A method for the determination of low concentrations (<10PPM) of rare earths in minerals and rocks by neutron activation analysis is presented. A 10 min irradiation of sample and standard required no chemical purification owhile a 20hr, irradiation required an ion exchange purification before actual counting. A Li-drifted germanium detector an 1600 channel gamma spectrometer provided sufficient resolution to allow determination of La, Pr, Sm, Eu, Dy, Ho, Yb and Lu in two apatite samples. The results are generally higher than those obtained by other neutron activation analyses. The specific causes are uncertain and can be resolved best by further study and modification of this neutron activation analysis. / Thesis / Bachelor of Science (BSc)

High frequency stimulation of the perforant pathway triggers a prolonged field potential in the dentate gyrus that far outlasts that obtained with single pulses. The late rising component of this field potential has recently been shown to be mediated by N-methyl-D-aspartate (NMDA). In the present thesis, rats were implanted with stimulating electrodes in the perforant pathway and recording electrodes in the dentate gyrus of the hippocampus. Baseline input/output functions of field potentials (or population EPSPs) were established for each rat. Ketamine, an NMDA receptor antagonist, was then administered to confirm its effects on the late component of the EPSP. The late component was measured by subtracting the pulse-evoked from the train-evoked response. Ketamine was shown to significantly attenuate the late component. Diazepam, a GABA agonist, had no significant effect on the late component. Having established an NMDA component in the field potential allows for the monitoring of the levels of NMDA activation over prolonged periods. Hence, the effect of kindling, an animal model of temporal lobe epilepsy, was also determined. Fully kindled rats--defined as those who had experienced four stage 5 seizures--also had significantly attenuated late components. In contrast to decreased late components, kindled rats displayed increased population spike amplitudes and EPSP slopes. Such a decrease in the late component suggests that the NMDA receptor plays a role in kindling. Subjects were also given ketamine and diazepam following kindling, whereby the effects were proportionately the same as those observed prior to kindling. / Thesis / Master of Science (MS)

A fast pneumatic transfer facility was installed at the Nuclear Engineering Teaching Laboratory (NETL) of the University of Texas at Austin for the purpose of cyclic thermal and epithermal neutron activation analysis. In this work efforts were focused on the evaluation of cyclic epithermal neutron activation analysis (CENAA). Various NIST and CANMET certified materials were analyzed by the system. Experiment results showed 110Ag as one of the isotopes favored by the system. Thus, the system was put into practical application for identifying silver concentration in the Arctic atmospheres in air filters collected in 2009, and traces in metallic ores Comparison of silver concentrations via CENAA with the CANMET certified reference materials gave very good results. / text

Installation of exposed fire sprinklers may cause inconvenience in areas where architectural and interior presentation is significant. In order to overcome this inconvenience, recessed and concealed sprinklers were created and are applied widely. Response Time Index (RTI) and C-factor are the thermal sensitivity (intrinsic parameters) used to characterise a sprinkler. They are also used as input parameters in computer fire models to simulate sprinkler response time. However, the RTI and C-factor are not published by the manufactures. Therefore the RTI and C-factor of the recessed and concealed sprinklers have been analysed and determined in this research. In order to obtain the RTI of the recessed and concealed sprinklers, four of the most commonly used sprinkler models (two recessed and two concealed) in New Zealand have been investigated in plunge test experiment by using a wind tunnel in this research. The UC3 wind tunnel used to conduct the plunge test has been fabricated in this research. This work has demonstrated that the UC3 wind tunnel could provide a very stable and uniform temperature profile in the test section. However, the velocity uniformity of the tunnel needs to be improved in the future. The "apparent" RTI for different recessed and concealed sprinkler models (two recessed and two concealed) have been determined in the plunge test experiment. It should be noted that the "final calculated RTI" for each tested recessed and concealed sprinklers has been denoted as "apparent RTI" in this study. BRANZFIRE computer model has been used to model the fire scenarios in the full scale fire tests conducted by Bill and Heskestad (1995). The best input fire object location, the best input sprinkler distance below the ceiling and the input "apparent C-factor" in BRANZFIRE for the flush, recessed, concealed and the recessed sidewall sprinklers have been determined in this research. This work has generally improved the guidance available to fire safety engineers for the RTI and C-factor of the recessed and concealed sprinklers.

The work described in this thesis documents the development of new rhodium(I)-catalysed methodologies within two areas of research. The first examines the use of carbonyls as chelating groups in hydroacylation to produce synthetically valuable ketones and enones. The second area explores new carbon-carbon bond activation methodologies. Chapter 1 presents a literature review of the historical development of rhodium-catalysed hydroacylation, with a focus on chelating groups that can currently be used to suppress decarbonylation. A brief review of methodologies that avoid the requirement for a tether is also included. Chapter 2 describes the development of a novel hydroacylation methodology employing carbonyl-based functional groups as tethers on aldehyde substrates. The chapter begins with the optimisation studies for the hydroacylation of &beta;-formyl amides with terminal and internal alkynes, allenes and terminal alkenes, and subsequently explores the substrate scope for each case. The chapter then outlines the investigations undertaken with 1,4-dicarbonyl and 1,5-dicarbonyl systems, N-formyl amides, &beta;-formyl esters and finally &beta;-formyl ketones. A detailed description of the routes undertaken to synthesise each starting material is also presented. Chapter 3 presents a short review surveying the key milestones in the development of carbon-carbon activation methodologies. The chapter begins with a theoretical comparison to carbon-hydrogen activation and a discussion of the unique challenges that are faced. An overview of the major strategies employed to enact these processes is subsequently presented for both strained and unstrained substrates. Chapter 4 outlines the attempts undertaken to develop a novel carbon-carbon bond activation methodology. The work evaluates sulfur-, nitrogen- and alkene-based chelating groups, known to be successful in hydroacylation, in analogous ketone substrates. Chapter 5 discusses the conclusions from this work and the potential for further work. Chapter 6 presents the experimental procedures and data.

Le radiomarquage de molécules d’intérêt avec des isotopes radioactifs est d'un grand intérêt pour la communauté scientifique, car il influe fortement sur le processus de découverte dans les sciences de la vie et en médecine nucléaire. Les molécules radiomarquées ont été largement utilisées pour évaluer les réactions biochimiques, pour mesurer la distribution in vivo d'une substance ou pour réaliser des tests RIA (RadioImmunoAssay). En médecine nucléaire, des radiopharmaceutiques pour la thérapie par ra-dio-isotopes (RIT) et des radiotraceurs pour des expériences d'imagerie telles que la TEP (tomographie par émission de positons), la tomographie par émission monophotonique (TEMP) ou la scintigraphie ont été décrites. Plusieurs isotopes de l'iode peuvent être utilisés à la fois pour le diagnostic et le traite-ment : 123I pour l'imagerie TEMP, 124I pour la TEP, 125I pour l'analyse biologique et 131I pour la radio-thérapie et la scintigraphie.Les méthodes classiques de radio-iodation reposent sur l'utilisation d'un précurseur pré-fonctionna-lisé, qui doit être synthétisé, isolé et purifié avant d'être introduit à l'étape de radio-iodation. La méthode par radioiododéstannylation est la méthode la plus populaire, bien que les précurseurs stannylés soient connus pour leur synthèse difficile et leur toxicité. Le développement de nouvelles méthodes de radio-iodation représente donc un grand intérêt dans le domaine de la radiochimie.Sur la base de travaux antérieurs, notre groupe a mis au point une méthode de radio-iodation de N-acylsulfonamides au moyen d’une radio-iodation C-H médiée par le palladium à température ambiante. Cette stratégie originale permet le radiomarquage de molécules d’intérêt dans des conditions très douces sans utiliser de précurseurs chimiques.Sur la base de la littérature, notre groupe développe actuellement une nouvelle méthode de radio-iodation de dérivés d’arylsilanes par radioiododésilylation dans des conditions douces. Cette méthodo-logie générale permet pour le moment le radiomarquage de dérivés d'arylsilanes activés en conditions douces. / Labeling of (bio)molecules with radioactive isotopes is of high interest to for the scientific commu-nity, as it strongly impacts the discovery process in life science and nuclear medicine. Radiolabeled molecules have been extensively used to assess biochemical reactions, to measure in vivo distribution of a substance or to preform RIA (RadioImmunoAssay). In nuclear medicine, radio-therapeutics for RIT (RadioIsotope Therapy) and radio-tracers for molecular imaging experiments such as PET (Positron Emission Tomography), SPECT (Single Photon Emission Computed Tomography) or scintigraphy have been described. Several useful isotopes of iodine can be used for both diagnosis and therapy: 123I for SPECT imaging, 124I for PET imaging, 125I for biological assays and 131I for radio-therapy and scintig-raphy.Classical methods of radioiodination methods use a prefunctionalized precursor, which must be syn-thesized, isolated and purified before being introduced to the radio-iodination step. The radioiodode-stannylation method is the most popular method, although stannylated precursors are known for their difficult synthesis and their toxicity. The development of new methods of radioiodination is therefore of great interest in the field of radiochemistry.Based on a previous work, our group has developed a method to radio-iodinate N-acylsulfonamides through a room temperature palladium mediated C-H radio-iodination. This original strategy allows radiolabeling of biomolecules in very mild conditions without the use of chemical precursors.Based on literature, our group is now developping a new method to radio-iodinate arylsilyl derivates through radioiododesilylation in mild conditions. This general methodology allows for the moment the radiolabeling of activated arylsilyl derivates in mild conditions.

Le facteur de transcription NF-KB joue un rôle essentiel dans le développement, l’homéostasie, la survie du système immunitaire, mais également dans la propagation de certains lymphomes. L’activation optimale de NF-ΚB en réponse à l’engagement de nombreux immunorécepteurs repose sur la mise en place de larges signalosomes dans lesquels des adaptateurs spécifiques sont recrutés et poly-Ubiquitinylés de façon non-Dégradative. En réponse à des cytokines pro-Inflammatoires ou à l’activation des récepteurs antigéniques, ces adaptateurs ubiquitinylés s’accumulent sur la face cytoplasmique du réticulum endoplasmique (RE) via la protéine du RE metadherine (MTDH) qui assure la propagation du signal NF-KB. Toutefois, la nature des E3 ligases en charge de relayer NF-KB au niveau des organites intracellulaires reste méconnue. C’est pourquoi j’ai réalisé le crible par bioluminescence d’une librairie de siRNA dirigée contre les 46 E3 ubiquitine ligases humaines pourvues d’un domaine transmembranaire qui les ancrent au niveau de différents compartiments cellulaires afin d’étudier leur impact sur l’activation de NF-KB en réponse à une stimulation antigénique dans un modèle de lymphocytes T immortalisés Jurkat. Nous avons identifié la protéine du RE TRIM13 comme un régulateur positif de la signalisation NF-ΚB. Nos données suggèrent un modèle dans lequel TRIM13 régule l’activation de NF-KB en modulant indépendamment l’activation de deux membres clés de la famille NF-KB au cours de l’activation lymphocytaire, RelA (p65) et c-Rel.Lors de cette thèse, j’ai également participé au crible d’une librairie de siRNA ciblant les 96 déubiquitinases (DUBs) codées par le génome humain afin d’identifier celles en charge de ramener les cellules vers leur état basal. Ceci a permis la caractérisation de la protéase spécifique de l’ubiquitine USP34 (Ubiquitin specific protease 34). La réduction des niveaux endogènes de USP34 potentialise l’activation de NF-KB en réponse à l’engagement du récepteur antigénique T ou du récepteur au TNFa et la liaison de NF-KB à l’ADN est accrue. Collectivement, ces résultats suggèrent que USP34 est un nouvel acteur impliqué dans la régulation négative de NF-KB.Ces résultats illustrent l’importance des processus d’ubiquitination réversibles dans la régulation de la signalisation NF-ΚB et introduisent les cribles génétiques comme un outil efficace pour l’identification de régulateurs de processus biologiques divers. / The transcription factor NF-KappaB plays a critical role in the development, homeostasis, the survival of the immune system, but also in the propagation of certain lymphomas. The optimal activation of NF-KappaB in response to the engagement of many immunoreceptors rely on the implementation of large signalosomes where specific adaptors are recruited and poly-Ubiquitinylated in a non-Degradative manner. In response to proinflammatory cytokines or activation of antigen receptors, these Ubiquitinylated adaptors accumulate on the cytoplasmic leaflet of the endoplasmic reticulum (ER) via the ER protein metadherin (MTDH) providing NF-KappaB signal propagation . However, the nature of the E3 ligases responsible for relaying NF-KappaB in intracellular organelles remains unknown. This is why I made the screen ingby bioluminescence of a library of siRNAs targeting the 46 human ubiquitin E3 ligases provided with a transmembrane domain that anchor them at different cellular compartments to study their impact on the NF-KappaB activation in response to antigenic stimulation in immortalized T lymphocytes Jurkat. We identified the ER-Protein TRIM13 as a positive regulator of NF-KappaB signaling. Our data suggest a model in which TRIM13 regulates the activation of NF-KappaB activation by modulating independently two key members of the NF-KappaB family during lymphocyte activation, RelA (p65) and c-Rel. In this thesis, I also participated in the screening of a library of siRNAs targeting the 98 deubiquitinases (DUBs) encoded by the human genome to identify those in charge of the reset of the system to basal state. This screen allowed the characterization of the ubiquitin-Specific protease USP34 (ubiquitin specific protease 34). The reduction of endogenous levels of USP34 potentiates the activation of NF-KappaB in response to engagement of the antigen receptor or T receptor antagonists and enhances NF-KappaB DNA binding. Collectively, these results suggest that USP34 is a new player involved in the negative regulation of NF-KappaB. These results illustrate the importance of reversible ubiquitination process in the regulation of the NF-KappaB signaling and introduce genetic screens as an effective tool to identify regulators of diverse biological processes.

The present thesis comprises synthesis and stoichiometric model reactions of well-defined NHC-stabilized copper(I) complexes (NHC = N-heterocyclic carbene) in order to understand their basic reactivity in borylation and cross-coupling reactions. This also includes the investigations of the reactivity of the ligands used (NHCs and CaaCs = cyclic alkyl(amino)carbenes) with the substrates, i.e. diboron(4) esters and arylboronates, which are addressed in the second part of the thesis. / Die dargelegte Arbeit gliedert sich in zwei Teile. In einem ersten wird die Synthese sowie stöchiometrische Modell-Reaktionen von definierten NHC-stabilisierten Kupfer(I)-Komplexen (NHC = N-heterocyclisches Carben) untersucht, um Einblick in das grundlegende Reaktionsverhalten in Borylierungs- und Kreuzkupplungsreaktionen zu erlangen. Der zweite Teil adressiert die Reaktivität der eingesetzten Liganden (NHCs und CaaCs = cyclische Alkyl Amino Carbene) gegenüber verwendeten sowie möglichen Substraten (Arylboronsäureester und Diboran(4)-Verbindungen).

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