation properties of BiVO4 photoanodes.

Summary The Bacillus subtilis MntR metalloregulatory protein senses manganese, an essential element required for central metabolism, oxidative stress resistance and replication. An mntR null mutant is highly sensitive to Mn(II) intoxication, which is attributed in part to the constitutive expression of two importers: the proton-dependent NRAMP family transporter MntH and the ABC transporter MntABCD. Here, we show that an mntR null mutant is still sensitive to Mn(II) intoxication even if both of the import systems are absent. This Mn(II) sensitivity results from the requirement for MntR to activate the transcription of two genes encoding cation diffusion facilitator (CDF) family efflux pumps. Physiological studies indicate that MneP (formerly YdfM) serves as the primary Mn(II) efflux pump with MneS (formerly YeaB) playing a secondary role. Mutant strains lacking mneP are Mn(II) sensitive and accumulate elevated levels of Mn(II), and these effects are exacerbated in a mneP mneS double mutant. DNA-binding and in vitro transcription studies demonstrate that MntR binds to both the mneP and mneS regulatory regions and directly activates transcription in response to levels of Mn(II) several-fold higher than required for repression of import genes. These results highlight the delicate balance of Mn(II) uptake and efflux systems controlled by MntR.

Semen Ziziphus jujube (SZJ), the seeds of Ziziphus jujuba Mill. var. spinosa, is a kind of traditional Chinese medicine used for its action on insomnia. In order to analyze the effective component, we investigated and compared the sedative and hypnotic effects of three kinds of compounds, flavonoids, saponins, and polysaccharides. Flavonoids, saponins, and polysaccharides were extracted from SZJ and orally administered to mice separately at 17 g kg(-1) per day for certain days before animal tests. Spontaneous motility and coordinated movement tests were used to observe the effects of the three kinds of compounds on the mouse behavior, and sodium barbital-induced sleeping time of mouse were tested to analyze the effects of the three kinds of compounds on the sleep of mouse. Results show that flavonoids and saponins caused a significant reduction of walking time and coordinated movement ability of mouse, significantly prolonged its sleeping time at 40 mg kg(-1), ip, subthreshold dose and increased the sleeping number of animals at 50 mg kg(-1), ip, superthreshold dose induced by coeliac injection of sodium barbital. Polysaccharides did not show any significance in all animal tests. Comparative analysis showed that saponins had a more effective sedative and hypnotic function than that of flavonoids, polysaccharides did not show a sedative and hypnotic effect.

Developing low-cost and highly efficient catalysts toward the efficient oxygen evolution reaction (OER) is highly desirable for photoelectrochemical (PEC) water splitting. Herein, we demonstrated that N-incorporation could efficiently activate NiFeOx catalysts for significantly enhancing the oxygen evolution activity and stability of BiVO4 photoanodes, and the photocurrent density has been achieved up to 6.4 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1.5 G). Systematic studies indicate that the partial substitution of O sites in NiFeOx catalysts by low electronegative N atoms enriched the electron densities in both Fe and Ni sites. The electron-enriched Ni sites conversely donated electrons to V sites of BiVO4 for restraining V5+ dissolution and improving the PEC stability, while the enhanced hole-attracting ability of Fe sites significantly promotes the oxygen-evolution activity. This work provides a promising strategy for optimizing OER catalysts to construct highly efficient and stable PEC water splitting devices.

The design of artificial receptors for sulfate ions is of great interest because of the importance of sulfate ions in environmental and biological systems.[1] One of the applications of sulfate ion receptors is extraction of the sulfate ion from nitrate-rich mixtures in the remediation of nuclear waste. [2] Based on liquid-liquid anion exchange technology, extraction of sulfate ions from an aqueous to an organic phase was realized by using macrocyclic receptors.[ ) of the receptor were needed in this case to ensure applicable extraction. Hence, the extraction efficiency has yet to be improved for sulfate ion extractants. This aim is quite challenging because of the extremely large hydration energy of the sulfate ion (DG h = À1080 kJ mol À1 for SO 4 2À compared to À300 kJ mol À1 for NO 3 À ) [3] according to the Hofmeister series, [4] as well as the high nitrate/sulfate ratios present in the crude waste. To overcome the Hofmeister bias, which disfavors the separation of the extremely hydrophilic sulfate ion from water, the receptor must have both excellent affinity and selectivity for sulfate ions.In recent years, some receptors for sulfate ions have been synthesized by employing different binding groups (mostly NH moieties), such as protonated Schiff base macrocycles, [5] diindolylureas, [6] and an M 4 L 6 cage containing a bipyridinefunctionalized monourea; [7] these receptors bind the anion in the 1:1, 3:1 and 6:1 (host/guest) mode, respectively. The trenbased tripodal trisurea backbone (L 1 ; tren = tris(2-aminoethyl)amine) has also been found to encapsulate the sulfate ion in a 2:1 (host/guest) ratio. [8] Although saturated coordination (12 hydrogen bonds) for sulfate and phosphate ions has been achieved by these receptors, the complementarity for the ions is not optimal in most cases. Calculations have demonstrated that the optimal saturated coordination mode for sulfate ions is binding in a tetrahedral cavity with 12 hydrogen bonds along the edges. [9] In this regard, the ideal sulfate ion receptor would possess a complementary tetrahedral cavity surrounded by 12 optimally arranged binding sites.The chelate effect may also play an important role in the host-guest binding affinity because of the favorable contributions from both entropy and enthalpy. As a typical example of the chelate effect, the Co 2+ complex of the bidentate ligand 1,2-diaminoethane is 10 8 times more stable than that of the unidentate ligand ammonia.[10] Moreover, the hexadentate ligand ethylenediaminetetraacetic acid (EDTA) displays extremely high binding affinities toward most metal ions (for example, 10 14.3 m À1 for Fe 2+ and 10 16.3 m À1 for Co 2+ ).[11]Given the similarities between anion coordination and classical transition-metal coordination chemistry, [12] increasing the number of binding sites to achieve high chelate effects should be an effective way to improve the extraction efficiency of sulfate ion extractants.We have devoted our efforts to the synthesis of selective anion receptors based on the urea functionality. [8a...