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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

<p>The combination of collision-activated dissociation, (CAD) and electron capture dissociation, (ECD) yielded a 125% increase in protein identification. The S-score was developed for measuring the information content in MS/MS spectra. This measure made it possible to single out good quality spectra that were not identified by a search engine. Poor quality MS/MS data was filtered out, streamlining the identification process.</p><p>A proteomics grade de novo sequencing approach was developed enabling to almost completely sequence 19% of all MS/MS data with 95% reliability in a typical proteomics experiment.</p><p>A new tool, Modificomb, for identifying all types of modifications in a fast, reliable way was developed. New types of modifications have been discovered and the extent of modifications in gel based proteomics turned out to be greater than expected.</p><p>PhosTShunter was developed for sensitive identification of all phosphorylated peptides in an MS/MS dataset.</p><p>Application of these programs to human milk samples led to identification of a previously unreported and potentially biologically important phosphorylation site.</p><p>Peptide fragmentation has been studied. It was shown emphatically on a dataset of 15.000 MS/MS spectra that CAD and ECD have different cleavage preferences with respect to the amino acid context.</p><p>Hydrogen rearrangement involving z• species has been investigated. Clear trends have been unveiled. This information elucidated the mechanism of hydrogen transfer.</p><p>Partial side-chain losses in ECD have been studied. The potential of these ions for reliably distinguishing Leu/Iso residues was shown. Partial sidechain losses occurring far away from the cleavage site have been detected. </p><p>A strong correlation was found between the propensities of amino acids towards peptide bond cleavage employing CAD and the propensity of amino acids to accept in solution backbone-backbone H-bonds and form stable motifs. This indicated that the same parameter governs formation of secondary structures in solution and directs fragmentation in peptide ions by CAD.</p>

The combination of collision-activated dissociation, (CAD) and electron capture dissociation, (ECD) yielded a 125% increase in protein identification. The S-score was developed for measuring the information content in MS/MS spectra. This measure made it possible to single out good quality spectra that were not identified by a search engine. Poor quality MS/MS data was filtered out, streamlining the identification process. A proteomics grade de novo sequencing approach was developed enabling to almost completely sequence 19% of all MS/MS data with 95% reliability in a typical proteomics experiment. A new tool, Modificomb, for identifying all types of modifications in a fast, reliable way was developed. New types of modifications have been discovered and the extent of modifications in gel based proteomics turned out to be greater than expected. PhosTShunter was developed for sensitive identification of all phosphorylated peptides in an MS/MS dataset. Application of these programs to human milk samples led to identification of a previously unreported and potentially biologically important phosphorylation site. Peptide fragmentation has been studied. It was shown emphatically on a dataset of 15.000 MS/MS spectra that CAD and ECD have different cleavage preferences with respect to the amino acid context. Hydrogen rearrangement involving z• species has been investigated. Clear trends have been unveiled. This information elucidated the mechanism of hydrogen transfer. Partial side-chain losses in ECD have been studied. The potential of these ions for reliably distinguishing Leu/Iso residues was shown. Partial sidechain losses occurring far away from the cleavage site have been detected. A strong correlation was found between the propensities of amino acids towards peptide bond cleavage employing CAD and the propensity of amino acids to accept in solution backbone-backbone H-bonds and form stable motifs. This indicated that the same parameter governs formation of secondary structures in solution and directs fragmentation in peptide ions by CAD.

Reproduction de : Thèse de doctorat : Catalyse de coordination : Toulouse, INPT : 2004. / Titre provenant de l'écran-titre. Bibliogr. 139 réf.

Reproduction de : Thèse de doctorat : Génie des procédés et environnement : Toulouse, INPT : 2004. / Titre provenant de l'écran-titre. Bibliogr. 98 réf.

The use of compliant coatings, in particular polyurea, for improved blast protection of structures has been reported recently in the literature. The goal of this research is to develop a comprehensive understanding of the reasons for improved performance of coated structures through experimentation and correlation with simulation. The different factors influencing the response of an elastomer coated ductile metal subjected to a blast load have been examined and quantified. First, dynamic strain localization in the metal is a precursor to ductile failure; this was characterized for the metal of interest with and without the polymer coating. Experiments with the expanding ring/tube and experiments have demonstrated that for Al 6061-O and Al 3003-H14, the localization strain is unaffected by both deformation rate and the polymer coating; however, two important effects of the coating have been explored. First the additional mass of the coating provides an inertial resistance. Second, the flow resistance of the polymer provides continued dissipation of energy even after the metal has yielded potentially preventing failure in the metal, or at least containing fragments. These effects were examined for two different types of polymers – polyurea, an elastomer and polycarbonate, a thermoplastic shear yielding polymer. It is shown that these two effects can be used to tailor the coating to optimize blast protection of the bilayer system. In order to take advantage of this optimization, the constitutive behavior of the elastomer coating must be determined at strain rates and loading conditions that are experienced in the blast loading; these strain rates are in the range of 1000 to 10,000 per second. This has been accomplished through a hybrid method that combines measurements with numerical simulations to extract the constitutive response of the material. The strain rate dependent behavior of polyurea for rates in the range of 800-8000 per second has been determined by measuring the spatio-temporal evolution of the particle velocity and strain in a thin strip subjected to high speed impact loading that generates uniaxial stress conditions and comparing this with numerical simulations of the one-dimensional problem using the method of characteristics. A similar scheme to track the particle velocity and strain during the axisymmetric deformation of a membrane subjected to high speed loading has also been developed; this requires two projections of the deformation to be obtained in order to facilitate the measurement of axial and kink waves in the membrane. The finite volume method is adapted for simulations of these dynamic uniaxial and axisymmetric problems with a view towards simulating shock waves that are expected to form in some loading conditions. The hybrid method is used once again to characterize the constitutive response. The axisymmetric experiments have demonstrated the inability of the uniaxial models for both polyisoprene rubber and polyurea to completely capture their behavior during a more complex loading, and left a need for further work on characterizing the dynamic constitutive response of these polymers. / text

Drilling and blasting are seen as sub-systems of size reducing operations in mining. To have better design parameters for economical excavation of mineral production and fragmentation, the comminution and fragmentation operations need to be studied and optimized independently, as well as together, to create optimized use of energy and cost-effective operation. When there is a change in drillhole diameter or fragmentation specification, changes in the blast design parameters are required affecting the cost of a drilling and blasting operation. A model was developed to calculate blast design parameters and costs on the basis of the required 80% fragment size needed for crusher operation. The model is based on previously developed fragmentation models, found in the literature. The model examines the effect of drilling diameter on blasting requirements to achieve certain fragmentation targets and calculates blast design parameters and costs for a range of diameters from 75 to 350 mm. To examine the effectiveness of this model, two different 80% passing sizes of fragments have been considered. It was shown that cost optimization occurs at an intermediate diameter, since there are opposing trends of the effect of diameter on powder factor and accessories needed. To achieve a certain fragmentation target, the total cost of drilling and blasting shows a clear trend allowing an optimum selection of diameter. The selected diameter also allows the examination of the suitability of the drill machine under the given geological and operational conditions of the drilling site. / Thesis (Master, Mining Engineering) -- Queen's University, 2009-03-27 07:34:33.787