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See detailExit-channel dynamics in barrierless unimolecular reactions: Criteria of vibrational adiabaticity
Pavlov-Verevkin, Victor B.; Lorquet, Jean-Claude ULiege

in Journal of Chemical Physics (2005), 123(7), 074324

Conversion of translational into vibrational energy during the last step of a unimolecular reaction is brought about by the curvature of the reaction path. The corresponding coupling is analyzed by an ... [more ▼]

Conversion of translational into vibrational energy during the last step of a unimolecular reaction is brought about by the curvature of the reaction path. The corresponding coupling is analyzed by an angle-action reaction path Hamiltonian (RPH). The accuracy of the vibrational adiabatic approximation is found to be completely independent of the shape of the potential energy V(s). Vibrations are adiabatic when two independent dimensionless parameters are small. The first one, denoted as sigma, controls the dynamic coupling. The physical significance of the condition sigma << 1 is that the amplitude of the vibrations normal to the reaction path should be much smaller than the radius of curvature of the reaction path. The second parameter, denoted as mu, governs the static coupling. It results from the dependence of the vibrational frequency omega on the reaction coordinate s. The higher omega, the lower its derivative with respect to s and, more unexpectedly, the higher the translational energy epsilon, the lower mu is. A criterion for locating a particular dividing surface in barrierless reactions is proposed. This surface separates two regions of space: one where energy flows freely, and one where energy conversion between translation and vibration is hindered by adiabatic invariance. The nature of the dynamical constraint that prevents the product translational energy distribution from being fully statistical can be identified by a maximum entropy analysis. The constraint is found to bear on the translational momentum p(s), i.e., on the square root of the translational energy epsilon(1/2). This can be understood by applying Jacobi's form of the least action principle to the vibrationally adiabatic RPH. (c) 2005 American Institute of Physics. [less ▲]

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See detailExo-zodi Modeling for the Large Binocular Telescope Interferometer
Kennedy, Grant M.; Wyatt, Mark C.; Bailey, Vanessa et al

in The Astrophysical Journal Supplement Series (2015), 216

Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders ... [more ▼]

Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders of magnitude above the level of the solar system's zodiacal cloud, so characterization of the brightness distribution of exo-zodi down to much fainter levels is needed. To this end, the Large Binocular Telescope Interferometer (LBTI) will detect thermal emission from habitable zone exo-zodi a few times brighter than solar system levels. Here we present a modeling framework for interpreting LBTI observations, which yields dust levels from detections and upper limits that are then converted into predictions and upper limits for the scattered light surface brightness. We apply this model to the HOSTS survey sample of nearby stars; assuming a null depth uncertainty of 10[SUP]-4[/SUP] the LBTI will be sensitive to dust a few times above the solar system level around Sun-like stars, and to even lower dust levels for more massive stars. [less ▲]

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See detailExobiologie et complexité
Javaux, Emmanuelle ULiege; Nazé, Yaël ULiege

Article for general public (2005)

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See detailExobiology and Mars
Javaux, Emmanuelle ULiege

Scientific conference (2005)

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See detailExocellular and membrane-bound transpeptidases in Streptomyces
Dusart, Jean; Marquet, A.; Ghuysen, Jean-Marie ULiege

in 1st International Congress for Bacteriology, Jerusalem, 2-7 September, 1973. Abstracts. Vol. II. Free papers. (1973)

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See detailThe exocellular DD-carboxypeptidase of Streptomyces albus G: A metallo (Zn2+) enzyme
Dideberg, O.; Joris, Bernard ULiege; Frère, Jean-Marie ULiege et al

in FEBS Letters (1980), 117(1-2), 215-218

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See detailThe exocellular DD-carboxypeptidase-endopeptidase from Streptomyces albus Gl. Purification and chemical properties
Duez, Colette ULiege; Frère, Jean-Marie ULiege; Geurts, Francine et al

in Biochemical Journal (1978), 175(3), 793-800

The exocellular DD-carboxypeptidase-endopeptidase of Streptomyces albus G was purified to protein homogeneity and compared with the exocellular DD-carboxypeptidases-transpeptidases of Streptomyces R61 and ... [more ▼]

The exocellular DD-carboxypeptidase-endopeptidase of Streptomyces albus G was purified to protein homogeneity and compared with the exocellular DD-carboxypeptidases-transpeptidases of Streptomyces R61 and Actinomadura R39. The S. albus G enzyme, as it is isolated, occurs in two forms. Enzyme I (30% of the total amount) and enzyme II (70% of the total amount) are identical in all respects, except that, by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate, enzyme I has an apparent mol. wt. (9000) that is half of that found by molecular-sieve filtration under non-denaturing conditions. Irrespective of the technique used, enzyme II has an apparent mol. wt. of about 18500. [less ▲]

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See detailThe exocellular DD-carboxypeptidase-endopeptidase of Streptomyces albus G. Interaction with beta-lactam antibiotics.
Frère, Jean-Marie ULiege; Geurts, Francine; Ghuysen, Jean-Marie ULiege

in Biochemical Journal (1978), 175(3), 801-805

Kinetically, the three-step model proposed for the interaction between beta-lactam antibiotics and the exocellular DD-carboxypeptidases-transpeptidases of Streptomyces R61 and Actinomadura R39 [Frère ... [more ▼]

Kinetically, the three-step model proposed for the interaction between beta-lactam antibiotics and the exocellular DD-carboxypeptidases-transpeptidases of Streptomyces R61 and Actinomadura R39 [Frère, Ghuysen & Iwatsubo (1975) Eur. J. Biochem. 57, 343--357; Fuad, Frère, Ghuysen, Duez & Iwatsubo (1976) Biochem. J. 155, 623--629] applies to the interaction between the much less penicillin-sensitive exocellular DD-carboxypeptidase-endopeptidase of Streptomyces albus G and at least phenoxymethylpenicillin, cephalothin and cephalosporin C. The penicillin resistance of the albus G enzyme is mainly due to the low efficiency with which the first reversible complex formed with the antibiotic (complex EI) undergoes transformation into a second more stable complex EI*. Analysis of the ternary interaction between enzyme, NalphaNepsilon-diacetyl-L-lysyl-D-alanyl-D-alanine (Ac2-L-Lys-D-Ala-D-Ala) and cephalosporin C indicates a non-competitive mechanism. [less ▲]

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See detailThe exocellular β-lactamase of Streptomyces albus G. Purification, properties and comparison with the exocellular DD-carboxypeptidase
Duez, Colette ULiege; Frère, Jean-Marie ULiege; Klein, Daniel et al

in Biochemical Journal (1981), 193(1), 75-82

The exocellular β-lactamase of Streptomyces albus G has been purified to near protein homogeneity. It consists of one single polypeptide chain of mol.wt. 30 000-31 000, has a rather low isoelectric point ... [more ▼]

The exocellular β-lactamase of Streptomyces albus G has been purified to near protein homogeneity. It consists of one single polypeptide chain of mol.wt. 30 000-31 000, has a rather low isoelectric point (at pH 6.0) and contains less lysine (2.1%) and more half-cystine residues than most β-lactamases from other Gram-positive bacteria. Penicillins are much better substrates than ∆3-cephalosporins; the catalytic-centre activity of good penicillin substrates is 333-500s-1. The exocellular, mol.wt. 17000 DD-carboxypeptidase of S. albus G [previously purified to protein homogeneity; Duez, Frère, Geurts, Ghuysen, Dierickx & Delcambe (1978) Biochem. J. 175, 793-800] behaves as an exceedingly poor β-lactamase, hydrolysing benzylpenicillin into benzylpenicilloate 5 × 10-6-fold less rapidly than does the exocellular β-lactamase. To all appearances, the β-lactamase has no bivalent cation requirement whereas, as shown elsewhere [Dideberg, Charlier, Dupont, Vermeire, Frère & Ghuysen (1980) FEBS Lett. 117, 212-214, and Dideberg, Joris, Frère, Ghuysen, Weber, Robaye, Delbrouck & Roelands (1980) FEBS Lett. 117, 215-218], the DD-carboxypeptidase possesses one essential Zn2+ ion per molecule. Peptide 'mapping' and immunological studies suggest that the two Streptomyces enzymes probably have very different structural and mechanistic properties. [less ▲]

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See detailExocellular β-lactamases of Streptomyces albus G and strains R39 and K11
Johnson, Kenneth; Dusart, Jean; Campbell, James N. et al

in Antimicrobial Agents and Chemotherapy (1973), 3(2), 289-298

The beta-lactamases excreted by the highly benzylpenicillin-susceptible Streptomyces strain R39 and the highly benzylpenicillin-resistant Streptomyces albus G were isolated and purified. Neither beta ... [more ▼]

The beta-lactamases excreted by the highly benzylpenicillin-susceptible Streptomyces strain R39 and the highly benzylpenicillin-resistant Streptomyces albus G were isolated and purified. Neither beta-lactamase exhibited dd-carboxypeptidase activity. Both were anionic at pH 8.3, did not require metal ions, and were not sensitive to iodine, but were inhibited by Cu(2+) and readily inactivated by heat. p-Chloromercuribenzoate, iodoacetate, p-aminobenzoate, and substrates and inhibitors of dd-carboxypeptidase had no effect on beta-lactamase activity. The K(m) and V(max) values for beta-lactamase activity were studied with 6-aminopenicillanic acid and with various penicillins and cephalosporins. The beta-lactamase from the related strain K11 of Streptomyces, which is intermediate in its susceptibility to benzylpenicillin, was partially purified, and its activity was compared on the various substrates. [less ▲]

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See detailExocomet signatures around the A-shell star φ Leonis?
Eiroa, C.; Rebollido, I.; Montesinos, B. et al

in Astronomy and Astrophysics (2016), 594

We present an intensive monitoring of high-resolution spectra of the Ca ii K line in the A7IV shell star φ Leo at very short (minutes, hours), short (night to night), and medium (weeks, months) timescales ... [more ▼]

We present an intensive monitoring of high-resolution spectra of the Ca ii K line in the A7IV shell star φ Leo at very short (minutes, hours), short (night to night), and medium (weeks, months) timescales. The spectra show remarkable variable absorptions on timescales of hours, days, and months. The characteristics of these sporadic events are very similar to most that are observed toward the debris disk host star β Pic, which are commonly interpreted as signs of the evaporation of solid, comet-like bodies grazing or falling onto the star. Therefore, our results suggest the presence of solid bodies around φ Leo. To our knowledge, with the exception of β Pic, our monitoring has the best time resolution at the mentioned timescales for a star with events attributed to exocomets. Assuming the cometary scenario and considering the timescales of our monitoring, our results indicate that φ Leo presents the richest environment with comet-like events known to date, second only to β Pic. [less ▲]

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See detailExogenous glucose oxidation during exercise in relation to the power output.
Pirnay, Freddy ULiege; Scheen, André ULiege; Gautier, J. F. et al

in International Journal of Sports Medicine (1995), 16(7), 456-60

In order to study the influence of the power output on the oxidation rate of exogenous glucose and on the contribution of the various substrates to the energy demand, we combined the use of artificially ... [more ▼]

In order to study the influence of the power output on the oxidation rate of exogenous glucose and on the contribution of the various substrates to the energy demand, we combined the use of artificially enriched 13C-glucose with classical indirect calorimetry during uphill treadmill exercise. Six young male healthy subjects underwent three exercise bouts, in a randomized order and at least two weeks apart, at a low (45% VO2max, 1822 +/- 194 ml O2/min for 4 hours), moderate (60% VO2max, 2582 +/- 226 ml O2/min for 3 hours), and high intensity (75% VO2max, 3036 +/- 287 ml O2/min for 2 hours). After 10 min of exercise, each subject ingested 100 g of artificially 13C-labelled glucose dissolved in 400 ml of water. Over the four hours of the exercise at 45% VO2max, the amount of exogenous glucose oxidized was 89.5 +/- 5.9 g from the 100 g ingested. In all exercise bouts, the oxidation of exogenous glucose already began during the first 30 min after ingestion and peaked at 120 min. The maximum oxidation rates averaged 0.64 +/- 0.07, 0.75 +/- 0.04, and 0.63 +/- 0.08 g/min, and the mean amounts of exogenous glucose oxidized over the first two hours averaged 51.7 +/- 8.0, 61.5 +/- 6.6 and 50.9 +/- 8.45 g, at 45, 60 and 75% VO2max respectively. The contribution of the oxidation of exogenous glucose to the total energy supply progressively decreased when the power output increased, from 19.6 to 12.2%. In the meantime, the contribution of total carbohydrates (exogenous+endogenous) progressively increased from 55.1 to 77.8% while the contribution of lipids decreased from 35.5 to 16.6%. In conclusion, exogenous glucose ingested during exercise is largely oxidized and strongly contributes to the energy supply. The oxidation rate first increases with the power output, but levels off or even decreases at high intensity exercise. [less ▲]

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See detailExogenous prostaglandin administration and pseudo-bartter syndrome
Langhendries, JP; Thiry, V; Bodart, E et al

in European Journal of Pediatrics (1989), 149

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See detailDie exokrine Pankreasfunktion beim kranken Pferd
Sandersen, Charlotte ULiege; Serteyn, Didier ULiege; Grulke, Sigrid ULiege

in Vervuert; Achenbach; Gäbel (Eds.) et al LBH, Proccedings 5. Leipziger Tieraerzte Tag (2009)

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See detail"Exolysosomes", Enzyme-Containing Vesicles in the Ecdysial Space of Molting Crabs
Compère, Philippe ULiege; Bouchtia, Hicham; Thiry, Marc ULiege et al

in Journal of Structural Biology (1997), 119(3), 247-59

Free vesicle-like bodies (VLBs) present in the ecdysial space of cuticle regions undergoing degradation during preecdysis of the Atlantic shore crab Carcinus maenas have been interpreted either as ... [more ▼]

Free vesicle-like bodies (VLBs) present in the ecdysial space of cuticle regions undergoing degradation during preecdysis of the Atlantic shore crab Carcinus maenas have been interpreted either as infectious organisms or as secretion structures associated with degradation of the old cuticle. Ultrastructural, cytochemical, and immunocytological investigations were performed to test these hypotheses and to see whether VLBs are peculiar to this crab species. Similar VLBs were systematically found in two other preecdysial crabs, Cancer pagurus and Macropipus puber. In Car, maenas, they originate during early premolt inside Golgi buddings and are often gathered into large vacuoles in epidermal cells. The histochemical azo-dye technique and a cerium-based cytochemical method revealed acid phosphatase activity in both the ecdysial space and the VLBs, while Feulgen's method and immunocytological labeling always failed to reveal any DNA or RNA in either the ecdysial space or the VLBs. We conclude that VLBs are not infectious organisms but "extracellular" cuticle-degrading organelles of lysosomal origin and propose to coin them "exolysosomes." [less ▲]

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See detailExoMars : L’Europe en route vers Mars !
Stiepen, Arnaud ULiege

Article for general public (2016)

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See detailExome copy number variation detection: Use of a pool of unrelated healthy tissue as reference sample
Wenric, Stéphane ULiege; Sticca, Tiberio ULiege; CABERG, Jean-Hubert ULiege et al

in Genetic Epidemiology (2017)

An increasing number of bioinformatic tools designed to detect CNVs (copy number variants) in tumor samples based on paired exome data where a matched healthy tissue constitutes the reference have been ... [more ▼]

An increasing number of bioinformatic tools designed to detect CNVs (copy number variants) in tumor samples based on paired exome data where a matched healthy tissue constitutes the reference have been published in the recent years. The idea of using a pool of unrelated healthy DNA as reference has previously been formulated but not thoroughly validated. As of today, the gold standard for CNV calling is still aCGH but there is an increasing interest in detecting CNVs by exome sequencing. We propose to design a metric allowing the comparison of two CNV profiles, independently of the technique used and assessed the validity of using a pool of unrelated healthy DNA instead of a matched healthy tissue as reference in exome-based CNV detection. We compared the CNV profiles obtained with three different approaches (aCGH, exome sequencing with a matched healthy tissue as reference, exome sequencing with a pool of eight unrelated healthy tissue as reference) on three multiple myeloma samples. We show that the usual analyses performed to compare CNV profiles (deletion/amplification ratios and CNV size distribution) lack in precision when confronted with low LRR values, as they only consider the binary status of each CNV. We show that the metric-based distance constitutes a more accurate comparison of two CNV profiles. Based on these analyses, we conclude that a reliable picture of CNV alterations in multiple myeloma samples can be obtained from whole-exome sequencing in the absence of a matched healthy sample. [less ▲]

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See detailExome sequencing in Brown-Vialetto-van Laere syndrome.
Johnson, Janel O; Gibbs, J Raphael; Van Maldergem, Lionel ULiege et al

in American Journal of Human Genetics (2010), 87(4), 567-9569-70

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See detailExome sequencing of tumors: relevance in copy-number alteration (CNA) analysis and fixed tissue samples.
Wenric, Stéphane ULiege; JOSSE, Claire ULiege; Fasquelle, Corinne ULiege et al

Poster (2013, March 15)

Genomic DNA has been extracted from both cryopreserved and formalin-fixed paraffin-embedded forms of 2 different tumor samples (triple negative, and Her2+). Exome sequencing has been performed on all 4 ... [more ▼]

Genomic DNA has been extracted from both cryopreserved and formalin-fixed paraffin-embedded forms of 2 different tumor samples (triple negative, and Her2+). Exome sequencing has been performed on all 4 forms, as well as SNP and CNA detection. A comparison of the various metrics and results related to the sequencing, mapping, and variants detection has been done, outlining what can, and can’t be done with exome data sequenced from cryopreserved and FFPE tissue. [less ▲]

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