13 research outputs found

    Temperature Effect on Photoelectrochemical Water Splitting: A Model Study Based on BiVO<sub>4</sub> Photoanodes

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    Photoelectrochemical (PEC) water splitting is typically studied at room temperature. In this work, the temperature effect on PEC water splitting is studied using crystalline BiVO4 thin film photoanode as a model system. Systematic temperature-dependent electrochemical study demonstrates that the PEC activity is boosted at elevated electrolyte temperatures and indicates that thermal energy plays a main role in improving charge carrier transport in the bulk of BiVO4. Irreversible surface reconstruction is observed after PEC reactions at elevated temperature in the presence of hole scavengers, with regularly spaced stripes emerging on BiVO4 grains. The surface-reconstructed photoanode exhibits up to 40% improvement in photocurrent densities and ∼ 0.25 V shift of photocurrent onset to favorable direction. Detailed investigation shows the formation of an amorphous layer without stoichiometric change at the reconstructed surface. This work provides insights of the temperature effect on the photoelectrode in solar water splitting and reveals the non-negligible effect of hole scavengers in photoelectrochemical measurement

    Porphyrin-Containing Metallacage with Precise Active Sites and Super Long-Term Stability as a Specific Peroxidase Mimic for Versatile Analyte Determination

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    Inspired by the architecture of single-atom catalysts, where the monodispersed metal atoms are widely distributed but stabilized by various coordination circumstances, the biomimetic design and synthesis of metalloporphyrin-containing nanocages have been demonstrated in this study. The nanocages were fabricated through a coordination-driven self-assembly process, and the Mn(III) porphyrin-based one was found to have exclusively peroxidase-like activity at pH 6.0 with neither oxidase nor catalase-like activity under the routine conditions. Benefiting from this, we demonstrated the wide applicability and convenient usage of an Mn(III)-containing supramolecular nanocage (Mn-PC) in the one-step detection of H2O2, sarcosine, and glucose through various oxidase-involved reactions, with a satisfactory detection limit and eligible specificity. Real samples including H2O2 in lens care solution, sarcosine in human urine, and glucose in human serum were also assayed, showing an adequate recovery rate. Such a specific activity originates from the super-consistent microstructure of each catalytic unit, which means that the active site of manganese porphyrin was “protected” by the confinement of the nanocage. This also helps to sustain the super long-term activity even after 545 days of storage. Furthermore, the intrinsic electronic structure of the Mn(III)-containing supramolecular nanocage endows the ability in electrochemical detection of H2O2 and glucose. Our smart design toward the supramolecular nanocages with a defined structure and quantity contributes to the construction of the ingenious sensing platform and has guiding significance for architectural design of nanozymes

    DataSheet1_Efficacy of Forsythia suspensa (Thunb.) Vahl on mouse and rat models of inflammation-related diseases: a meta-analysis.zip

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    Objective: To evaluate the efficacy of the fruits of the medicinal plant Forsythia suspensa (Thunb.) Vahl (FS), in treating inflammation-associated diseases through a meta-analysis of animal models, and also probe deeply into the signaling pathways underlying the progression of inflammation.Materials and methods: All data analyses were performed using Review Manager 5.3 and the results are presented as flow diagrams, risk-of-bias summaries, forest plots, and funnel plots. Summary estimates were calculated using a random- or fixed-effect model, depending on the value of I2.Results: Of the 710 records identified in the initial search, 11 were selected for the final meta-analysis. Each study extracted data from the model and treatment groups for analysis, and the results showed that FS alleviated the inflammatory cytokine levels in serum; oxidant indicator: reactive oxygen species; enzymes of liver function; endotoxin and regulatory cells in blood; and improved the antioxidant enzyme superoxide dismutase.Conclusion: FS effectively reversed the change in acute or chronic inflammation indicators in animal models, and the regulation of multiple channel proteins in inflammatory signaling pathways suggests that FS is a good potential drug for inflammatory disease drug therapy.</p

    Cobalt Oxide-Coated Single Crystalline Bismuth Vanadate Photoanodes for Efficient Photoelectrochemical Chlorine Generation

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    Bismuth vanadate (BiVO4) is an outstanding photoanode material for photoelectrochemical water splitting. In this work, a series of single crystalline BiVO4 photoanodes are synthesized by pulsed laser deposition (PLD). Once coated with a thin layer of cobalt oxide (CoOx) cocatalyst, also by PLD, the photoanodes support efficient photoelectrochemical generation of chlorine (Cl2) from brine under simulated solar light. The activity of the chlorine generation reaction (ClER) is optimized when the thickness of CoOx is about 3 nm, with the faradic efficiency of ClER exceeding 60%. Detailed studies show that the CoOx cocatalyst layer is amorphous, uniform in thickness, and chemically robust. As such, the cocatalyst also effectively protects the underlying BiVO4 photoanodes against chlorine corrosion. This work provides insights into using artificial photosynthesis for byproducts that carry significant economic value while avoiding the energetically expensive oxygen evolution reactions

    Table_1_The effect of oregano essential oil on the prevention and treatment of Salmonella pullorum and Salmonella gallinarum infections in commercial Yellow-chicken breeders.DOCX

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    In order to prevent pullorum disease and fowl typhoid in breeders, the use of oregano essential oil (OEO) was tested for the prevention and treatment of infections of multidrug-resistant Salmonella pullorum (SP) and Salmonella gallinarum (SG) in commercial Yellow-chicken breeders. In the challenge-protection experiment, commercial Hongguang-Black 1-day-old breeder chicks were randomly divided into four groups, including A (challenged, preventive dose), B (challenged, treatment dose), C (challenged, untreated), and D (unchallenged, untreated). Group A was supplemented with 200 μL/L OEO in the drinking water during the whole trial (1-35 days of age) and group B was supplemented with 400 μL/L OEO during 8–12 days of age, while groups C and D were kept as untreated controls. At 7 days of age, birds of groups A, B, and C were divided into two subgroups with equal number of birds (A1-A2, B1-B2, and C1-C2), and then subgroups A1, B1, and C1 were challenged with SP, while subgroups A2, B2, and C2 were challenged with SG. Clinical symptoms and death were observed and recorded daily. Every week during the experiment, serum antibodies against SP and SG of all the groups were detected by the plate agglutinate test (PAT). At the age of 35 days, all birds were weighed and necropsied, lesions were recorded and the challenging pathogens were isolated. The results showed that the positive rates of SP and SG isolation in groups A1, A2 and B1, B2 were significantly lower (P 1 and C2, respectively, while groups A1 and A2 were slightly lower (P > 0.05) than those of groups B1 and B2. The average body weight (BW) of groups A1 and A2 were significantly higher (P 1, B2 and C1, C2, respectively, but there was no significant difference (P > 0.05) with that of group D. The r-value between PAT positive and the recovery rates of Salmonella was 0.99, which means they are highly positively correlated. The results of this study demonstrated that the prevention dose (200μL/L) and the treatment dose (400 μL/L) of OEO supplemented in the drinking water could all effectively decrease infections of SP and SG and that the effect of the prevention was greater than that of the treatment and finally that the prevention could also significantly reduce the BW decline of birds challenged with SP and SG.</p

    Chitosan–Fe(III) Complexes via Green Preparation toward Flame Retardant and High-Mechanical-Strength Epoxy Composites

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    Biobased flame retardants with facile preparation, high performance in smoke suppression, and mechanical reinforcement toward epoxy resins are worth exploring for feasible sustainability. Although some chitosan-containing flame retardants have been successfully developed so far, the synthesis processes for most of them require the use of large volumes of organic solvents and give low synthetic yields. Herein, we report a facile, green, and high-yielding strategy for the synthesis of chitosan–metal complex flame retardants (CS–Fe) by coordination of chitosan with Fe­(III) in water. The results show that incorporating 9 wt % CS–Fe enables the EP composites to pass the UL-94 V-1 rating with a limiting oxygen index (LOI) of 29.5%. At the same time, the peak heat release rate, peak smoke production, total smoke production, peak CO production, and fire growth rate of EP/9CS–Fe are significantly reduced, indicating good flame retardancy. Remarkably, the prepared CS–Fe enhanced both the strength and toughness of EP due to the homogeneous dispersion of CS–Fe and the presence of a reaction between CS–Fe and the EP matrix. This work provides a simple and economic strategy for the green preparation of chitosan-based flame retardants with high efficiency

    Data_Sheet_1_The effect of oregano essential oil on the prevention and treatment of Salmonella pullorum and Salmonella gallinarum infections in commercial Yellow-chicken breeders.DOC

    No full text
    In order to prevent pullorum disease and fowl typhoid in breeders, the use of oregano essential oil (OEO) was tested for the prevention and treatment of infections of multidrug-resistant Salmonella pullorum (SP) and Salmonella gallinarum (SG) in commercial Yellow-chicken breeders. In the challenge-protection experiment, commercial Hongguang-Black 1-day-old breeder chicks were randomly divided into four groups, including A (challenged, preventive dose), B (challenged, treatment dose), C (challenged, untreated), and D (unchallenged, untreated). Group A was supplemented with 200 μL/L OEO in the drinking water during the whole trial (1-35 days of age) and group B was supplemented with 400 μL/L OEO during 8–12 days of age, while groups C and D were kept as untreated controls. At 7 days of age, birds of groups A, B, and C were divided into two subgroups with equal number of birds (A1-A2, B1-B2, and C1-C2), and then subgroups A1, B1, and C1 were challenged with SP, while subgroups A2, B2, and C2 were challenged with SG. Clinical symptoms and death were observed and recorded daily. Every week during the experiment, serum antibodies against SP and SG of all the groups were detected by the plate agglutinate test (PAT). At the age of 35 days, all birds were weighed and necropsied, lesions were recorded and the challenging pathogens were isolated. The results showed that the positive rates of SP and SG isolation in groups A1, A2 and B1, B2 were significantly lower (P 1 and C2, respectively, while groups A1 and A2 were slightly lower (P > 0.05) than those of groups B1 and B2. The average body weight (BW) of groups A1 and A2 were significantly higher (P 1, B2 and C1, C2, respectively, but there was no significant difference (P > 0.05) with that of group D. The r-value between PAT positive and the recovery rates of Salmonella was 0.99, which means they are highly positively correlated. The results of this study demonstrated that the prevention dose (200μL/L) and the treatment dose (400 μL/L) of OEO supplemented in the drinking water could all effectively decrease infections of SP and SG and that the effect of the prevention was greater than that of the treatment and finally that the prevention could also significantly reduce the BW decline of birds challenged with SP and SG.</p

    Reverse logistics pricing strategy for a green supply chain: a view of customers’ environmental awareness

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    The effectiveness of a reverse logistics strategy is contingent upon the successful execution of activities related to materials and product reuse. Green supply chain (GSC) in reverse logistics aims to minimize byproducts from ending up in landfills. This paper considers a retailer responsible for recycling and a manufacturer responsible for remanufacturing. Customer environmental awareness (CEA) is operationalized as customer word-of-mouth effect. We form three game theoretic models for two different scenarios with different pricing strategies, i.e. a non-cooperative pricing scenario based on Stackelberg equilibrium and Nash equilibrium, and a joint pricing scenario within a cooperative game model. The paper suggests that stakeholders are better off making their pricing and manufacturing decision in cooperation

    Probing Oxidation-Driven Amorphized Surfaces in a Ta(110) Film for Superconducting Qubit

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    Recent advances in superconducting qubit technology have led to significant progress in quantum computing, but the challenge of achieving a long coherence time remains. Despite the excellent lifetime performance that tantalum (Ta) based qubits have demonstrated to date, the majority of superconducting qubit systems, including Ta-based qubits, are generally believed to have uncontrolled surface oxidation as the primary source of the two-level system loss in two-dimensional transmon qubits. Therefore, atomic-scale insight into the surface oxidation process is needed to make progress toward a practical quantum processor. In this study, the surface oxidation mechanism of native Ta films and its potential impact on the lifetime of superconducting qubits were investigated using advanced scanning transmission electron microscopy (STEM) techniques combined with density functional theory calculations. The results suggest an atomistic model of the oxidized Ta(110) surface, showing that oxygen atoms tend to penetrate the Ta surface and accumulate between the two outermost Ta atomic planes; oxygen accumulation at the level exceeding a 1:1 O/Ta ratio drives disordering and, eventually, the formation of an amorphous Ta2O5 phase. In addition, we discuss how the formation of a noninsulating ordered TaO1−δ (δ < 0.1) suboxide layer could further contribute to the losses of superconducting qubits. Subsurface oxidation leads to charge redistribution and electric polarization, potentially causing quasiparticle loss and decreased current-carrying capacity, thus affecting superconducting qubit coherence. The findings enhance the comprehension of the realistic factors that might influence the performance of superconducting qubits, thus providing valuable guidance for the development of future quantum computing hardware

    The Role of Surface Oxygen Vacancies in BiVO<sub>4</sub>

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    Bismuth vanadate (BiVO4) is a widely studied oxide in solar water splitting, known for its ease of synthesis, high charge extraction yields, and advantageous band alignment with water. We present a combined first-principles and experimental study of the electronic structure of the (010) surface of BiVO4 aimed at disentangling the impact of the surface and bulk oxygen vacancies on the electronic structure and transport properties. We found that oxygen vacancies are deep donors at the surface as they are in the bulk; our calculations on defect and polaron formation energies suggest that, while polarons formed from oxygen vacancies in the bulk can contribute to conductivity, those at the surface likely do not. Our results also show that out-of-plane structural relaxations at the surface contribute to the relatively immobile nature of electron polarons derived from surface oxygen vacancies. The structural model derived from first-principles calculation was validated by comparing computed results with experimental measurements of single-crystal and epitaxially grown single-crystalline BiVO4 samples. We also found a reasonably good agreement between our calculated and measured work functions for BiVO4 samples with and without oxygen vacancies
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