Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1982 / Includes bibliographical references. / by Lynda Gail Sturgeoff. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Chemistry

Heart rate variability as a measure of cardiovascular health and autonomic activity correlates with psychological resiliency but is not consistently related to trait extraversion, a strong predictor of emotional well-being. This study intends to clarify research findings about trait extraversion and heart rate variability by identifying the context and nature of the relationship between extraversion and physiological responses. As a secondary analysis of data from a study comparing biofeedback and compassionate breathing, extraversion scores were compared with heart rate variability data at three different points including prior to a stressor, during exposure to a stressor, and recovery to a stressor to determine the influence of extraversion on stress reactivity and stress recovery. In our sample population of 80 participants who were mostly young and in good health determined by self-report, the average extraversion score 79.14. Linear regression was used to compare differences at each time point and data was analyzed for significance at p=.05; a post-hoc power analysis revealed β = .81, 1 – β. There were no significant findings between extraversion and heart rate variability at any time point. The results of this study support no relationship between extraversion, health, and stress-resiliency.

This investigation provides a comprehensive experimental dataset and kinetic model for biomass gasification, over a wide temperature range (1150-1350 °Ï¹) in CO2, H2O and the combination of these two reactant gases over the mole fraction ranges of 0 to 0.5 for H2O and 0 to 0.9 for CO2. The data come from a unique experimental facility that tracks continuous mass loss rates for poplar wood, corn stover and switchgrass over the size range of 6-12.5 mm. In addition, the data include char size, shape, surface and internal temperature and discrete measurements of porosity, total surface area, pore size distribution and composition. This investigation also includes several first-ever observations regarding char gasification that probably extend to char reactivity of all types and that are quantified in the model. These include: the effect of ash accumulation on the char surface slowing the apparent reaction rate, changes in particle size, porosity and density as functions of burnout, and reaction kinetics that account for all of these changes. Nonlinear least-squares regression produces optimized power-law model parameters that describe gasification with respect to both CO2 and H2O separately and in combination. A single set of parameters reasonably describes rates for all three chars. Model simulations agree with measured data at all stages of char conversion. This investigation details how ash affects biomass char reactivity, specifically the late-stage burnout. The ash contents ratios in the raw fuels in these experiments are as high as 40:1, providing a clear indication of the ash effect on the char reactivity. The experimental results definitively indicate a decrease in char reaction rate with increasing initial fuel ash content and with increasing char burnout -- most pronounced at high burnout. This investigation postulates that an increase in the fraction of the surface covered by refractory material associated with either higher initial ash contents or increased burnout decreases the surface area available for reaction and thus the observed reaction rate. A quantitative model that includes this effect predicts the observed data at any one condition within the data uncertainty and over a broad range of fuel types, particle sizes, temperatures, and reactant concentrations slightly less accurately than the experimental uncertainty. Surface area, porosity, diameter, and density predictions from standard models do not adequately describe the experimental trends. Total surface area increases slightly with conversion, with most of the increase in the largest pores or channels/vascules not measurable by standard surface area techniques but most of the surface area is in the small pores. Porosity also increases with char conversion except for abrupt changes associated with char and ash collapse at the end of char conversion. Char particle diameters decrease during these kinetically controlled reactions, in part because the reaction is endothermic and therefore proceeds more rapidly at the comparatively warmer char surface. SEM images qualitatively confirm the quantitative measurements and imply that the biomass microstructure does not appreciably change during conversion except for the large pore diameters. Extant char porosity, diameter, surface area, and related models do not predict these trends. This investigation suggests alternative models based on these measurements.

Background: The recent literature has shown that triple antiplatelet therapy with cilostazol in addition to the standard dual antiplatelet therapy with aspirin and clopidogrel may reduce platelet reactivity and improve clinical outcomes following percutaneous coronary intervention. The purpose of this meta-analysis is to compare the efficacy of triple antiplatelet therapy and dual antiplatelet therapy in regard to on-treatment platelet reactivity. Methods: Nine studies (n = 2179) comparing on-treatment platelet reactivity between dual antiplatelet therapy (n = 1193) and triple antiplatelet therapy (n = 986) in patients undergoing percutaneous coronary intervention were included. Primary end points were P2Y12 reaction unit (PRU) and platelet reactivity index (PRI). Secondary end points were platelet aggregation with adenosine diphosphate (ADP) 5 and 20 μmol/L and P2Y12% inhibition. Mean difference (MD) and 95% confidence intervals (CI) were computed and 2-sided α error <.05 was considered as a level of significance. Results: Compared to dual antiplatelet therapy, triple antiplatelet therapy had significantly lower maximum platelet aggregation with ADP 5 μmol/L (MD: -14.4, CI: -21.6 to -7.2, P < .001) and 20 mmol/L (MD: -14.9, CI: -22.9 to -6.8, P < .001), significantly lower PRUs (MD: -45, CI: -59.4 to -30.6, P < .001) and PRI (MD: -26, CI: -36.8 to -15.2, P < .001), and significantly higher P2Y12% inhibition (MD: 18.5, CI: 2.3 to 34.6, P = .025). Conclusion: Addition of cilostazol to conventional dual antiplatelet therapy significantly lowers platelet reactivity and may explain a decrease in thromboembolic events following coronary intervention; however, additional studies evaluating clinical outcomes will be helpful to determine the benefit of triple antiplatelet therapy.

Background: The recent literature has shown that triple antiplatelet therapy with cilostazol in addition to the standard dual antiplatelet therapy with aspirin and clopidogrel may reduce platelet reactivity and improve clinical outcomes following percutaneous coronary intervention. The purpose of this meta-analysis is to compare the efficacy of triple antiplatelet therapy and dual antiplatelet therapy in regard to on-treatment platelet reactivity. Methods: Nine studies (n = 2179) comparing on-treatment platelet reactivity between dual antiplatelet therapy (n = 1193) and triple antiplatelet therapy (n = 986) in patients undergoing percutaneous coronary intervention were included. Primary end points were P2Y12 reaction unit (PRU) and platelet reactivity index (PRI). Secondary end points were platelet aggregation with adenosine diphosphate (ADP) 5 and 20 μmol/L and P2Y12% inhibition. Mean difference (MD) and 95% confidence intervals (CI) were computed and 2-sided α error <.05 was considered as a level of significance. Results: Compared to dual antiplatelet therapy, triple antiplatelet therapy had significantly lower maximum platelet aggregation with ADP 5 μmol/L (MD: -14.4, CI: -21.6 to -7.2, P < .001) and 20 mmol/L (MD: -14.9, CI: -22.9 to -6.8, P < .001), significantly lower PRUs (MD: -45, CI: -59.4 to -30.6, P < .001) and PRI (MD: -26, CI: -36.8 to -15.2, P < .001), and significantly higher P2Y12% inhibition (MD: 18.5, CI: 2.3 to 34.6, P = .025). Conclusion: Addition of cilostazol to conventional dual antiplatelet therapy significantly lowers platelet reactivity and may explain a decrease in thromboembolic events following coronary intervention; however, additional studies evaluating clinical outcomes will be helpful to determine the benefit of triple antiplatelet therapy.

Experts have argued that hoarding disorder occurs in part because hoarding behaviors help individuals avoid distress and feel positive emotions in the moment. For example, when people who hoard choose to save something rather than discard it, they may avoid feelings of anxiety, and when people who hoard acquire something new, they may feel excited. However, no previous studies have examined whether or not these changes actually occur in the moment. These processes could also potentially be altered by how individuals respond to their emotions in the moment. For example, individuals who hoard may have stronger emotional reactions, distinguish less between different emotions, tend to avoid their emotions more, or tend to be inattentive of their experience, which could change how their emotions in the moment affect their behavior. Therefore, this study examined whether or not the anticipated effects of hoarding behaviors on mood occurred, and whether or not there were differences between those with higher and lower hoarding scores on how they respond to their emotions, in a sample of 61 college students. Participants completed two online surveys one week apart, and responded to questions on their mobile phone throughout the week. As expected, the students with higher hoarding scores had stronger emotional reactions to stress, avoided their emotions more often, and were less attentive to their ongoing experience. Both those with higher hoarding scores and lower hoarding scores vi reported that they acquired new items primarily to feel good. However, acquiring, discarding, working with items, and looking for items did not change either group’s mood in the moment. Overall, these findings suggest that people who hoard do have differences in how they respond to their emotions, which could mean that treatments that target these responses may be useful for these people. They also show the importance of understanding why working to put yourself in a good mood through acquiring is problematic for some people and not others, and suggest that there may be a difference between how these behaviors are intended to perform and their actual results.

La nécessité de construire des édifices moléculaires complexes s'accompagne d'un besoin de mise au point d'outils synthétiques nouveaux et toujours plus performants. Dans ce contexte, le développement de systèmes photocommutables constitue un moyen privilégié pour la modulation de la réactivité chimique avec un excellent contrôle spatial et temporel. Les complexes organométalliques incorporant des ligands photochromes constituent des candidats de choix pour de telles applications, combinant la réactivité riche du centre métallique avec les propriétés de photocommutation du ligand. Ces travaux de thèse portent sur l'utilisation d'azobenzènes en tant que ligands pour la formation de complexes photocommutables de type (η6-arène)ruthénium. L'étude du comportement d'azobenzènes diversement substitués a conduit à la synthèse d'une nouvelle famille de complexes porteurs d'un ligand o-sulfonamide azobenzène dont les propriétés de photo-isomérisation ainsi que la réactivité ont été étudiées. La coordination de dérivés phosphorés à ces composés peut être modulée sous irradiation lumineuse, et cette propriété a été exploitée pour le photo-déclenchement de la réaction d'aza-Morita-Baylis-Hillman.Dans une seconde partie de ces travaux, nous avons synthétisé une famille d'azobenzènes cycliques pontés par un acétal présentant un processus nouveaux de photo-isomérisation à trois espèces, qui permet l'interconversion sous irradiation lumineuse entre des diastéréoisomères conformationnels stables avec une bonne sélectivité. Ces nouveaux composés offrent des perspectives prometteuses pour le contrôle conformationnel par la lumière. / The growing need to create sophisticated molecules and building blocks requires the development of increasingly more efficient synthetic tools. In this context, photoswitchable systems appear as an ideal means for controlling chemical reactivity with excellent spatial and temporal resolution. Organometallic complexes incorporating photochromic ligands represent a promising class of compounds for such applications as they combine both the versatile reactivity of the metal center with the photoswitchable properties of the ligand. This work investigates the use of azobenzenes as ligands for the synthesis of photoswitchable (η6-arene)ruthenium complexes. The study of the behavior of azobenzenes diversely substituted led to the synthesis of a new family of complexes bearing an o-sulfonamide ligand which photo-isomerization properties were investigated. The coordination of these complexes to phosphorus derivatives could be modulated upon irradiation and this property was applied to the light-triggered aza-Morita-Baylis-Hillman reaction.The second part of this work describes the synthesis and study of a new family of ketal-substituted bridged azobenzenes which display an uncommon three-species photo-isomerization pattern, triggering an interconversion between stable conformational diastereomers with a good selectivity. These compounds offer promising perspectives for conformational control by light.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18952号 / 工博第3994号 / 新制||工||1615(附属図書館) / 31903 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 北川 進, 教授 杉野目 道紀, 教授 宮原 稔 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20936号 / 理博第4388号 / 新制||理||1630(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 杉山 弘, 教授 三木 邦夫, 教授 秋山 芳展 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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