Showing papers by "Cairo University published in 1986"

Detection of enteropathogens in fatal and potentially fatal diarrhea in Cairo, Egypt.

Abstract: A 1-year study of the etiology of acute diarrhea complicated by severe (10%) dehydration, active bleeding, shock and cardiovascular collapse, pneumonia, acute renal failure, or seizures in infants under 18 months of age was performed in Cairo, Egypt. Of 145 infants, 19 (13%) died or left the hospital moribund; the remaining 126 patients were classified as having potentially fatal illness. A variety of enteropathogens were identified with approximately equal frequency in the fatal and nonfatal complicated cases as well as in 135 controls with severe uncomplicated diarrhea. The agents most frequently detected in infants with severe diarrhea in this population which were felt to be etiologically important were rotavirus (33%), heat-stable enterotoxin-producing Escherichia coli (20%), heat-labile enterotoxin-producing E. coli (11%), enteropathogenic E. coli (8%), and Salmonella spp. (5%). The high rate of occurrence of Giardia lamblia (35%) probably represented the high carriage rate of the protozoan in this population. Complicated (fatal and potentially fatal) cases differed from control cases in a number of ways: the onset of diarrhea was more sudden, the course was progressive and of greater initial intensity, vomiting occurred more frequently, the patients more often had visited another physician before coming to the hospital, the patients more often had respiratory symptoms and pulmonary abnormalities on auscultation, hypoactive bowel sounds and abdominal distention were more common, as was oliguria, and the patients showed lower mean body weights.

Broad spectrum antifungal agents in otomycosis.

Abstract: The in vitro inhibitory activities of four currently used antimycotic agents (clotrimazole, econazole, miconazole and cyclopirox-olamine) against 304 fungal isolates comprising 51 species from 14 genera of moulds and yeasts, using a serial dilution procedure, were studied. Clotrimazole and econazole were found to have a grossly similar broad-spectrum antifungal activity, inhibiting all the tested yeasts and moulds at a concentration ranging from 0.1-4 micrograms/ml. At this range miconazole inhibited 90 per cent of the strains and cyclopirox-olamine inhibited 57 per cent only and thus they were less effective. Econazole 1 per cent solution was very effective in vivo in the treatment of otomycosis within 1-3 weeks. The drug was well tolerated, with no side-effects. Owing to the high broad-spectrum antifungal activity of clotrimazole and econazole, they should be the treatment of choice in otomycosis and can be used safely as otic drops.

On the simulation source technique for exterior problems in acoustics

Abstract: Pour la resolution du probleme de Dirichlet de l'equation d'Helmholtz, on propose de chercher la solution sous forme d'un potentiel a 1 seule couche acoustique avec une distribution etendue sur une surface interne. Ceci conduit a une equation integrale mal posee de premiere espece qui peut etre approximativement resolue par la methode de regularisation de Tikhonov

Impedance studies of corrosion resistance of aluminium in chloride media

Abstract: The electrochemical behaviour of aluminium in chloride solutions has been studied. Open-circuit impedance measurements reveal that in both acidic and neutral media the dissolution of the oxide formed on aluminium is governed by an empirical relation of the form C m -1 = a − Bt 1 2 where a and B are constants. The rate of the oxide film dissolution in the chloride-containing solutions is found to be markedly lower than that in other halide media, especially in fluoride solutions. The behaviour of the oxide is determined by the pH of the dissolution medium rather than its chloride ion content. Complex plane analysis of the anodic oxide film formed on aluminium indicates that the corrosion resistance is very high in neutral chloride solutions in comparison with acid solutions containing the same amount of chloride ions. Both the charge transfer resistance θ and the Warburg impedance caused by diffusional mass transfer attain markedly higher values in the neutral media which reflect the high passivation properties of the oxide film. It is suggested that many constructions could be coated with aluminium oxide films to protect them from corrosion, especially in marine media.

Gaseous reduction of Fe2O3 compacts at 600 to 1050° C

Abstract: Dense Fe2O3 briquettes were isothermally reduced with hydrogen, carbon monoxide and H2-CO mixtures at 600 to 1050‡ C. The course of reduction was followed by measuring the oxygen weight loss, as a function of time, using a thermogravimetric technique. Microscopic examination, X-ray and carbon analyses were also used to elucidate the kinetics and mechanisms of reduction of Fe2O3 briquettes. In the initial stages of reduction, the highest reduction rate was obtained in hydrogen while the slowest was in carbon monoxide. In CO-H2 gas mixtures, the rate decreased with increasing amounts of carbon monoxide. In the later stages of reduction, a minimum reduction rate was only observed during the reduction with hydrogen and hydrogen-rich gas mixtures due to the formation of denseγ-iron at 900 to 950‡ C. This was eliminated in carbon monoxide and carbon-monoxide-rich gas mixtures due to the carbon deposition in the samples and secondary reactions.

Biochemical Studies on the Essential Oils of some Medicinal Plants

Abstract: Some physical and chemical constants and chemical composition of the essential oils of three Egyptian plants namely thyme, rosemary and sage belonging to the Labiteae family were determined. Gas-liquid chromatographic analysis of thyme, rosemary and sage essential oils indicated the presence of 13, 12 and 8 compounds representing 63.75%, 82.44% and 99% of the total volatile substances, respectively. The most prevalent volatile compounds of thyme, rosemary and sage oils were thymol, α-pinene and thujone, respectively. The anti-microbial examination for these oils against some micro-organisms showed that thyme oil had the greatest effect followed by sage and rosemary oils. Biochemische Untersuchungen der essentiellen Ole einiger Heilpflanzen Es wurden einige physikalische und chemische Konstanten sowie die chemische Zusammensetzung der essentiellen Ole dreier agyptischer Pflanzen, und zwar Thymian, Rosmarin und Salbei, die zur Familie der Labiteae gehoren, untersucht. Die gaschromatographische Analyse der essentiellen Ole von Thymian, Rosmarin und Salbei zeigte die Anwesenheit von 13, 12 und 8 Verbindungen, die jeweils 63.75 %, 82.44 % und 99 % aller fluchtigen Substanzen entsprechen. Die Hauptbestandteile an fluchtigen Verbindungen von Thymian-, Rosmarin- und Salbeiolen waren jeweils Thymol, α-Pinen und Thujon. Eine antimikrobielle Prufung dieser Ole gegen einige Mikroorganismen ergab, das Thymianol, gefolgt von Salbei- und Rosmarinol, den grosten Effekt besas.

Methods of Interval Analysis

Abstract: Three types of errors are encountered in numerical analysis, namely: 1. Round-off errors, arising when numbers are rounded to fit a certain precision arithmetic; e.g. the case where 1/6 = 0.1666 ... is approximated to 0.167 on a three-digit machine. 2. Truncation errors, resulting when convergent series are truncated down to a number of terms, e.g. the case where π = 3.141 592 65 ... is approximated by π= 3.14. 3. Data errors, associated with the specific physical model under study. They represent a parameter’s uncertainties when it is determined through experimental measurements.

Chemical evaluation of rapeseed

Abstract: The seed chemical composition and oil physical and chemical constants of two imported rapeseed German varieties and one locally produced in Egypt were studied. Rapeseeds are characterized by high lipid and protein contents. The fatty acid analysis indicated that palmitic and oleic acids were the most prevalent saturated and unsaturated acids, respectively. Also, the rapeseed oils under study were free from long-chain fatty acids (>C18). The unsaponifiables were fractionated by GLC into 36 different compounds of which 26 hydrocarbons were identified. The hydrocarbons having carbon atoms between C20 and C24 represent the most common compounds. Campesterol, stigmasterol and β-sitosterol were present in appreciable amounts in German varieties while these compounds occurred as trace substances in the seeds produced in Egypt. Chemische Beurteilung von Rapssaat Es wurden die chemische Zusammensetzung der Saat und die physikalischen und chemischen Konstanten des Ols zweier wichtiger deutscher Rapssaatarten und einer Saat aus Agypten untersucht. Die Rapssaaten waren gekennzeichnet durch hohe Lipid-und Eiweisgehalte. Die Fettsaureanalysen zeigten, das Palmitin-und Olsaure die vorherrschenden gesattigten bzw. ungesattigten Sauren waren. Auserdem waren die untersuchten Rapsole frei von langkettigen Fettsauren (>C18). Mittels Gaschromatographie wurde der unverseifbare Teil in 36 unterschiedliche Bestandteile fraktioniert, von denen 26 als Kohlenwasserstoffe identifiziert wurden. Die Kohlenwasserstoffe mit Kohlenstoffatomen zwischen C20 und C24 stellen die haufigsten Bestandteile dar. Bei den deutschen Sorten sind Campesterol, Stigmasterol und β-sitosterol in betrachtlicher Menge vorhanden, wahrend diese Bestandteile bei den in Agypten angebauten Saaten nur als Spuren vorkommen.

Ultrastructure of the salivary glands of the planthopper, Peregrinus maidis (Ashmead) (Homoptera: Delphacidae).

Abstract: The principal salivary gland of the planthopper, Peregrinus maidis (Ashmead) (Homoptera : Delphacidae), comprises 8 acini of only 6 ultrastructurally different acinar types. In these acini, secretory cells contain elongated vacuoles partly lined by microvilli and by microtubule bundles. These vacuoles are apparently connected with extracellular canaliculi deeply invaginated into secretory cells. Canaliculi of each acinus lead to a ductule lumen, which is lined with spiral cuticular intima, surrounded by duct cells. Striated muscle fibers, supplied with small nerve axons and tracheoles, are found in various acini of the principal gland, usually around secretory and duct cells. In the accessory salivary gland, the 2 large secretory cells contain no elongated vacuoles or canaliculi invaginations. However, in their central region, apically, these cells border a large microvilli-lined canal with its own canal cells. This canal is apparently connected with the cuticle-lined accessory duct, formed by duct cells. Nerve axons, but no muscle fibers, are found in the accessory gland and its duct. It is suggested that the system for transporting secretory material within acini of the principal gland, is basically different from that within the accessory gland.

Geometrical structures for cosmological applications

Abstract: A set of conditions for selecting geometrical structures appropriate for cosmological applications is suggested. These conditions are being applied to two geometrical structures constructed mainly for cosmological applications. The algebraic manipulation language REDUCE 2 has been used to carry out the relevant calculations. Without the help of a computer, the calculations involved are very tedious. The results obtained show that one of the two structures should be ruled out as a model for cosmological applications. The combination of the results of the present paper and those of a previous one support the procedure known as ‘The Type Analysis’.

Experimental Investigation of Mixed Laminar Convection in the Entrance Region of Inclined Rectangular Channels

Abstract: The present experimental study considers the effect of combined forced and free laminar convection on the heat transfer in the entrance region of horizontal and inclined rectangular channels under uniform wall heat flux. The test facility includes electrically heated aluminum rectangular channels having aspect ratios AR = 2.667 and 0.375, with water as the working fluid. The experimental results included the circumferential wall temperature distribution and the axial variation of Nusselt number. Correlations of the experimental results of Nusselt number in the fully developed region were obtained in terms of Rayleigh number, Reynolds number, and inclination angle.

Kinetics of the passivation of molybdenum in acids and alkali solutions as inferred from impedance and potential measurements

Abstract: The electrochemical behaviour of mechanically polished molybdenum electrodes in different acid and alkali solutions was investigated using open-circuit potential and impedance measurements. The effect of the concentration of acid (HCl) and alkali (NaOH) on the electrochemical behaviour of the molybdenum electrodes was also studied. The various kinetic parameters, i.e. capacitance, resistance and potential, controlling the mechanism of oxide film growth were monitored as functions of time. Complex plane analysis reflects the high passivation properties of the naturally formed oxide film on molybdenum irrespective of the dissolution medium. The results showed also that the passive films undergo structural changes during the course of measurements which may be attributed to a further oxidation of the passive MoO 2 film to MoO 3 . The electrode potential was found to be sensitive to variations in pH. In highly concentrated NaOH solution, the passive film is subject to continuous dissolution.

Stabilization of discrete systems with multiple-time scales

Abstract: A two-stage method is developed for the stabilization of linear time-invariant discrete systems with multiple-time scales. It is shown that the feedback gains are completely independent. The closed-loop system is asymptotically stable for all sufficiently small singular perturbation parameters which are constrained to be in a bounded set.

The volatile fraction of Senecio glaucus subsp. Coronopifolius

Abstract: The volatile constituents of Senecio glaucus subsp. coronopifolius (Maire Alexander) were investigated by capillary GC-MS of the essential oil obtained by steam distillation and of the headspace. Out of more than 80 volatiles, 30 components, accounting for 90% of the oil, were identified by their Kovats indices on stabilized OV-1 columns and mass spectral data. Chief components of the oil are: myrcene (24%) and dehydrofukinone (I) (21%). (I) was isolated and characterized by UV, IR, 1H-NMR, 13C-NMR and MS. The oil smells apricot-like, while the odour of the intact plant is herbaceous, spicy and floral fruity. (I) is the character impact compound of the oil.

Synthesis and electrical conductivity of AsF5-doped poly(arylene vinylenes)

Abstract: A series of polymers containing 2,5-disubstituted phenylene vinylene units, and the polymer containing 1,4-naphthalene vinylene units, were prepared by polymerization of their bis(sulfonium salts) through a base elimination reaction in solution. Films of these polymers were cast from aqueous solution and chemically treated (doped) with AsF5 vapor. The electrically conductivities of the doped films varied greatly with changes in polymer structure, with the highest value obtained of 1.8 ohm−1 cm−1 for poly (2,5-dimethoxyphenylene vinylene).

Copolymerization of acrylonitrile with N-substituted maleimides

Abstract: Acrylonitrile was copolymerized with three N-arylmaleimides as well as with N-octadecylmaleimide in dimethylformamide (DMF) using azobisisobutyronitrile (AIBN) as initiator. The monomer reactivity ratios were calculated by the Fineman-Ross and the Kelen-Tudős methods from which the Q- and e-parameters of these monomers were evaluated. The prepared copolymers were characterized by viscosity measurements and thermal analysis. The intrinsic viscosity decreases by increasing the maleimide content in the copolymer. Thermogravimetry TG and differential thermal analysis (DTA) data showed a remarkable improvement in the thermal behaviour of the investigated copolymers. A mechanism for the participation of the maleimide units in the nitrile oligomerization was also proposed. The investigation of the dyeing properties of the copolymers with the exception of those containing octadecylmaleimide, showed good affinity towards basic dyes as well as an appreciable improvement in their colour fastness towards UV light. Acrylnitril wurde sowohl mit drei N-Arylmaleimiden als auch mit N-Octadecylmaleimid in Dimethylformamid (DMF) mit Azobisisobutyronitril als Initiator copolymerisiert. Die Copolymerisationsparameter wurden nach Fineman-Ross und nach Kelen-Tudős bestimmt und hieraus die Q- und e-Werte der Monomeren berechnet. Die hergestellten Copolymeren wurden durch Viskositatsmessungen und Thermoanalysen charakterisiert. Die Grenzviskositat der Polymeren sinkt mit steigendem Gehalt an Maleimideinheiten. Die durch Thermogravimetrie (TG) und Differential-Thermoanalyse (DTA) erhaltenen Werte zeigen eine bemerkenswerte Verbesserung des thermischen Verhaltens der untersuchten Copolymeren. Ein Mechanismus fur die Beteiligung der Maleimideinheiten an der Oligomerisierung der Nitrilgruppen wurde vorgeschlagen. Die Untersuchung der Farbeeigenschaften aller Copolymeren mit Ausnahme derer, die Octadecylmaleimid enthalten, ergab sowohl eine gute Affinitat bezuglich basischer Farbstoffe als auch eine recht gute Verbesserung der Farbbestandigkeit gegen UV-Strahlung.

Tribological Properties of PVD Silver Films

Abstract: This paper presents an experimental study made on physical-vapor-deposited (PVD) silver films. A conventional ion plating unit was used in depositing ion-plated, vacuum-deposited, and gas-deposited silver films. Experimental work on nucleation, growth, and interface formation is briefly presented. Some adhesion, microhardness, and x-ray test results are also included. Friction and wear test results are reported in details. The good lubrication properties are attributed initially to the low shear strength in the direction of sliding, and also to the transfer-back-transfer mechanism. The wear mechanism however, is initially a microcutting process, followed by wear debris abrasion process and, finally, a fatigue wear process. Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

Proliferative responses of snake lymphocytes to concanavalin A.

Abstract: Spleen cells (SC) of adult snakes Psammophis sibilans responded to concanavalin A (Con A) in vitro by strong proliferation during the spring and autumn seasons. Con A-mediated mitogenesis was, however, poor in summer and abrogated in winter. Removal of Sephadex G 10-adherent cells from the SC suspensions did not inhibit the lympho-proliferative responsiveness to Con A in spring. This supports the view that the weak responses in summer and winter are essentially due to lack of competent T lymphocytes.

The Least-Squares Problem

Abstract: The set of linear simultaneous equations Ax = b, A ∈ ℝm×n, has either a unique solution for x, more than one solution for x or no solution at all. For x to be unique, A is necessarily nonsingular and x is expressed as x = A−1b (m = n). The situation in which there is more than one solution occurs when b can be expressed linearly in some few column vectors of A having rank equal to r(A) < n. The equations are said to be consistent yet indeterminate. The solution comes as x = A i b, where A i is some generalized inverse of A satisfying AA i A = A. A generalized inverse A i satisfying the latter condition can be easily suggested (Bellman 1970, p. 105) as $$ A^i = P\left[ {\begin{array}{*{20}c}{I_r }\\Y\\\end{array}\;\begin{array}{*{20}c}X\\Z\\\end{array}} \right]R $$ where R and P are respectively elementary row and column operations which bring A to the canonical form, namely $$ RAP = \left[ {\begin{array}{*{20}c}{I_r }\\0\\\end{array}\;\begin{array}{*{20}c}0\\0\\\end{array}} \right] $$ while X,Y and Z are arbitrary. x is therefore given by $$ x = {A^t}b + (I - {A^t}A)c $$ where A t is the determinate part of A i and c is an arbitrary vector accounting for X, Y and Z. To see how this equivalence follows we note that A(I − A t A)= A(I − A i A)= 0 and that AA t b = b, so that premultiplying x by A yields b on the right hand side as our starting assumption. But the vectors of (I − A t A) lie in the null space of A, and a linear combination of them would represent the homogeneous solution.

Prevalence of intestinal parasitic infections in Riyadh district, Saudi Arabia.

Abstract: A total of 23,516 stool specimens collected from patients attending three medical centres in Riyadh, Saudi Arabia, were examined for intestinal parasites. Of these 5737 (24.4%) were positive. Entamoeba histolytica (8.8%) and Giardia lamblia (6.3%) were the commonest parasites found, and in the age group of one to 15 years. Giardia was found in 14.8% of males and 11.9% of females. Other intestinal parasites present included Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni, Hymeolepis nana. Ancylostoma duodenale, Enterobius vermicularis. Taenia saginata and Schistosoma hematotium.

A two-stage output feedback design

Abstract: The problem of output feedback control design for discrete systems with fast and slow modes is considered. It is shown that, when the effect of the slow mode on the fast mode is linearly related to the slow output vector, the control design can be implemented in two stages by using separate gain matrices. The new output feedback design yields first-order perturbations in the behaviour of the discrete system. A ninth-order boiler model is used to illustrate the design procedure.

Effect of hydrocortisone on immune system of the lizard, Chalcides ocellatus III. Effect on cellular and humoral immune responses

Abstract: Administration of a single injection of 1.0 mg/g body weight hydrocortisone acetate (HC) to adult lizards, Chalcides ocellatus in summer elicited a high and lasting rise in serum corticosterone and cortisol, peak levels being, however, in the physiologic ranges of 10 μg% (2×10−7M) and 40 μg% (1×10−6M), respectively. Elevation of serum corticosteroid (CS) concentrations by exogenous HC impaired the proliferative capacity of spleen cells in mixed leukocyte reaction (MLR) and significantly delayed skin allograft rejection. In vivo HC also abrogated the primary in vivo and in vitro immune responses of lizards to rat erythrocytes (RRBC). Reactivity to allogeneic cells in MLR, and antibody production against RRBC were, however, recovered when serum CS levels resumed normal, basal values i.e. at three weeks post-HC injection. These data indicate that rise in circulating CS induces severe immunosuppression in lizards.

Karst landform development and related sediments in the Miocene rocks of the Red Sea coastal zone, Egypt

Abstract: Limestones and evaporites are the main rock types constituting the exposed Middle Miocene sediments of the Red Sea coastal zone between Quseir and Mersa Alam. These rocks represent typical conekarst and karst ridge landforms with minor surface and subsurface solution features. Mechanical, chemical and biogenic precipitates are the main recognized karst sediments. Oxides and sulphides of iron, lead and zinc and barite are also found in association with the karst features and karst products. The obtained observations elaborate the rule of the structure and lithologic characters of the country rocks and the paleoclimatic fluctuation on the formation of the karst features and the related precipitates.