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See detailChemical Composition of the Essential Oil of Pistacia lentiscus L. from Eastern Morocco
Amhamdi, Hassan; Aounti, Fatima; Wathelet, Jean-Paul ULg et al

in Record of Natural Products (2009), 3(2), 90-95

The essential oil from leaves of Pistacia lentiscus L., an aromatic member of the Anarcadiaceae family from Eastern Morocco, obtained by hydrodistillation, was analysed by GC-FID and GC-MS. The ... [more ▼]

The essential oil from leaves of Pistacia lentiscus L., an aromatic member of the Anarcadiaceae family from Eastern Morocco, obtained by hydrodistillation, was analysed by GC-FID and GC-MS. The constituents were identified by their mass spectra and Kovats’indices. About 104 constituents were detected in the oil. From these components, about 40 could be identified and quantified, comprising over 88.6% of the oil. The main constituents of the oil were: myrcene (39.2%), limonene (10,3) -gurjunene (7.8), germacrene (4.3%), -pinene (2.9%), muurolene (2.9), -humulene (2.6), Epi- bicyclosesquiphellandrene (2.5), -pinene (2.2). The results of this study shows both qualitative and quantitative differences with oils from P. lentiscus L of other countries. [less ▲]

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See detailThe chemical composition of the extreme halo stars. I - Blue spectra of 20 dwarfs
Magain, Pierre ULg

in Astronomy and Astrophysics (1989), 209

Spectra obtained with the ESO Cassegrain echelle spectrograph are used to determine the abundances of 13 elements in the atmospheres of 20 extreme halo dwarfs. It is found that the alpha elements Mg, Ca ... [more ▼]

Spectra obtained with the ESO Cassegrain echelle spectrograph are used to determine the abundances of 13 elements in the atmospheres of 20 extreme halo dwarfs. It is found that the alpha elements Mg, Ca, and Ti are overabundant with respect to Fe, that the Cr/Fe ratio is solar at all metallicities, and that Al is overdeficient relative to Mg. The results also indicate that the s elements Sr, Y, and Ba are overdeficient with respect to Fe in stars with Fe/H ratios of less than 2.3, and that for ratios greater than 2.3 the s element abundances relative to Fe are roughly constant (at either solar or higher values). [less ▲]

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See detailThe chemical composition of the extreme halo stars. II - Green spectra of 20 dwarfs
Zhao, G.; Magain, Pierre ULg

in Astronomy and Astrophysics (1990), 238

The abundances of nine elements in the atmospheres of 20 extreme metal-poor stars are derived from green spectra obtained with the ESO Cassegrain Echelle Spectrograph (CASPEC). Sodium is found to be ... [more ▼]

The abundances of nine elements in the atmospheres of 20 extreme metal-poor stars are derived from green spectra obtained with the ESO Cassegrain Echelle Spectrograph (CASPEC). Sodium is found to be overabundant with respect to aluminum by as much as one dex. There is some scatter in Ca/Fe which cannot be accounted for by random errors in equivalent widths or atmospheric parameters. Scandium is overabundant relative to iron. Some barium lines may be affected by strong departures from local thermodynamic equilibrium. The nitrogen-rich metal-poor star HD 74000, which was found in previous work to be also Al-rich, also presents higher than usual abundances of Na and of s-process elements. It can thus be considered as a mild barium dwarf of Population II. [less ▲]

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See detailThe chemical composition of the extreme halo stars. III - Equivalent widths of 20 dwarfs
Zhao, G.; Magain, Pierre ULg

in Astronomy and Astrophysics. Supplement Series (1990), 86

In the first two papers of this series the chemical composition of 20 extreme halo stars was discussed. The abundances of a number of elements were determined using model atmosphere analysis of equivalent ... [more ▼]

In the first two papers of this series the chemical composition of 20 extreme halo stars was discussed. The abundances of a number of elements were determined using model atmosphere analysis of equivalent widths. In this paper a tabulation of the equivalent width data is presented. A comparison of the measurements with the equivalent widths from different sources is used to assess the quality of the data. [less ▲]

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See detailChemical Composition Of The Leaf Oil Of Mentha Rotundifolia (L.) From Algeria
Brada, M.; Bezzina, M.; Marlier, M. et al

in Journal of Essential Oil Research (2006), 18(6), 663-665

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See detailChemical Composition of Volatile Oils from Algerian Nigella sativa L. seeds
Benkaci-Ali, Farid; Baaliouamer, Aoumeur; Wathelet, Jean-Paul ULg et al

in Journal of Essential Oil Research (2009)

The chemical composition of the volatiles obtained from the fixed oils of Nigella sativa L. seeds, growing in Algeria, was investigated by GC and GC/MS analysis. Two solvents were studied for extracting ... [more ▼]

The chemical composition of the volatiles obtained from the fixed oils of Nigella sativa L. seeds, growing in Algeria, was investigated by GC and GC/MS analysis. Two solvents were studied for extracting the oils, hexane and isopropanol. The composition of Nigella sativa seeds varieties having four location origins in Algeria, were determined. Alcohols and ketones formed the main proportion using the two solvents, respectively (hexane: 27.4-36.1 %, isopropanol: 40.2-59.0 %) and (hexane: 39.9-44.3 %, isopropanol: 17.5-50.7 %), among which thymoquinone and thymohydroquinone were the predominant antioxidant compounds. The monoterpene hydrocarbons constitute relatively the lower fraction compared to the precedent chemical families, particularly by using the isopropanol solvent. [less ▲]

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See detailChemical Composition, Cytotoxic and Antioxydant Activity of The Essential Oil of Lavandula dentata
Imelouane, B.; El Bachiri, A.; Wathelet, Jean-Paul ULg et al

in World Journal of Chemistry (2010), 5(2), 103-110

The composiiton of the essential oil from aerial part and flowers of lavandula dentate, collected in eastern Morocco (Taforalt, Talazart), were analysed by GC/FID and GC-MS.

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See detailChemical composition, cytotoxicity and in vitro antitrypanosomal and antiplasmodial activity of the essential oils of four Cymbopogon species from Benin.
Kpoviessi, Salome; Bero, Joanne; Agbani, Pierre et al

in Journal of ethnopharmacology (2014), 151

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon species are largely used in folk medicine for the treatment of many diseases some of which related to parasitical diseases as fevers and headaches. As part of ... [more ▼]

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon species are largely used in folk medicine for the treatment of many diseases some of which related to parasitical diseases as fevers and headaches. As part of our research on antiparasitic essential oils from Beninese plants, we decided to evaluate the in vitro antiplasmodial and antitrypanosomal activities of essential oils of four Cymbopogon species used in traditional medicine as well as their cytotoxicity. MATERIALS AND METHODS: The essential oils of four Cymbopogon species Cymbopogon citratus (I), Cymbopogon giganteus (II), Cymbopogon nardus (III) and Cymbopogon schoenantus (IV) from Benin obtained by hydrodistillation were analysed by GC/MS and GC/FID and were tested in vitro against Trypanosoma brucei brucei and Plasmodium falciparum respectively for antitrypanosomal and antiplasmodial activities. Cytotoxicity was evaluated in vitro against Chinese Hamster Ovary (CHO) cells and the human non cancer fibroblast cell line (WI38) through MTT assay to evaluate the selectivity. RESULTS: All tested oils showed a strong antitrypanosomal activity with a good selectivity. Sample II was the most active against Trypanosoma brucei brucei and could be considered as a good candidate. It was less active against Plasmodium falciparum. Samples II, III and IV had low or no cytotoxicity, but the essential oil of Cymbopogon citraus (I), was toxic against CHO cells and moderately toxic against WI38 cells and needs further toxicological studies. Sample I (29 compounds) was characterised by the presence as main constituents of geranial, neral, beta-pinene and cis-geraniol; sample II (53 compounds) by the presence of trans-p-mentha-1(7),8-dien-2-ol, trans-carveol, trans-p-mentha-2,8-dienol, cis-p-mentha-2,8-dienol, cis-p-mentha-1(7),8-dien-2-ol, limonene, cis-carveol and cis-carvone; sample III (28 compounds) by beta-citronellal, nerol, beta-citronellol, elemol and limonene and sample IV (41 compounds) by piperitone, (+)-2-carene, limonene, elemol and beta-eudesmol. CONCLUSIONS: Our study shows that essential oils of Cymbopogon genus can be a good source of antitrypanosomal agents. This is the first report on the activity of these essential oils against Trypanosoma brucei brucei, Plasmodium falciparum and analysis of their cytotoxicity. [less ▲]

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See detailChemical Composition, Insecticidal Effect and Repellent Activity of Essential Oils of Three Aromatic Plants, Alone and in Combination, towards Sitophilus Oryzae L. (Coleoptera : Curculionidae)
Ngassoum, Martin B.; Ngamo Tinkeu, Léonard S.; Ngatanko, Iliassa et al

in Natural Product Communications [=NPC] (2007), 2(12), 1229-1232

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See detailChemical composition, microstructure and physical properties of magnetically melt-textured bulk Bi2Sr2Ca0.8Dy0.2Cu2O8-y superconducting ceramics
Stassen, Sophie; Cloots, Rudi ULg; Vanderschueren, André et al

in Balachandran, U.; McGinn, P. J.; Abell, J. S. (Eds.) High Temperature Superconductors: Synthesis, Processing, and Large-Scale Applications. (1996)

Dysprosium doped Bi-based 2212 ceramics were synthesized by a melt-texturing growth process in a 1.2 T magnetic field, applied perpendicularly to the main axis of a cylindrical shape sample. Four well ... [more ▼]

Dysprosium doped Bi-based 2212 ceramics were synthesized by a melt-texturing growth process in a 1.2 T magnetic field, applied perpendicularly to the main axis of a cylindrical shape sample. Four well oriented and chemically defined phases forming successive layers were observed and characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The origin and composition of such layers is described. A novel aspect is the calcium solubility at the strontium site in 2212 phases, and the strontium solubility at the calcium site in 8250 structures. The texturing process was optimized with respect to the sample electrical resistivity and ac magnetic susceptibility. The critical current density was then evaluated. [less ▲]

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See detailThe Chemical compositions and the Antioxidant and Antimicrobial Activities of the Essential Oil of Rosemary Leaves from Eastern Morocco
Tahri, Mustapha; Imelouane, Bouchra; Amhamdi, Hassan et al

in Journal of Materials and Environmental Science (2015), 6(3), 666-672

The essential oils compositions of Rosmarinus. tournefortii wild plant, Rosmarinus. tournefortii domesticated plant, and Rosmarinus officinalis.L wild plant growing in different bio climates from eastern ... [more ▼]

The essential oils compositions of Rosmarinus. tournefortii wild plant, Rosmarinus. tournefortii domesticated plant, and Rosmarinus officinalis.L wild plant growing in different bio climates from eastern Morocco, was determined by GC-FID and GC–MS. Oils were assessed for their antimicrobial and antioxidant activities. A variation of chemical compositions attributed to varieties rather than to bio climates was revealed. α-Pinene (0.637% ; 44.22% ; 5.74%), Camphene (11.62% ; 6.52% ; 2.21%), ß-Pinene (14.72% ; 1.14% ; 3.71%), 1,8-Cineole (10.1% ; not identifying ; 56.51%) and Camphor (39.27% ; 7.64% ; 13.56%) were identified as the main constituents of R. tournefortii wild plant, R. tournefortii domesticated plant, and R. officinalis. L wild plant respectively. This study is based on the determination of the diameter of inhibition to moderate antimicrobial and antioxidant activities of oils revealed to be against eight bacteria tested. This was determined by 1,1-diphenyl-1-picrylhydrazyl (DPPH) assay. The highest antimicrobial and antioxidant activities were found in oils from Rosmarinus. tournefortii domesticated plant. [less ▲]

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See detailChemical contamination along the Mediterranean French coast using Posidonia oceanica (L.) Delile above-ground tissues: a multiple trace element study
Luy, Nicolas; Gobert, Sylvie ULg; Sartoretto, Stéphane et al

in Ecological Indicators (2012), 18

Levels of Be, Al, V, Mn, Co, As, Se, Mo, Ag, Sn, Sb, Bi as well as of Cr, Fe, Ni, Cu, Zn, Cd and Pb in Posidonia oceanica (L.) Delile from the Mediterranean French coast were analysed using DRC ICP-MS ... [more ▼]

Levels of Be, Al, V, Mn, Co, As, Se, Mo, Ag, Sn, Sb, Bi as well as of Cr, Fe, Ni, Cu, Zn, Cd and Pb in Posidonia oceanica (L.) Delile from the Mediterranean French coast were analysed using DRC ICP-MS. The first twelve elements have not been well studied and can be considered to be potential pollutants as a result of potentially increased levels resulting from anthropogenic activities. Spatial variation and/or compartmentalization were found for all trace elements. Except for Al, Cr, Fe, Cu and Ag, most trace elements were preferentially accumulated in photosynthetic tissues, suggesting uptake from the water column. Moreover, for Be, V, Mn, Co, Ni, As, Mo, Sb, Sn and Pb, adult leaves had higher levels than intermediate leaves, suggesting low kinetics of accumulation. Levels in the third intermediate leaf were representative of the average levels of the integral shoot, and thus can be used alone in chemical biomonitoring. For most of the twelve little-studied trace elements, the background levels of the northwestern Mediterranean Sea can be measured, and their spatial variation can be related to anthropogenic activities. Levels of the seven widely studied trace elements seem to decrease or stabilize over time, probably due to their reduced anthropogenic use. These observations show that P. oceanica is a sensitive bioindicator for the monitoring of chemical contamination of a large number of trace elements. [less ▲]

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See detailChemical contamination in fish species from rivers in the North of Luxembourg: Potential impact on the Eurasian otter (Lutra lutra).
Boscher, Aurore; Gobert, Sylvie ULg; Guignard, C. et al

in Chemosphere (2010), 78

Contamination levels of PCBs, and of the heavy metals cadmium (Cd), lead (Pb) and mercury (Hg) were analyzed in four fish species from seven rivers in the North of Luxembourg. During August and September ... [more ▼]

Contamination levels of PCBs, and of the heavy metals cadmium (Cd), lead (Pb) and mercury (Hg) were analyzed in four fish species from seven rivers in the North of Luxembourg. During August and September 2007, 85 samples of fish were collected belonging to four species: the stone loach (Barbatula barbatula, n = 12 pools), the chub (Squalius cephalus, n = 36), the barbel (Barbus barbus, n = 23) and eel (Anguilla anguilla, n = 14). The concentration of seven indicator PCBs (P7PCBs) reached a mean of 39 ng g􏰀1 and varied between 4.0 and 346.2 ng g􏰀1 (wet wt) depending on the site and species. Fish collected at Wal- lendorf on the Our River and sites on the Wiltz and the Clerve rivers showed the highest concentrations for PCBs. In comparison with 1994, PCB levels in fish decreased strongly during the last decade in these rivers. Lead was detected at low levels (0–181.4 ng g􏰀1 wet wt). Mercury concentrations ranged between 10.3 and 534.5ngg􏰀1 (wet wt) exceeding maximum tolerable levels for human consumption of 500 ng g􏰀1 in two fish out of 85. Chubs and eels from the Sûre River were the most contaminated by mer- cury. Cadmium levels varied between 4.0 and 103.9 ng g􏰀1 (wet wt). In addition to mercury in fish, cad- mium was the most problematic pollutant on the Our, the Wiltz, the Clerve and the Troine Rivers, because values found in 20% of fish exceeded the threshold of about 10–50 ng g􏰀1 (wet wt) recommended for human health. The total PCB level predicted to accumulate in livers from otter potentially feeding on these fish based on a previously published mathematical model is 37.7 lg g􏰀1 (lipid wt), which is between a proposed ‘‘safe level” and a ‘‘critical level” for otters. Rivers in the North of Luxembourg are thus to some extent polluted, and the establishment of otter populations could be affected by current levels of contamination. [less ▲]

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See detailChemical control of Haplodiplosis marginata (Diptera: Cecidomyiidae)
Censier, Florence ULg; Chavalle, Sandrine; Wittouck, Daniël et al

Poster (2012, May)

The saddle gall midge, Haplodiplosis marginata (von Roser), is a European pest of cereals. The larvae overwinter into the soil. Emergence of adult midges occurred during the spring and after mating ... [more ▼]

The saddle gall midge, Haplodiplosis marginata (von Roser), is a European pest of cereals. The larvae overwinter into the soil. Emergence of adult midges occurred during the spring and after mating, females lay their eggs on the leaves of cereals and several grasses. Eggs hatch a few days later; young larvae crawl to the stem and introduce themselves between the leaf sheath and the stem, were the larvae develop. As reaction of the presence of midge larvae, stem produce a longitudinal depression of 6-7 mm ended by two ridges looking as a horse saddle. When galls are numerous, they can cause break of stems and important yield losses. The saddle gall midge, which is a major pest in Central Europe, is not very well known in the Western part of the continent. It had already caused huge damage during outbreak periods. The last one reported in Belgium and in The Netherlands occurred between 1965 and 1970. Later, it was never reported again until 2010, where large populations and severe damage were observed, especially in the Flemish polders, a region with clay soils where wheat is cropped intensively. Faced with the resurgence of this pest, we sought to develop effective curative control. To date, crops chemical protection seems to be the only solution in case of heavy emergences. Experimentation was conducted in a highly infested field (Meetkerke, Belgian Polders), according to a randomized complete block arrangement with four replications. Foremost, a lambdacyhalothrin-based insecticide was used to evaluate efficiency of several protection schemes, ranging between one and four spray(s). The large spread of flights observed during the 2011 spring allowed to highlight the effect of treatment date on the attack intensity and also on the galls distribution along the stem, on the different internodes. Moreover, several insecticides already registrated in cereals against aphids were compared for their efficacy against saddle gall midge. Studied pyrethroids have shown a very good efficacy, ranging between 75 % and 87 %, when applied twice with a 2 weeks interval. To be efficient, chemical spray must be synchronized with the flights and egg laying periods. Monitoring the phenology of flights is thus essential as part of integrated pest management against saddle gall midge. [less ▲]

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See detailChemical control of Haplodiplosis marginata (Diptera: Cecidomyiidae)
Censier, Florence ULg; Chavalle, Sandrine; Wittouck, Daniël et al

in Communications in Agricultural and Applied Biological Sciences (2012), 77(4), 667-675

The saddle gall midge, Haplodiplosis marginata (von Roser), has been detected in Belgium since 2010, after several decades without any reporting. It had indeed caused serious damages between 1965 and 1970 ... [more ▼]

The saddle gall midge, Haplodiplosis marginata (von Roser), has been detected in Belgium since 2010, after several decades without any reporting. It had indeed caused serious damages between 1965 and 1970. This insect is a European cereal pest whose larvae feed on stems and engender saddle-shaped depressions, resulting in yield losses. Face with the resurgence of this pest, it was decided to study its spatial distribution and, because serious damages were observed in some regions, to develop effective curative control. To date, chemical protection seems to be the only immediate solution in case of heavy emergences. Experimentation was conducted in a highly infested field (Meetkerke, Belgian Polders), according to a randomized complete blocks arrangement with four replications. Foremost, a lambdacyhalothrin-based insecticide was used to evaluate efficiency of several protection schemes, ranging between one and four spray(s). The large spread of flights observed during the 2011 spring allowed to highlight the effect of treatment date on the attack intensity and also on the galls distribution along the stem, on the different internodes: the lower internodes were protected by the early sprayings, while last sprayings induced reduction of galls number on the upper internodes. Moreover, several insecticides already registrated in cereals against aphids were compared for their efficacy against saddle gall midge. Studied pyrethroids have shown a very good efficacy, ranging between 75 % and 87 %, when applied twice with a 2 weeks interval. To be efficient, insecticide applications must thus be synchronized with the flights and egg-laying periods. Monitoring the phenology of flights is thus essential as part of integrated pest management against saddle gall midge. [less ▲]

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See detailChemical control of Haplodiplosis marginata von Roser (Diptera : Cecidomyiidae)
Censier, Florence ULg; Chavalle, Sandrine; Wittouck, Daniel et al

in Communications in Agricultural and Applied Biological Sciences (2012), 78(4), 667-675

The saddle gall midge, Haplodiplosis marginata (von Roser), has been detected in Belgium since 2010, after several decades without any reporting. It had indeed caused serious damages between 1965 and 1970 ... [more ▼]

The saddle gall midge, Haplodiplosis marginata (von Roser), has been detected in Belgium since 2010, after several decades without any reporting. It had indeed caused serious damages between 1965 and 1970. This insect is a European cereal pest whose larvae feed on stems and engender saddle-shaped depressions, resulting in yield losses. Face with the resurgence of this pest, it was decided to study its spatial distribution and, because serious damages were observed in some regions, to develop effective curative control. To date, chemical protection seems to be the only immediate solution in case of heavy emergences. Experimentation was conducted in a highly infested field (Meetkerke, Belgian Polders), according to a randomized complete blocks arrangement with four replications. Foremost, a lambdacyhalothrin-based insecticide was used to evaluate efficiency of several protection schemes, ranging between one and four spray(s). The large spread of flights observed during the 2011 spring allowed to highlight the effect of treatment date on the attack intensity and also on the galls distribution along the stem, on the different internodes: the lower internodes were protected by the early sprayings, while last sprayings induced reduction of galls number on the upper internodes. Moreover, several insecticides already registrated in cereals against aphids were compared for their efficacy against saddle gall midge. Studied pyrethroids have shown a very good efficacy, ranging between 75 % and 87 %, when applied twice with a 2 weeks interval. To be efficient, insecticide applications must thus be synchronized with the flights and egg-laying periods. Monitoring the phenology of flights is thus essential as part of integrated pest management against saddle gall midge. [less ▲]

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See detailChemical ecology in forensic entomology
Dekeirsschieter, Jessica ULg; Frederickx, Christine ULg; Verheggen, François ULg et al

Scientific conference (2010, January 07)

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See detailChemical ecology of Aphids
Boullis, Antoine ULg; Francis, Frédéric ULg; Verheggen, François ULg

in VILCINSKAS, Andreas (Ed.) Biology and Ecology of Aphids (2015)

Aphids are widespread insects considered as crop pest throughout the world. In order to control them, different techniques are known. The study of aphid-related semiochemicals is one topic recently ... [more ▼]

Aphids are widespread insects considered as crop pest throughout the world. In order to control them, different techniques are known. The study of aphid-related semiochemicals is one topic recently studied in integrated pest management, used to control aphid outbreaks. These semiochemicals include those involved in intraspecific communication, in communication among different trophic levels, those which attract or repel aphids, or those which enhance the efficiency of aphid natural enemies. This book chapter summarises the recent findings on aphid chemical ecology, from the discovery of molecules of interest, to their use in IPM methods. [less ▲]

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