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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 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 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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See detailFluorinated tracers for imaging cancer with positron emission tomography
Couturier, Olivier; Luxen, André ULg; Chatal, Jean-François et al

in European Journal of Nuclear Medicine and Molecular Imaging (2004), 31(8), 1182-1206

2-[F-18]fluoro-2-deoxy-D-glucose (FDG) is currently the only fluorinated tracer used in routine clinical positron emission tomography (PET). Fluorine-18 is considered the ideal radioisotope for PET ... [more ▼]

2-[F-18]fluoro-2-deoxy-D-glucose (FDG) is currently the only fluorinated tracer used in routine clinical positron emission tomography (PET). Fluorine-18 is considered the ideal radioisotope for PET imaging owing to the low positron energy (0.64 MeV), which not only limits the dose rate to the patient but also results in a relatively short range of emission in tissue, thereby providing high-resolution images. Further, the 110-min physical half-life allows for high-yield radiosynthesis, transport from the production site to the imaging site and imaging protocols that may span hours, which permits dynamic studies and assessment of potentially fairly slow metabolic processes. The synthesis of fluorinated tracers as an alternative to FDG was initially tested using nucleophilic fluorination of the molecule, as performed when radiolabelling with iodine-124 or bromide-76. However, in addition to being long, with multiple steps, this procedure is not recommended for bioactive molecules containing reactive groups such as amine or thiol groups. Radiochemical yields are also often low. More recently, radiosynthesis from prosthetic group precursors, which allows easier radiolabelling of biomolecules, has led to the development of numerous fluorinated tracers. Given the wide availability of 18F, such tracers may well develop into important routine tracers. This article is a review of the literature concerning fluorinated radiotracers recently developed and under investigation for possible PET imaging in cancer patients. Two groups can be distinguished. The first includes "generalist" tracers, i.e. tracers amenable to use in a wide variety of tumours and indications, very similar in this respect to FDG. These are tracers for non-specific cell metabolism, such as protein synthesis, amino acid transport, nucleic acid synthesis or membrane component synthesis. The second group consists of "specific" tracers for receptor expression (i.e. oestrogens or somatostatin), cell hypoxia or bone metabolism. [less ▲]

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See detailFluorine in the atmosphere: Inorganic fluorine budget and long-term trends based on FTIR measurements at Jungfraujoch
Duchatelet, Pierre ULg

Doctoral thesis (2011)

High resolution solar spectra are routinely recorded since more than two decades by the University of Liège at the International Scientific Station of the Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580 m ... [more ▼]

High resolution solar spectra are routinely recorded since more than two decades by the University of Liège at the International Scientific Station of the Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580 m asl) with Fourier Transform Infrared (FTIR) spectrometers. Over the last years, major improvements have been implemented in the algorithms used to retrieve the abundances of atmospheric constituents accessible to the FTIR technique. Now, in addition to total column, information on the vertical distribution of the target gas is often available, allowing producing partial column data sets. We take advantage of these improvements to generate and characterize long-term total and partial columns time series of some important inorganic fluorinated trace gases deduced from FTIR measurements performed at Jungfraujoch. First, our investigations on hydrogen fluoride (HF) indicate that the adoption of a Galatry line shape model for this species significantly improves the fitting quality of the retrievals. The sensitivity of our FTIR measurements to HF inversions in three distinct regions that range from the low to the high stratosphere is confirmed thanks to products derived from two satellites and from two numerical models. We further demonstrate that the HF seasonal variations that occur in the low stratosphere are mainly responsible for the seasonal cycle observed in our HF total column time series. We have also developed an original multi-spectrum multi-window retrieval strategy allowing to derive, for the first time, some information on the vertical distribution of carbonyl fluoride (COF2) from ground-based FTIR measurements. After comparison with model data, our COF2 and HF FTIR datasets are combined to assess the atmospheric inorganic fluorine burden Fy. A trend analysis of our HF, COF2 and Fy time series is then performed for four different time periods spanning the 1985-2010 time interval. While we observe a recent stabilization for HF, corresponding COF2 data show a significant rise, after a period of significant reduction in its accumulation rate. This is probably ascribable to the combination of the decrease of its main source gas CFC-12 with the increase of the substitute product HCFC-22. However, this increase in the COF2 rate of change does not significantly impact the Fy trend, which is essentially driven by the change in HF. In addition, we show that the partitioning between the two major fluorine reservoirs HF and COF2 has not changed since the beginning of this century. Together, they account for around 95% of total inorganic fluorine in the atmosphere. Finally, we study the long-term evolution of carbon tetrafluoride (CF4), for the first time from ground-based FTIR measurements. The trend analysis of our time series indicates a slowing, initiated during the nineties, in the CF4 growth rate despite the fact that the absolute loading of this compound is still increasing. Our linear accumulation rates are consistent with those deduced from space or surface measurements. [less ▲]

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See detailFluorine-18 deoxyglucose positron emission tomography for the detection of bone metastases in patients with non-small cell lung cancer
Bury, Thierry ULg; BARRETO, A.; Daenen, Frédéric ULg et al

in European Journal of Nuclear Medicine (1998), 9

Despite advances in morphological imaging, some patients with lung cancer are found to have non resectable disease at surgery or die of recurrence within a year of surgery. At present, metastatic bone ... [more ▼]

Despite advances in morphological imaging, some patients with lung cancer are found to have non resectable disease at surgery or die of recurrence within a year of surgery. At present, metastatic bone involvement is usually assessed using bone scintigraphy, which has a high sensitivity but a poor specificity. We have attempted to evaluate the utility of the fluorine-18 deoxyglucose positron emission tomography (FDG PET) for the detection of bone metastasis. One hundred and ten consecutive patients with histological diagnosis of non-small cell lung cancer (NSCLC) who underwent both FDG PET and bone scintigraphy were selected for this review. In this group, there were 43 patients with metastatic disease (stage IV). Among these. 21 (19% of total group) had one or several bone metastases confirmed by biopsy (n = 8) or radiographic techniques (n = 13). Radionuclide bone scanning correctly identified 54 out of 89 cases without osseous involvement and 19 out of 21 osseous involvements. On the other hand, FDG PET correctly identified the absence of osseous involvement in 87 out of 89 patients and the presence of bone metastasis in 19 out of 21 patients. Thus using PET there were two false-negative and two false-positive cases. PET and bone scanning had, respectively, an accuracy of 96% and 66% in the evaluation of osseous involvement in patients with NSCLC. In conclusion, our data suggest that whole-body FDG PET may be useful in detecting bone metastases in patients with known NSCLC. [less ▲]

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