Construction of Protein Probe with a His-tag and an Electron-transfer Peptide for a Target Protein Sensing

A protein probe with an electron-transfer peptide and a His-tag was designed to electrochemically sense a target protein. We selected tyrosine-rich (Y₄C) and tryptophan-rich (W₄C) peptides for use as electron-transfer agents. The peak for oxidation was based on the oxidations of the phenolic hydroxy groups in Y₄C and on the indole rings in W₄C. Asialofetuin (ASF) with galactose residues was the protein probe, and a galactose recognition protein, soybean agglutinin (SBA), was the target protein. A protein probe composed of an amino acid and carbohydrate residue was expected to be biocompatible. When voltammetric measurements were performed using a glassy carbon electrode, the oxidation peaks of H₆Y₄C and ASF-H₆Y₄C appeared at the same potential. The peak current of ASF-H₆Y₄C was 4-fold that of H₆Y₄C because of the stronger adsorption of ASF-H₆Y₄C onto the electrode. The electrode response of ASF-H₆Y₄C with SBA was half that of ASF-H₆Y₄C alone. By contrast, the peak current of ASF-Y₄CH₆ was higher than that of ASF-H₆Y₄C, which was the result of a greater degree of contact between the Y₄C moieties and an electrode. On the other hand, the voltammetric behaviors of ASF with W₄C and a His-tag were similar to those with Y₄C and a His-tag. The sensitivity of SBA using ASF-Y₄CH₆ was at the 10⁻¹³ M level. To confirm the function of the sensing system, measurements were performed in human serum with SBA and ASF-Y₄CH₆. When SBA was added, the serum had a concentration that ranged between 5.0×10⁻¹³ and 4.0×10⁻¹² M, and the amount of SBA that could be recovered ranged from 97 to 101%. Consequently, this system could be applied to the detection of SBA in serum.     

Humidity Effect on Toluene Decomposition in a Wire-plate Dielectric Barrier Discharge Reactor

Laboratory-scale experiments were performed to evaluate the humidity effect on toluene decomposition by using a wire-plate dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure. The toluene decomposition efficiency as well as the carbon dioxide selectivity with/without water in a gas stream of N₂ with 5% O₂ was investigated. Under the optimal humidity of 0.2% the characteristics of toluene decomposition in various background gas, including air, N₂ with 500 ppm O₂, and N₂ with 5% O₂ were observed. In addition, the influence of a catalyst on the decomposition was studied at selected humidities. It was found that the optimum toluene removal efficiency was achieved by the gas stream containing 0.2% H₂O, since the presence of water enhanced the CO₂ selectivity. In addition, the toluene removal efficiency increased significantly in a dry gas stream but decreased with an increase in the humidity when the Co₃O₄/Al₂O₃/nickel foam catalyst was introduced into the discharge area.     

Plasma-catalytic Reactor for Decomposition of Chlorinated Hydrocarbons

The conversion of trichloromethane in mixtures with air was investigated under normal pressure in a gliding discharge (GD) reactor operated in both a homogeneous gas system and with a solid catalyst. The Pt catalyst supported by a honey-comb cordierite structure was placed in the reactor below the ends of the electrodes. Cl₂ and HCl were the main products of the CHCl₃ conversion. The presence of CCl₄ was also noted. The influence of the electrode length and the distance between the electrodes in the narrowest section on CHCl₃ conversion was examined. The Pt catalyst revealed some activity in the trichloromethane processing. This resulted in an increased overall CHCl₃ conversion with the portion of CHCl₃ converted to CCl₄ smaller than that in the homogeneous system. The effect of temperature on CHCl₃ conversion was found to be significant.     

Formation and Thermal Decomposition of Gallium Oxynitride Compounds

The formation of a previously unknown crystalline phase was observed in the system Li–Ga–N–O. During the reactions of Ga₂O₃ with Li₃N and of LiGaO₂ with Li₃N, a new compound with the stoichiometry Li₄GaNO₂ was formed. The stages in thermal decomposition of the new phase were determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

富氧条件下乙炔选择催化还原NOx

Acetylene as a reducing agent of metal exchanged HY catalysts, for selective catalytic reduction of NO in the reaction system of 0.16% NO, 0 （C2H2-SCR） was investigated over a series 08% C2H2, and 9.95% O2 （volume percent） in He. 75% of NO conversion to N2 with hydrocarbon efficiency about 1.5 was achieved over a Ce-HY catalyst around 300 ℃. The NO removal level was comparable with that of selective catalytic reduction of NOx by C3H6 reported in literatures, although only one third of the reducing agent in carbon moles was used in the C2H2-SCR of NO. The protons in zeolite were crucial to the C2H2-SCR of NO, and the performance of HY in the reaction was significantly promoted by cerium incorporation into the zeolite. NO2 was proposed to be the intermediate of NO reduction to N2, and the oxidation of NO to NO2 was rate-determining step of the C2H2-SCR of NO over Ce-HY. The suggestion was well supported by the results of the NO oxidation with O2, and the C2H2 consumption under the conditions in the presence or absence of NO.     

Reduction of NO2 in Flue Gas by CO and Propylene over CuO‐CeO2/SiO2 in the Presence of O2

Catalytic reduction of NO₂ with CO and/or propylene in the presence of NO and excess oxygen, a model mixture for flue gas, was studied over a series of CuO‐CeO₂/SiO₂ catalysts between 120–260 °C. The effect of HCl, an impurity in flue gas, on the activity of the catalysts was evaluated. It was found that a binary oxide catalyst, 2% CuO‐8% CeO₂/SiO₂, was active for the reduction of NO₂ by CO and/or propylene. CO was effective for selective reduction of NO₂ in the presence of NO and O₂ in a temperature window between 160–200 °C while propylene was effective at temperature higher than 200 °C. In the presence of HCl, the activity of the catalyst for reduction of NO₂ with CO was irreversibly deactivated. However, the activity for reduction of NO₂ with propylene was not influenced by HCl.     

Copper-Catalyzed Coupling Reaction of Secondary Alkyl 2-Pyridinesulfonates with Alkyl Lithium-Based Reagents

The Cu(OTf)₂-catalyzed alkyl–alkyl coupling reaction of a secondary substrate MeCH(OSO₂Py)CH₂CH₂C₆H₄(4-OMe) with a nBuLi-based reagent prepared by transmetalation with MgBr₂ ⋅ THF₃ in THF produced a coupling product in 74 % yield. The use of soluble MgBr₂ ⋅ THF₃ in THF was required for this reaction. This method was applied to sBuLi and Ph(CH₂)₄Li. In contrast, transmetalation of MeLi with soluble MgCl₂ ⋅ THF₂ in THF produced the Me reagent, which was reactive for the coupling reaction. The reaction proceeded with inversion of the stereogenic carbon. Furthermore, (S)-14-methyloctadecan-2-one, a sex pheromone produced by lichen moths, was synthesized.     

Field study of the migration of Sr, Nd and Ce in a weak loess aquifer

The migration of Sr, Nd and Ce in a weak loess aquifer was investigated with an Underground Research Facility. Quartz mixed with SrCl₂ ·6H₂O, NdCl₃ ·7H₂O, CeCl₃ ·7H₂O and NaBr was introduced into the aquifer with a stainless steel pipe. The local water flow field in the aquifer was monitored using a 3-dimensional sampling system. A block of the aquifer medium was obtained wholly with a special sampling method and cut into 3-dimensional small pieces (samples) and analyzed. Based on the experimental data, the diffusion coefficients of Sr, Nd and Ce in the aquifer were obtained. This revised version was published online in July 2006 with corrections to the Cover Date.     

Kinetics of carbon dioxide sorption by the composite material K2CO3 in Al2O3

The kinetics of the CO₂ sorption by a composite sorbent K₂CO₃ in Al₂O₃ was studied in a gradientless adsorber at 295 K. The order of the sorption rate with respect to the CO₂ concentration was found to be n = 1.04 ± 0.07. The sorption rate constants were evaluated for sorbent grains of various sizes between 0.25 and 2.1 mm. It was shown that the rate constant is proportional to the grain reciprocal radius. The dynamic capacity was obtained as a function of the CO₂ concentration. The maximum sorption capacity was found to be 83 mg of CO₂ per 1 g of the sorbent. This revised version was published online in August 2006 with corrections to the Cover Date.     

超声化学技术合成MnO2/MoS2纳米交互积层材料

层状氧化锰在氢氧化四甲基胺溶液中超声处理20分钟后，层状氧化锰剥离成纳米层胶体分散液。层状LiMoS₂在超声条件下浸入到10^-4M HNO₃溶液中，随后将得到的处理液加入到层状氧化锰纳米层胶体分散液中，超声处理合成得到了MnO₂/MoS₂纳米交互积层材料，提出了相同电性无机纳米层间超声化学合成新型交互积层材料新技术。     

Investigation of Novel Organometallics by Thermal Spectroscopic Methods

The photolysis of W(CO)₆in CH₂Cl₂ produces (CO)₅WCH₂Cl₂. The high reactivity of (CO)₅WCH₂Cl₂ (1) was exploited to synthesize a vinylidene complexes via the acetylene-vinylidene rearrangement. The addition of a terminal acetylene (H-C≡C-COOCH₃) to a solution of (1) produced the η²-acetylene-pentacarbonyltungsten complex (CO)₅W(η²-HC≡C-COOCH₃) in good yield. The production of the vinylidene complex (CO)₅W=C=CH-COOCH₃in equilibrium with the acetylene complex in the reaction medium was verified experimentally by reaction with excess imine. The heterocyclic organometallic compound of tungsten obtained was separated and purified and its structure was studied by IR, ¹H NMR, ¹³C NMR and mass spectrometry in comparison with the thermal analysis and elemental analysis data. The final aim of this investigation is the development of a new alternative route to a β-lactame with antibacterial activity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chlorobis(pentafluoroethyl)phosphane: improved synthesis and molecular structure in the gas phase

(C₂F₅)₂PCl is now accessible through a significantly improved synthesis protocol starting from the technical product (C₂F₅)₃PF₂. (C₂F₅)₃PF₂ was reduced in the first step with NaBH₄ in a solvent‐free reaction at 120 °C. The product, P(C₂F₅)₃, was treated with an excess of an aqueous sodium hydroxide solution to afford the corresponding phosphinite salt Na⁺(C₂F₅)₂PO^? selectively under liberation of pentafluoroethane. Subsequent chlorination with PhPCl₄ resulted in the selective formation of (C₂F₅)₂PCl, which was isolated by fractional condensation in an overall yield of 66 %. The gas electron diffraction (GED) pattern for (C₂F₅)₂PCl was recorded and found to be described by a two‐conformer model. A quantum chemical investigation of the potential‐energy surface revealed the possible existence of many low‐energy conformers, each with a number of low‐frequency vibrational modes and therefore large‐amplitude motions. The conformer calculated to be most stable was also found to be most abundant by GED and comprised 61(5) % of the total. The molecular structure parameters determined by GED were in good agreement with those calculated at the MP2/TZVPP level of theory; the only significant difference was a discrepancy of about 3° in the C‐P‐C angle, which, for the lowest‐energy conformer, was refined to 98.2(4)° and was calculated to be 94.9°.     

Preparation of TiO2 Sol Using TiCl4 as a Precursor

A titanium dioxide sol with narrow particle size distribution was synthesized using TiCl₄ as the starting material. The sol was prepared by a process where HCl was added to a gel of hydrated titanium oxide to dissolve it. The resulting aqueous titanic acid solution was heated to form titanium dioxide sol. The effects of preparation parameters were investigated. TiCl₄ was slowly added to distilled water at 5°C. Aqueous solution of sodium hydroxide was added to adjust the pH of the system to 8–12. After aging for a period of time, the peptized sol was filtered and sufficiently washed. The filtered cake was repulped in water. Hydrochloric acid was slowly added to the solution with stirring. After condensation reaction and crystallization, a transparent sol with suspended TiO₂ was formed. XRD results show that the crystalline phase was anatase. The suspended TiO₂ particles were rhombus primary particles with the major axis ca. 20 nm and the minor axis ca. 5 nm. The TiO₂ particles prepared at pH 8 had the largest surface area of 141 cm³/g and it was microporous. The compositions of the solution which yielded the smallest suspended TiO₂ particles were TiO₂:HCl (35% HCl) = 1:1 (molar ratio), concentration of TiO₂ = 10%. Hydroxypropyl cellulose with viscosity of 150–400 cps was added as a dispersant. The sol was excellent in dispersibility and long-term stability. Transparent thin films could be obtained through dip-coating glass substrate in the sol. The dip-coating on glass can be less than three times to have one monolayer TiO₂. The transparent TiO₂ thin film had strong hydrophilicity after being illuminated by UV light.     

Characterisation of electroplated Bi<Subscript>2</Subscript>(Te<Subscript>1−x</Subscript>Se<Subscript>x</Subscript>)<Subscript>3</Subscript> alloys

Composition modulated Bi₂(Te_1−xSe_x)₃ thin films were prepared on stainless steel substrates by cathodic electrodeposition. The composition was dependent on the deposition conditions. It was possible to obtain, in the same electrolyte, films with either an excess or a deficiency of bismuth in relation to stoichiometric Bi₂(Te_0.9Se_0.1)₃ by changing the deposition potential or the applied current density. The excess of bismuth was reached at the highest cathodic conditions. The variation of the crystallographic axis and the morphology with a granular structure were correlated with the presence of the Bi enrichment in the ternary. The crystallographic texture of bismuth telluride films was studied according to the electrodeposition conditions. The films presented a fibre texture, and a main orientation {11.0} was observed. Electrical and thermoelectric properties of a Bi_1.98Te_2.67Se_0.39 film were measured and showed an n-type behaviour.     

Activity of Ni catalysts for hydrogen production via biomass pyrolysis

Ni catalysts were tested in the catalytic pyrolysis of biomass. The influence of Ni loading and various catalytic supports (ZrO₂, Al₂O₃, ZrO₂ + Al₂O₃, CeO₂, SiO₂) was studied. Although the gas phase was the main object of this study, solid and liquid residues were tested as well (mainly by TOC and GC-MS methods). Activity tests were performed in a batch reactor with mechanical stirring, equipped with on-line GC. Reaction was conducted at 700°C, with ??-cellulose as a biomass model and with waste paper as an example of raw lignocellulosic material. Reactions in the presence of a catalyst gave a higher hydrogen yield. The most promising results were obtained with Ni/ZrO₂.     

Surface modification of a titanium alloy with a phospholipid polymer prepared by a plasma-induced grafting technique to improve surface thromboresistance

To improve the thromboresistance of a titanium alloy (TiAl₆V₄) surface which is currently utilized in several ventricular assist devices (VADs), a plasma-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) was carried out and poly(MPC) (PMPC) chains were covalently attached onto a TiAl₆V₄ surface by a plasma induced technique. Cleaned TiAl₆V₄ surfaces were pretreated with H₂O-vapor-plasma and silanated with 3-methacryloylpropyltrimethoxysilane (MPS). Next, a plasma-induced graft polymerization with MPC was performed after the surfaces were pretreated with Ar plasma. Surface compositions were verified by X-ray photoelectron spectroscopy (XPS). In vitro blood biocompatibility was evaluated by contacting the modified surfaces with ovine blood under continuous mixing. Bulk phase platelet activation was quantified by flow cytometric analysis, and surfaces were observed with scanning electron microscopy after blood contact. XPS data demonstrated successful modification of the TiAl₆V₄ surfaces with PMPC as evidenced by increased N and P on modified surfaces. Platelet deposition was markedly reduced on the PMPC grafted surfaces and platelet activation in blood that contacted the PMPC-grafted samples was significantly reduced relative to the unmodified TiAl₆V₄ and polystyrene control surfaces. Durability studies under continuously mixed water suggested no change in surface modification over a 1-month period. This modification strategy shows promise for further investigation as a means to reduce the thromboembolic risk associated with the metallic blood-contacting surfaces of VADs and other cardiovascular devices under development.     

Synthesis of Nano‐Sized TiO2 Colloidal Sol and Its Optical Properties

Nano‐sized TiO₂ sol was prepared through a wet synthesis process. The synthesis procedure involved hydrolysis of TiCl₄, acid treatment, and a SiO₂ surface‐modifying process. Before surface modification, the TiO₂ suspension was treated with acid to remove Na ions, soluble TiO_2, and other impurities. The acid treatment of a TiO₂ suspension at a higher temperature was proved to be useful for effective SiO₂ modification. The colloidal sol provided high transparency in visible light as well as excellent UV‐shielding properties. Surface modification of TiO₂ particles with SiO₂ greatly improved both the dispersing stability in neutral pH and the photostability of TiO₂ colloidal sol.     

The origin of enhanced photocatalytic decomposition of ATP on TiO2 powders as induced by surface modification with lanthanide ions: important roles of ATP adsorption to the modified surface

Surface modification of TiO₂ powders with lanthanide salts (EuCl₃ or YbCl₃) enhanced photocatalytic decomposition of ATP. In comparison with the unmodified catalyst, a 3-fold increase in the ATP decay rate was observed with TiO₂ powders as prepared in 5 mM EuCl₃ (or YbCl₃) solution. The reason was ascribed to enrichment of ATP to TiO₂ powder with the lanthanide ions. Evidence was obtained by adsorption experiments where ATP concentration was monitored after dispersing TiO₂ powders into the solution. The ATP molecules adsorbed faster to TiO₂ powder and strongly stabilized there in the presence of Yb³⁺ than otherwise.     

Integration of Succinic Acid and Ethanol Production With Potential Application in a Corn or Barley Biorefinery

Production of succinic acid from glucose by Escherichia coli strain AFP184 was studied in a batch fermentor. The bases used for pH control included NaOH, KOH, NH₄OH, and Na₂CO₃. The yield of succinic acid without and with carbon dioxide supplied by an adjacent ethanol fermentor using either corn or barley as feedstock was examined. The carbon dioxide gas from the ethanol fermentor was sparged directly into the liquid media in the succinic acid fermentor without any pretreatment. Without the CO₂ supplement, the highest succinic acid yield was observed with Na₂CO₃, followed by NH₄OH, and lowest with the other two bases. When the CO₂ produced in the ethanol fermentation was sparged into the media in the succinic acid fermentor, no improvement of succinic acid yield was observed with Na₂CO₃. However, several-fold increases in succinic acid yield were observed with the other bases, with NH₄OH giving the highest yield increase. The yield of succinic acid with CO₂ supplement from the ethanol fermentor when NH₄OH was used for pH control was equal to that obtained when Na₂CO₃ was used, with or without CO₂ supplementation. The benefit of sparging CO₂ from ethanol fermentation on the yield of succinic acid demonstrated the feasibility of integration of succinic acid fermentation with ethanol fermentation in a biorefinery for production of fuels and industrial chemicals.     

ZrO<Subscript>2</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> binary oxides as promising supports for palladium catalysts of hydrodechlorination

Deposited palladium catalysts of the hydrodechlorination of 1,3,5-trichlorobenzene were studied. Pure zirconium and aluminum oxides and ZrO₂-Al₂O₃ mixtures with 1, 5, and 10 mol % Al₂O₃ prepared by coprecipitation were used as supports. Palladium was deposited by the precipitation of its hydroxide on supports. Catalysts on binary supports (ZrO₂ + 1% Al₂O₃ and ZrO₂ + 5% Al₂O₃) exhibited higher activity and stability in hydrodechlorination compared with catalysts on pure supports. The suggestion was made that the high activity and stability of these systems in hydrodechlorination was related to the formation of binary oxide in the interaction of ZrO₂ with palladium oxide at the stage of annealing of the catalyst precursor. Binary oxide, which was a center of the activation of the C-Cl bond, was simultaneously a source of active hydrogen. The presence of various palladium states in catalysts was substantiated by the temperature programmed reduction method.