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See detailSelf-organized criticality in phylogenetic-like tree growths
Vandewalle, Nicolas ULg; Ausloos, Marcel ULg

in Journal de Physique I (1995), 5(8), 1011-1025

A simple stochastic model of Darwinistic evolution generating phylogenetic-like trees is developed. The model is based on a branching process taking competition-correlation effects into account. In ... [more ▼]

A simple stochastic model of Darwinistic evolution generating phylogenetic-like trees is developed. The model is based on a branching process taking competition-correlation effects into account. In presence of finite and short range correlations, the process self-organizes into a critical steady-state in which intermittent bursts of activity of all sizes are generated. On a geological-like time scale, this behaviour agrees with punctuated equilibrium features of biological evolution. The simulated phylogenetic-like trees are found to be self-similar. The dynamics of the transient regimes show a power law decrease of the order parameter towards the 0(+) value which characterizes an unstable critical state. The genetic range k of competition-correlations between living species is found to be a relevant parameter which determines the universality class of the evolution process. An infinite competition-correlation range destroys however the self-organized critical behaviour. The fractal dimension D-f of the phylogenetic-like trees increases from 2.0 to infinity as k goes from 1 to infinity. The critical exponent tau of avalanche size-distribution decreases from about 3/2 (for k = 1) and reaches about 1.2 for k = 10. A hyperscaling relation seems to relate the various universality classes. Through a mean-field theory, we mention that the evolution process is much more complex than a simple uncorrelated branching process. [less ▲]

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See detailPurification of Progelatinases A and B by Continuous-Elution Electrophoresis
Remacle, A. G.; Baramova, E. N.; Weidle, U. H. et al

in Protein Expression & Purification (1995), 6(4), 417-22

Progelatinases A and B were purified from HT1080-conditioned culture medium using a continuous-elution electrophoresis. Initially cell culture medium was ammonium sulfate precipitated. The concentrated ... [more ▼]

Progelatinases A and B were purified from HT1080-conditioned culture medium using a continuous-elution electrophoresis. Initially cell culture medium was ammonium sulfate precipitated. The concentrated proteins were affinity chromatographed on gelatin-Sepharose column. The bound gelatinases were eluted with electrophoresis sample buffer and subjected to continuous-elution electrophoresis. In a single run, under the standardized working conditions, the obtained fractions contained four purified enzymes--progelatinase A (M(r) 72,000), its activated forms (M(r) 62,000 and M(r) 59,000), and progelatinase B (M(r) 92,000). Moreover, the continuous-elution electrophoresis allowed the enzymes separation from their respective inhibitors--TIMP-1 (M(r) 28,500) and TIMP-2 (M(r) 21,000). The purified progelatinases A and B demonstrated high specific activities (150-200 U/micrograms). [less ▲]

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See detailApproaches to the optimal navigation organization on the inland waterway network
Marchal, Jean ULg; Zhang, Z. M.

in Procceedings of the First Symposium on Operation Research with Application in Engineering, Technology and Management (ISORA’95) (1995)

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See detailSoluble Interleukin-2 Receptor in Crohn's Disease. Assessment of Disease Activity and Prediction of Relapse
Louis, Edouard ULg; Belaiche, Jacques ULg; Van Kemseke, Catherine ULg et al

in Digestive Diseases & Sciences (1995), 40(8), 1750-6

In Crohn's disease, the activity of the disease is difficult to evaluate and the evolution of the disease is difficult to predict. The soluble interleukin-2 receptor serum level has been reported to ... [more ▼]

In Crohn's disease, the activity of the disease is difficult to evaluate and the evolution of the disease is difficult to predict. The soluble interleukin-2 receptor serum level has been reported to correlate with clinical activity of the disease and with mucosal immune activation. We compared serum soluble interleukin-2 receptor to classical inflammatory markers and other immune parameters in the assessment of clinical disease activity and prediction of relapse in patients with Crohn's disease. Soluble interleukin-2 receptor serum levels correlated well with the Crohn's disease activity index, and multivariate analysis showed that this correlation was independent of the other inflammatory and immune markers. The correlation was not greater, However, than that between some inflammatory markers, such as ESR, and Crohn's disease activity index. Longitudinal follow-up showed that a high soluble interleukin-2 receptor serum level was highly predictive of relapse. Multivariate analysis showed that the soluble interleukin-2 recepteur serum level was complementary to other inflammatory and clinical markers in the prediction of relapse of disease. We conclude that soluble interleukin-2 receptor is of use in monitoring Crohn's disease, particularly in prediction of relapse. [less ▲]

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See detailMicroencapsulation by coacervation of poly(lactide-co-glycolide). IV. Effect of the processing parameters on coacervation and encapsulation
Nihant, N.; Grandfils, Christian ULg; Jérôme, Robert ULg et al

in Journal of Controlled Release (1995), 35(2-3), 117-125

Attention has been paid to phase separation of poly (lactide-co-glycolide) solutions in CH2Cl2 induced by the addition of a silicone oil in order to promote protein microencapsulation. Since the process ... [more ▼]

Attention has been paid to phase separation of poly (lactide-co-glycolide) solutions in CH2Cl2 induced by the addition of a silicone oil in order to promote protein microencapsulation. Since the process is very fast, the system is anytime out of equilibrium. The effect of the main processing parameters on the microencapsulation process has been analyzed and has highlighted that kinetics of the main encapsulation steps has a great effect on the characteristics of the final microspheres. These results have been discussed on the basis of a physico-chemical study of coacervation reported in previous papers of this series. [less ▲]

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See detailCytogenetic study of bovine oocytes matured in vitro
Ectors, Fabien ULg; Koulischer, Lucien ULg; Jamar, M. et al

in Theriogenology (1995), 44(3), 445-450

Described in the present paper is a cytogenetic study of bovine oocytes matured in vitro. The cumulus-oocyte complexes (COC), punctured from ovaries recovered in a local slaughterhouse, were classified ... [more ▼]

Described in the present paper is a cytogenetic study of bovine oocytes matured in vitro. The cumulus-oocyte complexes (COC), punctured from ovaries recovered in a local slaughterhouse, were classified into 3 groups according to follicular diameter 1 to 4mm, 5 to 8mm and 9 to 13 mm. Metaphases available for observation were classified as metaphase I, haploid and diploid metaphase II. High levels of haploid metaphases II (90.6, 86.9 and 94.4 %) among the 3 groups of follicular sizes indicated successful meiotic resumption during in vitro maturation and suggested that cytoplasmic maturation may be responsible for low developmental rate after IVM, IVF and in vitro development (IVD). [less ▲]

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See detailGlycoproteins of the aspartyl proteinase gene family secreted by the developing placenta
Roberts, R. M.; Xie, S.; Nagel, R. J. et al

in Advances in Experimental Medicine and Biology (1995)

Pregnancy in cattle and sheep can be diagnosed by the presence of placentally-derived antigens (pregnancy-associated glycoproteins or PAG-1) in maternal serum soon after implantation begins at about Day ... [more ▼]

Pregnancy in cattle and sheep can be diagnosed by the presence of placentally-derived antigens (pregnancy-associated glycoproteins or PAG-1) in maternal serum soon after implantation begins at about Day 20 following conception. Molecular cloning of their cDNA has revealed that PAG-1 belong to the aspartic proteinase gene family and have about 50% amino acid sequence identity to pepsin. However, critical amino acid substitutions at the active site regions suggest that both bovine and ovine PAG-1 are enzymatically inactive. PAG-1 expression has been shown by in situ hybridization and immunocytochemistry to be localized to the trophoblast binucleate cells, which invade maternal uterine endometrium during implantation. The glycoproteins are concentrated in dense cytoplasmic granules that are discharged after the binucleate cells have migrated to the maternal side of the placental barrier. We suggest, therefore, that the PAG-1 might have an endocrine function either as carriers of other bioactive peptides or by acting as hormones themselves. Recently screening of placental libraries with nucleic acid probes has identified additional cDNA that are very abundant and code for polypeptides (PAG-2 and PAG-3) related to, but antigenically and structurally distinct from PAG-1 described above. These molecules have sequences of amino acids at their catalytic centers that are consistent with their being potentially functional proteinases but their role during pregnancy, like that of PAG-1, is unclear. [less ▲]

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See detailInteractions Traditions Orales et Blues dans SULA, un roman de Toni Morrison
Sacré, Robert ULg

in Actes-Handelingen-Akten Congrès de Liège , III (1995, August)

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See detailA new distribution of vegetation types and its inclusion in a global biosphere model
Warnand; François, Louis ULg; Nemry, B. et al

Poster (1995, August)

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See detailPharma-clinics. Le médicament du mois. La terbinafine (Lamisil)
Pierard, Gérald ULg

in Revue Médicale de Liège (1995), 50(8), 352-3

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See detailAggregation behavior of ω- and α,ω-metal sulfonato polystyrene in toluene
Vanhoorne, Pierre ULg; Jérôme, Robert ULg

in Macromolecules (1995), 28(16), 5664-5670

The aggregation behavior of omega- and alpha,omega-metal sulfonato polystyrene in toluene has been investigated by static and dynamic light scattering. Monofunctional chains reversibly associate into ... [more ▼]

The aggregation behavior of omega- and alpha,omega-metal sulfonato polystyrene in toluene has been investigated by static and dynamic light scattering. Monofunctional chains reversibly associate into small reverse micelles. Lithium-based ionic aggregates contain an average of 12 ion pairs, which corresponds to a preferential structure for the ionic cores. When the molecular weight of the chains is increased, polymer-solvent interactions progressively distort the ionic aggregates, and above a critical molecular weight, estimated to be 50000 in toluene, the multiplets collapse into smaller aggregates of an average of 3 ion pairs. Traces of polar solvents do not strongly affect the aggregation number, but do weaken the dipole-dipole interactions. Structure of the ionic cores strongly depends on the nature of the ion pairs, which suggests that this structural feature is a key parameter in the control of the structure-property relationships in ionomers. The aggregation behavior of the difunctional chains is complex, due to the occurrence of a closed association mechanism for the individual multiplets and an open association of reverse micelles into larger aggregates. [less ▲]

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See detailAPRIL 1993 ARCTIC PROFILES OF STRATOSPHERIC HCL, CLONO2, AND CCL2F2 FROM ATMOSPHERIC TRACE MOLECULE SPECTROSCOPY ATLAS 2 INFRARED SOLAR OCCULTATION SPECTRA
Rinsland, C. P.; Gunson, M. R.; Abrams, M. C. et al

in Journal of Geophysical Research (1995), 100(D7), 14019-14027

Partitioning among the major components of the stratospheric odd chlorine family inside and outside of the remanent Arctic vortex has been studied on the basis of infrared solar occultation measurements ... [more ▼]

Partitioning among the major components of the stratospheric odd chlorine family inside and outside of the remanent Arctic vortex has been studied on the basis of infrared solar occultation measurements obtained by the atmospheric trace molecule spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS 2 shuttle mission (April 8-17, 1993). Profiles of hydrogen chloride (HCl) and simultaneous profiles of chlorine nitrate (ClONO2) and CFC-12 (CCl2F2) are reported for examples of in-vortex and out-of-vortex conditions. Increased ClONO2 volume-mixing ratios (VMRs) are measured in the vortex below 20 mbar (similar to 25 km altitude) with a peak ClONO2 VMR of 2.05 +/- 0.45 ppbv (10(-9) per volume) at 56 mbar (similar to 19 km altitude). The reported error correspond to la uncertainties. Simultaneous CCl2F2 and N2O measurements, combined with published empirical relations, indicate that only 0.34 +/- 0.15 ppbv, about 10% of total chlorine, was bound in organic species at the ClONO2 VMR peak in the vortex. A colocated vortex profile of HCl, referenced to simultaneous N2O VMR measurements, has been used to derive a HCl mixing ratio of 1.21 +/- 0.12 ppbv corresponding to the ClONO2 VMR peak. The internal consistency of the ATMOS measurements is demonstrated by the agreement between the total chlorine mixing ratio of 3.60 +/- 0.72 ppbv derived at the ClONO2 VMR peak in the vortex and HCl measurements of 3.37 +/- 0.37 and 3.76 +/- 0.41 ppbv at 0.56 mbar, where HCl is the only significant chlorine-bearing molecule. Outside the vortex the mixing ratio of HCl exceeds the mixing ratio of ClONO2 throughout the stratosphere. [less ▲]

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See detailStereocomplexation and morphology of polylactides
Brochu, Sylvie; Prud'homme, Robert E; Barakat, Ibrahim et al

in Macromolecules (1995), 28(15), 5230-5239

Blends of isotactic polylactides of opposite configurations lead to the formation of stereocomplexes, provided the enantiomeric excess of the two homopolymers in contact is high enough. In this study, the ... [more ▼]

Blends of isotactic polylactides of opposite configurations lead to the formation of stereocomplexes, provided the enantiomeric excess of the two homopolymers in contact is high enough. In this study, the stereocomplex formation between a poly(L-lactide) (100L) having an enantiomeric excess of 100% and a poly(D-lactide) having an enantiomeric excess of 80% (80D) has been investigated using differential scanning calorimetry and optical microscopy. These results have been compared to those obtained between two polylactides having both an enantiomeric excess of 100% (100L/100D blend). The melting temperatures of blends 100L/100D and 100L/80D are 230 and 208 degrees C, respectively. In both cases, the stereocomplex formation is preferred to the homopolymer crystallization and the stereocomplex controls the morphology of the blends over a wide range of concentrations. However, this control is more rigorous when the D component is 100% isotactic. This difference leads to a more complete crystallization of homopolymer 100L and to a greater influence of crystallization conditions in 100L/80D blends in comparison with 100L/100D blends. An epitaxial crystallization between the homopolymer 100L and the stereocomplex 100L/80D has also been observed at certain compositions. [less ▲]

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See detailBlends of biphasic ionomers with chemically identical mono- and bifunctional oligomers
Plante, Michel; Bazuin, C Géraldine; Jérôme, Robert ULg

in Macromolecules (1995), 28(15), 5240-5247

Biphasic Cs and Ba carboxylated polystyrene ionomers were blended with chemically identical mono- and bifunctional oligomers whose chain lengths are significantly greater than the average segmental length ... [more ▼]

Biphasic Cs and Ba carboxylated polystyrene ionomers were blended with chemically identical mono- and bifunctional oligomers whose chain lengths are significantly greater than the average segmental length between ionic groups in the ionomer. The ionomers were chosen to have two ion contents such that, in one case, the matrix phase is dominant and, in the other, the cluster phase is dominant. From dynamic mechanical thermal analysis, it was observed that the biphasic morphology of the ionomers is preserved in all blends (containing up to 60 wt % oligomer). The monofunctional oligomers tend to have a mild plasticizing action on the two phases. In the matrix-dominated ionomer, the bifunctional oligomer has an antiplasticization effect at lower oligomer contents; this is attributed to a greater dispersion of ionic aggregates in the matrix phase, accompanied by pinning of the oligomer extremities in multiplets, which prevents plasticizing action. In the cluster-dominated ionomer, the oligomer forms a separate phase, which is related to insufficiently large ion-poor styrene regions in the ionomer to accommodate the long nonionic portion of the oligomer chains. [less ▲]

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See detailLatent Bovine Herpesvirus 1 Infection in Calves Protected by Colostral Immunity
Lemaire, Mylène; Meyer, Gilles; Ernst, E. et al

in Veterinary Record : Journal of the British Veterinary Association (1995), 137(3), 70-1

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See detailQuantitative estimation of chitin and proteins in the cuticle of five species of Priapulida
Saldarriaga, Juan F.; Voss-Foucart, Marie-Françoise; Compère, Philippe ULg et al

in Sarsia. North Atlantic Marine Science (1995), 80

The biochemical composition ofthe cuticle of 5 species of Priapulida was tested using a specific enzymatic method for the determination of chitin, and a lectin-labelling technique for its ultrastructural ... [more ▼]

The biochemical composition ofthe cuticle of 5 species of Priapulida was tested using a specific enzymatic method for the determination of chitin, and a lectin-labelling technique for its ultrastructural location. The integument of all species tested contains 4–15 % chitin and 9–85 % protein. Chitin could be located in both layers of the priapulid cuticle, even though their ultrastructural morphology differs. The results of this work suggest a close relationship between the Priapulida and the Kinorhyncha, the only other group of Aschelminths known to have a chitinous cuticle. [less ▲]

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