Browsing Qatar University Science Journal - [From 1981 TO 2007] by Title
Now showing items 124-143 of 770
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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 ... -
Copper Complexes Of Di-, Tri-, And Tetra-Peptides Containing Tryptophan, Histidine And Arginine
( Qatar University , 1983 , Article)Fifty Seven copper complexes of di-, tri-. and tetra-peptides containing tryptophan, histidine and arginine are studied spectrophotometrically. The ^a, and colour of the complexes are dependent on the sequence of the amino ... -
Coral Bleaching And Enso Anomaly : Was The Past Similar To The Present
( Qatar University , 1999 , Article)Bleaching of reef corals is due to partial or total loss of symbiotic micro-algae as a consequence of environmental stress such as an oceanic warming linked to the ocean-scale hydroclimatic anomaly termed ENSO (El Nino ... -
Coralline Algae from the Neoegne and Pleistocene Sequence of Mersa Alam, Red Sea, Egypt.
( Qatar University , 1982 , Article)Ten speciecs of family Corallinaceae (Coralline Algae) are herein recorded and described for the first time from the stratigraphic sequence of Mersa Alam, Red Sea, Egypt. Of these, Amphiroa knolli, Jania johnsoni and ... -
Correlations of partition data of carboxylic acids in water/organic solvent Systems with solvatochromic parameters
( Qatar University , 1994 , Article)The partition coefficients of C2-Cg carboxylic acid monomeric forms between water and various organic solvents as well as the dimerization constants have been shown to be well correlated in terms of the solvatochromic ... -
Corrosion of n-GaAs/aqueous Photoelectrochemical Cell
( Qatar University , 2005 , Article)A combination of electrochemical studies, scanning electron microscopy, SEM, and light reflectivity measurements reveals information about the corrosion of enlightened n-GaAs in various aqueous electrolytes. The corrosion ... -
A critical analysis of "harvest index"
( Qatar University , 1993 , Article)The many ways in which harvest index ratio (HI) can be used are discussed. A selection of published values for HI are given. Attention is drawn to the confusion in calculating the HI such that some present methods of ... -
Crystal hydration and vacancy enhanced isotopic exchange reactions in Heterogeneous solid - liquid systems
( Qatar University , 1994 , Article)The rate of some heterogeneous isotopic exchange reactions can be enhanced by the simultaneous hydration of the solid participating in the exchange process. The results presented here show that the concomitant hydration ... -
Cytological Studies On The Effect Of The Herbicide "Dual" On Allium Cepa
( Qatar University , 1988 , Article)Dual is widely used in Egypt as an active herbicide against annual grass weeds in soybean, sunflower, sugar beet and maize. Cytological studies have been carried out to show the effect of the herbicide on cell division in ... -
Cytology and palynology of common monocots in mariut, egypt i. Common species of the families alliceae and liliaceae
( Qatar University , 1994 , Article)The present sludy includes cytological and palynological investigations of five species belonging to the families Alliaceae and Liliaceae, as an impetus for more in-depth floristic, taxonomic and phytogeographical ...