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See detailAn enhanced process for the production of a highly purified extracellular lipase in the non-conventional yeast Yarrowia lipolytica
Turki, S.; Ayed, A.; Chalghoumi, N. et al

in Applied Biochemistry and Biotechnology (2010), 160(5), 1371-1385

Yarrowia lipolytica LgX64.81 is a non-genetically modified mutant that was previously identified as a promising microorganism for extracellular lipase production. In this work, the development of a fed ... [more ▼]

Yarrowia lipolytica LgX64.81 is a non-genetically modified mutant that was previously identified as a promising microorganism for extracellular lipase production. In this work, the development of a fed-batch process for the production of this enzyme in this strain was described. A lipolytic activity of 2,145 U/mL was obtained after 32 h of batch culture in a defined medium supplemented with 10 g/L of tryptone, an enhancer of lipase expression. To maximize the volumetric productivity, two different fed-batch strategies had been investigated. In comparison to batch process, the intermittent fed-batch strategy had not improved the volumetric lipase productivity. In contrast, the stepwise feeding strategy combined with uncoupled cell growth and lipase production phases resulted in a 2-fold increase in the volumetric lipase productivity, namely, the lipase activity reached 10,000 U/mL after 80 h of culture. Furthermore, this lipase was purified to homogeneity by anion exchange chromatography on MonoQ resin followed by gel filtration on Sephacryl S-100. This process resulted in an overall yield of 72% and a 3.5-fold increase of the specific lipase activity. The developed process offers a great potential for an economic production of Lip2 at large scale in Y. lipolytica LgX64.81. © 2009 Humana Press. [less ▲]

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See detailEnhanced proof strength after cold process of fabrication of non-linear metallic profiles – Comparison of two predictive models for hollow sections
Rossi, Barbara ULg; Jaspart, Jean-Pierre ULg

in International Symposium on Tubular Structures : ISTS13, Hong Kong, 15-17 December 2010 (2010)

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See detailEnhanced Release of Plasminogen Activator Inhibitor(S) but Not of Plasminogen Activators by Cultured Rat Glial Cells Treated with Interleukin-1
Rogister, Bernard ULg; Leprince, Pierre ULg; Delree, P. et al

in Glia (1990), 3(4), 252-7

Astroglial cells are known to proliferate during development of the nervous system, as well as during post-traumatic gliosis. We have previously shown that the proliferation of cultured astrocytes can be ... [more ▼]

Astroglial cells are known to proliferate during development of the nervous system, as well as during post-traumatic gliosis. We have previously shown that the proliferation of cultured astrocytes can be stimulated by the urokinase-type (uPA) of plasminogen activator (PA) and that astrocytes are able to release such uPA upon stimulation with basic fibroblast growth factor, which is known to act as a mitogen for these cells. Here we report studies on the effects of human interleukin-1 (IL-1) on the release of PA activity by cultured newborn rat astroglial cells. Whereas there is controversy in the literature as to whether IL-1 stimulates multiplication of astroglial cells, we failed to observe such an effect in our system. We did observe, however, a dose-dependent decrease in PA activity in the supernatant of the IL-1 treated cultures. Further analysis revealed that this apparent decrease in PA release was in fact due to an increased release of plasminogen activator inhibitor (PAI). A similar IL-1 induced increase in PAI release was also found to occur in cultures of transformed astrocytes (human glioma LN18) and in cultured Schwann cells, but not in cultures of neurons or neuronal tumour cells. Since protease inhibitors are known to possess neuritogenic properties, our results suggest that IL-1, by its capacity to induce PAI, may promote neuritogenesis. [less ▲]

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See detailEnhanced survival of lung granulocytes in an animal model of asthma : evidence for a role of GM-CSF-activated STAT5 signaling pathway
Turlej, R.; Sandersen, Charlotte ULg; Fievez, Laurence ULg et al

in Proceedings: International Conference of the American Thoracic Society (2001)

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See detailEnhanced survival of lung granulocytes in an animal model of asthma: evidence for a role of GM-CSF activated STAT5 signalling pathway
Turlej, Renata K; Fievez, Laurence ULg; Sandersen, Charlotte ULg et al

in Thorax (2001), 56(9), 696-702

As granulocyte/macrophage colony stimulating factor (GM-CSF) mediated delay of granulocyte apoptosis contributes to the accumulation of inflammatory cells at the site of inflammation in many diseases, we ... [more ▼]

As granulocyte/macrophage colony stimulating factor (GM-CSF) mediated delay of granulocyte apoptosis contributes to the accumulation of inflammatory cells at the site of inflammation in many diseases, we sought to determine whether asthma is also associated with a GM-CSF dependent increase in lung granulocyte survival. Moreover, because GM-CSF mediates its effects through activation of signal transducer and activator of transcription 5 (STAT5), we also investigated the potential role of STAT5 in allergic inflammation. METHODS: Blood granulocytes were recovered from six healthy and six heaves affected horses, a model of asthma. Lung granulocytes were obtained by bronchoalveolar lavage (BAL) from the same horses. Granulocytes were cultured in the presence or absence of anti-GM-CSF receptor antibodies for different times and apoptosis was determined using the Annexin-V/propidium iodide detection method. Nuclear protein extracts from cultured granulocytes were analysed for STAT5 binding activity by electrophoretic mobility shift assay. RESULTS: BAL fluid granulocytes from heaves affected horses demonstrated a significant delay in apoptosis compared with blood granulocytes from the same horses and blood and BAL fluid granulocytes from healthy horses. Conversely, the rate of apoptosis in blood granulocytes from healthy and heaves affected horses was comparable. The enhanced survival of BAL fluid granulocytes from affected horses was suppressed in the presence of antibodies directed against GM-CSF receptors. Increased levels of active STAT5 were found in BAL fluid granulocytes from heaves affected horses and were markedly reduced after treatment with anti-GM-CSF receptor antibodies. CONCLUSIONS: These data indicate that granulocyte survival is enhanced in the lung of heaves affected horses and suggest a role for a GM-CSF activated STAT5 pathway in delaying apoptosis of lung granulocytes in this model of asthma. [less ▲]

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See detailEnhanced susceptibility of focal ischemic in jury in mice lacking prostacyclin receptors
Huang, Zihong; Austin, S.; Salomone, Salvatore et al

Poster (2002)

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See detailEnhanced tropospheric HCN columns above Kitt Peak during the 1982-1983 and 1997-1998 El Nino warm phases
Rinsland, Curtis P.; Goldman, Aaron; Zander, Rodolphe ULg et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2001), 69(1), 3-8

Free tropospheric HCN columns have been derived from infrared solar spectra recorded with the National Solar Observatory Fourier transform spectrometer on Kitt Peak, Arizona (31.9ºN latitude, 111.6ºW ... [more ▼]

Free tropospheric HCN columns have been derived from infrared solar spectra recorded with the National Solar Observatory Fourier transform spectrometer on Kitt Peak, Arizona (31.9ºN latitude, 111.6ºW longitude, 2.09 km altitude) between May 1978 and May 2000. The time series show up to a factor of 2.4 enhancement during the strong El Ninos of 1982-1983 and 1997-1998, the most intense since 1970. The observations provide confirmation that HCN is a sensitive tracer of biomass burning emissions transported to the free troposphere. No statistically significant long-term trend in the HCN-free tropospheric column has been detected over the 22-year measurement period. The results illustrate the importance of long-term spectroscopic measurements for quantifying climate and atmospheric chemistry-related atmospheric changes. [less ▲]

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See detailEnhanced urinary odor discrimination in female aromatase knockout (ArKO) mice
Wesson, D. W.; Keller, Matthieu ULg; Douhard, Quentin ULg et al

in Hormones & Behavior (2006), 49(5), 580-586

We asked whether odor discrimination abilities are sexually dimorphic in mice and, if so, whether the perinatal actions of estradiol contribute to these sex differences. The ability to discriminate ... [more ▼]

We asked whether odor discrimination abilities are sexually dimorphic in mice and, if so, whether the perinatal actions of estradiol contribute to these sex differences. The ability to discriminate different types of urinary odors was compared in male and female wild-type (WT) subjects and in mice with a hornozygous-null mutation of the estrogen synthetic enzyme, aromatase (aromatase knockout; ArKO). Olfactory discrimination was assessed in WT and ArKO male and female mice after they were gonadectomized in adulthood and subsequently treated with estradiol benzoate. A liquid olfactometer was used to assess food-motivated olfactory discrimination capacity. All animals eventually learned to distinguish between urinary odors collected from gonadally intact males and estrous females; however, WT males as well as ArKO mice of both sexes learned this discrimination significantly more rapidly than WT females. Similar group differences were obtained when mice discriminated between urinary odors collected from gonadally intact vs. castrated males or between two non-social odorants, amyl and butyl acetate. When subjects had to discriminate volatile urinary odors from ovariectomized female mice treated with estradiol sequenced with progesterone versus estradiol alone, ArKO females quickly acquired the task whereas WT males and females as well as ArKO males failed to do so. These results demonstrated a strong sex dimorphism in olfactory discrimination ability, with WT males performing better than females. Furthermore, female ArKO mice showed an enhanced ability to discriminate very similar utinary odorants, perhaps due to an increased sensitivity of the main olfactory nervous system to adult estradiol treatment as a result perinatal estrogen deprivation. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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See detailAn enhanced version of a bone remodelling model based on the continuum damage mechanics theory.
Mengoni, Marlène ULg; Ponthot, Jean-Philippe ULg

in Computer Methods in Biomechanics & Biomedical Engineering (in press)

The purpose of this work is to propose an enhancement of Doblaré and García's internal bone remodelling model based on the continuum damage mechanics theory. In their paper, they stated that the evolution ... [more ▼]

The purpose of this work is to propose an enhancement of Doblaré and García's internal bone remodelling model based on the continuum damage mechanics theory. In their paper, they stated that the evolution of the internal variables of the bone microstructure, and its incidence on the modification of the elastic constitutive parameters, may be formulated following the principles of Continuum Damage Mechanics, although no actual damage was considered. The resorption and apposition criteria (similar to the damage criterion) were expressed in terms of a mechanical stimulus. However, the resorption criterion is lacking a dimensional consistency with the remodelling rate. We here propose an enhancement to this resorption criterion, insuring the dimensional consistency while retaining the physical properties of the original remodelling model. We then analyse the change in the resorption criterion hypersurface in the stress space for a 2D analysis. We finally apply the new formulation to analyse the structural evolution of a 2D femur. This analysis gives results consistent with the original model but with a faster and more stable convergence rate. [less ▲]

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See detailAn Enhanced Version of Timed LOTOS and its Application to a Case study
Léonard, Luc; Leduc, Guy ULg

in Tenney, R. L.; Amer, P. D.; Uyar, M. U. (Eds.) FORMAL DESCRIPTION TECHNIQUES, VI (1993, October)

We propose here ET-LOTOS, a timed extension of LOTOS. It is an enhancement of Timed LOTOS that we presented at FORTE 92. We show how some simple modifications allow us to improve the expressiveness of our ... [more ▼]

We propose here ET-LOTOS, a timed extension of LOTOS. It is an enhancement of Timed LOTOS that we presented at FORTE 92. We show how some simple modifications allow us to improve the expressiveness of our former formalism. To assess ET-LOTOS, we apply it to the specification of a small case study. Finally, we show how the semantics of ET-LOTOS could be modified to easily define more powerful operators, if one ever had to. [less ▲]

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See detailEnhanced vortex pinning by a composite antidot lattice in a superconducting Pb film
Silhanek, Alejandro ULg; Van Look, L.; Jonckheere, R. et al

in Physical Review. B : Condensed Matter (2005), 72(1),

The use of artificial defects is known to enhance the superconducting critical parameters of thin films. In the case of conventional superconductors, regular arrays of submicron holes (antidots ... [more ▼]

The use of artificial defects is known to enhance the superconducting critical parameters of thin films. In the case of conventional superconductors, regular arrays of submicron holes (antidots) substantially increase the critical temperature T-c(H) and critical current I-c(H) for all fields. Using electrical transport measurements, we study the effect of placing an additional small antidot in the unit cell of the array. This composite antidot lattice consists of two interpenetrating antidot square arrays with a different antidot size and the same lattice period. The smaller antidots are located at the centers of the cells of the large antidots array. We show that the composite antidot lattice can trap a higher number of flux quanta per unit cell inside the antidots compared to a reference antidot film without the additional small antidots. As a consequence, the field range in which an enhanced critical current is observed is considerably expanded. Finally, the possible stable vortex lattice patterns at several matching fields are determined by molecular-dynamics simulations. [less ▲]

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See detailEnhanced vortex trapping by a composite antidot lattice in a superconducting Pb film
Silhanek, Alejandro ULg; Van Look, L.; Jonckheere, R. et al

in Physica C: Superconductivity (2007), 460

Using electrical transport measurements, we study a composite antidot lattice consisting of two interpenetrating antidot square arrays with a different antidot size and the same lattice period. We show ... [more ▼]

Using electrical transport measurements, we study a composite antidot lattice consisting of two interpenetrating antidot square arrays with a different antidot size and the same lattice period. We show that placing an additional small antidot in the unit cell of the array a higher number of flux quanta per unit cell can be trapped inside the antidots, compared to a reference antidot film without the additional small antidots. As a consequence, the field range in which an enhanced critical current is observed is considerably expanded. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailEnhancement and parametric analysis of a model of a drilling assembly equipped with a rotary steerable system
Huynen, Alexandre ULg

Master's dissertation (2010)

Demand in products derived from crude oil and the decrease of the gas and petroleum reserves have been boosting the petroleum industry to always beat back the limit between reserves and resources ... [more ▼]

Demand in products derived from crude oil and the decrease of the gas and petroleum reserves have been boosting the petroleum industry to always beat back the limit between reserves and resources, explaining why the interest for directional drilling has been growing up during the last several decades. Nowadays, rotary steerable systems are so efficient that they are becoming the benchmark for the industry. More than one million feet of well-bore are drilled every year using this technology. The drilling industry handles dimensions and times that cover several order of magnitude. The time scale ranges from seconds for the bit revolution to days for the drilling of a well, while the length scale ranges from hundredth of millimetres for the penetration parameters of a bit in a rock formation to kilometres for the length of a drillstring. This makes the drilling industry such an unfamiliar field which confronts engineers to unconventional challenges. This complexity may explain why, despite the substantial resources of the oil industry, direc- tional drilling processes are still misapprehended. Indeed, the industry continues to rely on trial and error to control the direction of an oil well. Nevertheless, relatively recent theories try to com- prehend the directional behaviour of a drilling assembly in order to predict, with relative success, the geometry of the borehole drilled. Mathematical models of the near-bit region of the drillstring already exist. However the literature covers especially drilling assembly equipped with a push- the-bit system. The main purpose of the second part of this work is to develop a mathematical model of a drilling assembly equipped with a point-the-bit system. This one is an enhancement of the Mathematical Model of the Near-Bit Region of an Advancing Drilling System developed by Detournay (2007). The model is composed of three interacting components: (i) the equations governing the geometrical evolution of the borehole, (ii) the laws that link the kinematical bit-rock penetration variables to the forces on the bit, and (iii) the relationships between the forces on the bit and the loads on the drillstring. The third part of this work presents the results of a parametric analysis of this mathematical model. The parametric analysis, led in the framework of planar borehole trajectories and stationary solutions, focus on the the borehole curvature and distinguishes the two configurations of the BHA: with and without rotary steerable system. Finally, a brief case study of a commercialised point-the-bit system is presented in the fourth part. The goal of this last section is to validate the mathematical model developed and highlight the limitations of this one. Some commonly accepted thoughts are also approached. [less ▲]

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See detailEnhancement effects in exclusive ππ and ρπ production in γ* γ scattering
Courtoy, Aurore ULg; Noguera, S.

in Physics Letters B (2009), 675(1), 38-42

The exclusive ππ and ρπ production in hard γ* γ scattering in the forward kinematical region where the virtual photon is highly off-shell is studied using the γ → π- Transition Distribution Amplitudes ... [more ▼]

The exclusive ππ and ρπ production in hard γ* γ scattering in the forward kinematical region where the virtual photon is highly off-shell is studied using the γ → π- Transition Distribution Amplitudes obtained in realistic models for the pion. For ρπ production we confirm the previous estimates before QCD evolution. Nevertheless, once evolution is taken into account this cross section grows one order of magnitude. In the case of ππ production we have evaluated the cross section including the pion pole contribution. We observe that this contribution is responsible for an enhancement of two orders of magnitude with respect to the cross section evaluated without the pion pole term. © 2009 Elsevier B.V. All rights reserved. [less ▲]

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See detailEnhancement of 1,3-bis(2-chloroethyl)-1-nitrosourea resistance by gy gamma-irradiation or drug pretreatment in rat hepatoma cells
Habraken, Yvette ULg; Laval, Françoise

in Cancer Research (1991), 51(4), 499-503

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See detailEnhancement of bovine leukemia virus-induced syncytia formation by di- and tripeptides.
Voneche, V.; Callebaut, I.; Lambrecht, B. et al

in Virology (1993), 192(1),

Short hydrophobic peptides were previously shown to inhibit infectivity of para- and orthomyxoviruses. We tested the ability of a series of di- and tripeptides to interfere with cell fusion induced by ... [more ▼]

Short hydrophobic peptides were previously shown to inhibit infectivity of para- and orthomyxoviruses. We tested the ability of a series of di- and tripeptides to interfere with cell fusion induced by bovine leukemia virus (BLV). Peptides containing a hydrophobic contribution and/or a positive net charge strongly enhanced syncytia formation induced by BLV on CC81 indicator cells. The size of the multinucleated cells was strongly increased (up to 10-fold) in the presence of the enhancer peptides whereas no effect was observed on the indicator cells in the absence of BLV. The peptides thus amplified the fusion process initiated by BLV envelope glycoproteins. The effect was dose-dependent at concentrations ranging from 20 to 640 microM and did not result from an increased expression of BLV proteins. The peptides did not compete with anti-gp51 monoclonal antibodies for the recognition of eight well-defined epitopes of gp51. We consequently hypothesize that the enhancer peptides interact with the membrane of BLV-producing cells and/or indicator cells and propose a model based on molecular modeling. [less ▲]

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