Properties and applications of β‐glycosidase from Bacteroides thetaiotaomicron that specifically hydrolyses isoflavone glycosides

To modify the glycan part of glycosides, the gene encoding β‐glycosidase was cloned from Bacteroides thetaiotaomicron VPI‐5482. The cloned gene, bt_1780, was expressed in Escherichia coli MC1061 and the expressed enzyme was purified using Ni‐NTA affinity chromatography. The purified enzyme, BTBG, showed optimal activity at 50 °C and pH 5.5. Interestingly, this enzyme did not have any hydrolysing activity on ordinary β‐linkage–containing substrates such as xylobiose, lactose and cello‐oligosaccharide, but specifically hydrolysed isoflavone glycosides such as daidzin, genistin and glycitin. Compared to a commercial beta glucosidase, BTBG selectively hydrolysed isoflavone glycosides in soybean extract mixture solution. These results suggest that BTBG may be a specialized enzyme for the hydrolysis of glycosides and that the substrate specificity of BTBG is applicable for the bioconversion of isoflavone glycosides in the food industry.     

Area- and time-specific marginal capacity costs of electricity distribution

Marginal costs of electricity vary by time and location. In the past, researchers attributed the variations to factors related to electricity generation and transmission. These authors, however, have not analyzed possible variations in marginal distribution capacity costs (MDCC). The objectives of this paper are:

1. (i) to show that large MDCC variations are due to the dispersion in distribution capital expenditures by time and space,

2. (ii) to propose a method for quantifying the area- and time-specific MDCC in the presence of lumpy investments, and

3. (iii) to compare our MDCC estimates to those commonly used in the electric utility industry.

Our proposed method and its results were adopted by the California Public Utilities Commission (CPUC) in 1992 for Pacific Gas and Electric Company (PG&E), the largest privately owned electric utility in the U.S.     

Effect of Wall Surface Properties at Different Drying Kinetics on the Deposition Problem in Spray Drying

Current methods in alleviating the wall deposition problem in spray drying emphasize mainly controlling the stickiness of the drying particles and less attention is placed on the properties of the dryer wall. In this experimental study, the effect of wall surface properties on the deposition mechanism has been investigated. Properties considered in classifying different wall materials were surface energy, roughness, and dielectric properties. The model solution contained sucrose, representing low-molecular-weight sugars commonly encountered in spray drying of fruit and vegetable juices. The effect of wall properties on deposition was explored at different drying rates producing particles of different surface rigidity. Larger surface roughness produced higher deposition fluxes for particles with high impact velocity and moisture. Surface energy and surface roughness were found to have no significant effect for dry rigid particles at the middle and bottom elevation of the drying chamber. However, material with lower surface energy (Teflon) exhibited less deposition for rubbery particles at such elevations. Analysis shows that dielectric wall material (Teflon) tends to enhance deposition of dry particles because of attrition at the surface. Higher wall temperature was found to produce slightly more deposition. The results of this work give a general indication of the effect of wall material on the deposition problem and provide the fundamental understanding for further studies along this line. Proper selection of dryer wall material will provide potential alternatives for reducing the deposition problem.     

Enhanced direct stiffness method for finite element analysis of textile composites

Traditional homogenization techniques are not useful when the microstructural scale of a material is of the same order of magnitude as the structural scale of a component. Such is the case for many textile composites. Since discrete modeling of the microstructure throughout a component is prohibitively expensive, continuum finite elements are needed which account for the microstructure within a single element. This paper describes a simple substructuring technique for formulating these special elements.     

Serum amyloid P component scintigraphy and turnover studies for diagnosis and quantitative monitoring of AA amyloidosis in juvenile rheumatoid arthritis

OBJECTIVE: To evaluate aspects of the natural history of AA amyloidosis complicating juvenile rheumatoid arthritis (JRA), and its response to therapy with chlorambucil. METHODS: Scintigraphy and 7-day turnover studies were performed in JRA patients with histologically proven (n = 35) or clinically suspected (n = 30) AA amyloidosis, following intravenous injection of 123I and 125I-labeled serum amyloid P component (SAP). Prospective monitoring studies were performed over 2-3 years in 20 patients with amyloidosis. All but 2 amyloidosis patients were treated with chlorambucil. RESULTS: Positive scanning results were obtained in all patients in whom imaging was performed within 12 years of positive biopsy findings of amyloid and in 5 patients with clinically suspected amyloidosis. Negative scanning results with normal SAP metabolism, indicating regression of amyloid, were obtained in 4 patients whose amyloidosis had been in full clinical remission for more than 12 years. Prospective monitoring studies in patients whose JRA-associated inflammatory activity was in remission demonstrated regression of amyloid in 8 patients and no substantial changes in 8 others; however, in 4 further patients with active inflammation, there was accumulation of amyloid. There was a very poor correlation between the amount of amyloid present at a particular site and the resultant organ dysfunction. CONCLUSION: Radiolabeled SAP scintigraphy and turnover studies are useful complementary tools in the diagnosis, screening, and quantitative monitoring of type AA amyloidosis in JRA. The amyloid deposits may progress and/or regress at different rates in different anatomic sites over short periods.     

Compact Dipole Antenna for Terrestrial Digital Multimedia Broadcasting Service

A compact dipole antenna for the terrestrial digital multimedia broadcasting (TDMB) application is presented. The length of the antenna is about 0.06λ at the TDMB resonance frequency of 190 MHz. Miniaturization of the antenna is achieved by using meander structures and lumped elements. The proposed antenna has two resonance frequencies and covers the TDMB band from 174 MHz to 216 MHz in Korea. The antenna has good impedance bandwidth and radiation characteristics for the TDMB. The experimental results of the designed dipole antenna are presented and analyzed.     

High Gd Concentration GaGdN Grown at Low Temperatures

GaGdN layers were grown at temperatures below 300°C by radio-frequency plasma-assisted molecular beam epitaxy on sapphire substrates. GaGdN samples with high Gd concentration as high as 12.5% were obtained by lowering the growth temperature. X-ray diffraction results showed no obvious secondary phase, which means that the phase separation can be suppressed by the growth at low temperatures. All samples, including those grown at room temperature, showed ferromagnetic characteristics. Photoluminescence emission was observed, though spectra exhibit broad and sharp luminescence bands related to many kinds of defects. It is suggested that electrons coming from defects, especially, nitrogen vacancy, stabilize ferromagnetism, and that the carrier-induced ferromagnetism occurs in the low-temperature-growth GaGdN.