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See detailImpact of growth hormone (GH) deficiency and GH replacement upon thymus function in adult patients.
Morrhaye, Gabriel ULg; Kermani, Hamid; Legros, Jean-Jacques ULg et al

in PLoS ONE (2009), 4(5), 5668

BACKGROUND: Despite age-related adipose involution, T cell generation in the thymus (thymopoiesis) is maintained beyond puberty in adults. In rodents, growth hormone (GH), insulin-like growth factor-1 ... [more ▼]

BACKGROUND: Despite age-related adipose involution, T cell generation in the thymus (thymopoiesis) is maintained beyond puberty in adults. In rodents, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and GH secretagogues reverse age-related changes in thymus cytoarchitecture and increase thymopoiesis. GH administration also enhances thymic mass and function in HIV-infected patients. Until now, thymic function has not been investigated in adult GH deficiency (AGHD). The objective of this clinical study was to evaluate thymic function in AGHD, as well as the repercussion upon thymopoiesis of GH treatment for restoration of GH/IGF-1 physiological levels. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-two patients with documented AGHD were enrolled in this study. The following parameters were measured: plasma IGF-1 concentrations, signal-joint T-cell receptor excision circle (sjTREC) frequency, and sj/beta TREC ratio. Analyses were performed at three time points: firstly on GH treatment at maintenance dose, secondly one month after GH withdrawal, and thirdly one month after GH resumption. After 1-month interruption of GH treatment, both plasma IGF-1 concentrations and sjTREC frequency were decreased (p<0.001). Decreases in IGF-1 and sjTREC levels were correlated (r = 0.61, p<0.01). There was also a decrease in intrathymic T cell proliferation as indicated by the reduced sj/beta TREC ratio (p<0.01). One month after reintroduction of GH treatment, IGF-1 concentration and sjTREC frequency regained a level equivalent to the one before GH withdrawal. The sj/beta TREC ratio also increased with GH resumption, but did not return to the level measured before GH withdrawal. CONCLUSIONS: In patients with AGHD under GH treatment, GH withdrawal decreases thymic T cell output, as well as intrathymic T cell proliferation. These parameters of thymus function are completely or partially restored one month after GH resumption. These data indicate that the functional integrity of the somatotrope GH/IGF-1 axis is important for the maintenance of a normal thymus function in human adults. TRIAL REGISTRATION: ClinicalTrials.gov NTC00601419. [less ▲]

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See detailImpact of growth rate on the distribution of visually strength-graded West-European Douglas-fir boards
Henin, Jean-Marc; Hebert, Jacques ULg; Jourez, Benoît ULg

Poster (2013, October)

Douglas-fir is a relatively new species within the forest landscape of Wallonia (Southern Belgium). Consequently, some uncertainties remain regarding how to keep full advantage of its high productivity as ... [more ▼]

Douglas-fir is a relatively new species within the forest landscape of Wallonia (Southern Belgium). Consequently, some uncertainties remain regarding how to keep full advantage of its high productivity as well as of the good properties of its wood. Moreover, the recent implementation of the timber strength grading (Council Directive 89/106/EEC) is likely to sensitize forest managers and the sawing industry to the impact of sylviculture on the resource quality. In that context, this research aimed at assessing to what extent the ring width of the trees (RWtree) and the mean girth increment of the stands (MGI) influences, in the frame of a visual strength grading, the distribution of the boards they produce. The experimental material was derived from 33 trees (girth range of between 120cm and 170cm) originating from 11 Douglas-fir stands (age range of between 41 and 69 y.o.) representative of contrasting sylvicultural management practices: RWtree ranged from 3 to 6 mm. From a bolt located 6 to 8.2m height in the standing trees, boards (38X100X2100mm³) were sawn and graded according to the Belgian Standard NBN B 16-520. This research evidenced that: - Only the Knot Area Ratio (KAR) impedes boards to be employed in structural uses. Practically, no board having a KAR allowing S10 grading (S10 corresponds to C30 as defined in EN338) exhibits a ring width higher than 6mm, which is the maximum value accepted for S10 grading (according to NBN B 16-520). These observations demonstrate the highly prevailing character of the knottiness regarding the boards’ grading; - 87% of the boards produced by trees from RWtree≥5mm can be used in structural uses, but only 7% can be classified into S10 strength class. In comparison, trees with RWtree<4.5mm also provided 87% of boards which can be used in structure, but 18% of the boards can be graded into S10 strength class; - 89% of the boards produced by stands with MGI>3cm/year are accepted for structural uses, but only 9% are graded into S10 class. Regarding the stands with MGI≤3cm/year, these values are 89% and 24%, respectively. Growth rate thus doesn’t seem to affect the percentage of Douglas-fir boards fit for structural uses. Dynamic sylviculture however significantly decreases the percentage of boards graded into S10 strength class: although it should be supported by financial assessments, early pruning thus seems highly advisable in a context of dynamic sylviculture. [less ▲]

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See detailImpact of growth rate on the mechanical properties of Douglas-fir grown in Wallonia (Southern Belgium)
Pollet, Caroline; Henin, Jean-Marc; Jourez, Benoît ULg et al

Poster (2013, October)

Timber is traditionally the main purpose of Douglas-fir in Europe. However, some uncertainties remain concerning the sylviculture that should be applied in order to maximise girth growth rate (GR) without ... [more ▼]

Timber is traditionally the main purpose of Douglas-fir in Europe. However, some uncertainties remain concerning the sylviculture that should be applied in order to maximise girth growth rate (GR) without affecting the good mechanical properties of the wood. So, the present study aimed at assessing to what extent the GR of Douglas-firs grown in Wallonia influences the mechanical properties of wood clear samples. The modulus of elasticity (E) and static bending strength (σf) were measured according to NF B51-016 and NF B51-008 and are discussed according to the ring width measured on the samples, as well as on the growth rate of the trees and of the stands, for both juvenile and mature wood. This assessment will help to provide sylviculture guidelines for foresters. The experimental material was derived from 11 Douglas-fir stands distributed all over Wallonia, Southern Belgium. At the time of felling, the age of the stands ranged from 41 to 69 years old. In each stand, six trees were felled, their girth varying from 120cm to 179 cm. As a consequence of the sampling methodology the growth rate of the trees ranged from 3 mm to 7 mm. From the 66 butt logs, 274 and 884 clear samples were taken in the juvenile and mature wood respectively. This research evidenced that: - Whatever the GR, the mean values of E and σf in the juvenile wood are 20% lower than those in the mature wood; - At the tree level, the mean E and σf of the samples taken from trees with ring width>5mm are about 10% lower than those of the samples taken from trees with ring width<5mm, whether considering juvenile or mature wood; - At the stand level and regardless to the type of wood (juvenile/mature), the mean E and σf of the samples originating from stands with mean girth increment>3cm/year are respectively 5% and 9% lower than those of the samples originating from stands with mean girth increment <3cm/year. This observation should lead the forest manager to consider carefully sylvicultural practices that would induce a too fast juvenile growth; high growth rate in the mature wood do not appear to be a problem considering the properties studied here. One should however take into account the impact of the growth rate on the singularities of the boards. [less ▲]

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See detailThe impact of HAART initiation on the selection and persistence of HIV-1 CTL-escape mutations
Dilernia, D.A.; Monaco, D.C.; Jones, L.R. et al

in AIDS Research and Human Retroviruses (2010, October), 26(10), 72

The impact of HAART initiation on the selection and persistence of HIV-1 CTL-escape mutations D.A. Dilernia,1 D.C. Monaco,1 L.R. Jones,2 G.D. Damilano,1 S. Rodriguez,3 H. Salomon1 1Argentinean Reference ... [more ▼]

The impact of HAART initiation on the selection and persistence of HIV-1 CTL-escape mutations D.A. Dilernia,1 D.C. Monaco,1 L.R. Jones,2 G.D. Damilano,1 S. Rodriguez,3 H. Salomon1 1Argentinean Reference Center for AIDS, Capital Federal, Argentina; 2División de Biología Molecular, Estación de Fotobiología, Playa Unión, Rawson, Chubut, Argentina; 3INTA, Castelar, Buenos Aires, Argentina Background: Immune response drives the selection of CTL escape mutations during the course of HIV infection. After initiation of HAART, antiviral drugs exert a strong selective force leading to an important limitation of viral replication. Our objective was to evaluate the impact of HAART initiation on the selection and persistence of CTL-escape mutations. Methods: Blood samples were collected from 113 newly HIV diagnosed individuals. A second sample was collected from 49 of them after 3 years. (12 of which were still drug-naı¨ve in the second sample). Dynamics of CTL-escape mutations identified in the gag gene by statistical analysis of HLA genes and viral sequences, including multiple comparison corrections (BH method) and phylogeny correction (Bayesian MCM method), were analyzed. Epitope-specific immune response was evaluated by ELISPOT against sequence-based designed peptides. Results: Immune response was evaluated on 113 individuals on an HLA-allele basis. Positive responses were detected against 6 of the 9 epitopes containing HLA-associated CTL-escape mutations.A03-restricted epitope RLRPGGKKK had the highest frequency of detection in allele-matched individuals (75%). Epitopes harboring the CTL-escape mutations identified through negative associations (i.e. escape is consensus) had lower frequency of detection: A02-restricted SLYNTVATL(25%) and A24-resctricted KYKLKHIVW(0%). Epitope sequences analysis over the second sample of 21 patients successfully sequenced showed that 38% of them did not have evidence of escape neither in the first sample nor in the second, 44% had the escape mutations in both samples and in 18%the escape mutations appeared in the second sample. Of the 7 individuals containing the epitopes of the last group, only 2 had initiated HAART (28.6%) while 64.3% (9/14) of individuals where no escape emerged, had initiated HAART. Conclusion: Accumulation of CTL-escape mutations at the population-level impaired recognition by individuals studied while initiation of HAART may prevent the selection of new escape mutations even in advanced stages of infection. [less ▲]

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See detailImpact of Harmonia axyridis (Coleoptera: Coccinellidae) on the survival rates of other aphidophagous species in semi-field conditions
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

in Communications in Agricultural and Applied Biological Sciences (2011, May 24), 76(2), 219-226

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild ... [more ▼]

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild predator, consuming other aphid natural enemies. Interactions between this exotic ladybird and other aphidophagous species present in Belgian agro-ecosystems such as Coccinella septempunctata, Episyrphus balteatus and Chrysoperla carnea are asymmetric to the benefit of H. axyridis. This study focuses on the survival rate of three aphidophagous species Harmonia axyridis (Ha), Coccinella septempunctata (C7) and Episyrphus balteatus (Eb) placed in cages in biological fields of potato and sugar beet. During June and July, hermetic cages were disposed on the crops with 10 larvae (second stage) of each aphidophagous. Four types of cages were observed (1) Ha+Eb+C7+ aphids, (2) Ha+Eb+C7, (3) Eb+C7+ aphids and (4) Eb+C7. Each combination was repeated three times. In sugar beet fields, E. balteatus was the species with the highest mortality rate. The two coccinellid species had a better survival rate than E. balteatus. All aphidophagous species had higher mortality rates in absence of aphids. In potato, when aphids were present in excess, the survival rates of all aphidophagous insects were lower than in sugar beet probably because A. fabae is less adapted to the potato morphology. Nevertheless, we have observed in potato no mortality of C. 7-punctata during all its development cycle. This suggests that (1) C. 7-punctata may use aphids as food sources more efficiently than H. axyridis and (2) that interactions between aphidophagous could be less frequent (difficulty of mobility). In potato and sugar beet, H. axyridis had the longest development cycle, being still at the larval stage when C. 7-punctata and E. balteatus reached the pupae stage. We can suppose that pupae of E. balteatus and C. 7-punctata were an alternative food (intraguild prey) to H. axyridis when aphids were lacking. Pupae are immobile and therefore more sensitive to the attack of predators. [less ▲]

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See detailImpact of health professionals utilization induced by musculoskeletal disorders among active subjects
Rabenda, Véronique ULg; Manette, Christelle; Lemmens, Régine et al

in Osteoporosis International (2005, March), 16(Suppl.3), 110

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See detailIMPACT OF HEAVY METALS ON PHYSIOLOGICAL AND PROTEOMIC RESPONSES OF WILLOWS (SALIX SP.)
Evlard, Aricia ULg; Sergeant, Kjell; Ferrandis, Salvador et al

Poster (2012)

In 2010, around 3,800 sites in Wallonia (Belgium) were identified as potentially contaminated by heavy metals, a result of their past industrial and agricultural activities [1]. The technique of using ... [more ▼]

In 2010, around 3,800 sites in Wallonia (Belgium) were identified as potentially contaminated by heavy metals, a result of their past industrial and agricultural activities [1]. The technique of using plants to remediate contaminated sites (phytoremediation) has been studied for over twenty years. In particular, the use of trees (alder, willow, poplar) has been considered because of their large biomass production [2] [3] [4] [5]. The aim of this study was to identify the potential of local willow ecotypes to grow in the presence of heavy metals using lysimeters filled with dredging sludge. Several willow ecotypes were compared realizing morphological and physiological measurements (chlorophyll fluorescence, electrolyte leakage, carbohydrate content). The plant responses to metal stress were also investigated using a proteomic approach. Heavy metals contents in leaves and stems were analysed. With this study, the potential of these trees to valorise contaminated, abandoned sites in Belgium was evaluated. [1] Cellule Etat de l'environnement wallon (2010). Tableau de bord de l'environnement wallon. SPW-DGARNE-DEMNA-DEE. [2] Dickinson N. M. (2000). Strategies for sustainable woodland on contaminated soils. Chemosphere 41(1-2): 259-263. [3] Meers E., Lamsal S., Vervaeke P., Hopgood M., Lust N. and Tack F. M. G. (2005). Availability of heavy metals for uptake by Salix viminalis on a moderately contaminated dredged sediment disposal site. Environ Pollut 137(2): 354-364. [4] Meers E., Vandecasteele B., Ruttens A., Vangronsveld J. and Tack F. M. G. (2007). Potential of five willow species (Salix spp.) for phytoextraction of heavy metals. Environ Exp Bot 60(1): 57-68. [5] Rosselli W., Keller C. and Boschi K. (2003). Phytoextraction capacity of trees growing on a metal contaminated soil. Plant Soil 256(2): 265-272. [less ▲]

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See detailImpact of helium diffusion and helium-flash-induced carbon production on gravity-mode pulsations in subdwarf B stars
Hu, Haili; Nelemans, G.; Aerts, C. et al

in Astronomy and Astrophysics (2009), 508

Context: Realistic stellar models are essential to the forward modelling approach in asteroseismology. For practicality however, certain model assumptions are also required. For example, in the case of ... [more ▼]

Context: Realistic stellar models are essential to the forward modelling approach in asteroseismology. For practicality however, certain model assumptions are also required. For example, in the case of subdwarf B stars, one usually starts with zero-age horizontal branch structures without following the progenitor evolution. <BR /> Aims: We analyse the effects of common assumptions in subdwarf B models on the g-mode pulsational properties. We investigate if and how the pulsation periods are affected by the H-profile in the core-envelope transition zone. Furthermore, the effects of C-production and convective mixing during the core helium flash are evaluated. Finally, we reanalyse the effects of stellar opacities on the mode excitation in subdwarf B stars.<BR /> Methods: We computed detailed stellar evolutionary models of subdwarf B stars, and their non-adiabatic pulsational properties. Atomic diffusion of H and He is included consistently during the evolution calculations. The number fractions of Fe and Ni are gradually increased by up to a factor of 10 around log T = 5.3. This is necessary for mode excitation and to approximate the resulting effects of radiative levitation. We performed a pulsational stability analysis on a grid of subdwarf B models constructed with OPAL and OP opacities.<BR /> Results: We find that helium settling causes a shift in the theoretical blue edge of the g-mode instability domain to higher effective temperatures. This results in a closer match to the observed instability strip of long-period sdB pulsators, particularly for l â ¤ 3 modes. We show further that the g-mode spectrum is extremely sensitive to the H-profile in the core-envelope transition zone. If atomic diffusion is efficient, details of the initial shape of the profile become less important in the course of evolution. Diffusion broadens the chemical gradients, and results in less effective mode trapping and different pulsation periods. Furthermore, we report on the possible consequences of the He-flash for the g-modes. The outer edge of a flash-induced convective region introduces an additional chemical transition in the stellar models, and the corresponding spike in the Brünt-Väisälä frequency produces a complicated mode trapping signature in the period spacings. <BR /> [less ▲]

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See detailImpact of hemodynamic load on exercise capacity in aortic stenosis
Dulgheru, Raluca Elena ULg; Magne, Julien ULg; Capoulade, R et al

in International Journal of Cardiology (2013)

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See detailImpact of heterogeneity on estimation of infectious disease parameters
Cattaert, Tom ULg

Master's dissertation (2008)

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See detailThe Impact of Higher Order Differentiability and Auxiliary Slave Nodes in Two-dimensional Contact Elements
Nguyen, Duc Tue ULg; Gaston, Rauchs; Jean Philippe, Ponthot

Scientific conference (2011, November 14)

The aim of this work is to propose new contact elements of higher order of differentiability for analysing twodimensional frictionless contact problems. Several methods were proposed in the literature to ... [more ▼]

The aim of this work is to propose new contact elements of higher order of differentiability for analysing twodimensional frictionless contact problems. Several methods were proposed in the literature to solve the problem caused by the lack of continuity resulting from the discretization. Among them are Bézier interpolation, Hermitian interpolation and splines. One of the difficulties in using Hermitian interpolation is to verify the partition of unity. Therefore, new elements that satisfy the C1 and C2 continuity at the interface are presented in this paper. These new contact elements are based on Hermitian polynomials for ensuring a higher order of continuity. The advantage is that this approach can be easily developed not only for linear elements but also for quadratic elements with higher order of differentiability. The performance of different surface representations is assessed through a comparison with a C0 surface discretization. Some numerical examples are used for assessing the accuracy and the convergence behaviour. [less ▲]

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See detailImpact of hydroelectric power releases on the morphology and the sedimentology of the bed of the Warche River (Belgium).
Assani, A. A.; Petit, François ULg

in Earth Surface Processes & Landforms (2004)

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See detailThe Impact of Illiquidity and Higher Moments of Hedge Fund Returns on Their Risk-Adjusted Performance and Diversification Potential
Cavenaile, Laurent ULg; Coen, Alain; Hübner, Georges ULg

in Journal of Alternative Investments (2011), 13(4),

This paper studies the joint impact of smoothing and fat tails on the risk-return properties of hedge fund strategies. First, we adjust risk and performance measures for illiquidity and the non-Gaussian ... [more ▼]

This paper studies the joint impact of smoothing and fat tails on the risk-return properties of hedge fund strategies. First, we adjust risk and performance measures for illiquidity and the non-Gaussian distribution of hedge funds returns. We use two risk metrics: the Modified Value-at-Risk and a preference-based measure retrieved from the linear-exponential utility function. Second, we revisit the hedge fund diversification effect with these adjustments for illiquidity. Our results report similar fund performance rankings and optimal hedge fund strategy allocations for both adjusted metrics. We also show that the benefits of hedge funds in portfolio diversification are still persistent but tend to weaken after the adjustment for illiquidity. [less ▲]

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See detailImpact of Imatinib on immune function in vitro
Pirson, Laurence ULg; Baron, Frédéric ULg; Gothot, André ULg et al

Poster (2006)

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See detailImpact of implant geometry and loading on early bone formation, Clinical Oral Implants Research
Vandamme, Katleen; Naert, Ignace; Geris, Liesbet ULg et al

in Clinical Oral Implants Research (2007), 18(5), 71-72

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See detailImpact of in vivo T-cell depletion on outcome of AML patients in first CR given peripheral blood stem cells and reduced-intensity conditioning all-SCT from a HLA-identical sibling donor : a report from the Acute Leukemia Working Party of the European group for Blood and Marrow Transplantation
Baron, Frédéric ULg; Labopin, M.; Blaise, D. et al

in Bone Marrow Transplantation (2014)

The impact of in vivo T-cell depletion on transplantation outcomes in patients transplanted with reduced-intensity conditioning (RIC) remains controversial. This study assessed the outcome of 1250 adult ... [more ▼]

The impact of in vivo T-cell depletion on transplantation outcomes in patients transplanted with reduced-intensity conditioning (RIC) remains controversial. This study assessed the outcome of 1250 adult patients with de novo AML in first CR (CR1) given PBSC from HLA-identical siblings after chemotherapy-based RIC. A total of 554 patients did not receive any form of in vivo T-cell depletion (control group), whereas antithymocyte globulin (ATG) and alemtuzumab were given in 444 and 252 patients, respectively. The incidences of grade II-IV acute GVHD were 21.4, 17.6 and 10.2% in control, ATG and alemtuzumab patients, respectively (Po0.001). In multivariate analysis, the use of ATG and the use of alemtuzumab were each associated with a lower risk of chronic GVHD (Po0.001 each), but a similar risk of relapse, and of nonrelapse mortality, and similar leukemia-free survival and OS. Further, among patients given BU-based RIC, the use of o6 mg/kg ATG did not increase the risk of relapse (hazard ratio, HR¼1.1), whereas there was a suggestion for higher relapse risk in patients given X6 mg/kg ATG (HR¼1.4, P¼0.08). In summary, these data suggest that a certain amount of in vivo T-cell depletion can be safely used in the conditioning of AML patients in CR1 given PBSC after chemotherapy-based RIC. [less ▲]

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See detailThe impact of industrialization upon rural – urban relations in Vietnam
Nguyen Thi, Dien; Lebailly, Philippe ULg; Vu Dinh, Ton

Scientific conference (2013)

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See detailThe impact of infliximab therapy on colonic mucosal expression of barrier genes in patients with inflammatory bowel disease
Arijs, I.; Quintens, R.; Van Lommel, L. et al

in Gastroenterology (2009), 136

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See detailThe impact of infliximab therapy on colonic mucosal expression of barrier genes in patients with inflammatory bowel disease.
Arijs, I.; Quintens, R.; Van Lommel, L. et al

in Acta Gastro-Enterologica Belgica (2009)

Detailed reference viewed: 7 (3 ULg)