xiii, 129 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Surface plasmon polaritons (SPPs) are collective electron excitations with attendant electromagnetic fields which propagate on a metal-dielectric interface. They behave, in many ways, as model two-dimensional electromagnetic waves. However, because the evanescent field of the SPPs extends a short distance outside the interface, a near-field probe can modify the wave propagation. We use this behavior to study both SPP scattering within the plane of the interface and also the transition to free-space propagation out of the plane. We have, in particular, studied the multiple scattering of SPPs excited on rough silver films. Our laboratory possesses apertureless near-field scanning optical microscopes (A-NSOMs), the probes of which can act as an in-plane scatterer of SPPs. Subsequent momentum-conserving decays of the SPPs generate an expanding hollow cone of light to which information about the direction and phase of the SPPs on the surface is transferred. A focus of our studies has been SPP multiple scattering when one of the scatterers (the tip) can move. This problem is very closely related to a similar problem in mesoscopic electronic transport, involving "universal conductance fluctuations". It is also related to various radar-detection, microwave communications and medical imaging problems. In parallel with actual experimental measurements, we have also conducted extensive Monte Carlo simulations of the scattering. Multiple scattering leads to the appearance and detection of "speckle" in the far field. A speckle field, however, is more properly considered in terms of its embedded optical vortices and so we have used holographic techniques to study these. We have demonstrated that vortices can be manipulated, created and destroyed by movement of the STM probe tip. Optical vortices are an example of the effect of "geometric" or "topological" phase in physics and as such link the trajectory of a parameter in one space to the phase observed in another. In our case, the trajectory of the A-NSOM tip parallel to the sample surface plane generates topological phase in the far field, manifestations of which are vortices. / Committee in charge: Stephen Kevan, Chairperson, Physics; Stephen Gregory, Advisor, Physics; Michael Raymer, Member, Physics; David Strom, Member, Physics; Mark Lonergan, Outside Member, Chemistry

A seminal study by Morganroth et al (1975) demonstrated a differential pattern of cardiac adaptation with prolonged exercise training; of eccentric pattern of left ventricular hypertrophy (LVH) in endurance trained athletes (ET) and concentric LVH in resistance trained athletes (RT). Specific inconsistencies related to the nature of any adaptation to RT; the value of new imaging technologies; the relative importance of scaling of cardiac data for differences in body size; the impact of training on the right ventricle (RV) and the fit of differential pattern of adaptation in athletes with Black ethnicity have driven the rationale for the studies included in this thesis. Study one employed meta-analysis techniques to critically evaluate the evidence base supporting or refuting that MH exists in elite male Caucasian ET & RT. Modern echocardiographic techniques were used to test whether a dichotomous LV and RV structural as well as global and regional functional adaptation was apparent in elite Caucasian ET & RT in studies 2 & 3. The final study (exploratory) was to characterize the athletic heart phenotype in a homogenous population of elite RT of West African origin (WRT) to provide new insight in relation to cardiac adaptation and ECG characteristics in non-Caucasian athlete groups. Allometric scaling approach was deployed to index LV and RV data for individual body variance in body size. The novel findings of this thesis; larger LV data in ET (LVMg: ET 232 (200 to 260), RT 220 (205 to 234), CT 166 (145 to 186)) but no concentric hypertrophy in RT within the meta-analysis, predominance of normal geometry in male athletes (65% of ET and 95% of RT) and the lack of concentric pattern of hypertrophy in RT in a cross-sectional study; no RV adaptation in RT athletes (RVD1mm: ET 45 ± 5 (39 to 57), RT 40 ± 5 (32 to 51) CT 39 ± 4 (31 to 45)); no LV or RV adaptation in WRT athletes; the importance of appropriate scaling of cardiac parameters; provide a useful re-evaluation of concepts and models in the athletic heart literature. The findings have important implications for cardiovascular screening of athletes.

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Agradecemos a compreensão. on 2018-05-22T11:07:47Z (GMT) / Submitted by Michelli Fenerich (michellifenerich@hotmail.com) on 2018-05-23T00:06:49Z No. of bitstreams: 1 Dissertação Michelli Fenerich.pdf: 839583 bytes, checksum: 4eb04bc52d571c22b951ce3b11e0a705 (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-05-23T16:47:59Z (GMT) No. of bitstreams: 1 fenerich_m_me_jabo.pdf: 839583 bytes, checksum: 4eb04bc52d571c22b951ce3b11e0a705 (MD5) / Made available in DSpace on 2018-05-23T16:47:59Z (GMT). No. of bitstreams: 1 fenerich_m_me_jabo.pdf: 839583 bytes, checksum: 4eb04bc52d571c22b951ce3b11e0a705 (MD5) Previous issue date: 2018-04-12 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma doença de origem genética, muito prevalente em cães da raça Boxer. Histologicamente ocorre atrofia dos cardiomiócitos do ventrículo direito (VD) e consequente infiltração fibroadiposa, levando ao aparecimento de arritmias ventriculares. Mesmo sendo as alterações miocárdicas microscópicas em sua maioria, estudos recentes têm identificado disfunção contrátil do ventrículo direito, mesmo em estágios iniciais da doença em humanos, tanto por técnicas convencionais de ecocardiografia quanto por técnicas mais avançadas, como no caso do speckle tracking. Por isso, o objetivo deste estudo foi avaliar se há disfunção miocárdica de VD detectável pela ecocardiografia convencional e pela técnica de speckle tracking bidimensional em cães da raça Boxer portadores da CAVD. Para tanto, utilizou-se cães da raça Boxer com idade superior a quatro anos, distribuídos em dois grupos de acordo com o resultado da avaliação Holter (GC: < 50 EVs/24h, n=11 e GD: > 100 EVs/24h, n=11). Os animais foram submetidos a ecocardiografia e avaliou-se diâmetro e comprimento interno do VD em sístole e diástole, encurtamento fracional da área do VD (FAC), excursão sistólica do plano anular da tricúspide (TAPSE), velocidade miocárdica sistólica do ânulo lateral da tricúspide derivada do Doppler tecidual (S’) e deformação (strain) e taxa de deformação (strain rate) longitudinal global da parede livre do VD, derivados da análise por speckle tracking. As variáveis foram comparadas entre os grupos pelo teste t de Student e de Mann-Whitney e a correlação entre variáveis ecocardiográficas convencionais e de speckle tracking e o número e severidade das arritmias pelo teste de correlação de Pearson, com nível de significância de 5%. Os grupos não foram estatisticamente diferentes e não houve correlação entre os dados. Os resultados da pesquisa demonstraram que a ecocardiografia, tanto na avaliação do VD por índices sistólicos convencionais quanto por aqueles derivados da técnica de speckle tracking não foram capazes de detectar disfunção miocárdica do VD em Boxers portadores de CAVD. / Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disease with a high prevalence in Boxer dogs. Histologically, right ventricle (RV) cardiomyocytes’ atrophy occurs, and thus fibrofatty infiltration, triggering ventricular arrhythmias. Although the myocardial changes are mostly microscopic, recent studies in human beings have identified right ventricular systolic dysfunction even in the early stages of ARVC, both by conventional echocardiographic techniques and advanced methods, such as speckle tracking. Therefore, the aim of this study was to investigate if RV myocardial dysfunction is present in Boxers affected by ARVC, evaluated by conventional echocardiography and bidimensional speckle tracking technique. For this purpose, Boxers older than four years were recruited, and based on 24-hour Holter recording were divided in groups: GC:< 50 VPC/24h (n=11), or GD: > 100 VPC/24h (n=11). The following echocardiographic parameters were analyzed: RV internal dimension during systole and diastole; RV fractional area change (FAC); tricuspid annular plane systolic excursion (TAPSE); myocardial systolic velocity of lateral tricuspid annulus (S’), and global longitudinal strain and strain rate. Groups were compared by Student’ t-test or Mann-Whitney test according distribution, and correlation between conventional and speckle tracking echocardiographic variables, as well as number and severity of the ventricular arrhythmias were accomplished by the Pearson test, assuming a level of significance at 5%. Groups were considered similar, and there was no correlation among the evaluated parameters. Our findings suggesting that the echocardiographic evaluation of RV, either by conventional and speckle tracking techniques, were not able to detect systolic myocardial dysfunction in Boxers affected by ARVC. / FAPESP: 16/14800-7

INTRODUCTION: As populations are adopting a Western lifestyle, with high intake of dietary sugar and fat and low physical activity, the risk of developing Type 2 Diabetes is only increasing dramatically. Diabetes leads to drastic alterations within the body, primarily leading to neuropathies, nephropathies and retinopathies. As the prevalence of diabetes increases, it is important to understand the threat that it poses to the retina, and ultimately, vision. OBJECTIVE: We plan to compare the retina of diabetic patients with retinopathies to normal, healthy patients to understand the differences between them. We will be using a novel imaging technique, called Laser Speckle Flowgraphy, which provides the Mean Blur Rate, a value directly related to the blood flow velocity within the retina, specifically the optic nerve head. Using the calculated Mean Blur Rate, this study will quantify baseline blood flows in patients with diabetic retinopathies. This project aims to understand and differentiate the Mean Blur Rate of healthy patients and diabetic patients, including inter-patient and intra-patient comparisons, as well as changes in the Mean Blur Rate over time. The potential influence of treatment factors, such as intravitreal injection treatment or laser treatment, or demographic factors, such as age and race, on the Mean Blur Rate of diabetic retinopathy patients will also be evaluated. By understanding the difference in the retinas of diabetic patients and healthy patients, we can work towards preventing the loss of vision and function. METHODS: A total of 25 Type 2 diabetic patients with a diabetic retinopathy equaling 46 eyes were compared to 20 healthy patients, equaling 40 eyes. We collected the Mean Blur Rate for comparison between the two populations. Data was compared with correlation, t-test and ANOVA studies to find whether demographic or treatment variables influenced the Mean Blur Rate of diabetic retinopathy patients. RESULTS: We found a difference between the Mean Blur Rate, and thus blood flow, between the retina of diabetic and healthy patients. Diabetic patients tended to have a lower flow, presumably attributable the effects of hyperglycemia on blood circulation. Diabetic patients also have a significant difference in the Mean Blur Rate between both of their eyes, indicating that their hyperglycemia may affect both eyes differently (p<0). There was significant variability within both diabetic retinopathy patients and normal, healthy patients (p<0 for healthy patients and p<0.001 for diabetic patients). This is expected as blood circulation can be affected by a variety of factors other than disease status. We also found that the MBR of diabetics who were treated with intravitreal injections was on average higher than those who had not received intravitreal treatment. (p<0.05) CONCLUSION: Our study highlights how diabetic retinopathy impacts retinal blood flow, as well as showcases how Laser Speckle Flowgraphy can be used as a reliable method to measure and compare retinal blood velocities. Further studies are needed to understand how exactly diabetes affects blood circulation, although several theories are currently available. We also found a relation between previous intravitreal injection history and the blood flow velocity, but other studies have had mixed results on how exactly these injections alter the blood flow within the retina. Future studies can be conducted to better understand this relationship and uncover whether the effect on blood flow velocity is related to the drug used for the intravitreal injection or some other factor.

Optical sensing and imaging inside heavily scattering media are of intense interest because of their importance in biomedical, environmental, and material inspection applications. When coherent light interacts with scatterers, bright and dark intensity regions form, a phenomenon known as speckle. Often viewed as being detrimental, speckle can be exploited to yield useful information with a correlation analysis.<br> <br>A coherent method is presented for the imaging of a hidden object moving within thick and randomly scattering media using speckle intensity correlations over object position, with the possibility of accessing super-resolution information. With prior information about the moving object's motion, spatial speckle intensity correlations as a function of object position can reveal the hidden object's relative refractive index distribution. Our experimental evidence shows that it is feasible to image complex aperture-type moving objects and circular patches inside scatter that is a magnitude of order heavier than other comparable imaging modalities. Images of the moving object were obtained from speckle intensity correlation data using phase retrieval. Biological tissue was used to demonstrate the possibility of in vivo deep-tissue imaging. Speckle intensity correlations are shown to be sensitive to both the scattering strength of the embedded object and the environment, both of which are useful for sensing. We present a general theory that describes this influence of the background scattering medium and allows for imaging a hidden moving object. Additionally, we present a method to improve the sensitivity of speckle correlography in remote optical metrology. By placing a scattering slab in front of the detector, we demonstrate enhanced sensitivity, detecting the subwavelength in-plane displacement of a remote diffuse object.

Theory and methods of processing speckle interferometry data from close visual binary stars are presented and implemented. The effects of the optical systems used for observing close visual binary stars are explained and simulated from both the geometrical and physical optical viewpoints. The atmospheric phase distortion and shot noise responsible for the observed speckle patterns are simulated. The deconvolution technique originally presented by Labeyrie is implemented to extract astrometric data from close visual binary stars. This method is applied to both simulated and experimental data from Kitt Peak National Observatory as validation. Parts of the deconvolution process are optimized to allow for near real time calculations in an automated observatory.

Laser speckle photography is an experimental technique which provides a non-contract means for direct measurement of in-plane displacements of objects subjected to different loading conditions. It requires a camera system to record two images of the object that are illuminated with laser light on a high resolution film. The double-exposure film (specklegram) is a permanent record of the displacement information of the object. Point-by-point analysis of the specklegram will yield the displacement data, but requires considerable time to complete the data reduction. An automated data analysis system is developed and described in this report. He-Ne laser and computer-controlled translation stages holding the specklegram represent the first part of the system. A linear diode sensor is used to digitize the generated fringe pattern. Finally, a microcomputer and a spectrum analyzer are used to perform the analysis. The system has been successfully applied to the computation of displacements of a cantilever beam. Comparisons to theoretical results indicate that the system is indeed a viable one and may be sued for a more complex displacement analysis.

An experimental and a theoretical analysis for a laser beam propagating through multiple phase screens was performed. The theoretical analysis showed that the statistics for the intensity fluctuations, which can be predicted by the HK and the I-K distributions, could be derived from a multiplicative process using statistical distributions derived from Gaussian statistics. For the single phase screen experiment, the experimental normalized moments were compared with the normalized moments of both the HK and I-K distributions . In addition, the intensity data was lowpass filtered to yield moments that are predicted by the gamma distribution. The single phase screen data was segmented into small time intervals, and all time segments with approximately the same variance were grouped together into bins to yield normalized moments for each bin that are predicted by the Rician distribution. Also, the normalized moments for two and three phase screen experiments were measured. Finally, a computer program was written to simulate K distributed noise from two independent Gaussian noise sources.

This thesis presents fundamental research in the field of laser vibrometry for the application to vibration measurements. A key concern for laser vibrometry is the effect of laser speckle which appears when a coherent laser beam scatters from an optically rough surface. The laser vibrometer is sensitive to changes in laser speckle which result from surface motions not in the direction of the incident beam. This adds speckle noise to the vibrometer output which can be indistinguishable from the genuine surface vibrations. This has been termed ‘pseudo-vibration' and requires careful data interpretation by the vibration engineer. This research has discovered that measurements from smooth surfaces, even when no identifiable speckle pattern is generated, can produce noise and therefore reference to speckle noise, in such circumstances, is inappropriate. This thesis has, therefore, adopted the more general term of pseudo-vibration to include noise generated from any surface roughness or treatment, i.e. including but not limited to speckle noise. This thesis develops and implements novel experimental methods to quantify pseudovibration sensitivities (transverse, tilt and rotation sensitivity) with attention focussed on commercially available laser vibrometers and consideration is given to a range of surface roughnesses and treatments. It investigates, experimentally, the fundamental behaviour of speckles and attempts to formulate, for the first time, a relationship between changes in intensity to pseudo-vibration sensitivity levels. The thesis also develops and implements models for computational simulation of pseudo-vibrations using the fundamental behaviour of speckles. The combination of experimentation and simulation improves current understanding of the pseudo-vibration mechanisms and provides the vibration engineer with a valuable resource to improve data interpretation. Two experimental methods of quantifying pseudo-vibration sensitivity are developed and successfully applied in the evaluation of transverse, tilt and rotation sensitivity for two models of commercial laser vibrometer. These evaluations cover both single beam (translational vibration measurement) and parallel beam (for angular vibration measurement) modes. The first method presented requires correction of the vibrometer measurement with an independent measurement of genuine velocity to produce an iii apparent velocity dominated by the required noise components. The second method requires a differential measurement using two vibrometers to cancel common components such as genuine velocity, leaving only uncorrelated noise from each measurement in the resulting apparent velocity. In each case, a third measurement is required of the surface motion component causing pseudo-vibration and this is used to normalise the apparent velocity. Pseudo-vibration sensitivity is then presented as a map showing the spectral shape of the noise, as a mean and standard deviation of harmonic peaks in the map and as a total rms level across a defined bandwidth. The simulations employ a novel and effective approach to modelling speckle evolution. Transverse and tilt sensitivity are predicted for the first time and are verified by the experimental study. They provide the vibration engineer with the potential to estimate pseudo-vibrations using a simple piece of software. The laser beam spot diameter has a large influence on the pseudo-vibration sensitivity. Transverse sensitivity has been quantified as around 0.03% and 0.01% (per order) of the transverse velocity of the surface for beam spot diameters of 100 μm and 600 μm respectively. Larger beam spots have been shown to significantly reduce transverse sensitivity and measurements from smoother surfaces have also shown a reduced level of transverse sensitivity. Tilt sensitivity has been quantified at about 0.1 μms-1/degs-1 and 0.3 μms-1/degs-1 (per order) of angular velocity of the surface for beam spot diameters of 100 μm and 600 μm respectively. Smaller beam spot diameters significantly reduce tilt sensitivity. The surface roughness or treatment has been shown to have little effect on the level of tilt sensitivity. Rotation sensitivity has been quantified at approximately 0.6 μms- 1/rads-1 and 1.9μms-1/rads-1 (per order) of rotation velocity of the rotor for 90 μm and 520 μm. Smaller beam spot diameters have shown a significant reduction in rotation sensitivity and measurements on smoother surfaces have shown a reduced rotation sensitivity. Focussing the laser beam approximately on the rotation axis has also shown a significant reduction in rotation sensitivity. Parallel beam rotation sensitivity has been quantified at 0.016 degs-1/rads-1 and it is demonstrated that this can adequately be estimated using the single beam rotation sensitivity.

La surexposition aux rayonnements ionisants est actuellement une préoccupation croissante des cliniciens. Lors d'une exposition externe, la peau est le premier tissu lésé. Or, il n'existe pas d'outil fiable qui permette de diagnostiquer l'atteinte tissulaire. L'objectif de ce travail est donc de montrer la possibilité d'utiliser une méthode non invasive pour l'aide in vivo au diagnostic et au pronostic du syndrome cutané d'irradiation aigüe. La première partie de ce travail concerne le choix de la méthode d'investigation. L'interaction entre une lumière cohérente et un milieu diffusant engendre un phénomène d'interférence appelé speckle. Une analyse fréquentielle classique sur le champ de speckle est complétée par une approche stochastique pour en extraire des paramètres caractérisant les figures de speckle. Dans la deuxième partie le protocole expérimental a été testé afin de mieux comprendre le comportement des paramètres en fonciton de quelques propriétés physiques de milieux diffusants synthétiques. Cette étude a révélé que certains des paramètres du speckle étaient plus influencés par les gros diffuseurs (Mie) alors que d'autres l'étaient par les plus petits (Rayleigh). La troisième partie concerne l'application de cette méthode in vivo au syndrome cutané d'irradiation aigüe chez le porc. L'analyse des résultats acquis lors du suivi de plusieurs animaux montre la possibilité de discriminer les zones irradiées des zones saines plusieurs semaines avant l'apparition des premiers signes cliniques. Enfin, pour comprendre les résultats obtenus sur la brûlure radiologique, nous avons confronté l'ensemble des résultats physiques et ceux obtenus par les analyses histologiques. / Overexposure to ionizing radiation is now a growing concern of clinicians. In case of external exposure, the skin is the first tissue exposed. However, there are no tools that can diagnose pathological tissue. The objective of this work is to demonstrate the possibility of using a non-invasive method for in vivo diagnosis and prognosis of acute cutaneous radiation syndrome. The first part of this work concerns the choice of the investigation method. Interaction of coherent light and scattering medium creates a phenomenon called speckle. A classical frequential analysis on the spekle field is supplemented by a stochastic approach to extract parameters characterizing speckle patterns. In the second part, the experimental setup has been tested in order to understand the parameters behavior in function of some physical properties of synthetic scattering media. The study revealed that some of the speckle parameters were more influenced by big scatterers (Mie) while others were by the smallest (Rayleigh). The third part concerns the in vivo application of this method on acute cutaneous radiation syndrome in pigs. Analysis of the results gained during the monitoring of several animals showeb the ability to discriminate between irradiated and healthy zones several weeks before apparition of firsts clinical signs. Finally, in order to understand the results on the radiological burn, we have confronted all physical results and those obtained by histological analyses.