Browsing College of Arts & Sciences by Publication Date
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Constituents of plants growing in Qatar part XV. Chemical investigation and pharmacotoxicity of pyrrolizidine alkaloids of moltikiopsis ciliata
( Taylor & Francis , 1988 , Article)Chemical study of the alkaloidal constituents of Moltikiopsis ciliata resulted in the isolation and identification of heliotrine and echinatine, in addition to other minor alkaloids. Pharmacological experiments revealed: ... -
Sesquiterpene lactones from Pulicaria sicula
( Elsevier , 1988 , Article)The aerial parts of Pulicaria sicula afforded the known xanthanolides 1-6, the guaianolides 7 and 8 as well as two new ones, the lactone 9 and the corresponding epoxide 10. Furthermore nerylisobutyrate and the thymol ... -
Inhibitory effect of sodium nitrite on corrosion of lead in 0.1 M sodium hydroxide solution
( Council of Scientific and Industrial Research , 1988 , Article)The effect of NaNO2 as an inhibitor for corrosion of lead in 0.1 M NaOH solution has been investigated at different temperatures using the Tafel plot technique. The concentrations of NaNO2 employed are in the range 1-5×10-5. ... -
The Influence of Cation Substitution on the Magnetic Behaviour of Magnesium Ferrite
( WILEY-VCH Verlag GmbH & Co. , 1989 , Article)New polycrystalline specimens of the ferrites Mg1.5Fe1Si0.5O4, Mg1.5Fe1Ge0.5O4, Mg1.5Fe1Ti0.5O4 and Mg1.66Fe1Sb0.33O4 have been prepared and studied by nuclear gamma ray resonance technique, over a wide temperature range. ... -
On the Valence State of Iron in Sr0.52+Ca0.52+Fe0.54+ Me0.54+O32−
( WILEY-VCH Verlag GmbH & Co. , 1989 , Article)Powder samples of Sr0.5Ca0.5Fe0.5Me0.5O3 (Me = Co, Zr or Mn) and Sr0.3La0.7FeO3 are investigated by X-ray diffraction and Mossbauer effect spectroscopy. Analysis of the completely ordered spectra suggested three kinds ... -
Chemical survey of some plants Growing in Qatar
(1989 , Other)Fifty one plants growing in Qatar, belonging to thirty families, were surveyed for alkaloids, anthraquinones, coumarins, flavonoids, tannins and saponins. The medicinal uses of these plants arereported. -
Thiamine-reineckate liquid membrane electrode for the selective determination of thiamine (vitamin B1) in pharmaceutical preparations
( The Royal Society of Chemistry , 1989 , Article)The construction and electrochemical response characteristics of a liquid membrane electrode for thiamine (vitamin B1) based on the formation of an ion pair between the thiamine cation and the reineckate anion in nitrobenzene ... -
Amphetamine Selective Electrodes Based on Dibenzo-18-crown-6 and Dibenzo-24-crown-8 Liquid Membranes
( American Chemical Society , 1989 , Article)Two novel membrane electrodes highly sensitive and selective for amphetaminium cation are developed and electrochemically evaluated according to IUPAC recommendations. These electrodes Incorporate amphetamine-dibenzo-18-crown-6 ... -
Selective determination of thiamine (vitamin B1) in pharmaceutical preparations by direct potentiometric argentometric titration with use of the silver-silver sulphide ion-selective electrode
( Elsevier , 1989 , Article)A simple and selective argentometric titration method is described for determination of thiamine (vitamin B1), based on direct potentiometric titration in alkaline media (⩾0.5M) in which a chemical transformation takes ... -
Liquid membrane electrodes for the selective determination of nicotine in cigarette smoke
( The Royal Society of Chemistry , 1989 , Article)Five liquid membrane electrode systems responsive to the nicotinium cation are described. These electrodes are based on the use of the ion-association complexes of the nicotinium cation with tetraphenylborate, 5-nitrobarbiturate, ... -
Polarization resistance study of inhibition of corrosion of lead by sodium benzoate in 0.1 M sodium hydroxide solution
( Council of Scientific and Industrial Research , 1989 , Article)The effect of sodium benzoate (SB) as an inhibitor of corrosion of lead in 0.1 M NaOH solution has been investigated by using the polarization resistance technique. The concentrations of SB employed are in the range 1-5 × ... -
Inhibitive Effect of Butyltin Trichloride on Dissolution and Localized Corrosion of Aluminium in Sodium Hydroxide and Hydrochloric Acid
( WILEY-VCH Verlag , 1990 , Article)The dissolution of aluminium in sodium hydroxide and hydrochloric acid in the presence of butyltin trichloride as corrosion inhibitor has been studied by hydrogen evolution and thermometric methods. Experimental findings ... -
Vegetation composition of a maritime salt marsh in Qatar in relation to edaphic features
( Blackwell Publishing Ltd , 1990 , Article)Coverpercentage values for plant species were estimated using the line-intercept method along two belt transects starting at the lower mangrove frontier and ending at the upper height of the salt marsh. Twelve perennial ... -
Helminth parasites of fishes from two inland lakes in Egypt
( Nihon Kiseichu Gakkai , 1990 , Article)Results of helminthological examination of 1243 fishes, caught from two inland lakes, with unique and contrasting hydrobiological features at Fayoum Governate in Egypt, are presented. General incidence of trematodes, ... -
A review of process and production in SL studies
( Qatar University , 1990 , Article) -
Constituents of plants growing in Qatar XVII anti-inflammatory and cytotoxic activities of extracts of thirty indigenous species
( Taylor & Francis , 1990 , Article)Thirty plants, indigenous to Qatar, were extracted separately with hexane, chloroform and ethanol. The dried extracts were examined for potential anti-inflammatory activities both in vitro by their ability to inhibit ... -
Guaianolides from Centaurea sinaica
( Elsevier , 1990 , Article & Report)Three sesquiterpene lactones were isolated from the aerial parts of Centaurea sinaica: amberboin, chlorohyssopifolin A and sinaicin. The latter is reported for the first time. -
Constituents of plants growing in Qatar - Part XIX. Flavonoids of Glossonema edule N. E. Br.
( Springer Nature , 1990 , Article)The study of the flavonoids of the unripe fruits of Glossonema edule, resulted in the isolation and identification of apigenin 6,8-di-C-glucoside (violanthin) and luteolin 7-O-glucoside. © 1990 Kluwer Academic Publishers. -
معوقات التنمية الصناعية للقطاع الخاص في دولة قطر
( جامعة الإمارات العربية المتحدة- العين , 1990 , Conference Paper)توجه القطاع الخاص في دولة قطر نحو الاستثمار في القطاع الصناعي بشكل أسرع من ذي قبل بسبب دعوة الحكومة ضمن سياساتها التنموية الجديدة في فترة شهدت ضعفا في الايرادات العامة للدولة بسبب الانخفاض الكبير لأسعار النفط ووصولها الى ...