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See detailFluorescence in astronomy
Swings, Polydore ULg

in Leaflet - Astronomical Society of the Pacific (1943), 4(175), 192-198

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See detailA Fluorescence Model for 12C13C in Comets
Rousselot, P.; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

in LPI contribution 1405 (2008)

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See detailA fluorescence model of the C[SUB]3[/SUB] radical in comets
Rousselot, P.; Arpigny, Claude ULg; Rauer, H. et al

in Astronomy and Astrophysics (2001), 368

Theoretical resonance fluorescence calculations are presented of the triatomic C[SUB]3[/SUB] radical and are compared with observations of the C[SUB]3[/SUB] emission in comets Hale-Bopp and de Vico. A ... [more ▼]

Theoretical resonance fluorescence calculations are presented of the triatomic C[SUB]3[/SUB] radical and are compared with observations of the C[SUB]3[/SUB] emission in comets Hale-Bopp and de Vico. A theoretical model of the C[SUB]3[/SUB] vibration-rotational structure in the A[SUP]1[/SUP]Pi[SUB]u[/SUB] - X[SUP]1[/SUP]Sigma[SUB]g[/SUB] [SUP]+[/SUP] electronic system is introduced. The model takes into account the detailed structure of the bending mode nu[SUB]2[/SUB] which is responsible for the emission of the 4050 à group. A total of 1959 levels are considered, with 515 levels in the ground state. The main effort is to model high-resolution spectra of the 4050 à emission in comets C/1995 O1 Hale-Bopp and 122P/1995 S1 de Vico. The agreement between observed and theoretical spectra is good for a value of the dipole moment derivative of dmu/dr ~ 2.5 Debye à [SUP]-1[/SUP]. The modeled C[SUB]3[/SUB] emission exhibits a pronounced Swings effect. Based on observations made with William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, and on observations made at the McDonald Observatory, which is operated by the University of Texas at Austin, USA. [less ▲]

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See detailA fluorescence model of the C[SUB]3[/SUB] radical in comets
Rousselot, P.; Arpigny, Claude ULg; Rauer, H. et al

in Bulletin of the American Astronomical Society (2000, October 01)

The fluorescence spectrum of the C[SUB]3[/SUB] radical in comets is investigated. A theoretical model which takes into account the rotational structure and the different vibrational levels of the bending ... [more ▼]

The fluorescence spectrum of the C[SUB]3[/SUB] radical in comets is investigated. A theoretical model which takes into account the rotational structure and the different vibrational levels of the bending mode ν [SUB]2[/SUB] involved in the emision of the 4050 à \ group, is elaborated. This model is used to interpret high-resolution spectra of some recent comets. The agreement between observed and theoretical spectra is satisfactory with some realistic assumptions on the electronic oscillator strength and the dipole moment derivative, which determine the relative importance of the rotation-vibration transitions. Different synthetic spectra which show the influence of the Swings effect and the consequences of the change in the heliocentric distance are also calculated and are presented. [less ▲]

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See detailFluorescence spectroscopy coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems.
Hammami, M.; Rouissi, H.; Salah, N. et al

in Food Chemistry (2010)

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See detailFluorescence, Absorption and Electron Spin Resonance Study of Bacteriochlorin a Incorporation into Membrane Models
Hoebeke, Maryse ULg; Damoiseau, X.; Schuitmaker, H. J. et al

in Biochimica et Biophysica Acta (1999), 1420(1-2), 73-85

Analysis of the bacteriochlorin a absorption spectra suggests the existence of a monomer-dimer equilibrium, particularly intense in phosphate buffer and favored by a decrease of the pH. The dye in ... [more ▼]

Analysis of the bacteriochlorin a absorption spectra suggests the existence of a monomer-dimer equilibrium, particularly intense in phosphate buffer and favored by a decrease of the pH. The dye in methanolic solution is predominantly in monomeric form. Fluorescence and electron spin resonance nitroxide spin labeling measurements indicate that incorporation into the lipid phase of dimyristoyl-L-alpha-phosphatidylcholine liposomes induces dye monomerization. Moreover, the molecules are bound in the external surface of the vesicles and a complete incorporation is ensured by a lipid-to-dye ratio greater than 125. [less ▲]

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See detailFluorescent labeling of degradable poly(lactide-co-glycolide) for cellular nanoparticles tracking in living cells
Freichels, Hélène; Danhier, Fabienne; Préat, Véronique et al

in International Journal of Artificial Organs (2011), 34(2), 152-160

Fluorescent-labeled aliphatic polyesters are essential materials for in vitro and in vivo studies of the behavior of these biodegradable polymers in interaction with cells or in a body. In particular, the ... [more ▼]

Fluorescent-labeled aliphatic polyesters are essential materials for in vitro and in vivo studies of the behavior of these biodegradable polymers in interaction with cells or in a body. In particular, the direct cellular localization of drug delivery systems based on these materials allows better understanding of the internalization mechanism and determination of the pharmacokinetics. Polylactide-co-glycolide (PLGA) is a rapidly degradable copolymer widely used in pharmaceutics and nanomedecine. It was prepared by ring-opening polymerization of lactide and glycolide in order to obtain a well-defined material to investigate conditions allowing the covalent linkage of a fluorescent dye (fluorescein) while preserving the macromolecular characteristics of the polymer. The success of the functionalization was ascertained by proton nuclear magnetic resonance (1H NMR), size-exclusion chromatography (SEC) and fluorescence spectroscopy. [less ▲]

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See detailFluorescent microparticle incorporation in chondrogenic cell aggregates to monitor local oxygen tension
Lambrechts, Dennis; Kerckhofs, Greet ULg; Roberts, Scott et al

in Histology and Histopathology (2011)

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See detailFluorescent oxygen sensitive microbead incorporation for measuring oxygen tension in cell aggregates.
Lambrechts, Dennis; Roeffaers, Maarten; Kerckhofs, Greet ULg et al

in Biomaterials (2013), 34(4), 922-9

Molecular oxygen is a main regulator of various cell functions. Imaging methods designed as screening tools for fast, in situ, 3D and non-interfering measurement of oxygen tension in the cellular ... [more ▼]

Molecular oxygen is a main regulator of various cell functions. Imaging methods designed as screening tools for fast, in situ, 3D and non-interfering measurement of oxygen tension in the cellular microenvironment would serve great purpose in identifying and monitoring this vital and pivotal signalling molecule. We describe the use of dual luminophore oxygen sensitive microbeads to measure absolute oxygen concentrations in cellular aggregates. Stable microbead integration, a prerequisite for their practical application, was ensured by a site-specific delivery method that is based on the interactions between streptavidin and biotin. The spatial stability introduced by this method allowed for long term measurements of oxygen tension without interfering with the cell aggregation process. By making multiple calibration experiments we further demonstrated the potential of these sensors to measure local oxygen tension in optically dense cellular environments. [less ▲]

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See detailFluorescent Pseudomonas mainly produce the dihydro form of pyoverdine at low specific growth rate.
Jacques, Philippe ULg; Ongena, MARC ULg; Bernard, F. et al

in Letters in Applied Microbiology (2003), 36(5), 259-62

AIMS: To analyse the influence of cell growth rate and iron concentration on the production of pyoverdines (PVDs) and of their reduced dihydro forms by three fluorescent Pseudomonas strains (P. putida ... [more ▼]

AIMS: To analyse the influence of cell growth rate and iron concentration on the production of pyoverdines (PVDs) and of their reduced dihydro forms by three fluorescent Pseudomonas strains (P. putida BTP16, P. fluorescens BTP7 and P. aeruginosa 7NSK2). METHODS: PVD and dihydropyoverdine (DHPVD) productions were determined by LC ESI-MS and spectrophotometry during batch and chemostat culture at different dilution rates. SIGNIFICANCE: The relatively high PVD-to-DHPVD ratio (0.57) observed in pH-controlled batch cultures suggested that a base-catalysed chemical oxidation of the dihydroform is not the prime mechanism involved in generating PVDs. Interestingly, in chemostat cultures the PVD-to-DHPVD ratio was significantly reduced at low specific growth rate. Our results suggest that the oxidation of DHPVD to PVD is catalysed by an iron-dependent enzymatic reaction rather than a chemical oxidation. [less ▲]

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See detailFluorescent reporter libraries as useful tools for optimizing microbial cell factories: a review of the current methods and applications
Delvigne, Frank ULg; Pêcheux, Hélène; Tarayre, Cédric ULg

in Frontiers in Bioengineering and Biotechnology (2015), 3

The use of genetically encoded fluorescent reporters allows speeding up the initial optimization steps of microbial bioprocesses. These reporters can be used for determining the expression level of a ... [more ▼]

The use of genetically encoded fluorescent reporters allows speeding up the initial optimization steps of microbial bioprocesses. These reporters can be used for determining the expression level of a particular promoter, not only the synthesis of a specific protein but also the content of intracellular metabolites. The level of protein/metabolite is thus proportional to a fluorescence signal. By this way, mean expression profiles of protein/ metabolites can be determined non-invasively at a high-throughput rate, allowing the rapid identification of the best producers. Actually, different kinds of reporter systems are available, as well as specific cultivation devices allowing the on-line recording of the fluorescent signal. Cell-to-cell variability is another important phenomenon that can be integrated into the screening procedures for the selection of more efficient microbial cell factories. [less ▲]

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See detailFluorescent tagging of VP22 in N-terminus reveals that VP22 favors Marek’s disease virus (MDV) virulence in chickens and allows morphogenesis study in MD tumor cells
Remy, Sylvie; Blondeau, Caroline ULg; Le Vern, Yves et al

in Veterinary Research (2013)

Marek’s disease virus (MDV) is an alpha-herpesvirus causing Marek’s disease in chickens, mostly associated with T-cell lymphoma. VP22 is a tegument protein abundantly expressed in cells during the lytic ... [more ▼]

Marek’s disease virus (MDV) is an alpha-herpesvirus causing Marek’s disease in chickens, mostly associated with T-cell lymphoma. VP22 is a tegument protein abundantly expressed in cells during the lytic cycle, which is essential for MDV spread in culture. Our aim was to generate a pathogenic MDV expressing a green fluorescent protein (EGFP) fused to the N-terminus of VP22 to better decipher the role of VP22 in vivo and monitor MDV morphogenesis in tumors cells. In culture, rRB-1B EGFP22 led to 1.6-fold smaller plaques than the parental virus. In chickens, the rRB-1B EGFP22 virus was impaired in its ability to induce lymphoma and to spread in contact birds. The MDV genome copy number in blood and feathers during the time course of infection indicated that rRB-1B EGFP22 reached its two major target cells, but had a growth defect in these two tissues. Therefore, the integrity of VP22 is critical for an efficient replication in vivo, for tumor formation and horizontal transmission. An examination of EGFP fluorescence in rRB-1B EGFP22-induced tumors showed that about 0.1% of the cells were in lytic phase. EGFP-positive tumor cells were selected by cytometry and analyzed for MDV morphogenesis by transmission electron microscopy. Only few particles were present per cell, and all types of virions (except mature enveloped virions) were detected unequivocally inside tumor lymphoid cells. These results indicate that MDV morphogenesis in tumor cells is more similar to the morphorgenesis in fibroblastic cells in culture, albeit poorly efficient, than in feather follicle epithelial cells [less ▲]

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See detailFluoride for the treatment of osteoporosis
Reginster, Jean-Yves ULg

in Annals of Internal Medicine (1999), 130

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See detailFluoride PET-CT.
Hustinx, Roland ULg; Beckers, Catherine ULg

in Fanti, Stefano; Farsad, Mohsen; Mansi, Luigi (Eds.) PET-CT Beyond FDG. (2010)

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See detailFluoride salts compared to calcium-vitamin D in the treatment of established osteoporosis: The FAVOS study
Meunier, PJ; Sebert, JL; Reginster, Jean-Yves ULg et al

in Osteoporosis International (1996), 6(S1), 251

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See detailFluorinated alcohols as activators for the solvent-free chemical fixation of carbon dioxide onto epoxides
Gennen, Sandro ULg; Alves, Margot ULg; Méreau, Raphaël et al

in ChemSusChem (2015), 8(11), 1845-1849

The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 onto epoxides under mild experimental conditions. The combination of online ... [more ▼]

The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 onto epoxides under mild experimental conditions. The combination of online kinetic studies, NMR titrations and DFT calculations allows understanding this synergistic effect that provides an active organocatalyst for CO2/epoxides coupling. [less ▲]

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See detailFluorinated analogs of nucleosides and fluorinated tracers of gene expression for positron emission tomography
Couturier, Olivier; Chatal, Jean-François; Hustinx, Roland ULg

in Bulletin du Cancer (2004), 91(9), 695-703

F-18-FDG is currently the only fluorinated tracer used in routine clinical positron emission tomography (PET). Fluorine 18 is considered as the ideal radioisotope for PET, thanks to a low positron energy ... [more ▼]

F-18-FDG is currently the only fluorinated tracer used in routine clinical positron emission tomography (PET). Fluorine 18 is considered as the ideal radioisotope for PET, thanks to a low positron energy, which not only limits the dose rate to the patients but also provides high-resolution images. Furthermore, the 110 min. physical half-life allows for high-yield radiosynthesis, transport from the production site to the imaging site, and imaging protocols that could span hours, which permits dynamic studies and assessing metabolic processes that may be fairly slow Recently, synthesis of fluorinated tracers from prosthetic group precursors, which allows easier radiolabeling of biomolecules, has given a boost to the development of numerous fluorinated tracers, Given the wide availability of fluorine 18, such tracers may well develop into important routine tracers. This article is a review of the literature concerning fluorinated analogs of nucleosides and fluorinated radiotracers of gene expression recently developed and under investigation. [less ▲]

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