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See detailLow-Molecular-Weight Protein Tyrosine Phosphatases of Bacillus subtilis
Musumeci, Lucia ULiege; Bongiorni, Cristina; Tautz, Lutz et al

in Journal of Bacteriology (2005), 187(14), 4945-4956

In gram-negative organisms, enzymes belonging to the low-molecular-weight protein tyrosine phosphatase (LMPTP) family are involved in the regulation of important physiological functions, including stress ... [more ▼]

In gram-negative organisms, enzymes belonging to the low-molecular-weight protein tyrosine phosphatase (LMPTP) family are involved in the regulation of important physiological functions, including stress resistance and synthesis of the polysaccharide capsule. LMPTPs have been identified also in gram-positive bacteria, but their functions in these organisms are presently unknown. We cloned two putative LMPTPs from Bacillus subtilis, YfkJ and YwlE, which are highly similar to each other in primary structure as well as to LMPTPs from gram-negative bacteria. When purified from overexpressing Escherichia coli strains, both enzymes were able to dephosphorylate p-nitrophenyl-phosphate and phosphotyrosine-containing substrates in vitro but showed significant differences in kinetic parameters and sensitivity to inhibitors. Transcriptional analyses showed that yfkJ was transcribed at a low level throughout the growth cycle and underwent a σB-dependent transcriptional upregulation in response to ethanol stress. The transcription of ywlE was growth dependent but stress insensitive. Genomic deletion of each phosphatase-encoding gene led to a phenotype of reduced bacterial resistance to ethanol stress, which was more marked in the ywlE deletion strain. Our study suggests that YfkJ and YwlE play roles in B. subtilis stress resistance. [less ▲]

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See detailLow-order local modelling of structural nonlinearities
Noël, Jean-Philippe ULiege; Kerschen, Gaëtan ULiege

in Proceedings of the XVIIIth Symposium on Vibrations, shocks and noise (VCB 2012) (2012, July)

The present paper addresses the problem of characterising structural nonlinearities in view of system identification. A low-order local modelling strategy is proposed and encapsulated in a recently ... [more ▼]

The present paper addresses the problem of characterising structural nonlinearities in view of system identification. A low-order local modelling strategy is proposed and encapsulated in a recently-introduced frequency-domain nonlinear subspace method for the estimation of model parameters. The complete methodology is first demonstrated using two academic examples, namely a Duffing oscillator and a five-degree-of-freedom system comprising two nonlinearities. The identification of an experimental beam involving nonlinear geometrical behaviour is finally addressed. [less ▲]

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See detailLow-order models of a single-screw expander for organic Rankine cycle applications
Ziviani, Davide; Desideri, Adriano ULiege; Lemort, Vincent ULiege et al

in Low-order models of a single-screw expander for organic Rankine cycle applications D. (2015, September 10)

Screw-type volumetric expanders have been demonstrated to be a suitable technology for organic Rankine cycle (ORC) systems because of higher overall effectiveness and good part-load behaviour over other ... [more ▼]

Screw-type volumetric expanders have been demonstrated to be a suitable technology for organic Rankine cycle (ORC) systems because of higher overall effectiveness and good part-load behaviour over other positive displacement machines. An 11 kWe single-screw expander (SSE) adapted from an air compressor has been tested in an ORC test-rig operating with R245fa as working fluid. A total of 60 steady-steady points have been obtained at four different rotational speeds of the expander in the range between 2000 rpm and 3300 rpm. The maximum electrical power output and overall isentropic effectiveness measured were 7.3 kW and 51.9%, respectively. In this paper, a comparison between two low-order models is proposed in terms of accuracy of the predictions, the robustness of the model and the computational time. The first model is the Pacejka equation-based model and the second is a semi-empirical model derived from a well-known scroll expander model and modified to include the geometric aspects of a single screw expander. The models have been calibrated with the available steady-state measurement points by identifying the proper parameters. 1. [less ▲]

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See detailLow-productive alpha-herpesviridae infection in chronic lichenoid dermatoses
Nikkels, Arjen ULiege; Sadzot-Delvaux, Catherine ULiege; Rentier, Bernard ULiege et al

in Dermatology : International Journal for Clinical & Investigative Dermatology (1998), 196(4), 442-446

BACKGROUND: Herpes simplex virus (HSV) and Varicella-zoster virus (VZV) are responsible for various atypical mucocutaneous manifestations in the immunosuppressed population. One of the causative ... [more ▼]

BACKGROUND: Herpes simplex virus (HSV) and Varicella-zoster virus (VZV) are responsible for various atypical mucocutaneous manifestations in the immunosuppressed population. One of the causative pathomechanisms suggests an altered virus-host cell relationship. OBJECTIVE/METHODS: This report investigates by histology, immunohistochemistry and in situ hybridization the histological and virological features of 6 protracted, indolent HSV infections and 2 prolonged zoster infections. RESULTS: Histopathology revealed a lichenoid dermatitis in all patients. Specific HSV-1, HSV-2 and VZV in situ hybridization proved the viral origin of the cutaneous lesions. Immunohistochemical assessment demonstrated the intracellular presence of the HSV glycoproteins gB, gC and gD in epidermal keratinocytes which did not exhibit cytolysis. Similar findings were obtained for the VZV gE and gB. CONCLUSION: These results suggest that in some instances HSV and VZV infections may present a protracted disease course associated with a lichenoid inflammatory pattern and a non-cytolytic virus-host cell relationship. [less ▲]

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See detailLow-rank optimization for distance matrix completion
Mishra, Bamdev ULiege; Meyer, Gilles ULiege; Sepulchre, Rodolphe ULiege

in Proceedings of the 50th IEEE Conference on Decision and Control (2011, December)

This paper addresses the problem of low-rank distance matrix completion. This problem amounts to recover the missing entries of a distance matrix when the dimension of the data embedding space is possibly ... [more ▼]

This paper addresses the problem of low-rank distance matrix completion. This problem amounts to recover the missing entries of a distance matrix when the dimension of the data embedding space is possibly unknown but small compared to the number of considered data points. The focus is on high-dimensional problems. We recast the considered problem into an optimization problem over the set of low-rank positive semidefinite matrices and propose two efficient algorithms for low-rank distance matrix completion. In addition, we propose a strategy to determine the dimension of the embedding space. The resulting algorithms scale to high-dimensional problems and monotonically converge to a global solution of the problem. Finally, numerical experiments illustrate the good performance of the proposed algorithms on benchmarks. [less ▲]

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See detailLow-rank optimization on the cone of positive semidefinite matrices
Journee, Michel ULiege; Bach, F.; Absil, P.-A. et al

in SIAM Journal on Optimization (2010), 20(5)

Detailed reference viewed: 195 (12 ULiège)
See detailLow-rank optimization with trace norm penalty
Mishra, Bamdev ULiege; Meyer, Gilles ULiege; Bach, Francis et al

E-print/Working paper (2012)

The paper addresses the problem of low-rank trace norm minimization. We propose an algorithm that alternates between fixed-rank optimization and rank-one updates. The fixed-rank optimization is ... [more ▼]

The paper addresses the problem of low-rank trace norm minimization. We propose an algorithm that alternates between fixed-rank optimization and rank-one updates. The fixed-rank optimization is characterized by an efficient factorization that makes the trace norm differentiable in the search space and the computation of duality gap numerically tractable. The search space is nonlinear but is equipped with a particular Riemannian structure that leads to efficient computations. We present a second-order trust-region algorithm with a guaranteed quadratic rate of convergence. Overall, the proposed optimization scheme converges super-linearly to the global solution while still maintaining complexity that is linear in the number of rows of the matrix. To compute a set of solutions efficiently for a grid of regularization parameters we propose a predictor-corrector approach on the quotient manifold that outperforms the naive warm-restart approach. The performance of the proposed algorithm is illustrated on problems of low-rank matrix completion and multivariate linear regression. [less ▲]

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See detailLow-rank plus sparse decomposition for exoplanet detection in direct-imaging ADI sequences. The LLSG algorithm
Gómez González, Carlos ULiege; Absil, Olivier ULiege; Absil, P.-A. et al

in Astronomy and Astrophysics (2016), 589

Context. Data processing constitutes a critical component of high-contrast exoplanet imaging. Its role is almost as important as the choice of a coronagraph or a wavefront control system, and it is ... [more ▼]

Context. Data processing constitutes a critical component of high-contrast exoplanet imaging. Its role is almost as important as the choice of a coronagraph or a wavefront control system, and it is intertwined with the chosen observing strategy. Among the data processing techniques for angular differential imaging (ADI), the most recent is the family of principal component analysis (PCA) based algorithms. It is a widely used statistical tool developed during the first half of the past century. PCA serves, in this case, as a subspace projection technique for constructing a reference point spread function (PSF) that can be subtracted from the science data for boosting the detectability of potential companions present in the data. Unfortunately, when building this reference PSF from the science data itself, PCA comes with certain limitations such as the sensitivity of the lower dimensional orthogonal subspace to non-Gaussian noise. <BR /> Aims: Inspired by recent advances in machine learning algorithms such as robust PCA, we aim to propose a localized subspace projection technique that surpasses current PCA-based post-processing algorithms in terms of the detectability of companions at near real-time speed, a quality that will be useful for future direct imaging surveys. <BR /> Methods: We used randomized low-rank approximation methods recently proposed in the machine learning literature, coupled with entry-wise thresholding to decompose an ADI image sequence locally into low-rank, sparse, and Gaussian noise components (LLSG). This local three-term decomposition separates the starlight and the associated speckle noise from the planetary signal, which mostly remains in the sparse term. We tested the performance of our new algorithm on a long ADI sequence obtained on β Pictoris with VLT/NACO. <BR /> Results: Compared to a standard PCA approach, LLSG decomposition reaches a higher signal-to-noise ratio and has an overall better performance in the receiver operating characteristic space. This three-term decomposition brings a detectability boost compared to the full-frame standard PCA approach, especially in the small inner working angle region where complex speckle noise prevents PCA from discerning true companions from noise. [less ▲]

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See detailLow-temperature chemical vapor deposition of highly-doped n-type epitaxial Si at high growth rate
Nguyen, Ngoc Duy ULiege; Loo, Roger; Caymax, Matty

Conference (2007)

We investigated the growth of in-situ n-type doped epitaxial Si layers with arsenic and phosphorus by means of low-temperature chemical vapor deposition using trisilane as Si-precursor. Indeed, in order ... [more ▼]

We investigated the growth of in-situ n-type doped epitaxial Si layers with arsenic and phosphorus by means of low-temperature chemical vapor deposition using trisilane as Si-precursor. Indeed, in order to prevent the alteration of the characteristics of the devices which are already present on the wafer, an epitaxy process at low temperature is highly desired for applications such as BiCMOS. In this work, the varying parameters are the deposition temperature, the Si-precursor mass flow and the dopant gas flow. As a result, a process for the deposition of heavily doped epilayers was demonstrated at 600 °C with high deposition rate, which is important for maintaining high throughput and low process cost. We showed that using trisilane as a Si-precursor resulted in a much more linear n-type doping behavior than using dichlorosilane. Therefore it allowed an easier process control and a wider dynamic doping range. Our process is an interesting route for the epitaxy of a low-resistance emitter layer for bipolar transistor application. [less ▲]

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See detailLow-temperature epitaxy of highly-doped n-type Si at high growth rate by chemical vapor deposition for bipolar transistor application
Nguyen, Ngoc Duy ULiege; Loo, Roger; Caymax, Matty

in Applied Surface Science (2008), 264

We investigated the growth of in-situ n-type doped epitaxial Si layers with arsenic and phosphorus by means of low-temperature chemical vapor deposition using trisilane as Si-precursor. Indeed, in order ... [more ▼]

We investigated the growth of in-situ n-type doped epitaxial Si layers with arsenic and phosphorus by means of low-temperature chemical vapor deposition using trisilane as Si-precursor. Indeed, in order to prevent the alteration of the characteristics of the devices which are already present on the wafer, an epitaxy process at low temperature is highly desired for applications such as BiCMOS. In this work, the varying parameters are the deposition temperature, the Si-precursor mass flow and the dopant gas flow. As a result, a process for the deposition of heavily doped epilayers was demonstrated at 600 °C with high deposition rate, which is important for maintaining high throughput and low process cost. We showed that using trisilane as a Si-precursor resulted in a much more linear n-type doping behavior than using dichlorosilane. Therefore it allowed an easier process control and a wider dynamic doping range. Our process is an interesting route for the epitaxy of a low-resistance emitter layer for bipolar transistor application. [less ▲]

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See detailLow-viscosity allophanates containing actinically curable groups
Detrembleur, Christophe ULiege; Weikard, Jan; Greszta-Franz, Dorota et al

Patent (2011)

A process for preparing binders containing allophanate groups which contain, at the oxygen atom of the allophanate group that is bonded via two single bonds, organic radicals with activated groups capable ... [more ▼]

A process for preparing binders containing allophanate groups which contain, at the oxygen atom of the allophanate group that is bonded via two single bonds, organic radicals with activated groups capable of participating in a polymerization reaction with ethylenically unsaturated compounds on exposure to actinic radiation; the process includes reacting A) one or more compounds containing uretdione groups with B) one or more OH-functional compounds which contain groups capable of participating in a polymerization reaction with ethylenically unsaturated compounds on exposure to actinic radiation, and C) optionally further NCO-reactive compounds, and D) in the presence of one or more compounds containing phenoxide groups, as catalysts.; The binders can be used in preparing coatings, coating materials, coating compositions, adhesives, printing inks, casting resins, dental compounds, sizes, photoresists, stereolithography systems, resins for composite materials and sealants. [less ▲]

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See detailLow-viscosity allophanates containing actinically curable groups
Detrembleur, Christophe ULiege; Weikard, Jan; Greszta-Franz, Dorota et al

Patent (2008)

A process for preparing binders containing allophanate groups which contain, at the oxygen atom of the allophanate group that is bonded via two single bonds, organic radicals with activated groups capable ... [more ▼]

A process for preparing binders containing allophanate groups which contain, at the oxygen atom of the allophanate group that is bonded via two single bonds, organic radicals with activated groups capable of participating in a polymerization reaction with ethylenically unsaturated compounds on exposure to actinic radiation; the process includes reacting A) one or more compounds containing uretdione groups with B) one or more OH-functional compounds which contain groups capable of participating in a polymerization reaction with ethylenically unsaturated compounds on exposure to actinic radiation, and C) optionally further NCO-reactive compounds, and D) in the presence of one or more compounds containing phenoxide groups, as catalysts.; The binders can be used in preparing coatings, coating materials, coating compositions, adhesives, printing inks, casting resins, dental compounds, sizes, photoresists, stereolithography systems, resins for composite materials and sealants. [less ▲]

Detailed reference viewed: 28 (4 ULiège)
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See detailLow-viscosity allophanates having actinically hardenable groups
Detrembleur, Christophe ULiege

Patent (2007)

Die vorliegende Erfindung betrifft niedrigviskose Umsetzungsprodukte von Polyisocyanaten, die aktivierte unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter ... [more ▼]

Die vorliegende Erfindung betrifft niedrigviskose Umsetzungsprodukte von Polyisocyanaten, die aktivierte unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter Polymerisation reagierende Gruppen enthalten, ein Verfahren zu ihrer Herstellung sowie deren Verwendung in Beschichtungsmitteln. [less ▲]

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See detailLow-viscosity allophanates having actinically hardenable groups
Detrembleur, Christophe ULiege; Weikard, Jan; Richter, Frank et al

Patent (2009)

Die vorliegende Erfindung betrifft niedrigviskose Umsetzungsprodukte von Polyisocyanaten, die aktivierte unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter ... [more ▼]

Die vorliegende Erfindung betrifft niedrigviskose Umsetzungsprodukte von Polyisocyanaten, die aktivierte unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter Polymerisation reagierende Gruppen enthalten, ein Verfahren zu ihrer Herstellung sowie deren Verwendung in Beschichtungsmitteln. [less ▲]

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See detailLow-viscosity allophanates having actinically hardenable groups
Weikard, Jan; Detrembleur, Christophe ULiege; Grestza-Franz, Dorota et al

Patent (2006)

A radiation-curing binder containing allophanate groups is prepared by reacting at =130[deg]C compound(s) containing uretdione groups with OH-functional compounds containing groups reacting with ... [more ▼]

A radiation-curing binder containing allophanate groups is prepared by reacting at =130[deg]C compound(s) containing uretdione groups with OH-functional compounds containing groups reacting with polymerization with ethylenically unsaturated compounds on exposure to actinic radiation, optionally other NCO-reactive compounds, in the presence of a catalyst comprising at least one zinc compound to form allophanate groups by opening the uretdione ring. Independent claims are also included for: (A) a coating composition comprising the radiation-curing binder(s) containing allophanate groups, optionally polyisocyanate(s) containing free or blocked isocyanate groups, which are free from groups which react, with polymerization, with ethylenically unsaturated compounds on exposure to actinic radiation, optionally other compounds containing groups which react, with polymerization, with ethylenically unsaturated compounds on exposure to actinic radiation, and optionally contain free or blocked NCO groups, optionally one or more isocyanate-reactive compounds, initiator(s), and optionally solvents; and (B) a substrate coated with a coating obtained from the radiation-curing binder containing allophanate groups. [less ▲]

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See detailLower Carboniferous shallow marine sequences from the Central Alborz Basin, Iran (north-eastern margin of Gondwana): sedimentology, biostratigraphy and rock– magnetic studies
Sardar Abadi, Mehrdad ULiege

Doctoral thesis (2016)

The Lower Carboniferous Mobarak Formation records the development of a carbonate platform on the southern Paleo-Tethyan passive margin. This pervasive carbonate factory was deposited following the opening ... [more ▼]

The Lower Carboniferous Mobarak Formation records the development of a carbonate platform on the southern Paleo-Tethyan passive margin. This pervasive carbonate factory was deposited following the opening of the Paleo-Tethys Ocean into the Alborz Basin along the northern margin of Gondwana. The depositional facies range from the most proximal to the most distal and include coastal environments, inner ramp peritidal facies, peloidal to crinoidal shoals, storm to fair-weather influenced mid-ramps, proximal to distal shell beds and low energy outer ramps. Storms clearly played a dominant role in the distribution of skeletal and non-skeletal shoals on the carbonate ramp. Sedimentological analyses complemented with foraminiferal biostratigraphy reveal four events which are interpreted to represent the principal factors controlling carbonate platform evolution in the Alborz Basin during the Lower Carboniferous: 1) A transgression linked to global temperature rise in the Early Tournaisian (Middle Hastarain) resulted in the formation of thick-bedded argillaceous limestones. 2) the Hastarian–Ivorian boundary glaciation phase, 3) Upper Ivorian–Lower Viséan? tectonic block faulting. 4) the Viséan- Serpukhovian glaciation phase. The three foraminiferal assemblages encountered in the Tournaisian interval of the Mobarak Formation are restricted to specific periods within the Ivorian. The occurrence of specific foraminiferal taxa in Alborz is tightly governed by transgressions and migration of North Paleo–Tethyan biotic elements as response to the thermal period. We also combined proxies for ambient paleothermometry in addition to the indications for arid conditions and arid conditions and the presence of foraminiferal taxa with a North Paleo-Tethyan affinity in the Lower Carboniferous Mobarak Formation to suggest a paleo-position for the Alborz Basin at lower latitudes than approximately 45  –50  southern paleolatitude reported thus far. Magnetic susceptibility ( in ) was measured and compared with facies from the same sample. There is a clear link between  in and facies, and the average  in values are higher for distal facies than for proximal ones. The  in profile of Lower Carboniferous carbonate sequence reflects stratigraphic variations in response to relative sea level changes and detrital input. In the context of the sequence stratigraphic framework, the average  in values for lowstand and transgressive system tracts deposits are higher than for the highstand system tracts deposits. The clear link between  in and facies points to at least partly preserved primary  in signal, related to detrital inputs. In respect to the hysteresis measurements the in signal is mainly carried by low coercivity ferromagnetic minerals such as magnetite, with a mixture of relatively coarse grains (detrital fraction) and ultra-fine grains (probably formed during diagenesis). [less ▲]

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See detailLower airway dysfunction in athletic horses
Votion, Dominique ULiege; Art, Tatiana ULiege; Lekeux, Pierre ULiege

in In Proceedings: Journées Vétérinaires Suisses (1996, September)

During the last decade, research in exercising horses provided growing evidence that the respiratory system may be a limiting factor for maximal performance, even in healthy animals. Therefore, any ... [more ▼]

During the last decade, research in exercising horses provided growing evidence that the respiratory system may be a limiting factor for maximal performance, even in healthy animals. Therefore, any pulmonary dysfunction, even subclinical or moderate, may significantly impair the aerobic metabolism and consequently performance of exercising horses. This paper briefly presents the main respiratory troubles of lower airway as well as the main pulmonary function tests used to diagnose these diseases. [less ▲]

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See detailLower airway function: response to exercise and training
Art, Tatiana ULiege; Bayly, Warwick

in Hinchcliff, Kenneth W.; Kaneps, Andris J.; Geor, Raymont J. (Eds.) Equine Sports Medicine and Surgery. Basic and clinical Sciences of the Equine Athlete. 2d Edition (2014)

Detailed reference viewed: 24 (3 ULiège)