In the quest to understand the physiological basis of postharvest needle loss in balsam fir, we hypothesized that, volatile terpene compounds (VTCs) have a role in needle abscission. This study focused on understanding the role of VTC’s in postharvest needle abscission. We demonstrated that balsam fir contains twelve VTCs with varying concentrations depending on whether it is a seedling or a clonal tree branch. Total VTC concentration consistently increased prior to needle loss. Five specific VTCs (?-Pinene, ?-Terpinene, Fenchyl acetate, Camphene and 3-Carene) have been identified as possible key signal molecules in needle abscission. VTCs were synthesized independently of ethylene, thus VTCs can be a possible signal molecule to needle abscission. Exposure of branches to ethylene showed an increase in both ethylene and VTC however, total VTC concentration was below the threshold required to cause needle abscission.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 260-267). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1941. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Jatobà (Hymenaea courbaril l.) has an extensive history of use by natives of tropical forests, its fruits are composed of essential oils, tannins, bitter substances, resinous materials and pectic, starch and sugars. The objective of this study was to evaluate the antimicrobial activity of the essential oil extracted from the peel of fruits of Hymenaea courbaril l. (OEHc) and its mechanism of action on OSSA reference strains S. aureus (S. aureus ATCC 6538P and S. aureus 14458). For the evaluation of antimicrobial activity antimicrobial potential were determined from OEHc Inhibitory Concentrations (MIC) and Minimum Lethal (CLM) from OEHc, the effect of time of exposure to OEHc, OXA and OEHc associations-OXA, OEHc modulator effect on activity of antibiotics (ATB) for clinical use, and the OEHc action on exponential and stationary phases of growth and in growth stationary phase in the presence of chloramphenicol. The OEHc action mechanism was verified by crystal violet uptake, release of genetic material, determination of potassium ion efflux and for assessing the microbial morphology by atomic force microscopy. It was also evaluated the action of sub-inibitÃrias concentrations of OEHc on expression of virulence factors (catalase, coagulase, DNAse, lipase, and hemolysin) and stability of antimicrobial activity of OEHc at different pH. OEHc inhibited the growth of S. aureus strains ATCC 6538P (CIM = CLM = 2.5 mg/mL) and S. aureus ATCC 14458 (CIM = 2.5 mg/mL; CLM = 5 mg/mL). The CLM from OEHc was able to derail the OSSA strains tested in 8 (S. aureus ATCC 6538P) and 24 hours (S. aureus ATCC 14458) and the CIM inhibited the growth of S. aureus ATCC 14458 until 48 hours of exposure. The modulatory action of the antibiotic activity of OEHc clinical use ranged with the ATB and with the strain tested. OEHc associations-OXA tested was found a predominance of synergistic effects and indifferent to the OSSA strains tested. The OEHc was able to reduce the number of viable cells at all stages microbial growth. Its greater efficiency in the presence of CLO suggests a mechanism of action independent of the cellular metabolism. The OEHc was able to promote the increased uptake of crystal violet, the release of genetic material and the efflux of potassium ions, causing also changes in bacterial morphology, suggesting that its target of action is the cell wrap. However, the inhibition of the expression of virulence factors can indicate the participation of other targets on OEHc action, as the synthesis of macromolecules. The antimicrobial activity of OEHc about strains OSSA is potentized in alkaline pH. The results show that the OEHc has a good antimicrobial activity on the species Gram-positive S. aureus, with action mechanisms mediated by the occurrence of damage in microbial wrap with loss of intracellular material and inhibition of the synthesis of macromolecules, revealing its synergistic modulator effect when associated with oxacillin and other antibiotics of clinical use. / O Jatobà (Hymenaea courbaril L.) possui um amplo histÃrico de utilizaÃÃo pelos indÃgenas de florestas tropicais, seus frutos sÃo compostos por Ãleos essenciais, taninos, substÃncias amargas, matÃrias resinosas e pÃcticas, amido e aÃÃcares. O objetivo deste estudo foi avaliar a atividade antimicrobiana do Ãleo essencial extraÃdo da casca de frutos da Hymenaea courbaril L. (OEHc) e o seu mecanismo de aÃÃo sobre cepas OSSA de referÃncia de S. aureus (S. aureus ATCC 6538P e S. aureus 14458). Para a avaliaÃÃo da atividade antimicrobiana foram determinados o potencial antimicrobiano do OEHc, as ConcentraÃÃes InibitÃria (CIM) e Letal MÃnimas (CLM) do OEHc, o efeito do tempo de exposiÃÃo ao OEHc, a OXA e as associaÃÃes OEHc-OXA, o efeito modulador do OEHc na atividade de antibiÃticos (ATB) de uso clÃnico, e a aÃÃo do OEHc na fases de crescimento exponencial e estacionÃrio e na fase de crescimento estacionÃrio na presenÃa de cloranfenicol. O mecanismo de aÃÃo do OEHc foi verificado por captaÃÃo do cristal violeta, liberaÃÃo de material genÃtico, dosagem do efluxo de Ãons potÃssio e pela avaliaÃÃo da morfologia microbiana por microscopia de forca atÃmica. TambÃm foi avaliada a aÃÃo de concentraÃÃes sub-inibitÃrias do OEHc na expressÃo de fatores de virulÃncia (catalase, coagulase, hemolisina, lipase e DNAse) e a estabilidade da atividade antimicrobiana do OEHc em diferentes pH. OEHc inibiu o crescimento das cepas de S. aureus ATCC 6538P (CIM = CLM = 2,5 mg/mL) e S. aureus ATCC 14458 (CIM = 2,5 mg/mL; CLM = 5 mg/mL). A CLM do OEHc foi capaz de inviabilizar as cepas OSSA testadas em 8 horas (S. aureus ATCC 6538P) e 24 horas (S. aureus ATCC 14458) e a CIM inibiu o crescimento de S. aureus ATCC 14458 atà 48h de exposiÃÃo. A aÃÃo moduladora do OEHc na atividade de antibiÃticos de uso clÃnico variou com o ATB e com a cepa testada. Para as associaÃÃes OEHc-OXA testadas foi encontrada uma predominÃncia de efeitos sinÃrgicos e indiferentes para as cepas OSSA testadas. O OEHc foi capaz de reduzir o nÃmero de cÃlulas viÃveis em todas as fases crescimento microbiano. Sua maior eficiÃncia na presenÃa de CLO sugere um mecanismo de aÃÃo independente do metabolismo celular. O OEHc foi capaz de promover o aumento da captaÃÃo do cristal violeta, da liberaÃÃo de material genÃtico e do efluxo de Ãons potÃssio, provocando tambÃm alteraÃÃes na morfologia bacteriana, sugerindo que seu alvo de aÃÃo seja o envoltÃrio celular. No entanto, a inibiÃÃo da expressÃo de fatores de virulÃncia pode indicar a participaÃÃo de outros alvos na aÃÃo do OEHc, como a sÃntese de macromolÃculas. A atividade antimicrobiana do OEHc sobre cepas OSSA à potencializada em pH alcalino. Os resultados encontrados mostram que o OEHc possui uma boa atividade antimicrobiana sobre a espÃcie Gram-positivo S. aureus, com mecanismos de aÃÃo mediados pela ocorrÃncia de danos no envoltÃrio microbiano com perda de material intracelular e inibiÃÃo da sÃntese de macromolÃculas, revelando seu efeito modulador sinÃrgico quando associados a oxacilina e outros antibiÃticos de uso clÃnico.

Les implants cardiaques tels que les défibrillateurs implantables sont des appareils permettant de sauver la vie dans le cas de troubles de l’arythmie cardiaque soudaine. Tandis que dans le cas des attaques cardiaques, les implants CRT sont utilisés pour rétablir la cadence de la contraction cardiaque. De tels traitements consistent en l’application de stimulations locales au tissue cardiaque via des électrodes se trouvant dans les sondes de stimulation. Ces dernières se présentent soit dans une configuration unipolaire ou bipolaire qui ont prouvé leur efficacité pour stimuler le ventricule droit et l’oreillette droite ; des études ont montré l’efficacité de la sonde multi-électrode dans la stimulation du ventricule gauche indispensable pour la resynchronisation cardiaque. Cette thèse traite de la conception et l’optimisation d’un système multi-électrodes capable d’éviter les limitations et les contraintes liées à la stimulation du ventricule gauche. Tout d’abord, une réalisation de ce système cette est présentée et fabriqué dans une technologie 0.18 µm. Le circuit a également un protocole de communication spécifique. Il permet une opération basse consommation et une configuration rapide. Ensuite, la conception et la réalisation d’une unité de configuration par défaut est présentée. Cette unité assure la compatibilité de notre sonde avec les stimulateurs cardiaques du marché. Finalement, une étude pour l’adaptation et l’intégration des technologies mémoire non-volatile dans la sonde est présentée. De telles technologies améliorent considérablement le système en évitant le besoin de reconfiguration des sondes et en conséquence réduire la latence et la consommation. / Cardiac implants like ICD are life saving devices for cardiac arrhythmias. In other conditions like heart failure, CRT implants are prescribed to restore the heart rhythm. Such treatment consists of the delivery of electrical stimuli to the cardiac tissue via electrodes in the stimulation lead. Conventionally the stimulation lead come either in unipolar or bipolar configuration which have been found to be sufficient for pacing the right atrium and right ventricle, studies have shown the benefits of a multi-electrode system for pacing left ventricle essential for cardiac resynchronization. This thesis discusses the design and optimization of a multi-electrode system capable of alleviating the limitations and constraints related to left ventricular stimulation. We first present implementation of such system that was taped out in 0.18 µm technology. The chip also features a specially designed communication protocol which enables low power operation and quick configuration. Thereafter we present the design and implementation of a default connection unit to ensure the compatibility of our multi-electrode lead with in the market. This unit was taped out in 0.18 µm technology. Finally we present a proof of concept study for the adaptation and integration of non-volatile memory technologies within the multi-electrode system. The employment of such technologies enhanced our multi-electrode system by eliminating the repetitive configuration of electrodes, thereby saving power and reducing latency. This also included smaller area and compatibility with any pacemaker in the market. Through simulations we proved the feasibility of these technologies for our implant applications.

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No description available.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

À mesure que les technologies de l'information (IT) continuent de croître, les dispositifs mémoires doivent évoluer pour répondre aux exigences du marché informatique. De nos jours, de nouvelles technologies émergent et entrent sur le marché. La mémoire Resistive Random Access Memory (RRAM) fait partie de ces dispositifs émergents et offre de grands avantages en termes de consommation d'énergie, de performances, de densité et la possibilité d'être intégrés en back-end. Cependant, pour être compétitif, certains problèmes doivent encore être surmontés en particulier en ce qui concerne la variabilité, la fiabilité et la stabilité thermique de la technologie. Leur place sur le marché des mémoires est encore indéfinie. En outre, comme le principe de fonctionnement des RRAM dépend des matériaux utilisés et doit être observé à la résolution nanométrique, la compréhension du mécanisme de commutation est encore difficile. Cette thèse propose une analyse du principe de fonctionnement microscopique des CBRAM à base d'oxyde basé sur des résultats de caractérisation électrique et de simulation atomistique. Une interdépendance entre les performances électriques des RRAM et certains paramètres matériaux est étudiée, indiquant de nouveaux paramètres à prendre en compte pour atteindre les spécifications d'une application donnée. / As Information Technologies (IT) are still growing, memory devices need to evolve to answer IT market demands. Nowadays, new technologies are emerging and are entering the market. Resistive Random Access Memory (RRAM) are part of these emerging devices and offer great advantages in terms of power consumption, performances, density and the possibility to be integrated in the back end of line. However, to be competitive, some roadblocks still have to be overcome especially regarding technology variability, reliability and thermal stability. Their place on memory market is then still undefined. Moreover, as RRAM working principle depends on stack materials and has to be observed at nanometer resolution, switching mechanism understanding is still challenging. This thesis proposes an analysis of oxide-based CBRAM microscopic working principle based on electrical characterization results and atomistic simulation. Then, an interdependence between RRAM electrical performances as well as material parameters is studied to point out new parameters that can be taken into account to target specific memory applications.

M.Tech. (Chemical Engineering) / Increasing pressure on industry from national and international communities for more environmentally friendly operations has generated a drive towards the use of ‘green’ absorbents in the removal of volatile organic compounds from contaminated air streams. The objective of this work was to investigate the use of ester solvents, especially biodiesel esters, as suitable ‘green’ scrubbing solvents for the absorption of volatile organic compounds (VOCs) from gaseous waste streams. The objective was accomplished by investigating the nature of molecular interactions between ester solvents and various families of VOC solvents, and by studying the effect of temperature on absorption, through the analysis of infinite dilution activity coefficients. Activity coefficients were computed with a Microsoft Excel generated spread sheet using Modified UNIFAC Dortmund (1987) as a thermodynamic predictive model. Results show that non-polar solutes are more soluble in long chain ester solvents whilst polar solutes absorb easier in short chain ester solvents. The solubility of non-polar solutes decreases with increasing ester solvent unsaturation, whilst the opposite is true for polar solutes in esters. Short chain length non-polar solutes are more soluble than long chain length non-polar solutes in ester solvents, whilst the opposite trend occurs for polar solutes in ester solvents. An increase in branching of polar solutes results in the solute behaving more like a non-polar solute. Unfortunately UNIFAC models fail to account for functional group proximity effects, which may result in inaccurate results for systems involving highly branched solutes. However given that the purpose of this study was only to establish trends for generating an understanding of molecular interactions between the solutes and the solvent, it was acceptable to assume that these inaccuracies would be minor for the intended purpose. It was found that activity coefficients of ester/ solute interactions generally tend towards ideality with increasing temperature with the exception of alkanes and the nitrogen based VOCs, as well as tetrahydrofuran and tetrahydropyran, methacrolein and organic acid/ unsaturated ester interactions. In the case of the alkanes, tetrahydrofuran and tetrahydropyran, high-temperature absorption is preferred whilst for methacrolein lower temperature absorption is preferred. It was concluded that ester solvents ,especially biodiesel esters, are well suited for the removal of non-polar to moderately polar VOC solutes from waste gas streams due to the favourably low activity coefficients obtained for these ester/ solute interactions. The results presented in this report are comprehensive and can assist in making informed decisions in using biodiesel as a scrubbing solvent.