A Study of the Efficiency in Four Foreign Exchange Markets Using the Survey Data

The purpose of this paper is to reexamine the efficiency condition in four foreign exchange market: U.S.—British, U.S.—Canadian, U.S.—Japanese, U.S.—German. Survey data was used to separate the risk premium arguments from irrationality. Only two markets are considered efficient based on the statistical test: U.S.—Canadian, U.S.—Japanese. Three models were conducted to explain the risk premium which is the factor causing the bias between the forward and the spot rate in the U.S.—German and the U.S.-Japanese markets. Lag Model (Model 2) turns out to be the only model that can explain the risk condition in the U.S.—Japanese market. All the three tested models could to some degree explain the risk condition in the U.S.—German market. Further analysis shows model (la) is the best

Effect of Extreme Acid Combined with Heat Induction on Structure and Properties of Soybean Protein Isolate Microgel

Soybean protein isolate microgel (SPIM) was prepare by extreme acid combined with heat induction. The structural changes and molecular interactions of the protein, and the microstructure and gel properties of the microgel were explored by fluorescence spectroscopy, infrared spectroscopy, and atomic force microscopy, and the effects of different heat induction temperatures (25, 45, 55, 65, 75 and 85 ℃) on the structure and properties of the microgel were evaluated. The results showed that the relative content of β-sheet increased during the formation of SPIM, and electrostatic interaction, hydrophobic interaction and hydrogen bonding were involved in the self-assembly of microgels. In addition, with increasing temperature, the surface hydrophobicity index of SPIM increased first and then decreased, and that the thermal stability gradually increased. Compared with extreme acid, the specific surface area, emulsifying activity, emulsion stability and water-holding capacity of the microgel formed by extreme acid combined with heat induction at 75 ℃ were significantly increased (P < 0.05). Overall, extreme acid combined with heat induction is an effective method to regulate the structure and properties of protein microgels, and the quality of microgels can be improved by precise temperature control

Investigation on Water Vapor Adsorption of Silica-Phosphonium Ionic Liquids Hybrid Material

Adsorption and diffusion of water vapor in phosphonium ionic liquid modified silica gel were studied, aiming to reduce the loading of water vapor in porous materials. The modified silica gel was prepared through a grafting method and characterized by FTIR, thermal gravity analysis and X-ray photoelectron spectroscopy. N2 sorption isotherms at &minus;196 &deg;C and CO2 sorption isotherms at 0 &deg;C were also measured to analyzee the porosity. Water vapor adsorption equilibriums at 25 &deg;C up to 30 mbar were tested. The results indicate that the ionic liquids (ILs) phase acts as a protecting film which decreases water vapor adsorption. The improvement of water-resistant performance is also attributed to the decrease of micro-porosity and silanol groups on the silica surface. Diffusion behavior of water vapor on modified silica was determined on the basis of the adsorption equilibrium. The effective diffusivity of water vapor in modified silica is almost the same as in bare silica and decreases with the increasing of water vapor loading

Evaluation of a carbon nanotube-titanate nanotube nanocomposite as an electrochemical biosensor scaffold

A significant aspect of this work is the development of a multi-wall carbon nanotube (MWCNT)-titanate nanotube (TNT) nanocomposite to serve as a biocompatible scaffold with high conductivity on a biosensor surface. Unlike other scaffolds consisting of MWCNTs alone or TNTs alone, the MWCNT–TNT nanocomposite synergistically provides excellent biocompatibility, good electrical conductivity, low electrochemical interferences and a high signal-to-noise ratio. For comparison, after characterising a scaffold consisting of MWCNTs alone, TNTs alone and a MWCNT–TNT nanocomposite using several spectroscopic techniques, the analytical performance of a horseradish peroxidase (HRP) electrochemical biosensor was evaluated using cyclic voltammetry and differential pulse voltammetry. The scaffold consisting of MWCNTs alone displayed a high background charging current, a low signal-to-noise ratio and distinct electrochemical interference from its surface functional groups. In contrast, the direct electrochemistry and the catalytic capability of HRP at MWCNT–TNT modified biosensors towards H₂O₂ was demonstrated to be ~51% and ~144% enhanced, respectively, compared to those at TNT modified biosensors. Meanwhile, MWCNT–TNT nanocomposite modified HRP biosensors also exhibited higher sensitivity (4.42 μA mM⁻¹) than TNT modified HRP biosensors (1.48 μA mM⁻¹). The above superior performance was attributed to the improved properties of MWCNT–TNT nanocomposite as biosensor scaffold compared to its two individual components by complementing each component and synergistically sustaining the characteristic features of each component.8 page(s

Enhancing direct electron transfer of glucose oxidase using a gold nanoparticle |titanate nanotube nanocomposite on a biosensor

In this paper, we have developed a gold nanoparticle (GNP) decorated titanate nanotubes (TNT) nanocomposite that aids in the direct electron transfer of a large enzyme, such as glucose oxidase (GOD), in which the electroactive site of flavin adenine dinucleotide is deeply buried within the enzyme. The ionic liquid, brominated 1-decyl-3-methyl imidazole, was used to immobilise the nanocomposite and the enzyme on a glassy carbon electrode to further aid in the electron transfer between GOD and the electrode surface. Nafion was also added to anchor the biosensor scaffold. Initially, the tubiform geometry of titanate nanomaterials and the GNP-TNT nanocomposite was confirmed by microscopic and spectroscopic techniques before glucose oxidase was entrapped in the nanocomposite. Based on voltammetric results, this biosensor showed a strong electrocatalytic capability towards glucose (with a heterogeneous electron transfer rate constant of 7.1 s⁻¹ at 180 mV s⁻¹) and the calibration for glucose exhibited a high sensitivity (5.1 μA mM⁻¹) and a wide linear range (0.01-1.2 mM). These results demonstrated superior analytical performance of our biosensor over others fabricated using bulkier TiO₂ nanoparticles or nanobundles, which could be attributed to a high degree of biocompatibility to glucose oxidase and electrical conductivity of the nanocomposite.7 page(s