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See detailIntratumoral heterogeneity and consequences for targeted therapies
Turtoi, Andrei ULg; Blomme, Arnaud ULg; Castronovo, Vincenzo ULg

in Bulletin du Cancer (2015), 102(1), 17-23

According to the clonal model and Darwinian evolution, cancer cell evolves through new mutations helping it to proliferate, migrate, invade and metastasize. Recent genetic studies have clearly shown that ... [more ▼]

According to the clonal model and Darwinian evolution, cancer cell evolves through new mutations helping it to proliferate, migrate, invade and metastasize. Recent genetic studies have clearly shown that tumors, when diagnosed, consist of a large number of mutations distributed in different cells. This heterogeneity translates in substantial genetic plasticity enabling cancer cells to adapt to any hostile environment. As targeted therapy focuses only on one pathway or protein, there will always be a cell with the "right" genetic background to survive the treatment and cause tumor relapse. Because today's targeted therapies never took tumor heterogeneity into account, nearly all novel drugs fail to provide patients with a considerable improvement of the survival. However, emerging proteomic studies guided by the idea that Darwinian selection is governed by the phenotype and not genotype, show that heterogeneity at the protein level is much less complex, then it could be expected from genetic studies. This information together with the recent trend to switch from functional to cytotoxic targeting may offer an entirely new strategy to efficiently combat cancer. [less ▲]

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See detailDes bandes urbaines en Belgiques?
Collin, Jonathan ULg

Conference given outside the academic context (2015)

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See detailNederlands-Frans in contrast. 2000 lexicologische valstrikken in het Frans voor Nederlandstaligen
Theissen, Siegfried ULg; Hiligsmann, Philippe; Rasier, Laurent ULg et al

Book published by Acco (2015)

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See detailDetermination of arsenic (III) at a nano gold modified solid carbon paste electrode
Sakira, Abdoul Karim; Somé, Issa Touridomon; Ziemons, Eric ULg et al

in Electroanalysis (2015), 27

A selective and sensitive electroanalytical method was developed for arsenic determination based on a nanogold (AuNP) modified solid carbon paste work- ing electrode (SCPE) modified in two steps (i ... [more ▼]

A selective and sensitive electroanalytical method was developed for arsenic determination based on a nanogold (AuNP) modified solid carbon paste work- ing electrode (SCPE) modified in two steps (i) physisorp- tion and (ii) additional electrodeposition of nanogold par- ticles in the presence of iodide. Copper(II) interference was solved by covering the gold layer by a self assembled mono layer (SAM) of glutathione. Using DPASV a linear response of the signal was obtained as a function of As(III) in the concentration range 0.05–20mM (4– 1498 ppb) with a limit of detection of 0.01 mM (0.9 ppb). Sample stirring and degassing were not needed. Applica- tion to the determination of arsenic(III) and (V) in un- derground water samples from Burkina Faso was success- fully achieved. [less ▲]

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See detailAdventitious organogenesis induced in sweet orange (Citrus sinensis L.) var. "half-blood" maltese: morphogenetic and histological study
Benmahmoud, Kaouther; Jedidi, Zmna; Najar, Asma et al

in International Journal of Agronomy and Agricultural Research (2015), 6(2), 1-7

Tunisian citrus crops are faced to several abiotic and biotic constraints among which virus and virus-like diseases are incurable. The production of virus-free plants systematically needs the use of in ... [more ▼]

Tunisian citrus crops are faced to several abiotic and biotic constraints among which virus and virus-like diseases are incurable. The production of virus-free plants systematically needs the use of in vitro techniques. In this context, somatic embryogenesis and further plantlet regeneration of the Tunisian “half-blood” Maltese orange were obtained using explants consisting in style/stigma collected from unopened flowers. Somatic embryos were induced on Murashige and Skoog medium containing 13.3 µM 6-benzylaminopurine and 500 mg.l-1 malt extract, but their germination was obtained on hormone free-medium. Somatic embryogenesis was induced indirectly from intermediate friable callus initiated at the basal part of the style. Somatic embryos exhibited central procambial cells and were surrounded by a protoderm isolating them from the callus. These embryos had bipolar structure confirmed by the presence of shoot and root apices at cotyledonary stage. The use of cotyledon excised from those embryos failed to regenerate somatic embryos, but gave rise to direct organogenesis in two forms, true buds and protuberances both evolved in shoots after transfer in hormone-free medium. According to histological observations, protuberances are induced from epidermal and subepidermal cells of the cotyledon explant and remain closely attached to their mother tissue even at the shoot stage. [less ▲]

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See detailSolar Energy Prediction: An International Contest to Initiate Interdisciplinary Research on Compelling Meteorological Problems
McGovern, Amy; Gagne II, David John; Eustaquio, Lucas et al

in Bulletin of the American Meteorological Society [= BAMS] (2015)

As meteorological observing systems and models grow in complexity and number, the size of the data becomes overwhelming for humans to analyze using traditional techniques. Computer scientists, and ... [more ▼]

As meteorological observing systems and models grow in complexity and number, the size of the data becomes overwhelming for humans to analyze using traditional techniques. Computer scientists, and specifically machine learning and data mining researchers, are developing frameworks for analyzing big data. The AMS Committee on Artificial Intelligence and its Applications to Environmental Science aims to bring AI researchers and environmental scientists together to increase the synergy between the two. The AI committee has sponsored 4 previous contests on a variety of meteorological problems including wind energy, storm classification, winter hydrometeor classification, and air pollution, with the goal of bringing together the two fields of research. Although these were successful, the audience was limited to existing environmental science researchers (usually 10-20 teams of people primarily within the AMS community). For the 2013/14 contest, we expanded to a global audience by focusing on the compelling problem of solar energy prediction and by having the established forum Kaggle host our contest. Using this forum, we had over 160 teams from all around the world participate. Improved solar energy forecasting is a necessary component of making solar energy a viable alternative power source. This paper summarizes our experiences in the 2013/14 contest, discusses the data in detail, and presents the winning prediction methods. The contest data come from the NOAA/ESRL Global Ensemble Forecasting System Reforecast Version 2 and the Oklahoma Mesonet with sponsorship from EarthRisk Technologies. All winning methods utilized gradient boosted regression trees but differed in parameter choices and interpolation methods. [less ▲]

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See detailSolutrean and Magdalenian ferruginous rocks heat-treatment: accidental and/or deliberate action?
Salomon, Hélène ULg; Vignaud, Colette; Lahlil, Sophia et al

in Journal of Archaeological Science (2015), 55

Heating of prehistoric coloring materials can induce radical changes in color indicative of structural matter transformation. For instance, the structure of the yellow iron oxide-rich mineral, goethite ... [more ▼]

Heating of prehistoric coloring materials can induce radical changes in color indicative of structural matter transformation. For instance, the structure of the yellow iron oxide-rich mineral, goethite, changes into the red iron oxide-rich mineral, hematite, when it is heated to around 250-300°C. For a long time, heating has been thought to be the reason for the high frequencies of red rocks used in camp sites and the red pigments in rock art paintings. However, records of heat-treatment of coloring materials are usually not well documented; the contextual information is not clear enough to confirm intentional heating. Two Solutrean camp sites (the flint workshop Les Maîtreaux and the hunting site Combe Saunière I) and one middle Magdalenian cave with rock art (Grotte Blanchard, La Garenne) allow us to study the heating process of ferruginous rocks. All three sites, which have been excavated relatively recently, have well-defined archaeological records and strong associations between the ferruginous rocks and other artifacts. With the use of X-ray diffraction and electron µ-diffraction for identifying structural modification and SEM-FEG and TEM-FEG for detecting dehydration nano-pores, we have strong evidence for intentional heat-treatment of yellow goethite-rich materials in two archaeological contexts and one site for unintentional heating, where rocks were only partially transformed. Intentional heating to obtain red hematite from primary goethite would have required ingenious methods of temperature control in fireplace settings and purpose-built ground ovens. [less ▲]

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See detailSupervised inference of biological networks with trees : Application to genetic interactions in yeast
Schrynemackers, Marie ULg

Doctoral thesis (2015)

Networks or graphs provide a natural representation of molecular biology knowledge, in particular to model relationships between biological entities such as genes, proteins, drugs, or diseases. Because of ... [more ▼]

Networks or graphs provide a natural representation of molecular biology knowledge, in particular to model relationships between biological entities such as genes, proteins, drugs, or diseases. Because of the effort, the cost, or the lack of the experiments necessary to the elucidation of these networks, computational approaches for network inference have been frequently investigated in the literature. In this thesis, we focus on supervised network inference methods. These methods exploit supervised machine learning algorithms to train a model for identifying new interacting pairs of nodes from a training sample of known interacting and possibly non-interacting pairs and additional measurement data about the network nodes. Our contributions in this area are divided into three parts. First, the thesis examines the problem of the assessment of supervised network inference methods. Indeed, their reliable validation (in silico) poses a number of new challenges with respect to standard classification problems, related to the fact that pairs of objects are to be classified and to the specificities of biological networks. We perform a critical review and assessment of protocols and measures proposed in the literature. Through theoretical considerations and in silico experiments, we analyze in depth how important factors influence the outcome of performance estimation. These factors include the amount of information available for the interacting entities, the sparsity and topology of biological networks, and the lack of experimentally verified non-interacting pairs. From this analysis, we derived specific guidelines so as to how best exploit and evaluate machine learning techniques for network inference. Second, we systematically investigate, theoretically and empirically, the exploitation of tree- based methods for network inference. We consider these methods in the context of the two main generic classification-based approaches for network inference: the local approach, which trains a separate model for each network node, and the global approach, which trains a single model over pairs of nodes. We present and formalize these two approaches, extending the former for the prediction of interactions between two unseen network nodes, and discuss their specializations to tree-based methods, highlighting their interpretability and drawing links with clustering techniques. Extensive experiments are carried out with these methods on various biological networks that clearly highlight that these methods are competitive with existing methods. The interpretability of the resulting method family is illustrated on a drug-protein interaction network. In the last part of the thesis, we built on the experience gained in the two previous parts to try to predict at best the genetic interaction network in yeast S.cerevisiae. For that purpose, we collected a large dataset, assembling 4 millions gene pairs that were experimentally tested in the context of 11 different studies and 23 sets of measurements to use as gene input features for the inference. Through several cross-validation experiments on the resulting dataset, we showed that predicting genetic interactions is indeed possible to some useful extent and that actually in some settings, the accuracy of computational methods is not very far from that of experimental techniques. [less ▲]

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See detailAnalyzing Access, Egress, and Main Transport Mode of Public Transit Journeys: Evidence from the Flemish National Household Travel Survey
Creemers, Lieve; Bellemans, Tom; Janssens, Davy et al

in Proceedings of the 94th Annual Meeting of the Transportation Research Board (2015)

The primary objective of this paper is to explore the influence of socio-demographic and contextual variables on the multimodal character of public transit journeys. Accounting for multimodality in public ... [more ▼]

The primary objective of this paper is to explore the influence of socio-demographic and contextual variables on the multimodal character of public transit journeys. Accounting for multimodality in public transit journeys is important from a demand modeling point of view, especially in the assessment of new projected public transit infrastructure. To meet the objective, data from the national household travel survey of Flanders (Belgium) is analyzed. Based on 2,202 public transit journeys, the main public transit mode choice (bus/tram/metro or train) and access/egress mode choice are simultaneously estimated using a multinomial logit model, and by explicitly making a distinction between unimodal and multimodal transit journeys. The results indicate that various socio-demographical (e.g. age, gender, level of education, household income) and contextual factors (e.g. journey distance, journey motive, urbanization degree, car availability) significantly influence the joint decision process. Total journey distance and car availability are identified as the most important explanatory variables. In terms of model performance, the model appears to yield satisfactory predictions, justifying the integration of the model in more general demand modeling frameworks. [less ▲]

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See detailPredicting biomass and grain protein content using Bayesian methods
Mansouri, Majdi ULg; Destain, Marie-France ULg

in Stochastic Environmental Research & Risk Assessment (2015)

This paper deals with the problem of predicting biomass and grain protein content using improved particle filtering (IPF) based on minimizing the Kullback–Leibler divergence. The performances of IPF are ... [more ▼]

This paper deals with the problem of predicting biomass and grain protein content using improved particle filtering (IPF) based on minimizing the Kullback–Leibler divergence. The performances of IPF are compared with those of the conventional particle filtering (PF) in two comparative studies. In the first one, we apply IPF and PF at a simple dynamic crop model with the aim to predict a single state variable, namely the winter wheat biomass, and to estimate several model parameters. In the second study, the proposed IPF and the PF are applied to a complex crop model (AZODYN) to predict a winter-wheat quality criterion, namely the grain protein content. The results of both comparative studies reveal that the IPF method provides a better estimation accuracy than the PF method. The benefit of the IPF method lies in its ability to provide accuracy related advantages over the PF method since, unlike the PF which depends on the choice of the sampling distribution used to estimate the posterior distribution, the IPF yields an optimum choice of this sampling distribution, which also utilizes the observed data. The performance of the proposed method is evaluated in terms of estimation accuracy, root mean square error, mean absolute error and execution times. [less ▲]

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See detailTiO2 Macroscopic Fibers with Enhanced Photocatalytic Properties Obtained through a Scale-Up Semi-Industrial Process
Kinadjian, Natacha; Le Bechec, Mickael; Henrist, Catherine ULg et al

in Advanced Engineering Materials (2015), 17(1), 36-44

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See detailBayesian inference for transportation origin–destination matrices: the Poisson–inverse Gaussian and other Poisson mixtures
Perrakis, Konstantinos; Karlis, Dimitris; Cools, Mario ULg et al

in Journal of the Royal Statistical Society. Series A Statistics in Society (2015), 178(1), 271-296

Transportation origin–destination analysis is investigated through the use of Poisson mixtures by introducing covariate-based models which incorporate different transport modelling phases and also allow ... [more ▼]

Transportation origin–destination analysis is investigated through the use of Poisson mixtures by introducing covariate-based models which incorporate different transport modelling phases and also allow for direct probabilistic inference on link traffic based on Bayesian predictions. Emphasis is placed on the Poisson–inverse Gaussian model as an alternative to the commonly used Poisson–gamma and Poisson–log-normal models. We present a first full Bayesian formulation and demonstrate that the Poisson–inverse Gaussian model is particularly suited for origin–destination analysis because of its desirable marginal and hierarchical properties. In addition, the integrated nested Laplace approximation is considered as an alternative to Markov chain Monte Carlo sampling and the two methodologies are compared under specific modelling assumptions. The case-study is based on 2001 Belgian census data and focuses on a large, sparsely distributed origin–destination matrix containing trip information for 308 Flemish municipalities. [less ▲]

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See detailMerging multi-camera data to reduce motion analysis instrumental errors using Kalman filters
Schwartz, Cédric ULg; Denoël, Vincent ULg; Forthomme, Bénédicte ULg et al

in Computer Methods in Biomechanics and Biomedical Engineering (2015), 18(9), 952-960

In motion capture systems, markers are often seen by multiple cameras. All cameras do not measure the position of the markers with the same reliability because of environmental factors such as the ... [more ▼]

In motion capture systems, markers are often seen by multiple cameras. All cameras do not measure the position of the markers with the same reliability because of environmental factors such as the position of the marker in the field of view or the light intensity received by the cameras. Kalman filters offer a general framework to take the reliability of the various cameras into account and consequently improve the estimation of the marker position. The proposed process can be applied to both passive and active systems. Several reliability models of the cameras are compared for the Codamotion active system, which is considered as a specific illustration. The proposed method significantly reduces the noise in the signal, especially at long range distances. Therefore, it improves the confidence of the positions at the limits of the field of view. [less ▲]

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See detailPaleomagnetic and geochemical record from cores from the Sea of Marmara, Turkey: Age constraints and implications of sapropelic deposition on early diagenesis
Drab, Laureen; Carlut, Julie; Hubert, Aurelia ULg et al

in Marine Geology (2015), 360

We present results of a multi-proxy analysis of two sediment cores from the Marmara Sea. The cores were ana- lyzed using paleomagnetic and geochemical measurements. Two sapropels are documented in the ... [more ▼]

We present results of a multi-proxy analysis of two sediment cores from the Marmara Sea. The cores were ana- lyzed using paleomagnetic and geochemical measurements. Two sapropels are documented in the last 11 kyr and are recorded in several locations across the Marmara Sea. These two sapropels have contrasting magnetic prop- erties. The magnetic record is affected by intense early diagenesis; the most recent upper sapropelic layer has low remanence and susceptibility values. A record of paleomagnetic inclinations could still be isolated above the dia- genesis front and is compared with secular variation models. The lower sapropel is identified in the deep part of the oldest studied core (Klg07) and has distinct magnetic properties characterized by high remanence and sus- ceptibility values. Using the magnetic properties it is possible to constrain bottom water ventilation and recon- nection episodes between the Marmara Sea and the Black Sea following the sea level rise during the last glacial to inter-glacial transition. [less ▲]

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See detailLearning the Tactile Signatures of Prototypical Object Parts for Robust Part-based Grasping of Novel Objects
Hyttinen, Emil; Kragic, Danica; Detry, Renaud ULg

in IEEE International Conference on Robotics and Automation (2015)

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See detailCost-effectiveness of vitamin D and calcium supplementation in the treatment of elderly women and men with osteoporosis.
Hiligsmann, Mickaël ULg; Ben Sedrine, Wafa; Bruyère, Olivier ULg et al

in European journal of public health (2015), 25(1), 20-25

BACKGROUND: The supplementation with vitamin D and calcium has been recommended for elderly, specifically those with increased risk of fractures older than 65 years. This study aims to assess the cost ... [more ▼]

BACKGROUND: The supplementation with vitamin D and calcium has been recommended for elderly, specifically those with increased risk of fractures older than 65 years. This study aims to assess the cost-effectiveness of vitamin D and calcium supplementation in elderly women and men with osteoporosis and therefore to assess if this recommendation is justified in terms of cost-effectiveness. METHODS: A validated model for economic evaluations in osteoporosis was used to estimate the cost per quality-adjusted life-year (QALY) gained of vitamin D/calcium supplementation compared with no treatment. The model was populated with cost and epidemiological data from a Belgian health-care perspective. Analyses were conducted in women and men with a diagnosis of osteoporosis (i.e. bone mineral density T-score </=-2.5). A literature search was conducted to describe the efficacy of vitamin D and calcium in terms of fracture risk reduction. RESULTS: The cost per QALY gained of vitamin D/calcium supplementation was estimated at euro40 578 and euro23 477 in women and men aged 60 years, respectively. These values decreased to euro7912 and euro10 250 at the age of 70 years and vitamin D and calcium supplementation was cost-saving at the age of 80 years, meaning that treatment cost was less than the costs of treating osteoporotic fractures of the no-treatment group. CONCLUSION: This study suggests that vitamin D and calcium supplementation is cost-effective for women and men with osteoporosis aged over 60 years. From an economic perspective, vitamin D and calcium should therefore be administrated in these populations including those also taking other osteoporotic treatments. [less ▲]

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See detailLes difficultés d'apprentissage procédural chez les enfants dysphasiques
Desmottes, Lise ULg; Meulemans, Thierry ULg; Maillart, Christelle ULg

in ANAE : Approche Neuropsychologique des Apprentissages chez l'Enfant (2015)

Through a review of the literature, this paper shows that linguistic and non-linguistic disorders in children with specific language impairment might be linked to difficulties in procedural learning ... [more ▼]

Through a review of the literature, this paper shows that linguistic and non-linguistic disorders in children with specific language impairment might be linked to difficulties in procedural learning, especially regarding sequential abilities. Indeed, children with specific language impairment encounter difficulties to learn visuo-motor and linguistic sequences. These difficulties are not limited to initial learning but extend to the consolidation stage in long-term memory. Finally, recent studies show that it is possible to improve procedural learning abilities, suggesting new avenues for rehabilitation. [less ▲]

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See detailRestoring testosterone levels by adding dehydroepiandrosterone to a drospirenone containing combined oral contraceptive: II. Clinical effects.
Zimmerman, Y.; Foidart, Jean-Michel ULg; Pintiaux, Axelle ULg et al

in Contraception (2015), 91(2), 134-42

OBJECTIVES: Combined oral contraceptives (COCs) decrease androgen levels, including testosterone (T), which may be associated with sexual dysfunction and mood complaints in some women. We have shown that ... [more ▼]

OBJECTIVES: Combined oral contraceptives (COCs) decrease androgen levels, including testosterone (T), which may be associated with sexual dysfunction and mood complaints in some women. We have shown that 'co-administration' of dehydroepiandrosterone (DHEA) to a drospirenone (DRSP)-containing COC restored total T levels to baseline and free T levels by 47%. Here we describe the effects on sexual function, mood and quality of life of such an intervention. STUDY DESIGN: This was a randomized, double-blind, placebo-controlled study in 99 healthy COC starters. A COC containing 30mcg ethinylestradiol (EE) and 3mg DRSP was used for three cycles, followed by six cycles of the same COC combined with 50mg/day DHEA or placebo. Subjects completed the Moos Menstrual Distress Questionnaire (MDQ), the McCoy Female Sexuality Questionnaire and the short form of the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q). Safety and tolerability, including effects on skin, were evaluated. RESULTS: The addition of DHEA induced small but significant improvements compared to placebo in the MDQ score for autonomic reactions during the menstrual (-2.0 vs. 0.71; p=0.05) and the premenstrual phase (-3.1 vs. 2.9; p=0.01) and for behavior during the intermenstrual phase (-1.4 vs. 3.6; p=0.02). A significant difference was found in the MDQ score for arousal during the premenstrual phase in favor of placebo (-5.0 vs. 1.0; p=0.01). There were no statistically significant differences between groups for the MSFQ and Q-LES-Q scores. DHEA 'co-administration' resulted in an acceptable safety profile. DHEA negated the beneficial effect of the COC on acne according to the subjects' self-assessment. CONCLUSIONS: 'Co-administration' with DHEA did not result in consistent improvements in sexual function, mood and quality of life indicators in women taking EE/DRSP. Retrospectively, the 50 mg dose of DHEA may be too low for this COC. IMPLICATIONS: A well-balanced judgment of the clinical consequences of normalizing androgens during COC use may require complete normalization of free T. [less ▲]

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