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Now showing items 21-30 of 40
A short critique of the Crescent English Course
(
Qatar University
, 1988 , Article)
This paper is a short critique of the "Crescent English Course", Pupils Book 2. It falls into two parts. The first is information about the course; its aims, organization and some of its general characteristics. The second ...
A study of the interlanguage of some Arabic students of English
(
Qatar University
, 1988 , Article)
In this study, the contrastive analysis method is used to investigate the lnterlanguage (IL) developmental sequences of the acquisition of some aspects of English by Arabic-speaking learners. The learners, whose language ...
M-Profile ray tracing technique for multipath propagation
(
IET
, 1987 , Article)
A model for the modified refractivity is suggested and used in a new and simple ray tracing approach for multipath propagation. The technique is then used to study the variations in ray path parameters for different path ...
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: ...
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 ...
Constituents of plants growing in Qatar VII an examination of certain plants for anti-inflammatory activity
(
Taylor & Francis
, 1985 , Article)
Six desert plants native to the State of Qatar were successively extracted with hexane, chloroform and ethanol. These extracts were examined for their ability to inhibit aggregation of rabbit blood platelets induced by ...
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, ...
Constituents of plants growing in Qatar IX. The antispasmodic components of cymbopogon parkeri stapf. Parkeri stapf
(
Taylor & Francis
, 1986 , Article)
Investigation of the lipid fraction of Cymbopogon parkeri revealed the presence of several active constituents, one of which possesses an antispasmodic activity and was identified as cryptomeridiol. Study of the other ...