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A mononuclear compound, [Co(L1)2(H2O)]·2H2O (1), where L1 = N,N-bis(3,5-dichlorosalicylidene)hydrazine, was synthesized under hydrothermal conditions. Note that L1 is derived from the hydrothermal in situ reaction of L2 (L2 = 3,5-dichlorosalicylaldehyde thiosemicarbazone). L2 is prepared by reflux using 3,5-dichlorosalicylic aldehyde and thiosemicarbazide. Although 1 is only a mononuclear structure coordinated with L1, intermolecular hydrogen-bonded interactions between two adjacent mononuclear units creates a 1D supramolecular chain. Furthermore, it self-assembles into a fascinating 2D supramolecular layer via π⋅⋅⋅π stacking between benzene rings of adjacent chains. Hirshfeld surfaces and fingerprint maps of 1 were applied to obtain data on non-covalent interactions. Antibacterial analysis shows that 1 is a potential antibacterial material and the bacteriostasis rate is higher than that of L1 (E. coli: 89.41% for 1, 29.09% for L1; MRSA: 93.17% for 1, 38.54% for L1). The solid and liquid photoluminescence properties of 1 and L1 were also investigated. [ABSTRACT FROM AUTHOR]

• A novel Pb(II) coordination polymer [Pb(FDPTH)(phen)] (1 ; FDPTH =4,4′ hexafluoroisoprorylidene-diphthalhydrazidate, phen = 1,10-phenanthroline) with 3D network structure was obtained. • The FDPTH ligands derived from the hydrothermal in situ acylation reactions. • Compound 1 is a potential visible light catalyst. • The mechanism of photocatalytic reaction was deeply studied. A new coordination polymer photocatalyst, [Pb(FDPTH)(phen)] (1 ; FDPTH 4,4′ hexafluoroisoprorylidene-diphthalhydrazidate, phen = 1,10-phenanthroline) was synthesized for the frist time. The FDPTH ligand was obtained by the in situ acylation reactions between 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDCA) and N 2 H 4 ·H 2 O for the first time. X-ray single-crystal diffraction analysis showed that FDPTH ligands have a μ 4 -bridging mode in compound 1 , which linking Pb(II) centers to create a 3D network structure. Hirshfeld surface analysis was used to investigate the crystal packing and interactions of compound 1. The catalytic activity of compound 1 for methylene blue (MB) was tested under visible light. The degradation for MB followed a pseudo-first-order kinetic pattern and remained efficient after repeated experimental runs. The active species in catalytic process were discovered by radical trapping experiments. The band gap of compound 1 was determined via UV-vis absorbance spectra and Mott-Schottky plot, and a photocatalytic mechanism was proposed for the degradation process. [Display omitted] A new coordination polymer photocatalyst, [Pb(FDPTH)(phen)] (1 ; FDPTH =4,4′ hexafluoroisoprorylidene-diphthalhydrazidate, phen = 1,10-phenanthroline) was synthesized for the frist time. The FDPTH ligand was obtained by the in situ acylation reactions between 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDCA) and N 2 H 4 ·H 2 O for the first time. X-ray single-crystal diffraction analysis showed that FDPTH ligands have a μ 4 -bridging mode in compound 1 , which linking Pb(II) centers to create a 3D network structure. Hirshfeld surface analysis was used to investigate the crystal packing and interactions of compound 1. The catalytic activity of compound 1 for methylene blue (MB) was tested under visible light. The degradation for MB followed a pseudo-first-order kinetic pattern and remained efficient after repeated experimental runs. The active species in catalytic process were discovered by radical trapping experiments. The band gap of compound 1 was determined via UV-vis absorbance spectra and Mott-Schottky plot, and a photocatalytic mechanism was proposed for the degradation process. [ABSTRACT FROM AUTHOR]

Graphdiyne (g−CnH2n‐2), a novel two‐dimension carbon allotrope material composed of a sp‐ and sp2‐hybrid carbon network, has been widely explored since it was synthesized for the first time by Li's group in 2010. A series distinct and excellent properties bestow graphdiyne excellent performance in many fields. Here, an innovative progress for preparing graphdiyne by using Cu+ contained material as catalyst is reported and the composite CuI‐GD is coupled with flower‐like NiAl‐LDH to produce H2 from photocatalytic water splitting. The results of FTIR and Raman spectroscopy together reveal that graphdiyne nanosheets are synthesized successfully by employing a cross‐coupling method. Photocatalytic hydrogen evolution performance shows that the hydrogen production activity of CuI‐GD/NiAl‐LDH has a 15‐ and 216‐fold enhancement compared with CuI‐GD and NiAl‐LDH, respectively. A series of characterizations are carried out to expound the underlying reasons in the enhancement of the photocatalytic hydrogen production performance of CuI‐GD/NiAl‐LDH. Meanwhile, a possible mechanism for the photocatalytic hydrogen evolution process was proposed to understand the interaction among these materials. [ABSTRACT FROM AUTHOR]

• Two new compounds Zn(L1) 1 and Ni(L1)(H 2 O) 2 with 2D supermolecule layer structure were synthesized using the slow evaporation method at room temperature. • Compounds 1 showed significant antibacterial activity for MRSA. • Molecular docking of protein and DNA for compounds 1-2 were investigated. • The potential antibacterial mechanism of compounds 1-2 was proposed via combining with theoretical calculation and experimental results. Two novel compounds namely Zn(L1)(H 2 O) 1 and Ni(L1) 2 (L1 = 3, 5-dichlorosalicylaldehyde o-phenylenediamine) were synthesized by the slow evaporation method of aqueous solution at room temperature. The structure of the ligand L1 was optimized using DFT, and it was demonstrated that the potential coordination sites between the calculated metal ions and the ligand structure were consistent with the experimental results. X-ray single-crystal diffraction analysis indicated that compounds 1-2 formed 2D supramolecular layer structures through π ··· π stacking or hydrogen bonding interactions. Hirshfeld surface analysis revealed that Cl...H interactions were the predominant interactions in compounds 1-2. Furthermore, the energy framework analysis indicated that dispersion energy played a dominant role in the energy composition of these compounds. The results of antibacterial experiments for Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA) indicated compound 1 was a potential antibacterial agent for MRSA (inhibition zone: 15 mm). The ion release capacity of compounds 1-2 was evaluated by ion release experiments, resulting in the release of Zn(II) ions (24.81 µg/mL after 4 days) and Ni(II) ions (14.40 µg/mL after 4 days). Molecular docking analysis revealed the interaction modes of compounds 1-2 with UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and dihydrofolate reductase (DHFR) in bacteria, which involved hydrophobic, stacking, hydrogen bonding, and halogen bonding interactions. Potential antibacterial mechanisms of compounds 1-2 were proposed. Two novel compounds namely Zn(L1) 1 and Ni(L1)(H 2 O) 2 (L1 = 3, 5-dichlorosalicylaldehyde o-phenylenediamine) were synthesized by the slow evaporation method of aqueous solution at room temperature. The structure of the ligand L1 was optimized using DFT, and it was demonstrated that the potential coordination sites between the calculated metal ions and the ligand structure were consistent with the experimental results. X-ray single-crystal diffraction analysis indicated that compounds 1-2 formed 2D supramolecular layer structures through π ··· π stacking or hydrogen bonding interactions. Hirshfeld surface analysis revealed that Cl...H interactions were the predominant interactions in compounds 1-2. Furthermore, the energy framework analysis indicated that dispersion energy played a dominant role in the energy composition of these compounds. The results of antibacterial experiments for Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA) indicated compound 1 was a potential antibacterial agent for MRSA (inhibition zone: 15 mm). The ion release capacity of compounds 1-2 was evaluated by ion release experiments, resulting in the release of Zn(II) ions (24.81 µg/mL after 4 days) and Ni(II) ions (14.40 µg/mL after 4 days). Molecular docking analysis revealed the interaction modes of compounds 1-2 with UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and dihydrofolate reductase (DHFR) in bacteria, which involved hydrophobic, stacking, hydrogen bonding, and halogen bonding interactions. Potential antibacterial mechanisms of compounds 1-2 were proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

Two new compounds namely [Zn(L1)phen] 3 1 and Ni(L1)phen(MeOH) 2 (L1 = 3, 5-dichlorosalicylaldehyde thiosemicarbazone) were synthesized by the slow evaporation method at room temperature. The structure of ligand L1 was determined using 1H NMR and 13C NMR spectra. X-ray single crystal diffraction analysis revealed that compounds 1 – 2 can form 3D supramolecular network structures through π ··· π stacking and hydrogen bonding interactions. The DFT calculation shows that the coordination of ligand and metal is in good agreement with the experimental results. Hirshfeld surface analysis revealed that H...H and Cl...H interactions were the predominant interactions in compounds 1 – 2. Energy framework analysis indicated that dispersion energy played a dominant role in the energy composition of compounds 1 – 2. The inhibitory effects of compounds 1 – 2 against Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA) were tested using the paper disk diffusion method (1 : E. coli: 18 mm, MRSA: 17 mm, 2 : E. coli: 15 mm, MRSA: 16 mm). Ion releasing experiments were conducted to assess the ion release capacity of compounds 1 – 2 (Zn2+, 4 days, 38.33 µg/mL; Ni2+, 4 days, 29.12 µg/mL). Molecular docking demonstrated the interaction modes of compounds 1 – 2 with UDP- N -acetylenolpyruvoylglucosamine reductase (MurB) and dihydrofolate reductase (DHFR) in bacteria, involving hydrophobic, stacking, hydrogen bonding and halogen bonding interactions. The generation of reactive oxygen species (ROS) in bacteria under the presence of compounds 1 – 2 were evaluated using a fluorescent dye known as dichlorodihydrofluorescein diacetate (DCFH-DA). Potential antibacterial mechanisms of compounds 1 – 2 were proposed. [Display omitted] • Two new compounds [Zn(L1)phen] 3 1 and Ni(L1)phen(MeOH) 2 were synthesized under room temperature. • Compounds 1 – 2 were both extended into a 3D supermolecule network structure via π ··· π stacking and hydrogen bonding interactions. • Compounds 1 – 2 were both potential antibacterial bacterial for E. coli and MRSA (1 : E. coli: 18 mm, MRSA: 17 mm, 2 : E. coli: 15 mm, MRSA: 16 mm). • Molecular docking of protein and DNA for compounds 1 – 2 were investigated. • The potential antibacterial mechanism of compounds 1 – 2 was proposed via combining with theoretical calculation and experimental results. Two new compounds namely [Zn(L1)phen] 3 1 and Ni(L1)phen(MeOH) 2 (L1 = 3, 5-dichlorosalicylaldehyde thiosemicarbazone) were synthesized by the slow evaporation method at room temperature. The structure of ligand L1 was determined using 1H NMR and 13C NMR spectra. X-ray single crystal diffraction analysis revealed that compounds 1 – 2 can form 3D supramolecular network structures through π ··· π stacking and hydrogen bonding interactions. The DFT calculation shows that the coordination of ligand and metal is in good agreement with the experimental results. Hirshfeld surface analysis revealed that H...H and Cl...H interactions were the predominant interactions in compounds 1 – 2. Energy framework analysis indicated that dispersion energy played a dominant role in the energy composition of compounds 1 – 2. The inhibitory effects of compounds 1 – 2 against Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA) were tested using the paper disk diffusion method (1 : E. coli: 18 mm, MRSA: 17 mm, 2 : E. coli: 15 mm, MRSA: 16 mm). Ion releasing experiments were conducted to assess the ion release capacity of compounds 1 – 2 (Zn2+, 4 days, 38.33 µg/mL; Ni2+, 4 days, 29.12 µg/mL). Molecular docking demonstrated the interaction modes of compounds 1 – 2 with UDP- N -acetylenolpyruvoylglucosamine reductase (MurB) and dihydrofolate reductase (DHFR) in bacteria, involving hydrophobic, stacking, hydrogen bonding and halogen bonding interactions. The generation of reactive oxygen species (ROS) in bacteria under the presence of compounds 1 – 2 were evaluated using a fluorescent dye known as dichlorodihydrofluorescein diacetate (DCFH-DA). Potential antibacterial mechanisms of compounds 1 – 2 were proposed. [ABSTRACT FROM AUTHOR]

• A novel coordination polymer photocatalyst [Zn(FDPTH)(bpy)] 1 (FDPTH = 4,4′-hexafluoroisoprorylidene-diphthalhydrazidate, bpy = 2,2′-bipyridine) with 2D supramolecular layer was obtained. • FDPTH ligands derived from the hydrothermal in situ acylation reactions. • Compound 1 is a potential visible light catalyst. • The mechanism of photocatalytic reaction is studied deeply. Under the hydrothermal conditions, a novel visible-light-driven coordination polymer photocatalyst [Zn(FDPTH)(bpy)] 1 (FDPTH = 4,4′-hexafluoroisoprorylidene-diphthalhydrazidate, bpy = 2,2′-bipyridine) was luckily obtained for the first time. Note that FDPTH derived from the hydrothermal in situ acylation reactions between 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDCA) and N 2 H 4 ⋅H 2 O. X-ray single-crystal diffraction analysis revealed that the FDPTH ligands exhibit a μ 3 -bridging mode in compound 1 , which link Zn(II) centers into a 1D chained structure with auxiliary ligand. The crystal packing of the synthesized compound was further analyzed using Hirshfeld surface analysis (HSA) to assess the interactions between the crystal packings. The photocatalysis analysis indicates that compound 1 is a potential visible-light-driven photocatalyst. The degradation follows a pseudo-first-order kinetic character and the efficiency has been well preserved after five continuous experimental runs. Trapping radical experiment turned out that the ·OH are active species in the catalytic reaction. The band position of compound 1 was elucidated via UV–vis absorbance spectra and Mott-Schottky plot. Also, the photocatalytic degradation mechanism has been proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

We studied the effects of copper (Cu) phytoremediation on microbial community composition under laboratory conditions. A Cu accumulator, Commelina communis, was grown on a soil containing different gradients of Cu. Results showed that the biomass of C. communis grown with Cu differed from that of the control. Concentrations of Cu in the shoots of C. communis were 73.6, 160.9, and 319.1 mg kg-1 under 200, 500, and 1000 mg kg-1 Cu treatments, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprint analysis revealed that additions of Cu decreased the number of bands in the soil with C. communis or without plants. The principal component analysis explained 52.7% of the variance for the different rhizospheres of soil and Cu treatments in the soil samples. These results indicated significant effects on soil bacteria activity and community composition in the rhizosphere of C. communis and provided a basis for further studies of metal-accumulator plant effects on soil microorganisms. [ABSTRACT FROM AUTHOR]

Abstract: All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C (Cmic)/organic C (Corg) ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient. [Copyright &y& Elsevier]

Abstract: To study Pseudomonas putida CZ1, having high tolerance to copper and zinc on the removal of toxic metals from aqueous solutions, the biosorption of Cu(II) and Zn(II) by living and nonliving P. putida CZ1 were studied as functions of reaction time, initial pH of the solution and metal concentration. It was found that the optimum pH for Zn(II) removal by living and nonliving cells was 5.0, while it was 5.0 and 4.5, respectively, for Cu(II) removal. At the optimal conditions, metal ion biosorption was increased as the initial metal concentration increased. The adsorption data with respect to both metals provide an excellent fit to the Langmuir isotherm. The binding capacity of living cells is significantly higher than that of nonliving cells at tested conditions. It demonstrated that about 40–50% of the metals were actively taken up by P. putida CZ1, with the remainder being passively bound to the bacterium. Moreover, desorption efficiency of Cu(II) and Zn(II) by living cells was 72.5 and 45.6% under 0.1M HCl and it was 95.3 and 83.8% by nonliving cells, respectively. It may be due to Cu(II) and Zn(II) uptake by the living cells enhanced by intracellular accumulation. [Copyright &y& Elsevier]

Abstract: The role of rhizosphere bacteria in facilitating the solubility of copper (Cu) in contaminated soil and Cu accumulation in plant were studied. The bacteria strains were isolated from the rhizosphere of Elsholtzia splendens, a Cu accumulator growing on Tonglu Mountain copper mines. After the sandy soils containing 237 mg kg−1 were incubated with the bacteria strains, it was indicated that rhizosphere microbes played an important role in influencing the availability of water-soluble Cu in soils. Soils had greater concentrations of water-extractable Cu compared with axenic soils inoculated with different bacterial strains. Further evidence for bacterial facilitation of increased solubility of Cu in the soil was obtained using the antibiotic ampicillin (0.1 mg g− 1). There were 36% decreases in Cu concentration in the presence of bacterial strain MS12 and ampicillin together compared with bacterial inoculation alone. Different bacterial strains had different abilities on soil water-soluble Cu. To achieve the highest rates of plant Cu accumulation, it was necessary for bacteria to be present in the rhizosphere of E. splendens. Inoculated plants supplied with 20 μmol L− 1 CuSO4 had significantly greater concentrations of Cu in shoots and roots than uninoculated plants and bacterial strain MS2 was the most effective strain in promoting plant Cu uptake. There were 2.2-fold and 2.5-fold increases in Cu accumulation in the shoots and roots of plants inoculated with strain MS2 compared to axenic controls. Furthermore, when ampicillin and the bacterial strains were added together to the nutrient solution, the Cu concentrations in roots and shoots of ampicillin-treated plants were lower than those in inoculated plants. When ampicillin was added to the nutrient solution, Cu accumulation was inhibited by about 24–44% in shoots and 20–44% in roots. The above results provided a new insight into the phytoremediation of Cu-contaminated soil. [Copyright &y& Elsevier]

An experiment was conducted to investigate flow-induced vibration (FIV) in the control rods of a pressurized-water reactor (PWR). Control rods and a guide cylinder (full scale compared with the real structure) were installed on an FIV experiment platform, with which flow distributions were simulated according to actual situations. The vibration displacements of the control rods were observed in different flow rate ranges of transverse and vertical flows. Several FIV characteristics of the control rods under different transverse and vertical flows were determined by analyzing the experimental results. A formula was also proposed to predict vibration. [ABSTRACT FROM AUTHOR]

[Display omitted] • The identification of anions in water by LMOFs containing aromatic acids was summarized. • Types of LMOFs were divided into three categories: "turn-on", "turn-off" and "ratiometric". • The mechanism of anion recognition by LMOFs was studied deeply. At present, industrial wastewater and domestic sewage have caused serious water pollution, which not only affects the quality of human life, but also pollutes the ecological environment. Anions exist in water for a long time, causing serious water pollution, especially they are toxic. A new class of organic–inorganic hybrid material called metal–organic framework (MOF) has various benefits including a porous structure, adjustable pore size, and multi-metal sites. It is widely used in adsorption, storage, separation, catalyst and other fields. Aromatic carboxylic acids have many advantages over other N-containing ligand or S- or P- ligands or flexible carboxylic acid ligands. The aromatic ring structure of aromatic carboxylic acid molecules can accumulate π-π with other aromatic rings, which is conducive to enhancing the robustness of the coordination polymer. Aromatic carboxylic acid has a relatively rigid molecular structure, and has more degrees of freedom with other N-containing or S- or P- ligands or flexible carboxylic acid ligands, which is more conducive to the formation of specific spatial structures. Moreover, there are abundant π electrons in the aromatic ring, which provide abundant electrons in the coordination process. Most importantly, different substituents and functional groups can be introduced into the aromatic ring, and coordination polymers with specific properties can be designed and synthesized. By designing ligands and metal ions, MOFs can effectively regulate their luminescence properties, which has incomparable advantages over traditional luminescent materials. This review mainly introduces the detection of anions in water by using the unique fluorescence characteristics of MOFs. According to the changes of fluorescence sensing, detection and identification are divided into fluorescence enhancement "turn-on", fluorescence quenching "turn-off" and ratiometric fluorescence "ratiometric", and the detection mechanism of anions is briefly expounded. [ABSTRACT FROM AUTHOR]

Abstract: Silver was reclaimed from silver-plating wastewater by using a pulsed electric field (PEF) combined with static cylinder electrodes (SCE). The conditions that produced the maximal silver recovery rate (RR Ag) (99%) were as follows: average retention time of 10min, interelectrode gap of 50mm, solution pH of 9.0, temperature of 45°C, initial Ag(I) concentration of 1000mgL−1, PEF pulse frequency of 1200Hz, current density of 5.0Am−2 and a pulse duty cycle of 60%. Compared with the conventional direct current (DC) technology, the PEF process exhibited improvements in the silver recovery rate (RR Ag), total energy consumption (TEC) and physical properties of the silver deposits, especially for low Ag(I) concentrations, for example, from 500 to 1000mgL−1. For an initial Ag(I) concentration of 500mgL−1, the PEF process produced an RR Ag of up to 99%, and the TEC was 4.56kWh(kgAg)−1. In comparison, the RR Ag and TEC were 90% and 5.66kWh(kgAg)−1, respectively, in the DC process. The results of SEM observation and XRD analysis indicated that the silver deposits formed by the PEF process were smaller, denser, and of a higher purity than those produced by the DC process. Therefore, the presented method was effective for reclaiming silver from silver-plating wastewater. [Copyright &y& Elsevier]

A new Ni(II) compound [Ni(bim) 2 (H 2 O) 4 ] (1,5-nds)·(H 2 O) 0.5 1 (bim = benzimidazole, 1,5-nds-Na = disodium 1,5-naphthalenedisulfonate) was readily synthesized at room temperature. Although compound 1 is only a mononuclear compound, it is extended into a 2D supermolecule layer by hydrogen bonding interactions. Hirshfeld surfaces and fingerprint maps of compound 1 crystal packing were calculated to gather information on non-covalent interactions. Photoluminescence experiments showed that 1 not only possessed good solid-state fluorescence performance but also favorable fluorescence characteristics and stability in aqueous solutions, which can be exposed to acidic and alkaline environmental conditions (pH = 1–14) for a long time. Remarkably, compound 1 displayed outstanding anti-interference properties, high sensitivity, high quenching rate, and low limit of detection (LOD) against acetylacetone (acac), MnO 4 −, and tetracycline (TET) in water media via the Turn-Off effect (LOD:7.03 μM for acac, 2.92 μM for MnO 4 − and 0.65 μM for TET). Especially, compound 1 can also be used as a rare ratiometric fluorescent probe for the detection of Ag + down to the nM level. The exceptional multi-responsive performance suggested that compound 1 could be a potential multifunctional sensor. Furthermore, possible mechanisms were systematically investigated. [Display omitted] • A new compound [Ni(bim) 2 (H 2 O) 4 ](1,5-nds)·(H 2 O) 0.5 1 with a 2D supermolecule layered structure was directly synthesized. • Compound 1 is a multifunctional fluorescent sensor. • Compound 1 can detect acetylacetone, MnO 4 − and tetracycline by the turn off effect. • Compound 1 has a low detection limit for Ag + down to the nM level. • Compound 1 possess excellent fluorescence properties and stability in acid-base solutions. [ABSTRACT FROM AUTHOR]

A new strategy of redox mediator immobilization was developed by coating polydopamine (PDA) on individual live cells to enhance extracellular electron transfer. As a result of the synergistic effect of the redox properties of PDA and the ability to adsorb self-secreted flavin molecules, a double-mediator electron transport channel was achieved. [ABSTRACT FROM AUTHOR]

A nanocomposite of polystyrene-coated magnetic nanoparticles was successfully synthesized and employed as adsorbent for magnetic solid-phase extraction of four Sudan dyes (I, II III, and IV) in red wines, juices, and mature vinegars. The prepared magnetic nanoparticles with highly hydrophobic properties have excellent adsorption capacity for these lipophilic Sudan dyes. Extraction conditions were optimized. Experimental results showed that the recoveries of the four Sudan dyes were very satisfactory when 70 mg of polystyrene-coated magnetic nanoparticles were used and the extraction could be completed within 20 min. It was proved that these magnetic nanoparticles can be reused after an easy washing process. By coupling the magnetic solid-phase extraction with ultrafast liquid chromatography-ultraviolet spectrometry, a rapid, green, effective, and sensitive method for the determination of Sudan dyes was developed. The LOD for Sudan I, Sudan II, Sudan III, and Sudan IV were 0.0039, 0.0063, 0.0057, and 0.017 ng/mL, respectively. Recoveries obtained by analyzing spiked water samples at three concentration levels (0.1, 1.0, and 10.0 ng/mL) were between 76.3 and 96.6%. The intra- and interday RSDs for the analytes were lower than 9.6%. [ABSTRACT FROM AUTHOR]