Quality of Five Rice Varieties Grown in Egypt

The quality of two new drought-resistant varieties of rice (IR441 and IR3304) grown in Egypt, were compared with three commercial varieties (Selection 180, Reiho and Giza 172). Based on milling yield, IR441 and IR3304 showed lowest rice quality. Gelatinization temperature was highest in IR441 and lowest in IR3304 and Giza 172. During cooking, water uptake ratio and elongation ratio were higher in IR441 and Selection 180. Protein content was in the range 4–6% for all varieties. Amino acid analysis indicated nutritional superiority of Selection 180 over the other varieties. With the exception of lysine and threonine, the amount of each of the other essential acids in IR441 and Reiho matched or exceeded the FAO/ WHO pattern. IR3304 is deficient in the most number of essential acids (lysine, threonine, and isoleucine).     

ELECTROMAGNETIC TRANSIENTS ON COMPENSATED LINES UNDER CORONA

ABSTRACT

The purpose of this paper is to present a digital computational method for the determination of the fast electromagnetic transients propagating on compensated overhead power lines, evoked by internal or external over voltages, as effected by corona discharges. The approach enables the consideration of series capacitor and shunt reactor compensation. The line model is based on time-domain solution using the Runge-Kutta-Verner numerical technique to solve a set of simultaneous differential equations, whose number depends on the assumed number of line sections, as derived from the line equivalent circuit. The increase of the location-dependent conductor effective radius due to corona is considered as one of variable sets, using an iterative solution procedure. To avoid the parasitic Gibbs-oscillations due to the finite number of line sections (which are superimposed on the actual solutions, a set of properly chosen damping resistors is added to the line model, yielding a frequency-dependent damping. The simulation of the corona discharge uses a model derived from an experimentally measurable voltage-charge hysteresis loop relationship of a line test length. As far the input voltage stimuli are concerned, so the model can consider any voltage-time function (step, ramp, double-exponential, sine waves...etc), or even be in the form of tabulated numerical data. The validity of the model is checked by comparing its results to corresponding measurements.     

DETECTION OF FIMBRIAE (CFA/I) ON ENTEROTOXIGENIC ESCHERICHIA COLI USING ANTIBODIES

Fimbriae (CFA/I) were isolated after detachment from an enterotoxigenic Escherichia coli ( ETEC) strain H10407, purified by successive isoelectric point precipitation at pH 3.5, and injected into rabbits. The antisera containing the polyclonal antibodies against the fimbrial proteins (antigens) were then used to detect the presence of CFA/I on other E. coli cultures using an indirect ELISA system. The ELISA procedures for the CFA/I assay was as sensitive as the DNA hybridization for detecting the ETEC strains. Two bands (major and minor) were present when the isolated fimbrial proteins were subjected to SDS-PAGE. The major band had a molecular mass of 40.3 and the minor 36.4 kDa. Electron microscopy of the fimbriae appeared as thin thread rods with variable length (5–15 μm ).     

OPTIMAL COMPENSATION OF NONUNIFORMLY LOADED RADIAL FEEDERS,WITH APPLICATIONS

ABSTRACT

This paper presents a generalized mathematical model for assessing the loss reduction in nonunlformly loaded radial feeders by capacitor shunt compensation. The model allows for the simultaneous presence of linearly increasing feeder load density in addition to a concentrated load at the feeder end. Any number of compensating capacitors can be included in the analysis. The model is then applied to study the effect of the number of feeders on the achieveable optimal reduction in the feeder copper loss. The paper also gives the optimal size and locations of these capacitors, for any number of radial feeders eraenatlng from a distribution substation to serve a certain total load.     

Libyan Date Syrup (Rub Al-Tamr)

Representative samples of date syrup were obtained from the local market and analysed. The chemical composition and some characteristics of these samples were investigated. The reducing sugars of the syrup comprised about 95% of its total sugars content. The major sugars present were glucose—48.70%, fructose-45.21%, and sucrose—6.09%. Furthermore, the coloring matters of date syrup were isolated, separated and further investigated. It was concluded that the color groups, degradation products of reducing sugars, melanoidines, and iron-polyphenolic complexes, contributed to the color of date syrup. The melanoidine-type compounds, which comprised the major part of syrup colorants, showed a low selective adsorption tendency on both charcoal and anion resins. An efficient clarification of date syrup has been achieved by the use of calcium phosphate precipitation. The results obtained may be of help in devising industrial processes for the utilization of dates, abundantly grown in Libya, in the production of “Total invert liquid sugar” with multiple commercial uses of its own.     

Detection of Enterotoxigenic Escherichia coil in Foods by DNA Colony Hybridization

A DNA colony hybridization procedure was used to identify and enumerate a heat-labile toxin-producing strain of Escherichia coli (H10407) in various types of foods. Foods were seeded with H10407 cells and examined by DNA hybridization on nitrocellulose filters with ³²P- labeled heat-labile toxin gene fragments. The number of cells recovered on plate count agar and eosine methylene blue agar was compared. With nitrocellulose filters, recoveries were about 81% on plate count agar and about 76% on eosine methylene blue agar. No significant differences in recovery were observed with ten different food types.     

Biosynthesis of raw starch degrading β-cyclodextrin glycosyltransferase by immobilized cells of <i>Bacillus licheniformis</i> using potato wastewater

The study was sought to enhance the synthesis of thermal stable β-cyclodextrin glycosyltransferase (β-CGTase) using potato wastewater as a low-cost medium and assess the degree to which it is efficient for industrial production of β-cyclodextrin (β-CD) from raw potato starch. Thermophilic bacteria producing β-CGTase was isolated from Saudi Arabia and the promising strain was identified as Bacillus licheniformis using phylogenetic analysis of the 16S rRNA gene. Alginate-encapsulated cultures exhibited twice-fold of β-CGTase production more than free cells. Scanning electron microscopy (SEM) of polymeric capsules indicated the potential for a longer shelf-life, which promotes the restoration of activity in bacterial cells across semi-continuous fermentation of β-CGTase production for 252 h. The optimal conditions for β-CGTase synthesis using potato wastewater medium were at 36 h, pH of 8.0, and 50°C with 0.4% potato starch and 0.6% yeast extract as carbon and nitrogen sources, respectively. The purified enzyme showed a specific activity of 63.90 U/mg with a molecular weight of ∼84.6 kDa as determined by SDS-PAGE analysis. The high enzyme activity was observed up to 60°C, and complete stability was achieved at 75°C. High levels of activity and stability were shown at pH 8.0, and the pH range from 7.0–10.0, respectively. The enzyme has an appreciable affinity for raw potato starch with a Km of 5.7 × 10⁻⁶ M and a Vmax of 87.71 µmoL/mL/min. β-CD production was effective against 25 U/g of raw potato starch. The outcomes demonstrated its feasibility to develop a fermentation process by integrating the cost-effective production of β-CGTase having distinctive properties for β-CD production with ecofriendly utilization of potato wastewater.     

STUDIES ON LIBYAN HONEYS

Ten honey samples representing various floral types were obtained from different areas in Libya. Two other samples were obtained from hives, where bees were fed on sugar syrup and date syrup, respectively. The chemical composition and some characteristics of these samples were studied. The data obtained generally showed that the specifications of honeys produced in Libya conformed with those required for table honey. The application of thin-layer chromatography on cellulose-coated plates for the analysis of honey sugars yielded clear resolution and discrete spots. Some measures — such as high level of calcium, low level of potassium and UV-absorption spectra of honeys were suggested to be used for identifying the sugar-honeys and for ensuring the quality of blossom honeys. An attempt has been made to predict the granulation behavior of honeys and a derived regression formula was suggested.