Vol. 13 Issue 2

Abdulrahman A. Alwarthan, Fadia H. Metwally and Salma A. Al-Tamimi
A spectrophotometric method is described for the determination of cefotaxime and cefadroxil in various drug formulations. The method is based on the hydrolysis of cefotaxime and cefadroxil in sodium hydroxide that releases hydrogen sulphide, which is then reacted with p-phenylenediamine dihydrochloride in an acidic solution and oxidising the intermediate with Fe (III) ions to give the violet colour. The absorbance of the colour developed is measured at ca. 597 nm for both the drugs. The effect of reagents concentrations and reaction conditions is discussed. The method has been successfully applied to the analysis of some pharmaceutical formulations, particularly of the injection and capsule types.

Mohammed Khair Hourani, Eihab Shamayleh and Kafa Ibrahim
Voltammetric investigations on iodine-coated platinum electrodes revealed their remarkable inertness towards molecular absorption, which means suppression of surface processes, interferences and generally the current background in voltammetric measurements. In the present work, iodine-coated platinum electrodes were prepared by potentiostatic adsorption of iodine at 0.20 V from 1mM KI solution in 1.0 M HClO4. The passive potential window (the working potential range) in 1.0 M HClO4 was approximately from 0.20 to 0.9 V. Electroanalysis of Ag+, Hg2+ and Fe3+ by cyclic voltammetry showed the existence of a linear relationship between the peak current on the E-i curves and the bulk concentration of the ions

Abdel- Aal M. Abdel-Karim and Ashraf F. El-Baroudy
The southwestern part of sinai massif is formed of schist, gneiss and migmatite; a metagabbro-diorite association and granitic rocks. They are dissected by dyke swarms of several different types, ages and styles, including mafic (old) and felsic (young0 suites. The felsic dyke suite is studied in terms of field, petrography and geochemistry. The majority of these dykes trend in the ENE-WSW direction. They range in composition form comendite to alkali rhyolite and true rhyolite, with 73- 81% SiO2 and 3.2- 7.6% K2O. They consist of rhyodacite, rhyolite, quartz porphyry, granite porphyry and granophyre. Porphyritic varieties contain phenocrysts of plagioclase and minor biotite and hornblende. The intrusion of these dyke swarms has occurred during the emplacement of late precambrian younger granites. Chemically, these felsic dykes are peraluminous, enriched in K and their sialic nature suggests a derivation from upper crustal materials. Tectonomagmatic discrimination probably suggests a continental margin environment for these volcanics.

N.H. Malik, A.A. Al-Arainy and J.M. Wadi
In this paper volt-time or V-t characteristics for rod-rod air gaps are determined experimentally using positive and negative standard lightning impulses for gap spacings in the range of 5 to 25 cm. The rods were of cylindrical shape with hemispherical ends and had tip radii in the range of 1 to 5 mm. From the measurements, the effect of rod tip radius, gap spacing and impulse polarity on V-t characteristics is examined and empirical equations for predicting the V-t characteristics of short sir gaps are proposed. The values of breakdown voltage predicted by the proposed equations are compared with measurements reported in the literature and a good agreement is observed between the two sets.

Ali K. Yousif, Ian D. Morton and Abdelmnoeim I. Mustafa
Light (LM) and scanning electron (SEM) microscopy were used to follow the changes that occur during dough mixing and baking and to compare the structure of wheat and mixed wheat- date paste doughs and bread. Date paste (4, 8 and 12%) was used as a martial replacement for wheat flour in the bread dough formula. The well developed gluten protein in doughs containing 4% date paste or 3% sucrose were identified by microscopic examination. Rupture and discontinuities in the 12% date paste supplemented doughs were also apparent. Crumb examinations indicated gelatinization. The association between starch and gluten protein and the liberation or separation of the starch granules from the protein matrix could be seen. Whereas adding 4% date paste to the bread formula improved the bread crumb structure. 12% paste had an adverse effect.

Saeid Basmaeil and Mohamed H. Tolba
Seven experiments in total with three replicates per experiment were conducted to determine the heat and moisture produced and efficiency of feed utilization for growing dairy heifers and sheep under actual production conditions. Total heat production for dairy heifers was linearly decreased from 278 to 152 Watt/100 kg as they grew from 98 to 305 kg. The decrease of total heat produced for sheep, on the other hand, was from 10 to 4.3 Watt/kg as they grew from 20 to 53 kg. Heat loss by evaporation represented an average of 37% and 68% of the total heat produced by heifers and sheep respectively. Linear regression equations were developed to predict the heat losses as function of animal body weight. The effect of body covering or fleece thickness on sheep heat losses were also studied. The percent of sensible heat loss to the total heat loss increased from 14% to 52% as fleece were sheared from 9 to 0.4 cm. Growth rate and feed efficiency were also determined. The feed efficiency decreased from 0.41 to 0.11 as heifers grew from 98 to 305 kg, while the drop was from 0.33 to 0.16 as sheep grew from 20 to 53 kg.

A.A. Al-Hendi
A soil fertility survey was conducted over two years in two major agricultural regions in Saudi Arabia. Four centre pivot fields representing Hail and Tabuk sites were chosen. Effect of intensive application of chemical fertilizers used for wheat production on soil chemical properties was studied. Soil test levels of P, K, Fe, Zn, Mn and Cu were determined. The results show that there is considerable P accumulation in the surface layers of all fields under investigation; whereas the K content of the soils is decreasing. Mn build up in the surface layers of all the fields has also been observed.

H.A. Bokhary and Sarwat Parvez
Fungi were isolated from different types of soils in Saudi Arabia using three different media. Their ability to utilize edible oil as a sole carbon was then examined. Out of a total of 74 fungal species isolated, 29 could utilize edible oil as the sole source of carbon. Initiation of growth was shown by some fungi in a dox medium containing edible oil and sucrose as carbon sources but these fungi failed to grow on the medium containing edible oil as the only carbon source.

Sania A. Kamal and Salama M. El-Darier
The objective of this study is to construct a vegetation cover map and to quantify the different levels of human pressures upon land resources in the habitat of inland plateau at El-Hammam sector. The study revealed that overgrazing represents about (77.6%) while crop and orchard cultivations form 22.4% of the area. Species rated as dominants and codominant in the present study were: Anabasis articulata, Thymelaea hirsuta, Plantago albicans, Noaea mucronata and Scorzonera alexandrina. It was found by using spot image that 25.7 km^2 of El-Hammam inland plateau to be completely destroyed; all woody species are suffering from eradication and the surface appears bare and disturbed due to urban land use

Abdul-Karim J. Sallal
Effect of Kuwait crude oil and benzene on growth, photosynthesis and glycollate dehydrogenase of Anacystis nidulans were studied. Crude oil completely inhibited growth, photosynthesis and enzyme activity at a concentration of 4 ml/l. However, benzene had its complete inhibitory effect at about 0.4 ml/l