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See detailAn analytical pipeline for MALDI in-source decay mass spectrometry imaging
Zimmerman, Tyler ULg; Debois, Delphine ULg; Mazzucchelli, Gabriel ULg et al

in Analytical Chemistry (2011), 83(15), 6090-6097

In-source decay (ISD) fragmentation as combined with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry allows protein sequencing directly from mass spectra. Acquisition of MALDI-ISD ... [more ▼]

In-source decay (ISD) fragmentation as combined with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry allows protein sequencing directly from mass spectra. Acquisition of MALDI-ISD mass spectra from tissue samples is achieved using an appropriate MALDI matrix, such as 1,5-diaminonaphthalene (DAN). Recent efforts have focused on combining MALDI-ISD with mass spectrometry imaging (MSI) to provide simultaneous sequencing and localization of proteins over a thin tissue surface. Successfully coupling these approaches requires the development of new data analysis tools, but first, investigating the properties of MALDI-ISD as applied to mixtures of protein standards reveals a high sensitivity to the relative protein ionization efficiency. This finding translates to the protein mixtures found in tissues and is used to inform the development of an analytical pipeline for data analysis in MALDI-ISD MS imaging, including software to identify the most pertinent spectra, to sequence protein mixtures, and to generate ion images for comparison with tissue morphology. The ability to simultaneously identify and localize proteins is demonstrated by using the analytical pipeline on three tissue sections from porcine eye lens, resulting in localizations for crystallins and cytochrome c. The variety of protein identifications provided by MALDI-ISD-MSI between tissue sections creates a discovery tool, and the analytical pipeline makes this process more efficient. [less ▲]

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See detailANALYTICAL PREDICTION OF THE BEARING RESISTANCE OF BOLTED CONNECTIONS FOR TUBULAR RACKING STRUCTURES
Armenante, Vittorio; D'Antimo, Marina ULg; Demonceau, Jean-François ULg et al

in THE INTERNATIONAL COLLOQUIUM ON STABILITY AND DUCTILITY OF STEEL STRUCTURES, Timisoara 30 May-01 June 2016 (2016, May)

The aim of this paper is to provide a formulation able to predict the resistance of simple shear connections realized by fastening a plate to a hollow square section by means of long bolts. The research ... [more ▼]

The aim of this paper is to provide a formulation able to predict the resistance of simple shear connections realized by fastening a plate to a hollow square section by means of long bolts. The research is motivated by the fact that the rules currently provided by EC3 for defining the bearing resistance of steel connections are limited to the case of stacks of plates, where every plate composing the connection is always restrained out of plane by the adjoining plate or by the bolt head or nut. This is a condition not verified in case of connections realized with long bolts fastening hollow sections. The work is organized in two sections. First, the results of an experimental campaign are presented and successively, the results of a parametric analysis carried out by means of a Finite Element model calibrated on the experimental data are reported. Afterwards, an analytical approach able to include the local buckling effects arising in these kinds of connections is presented, proposing a coefficient for the reduction of the resistance, to be included in the EC3 formulation. [less ▲]

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See detailAnalytical procedure to derive P-I diagram of a beam under explosion
Hamra, Lotfi ULg; Demonceau, Jean-François ULg; Denoël, Vincent ULg

in Proceeding of the IABSE Workshop - Safety, Robustness and Condition Assessments of Structures (2015, February)

The aim of this paper is to study a beam extracted from a frame and subjected to blast loading. The demand of ductility depends on six dimensionless parameters: two related to the blast loading, two ... [more ▼]

The aim of this paper is to study a beam extracted from a frame and subjected to blast loading. The demand of ductility depends on six dimensionless parameters: two related to the blast loading, two referring to the bending behaviour of the beam and two corresponding to the dynamic behaviour of the rest of the structure. We develop a full analytical procedure that provides the ductility demand as a function of these six dimensionless parameters. [less ▲]

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See detailAnalytical Procedure Validation and the Quality by Design Paradigm
Rozet, Eric ULg; Lebrun, Pierre; Michiels, Jean-François et al

in Journal of Biopharmaceutical Statistics (2015)

Since the adoption of the ICH Q8 document concerning the development of pharmaceutical processes following a Quality by Design (QbD) approach, there have been many discussions on the opportunity for ... [more ▼]

Since the adoption of the ICH Q8 document concerning the development of pharmaceutical processes following a Quality by Design (QbD) approach, there have been many discussions on the opportunity for analytical procedure developments to follow a similar approach. While development and optimization of analytical procedure following QbD principles have been largely discussed and described, the place of analytical procedure validation in this framework has not been clarified. This article aims at showing that analytical procedure validation is fully integrated into the QbD paradigm and is an essential step in developing analytical procedure that are effectively fit for purpose. Adequate statistical methodologies have also their role to play: such as design of experiments, statistical modelling and probabilistic statements. The outcome of analytical procedure validation is also an analytical procedure Design Space and from it, control strategy can be set. [less ▲]

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See detailAnalytical Procedure Validation and the Quality by Design Paradigm
Rozet, Eric ULg; Lebrun, Pierre ULg; Michiels, Jean-François et al

in Journal of Biopharmaceutical Statistics (2015), 25

Since the adoption of the ICH Q8 document concerning the development of pharmaceutical processes following a quality by design (QbD) approach, there have been many discussions on the opportunity for ... [more ▼]

Since the adoption of the ICH Q8 document concerning the development of pharmaceutical processes following a quality by design (QbD) approach, there have been many discussions on the opportunity for analytical procedure developments to follow a similar approach. While development and optimization of analytical procedure following QbD principles have been largely discussed and described, the place of analytical procedure validation in this framework has not been clarified. This article aims at showing that analytical procedure validation is fully integrated into the QbD paradigm and is an essential step in developing analytical procedures that are effectively fit for purpose. Adequate statistical methodologies have also their role to play: such as design of experiments, statistical modelling, and probabilistic statements. The outcome of analytical procedure validation is also an analytical procedure design space, and from it, control strategy can be set. [less ▲]

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See detailAnalytical quantification of the inflammatory cell infiltrate and CD95R expression during treatment of drug-induced toxic epidermal necrolysis.
Paquet, Philippe ULg; Jacob, Eric; Damas, Pierre ULg et al

in Archives of Dermatological Research (2005), 297(6), 266-73

The treatment of drug-induced toxic epidermal necrolysis (TEN) remains unsatisfactory. Intravenous immunoglobulins (IVIg) and intravenous cyclosporin A (CsA) have shown some efficacy in short series of ... [more ▼]

The treatment of drug-induced toxic epidermal necrolysis (TEN) remains unsatisfactory. Intravenous immunoglobulins (IVIg) and intravenous cyclosporin A (CsA) have shown some efficacy in short series of patients. We assessed the effects of IVIg and CsA on TEN lesional and apparently uninvolved skin using standard histology and immunohistochemistry. Cutaneous biopsies were taken from necrotic and clinically uninvolved TEN skin at admission (D1) before any treatment, and after a 5-day treatment (D5). Two IVIg-treated patients (0.75 g/kg/day), two CsA-treated patients (5 mg/kg/day) and two control patients only receiving supportive care were compared. Biopsies were examined by standard histology and immunohistochemistry using antibodies directed to CD68 antigen (macrophages), CD45R0 antigen (activated T lymphocytes), Factor XIIIa (dermal dendrocytes) and the CD95 receptor (apoptosis marker). The different cell densities were evaluated by computerized image analysis. The clinical outcomes with the different treatments were also recorded. There was no obvious difference in the duration of hospitalization in intensive care unit between the three groups but one patient passed away in each of the IVIg- and CsA-groups. At D5, no differences were found between the three groups in the histological and clinical rate of re-epithelialization, and in the evolution of T lymphocyte, macrophage and dendrocyte densities in the epidermis and dermis. However, the expression of the CD95 receptor was similarly and strongly abated at D5 in the epidermis of IVIg- and CsA-treated patients, while it was conversely increased in the two patients under supportive care only. Such a difference was found both in necrotic and uninvolved sites. IVIg and CsA treatments thus appeared to exert no obvious effect on the inflammatory infiltrate, but both abated the expression of the CD95 receptor in the skin of TEN patients. This effect did not seem sufficient to fully reverse the clinical evolution of the disease. It is inferred that IVIg and CsA do not completely abate the TEN process. [less ▲]

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See detailAnalytical search of sensory irritation to shampoos in reactive scalp.
PIERARD, Gérald ULg; Hermanns-Lê, Trinh ULg; Franchimont, Claudine ULg et al

in Labome Materials and Methods (2014), 4

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See detailAnalytical sensitivity analysis using the extended finite element method in shape optimization of bimaterial structures
Noël, Lise ULg; Van Miegroet, Laurent; Duysinx, Pierre ULg

in International Journal for Numerical Methods in Engineering (2016)

The present work investigates the shape optimization of bimaterial structures. The problem is formulated using a level set description of the geometry and the extended finite element method (XFEM) to ... [more ▼]

The present work investigates the shape optimization of bimaterial structures. The problem is formulated using a level set description of the geometry and the extended finite element method (XFEM) to enable an easy treatment of complex geometries. A key issue comes from the sensitivity analysis of the structural responses with respect to the design parameters ruling the boundaries. Even if the approach does not imply any mesh modification, the study shows that shape modifications lead to difficulties when the perturbation of the level sets modifies the set of extended finite elements. To circumvent the problem, an analytical sensitivity analysis of the structural system is developed. Differences between the sensitivity analysis using FEM or XFEM are put in evidence. To conduct the sensitivity analysis, an efficient approach to evaluate the so-called velocity field is developed within the XFEM domain. The proposed approach determines a continuous velocity field in a boundary layer around the zero level set using a local finite element approximation. The analytical sensitivity analysis is validated against the finite differences and a semi- analytical approach. Finally our shape optimization tool for bimaterial structures is illustrated by revisiting the classical problem of the shape of soft and stiff inclusions in plates. [less ▲]

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See detailAnalytical solution of a simple artificial lighting scheme to test any lighting software
Embrechts, Jean-Jacques ULg

in Light and Engineering (1998), 6(4)

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See detailAnalytical solution of a simple artificial lighting scheme to test any lighting software
Embrechts, Jean-Jacques ULg

in Computer Modeling & Simulation in Engineering (1998), 3(3)

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See detailAnalytical Solution to Optimal Relocation of Satellite Formation Flying in Arbitrary Elliptic Orbits
Cho, Hancheol ULg; Park, Sang-Young; Yoo, Sung-Moon et al

in Akella, Maruthi; Gearhart, James; Bishop, Robert (Eds.) et al AAS/AIAA Spaceflight Mechanics Meeting, Sedona 28 January - 1 February 2007 (2007, February)

The current paper presents and examines a general analytical solution to the optimal reconfiguration problem of satellite formation flying in an arbitrary eccentric orbit. The proposed approach does not ... [more ▼]

The current paper presents and examines a general analytical solution to the optimal reconfiguration problem of satellite formation flying in an arbitrary eccentric orbit. The proposed approach does not use any simplifying assumptions regarding the eccentricity of the reference orbit. For the fuel optimal reconfiguration problem, continuous and variable low-thrust accelerations can be represented by the Fourier series and summed into closed-form solutions. Initial and final boundary conditions are used to establish the constraints on the thrust functions. The analytical solution can be implicated by the Fourier coefficients that minimize propellant usage during the maneuver. This analytical solution is very useful for designing a reconfiguration controller for satellite formation flying in a general elliptical orbit. [less ▲]

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See detailAnalytical Solution to Optimal Relocation of Satellite Formation Flying in Arbitrary Elliptic Orbits
Cho, Hancheol ULg; Park, Sang-Young; Yoo, Sung-Moon et al

in Aerospace Science and Technology (2013), 25(1), 161-176

The current paper presents and examines a general analytical solution to the optimal reconfiguration problem of satellite formation flying in an arbitrary elliptic orbit. The proposed approach does not ... [more ▼]

The current paper presents and examines a general analytical solution to the optimal reconfiguration problem of satellite formation flying in an arbitrary elliptic orbit. The proposed approach does not use any simplifying assumptions regarding the eccentricity of the reference orbit. For the fuel optimal reconfiguration problem, continuous and variable low-thrust accelerations can be represented by the Fourier series and summed into closed-form solutions. Initial and final boundary conditions are used to establish the constraints on the thrust functions. The analytical solution can be implicated by the Fourier coefficients that minimize propellant usage during the maneuver. This solution is found that compares favorably with numerical simulations. Also, this analytical solution is very useful for designing a reconfiguration controller for satellite formation flying in a general elliptic orbit. [less ▲]

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See detailAnalytical solutions for J 2-perturbed unbounded equatorial orbits
Martinusi, Vladimir ULg; Gurfil, Pini

in Celestial Mechanics and Dynamical Astronomy (2013), 115

While solutions for bounded orbits about oblate spheroidal planets have been presented before, similar solutions for unbounded motion are scarce. This paper develops solutions for unbounded motion in the ... [more ▼]

While solutions for bounded orbits about oblate spheroidal planets have been presented before, similar solutions for unbounded motion are scarce. This paper develops solutions for unbounded motion in the equatorial plane of an oblate spheroidal planet, while taking into account only the J [SUB]2[/SUB] harmonic in the gravitational potential. Two cases are distinguished: A pseudo-parabolic motion, obtained for zero total specific energy, and a pseudo-hyperbolic motion, characterized by positive total specific energy. The solutions to the equations of motion are expressed using elliptic integrals. The pseudo-parabolic motion unveils a new orbit, termed herein the fish orbit, which has not been observed thus far in the perturbed two-body problem. The pseudo-hyperbolic solutions show that significant differences exist between the Keplerian flyby and the flyby performed under the the J [SUB]2[/SUB] zonal harmonic. Numerical simulations are used to quantify these differences. [less ▲]

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See detailAnalytical solutions for the thick-walled cylinder problem modeled with an isotropic elastic second gradient constitutive equation
Collin, Frédéric ULg; Caillerie, Denis; Chambon, René

in International Journal of Solids and Structures (2009), 46

Numerical modelling of localization phenomena shows that constitutive equations with internal length scale are necessary to properly model the post-localization behaviour. Moreover, these models allow an ... [more ▼]

Numerical modelling of localization phenomena shows that constitutive equations with internal length scale are necessary to properly model the post-localization behaviour. Moreover, these models allow an accurate description of the scale effects observed in some phenomena like micro indentation. This paper proposes some analytical results concerning a boundary value problem in a medium with microstructure. In addition to their own usefulness, such analytical solutions can be used in benchmark exercises for the validation of numerical codes. The paper focuses on the thick-walled cylinder problem, using a general small strain isotropic elastic second gradient model. The most general isotropic elastic model involving seven different constants is used and the expression of the analytical solutions is explicitly given. The influence of the microstructure is controlled by the internal length scale parameter. The classical macrostress is no more in equilibrium with the classical forces at the boundary. Double stresses are indeed also generated by the classical boundary conditions and, as far as the microstructure effects become predominant (i.e. the internal length scale is much larger than the thickness of the cylinder), the macrostresses become negligible. This leads to solutions completely different from classical elastic ones. [less ▲]

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See detailAnalytical strategies for the detection of counterfeit erectile dysfunction drugs
Sacré, Pierre-Yves ULg

Doctoral thesis (2011)

Since the late eighties, when it was first mentioned, the worldwide phenomenon of pharmaceutical counterfeiting is growing. Belgian customs often encounter presumed counterfeited medical products in ... [more ▼]

Since the late eighties, when it was first mentioned, the worldwide phenomenon of pharmaceutical counterfeiting is growing. Belgian customs often encounter presumed counterfeited medical products in Belgian airports and ports because of their central position in Europe and their importance in the transit of goods. Further and deeper analyses are required to assess the counterfeit character of these goods and to provide a scientific basis for the eventual legal procedure. As reference laboratory for the federal agency for medicines and health products (FAMHP), the Scientific Institute of Public Health (IPH) frequently analyses illegal and counterfeit pharmaceutical preparations. The present research project was started with the objective of evaluating several existing methods and developing new analytical methods to detect counterfeit erectile dysfunction drugs. This thesis is focused on the analysis of illegal samples of phosphodiesterase type 5 inhibitors (PDE5-i) containing drugs because these are the most counterfeited pharmaceutical specialities in Belgium. The research was divided into a spectroscopic and a chromatographic part: Infrared based spectroscopies have already demonstrated their ability to detect counterfeit drugs. The first part of the study evaluates the capacity of each technique (mid-infrared (mid-IR), near-infrared (NIR) and Raman spectroscopy) separately and their combinations to discriminate genuine from illegal tablets. Then, the Classification And Regression Trees (CART) algorithm has been used to classify the different samples following the classification system of the Dutch National Institute for Public Health and the Environment (RIVM). The second spectroscopic approach used Raman microspectroscopy mapping to detect counterfeited Viagra®. This technique allows the detection of different compounds according to their Raman spectrum but also the study of the distribution of a selected ingredient among the core of a tablet. The chromatographic part consists of the development and validation of a new Ultra High Pressure Liquid Chromatography method coupled with a UV diode array detector (UHPLC-DAD) and compatible with mass spectrometry (MS) to detect and quantify the three authorised phosphodiesterase type 5 inhibitors (sildenafil, tadalafil and vardenafil) and five of their analogues in illegal pharmaceutical preparations. This method has been validated between +/- 5% acceptance limits using the total error approach and has been compared to the official Viagra® assay method. The ability of HPLC-UV impurity fingerprints to detect illegal samples and to predict whether a new unknown sample is genuine has also been evaluated. The developed analytical methods may be included in a general approach to detect counterfeit drugs containing PDE5-i. This generic approach may also be used to detect other types of counterfeited drugs but should therefore be adapted for each type of medicine. [less ▲]

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See detailAnalytical strategies for the detection of counterfeit erectile dysfunction drugs.
Sacre, Pierre-Yves ULg; Deconinck, Eric; De Beer, Jacques

in Wang, Perry; Wertheimer, Albert (Eds.) Counterfeit Medicines Volume II: Detection, Identification and Analysis (2013)

Among all classes of drugs, the type 5 phosphodiesterase inhibitors (PDE5-i) (sildenafil, vardenafil and tadalafil) are the most counterfeited and copied in industrialized countries. This is why it is ... [more ▼]

Among all classes of drugs, the type 5 phosphodiesterase inhibitors (PDE5-i) (sildenafil, vardenafil and tadalafil) are the most counterfeited and copied in industrialized countries. This is why it is very important for regulatory agencies to have a panel of analytical methods to analyse these drugs and to be able to detect counterfeit or substandard medicines. During this chapter, several analytical techniques will be described and discussed. Among spectroscopic techniques, Raman, NIR, FT-IR and chemical imaging techniques will be envisaged. Their ability to detect counterfeits and predict if a new sample is genuine or not will be presented. Other techniques such as XRay powder diffraction and NMR spectroscopies will be briefly presented. Chromatographic impurity fingerprints will be considered and described for the analysis of suspect samples of Cialis® and Viagra®. Once again, the possibility to predict the authenticity of a new sample by the mean of this technique is envisaged. Finally, a MS-compatible UHPLC-UV method for the analysis of the three authorised PDE5-i and some of their analogues will be shortly described. This technique has been validated using spiked placebo samples in a vegetal matrix representing a suspect sample with a complex matrix. As a conclusion, a generic strategy for the detection and quality evaluation of counterfeit drugs will be presented. [less ▲]

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