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Peer Reviewed
See detailProbable microfossils in 3.2 Ga-old shallow-water siliciclastic deposits
Javaux, Emmanuelle ULg; Marshall, Craig; Bekker, Andrey

Conference (2008)

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See detailProbing a molecular electronic transition by two-colour sum-frequency generation spectroscopy
Humbert, Christophe; Dreesen, Laurent ULg; Nihonyanagi, S. et al

in Applied Surface Science (2003), 212–213

We demonstrate that a new emerging technique, two-colour sum-frequency generation (SFG) spectroscopy, can be used to probe the molecular electronic properties of self-assembled monolayers (SAMs). In the ... [more ▼]

We demonstrate that a new emerging technique, two-colour sum-frequency generation (SFG) spectroscopy, can be used to probe the molecular electronic properties of self-assembled monolayers (SAMs). In the CH spectral range (2800–3200 cm-1), we show that the sum-frequency generation signal of a porphyrin alkanethiol derivative adsorbed on Pt(1 1 1) reaches a maximum intensity at ~435 nm SFG wavelength. This wavelength corresponds to the porphyrin moiety specific p–p*$ molecular electronic transition which is called the Soret or B band. This resonant behaviour is not observed for 1-dodecanethiol SAMs, which are devoid of molecular electronic transition in the investigated visible spectral range. [less ▲]

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See detailProbing command following in patients with disorders of consciousness using a brain-computer interface
Noirhomme, Quentin ULg; Chatelle, Camille ULg; Kleih, Sonja et al

Conference (2010, June)

Objective: In the recovery from coma, the acquisition of command following represents an important milestone, indicating emergence from the vegetative state. In some patients, recovery of consciousness ... [more ▼]

Objective: In the recovery from coma, the acquisition of command following represents an important milestone, indicating emergence from the vegetative state. In some patients, recovery of consciousness may precede motor recovery. Brain-computer interfaces (BCI) might permit these patients to show non-motor dependent signs of awareness and in a next step might enable communication. This study aimed at testing to what extent an EEG-based BCI could help detecting signs of awareness and communication in disorders of consciousness. Methods: We studied 13 patients with a minimally conscious state (MCS, 5 TBI – 8 anoxic, mean time post injury 70±109 months; mean age 42 ± 21) and 16 healthy controls (aged 45±19). Patients were evaluated using the Coma Recovery Scale Revised. 16-Channel EEG was recorded using a g.tec USBAmp amplifier. An auditory P300 four choice speller paradigm based on the BCI2000 system was used. Subjects were asked to answer yes or no to simple questions by paying attention to one out of four auditorily presented stimuli (‘yes’, ‘no’, ‘stop’, ‘go’). A trial constituted of 15 presentations of each sound the order of presentation being randomized. After a training session, patients and healthy subjects were required to answer 10 to 12 questions. A stepwise linear discriminant analysis based on the training session was used to classify the data. Offline, all training and testing trials were pooled and a leave-one-out approach was used to classify the data. Results: Healthy subjects presented a mean correct response rate of 73% online and 93% offline. Three MCS patients had a correct response rate of ≥50% offline (10, 18, 0% online and 50, 53, 57% offline). Two of these three patients did not show any command following at the bedside. The 10 remaining MCS cases showed online and offline correct answers <50% (mean 33±9% online and 25±13% offline). Conclusion: Our auditory P300-based BCI permitted functional interactive communication in 15/16 controls (online) and in all offline. Our data obtained in patients with disorders of consciousness demonstrate the potential clinical usefulness of the technique following coma but also show lower accuracy in patients as compared to healthy volunteers. This might be due to fluctuating attentional levels and exhaustibility in the MCS and to the suboptimal EEG recording quality due to movement, ocular and respiration artifacts in these challenging patients. [less ▲]

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See detailProbing command following in patients with disorders of consciousness using a brain-computer interface.
Lule, Dorothee; Noirhomme, Quentin ULg; Kleih, Sonja C. et al

in Clinical Neurophysiology (2013), 124(1), 101-6

OBJECTIVE: To determine if brain-computer interfaces (BCIs) could serve as supportive tools for detecting consciousness in patients with disorders of consciousness by detecting response to command and ... [more ▼]

OBJECTIVE: To determine if brain-computer interfaces (BCIs) could serve as supportive tools for detecting consciousness in patients with disorders of consciousness by detecting response to command and communication. METHODS: We tested a 4-choice auditory oddball EEG-BCI paradigm on 16 healthy subjects and 18 patients in a vegetative state/unresponsive wakefulness syndrome, in a minimally conscious state (MCS), and in locked-in syndrome (LIS). Subjects were exposed to 4 training trials and 10 -12 questions. RESULTS: Thirteen healthy subjects and one LIS patient were able to communicate using the BCI. Four of those did not present with a P3. One MCS patient showed command following with the BCI while no behavioral response could be detected at bedside. All other patients did not show any response to command and could not communicate with the BCI. CONCLUSION: The present study provides evidence that EEG based BCI can detect command following in patients with altered states of consciousness and functional communication in patients with locked-in syndrome. However, BCI approaches have to be simplified to increase sensitivity. SIGNIFICANCE: For some patients without any clinical sign of consciousness, a BCI might bear the potential to employ a "yes-no" spelling device offering the hope of functional interactive communication. [less ▲]

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See detailProbing conductivity fluctuations in high critical temperature superconductors
Ausloos, Marcel ULg; Clippe, Paulette ULg; Laurent, Christian

in Solid State Communications (1990), 73(2), 137-141

We comment and discuss published data on the electrical resistivity of high temperature superconductors in order to extract the dimensionality of superconductivity "critical" fluctuations. We present ... [more ▼]

We comment and discuss published data on the electrical resistivity of high temperature superconductors in order to extract the dimensionality of superconductivity "critical" fluctuations. We present arguments which indicate that observation of three temperature regimes is indeed possible: a scaling regime close to Tc and two regimes in the mean field region. In each regime, dominant scattering mechanisms can be different. [less ▲]

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See detailProbing fluoroquinoone-biomembrane interactions on the nanoscale
Fa, Nathalie; Burton, Ingrid; Deleu, Magali ULg et al

Poster (2005)

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See detailProbing Ligand–Protein Recognition with Sum-Frequency Generation Spectroscopy: The Avidin–Biocytin Case
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2004), 5

Infrared/visible sum-frequency generation (SFG) spectroscopy is used to study the recognition of a protein (avidin) by a derived vitamin (biocytin) adsorbed on a calcium fluoride substrate. The ... [more ▼]

Infrared/visible sum-frequency generation (SFG) spectroscopy is used to study the recognition of a protein (avidin) by a derived vitamin (biocytin) adsorbed on a calcium fluoride substrate. The specificity of the process is tested by replacing avidin with bovine serum albumin or presaturated avidin. The SFG spectroscopy shows drastic modifications in the CH and NH spectral ranges only upon exposure of the biocytin film to avidin. The comparison of the SFG data with Fourier transform infrared reflection absorption spectra (FT-IRRAS) in the same spectral ranges illustrates the advantages of nonlinear spectroscopy for studying and detecting recognition between biomolecules. [less ▲]

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See detailProbing liquid-mirror surface quality using the CCD triangulation technique
Finet, François; Surdej, Jean ULg

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2013)

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See detailProbing of Actinobacillus pleuropneumoniae ApxIIIA toxin-dependent cytotoxicity towards mammalian peripheral blood mononucleated cells
Vanden Bergh, Philippe ULg; Zecchinon, Laurent ULg; Fett, Thomas ULg et al

in BMC Research Notes (2008)

BACKGROUND: Actinobacillus pleuropneumoniae, the causative bacterial agent of porcine pleuropneumonia, produces Apx toxins which belong to RTX toxin family and are recognized as the major virulence ... [more ▼]

BACKGROUND: Actinobacillus pleuropneumoniae, the causative bacterial agent of porcine pleuropneumonia, produces Apx toxins which belong to RTX toxin family and are recognized as the major virulence factors. So far, their target receptor(s) has not been identified and the disease cytopathogenesis remains poorly understood. Production of an active Apx toxin and characterization of its toxic activity constitute the premises necessary to the description of its interaction with a potential receptor. From this point of view, we produced an active recombinant ApxIIIA toxin in order to characterize its toxicity on peripheral blood mononucleated cells (PBMCs) isolated from several species. FINDINGS: Toxin preparation exercises a strong cytotoxic action on porcine PBMCs which is directly related to recombinant ApxIIIA since preincubation with polymyxin B does not modify the cytotoxicity rate while preincubation with a monospecific polyclonal antiserum directed against ApxIIIA does. The cell death process triggered by ApxIIIA is extremely fast, the maximum rate of toxicity being already reached after 20 minutes of incubation. Moreover, ApxIIIA cytotoxicity is species-specific because llama, human, dog, rat and mouse PBMCs are resistant. Interestingly, bovine and caprine PBMCs are slightly sensitive to ApxIIIA toxin too. Finally, ApxIIIA cytotoxicity is cell type-specific as porcine epithelial cells are resistant. CONCLUSION: We have produced an active recombinant ApxIIIA toxin and characterized its specific cytotoxicity on porcine PBMCs which will allow us to get new insights on porcine pleuropneumonia pathogenesis in the future. [less ▲]

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See detailProbing of the reaction progress at a PMMA/PS interface by using anthracene-labeled reactive PS chains
Yin, Zhihui; Koulic, Christian; Pagnoulle, Christophe et al

in Langmuir (2003), 19(2), 453-457

The progress of the interfacial reaction of polystyrene chains end-capped by a primary amine (PS-NH2) and PMMA chains end-capped by an anhydride (PMMA-anh) has been monitored by SEC-UV, by using ... [more ▼]

The progress of the interfacial reaction of polystyrene chains end-capped by a primary amine (PS-NH2) and PMMA chains end-capped by an anhydride (PMMA-anh) has been monitored by SEC-UV, by using anthracene-labeled polystyrene chains (anth-PS-NH2) as a probe. Assemblies of an anth-PS-NH2 layer and a PMMA-anh layer were annealed at 200 degreesC for various periods of time. The interfacial reaction rate depends on the molecular weight (MW) of the reactive precursors in relation to the gammaN value of the chains. For chains of low gammaN (chiN = 6), the reaction is faster because the interface becomes more diffuse with time, as observed by TEM and AFM, consistent with compatibilization of the weakly immiscible polymers by the copolymer formed in-situ. For chains of higher molecular weight and chiN (10, instead of 6), the interface is much sharper and the residence time at the interface of the symmetric diblock copolymer of higher molecular weight is also increased, which dramatically restricts the progress of the interfacial reaction under the annealing conditions used in this work. [less ▲]

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See detailProbing Organization and Structural Characteristics of Alkanethiols Adsorbed on Gold and of Model Alkane Compounds through their Valence Electronic Structure: an Ultraviolet Photoelectron Spectroscopy Study
Duwez, Anne-Sophie ULg; Pfister-Guillouzo, G.; Delhalle, Joseph et al

in Journal of Physical Chemistry B (2000), 104

In this paper we report an ultraviolet photoelectron spectroscopy (UPS) study of saturated alkane chains in various configurations and conformations. The dependence of the valence spectra on molecular ... [more ▼]

In this paper we report an ultraviolet photoelectron spectroscopy (UPS) study of saturated alkane chains in various configurations and conformations. The dependence of the valence spectra on molecular structure characteristics has been assessed by comparing the results obtained from n-alkanethiol, R,ö-alkanedithiol, and R-cycloalkyl-ö-alkanethiol monolayers adsorbed on gold, and from gas-phase model alkane compounds. The differences between the spectra reflect directly the structural changes induced in the electronic structure of the alkane chains. We have determined the type of folding sequences adopted in a 1,12-dodecanedithiol monolayer. Angular dependent measurements and investigations on the photoelectron attenuation length have evidenced very fine structural differences between films obtained on deposited gold films, annealed gold films, and gold single crystals [less ▲]

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See detailProbing Peptide-Membrane Interactions Using Afm
Brasseur, Robert ULg; Deleu, Magali ULg; Mingeot-Leclercq, Mp. et al

in Surface and Interface Analysis [=SIA] (2008), 40(3-4), 151-156

Atomic force microscopy (AFM) has become a powerful addition to the range of instruments available to probe the organization of lipid monolayers and bilayers. Currently, AFM is the only tool that can ... [more ▼]

Atomic force microscopy (AFM) has become a powerful addition to the range of instruments available to probe the organization of lipid monolayers and bilayers. Currently, AFM is the only tool that can provide nanoscale topographic images of supported lipid membranes under physiological conditions, enabling researchers to resolve their detailed structure and to monitor their interaction with drugs, peptides and proteins. Here, we survey recent data obtained by our research groups that demonstrate the power of the technique for exploring peptide–membrane interactions, with an emphasis on microbial lipopeptides and on tilted peptides. [less ▲]

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See detailProbing populations of red giants in the galactic disk with CoRoT
Miglio, Andrea ULg; Montalban Iglesias, Josefa ULg; Baudin, F. et al

in Astronomy and Astrophysics (2009), 503

Context: The detection with CoRoT of solar-like oscillations in nearly 800 red giants in the first 150-days long observational run paves the way for detailed studies of populations of galactic-disk red ... [more ▼]

Context: The detection with CoRoT of solar-like oscillations in nearly 800 red giants in the first 150-days long observational run paves the way for detailed studies of populations of galactic-disk red giants. <BR />Aims: We investigate which information on the observed population can be recovered by the distribution of the observed seismic constraints: the frequency of maximum oscillation power (ν_max) and the large frequency separation (Δν). <BR />Methods: We propose to use the observed distribution of ν_max and of Δν as a tool for investigating the properties of galactic red-giant stars through comparison with simulated distributions based on synthetic stellar populations. <BR />Results: We can clearly identify the bulk of the red giants observed by CoRoT as red-clump stars, i.e. post-flash core-He-burning stars. The distribution of ν_max and of Δν gives us access to the distribution of the stellar radius and mass, and thus represent a most promising probe of the age and star formation rate of the disk, and of the mass-loss rate during the red-giant branch. <BR />Conclusions: CoRoT observations are supplying seismic constraints for the most populated class of He-burning stars in the galactic disk. This opens a new access gate to probing the properties of red-giant stars that, coupled with classical observations, promises to extend our knowledge of these advanced phases of stellar evolution and to add relevant constraints to models of composite stellar populations in the Galaxy. The CoRoT space mission was developed and is operated by the French space agency CNES, with the participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. [less ▲]

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See detailProbing rapidly ionzing super-atom molecular orbitals (SAMO) in fullerenes
Mignolet, Benoît ULg

Scientific conference (2013, May 29)

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See detailProbing Rapidly-Ionizing Super-Atom Molecular Orbitals in C60: A Computational and Femtosecond Photoelectron Spectroscopy Study
Mignolet, Benoît ULg; Johansson, Olof; Campbell, Eleanor E. B. et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2013)

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See detailProbing recognition processes, forces and motions within single molecules
Willet, Nicolas ULg

Scientific conference (2011, June)

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See detailProbing recognition processes, forces and motions within single molecules
Willet, Nicolas ULg; Duwez, Anne-Sophie ULg

Scientific conference (2012, May 09)

Detailed reference viewed: 7 (0 ULg)