References of "1997"
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See detailPsychrophilic Enzymes: A Thermodynamic Challenge
Gerday, Charles ULg; Aittaleb, Mohamed; Arpigny, Jean Louis et al

in Biochimica et Biophysica Acta (1997), 1342(2), 119-31

Psychrophilic microorganisms, hosts of permanently cold habitats, produce enzymes which are adapted to work at low temperatures. When compared to their mesophilic counterparts, these enzymes display a ... [more ▼]

Psychrophilic microorganisms, hosts of permanently cold habitats, produce enzymes which are adapted to work at low temperatures. When compared to their mesophilic counterparts, these enzymes display a higher catalytic efficiency over a temperature range of roughly 0-30 degrees C and a high thermosensitivity. The molecular characteristics of cold enzymes originating from Antarctic bacteria have been approached through protein modelling and X-ray crystallography. The deduced three-dimensional structures of cold alpha-amylase, beta-lactamase, lipase and subtilisin have been compared to their mesophilic homologs. It appears that the molecular adaptation resides in a weakening of the intramolecular interactions, and in some cases in an increase of the interaction with the solvent, leading to more flexible molecular edifices capable of performing catalysis at a lower energy cost. [less ▲]

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See detailSite-Directed Mutagenesis of the Actinomadura R39 DD-Peptidase
Zhao, GuoHua; Duez, Colette ULg; Forceille, Christine et al

in Biochemical Journal (1997), 327(2), 377-381

The role of various residues in the conserved structural elements of the Actinomadura R39 penicillin-sensitive dd-peptidase has been studied by site-directed mutagenesis. Replacement of Ser-298 of the ... [more ▼]

The role of various residues in the conserved structural elements of the Actinomadura R39 penicillin-sensitive dd-peptidase has been studied by site-directed mutagenesis. Replacement of Ser-298 of the 'SDN loop' by Ala or Gly significantly decreased the kcat/Km value for the peptide substrate, but only by a factor of 15 and had little effect on the other catalytic properties. Mutations of Asn-300 of the same loop and of Lys-410 of the KTG triad yielded very unstable proteins. However, the N300S mutant could be purified as a fusion protein with thioredoxin that exhibited decreased rates of acylation by the peptide substrate and various cephalosporins. Similar fusion proteins obtained with the N300A, K410H and K410N mutants were unstable and their catalytic and penicillin-binding properties were very strongly affected. In transpeptidation reactions, the presence of the acceptor influenced the kcat/Km values, which suggested a catalytic pathway more complex than a simple partition of the acyl-enzyme between hydrolysis and aminolysis. These results are compared with those obtained with two other penicillin-sensitive enzymes, the Streptomyces R61 dd-peptidase and Escherichia coli penicillin-binding protein (PBP) 5. [less ▲]

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See detailLes vertus de la traduction
Bodson, Arthur ULg

Scientific conference (1997, October 11)

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See detailEglise et société moderne aux XIXe-XXe s.
Jadoulle, Jean-Louis ULg

Scientific conference (1997, October 10)

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See detailThe basic pattern of activation in motor and sensory temporal tasks: positron emission tomography data
Lejeune, Helga ULg; Maquet, Pierre ULg; Bonnet, Michel et al

in Neuroscience Letters (1997), 235(1-2), 21-24

Positron emission tomography (PET) data were obtained from subjects performing a synchronization task (target duration 2700 ms). A conjunction analysis was run to identify areas prominently activated both ... [more ▼]

Positron emission tomography (PET) data were obtained from subjects performing a synchronization task (target duration 2700 ms). A conjunction analysis was run to identify areas prominently activated both in this task and in a temporal generalization task (target duration 700 ms) used previously. The common pattern of activation included the right prefrontal, inferior parietal and anterior cingulate cortex, the left putamen and the left cerebellar hemisphere. These areas are assumed to play a major role in time processing, in relation to attention and memory mechanisms. [less ▲]

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See detailPinch Point Method in Optimization of Advanced Combined Cycles
Maréchal, François; Dumont, Marie-Noëlle ULg

Poster (1997, October 05)

The pinch point method has been developed to identify energy saving opportunities in industrial processes, The use of the composite curves allows to compute the minimum energy requirement of a process and ... [more ▼]

The pinch point method has been developed to identify energy saving opportunities in industrial processes, The use of the composite curves allows to compute the minimum energy requirement of a process and to determine optimal heat exchange between hot urd cold streams. The use of MILP (Mixed Integer Linear Programming) optimisation method allows to extend the approach to solve combined heat and power problems. The method is applied here to determine the optimal configuration of combined cycles, It allows to maximize the mechanical power production without having to consider the heat exchangersc onfiguration in the boiler nor in the preheating section. The method is also used to compute the steam extractions or productions and their optimal pressure levels that maximize the mechanical power produced From these results, the heat exchangers network structure is then determined. Three situations are analyzed: l) the heat recovery in a classical boiler using air preheating, 2) the gas turbine combined cycle and. 3) the " isothermal" gas turbine. The " isothermal" gas turbine is an innovative promising technology that uses a partial oxydation reactor followed by a staged combustion between the expansion stages to reach a quasi isothermal profile during the expansion. This allows to reduce the exergy losses in the gas turbine. The resulting flue gases are used in a combined cycle optimized with the method presented here. Diffirent configurations are discussed We show that the structure of combined cycles may strongly differ from one to another. [less ▲]

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See detailStereotactic radiation therapy for brain metastases: the Lausanne experience
Zouhair, Abderrahim; Tercier, Nicolas; Fankhauser, Heinz et al

in Bulletin du Cancer. Radiothérapie : Journal de la Société Française du Cancer : Organe de la Société Française de Radiothérapie Oncologique (1997)

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See detailIsolated systolic and diastolic dippers, an intermediate subgroup between dippers and non-dippers
Moonen, martial; Saint-Remy, Annie ULg; Krzesinski, Jean-Marie ULg et al

Conference (1997, October 04)

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See detailRelationships between left ventricular hypertrophy and the amplitude of the dipping
Saint-Remy, Annie ULg; moonen, martial; Krzesinski, Jean-Marie ULg et al

Conference (1997, October 04)

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See detailThe LMC transition star R 84 and the core of the LH 39 OB association.
Heydari-Malayeri, M.; Courbin, F.; Rauw, Grégor ULg et al

in Astronomy and Astrophysics (1997), 326

On the basis of sub-arcsecond imaging obtained at the ESO NTT with SUSI and the ESO ADONIS adaptive optics system at the 3.6m telescope, we resolve and study the core components of the LMC OB association ... [more ▼]

On the basis of sub-arcsecond imaging obtained at the ESO NTT with SUSI and the ESO ADONIS adaptive optics system at the 3.6m telescope, we resolve and study the core components of the LMC OB association LH 39. The central star of the association, the rare transition object R 84, is also investigated using CASPEC echelle spectroscopy at the ESO 3.6m telescope. A new, powerful image restoration code that conserves the fluxes allows us to obtain the magnitudes and colors of the components. We bring out some 30 stars in a ~16"x16" area centered on R 84. At a resolution of 0.19"(FWHM), the closest components to R 84 are shown to be stars #21 and #7 lying at 1.1"NW and 1.7"NW respectively of the transition star. The former is possibly a blue star of V=16.7mag and the latter with its V=17.5mag is the reddest star of the field, after R 84. Star #7 turns out to be too faint to correspond to the red M2 supergiant previously reported to contaminate the spectrum of R 84. If the late-type spectrum is due to a line-of-sight supergiant with a luminosity comparable to R 84, it should lie closer than 0.12" to R 84. The transition star shows spectral variability between 1982 and 1991. We also note some slight radial velocity variations of the Of emission lines over timescales of several years. Furthermore, we derive the spectral types of two of the brightest stars of the cluster, using long slit spectra obtained at the NTT telescope equipped with EMMI, and discuss the apparent absence of O type stars in this association. [less ▲]

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See detailEIT and LASCO Observations of the Initiation of a Coronal Mass Ejection
Dere, K. P.; Brueckner, G. E.; Howard, R. A. et al

in Solar Physics (1997), 175

We present the first observations of the initiation of a coronal mass ejection (CME) seen on the disk of the Sun. Observations with the EIT experiment on SOHO show that the CME began in a small volume and ... [more ▼]

We present the first observations of the initiation of a coronal mass ejection (CME) seen on the disk of the Sun. Observations with the EIT experiment on SOHO show that the CME began in a small volume and was initially associated with slow motions of prominence material and a small brightening at one end of the prominence. Shortly afterward, the prominence was accelerated to about 100 km s[SUP]-1[/SUP] and was preceded by a bright loop-like structure, which surrounded an emission void, that traveled out into the corona at a velocity of 200 400 km s[SUP]-1[/SUP]. These three components, the prominence, the dark void, and the bright loops are typical of CMEs when seen at distance in the corona and here are shown to be present at the earliest stages of the CME. The event was later observed to traverse the LASCO coronagraphs fields of view from 1.1 to 30 Ro. Of particular interest is the fact that this large-scale event, spanning as much as 70 deg in latitude, originated in a volume with dimensions of roughly 35" (2.5 x 10[SUP]4[/SUP] km). Further, a disturbance that propagated across the disk and a chain of activity near the limb may also be associated with this event as well as a considerable degree of activity near the west limb. [less ▲]

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See detailEnhancement of MSH2-MSH3-mediated mismatch repair recognition by the yeast MLH1-PMS1 complex
Habraken, Yvette ULg; Sung, Patrick; Prakash, Louise et al

in Current Biology (1997), 7(10), 790-3

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See detailEIT Observations of the Extreme Ultraviolet Sun
Moses, D.; Clette, Frédéric; Delaboudinière, J.-P. et al

in Solar Physics (1997), 175

The Extreme Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft has been operational since 2 January 1996. EIT observes the Sun over a 45 x 45 arc min field of view in four emission line ... [more ▼]

The Extreme Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft has been operational since 2 January 1996. EIT observes the Sun over a 45 x 45 arc min field of view in four emission line groups: Feix, x, Fexii, Fexv, and Heii. A post-launch determination of the instrument flatfield, the instrument scattering function, and the instrument aging were necessary for the reduction and analysis of the data. The observed structures and their evolution in each of the four EUV bandpasses are characteristic of the peak emission temperature of the line(s) chosen for that bandpass. Reports on the initial results of a variety of analysis projects demonstrate the range of investigations now underway: EIT provides new observations of the corona in the temperature range of 1 to 2 MK. Temperature studies of the large-scale coronal features extend previous coronagraph work with low-noise temperature maps. Temperatures of radial, extended, plume-like structures in both the polar coronal hole and in a low latitude decaying active region were found to be cooler than the surrounding material. Active region loops were investigated in detail and found to be isothermal for the low loops but hottest at the loop tops for the large loops. [less ▲]

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