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See detailEnhancement of thermophillic anaerobic digestion of methane by metal nanoparticles encapsulated in porous silica
Al-Ahmad, Alaa Eddin ULg; Hiligsmann, Serge ULg; Lambert, Stéphanie ULg et al

Poster (2013, December 05)

Increased demand and progressive depletion of fossil fuels, and worldwide concerns about greenhouse gas emissions have resulted in the development of promising technologies for renewable energy production ... [more ▼]

Increased demand and progressive depletion of fossil fuels, and worldwide concerns about greenhouse gas emissions have resulted in the development of promising technologies for renewable energy production. Therefore, potential alternatives for energy generation are intensively studied. One option is the use of biomass feedstock for the production of biogas through anaerobic digestion. This process is a biochemical technological process for the treatment of a wide range of feedstocks (e.g. organic fraction of municipal waste, animal manure and slurry, agricultural crops, etc.) to produce methane-rich biogas which can be used in replacement of fossil fuels in both heat and power generation and as a vehicle fuel. However, there are critical issues, which need to be addressed to make the production of bio-methane techno-economically viable and ecologically acceptable. One of the most important issues is the effect of trace metals addition on anaerobic digestion. These metals can be stimulatory, inhibitory, or even toxic for biochemical reactions, depending on their concentrations. As reported in literature, Ni, Co and Fe are all involved in the methane production biochemical process and serve as cofactors in enzymes which are involved in the biochemistry of methane formation (Zandvoort et al., 2006). Recently, enormous interest has been focused on biological applications of metal nanoparticles NPs due to their small size, high specified surface and their great potential in application to many science fields. The most studied process concerns zero valent palladium and iron NPs improving anaerobic biodegradation of chlorinated hydrocarbons (Windt et al., 2005). Moreover, investigation carried out in our lab showed that iron NPs encapsulated in silicate matrix may enhance hydrogen production by Clostridium butyricum (Beckers et al., 2013). Nevertheless the influences of metal NPs on methane producing anaerobic digestion have seldom been investigated. The present work investigates the enhancement effect of seven different metal NPs on methane production during the thermophilic anaerobic digestion. NPs of Cu, Pd, Pt, Ni, Co, Ag and Fe encapsulated in porous silica (SiO2) to prevent their coagulation and agglomeration, were added at concentration of 10-5mol/L in batch test (125ml serum bottles containing 70mL culture medium with 5g/L acetate monohydrate as the sole carbon substrate. Nickel, cobalt and iron NPs improved methane production from acetate. To confirm the previous results, the NPs were tested at different concentrations (10-4, 10-5, and 10-6 mol/L) with starch and glucose substrates. The results show that the impact increases with the increase of NPs concentrations up to 10-4 mol/L. The modified Gompertz equation was applied to describe the effect of NPs on anaerobic digestion. According to this model, the kinetic of methane production was particularly affected by nanoparticles addition. The values of the maximum methane production rate MPR (ml/day) was significantly higher 72.5% with nickel NPs at a concentration of 10-4 mol/L than the control without NPs. [less ▲]

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See detailEnhancement of Total Electron Content monitoring using triple frequency GNSS data
Spits, Justine; Warnant, René ULg

Conference (2011, August 31)

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See detailEnhancement of transfection efficiency through rapid and noncovalent post-PEGylation of poly(dimethylaminoethyl methacrylate)/DNA complexes
Pirotton, S.; Muller, Caroline; Pantoustier, N. et al

in Pharmaceutical Research (2004), 21(8), 1471-1479

Purpose. The aim of this work was to develop a new strategy to introduce poly(ethylene glycol) (PEG) into methacrylate-based polymer/ DNA complexes in order to produce hemocompatible particles able to ... [more ▼]

Purpose. The aim of this work was to develop a new strategy to introduce poly(ethylene glycol) (PEG) into methacrylate-based polymer/ DNA complexes in order to produce hemocompatible particles able to transfect cells in the presence of serum. Methods. Atom transfer radical polymerization was used to synthesize a well-defined poly(2-(dimethylamino) ethyl methacrylate) homopolymer ( PDMAEMA) and a poly( 2-( dimethylamino) ethyl methacrylate-b-poly( ethylene glycol) alpha-methyl ether, omega-methacrylate) palm-tree-like copolymer (P(DMAEMA-b-MAPEG)). The complexes obtained by self assembly of the pCMVbeta plasmid and the polymers were used to transfect Cos-7 cells. Their physical properties - particle size and zeta potential - were characterized respectively by dynamic light scattering and electrophoretic mobility measurements. Ex vivo hemocompatibility was also determined. Results. The PDMAEMA/pCMVbeta complexes transfected Cos-7 cells exclusively in the absence of serum. Although the P(DMAEMA-b-MAPEG) copolymer had no transfection activity per se, the addition of the latter to pre-formed PDMAEMA/DNA complexes significantly enhanced the activity and allowed transfection even in the presence of serum. The presence of palm-tree - like copolymers also improved the hemocompatibility properties of the complexes. No effect on platelet counts was observed for P(DMAEMA-b-MAPEG)/ pCMVbeta complexes, whereas a decrease of platelets was clearly observed when blood cells were incubated with PDMAEMA/pCMVbeta complexes. Conclusions. Such a synergistic effect of noncovalent PEGylation of poly( amino methacrylate)/ DNA complexes allows a new and versatile approach to tune up transfection efficiency. [less ▲]

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See detailEnhancement of Tumorigenicity of Human Breast Adenocarcinoma Cells in Nude Mice by Matrigel and Fibroblasts
Noël, Agnès ULg; Gillet, Marie-Claire ULg; Purnell, G. et al

in British Journal of Cancer (1993), 68(5), 909-15

The failure of MCF7 cells to induce the formation of tumours after sub-cutaneous inoculation into athymic nude mice can be obviated by the simultaneous injection of an extract of basement membrane ... [more ▼]

The failure of MCF7 cells to induce the formation of tumours after sub-cutaneous inoculation into athymic nude mice can be obviated by the simultaneous injection of an extract of basement membrane proteins (matrigel). Tumour growth is promoted and the latency period is low (2 to 4 weeks). In the absence of matrigel, the simultaneous inoculation of fibroblasts and MCF7 cells also resulted in the development of tumours, but with a longer latency period (about 2 months). The tumorigenic synergy between matrigel and fibroblasts was evidenced by co-inoculating MCF7 cells MDA-MB 231 cells with fibroblasts and matrigel. This co-inoculation decreased the delay of appearance of the tumours and/or accelerated the tumour growth, depending upon the number of fibroblasts injected. Repeated injections of fibroblasts conditioned medium, at the site of inoculum of tumour cells also enhanced tumour growth, suggesting the involvement of soluble factors secreted by fibroblasts. Histologically, tumours induced by co-inoculation of tumour cells and fibroblasts contained more stromal structures including vimentin-positive cells, fibronectin and interstitial collagens. These data suggest that human tumours may be reconstituted and grown in athymic nude mice using basement membrane components and fibroblasts as inductors. [less ▲]

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See detailEnhancement of Varicella-Zoster virus infection in cell lines expressing ORF4- or ORF62-encoded proteins
Schoonbroodt, Sonia; Piette, Jacques ULg; Baudoux, Laurence et al

in Journal of Medical Virology (1996), 49(4), 264-273

Varicella-Zoster virus (VZV) open reading frames 4 (ORF4) and 62 (ORF62) encode putative immediate-early proteins (ORF4p and ORF62p, respectively) which are strong transactivators of other VZV genes and ... [more ▼]

Varicella-Zoster virus (VZV) open reading frames 4 (ORF4) and 62 (ORF62) encode putative immediate-early proteins (ORF4p and ORF62p, respectively) which are strong transactivators of other VZV genes and are involved in the very early stages of viral infection. ORF4p and ORF62p transactivate immediate-early and early gene promoters but have little or no effect on late gene promoters. To investigate the effect of ORF4p or ORF62p overexpression on the viral replication cycle, we constructed Vero cell lines expressing those genes under the control of the human cytomegalovirus major immediate-early promoter. VZV OKA infection of these stably transformed cell lines was followed-up using VZV glycoprotein E (gE) antigen quantification and virus titration. Upon serial passaging of infection in these cell lines expressing functionally active ORF4p or ORF62p, a 5- to 10-fold increase in viral gE antigen production was observed. Viral titers also demonstrated a 2- to 5-fold increase in viral production in these transformed cell lines. These results emphasize the role that both ORF4p and ORF62p play in enhancing the VZV replicative cycle. (C) 1996 Wiley-Liss, Inc. [less ▲]

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See detailThe enhancers of the human placental lactogen B, A, and L genes: progressive activation during in vitro trophoblast differentiation and importance of the DF-3 element in determining their respective activities
Jacquemin, P.; Alsat, E.; Oury, Cécile ULg et al

in DNA & Cell Biology (1996), 15(10), 845-54

The hCS-A and hCS-B genes encoding human chorionic somatomammotropin and the related hCS-L gene are very similar in their coding and flanking sequences. For each of these genes, downstream enhancers ... [more ▼]

The hCS-A and hCS-B genes encoding human chorionic somatomammotropin and the related hCS-L gene are very similar in their coding and flanking sequences. For each of these genes, downstream enhancers, varying in strength, have been identified with the help of cytotrophoblast-derived JEG-3 cells, which do not express the hCS genes. Here we study the activity of the hCS enhancers in human syncytiotrophoblast in primary culture, which naturally expresses the hCS genes. We show that the activity of the hCS-B gene enhancer is mediated by two elements, DF-3 and DF-4, whereas the hCS-L and hCS-A gene enhancers display weaker activity due to mutations in their respective DF-3 sites. Replacement of the hCS-B DF-3 site with the homologous hCS-A sequence causes hCS-B enhancer activity to decrease. Primary cytotrophoblasts differentiate in culture to form the syncytiotrophoblast. We show that during this process the production of hCS progressively increases and that concomitantly all three hCS enhancers are progressively activated. A targeted mutation in the 3' part of the DF-4 element abolishes the binding of a protein present only in syncytiotrophoblast extracts and inactivates the DF-4 element. Thus, a direct correlation exists between the appearance of this syncytiotrophoblast-specific protein and hCS enhancer activity. This primary culture model proves useful in studying the regulation of the hCS genes. [less ▲]

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See detailEnhancing $l_i 3 l_j$ with the $Z^0$-penguin
Hirsch, M.; Staub, F.; Vicente, Avelino ULg

in Physical Review. D, Particles, Fields, Gravitation, and Cosmology (2012), 85

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See detailEnhancing a CH-pi interaction to increase the affinity for 5-HT1A receptors
Liégeois, Jean-François ULg; Lespagnard, Marc; Meneses Salas, Elsa et al

in ACS Medicinal Chemistry Letters (2014), 5

An electrostatic interaction related to a favourable position of the distal phenyl ring and a phenylalanine residue in the binding pocket would explain the higher 5-HT1A affinity of a 4-phenyl-1,2,3,6 ... [more ▼]

An electrostatic interaction related to a favourable position of the distal phenyl ring and a phenylalanine residue in the binding pocket would explain the higher 5-HT1A affinity of a 4-phenyl-1,2,3,6-tetrahydropyridine (THP) analogue compared to the corresponding 4-phenylpiperazine analogue. To explore a possible reinforcement of this interaction to increase the affinity for 5-HT1A receptors, different 4-substituted-phenyl analogues were synthesized and tested. The most important increase of affinity is obtained with two electron-donating methyl groups in position 3 and 5 [less ▲]

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See detailEnhancing lepton flavour violation in the supersymmetric inverse seesaw beyond the dipole contribution
Abada, Asmaa; Das, Debottam; Vicente, Avelino ULg et al

in Journal of High Energy Physics [=JHEP] (2012), 1209

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See detailEnhancing mineral segmentation in optical microscopy with multispectral imaging
Pirard, Eric ULg; De Colnet, Laurence

in Proceedings 8th European Congress for Stereology (2000)

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See detailEnhancing robustness of aerolastic instability suppression using MDOF energy sinks
Lee, Young S.; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in AIAA Journal (2008), 46(6), 1371-1394

In this last of a three paper sequence, we use simultaneous multimodal broadband targeted energy transfers to multi-degree-of-freedom nonlinear energy sinks to improve the robustness of aeroelastic ... [more ▼]

In this last of a three paper sequence, we use simultaneous multimodal broadband targeted energy transfers to multi-degree-of-freedom nonlinear energy sinks to improve the robustness of aeroelastic instability suppression of a rigid wing with structural nonlinearities. A numerical bifurcation analysis of limit cycle oscillations of the wing with the multi-degree-of-freedom nonlinear energy sinks attached shows that controlling the lower parameter value for limit point cycle bifurcation to occur above Hopf bifurcation is crucial to enhancing the robustness of limit cycle oscillation suppression. We demonstrate that multi-degree-of-freedom nonlinear energy sinks can greatly enhance the robustness of limit cycle oscillation suppression, compared with single-degree-of-freedom nonlinear energy sinks (which were studied in our previous papers), with a much smaller total mass.We also investigate the nonlinear modal interactions that occur between the aeroelastic modes and the multi-degree-of-freedom nonlinear energy sinks, in an effort to gain a physical understanding of the mechanisms governing instability suppression. We demonstrate that a properly designed multi-degree-of-freedom nonlinear energy sink provides robustness of aeroelastic instability suppression by efficiently, passively, and rapidly transferring a significant portion of unwanted vibration energy to the furthest mass of the nonlinear energy sink. Consideration of other types of multi-degree-of-freedom nonlinear energy sinks suggests that the robustness enhancement is achieved by the concentrated mass effect of the attached nonlinear energy sinks. [less ▲]

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See detailEnhancing Robustness of Instability Suppression by Means of Multi-Degree-of-Freedom Nonlinear Energy Sinks
Lee, Young S.; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Honolulu, 2007 (2007, April)

Multi-degree-of-freedom nonlinear energy sinks (MDOF NESs) are utilized to improve robustness of suppression of limit cycle oscillations (LCOs) due to aeroelastic instability. Bifurcation analysis by a ... [more ▼]

Multi-degree-of-freedom nonlinear energy sinks (MDOF NESs) are utilized to improve robustness of suppression of limit cycle oscillations (LCOs) due to aeroelastic instability. Bifurcation analysis by a numerical continuation technique shows that controlling occurrence of a limit point cycle (LPC or saddle-node) bifurcation point above a Hopf bifurcation point is crucial to enhancing robustness. Not only greatly can MDOF NESs enhance the robustness of suppression against even strong external disturbances, but they can also yield a similar e±ciency even with a smaller mass, compared to the SDOF NESs with the same parameter conditions. Nonlinear modal interactions between the aeroelastic modes and the MDOF NES are examined to demonstrate e±ciency of the MDOF NES. [less ▲]

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See detailEnhancing rural learning, linkages, and institutions: the rice videos in Africa
Van Mele, Paul; Wanvoeke, Jonas; Zossou, Enangnon ULg

in Development in Practice (2010), 20(414), 421

Africa Rice Center (WARDA) facilitated the development and translation of 11 rice videos. From 2005 to 2009, WARDA partners translated them into more than 30 African languages. Open-air video ... [more ▼]

Africa Rice Center (WARDA) facilitated the development and translation of 11 rice videos. From 2005 to 2009, WARDA partners translated them into more than 30 African languages. Open-air video presentations enhanced learning, experimentation, confidence, trust, and group cohesion among rural people. The videos strengthened capacities of more than 500 organisations and hundreds of thousands of farmers. WARDA’s integrated rural learning approach also helped women to access new markets and credit. Learning videos allow for unsupervised learning; unleash local creativity and experimentation; facilitate institutional innovations; and improve social inclusion of the poor, youth, and women. [less ▲]

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See detailEnhancing spatial estimates of metal pollutants in raw wastewater irrigated fields using a topsoil organic carbon map predicted from aerial photography
Bourennane, Hocine; Dere, Christelle ULg; Lamy, Isabelle et al

in Science of the Total Environment (2006), 361

Various approaches have been used to estimate metal pollutant element (TE) contents at unsampled locations in a 15-ha contaminated site located in the plain of Pierrelaye–Bessancourt (about 24 km ... [more ▼]

Various approaches have been used to estimate metal pollutant element (TE) contents at unsampled locations in a 15-ha contaminated site located in the plain of Pierrelaye–Bessancourt (about 24 km Northwest of Paris). 87 samples of soil plough layer were randomly sampled at each mesh of a regular square grid over the whole study area and the total contents of Cd, Cr, Cu, Ni, Pb, and Zn were measured. A first set of 50 measurements, randomly selected from the 87 samples, was used for the prediction and another set of 37 measurements was kept for the validation. Topsoil organic carbon contents (SOC) were measured at 75 sites with 50 measurements sharing the same locations as TE. An aerial photography of the study area showing bare soils was selected for relating brightness intensities and SOC. Mapping procedures used were ordinary kriging (OK), cokriging (COK), collocated cokriging (CC), and kriging with external drift (KED). SOC maps used as exhaustively sampled information in KED and CC of TE were obtained by KED and CC procedures, respectively, accounting for 75 SOC measurements and the brightness intensities of numerical counts provided by the visible bands of the aerial photograph bare soils. Consequently, for each TE, four maps were generated: two maps resulting from KED and CC procedures (KED-SOC75P, CC-SOC75P), another one provided by standard cokriging (COK-TE50SOC75) accounting for TE prediction set plus 75 SOC measurements, and the last one corresponding to that estimated by ordinary kriging from only prediction set measurements (OK50). Three indices: (1) the mean prediction error (ME) and the mean absolute prediction error (|ME|); (2) the root mean square error (RMSE); and (3) the relative improvement (RI) of accuracy, as well as residuals analysis, were computed from the validation set (observed data) and predicted values. On the 37 test data, the results showed that the more accurate predictions were systematically those obtained by kriging accounting for SOC map predicted by KED from 75 SOC measurements and brightness values of the aerial photo (KED-SOC75P) followed closely by CC-SOC75P procedure, except for Cu and Zn where CC-SOC75P appeared to be slightly more accurate than KED-SOC75P. In regard to the RI of accuracy between prediction methods, the results confirmed once for all the benefit of accounting for SOC data set plus the exhaustively sampled information provided by the aerial photography regardless of the considered TE. Nevertheless, for Cd, Pb, and Zn, the RI of accuracy was less than 20% between the two most accurate methods (KED-SOC75P and CC-SOC75P) and standard cokriging in which the information provided by the aerial photography is ignored when mapping. The sensitivity of KED-SOC75P and CC-SOC75P approaches to the sampling density of the target variables (TE) was assessed using 10 random subsets of different sizes (25 and 33 observations) drawn from a prediction set that includes 50 data. Results have shown that the TE estimates by KED-SOC75P and CC-SOC75P approaches using only 25 TE samples were much more accurate than the estimates performed by OK50 and COK-TE50SOC75 approaches that use the whole samples of the prediction set. Moreover, the RI of accuracy was reduced by less than 15% if the original sampling density was reduced by a third. [less ▲]

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See detailEnhancing temporal correlations in EOF expansions for the reconstruction of missing data using DINEOF
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Sirjacobs, Damien ULg et al

in Ocean Science (2009), 5(4), 475-485

DINEOF (Data Interpolating Empirical Orthogonal Functions) is an EOF-based technique for the reconstruction of missing data in geophysical fields, such as those produced by clouds in sea surface ... [more ▼]

DINEOF (Data Interpolating Empirical Orthogonal Functions) is an EOF-based technique for the reconstruction of missing data in geophysical fields, such as those produced by clouds in sea surface temperature satellite images. A technique to reduce spurious time variability in DINEOF reconstructions is presented. The reconstruction of these images within a long time series using DINEOF can lead to large discontinuities in the reconstruction. Filtering the temporal covariance matrix allows to reduce this spurious variability and therefore more realistic reconstructions are obtained. The approach is tested in a three years sea surface temperature data set over the Black Sea. The effect of the filter in the temporal EOFs is presented, as well as some examples of the improvement achieved with the filtering in the SST reconstruction, both compared to the DINEOF approach without filtering. [less ▲]

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See detailEnhancing The Antilisterial Effect Of Lactobacillus Curvatus Cwbi-B28 In Pork Meat And Cocultures By Limiting Bacteriocin Degradation
Kouakou, P.; Ghalfi, H.; Destain, Jacqueline ULg et al

in Meat Science (2008), 80(3),

This work focused on Listeria monocytogenes growth inhibition and growth rebound in raw and cooked pork meat inoculated with Lactobacillus curvatus strains. During storage of raw meat homogenates in the ... [more ▼]

This work focused on Listeria monocytogenes growth inhibition and growth rebound in raw and cooked pork meat inoculated with Lactobacillus curvatus strains. During storage of raw meat homogenates in the presence of the bacteriocin-producing strain Lactobacillus curvatus CWBI-B28wt, the Listeria monocytogenes cfu count was initially reduced to an undetectable level, but a growth rebound occurred after two weeks, coinciding with loss of 70% of the bacteriocin activity present at the end of week 2. The Listeria growth rebound was suppressed when proteolysis of bacteriocin was countered by the absence of proteases (bacteriocin addition to cooked meat) or the presence of 1% soy flour (added to provide competing substrates). Further experiments confirmed that bacteriocin is sensitive to the action of proteolytic enzymes isolated from both Lactobacillus curvatus CWBI-B28wt and the meat matrix. Bacteriocin proteolysis thus emerges as a cause of Listeria growth rebound. [less ▲]

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See detailEnhancing the salience of fluency improves recognition memory performance in mild Alzheimer’s disease
Bastin, Christine ULg; Willems, Sylvie ULg; Genon, Sarah ULg et al

in Journal of Alzheimer's Disease [=JAD] (2013), 33

Recognition memory can rely on recollection (recall of the details from the encoding episode) and familiarity (feeling that some information is old without any recollection). In Alzheimer’s disease (AD ... [more ▼]

Recognition memory can rely on recollection (recall of the details from the encoding episode) and familiarity (feeling that some information is old without any recollection). In Alzheimer’s disease (AD), whereas there is a clear deficit of recollection, the evidence regarding familiarity is mixed, with some studies showing preserved familiarity and others reporting impairment. The current study examined whether recognition memory performance can be improved in AD when the use of familiarity is facilitated by the salience of processing fluency due to an earlier encounter with the information. Fifteen AD patients and 16 healthy controls performed a verbal recognition memory task where the salience of fluency was manipulated by means of letters overlap. Studied and unstudied words were constituted of either two separate sets of letters (no-overlap condition, high fluency salience) or the same set of letters (overlap condition, low fluency salience). The results showed that, although performance was globally poorer in AD patients than in the controls, both groups performed significantly better in the no-overlap condition than in the overlap condition. This suggests that AD patients benefited as much as the controls from the salience of fluency. [less ▲]

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