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See detailPhotophysical investigation of Rose Bengal in aqueous sodium taurocholate solutions
Seret, Alain ULg; Van de Vorst, Albert

in Journal of Photochemistry and Photobiology B : Biology (1993), 17(1), 47-56

The photophysics of rose bengal has been studied in aqueous sodium taurocholate solutions with or without 0.6 mol NaCl dm−3. The ground and first excited singlet states solubilize only in the aggregates ... [more ▼]

The photophysics of rose bengal has been studied in aqueous sodium taurocholate solutions with or without 0.6 mol NaCl dm−3. The ground and first excited singlet states solubilize only in the aggregates formed by sodium taurocholate, whereas the first triplet state solubilizes both in the bulk phase and in the aggregates. A lower limit of the corresponding entry and exit rate constants ke and ks, respectively has been estimated: ke ≥ 5 X 106 dm3 mol−1 s−1 (2x107 dm3 mol−1 s−1 with 0.6 mol NaCl dm−3) and ks ≥ 105 s−1. The triplet state as well as the semioxidized radical react with the taurocholate anion. The former reaction leads to the formation of semireduced dye. The latter is responsible for the detection of only semioxidized radicals which move freely in the aqueous phase. The results are compared with those obtained previously in aqueous sodium dodecyl sulphate solutions and the possible biological implication is discussed. [less ▲]

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See detailPhotophysical properties of Eosin dianion in cationic micellar solutions
Seret, Alain ULg; Gandin, Ezio; Van de Vorst, Albert

in Archives Internationales de Physiologie et de Biochimie (1986, November), 94(4), 15

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See detailPhotophysique et couleur cutanée.
Pierard, Gérald ULg; Uhoda, Emmanuelle ULg

in Revue Médicale de Liège (2005), 60 Suppl 1

The optical properties of skin and of chromophores orientate and absorbe light. The resulting skin colour can be assessed by visual inspection or by objective methods. Spectrophotometry, tristimulus ... [more ▼]

The optical properties of skin and of chromophores orientate and absorbe light. The resulting skin colour can be assessed by visual inspection or by objective methods. Spectrophotometry, tristimulus colorimetry and computerized image analysis are well codified methods. Epidermal melanisation is detected with great sensitivity under ultraviolet light illumination. [less ▲]

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See detailPhotoprotection cutanée.
Henry, Frédérique ULg; Pierard, Claudine ULg; Pierard, Gérald ULg

in Revue Médicale de Liège (2005), 60 Suppl 1

Physical or chemical photoprotection is mandatory in order to prevent some of the negative effects of ultraviolet light exposure.

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See detailLa photoprotection en 2012
LIBON, Florence ULg; DEZFOULIAN, Bita ULg; NIKKELS, Arjen ULg

in Skin Inc (2012)

La photoprotection est essentielle dans la prévention du processus de photovieillissement et de la carcinogenèse cutanée. Elle peut être comportementale, naturelle, induite, vestimentaire, topique et ... [more ▼]

La photoprotection est essentielle dans la prévention du processus de photovieillissement et de la carcinogenèse cutanée. Elle peut être comportementale, naturelle, induite, vestimentaire, topique et systémique. La photoprotection vestimentaire inclut le port de vêtements protecteurs, de lunettes solaires et de chapeau. La photoprotection externe topique repose sur l'utilisation de différents véhicules contenant siot des filtres minéraux, ayant pour but une réflexion de la radiation ultraviolette incidente, soit des agents chimiques qui absorbent une partie de la radiation incidente. La photoprotection systémique consiste en l'administration, par voie orale, de substances photoprotectrices. D'autres nouvelles voies de photoprotection sont les stimulations chimique ou hormonale de la mélanogenèse. Cet article revoit les dernières évolutions dans ce domaine. [less ▲]

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See detailPHOTOREDUCTION OF PROTOCHLOROPHYLLIDE IN DARK-GROWN BEAN COTYLEDONS AS A FUNCTION OF AGE
SCHOEFS, B.; Bertrand, Marie-Christine ULg; Garnir, Henri-Pierre ULg et al

in Murata, N (Ed.) Research in Photosynthesis (1992)

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See detailPHOTOREDUCTION OF PROTOCHLOROPHYLLIDE TO CHLOROPHYLLIDE IN 2-D-OLD DARK-GROWN BEAN (PHASEOLUS-VULGARIS CV COMMODORE) LEAVES - COMPARISON WITH 10-D-OLD DARK-GROWN (ETIOLATED) LEAVES
SCHOEFS, B.; Franck, Fabrice ULg

in Journal of Experimental Botany (1993), 44(263), 1053-1057

Two-d-old leaves which do not contain prolamellar bodies synthesize active protochlorophyllide in darkness. When protochlorophyllide is photoreduced by one intense white flash, a main chlorophyllide ... [more ▼]

Two-d-old leaves which do not contain prolamellar bodies synthesize active protochlorophyllide in darkness. When protochlorophyllide is photoreduced by one intense white flash, a main chlorophyllide species emitting at 690 nm is formed. After the photoreduction, the emission maximum is shifted to 675 nm within 5 s. This result suggests that in young leaves, chlorophyllide formed after one flash is quickly released from the active site of NADPH: protochlorophyllide oxidoreductase. This interpretation is strenghtened by time-resolved fluorescence measurements at room temperature, showing that 675 nm emitting chlorophyllide does not transfer excitation energy to the 696 nm emitting chlorophyllide which is formed in very low amount. In 10-d-old bean leaves, the 690 nm chlorophyllide emitting species formed after one short flash undergoes the well-known rapid and Shibata spectral shifts. The 675 nm emitting chlorophyllide appears only as a shoulder. At both ages, the fluorescence intensity of the active protochlorophyllide strongly decreases during and after photoreduction, suggesting rapid modifications in the close environment of the pigment. [less ▲]

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See detailThe photorefractive effect at large modulation depth in semiconductors with multiple defect levels
Nguyen, Ngoc Duy ULg; Schmeits, Marcel ULg

in Applied Physics B : Lasers & Optics (2002), 74

The photorefractive effect in semiconducting mate- rials with multiple defects is studied in the case of modulation depth m = 1. The basic equations are Poisson's equation and the continuity equations for ... [more ▼]

The photorefractive effect in semiconducting mate- rials with multiple defects is studied in the case of modulation depth m = 1. The basic equations are Poisson's equation and the continuity equations for electrons, holes and occupied defect levels. They include all recombination and optical generation mechanisms between the defect levels and valence and conduc- tion bands. Their explicit numerical solution yields microscopic quantities such as space- and time-dependent electrical field profiles, carrier concentrations, as well as generation and re- combination rates. The fundamental Fourier component of the electric field yields the two-wave-mixing gain. Application is made for InP with two levels in the forbidden gap, for which steady-state and transient resulting quantities are shown. The re- sulting features at large modulation depth are of non-sinusoidal shape. Due to the complexity of the system, the final results strongly depend on all parameters intervening in the models used, as is illustrated for several typical cases. [less ▲]

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See detailPhotorefractive holographic interferometry for movable artwork assessment
Thizy, Cédric ULg; Georges, Marc ULg; Koulompi, Eleni et al

in Hesselink, Lambertus; Feinberg, Jack (Eds.) Controlling Light with Light: Photorefractive Effects, Photosensitivity, Fiber Gratings, Photonic Materials and More (PR07) (2007, October)

Photorefractive holographic interferometry is applied to assessment of movable cultural heritage. Its role is to observe tiny signatures resulting from internal artwork characteristics. In the future, the ... [more ▼]

Photorefractive holographic interferometry is applied to assessment of movable cultural heritage. Its role is to observe tiny signatures resulting from internal artwork characteristics. In the future, the system will be used for both antifraud and restoration [less ▲]

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See detailPhotorefractive ZnTe grown by traveling heater method
Verstraeten, David; Launay, Jean-Claude; Delaye, Philippe et al

in Trends in Optics and Photonics (2003), 87

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See detailPhotos + annonce de Colloque International, U. Lg
Sacré, Robert ULg

in Soul Bag (1991), (124),

1) PHOTO DE COUVERTURE Johnny Heartman 2) Photos Ann PEEBLES , Otis CLAY , Lynn WHITE ; Hasselt Nov. 1989 3) Annonce de la Conférence Internationale de Septembre 1991 à l' Université de Liège ( The ... [more ▼]

1) PHOTO DE COUVERTURE Johnny Heartman 2) Photos Ann PEEBLES , Otis CLAY , Lynn WHITE ; Hasselt Nov. 1989 3) Annonce de la Conférence Internationale de Septembre 1991 à l' Université de Liège ( The secular in religious music and the sacred in secular music" [less ▲]

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See detailPhotosensitized generation of hydroxyl radical by eught new sulfur and selenium analogs of psoralen
Collet, A.; Hoebeke, Maryse ULg; Piette, J. et al

in Journal of Photochemistry and Photobiology B : Biology (1996), 35

comparative study by ESR of the hydroxyl radical generation by 8 eight new sulfur and selenium analogs of psoralen

Detailed reference viewed: 4 (2 ULg)
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See detailPhotosensitized Production of Singlet Oxygen by Merocyanine 540 Bound to Liposomes
Hoebeke, Maryse ULg; Piette, Jacques ULg; van de Vorst, A.

in Journal of Photochemistry and Photobiology B : Biology (1991), 9(3-4), 281-94

The production of singlet oxygen by merocyanine 540 was studied in dimyristoyl-phosphatidylcholine liposomes using two singlet oxygen probes: 9,10-anthracenedipropionic acid (water soluble) and 9,10 ... [more ▼]

The production of singlet oxygen by merocyanine 540 was studied in dimyristoyl-phosphatidylcholine liposomes using two singlet oxygen probes: 9,10-anthracenedipropionic acid (water soluble) and 9,10-dimethylanthracene (liposoluble). Upper and lower limits of singlet oxygen quantum yield for bound merocyanine 540 were determined to be 0.055 and 0.015 respectively. The diffusion characteristics of singlet oxygen were examined using the isotropic enhancement effect of D2O and the inhibitory effect of sodium azide. It was shown that 1O2 spent more than 87% of its lifetime in a vesicle environment. When the singlet-reacting substrate and the dye were both located in the bilayer, approximately 40% of the singlet oxygen remained in the liposomes where it was originally generated. [less ▲]

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See detailThe "photosphere-wind connection" in Wolf-Rayet stars: simultaneous photometry and spectroscopy of EZ CMa
Morel, Thierry ULg; St-Louis, N.; Marchenko, S. V.

in Liege International Astrophysical Colloquia (1996)

Not Available

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See detailPhotospheric abundance peculiarities in chromospherically active stars
Morel, Thierry ULg; Micela, G.; Favata, F.

in 13th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun (2005, March 01)

Not Available

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See detailPhotospheric Abundance Peculiarities in RS CVn Binaries
Morel, Thierry ULg; Micela, Giuseppina; Favata, Fabio

in Astrophysics & Space Science (2006), 304

We discuss the results of a LTE abundance study of 14 single-lined RS CVn binaries. Increasingly peculiar abundance ratios are observed for the cooler and more active stars in this sample (this is best ... [more ▼]

We discuss the results of a LTE abundance study of 14 single-lined RS CVn binaries. Increasingly peculiar abundance ratios are observed for the cooler and more active stars in this sample (this is best illustrated in the case of oxygen). This may arise from the existence of large spot groups, departures from LTE much larger than anticipated and/or inadequacies in the Kurucz model atmospheres for these objects. [less ▲]

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See detailThe photospheric abundances of active binaries. II. Atmospheric parameters and abundance patterns for 6 single-lined RS CVn systems
Morel, Thierry ULg; Micela, G.; Favata, F. et al

in Astronomy and Astrophysics (2003), 412

Photospheric parameters and abundances are presented for a sample of single-lined chromospherically active binaries from a differential LTE analysis of high-resolution spectra. Abundances have been ... [more ▼]

Photospheric parameters and abundances are presented for a sample of single-lined chromospherically active binaries from a differential LTE analysis of high-resolution spectra. Abundances have been derived for 13 chemical species, including several key elements such as Li, Mg, and Ca. Two methods have been used. The effective temperatures, surface gravities and microturbulent velocities were first derived from a fully self-consistent analysis of the spectra, whereby the temperature is determined from the excitation equilibrium of the Fe I lines. The second approach relies on temperatures derived from the (B-V) colour index. These two methods give broadly consistent results for the stars in our sample, suggesting that the neutral iron lines are formed under conditions close to LTE. We discuss the reliability in the context of chromospherically active stars of various colour indices used as temperature indicators, and conclude that the (V-R) and (V-I) colours are likely to be significantly affected by activity processes. Irrespective of the method used, our results indicate that the X-ray active binaries studied are not as metal poor as previously claimed, but are at most mildly iron-depleted relative to the Sun (-0.41protect <~ [Fe/H]protect la +0.11). A significant overabundance of several chemical species is observed (e.g., the alpha -synthezised elements). These abundance patterns are discussed in relation to stellar activity. Based on observations collected at ESO (La Silla, Chile). Table A.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/495 [less ▲]

Detailed reference viewed: 13 (2 ULg)