published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy

For understanding the mechanisms of low level laser/light therapy (LLLT), accurate knowledge of light interaction with tissue is necessary. In order to have a successful therapy, laser energy needs to be delivered effectively to the target location which depending on the application can be within various layers of skin or deeper. The energy deposition is controlled by input parameters such as wavelength, beam profile and laser power, which should be selected appropriately. This thesis reports a numerical study that investigates the laser penetration through the human skin and also provides a scale for selection of wavelength, beam profile and laser power for therapeutic applications. First, human skin is modeled as a three-layer participating medium, namely epidermis, dermis, and subcutaneous, where its geometrical and optical properties were obtained from the literature. Both refraction and reflection are taken into account at the boundaries according to Snell’s law and Fresnel relations. Then, a three dimensional multi-layer reduced-variance Monte Carlo tool was implemented to simulate the laser penetration and absorption through the skin. Local profiles of light penetration and volumetric absorption densities were simulated for uniform as well as Gaussian profile beams with different spreads at 155 mW average power over the spectral range from 1000 nm to 1900 nm. The results showed that lasers within this wavelength range could be used to effectively and safely deliver energy to specific skin layers as well as to achieve large penetration depths for treating deep tissues, without causing any skin damage. In addition, by changing the beam profile from uniform to Gaussian, the local volumetric dosage could be increased as much as three times for otherwise similar lasers. In the second part of this thesis, a three-dimensional single-layer reduced-variance inverse Monte Carlo method was developed to find the optical properties of the skin using the experimental values of transmittance and reflectance. The results showed that both transmittance and reflectance scale well with transport optical thickness. Moreover, it was also shown that penetration depth is highly sensitive to the laser wavelength and varied within the range from 1.7 mm to 4.5 mm. / text

No description available.

Champlain Sea Clay (also known as Leda Clay) is a sensitive marine clay that was deposited within the limits of the Champlain Sea transgression during the final retreat of the Laurentide ice sheet. Upon isostatic rebound, the watersheds incised deep river valleys throughout the Ottawa region. These sensitive clay river banks have been shown to be highly susceptible to large retrogressive landslides. A cone penetration testing and hydrogeological program was developed in this thesis to characterize a retrogressive landslide along a creek valley consisting mainly of Champlain Sea Clay. As Champlain Sea Clay has been commonly shown to consist of banded layers, a 2 cm2 piezocone, and 5 cm2, 10 cm2 and 15 cm2 CPTu cones were used to demonstrate that the slightly larger 5 cm2 penetrometer was the most practical size for investigating landslides in Champlain Sea Clay. In doing so, the 5 cm2 cone was capable of high resolution stratigraphic profiling, locating remoulded layers for slip surface detection and characterizing the Champlain Sea Clay landslide near Ottawa. Due to the significant effects of the pore pressure distribution on slope stability and retrogressive behavior, a long term hydrogeological program was initiated which defined the ground water regime and real-time pore pressure data during a retrogressive landslide event. The seasonal change in the ground water regime from rapid snowmelt has shown to be a significant hydrogeological influence on triggering a retrogressive landslide along Mud Creek. With regular monitoring over multiple seasons, the seasonal pore pressure changes can be used to further understand the long term development of retrogressive landslides in Champlain Sea Clay. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-09-27 14:13:40.196

Orientador: João Carlos Pinheiro Ferreira / Banca: José Roberto Sartori / Banca: Nadja Susana Mogyca Leandro / Resumo: No presente estudo foram correlacionados os resultados das contagem de perfurações espermáticas na membrana perivitelínica externa de ovos incubáveis com as taxas de eclosão e fertilidade, objetivando-se analisar a possibilidade do uso dessa técnica como alternativa aos métodos tradicionais de avaliação da fertilidade, executados no incubatório. As avaliações foram realizadas a cada três semanas durante todo o período reprodutivo de um lote comercial de matrizes de corte da linhagem Avian Cobb 48, submetidas à monta natural a partir da 25a semana de idade. Foram realizadas 10 avaliações, sendo utilizados 30 ovos em cada avaliação. Foi realizada a extração, fixação e coloração da membrana perivitelínica externa para possibilitar a visualização das perfurações ao microscópio óptico. A idade da ave influenciou negativamente o número de perfurações espermáticas na membrana perivitelínica externa, bem como a taxa de fertilidade e de eclosão. Houve correlação positiva entre o número de perfurações espermáticas na membrana perivitelínica e a taxa de fertilidade (r= 0,885; P<0,05), assim como com a taxa de eclosão (r= 0,800; P<0,05). É possível inferir que a contagem de perfurações espermáticas pode ser utilizada como ferramenta de avaliação da fertilidade de ovos incubáveis / Abstract: In this study we correlated the results of counting sperm penetration in the outer perivitelline layer of hatching eggs to the fertility and hatching rates, aiming to examine the possibility of using this technique as an alternative to traditional methods of fertility evaluation, performed in the hatchery. The evaluations were performed every three weeks throughout the reproductive period of a flock of commercial broiler strain Cobb Avian 48, submitted to natural mating from the 25th week of age. Were performed 10 evaluations, 30 eggs were used in each assessment. Was extracted, fixed and stained outer perivitelline layer to enable viewing of holes in an optical microscope. The bird's age negatively influenced the number of sperm holes in the outer perivitelline layer and the fertility rate and hatching. A positive correlation between the number of sperm holes in the perivitelline layer and the fertility rate (r = 0.885, P <0.05), as well as the hatching rate (r = 0.800, P <0.05). It can infer that the sperm count of holes can be used as a tool for assessing the fertility of eggs hatching / Mestre

Ionospheric disturbance electric fields of magnetospheric origin play an important role in determining the global morphology and dynamics of the ionosphere of the Earth. In this work, we present a number of numerical simulations of the transient electric fields in the middle and inner magnetosphere and the ionosphere equatorward of the auroral zone caused by idealized changes in the magnetospheric driving parameters. For these studies, we u se the Rice Convection Model (RCM), a large computer code of the magnetosphere-ionosphere coupling which consistently computes the electric fields, currents, and plasma densities in the magnetosphere and the electric field and currents in the ionosphere in the quasi-static slow-flow approximation. We made substantial upgrades to the code, which include a module computing realistic solar EDY-produced ionospheric conductances and a new potential solver. Our upgraded version of the RCM also includes a time - varying magnetospheric magnetic field and a self-consistently estimated auroral zone. We first discuss numerical problems encountered in modeling electrodynamics of convection with a time-varying magnetic field, realistic ionospheric conductances, and a self-consistent auroral zone, and our solutions to those difficulties. We then present a number of "computer experiments" with the new version of the RCM with idealized changes in the magnetospheric parameters such as sudden changes in the cross polar cap potential drop, magnetic field reconfiguration corresponding to the overall changes in the high-latitude convection, as well as rotations of the electric field on the polar cap boundary. Prompt penetration ionospheric electric fields simulated with the upgraded RCM are shown to be consistent with the previous simulations. The new simulations and their results are discussed in the context of (1) possible contribution to the variability of the ionospheric electric fields, and (2) role of time-varying magnetic field on the characteristic lifetimes of prompt penetration electric fields at subauroral, middle, and low latitudes.

Thesis (M. Sc.)--University of Hong Kong, 2002.

No description available.

This study aims to elucidate the process and mechanism of sperm penetration through eggs of Penaeus monodon. Sperm penetration of the vitelline envelopes (VEs) of P. monodon eggs were observed with the scanning electron microscope. The characteristics of sperm proteases in the sperm extracts from seminal receptacles of females were analysized. In P. monodon, mating and sperm transfer to the thelycum of female occur soon after maturity moult. Females store the sperm in the seminal receptacles. At spawning, they release stored sperm and eggs simultaneously into the water column. The outermost investment of a newly spawned egg is the VE. Sperm bind to the VE via the tip of their anterior spike. They rapidly undergo the acrosome reaction, which composes of depolymerization of the spike and exocytosis of the acrosome vesicle, pass through the VE and become bound to the egg oolemma. The isolated sperm suspended in artificial seawater were disrupted by sonication on ice. The supernatants after microcentrifuged were collected as sperm extracts. Sperm extracts were analyzed by gelatin SDS-PAGE. Sperm extract from sperm isolated from seminal receptacles of females showed clear bands of protease activity, whereas sperm extract from vas deferens and spermatophore of males did not. This results indicated that sperm of P. monodon do proceed capacitation in the seminal receptacles, and obtain sperm protease activity after capacitation. Using fluorescent peptidyl-MCA as sperm protease substrates, high trypsin-like and aminopeptidase-like activities were observed in sperm extracts. The sperm protease activity was inhibited by trypsin inhibitors aprotinin, p-aminobenzamidine (PAB), soybean trypsin inhibitor (SBTI), N-£\-p-tosyl-L-lysinechloromethyl ketone (TLCK); but was not inhibited by chymotrypsin inhibitor N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and metalloprotease inhibitor 1,10-phenanthroline (1,10-P). The results indicated that sperm undergo the acrosome reaction and release sperm proteases including trypsin-like protease, which has been implicated in facilitating sperm passage through vitelline envelope. Sperm proteases were highly active in the weak base environment, exhibiting maximum activity at pH 8.0. The protease activities were enhanced by addition of calcium chloride and magnesium chloride in the incubation medium.

In order to understand the input of South China Sea Water (SCSW) onto the Kuroshio and the distributions of carbonate parameters in Kuroshio Water (KW), the temperature, salinity, pH and TCO2 were measured for the seawater samples collected from the Kuroshio regime off eastern Taiwan during the cruise ORI 650 in July 2002. The distributions of temperature and salinity show that a front existed approximately along 123.5&#x00BA;E, which separated the influenced KW by SCSW from typical KW. East of this front the water is characterized by temperature and salinity of KW, while west of it the water was mainly a mixture of the SCSW and the KW. After flowing out from the Luson Straint, the SCSW deflected northward along the east cost of Taiwan, and continuously mixed with the KW. The mixing of SCSW with KW could be traced northward as far as 22&#x00BA;N and reach as deep as 1250m. Based on the measured carbonate data, the calculated IC/OC ratio ranges from 22% to 23% in the deep water of the Kuroshio region. Additionally, the penetration depth of anthropogenic CO2 was estimated to be about 1200m by using Chen¡¦s equation (Chen et al., 1986). Furthermore, the difference of pCO2 between atmosphere and surface seawater was evaluated to be about -5matm, indicating that the surface water in the study area was nearly saturated with pCO2 during the sampling period.