Ionic Liquid‐Hemoglobin‐Carbon Paste Composite Bioelectrode and Its Electrocatalytic Activity

A new carbon ionic liquid paste bioelectrode was fabricated by mixing hemoglobin (Hb) with graphite powder, ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIMBF₄) and liquid paraffin homogeneously. Nafion film was cast on the electrode surface to improve the stability of bioelectrode. Direct electrochemistry of Hb in the bioelectrode was carefully investigated. Cyclic voltammetric results indicated that a pair of well‐defined and quasi‐reversible electrochemical responses appeared in pH 7.0 phosphate buffer solution (PBS), indicating that direct electron transfer of Hb was realized in the modified electrode. The formal potential (E^0′) was calculated as ?0.316 V (vs. SCE), which was the typical characteristic of the electrochemical reaction of heme Fe(III)/Fe(II) redox couple. Based on the cyclic voltammetric results the electrochemical parameters of the electrode reaction were calculated. This bioelectrode showed high electrocatalytic activity towards the reduction of trichloroacetic acid (TCA) with good stability and reproducibility.     

Simultaneous Analysis of Hexaconazole, Myclobutanil, and Tebuconazole Residues in Apples and Soil by SPE Clean-Up and GC with Nitrogen–Phosphorus Detection

A facile and sensitive method utilizing capillary gas chromatography with nitrogen phosphorus detection (GC–NPD) has been developed and validated for simultaneous analysis of hexaconazole, myclobutanil, and tebuconazole, three broad-spectrum systemic fungicides, in apples and soil. Two samples were fortified with the three pesticides and subjected to ultrasonic extraction, followed by solid-phase extraction (SPE) to remove coextractives, before analysis by GC–NPD. SPE procedures were performed on PSA cartridges (500 mg, 3 mL), the analytes being eluted with n-hexane–acetone (9:1 v/v, 2 mL). Recovery of three pesticides from the fortified apple and soil samples ranged from 94.5 to 107.3% with relative standard deviations less than 9.7% at the three spike levels (0.01, 0.1, and 0.5 mg kg^?1). Limits of quantification of the method for apple and soil were 0.01 mg kg^?1, sufficiently below the maximum residue limits. Direct confirmation of the analytes in samples was achieved by gas chromatography–mass spectrometry (GC–MS).     

Enantioselective Resolution of γ-Lactam by a Whole Cell of <Emphasis Type="Italic">Microbacterium hydrocarbonoxydans</Emphasis> (L29-9) Immobilized in Polymer of PVA–Alginate–Boric Acid

Using immobilized cells of a novel strain of Microbacterium hydrocarbonoxydans L29-9 in polymers of polyvinyl alcohol (PVA)–alginate–boric acid, enantioselective resolution of racemic γ-lactam to produce (−)γ-lactam was successfully carried out. A 6:1 ratio of PVA:sodium alginate not only prevented agglomeration of the matrix but also produced beads with high gel strength. The optimum biotransformation conditions were 1 g/L substrate, pH 7.0, reaction temperature of 30 °C, and reaction time of 3 h. After every two cycles, the immobilized cell beads were separated and immersed in 0.5 mM KCl solution at 4 °C for preservation. At optimum conditions, the enantiomeric excess and the yield of (−)γ-lactam were >99% and 34%, respectively. The beads showed a slight decrease in the enantiomeric excess when re-used up to 14 cycles (the enantioselectivity of the immobilized cells decreased slightly after 14 cycles of usage).     

Cloning and Identification of a Novel P-II Class Snake Venom Metalloproteinase from <Emphasis Type="Italic">Gloydius halys</Emphasis>

Ahpfibrase was a new snake venom metalloproteinase (SVMP) which was cloned from Gloydius halys. The cDNA sequence with 1,891 base pairs encodes an open reading frame of 477 amino acids which includes a 17 amino acid signal peptide, plus a 171 amino acid segment of zymogen-like propeptide, a metalloproteinase domain of 200 amino acids, a spacer of 16 amino acids, and a disintegrin-like peptide of 73 amino acids. The metalloproteinase domain contained a conserved signature zinc-binding motif HEXXHXXGXXH in the catalytic region and a methionine-turn CIM. To determine the activity of ahpfibrase, the coding region including both the metalloproteinase domain and disintegrin region was amplified by PCR, inserted into the pET25b(+) vector, and expressed in Escherichia coli. The recombinant protein was recovered from inclusion bodies with 8 M urea and refolding was performed by fed-batch dilution method, and purified recombinant ahpfibrase showed the fibrinolytic activity and platelet aggregation–inhibition ability.     

Macroporous Co3O4 platelets with excellent rate capability as anodes for lithium ion batteries

This paper reports the microwave-assisted synthesis of Co₃O₄ nanomaterials with different morphologies including nanoparticles, rod-like nanoclusters and macroporous platelets. The new macroporous platelet-like Co₃O₄ morphology was found to be the best suitable for reversible lithium storage properties. It displayed superior cycling performances than nanoparticles and rod-like nanoclusters. More interestingly, excellent high rate capabilities (811 mAh g^?1 at 1780 mA g^?1 and 746 mAh g^?1 at 4450 mA g^?1) were observed for macroporous Co₃O₄ platelet. The good electrochemical performance could be attributed to the unique macroporous platelet structure of Co₃O₄ materials.     

Synthesis, electrochemical, and gas sensitivity performance of polyaniline/MoO3 hybrid materials

Hybrid material of polyaniline with molybdenum trioxide (MoO ₃ ) xerogel obtained by ion exchange of (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O was synthesized via polymerization of the monomer by ammonium peroxydisulfate/HCl oxidant system. The properties of MoO ₃ and hybrid material were investigated through thermogravimetry, X-ray diffraction, scanning electron microscopy, charge–discharge test, cyclic voltammetry, electrochemical impedance spectroscopy, and gas sensing experiments. Results show that hybrid material exhibits higher capacity, more excellent cycling reversibility, and better sensitivity to ethanol gas than MoO ₃ xerogel.     

Thermal stability of carbon nanotubes

Heat capacities of the carbon nanotubes (CNTs) with different sizes have been measured by modulated temperature differential scanning calorimetry (MDSC) and reported for the first time. The results indicated the values of C _p increased with shortening length of CNTs when the diameters of CNTs were between 60 and 100 nm. However, the values of C _p of CNTs were not affected by their diameter when the lengths of CNTs were 1–2 um, or not affected by the length of CNTs when their diameters were below 10 nm. The thermal stabilities of the CNTs have been studied by TG-DTG-DSC. The results of TG-DTG showed that thermal stabilities of CNTs were enhanced with their diameters increase. With lengths increase, the thermal stabilities of CNTs increased when their diameters were between 60 and 100 nm, but there is a slight decrease when their diameters were less than 60 nm. The further DSC analyses showed both released heat and T _onset increased with the increase of CNTs diameters, which confirms the consistency of the results from both TG-DTG and DSC on CNTs thermal stability.     

Phenylcarbamoylated β‐CD: π‐Acidic and π‐basic chiral selectors for HPLC

Two types of chiral stationary phases for HPLC based on π‐acidic or π‐basic perphenylcarbamoylated β‐CDs were synthesized. The relative structural features of the two effective chiral selectors are discussed and compared in both normal‐phase and RP modes. In addition, the nature and concentration of alcoholic modifiers were varied for optimal separation in normal phase and the structural variation of the analytes was also examined. The results showed that hydrogen bonding, steric effect and π‐acidic–π‐basic interaction contributed greatly to enantioseparation. Upon comparison, some of the differences in the separation behavior of the two types of chiral stationary phases might be due to the π‐acidic or π‐basic phenylcarbamate groups.     

Structure and stability of tube and cage Ge60H60

A tube Ge(60)H(60) isomer in D(5d) symmetry with fused five-membered rings located at the ends of the tube is more stable than the fullerene-like I(h) cage isomer at the B3LYP/cc-pVDZ level of theory. Introducing endo Ge-H bonds increases the stability of both cage and tube isomers. The most stable tube isomer can admit six endo Ge-H bonds. The cage isomer can admit 10-12 endo Ge-H bonds (H(10)@Ge(60)H(50) and H(12)@Ge(60)H(48)), and they also represent the most stable Ge(60)H(60) isomers. The stability order and structural patterns of Ge(60)H(60) are the same as those found for the corresponding Si(60)H(60) isomers. Moreover, it is found that the 6-31G(d,p) basis set fails to predict the relative energies of the Ge(60)H(60) isomers and the Ge(6)H(6) isomers.