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See detailIn situ analysis of lipid oxidation in oilseedbased food products using near-infrared spectroscopy and chemometrics: The sunflower kernel paste (tahini) example
Mureșan; Danthine, Sabine ULg; Mureșan, Andruța Elena et al

in Talanta (2016), 155

A new near-infrared (NIR) spectroscopic method was developed for the analytical measurement of lipid oxidation in sunflower kernel paste (tahini), which was chosen as an example of a complex oilseed-based ... [more ▼]

A new near-infrared (NIR) spectroscopic method was developed for the analytical measurement of lipid oxidation in sunflower kernel paste (tahini), which was chosen as an example of a complex oilseed-based food product. The NIR spectra of sunflower tahini were acquired for the extracted fat phase (EFP) and for the intact sunflower tahini (IST) samples during controlled storage. The best peroxide value (PV) calibration models were considered suitable for quality control (ratio of performance of deviation [RPD] >5). The best PV partial least squares (PLS) model result for EFP (RPD 6.36) was obtained when using standard normal variate (SNV) and the Savitzky-Golay first derivative in the 1140-1184 nm, 1388-1440 nm and 2026-2194 nm regions. In the case of IST spectra, the best PV models (RPD 5.23) were obtained when either multiple scattering correction (MSC) or SNV were followed by the Savitzky-Golay second derivative for the 1148-1180 nm and 2064-2132 nm regions. There were poor correlations between the NIR-predicted values and the reference data of the panisidine value (pAV) for both EFP and IST. Overall, the results obtained showed that NIR spectroscopy is an appropriate analytical tool for monitoring sunflower paste PV in situ. Due to the nonexistence of the extraction step, it demonstrates a unique and substantial advantage over presently known methods. Based on these results it is strongly recommended that, when using NIR PLS models to assess lipid oxidation in situ in similar oilseedbased food products (e.g., sesame tahini, hazelnut and cocoa liquor used for chocolate production, peanut butter, hazelnut, almond, pistachio spreads), suitable calibration sets containing samples of different particle sizes and stored at different temperatures be selected. [less ▲]

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See detailIn situ and laboratory mechanical characterization of a loess sequence from Middle Belgium
Delvoie, Simon ULg; Charlier, Robert ULg; Collin, Frédéric ULg

Conference (2016, May 25)

A 10 m thick loess (aeolian silt) layer located beside the Romont quarry (Eben-Emael, Middle Belgium) has been investigated in order to characterize the mechanical behaviour of the silty material. Cone ... [more ▼]

A 10 m thick loess (aeolian silt) layer located beside the Romont quarry (Eben-Emael, Middle Belgium) has been investigated in order to characterize the mechanical behaviour of the silty material. Cone penetration tests (CPT) have been performed with different cones (M1-type, M2-type and electric) in order to evaluate the influence of the cone on the mechanical behaviour interpretation. Concurrently, laboratory tests have been performed on undisturbed samples from core drillings. Laboratory tests consist of a physical characterization (grain size distribution, Atterberg limits) and a mechanical characterization (oedometer tests). This comprehensive investigation study focuses on the comparison of the loess characterization between in situ and laboratory approaches. CPT-based soil behaviour type charts are analyzed and compared with the Unified Soil Classification System. Many relations also exist in the literature between parameters obtained from CPT results and from laboratory tests. The study explores the existing relations between the cone resistance and the oedometer constrained modulus in order to verify the related coefficients proposed in the literature for silty material. [less ▲]

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See detailIn situ aortic allograft insertion to repair a primary aortoesophageal fistula due to thoracic aortic aneurysm
Pirard, Laurence ULg; Creemers, Etienne ULg; Van Damme, Hendrik ULg et al

in Vascular Surgery (2005), 42

Aortoesophageal fistula due to thoracic aortic aneurysm is an uncommon cause of gastrointestinal bleeding and has an extremely poor prognosis. In the English literature, we found only 27 successfully ... [more ▼]

Aortoesophageal fistula due to thoracic aortic aneurysm is an uncommon cause of gastrointestinal bleeding and has an extremely poor prognosis. In the English literature, we found only 27 successfully managed cases of primary aortoesophageal fistula due to thoracic aortic aneurysm. We present a case of 74-year-old man who experienced the erosion of a thoracoabdominal aortic aneurysm into the esophagus. We successfully performed resection and replacement of the thoracoabdominal aorta with a cryopreserved allograft and total thoracic esophagectomy. A few months later, the esophagus was reconstructed with orthotopic colonic interposition. The patient recovered well and resumed a normal life (12 months’ follow-up). [less ▲]

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See detailIn situ bidentate to tetradentate ligand exchange reaction in cobalt-mediated radical polymerization
Kermagoret, Anthony ULg; Jérôme, Christine ULg; Detrembleur, Christophe ULg et al

in European Polymer Journal (2015), 62

Organometallic-mediated radical polymerization (OMRP) has seen a significant growth in the last years notably due to the development of new metal complexes, especially cobalt derivatives. Despite of this ... [more ▼]

Organometallic-mediated radical polymerization (OMRP) has seen a significant growth in the last years notably due to the development of new metal complexes, especially cobalt derivatives. Despite of this, none of the reported complexes offers optimal control for monomers with very different reactivity, which somewhat limits the synthesis of copolymers. In order to expand the scope of cobalt-mediated radical polymerization (CMRP), we investigated an in situ ligand exchange reaction for modulating the properties of the cobalt complex at the polymer chain-end and adjusting the C-Co bond strength involved in the control process. With the aim of improving the synthesis of poly(vinyl acetate)-b-poly(n-butyl acrylate) copolymers, bidentate acetylacetonate ligands, which impart high level of control to the polymerization of vinyl acetate (VAc), were replaced in situ at the PVAc-cobalt chain-end by tetradentate Salen type ligands that are more suited to acrylates. [less ▲]

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See detailIn situ characterization in freeze-fractured mouse thymuses of lymphoepithelial complexes ultrastructurally similar to isolated thymic nurse cells.
Defresne, Marie-Paule ULg; Goffinet, Gerhard ULg; Boniver, Jacques ULg

in Tissue & Cell (1986), 18(3), 321-30

Scanning and transmission electron microscopy of the cracked surfaces of cryofractured pre-fixed C57BL/Ka mouse thymus reveals the existence of cell complexes, distinct from the surrounding cell ... [more ▼]

Scanning and transmission electron microscopy of the cracked surfaces of cryofractured pre-fixed C57BL/Ka mouse thymus reveals the existence of cell complexes, distinct from the surrounding cell organization, in which groups of lymphocytes are delimited by large cytoplasmic sheets or envelopes. These complexes, located in the subcapsular and cortical regions, display morphological features similar to that of the thymic nurse cells (TNCs), which can be isolated from the mouse or human thymus enzymatically dissociated. They can be considered as dynamic systems able to modify their three-dimensional organization, namely with regard to intrathymic cellular traffic involved in T-lymphocyte maturation. [less ▲]

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See detailIn situ conservation of wild populations of Phaseolus lunatus in the Central Valley of Costa Rica.
Maquet, A.; Baudoin, Jean-Pierre ULg

in Report of a Working Group on Grain Legumes. Third meeting, Krakow,Poland, 5-7 July 2001 (2002)

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See detailIn situ demonstration of germinal cell apoptosis during diethylstilbestrol-induced testis regression in adult male syrian hamsters
Nonclercq, D.; Reverse, D.; Toubeau, G. et al

in Biology of Reproduction (1996), 55(6), 1368-1376

Testis regression was induced in male Syrian hamsters by chronic exposure to diethylstilbestrol (DES), an estradiol-1713 agonist. Experimental groups (n = 4-5) were killed at increasing time intervals ... [more ▼]

Testis regression was induced in male Syrian hamsters by chronic exposure to diethylstilbestrol (DES), an estradiol-1713 agonist. Experimental groups (n = 4-5) were killed at increasing time intervals over a period of 6 mo after initiation of treatment. Apoptosis in testes was demonstrated by in situ analysis of DNA fragmentation. Cell proliferation was monitored by immunostaining nuclei of S-phase cells after pulse labeling with 5-bromo-2'-deoxyuridine. Levels of FSH and testosterone, measured by RIA, fell rapidly in DES-treated hamsters. In parallel, testis weight and seminiferous tubule area underwent an 80% decrease during the first 2 wk of DES administration. The composition of seminiferous epithelium was also drastically affected by DES, since it became progressively confined to Sertoli cells, spermatogonia, and spermatocytes. Testis regression was associated with an important increase of apoptosis, which started 3 days after the beginning of DES administration. Apoptosis was still 10- to 50-fold higher than in control testes by the end of treatment; it affected primarily spermatocytes and, to a much lesser extent, spermatogonia. Cell proliferation was not inhibited by chronic DES administration. In conclusion, these data indicate that apoptosis can by itself account for estrogen-induced testis regression. [less ▲]

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See detailIn situ development and application of cDNA-AFLP to isolate genes of Candida oleophila (strain O) potentially involved in antagonistic properties against Botrytis cinerea.
Massart, Sébastien ULg; Luna-Guarda, M.; Jijakli, Haissam ULg

in Communications in agricultural and applied biological sciences (2004), 69(4), 595-599

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See detailIn situ dynamic analysis of solid or aqueous solutions undergoing chemical reactions by RBS or PIXE with external beam
Bouquillon, A.; Dran, J*-C; Lagarde, G. et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2002), 188

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See detailIn situ filtration responses of Daphnia galeata to changes in food quality
Darchambeau, François ULg; Thys, I.

in Journal of Plankton Research (2005), 27(3), 227-236

In the stoichiometric study of phyto-zooplankton interactions, a controversy exists about how Daphnia species regulate their feeding rate when submitted to low-quality food (i.e. high dietary carbon ... [more ▼]

In the stoichiometric study of phyto-zooplankton interactions, a controversy exists about how Daphnia species regulate their feeding rate when submitted to low-quality food (i.e. high dietary carbon:phosphorus [C:P] ratio). In this study, we gathered data over 3 years on in situ clearance rates of a Daphnia galeata population, by conducting grazing experiments from April 1998 to October 2000 in the Esch-sur-Sure reservoir (Grand-Duchy of Luxembourg). Observed clearance rates (2.5-13.5 mL individual(-1) day(-1), mean 7.0 mL individual(-1) day(-1)) were correlated with population and environmental variables. Mean body size of Daphnia individuals was the best predictor of clearance rate (r(2) = 0.639), followed by water temperature (r(2) = 0.262) and P concentration in the seston (r(2) <= 0.241). When combined with body size, seston C:P or nitrogen:P ratios provided the best predictive regression model of clearance rate (r(2) = 0.852-0.897). The clearance rate was always correlated negatively with P concentration in the food. Thus, Daphnia reacts to a decrease of food quality (i.e. higher C:P ratio) by an increase of its feeding rate. However, the filtration response to food quality was inhibited by high population density. We suggest that, when food quality is low and population density high, this inhibition may favour fitness of future conspecific generations. In conclusion, our results emphasize the effect of P availability on transfer rate of organic matter between lacustrian autotrophs and herbivores and pose questions about consequent effects on nutrient biogeochemical cycles. [less ▲]

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See detailIn situ follow-up of adsorption in activated carbon beds using X-ray microtomography
Almazan, Maria del Carmen; Léonard, Angélique ULg; Toye, Dominique ULg et al

in Kaskel, S.; Llewellyn, P.; Rodriguez-Reinoso, F. (Eds.) et al Characterisation of Porous Solids VII - Proceedings of the 8th International Symposium on the Characterisation of Porous Solids (2009)

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See detailThe in situ formation of a new initiator system for the syndiotactic anionic polymerization of methyl methacrylate in toluene at 0°C
Zundel, Thomas; Teyssié, Philippe; Jérôme, Robert ULg

in Polymer (2002), 43(25), 7191-7193

This paper reports on an efficient 'in-situ' one pot synthesis of an initiatior/ligand adduct, which can be used to initiate the anionic polymerization of methyl methacrylate in toluene at 0 °C ... [more ▼]

This paper reports on an efficient 'in-situ' one pot synthesis of an initiatior/ligand adduct, which can be used to initiate the anionic polymerization of methyl methacrylate in toluene at 0 °C. Predominantly syndiotactic PMMA is formed. [less ▲]

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See detailIn situ formation of stabilizers for the implementation of dispersion nitroxide mediated polymerization of MMA in supercritical carbon dioxide
Grignard, Bruno ULg; Gigmes, Didier; Jérôme, Christine ULg et al

Poster (2009, September 17)

Controlled dispersion Nitroxide Mediated Polymerization (NMP) of methyl methacrylate (MMA) was successfully carried out for the first time in supercritical carbon dioxide (scCO2) in the presence of CO2 ... [more ▼]

Controlled dispersion Nitroxide Mediated Polymerization (NMP) of methyl methacrylate (MMA) was successfully carried out for the first time in supercritical carbon dioxide (scCO2) in the presence of CO2-philic perfluorinated surfactant that was generated “in situ”. The control of the MMA polymerization relies on the strategy developed by Charleux et al. that consists of using a SG1-based alkoxyamine, i.e. the block-builder, in the presence of small amount of styrene. In a first step, CO2 soluble polyheptadecafluorodecylacrylate was prepared in scCO2 using block-builder as an alkoxyamine. In a second step, nitroxide SG1 mediated dispersion polymerization of MMA was conducted at 70°C and 300 bar in the presence of 5 w% of SG1 terminated surfactant compared to the monomer. Different monomer to alkoxyamine molar ratios were investigated in order to target different molecular weights. In each case, the monomer conversion was high (>90 %), the experimental molecular weight was in good agreement with the theoretical value and the polydispersity was narrow (Mw/Mn ~1.2). Moreover, after depressurisation of the cell, PMMA was collected as a free flowing powder consisting of small sized microspheres. [less ▲]

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See detailIn situ formation of yttrium alkoxides: A versatile and efficient catalyst for the ROP of epsilon-caprolactone
Martin, Eric; Dubois, Philippe ULg; Jérôme, Robert ULg

in Macromolecules (2003), 38(16), 5934-5941

[Tris(hexamethyldisilyl)amide] yttrium is a catalyst for the controlled ring-opening polymerization of epsilon-caprolactone when reacted with an excess of alcohol. Up to an alcohol-to-yttrium molar ratio ... [more ▼]

[Tris(hexamethyldisilyl)amide] yttrium is a catalyst for the controlled ring-opening polymerization of epsilon-caprolactone when reacted with an excess of alcohol. Up to an alcohol-to-yttrium molar ratio of 50, the chain transfer to the alcohol is quantitative, and the molecular weight of the chains can be predicted from the monomer-to-alcohol molar ratio. At alcohol-to-yttrium ratios higher than 100, the alcohol is quantitatively consumed provided that 1,1,1,3,3,3-hexamethyldisilazane, which is formed as a byproduct, is removed from the reation medium. Depending on the structure of the alcohol, end-functional polyesters can be prepared (e.g., with N-pyrrolyl and 3-thienyl end groups). Well-defined block and random copolymers of epsilon-CL with lactides and gamma-bromo-epsilon-caprolactone, respectively, have also been synthesized. Compared to aluminum alkoxides, the in situ formed yttrium alkoxides have the advantage of a much faster polymerization kinetics while preserving control. [less ▲]

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See detailIn situ FTIR micro-spectroscopy to investigate polymeric fibers under supercritical carbon dioxide: CO2 sorption and swelling measurements
Champeau, Mathilde; Thomassin, Jean-Michel ULg; Jérôme, Christine ULg et al

in Journal of Supercritical Fluids (2014), 90

An original experimental set-up combining a FTIR (Fourier Transformed InfraRed) microscope with a high pressure cell has been built in order to analyze in situ and simultaneously the CO2 sorption and the ... [more ▼]

An original experimental set-up combining a FTIR (Fourier Transformed InfraRed) microscope with a high pressure cell has been built in order to analyze in situ and simultaneously the CO2 sorption and the polymer swelling of microscopic polymer samples, such as fibers, subjected to supercritical carbon dioxide. Thanks to this experimental set-up, we have determined as a function of the CO2 pressure (from 2 to 15 MPa) the CO2 sorption and the polymer swelling at T = 40 °C of four polymer samples, namely PEO (polyethylene oxide), PLLA (poly-l-lactide acid), PET (polyethylene terephtalate) and PP (polypropylene). The quantity of CO2 sorbed in all the studied polymers increases with pressure. PEO and PLLA display a significant level of CO2 sorption (20 and 25% respectively, at P = 15 MPa). However, we observe that a lower quantity of CO2 can be sorbed into PP and PET (7 and 8% respectively, at P = 15 MPa). Comparing their thermodynamic behaviors and their intrinsic properties, we emphasize that a high CO2 sorption can be reach if on one hand, the polymer is able to form specific interaction with CO2 in order to thermodynamically favor the presence of CO2 molecules inside the polymer and on the other, displays high chains mobility in the amorphous region. PLLA and PEO fulfilled these two requirements whereas only one property is fulfilled by PET (specific interaction with CO2) and PP (high chains mobility). Finally, we have found that for a given CO2 sorption, the resulting swelling of the polymer depends mainly on its crystallinity. [less ▲]

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