References of "Eppe, Gauthier"
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See detailValidated ready-to-use GC-MS/MS method for dioxin analysis in food and feed following the new EU Regulations
L'Homme, Benjamin ULg; Sandy, Chris; Scholl, Georges ULg et al

in Organohalogen Compounds (in press)

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See detailDocument Kinetic study of volatile oil of Curcuma longa L. rhizome and Carum carvi L. fruits extracted by microwave-assisted techniques using the cryogrinding
Akloul, R; Benkaci-Ali, F; Eppe, Gauthier ULg

in Journal of Essential Oil Research (in press)

Hydrodistillation assisted by microwave (HDAM) and steam distillation assisted by microwave (SDAM) of Curcuma longa L. rhizome (CL) and Carum carvi fruits (CC) were investigated. The effect of the ... [more ▼]

Hydrodistillation assisted by microwave (HDAM) and steam distillation assisted by microwave (SDAM) of Curcuma longa L. rhizome (CL) and Carum carvi fruits (CC) were investigated. The effect of the cryogrinding (CG) showed differences in yields and composition of volatile oils compared with classical grinding. HDAM–CG (CL: 1.20%, CC: 1.25%) and SDAM–CG (CL: 1.45%, CC: 1.75%) allowed extraction of substantial amounts of volatile oils in less time compared with HDAM (CL: 0.6%, CC: 1.00%) and SDAM (CL: 0.90%, CC: 1.00%). In addition, the major amounts of volatile oils were globally obtained during the first 5 and 10 minutes of extraction for CL and CC, respectively. A kinetic study of essential oils extraction from CL and CC was quantitatively performed. The composition of the major components and family classes present a significant variation with the extraction time. Essential oils extracted by these two methods were quantitatively (yield) and qualitatively [aromatic profile by gas chromatography (GC) and GC–mass spectrometry (GC–MS)] analyzed. There were differences, especially in the major compounds ar-turmerone (HDAM: 46.00–57.96%, HDAM–CG: 30.85–60.32%) and β-turmerone (HDAM: 14.43–16.74%, HDAM–CG: 10.46–15.77%) for CL, and limonene (HDAM: 23.61–56.97%, HDAM–CG: 38.04–43.00%) and carvone (HDAM: 36.19–64.54%, CC–CG: 53.65–56.31%) for CC. [less ▲]

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See detailDietary early-life exposure to contaminated eels does not impair spatial cognitive performances in adult offspring mice as assessed in the Y-maze and the Morris water maze
Dridi, ImenI; Leroy, Delphine; Guignard, Cedric et al

in Nutrition Research (in press)

Many environmental contaminants are introduced via the diet and may act as neurotoxins and endocrine disrupters, especially influencing growing organisms in early life. The purpose of this study was to ... [more ▼]

Many environmental contaminants are introduced via the diet and may act as neurotoxins and endocrine disrupters, especially influencing growing organisms in early life. The purpose of this study was to examine whether dietary exposure of dams to fish naturally contaminated with xenobiotics, especially with polychlorinated biphenyls (PCBs) and heavy metals (e.g. mercury and lead), resulted in cognitive function deficits in adult offspring mice. Daily, four groups of dams (n = 10/group) ingested standard diet plus paste with/without eels, during gestation and lactation, from gestational day (GD) six until post natal day (PND) 21 (weaning). Dams orally ingested a standardized amount of eel (0.8 mgkg-1 d-1) containing the six non-dioxin-like (NDL) PCBs (σ6 NDL-PCBs: 28, 52, 101, 138, 153, and 180) at 0, 85, 216, and 400 ngkg-1 d-1. Results showed that early-life exposure to contaminated eels did not (compared to non-exposed controls) impair immediate working memory in the Y-maze in the offspring assessed at PND 38. Furthermore, it did not significantly impact spatial learning and retention memory as measured in the Morris water maze in adult offspring mice (PND 120-123). Our results suggest that perinatal exposure to contaminated eels does not affect spatial cognitive performances, as assessed by the Y-maze and Morris water maze at adult age. Adverse effects of xenobiotics reported earlier might be camouflaged by beneficial eel constituents, such as n-3 fatty acids. However, additional studies are needed to differentiate between potential positive and negative effects following consumption of food items both rich in nutrients and contaminants. © 2014 Elsevier Inc. [less ▲]

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See detailWhen microplastic is not microplastic: ingestion of artificial cellulose fibers by macrofauna living in seagrass macrophytodetritus
Collard, France ULg; Remy, François ULg; Gilbert, Bernard ULg et al

Poster (2014, December 12)

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station ... [more ▼]

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station. Contents of digestive tracts were analyzed and fibers of various sizes and colors were found. Fibers were found in 27.6% of the digestive tracts in the nine dominant species. No correlation was found between number of fibers and taxonomic or trophic level. There were no seasonal or spatial preferences and thus we hypothesize that the organisms ingest these fibers randomly throughout the year. Analyses performed with a Raman spectroscope showed that these fibers were composed of cellulose associated with a coloring agent following the fiber color. Red fibers were dyed with the Direct Red 28, blue fibers were dyed with Direct Blue 22. Analyses by a scanning electron microscope (SEM) showed that cellulose fibers had the particular morphology of artificial cellulose fibers called: viscose. Our SEM analyses were compared to literature. This comparison assessed that fibers found in digestive tracts were made of viscose. In a first approach, viscose fibers looked like microplastic fibers because of their color and shape. However, it appeared that these fibers were made of artificial cellulose which is very different than plastic in terms of impacts and fate in the organisms. This study highlights the importance of physico-chemical analyses such as Raman spectroscopy and SEM to certainly identify the composition of particles ingested by organisms. From an ecological point of view, the red coloring agent is known to be carcinogenic in mammals and fish. Consequently, this pollution could provoke an environmental problem for the P. oceanica litter vagile macrofauna. [less ▲]

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See detailThe use of Ion Mobility Mass Spectrometry for isomer composition determination extracted from Se-rich yeast
Far, Johann ULg; Delvaux, Cédric ULg; Kune, Christopher ULg et al

in Analytical Chemistry (2014), just accepted

The isomer ratio determination of a selenium-containing metabolite produced by Se-rich yeast was performed. Electrospray Ionization and Ion Mobility Mass Spectrometry (IM-MS) were unsuccessfully used in ... [more ▼]

The isomer ratio determination of a selenium-containing metabolite produced by Se-rich yeast was performed. Electrospray Ionization and Ion Mobility Mass Spectrometry (IM-MS) were unsuccessfully used in order to resolve the isomers according to their Collisional Cross Section (CCS) difference. The isomer ratio determination of 2,3-dihydroxypropionylselenocystathionine was performed after multidimensional liquid chromatography preconcentration from a water extract of Se-rich yeast using preparative size exclusion, anion exchange and capillary reverse phase columns coupled to IM-MS. 4’-nitrobenzo-15-crown-5 ether, a Selective Shift Reagent (SSR), was added after the last chromatographic dimension in order to specifically increase the CCS of one of the isomers by the formation of a stable host-guest system with the crown-ether . Both isomers were consequently fully resolved by IM-MS and the relative ratio of the isomers was determined: 11-13% and 87-89%. The present data compared favorably with literature to support the analytical strategy despite the lack of authentic standard for method validation. In addition, computational chemistry methods were successfully applied to design the SSR and to support the experimental data. [less ▲]

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See detailMeasurement uncertainty for persistent organic pollutants by isotope dilution mass spectrometry
Eppe, Gauthier ULg; Diletti, G; Fernandes, A et al

in Organohalogen Compounds (2014, September), 76

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See detailContribution of ion mobility for structural analysis and analytical chemistry: Use of selective IMS shift reagents (SSR)
Kune, Christopher ULg; Far, Johann ULg; Delvaux, Cédric ULg et al

Poster (2014, June 19)

Ion mobility is a gas phase separation technique based on the Collisional Cross Section (CCS) of ions. It discriminates isobaric and isomeric ions provided their CCS difference is larger than the ... [more ▼]

Ion mobility is a gas phase separation technique based on the Collisional Cross Section (CCS) of ions. It discriminates isobaric and isomeric ions provided their CCS difference is larger than the instrumental resolution. This work proposes a new method to overcome this limitation while providing additional structural information. A Selective Shift Reagent (SSR) is a ligand specifically modifying the CCS of ions. Indeed specific non-covalent complexes can be form with a suitable SSR to reach the required selectivity and the CCS induced shift. A CID dissociation of the complex may be used after IMS separation to produce specific MS/MS spectra of the targeted analyte. This concept paves the way for new analytical strategies by ion mobility based on non-covalent complex formation. [less ▲]

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See detailInnovative analytical strategies for small molecules analysis by ion-mobility mass spectrometry
Eppe, Gauthier ULg; Goscinny, Séverine; Far, Johann ULg et al

Conference (2014, January)

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See detailComposition and biological activities of the essential oil of Nigella sativa seeds isolated by accelerated microwave steam distillation with cryogenic grinding
Alkoul, R; Benkaci-Ali, F; Zerrouki, M et al

in American Journal of Essential Oils and Natural Products (2014), 1(3), 23-33

In this study, essential oil of Sahara Nigella sativa L. was extracted using a rapid extraction, the microwave steam distillation (MSD) and the cryogenic grinding (CG). Two procedures have been ... [more ▼]

In this study, essential oil of Sahara Nigella sativa L. was extracted using a rapid extraction, the microwave steam distillation (MSD) and the cryogenic grinding (CG). Two procedures have been investigated, the MSD1 (seeds inside of oven apparatus) and MSD2 (seeds outside of oven apparatus). Forty-six compounds were identified and significant differences in quantities of the major constituents were observed, mainly were thymoquinone (CLG: 331.82-443.55 mg and CG: 272.95- 413.57 mg/100 g of seeds), p-cymene (CLG: 181.71-244.17 mg, CG: 369.80- 374.40 mg/100 g of seeds), dehydro-sabina ketone (CLG: 24.60- 25.83 mg, GC: 44.02-50.69 mg/100g of seeds), carvacrol (CLG: 10.32-10.96 mg, CG: 3.91-12.67 mg/100 g of seeds) and longifolene (CLG: 11.90- 16.43 mg, CG: 12.72-19.58 mg/100 g of seeds).Results showed that essential oils exhibit a good activity in each antioxidant system with a special attention for β-carotene bleaching test (IC50: 21 to 27 μg/ml) and reducing power (EC50: 9 to 14 μg/ml).The N. Sativa essential oils exhibited higher antibacterial and antifungal activities varying according to technique extraction and grinding mode used, with a high effectiveness against Gram-positive bacteria with a diameter of inhibition zones growth ranging from 9.5 to 35 mm and MIC and MBC values ranging from (0.042–0.10 mg/ml) to (0.20–0.75 mg/ml), respectively [less ▲]

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See detailMatrix ‐ assisted laser desorption/ionization mass spectrometry and Raman spectroscopy: An interesting complementary approach for lipid detection in biological tissues
Jadoul, Laure ULg; Malherbe, Cédric ULg; calligaris, David et al

in European Journal of Lipid Science and Technology [=EJLST] (2014)

Recently, matrix‐assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) has emerged as a powerful technique to study the distribution of lipids. However, quantification still remains a ... [more ▼]

Recently, matrix‐assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) has emerged as a powerful technique to study the distribution of lipids. However, quantification still remains a challenge because the MALDI signal is strongly affected by ion suppression effects. On the contrary, Raman spectroscopy is recognized as a non‐destructive analysis method and spectral images can also be acquired. The combination of these two techniques was applied for lipids detection in tissue sections. In MALDI, two lipids families (glycerophosphocholine, PC; gycerophosphoethanolamine, PE), three MALDI matrices (1,5‐diaminonapthalene, 1,5‐DAN; 2,5‐dihydroxybenzoic acid, 2,5‐DHB; a‐4‐hydroxicinammic acid, CHCA), and various mixtures of lipids were investigated. The nature of the lipid, as well as the nature of the matrix and the composition of the sample influences the signal of a given lipid. In Raman, despite a strong overlap with the spectrum of the native tissue, an intensity profile constructed along the diameter of the section clearly shows that the signature of one given lipid (a glycerophosphocholine) can be detected on a doped biological sample. [less ▲]

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See detailDetermination of the Al2O3 content in NaF-AlF 3-CaF2-Al2O3 melts at 950 °c by raman spectroscopy
Malherbe, Cédric ULg; Eppe, Gauthier ULg; Gilbert, Bernard ULg

in Analytical Chemistry (2014)

Thein situ control of the chemical composition of industrial aluminum smelter is a challenge mainly for physicochemical reasons: high temperature, high surrounding electromagnetic field, and the highly ... [more ▼]

Thein situ control of the chemical composition of industrial aluminum smelter is a challenge mainly for physicochemical reasons: high temperature, high surrounding electromagnetic field, and the highly corrosive molten salt electrolyte to deal with. In previous works, we proposed that Raman spectroscopy is a method of choice that could be adapted to real smelters. The laboratory study presented here relies on reproducible Raman spectra recorded on molten mixtures whose compositions are identical to those used during the production of aluminum. A normalization procedure for the Raman spectra is proposed based on the equilibria taking place in the bath. In addition, we discuss two quantitative models to determine the alumina content from the Raman spectra of the molten NaF−AlF3−CaF2−Al2O3 electrolytes. Univariate and multivariate approaches are applied to determine both theCOx (alumina content) and the CR (NaF/AlF3 molar ratio) by Raman spectroscopy without referring to an additional internal reference of intensity. The procedure was successfully tested and validated on industrial samples. [less ▲]

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See detailLack of isocitrate lyase in Chlamydomonas leads to changes in carbon metabolism and in the response to oxidative stress under mixotrophic growth.
Plancke, Charlotte; Vigeolas, Hélène ULg; Hohner, Ricarda et al

in The Plant journal : for cell and molecular biology (2014), 77(3), 404-417

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the ... [more ▼]

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the tricarboxylic acid (TCA) cycle in which CO2 is evolved. In this paper, a null icl mutant of the green microalga Chlamydomonas reinhardtii is described. Our data show that isocitrate lyase is required for growth in darkness on acetate (heterotrophic conditions), as well as for efficient growth in the light when acetate is supplied (mixotrophic conditions). Under these latter conditions, reduced acetate assimilation and concomitant reduced respiration occur, and biomass composition analysis reveals an increase in total fatty acid content, including neutral lipids and free fatty acids. Quantitative proteomic analysis by 14 N/15 N labelling was performed, and more than 1600 proteins were identified. These analyses reveal a strong decrease in the amounts of enzymes of the glyoxylate cycle and gluconeogenesis in parallel with a shift of the TCA cycle towards amino acid synthesis, accompanied by an increase in free amino acids. The decrease of the glyoxylate cycle and gluconeogenesis, as well as the decrease in enzymes involved in beta-oxidation of fatty acids in the icl mutant are probably major factors that contribute to remodelling of lipids in the icl mutant. These modifications are probably responsible for the elevation of the response to oxidative stress, with significantly augmented levels and activities of superoxide dismutase and ascorbate peroxidase, and increased resistance to paraquat. [less ▲]

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See detailDevelopment of a Standard Reference Material for Metabolomics Research
Phinney, K; Ballihaut, G; Bedner, M et al

in Analytical Chemistry (2013), 85(24), 11732-11738

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology ... [more ▼]

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not towards specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research. [less ▲]

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