Recombinant expression and characterization of N-acetylglucosaminyltransferase I derived from Nicotiana tabacum

The C-terminal catalytic domain of tobacco N-acetylglucosaminyltransferase I fused to maltose-binding protein was produced in Escherichia coli as a soluble form with significant activity. The protein was affinity-purified using amylose resin, and its enzymatic properties were investigated, including its divalent cation requirements, optimal temperature, optimal pH, and substrate specificity.     

Catalytic Performance of Metal Nanoparticles Supported by Ceramic Composite Produced by Partial Reduction of Solid Solution with Dopant

A composite with well-dispersed metal nanoparticles at a ceramic surface was produced by partial reduction of solid solution. It was found that a small amount of dopant, such as Al₂O₃, Cr₂O₃, or Sc₂O₃, accelerated the precipitation of the metal nanoparticles during the reduction. Catalytic performance of the composite for methanol reforming was evaluated. In the Ni-based catalysts, the dopant decreased the CO production by promoting a methanation reaction, while in the Co-based catalysts, the dopant did it by inducing a water–gas shift reaction. Co/MgO with Sc₂O₃ doping showed the most preferable reforming performance, high H₂ production, and CO₂ selectivity.     

Bacteriolysis by vancomycin-conjugated acryl nanoparticles and morphological component analysis

Nanoparticles are currently attracting considerable attention because of their ability to conjugate to various substances. As such, these nanoparticles can assist the transfer of the conjugated substance to target tissues where they are gradually released. In this study, vancomycin-conjugated nanoparticles (VCM NPs) were prepared. The antibacterial activity of VCM NPs was compared with that of VCM alone by exposure to vancomycin-resistant enterococci (VRE). The morphology of the cells was then analyzed by electron microscopy. VCM NPs were found to have more potent antibacterial activity against VRE compared to VCM alone, but the activity against vancomycin-sensitive enterococci (VSE) remained the same. The antibacterial activity of nanoparticles alone was the same against VSE and VRE. The nanoparticles were found to induce characteristic morphological changes in the bacteria based on scanning and transmission electron microscopy. The results suggest that the strong antibacterial activity of VCM NPs against VRE may be attributable not only to the well-known control release carrier property of the nanoparticles but to an additional mechanism that involves VCM NPs avoiding the drug resistant mechanism of VRE.     

Strength of β-sialon/Si3N4 layered composites

The strength of layered composites consisting of -sialon and Si3N4 layers, which were prepared by hot pressing, was investigated. The strength increased as the thickness of the sialon (outer layer) decreased, and reached almost the same level of Si3N4 (inner layer) when the sialon thickness was 250–300 m. No specific fracture morphologies were recognized around the interface of sialon and Si3N4. The aluminium concentration changed sharply around the interface, while the yttrium tended to diffuse deeper than aluminium. This tendency was remarkable in the samples hot-pressed at higher temperature (1900°C). The existence of compressive residual stress in the surface sialon layer was revealed and the residual stress increased as the sialon thickness decreased down to 250–300 m. The increase of strength with the decrease of sialon thickness was discussed based on the mechanical calculations in which the residual stress was considered. This calculation approximately agreed with the results of the samples hot-pressed at lower temperature (1800°C). However, the strength of the samples hot-pressed at 1900°C was much higher than the prediction in the thin range of the sialon thickness. The deep diffusion of yttrium into the sialon layers was thought to be one of the causes of this unpredictable effect.     

Characteristics and oil absorption of deep‐fat fried dough prepared from ball‐milled wheat flour

BACKGROUND: High levels of oil in fried products has been recognized as causing health problems. The formation of microstructure during frying is one factor that influences oil absorption. Above the glass transition temperature (T_g), the physical properties of a polymer influences the formation of structure. The ball‐milling process changes the physicochemical properties of wheat flour constituents. The present study investigated the effects of physicochemical changes in wheat flour by the ball‐milling process on structure formation and oil absorption in wheat flour dough model. RESULTS: Dough samples were made from wheat flour that had been ball‐milled for 0 to 10 h and then fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration, and textural properties of fried samples were evaluated. As compared with samples made of non‐milled flour, samples made from milled flour had smaller pores and higher oil absorption. The fracture force of a fried sample prepared from non‐milled flour was lower than that of a sample prepared from milled flour. CONCLUSION: Ball‐milling affected the microstructure formation in fried wheat flour dough, and subsequently oil absorption. The crispness of a sample prepared from non‐milled wheat flour is higher than that of a sample prepared from ball‐milled wheat flour. This may be due not only to a plasticization effect, but may also be dependent on microstructure. Copyright © 2008 Society of Chemical Industry     

Equations for spectrophotometric determination of relative concentrations of myoglobin derivatives in aqueous tuna meat extracts

The percentage of metmyoglobin (%metMb) in aqueous meat extracts of bigeye and bluefin tuna and beef samples were estimated using previously reported equations derived from the absorption spectra of horse Mb. The results demonstrate that in an aqueous extract, the difference in %metMb estimated by the different equations was negligible for beef samples. Conversely, in an aqueous tuna extract, different %metMb values were obtained with the different equations. The discrepancy in the tuna sample results might be due to differences in absorption spectra for horse and tuna Mb. Therefore, a new set of equations derived from the absorption spectra of bigeye tuna Mb, reported by Matsuura and Hashimoto (1955), was established. The accuracy of the proposed equations was compared with the cyanmetmyoglobin (cyanmetMb) method. The results show that the total Mb concentrations estimated by our proposed equations were in good agreement with the results obtained by the conventional cyanmetMb method (R² = 0.984). Therefore, the new set of proposed equations is valid for the spectrophotometric determination of the relative proportions of Mb derivatives and total Mb concentration in aqueous tuna meat extracts.     

Studies on syntheses and permeabilities of special polymer membranes. XIV. Permeation characteristics of modified nylon 12 membranes

The permeation characteristics and the burst strength of nylon 12 membranes treated with heat in various solutions such as aqueous solutions of formic acid, formic acid/formalin, and sodium hydroxide/ formalin were investigated under various conditions. They were significantly influenced by the treatment solution, temperature and time, and the concentration of acid and alkali in the treatment solution. In particular, nylon 12 membranes treated with formic acid/formalin remarkably improved the permeation characteristics and the burst strength. These phenomena were discussed from the standpoint of the effective pore size and pore number in the membrane, and the form and aggregation of polymer molecules forming the membrane.     

Component spatial pattern analysis of chemicals by use of two-dimensional electro-optic terahertz imaging

We demonstrate a method of chemical mapping by using the transillumination terahertz (THz) images obtained by two-dimensional electro-optic THz imaging. The images and spectral data were measured between 0.1 and 1.0 THz. An experimental sample consisting of three chemicals was prepared, with one in two concentrations. By introducing the component spatial pattern analysis based on the least-squares method, the chemical composition, spatial distribution, and difference in concentration were clearly determined.