Flow mediated dilation (FMD) is a non-invasive test that assesses endothelial health and nitric oxide bioavailability; it is commonly used to examine changes in vascular health due to disease or de-conditioning. Currently, a wide variety of protocols are being used to assess upper and lower extremity conduit artery health. The current project was embarked upon to gain a better understanding of the FMD protocols currently being used to asses conduit artery FMD and how these results impact our understanding of a participant’s vascular health. More specifically occlusion duration, cuff placement and artery location were examined in three commonly examined conduit arteries. The FMD responses in the brachial artery (BA), superficial femoral artery (SFA), and popliteal artery (PA) of ten healthy men, mean age of 27, after five and/or two-minutes of distal occlusion were examined. When the two-minute protocol was performed on the SFA and PA, low-resistance static calf exercise was added to augment the shear stimulus. It was hypothesized that percent FMD and shear stress responses of the SFA and PA would not be significantly different after five-minutes of occlusion, thereby allowing leg conduit artery FMD to be performed on either artery. It was further hypothesized that there would be no significant differences between the shear stress and percent FMD responses of the leg conduit arteries after five or two-minutes of occlusion; inferring that shorter occlusion durations when combines with ischemic muscle contractions can be used to assess SFA or PA FMD. With regards to comparisons between arm and leg conduit arteries, it was hypothesized that there would be significant between limb differences in baseline diameter, FMD and shear stress post five-minutes of distal occlusion. These differences will be used to better understand the effects of artery location and size on conduit artery FMD IV responses. Limitations with the traditional edge-detection method of determining arterial diameter prompted the creation of a new method of measuring artery diameter, the center-based method. It was hypothesized that there would be no significant differences in the percent FMD and time to FMD after five-minutes of BA occlusion (n=7). The results of the current study demonstrated that five-minutes of calf occlusion elicited a significant PA FMD but not a significant SFA FMD. FMD post two-minutes of PA occlusion with exercise was not significantly different than that produced by five-minutes of occlusion. Conversely, two-minutes of calf occlusion with exercise was unable to elicit a SFA FMD response. Significant differences in shear stress and FMD were reported between arm and leg conduit arteries, demonstrating different responses to five-minutes of distal occlusion due to artery size and location. Finally, no significant differences were noted between FMD and time to FMD when the center-based or edge-detection method was used. This study has demonstrated that the calf occlusion protocol was unable to elicit a FMD response in the SFA FMD; this occlusion location is only able to elicit a PA FMD response. Furthermore, two-minutes of occlusion with one-minute of exercise can be used in place of the five-minute protocol to examine PA FMD but not SFA FMD. Differences between arm and leg conduit arteries are noted and it has been suggested that this is likely due to leg conduit artery adaptations to gravity. Lastly, preliminary data suggest that the center-based method is an appropriate method of measuring conduit artery diameter.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24481号 / 医博第4923号 / 新制||医||1063(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 高橋 淳, 教授 髙橋 良輔, 教授 井上 治久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Sacred stones, or huacas, at the ancient Inca city of Machu Picchu integrated human ritual with the surrounding landscape. I argue that huacas defined the relationship between nature and ritual practice by forcing an esoteric choreography which involved specific postures of the participant in order to visually orient humans to significant natural features of the surrounding environment. Inca stonemasons refined the natural form of the huacas so that they mimic the contours of prominent landscape features such as mountain peaks. This dissertation documents 122 huacas at Machu Picchu using maps of the site to record the exact location of each stone. Every huacas is described in detail, including notation of the specific cardinal orientation; lines of sight established by reference points to prominent landscape features; and the specific posture required to view these lines of sight. The extensive number of huacas at Machu Picchu suggests a highly ritualistic city in which stones and caves were almost certainly considered metaphysical conduits between humans and the divine.

Subglacial processes that control the water pressure and flow determine the large-scale behavior of the overlying ice by regulating basal resistance. We implement a model in which a steady-state subglacial conduit system is surrounded by fully saturated porous media. We investigate branching in this system at fixed angles of 15 degrees, 30 degrees and 45 degrees to the direction of ice flow and further assess these systems by calculating the hydraulic potential gradient to determine conduit flow path. We solve our governing equations for porous media flow and allow ice infiltration of the pore space to occur at a critical effective stress N infiltration. For low values of N infiltration, ice infiltration of sediment allows these conduits to follow their original paths. Where insufficient ice infiltration occurs, the conduit path instead lies parallel to the direction of ice flow. Our results speak to the importance of incorporating small-scale processes into models of subglacial hydrologic networks.

Avalanche paths are unique ecosystems that represent a significant portion of the landscape in the northern Rocky Mountains. Frequent avalanche disturbance results in vegetative cover that is unlike the adjacent coniferous forest. These high relief environments have the potential to remove carbon from the atmosphere at rates differing from those of the surrounding forest, and to regulate matter and/or energy fluxes to downslope ecosystems. This thesis attempts to estimate organic carbon on south-facing avalanche paths in the southern portion of Glacier National Park, Montana. I am specifically interested in total organic carbon density, compartmental carbon density, and change in organic carbon over time as a function of shrub and tree diameter. Using an integrated sampling method, estimates of total organic carbon on avalanche paths appear to be different than those of the adjacent forest and similar to those of other shrub formation types in the area. However, the potentially moveable litter compartment is consistently larger. Organic carbon from shrub and trees growing on paths appears to be increasing at a continuous rate leading up to disturbance, while a typical individual's rate of increase appears to be slowing. The organic material temporarily stored on avalanche paths could serve as an important outside carbon source for near and distant aquatic ecosystems.

Ce travail de thèse effectué au Laboratoire d'Acoustique de l'Université du Maine s'inscrit dans le cadre d'une étude à caractère expérimental sur la propagation des ondes acoustiques dans des guides traités acoustiquement en présence d'un écoulement. Les guides d'onde considérés sont des conduits droits dont la paroi peut être localement modifiée. Les traitements pariétaux appliqués sont caractérisés globalement par leur impédance. Déterminer l'impédance de ces éléments permet d'en déduire l'atténuation sonore pour des applications industrielles possibles, telles que la réduction des nuisances sonores dans des pots d'échappement ou des réacteurs d'avion. <br />La présente étude se limite à des traitements à réaction dite locale, dont l'impédance est estimée en fonction de la fréquence.<br /><br />Une méthode basée sur la décomposition modale de la pression est exposée. La modélisation est adaptée aux différents traitements pariétaux étudiés et permet d'obtenir les caractéristiques de la transmission d'une onde acoustique. Les applications sont effectuées dans le cas de la propagation d'un mode plan, dans le cas où plusieurs modes sont considérés, ou enfin, dans le cas où le profil d'un écoulement non uniforme est pris en compte. Cette méthode est associée à une méthode inverse permettant d'estimer l'impédance des traitements pariétaux.<br /><br />Les résultats sont confrontés aux mesures réalisées. Les expériences ont été menées sur des bancs à écoulement où des mesures de matrice de diffusion sont réalisées à partir d'une méthode multi-microphonique classique.

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