Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailCombined implicit-explicit algorithms for non-linear structural dynamics
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg et al

in Revue Européenne des Éléments Finis (2002), 11(5), 565-591

To solve fast dynamic problems, an explicit method is the most adapted. But for slower dynamics, an implicit method is more stable. The industrial problems are governed by high frequency (impact ... [more ▼]

To solve fast dynamic problems, an explicit method is the most adapted. But for slower dynamics, an implicit method is more stable. The industrial problems are governed by high frequency (impact, ...) during short time intervals and slower dynamics (spring-back, ...) during other time intervals. The optimal solution is then to have both implicit algorithm and explicit methods readily available in the same code and to be able to switch automatically from one to another. Criteria that decide when to shift from a method to another have been developed here. Implicit balanced restarting conditions that annihilate numerical oscillations resulting for an explicit calculation are also proposed. [less ▲]

Detailed reference viewed: 73 (8 ULg)
Full Text
Peer Reviewed
See detailCombined implicit/explicit algorithms for crashworthiness analysis
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in International Journal of Impact Engineering (2004), 30(8-9, SEP-OCT), 1161-1177

In order to simulate an industrial process, an explicit method, which is conditionally stable, is the most adapted while the non-linearities evolve rapidly (impact phase, stamping process, etc.). But when ... [more ▼]

In order to simulate an industrial process, an explicit method, which is conditionally stable, is the most adapted while the non-linearities evolve rapidly (impact phase, stamping process, etc.). But when the dynamics becomes quasi-linear (post-impact analysis, springback simulation, etc.), an implicit method, which is iterative, presents the advantage of unconditional stability. The optimal solution is then to have both implicit and explicit methods readily available in the same code and to be able to switch automatically from one to the other. Criteria that decide to switch from one method to another, depending on the current dynamics, have been developed. Implicit restarting conditions are also proposed that annihilate numerical oscillations resulting from an explicit calculation. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 38 (3 ULg)
See detailCombined implicit/explicit time integration algorithms for crashworthiness analysis and metal forming simulation
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Proceedings of IMPLAST'2003, 8th International Symposium on Plasticity and Impact Mechanics (2003, March)

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailCombined implicit/explicit time-integration algorithms for the numerical simulation of sheet metal forming
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Journal of Computational & Applied Mathematics (2004), 168(1-2, Sp. Iss. SI), 331-339

In order to simulate stamping processes, an explicit method, which is conditionally stable, is generally thought to be the most adapted. Such an algorithm presents the advantage of being noniterative ... [more ▼]

In order to simulate stamping processes, an explicit method, which is conditionally stable, is generally thought to be the most adapted. Such an algorithm presents the advantage of being noniterative while, the contact configuration evolves rapidly, and the conditional stability is not a disadvantage since time steps must be small enough anyway for an accurate computation. But during the springback simulation, an implicit method, which is iterative, presents the advantage of unconditional stability. The optimal solution is then to have both implicit and explicit methods readily available in the same code and to be able to switch automatically from one to the other. Criteria that decide to switch from a method to another, depending on the current dynamic, have been developed. Implicit restarting conditions are also proposed that annihilate numerical oscillations resulting from an explicit calculation. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 54 (4 ULg)
Full Text
Peer Reviewed
See detailA combined incremental-secant mean-field homogenization scheme with per-phase residual strains for elasto-plastic composites
Wu, Ling ULg; Noels, Ludovic ULg; Adam, Laurent et al

in International Journal of Plasticity (2013), 51

This paper presents an incremental secant mean-fi eld homogenization (MFH) procedure for composites made of elasto-plastic constituents. In this formulation, the residual stress and strain states reached ... [more ▼]

This paper presents an incremental secant mean-fi eld homogenization (MFH) procedure for composites made of elasto-plastic constituents. In this formulation, the residual stress and strain states reached in the elasto-plastic phases upon a fi ctitious elastic unloading are considered as starting point to apply the secant method. The mean stress fields in the phases are then computed using secant tensors, which are naturally isotropic and enable to de fine the Linear-Comparison-Composite. The method, which remains simple in its formulation, is valid for general non-monotonic and non-proportional loading. It is applied on various problems involving elastic, elasto-plastic and perfectly-plastic phases, to demonstrate its accuracy compared to other existing MFH methods. [less ▲]

Detailed reference viewed: 125 (64 ULg)
Full Text
Peer Reviewed
See detailCombined Interferon-Gamma and Tumor Necrosis Factor-Alpha Treatment Differentially Affects Adhesion and Migration of Keratinocyte-Derived Cells to Laminin-1
van den Brule, Frédéric A; Clausse, Nathalie; Delvenne, Philippe ULg et al

in Cell Adhesion and Communication (2000), 7(4), 321-9

Interactions with the extracellular matrix constitute basic steps in cervix carcinoma cell invasion. In this study, we examined the adhesion and migration profiles of two human papillomavirus (HPV) DNA ... [more ▼]

Interactions with the extracellular matrix constitute basic steps in cervix carcinoma cell invasion. In this study, we examined the adhesion and migration profiles of two human papillomavirus (HPV) DNA-transfected keratinocyte-derived cell lines, EIL8 and 18-11S3, and of the cervix adenocarcinoma SiHa cell line, towards laminin-1, and the selective effect of a 24-72 h treatment of 1000 U/ml interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), a treatment that significantly decreases cervix carcinoma cell proliferation and progression in nude mice, on these parameters. Compared to normal cervix keratinocytes (CK) and two HPV DNA-transfected keratinocyte cell lines, in basal conditions, the SiHa cell line was characterized by increased attachment (SiHa, 48.74 +/- 4.02 vs. normal keratinocytes, 4.32 +/- 0.40, EIL8, 17.80 +/- 3.03 and 18-11S3, 17.82 +/- 1.48% of attached cells after 30 min) and marked directed chemotactic migration towards laminin-1. Interestingly, treatment of the cells with the cytokines (1000 U/ml IFN-gamma and TNF-alpha) did not modulate the adhesion properties of the cells, but chemotactic migration of SiHa cells to laminin-1 was significantly decreased, while migration towards type I collagen was increased. Similar results were obtained with the Ca Ski cervix carcinoma cell line. Our results emphasize the altered pattern of interactions of cervix carcinoma cells with extracellular matrix components such as laminin-1, compared to normal and pre-neoplastic cells, and contributes to the understanding of the effects of cytokine treatment on cervix carcinoma cells. [less ▲]

Detailed reference viewed: 26 (5 ULg)
Full Text
Peer Reviewed
See detailCombined Intra- and Inter-domain Traffic Engineering using Hot-Potato Aware Link Weights Optimization
Balon, Simon ULg; Leduc, Guy ULg

in ACM SIGMETRICS Performance Evaluation Review (2008), 36(1), 441-442

A well-known approach to intradomain traffic engineering consists in finding the set of link weights that minimizes a network-wide objective function for a given intradomain traffic matrix. This approach ... [more ▼]

A well-known approach to intradomain traffic engineering consists in finding the set of link weights that minimizes a network-wide objective function for a given intradomain traffic matrix. This approach is inadequate because it ignores a potential impact on interdomain routing due to hot-potato routing policies. This may result in changes in the intradomain traffic matrix that have not been anticipated by the link weights optimizer, possibly leading to degraded network performance. <br /> <br />We propose a BGP-aware link weights optimization method that takes these hot-potato effects into account. This method uses the interdomain traffic matrix and other available BGP data, to extend the intradomain topology with external virtual nodes and links, on which all the well-tuned heuristics of a classical link weights optimizer can be applied. Our method can also optimize the traffic on the interdomain peering links. [less ▲]

Detailed reference viewed: 54 (10 ULg)
Peer Reviewed
See detailCombined Liver - Spleen -small intestine grafting in a rat model: Role of transplanting additional lymphoid tissue on survival.
D'Silva, Milbhor; Pirenne, Jacques; Nakhleh, R. E. et al

in International Surgery (1996), (81), 109-114

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailCombined locked nucleic acid and molecular beacon technologies for sensitive detection of the JAK2(V617F) somatic single-base sequence variant
Sidon, P.; Heimann, P.; Lambert, Frédéric ULg et al

in Clinical Chemistry (2006), 52(7), 1436-1438

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailCombined metabolomic and genetic approaches reveal a link between the polyamine pathway and albumin 2 in developing pea seeds.
Vigeolas, Hélène ULg; Chinoy, Catherine; Zuther, Ellen et al

in Plant Physiology (2008), 146(1), 74-82

Several legume seed proteins that are potentially allergenic, poorly digested by farm animals, and/or have undesirable functional properties, have been described. One of these is the albumin protein in ... [more ▼]

Several legume seed proteins that are potentially allergenic, poorly digested by farm animals, and/or have undesirable functional properties, have been described. One of these is the albumin protein in pea (Pisum sativum) called PA2. A naturally occurring mutant line that lacks PA2 has been exploited in studies to determine the biological function of this nonstorage protein in seed development. The mutant, which has a small seed, a tall plant phenotype, and lacks most of the PA2-encoding genes, has been crossed with a standard cultivar, 'Birte,' which contains PA2 to give rise to a recombinant inbred (RI) population. An F(3) line carrying the mutation and having a short plant phenotype has been used to generate backcross (BC) lines with 'Birte.' Despite having a lower albumin content, seeds from the mutant parent and RI lines lacking PA2 have an equivalent or higher seed nitrogen content. Metabolite profiling of seeds revealed major differences in amino acid composition and polyamine content in the two parent lines. This was investigated further in BC lines, where the effects of differences in seed size and plant height between the two parents were eliminated. Here, differences in polyamine synthesis were maintained as was a difference in total seed protein between the BC line lacking PA2 and 'Birte.' Analysis of enzyme activities in the pathways of polyamine synthesis revealed that the differences in spermidine content were attributable to changes in the overall activities of spermidine synthase and arginine decarboxylase. Although the genes encoding spermidine synthase and PA2 both localized to the pea linkage group I, the two loci were shown not to be closely linked and to have recombined in the BC lines. A distinct locus on linkage group III contains a gene that is related to PA2 but expressed predominantly in flowers. The results provide evidence for a role of PA2 in regulating polyamine metabolism, which has important functions in development, metabolism, and stress responses in plants. [less ▲]

Detailed reference viewed: 20 (4 ULg)
Full Text
See detailCombined method for the sequential measurement of (1) the enzymatically active fraction and (2) the total amount of an enzyme
Serteyn, Didier ULg; Deby-Dupont, Ginette; Franck, Thierry ULg et al

Patent (2009)

The present invention is related to a combined method and kit (or device) for the sequential measurement of the enzymatically active fraction and the total amount of an enzyme [(such as myeloperoxidase ... [more ▼]

The present invention is related to a combined method and kit (or device) for the sequential measurement of the enzymatically active fraction and the total amount of an enzyme [(such as myeloperoxidase (MPO)] in a sample, and that find improved applications in veterinary and human health fields. [less ▲]

Detailed reference viewed: 12 (1 ULg)
Peer Reviewed
See detailCombined mexiletine and amiodarone treatment of refractory recurrent ventricular tachycardia.
Waleffe, A.; Mary-Rabine, L.; Legrand, Victor ULg et al

in American heart journal (1980), 100(6 Pt 1), 788-93

A combined mexiletine and amiodarone treatment was applied in nine cases with recurrent refractory ventricular tachycardia. During the first two days of treatment, mexiletine and amiodarone were perfused ... [more ▼]

A combined mexiletine and amiodarone treatment was applied in nine cases with recurrent refractory ventricular tachycardia. During the first two days of treatment, mexiletine and amiodarone were perfused intravenously at a dose of 1,000 mg. and 1,500 mg. per 24 hours, respectively. Simultaneously amiodarone was also given orally at a dose of 600 mg. per 24 hours. From the third day onwards, the intravenous administration was interrupted and both drugs were continued orally at a dose of 600 mg. daily. The first three patients were very critically ill and had had at least five episodes of ventricular tachycardia per 24 hours during the last 10 days in the intensive care unit. The treatment resulted in total suppression of the tachycardic episodes within three days after initiation of therapy. In the remaining six cases, ventricular tachycardia was easily initiated by programmed electrical stimulation of the heart. No arrhythmia could be elicited by repeated testing on the seventh day of treatment. The mean follow-up period was 6 months. Two patients with poor left ventricular function died in intractable heart failure. Another one died suddenly 4-1/2 months after his release from the hospital. He had a large aneurysm and whether he continued his treatment is unknown. A fourth patient had an aneurysmectomy; he suffered a recurrence, and died at his second operation. All the others presently remain asymptomatic. The association of a class I (mexiletine) with a class III (amiodarone) agent is theoretically attractive for the treatment of refractory ventricular arrhythmias. The present findings corroborate this hypothesis, but show that this association is not able to protect individuals with severe underlying myocardial damage. [less ▲]

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailCombined micro-Fourier transform infrared (FTIR) spectroscopy and micro-Raman spectroscopy of Proterozoic acritarchs: A new approach to Palaeobiology
Marshall, C. P.; Javaux, Emmanuelle ULg; Knoll, A. H. et al

in Precambrian Research (2005), 138(3-4), 208-224

Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their ... [more ▼]

Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their biological affinities. A combination of micro-Fourier transform infrared (FTIR) spectroscopy and laser micro-Raman spectroscopy was used to investigate the organic structure and composition of individual acritarchs. Well preserved Neoproterozoic acritarchs from the Tanana Formation, Australia (ca. 590-565 Ma), and Mesoproterozoic acritarchs from the Roper Group (1.5-1.4 Ga), Australia, and Ruyang Group, China (1.4-1.3 Ga, age poorly resolved but certainly > 1000 Ma and < 1625 Ma) have thermal maturities that range from immature to oil window. FTIR spectra of Tanarium conoideum from the Tanana Formation contain intense aliphatic C-H stretching bands in the 2900 cm(-1) region relative to the C=C aromatic ring stretching band at 1600 cm(-1). This FTIR spectrum is consistent with the FTIR spectra obtained from algaenans isolated from extant chlorophyte and eustigmatophyte microalgae. FTIR spectra of Leiosphaeridia sp. from the Tanana Formation contain a less intense aliphatic C-H stretching band relative to the C=C aromatic ring stretching band. By comparison, the spectra acquired from the Mesoproterozoic acritarchs were dominated by C=C aromatic ring stretching bands at 1600 cm(-1) relative to moderate-weak CH3 terminal groups (1345 cm(-1)), C-H aliphatic stretching (3000-2700 cm(-1)), and C=O (1710 cm-1), although some differences in biopolymer composition occurred between species. Curve-fitting of the aliphatic C-H, stretching region provides greater insight into the aliphatic structures of the acritarchs. The CH2/CH3 intensity ratio can be used to assess the relative chain length and degree of branching. Organic material in the Tanarium conoideum consists of straight long chain hydrocarbons, while the other acritarchs contain hydrocarbons consisting of short chains that are highly branched. In this study it was found that Raman spectroscopy does not provide additional information about biopolymer composition of Proterozoic acritarchs, but rather offers complementary data regarding the aromaticity and degree of saturation of the macromolecular structure of acritarch cysts. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 25 (0 ULg)
Full Text
Peer Reviewed
See detailCombined Mitochondrial and Nuclear Markers Revealed a Deep Vicariant History for Leopoldamys neilli, a Cave-Dwelling Rodent of Thailand
Latinne, Alice ULg; Waengsothorn, Surachit; Rojanadilok, Prateep et al

in PLoS ONE (2012), 7(10), 47670

Background: Historical biogeography and evolutionary processes of cave taxa have been widely studied in temperate regions. However, Southeast Asian cave ecosystems remain largely unexplored despite their ... [more ▼]

Background: Historical biogeography and evolutionary processes of cave taxa have been widely studied in temperate regions. However, Southeast Asian cave ecosystems remain largely unexplored despite their high scientific interest. Here we studied the phylogeography of Leopoldamys neilli, a cave-dwelling murine rodent living in limestone karsts of Thailand, and compared the molecular signature of mitochondrial and nuclear markers. Methodology/Principal Findings: We used a large sampling (n = 225) from 28 localities in Thailand and a combination of mitochondrial and nuclear markers with various evolutionary rates (two intronic regions and 12 microsatellites). The evolutionary history of L. neilli and the relative role of vicariance and dispersal were investigated using ancestral range reconstruction analysis and Approximate Bayesian computation (ABC). Both mitochondrial and nuclear markers support a large-scale population structure of four main groups (west, centre, north and northeast) and a strong finer structure within each of these groups. A deep genealogical divergence among geographically close lineages is observed and denotes a high population fragmentation. Our findings suggest that the current phylogeographic pattern of this species results from the fragmentation of a widespread ancestral population and that vicariance has played a significant role in the evolutionary history of L. neilli. These deep vicariant events that occurred during Plio-Pleistocene are related to the formation of the Central Plain of Thailand. Consequently, the western, central, northern and northeastern groups of populations were historically isolated and should be considered as four distinct Evolutionarily Significant Units (ESUs). Conclusions/Significance: Our study confirms the benefit of using several independent genetic markers to obtain a comprehensive and reliable picture of L. neilli evolutionary history at different levels of resolution. The complex genetic structure of Leopoldamys neilli is supported by congruent mitochondrial and nuclear markers and has been influenced by the geological history of Thailand during Plio-Pleistocene. [less ▲]

Detailed reference viewed: 41 (5 ULg)
Full Text
Peer Reviewed
See detailCombined Mossbauer Spectral and Density Functional Theory Determination of the Magnetic Easy-Axis in Two High-Spin Iron(II) 2-Pyrazinecarboxylate Complexes
Long, G. J.; Tanase, S.; Remacle, Françoise ULg et al

in Inorganic Chemistry (2009), 48(17), 8173-8179

A combination of density functional theory (DFT) calculations and Mossbauer spectroscopy has been used to determine that the magnetic easy-axis is coincident with its crystallographic c-axis in [Fe(pca)(2 ... [more ▼]

A combination of density functional theory (DFT) calculations and Mossbauer spectroscopy has been used to determine that the magnetic easy-axis is coincident with its crystallographic c-axis in [Fe(pca)(2)(py)(2)]center dot py, where pac is the 2-pyrazinecarboxylate ligand. This easy-axis bisects the approximately axial O-Fe-O coordination axes of molecules adjacent to each other along the b-axis. In {[Fe(pca)(2)(H2O)]center dot H2O}(n) the easy magnetic axis is not coincident with any of its crystallographic axes nor with the Fe-O(water) coordination axis, but is coincident with one of the Fe center dot center dot center dot Fe axes in the crystal structure. The DFT calculations, which use the B3LYP functional and the 6-311 + +G(d,p) basis set, yield s-electron probability densities and electric field gradient tensors for the iron(II) ion that are in excellent agreement with the observed iron-57 Mossbauer spectral isomer shifts and quadrupole interactions. The gas phase results are very similar for calculations based either on the X-ray structures of the two complexes or on their optimized structures; the optimized structures indicate that the iron to ligand bond distances increase in the absence of any solid-state lattice interactions. The results of a normal coordinate vibrational mode analysis of the two optimized structures are compared with the observed infrared spectra. [less ▲]

Detailed reference viewed: 22 (1 ULg)
Peer Reviewed
See detailCombined One Stage Cardiac and Pulmonary Surgery by Median Sternotomy
Adant, J. P.; Defraigne, Jean-Olivier ULg; Limet, Raymond ULg

in Acta Chirurgica Belgica (1990), 90(4), 197-202

From 1985 to 1989, 6 patients underwent a pulmonary surgical procedure simultaneously with a cardiac operation. All patients were male with a mean age of 60 +/- 8 years. The cardiac procedures included: 1 ... [more ▼]

From 1985 to 1989, 6 patients underwent a pulmonary surgical procedure simultaneously with a cardiac operation. All patients were male with a mean age of 60 +/- 8 years. The cardiac procedures included: 1 aortic and 1 mitral valve replacement, 3 coronary artery bypass grafts and 1 closure of an atrial septal defect. Four patients had primary pulmonary nodules: 2 bronchogenic carcinomas and 2 benign hamartomas. They presented with cardiac symptoms, and lung nodules were incidentally found on preoperative Chest X-Rays. The 2 last patients had pulmonary metastases of colonic neoplasms previously resected, respectively 3 and 6 years before. After completion of the cardiac procedures, during the rewarming of the patient, the pulmonary resection was performed on a deflated lung, via the median sternotomy. Pulmonary procedures included: right upper segmentectomy (n = 1), left pneumonectomy (n = 1), left interior lobectomy (n = 1), right middle lobectomy (n = 1), left upper wedge resection (n = 1), and right upper lobe wedge resection (n = 1). All patients were extubated on day one. One patient died from rythm disturbances on day 13. All other patients are alive with a mean survival of 30 months. The authors conclude that combined surgery is feasible in selected cases. Sternal approach is not a limitation to pulmonary resection. [less ▲]

Detailed reference viewed: 9 (0 ULg)
Peer Reviewed
See detailA Combined Optical/Digital SAR Processor for Quicklook Applications
Litovchenko, Konstantin Ts.; Lemaire, Philippe; Barbier, Christian ULg

in Proc. EUSAR'02 Conference (2002)

Detailed reference viewed: 11 (2 ULg)