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Different metals and metal complexes have been used as catalysts in many industries such as commodity petrochemicals, fine and specialty chemicals, polymers, environmental services, agrochemicals and pharmaceuticals. Although these catalysts allow for increased reaction rates and selectivity, they can also be toxic, expensive and of limited supply (cf. Pt group metals). This has led researchers to the intensive study of first row metal catalysts, with nickel standing out as the most widely studied to date. As found for other first row metal catalysts, nickel’s easy access to oxidation states 0-3 allows for a number of different one- and two-electron mechanisms and novel transformations. In Chapter 2 we use a phosphine-free, tridentate N,N,N ligand to generate an active catalyst for the C-N cross-coupling reaction of aryl halides with amines. The catalyst demonstrated excellent turnover numbers (up to 484) for the amination reactions that are proposed to proceed through a Ni(I)-Ni(III) cycle. In Chapter 3 we investigate the Ni coordination chemistry of a biomimetic SNS thiolate ligand. Protonation of the Ni bis(thiolate) complex, Ni(-SNS)2, removes one SNS ligand, affording crystals of a thiolate-bridged dimer dication, {[Ni(--SNS)]2}2+ that exhibits unique anionic tridentate ligand dynamics. Dissolving these crystals, even in weakly-coordinating solvents such as dichloromethane, gives a mixture of ‘naked’ Ni2+ and paramagnetic, trinuclear {[Ni(--SNS)2]2Ni}2+. Although this equilibrium lies far to the right (no diamagnetic dication visible in NMR), addition of ancillary ligands proceeds smoothly to provide several mono- and dinuclear Ni thiolate products, [Ni-SNS)L]n – potential bifunctional catalysts for further studies. In Chapter 4 we demonstrate using chemical and electrochemical techniques that one-electron reduction of Ni(-SNS)2 triggers quantitative imine C-C bond coupling, forming [Ni(S2N2)]- with a redox-active ligand. Spectroelectrochemical studies indicated reversible oxidation and reduction steps give three stable redox states, ([Ni(S2N2)]0/-/2-), that were characterized by NMR, EPR and UV-Vis spectroscopy, X-ray diffraction and computational chemistry. While the Ni(0) dianion (and not the Ni(I) anion) reacted reversibly with phenol and carbon dioxide, results from Chapter 5 showed that reactions with strong electron-acceptor fluoroalkenes proceeded more cleanly with the Ni(I) anion. The latter reactions afforded a mixture of fluoroalkenyl and fluoroalkyl products resulting from C-F bond activation and electron transfer/H atom abstraction, respectively. In Chapter 6 we discuss our results in the context of the current state of the art and suggest some avenues for future development.

Includes bibliographical references. / The crystal structures of trans-9, 10-dihydroxy-9, 10-diphenyl-9, 10- dihydroanthracene with various guest molecules have been determined by X-ray diffraction. The guests were 2-butanone, 4-vinylpyridine, 4-methylpyridine and 2-methylpyridine. The host to guest ratios were determined by microanalysis and density measurements. The change of the overall host lattice structure upon guest release was studied by X-ray powder diffraction. The thermal characteristics of the compounds were studied using thermogravimetric analysis and differential scanning calorimetry. Guest desorption from three of the four compounds occurred in a single step whereupon the host framework collapsed back to the guest-free structure. The compound containing 4-methylpyridine, released the guest molecules in a two-step process. Evidence of a new host phase was identified from the XRD pattern of this intermediate phase. On further guest release, the intermediate phase converted to the guest-free host structure. In an attempt to reconcile thermodynamics with structure, the correlation between hydrogen bond length and guest desorption enthalpy was investigated.

This experiment tested hypotheses linking the right cerebral regulation of hostility and cardiovascular reactivity. First, replication of previous research supporting heightened cardiovascular reactivity (mean arterial pressure, systolic blood pressure, diastolic blood pressure, and heart rate) among high-hostile participants was attempted. Second, dynamic variations in functional cerebral asymmetry in response to pain (cold pressor stressor) and affective verbal learning (positive and negative valenced word lists) were measured. High- and low-hostile participants (n = 64) were identified using the Cook Medley Hostility Scale. Participants completed either the cold-pressor stressor condition or the no-stress control condition as well as the negative and the positive affective verbal learning test. Cardiovascular measures (MAP, SBP, DBP, and HR) before and after the stress or no-stress condition and before and after the negative and the positive affective learning tasks were recorded. The results demonstrated that high-hostiles had difficulty processing emotional stimuli. High-hostiles were reliably impaired in emotional word learning. Further, results suggested that negative affective learning produced proactive interference for the learning or recall of subsequently presented information. Positive affective learning produced diametrically opposite effects with retroactive interference for the recall of previously presented information. Also, high-hostiles' cardiovascular reactivity to a physical stressor was independent of the valence of the learning task. In contrast, low-hostiles' cardiovascular reactivity was valence dependent with activation to both the positive list concurrent with stress and to the negative list concurrent with no stress. Finally, the results indicated that the effect of the affective learning lists, on the heart, is stress dependent. Neuropsychological theories of ANS regulation and emotion are discussed in relation to the primary findings and a new model of lateralized regulation is proposed. / Ph. D.

Les retenues hydroélectriques, au même titre que les voies navigables et les ports maritimes, peuvent être soumises à une accumulation de particules solides. Si la majorité des sédiments est gérée au sein même du cours d'eau par transfert dans le lit aval, des raisons techniques ou environnementales pourraient impliquer à l'avenir une gestion à terre des déblais. Quoique considérées comme des déchets par la réglementation, les matières issues de dragage apparaissent comme une ressource noble et renouvelable. Dans une approche d'économie circulaire, certains secteurs industriels semblent en mesure d'utiliser les sédiments fins de barrage comme des matières premières alternatives, dont l'industrie des liants hydrauliques. Deux modalités de valorisation sont considérées dans cette thèse avec, d'une part, une utilisation comme matière première du cru en vue de la fabrication de clinker et, d'autre part, un emploi comme substitut pouzzolanique au clinker en ciments composés.Par l'étude de 8 sédiments prélevés sur l'ensemble du territoire français, la démarche doit aboutir à dégager des typologies de sédiments fins. Ces matériaux sont caractérisés de façon détaillée sur les aspects physico-chimiques et minéralogiques. Ces caractérisations préalables constituent une approche obligatoire pour, ensuite, tester les deux voies de valorisation matière et vérifier l'adéquation des matériaux issus de dragage.L'emploi de sédiments dans le cru, en substitution aux ressources argileuses traditionnellement utilisées, est expérimenté en laboratoire. Des clinkers maximisant le taux d'incorporation de sédiments fins, entre 25 et 35 % selon le sédiment, sont synthétisés. Les clinkers ainsi produits présentent des particularités microstructurales qu'il faut parfois atténuer par une complémentation en argile de carrière. En somme, il est montré que, quel que soit le sédiment, une valorisation dans le cru semble envisageable tout en anticipant les propriétés du clinker in fine. En démonstration, un ciment CEM I de classe 52,5 N est fabriqué avec un taux d'incorporation de sédiment de 11,4 %.Sur le plan du développement de la réactivité pouzzolanique, un suivi de l'évolution des propriétés physiques et minéralogiques des sédiments avec la température est effectué. En parallèle de ces caractérisations, une évaluation de la réactivité pouzzolanique est conduite avec des essais chimiques et physiques par substitution partielle de ciment Portland par des sédiments calcinés. Cela conduit à déterminer, s'il y a lieu, un optimum de calcination. Les teneurs en kaolinite, de l'ordre de 10 % de certains échantillons étudiés permettent le développement d'une activité pouzzolanique qui peut être modérée à élevée (comparable à une cendre volante). Néanmoins, pour l'ensemble des sédiments riches en calcite et dont le cortège argileux ne présente que des argiles de type illite et chlorite, l'activation est faible ou nulle. / Hydroelectric dams, as well as waterways and marine harbours, can be subject to solid particles accumulation. Although sediment is mainly managed within the watercourse by a transfer into the downstream river bed, technical or environmental reasons might imply an on-land management in the future. Albeit sediments should be considered as waste according to regulations, dredged materials appear as valuable and renewable resources. In a circular economy approach, some industrial sectors could beneficially reuse fine-grained dam sediment as alternative raw materials, including hydraulic binders industry. Then, two ways of reusing are considered in this PhD thesis with on one hand, a valorization as raw material in the clinker meal and, on the other hand, as pozzolanic substitute to clinker in blended cements.Studying 8 different sediments that were sampled on the French territory, the approach aims to encompass various contexts and define some typologies. The materials are characterized in detail on physico-chemical and mineralogical aspects. These preliminary characterisations are necessary in order to test both the beneficial reuse opportunities and check the suitability of dredged sediments.The beneficial reuse of sediment in the clinker raw meal as replacement of traditional clay resources is experimented at the lab scale. Clinkers that maximize the fine-grained sediment content, between 25 and 35 % according to the sediment, are synthetized. These clinkers exhibit some special microstructural features that can be corrected by a clay addition as a third compound. Thus, it is shown that any sediment can be reused in the raw meal and that clinker characteristics can be anticipated and adjusted. As a demonstration, a CEM I 52.5 N cement was obtained incorporating 11.4 % of sediment in the raw meal.Concerning pozzolanic reactivity development, physical and mineralogical sediment characteristics are followed according to the calcination temperature. In parallel, pozzolanic reactivity is assessed with both chemical and physical tests, with a partial substitution of Portland cement by calcined sediments in cement pastes, in order to determine an optimum calcination temperature. Kaolinite contents around 10 % for some of the studied samples lead to a moderate to high pozzolanic reactivity, that can be comparable to fly ash. However, for all the sediments that contain calcite and only illite and chlorite clays, activation is low or null.

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Gestational diabetes mellitus impacts between 3-10% of pregnancies, and increases the risk of pregnancy complications and lifelong health effects for mother and child (Bellamy, Casas, Hingorani, & Williams, 2009; Ross, 2006; Ryser Rüetschi et al., 2016). About half of cases occur without an evident risk factor (American College of Obstetricians and Gynecologists (ACOG), 1994; Dode & Santos, 2009). The present study was designed to examine possible psychophysiological connections linking psychological stress and stress reactivity, the magnitude of an individual’s response to stress, to blood sugar metabolization during mid-pregnancy between 24-28 weeks gestation. Participants were recruited from Sanford Health in Fargo, where patients underwent routine Oral Glucose Tolerance Testing (OGTT) a diagnostic assessment in which higher results indicate less blood sugar metabolization. They also completed a Virtual Trier Social Stress Task while psychological and physiological markers of stress reactivity were assessed. Additionally, maternal stress and stress reactivity were assessed using psychosocial questionnaires. There was support for proposed psychophysiological connections, including models in which positive associations between OGTT and maternal stress and anxiety were moderated by psychological stress reactivity. Results suggest that both the presence of stress and a women’s responses to that stress are influential over blood glucose metabolization during pregnancy. Continuing research in this area may have implications for improving outcomes of women at higher risk of GDM and other adverse pregnancy and perinatal outcomes.

Existing evidence has linked individual differences in emotion reaction intensity to both enhanced and decreased psychological well-being. We propose that this contradiction is related to methodological shortcomings in some existing research. We present a novel emotion reactivity task capable of addressing these methodological shortcomings by continuously measuring the subjective intensity of individual emotion episodes with high temporal resolution. Four studies were conducted (total n = 499). In Studies 1, 2, and 4, participants continuously reported their emotions while viewing objectively pleasant or unpleasant images. Thousands of reaction intensities were coded using algorithms developed for this purpose. We expected that people showing more intense emotion reactions, regardless of valence, would report greater subjective well-being in the lab and in daily life. One reason that such situationally-congruent reactions might be beneficial is that that they enable more flexible situationally-appropriate behavior. In Study 3, participants were asked to rate their emotional responses to pleasant and unpleasant images. Following this, people choose a location for their Self avatar within a computerized environment that included one image of each valence. We expected that the tendency to report intense emotion responses to these images would predict both adaptive location choice and subjective well-being. Results confirmed most major hypotheses: more intense reactions to both positive and negative stimuli were predictive of greater subjective well-being in the lab and in daily life, and analogous reactivity patterns were associated with more flexible, adaptive avatar placement. The results suggest that a key feature of maladaptive emotion generation systems (and lower well-being) may not be overly intense reactions as has been suggested, but a failure to flexibly adapt emotion output to match changing circumstances.

The use of Virtual Reality (VR) and Imagery have been utilized in psychological practices and treatment. VR has recently been the focus of research with treatments for post traumatic stress disorder, substance abuse, and phobias, among other social and behavioral issues. VR allows the researcher to create realistic controlled environments in which they are able to manipulate the experiment. Imagery permits the individual to imagine and recall scenarios from their past in order to create a more personal environment. This experiment aimed to expand upon VR practices and treatment in regards to alcohol research. In this experiment, 70 participants, 39 females and 31 males, were exposed to two VR alcohol and two Imagery alcohol cue environments. Subject craving and psychophysiological measures were taken across all four scenes and all baselines. Overall, craving measures demonstrated that female nondrinkers developed higher cravings during Imagery. Conversely, male social drinkers demonstrated higher cravings during VR. This study supports the use of VR environments in the study of alcohol cue reactivity.

<p> The optimal placement of shutdown systems in power reactors is investigated, in particular, the placement of mechanical and liquid shutoff rods. Two CANDU reactor cores were used as a basis for evaluation. The optimal shutdown system was defined here to be one which, with the least number of rods, maximizes the reactivity depth of the system with the two most effective rods assumed to be absent. It was found that rows of rods placed parallel to the fuel channels were more effective and four of these rows were required in a simple core. For real cores where positions are limited six or seven rows were needed to obtain a large system worth. (Time analysis was not done to evaluate insertion rate and delay effects on the power transient in the case of an accident.) </p> / Thesis / Master of Engineering (MEngr)