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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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See detailThe in situ Glyptostroboxylon forest of Hoegaarden (Belgium) at the Initial Eocene Thermal Maximum (55 Ma)
Fairon-Demaret, Muriel ULg; Steurbaut, Etienne; Damblon, Freddy ULg et al

in Review of Palaeobotany and Palynology (2003), 126(1-2), 103-129

Hundreds of silicified standing stumps have been discovered within a lignitic horizon in the middle of the Tienen Formation near Hoegaarden in northeast Belgium. The anatomical features of the fossil ... [more ▼]

Hundreds of silicified standing stumps have been discovered within a lignitic horizon in the middle of the Tienen Formation near Hoegaarden in northeast Belgium. The anatomical features of the fossil stumps, as those of the numerous silicified secondary xylem remains collected since the last century from this area, demonstrate that they all belong to a single taxodiaceous taxon. The stumps bear characteristics shared by Taxodioxylon gypsaceum and Glyptostroboxylon tenerum, but affinities with the latter appear closer. They are attributed to Glyptostroboxylon sp. Calibration of the sedimentological, stratigraphical and organic carbon isotope data reveals that these taxodiaceous fossil trees developed in a swampy lowland environment most probably during the Initial Eocene Thermal Maximum at ca. 55 Ma. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailIn situ hybridization at the electron microscope level: an improved method for precise localization of ribosomal DNA and RNA.
Thiry, Marc ULg; Thiry-Blaise, L.

in European Journal of Cell Biology (1989), 50(1), 235-43

In situ hybridization using biotinylated rDNA probes and secondary antibody coupled to gold particles was developed on ultrathin sections of Lowicryl-embedded Ehrlich tumor cells for precise localization ... [more ▼]

In situ hybridization using biotinylated rDNA probes and secondary antibody coupled to gold particles was developed on ultrathin sections of Lowicryl-embedded Ehrlich tumor cells for precise localization of ribosomal RNA (rRNA) and ribosomal DNA (rDNA). For the detection of rDNA, an immunocytochemical approach involving an antibody against single-stranded DNA was used in order to determine the more efficient denaturation procedure. Using this technique, rDNA can be visualized in the fibrillar centers of nucleoli, especially in their peripheral regions at the proximity of both the dense fibrils and the nucleolar interstices as well as within the latter. rDNA was occasionally detected in some clumps of dense nucleolus-associated chromatin. Besides the presence of rRNA in the ribosome-rich cytoplasmic areas and in the dense fibrillar component and the granular component of the nucleolus, rRNA was also found in the fibrillar center areas close to the boundary region to the dense fibrillar component. These results are discussed in the light of the present knowledge on the functional organization of the nucleolus. [less ▲]

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See detailIn situ investigation of scCO2 assisted impregnation of drug into polymer by high pressure FTIR micro-spectroscopy
Champeau, Mathilde ULg; Thomassin, Jean-Michel ULg; Jérôme, Christine ULg et al

in Analyst (2015), 140(3), 869-879

An original experimental set-up combining a FTIR microscope with a high pressure cell has been built in order to analyze in-situ the impregnation of solute into microscopic polymer samples, such as fibers ... [more ▼]

An original experimental set-up combining a FTIR microscope with a high pressure cell has been built in order to analyze in-situ the impregnation of solute into microscopic polymer samples, such as fibers or films, subjected to supercritical CO2. Thanks to this experimental set-up, key factors governing the impregnation process can be simultaneously followed such as the swelling of the polymeric matrix, the CO2 sorption, the kinetic of impregnation and the drug loading into the matrix. Moreover, the solute/polymer interactions and the speciation of the solute can be analyzed. We have monitored in situ the impregnation of aspirin and ketoprofen into PEO (Polyethylene Oxide) platelets at T=40°C and P=5; 10 and 15 MPa. The kinetic of impregnation of aspirin was quicker than the one of ketoprofen and the final drug loading was also higher in case of aspirin. Whereas the CO2 sorption and the PEO swelling remain constant when PEO is just subjected to CO2 under isobaric conditions, we noticed that both parameters can increase while the drug impregnates PEO. Coupling these results with DSC measurements, we underlined the plasticizing effect of the drug that also leads to decrease the crystallinity of PEO in situ thus favoring the sorption of CO2 molecules into the matrix and the swelling of the matrix. The plasticizing effect increases with the drug loading. Finally, the speciation of drug was investigated considering the shift of the carboxyl bands of the drugs. Both drugs were found to be mainly homogeneously dispersed into PEO. [less ▲]

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See detailIn Situ Lipidomic Analysis of Nonalcoholic Fatty Liver by Cluster TOF-SIMS Imaging
Debois, Delphine ULg; Bralet, Marie-Pierre; Le Naour, François et al

in Analytical Chemistry (2009), 81(8), 2823-2831

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See detailIn situ localisation and quantification of surfactins in a Bacillus subtilis swarming community by imaging mass spectrometry
Debois, Delphine ULg; Hamzé, Kassem; Guérineau, Vincent et al

in Proteomics (2008), 8(18), 3682-3691

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See detailIN SITU MEASUREMENTS OF METAZOOPLANKTON PREDATION ON PROTOZOOPLANKTON: USE OF FLUORESCENTLY LABELLED PROTISTS.
Joaquim-Justo, Célia ULg; Caufman, F; Thomé, Jean-Pierre ULg

Poster (2001, February 04)

The importance of trophic relationships between metazooplankton and protozoans in rivers are not yet well known, but as some authors have shown during the last decade, the predation exerted by ... [more ▼]

The importance of trophic relationships between metazooplankton and protozoans in rivers are not yet well known, but as some authors have shown during the last decade, the predation exerted by metazooplankton on these organisms might be of importance in the transfer of energy from the pico- and nanoplankton to the metazooplankton. Fluorescent carboxylate microspheres of 0.5 µm in diameter were used to label natural protozooplankton. Different combinations of labelling times and concentrations of microspheres were tested to achieve an optimal labelling of the protists (i.e. a maximal proportion of individuals labelled with an identical number of microspheres); the most appropriate labelling conditions were with short incubations (10 minutes) and relatively low microsphere concentrations (1.105 FMP/ml). Live labelled protozooplankton was used to determine ingestion rates of the natural metazooplankton of the river Meuse (Belgium). It could be showed for all abundant species (i.e. the rotifers Brachionus calyciflorus, Brachionus angularis and Keratella cochlearis) that the predation exerted on protozooplankton was high (from 34 to 182 protists.rotifer-1.h-1) in in situ conditions. [less ▲]

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See detailIn situ measurements of the nitrogen assimilation by marine plants using 15N (Gulf of Calvi-Corsica)
Millet, Sylvie; Nyssen, Fabienne; Lepoint, Gilles ULg et al

Poster (1997, September)

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See detailIn situ measurements of the static liquid holdup in Katapak-SP12 (TM) packed column using X-ray tomography
Aferka, Saïd ULg; Crine, Michel ULg; Saroha, A. K. et al

in Chemical Engineering Science (2007), 62(21), 6076-6080

Static liquid holdup was determined in situ, in a column packed with Katapak-SP12 (TM) elements, using a non-intrusive X-ray tomographic technique. Experiments were performed in a 10 cm diameter PVC ... [more ▼]

Static liquid holdup was determined in situ, in a column packed with Katapak-SP12 (TM) elements, using a non-intrusive X-ray tomographic technique. Experiments were performed in a 10 cm diameter PVC column with the air-water system. The technique allows a local determination of the various liquid holdup as well as of the capillary height, without dismantling the elements. Results are in good agreement with correlations proposed in the literature. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailIn situ nick translation at the electron microscopic level
Thiry, Marc ULg

in Didenko, V V (Ed.) Methods in molecular biology. In situ detection of DNA damage: methods and protocols (2002)

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See detailIn situ nick translation at the electron microscopic level: a tool for studying the location of DNAse I-sensitive regions within the cell.
Thiry, Marc ULg

in Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society (1991), 39(6), 871-4

The in situ nick translation method was adapted to the ultrastructural level, to study the location of DNAse I-sensitive sequences within the cell. Ultra-thin sections of Lowicryl-embedded cells were ... [more ▼]

The in situ nick translation method was adapted to the ultrastructural level, to study the location of DNAse I-sensitive sequences within the cell. Ultra-thin sections of Lowicryl-embedded cells were incubated in a medium containing DNAse I, DNA polymerase I, and all four deoxyribonucleotides, some being biotinylated. The nick-translated sites were then visualized by an indirect immunogold labeling technique. The resulting labeling pattern is closely dependent on the DNAse I concentration in the nick-translation medium. The method reveals with great precision the specific DNAse I-sensitive regions within the nucleus. This technique can be used to discriminate between active and inactive regions of interphase chromatin. [less ▲]

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See detailIn situ nitroxide-mediated polymerization of styrene promoted by the N-tert-butyl-alpha-isopropylnitrone/BPO pair: ESR investigations
Detrembleur, Christophe ULg; Clément, Jean-Louis; Sciannaméa, Valérie et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2013), 51(8), 1786-1795

The styrene polymerization initiated by benzoyl peroxide (BPO) in the presence of N-tert-butyl--isopropylnitrone as nitroxide precursor is well-controlled provided that a prereaction between the nitrone ... [more ▼]

The styrene polymerization initiated by benzoyl peroxide (BPO) in the presence of N-tert-butyl--isopropylnitrone as nitroxide precursor is well-controlled provided that a prereaction between the nitrone and BPO is carried out in suitable conditions prior to polymerization at a higher temperature. Electron spin resonance (ESR) spectroscopy was implemented to probe the nitroxides formed during both steps, that is, the prereaction and polymerization, and to get crucial information regarding the structure of the nitroxides responsible for the polymerization control. ESR studies combined with first principles calculations have evidenced that nitroxides observed during the prereaction in the presence of styrene and during the polymerization steps consist of a mixture of two macronitroxides. One is formed by the addition of a growing polystyrene chain to the nitrone as would be expected. However, the second one results from the addition of a polystyrene chain to tert-butyl nitroso that is in situ formed presumably by decomposition of the first macronitroxide type. [less ▲]

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