Ce doctorat porte sur la fonctionnalisation de silices colloïdales en vue de la rétention de micropolluants métalliques dans des effluents. Les nanoparticules et microparticules ouvrent des potentialités d’application dans de nombreux secteurs industriels (chimie, environnement, pharmacie...). Ainsi, ces travaux de recherche portent sur la synthèse et la caractérisation de matériaux composites submicroniques : il s’agit de silices colloïdales sur lesquelles sont greffés des silanes ou supportés des polysaccharides. Une des applications de ces travaux de recherche porte sur l’adsorption de métaux de transition sur ces composites en solution aqueuse. Dans le cadre de ce doctorat, les caractéristiques des composites sont définies par leur morphologie de surface, par l’étude des groupements fonctionnels présents, par détermination de leurs surfaces spécifiques ainsi qu’en solution aqueuse par détermination de leurs diamètres hydrodynamiques et de leurs potentiels zéta. Dans un premier temps, la fonctionnalisation de la silice a permis le greffage de groupements carboxyliques et amines dont tes taux de greffage obtenus ont été respectivement de 0,47 µmol/m² et 3,86 µmol/m². En présence de groupements amines, le potentiel  des composites est positif jusqu’ à pH 9 alors qu’il est négatif dès pH 3 pour des silices non fonctionnalisées. Dans un second temps, la silice est supportée par du chitosane dont le degré de désacétylation est de 77%. Conjointement, l’encapsulation de la silice est réalisées par du chitosane sur lequel des fonctions carboxyliques ont été greffées. La morphologie des particules est alors modifiée, leurs diamètres hydrodynamiques sont plus élevés et leurs potentiels  sont positifs jusqu’ à pH basique. La rétention d’ions métalliques (Cu(II) et Ni(II)) par ces composites à différents pH est ensuite étudiée. Pour chacun des cations métalliques, les capacités d’adsorption sont déterminées ainsi que les cinétiques d’adsorption. L’application de plusieurs modèles d’isotherme d’équilibre a été réalisée. Dans le cas de Cu(II), à pH 5, les meilleures capacités d’adsorption sont obtenues pour des silices supportées par du chitosane greffé : la capacité de rétention des ions Cu(II) est de 270 mg/g à pH 5. De même, c’est ce composite qui permet la meilleurs rétention des ions Ni(II) à pH 7 avec une capacité d’adsorption de 263 m/g. Concernant la cinétique, le modèle de réaction de surface du pseudo-second ordre s’applique bien aux résultats expérimentaux. / This study is focused on the preparation of three types of silica-based composites for the capture of Cu(II) and Ni(II) ions. The first strategy consists in coating chitosan on colloidal fumed silica after acidic treatment yielding the composite SiO2+CS. The second strategy can be separated into two routes: the first one involves surface grafting of silica with aminopropyltriethoxysilane to obtaining silica particles covered by amino groups (SiO2(NH2)). The second one involves in surface condensation of triethoxysilylbutyronitrile, followed by acidic hydrolysis of the surface-bound nitrile groups affording silica particles covered by carboxyl groups (SiO2(CO2H)). In the last step, chitosan has been grafted on the surface bound NH2 or -CO2H groups yielding the composites SiO2(NH2)+CS or SiO2(CO2H)+CS. The third strategy involves in the modified CS surface with -CO2H groups, followed by coating onto the non-modified silica nanoparticles to obtain the composite SiO2+CS(CO2H). The novel hybrid materials were characterized by IR spectroscopy, scanning electron microscopy, atomic force microscopy, and zeta potential measurements. Batch experiments were conducted to study the sorption performance of these composites for Cu(II) and Ni(II) removal from aqueous solution at optimum pH at 298 K. The kinetics were evaluated utilizing pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all types of adsorbents. The adsorption isotherms were evaluated utilizing Langmuir, Freundlich, and Temkin models. The best interpretation for equilibrium data was given by Langmuir isotherm model. This study demonstrates that the adsorption capacities for Cu(II) ion is more efficient for the SiO2+CS (256 mg g-1) compared to SiO2(NH2) (75 mg g-1). However, the carboxyl grafted CS-coated silica (SiO2+CS(CO2H) exhibited an excellent adsorption capacity (333 mg g-1). In case of Ni(II), based on Langmuir isotherm the maximum adsorption capacity found to be 182 mg g-1for SiO2+CS, and 210 mg g-1 for SiO2(CO2H) + CS. Using single-metal solutions, these adsorbents were found to have an affinity for metal ions in order as Cu(II) > Ni(II). The adsorption of Cu(II) ion by SiO2+CS was affected by the nature of the respective anion. Application of these composite materials to remove Cu(II) and Ni(II) from aqueous solution was shown to be more efficient than the adsorption capacities of many sorbents probed by other research groups.

This thesis explores German responses to United States diplomatic actions during the period, 1939-1941. The history and events involving Europe prior to World War II are discussed.

An ELF noise band observed by the Alouette II satellite has been studied. A digital power spectrum program was set up in order to investigate in detail the noise band spectra. Primary results from this analysis are that: a) for altitudes 500-3000 Km. and all geomagnetic latitudes, sharp lower cutoffs of the noise band occur within ~30Hz of the calculated gyrofrequency, b) upper cutoffs to the noise band occur frequently near harmonics of the gyrofrequency, and c) the noise appears to be Doppler shifted when the angle between the velocity vector of the satellite and the geomagnetic field is near 90°. The occurrence pattern of the noise band has been investigated using available Rayspan analyzed data for epoch 1966. This analysis indicated a pronounced daytime maximum of occurrence. It is shown that almost all aspects of the noise band may be interpreted in terms of the hypothesis of ambient electrostatic proton cyclotron harmonic waves in the ionosphere, and the concomitant accessibility conditions in the spatially varying geomagnetic field. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Charles Wuorinen’s contributions to contemporary music are significant. He has produced more than 260 compositions in a wide array of genres including pieces for orchestra, opera, ballet, chamber ensemble, and soloists. This document serves as an analysis and performance guide for Charles Wuorinen’s work for solo flute, Flute Variations II. Issues of analysis include serial techniques, time-point nesting, and pitch centricity and provide insight into the compositional style of the composer. As this work exhibits techniques borrowed from traditional shakuhachi performance, this document provides a brief history of the shakuhachi and an overview of the shakuhachi techniques utilized in Flute Variations II. The performance guide provides a pedagogical narrative to aid in the synthesis of conceptual ideas with contemporary techniques.

with George Weigel / Devlin Hall 008

Indiana University-Purdue University Indianapolis (IUPUI)

No description available.

The complex heterogeneity of schizophrenia has proved difficult to replicate in preclinical animal models. Of the many molecular targets implicated with schizophrenia, this thesis focuses on synapsin II - a pre-synaptic protein critical for neurotransmission and synaptogenesis; and parvalbumin - a calcium-binding protein found in interneurons of the dorsolateral prefrontal cortex (DLPFC) and the striatum (STR). Patients with schizophrenia display reduced levels of synapsin II mRNA in the DLPFC, while decreased activation of parvalbumin neurons in the same region has resulted in schizophrenia-like cognitive deficits. Knockdown of synapsin II in the medial prefrontal cortex (mPFC) of neonate and adult rats has previously induced schizophrenia-like alterations. However, there are concerns that must be addressed before novel animal models of schizophrenia can be developed using reductions in synapsin II. This thesis was designed to 1) eliminate maternal separation (MS) between post-natal days (PD) 14-23, which correlates with a neurodevelopmental synapsin II model, as a means of inducing schizophrenia-like behaviours; 2) reassess the use of fully and partially phosphorothioated first-generation antisense oligonucleotides to reduce synapsin II levels, and 3) evaluate parvalbumin expression in the STR following synapsin II knockdown. Results from this study indicate 1) a 36 hour MS regimen during PD 14-23 did not cause behavioural changes bearing resemblance to schizophrenia; 2) oligonucleotide sequences stabilized completely with phosphorothioate bonds were insufficient in reducing synapsin II levels and caused localized necrosis, while partially modified sequences induced a slight knockdown effect without cell death; and 3) levels of striatal parvalbumin expression were decreased in rats receiving the partially, but not fully, modified antisense sequences. The findings strengthen the face validity and safety profile of the synapsin II knockdown model. Novel evidence has also been provided for the role of parvalbumin in the striatum and suggests its influence on cognitive dysfunction in schizophrenia. / Thesis / Master of Science (MSc)

No description available.

Computer networks have become increasingly popular over the last ten years. A simple low cost Mini Apple Network that uses Apple II plus computers and Apple's Parallel Interface Cards, is presented here. The Mini Apple Network is driven by PIC DRIVER, a software program that is able to transmit an Applesoft array variable from one computer to another. Three application programs are presented. A comparison is made of the gain in execution time when one, two, and three computers are used to solve the same problem, namely Laplace's partial differential equation. An increase in gain was obtained when the number of computers was increased from one to three. This gain, however, was not ideal, due to the overheard associated with transmitting the data.