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See detailLinear amphiphilic diblock copolymers of lactide and 2-dimethylaminoethyl methacrylate using bifunctional-initiator and one-pot approaches
Kryuchkov, Maksym A.; Detrembleur, Christophe ULg; Bazuin, Géraldine

in Polymer (2014), 55(10), 2316-2324

Linear amphiphilic diblock copolymers of polylactide (PLA) and poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) were synthesized by atom transfer radical polymerization (ATRP) of DMAEMA followed by ring ... [more ▼]

Linear amphiphilic diblock copolymers of polylactide (PLA) and poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) were synthesized by atom transfer radical polymerization (ATRP) of DMAEMA followed by ring-opening polymerization (ROP) of LLA using the bifunctional initiator, 2′-hydroxyethyl 2-bromoisobutyrate. NMR showed that the resulting PLA block was racemic and a quaternization/precipitation technique showed that there were significant amounts of racemic PLA homopolymer. In addition, simultaneous ATRP of DMAEMA and ROP of l-lactide by tin octoate were conducted at varied temperatures, indicating 90 °C as a suitable compromise temperature; this one-pot process also led to racemization and P(L)LA homopolymer. The racemization was attributed to reversible deprotonation of LLA by the N(CH3)2 moiety of (P)DMAEMA and the PLA homopolymer impurity was related to in situ formation of lactoyl lactate (LA–LA) due to nucleophilic ring opening of lactide by the amino moieties of (P)DMAEMA. The methods presented can be useful for the preparation of PDMAEMA–b–PLA/PLA composites in a two-step process or in a single step, one-pot process. [less ▲]

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See detailLinear and curvilinear effects of inbreeding on production traits for walloon Holstein cows
Croquet, Coraline; Mayeres, Patrick; Gillon, Alain ULg et al

in Journal of Dairy Science (2007), 90(1), 465-471

The nonlinear effects of inbreeding were studied by comparing linear and curvilinear regression models of phenotypic performances on inbreeding coefficients for production traits (milk, fat, and protein ... [more ▼]

The nonlinear effects of inbreeding were studied by comparing linear and curvilinear regression models of phenotypic performances on inbreeding coefficients for production traits (milk, fat, and protein yields) of Holstein cows in their first lactation. Three different regression models (linear, quadratic, and cubic) were introduced separately into a single-trait, single-lactation, random regression test-day model. The significance of the different regression coefficients was studied based on a t-test after estimation of error variances and covariances associated with the different regression coefficients. All of the tested regression coefficients were significantly different from 0. The traditional regression coefficients of milk, fat, and protein yields on inbreeding were, respectively, -22.10, -1.10, and -0.72 kg for Holstein cows in their first lactation. However, the estimates of 305-d production losses for various classes of animals based on inbreeding coefficients showed that the effect of inbreeding was not a linear function of the percentage of inbreeding. The 305-d milk yield loss profiles attributable to inbreeding, obtained by the various regression models, were different. However, for inbreeding coefficients between 0 and 10%, these differences were small. [less ▲]

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See detailLinear and loglinear structural mean models to evaluate the benefits of an on-demand dosing regimens
Comté, Laetitia ULg; Vansteelandt, Stijn; Tousset, Eric et al

in Clinical Trials : Journal of the Society for Clinical Trials (2009), 6(5), 403-415

Background Structural mean models (SMM) can be used to estimate treatment efficacy when drug exposure varies. We applied SMM to evaluate the clinical benefits of a proton pump inhibitor prescribed to be ... [more ▼]

Background Structural mean models (SMM) can be used to estimate treatment efficacy when drug exposure varies. We applied SMM to evaluate the clinical benefits of a proton pump inhibitor prescribed to be taken as needed to alleviate epigastric pain. We also investigated a new diagnostic approach to evaluate model assumptions. Methods All patients were suffering from non-erosive reflux disease or functional ulcer-like dyspepsia and were prescribed a proton pump inhibitor to be taken as needed for relief of epigastric pain. The primary endpoint was a score variable that expresses the magnitude of gastro-intestinal symptoms at 8 weeks after randomization. We developed linear and loglinear versions of the SMM to derive an unbiased estimator of the reduction in symptom score as a function of exposure to the test drug. Semi-parametric models based on splines and corresponding simultaneous confidence bands identified the presence of potential interactions between drug exposure and baseline covariates. Results The on-demand dosing regimen generated a wide range of drug exposure. Application of SMM showed that the potential treatment induced reduction in symptom score was much greater than the average treatment reduction observed in this population of patients. Our diagnostic tool was useful for detecting the interaction between drug exposure and baseline covariates. Limitations Analysis could only be performed over the two first months after randomization because, afterwards, many patients dropped out from the placebo group. Conclusions The structural mean model approach allows one to estimate treatment efficacy in the presence of variable drug exposure. Similar results were obtained using linear and loglinear SMM. [less ▲]

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See detailLinear and Non-Linear Transonic Flow Behaviour of the Goland+ wing
Vio, Gareth Arthur; Dimitriadis, Grigorios ULg; Cooper, Jonathan Edward et al

in Proceedings of the 2007 International Forum on Aeroelasticity and Structural Dynamics (2007, June)

This paper is part of a study investigating the prediction of the aeroelastic behavior of aircraft subjected to transonic aerodynamic forces. The main objective of the work is the creation of Reduced ... [more ▼]

This paper is part of a study investigating the prediction of the aeroelastic behavior of aircraft subjected to transonic aerodynamic forces. The main objective of the work is the creation of Reduced Order Models from coupled Computational Fluid Dynamic and Finite Element calculations. The novelty of the approach lies in the identification of different types of Reduced Order Model in different flight regimes. Linear modal models are used in the Mach range range where the full CFD/CSD system is linear and nonlinear modal models in the transonic flight regime where the CFD/CSD system undergoes Limit Cycle Oscillations. Static solutions of the CFD/CSD system are used in order to determine the extent of the nonlinear Mach number range. The model treated in this work is a three-dimensional wing in a transonic flowfield. [less ▲]

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See detailLinear and nonlinear analyses of convective instabilities in evaporating liquid layers
Dondlinger, M.; Margerit, J.; Dauby, Pierre ULg

in On Interfacial Fluid Dynamics And Processes in phyisico-chemical systems (2004)

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See detailLinear and nonlinear analyses of convective instabilities in evaporating liquid layers
Dauby, Pierre ULg; Dondlinger, Mireille; Marjerit, Jonathan et al

in Bulletin of the American Physical Society, Vol. 45, n°9 (2005, November)

The present work consists in a theoretical study of Rayleigh- B'enard-Marangoni instabilities in an evaporating horizontal liquid layer which is surmounted by a mixture of its vapour and an inert gas. The ... [more ▼]

The present work consists in a theoretical study of Rayleigh- B'enard-Marangoni instabilities in an evaporating horizontal liquid layer which is surmounted by a mixture of its vapour and an inert gas. The fluid and the gas mixture form a 2-layer system but simplified models can be built to analyse the behaviour of the system. In particular, a 1-layer model can be deduced by introducing a generalized Biot number. In the so- called 1.5-layer approximation, the behaviour of the gas is simplified by only keeping the linear equation of vapour diffusion. In the linear study of thermoconvective instabilities, both simplified models are shown to be in good agreement with the complete 2-layer system. For the non linear approach, only the simplified models are considered. A Galerkin-Eckhaus method is used to deduce amplitude equations for the weakly nonlinear analysis of the problem. The stability domains for the rolls, squares and hexagonal patterns emerging above threshold are determined. Both water and ethanol are used as fluids, while the inert gas is assumed to be air. [less ▲]

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See detailLinear and nonlinear optical properties of functionalized CdSe quantum dots prepared by plasma sputtering and wet chemistry
Humbert, Christophe; Dahi, Abdellatif; Dalstein, Laetitia et al

in Journal of Colloid & Interface Science (2015), 445

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See detailLinear and nonlinear piezoelectric shunting strategies for vibration mitigation
Soltani, Payam ULg; Tondreau, Gilles; Deraemaeker, Arnaud et al

Scientific conference (2014, September 01)

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See detailLinear and nonlinear Rayleigh-Bénard-Marangoni instability with surface deformations
Regnier, Vincent; Dauby, Pierre ULg; Lebon, Georgy ULg

in Physics of Fluids (2000), 12

Thermoconvective instabilities in a bilayer liquid-gas system with a deformed interface are investigated. In the first part of the work which is devoted to a linear approach, emphasis is put on the role ... [more ▼]

Thermoconvective instabilities in a bilayer liquid-gas system with a deformed interface are investigated. In the first part of the work which is devoted to a linear approach, emphasis is put on the role of the upper gas layer on the instability phenomenon. The condition to be satisfied by the gas to remain purely conductive is established. The so-called Oberbeck-Boussinesq approximation is discussed and its range of validity is carefully defined. Instead of the classical Rayleigh, Marangoni, crispation, and Galileo numbers, new dimensionless groups are introduced. A critical comparison with several previous works is made. The nonlinear analysis consists in studying the different convective patterns which can appear above the threshold. Particular attention is devoted to the shape of the interface and the so-called ``hybrid'' relief. The amplitude of the deformation is also determined and comparison with experimental data is discussed. [less ▲]

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See detailLinear and nonlinear thermal instability of a rotating saturated porous medium heated from below
Desaive, Thomas ULg; Hennenberg, M.; Lebon, Georgy ULg

in 1st international conference on applications of porous media (2002)

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See detailLinear and propeller-like fluoro-isoindigo based donor–acceptor small molecules for organic solar cells
Ouhib, Farid ULg; Tomassetti, Mirco ULg; Dierckx, Wauter et al

in Organic Electronics (2015), 20

Two donor–acceptor type fluoro-isoindigo based small molecule semiconductors are syn- thesized and their optical, electrochemical, thermal, and charge transport properties are investigated. The two ... [more ▼]

Two donor–acceptor type fluoro-isoindigo based small molecule semiconductors are syn- thesized and their optical, electrochemical, thermal, and charge transport properties are investigated. The two molecular chromophores differ by their architecture, linear (M1) vs propeller-like (M2). Both molecules present a broad absorption in the visible range and a low optical HOMO–LUMO gap (?1.6 eV). AFM images of solution-processed thin films show that the trigonal molecule M2 forms highly oriented fibrils after a few seconds of solvent vapor annealing. The materials are evaluated as electron donor components in bulk heterojunction organic solar cells using PC61BM as the electron acceptor. The devices based on the propeller-like molecule M2 exhibit a high open-circuit voltage (around 1.0 V) and a power conversion efficiency of 2.23%. [less ▲]

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See detailLinear Benard-Marangoni instability in rigid circular containers
Dauby, Pierre ULg; Lebon, Georgy ULg; Bouhy, E.

in Physical Review. E : Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics (1997), 56(1), 520-530

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See detailLinear coupling between the Rayleigh-Bénard instability and rotation for a ferrofluid in a normal magnetic fluid
Hennenberg, M.; Weyssow, B.; Desaive, Thomas ULg et al

in The first international conference on applications of porous media (2002)

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See detailLinear electro-optic effect in multiferroic BiFeO3 thin films
Sando, D.; Hermet, Patrick ULg; Allibe, J. et al

in Physical Review B (2014), 89

Multiferroics are materials with coexisting magnetic and ferroelectric orders, which show potential for electrically controlled spintronic devices. A common application of ferroelectrics is in electro ... [more ▼]

Multiferroics are materials with coexisting magnetic and ferroelectric orders, which show potential for electrically controlled spintronic devices. A common application of ferroelectrics is in electro-optical modulators exploiting their electric-field-dependent optical indices. The coupling of optical and magnetic degrees of freedom is attractive for designing multifunctional devices, but to date the electro-optical response of multiferroics has hardly been explored. Here we report a joint experimental and theoretical study of this effect in multiferroic BiFeO3 thin films. We confirm the large birefringence present in single crystals and determine the electro-optic coefficients r13 and r33. We present approaches to increase the obtained coefficients, for instance, by using tetragonal-like BiFeO3, and expand the potential of multiferroics to optical applications. [less ▲]

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See detailLinear foreign bodies in cats
Hamaide, Annick ULg

in Proceedings du 15th congrès FECAVA (2009, November)

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See detailLinear formulation of identifying cdes in graphs
Vandomme, Elise ULg; Gravier, Sylvain; Parreau, Aline ULg

Poster (2013, September 09)

Identifying codes were introduced by Karpovsky, Chakrabarty and Levitin in 1998 and can be applied to locate fire in a building using sensors. Buildings are modelled by graphs with rooms as vertices. The ... [more ▼]

Identifying codes were introduced by Karpovsky, Chakrabarty and Levitin in 1998 and can be applied to locate fire in a building using sensors. Buildings are modelled by graphs with rooms as vertices. The placement of sensors in the rooms corresponds to choosing a subset of vertices. Finding a sensor-placement such that the location of a fire in one room can be precisely determined is equivalent to constructing an identifying code in the graph. These are dominating sets of vertices for which the closed neighbourhood of each vertex (i.e., the vertex and its neighbours) has a unique intersection with the set. The problem of finding an identifying code has been widely studied. Yet its formulation as an integer linear problem hasn't been much considered. Let G be a graph with vertex set V, to an identifying code $C\subseteq V$ of $G$ correspond weights x_u (x_u is 1 if u belongs to C, otherwise x_u is 0) satisfying the following : for all vertices u,v * the sum of the x_w for w in the closed neighbourhood of u is at least 1 * the sum of the x_w for w in the symmetric difference of the closed neighbourhoods of u and v is at least 1. Of course, it is interesting to find an identifying code with the smallest possible cardinality. But in general this is a NP-hard problem. A way to obtain bounds on the minimal cardinality is to consider the associated linear problem where the weights x_u are fractional. In the case of vertex-transitive graphs, the minimal cardinality for the fractional case can only take two values which depend on the number of vertices, the degree of the graph and the smallest symmetric difference between any two closed neighbourhoods. We show that for an infinite family of graphs the bound is tight and for another another the bound is far too be reached. [less ▲]

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See detailLinear growth and final height after treatment for Cushing's disease in childhood.
LEBRETHON, Marie-Christine ULg; Grossman, A. B.; Afshar, F. et al

in The Journal of clinical endocrinology and metabolism (2000), 85(9), 3262-5

Cushing's disease is associated with growth failure in childhood and adolescence. Growth and final height were analyzed in 10 patients who were cured or in remission after treatment of Cushing's disease ... [more ▼]

Cushing's disease is associated with growth failure in childhood and adolescence. Growth and final height were analyzed in 10 patients who were cured or in remission after treatment of Cushing's disease. Seven males and 3 females, aged 6.8-17.6 yr (bone age, 3.3-15.4 yr), had transsphenoidal surgery, which was combined with pituitary irradiation (4,500 cGy in 25 fractions) in 5 patients. At presentation, 5 patients were prepubertal (males), and 5 were pubertal (2 males and 3 females). The mean height SD score was -2.15 +/-1.26 (range, -0.21 to -4.32) compared with mean target height SD score of -0.43 +/- 0.58. Height velocity in 6 patients was subnormal (0.9-3.8 cm/yr). After treatment, short-term height velocity, over a mean interval of 0.57 yr, in 8 patients not receiving human GH (hGH) therapy, was variable (range, 0.8-7.6 cm/yr). GH stimulation tests (insulin tolerance test/glucagon) in 9 subjects showed peak GH levels of 0.5-20.9 mU/L. Eight were treated with hGH (14 IU/m2 wk), combined in 2 girls and 1 boy with a GnRH analog. After 1 yr of hGH, the mean height SD score had increased from -2.45 +/- 1.0 at initiation of hGH to -2.07 +/- 1.2 (P = 0.01). GH therapy was continued until final height or latest assessment. The mean final height SD score (n = 6) was - 1.24 +/- 1.38, and at the latest assessment the mean height SD score (n = 4) was - 1.52 +/- 1.33. Combining these 2 groups, the mean height so score was -1.36 +/- 1.29. The difference between final or latest height SD score and target height SD score was 0.93 +/- 1.13, i.e. less (P = 0.005) than the difference between height and target height SD score of 1.72 +/- 1.26 at presentation. In conclusion, catch-up and favorable long-term growth was seen after treatment for Cushing's disease. Posttreatment GH deficiency was frequent, and early hGH replacement may have contributed to the encouraging outcome. [less ▲]

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See detailLinear magnetoelectric effect by orbital magnetism
Scaramucci, A.; Bousquet, Eric ULg; Fechner, M. et al

in Physical Review Letters (2012), 109(19),

We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an ... [more ▼]

We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an applied electric field. Using LiFePO 4 as a model compound we show that spin-orbit coupling partially lifts the quenching of the 3d orbitals and causes small orbital magnetic moments (μ (L)≈0.3μ B) parallel to the spins of the Fe2 + ions. An applied electric field E modifies the size of these orbital magnetic moments inducing a net magnetization linear in E. © 2012 American Physical Society. [less ▲]

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See detailLinear regression under fixed-rank constraints: a Riemannian approach
Meyer, Gilles ULg; Bonnabel, Silvère; Sepulchre, Rodolphe ULg

in Proceedings of the 28th International Conference on Machine Learning (2011)

In this paper, we tackle the problem of learning a linear regression model whose parameter is a fixed-rank matrix. We study the Riemannian manifold geometry of the set of fixed-rank matrices and develop ... [more ▼]

In this paper, we tackle the problem of learning a linear regression model whose parameter is a fixed-rank matrix. We study the Riemannian manifold geometry of the set of fixed-rank matrices and develop efficient line-search algorithms. The proposed algorithms have many applications, scale to high-dimensional problems, enjoy local convergence properties and confer a geometric basis to recent contributions on learning fixed-rank matrices. Numerical experiments on benchmarks suggest that the proposed algorithms compete with the state-of-the-art, and that manifold optimization offers a versatile framework for the design of rank-constrained machine learning algorithms. [less ▲]

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See detailLinear Repeating Points [chap. 13]
Wolper, Pierre ULg

in Kuper, Gabi; Libkin, Leonid; Paredaens, Jan (Eds.) Constraint Databases (2000)

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