ANTIOXIDANT ACTIVITY OF WHEAT CARYOPSES AND EMBRYOS EXTRACTS

Phenolic compounds were extracted with 80% methanol from caryopses and embryos of wheat (cv. Alba and Elena). In extracts the content of total phenolics was determined and UV spectra recorded. For all extracts the antioxidant activity in a β-carotene-linoleate model system, scavenging effect on DPPH radical, and reducing power were examined. Extracts of wheat embryos were characterized by a higher content of total phenolics. UV spectra of phenolic compounds extracted from wheat caryopses were characterized by maxima close to 320 nm due to phenolic acids, and by maxima at shorter wavelengths (272–280 nm) attributed to other phenolic compounds. The antioxidant activities of extracts from caryopses in a β-carotene-linoleate model system were higher than those from embryos. The results so obtained were similar to those observed previously for extracts of rye and triticale grains and leguminous seeds. The scavenging effect of wheat extracts on DPPH radical and their reduction power were weak, but those for embryos extracts were somewhat stronger.     

Tetragonal to monoclinic transformation and microstructural evolution in ZrO2–9.7 mol% MgO during cyclic heating and cooling

The tetragonal (t) to monoclinic (m) transformation behaviour and its relationship to microstructural evolution were investigated by means of dilatometry and transmission electron microscopy for ZrO2–9.7 mol% MgO during cyclic heating and cooling between room temperature and 1490 K. In the as-sintered specimens, fine oblate ellipsoidal t-phase precipitates, 20–50 nm in diameter and 100–200 nm long, were distributed in the cubic (c)-phase matrix. They were below a critical size for transformation and exhibited no transformation in the first three cycles. In the fourth and further cycles, transformation occurred in two distinct stages. A low-temperature stage appeared at 850–1000 K on heating and at 400–700 K on cooling, while a high-temperature stage appeared at 1350–1400 K on heating and at 1000–1200 K on cooling. With the increasing number of cycles, at first the size of low-temperature stages increased and then decreased above ten cycles accompanying the development of the high-temperature stage. During cyclic heating and cooling, coarsening of ellipsoidal precipitates and decomposition of c- and t-phases occurred. As a result of the decomposition, MgO particles and a new m-phase containing a very low concentration of MgO were produced. The coarsened ellipsoidal t-phase precipitates were responsible for the low-temperature stage. The new m- or t-phase containing very low MgO produced by the decomposition was responsible for the high-temperature stage.     

Interfacial structures and mechanical properties of steel–Ni and steel–Ti diffusion bonds

Static and fatigue shear tests of steel–Ni bonds and steel–Ti bonds were carried out to obtain the relations between the strengths and the bonding conditions. Ultrasonic measurements were also made to examine the relations between the strengths and the size of the bonded region (the estimated diameter). At the bonding interface of the steel–Ni bonds, no intermediate phase was observed. At the bonding interface of the steel–Ti bonds, a thin layer of intermetallic compound was formed at lower bonding temperatures but, at higher bonding temperatures, the interlayer melted and the bonding interface became rough. The intensity of the ultrasonic wave reflected from the bonding interface changed, depending on the state of the bonding interface. In shear tests of the steel–Ni and steel–Ti bonds, cracks propagated along the bonding interface, and the strength was proportional to the square of the estimated diameter. In fatigue tests, cracks propagated in the thickness direction of the plate and no relation was obtained between the fatigue life and the estimated diameter. Fatigue life distributions were represented by two- and three-parameter Weibull distributions. This revised version was published online in November 2006 with corrections to the Cover Date.     

Ethylene Absorbent to Maintain Quality of Lightly Processed Fruits and Vegetables

Ethylene had an undesirable effect on the quality of kiwifruits, bananas, broccoli, and spinach leaves that were prepared and stored as lightly processed products. A 2.or 20 ppm ethylene treatment hastened the softening of the pulp of kiwifruits and bananas held at 20°C. Use of charcoal with palladium chloride, as ethylene absorbent, prevented the accumulation of the ethylene and was effective in reducing the rate of softening in kiwifruits and bananas and of chlorophyll loss in spinach leaves, but not in broccoli.     

Structure of Borate Glasses

Anomalous thermal expansion and other properties of borate glasses have previously been given a structural explanation by Abe. This explanation is here reinterpreted and revised in terms of the structon theory of Huggins. In agreement with Warren, it is postulated that, in glasses containing, in addition to boric oxide, small relative amounts of an alkali or alkaline-earth oxide, some of the boron atoms are surrounded by four oxygen atoms and all the oxygen atoms bridge between two boron atoms. At concentrations beyond that of the thermal expansion minimum, some oxygens are assumed to have only one boron neighbor. These ideas are formulated quantitatively and are used to interpret pertinent experimental data. From the concentrations where the property-composition curves show breaks, conclusions may be drawn as to the average number of oxygens surrounding each metal atom.     

Effects of storage temperature and water activity on the survival of bifidobacteria in powder form

Effects of water activity and storage temperature on survival of bifidobacteria in powder form were investigated and kinetic analyses were performed to reveal characteristics of the stability. A significant positive correlation was observed between water activity and natural logarithm of the inactivation rate constant of bifidobacteria powder, indicating that higher water activity induced lower stability of bifidobacteria in powder form. Also, higher temperature condition induced lower survival rate, which was supported by that the stability was followed the Arrhenius theory. These findings constructed a prediction model for bifidobacteria survival in powder form.     

Circle condition and stability margin of the optimal regulator for systems with delays

Robustness properties of the optimal regulator for systems with delays in the state are characterized: first, a Nyquist stability criterion is developed and the circle condition of the optimal regulator is derived. On the basis of these results, the stability margin of the optimal regulator is evaluated as by Lehtomaki el al. (1981), and it is shown finally that the stability margin is equal to that in the finite-dimensional case     

Power generation scheduling by neural network

A new method for solving a power generation scheduling problem in an electric power system is presented. The objective is to determine the hourly start-up/ shut-down schedules of all generators so that forecasted hourly power demands per day may be met and total operating costs, the sum of setup and fuel costs for a given day, may be minimized. The problem may be formulated as a large-scale combinatorial optimization problem which includes 0-1 variables representing the start-up/shut-down of generators and continuous variables representing the power outputs. Determination of an optimalsolution within practical time limits is consequently difficult. Until now, the lagrangian relaxation method has been studied as it appeared to be the most practical method for obtaining an approximate solution to the problem. The efficiency of this method, however, depends on how the Lagrange multipliers are determined. Here, it is proposed that the Lagrange multipliers be estimated by utilizing the neural network and results determined from examination of the possibility of applying the backpropagation algorithm to pattern recognitions which presume the relationship between power demand pattern and Lagrange multipliers are reported. Through numerical experiments, it was established that the Lagrange multipliers, estimated by the neural network, are applicable to the problem.     

Comparative Studies on the α and α-Phosvitin from Hen's Egg Yolk

Physico-chemical properties of α and β-phosvitin were compared. Considerable difference was observed in amino acid composition. Higher concentrations of carbohydrates were found in the β-component than in α. The α-phosvitin was more precipitable with lo-15 mM Ca ion than β. Phosvitin was so heat resistant that no change was observed on electropherogram by heating below 100°C for 10 min, and no coagulation occurred up to 140°C. About 12% of the phosphorus was liberated from whole phosvitin by heating at 140°C for 10 min. All preparations of phosvitin isolated from six individual eggs and mixed yolk of 57 eggs contained the two components.     

Quality Improvement and Evaluation of Hypoallergenic Rice Grains

The color of hypoallergenic rice grains, produced by an enzymatic process was improved by treatment with diluted hydrochloric acid and washing with water. The acid-treated grains were steamed at the surface layer to prevent breakage. Textural evaluation showed the cooked hypoallergenic rice grains had a favorable stickiness/hardness ratio.