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Peer Reviewed
See detailPhotocatalytic TiO2 Macroscopic Fibers Obtained Through Integrative Chemistry
Kinadjian, Natacha ULg; Le Bechec, Mickael; Pigot, Thierry et al

Poster (2012, November 25)

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst ... [more ▼]

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst. Most studies to date show that reducing the particle size down to the nanoscale increases photocatalytic efficiency, as a result of a higher surface to volume ratio and because a larger proportion of the material is actually irradiated by light. We demonstrate that a multiscale shape design, which integrates surface roughness, particle shape, and 1D material processing and orientation, can favor photocatalytic properties in the solidgas regime, especially mineralization (conversion into CO2), when the hierarchical 1D orientation of the material is combined with unidirectional gas flow. Several materials with hierarchical structure were prepared and characterized. They have been tested for the photocatalytic mineralization of gaseous acetone and compared with commercial catalysts. Our study reveals that a suitable combination of multiscale design and optimization of the material orientation and gas flow favors high mineralization. [less ▲]

Detailed reference viewed: 5 (3 ULg)
Peer Reviewed
See detailPhotocatalytic TiO2 Macroscopic Fibers Obtained Through Integrative Chemistry
Kinadjian, Natacha ULg; Le Bechec, Mickael; Pigot, Thierry et al

Poster (2013, March)

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst ... [more ▼]

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst. Most studies to date show that reducing the particle size down to the nanoscale increases photocatalytic efficiency, as a result of a higher surface to volume ratio and because a larger proportion of the material is actually irradiated by light. We demonstrate that a multiscale shape design, which integrates surface roughness, particle shape, and 1D material processing and orientation, can favor photocatalytic properties in the solidgas regime, especially mineralization (conversion into CO2), when the hierarchical 1D orientation of the material is combined with unidirectional gas flow. Several materials with hierarchical structure were prepared and characterized. They have been tested for the photocatalytic mineralization of gaseous acetone and compared with commercial catalysts. Our study reveals that a suitable combination of multiscale design and optimization of the material orientation and gas flow favors high mineralization. [less ▲]

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Peer Reviewed
See detailPhotocatalytic TiO2 Macroscopic Fibers Obtained Through Integrative Chemistry
Kinadjian, Natacha ULg; Le Bechec, Mickael; Pigot, Thierry et al

in European Journal of Inorganic Chemistry [=EurJIC] (2012)

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst ... [more ▼]

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst. Most studies to date show that reducing the particle size down to the nanoscale increases photocatalytic efficiency, as a result of a higher surface to volume ratio and because a larger proportion of the material is actually irradiated by light. We demonstrate that a multiscale shape design, which integrates surface roughness, particle shape, and 1D material processing and orientation, can favor photocatalytic properties in the solidgas regime, especially mineralization (conversion into CO2), when the hierarchical 1D orientation of the material is combined with unidirectional gas flow. Several materials with hierarchical structure were prepared and characterized. They have been tested for the photocatalytic mineralization of gaseous acetone and compared with commercial catalysts. Our study reveals that a suitable combination of multiscale design and optimization of the material orientation and gas flow favors high mineralization. [less ▲]

Detailed reference viewed: 7 (2 ULg)
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Peer Reviewed
See detailPhotochemical properties and activity of water-soluble polymer/C60 nanohybrids for photodynamic therapy
Hurtgen, Marie ULg; Debuigne, Antoine ULg; Hoebeke, Maryse ULg et al

in Macromolecular Bioscience (2013), 13(1), 106-115

Water-soluble star-like poly(vinyl alcohol)/C60 and poly{[poly(ethylene glycol) acrylate]-co- (vinyl acetate)}/C60 nanohybrids are prepared by grafting macroradicals onto C60 and are assessed as ... [more ▼]

Water-soluble star-like poly(vinyl alcohol)/C60 and poly{[poly(ethylene glycol) acrylate]-co- (vinyl acetate)}/C60 nanohybrids are prepared by grafting macroradicals onto C60 and are assessed as photosensitizers for photodynamic therapy. The photophysical and biological properties of both nanohybrids highlight key characteristics influencing their overall efficiency. The macromolecular structure (linear/graft) and nature (presence/absence of hydroxyl groups) of the polymeric arms respectively impact the photodynamic activity and the stealthiness of the nanohybrids. The advantages of both nanohybrids are encountered in a third one, poly[(Nvinylpyrrolidone)- co-(vinyl acetate)]/C60, which has linear grafts without hydroxyl groups, and shows a better photodynamic activity. [less ▲]

Detailed reference viewed: 28 (6 ULg)
Peer Reviewed
See detailPhotochemical reactions of Rose Bengal as a probe of bile salts aggregation process
Seret, Alain ULg; Van de Vorst, Albert

Poster (1992, July)

Detailed reference viewed: 31 (0 ULg)
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Peer Reviewed
See detailPhotochemistry of 2,6-diisopropylphenol (propofol)
Heyne, B.; Tfibel, F.; Hoebeke, Maryse ULg et al

in Photochemical & Photobiological Sciences (2006), 5(11), 1059-1067

The photochemistry of the anaesthetic agent propofol (PPF) was investigated in three different solvents of quite different polarity (cyclohexane, methanol and phosphate buffer pH 7) by means of nanosecond ... [more ▼]

The photochemistry of the anaesthetic agent propofol (PPF) was investigated in three different solvents of quite different polarity (cyclohexane, methanol and phosphate buffer pH 7) by means of nanosecond laser flash photolysis and absorption spectroscopy. GC-MS spectrometry measurements of PPF in cyclohexane have revealed the formation of two major products upon low intensity UV continuous irradiation of PPF in aerated solution: the diphenol derivative of PPF and 2,6-diisopropyl-p-benzoquinone (PPFQ). Only the diphenol compound was obtained in anaerobic solution. PPF phenoxyl radical (PPF ) generation has been assigned as the original step leading to the formation of both the diphenol compound and PPFQ in cyclohexane as revealed by laser flash photolysis at 266 nm and by electron paramagnetic resonance spectroscopy as well. Investigation of PPF by nanosecond flash photolysis at 266 nm in the other solvents revealed the occurrence of different photochemical processes depending on the nature and the polarity of the solvent. A reaction scheme is proposed in order to discuss the mechanism of reaction of PPF in all media. [less ▲]

Detailed reference viewed: 23 (5 ULg)
Peer Reviewed
See detailThe photochemistry of the semi-oxidized form of Eosin Y and Rose Bengal in aqueous sodium dodecyl sulphate solutions
Seret, Alain ULg; Van de Vorst, Albert

in Journal of Photochemistry and Photobiology A : Chemistry (1988), 43(2), 193-206

In aerobic aqueous solutions, the semi-oxidized form of the halofluorescein dyes disappears via a bimolecular reaction with itself and via the formation of an adduct with OH− ions. In aerobic aqueous ... [more ▼]

In aerobic aqueous solutions, the semi-oxidized form of the halofluorescein dyes disappears via a bimolecular reaction with itself and via the formation of an adduct with OH− ions. In aerobic aqueous solutions of sodium dodecylsulphate, semi-oxidized rose bengal is solubilized in the micelles, and its exit rate from the micellar aggregates is lower than 60 s−1. The properties of semi-oxidized eosin Y in sodium dodecylsulphate solutions are interpreted in terms of a model based on an adsorption equilibrium between water-bound and micelle-bound dye radicals. This equilibrium depends on the surfactant concentration between the critical micelle concentration and 80 mmol dm−3. Over this range, the reactivity of the semi-oxidized form with itself and towards hydrophilic quenchers decreases when the surfactant concentration is increased. The reaction of the semi-oxidized form with itself is involved in the bleaching of these dyes and the photoproduct is clearly able to react with the semi-oxidized radical of the xanthene dyes. [less ▲]

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Peer Reviewed
See detailPhotoclick chemistry: Applications to 18F radiotracers preparation
Thonon, David ULg; Goukens, Eve ULg; Kaisin, Geoffroy ULg et al

in Journal of Labelled Compounds and Radiopharmaceuticals (2011)

Detailed reference viewed: 61 (21 ULg)
Peer Reviewed
See detailPhotodegradation of bacteria on TiO2 thin films produced by sol-gel method
Tasseroul, Ludivine ULg; Braconnier, Benoît; Nonet, Stéphane et al

Conference (2008)

Detailed reference viewed: 12 (3 ULg)
See detailPhotodegradation of bacteria with TiO2 produced by sol-gel method
Tasseroul, Ludivine ULg; Pàez Martinez, Carlos ULg; Braconnier, Benoît et al

Poster (2007)

Detailed reference viewed: 8 (3 ULg)
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Peer Reviewed
See detailPhotodegradation of phenol and benzoic acid by sol-gel-synthesized alkali metal-doped ZnO
Benhebal, H.; Chaib, M.; Léonard, Angélique ULg et al

in Materials Science in Semiconductor Processing (2012), 15(3), 264269

Detailed reference viewed: 42 (8 ULg)
See detailPhotodetachment and Photodissociation Mass Spectrometry of Biomolecule Ions
Gabelica, Valérie ULg

Conference (2007, April 27)

We recently explored the effects of irradiating DNA polyanions stored in a quadrupole ion trap (QIT) mass spectrometer with an optical parametric oscillator (OPO) laser between 250 nm and 285 nm. We ... [more ▼]

We recently explored the effects of irradiating DNA polyanions stored in a quadrupole ion trap (QIT) mass spectrometer with an optical parametric oscillator (OPO) laser between 250 nm and 285 nm. We studied DNA 6-mer to 20-mer single strands, and 12-base pair double strands. In all cases, laser irradiation causes electron detachment from the multiply charged DNA anions. Electron photo-detachment efficiency directly depends on the number of guanines in the strand, and maximum efficiency is observed between 260 and 275 nm. Collisional activation of the radical anions results in extensive fragmentation, which can be used to sequence the DNA strands. It has therefore important potential applications in analytical chemistry. We also obtained preliminary results on laser irradiation of DNA coupled to other chromophores (covalently bound or noncovalently bound). Depending on the chromophore, three different behaviors are encountered: (1) the photon energy can be redistributed in the molecule by internal conversion, (2) electron photodetachment was observed for a few chromophores, and (3) specific photodissociation was observed for a porphyrin chromophore. Here we will address the question of the mechanism of electron photodetachment. DNA multiply charged anions undergo one-photon electron ejection (oxidation) when subjected to laser irradiation at 260 nm (4.77 eV). Electron photodetachment is likely a fast process, given that photodetachment is able to compete with internal conversion and/or radiative relaxation to the ground state. The DNA [6-mer]3- ions studied here show a marked sequence-dependence of electron photodetachment yield. Remarkably, the photodetachment yield (dG6 > dA6 > dC6 > dT6) is inversely correlated with the base ionization potentials (G < A < C < T). Sequences with guanine runs show increased photodetachment yield as the number of guanine increases, in line with the fact that positive holes are the most stable in guanine runs. This correlation between photodetachment yield and the stability of the base radical may be explained by tunneling of the electron through the repulsive Coulomb barrier. The wavelength-dependence of electron detachment yield was studied for dG63-. Maximum electron photodetachment is observed in the wavelength range corresponding to base absorption (260-270 nm). This demonstrates the feasibility of gas-phase UV spectroscopy on large DNA anions. The calculations and the wavelength dependence suggest that the electron photodetachment is initiated at the bases and not at the phosphates. This also indicates that, although direct photodetachment could also occur, autodetachment from excited states, presumably corresponding to base excitation, is the dominant process at 260 nm. Excited states dynamics of large DNA strands still remains largely unexplored, and photo-oxidation studies on trapped DNA multiply charged anions can help bridging the gap between gas-phase studies on isolated bases or base pairs and solution-phase studies on full DNA strands. Time-resolved measurements on photodetachment and photodissociation can be used to contribute elucidating the mechanisms at stake in these novel experiments. [less ▲]

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See detailPhotodetachment and photodissociation mass spectrometry of DNA multiply charged ions
Gabelica, Valérie ULg; Rosu, Frédéric ULg; De Pauw, Edwin ULg et al

in Beck, Rainer D.; Drabbels, Marcel; Rizzo, Thomas R. (Eds.) Contributions 16th Symposium on Atomic and Surface Physics and Related Topics (2008)

Detailed reference viewed: 40 (1 ULg)
See detailPhotodetection Signals for Controlling Combustion
Parada, Luis; Ngendakumana, Philippe ULg

Report (2006)

Detailed reference viewed: 11 (0 ULg)
See detailA Photodiode for Combustion Control (1)
Tartari, Paula; Ngendakumana, Philippe ULg

Report (2003)

Detailed reference viewed: 6 (1 ULg)
See detailPhotodiodes for Combustion Control (V2)
Tartari, Paula; Ngendakumana, Philippe ULg

Report (2003)

Detailed reference viewed: 1 (0 ULg)
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Peer Reviewed
See detailPhotodissociation and radiative association ofHeH+ in the metastable triplet state
Loreau, Jerôme; Vranckx, Stéphane; Desouter-Lecomte, Michèle ULg et al

in Journal of Physical Chemistry A (2013), 117

Detailed reference viewed: 9 (1 ULg)
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Peer Reviewed
See detailPhotodissociation of the HeH+ ion into excited fragments (n=2,3) by time-dependent methods
Sodoga, K.; Loreau, J.; Lauvergnat, D. et al

in Physical Review. A (2009), 2009(80), 033417

Detailed reference viewed: 14 (3 ULg)
See detailPhotodissociation spectroscopy of cationic porphyrins in the gas phase. Influence of the complexation with DNA. Comparison with solution phase
Rosu, Frédéric ULg; De Pauw, Edwin ULg; Gabelica, Valérie ULg et al

in Beck, Rainer D.; Drabbels, Marcel; Rizzo, Thomas R. (Eds.) Contributions 16th Symposium on Atomic and Surface Physics and Related Topics (2008)

Detailed reference viewed: 21 (0 ULg)
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Peer Reviewed
See detailPhotodynamic therapy and imiquimod immunotherapy for basal cell carcinomas
Nikkels, Arjen ULg; Pierard-Franchimont, Claudine ULg; Tassoudji, Nazli ULg et al

in Acta Clinica Belgica (2005), 60(5, Sep-Oct), 227-234

Photodynamic therapy (PDT) and topical imiquimod immunotherapy (TII) are two recently introduced treatment modalities for certain types of basal cell carcinomas (BCC). We present a review of the relevant ... [more ▼]

Photodynamic therapy (PDT) and topical imiquimod immunotherapy (TII) are two recently introduced treatment modalities for certain types of basal cell carcinomas (BCC). We present a review of the relevant literature and report our own findings regarding the efficacy and tolerance of PDT and TII in the treatment of BCCs. According to published studies, the cure rates range from 75-95% for PDT and 42-100% for TII, depending on treatment modalities and BCC type. In our observations, 13 patients with nodular or superficial BCCs were treated by PDT using two courses of 3-hour topical application of methyl aminolevulinate, followed by 8 minutes illumination (lambda = 634 rim, e = 37J/cm(2)). Biopsies were taken before and one month after PDT. Side effects including pain and crusting were assessed. Eight patients with superficial BCC were treated by TII using 3 monthly courses each consisting of 3 weekly applications for 3 weeks followed by one week out of treatment. Biopsies were taken before and after 3 months of TII. Adverse reactions including erythema, oozing, ulceration, and crusting were recorded. Clinico-histological cure was obtained in 12/13 PDT cases as assessed after I month, and in 6/8 TII cases after 3 months. Minimal pain during illumination and crust formation were observed in 7/13 and 3/13 PDT cases, respectively. Variable erythema, oozing, ulceration, and crusting were observed in all TII-treated lesions. It is concluded that PDT represents an active and well tolerated alternative treatment for both nodular and superficial BCCs. TII also shows activity, although the tolerance may be poor and cure needs a longer time to be obtained. The final cosmetic appearance was fine following both PDT and TII procedures. Both PDT and TII may leave intact neoplastic aggregates inside the skin. They cannot be clinically perceived, leading to unexpected recurrences. It is stressed that the currently available efficacy information about PDT and TII deals with short term follow-up periods. A 5-year follow-up must be awaited before drawing firm conclusions. [less ▲]

Detailed reference viewed: 41 (3 ULg)