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See detailModifying eigenvalue interactions near weak resonance
Auvray, Vincent; Dobson, Ian; Wehenkel, Louis ULg

in Proc. of International Symposium on Circuits and Systems (2004)

In electric power system instabilities such as subsynchronous resonance or interarea oscillations, two complex modes can approach each other in frequency and then interact by changing damping so that one ... [more ▼]

In electric power system instabilities such as subsynchronous resonance or interarea oscillations, two complex modes can approach each other in frequency and then interact by changing damping so that one of the modes becomes unstable. Selecting changes in parameters to minimize this interaction is difficult by trial and error. By analyzing the interaction as a perturbation of a weak resonance, we calculate sensitivities that indicate the parameters to be changed to minimize the interaction and stabilize the system. The method is illustrated with a simple example of two coupled linear oscillators. The use of sensitivity methods to change the type of the interaction is also demonstrated. [less ▲]

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See detailUn modo attutito d’esistere: Note su Sbarbaro traduttore dal francese
Benzoni, Pietro ULg

in Ferreri, Davide (Ed.) Camillo Sbarbaro in versi e in prosa (2009)

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See detailA modular approach to quality of life assessment in paediatric oncology
Fonseca, Marta; Missotten, Pierre ULg; Etienne, Anne-Marie ULg et al

in Psychology & Health (2009), 24(Supp 1), 175

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See detailModular changes of cis-regulatory elements from two functional Pit1 genes in the duplicated genome of Cyprinus carpio.
Kausel, G.; Salazar, M.; Castro, L. et al

in Journal of Cellular Biochemistry (2006), 99(3), 905-21

The pituitary-specific transcription factor Pit1 is involved in its own regulation and in a network of transcriptional regulation of hypothalamo-hypophyseal factors including prolactin (PRL) and growth ... [more ▼]

The pituitary-specific transcription factor Pit1 is involved in its own regulation and in a network of transcriptional regulation of hypothalamo-hypophyseal factors including prolactin (PRL) and growth hormone (GH). In the ectotherm teleost Cyprinus carpio, Pit1 plays an important role in regulation of the adaptive response to seasonal environmental changes. Two Pit1 genes exist in carp, a tetraploid vertebrate and transcripts of both genes were detected by RT-PCR analysis. Powerful comparative analyses of the 5'-flanking regions revealed copy specific changes comprising modular functional units in the naturally evolved promoters. These include the precise replacement of four nucleotides around the transcription start site embedded in completely conserved regions extending upstream of the TATA-box, an additional transcription factor binding site in the 5'-UTR of gene-I and, instead, duplication of a 9 bp element in gene-II. Binding of nuclear factors was assessed by electro mobility shift assays using extracts from rat pituitary cells and carp pituitary. Binding was confirmed at one conserved Pit1, one conserved CREB and one consensus MTF1. Interestingly, two functional Pit1 sites and one putative MTF1 binding site are unique to the Pit1 gene-I. In situ hybridization experiments revealed that the expression of gene-I in winter carp was significantly stronger than that of gene-II. Our data suggest that the specific control elements identified in the proximal regulatory region are physiologically relevant for the function of the duplicated Pit1 genes in carp and highlight modular changes in the architecture of two Pit1 genes that evolved for at least 12 MYA in the same organism. [less ▲]

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See detailModular Design of the Bi(multi?) functional penicillin-binding proteins
Englebert, Serge; El Kharroubi, Aboubaker; Piras, Graziella et al

in De pedro; Höltje, J. V.; Loffelhardt, W. (Eds.) Bacterial Growth & Lysis Metabolism and Structure of the Bacterial Sacculus (1993)

Proceedings of a symposium held in Mallorca, Spain in April 1992. The goal of the meeting was to assess the present state of knowledge on the structure and physiology of the bacterium murien sacculus, and ... [more ▼]

Proceedings of a symposium held in Mallorca, Spain in April 1992. The goal of the meeting was to assess the present state of knowledge on the structure and physiology of the bacterium murien sacculus, and develop new hypotheses and strategies to promote further development of the field. The contributions reflect broadly different approaches. Papers discuss structure and chemistry, biosynthesis and maturation, regulation and control of cell wall hydrolases, penicillin interactive proteins, morphogenesis and septum formation, and cell growth. Annotation c. Book News, Inc., Portland, OR (booknews.com) [less ▲]

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See detailModular Design of the Enterococcus Hirae Muramidase-2 and Streptococcus Faecalis Autolysin
Joris, Bernard ULg; Englebert, Serge; Chu, Chien-Peng et al

in FEMS Microbiology Letters (1992), 91(3), 257-264

The mature forms of the extracellular muramidase-2 of Enterococcus hirae and Streptococcus faecalis autolysin have very similar primary structures. Each consists of an active-site-containing N-terminal ... [more ▼]

The mature forms of the extracellular muramidase-2 of Enterococcus hirae and Streptococcus faecalis autolysin have very similar primary structures. Each consists of an active-site-containing N-terminal domain fused to a multiple-repeat C-terminal domain. Polypeptide segments occurring at equivalent places in these two bacterial wall lytic enzymes have homologues in two phage lysozymes and in three functionally unrelated proteins, illustrating the principle that protein molecules frequently are constructed from modules that are linked in a single polypeptide chain. [less ▲]

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See detailModular mechatronic modelling for wind turbine generating systems based on an integrated finite element approach
Chen, Qiongzhong ULg; Jetteur, Philippe; Bruls, Olivier ULg

in Proceedings of the First Joint International Conference on Multibody System Dynamics (2010, May)

Wind energy is nowadays the fastest-growing energy source in the world, which has been attracting a lot of research interest in wind turbine generator systems. This paper concerns the modelling and ... [more ▼]

Wind energy is nowadays the fastest-growing energy source in the world, which has been attracting a lot of research interest in wind turbine generator systems. This paper concerns the modelling and simulation of wind turbine generating systems using the flexible multibody simulation software SAMCEF/MECANO. Firstly, it introduces the formulation of an extension of the generalized-alpha method, which is integrated into the flexible multibody dynamics solver for strongly-coupled simulation of mechatronic systems, and then emphasizes on the doubly-fed induction generator (DFIG) and the controller models, which are developed as modular components of the wind turbine package. The mechatronic systems are simulated upon this strongly-coupled approach and simulation results show the validity of the newly-developed solver and the models. The interest of this work is to analyze the control-generator-structure interactions in a wind turbine. The general aim is to develop a computer-aided tool for customization, fast-prototyping and optimal design of wind turbine systems based on the dynamic simulation of the overall system. [less ▲]

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See detailA Modular Multi-camera Framework for Team Sport Tracking
Hayet, Jean-Bernard; Mathes, Thomas; Czyz, Jacek et al

Conference (2005)

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See detailModular mutagenesis of a TIM-barrel enzyme: the crystal structure of a chimeric E. coli TIM having the eighth beta alpha-unit replaced by the equivalent unit of chicken TIM
Kishan, Radha; Zeelen, Ph. Johan; Noble, Martin E.M. et al

in Protein Engineering (1994), 7(8), 945-51

The crystal structure of a hybrid Escherichia coli triosephosphate isomerase (TIM) has been determined at 2.8 A resolution. The hybrid TIM (ETIM8CHI) was constructed by replacing the eighth beta alpha ... [more ▼]

The crystal structure of a hybrid Escherichia coli triosephosphate isomerase (TIM) has been determined at 2.8 A resolution. The hybrid TIM (ETIM8CHI) was constructed by replacing the eighth beta alpha-unit of E. coli TIM with the equivalent unit of chicken TIM. This replacement involves 10 sequence changes. One of the changes concerns the mutation of a buried alanine (Ala232 in strand 8) into a phenylalanine. The ETIM8CHI structure shows that the A232F sequence change can be incorporated by a side-chain rotation of Phe224 (in helix 7). No cavities or strained dihedrals are observed in ETIM8CHI in the region near position 232, which is in agreement with the observation that ETIM8CHI and E.coli TIM have similar stabilities. The largest CA (C-alpha atom) movements, approximately 3 A, are seen for the C-terminal end of helix 8 (associated with the outward rotation of Phe224) and for the residues in the loop after helix 1 (associated with sequence changes in helix 8). From the structure it is not clear why the kcat of ETIM8CHI is 10 times lower than in wild type E.coli TIM. [less ▲]

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See detailModular Structure, Local Flexibility and Cold-Activity of a Novel Chitobiase from a Psychrophilic Antarctic Bacterium
Lonhienne, T.; Zoidakis, J.; Vorgias, C. E. et al

in Journal of Molecular Biology (2001), 310(2), 291-7

The gene archb encoding for the cell-bound chitobiase from the Antarctic Gram-positive bacterium Arthrobacter sp. TAD20 was cloned and expressed in Escherichia coli in a soluble form. The mature ... [more ▼]

The gene archb encoding for the cell-bound chitobiase from the Antarctic Gram-positive bacterium Arthrobacter sp. TAD20 was cloned and expressed in Escherichia coli in a soluble form. The mature chitobiase ArChb possesses four functionally independent domains: a catalytic domain stabilized by Ca(2+), a galactose-binding domain and an immunoglobulin-like domain followed by a cell-wall anchorage signal, typical of cell-surface proteins from Gram-positive bacteria. Binding of saccharides was analyzed by differential scanning calorimetry, allowing to distinguish unequivocally the catalytic domain from the galactose-binding domain and to study binding specificities. The results suggest that ArChb could play a role in bacterium attachment to natural hosts. Kinetic parameters of ArChb demonstrate perfect adaptation to catalysis at low temperatures, as shown by a low activation energy associated with unusually low K(m) and high k(cat) values. Thermodependence of these parameters indicates that discrete amino acid substitutions in the catalytic center have optimized the thermodynamic properties of weak interactions involved in substrate binding at low temperatures. Microcalorimetry also reveals that heat-lability, a general trait of psychrophilic enzymes, only affects the active site domain of ArChb. [less ▲]

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See detailModularity of mind and the role of incentive motivation in representing novelty
Anselme, Patrick ULg

in Animal Cognition (2012), 15(4), 443-459

Animal and human brains contain a myriad of mental representations that have to be successfully tracked within fractions of a second in a large number of situations. This retrieval process is hard to ... [more ▼]

Animal and human brains contain a myriad of mental representations that have to be successfully tracked within fractions of a second in a large number of situations. This retrieval process is hard to explain without postulating the massive modularity of cognition. Assuming that the mind is massively modular, it is then necessary to understand how cognitive modules can efficiently represent dynamic environments – in which some modules may have to deal with change-induced novelty and uncertainty. Novelty of a stimulus is a problem for a module when unknown, significant stimuli do not satisfy the module’s processing criteria – or domain specificity – and cannot therefore be included in its database. It is suggested that the brain mechanisms of incentive motivation, recruited when faced with novelty and uncertainty, induce transient variations in the domain specificity of cognitive modules in order to allow them to process information they were not prepared to learn. It is hypothesised that the behavioural transitions leading from exploratory activity to habit formation are correlated with (and possibly caused by) the organism’s ability to counter novelty-induced uncertainty. [less ▲]

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See detailModulated misfit structure of the thermoelectric [Bi0.84CaO 2]2[CoO2]1.69 cobalt oxide
Muguerra, H.; Grebille, D.; Guilmeau, E. et al

in Inorganic Chemistry (2008), 47(7), 2464-2471

The structure of the thermoelectric lamellar misfit cobalt oxide [Bi 0.84CaO2]2[CoO2]1.69 has been refined using single crystal X-ray diffraction data. Using the four dimensional superspace formalism for ... [more ▼]

The structure of the thermoelectric lamellar misfit cobalt oxide [Bi 0.84CaO2]2[CoO2]1.69 has been refined using single crystal X-ray diffraction data. Using the four dimensional superspace formalism for aperiodic structures, the superspace group is confirmed P2/m(0δ1/2) (a1 = 4.9069(4), b1 = 4.7135(7), b2 = 2.8256(4), c1 = 14.668(5) Å, β1 = 93.32(1)°). The modulated displacements and site occupancies have been refined and are both compatible with the misfit character of the structure, and with a longitudinal modulation of the Bi-O layers of the structure. This modulation is similar to the corresponding one in the related Sr phase [Bi0.87SrO2]2[CoO2]1.82, but now oriented in the orthogonal direction. Because its incommensurate wavelength is locked with the aperiodicity of the misfit structure, it is possible to distinguish between the modulation parameters induced by the accommodation of both subsystems and those related to the longitudinal modulation of the Bi-O layers. In this original structure, two independent aperiodic phenomena coexist in an single crystallographic direction. A particular attention has been paid to the structural configuration of the CoO2 layer, in relation with other similar phases. The thermoelectric properties are probably directly related to the specific distortion of the compressed layer, but the different measured values for the Seebeck coefficient cannot be related to a significant modification of the CoO6 octahedra. © 2008 American Chemical Society. [less ▲]

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See detailModulating absorption and postprandial handling of dietary fatty acids by structuring fat in the meal : a randomized cross-over clinical trial
Vors, C; Pineau, G; Gabert, L et al

in American Journal of Clinical Nutrition (2013), 97(1), 23-36

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See detailModulating effect of COMT genotype on the brain regions underlying inhibition
Jaspar, Mathieu ULg; Grandjean, Julien ULg; Salmon, Eric ULg et al

Poster (2011, June 26)

Introduction Catechol-O-methytransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). Actually, a transition of ... [more ▼]

Introduction Catechol-O-methytransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). Actually, a transition of guanine to adenine at codon 158 of the COMT gene results in a valine to methionine substitution (Lotta & al., 1995). This phenomenon leads to different COMT genotypes, each associated with a different COMT enzymatic activity (Weinshilboum, & al., 1999). A large number of studies reported an effect of COMT on executive functioning. However, most of them used multi-determined executive tasks (e.g., Barnett & al., 2007). We are interested here to determine the effect of COMT Val158Met genotype on the activity of frontal and parietal areas (Nee & al., 2007; Laird & al., 2005) underlying the specific executive process of inhibition. Methods Procedure In an event-related fMRI experiment, a modified form of the Stroop task was administered to 44 young adults (age range: 18-30) separated into three groups according to their COMT Val158Met genotype: 15 homozygous val/val (VV), 14 homozygous met/met (MM) and 15 heterozygotes val/met (VM) carriers. The Stroop task consisted in the presentation of color words printed in various ink colors (e.g the word blue written in red). Subjects were instructed to name of ink color as fast and accurately as possible by avoiding to read the word. In this version of the Stroop task, three different contexts were created (data not showed here): (1) a congruent context (MC) with a majority of facilitator items (IC), (2) a non-congruent context (MI) with mainly interfering items (II), (3) a neutral context (MN) with mainly neutral items (IN, series of %%% written in different colors). MRI acquisition, data analysis Functional MRI time series were acquired on a 3T head-only scanner operated with the standard transmit-receive quadrature head coil. Multislice T2*-weighted functional images were acquired with a gradient-echo echo-planar imaging sequence using axial slice orientation and covering the whole brain (32 slices, FoV = 220x220 mm², voxel size 3.4x3.4x3 mm³, 30% interslice gap, matrix size 64x64x32, TR = 2130 ms, TE = 40 ms, FA = 90°). Structural images were obtained using a high resolution T1-weighted sequence (3D MDEFT [Deichmann & al., (2004)] ; TR = 7.92 ms, TE = 2.4 ms, TI = 910 ms, FA = 15°, FoV = 256 x 224 x 176 mm³, 1 mm isotropic spatial resolution). Preprocessing and statistical analyses were performed with SPM8 (p<.001 uncorrected). Results Behavioral results indicated the presence of a general interference effect (II – IN items) for reaction time (F(1,41) = 292,44 ; p < 0,001) but no significant difference in interference between the three groups (F(2,41) = 0,27; p = 0,76). FMRI results revealed that interference effect [(MI_II-MI_IN) + (MC_II-MC_IN) + (MN_II-MN_IN)] observed in our three groups is mainly associated with cerebral activity in frontal and parietal areas. Moreover, group comparisons indicates that this effect is associated with increased medial frontal and precentral gyrus activity in VV and VM groups by comparison with MM group, but also in the superior temporal gyrus and in the thalamus in the VM by comparison to MM . Conversely, no supplementary brain area was observed for the comparison of the MM to the two other groups. Conclusions The fronto-parietal brain network associated with interference resolution observed here is consistent with prior reports (Nee & al., 2007; Laird & al., 2005). Moreover, results showed activity in different brain areas according to the COMT genotype. Indeed, a similar behavioral performance is associated to the recruitment of supplementary areas in the carriers of the val allele. This observation, paralleling with the lower COMT enzymatic activity and, thus, the higher cortical dopamine level in met/met individuals, confirms our expectation of a COMT Val158Met genotype modulation of the brain regions underlying inhibition efficiency. [less ▲]

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See detailModulating effect of COMT genotype on the brain regions underlying proactive control process during inhibition
Jaspar, Mathieu ULg; Genon, Sarah ULg; Muto, Vincenzo ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2014), 50

Introduction. Genetic variability related to the catechol-O-methyltransferase (COMT) gene (Val158Met polymorphism) has received increasing attention as a possible modulator of cognitive control functions ... [more ▼]

Introduction. Genetic variability related to the catechol-O-methyltransferase (COMT) gene (Val158Met polymorphism) has received increasing attention as a possible modulator of cognitive control functions. Methods. In an event-related fMRI study, a modified version of the Stroop task was administered to three groups of 15 young adults according to their COMT Val158Met genotype [Val/Val (VV), Val/Met (VM) and Met/Met (MM)]. Based on the theory of dual mechanisms of control (Braver, et al., 2007), the Stroop task has been built to induce proactive or reactive control processes according to the task context. Results. Behavioral results did not show any significant group differences for reaction times but Val allele carriers individuals are less accurate in the processing of incongruent items. fMRI results revealed that proactive control is specifically associated with increased activity in the anterior cingulate cortex (ACC) in carriers of the Met allele, while increased activity is observed in the middle frontal gyrus (MFG) in carriers of the Val allele. Conclusion. These observations, in keeping with a higher cortical dopamine level in MM individuals, support the hypothesis of a COMT Val158Met genotype modulation of the brain regions underlying proactive control, especially in frontal areas as suggested by Braver et al. [less ▲]

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See detailModulating effect of COMT genotype on the brains regions underlying inhibition
Jaspar, Mathieu ULg; Grandjean, Julien ULg; SALMON, Eric ULg et al

Conference (2012, May)

Catechol-O-methyltransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). A large number of studies reported an ... [more ▼]

Catechol-O-methyltransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). A large number of studies reported an effect on executive functioning of COMT genotype (Barnett & al., 2007), each genotype being associated with a different COMT enzymatic activity (Weinshilboum & al., 1999). In an event-related fMRI study, a modified form of the Stroop task was administered to 45 young adults separated in three groups according to their COMT val158met genotype : 15 homozygous val/val (VV), 15 homozygous met/met (MM) and 15 heterozygotes val/met (VM). Both behavioral and fMRI results indicated the presence of a general interference effect consistent with prior reports (Nee & al., 2007). More interestingly, group comparisons indicate that this effect is associated, for a similar behavioral performance, with increased medial frontal and precentral gyrus activity in VV and VM groups by comparison with MM group. Conversely, no supplementary brain areas were observed for the comparison of the MM to the two other groups. These observations, paralleling with the lower COMT enzymatic activity and, thus, the higher cortical dopamine level in met/met individuals, confirms our expectation of a COMT Val158Met genotype modulation of the brain regions underlying inhibition efficiency. [less ▲]

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