Browsing Qatar University Science Journal - [From 1981 TO 2007] by Title
Now showing items 115-134 of 770
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The Complexation of Lanthanides by Azo-B-Diketones Stability Constants
( Qatar University , 1982 , Article)The stability constants of the complexes between the trivalent lanthanide series of cations and series of azo-B-diketone ligands are reported. The measurements were conducted at 30°C and zero ionic strength (free KN03), ... -
Concentration of Some Heavy Metals in Short Cores in the Nearshore Sediments of Alexandria , Egypt
( Qatar University , 2006 , Article)The Western Harbor, Eastern Harbor and Abu Qir Bay are three sites located along the Alexandria coast. These sites are characterized by extensive maritime and industrial activities. To investigate the penetration of heavy ... -
Concerning Sequential Spaces
( Qatar University , 1985 , Article)In this paper, important notions concerning sequential spaces are clarified new ideas, one of which is a complete and direct proof of the fundamental theorem characterizing sequential spaces, are introduced. -
Condition and trend of a depression-type habitat In rainfed desert rangelands of Qatar In response to fertilizer application
( Qatar University , 1994 , Article)Characteristics of a rainfed depression-type habitat in desert ranges, and its response to fertilizer application were studied. A single fertilizer application at a rate of 75 Kg ha1 prior to the rainy season improved range ... -
Conditionally Exponential Convex Functions On Locally Compact Groups
( Qatar University , 1993 , Article)The main objectives of this study are: 1) The construction of a compact base for the convex cone of all conditionally exponential convex functions. The determination of the extreme parts of this cone. -
Conductance Measurements in Corrosion Studies of Aluminium
( Qatar University , 1994 , Article)A new method is suggested for studying the rates of dissolution of oxide film on aluminium and its alloys. The method is based on measuring the conductance between two aluminium (or its alloys) electrodes immersed in 3.0 ... -
Congenital Anomalies in Down Syndrome Among Qatari Population
( Qatar University , 2006 , Article)Down Syndrome (DS) is the major cause of mental retardation and congenital heart disease affecting the welfare of over 300,000 individuals and their families in USA. The aim of the study is to see which are the most common ... -
Constituents of catha edulis (alkaloids, triterpenoids and related substances and saponins)
( Qatar University , 1989 , Article)The study of the alkaloids of khat samples from Egypt and Yemen revealed qualitative and quantitative differences. Cathine and the dimer of cathinone occured in both samples, while norephedine was detected only in Yemen ... -
Constituents Of Centaurea Species
( Qatar University , 1992 , Article)A comprehensive review of Centaurea species including all the isolated consituents is given. The biological activities of the studied species are also reported. -
Constituents Of Cymbopogon Species
( Qatar University , 1986 , Article)A comprehensive review of the Cymbopogon species including the essential oils and their constituents is given. An account of the other components viz. non volatile terpenoids and phenolic compounds is also given. The ... -
Constituents Of Green Beans Phaseolus Vulgaris (Lipids And Flavonoids)
( Qatar University , 1992 , Article)Chemical study of the lipid fraction resulted in the isolation and identification of a hydrocarbon fraction (n-Czg -0-033); an aliphatic alcohol fraction (C^, Czp, €30) and a sterol fraction (stigmasterol and sitosterol). ... -
Constituents of plants growing in qatar part xxvii: flavonoids Of cymbopogon parkeri
( Qatar University , 1995 , Article)The study of the flavonoids of Cymbopogon parkeri resulted the isolation and indentification of tricin and isoorientin. Three other flavonoids have been isolated and partially identified. -
Constituents of plants growing in qatar x.* seasonal variations of the volatile oil of cymbopogon parkeri
( Qatar University , 1985 , Article)The seasonal variation of the volatile oil of Cymbopogon parkeri Stapf. was studied. The oil content is higher during the hot dry season than during the humid hot season and the cold season. No qualitative differences among ... -
Constituents of plants growing in qatar xxiii. Flavonoids of francoeuria crispa
( Qatar University , 1993 , Article)Investigation of the flavonoid constituents of Francoeuria crispa, resulted in the isolation and identification of four flavonoids: quercetin, qucrcetin-3-O-gIucoside, quercetin-7-0-glucoside and quercetin-3-methyl ether. -
Constituents of plants growing in Qatar xxiv phytochemical investigation of salvia aegyptiaca L.
( Qatar University , 1994 , Article)The study of the flavonoids revealed the isolation and identification of luteolin, luteolin 7-O- glucoside, apigenin and apigenin 7-0 glucoside; their identity was proved by m.p., TLC, UV, IR and MS. Moreover, a coumarin ... -
Constituents of plants growing in qatar xxv flavonoids of Picris Radicata (forssk.) Less.
( Qatar University , 1994 , Article)Four flavonoids were isolated from the plant and were identified as apigenin, chrysin 7-glucoside, leuteoline and luteolin 7-glucoside. -
Constituents of plants growing in Qatar: part xxviii. Constituents Of cistanche phelypaea
( Qatar University , 1995 , Article)Ten compounds were isolated from the methanolic extract of the aerial parts of Cistanche phelypaea (Orobanchaceae) and identified as echinacoside (1), tubuloside A (2), tubuloside E (3), acteoside (4), 2'-acetylacteoside ... -
Contribution of the Fungal Flora and Mycotoxins of Some Canned Tomato Paste Samples
( Qatar University , 1994 , Article)Twenty-two species belonging to seven genera were isolated and identified from 21 tomato paste samples on glucose-Czapek's (5 genera and 14 species) and 10% NaCl-glucose-Czapek's (6 genera and 17 species) agar media, at ... -
Contribution To The Sedimentology Of The Bahariya Formation Of Gebel El-Dist, Bahariya Oasis, Western Desert, Egypt
( Qatar University , 1983 , Article)Combined microscopic, grain-size and heavy-mineral analyses were carried out on the Bahariya Formation at Gebel El-Dist (type section), Bahariya Oasis. These studies revealed that the formation is composed of moderately ... -
A convenient synthesis of Carbocyclic fused Thieno [2,3-b] Pyridines and Carbocyclic fused IH-Pyrazolo [3,4-b] Pyridines
( Qatar University , 2001 , Article)A synthesis of Carbocyclic fused thieno [2,3-b] pyridines and carbocyclic fused 1H- pyrazolo [3,4-b] pyridines utilizing car-bocyclic fused 2(lh)-pyridinethiones as starting components is described. The structures of the ...
