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See detailElectrophysiological investigations of brain function in coma, vegetative and minimally conscious patients.
Lehembre, Remy ULg; Gosseries, Olivia ULg; Lugo, Zulay et al

in Archives Italiennes de Biologie (2012), 150(2-3), 122-39

Electroencephalographic activity in the context of disorders of consciousness is a swiss knife like tool that can evaluate different aspects of cognitive residual function, detect consciousness and ... [more ▼]

Electroencephalographic activity in the context of disorders of consciousness is a swiss knife like tool that can evaluate different aspects of cognitive residual function, detect consciousness and provide a mean to communicate with the outside world without using muscular channels. Standard recordings in the neurological department offer a first global view of the electrogenesis of a patient and can spot abnormal epileptiform activity and therefore guide treatment. Although visual patterns have a prognosis value, they are not sufficient to provide a diagnosis between vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious state (MCS) patients. Quantitative electroencephalography (qEEG) processes the data and retrieves features, not visible on the raw traces, which can then be classified. Current results using qEEG show that MCS can be differentiated from VS/UWS patients at the group level. Event Related Potentials (ERP) are triggered by varying stimuli and reflect the time course of information processing related to the stimuli from low-level peripheral receptive structures to high-order associative cortices. It is hence possible to assess auditory, visual, or emotive pathways. Different stimuli elicit positive or negative components with different time signatures. The presence of these components when observed in passive paradigms is usually a sign of good prognosis but it cannot differentiate VS/UWS and MCS patients. Recently, researchers have developed active paradigms showing that the amplitude of the component is modulated when the subject's attention is focused on a task during stimulus presentation. Hence significant differences between ERPs of a patient in a passive compared to an active paradigm can be a proof of consciousness. An EEG-based brain-computer interface (BCI) can then be tested to provide the patient with a communication tool. BCIs have considerably improved the past two decades. However they are not easily adaptable to comatose patients as they can have visual or auditory impairments or different lesions affecting their EEG signal. Future progress will require large databases of resting state-EEG and ERPs experiment of patients of different etiologies. This will allow the identification of specific patterns related to the diagnostic of consciousness. Standardized procedures in the use of BCIs will also be needed to find the most suited technique for each individual patient. [less ▲]

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See detailElectrophysiological monitoring in clinical trials
Bril, Valérie; Ellison, R.; Ngo, Marguerite et al

in Muscle & Nerve (1998)

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See detailElectrophysiological response patterns of primary sensory cortices in migraine.
Ambrosini, Anna; Schoenen, Jean ULg

in Journal of Headache & Pain (2006), 7(6), 377-88

Migraine is an ictal disorder characterised by a particular vulnerability of patients to sensory overload, both during and outside of the attack. Central nervous system dysfunctions are supposed to play a ... [more ▼]

Migraine is an ictal disorder characterised by a particular vulnerability of patients to sensory overload, both during and outside of the attack. Central nervous system dysfunctions are supposed to play a pivotal role in migraine. Electroneurophysiological methods, which aim to investigate sensory processing, seem thus particularly appropriate to study the pathophysiology of migraine. We have thus reviewed evoked potential studies performed in migraine patients. Although results are in part contradictory, these studies nonetheless demonstrate an interictal dysfunction of sensory cortices, and possibly of subcortical structures, in migraine with and without aura. The predominant abnormality is a deficient habituation of evoked responses to repeated stimuli, probably due to cortical, and possibly widespread neural, "dysexcitability". [less ▲]

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See detailElectrophysiological studies in migraine: a comprehensive review of their interest and limitations
Ambrosini, Anna; Maertens De Noordhout, Alain ULg; Sandor, P. et al

in Cephalalgia : An International Journal of Headache (2003), 23(Suppl. 1), 13-31

Electrophysiological methods may help to unravel some of the pathophysiological mechanisms of migraine. Lack of habituation is the principal and most reproducible interictal abnormality in sensory ... [more ▼]

Electrophysiological methods may help to unravel some of the pathophysiological mechanisms of migraine. Lack of habituation is the principal and most reproducible interictal abnormality in sensory processing in migraineurs. It is found in evoked potential (EP) studies for every stimulation modality including nociceptive stimuli, and it is likely to be responsible for the increased intensity dependence of EP. We have hypothesized that deficient EP habituation in migraine could be due to a reduced preactivation level of sensory cortices because of hypofunctioning subcortico-cortical aminergic pathways. This is not in keeping with simple hyperexcitability of the cortex, which has been suggested by some, but not all, studies of transcranial magnetic stimulation (TMS). A recent study of the effects of repetitive TMS on visual EP strongly supports the hypothesis that migraine is characterized by interictal cortical hypoexcitability. With regard to pain mechanisms in migraine, electrophysiological studies of trigeminal pathways using nociceptive blink and corneal reflexes have confirmed that sensitization of central trigeminal nociceptors occurs during migraine attacks. [less ▲]

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See detailElectrophysiological study of central mechanisms of fatigue in multiple sclerosis.
DELVAUX, Valérie ULg; THIBAUT V.; GERARDY P.Y. et al

in Clinical Neurophysiology (2000, August), 111(Suppl. 1), 12316-05

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See detailElectrophysiologie des états de conscience altérée
Noirhomme, Quentin ULg; Lehembre, Remy ULg

in Schnakers, Caroline; Laureys, Steven (Eds.) Coma et états de conscience altérée (2011)

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See detailElectrophysiology and disorders of consciousness
Noirhomme, Quentin ULg; Lehembre, Remy ULg

in Schnakers, Caroline; Laureys, Steven (Eds.) Coma and disorders of consciousness (2012)

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See detailThe electrophysiology of migraine
Ambrosini, A.; Schoenen, Jean ULg

in Current Opinion in Neurology (2003), 16(3), 327-331

Purpose of review The pathophysiology of migraine is far from being understood. Electrophysiological methods are useful to investigate peripheral and central mechanisms underlying this disorder. The ... [more ▼]

Purpose of review The pathophysiology of migraine is far from being understood. Electrophysiological methods are useful to investigate peripheral and central mechanisms underlying this disorder. The purpose of this review is to highlight the results of electrophysiological studies published during the last year and to examine their added value to our previous knowledge. Recent findings Studies by visual and auditory evoked potentials and event-related responses suggested that lack of habituation is the principal interictal abnormality of sensory processing in migraineurs. Recently confirmed for somatosensory and laser-evoked cortical potentials and for brainstem responses, it is also responsible for the increased intensity dependence of auditory evoked potentials. This abnormality is possibly caused by a reduced cortical preactivation level due to hypofunctioning subcortico-cortical aminergic pathways. Although studies of cortical excitability by transcranial magnetic stimulation have yielded conflicting results, results obtained using habituation of pattern-reversal visual evoked potentials to explore cortical excitability changes induced by repetitive transcranial magnetic stimulation strongly favour the hypothesis that migraine is characterized by a decreased level of preactivation excitability. With regard to pain mechanisms in migraine, electrophysiological studies of trigeminal pathways using nociceptive blink and corneal reflexes have confirmed that sensitization of central trigeminal nociceptors occurs during the attack, and may even persist interictally. Summary Scientific publications over the last year confirmed that electrophysiological methods are particularly suited to unravelling some of the pathophysiological mechanisms of migraine. To improve their future contribution, they need to be better standardized and to be correlated with behavioural, metabolic and genetic studies. [less ▲]

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See detailThe electroreduction of acrylonitrile : a new insight into the mechanism
Mertens, Marc; Calberg, Cédric ULg; Martinot, Lucien et al

in Macromolecules (1996), 29(14), 4910-4918

Several complementary electrochemical techniques have been used in order to clear up the mechanism of the electrochemical reduction of acrylonitrile (AN) on nickel. According to Lecayon et al., the ... [more ▼]

Several complementary electrochemical techniques have been used in order to clear up the mechanism of the electrochemical reduction of acrylonitrile (AN) on nickel. According to Lecayon et al., the electropolymerization of AN occurs in acetonitrile in the presence of tetraethylammonium perchlorate in such a way that polyacrylonitrile (PAN) is “grafted” onto the cathode. This electrochemical reaction has been reinvestigated both in acetonitrile, a nonsolvent of PAN, and in N,N-dimethylformamide (DMF), a good solvent for the polymer. The key role of the reduction potential on the electrografting reaction has been emphasized. The two electrochemical phenomena previously reported by Lecayon et al. have indeed been confirmed, but now it is clear that the “electrografting” of PAN selectively occurs at the less cathodic potential. At this potential, a PAN film is formed by a radical process and firmly secured onto the electrode, even in DMF. If the cathodic potential is further increased, the PAN film is easily removed from the metal and dissolves quickly in DMF. The transfer of one electron from the metal to the monomer occurs when the reduction is carried out at the more cathodic potential. A nonadherent PAN film is then formed onto Ni in acetonitrile, although the AN polymerization occurs in solution when acetonitrile is replaced by DMF. The AN polymerization is then consistent with an anionic process. [less ▲]

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See detailElectroresistance Effect in Ferroelectric Tunnel Junctions with Symmetric Electrodes
Bilc, Daniel ULg; Novaes, F. D.; Iniguez, J. et al

in ACS Nano (2012), 6(2), 1473-1478

Understanding the effects that govern electronic transport in ferroelectric tunnel junctions (FTJs) is of vital importance to improve the efficiency of devices such as ferroelectric memories with ... [more ▼]

Understanding the effects that govern electronic transport in ferroelectric tunnel junctions (FTJs) is of vital importance to improve the efficiency of devices such as ferroelectric memories with nondestructive readout. However, our current knowledge (typically based on simple semiempirical models or first-principles calculations restricted to the limit of zero bias) remains partial, which may hinder the development of more efficient systems. For example, nowadays it is commonly believed that the tunnel electroresistance (TER) effect exploited in such devices mandatorily requires, to be sizable, the use of two different electrodes, with related potential drawbacks concerning retention time, switching, and polarization imprint. In contrast, here we demonstrate at the first-principles level that large TER values of about 200% can be achieved under finite bias in a prototypical FTJ with symmetric electrodes. Our atomistic approach allows us to quantify the contribution of different microscopic mechanisms to the electroresistance, revealing the dominant role of the inverse piezoelectric response of the ferroelectric. On the basis of our analysis, we provide a critical discussion of the semiempirical models traditionally used to describe FTJs. [less ▲]

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See detailElectrospinning and nanofibers
Sorlier, Pierre; Grignard, Bruno ULg; Mitu, Alina et al

Poster (2007, August 31)

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See detailElectrospinning of a functional perfluorinated block copolymer as a powerful route for imparting superhydrophobicity and corrosion resistance to aluminum substrates
Grignard, Bruno ULg; Vaillant, Alexandre; de Coninck, Joel et al

in Langmuir (2011), 27(1), 335-342

Superhydrophobic aluminum surfaces with excellent corrosion resistance were successfully prepared by electrospinning of a novel fluorinated diblock copolymer solution. Micro- and nanostructuration of the ... [more ▼]

Superhydrophobic aluminum surfaces with excellent corrosion resistance were successfully prepared by electrospinning of a novel fluorinated diblock copolymer solution. Micro- and nanostructuration of the diblock copolymer coating was obtained by electrospinning which proved to be an easy and cheap electrospinning technology to fabricate superhydrophobic coating. The diblock copolymer is made of poly(heptadecafluorodecylacrylate-co-acrylic acid) (PFDA-co-AA) random copolymer as the first block and polyacrylonitrile (PAN) as the second one. The fluorinated block promotes hydrophobicity to the surface by reducing the surface tension, while its carboxylic acid functions anchor the polymer film onto the aluminum surface after annealing at 130 °C. The PAN block of this copolymer insures the stability of the structuration of the surface during annealing, thanks to the infusible character of PAN. It is also demonstrated that the so-formed superhydrophobic coating shows good adhesion to aluminum surfaces, resulting in excellent corrosion resistance. [less ▲]

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See detailElectrospinning of biocompatible polymers for potential biomdical applications
Croisier, Florence ULg; Zalfen, Alina; Aqil, Abdelhafid ULg et al

Poster (2008, June 23)

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See detailElectrospray mass spectrometry of noncovalent complexes between small molecule ligands and nucleic acids
Gabelica, Valérie ULg

in Joseph H., Banoub; Patrick A., Limbach (Eds.) Mass spectrometry of nucleosides and nucleic acids (2010)

CONTENTS 8.1 Introduction 8.1.1 ESI-MS of Noncovalent Complexes 8.1.2 Nucleic Acid Targeting by Small Molecules 8.2 Electrospray Mass Spectrometry of Nucleic Acid Noncovalent Complexes 8.2.1 ... [more ▼]

CONTENTS 8.1 Introduction 8.1.1 ESI-MS of Noncovalent Complexes 8.1.2 Nucleic Acid Targeting by Small Molecules 8.2 Electrospray Mass Spectrometry of Nucleic Acid Noncovalent Complexes 8.2.1 Stoichiometries: Number of Strands and Detection of Nucleic Acid Higher-Order Structures 8.2.2 Stoichiometries: Number of Bound Ligands 8.2.3 Role of Cations in Nucleic Acid Structure and Ligand Binding 8.2.4 Determination of Equilibrium Binding Constants 8.2.5 Are the Relative Intensities Proportional to the Abundances in Solution? 8.3 Characterizing Noncovalent Ligand Binding by MS/MS of the Complexes 8.3.1 Overview of Dissociation Pathways 8.3.2 How Observed Pathways Depend on Instrumental Parameters 8.3.3 How Observed Pathways Depend on Ligand Binding 8.3.4 Probing the Energetics of Ligand-DNA Interactions 8.3.5 Determining the Ligand Binding Mode 8.3.6 Determining the Ligand Binding Site by MS/MS 8.4 Conclusion and Outlook References [less ▲]

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See detailElectrospray Mass Spectrometry of Telomeric RNA (TERRA) Reveals the Formation of Stable Multimeric G-Quadruplex Structures
Collie, Gavin W.; Parkinson, Gary N.; Neidle, Stephen et al

in Journal of the American Chemical Society (2010), 132(27), 93289334

We report on the self-assembled structures formed by 12-mer, 22-mer, and 45-mer telomeric RNA (telRNA/TERRA) sequences compared to their DNA analogues, as studied by electrospray mass spectrometry ... [more ▼]

We report on the self-assembled structures formed by 12-mer, 22-mer, and 45-mer telomeric RNA (telRNA/TERRA) sequences compared to their DNA analogues, as studied by electrospray mass spectrometry, circular dichroism, and thermal denaturation. The major difference between telomeric RNA and DNA sequences is the ability of telomeric RNA to form higher-order dimeric assemblies, initiated by cation-mediated stacking of two parallel G-quadruplex subunits. The 5′-5′ stacking had been observed recently by NMR for the r(GGGUUAGGGU) 10-mer (Martadinata, H.; Phan, A. T. J. Am. Chem. Soc. 2009, 131, 2570); the present work shows that stacking also occurs for the 22-mer containing four G-tracts and for the 45-mer containing eight G-tracts, suggesting a general structural feature of telomeric RNA. The importance of kinetic effects in multimer formation, unfolding, and structural rearrangements is also highlighted. [less ▲]

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See detailElectrospray Mass Spectrometry Study of Selective Complexes of Polyammonium Macrotricyclic Ligands with Dicarboxylic Acids
Collette, Caroline ULg; Meunier, Cécile; De Pauw, Edwin ULg et al

in Rapid Communications in Mass Spectrometry : RCM (1997), 11

Macrocyclic and macropolycyclic polyammonium host molecules have been shown to complex a variety of inorganic and organic anions strongly and selectively. The selectivity of the complexation depends on ... [more ▼]

Macrocyclic and macropolycyclic polyammonium host molecules have been shown to complex a variety of inorganic and organic anions strongly and selectively. The selectivity of the complexation depends on the substrate lenght and on the size of the host cavity of the macrocycle. We describe in this article the analysis of the complexation of dicarboxylic acid substrates by a macrotricyclic host using electrospray mass spectrometry. [less ▲]

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See detailElectrospray Mass Spectrometry to Study Drug-Nucleic Acids Interactions
Rosu, Frédéric ULg; De Pauw, Edwin ULg; Gabelica, Valérie ULg

in Biochimie (2008), 90(7), 1074-1087

We present here a tutorial review on the electrospray mass spectrometry technique and its applications to the study of drug-nucleic acid non-covalent complexes. Particular emphasis has been made on the ... [more ▼]

We present here a tutorial review on the electrospray mass spectrometry technique and its applications to the study of drug-nucleic acid non-covalent complexes. Particular emphasis has been made on the basic principles of the technique, to allow even the non-specialist to design fit-for-purpose mass spectrometry experiments and interpret the results. Standard applications will be described in detail, including the determination of stoichiometries and equilibrium binding constants of non-covalent complexes, the study of binding kinetics, and the development of ligand screening assays. We also outline the potentials of more advanced and/or more recent MS-based techniques (tandem mass spectrometry, ion mobility spectrometry and gas-phase spectroscopy) for the study of the nucleic acid-ligand complexes. [less ▲]

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See detailElectrostatic analysis of moving conductors using a finite element perturbation method
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Proceedings of the 13th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2008) (2008, May)

Detailed reference viewed: 39 (20 ULg)