Browsing Qatar University Science Journal - [From 1981 TO 2007] by Title
Now showing items 712-731 of 770
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Synthesis and Spectroscopic Studies ofAtenolol Derivatives with Enhanced Lipophilicity as Potential Prodrugs
( Qatar University , 2002 , Article)Atenolol, a selective pi-adrenoceptor blocking agent is characterized by its low bioavailability. A number of atenolol prodrugs were synthesized to improve its lipid solubility and hence bioavailability. These compounds ... -
Synthesis And Spectroscopic Studies On Some Ruthenium(II) Complexes
( Qatar University , 1994 , Article)The salt [RuCl2(CO)2ln has proved very useful precursor for the syntheses of a variety of organometallic complexes of transition metals. The compounds of dichlorodicarbonylruthenium(II) of the formula [RuCl2(CO)22L] or ... -
Synthesis Of Some Glycyrrhetic Acid Sulfonamide Derivatives With Prospected Antimicrobial Activity
( Qatar University , 1994 , Article)Some glycyrrhetic acid sulfonamide derivatives (I-VIII) were prepared. Apart from their chemical structures which were confirmed by elemental analysis, IR, 'H and ^C-NMR, their behaviour under electron impact was also ... -
Synthesis of some new oximes, thiocarbamates, pyrazolyloxy, isoxazolyloxy, Pyrmidyloxy and pyridyloxy quinolines
( Qatar University , 1994 , Article)The reaction of 1 or its corresponding chalcones 3a-c with hydroxylamine in boiling pyridine gave the oximes 2 or 5a-c respectively in almost quantitative yield. When both 2 and 5a-c were reacted with phenylisothiocyanate, ... -
Synthesis of some newer indazolyl-oxadiazoles, thiadiazoles and 1,2,4-Triazoles
( Qatar University , 1994 , Article)2-Aryl-3-chloro-2H-indazole (4), obtained in excellent yield (>90%) by the action of thionyl chloride on o-azidobenzanilide(3), was allowed to condense with ethyl p-aminobenzoate to afford the corresponding indazolo-ester ... -
Synthesis, spectroscopic and thermal properties of some ionic polymers and polymeric complexes derived from phthaloyl bis (s-methylhydrazinecarbodithioate).
( Qatar University , 1990 , Article)Mono- and bis hydrzides derived from the condensation of S-methylhyd-razinecabodithioate with benzoylchloride and tere- and iso-phthaloydichloride, respectively, were prepared. Their reactions with secondary ... -
Tail Fracture Planes of Autotomy in Geckos
( Qatar University , 1993 , Article)The structure of the tail facture planes was morphologically and histologically studied in two species of geckoid lizards, living in Qatar, Cyrtodactylus scaber and Bunopus tuberculatus. The fracture plane is formed of a ... -
Tail Regeneration after Autotomy in the Geckonid Lizard Bunopus Tuberculatus
( Qatar University , 1993 , Article)Tail regeneration in the geckonid lizard, Banopus tuberculatus was morphologically and histologically studied after induced atutomy. Seventy percent of the tail of each animal, by length, was removed by autotomy. Regeneration ... -
Tectonic Setting and Petrogenetic Evolution of Wadi Erier Rocks, South Eastern Desert, Egypt
( Qatar University , 2003 , Article)A combination of geologic, petrographic and chemical criteria is used to classify the Erier basement rocks into three suites namely, the metagabbro-diorite (MGD) suite, the tonalite-granodiorite (TG) suite and the ... -
Temperature-salinity structure and mixed layer in the Western Mediterranean Sea
( Qatar University , 1997 , Article)The hydrographic data taken during 1932 — 1985 were analyzed to present the mean temperature structure and the mixed layer in the different basins in the Western Mediterranean Sea. The data indicate that a surface mixed ... -
Theory and Computations for Systems Modeled By First Order Differential Equations
( Qatar University , 2000 , Article)A numerical scheme using Sine functions is developed to approximate the solution of a 2 x 2 system of first order differential equations. The error in the approximate solution is shown to converge exponentially. -
Thermal Acclimation In The Resting Metabolism Of The Nocturnal Gecko, Hemidactylus Flaviviridis
( Qatar University , 1996 , Article)Hemidactylus flaviviridis was acclimated to two temperature regimes (20 and 30°C). The resting metabolic rates (ml g1 h"1) were determined at 20, 25,30 and 35°C, using constant pressure manometric respirometers. The 20°C- ... -
Thermal and Optical Radiation Effects on LEH
( Qatar University , 2003 , Article)Synthetic red blood cells known as LEH is a material that offers an excellent alternative to substitution blood since the chemical composition of the Oxy, LEH, is similar to that of the natural blood cells. Unfortunately, ... -
Thermogravimetry and infrared spectroscopy Of Moroccan oil shales in an oxidative Dynamic atmosphere
( Qatar University , 1994 , Article)Thermogravimetric analyses were carried out on raw Timahdit (Morocco) oil shales and its demineralisation products in an oxidative atmosphere. The kerogen was isolated by successive HCl, HF and float-sink separation ... -
Thermoluminescence (TL) Response Of Gamma-Irradiated Raw Material And The Influence Of Doping By Different Activators
( Qatar University , 1994 , Article)Thermoluminescence of raw materials has been frequently employed to determine the exposure dose as well as effective energy of gamma radiation. In this work, thermoluminescence (TL) properties of cement clinker (C) and its ... -
Thermoluminescence And Dielectric Properties Of An X-Ray Irradiated Double Sulphate Crystal
( Qatar University , 1994 , Article)Thermoluminescence measurements and A. C. conductivity o(w) for nonirradiated and x-ray irradiated Potassium Cesium Sulphate, KCSSO4, crystals have been studied. TL reader type Harshaw model 2000 A+B and the impedance meter ... -
Thermoluminescence induced by gamma radiation In LiCsSO4 Ferroelastic crystal doped With different heavy metals
( Qatar University , 1994 , Article)Thermoluminescence (TL) glow curves of lithium cesium sulphate ferroelastic crystals LiCsSO4 doped with 0.5% of Os, Tb, Eu and Tl have been studied in the temperature range from room temperature to 300"C. Three peaks are ... -
Thermometric Study of Inhibition of Aluminium Corrosion in Hydrochloric Acid Solution
( Qatar University , 1997 , Article)The use of 6- amino - 4- (4-phenyl)-l,4- dihydro -3- methylpyrano [2,3- c] pyrazole -5- carbonitrile and some related compounds as corrosion inhibitors for aluminium in 2 M HCl solution was studied by the thermometric ... -
Threshold Modelling Of Ship's Dynamics
( Qatar University , 1995 , Article)In this paper we consider an application of a system called threshold system in the field of marine engineering. Properties of this system are discussed and the idea of the impulse response function of threshold system is ... -
The Tidal Range And The Observed Sea Level Variations At Alexandria Harbour
( Qatar University , 1994 , Article)On the basis of sea level observations of five years period (1975-1979), the basic properties of the tidal range at Alexandria are described. The problem of the combined effect of tides and meteorological factors on sea ...