Chemistry & Earth Sciences: Recent submissions
Now showing items 521-540 of 587
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Triterpenoids from Salvia aegyptiaca
(1993 , Article)Newly isolated secondary metabolites from Salvia aegyptiaca growing in Qatar -
Flavonoids from Centaurea sinaica
(1992 , Article)Four Newly isolated flavonoids from Centaurea sinaica -
(−)-Paniculatol, a new ent-labdane bromoditerpene from Laurencia paniculata
( Elsevier Science Ltd. , 1997 , Article)(−)-Paniculatol, 1, an unusual tricyclic bromoditerpene belonging to the ent-labdane series has been identified in the red alga Laurencia paniculata collected on Qatari coasts, Arabian Gulf. The structure displays an unusual ... -
Fatty acid composition of twelve algae from the Coastal Zones of Qatar
( Kluwer Academic Publishers , 1997 , Article)Fatty acid composition of twelve algal species from two different classes were determined. Three Chlorophyta species(Axetabularia calyxulux, Cladophors sericoides and Dictyosphaeria cavernosa) and nine Phaephyta species ... -
Phospholipid fatty acid composition of nine marine sponges from Qatar
( IFREMER , 1998 , Conference Paper)Phospholipid fatty acid composition was studied in sponge from Qatar including eight Demospongia and one Calcarea. More than 60 fatty acids were identified in each species as methyl esters and N-acyl pyrrolidides by gas ... -
Guaianolides from Picris radicata
( Elsevier Science Ltd. , 1996 , Article)The methylene chloride-methanol (1:1) extract of the aerial parts of Picris radicata Forssk afforded two new guaianolides. The structures were established from spectral data. -
Major sterol composition of some algae from Qatar
( Elsevier Science Ltd. , 1995 , Article)Thirteen macroscopic algae belonging to the three main divisions Chlorophyceae, Rhodophyceae and Phaeophyceae from the coast of Qatar (Arabian Gulf) were investigated for their sterol composition by using GC-MS coupling ... -
Charge-transfer complexes of 4-methylpiperidine with σ- and π-acceptors
( Elsevier B.V. , 2015 , Article)The solid charge-transfer (CT) molecular complexes formed in the reaction of the electron donor 4-methylpiperidine (4MP) with the σ-electron acceptor iodine and π-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), ... -
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. -
Loading Rates of Dust and Metals in Residential Houses of Arid and Dry Climatic Regions
( Taiwan Association for Aerosol Research , 2016 , Article)Dust samples were collected from 38 naturally ventilated houses for 12 weeks. Effects of three variables in two groups each were evaluated: proximity to traffic density (main- and side-roads), cigarettes smoking (smoking ... -
Mechanism and kinetics of electrochemical degradation of uric acid using conductive-diamond anodes
( Taylor & Francis , 2016 , Article)Uric acid (UA) is one of the principal effluents of urine wastewaters, widely used in agriculture as fertilizer, which is potentially dangerous and biorefractory. Hence, the degradation of UA (2,6,8-trihydroxy purine) in ... -
Aldehyde dehydrogenase expression in Metaphire posthuma as a bioindicator to monitor heavy metal pollution in soil
( BioMed Central , 2016 , Article)Background Soil contamination and associated pollution plays a detrimental role in soil flora and fauna. Soil is processed and remodeled by subterranean earthworms, accordingly are referred to as soil chemical engineers. ... -
Crystal structure of (E)-2-{[(6-methoxy-1,3-benzothiazol-2-yl)imino]methyl}phenol
( International Union of Crystallography , 2015 , Article)The title compound, C15H12N2O2S, crystallizes in the orthorhombic space group Pna21, with two molecules in the asymmetric unit (Z′ = 2). Each molecule consists of a 2-hydroxy Schiff base moiety linked through a spacer ... -
A Highly Selective Sensor for Cyanide in Organic Media and on Solid Surfaces
( MDPI AG , 2016 , Article)The application of IR 786 perchlorate (IR-786) as a selective optical sensor for cyanide anion in both organic solution (acetonitrile (MeCN), 100%) and solvent-free solid surfaces was demonstrated. In MeCN, IR-786 was ... -
Biomonitoring of Toxic Effects of Pesticides in Occupationally Exposed Individuals
( Elsevier , 2016 , Article)Background Workers in pesticide manufacturing industries are constantly exposed to pesticides. Genetic biomonitoring provides an early identification of potential cancer and genetic diseases in exposed populations. The ... -
Synthesis, immunomodulation and cytotoxic effects of vanadium (IV) complexes
( Bentham Science Publishers B.V. , 2014 , Article)Vanadium is known to exhibit several bioactivities and shows potential as a pharmaceutical drug. The current studies were conducted with the goal of synthesizing a new generation of oxovanadium(IV) complexes, investigating ... -
Mishandling and exposure of farm workers in Qatar to organophosphate pesticides
( Elsevier Inc. , 2014 , Article)We used a combination of subjective (questionnaire) and objective (urinary metabolites) measurements to evaluate factors that can predict the exposure of farm workers in Qatar to organophosphate pesticides and to assess ... -
Self-assembled zirconia nanotube arrays: Fabrication mechanism, energy consideration and optical activity
( Royal Society of Chemistry , 2014 , Article)We present a comprehensive roadmap for the precise control of the dimensions and optical properties of anodically fabricated zirconia nanotubes. The effects of anodization time, applied voltage, solvent composition, as ... -
Properties of a three-dimensionally ordered macro-mesoporous carbon-doped TiO2 composite catalyst
( World Scientific Publishing , 2013 , Article)This study aimed to develop an effective, environmentally benign composite catalyst composed of carbon materials and titanium dioxide (TiO2). Carbon-doped titanium dioxide (C-TiO2) was prepared by coating TiO2 onto ... -
Biophysical studies of the effect of high power ultrasound on the DNA solution
( Elsevier B.V. , 2014 , Article)Stability and molecular size of the DNA double helical structure were studied on an aqueous solution of DNA after exposure to high power doses of continuous wave ultrasound at frequency of 20kHz. Thermal transition ...
